阅读说明：本技术 密封帽的3d打印 (3D printing of sealing caps ) 是由 B·W·维尔金森 M·A·布巴斯 林仁和 于 2020-02-10 设计创作，主要内容包括：公开了使用三维打印制造密封帽的方法。所述密封帽用于密封紧固件。(A method of manufacturing a sealing cap using three-dimensional printing is disclosed. The sealing cap is used for sealing the fastener.)

1. A method of sealing a fastener comprising depositing a continuous layer comprising a first co-reactive composition directly onto the fastener by three-dimensional printing.

2. The method of claim 1, wherein the continuous layer is deposited to form a sealing cap.

3. The method of any one of claims 1 and 2, further comprising:

depositing a second coreactive composition directly onto said first coreactive composition; or

Depositing successive layers of the first and second coreactive compositions onto the fastener simultaneously.

4. The method of any of claims 1-3, further comprising applying a seal cap shell to the outermost deposited first co-reactive composition, wherein

The seal cap shell comprises an at least partially cured second co-reactive composition; and is

The second coreactive composition is the same or different than the outermost deposited coreactive composition.

5. The method of any one of claims 1 and 2, further comprising depositing a continuous layer of a second coreactive composition by three-dimensional printing to form the seal cap shell over the first coreactive composition.

6. A method of manufacturing a sealing cap, comprising:

depositing successive layers of a first co-reactive composition by three-dimensional printing to form a sealed cap shell defining an interior volume; and

filling the interior volume with a second co-reactive composition to provide a sealing cap.

7. The method of claim 6, wherein filling the internal volume comprises depositing the second co-reactive composition using three-dimensional printing.

8. A method according to any of claims 4 to 7, wherein the sealing cap shell is in the shape of a dome having a base width of from 5mm to 50mm, preferably from 10mm to 40 mm; a height of 5mm to 50mm, preferably 20mm to 40 mm; and an average wall thickness of 0.5mm to 25mm, preferably 1mm to 20mm, 1.5mm to 15mm or 2mm to 10 mm.

9. The process of any of claims 3-8 wherein said first coreactive composition is reactive with said second coreactive composition.

10. The process of any of claims 3-9 wherein said second coreactive composition is the same as said first coreactive composition.

11. The process of any of claims 3-9 wherein said second coreactive composition is different from said first coreactive composition.

12. The method of any of claims 6-11, further comprising at least partially curing the seal cap shell after forming the shell and before filling the interior volume.

13. The process of any of claims 3-12, wherein each of said first and second coreactive compositions independently comprises a sulfur-containing prepolymer.

14. The method of claim 13, wherein each of said first and second co-reactive compositions independently comprises from 40 wt% to 80 wt% of said sulfur-containing prepolymer.

15. The method of any one of claims 13-14, wherein the sulfur-containing prepolymer has a sulfur content of greater than 10 wt%, wherein wt% is based on the total weight of the sulfur-containing prepolymer.

16. The method of any one of claims 13-14, wherein the sulfur-containing prepolymer comprises a polythioether, a polysulfide, a sulfur-containing polyformal, a monosulfide, or a combination of any of the foregoing.

17. The method of any one of claims 3 to 16, wherein

Each of the first and second coreactive compositions independently comprises an actinic radiation curable coreactive composition; and is

The process further includes exposing the first and/or second coreactive compositions to actinic radiation prior to depositing the first and/or second coreactive compositions, while depositing the first and/or second coreactive compositions and/or after depositing the first and/or second coreactive compositions.

18. The method of any one of claims 1-16 wherein the first co-reactive composition is curable upon exposure to actinic radiation.

19. The method of any one of claims 3-16, where the first co-reactive composition is non-curable upon exposure to actinic radiation.

20. A sealing cap manufactured using the method of any one of claims 1 to 19.

21. The sealing cap of claim 20, wherein the fracture energy of the fully cured sealing cap is substantially the same as the fracture energy of the individual layers forming the sealing cap, wherein the fracture energy is determined according to ASTM D7313.

22. A sealing cap made using the method of any of claims 3-19, wherein a layer made from the first coreactive composition is chemically and/or physically bonded to a layer made from the second coreactive composition.

23. A method of sealing a fastener comprising applying the sealing cap of any of claims 20-22 over a fastener and allowing the first and/or second coreactive compositions to cure.

24. A fastener sealed with a sealing cap according to any one of claims 20 to 22.

25. The fastener of claim 24, wherein the fastener is on a vehicle, such as an aerospace vehicle.

Technical Field

The present disclosure relates to sealing fasteners, methods of manufacturing sealing caps, and sealing caps manufactured according to such methods.

Background

The sealing cap serves to seal and protect the fastener from environmental conditions. Depending on the application, it may be desirable for the sealing cap to exhibit one or more properties, including chemical resistance, corrosion resistance, hydrolytic stability, low temperature flexibility, high temperature resistance, and the ability to dissipate electrical charge. Fasteners such as rivets, bolts, screws, nuts, anchors, and washers of various shapes and sizes are used to secure the parts and may extend to varying degrees to the surface. It is useful to have a sealing cap that is optimized in material and size for a particular application.

Disclosure of Invention

According to the present invention, a method of sealing a fastener includes depositing a continuous layer including a first co-reactive composition directly onto the fastener by three-dimensional printing.

According to the present invention, a method of making a sealing cap includes depositing successive layers of a first co-reactive composition by three-dimensional printing to form a sealing cap shell defining an interior volume; and filling the interior volume with a second co-reactive composition to provide a sealing cap.

Sealing caps and sealing fasteners made according to the present method are also within the scope of the present invention.

Drawings

The drawings described herein are for illustration purposes only. The drawings are not intended to limit the scope of the present disclosure.

FIGS. 1A-1B show cross-sectional views of a sealing cap assembled over a fastener.

FIGS. 2A-2C show a perspective view of the exterior of a containment cap shell, a cross-sectional view of the containment cap shell, and a cross-sectional view of a co-reactive composition with an interior volume filling the shell, respectively.

Fig. 3A-3C show photographs of polyurea seal cap shells made according to the methods provided by the present disclosure.

Fig. 3D shows a confocal laser scanning micro surface profile (10X) of the corresponding seal cap shell shown in fig. 3A-3C.

Fig. 4 shows a photograph of a sealing cap shell made according to example 4.

Detailed Description

For purposes of the following detailed description, it is to be understood that the embodiments provided by the present disclosure may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

Moreover, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1 to 10" is intended to include all sub-ranges between the recited minimum value of 1 (inclusive) and the recited maximum value of 10 (inclusive), i.e., a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10.

"Alkanediyl" means a diradical of a saturated, branched or straight chain acyclic hydrocarbon group having, for example, from 1 to 18 carbon atoms (C)_1-18)1 to 14 carbon atoms (C)_1-14)1 to 6 carbon atoms (C)_1-6)1 to 4 carbon atoms (C)_1-4) Or 1 to 3 hydrocarbon atoms (C)_1-3). Alkanediyl may be C_2-14Alkanediyl, C_2-10Alkanediyl, C_2-8Alkanediyl, C_2-6Alkanediyl, C_2-4Alkanediyl or C_2-3An alkanediyl group. Examples of alkanediyl groups include methane-diyl (-CH)₂-), ethane-1, 2-diyl (-CH)₂CH₂-), propane-1, 3-diyl, and isopropane-1, 2-diyl (e.g., -CH₂CH₂CH₂-and-CH (CH)₃)CH₂-), butane-1, 4-diyl (-CH)₂CH₂CH₂CH₂-) pentane-1, 5-diyl (-CH)₂CH₂CH₂CH₂CH₂-), hexane-1, 6-diyl (-CH)₂CH₂CH₂CH₂CH₂CH₂-), heptane-1, 7-diyl, octane-1, 8-diyl, nonane-1, 9-diyl, decane-1, 10-diyl and dodecane-1, 12-diyl.

"Alkanoalkylene" means a saturated hydrocarbon group having one or more cycloalkyl and/or cycloalkanediyl groups and one or more alkyl and/or alkanediyl groups, wherein cycloalkyl, cycloalkanediyl, alkyl and alkanediyl are as defined herein. Each cycloalkyl and/or cycloalkanediyl group may be C_3-6、C_5-6Cyclohexyl or cyclohexanediyl. Each alkyl and/or alkanediyl group may be, for example, C_1-6、C_1-4、C_1-3Methyl, methanediyl, ethyl or ethane-1, 2-diyl. The alkane cycloalkane group may be, for example, C_4-18Alkane cycloalkane, C_4-16Alkane cycloalkane, C_4-12Alkane cycloalkane, C_4-8Alkane cycloalkane, C_6-12Alkane cycloalkane, C_6-10Alkane cycloalkane or C_6-9Alkane cycloalkane. Examples of the alkane cycloalkane group include 1,1,3, 3-tetramethylcyclohexane and cyclohexylmethane.

"Alkancyclane diradical" means a diradical of an alkanyl cycloalkane group. The alkanecycloalkanediyl group may be, for example, C_4-18Alkanecycloalkanediyl, C_4-16Alkanecycloalkanediyl, C_4-12Alkane ringAlkanediyl, C_4-8Alkanecycloalkanediyl, C_6-12Alkanecycloalkanediyl, C_6-10Alkanecycloalkanediyl or C_6-9Alkanecycloalkanediyl. Examples of alkanecycloalkanediyl groups include 1,1,3, 3-tetramethylcyclohexane-1, 5-diyl and cyclohexylmethane-4, 4' -diyl.

"alkylaromatic hydrocarbon" refers to a hydrocarbon group having one or more aryl and/or arylenediyl groups and one or more alkyl and/or alkanediyl groups, wherein aryl, arylenediyl, alkyl, and alkanediyl are defined herein. Each aryl and/or arene diyl group may be C_6-12、C_6-10Phenyl or benzenediyl. Each alkyl and/or alkanediyl group may be C_1-6、C_1-4、C_1-3Methyl, methanediyl, ethyl or ethane-1, 2-diyl. The alkane aromatic group may be C_6-18Alkane aromatic hydrocarbon, C_6-16Alkane aromatic hydrocarbon, C_6-12Alkane aromatic hydrocarbon, C_6-8Alkane aromatic hydrocarbon, C_6-12Alkane aromatic hydrocarbon, C_6-10Alkane-arene or C_6-9An alkane aromatic hydrocarbon. Examples of the alkane aromatic group include diphenylmethane.

"alkylaromatic diyl" refers to a diradical of an alkylaromatic hydrocarbon group. The alkylaromatic diyl group may be, for example, C_6-18Alkane-arene diyl, C_6-16Alkane-arene diyl, C_6-12Alkane-arene diyl, C_6-8Alkane-arene diyl, C_6-12Alkane-arene diyl, C_6-10Alkane-arene diyl or C_6-9An alkylaromatic diyl group. An example of an alkylaromatic diyl group includes diphenylmethane-4, 4' -diyl.

An "alkenyl" group refers to the structure-CR ═ C (R)₂Wherein an alkenyl group is a group and is bonded to a larger molecule. In such embodiments, each R may independently include, for example, hydrogen and C_1-3An alkyl group. Each R may be hydrogen, and the alkenyl group may have the structure-CH ═ CH₂。

"alkoxy" refers to the group-OR, where R is alkyl as defined herein. Examples of alkoxy groups include methoxy, ethoxy, n-propoxy, n-butoxy, and mixtures thereof,Isopropoxy and n-butoxy. The alkoxy group may be C_1-8Alkoxy radical, C_1-6Alkoxy radical, C_1-4Alkoxy or C_1-3An alkoxy group.

"alkyl" refers to a single radical of a saturated, branched, or straight chain acyclic hydrocarbon group having, for example, 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, 1 to 4 carbon atoms, or 1 to 3 carbon atoms. The alkyl group may be, for example, C_1-6Alkyl radical, C_1-4Alkyl or C_1-3An alkyl group. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-hexyl, n-decyl and tetradecyl. The alkyl group may be, for example, C_1-6Alkyl radical, C_1-4Alkyl and C_1-3An alkyl group.

"arenediyl" refers to a diradical monocyclic or polycyclic aromatic group. Examples of arenediyl groups include benzenediyl and naphthalenediyl. The arene diyl group may be, for example, C_6-12Aromatic diyl, C_6-10Aromatic diyl, C_6-9Arenediyl or benzenediyl.

"Cycloalkanediyl" refers to a diradical saturated monocyclic or polycyclic hydrocarbon group. The cycloalkanediyl group may be, for example, C_3-12Cycloalkanediyl group, C_3-8Cycloalkanediyl group, C_3-6Cycloalkanediyl or C_5-6A cycloalkanediyl group. Examples of cycloalkanediyl groups include cyclohexane-1, 4-diyl, cyclohexane-1, 3-diyl, and cyclohexane-1, 2-diyl.

"cycloalkyl" refers to a saturated monocyclic or polycyclic hydrocarbon mono-radical group. Cycloalkyl groups may be, for example, C_3-12Cycloalkyl radical, C_3-8Cycloalkyl radical, C_3-6Cycloalkyl or C_5-6A cycloalkyl group.

"Heteroalkanediyl" refers to alkanediyl groups in which one or more carbon atoms are replaced by a heteroatom such as N, O, S or P. In heteroalkanediyl, one or more heteroatoms may be N or O.

"Heterocycloalkyldiyl" refers to a cycloalkanediyl group in which one or more carbon atoms are replaced by a heteroatom such as N, O, S or P. In a heterocycloalkane diradical, one or more heteroatoms may be N or O.

The "backbone" of the prepolymer refers to the segment between the reactive functional groups. The prepolymer backbone typically comprises repeating subunits. For example, polythiols HS- [ R ]]_nThe main chain of-SH is- [ R ]]_n–。

"Co-reactive composition" refers to a composition that includes two or more co-reactive compounds that are capable of reacting at temperatures, for example, less than 50 ℃, less than 40 ℃, less than 30 ℃, or less than 20 ℃. The reaction between two or more compounds may be initiated by combining and mixing two or more co-reactive compounds and/or by exposing a co-reactive composition comprising two or more co-reactive compounds to a suitable catalyst or a suitable activated polymerization initiator, such as a photopolymerization initiator exposed to actinic radiation. Suitable catalysts and suitable polymerization initiators are capable of accelerating or initiating a chemical reaction between the co-reactive compounds. The catalyst may be a latent catalyst that can be activated by exposure to energy such as heat, actinic radiation, or mechanical forces such as shear forces. For example, a co-reactive composition may be formed by combining and mixing a first reactive component comprising a first reactive compound with a second reactive component comprising a second reactive compound, wherein the first reactive compound may react with the second reactive compound.

The "core" of a compound or polymer refers to the segment between reactive functional groups. For example, the core of the polythiol HS-R-SH is-R-. The core of the compound or prepolymer may also be referred to as the backbone of the compound or the backbone of the prepolymer. The core of the polyfunctionalizing agent may be an atom or structure, such as a cycloalkane, substituted cycloalkane, heterocycloalkane, substituted heterocycloalkane, arene, substituted arene, heteroarene or substituted heteroarene, to which a moiety having a reactive functional group is bonded.

"curing time" refers to the duration from, for example, the first initiation of the curing reaction of the coreactive composition by combining and mixing with the coreactive components to form the coreactive composition and/or by exposing the coreactive composition to actinic radiation to the point that a layer made from the coreactive composition exhibits a shore hardness of 30A at 25 ℃ and 50% RH. For actinic radiation curable compositions, cure time refers to the duration from the first exposure of the coreactive composition to actinic radiation to the layer prepared from the exposed coreactive composition exhibiting a shore hardness of 30A at 25 ℃ and 50% RH.

During curing, the co-reactive composition may be characterized by a working time, a tack free time, a cure onset, and a full cure. Working time or gel time refers to the time from initiation of the reaction between the ingredients, for example by mixing and/or activating the polymerization initiator, to when the co-reactive composition can no longer be stirred by hand. Tack free time refers to the time from the first initiation of the reaction between the ingredients to the time that the surface of the cured co-reactive composition is no longer tack free. The cure start time refers to the time from the reaction between the initiating ingredients to the curing of the coreactive composition to produce a measurable hardness. The full cure time may refer to the time for the cured composition to reach a hardness within 90% of the maximum hardness. These times may vary significantly depending on, for example, the components of the co-reactive composition, the cure chemistry, the temperature, the catalyst, the cure accelerator, and/or the presence of the photopolymerization initiator.

A dash ("-") that is not between two letters or symbols is used to indicate a substituent or a point of bonding between two atoms. For example, -CONH₂Attached through a carbon atom.

"derived from" as in "moiety derived from a compound" refers to the moiety that is produced when the parent compound reacts with the reactant. For example, the bis (alkenyl) compound CH₂＝CH–R–CH＝CH₂Can be reacted with another compound, such as a compound having a thiol group, to produce a moiety- (CH)₂)₂–R–(CH₂)₂-, which is derived from the reaction of an alkenyl group with a thiol group. As another example, for a parent diisocyanate having the structure O ═ C ═ N-N ═ C ═ O, the moiety derived from the diisocyanate has the structure-C (O) -NH-R-NH-C (O) -.

"derived from the reaction of-V with a thiolBy "is meant the moiety-V' -resulting from the reaction of a thiol group with a moiety comprising a functional group reactive with a thiol group. For example, the group V-may comprise CH₂＝CH–CH₂-O-wherein the alkenyl radical CH₂CH-may be reacted with a thiol group-SH. When reacted with a thiol group, the moiety-V' -is-CH₂–CH₂–CH₂–O–。

Glass transition temperature T_gDetermined by Dynamic Mechanical Analysis (DMA) using a TA Instruments Q800 apparatus (frequency 1Hz, amplitude 20 microns, and temperature ramp-80 ℃ to 25 ℃), in which T is_gIdentified as the peak of the tan delta curve.

Monomers refer to low molecular weight compounds and may have a molecular weight of, for example, less than 1,000Da, less than 800Da, less than 600Da, less than 500Da, less than 400Da, or less than 300 Da. The monomers may have a molecular weight of, for example, 100Da to 1,000Da, 100Da to 800Da, 100Da to 600Da, 150Da to 550Da, or 200Da to 500 Da. The monomers may have a molecular weight greater than 100Da, greater than 200Da, greater than 300Da, greater than 400Da, greater than 500Da, greater than 600Da, or greater than 800 Da. The monomer may have two or more reactive functionalities, for example 2 to 6,2 to 5, or 2 to 4. The monomer may have a functionality of 2,3, 4, 5,6, or a combination of any of the foregoing. The monomers may have an average reactive functionality of, for example, 2 to 6,2 to 5, 2 to 4, 2 to 3, 2.1 to 2.8, or 2.2 to 2.6. Reactive functionality refers to the number of reactive groups per molecule. Combinations of compounds having different reactive functionalities may be characterized by an average non-integer reactive functionality.

"polyalkenyl" refers to a compound having at least two alkenyl groups. At least two alkenyl groups may be terminal alkenyl groups, and such alkenyl groups may be referred to as alkenyl-terminated compounds. The alkenyl group may also be a pendant alkenyl group. The alkenyl group may be a dienyl group having two alkenyl groups. The polyalkenyl group can have more than two alkenyl groups, for example three to six alkenyl groups. The polyalkenyl group may comprise a single type of polyalkenyl group, may be a combination of polyalkenyl groups having the same alkenyl functionality, or may be a combination of polyalkenyl groups having different alkenyl functionalities.

"prepolymer" refers to both homopolymers and copolymers. For thiol-terminated prepolymers, the molecular weight is the number average molecular weight "Mn" as determined by end group analysis using iodometric titration. For non-thiol-terminated prepolymers, the number average molecular weight is determined by gel permeation chromatography using polystyrene standards. The prepolymer includes a backbone and reactive functional groups capable of reacting with another compound, such as a curing agent or a crosslinking agent, to form a cured polymer. The prepolymer comprises a plurality of repeating subunits bonded to each other, which may be the same or different. The multiple repeating subunits form the backbone of the prepolymer.

The polyfunctionalizing agent may have the structure of formula (1):

B(–V)_z (1)

wherein B is the core of a polyfunctionalizing agent, each V is a moiety blocked in a reactive functional group such as a thiol group, alkenyl group, epoxy group, isocyanate group, or michael acceptor group, and z is an integer from 3 to 6, for example 3,4, 5, or 6. In the polyfunctionalizing agent of formula (1), each-V may have, for example, -R-SH or-R-CH ═ CH₂Wherein R may be, for example, C_2-10Alkanediyl, C_2-10Heteroalkanediyl, substituted C_2-10Alkanediyl or substituted C_2-10A heteroalkanediyl group. When part V reacts with another compound, part-V is produced¹- (said to be derived from reaction with another compound). When V is-R-CH ═ CH₂And when reacted with, for example, thiol groups, moieties V¹is-R-CH₂–CH₂-, derived from the reaction.

The specific gravity is determined according to ISO 787-11.

Shore A hardness was measured according to ASTM D2240 using a type A durometer.

"substituted" refers to groups in which one or more hydrogen atoms are each independently replaced with the same or different substituents. Substituents may include halogen, -S (O)₂OH、–S(O)₂-SH, -SR, wherein R is C_1-6Alkyl, -COOH, -NO₂、–NR₂Wherein each R independently comprises hydrogen and C_1-3Alkyl, -CN, ═ O, C_1-10Alkyl, -CF₃-OH, phenyl, C_2-6Heteroalkyl group, C_5-6Heteroaryl group, C_1-10Alkoxy or-COR, wherein R is C_1-10An alkyl group. The substituent may be-OH, -NH₂Or C_1-10An alkyl group.

"tack free time" refers to the time from the first initiation of the curing reaction of the coreactive composition to the point where a layer made from the coreactive composition is no longer tack free as determined by applying polyethylene sheet to the surface of the layer by hand pressure and observing whether the sealant adheres to the surface of the polyethylene sheet, wherein the layer is considered to be tack free if the polyethylene sheet is easily separated from the layer. For actinic radiation curable coreactive compositions, tack free time refers to the time from exposure of the coreactive composition to actinic radiation until a layer prepared from the coreactive composition is no longer tack free.

Tensile strength and elongation were measured according to AMS 3279.

"transmission" refers to the ability to transmit a portion of the electromagnetic spectrum in the range of 360nm to 750nm, greater than 20%, greater than 30%, greater than 40%, or greater than 50% of the incident radiation.

Reference is now made to certain compounds, compositions, devices and methods of the present invention. The disclosed compounds, compositions, devices, and methods are not intended to limit the claims. On the contrary, the claims are intended to cover all alternatives, modifications, and equivalents.

The methods provided by the present disclosure include methods of manufacturing sealing caps using three-dimensional printing. The sealing cap can be manufactured by depositing the co-reactive composition directly onto the fastener using three-dimensional printing. The deposited coreactive composition forms a sealing cap, and/or a sealing cap shell can be applied over the faster deposited coreactive composition to form a sealing cap. The sealing cap shell may be manufactured using three-dimensional printing. The sealing cap can also be made by depositing successive layers of a coreactive composition to form a sealing cap shell and filling the interior volume defined by the sealing cap shell with an additional coreactive composition, which can be the same as or different from the first coreactive composition. A sealing cap containing a sealing cap shell and a fill interior can then be assembled over the fastener to seal the fastener.

In the context of the present disclosure, "sealing a fastener" and similar terms refer to the process of placing a co-reactive composition over a fastener such that the co-reactive composition conforms to the surface of the fastener and provides a barrier after curing that minimizes contact of liquids such as water, solvents, and fuels with the fastener during the design life of the seal.

The sealing cap is typically a dome-shaped structure that fits over an extension of the fastener above the surface. Cross-sectional views of the sealing cap and fastener are shown in fig. 1A and 1B. FIG. 1A shows a view of a sealing cap 101 having an outer layer forming a shell 102 and an inner layer 103 surrounding a fastener 104 mounted to a surface 105. FIG. 1B shows a view of another example of a sealing cap with a single layer 106 surrounding a fastener 104 mounted to a surface 105.

Views of the seal cap housing are shown in fig. 2A-2C. Fig. 2A shows a perspective view of the outer surface 202 of the sealing cap shell 201. Fig. 2B shows a cross-sectional view of the outer layer 203 of the capsule defining the interior volume 204. As shown in fig. 2C, internal volume 204 can be filled with a co-reactive composition 205 to fill the volume and prepare for assembly onto a fastener.

To seal the fastener, a sealing cap as shown in fig. 2C may be applied over the fastener before the internal co-reactive composition 205 is fully cured. The sealing cap shell 203 can be at least partially cured to retain the co-reactive composition 205 therein and allow the sealing cap to be manipulated manually or automatically. The outer surface of the seal cap shell may be at least partially cured or fully cured; and the inner surface of the seal cap shell may be at least partially uncured or completely uncured when applied to the fastener. The seal cap shell may also be fully cured before the seal cap is assembled over the fastener. Internal coreactive composition 205 can be uncured or at least partially uncured so that a sealing cap can be applied over the fastener, and internal coreactive composition 205 has a viscosity low enough so that internal coreactive composition 205 conforms to the contours of the fastener and other components such as bolts, washers, and surfaces to cover the fastener to form a viable seal. It is generally desirable that the internal coreactive composition contact the surface of the fastener and substrate without any air gaps, voids, and/or air bubbles. After assembly of the sealing cap to the fastener, the sealing cap shell and the inner coreactive composition may be fully cured such that the coreactive composition has not yet fully cured to seal the fastener.

The sealing cap may have a dome shape sized to cover a particular fastener. For example, the width of the base of the sealing cap (element 208 in fig. 2B) may be, for example, 5mm to 60mm, 10mm to 40mm, or 20mm to 30 mm. The base of the sealing cap may be sized, for example, greater than 5mm, greater than 10mm, greater than 20mm, greater than 30mm, or greater than 40 mm. The base of the sealing cap may be, for example, less than 10mm, less than 20mm, less than 30mm, less than 40mm, or less than 50 mm. The height of the sealing cap may be, for example, 5mm to 50mm, 10mm to 40mm, or 20mm to 30 mm. The height of the sealing cap may be, for example, greater than 5mm, greater than 10mm, greater than 20mm, greater than 30mm, greater than 40mm, or greater than 50 mm. The height of the sealing cap may be, for example, less than 10mm, less than 20mm, less than 30mm, less than 40mm, or less than 50 mm.

The sealing cap shell may have an average thickness of, for example, 0.5mm to 25mm, 1mm to 20mm, 1.5mm to 15mm, or 2mm to 10 mm. The sealing cap shell may have an average thickness (207) of, for example, greater than 0.5mm, greater than 1mm, greater than 2mm, greater than 5mm, greater than 10mm, greater than 15mm, or greater than 20 mm. The sealing cap shell may have an average thickness of, for example, less than 1mm, less than 2mm, less than 5mm, less than 10mm, less than 15mm, or less than 20 mm.

The sealing cap may be configured to seal the fastener from exposure to solvents such as fuel and hydraulic fluid during use. For example, it may be desirable for the surface of the fastener to be covered with at least 5mm of the cured solvent-resistant composition.

The sealing caps provided by the present disclosure may be manufactured using three-dimensional printing. Three-dimensional printing encompasses various automated manufacturing processes in which processor-controlled automated processes are used to form three-dimensional articles. A three-dimensional printing process for making a sealing cap includes depositing one or more co-reactive compositions in successive layers to form a sealing cap.

In a first method of making a sealing cap, a continuous layer of a first coreactive composition can be deposited directly on a fastener, and the deposited first coreactive composition allowed to cure in situ on the fastener to form the sealing cap.

The sealing cap can be formed by depositing a first coreactive composition onto the fastener and then depositing a second coreactive composition over the first coreactive composition to form the sealing cap. The first coreactive composition may be fully cured, partially cured, or may remain uncured prior to depositing the second coreactive composition.

The first and second coreactive compositions can be deposited simultaneously, such as by independently depositing the first and second coreactive compositions using separate printing nozzles, or by co-extruding the first and second coreactive compositions and optionally additional coreactive compositions through a single co-extrusion nozzle.

The first and second coreactive compositions may have the same curing chemistry or may have different curing chemistries. Each of the first and second coreactive compositions can independently include a compound capable of reacting with a compound in the other coreactive composition.

The co-reactive composition may include a first compound having a first functional group and a second compound having a second functional group, wherein the functional groups react to form a cured polymer network. For co-reactive compositions having the same cure chemistry, the first functional group and the second functional group in both co-reactive compositions will be the same. For example, both the first and second coreactive compositions may be based on thiol/ene chemistry.

For coreactive compositions that do not have the same curing chemistry but include compounds capable of coreaction, the first functional group in both coreactive compositions may be the same, and the second functional group may be different and capable of coreaction with the first functional group. As an example, the first functional group can be a thiol group, and in the first co-reactive composition, the second functional group can be an alkenyl group, and in the second co-reactive composition, the second functional group can be an epoxy group. The second functional groups in the first and second coreactive compositions are different, but still capable of reacting with the common first functional group (i.e., the thiol group).

By selecting a first coreactive composition and a second coreactive composition that can be coreactive, chemical bonding between the coreactants can occur during curing. Chemical bonding at the interface between the first and second coreactive compositions combines the two coreactive compositions to provide a robust interface. While chemical bonding may occur between the cured and uncured coreactive compositions, it is desirable that the first and second coreactive compositions, or at least a portion of the coreactive compositions at the interface, remain uncured or at least partially uncured when they are initially combined, and then simultaneously cured to increase the degree of reaction between the compounds at the interface between the two coreactive compositions and thereby increase the chemical bonding between adjacent coreactive compositions. Bonding between adjacent coreactive compositions can occur by physical means, such as by entanglement and/or migration of the components between the layers.

Sealing caps made by depositing one or more coreactive compositions directly onto a fastener using coreactive three-dimensional printing can minimize the gap between the fastener and the coreactive compositions. The cure chemistry and viscosity of the co-reactive composition can be selected to make it flow and conform to the complex geometry of the fastener, and the three-dimensional printing process can be designed to continuously remove air that might otherwise become trapped between the fastener surface and the sealant. Co-reactive three-dimensional printing may also facilitate the use of various curing chemistries and prepolymers that are not readily accessible using the curing methods used to make the sealing caps. For example, current methods of manufacturing sealing caps may involve UV curing of the sealant composition. To facilitate UV-initiated curing, the curing chemistry is typically based on free radical polymerization, and the sealant composition must be transmissive to allow UV radiation to penetrate the depth of the sealant. Thus, the cure chemistry and sealant composition of the UV-curable sealing cap may be limited. As disclosed herein, the ability to manufacture a sealing cap having multiple layers, wherein the desired properties of each layer are optimized to provide a certain function, can provide a sealing cap having superior performance attributes (as compared to a sealing cap formed from a single composition). Furthermore, the use of a co-reactive composition capable of co-reacting and forming a chemically bonded layer may provide strong interfacial integrity and thereby enhance the reliability of the three-dimensional printed sealing cap under harsh aerospace use conditions. Furthermore, the use of three-dimensional printing to deposit the sealant composition directly onto the fastener to fabricate the sealing cap avoids the logistics of storing pre-formed sealing caps (which can be of various shapes and sizes). The direct in situ fabrication of sealing caps using three-dimensional printing under semi-automated or fully automated control facilitates the ability of an operator to fabricate sealing caps on fasteners having a variety of different shapes and sizes.

The sealing cap may be made by: the method includes depositing a first coreactive composition directly onto the fastener using three-dimensional printing, applying a pre-fabricated seal cap shell over the deposited first coreactive composition, and curing the first coreactive composition and optionally curing the seal cap shell (as needed) to seal the fastener.

As with the first method, one or more coreactive compositions can be deposited directly onto the fastener either sequentially or simultaneously. Three-dimensional printing may be used to fabricate a preformed hermetic cap shell by depositing successive layers of the second co-reactive composition or by other means. At least the outer surface of the seal cap shell may be at least partially cured for ease of handling. The inner surface of the seal cap shell may be partially cured or uncured so that the first co-reactive composition is capable of chemically bonding to the seal cap shell. The preformed sealing cap shell may be fully cured. The preformed seal cap shell may include a second coreactive composition, which may be the same or different from the deposited coreactive composition, have the same or different cure chemistry as the deposited coreactive composition, be capable of co-reacting with the deposited coreactive composition, or may not react with the deposited coreactive composition.

The method of sealing a fastener provided by the present disclosure further comprises depositing a continuous layer of a first co-reactive composition by three-dimensional printing to form a sealing cap shell defining an interior volume; and filling the interior volume with a second co-reactive composition to provide a sealing cap that can be secured over the fastener and cured to seal the fastener.

The first and second coreactive compositions may be the same or different and may have the same or different cure chemistries. The first and second coreactive compositions may or may not be coreactive with each other.

The seal cap shell may be partially cured or fully cured while the interior volume is filled with the second coreactive composition. To facilitate chemical bonding between the seal cap shell and the second coreactive composition, it may be desirable that at least a portion of the first coreactive composition forming the interior surface of the seal cap shell not be fully cured. Further, to facilitate chemical bonding between the closure shell and the second coreactive composition, the first coreactive composition can include a compound capable of reacting with a compound in the second coreactive composition.

Filling the interior volume of the sealing cap with the second co-reactive composition may include depositing the second co-reactive composition into the interior volume using three-dimensional printing or other methods such as extrusion or filling using a spatula or other tool.

The second coreactive composition that fills the interior volume of the sealing cap can have a viscosity that facilitates the ability of the second coreactive composition to conform to the surface of the fastener (minimizing, if not eliminating, voids or air pockets). The second co-reactive composition may be uncured or partially cured while the sealing cap is placed over the fastener.

After placement over the fastener, the closure cap shell and the interior second coreactive composition may be cured by any suitable method suitable for the curing chemistry of the first and second coreactive compositions.

As a modification of the present method, the sealing cap may be manufactured by depositing successive layers of co-reactive three-dimensional printing to form the sealing cap. In the present method, the sealing cap is manufactured as one piece and there are no separate steps for manufacturing the sealing cap shell and filling the interior volume. In the present method, the outer surface of the sealing cap may be partially or fully cured to facilitate handling of the sealing cap and placement thereof onto the fastener. The co-reactive composition in the interior volume of the sealing cap may remain uncured or partially uncured so that the uncured co-reactive composition is able to conform to and cover the fastener.

In the present method, the outer portion, the intermediate portion, and/or the inner portion of the sealing cap may comprise the same or different co-reactive compositions, may have the same or different curing chemistries, and/or may be co-reactive with other portions of the sealing cap. For example, the outer portion of the sealing cap may have a fast cure rate and the inner portion may have a slow cure rate. Here, fast and slow cure rates refer to the relative cure rates of the different parts of the sealing cap. For example, the outer portion of the sealing cap may have a shorter working time or gel time and a short tack-free time than the inner portion of the sealing cap. The provision of the outer portion of the sealing cap may facilitate the ability of the sealing cap to retain its shape and facilitate handling. The slower curing rate of the inner portion of the sealing cap may allow time for the material properties to develop sufficiently. As another example, the outer surface may be rapidly cured upon exposure to actinic radiation to facilitate handling of the sealing cap.

A pre-fabricated sealing cap may be applied to a fastener comprising one or more layers of three-dimensional printed material. The printed material can conform to the complex surface of the fastener and provide a conformal or smooth surface to which the pre-manufactured sealing cap can be applied. By using a co-reactive composition, bonding between layers can be enhanced.

The co-reactive composition used to make the sealing cap, the sealing cap shell, and/or to fill the internal volume may include a prepolymer having any suitable backbone, a prepolymer having any suitable reactive functional group, a co-reactive compound based on any suitable curing chemistry, and/or any suitable additive.

The first and second coreactive compositions can include, for example, prepolymers having the same or different prepolymer backbones, prepolymers having the same or different reactive functional groups, coreactive compounds having the same or different cure chemistries, coreactive compounds having different cure rates, and/or the same or different additives. For example, the first and second coreactive compositions can include different types of ingredients and/or different amounts of ingredients. For example, a first coreactive composition can comprise a first wt% of one or more ingredients, and a second coreactive composition can comprise a second wt% of one or more ingredients, where the first wt% is the same as or different from the second wt% of at least one ingredient, and the wt% is based on the total weight of the corresponding coreactive composition.

As another example, a first coreactive composition can comprise a first vol% of one or more ingredients, and a second coreactive composition can comprise a second vol% of one or more ingredients, wherein the first vol% is the same as or different from the second vol% of at least one ingredient, and the wt% is based on the total volume of the respective coreactive compositions.

Similarly, when cured, the first and second coreactive compositions may have the same or different material properties, including, for example, solvent resistance, physical properties, and/or specific gravity.

The first and second coreactive compositions can include compounds capable of reacting with compounds in another coreactive composition.

The co-reactive composition may include a first compound having a first functional group and a second compound including a second functional group, wherein the first functional group is reactive with the second functional group. The first and second compounds may independently comprise a monomer, a combination of monomers, a prepolymer, a combination of prepolymers, or a combination thereof.

The co-reactive composition may include, for example, a one-part co-reactive composition in which the reaction between the co-reactive compounds is initiated by exposure to energy, such as actinic radiation.

The coreactive composition may be formed by combining and mixing a first coreactive component comprising a first compound having a first functional group and a second coreactive component comprising a second compound having a second functional group, wherein the first and functional groups are reactive with the second functional group.

The co-reactive composition may include a co-reactive compound capable of reacting at a temperature of less than 50 ℃, e.g., less than 40 ℃, less than 30 ℃, less than 20 ℃, or less than 10 ℃ without exposure to actinic radiation or subsequent exposure to actinic radiation. For example, the co-reactive compounds may be reacted at a temperature of 5 ℃ to 50 ℃,10 ℃ to 40 ℃, or 15 ℃ to 25 ℃, or 20 ℃ to 30 ℃. The co-reactive composition may include co-reactive compounds that co-react and cure at room temperature, where room temperature refers to a temperature of 20 ℃ to 25 ℃, 20 ℃ to 22 ℃, or about 20 ℃.

Co-reactive compositions at 25 ℃ and 0.1 second^-1To 100 seconds^-1The viscosity at a shear rate of (A) is, for example, 200cP to 50,000,000cP, 200cP to 20,000,000cP, 1,000cP to 18,000,000cP, 5,000cP to 15,000,000cP, 5,000cP to 10,000,000cP, 5,000cP to 5,000,000cP, 5,000cP to 100,000cP, 5,000cP to 50,000cP, 5,000cP to 20,000cP, 6,000cP to 15,000cP, 7,000cP to 13,000cP, or 8,000cP to 12,000 cP. Co-reactive compositions at 25 ℃ and 0.1 second^-1To 100 seconds^-1For example, greater than 200cP, greater than 1,000cP, greater than 10,000cP, greater than 100,000cP, greater than 1,000,000cP, or greater than 10,000,000 cP. Co-reactive compositions at 25 ℃ and 0.1 second^-1To 100 seconds^-1For example, less than 100,000,000cP, less than 10,000,000cP, less than 1,000,000cP, less than 100,000cP, less than 10,000cP, or less than 1,000 cP. Viscosity values Using an Anton Paar MCR 302 rheometer at a temperature of 25 ℃ and 100 seconds^-1Measured at a 1mm gap at a shear rate of (c).

The coreactive composition may be formulated into a sealant composition that forms a sealant upon curing.

By sealant is meant a sealant capable of resisting atmospheric conditions such as moisture and temperature and/or at least partially blocking water, solvents, fuel, hydraulic fluid flowAnd other materials for the transport of materials such as liquids and gases. The sealant may exhibit chemical resistance, such as resistance to fuels and hydraulic fluids. For example, the chemical resistant material may exhibit a% swelling of less than 25%, less than 20%, less than 15%, or less than 10% after immersion in a chemical at 70 ℃ for 7 days, as determined according to EN ISO 10563. The sealant may exhibit type I or type I to Jet Reference Fluid (JRF)Resistance of LD-40 hydraulic fluid.

It may be desirable for the outer portion of the sealing cap, such as the sealing cap shell, or the outer portion of the multi-layer sealing cap to include a sealant. The outer portion of the sealing cap exposed to the environment may act as a solvent resistant barrier. The interior portion of the sealing cap adjacent the fastener may or may not include a sealant formulation. Depending on the design, the interior portion of the sealing cap may include the cured co-reactive composition deposited directly onto the fastener, or may include the cured co-reactive composition deposited into the interior volume of the sealing cap shell, which is then assembled onto the fastener.

The outer portion of the sealing cap may comprise a first sealant and the inner portion may comprise a second sealant, wherein the first and second sealants may be the same or different.

The prepolymers used in the co-reactive compositions provided by the present disclosure may have a number average molecular weight of, for example, less than 20,000Da, less than 15,000Da, less than 10,000Da, less than 8,000Da, less than 6,000Da, less than 4,000Da, or less than 2,000 Da. The prepolymer can have a number average molecular weight of, for example, greater than 2,000Da, greater than 4,000Da, greater than 6,000Da, greater than 8,000Da, greater than 10,000Da, or greater than 15,000 Da. The prepolymer can have a number average molecular weight of, for example, 1,000Da to 20,000Da, 2,000Da to 10,000Da, 3,000Da to 9,000Da, 4,000Da to 8,000Da, or 5,000Da to 7,000 Da.

The prepolymers used in the co-reactive compositions provided by the present disclosure can be liquid at 25 ℃ and can have a glass transition temperature Tg of, for example, less than-20 ℃, less than-30 ℃, or less than-40 ℃.

The prepolymers used in the co-reactive compositions provided by the present disclosure may exhibit viscosities, for example, in the range of 20 poise to 500 poise (2 pa-sec to 50 pa-sec), 20 poise to 200 poise (2 pa-sec to 20 pa-sec), or 40 poise to 120 poise (4 pa-sec to 12 pa-sec) at 25 ℃.

The co-reactive composition may comprise a prepolymer having any suitable polymeric backbone. For example, the polymeric backbone may be selected to impart solvent resistance to the cured co-reactive composition, to impart desired physical properties such as tensile strength, elongation%, Young's modulus, impact resistance, or other application-related properties. The prepolymer backbone may be terminated with one or more suitable functional groups appropriate to the particular curing chemistry.

For example, the prepolymer backbone may include polythioethers, polysulfides, polyformals, polyisocyanates, polyureas, polycarbonates, polyphenylene sulfides, polyethylene oxides, polystyrenes, acrylonitrile-butadiene-styrene, polycarbonates, styrene acrylonitrile, poly (methyl methacrylate), polyvinyl chloride, polybutadiene, polybutylene terephthalate, poly (p-phenylene oxide), polysulfone, polyethersulfone, polyethyleneimine, polyphenylsulfone, acrylonitrile styrene acrylate, polyethylene, syndiotactic or isotactic polypropylene, polylactic acid, polyamide, ethylene-vinyl acetate homopolymers or copolymers, polyurethane, ethylene copolymers, propylene impact copolymers, polyetheretherketone, polyoxymethylene, Syndiotactic Polystyrene (SPS), polyphenylene sulfide (PPS), Liquid Crystal Polymers (LCP), butene homopolymers and copolymers, poly (phenylene sulfide), poly (butylene oxide), poly (phenylene oxide), poly (butylene oxide), poly (phenylene oxide), poly (butylene oxide), poly (phenylene oxide), poly (phenylene oxide), poly (styrene), poly (butylene oxide), poly (phenylene oxide), poly (butylene oxide), poly (styrene), poly (butylene oxide), poly (butylene oxide, Hexene homopolymers and copolymers; and combinations of any of the foregoing.

Examples of other suitable prepolymer backbones include polyolefins (e.g., polyethylene, Linear Low Density Polyethylene (LLDPE), Low Density Polyethylene (LDPE), high density polyethylene, polypropylene, and olefin copolymers), styrene/butadiene rubber (SBR), styrene/ethylene/butadiene/styrene copolymer (SEBS), butyl rubber, ethylene/propylene copolymer (EPR), ethylene/propylene/diene monomer copolymer (EPDM), polystyrene (including high impact polystyrene), poly (vinyl acetate), ethylene/vinyl acetate copolymer (EVA), poly (vinyl alcohol), ethylene/vinyl alcohol copolymer(EVOH), poly (vinyl butyral), poly (methyl methacrylate), and other acrylate polymers and copolymers (including, for example, methyl methacrylate polymers, methacrylate copolymers, polymers derived from one or more acrylates, methacrylates, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, and the like), olefin and styrene copolymers, acrylonitrile/butadiene/styrene (ABS), styrene/acrylonitrile polymers (SAN), styrene/maleic anhydride copolymers, isobutylene/maleic anhydride copolymers, ethylene/acrylic acid copolymers, poly (acrylonitrile), Polycarbonate (PC), polyamides, polyesters, Liquid Crystal Polymers (LCP), poly (lactic acid), poly (phenylene oxide) (PPO), PPO-polyamide alloys, poly (phenylene oxide-co-polymers), poly (ethylene-co-polymers), poly (propylene oxide) (PPO), poly (ethylene-co-polymers), poly (ethylene-styrene copolymers, poly (ethylene-styrene-co-styrene copolymers, poly (ethylene-styrene) copolymers, poly (ethylene-styrene-co-styrene copolymers, poly (ethylene-styrene-co-copolymers, poly (propylene oxide) and the like, Polysulfones (PSU), polyether ketones (PEK), polyether ether ketones (PEEK), polyimides, Polyoxymethylene (POM) homopolymers and copolymers, polyetherimides, fluorinated ethylene propylene polymers (FEP), poly (vinyl fluoride), poly (vinylidene chloride) and poly (vinyl chloride), polyurethanes (thermoplastic and thermoset), aramids (e.g.,and) Polytetrafluoroethylene (PTFE), polysiloxanes (including polydimethyisiloxane, dimethylsiloxane/vinylmethylsiloxane copolymers, vinyldimethylsiloxane-terminated poly (dimethylsiloxane)), elastomers, epoxy polymers, polyureas, alkyds, cellulosic polymers (e.g., ethyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate), polyethers and diols such as poly (ethylene oxide) (also known as poly (ethylene glycol)), poly (propylene oxide) (also known as poly (propylene glycol)), and ethylene oxide/propylene oxide copolymers, acrylic latex polymers, polyester acrylate oligomers and polymers, polyester glycol diacrylate polymers, and UV curable resins.

The co-reactive composition may include a prepolymer that includes an elastomeric backbone.

"elastomer," "elastic," and the like refer to materials that have "rubbery" properties and generally have a low young's modulus and a high tensile strain. The elastomer may have a tensile strain (elongation at break) of about 100% to about 2,000%. The elastomer may exhibit a tear strength of, for example, 50 to 200kN/m, as determined according to ASTM D624. The Young's modulus of the elastomer may be in the range of, for example, 0.5MPa to 30MPa, for example 1MPa to 6MPa, as determined according to ASTM D412.4893.

Examples of suitable prepolymers having an elastomeric backbone include polyethers, polybutadienes, fluoroelastomers, perfluoroelastomers, ethylene/acrylic acid copolymers, ethylene propylene diene terpolymers, nitriles, polythioamines, polysiloxanes, chlorosulfonated polyethylene rubber, isoprene, chloroprene, polysulfides, polythioethers, silicones, styrene butadiene, and combinations of any of the foregoing. The elastomeric prepolymer may comprise a polysiloxane such as polymethylhydrosiloxane, polydimethylsiloxane, polyethylhydrosiloxane, polydiethylsiloxane, or a combination of any of the foregoing. The elastomeric prepolymer may include functional groups, such as silanol groups, that have low reactivity with amine and isocyanate groups.

The co-reactive composition may include a sulfur-containing prepolymer or a combination of sulfur-containing prepolymers. The sulfur-containing prepolymer can impart fuel resistance to the cured sealant.

"Sulfur-containing prepolymer" means a prepolymer having one or more thioether-S groups in the backbone of the prepolymer_n-prepolymers of groups, wherein n may be, for example, 1 to 6. Prepolymers that contain only thiol or other sulfur-containing groups as terminal or pendant groups of the prepolymer are not included in the sulfur-containing prepolymers. The prepolymer backbone refers to the portion of the prepolymer having repeating segments. Thus, having the structure HS-R-R (-CH)₂–SH)–[–R–(CH₂)₂–S(O)₂–(CH₂)–S(O)₂]_n–CH＝CH₂The prepolymer of (2) (wherein each R is a moiety not containing a sulfur atom) is not included in the sulfur-containing prepolymer. Having the structure HS-R-R (-CH)₂–SH)–[–R–(CH₂)₂–S(O)₂–(CH₂)–S(O)₂]–CH＝CH₂Wherein at least one R is a moiety containing a sulfur atom without any sulfur-containing moiety such as a thioether group is encompassed in the sulfur-containing prepolymer.

Sulfur-containing prepolymers with high sulfur content can impart chemical resistance to the cured coreactive composition. For example, the sulfur-containing prepolymer backbone can have a sulfur content of greater than 10 wt.%, greater than 12 wt.%, greater than 15 wt.%, greater than 18 wt.%, greater than 20 wt.%, or greater than 25 wt.%, wherein wt.% is based on the total weight of the prepolymer backbone. The chemically resistant prepolymer backbone can have a sulfur content of, for example, 10 wt% to 25 wt%, 12 wt% to 23 wt%, 13 wt% to 20 wt%, or 14 wt% to 18 wt%, where wt% is based on the total weight of the prepolymer backbone.

The co-reactive composition can include, for example, 40 wt% to 80 wt%, 40 wt% to 75 wt%, 45 wt% to 70 wt%, or 50 wt% to 70 wt% of a sulfur-containing prepolymer or combination of sulfur-containing prepolymers, where the wt% is based on the total weight of the co-reactive composition. The coreactive composition can include, for example, greater than 40 wt%, greater than 50 wt%, greater than 60 wt%, greater than 70 wt%, greater than 80 wt%, or greater than 90 wt% of a sulfur-containing prepolymer or combination of sulfur-containing prepolymers, where the wt% is based on the total weight of the coreactive composition. The coreactive composition can include, for example, less than 90 wt%, less than 80 wt%, less than 70 wt%, less than 60 wt%, less than 50 wt%, or less than 40 wt% of a sulfur-containing prepolymer or combination of sulfur-containing prepolymers, where the wt% is based on the total weight of the coreactive composition.

Examples of prepolymers having a sulfur-containing backbone include polythioether prepolymers, polysulfide prepolymers, sulfur-containing polyformal prepolymers, monosulfide prepolymers, and combinations of any of the foregoing.

The co-reactive composition may include a polythioether prepolymer or a combination of polythioether prepolymers.

The polythioether prepolymer can include a polythioether prepolymer comprising at least one portion having the structure of formula (2), a thiol-terminated polythioether prepolymer of formula (2a), a terminal-modified polythioether of formula (2b), or a combination of any of the foregoing:

-S-R¹-[S-A-S-R¹-]_n-S- (2)

HS-R¹-[S-A-S-R¹-]_n-SH (2a)

R³-S-R¹-[S-A-S-R¹-]_n-S-R³ (2b)

wherein

n may be an integer from 1 to 60;

each R³May independently be a moiety comprising a terminal reactive group;

each R¹Can be independently selected from C_2-10Alkanediyl, C_6-8Cycloalkanediyl group, C_6-14Alkanecycloalkanediyl, C_5-8Heterocyclane diyl and- [ (CHR)_p-X-]_q(CHR)_r-, wherein

p may be an integer from 2 to 6;

q may be an integer from 1 to 5;

r may be an integer from 2 to 10;

each R may be independently selected from hydrogen and methyl; and is

Each X may be independently selected from O, S and S-S; and is

Each a may independently be a moiety derived from a polyvinyl ether of formula (3) and a polyalkenyl polyfunctionalizing agent of formula (4):

CH₂＝CH-O-(R²-O)_m-CH＝CH₂ (3)

B(-R⁴-CH＝CH₂)_z (4)

wherein

m may be an integer of 0 to 50;

each R²Can be independently selected from C_1-10Alkanediyl, C_6-8Cycloalkanediyl group, C_6-14Alkanecycloalkanediyl and- [ (CHR)_p-X-]_q(CHR)_r-, where p, q, R, R and X are as for R¹The definitions are the same;

b represents a z-valent polyalkenyl polyfunctionalizing agent B (-R)⁷-CH＝CH₂)_zA core of, wherein

z may be an integer from 3 to 6; and is

Each R⁴Can be independently selected from C_1-10Alkanediyl, C_1-10Heteroalkanediyl, substituted C_1-10Alkanediyl and substituted C_1-10A heteroalkanediyl group.

In the moiety of formula (2) and the prepolymers of formulae (2a) and (2b), R¹May be C_2-10An alkanediyl group.

In the moiety of formula (2) and the prepolymers of formulae (2a) and (2b), R¹Can be- [ (CHR)_p-X-]_q(CHR)_r-。

In the moiety of formula (2) and the prepolymers of formulae (2a) and (2b), X may be selected from O and S, and thus- [ (CHR)_p-X-]_q(CHR)_rMay be- [ (CHR)_p-O-]_q(CHR)_r-or- [ (CHR)_p-S-]_q(CHR)_r-. P and r may be equal, for example where P and r may both be 2.

In the moiety of formula (2) and the prepolymers of formulae (2a) and (2b), R¹May be selected from C_2-6Alkanediyl and- [ (CHR)_p-X-]_q(CHR)_r-。

In the moiety of formula (2) and the prepolymers of formulae (2a) and (2b), R¹Can be- [ (CHR)_p-X-]_q(CHR)_rAnd X may be O, or X may be S.

In the moiety of formula (2) and the prepolymers of formulae (2a) and (2b), wherein R is¹Can be- [ (CHR)_p-X-]_q(CHR)_r-p can be 2, r can be 2, q can be 1, and X can be S; or p may be 2, q may be 2, r may be 2, and X may be O; or p may be 2, r may be 2, q may be 1, and X may be O.

In the moiety of formula (2) and the prepolymers of formulae (2a) and (2b), R¹Can be- [ (CHR)_p-X-]_q(CHR)_r-, each R may be hydrogen, or at least one R may be methyl.

In the moiety of formula (2) and formula(2a) In the prepolymer of (2a) and (2b), R¹May be- [ (CH)₂)_p-X-]_q(CH₂)_r-, wherein each X may be independently selected from O and S.

In the moiety of formula (2) and the prepolymers of formulae (2a) and (2b), R¹May be- [ (CH)₂)_p-X-]_q(CH₂)_r-, each X may be O or each X may be S.

In the moiety of formula 2) and the prepolymers of formulae (2a) and (2b), R¹May be- [ (CH)₂)_p-X-]_q(CH₂)_r-, where p may be 2, X may be O, q may be 2, R may be 2, R may be²May be ethanediyl, m may be 2, and n may be 9.

In the moiety of formula (2) and the prepolymers of formulae (2a) and (2b), each R is¹May be derived from 1, 8-dimercapto-3, 6-dioxaoctane (DMDO; 2,2- (ethane-1, 2-diylbis (sulfanyl)) bis (ethane-1-thiol)), or each R¹May be derived from dimercaptodiethylsulfide (DMDS; 2,2' -thiobis (ethane-1-thiol)), and combinations thereof.

In the moiety of formula (2) and the prepolymers of formulae (2a) and (2b), each p may be independently selected from 2,3, 4, 5 and 6. Each p may be the same and may be 2,3, 4, 5 or 6.

In the moiety of formula (2) and the prepolymers of formulae (2a) and (2b), each q may independently be 1,2,3, 4 or 5. Each q may be the same and may be 1,2,3, 4 or 5.

In the moiety of formula (2) and the prepolymers of formulae (2a) and (2b), each r may independently be 2,3, 4, 5,6, 7,8, 9, or 10. Each r may be the same and may be 2,3, 4, 5,6, 7,8, 9 or 10.

In the moiety of formula (2) and the prepolymers of formulae (2a) and (2b), each r may independently be an integer from 2 to 4, from 2 to 6, or from 2 to 8.

In the divinyl ether of formula (3), m may be an integer from 0 to 50, for example from 0 to 40, from 0 to 20, from 0 to 10, from 1 to 50, from 1 to 40, from 1 to 20, from 1 to 10, from 2 to 50, from 2 to 40, from 2 to 20 or from 2 to 10.

In the divinyl ether of the formula (3), each R²Can be independently selected from C_2-10N-alkanediyl radical, C_3-6Branched alkanediyl and- [ (CH)₂)_p-X-]_q(CH₂)_r-a group.

In the divinyl ether of the formula (3), each R²May independently be C_2-10N-alkanediyl radicals, such as methanediyl, ethanediyl, n-propanediyl or n-butanediyl.

In the divinyl ether of the formula (3), each R²May independently comprise- [ (CH)₂)_p-X-]_q(CH₂)_r-a group, wherein each X may be O or S.

In the divinyl ether of the formula (3), each R²May independently comprise- [ (CH)₂)_p-X-]_q(CH₂)_r-a group.

In the divinyl ether of formula (3), each m may independently be an integer of 1 to 3. Each m may be the same and may be 1,2 or 3.

In the divinyl ether of the formula (3), each R²Can be independently selected from C_2-10N-alkanediyl radical, C_3-6Branched alkanediyl and- [ (CH)₂)_p-X-]_q(CH₂)_r-a group.

In the divinyl ether of the formula (3), each R²May independently be C_2-10A n-alkanediyl group.

In the divinyl ether of the formula (3), each R²May independently be- [ (CH)₂)_p-X-]_q(CH₂)_r-a group, wherein each X may be O or S.

In the divinyl ether of the formula (3), each R²May independently be- [ (CH)₂)_p-X-]_q(CH₂)_r-a group, wherein each X may be O or S, and each p may independently be 2,3, 4, 5 and 6.

In the divinyl ether of formula (3), each p may be the same and may be 2,3, 4, 5 or 6.

In the divinyl ether of the formula (3), each R²May independently be- [ (CH)₂)_p-X-]_q(CH₂)_r-a group, wherein each X may be O or S, and each q may independently be 1,2,3, 4 or 5.

In the divinyl ether of formula (3), each q may be the same and may be 1,2,3, 4 or 5.

In the divinyl ether of the formula (3), each R²May independently be- [ (CH)₂)_p-X-]_q(CH₂)_r-a group, wherein each X may be O or S, and each r may independently be 2,3, 4, 5,6, 7,8, 9 or 10.

In the divinyl ether of formula (3), each r may be the same and may be 2,3, 4, 5,6, 7,8, 9 or 10. In the divinyl ether of formula (3), each r may independently be an integer from 2 to 4, from 2 to 6, or from 2 to 8.

Examples of suitable divinyl ethers include ethylene glycol divinyl ether (EG-DVE, butanediol divinyl ether (BD-DVE), hexanediol divinyl ether (HD-DVE), diethylene glycol divinyl ether (DEG-DVE), triethylene glycol divinyl ether, tetraethylene glycol divinyl ether, polytetrahydrofuranyl divinyl ether, cyclohexanedimethanol divinyl ether, and combinations of any of the foregoing.

The divinyl ether may include a sulfur-containing divinyl ether. Examples of suitable sulfur-containing divinyl ethers are disclosed in, for example, PCT publication No. WO 2018/085650.

In the moiety of formula (3), each a may be independently derived from a polyalkenyl polyfunctionalizing agent. The polyalkenyl polyfunctionalizing agent may have the structure of formula (4), wherein z may be 3,4, 5 or 6.

In the polyalkenyl polyfunctionalizing agent of formula (4), each R⁴Can be independently selected from C_1-10Alkanediyl, C_1-10Heteroalkanediyl, substituted C_1-10Alkanediyl or substituted C_1-10A heteroalkanediyl group. One or more substituent groups may be selected from, for example, -OH, ═ O, C_1-4Alkyl radicalAnd C_1-4An alkoxy group. The one or more heteroatoms may be selected from, for example, O, S and combinations thereof.

Examples of suitable polyalkenyl polyfunctionalizing agents include Triallylcyanurate (TAC), Triallylisocyanurate (TAIC), 1,3, 5-triallyl-1, 3, 5-triazinane-2, 4, 6-trione, 1, 3-bis (2-methylallyl) -6-methylene-5- (2-oxopropyl) -1,3, 5-triazinone-2, 4-dione, tris (allyloxy) methane, pentaerythritol triallylether, 1- (allyloxy) -2, 2-bis ((allyloxy) methyl) butane, 2-propane-2-ethoxy-1, 3, 5-tris (prop-2-enyl) benzene, 1,3, 5-tris (prop-2-enyl) -1,3, 5-triazinane-2, 4-dione and 1,3, 5-tris (2-methylallyl) -1,3, 5-triazinane-2, 4, 6-trione, 1,2, 4-trivinylcyclohexane, trimethylolpropane trivinyl ether and combinations of any of the foregoing.

In the moiety of formula (2) and the prepolymers of formulae (2a) - (2b), the molar ratio of the moiety derived from a divinyl ether to the moiety derived from a polyalkenyl polyfunctionalizing agent may be, for example, from 0.9 mol% to 0.999 mol%, from 0.95 mol% to 0.99 mol%, or from 0.96 mol% to 0.99 mol%.

In the moiety of formula (2) and the prepolymer of formulae (2a) - (2b), each R is¹May be- (CH)₂)₂-O-(CH₂)₂-O-(CH₂)₂-; each R²May be- (CH)₂)₂-; and m may be an integer of 1 to 4.

In the moiety of formula (2) and the prepolymers of formulae (2a) - (2b), R²May be derived from divinyl ethers such as diethylene glycol divinyl ether, polyalkenyl polyfunctionalizing agents such as triallylcyanurate, or combinations thereof.

In the moiety of formula (2) and the prepolymers of formulae (2a) - (2b), each a may be independently selected from the group consisting of a moiety of formula (3a) and a moiety of formula (4 a):

-(CH₂)₂-O-(R²-O)_m-(CH₂)₂- (3a)

B{-R⁴-(CH₂)₂-}₂{-R⁴-(CH₂)₂-S-[-R¹-S-A-S-R¹]_n-SH}_z-2 (4a)

wherein m and R¹、R²、R⁴A, B, m, n and z are as defined in formula (2), formula (3) and formula (4).

In the moiety of formula (3) and the prepolymers of formulae (2a) to (2b),

each R¹May be- (CH)₂)₂-O-(CH₂)₂-O-(CH₂)₂-; each R²May be- (CH)₂)₂-; m may be an integer of 1 to 4; and a polyfunctionalizing agent B (-R)⁴-CH＝CH₂)_zComprising triallyl cyanurate, wherein z is 3, and each R is⁴is-O-CH₂-CH＝CH₂。

Methods for synthesizing sulfur-containing polythioethers are disclosed, for example, in U.S. Pat. No. 6,172,179.

The backbone of the thiol-terminated polythioether prepolymer can be modified to improve properties, such as adhesion, tensile strength, elongation, UV resistance, hardness, and/or flexibility, of sealants and coatings prepared using polythioether prepolymers. For example, adhesion promoting groups, antioxidants, metal ligands, and/or urethane linkages may be incorporated into the backbone of the polythioether prepolymer to improve one or more performance attributes. Examples of backbone-modified polythioether prepolymers are disclosed in, for example, U.S. Pat. No. 8,138,273 (containing urethane), U.S. Pat. No. 9,540,540 (containing sulfone), U.S. Pat. No. 8,952,124 (containing bis (sulfonyl) alkanol), U.S. Pat. No. 9,382,642 (containing metal ligand), U.S. application publication No. 2017/0114208 (containing antioxidant), PCT International publication No. WO 2018/085650 (containing sulfur divinyl ether), and PCT International publication No. WO 2018/031532 (containing urethane). Polythioether prepolymers include those described in U.S. application publication Nos. 2017/0369737 and 2016/0090507.

Examples of suitable thiol-terminated polythioether prepolymers are disclosed, for example, in U.S. Pat. No. 6,172,179. The thiol-terminated polythioether prepolymer can includeP3.1E、P3.1E-2.8、L56086 or a combination of any of the foregoing, each of which is available from PPG Aerospace. TheseThe products are encompassed in thiol-terminated polythioether prepolymers of formulas (2), (2a), and (2 b). Thiol-terminated polythioethers include prepolymers described in U.S. patent No. 7,390,859 and urethane-containing polythiols described in U.S. application publication nos. 2017/0369757 and 2016/0090507.

The sulfur-containing prepolymer can include a polysulfide prepolymer or a combination of polysulfide prepolymers.

Polysulfide prepolymers are those containing one or more polysulfide linkages (i.e., -S) in the prepolymer backbone_x-a bond), wherein x is 2 to 4. The polysulfide prepolymer may have two or more sulfur-sulfur bonds. Suitable thiol-terminated polysulfide prepolymers are available under the trade names mercaptan-terminated polysulfideAndcommercially available from, for example, akzo nobel and Toray Industries, inc.

Examples of suitable polysulfide prepolymers are disclosed in, for example, U.S. patent nos. 4,623,711; nos. 6,172,179; U.S. Pat. No. 6,509,418; 7,009,032 No; and 7,879,955 th.

Examples of suitable thiol-terminated polysulfide prepolymers includeG polysulfides, e.g.G1、G4、G10、G12、G21、G22、G44、G122 andg131, commercially available from akzo nobel. Such asSuitable thiol-terminated polysulfide prepolymers, such as G resins, are liquid thiol-terminated polysulfide prepolymers that are blends of difunctional and trifunctional molecules, where the difunctional thiol-terminated polysulfide prepolymer has the structure of formula (5), and the trifunctional thiol-terminated polysulfide polymer may have the structure of formula (6):

HS-(R⁵-S-S-)_d-R⁵-SH (5)

HS-(R⁵-S-S-)_a-CH₂-CH{-CH₂-(S-S-R⁵-)_b-SH}{-(S-S-R⁵-)_c-SH} (6)

wherein each R⁵Is- (CH)₂)₂-O-CH₂-O-(CH₂)₂And d ═ a + b + c, where the value of d may be from 7 to 38, depending on the amount of trifunctional crosslinker (1,2, 3-trichloropropane; TCP) used during the synthesis of the polysulfide prepolymer.The G polysulfide may have a number average molecular weight of less than 1,000Da to 6,500Da, an SH content of 1% to more than 5.5%, and a crosslinking density of 0% to 2.0%.

The polysulfide prepolymer may further comprise a terminally modified polysulfide prepolymer having a structure of formula (5a), a terminally modified polysulfide prepolymer having a structure of formula (6a), or a combination thereof:

R³-S-(R⁵-S-S-)_d-R⁵-S-R³ (5a)

R³-S-(R⁵-S-S-)_a-CH₂-CH{-CH₂-(S-S-R⁵-)_b-S-}{-(S-S-R⁵-)_c-S-R³} (6a)

wherein d, a, b, c and R⁵As defined by formula (6) and formula (7), and R³Is a moiety that includes a terminal reactive group.

Examples of suitable thiol-terminated polysulfide prepolymers also include those available from Toray Industries, incLP polysulfides, e.g.LP2、LP3、Thiokol^TM LP12、LP23、LP33 andLP55。the LP polysulfide has a number average molecular weight of 1,000Da to 7,500Da, a-SH content of 0.8% to 7.7%, and a crosslinking density of 0% to 2%. Thiokol^TMThe LP polysulfide prepolymer has a structure of formula (7), and the end-modified polysulfide prepolymer may have a structure of formula (7 a):

HS-[(CH₂)₂-O-CH₂-O-(CH₂)₂-S-S-]_e-(CH₂)₂-O-CH₂-O-(CH₂)₂-SH (7)

R³-S-[(CH₂)₂-O-CH₂-O-(CH₂)₂-S-S-]_e-(CH₂)₂-O-CH₂-O-(CH₂)₂-S-R³ (7a)

wherein e may be such that the number average molecular weight is from 1,000Da to 7,500Da, such as an integer from 8 to 80, for example, and each R⁶Is a moiety that includes a terminal reactive functional group.

The thiol-terminated sulfur-containing prepolymer can includePolysulfide,G polysulfide, or a combination thereof.

The polysulfide prepolymer may comprise a polysulfide prepolymer comprising moieties of formula (7), a thiol-terminated polysulfide prepolymer of formula (7a), a terminally modified polysulfide prepolymer of formula (7b), or a combination of any of the foregoing:

-R⁶-(S_y-R⁶)_t- (7)

HS-R⁶-(S_y-R⁶)_t-SH (7a)

R³-S-R⁶-(S_y-R⁶)_t-S-R³ (7b)

wherein

t may be an integer from 1 to 60;

y may have an average value in the range of 1.0 to 1.5;

each R may be independently selected from branched alkanediyl, branched arenediyl, and having the structure- (CH)₂)_p–O–(CH₂)_q–O–(CH₂)_rA moiety of (a) wherein

q may be an integer from 1 to 8;

p may be an integer from 1 to 10; and is

r may be an integer from 1 to 10; and is

Each R³Is a moiety that includes a terminal reactive functional group.

In the moiety of formula (7) and the prepolymer of formulae (7a) - (7b), 0% to 20% of R⁶The group may include a branched alkanediyl or branched arenediyl group, and 80% to 100% of R⁶The radical may be- (CH)₂)_p–O–(CH₂)_q–O–(CH₂)_r–。

In the moiety of formula (7) and the prepolymers of formulae (7a) - (7b), the branched alkanediyl or branched arenediyl may be-R (-A)_f-, wherein R is a hydrocarbon group, f is 1 or 2, and a is a branch point. The branched alkanediyl group may have the structure-CH₂(–CH(–CH₂–)–)–。

Examples of thiol-terminated polysulfide prepolymers of the formulae (7a) and (7b) are disclosed, for example, in U.S. application publication No. 2016/0152775, U.S. patent No. 9,079,833, and U.S. patent No. 9,663,619.

The sulfur-containing prepolymer may comprise a sulfur-containing polyformal prepolymer or a combination of sulfur-containing polyformal prepolymers. Sulfur-containing polyformal prepolymers useful in sealant applications are disclosed, for example, in U.S. patent No. 8,729,216 and U.S. patent No. 8,541,513.

The polysulfide prepolymer can include a polysulfide prepolymer comprising moieties of formula (8), a thiol-terminated polysulfide prepolymer of formula (8a), a terminally modified polysulfide prepolymer of formula (8b), or a combination of any of the foregoing:

-(R⁷-O-CH₂-O-R⁷-S_s-)_g-1-R⁷-O-CH₂-O-R⁷- (8)

HS-(R⁷-O-CH₂-O-R-S_s-)_g-1-R⁷-O-CH₂-O-R⁷-SH (8a)

R³-S-(R⁷-O-CH₂-O-R⁷-S_s-)_g-1-R⁷-O-CH₂-O-R⁷-S-R³ (8b)

wherein R is⁷Is C_2-4Alkanediyl, s is an integer from 1 to 8, and g is an integer from 2 to 370; and each R³Independently a moiety comprising a terminal reactive functional group.

The moiety of formula (8) and the prepolymers of formulae (8a) to (8b) are disclosed in, for example, JP 62-53354.

The sulfur-containing polyformal prepolymer may comprise a moiety of formula (9), a thiol-terminated sulfur-containing polyformal prepolymer of formula (9a), a terminal-modified sulfur-containing polyformal prepolymer of formula (9b), a thiol-terminated sulfur-containing polyformal prepolymer of formula (9c), a terminal-modified sulfur-containing polyformal prepolymer of formula (9d), or a combination of any of the foregoing:

-R⁸-(S)_p-R⁸-[O-C(R⁹)₂-O-R⁸-(S)_v-R⁸-]_h- (9)

R¹⁰-R⁸-(S)_p-R⁸-[O-C(R⁹)₂-O-R⁸-(S)_v-R⁸-]_h-R¹⁰ (9a)

R³-R⁸-(S)_p-R⁸-[O-C(R⁹)₂-O-R⁸-(S)_v-R⁸-]_h-R³ (9b)

{R¹⁰-R⁸-(S)_p-R⁸-[O-C(R⁹)₂-O-R⁸-(S)_v-R⁸-]_h-O-C(R⁹)₂-O-}_mZ (9c)

{R³-R⁸-(S)_p-R⁸-[O-C(R⁹)₂-O-R⁸-(S)_v-R⁸-]_h-O-C(R⁹)₂-O-}_mZ (9d)

wherein h can be an integer from 1 to 50; each v may be independently selected from 1 and 2; each R⁸May be C_2-6An alkanediyl group; and each R⁹Can be independently selected from hydrogen and C_1-6Alkyl radical, C_7-12Phenylalkyl, substituted C_7-12Phenylalkyl, C_6-12Cycloalkylalkyl, substituted C_6-12Cycloalkylalkyl radical, C_3-12Cycloalkyl, substituted C_3-12Cycloalkyl radical, C_6-12Aryl and substituted C_6-12An aryl group; each R¹⁰Is a moiety comprising a terminal thiol group; and each R³Independently a moiety comprising a terminal reactive functional group other than a thiol group; and Z may be derived from an m-valent parent polyol Z (OH)_mThe core of (1).

The sulfur-containing prepolymer may include a monosulfide prepolymer or a combination of monosulfide prepolymers.

The monosulfide prepolymer can include moieties of formula (10), a thiol-terminated monosulfide prepolymer of formula (10a), a thiol-terminated monosulfide prepolymer of formula (10b), a terminal-modified monosulfide prepolymer of formula (10c), a terminal-modified monosulfide prepolymer of formula (10d), or a combination of any of the foregoing:

-S-R¹³-[S-(R¹¹-X)_w-(R¹²-X)_u-R¹³-]_x-S- (10)

HS-R¹³-[S-(R¹¹-X)_w-(R¹²-X)_u-R¹³-]_x-SH (10a)

{HS-R¹³-[S-(R¹¹-X)_w-(R¹²-X)_u-R¹³-]_x-S-V'-}_zB (10b)

R³-S-R¹³-[S-(R¹¹-X)_w-(R¹²-X)_u-R¹³-]_x-S-R³ (10c)

{R³-S-R¹³-[S-(R¹¹-X)_w-(R¹²-X)_u-R¹³-]_x-S-V'-}_zB (10d)

wherein

Each R¹¹Can be independently selected from C_2-10Alkanediyl, e.g. C_2-6An alkanediyl group; c_2-10Branched alkanediyl, e.g. C_3-6Branched alkanediyl or C having one or more side groups_3-6A branched alkanediyl group, which side group may be, for example, an alkyl group, such as a methyl or ethyl group; c_6-8A cycloalkanediyl group; c_6-14Alkylcycloalkanediyl radicals, e.g. C_6-10An alkylcycloalkanediyl group; and C_8-10An alkylaromatic diyl group;

each R¹²Can be independently selected from hydrogen and C_1-10N-alkanediyl, e.g. C_1-6N-alkanediyl, C_2-10Branched alkanediyl, e.g. C, having one or more side groups_3-6A branched alkanediyl group, which side group may be, for example, an alkyl group, such as a methyl or ethyl group; c_6-8A cycloalkanediyl group; c_6-14Alkylcycloalkanediyl radicals, e.g. C_6-10An alkylcycloalkanediyl group; and C_8-10An alkylaromatic diyl group;

each R¹³Can be independently selected from hydrogen and C_1-10N-alkanediyl, e.g. C_1-6N-alkanediyl, C_2-10Branched alkanediyl, e.g. C, having one or more side groups_3-6A branched alkanediyl group, which side group may be, for example, an alkyl group, such as a methyl or ethyl group; c_6-8A cycloalkanediyl group;C_6-14alkylcycloalkanediyl radicals, e.g. C_6-10An alkylcycloalkanediyl group; and C_8-10An alkylaromatic diyl group;

each X may be independently selected from O and S;

w may be an integer from 1 to 5;

u may be an integer of 0 to 5; and is

x may be an integer from 1 to 60, such as from 2 to 60, from 3 to 60, or from 25 to 35;

each R³Independently selected from reactive functional groups;

b represents a z-valent polyfunctionalizing agent B (-V)_zThe core of (1), wherein:

z may be an integer from 3 to 6; and is

Each V may be a moiety comprising an end group reactive with a thiol group;

each-V' -may be derived from the reaction of-V with a thiol.

Methods for synthesizing thiol-terminated monosulfides comprising moieties of formula (10) or prepolymers of formulae (10b) - (10c) are disclosed, for example, in U.S. patent No. 7,875,666.

The monosulfide prepolymer can include moieties of formula (11), a thiol-terminated monosulfide prepolymer that includes moieties of formula (11a), a thiol-terminated monosulfide prepolymer that includes a thiol-terminated monosulfide prepolymer of formula (11b), a thiol-terminated monosulfide prepolymer of formula (11c), a thiol-terminated monosulfide prepolymer of formula (11d), or a combination of any of the foregoing:

-[S-(R¹⁴-X)_w-C(R¹⁵)₂-(X-R¹⁴)_q-]_x-S- (11)

H-[S-(R¹⁴-X)_w-C(R¹⁵)₂-(X-R¹⁴)_u-]_x-SH (11a)

R³-[-S-(R¹⁴-X)_w-C(R¹⁵)₂-(X-R¹⁴)_u-]_x-S-R³ (11b)

{H-[S-(R¹⁴-X)_w-C(R¹⁵)₂-(X-R¹⁴)_u-]_x-S-V'-}_zB (11c)

{R³-[S-(R¹⁴-X)_w-C(R¹⁵)₂-(X-R¹⁴)_u-]_x-S-V'-}_zB (11d)

wherein

Each R¹⁴Can be independently selected from C_2-10Alkanediyl, e.g. C_2-6An alkanediyl group; c_3-10Branched alkanediyl, e.g. C_3-6Branched alkanediyl or C having one or more side groups_3-6A branched alkanediyl group, which side group may be, for example, an alkyl group, such as a methyl or ethyl group; c_6-8A cycloalkanediyl group; c_6-14Alkylcycloalkanediyl radicals, e.g. C_6-10An alkylcycloalkanediyl group; and C_8-10An alkylaromatic diyl group;

each R¹⁵Can be independently selected from hydrogen and C_1-10N-alkanediyl, e.g. C_1-6N-alkanediyl, C_3-10Branched alkanediyl, e.g. C, having one or more side groups_3-6A branched alkanediyl group, which side group may be, for example, an alkyl group, such as a methyl or ethyl group; c_6-8A cycloalkanediyl group; c_6-14Alkylcycloalkanediyl radicals, e.g. C_6-10An alkylcycloalkanediyl group; and C_8-10An alkylaromatic diyl group;

each X may be independently selected from O and S;

w may be an integer from 1 to 5;

u may be an integer of 1 to 5;

x may be an integer from 1 to 60, such as from 2 to 60, from 3 to 60, or from 25 to 35;

each R³Is a moiety comprising a terminal functional group;

b represents a z-valent polyfunctionalizing agent B (-V)_zThe core of (1), wherein:

z may be an integer from 3 to 6; and is

Each V may be a moiety comprising an end group reactive with a thiol group;

each-V' -may be derived from the reaction of-V with a thiol.

Methods for synthesizing the monosulfides of formulas (11) to (11d) are disclosed, for example, in U.S. patent No. 8,466,220.

The co-reactive composition may include a co-reactive compound having any suitable co-reactive functional group.

The first co-reactive compound may include one or more first functional groups and the second co-reactive compound may include one or more second functional groups, wherein the one or more first functional groups may react with the one or more second functional groups.

The functional group or combination of functional groups may be selected to achieve, for example, a desired cure rate. For example, for ease of handling, it may be desirable for the outer portion of the sealing cap to have a fast cure rate to facilitate handling. Other portions of the seal may have a slow cure rate to allow for the formation of surface bonds, bonds between co-reactive compositions, and/or desired physical properties.

For example, the first functional group can include a thiol group, and the second functional group can include a thiol group, an alkenyl group, an alkynyl group, an epoxy group, a michael acceptor group, an isocyanate group, or a combination of any of the foregoing.

The first functional group may include, for example, an isocyanate, and the second functional group may include a hydroxyl group, an amine group, a thiol group, or a combination of any of the foregoing.

The first functional group may include, for example, an epoxy group, and the second functional group may include an epoxy group.

The first functional group may include, for example, a michael acceptor group, and the second functional group may include a michael donor group.

The first functional group may comprise, for example, a carboxylic acid group, and the second functional group may comprise an epoxy group.

The first functional group may include, for example, a cyclic carbonate group, an acetoacetate group, or an epoxy group; and the second functional group may include a primary amine group or a secondary amine group.

The first functional group may include michael acceptor groups, such as (meth) acrylate groups, cyanoacrylates, vinyl ethers, vinylpyridines, or α, β -unsaturated carbonyl groups, and the second functional group may include malonate groups, acetylacetonate groups, nitroalkanes, or other active alkenyl groups.

The first functional group may include an amine, and the second functional group may include a functional group selected from an epoxy group, an isocyanate group, acrylonitrile, a carboxylic acid (including esters and anhydrides), an aldehyde, or a ketone.

Suitable co-reactive functional groups are described, for example, in Noomen, Proceedings of the thirteenth International Conference on Organic coating Science and Technology (Proceedings of the XIIth International Conference on Organic Coatings Science and Technology), Athens, 1987, p 251; and Tillet et al, Progress in Polymer Science, 36(2011), 191-217.

The functional groups can be selected to co-react at temperatures, for example, of less than 50 ℃, less than 40 ℃, less than 30 ℃, less than 20 ℃, or less than 10 ℃. The functional groups can be selected to co-react at temperatures, for example, greater than 5 ℃, greater than 10 ℃, greater than 20 ℃, greater than 30 ℃, or greater than 40 ℃. The functional groups may be selected to co-react at temperatures of, for example, 5 ℃ to 50 ℃,10 ℃ to 40 ℃, 15 ℃ to 35 ℃, or 20 ℃ to 30 ℃.

The cure rate of any of these co-reactive chemistries can be varied by including a suitable catalyst or combination of catalysts in the co-reactive composition. The cure rate of any of these co-reactive chemistries can be altered by increasing or decreasing the temperature of the co-reactive composition. For example, although the co-reactive composition may be cured at a temperature of less than 30 ℃, heating the co-reactive composition may increase the reaction rate, which may be desirable in certain circumstances, for example, to accommodate increased printing speeds. Increasing the temperature of the coreactive components and/or coreactive compositions can also be used to adjust the viscosity to facilitate mixing of the coreactive components and/or deposition of the coreactive compositions.

The co-reactive composition may include a co-reactive compound capable of co-reacting at a temperature of less than 50 ℃ without exposure to actinic radiation and may optionally include a catalyst.

For example, a co-reactive composition may include compounds such as monomers and/or prepolymers that include co-reactive functional groups including, for example, any of those disclosed herein.

The co-reactive composition may further comprise a suitable catalyst or combination of catalysts for catalyzing the reaction between the co-reactive compounds.

The co-reactive composition can be an actinic radiation curable co-reactive composition in which the curing reaction between the co-reactive compounds in the co-reactive composition is initiated by exposure of the co-reactive composition to actinic radiation.

Actinic radiation includes alpha-rays, gamma-rays, X-rays, Ultraviolet (UV) radiation (200nm to 400nm), such as UV-A radiation (320nm to 400nm), UV-B radiation (280nm to 320nm), and UV-C radiation (200nm to 280 nm); visible radiation (400nm to 770nm), radiation in the blue wavelength range (450nm to 490nm), infrared radiation (>700nm), near infrared radiation (0.75 μm to 1.4 μm) and electron beams.

The radiation curable co-reactive composition may include compounds capable of co-reacting by a free radical mechanism. Examples of free radical curing reactions include thiol/alkenyl reactions and thiol/alkynyl reactions.

The radiation curable co-reactive composition may include any suitable free radical polymerization initiator or combination of suitable free radical polymerization initiators. Examples of the radical polymerization initiator include a photoinitiator, a thermally activated radical generator, a cationic radical generator, and a dark curing radical generator.

The radiation curable co-reactive composition may include a photoinitiator, such as a visible photoinitiator or a UV photoinitiator.

The radiation curable co-reactive composition may include a thermally activated free radical generator.

The radiation curable co-reactive composition may include a cationic free radical generator.

The radiation curable co-reactive composition may include a dark curing free radical generator.

The free radical photopolymerization reaction may be initiated by exposing the co-reactive composition to actinic radiation, e.g., UV radiation, for example, for less than 180 seconds, less than 120 seconds, less than 90 seconds, less than 60 seconds, less than 30 seconds, less than 15 seconds, or less than 5 seconds. The total power of the UV exposure may be, for example, 50mW/cm²To 500mW/cm²、50mW/cm²To 400mW/cm²、50mW/cm²To 300mW/cm²、100mW/cm²To 300mW/cm²Or 150mW/cm²To 250mW/cm²。

Actinic radiation curable coreactive compositions can be exposed to 1J/cm²To 4J/cm²To cure the composition. The UV source is an 8W lamp with UVA spectrum. Other doses and/or other UV sources may be used. The UV dose used to cure the composition may be, for example, 0.5J/cm²To 4J/cm²、0.5J/cm²To 3J/cm²、1J/cm²To 2J/cm²Or 1J/cm²To 1.5J/cm²。

Actinic radiation-curable co-reactive compositions can also be cured with radiation in the blue wavelength range, for example using light emitting diodes.

Examples of actinic radiation curable sealant compositions suitable for sealing caps are disclosed in, for example, U.S. patent nos. 8,729,198; U.S. patent No. 8,729,198; U.S. patent No. 9,533,798; U.S. patent No. 10,233,369; U.S. application publication No. 2019/0169465; PCT International publication No. PCT/US 2018/36746; U.S. application publication No. 2018/0215974; and in U.S. patent No. 7,438,974.

The free radically polymerizable co-reactive composition can transmit actinic radiation such that incident actinic radiation can generate sufficient free radicals to allow the free radically polymerizable co-reactive composition to fully cure.

For example, an actinic radiation transmissive co-reactive composition can transmit actinic radiation through a thickness of the co-reactive composition, such as 1mm to 30mm, 1mm to 25mm, 1mm to 20mm, 1mm to 15mm, or 1mm to 10 mm.

The radically polymerizable co-reactive composition can be partially transmissive to actinic radiation such that incident actinic radiation can generate sufficient radicals to initiate free radical polymerization of the co-reactive composition in at least a portion of the exposed co-reactive composition. The unexposed portions of the co-reactive composition may be cured by another free radical mechanism, such as a dark cure mechanism, or may be cured by a non-free radical mechanism.

The free radical initiation wavelength range may depend on the type of free radical generator in the co-reactive composition.

The first coreactive composition may have the same cure rate as the second coreactive composition or may have a different cure rate than the second coreactive composition. For example, for ease of handling, a first coreactive composition used to make a closure shell may have a faster cure rate than a second coreactive composition. The cure rate of the co-reactive composition may be selected to enhance one or more properties of the inner and outer portions of the sealing cap.

Using co-reactive three-dimensional printing, co-reactive compositions can be deposited, for example, at a speed of 1 mm/sec to 400 mm/sec and/or a flow rate of 0.1 mL/min to 20,000 mL/min.

The first and second coreactive compositions can be the same or different. For example, different co-reactive compositions may include differences in the types and amounts of ingredients, which may result in different portions of the sealing cap having different properties. For example, the co-reactive composition used to form the seal cap may include reactants, catalysts, adhesion promoters, fillers, reactive diluents, colorants, rheology control agents, and/or photochromic agents, which may be the same or different or present in a different wt% or vol% from another layer of the multilayer seal cap. The co-reactive compositions may also include the same or different curing chemistries.

A coreactive composition capable of curing without exposure to actinic radiation can be deposited and cured, and the curing rate will be determined by, for example, the curing chemistry, the type and amount of catalyst, the temperature, and the viscosity of the deposited coreactive composition. After deposition, the coreactive composition can be exposed to heat to accelerate the curing of at least a portion of the coreactive composition.

Curing of the free-radically polymerizable co-reactive composition may be initiated by activating the free-radical generator, for example, by exposing the free-radically polymerizable co-reactive composition to actinic radiation or heat.

For example, the free radically polymerizable co-reactive composition can be exposed to actinic radiation while the free radically polymerizable co-reactive composition is in the three-dimensional printing apparatus, during deposition of the free radically polymerizable co-reactive composition, and/or after the free radically polymerizable co-reactive composition has been deposited. The deposited free radically polymerizable co-reactive composition may be exposed to actinic radiation, for example, after the initial deposition of the co-reactive composition or, depending on the method of manufacture, after the fabrication of the sealing cap shell, after the application of a continuous layer thereto as a fastener to form the sealing cap, or after the application of the sealing cap to the fastener.

The seal cap shell can be fabricated using an actinic radiation curable co-reactive composition, and/or the interior volume can include an actinic radiation curable co-reactive composition. The seal cap shell and sealant filling the interior volume can include a co-reactive composition that is not curable using actinic radiation. The shell can include an actinic radiation curable composition and the sealant filling the interior volume can include a non-actinic radiation curable co-reactive composition. The shell of the sealing cap can include an actinic radiation-curable co-reactive composition, and the sealant that fills the interior volume can include an actinic radiation-curable co-reactive composition.

The hermetic cap shell can be fabricated by depositing successive layers of actinic radiation curable co-reactive composition using three-dimensional printing.

The shell can also be exposed to actinic radiation after fabrication and prior to filling the internal volume with the actinic radiation curable co-reactive composition to partially cure the shell or to fully cure the shell. The shell may be at least partially cured to provide a retainer for the inner composition and to facilitate the ability to handle and assemble the sealing cap over the fastener.

When the shell is built, the physical properties of the co-reactive composition may be such that the deposited co-reactive composition retains its intended shape and has sufficient mechanical strength to support the upper layer of co-reactive composition before the lower layer is fully cured. The physical properties may be determined in part by the amount of ingredients in the composition, the type and rate of cure, and the like.

The sealing cap can be manufactured by printing a co-reactive composition that does not require exposure to actinic radiation to initiate a chemical reaction. The shell can be fabricated using three-dimensional printing to deposit successive layers of a co-reactive composition to form a sealed cap shell, and the internal volume can be filled with the same or different co-reactive compositions. Procedures similar to those described for making actinic radiation curable sealing caps are applicable except that the co-reactive composition is exposed to actinic radiation.

The shell may be at least partially cured while the second coreactive composition is deposited within the interior volume. For example, the shell can have a non-stick surface or have a hardness of, for example, greater than shore 5A or greater than shore 10A, when the second coreactive composition is deposited within the interior volume. The second coreactive composition has a compound that can react with the compound in the first coreactive composition to form a chemical bond, and only partial curing of the shell may be desired. Chemical bonding between the shell and the internal sealant can improve the integrity of the interface and the bond strength. The coreactive compositions of adjacent layers may chemically and/or physically interact to form strong interlayer bonds. The interaction may be through chemical bonding and/or physical entanglement between adjacent layers.

An optional intermediate layer may be applied to the inner surface of the shell after the shell is manufactured and before the inner volume is filled. The intermediate layer can be used to promote adhesion between the shell and the second coreactive composition, promote chemical bonding between the shell and the second coreactive composition, and/or can be used to enhance properties such as chemical resistance. The intermediate layer may have a thickness of, for example, 0.05mm to 3mm, for example, 0.1mm to 2 mm. The intermediate layer may be applied to the inner surface of the shell after the shell is fabricated, or may be applied to the extruded first and/or second co-reactive compositions as the extrudate is deposited by the three-dimensional printing apparatus. For example, the adhesion promoting layer can be co-extruded with the extruded co-reactive composition, or the adhesion promoting layer can be applied to the extrudate by contacting at least a portion of the extrudate with the adhesion promoting composition before the extrudate is deposited onto the substrate or underlying layer of deposited co-reactive composition.

After the shell has been fabricated, the interior volume defined by the shell can be at least partially filled with a second co-reactive composition. The amount of the second coreactive composition deposited within the interior volume can be selected to minimize the amount of the second coreactive composition that is removed from the sealing cap when the sealing cap is assembled onto the fastener. At the same time, the amount of the second coreactive composition within the interior volume may be sufficient to facilitate the ability of the second coreactive composition to fully conform to the geometry of the fastener and minimize the presence of voids when the sealing cap is assembled over the fastener.

As with the first coreactive composition, the second coreactive composition can comprise a single part coreactive composition or a multi-part composition deposited into the interior volume using three-dimensional printing (wherein two or more ingredients of the actinic radiation curable coreactive composition are combined in a mixer at the time of use and extruded into the interior volume through a nozzle using three-dimensional printing equipment). The method of filling the interior volume with the second actinic radiation-curable composition can be designed to avoid entrapped voids and air pockets.

After the interior volume of the shell is filled with the second co-reactive composition, and before the second co-reactive composition cures, a sealing cap may be assembled thereover as a fastener. It is desirable that the outer surface of the shell has cured while the sealing cap is assembled over the fastener so that the sealing cap can be manually or automatically manipulated. For example, the shell may have a non-stick surface. For example, the shell can have sufficient mechanical strength that it can be picked up and placed onto the fastener with sufficient force so that the second co-reactive composition can conform to the geometry of the fastener to remove air pockets and minimize voids. Upon assembly of the sealing cap over the fastener, the second coreactive composition may have a viscosity such that the second coreactive composition remains within the interior volume such that the second coreactive composition does not flow out from under the base of the sealing cap to an appreciable extent when the sealing cap is manipulated over the fastener. In addition, the second coreactive composition may have a sufficiently low viscosity such that it conforms to the fastener and other elements of the part being sealed.

Any suitable photoinitiator may be used, for example a thermally activated free radical initiator, or a free radical initiator activated by actinic radiation, or a photoinitiator, and the like.

The photoinitiator may be activated by actinic radiation, which may apply energy, effective to generate initiating species upon irradiation, such as alpha-rays, gamma-rays, X-rays, Ultraviolet (UV) light, including UVA, and UVC spectra), visible light, blue light, infrared, near-infrared, or electron beams, from the photopolymerization initiator. For example, the photoinitiator may be a UV photoinitiator.

Examples of suitable UV photoinitiators include alpha-hydroxyketone, benzophenone, alpha-diethoxyacetophenone, 4-diethylaminobenzophenone, 2-dimethoxy-2-phenylacetophenone, 4-isopropylphenyl-2-hydroxy-2-propyl ketone, 1-hydroxycyclohexyl phenyl ketone, isoamyl p-dimethylaminobenzoate, methyl 4-dimethylaminobenzoate, methyl O-benzoylbenzoate, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-isopropylthioxanthone, dibenzosuberone, 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, bis-phosphine oxide, Benzophenone photoinitiators, oxime photoinitiators, phosphine oxide photoinitiators, and combinations of any of the foregoing.

The thermally activated free radical initiator may become active at elevated temperatures, for example at temperatures above 25 ℃. Examples of suitable thermally activated free radical initiators include organic peroxy compounds, azobis (organonitrile) compounds, N-acyloxyamine compounds, O-imino-isourea compounds, and combinations of any of the foregoing. Examples of suitable organic peroxy compounds which may be used as thermal polymerization initiators include peroxymonocarbonates such as t-butylperoxy 2-ethylhexyl carbonate and t-butylperoxyisopropyl carbonate; peroxyketals, such as 1, 1-di- (tert-butylperoxy) -3,3, 5-trimethylcyclohexane; peroxydicarbonates such as di (2-ethylhexyl) peroxydicarbonate, di (sec-butyl) peroxydicarbonate and diisopropylperoxydicarbonate; diacyl peroxides, such as 2, 4-dichlorobenzoyl peroxide, isobutyryl peroxide, decanoyl peroxide, lauroyl peroxide, propionyl peroxide, acetyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide; peroxyesters such as t-butyl peroxypivalate, t-butyl peroxyoctanoate, and t-butyl peroxyisobutyrate; methyl ethyl ketone peroxide, acetyl cyclohexane sulfonyl peroxide, and combinations of any of the foregoing. Other examples of suitable thermal polymerization initiators include 2, 5-dimethyl-2, 5-di (2-ethylhexanoylperoxide) hexane and/or 1, 1-bis (t-butylperoxy) -3,3, 5-trimethylcyclohexane. Examples of suitable azobis (organonitrile) compounds that may be used as thermal polymerization initiators include azobis (isobutyronitrile), 2' -azobis (2-methyl-butyronitrile), and/or azobis (2/1-dimethylvaleronitrile).

The coreactive composition may have a tack free time of less than 8 hours, less than 6 hours, less than 4 hours, less than 2 hours, less than 1 hour, or less than 30 minutes at 25C/50% RH, where the tack free time is determined according to AS5127/1(5.8) (aerospace standard test method for aerospace sealants).

The co-reactive composition used to form the sealing cap exhibiting a fast shore 10A hardness time may include, for example, co-reactants having fast cure chemistry, systems curable by actinic radiation, catalysts, and combinations of any of the foregoing.

The fast shore 10A hardness time of the cured composition may be less than 10 minutes, wherein the hardness is determined according to ISO 868 at 23 ℃/55% RH.

The co-reactive composition used to form the sealing cap with electrical conductivity, EMI/RFI shielding and/or static dissipation can include, for example, a conductive filler or a combination of conductive fillers.

The co-reactive composition may be substantially free of solvent. For example, the coreactive composition can have less than 5 wt%, less than 2 wt%, less than 1 wt%, less than 0.5 wt%, or less than 0.1 wt% of solvent, where wt% is based on the total weight of the coreactive composition.

The co-reactive composition may include, for example, one or more additives such as, for example, catalysts, polymerization initiators, adhesion promoters, reactive diluents, plasticizers, fillers, colorants, photochromic agents, rheology modifiers, reactive diluents, cure activators and accelerators, corrosion inhibitors, flame retardants, UV stabilizers, rain erosion inhibitors, or a combination of any of the foregoing.

The co-reactive composition may include a catalyst or combination of catalysts, where one or more catalysts are selected to catalyze a reaction between co-reactants in the co-reactive composition, such as a first co-reactive compound and a second co-reactive compound.

The catalyst or combination of catalysts may be selected to catalyze the reaction of the co-reactants in the co-reactive composition, such as the reaction of the first compound and the second compound. Suitable catalysts will depend on the curing chemistry. For example, the thiol-ene or thiol epoxide may include an amine catalyst.

The co-reactive composition can include, for example, 0.1 wt% to 1 wt%, 0.2 wt% to 0.9 wt%, 0.3 wt% to 0.7 wt%, or 0.4 wt% to 0.6 wt% of a catalyst or combination of catalysts, where wt% is based on the total weight of the co-reactive composition.

The catalyst may comprise a latent catalyst or a combination of latent catalysts. Latent catalysts comprise catalysts that have little or no activity prior to being released or activated, for example by physical and/or chemical mechanisms. The latent catalyst may be contained within the structure or may be chemically blocked. The controlled release catalyst may release the catalyst upon exposure to ultraviolet radiation, heat, sonication, or moisture. The latent catalyst may be isolated within a core-shell structure or entrapped within a matrix of a crystalline or semi-crystalline polymer, wherein the catalyst may diffuse from the encapsulant over time or upon activation, such as by application of thermal or mechanical energy.

The co-reactive composition may include a dark cure catalyst or a combination of dark cure catalysts. Dark cure catalysts are catalysts that are capable of generating free radicals without exposure to electromagnetic energy.

Dark cure catalysts comprise, for example, a combination of a metal complex and an organic peroxide, a trialkylborane complex, and a peroxide-amine redox initiator. The dark curing catalyst may be used in combination with the photopolymerization initiator or independently of the photopolymerization initiator.

Co-reactive compositions based on thiol/thiol curing chemistry may include a curing activator or combination of curing activators to initiate thiol/thiol polymerization reactions. The curing activator can be used, for example, in a co-reactive composition, where the first compound and the second compound comprise a thiol-terminated sulfur-containing prepolymer, such as a thiol-terminated polysulfide prepolymer.

The curing activator may include an oxidizing agent capable of oxidizing the thiol groups to form disulfide bonds. Examples of suitable oxidizing agents include lead dioxide, manganese dioxide, calcium dioxide, sodium perborate monohydrate, calcium peroxide, zinc peroxide, and dichromate.

The curing activator may comprise an inorganic activator, an organic activator, or a combination thereof.

Examples of suitable inorganic activators include metal oxides. Examples of suitable metal oxide activators include zinc oxide (ZnO), lead oxide (PbO), lead peroxide (PbO)₃) Manganese dioxide (MnO)₂) Sodium perborate (NaBO)₃·H₂O), potassium permanganate (KMnO)₄) Calcium peroxide (CaCO)₃) Barium peroxide (BaO)₃) Cumene hydroperoxide and combinations of any of the foregoing. The curing activator may be MnO₂。

The co-reactive composition based on thiol/thiol curing chemistry may include, for example, 1 wt% to 10 wt% of a curing activator or combination of curing activators, where wt% is by total weight of the composition. For example, a co-reactive composition can include 1 wt% to 9 wt%, 2 wt% to 8 wt%, 3 wt% to 7 wt%, or 4 wt% to 6 wt% of an activator or combination of curing activators, where wt% is by total weight of the composition. For example, a co-reactive composition may include greater than 1 wt% of a curing activator or combination of curing activators, greater than 2 wt%, greater than 3 wt%, greater than 4 wt%, greater than 5 wt%, or greater than 6 wt% of a curing activator or combination of curing activators, where wt% is by total weight of the composition.

Co-reactive compositions based on thiol/thiol curing chemistry may include a cure accelerator or a combination of cure accelerators.

The cure accelerator can act as a sulfur donor to generate active sulfur fragments capable of reacting with the thiol groups of the thiol-terminated polysulfide prepolymer.

Examples of suitable cure accelerators include thiazoles, thiurams, sulfenamides, guanidines, dithiocarbamates, xanthates, thioureas, aldamines, and combinations of any of the foregoing.

The cure accelerator can be a thiuram polysulfide, a thiuram disulfide, or a combination thereof.

Examples of other suitable cure accelerators also include triazine and sulfide or metal and amine salts of dialkyldithiophosphoric acids and dithiophosphoric acid esters, such as triazine and sulfide or metal and amine salts of dialkyldithiophosphoric acids, and combinations of any of the foregoing. Examples of non-sulfur containing cure accelerators include Tetramethylguanidine (TMG), di-o-tolylguanidine (DOTG), sodium hydroxide (NaOH), water, and a base.

The co-reactive composition may include, for example, 0.01 wt% to 2 wt% of a cure accelerator or combination of cure accelerators, 0.05 wt% to 1.8 wt%, 0.1 wt% to 1.6 wt%, or 0.5 wt% to 1.5 wt% of a cure accelerator or combination of cure accelerators, where wt% is by total weight of the composition. The co-reactive composition can include, for example, less than 2 wt%, less than 1.8 wt%, less than 1.6 wt%, less than 1.4 wt%, less than 1.2 wt%, less than 1 wt%, less than 0.5 wt%, less than 0.1 wt%, or less than 0.05 wt% of a curing promoter or combination of curing promoters, where wt% is based on the total weight of the composition.

The co-reactive composition may include an adhesion promoter or a combination of adhesion promoters. The adhesion promoter may enhance the adhesion of the coreactive composition to an underlying substrate such as a metal, composite, polymer or ceramic surface or to a coating such as a primer coating or other coating. The adhesion promoter may enhance adhesion to the filler and to other layers of the sealing cap.

The adhesion promoter may comprise a phenolic adhesion promoter, a combination of phenolic adhesion promoters, an organofunctional silane, a combination of organofunctional silanes, or a combination of any of the foregoing. The organofunctional alkoxysilane may be an amine functional alkoxysilane. The organic group may be selected from, for example, a thiol group, an amine group, a hydroxyl group, an epoxy group, an alkynyl group, an alkenyl group, an isocyanate group, or a michael acceptor group.

The phenolic adhesion promoter may include a cured phenolic resin, an uncured phenolic resin, or a combination thereof. Examples of suitable adhesion promoters include phenolic resins, e.g.Phenol resins, and organosilanes, e.g. epoxy-, mercapto-or amine-functional silanes, e.g.An organosilane. By cured phenolic resin is meant a phenolic resin that has been co-reacted with monomers, oligomers and/or prepolymers.

The phenolic adhesion promoter may comprise the reaction product of a condensation reaction of a phenolic resin with one or more thiol-terminated polysulfides. The phenolic adhesion promoter may be thiol-terminated.

Examples of suitable phenol resins include those prepared from 2- (hydroxymethyl) phenol, (4-hydroxy-1, 3-phenylene) dimethanol, (2-hydroxybenz-1, 3, 4-triyl) tricarbol, 2-benzyl-6- (hydroxymethyl) phenol, (4-hydroxy-5- ((2-hydroxy-5- (hydroxymethyl) cyclohex-2, 4-dien-1-yl) methyl) -1, 3-phenylene) dimethanol, (4-hydroxy-5- ((2-hydroxy-3, 5-bis (hydroxymethyl) cyclohex-2, 4-dien-1-yl) methyl) -1, 3-phenylene) dimethanol and any combination of the foregoing. Suitable phenol resins can be synthesized by the base-catalyzed reaction of phenol with formaldehyde. Phenolic adhesion promoters may include those available from Durez CorporationResin, a,Resin orResins and polymers such asA reaction product of a condensation reaction of a thiol-terminated polysulfide such as a resin.Examples of the resin include75108 (allyl ethers of hydroxymethylphenol, see U.S. Pat. No. 3,517,082) and75202。examples of the resin include29101、29108、29112、29116、29008、29202、29401、29159、29181、92600、94635、94879 and94917。an example of a resin is34071。

The co-reactive composition may include an organofunctional alkoxysilane adhesion promoter, such as an organofunctional alkoxysilane. The organofunctional alkoxysilane may include a hydrolyzable group bonded to a silicon atom and at least one organofunctional group. The organofunctional alkoxysilane may have the structure R^a-(CH₂)_n-Si(-OR)_3-nR_nWherein R is^aIs an organofunctional group, n is 0, 1 or 2, and R is an alkyl group, such as methyl or ethyl. Examples of organic functional groups include epoxy, amino, methacryloxy, or sulfide groups. The organofunctional alkoxysilane may be a dialkoxy silane having two or more alkoxysilane groups, a functional dialkoxy silane, a non-functional dialkoxy silaneSilane, or a combination of any of the foregoing. The organofunctional alkoxysilane may be a combination of a monoalkoxysilane and a bifilar alkoxysilane.

Examples of suitable amino-functional alkoxysilanes under the trade name includeA-1100 (gamma-aminopropyltriethoxysilane),A-1108 (gamma-aminopropyl silsesquioxane),A-1110 (gamma-aminopropyltrimethoxysilane),1120 (N-beta- (aminoethyl) -gamma-aminopropyltrimethoxysilane),1128 (benzylamino-silane),A-1130 (triaminofunctional silane),Y-11699 (bis- (gamma-triethoxysilylpropyl) amine),A-1170 (bis- (gamma-trimethoxysilylpropyl) amine),A-1387 (Polyazaamides),Y-19139 (ethoxypolyazamide) anda-2120 (N-. beta. - (aminoethyl) - γ -aminopropylmethyldimethoxysilane). Suitable amine functional alkoxysilanes are commercially available from, for example, Gelest Inc, Dow Corning Corporation, and Momentive Performance Materials, Inc.

The co-reactive composition may include a filler or a combination of different fillers. The filler may include, for example, an inorganic filler, an organic filler, a low density filler, a conductive filler, or a combination of any of the foregoing.

The co-reactive composition used to form the multilayer sealing cap may include an inorganic filler or a combination of inorganic fillers.

Inorganic fillers may be included to provide mechanical reinforcement and to control the rheological properties of the composition, such as viscosity. Inorganic fillers may be added to the composition to impart desired physical properties, such as, for example, to improve impact strength, control viscosity, and/or modify the electrical properties of the cured composition.

Inorganic fillers that can be used in the co-reactive composition include carbon black, calcium carbonate, precipitated calcium carbonate, calcium hydroxide, hydrated alumina (aluminum hydroxide), talc, mica, titanium dioxide, aluminum silicate, carbonate, chalk, silicate, glass, metal oxide, graphite, and combinations of any of the foregoing.

Suitable calcium carbonate fillers may comprise those available from Solvay specialty Chemicals, for example31、312、U1S 1、UaS2、N2R、SPM andSPT, and the like. The calcium carbonate filler may comprise a combination of precipitated calcium carbonates.

The inorganic filler may be surface treated to provide a hydrophobic or hydrophilic surface, which may facilitate dispersion and compatibility of the inorganic filler with other components of the co-reactive composition. The inorganic filler may comprise surface-modified particles, such as surface-modified silica. The surface of the silica particles may be modified, for example to adjust the hydrophobicity or hydrophilicity of the surface of the silica particles. Surface modification can affect the dispensability, viscosity, cure rate, and/or adhesion of the particles.

The co-reactive composition may include an organic filler or a combination of organic fillers.

The organic filler may be selected to have low specific gravity and resistance to solvents such as JRF type I and/or to reduce the density of the sealant layer. Suitable organic fillers may also have acceptable adhesion to the sulfur-containing polymer matrix. The organic filler may comprise solid powders or particles, hollow powders or particles, or a combination thereof.

The organic filler may have a specific gravity of, for example, less than 1.15, less than 1.1, less than 1.05, less than 1, less than 0.95, less than 0.9, less than 0.8, or less than 0.7. The organic filler may have a specific gravity, for example, in the range of 0.85 to 1.15, in the range of 0.9 to 1.1, in the range of 0.9 to 1.05, or in the range of 0.85 to 1.05.

The organic filler may include, for example, a thermoplastic, a thermoset, or a combination thereof. Examples of suitable thermoplastics and thermosets include epoxy resins, epoxy amides, ETFE copolymers, nylons, polyethylenes, polypropylenes, polyethylene oxides, polypropylene oxides, polyvinylidene chlorides, polyvinyl fluorides, TFE, polyamides, polyimides, ethylene propylene, perfluorocarbons, vinyl fluorides, polycarbonates, polyether ether ketones, polyether ketones, polyphenylene oxides, polyphenylene sulfides, polystyrenes, polyvinyl chlorides, melamines, polyesters, phenolic resins, epichlorohydrin, fluorinated hydrocarbons, polycyclic compounds, polybutadienes, polychloroprenes, polyisoprenes, polysulfides, polyurethanes, isobutylene isoprene, silicones, styrene butadiene, liquid crystal polymers, or combinations of any of the foregoing.

Examples of suitable polyamide 6 and polyamide 12 particles are available from Toray Plastics as grades SP-500, SP-10, TR-1 and TR-2. Suitable polyamide powders are also available under the trade nameAvailable from Arkema Group and under the trade namePurchased from Evonik Industries.

The organic filler may have any suitable shape. For example, the organic filler may include a portion of the comminuted polymer that has been filtered to select a desired size range. The organic filler may comprise substantially spherical particles. The particles may be solid or porous.

The organic filler may have a number average particle diameter, for example, in the range of 1 μm to 100 μm, 2 μm to 40 μm, 2 μm to 30 μm, 4 μm to 25 μm, 4 μm to 20 μm, 2 μm to 12 μm, or 5 μm to 15 μm. The organic filler may have a number average particle size of, for example, less than 100 μm, less than 75 μm, less than 50 μm, less than 40 μm, or less than 20 μm. The particle size distribution can be determined using a fischer tropsch particle measurement instrument or by optical inspection.

The co-reactive composition used to form the sealing cap exhibiting low density can include, for example, a low density filler such as a low density organic filler, a hollow microsphere, a coated microsphere, or a combination of any of the foregoing.

The sealing cap may exhibit a specific gravity of, for example, less than 1.1, less than 1.0, less than 0.9, less than 0.8, or less than 0.7, wherein the specific gravity is determined according to ISO 2781 at 23 ℃/55% RH.

The organic filler may comprise low density, e.g. modified expanded thermoplastic microcapsules. Suitable modified expanded thermoplastic microcapsules may comprise an outer coating of melamine or urea/formaldehyde resin. The co-reactive composition may include low density microcapsules. The low density microcapsules may comprise thermally expandable microcapsules.

By thermally expandable microcapsules is meant hollow shells comprising a volatile material that expands at a predetermined temperature. The number average primary particle size of the thermally expandable thermoplastic microcapsules may be from 5 μm to 70 μm, in some cases from 10 μm to 24 μm or from 10 μm to 17 μm. The term "average primary particle size" refers to the average particle size (the numerically weighted average of the particle size distribution) of the microcapsules prior to any expansion. The particle size distribution can be determined using a fischer tropsch particle measurement instrument or by optical inspection.

Examples of materials suitable for forming the walls of the thermally expandable microcapsules include polymers of vinylidene chloride, acrylonitrile, styrene, polycarbonate, methyl methacrylate, ethyl acrylate, and vinyl acetate, copolymers of these monomers, and combinations of polymers and copolymers. The cross-linking agent may be contained in the material forming the wall of the thermally expandable microcapsules.

Examples of suitable thermoplastic microcapsules include Expancel available from akzo nobel^TMMicrocapsules, e.g. ofDE microspheres. Suitable Expancel^TMExamples of DE microspheres include920 DE 40 and920 DE 80. Suitable low density microcapsules are also available from Kureha Corporation.

The low density filler, such as a low density microcapsule, may be characterized by a specific gravity in the range of 0.01 to 0.09, 0.04 to 0.08, 0.01 to 0.07, 0.02 to 0.06, 0.03 to 0.05, 0.05 to 0.09, 0.06 to 0.09, or 0.07 to 0.09, wherein the specific gravity is determined according to ISO 787-11. The low density filler, such as a low density microcapsule, may be characterized by a specific gravity of less than 0.1, less than 0.09, less than 0.08, less than 0.07, less than 0.06, less than 0.05, less than 0.04, less than 0.03, or less than 0.02, wherein the specific gravity is determined in accordance with a ISO 787-11.

Low density fillers, such as low microcapsules, may be characterized by a number average particle size of, for example, 1 μm to 100 μm, and may have a substantially spherical shape. Low density fillers, such as low density microcapsules, can be characterized by an average particle size of, for example, 10 μm to 100 μm, 10 μm to 60 μm, 10 μm to 40 μm, or 10 μm to 30 μm, as determined according to ASTM D6913

The low density filler, such as low density microcapsules, may comprise expanded microcapsules or microspheres having a coating of an aminoplast resin, such as a melamine resin. Aminoplast resin coated particles are described, for example, in U.S. patent No. 8,993,691. Such microcapsules may be formed by heating microcapsules comprising a blowing agent surrounded by a thermoplastic shell. The uncoated, low density microcapsules may be reacted with an aminoplast resin such as a urea/formaldehyde resin to provide a coating of thermosetting resin on the outer surface of the particles.

With a coating of an aminoplast resin, the aminoplast-coated microcapsules may be characterized by a specific gravity, for example, in the range of 0.02 to 0.08, in the range of 0.02 to 0.07, in the range of 0.02 to 0.06, in the range of 0.03 to 0.07, in the range of 0.03 to 0.065, in the range of 0.04 to 0.065, in the range of 0.045 to 0.06, or in the range of 0.05 to 0.06, wherein the specific gravity is determined according to ISO 787-11.

The co-reactive composition may include a micronized oxidized polyethylene homopolymer. The organic filler may comprise polyethylene, for example polyethylene oxide powder. Suitable polyethylenes may be, for example, available under the trade nameAvailable from Honeywell International, Inc., under the trade nameFrom INEOS and under the trade nameCommercially available from Mitsui Chemicals America, inc.

The co-reactive composition can include, for example, 1 wt% to 90 wt% low density filler, 1 wt% to 60 wt%, 1 wt% to 40 wt%, 1 wt% to 20 wt%, 1 wt% to 10 wt%, or 1 wt% to 5 wt% low density filler, where wt% is by total weight of the composition.

The co-reactive composition can include greater than 1 wt% of the low density filler, greater than 1 wt%, greater than 2 wt%, greater than 3 wt%, greater than 4 wt%, greater than 1 wt%, or greater than 10 wt% of the low density filler, where wt% is based on the total weight of the composition.

The co-reactive composition can include from 1 vol% to 90 vol% low density filler, from 5 vol% to 70 vol%, from 10 vol% to 60 vol%, from 20 vol% to 50 vol%, or from 30 vol% to 40 vol% low density filler, where vol% is based on the total volume of the co-reactive composition.

The co-reactive composition can include greater than 0.5 vol% low density filler, greater than 1 vol%, greater than 5 vol%, greater than 10 vol%, greater than 20 vol%, greater than 30 vol%, greater than 40 vol%, greater than 50 vol%, greater than 60 vol%, greater than 70 vol%, or greater than 80 vol% low density filler, where vol% is based on the total volume of the co-reactive composition.

The co-reactive composition may comprise a conductive filler or a combination of conductive fillers. The conductive filler may comprise an electrically conductive filler, a semi-conductive filler, a thermally conductive filler, a magnetic filler, an EMI/RFI shielding filler, a static dissipative filler, an electrically active filler, or a combination of any of the foregoing.

Examples of suitable conductive fillers, such as conductive fillers, include metals, metal alloys, conductive oxides, semiconductors, carbon fibers, and combinations of any of the foregoing.

Other examples of the conductive filler include conductive noble metal-based fillers such as pure silver; noble metal-plated noble metals, such as silver-plated gold; noble metal plated non-noble metals, such as silver plated copper, nickel or aluminum, such as silver plated aluminum core particles or platinum plated copper particles; noble metal plated glass, plastic or ceramic, such as silver plated glass microspheres, noble metal plated aluminum or noble metal plated plastic microspheres; mica plated with noble metals; and other such noble metal conductive fillers. Non-noble metal based materials may also be used and include, for example, non-noble metal plated non-noble metals such as copper coated iron particles or nickel plated copper; non-noble metals, such as copper, aluminum, nickel, cobalt; non-noble metal plated non-metals, such as nickel plated graphite, and non-metallic materials, such as carbon black and graphite. Combinations of conductive fillers and shapes of conductive fillers may be used to achieve desired conductivity, EMI/RFI shielding efficiency, stiffness, and other properties suitable for a particular application.

The amount and type of conductive filler can be selected to produce a conductive filler that, when cured, exhibits less than 0.50 Ω/cm²Sheet resistance (four-point resistance) or less than 0.15. omega./cm²The sheet resistance of (a). The amount and type of filler can also be selected to provide effective EMI/RFI shielding for apertures sealed with the co-reactive composition in the frequency range of 1MHz to 18 GHz.

The organic, inorganic and low density fillers may be coated with a metal to provide a conductive filler.

The conductive filler may include graphene. Graphene comprises a dense honeycomb lattice of carbon atoms, the thickness of which is equal to the atomic size of one carbon atom, i.e. a single layer sp arranged in a two-dimensional lattice²Hybridized carbon atom.

The conductive filler may include a magnetic filler or a combination of magnetic fillers.

The magnetic filler may comprise a soft magnetic metal. This can enhance the magnetic permeability of the magnetic molding resin. As the main component of the soft magnetic metal, at least one magnetic material selected from the group consisting of Fe, Fe-Co, Fe-Ni, Fe-Al, and Fe-Si can be used. The magnetic filler may be a soft magnetic metal having a high bulk permeability. As the soft magnetic metal, at least one magnetic material of Fe, FeCo, FeNi, FeAl, and FeSi can be used. Specific examples include permalloy (FeNi alloy), superparamlloy (FeNiMo alloy), sendust (fesilal alloy), FeSi alloy, FeCo alloy, FeCr alloy, FeCrSi alloy, FeNiCo alloyAnd Fe. Other examples of the magnetic filler include iron-based powder, iron-nickel-based powder, iron powder, ferrite powder, Alnico powder, Sm₂Co₁₇Powder, Nd-B-Fe powder, barium ferrite BaFe₂O₄Bismuth ferrite BiFeO₃Chromium dioxide CrO₂SmFeN, NdFeB and SmCo.

The co-reactive composition may include a hydroxy-functional vinyl ether or a combination of hydroxy-functional vinyl ethers. Reactive diluents may be used to reduce the viscosity of the composition. The reactive diluent may be a low molecular weight compound, for example having a molecular weight of less than 400Da, having at least one functional group capable of reacting with at least one reactant of the composition and becoming part of the crosslinked network. The reactive diluent may have, for example, one functional group or two functional groups. The reactive diluent may be used to control the viscosity of the composition or to improve wetting of the filler in the co-reactive composition.

The hydroxy-functional vinyl ether as the reactive diluent may have the structure of formula (12):

CH₂＝CH-O-(CH₂)_t-OH (12)

where t is an integer from 2 to 10. In the hydroxy-functional vinyl ether of formula (12), t can be 1,2,3, 4, 5, or t can be 6. Examples of suitable hydroxy-functional vinyl ethers include 1-methyl-3-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, and combinations thereof. The hydroxy-functional vinyl ether may be 4-hydroxybutyl vinyl ether.

The co-reactive composition can include, for example, 0.1 wt% to 10 wt% of the hydroxy-functional vinyl ether, 0.2 wt% to 9 wt%, 0.3 wt% to 0.7 wt%, and 0.4 wt% to 0.7 wt%, where wt% is based on the total weight of the curable composition.

The co-reactive composition may include an amino-functional vinyl ether or a combination of amino-functional vinyl ethers as the reactive diluent.

The amino-functional vinyl ether as a reactive diluent may have the structure of formula (13):

CH₂＝CH-O-(CH₂)_w-NH₂ (13)

where w is an integer from 2 to 10. In the amino-functional vinyl ether of formula (13), w may be 1,2,3, 4, 5, or t may be 6. Examples of suitable amino-functional vinyl ethers include 1-methyl-3-aminopropyl vinyl ether, 4-aminobutyl vinyl ether, and combinations of any of the foregoing. The amino-functional vinyl ether may be 4-aminobutyl vinyl ether as a reactive diluent.

The coreactive composition may include, for example, 0.1 wt% to 10 wt% of the amino-functional vinyl ether, 0.2 wt% to 9 wt%, 0.3 wt% to 0.7 wt%, and 0.4 wt% to 0.7 wt%, where the wt% is based on the total weight of the coreactive composition.

The coreactive composition may include a vinyl-based diluent such as styrene, alpha-methylstyrene and p-vinyltoluene; vinyl acetate; and/or n-vinyl pyrrolidone as a reactive diluent.

The co-reactive composition may contain a plasticizer or a combination of plasticizers. Plasticizers may be included to adjust the viscosity of the composition and to facilitate application.

Examples of suitable plasticizers include phthalates, terephthalic acid, isophthalic acid, hydrogenated terphenyl, quaterphenyl and higher biphenyls or polybiphenyls, phthalates, chlorinated paraffins, modified polybiphenyls, tung oil, benzoates, dibenzoates, thermoplastic polyurethane plasticizers, phthalates, naphthalenesulfonates, trimellitates, adipates, sebacates, maleates, sulfonamides, organophosphates, polybutenes, butyl acetate, butyl cellosolve, butyl carbitol acetate, dipentene, tributyl phosphate, cetyl alcohol, diallyl phthalate, sucrose acetate isobutyrate, isooctyl resinate epoxy, benzophenones, and combinations of any of the foregoing.

The coreactive composition can include, for example, 0.5 wt% to 7 wt% of a plasticizer or combination of plasticizers, 1 wt% to 6 wt%, 2 wt% to 5 wt%, or 2 wt% to 4 wt% of a plasticizer or combination of plasticizers, where wt% is based on the total weight of the coreactive composition.

The coreactive composition can include, for example, less than 8 wt% plasticizer, less than 6 wt%, less than 4 wt%, or less than 2 wt% plasticizer or combination of plasticizers, where wt% is based on the total weight of the coreactive composition.

The co-reactive composition may include a photochromic agent that is sensitive to the degree of cure or exposure to actinic radiation. The cure indicator may change color upon exposure to actinic radiation, which may be permanent or reversible. The cure indicator may be initially transparent and become colored upon exposure to actinic radiation, or may be initially colored and become transparent upon exposure to actinic radiation.

The co-reactive compositions provided by the present disclosure may include a corrosion inhibitor or a combination of corrosion inhibitors.

Examples of suitable corrosion inhibitors include zinc phosphate based corrosion inhibitors, lithium silicate corrosion inhibitors, such as lithium orthosilicate (Li)₄SiO₄) And lithium metasilicate (Li)₂SiO₃) MgO, azoles, monomeric amino acids, dimeric amino acids, oligomeric amino acids, nitrogen-containing heterocyclic compounds, such as oxazoles, thiazoles, thiazolines, imidazoles, diazoles, pyridines, indolizines and triazines, tetrazoles and/or tolyltriazoles, corrosion-resistant particles, for example inorganic oxide particles, comprising, for example, zinc oxide (ZnO), magnesium oxide (MgO), cerium oxide (CeO)₂) Molybdenum oxide (MoO)₃) And/or silicon dioxide (SiO)₂) And combinations of any of the foregoing.

The co-reactive composition may include less than 5 wt% of a corrosion inhibitor or combination of corrosion inhibitors, less than 3 wt%, less than 2 wt%, less than 1 wt%, or less than 0.5 wt% of a corrosion inhibitor or combination of corrosion inhibitors, where the wt% is based on the total weight of the co-reactive composition.

The co-reactive composition may include a flame retardant or a combination of flame retardants.

The flame retardant may comprise an inorganic flame retardant, an organic flame retardant, or a combination thereof.

Examples of suitable inorganic flame retardants include aluminum hydroxide, magnesium hydroxide, zinc borate, antimony oxide, hydromagnesite, aluminum hydroxide (ATH), calcium phosphate, titanium oxide, zinc oxide, magnesium carbonate, barium sulfate, barium borate, kaolinite, silica, antimony oxide, and combinations of any of the foregoing.

Examples of suitable organic flame retardants include halocarbons, halogenated esters, halogenated ethers, chlorinated and/or brominated flame retardants, halogen-free compounds such as organic phosphorus compounds, organic nitrogen compounds, and the like, and combinations of any of the foregoing.

The coreactive composition can include, for example, from 1 wt% to 30 wt%, such as from 1 wt% to 20 wt% or from 1 wt% to 10 wt%, of a flame retardant or combination of flame retardants, based on the total weight of the coreactive composition. For example, the coreactive composition can include less than 30 wt%, less than 20 wt%, less than 10 wt%, less than 5 wt%, or less than 2 wt% of a flame retardant or combination of flame retardants, based on the total weight of the coreactive composition.

The co-reactive composition may include a moisture control additive or a combination of moisture control additives.

Examples of suitable moisture control additives include synthetic zeolites, activated alumina, silica gel, calcium oxide, magnesium oxide, molecular sieves, anhydrous sodium sulfate, anhydrous magnesium sulfate, alkoxysilanes, and combinations of any of the foregoing.

The coreactive composition can include less than 5 wt% of a moisture control additive or combination of moisture control additives, less than 3 wt%, less than 2 wt%, less than 1 wt%, or less than 0.5 wt% of a moisture control additive or combination of moisture control additives, where the wt% is based on the total weight of the coreactive composition.

The co-reactive composition may include a UV stabilizer or a combination of UV stabilizers. The UV stabilizer comprises a UV absorber and a hindered amine light stabilizer. Examples of suitable UV stabilizers include those available under the trade name(Solvay)、(BASF) and(BASF).

The layers of the sealing cap may be designed to optimize certain desired properties, including, for example, chemical resistance, corrosion resistance, hydrolytic stability, low temperature flexibility, high temperature resistance, and/or the ability to dissipate electrical charge. The material of the layers forming the sealing cap, such as the sealing cap shell, the material filling the interior, and/or the material of the other layers may be selected to optimize one or more desired properties.

For example, a layer exhibiting low temperature flexibility may include a prepolymer, such as silicone, polytetrafluoroethylene, polythioethers, polysulfides, polyformals, polybutadiene, certain elastomers, and combinations of any of the foregoing.

The layer exhibiting hydrolytic stability can include, for example, a prepolymer such as silicone, polytetrafluoroethylene, polythioethers, polysulfides, polyformals, polybutadiene, certain elastomers, and combinations of any of the foregoing, or a composition having a high crosslink density and/or can include an elastomer.

The layer exhibiting high temperature resistance can include, for example, a prepolymer, such as silicone, polytetrafluoroethylene, polythioethers, polysulfides, polyformals, polybutadiene, certain elastomers, and combinations of any of the foregoing; or a composition having a high crosslink density.

The layer exhibiting high tensile strength may include, for example, an elastic prepolymer, such as silicone and polybutadiene, a composition having a high crosslink density, an inorganic filler, and a combination of any of the foregoing.

The layer exhibiting high% elongation may include, for example, an elastic prepolymer, such as silicone and polybutadiene, a composition having a high crosslink density, an inorganic filler, and a combination of any of the foregoing.

The layer exhibiting substrate adhesion or adhesion to the primer coating may include, for example, an adhesion promoter such as an organofunctional alkoxysilane, a phenolic resin, a cured phenolic resin, and combinations of any of the foregoing, a titanate, a partially hydrolyzed alkoxysilane, or combinations thereof.

The layer exhibiting interlayer adhesion can include, for example, adhesion promoters, unreacted functional groups reactive with compounds in adjacent layers, and combinations thereof.

The layer exhibiting a fast tack free time may include, for example, a co-reactant having a fast cure chemistry, a system curable by actinic radiation, a catalyst, and combinations of any of the foregoing.

The layer exhibiting a fast shore 10A hardness time may include, for example, a co-reactant having a fast cure chemistry, a system curable by actinic radiation, a catalyst, and a combination of any of the foregoing.

The layer exhibiting electrical conductivity, EMI/RFI shielding and/or static dissipation may comprise, for example, a conductive filler or a combination of conductive fillers.

The layer exhibiting low density may comprise, for example, low density fillers such as low density organic fillers, hollow microspheres, coated microspheres, or a combination of any of the foregoing.

The layer exhibiting corrosion resistance may include, for example, one or more corrosion inhibitors.

The layer exhibiting corrosion resistance may comprise, for example, one or more inorganic fillers.

The method of the present invention uses co-reactive three-dimensional printing to fabricate a sealing cap or portion of a sealing cap. Co-reactive three-dimensional printing refers to an automated manufacturing process in which a co-reactive composition is extruded through a nozzle and deposited using automated control. In co-reactive three-dimensional printing, a single portion of a co-reactive composition can be pumped into a three-dimensional printing apparatus and a curing reaction can be initiated by application of energy, for example, by exposing the co-reactive composition to UV radiation. Alternatively, at least two coreactive components can be combined and mixed to form a coreactive composition, which can then be extruded through a nozzle and deposited.

A three-dimensional printing apparatus for manufacturing a part may include one or more pumps, one or more mixers, and one or more nozzles. One or more coreactive compositions may be pumped into one or more mixers and forced under pressure through one or more nozzles and directed onto a surface or onto a previously applied layer.

The three-dimensional printing apparatus can include, for example, pressure control, extrusion dies, coextrusion dies, coating applicators, temperature control elements, elements for applying energy to the co-reactive composition, or a combination of any of the foregoing.

The three-dimensional printing apparatus may comprise a build apparatus for moving the nozzle in three dimensions relative to the surface. The movement of the three-dimensional printing device may be controlled by a processor.

Any suitable co-reactive three-dimensional printing apparatus can be used to deposit the co-reactive composition. The selection of a suitable coreactive three-dimensional printing apparatus may depend on a number of factors, including the deposition volume, the viscosity of the coreactive composition, the deposition rate, the reaction rate of the coreactive compound, and the complexity and size of the chemically-resistant portion being fabricated. Each of the two or more coreactive components can be introduced into separate pumps and injected into a mixer to combine and mix the two coreactive components to form a coreactive composition. A nozzle can be coupled to the mixer, and the mixed co-reactive composition can be forced under pressure or extruded through the nozzle.

The pump may be, for example, a positive displacement pump, a syringe pump, a piston pump, or a progressive cavity pump. The two pumps delivering the two co-reactive components may be placed in parallel or in series. A suitable pump may be capable of pushing a liquid or viscous liquid through the nozzle orifice. This process may also be referred to as extrusion. The co-reactive components can also be introduced into the mixer using two pumps in series.

For example, two or more co-reactive components may be deposited by dispensing the material through a disposable nozzle attached to a progressive cavity two-component system in which the co-reactive components are mixed in-line. The two-component system may include, for example, two progressive cavity pumps that respectively deliver the co-reactive components to a disposable static mixer dispenser or a dynamic mixer. Other suitable pumps include positive displacement pumps, syringe pumps, piston pumps, and progressive cavity pumps. After mixing to form the coreactive composition, the coreactive composition is forced under pressure through one or more dies and/or one or more nozzles to form an extrudate for deposition onto the base to provide an initial layer of chemically resistant moieties, and successive layers can be deposited on and/or adjacent to previously deposited layers. The deposition system may be placed orthogonal to the base, but may also be disposed at any suitable angle to form an extrudate such that the extrudate and the deposition system form an obtuse angle, wherein the extrudate is parallel to the base. By extrudate is meant the coreactive composition after the coreactive components are mixed, for example, in a static mixer or a dynamic mixer. The extrudate may be shaped while passing through a die and/or nozzle.

The base, the deposition system, or both the base and the deposition system may be hinged to build a three-dimensional chemical-resistant portion. The movement may be performed in a predetermined manner, which may be done using any suitable CAD/CAM method and equipment such as a robotic and/or computerized machine interface.

The extrudate formed by extruding the co-reactive composition through the nozzle of the three-dimensional printing apparatus can be deposited in any orientation. For example, the nozzles may be oriented downward, upward, sideways, or at any angle therebetween. In this manner, the co-reactive composition may be deposited as vertical walls or as an overhang. The extrudate may be deposited on the bottom of a vertical wall, the lower surface of an inclined wall, or a horizontal surface. Using an extrudate with a fast curing chemistry may facilitate the ability of the upper layer to be deposited adjacent to the lower layer so that an angled surface may be produced. The angled surface may be inclined upwardly relative to the horizontal or downwardly relative to the horizontal.

The extrudate may be continuously or intermittently dispensed to form an initial layer and a continuous layer. For intermittent deposition, the deposition system can interface with a switch to turn off a pump, such as a progressive cavity pump, and thereby interrupt the flow of the co-reactive composition.

The three-dimensional printing system can include an in-line static and/or dynamic mixer and a separate pressurized pumping compartment to contain and feed at least two co-reactive components into the static and/or dynamic mixer. Mixers such as active mixers may include a variable speed central impeller with high shear blades within the nozzle. A series of nozzles with a minimum dimension of, for example, 0.2mm to 100mm, 0.5mm to 75mm, 1mm to 50mm, or 5mm to 25mm may be used. The nozzle may have a minimum dimension of, for example, greater than 1mm, greater than 2mm, greater than 5mm, greater than 10mm, greater than 20mm, greater than 30mm, greater than 40mm, greater than 50mm, greater than 60mm, greater than 70mm, greater than 80mm, or greater than 90 mm. The nozzle may have a minimum dimension of, for example, less than 100mm, less than 90mm, less than 80mm, less than 70mm, less than 60mm, less than 50mm, less than 40mm, less than 30mm, less than 20mm, less than 10mm, or less than 5 mm. The nozzle may have any suitable cross-sectional dimension such as, for example, circular, spherical, elliptical, rectangular, square, trapezoidal, triangular, planar, or other suitable shape. The ratio of the aspect ratio or orthogonal dimensions may be any suitable dimension suitable for making a chemical resistant moiety, such as 1:1, greater than 1:2, greater than 1:3, greater than 1:5, or greater than 1: 10.

A series of static and/or dynamic mixing nozzles may be used having, for example, an exit orifice size of 0.6mm to 2.5mm and a length of 30mm to 150 mm. For example, the exit orifice diameter may be 0.2mm to 4.0mm, 0.4mm to 3.0mm, 0.6mm to 2.5mm, 0.8mm to 2mm, or 1.0mm to 1.6 mm. The static mixer and/or the dynamic mixer may have a length of, for example, 10mm to 200mm, 20mm to 175mm, 30mm to 150mm, or 50mm to 100 mm. The mixing nozzle may include a static and/or dynamic mixing section and a distribution section coupled to the static and/or dynamic mixing section. The static and/or dynamic mixing section may be configured to combine and mix the co-reactive materials. The distribution section may be, for example, a straight pipe having any of the above-described hole diameters. The length of the dispensing section may be configured to provide a region in which the co-reactive components may begin to react and increase viscosity prior to deposition on the article. For example, the length of the dispensing section may be selected based on the deposition rate, the reaction rate of the co-reactant, and the viscosity of the co-reactive composition.

The co-reactive composition can have a residence time in the static and/or dynamic mixing nozzle of, for example, 0.25 seconds to 5 seconds, 0.3 seconds to 4 seconds, 0.5 seconds to 3 seconds, or 1 second to 3 seconds. Other residence times may be suitably employed based on the cure chemistry and cure rate.

Generally, suitable residence times are less than the gel time of the coreactive composition.

The co-reactive composition can have a volumetric flow rate of, for example, 0.1 mL/min to 20,000 mL/min, such as 1 mL/min to 12,000 mL/min, 5 mL/min to 8,000 mL/min, or 10 mL/min to 6,000 mL/min. The volumetric flow rate may depend on, for example, the viscosity of the coreactive composition, the extrusion pressure, the nozzle diameter, and the reaction rate of the coreactive compound.

The co-reactive composition may be applied at a deposition rate of, for example, 1 mm/sec to 400 mm/sec, such as5 mm/sec to 300 mm/sec, 10 mm/sec to 200 mm/sec, or 15 mm/sec to 150 mm/sec. The deposition rate may depend on, for example, the viscosity of the coreactive composition, the extrusion pressure, the nozzle diameter, and the reaction rate of the coreactive compound. Deposition rate refers to the speed at which the nozzle used to extrude the coreactive composition moves relative to the surface on which the coreactive composition is deposited.

Static and/or dynamic mixing nozzles may be heated or cooled to control, for example, the rate of reaction between the co-reactive compounds and/or the viscosity of the co-reactive components. The apertures of the deposition nozzles may have any suitable shape and size. The system may include a plurality of deposition nozzles. The nozzle may have a fixed orifice size and shape, or the nozzle orifice may be controllably adjustable. The mixer and/or nozzle may be cooled to control the exotherm generated by the reaction of the co-reactive compound.

The rate at which the coreactive composition reacts to form the thermoset polymeric matrix may be determined and/or controlled by the selection of the reactive functional groups of the coreactive compound. The reaction rate may also be determined by factors that reduce the activation energy of the reaction, such as heat and/or catalyst.

The reaction rate can be reflected in the gel time of the coreactive composition. Fast cure chemistry refers to chemistry in which the gel time of the co-reactive compound is, for example, less than 30 minutes, less than 20 minutes, less than 10 minutes, less than 5 minutes, less than 4 minutes, less than 3 minutes, less than 2 minutes, less than 1 minute, less than 45 seconds, less than 30 seconds, less than 15 seconds, or less than 5 seconds. The co-reactive composition may have a gel time of, for example, 0.1 second to 5 minutes, 0.2 second to 3 minutes, 0.5 second to 2 minutes, 1 second to 1 minute, or 2 seconds to 40 seconds. The gel time is the time after mixing of the coreactive components when the coreactive composition can no longer be stirred by hand. The gel time of the latent coreactive composition refers to the time from the first initiation of the curing reaction to the point where no further hand agitation of the coreactive composition is possible.

The size of the co-reactive composition and the extrudate forced through the nozzle is not particularly limited as the co-reactive components can be uniformly combined and mixed and the co-reactive composition can begin to solidify immediately after mixing. Thus, co-reactive additive manufacturing facilitates the use of large size extrudates, which facilitates the ability to quickly manufacture small and large sealing caps.

Using a co-reactive three-dimensional printing process, a co-reactive composition can be deposited, for example, at a speed of 1 mm/sec to 400 mm/sec and/or a flow rate of 0.1 mL/min to 20,000 mL/min.

The sealing cap and the layer of the sealing cap comprising the sealing cap shell may have a visually smooth surface. Photographs of the capsule are shown in fig. 3A-3B, which illustrate a capsule with a gradually smooth surface (from fig. 3A to 3C) achieved by reducing the thickness of the print layer. Fig. 3D shows a confocal laser scanning micro surface profile at 10X magnification of the outer surface of the corresponding seal cap shell shown in fig. 3A-3C. The seal cap and seal cap surface shown in fig. 3A-3D are made using a polyurea co-reactive composition formed by combining a polyamine component and a polyisocyanate component.

The sealing cap may have properties suitable for a particular use. Relevant properties include chemical resistance, low temperature flexibility, hydrolytic stability, high temperature resistance, tensile strength, elongation%, substrate adhesion, adhesion to an adjacent sealant layer, tack free time, shore 10A hardness time, electrical conductivity, static dissipation, thermal conductivity, low density, corrosion resistance, surface hardness, flame retardancy, UV resistance, rain erosion resistance, dielectric breakdown strength, and combinations of any of the foregoing.

For aerospace applications, properties may include chemical resistance, such as resistance to fuels, hydraulic fluids, oils, greases, lubricants, and solvents, low temperature flexibility, high temperature resistance, ability to dissipate charge, and/or dielectric breakdown strength. When fully cured, the sealing cap may be visually transparent to facilitate visual inspection of the interface between the fastener and the sealant.

When fully cured, the shell and the internal volume comprising the cured second coreactive composition may exhibit one or more different properties. For example, the shell can exhibit chemical resistance, electrical conductivity, hydrolytic stability, high dielectric breakdown strength, or a combination of any of the foregoing. For example, when cured, the second co-reactive composition may exhibit adhesion to a fastener, chemical resistance, low density, high tensile strength, high% elongation, or a combination of any of the foregoing.

The volume expansion percentage of the sealing cap after immersion in JRF type I at 140 ° f (60 ℃) and ambient pressure is no greater than 40%, in some cases no greater than 25%, in some cases no greater than 20%, and in other cases no greater than 10%, according to a method similar to that described in ASTM D792 (american society for testing and materials) or AMS 3269 (aerospace material specifications). JRF type I, for determining fuel resistance, having the following composition: toluene: 28 plus or minus 1% volume; cyclohexane (industrial): 34 + -1% by volume; isooctane: 38 + -1% by volume; and tert-dibutyl disulfide: 1 + -0.005% by volume (see AMS 2629, published 7/1/1989, § 3.1.1 etc., available from SAE (society of automotive Engineers)).

After exposure to a jet reference fluid (JRF type 1) at 60 ℃ for 168 hours according to ISO 1817, the provided cured composition may exhibit a tensile strength of greater than 1.4MPa determined according to ISO 37, a tensile elongation of greater than 150% determined according to ISO 37, and a hardness of greater than shore 30A determined according to ISO 868, wherein the tests are conducted at a temperature of 23 ℃ and humidity of 55% RH.

After 168 hours of exposure to a deicing fluid at 60 ℃ according to ISO 110751 type, the cured composition may exhibit a tensile strength of greater than 1MPa determined according to ISO 37 and a tensile elongation of greater than 150% determined according to ISO 37, with the tests being carried out at a temperature of 23 ℃ and a humidity of 55% RH.

Exposure to phosphate ester hydraulic fluid at 70: (LD-4) after 1,000 hoursThe cured composition may exhibit a tensile strength of greater than 1MPa as determined according to ISO 37, a tensile elongation of greater than 150% as determined according to ISO 37 and a hardness of greater than shore 30A as determined according to ISO 868, wherein the testing is conducted at a temperature of 23 ℃ and a humidity of 55% RH. The chemical resistant composition may exhibit less than 25%, less than 20%, less than 15%, or less than 10% swelling after 7 days immersion in a chemical at 70 ℃, wherein the% swelling is determined according to EN ISO 10563.

The sealing cap may exhibit a hardness of, for example, greater than shore 20A, greater than shore 30A, greater than shore 40A, greater than shore 50A, or greater than shore 60A, wherein the hardness is determined according to ISO 868 at 23 ℃/55% RH.

The seal cap may exhibit a tensile elongation of at least 200% and a tensile strength of at least 200psi when measured according to the procedures described in AMS 3279, § 3.3.17.1, test procedures AS5127/1, § 7.7.

The lap shear strength of the seal cap can be greater than 200psi (1.38MPa), such AS at least 220psi (1.52MPa), at least 250psi (1.72MPa), and in some cases at least 400psi (2.76MPa), when measured according to the procedure described in SAE AS5127/1, paragraph 7.8.

The sealing caps prepared from the co-reactive compositions provided by the present disclosure may meet or exceed the requirements of aerospace sealants set forth in AMS 3277.

The conductive sealing cap or layer of the sealing cap provided by the present disclosure may exhibit, for example, less than 10⁶Ohm/square, less than 10⁵Ohm/square, less than 10⁴Ohm/square, less than 10³Ohm/square, less than 10²Ohm/square, less than 10^-1Ohm/square or less than 10^-2Surface resistivity in ohms/square. The surface of the conductive sealing cap or layer of the sealing cap provided by the present disclosure may have, for example, 10^-2To 10²、10²Ohm/square to 10⁶Ohm/square or 10³Ohm/square to 10⁵Surface resistivity in ohms/square. Surface resistivity can be determined according to ASTM D257 at 23 ℃/55% RH.

The seal cap or layer of the seal cap provided by the present disclosure may have, for example, less than 10⁶Ohm/cm, less than 10⁵Ohm/cm, less than 10⁴Ohm/cm, less than 10³Ohm/cm, less than 10²Ohm/cm, less than 10^-1Ohm/cm or less than 10^-2Volume resistivity in ohms/cm. The electrically conductive sealing cap or the layer of the sealing cap may have, for example, 10^-2Ohm/cm to 10¹Ohm/cm, 10²Ohm/cm to 10⁶Ohm/cm or 10³Ohm/cm to 10⁵Volume resistivity in ohms/cm. Volume resistivity can be determined according to ASTM D257 at 23 ℃/55% RH.

The sealing cap or layer of the sealing cap provided by the present disclosure may have, for example, greater than 1S cm^-1Greater than 10S cm^-1Greater than 100S cm^-1Greater than 1,000S cm^-1Or greater than 10,000S cm^-1The electrical conductivity of (1). The conductive sealing cap may have a 1S cm^-1To 10,000S cm^-1、10S cm^-1To 1,000S cm^-1Or 10S cm^-1To 500S cm^-1The electrical conductivity of (1).

The sealing cap or layers of the sealing cap provided by the present disclosure may exhibit an attenuation of, for example, greater than 10dB, greater than 30dB, greater than 60dB, greater than 90dB, or greater than 120dB at a frequency in the range of 10KHz to 20 GHz. The conductive sealing cap provided by the present disclosure may exhibit an attenuation of, for example, 10dB to 120dB, 20dB to 100dB, 30dB to 90dB, or 40dB to 70dB at a frequency in the range of 10KHz to 20 GHz.

The sealing caps or layers of sealing caps provided by the present disclosure exhibit a thermal conductivity of 0.1 to 50W/(m-K), 0.5 to 30W/(m-K), 1 to 20W/(m-K), 1 to 10W/(m-K), 1 to 5W/(m-K), 2 to 25W/(m-K), or 5 to 25W/(m-K).

The sealing cap or layer of the sealing cap provided by the present disclosure can exhibit a specific gravity of, for example, less than 1.1, less than 1.0, less than 0.9, less than 0.8, or less than 0.7, wherein the specific gravity is determined according to ISO 2781 at 23 ℃/55% RH.

The co-reactive three-dimensional printing method provided by the present disclosure can be used to manufacture sealing caps with adjacent layers having high mechanical strength. Adjacent layers of the co-reactive composition may be chemically bonded and/or physically bonded to create an interlayer interface of high mechanical strength. The strength of the interlayer interface can be determined by measuring the fracture energy according to ASTM D7313. The sealing cap made using the methods provided by the present disclosure may have a fracture energy that is substantially the same as the fracture energy of the individual layers. For example, the energy to break of the sealing cap and the energy to break of the single cured layer of the co-reactive composition can be within, for example, less than 10%, less than 5%, less than 2%, or less than 1%.

The sealing cap provided by the present disclosure may be used to seal a fastener. Examples of fasteners include anchors, cap screws, cotter pins, eyebolts, nuts, rivets, self-locking fasteners, self-tapping screws, sleeves, thread screws, tum and thumb screws, welding screws, bending bolts, fixed panel fasteners, machine screws, retaining rings, screw driver insert bits, self-drilling screws, self-expanding metal brackets, spring nuts, thread rolling screws, and washers.

The fastener may be a fastener on a surface of a vehicle, including, for example, an automobile, an aerospace vehicle, an automobile, a truck, a bus, a van, a motorcycle, a scooter, a recreational vehicle; trains, trams, bicycles, airplanes, rockets, spacecraft, jet planes, helicopters, military vehicles, including jeep, transport, combat support, troop, infantry combat, mine protection, light armored, light utility, military trucks, watercraft, including ships, boats, and recreational boats. The term "vehicle" is used in its broadest sense and encompasses all types of aircraft, spacecraft, watercraft and land vehicles. For example, the vehicle may comprise an aircraft, such as an airplane, including a private aircraft; and small, medium or large commercial passenger, cargo and military aircraft; helicopters, including private, commercial, and military helicopters; aerospace vehicles, including rockets and other spacecraft. The vehicle may comprise a land vehicle such as, for example, a trailer, car, truck, bus, van, engineering vehicle, golf cart, motorcycle, bicycle, train, and railroad car. Vehicles also include watercraft such as, for example, boats, and hovercraft.

The fastener may be a fastener on a surface of an aerospace vehicle. Examples of aerospace vehicles include F/A-18 jet aircraft or related aircraft, such as F/A-18E super bumblebee and F/A-18F; boeing 787 fantasy airliners (787 dreaminer), 737, 747, 717 jet airliners, related aircraft (manufactured by Boeing Commercial aircrafts); v-22 Osprey type inclined rotor wing aircraft (V-22 Osprey); VH-92, S-92 and related aircraft (produced by the U.S. naval aviation systems department of command (NAVAIR) and Sekorsky aircraft corporation (Sikorsky)); g650, G600, G550, G500, G450 and related aircraft (produced by Gulfstream); and a350, a320, a330 and related aircraft (manufactured by Airbus corporation (Airbus)). The sealing cap may be used in any suitable commercial, military, or general aviation aircraft, such as, for example, aircraft produced by pombodi corporation (bombodier Inc.) and/or pombodi Aerospace corporation (bombodier Aerospace), such as canadian Regional aircraft (CRJ) and related aircraft; aircraft produced by Rockheed Martin, Inc. (Lockheed Martin), such as F-22 bird warrior (F-22 Raptor), F-35 Lightning fighter (F-35 Lightning) and related aircraft; aircraft produced by Northrop Grumman, such as B-2 ghost strategic bombers (B-2 Spirit) and related aircraft; aircraft manufactured by piranus aircrafts Ltd (Pilatus Aircraft Ltd.); aircraft manufactured by Eclipse Aviation Corporation; or Aircraft manufactured by Eclipse Aerospace, Kestrel Aircraft, Inc. (Kestrel Aircraft).

The fastener may be a fastener on a fuel container, such as a fuel tank of an aerospace vehicle.

The fastener may be a fastener that is protected from exposure to solvents such as fuel and/or hydraulic fluid under conditions of use.

Vehicles such as automotive and aerospace vehicles that include fasteners sealed using the methods provided by the present disclosure are also encompassed within the scope of the invention.

Aspects of the invention

The invention can be further defined by one or more of the following aspects.

Aspect 1. a method of sealing a fastener comprising depositing a continuous layer comprising a first co-reactive composition directly onto the fastener by three-dimensional printing.

Aspect 2 the method of aspect 1, wherein the continuous layer is deposited to form a sealing cap.

Aspect 3. the method of any one of aspects 1 and 2, further comprising: depositing a second coreactive composition directly onto said first coreactive composition; or depositing successive layers of the first and second coreactive compositions onto the fastener simultaneously.

Aspect 4. the method of any of aspects 1-3, further comprising applying a hermetic cap shell to the outermost deposited first coreactive composition, wherein the hermetic cap shell comprises an at least partially cured second coreactive composition; and said second coreactive composition is the same as or different from said outermost deposited coreactive composition.

Aspect 5. the method of any of aspects 1 and 2, further comprising depositing a continuous layer of a second coreactive composition by three-dimensional printing to form the seal cap shell over the first coreactive composition.

Aspect 6a method of manufacturing a sealing cap, comprising: depositing successive layers of a first co-reactive composition by three-dimensional printing to form a sealed cap shell defining an interior volume; and filling the interior volume with a second co-reactive composition to provide a sealing cap.

Aspect 7. the method of aspect 6, wherein filling the internal volume comprises depositing the second co-reactive composition using three-dimensional printing.

Aspect 8. the method of any of aspects 4 to 7, wherein the sealing cap shell is in the shape of a dome having a base width of 5mm to 50mm, preferably 10mm to 40 mm; a height of 5mm to 50mm, preferably 20mm to 40 mm; and an average wall thickness of 0.5mm to 25mm, preferably 1mm to 20mm, 1.5mm to 15mm or 2mm to 10 mm.

Aspect 9. the method of any of aspects 3-8, where the first coreactive composition is reactive with the second coreactive composition.

Aspect 10. the method of any of aspects 3-9, wherein the second coreactive composition is the same as the first coreactive composition.

Aspect 11. the method of any of aspects 3-9, wherein the second coreactive composition is different from the first coreactive composition.

Aspect 12 the method of any of aspects 6-11, further comprising at least partially curing the seal cap shell after forming the shell and before filling the interior volume.

Aspect 13. the method of any of aspects 3-12, wherein each of the first and second coreactive compositions independently comprises a sulfur-containing prepolymer.

Aspect 14. the method of aspect 13, wherein each of the first and second coreactive compositions independently comprises from 40 wt% to 80 wt% of the sulfur-containing prepolymer.

Aspect 15. the method of any one of aspects 13 to 14, wherein the sulfur content of the sulfur-containing prepolymer is greater than 10 wt%, wherein wt% is based on the total weight of the sulfur-containing prepolymer.

The method of aspect 16. the method of any of aspects 13-14, wherein the sulfur-containing prepolymer comprises a polythioether, a polysulfide, a sulfur-containing polyformal, a monosulfide, or a combination of any of the foregoing.

Aspect 17. the method of any of aspects 3-16, wherein each of the first and second coreactive compositions independently comprises an actinic radiation curable coreactive composition; and the method further comprises exposing the first and/or second coreactive compositions to actinic radiation prior to depositing the first and/or second coreactive compositions, while depositing the first and/or second coreactive compositions and/or after depositing the first and/or second coreactive compositions.

Aspect 18. the method of any of aspects 1-16, wherein the first co-reactive composition is curable upon exposure to actinic radiation.

Aspect 19. the method of any of aspects 3-16, wherein the first co-reactive composition is not curable upon exposure to actinic radiation.

Aspect 20a sealing cap manufactured using the method of any one of aspects 1 to 19.

Aspect 21 the sealing cap of aspect 20, wherein the fracture energy of the fully cured sealing cap is substantially the same as the fracture energy of the individual layers forming the sealing cap, wherein the fracture energy is determined according to ASTM D7313.

Aspect 22. a sealing cap made using the method of any of aspects 3-19, wherein a layer made from the first coreactive composition is chemically and/or physically bonded to a layer made from the second coreactive composition.

Aspect 23. a method of sealing a fastener comprising applying a sealing cap according to any of aspects 20 to 22 over a fastener and allowing the first and/or second coreactive compositions to cure.

Aspect 24. a fastener sealed with the sealing cap of any of aspects 20 to 22

Aspect 25 the fastener of aspect 24, wherein the fastener is on a vehicle, such as an aerospace vehicle.

Examples of the invention

Embodiments provided by the present disclosure are further illustrated by reference to the following examples describing methods of sealing fasteners and methods of manufacturing sealing caps using three-dimensional printing. It will be apparent to those skilled in the art that many modifications, both to materials and methods, may be practiced without departing from the scope of the present disclosure.

Example 1

UV curing sealing cap

A one-part fuel resistant sealant formulation available from PPG Aerospace, PR 2001B 2 Aerospace sealant, comprises a combination of thiol-terminated polythioether prepolymer, divinyl ether monomer, rheology modifier, filler, and photoinitiator. The formulations were stored at-40 ℃ in UV opaque tubes and thawed to room temperature (25 ℃) prior to use. The sealant formulation was introduced into a three-dimensional printing system consisting of a LulzBot Taz 3D printing gantry and a printing bed integrated with a ViscoTec Eco-Duo dual extruder. A UV source (A)WF-501B UV LED flashlight, 395nm peak wavelength) was mounted on the ViscoTec extruder and oriented from the extruder to the point of application at 5.5cm from the print bed.

The fuel-resistant sealant formulation was loaded into an opaque Nordson cartridge that was connected to a ViscoTec extruder using ambient light shielded PTFE tubing. The loaded cartridge was pressurized to 80psi under nitrogen and printed using custom written G-code, which simultaneously directed the print head and print bed and simultaneously switched the flow of formulation through the ViscoTec unit. The fuel-resistant sealant formulation was extruded through a static mixing nozzle with an inner diameter of 0.6mm onto the print bed. The sealing cap was constructed by depositing a continuous spiral of sealant using a print head speed of 120 mm/sec and a flow rate of 1.2 mL/min. Under these conditions, the extruded sealant formulation had a G "of about 8E4 and a G 'of 1E 53 hours after activation and a G" of 3E5 and a G' of 8.5E 56 hours after activation. The shear storage modulus G 'and the shear loss modulus G' were measured using an Anton Paar MCR 302 rheometer with a gap set at 1mm, a parallel plate axis diameter of 2mm, an oscillation frequency of 1Hz, an amplitude of 0.3%, and a plate temperature of 25 ℃. The sealing cap was modeled as a dome-like structure using 3D modeling software. The diameter of the bottom of the sealing cap is 42.4mm, and the height is 39.9 mm.

Example 2

Sealing caps made using thiol/epoxy chemistry

A co-reactive composition was prepared by combining a first component based on PR-2001B 1/2 (a two part thiol/epoxy Aerospace sealant available from PPG Aerospace) and a second component.

First component PR-2001B 1/2 part B contains a thiol-terminated polythioether prepolymer, an epoxy-functional alkoxysilane adhesion promoter, and partially hydrogenated tetrabiphenyl and higher order polybiphenyls. Weigh the first component into a Max 300L DAC cup (FlackTek) and use the standardThe procedure was followed for degassing.

Second component PR-2001B 1/2 part A comprises bisphenol-A- (epichlorohydrin); and (3) epoxy resin. The second component was weighed into a Max 300L DAC cup (FlackTek) and standard was usedThe procedure was followed for degassing.

Using FlackTekTransferring degassed components from DAC cupsIn a box, and a co-reactive composition was formed by mixing the two components in a weight ratio of 100: 18.5. The co-reactive compositions were printed using a ViscoTec 2K extruder mounted to a Lulzbot Taz 6 gantry.

Successive layers of a co-reactive composition are deposited to build up a hermetic cap shell.

Example 3

₂Sealing caps made using MnO catalyzed polysulfide chemistry

Coreactive compositions were prepared by combining a first coreactive component based on PR-1429B 2 (a two part Mn dioxide cured polysulfide Aerospace sealant available from PPG Aerospace) with a second coreactive component.

First coreactive component PR-1429B 2 part B comprises a thiol-terminated polysulfide prepolymer. The first coreactive component was weighed into a Max 300L DAC cup (FlackTek) and standard was usedThe procedure was followed for degassing.

Second coreactive component PR-1429B 2 part A contains MnO₂A catalyst. The second component was weighed into a Max 300L DAC cup (FlackTek) and standard was usedThe procedure was followed for degassing.

Using FlackTekThe degassed co-reactive components were transferred from the DAC cups into an Optimum box and the co-reactive composition formed by mixing the two components in a weight ratio of 100:10 was printed using a ViscoTec 2K extruder mounted to a Lulzbot Taz 6 dragon.

Successive layers of a co-reactive composition are deposited to build up a hermetic cap shell.

Example 4

UV-cured polythioether sealing caps

Aerospace seal caps are 3D printed using actinic radiation curable thiol-based resin formulations.

The thiol-ene formulation comprises a mixture of thiol-terminated and alkenyl-terminated resins, a rheology modifier, a filler, and a photoinitiator. The formulations were stored at-40 ℃ in UVIn a clear tube and thawed to 23 ℃ before use. Thiol-ene formulations were 3D printed using a custom made 3D printer with a LulzBot Taz 3D print gantry and ViscoTecEco-DUO Dual extruder Integrated print bed composition. A UV source (A)WF-501B UV LED flashlight, nominal peak wavelength 395nm) was mounted on a ViscoTec extruder and oriented from the extruder to the point of application at 5.5cm from the print bed.

The thiol and ene based compositions were loaded into an opaque Nordson cassette that was connected to a ViscoTec extruder using teflon tubing wrapped with aluminum foil to prevent ambient light penetration. The loaded cassette was pressurized to 80psi (0.551N/mm) under nitrogen²) And printed using custom written G codes, which simultaneously direct the print head and print bed and simultaneously switch the flow of the co-reactive composition formed by mixing the thiol and alkenyl components through the ViscoTec extruder.

After the extrusion was initiated, the UV LED lamp was turned on. The liquid thiol-ene formulation was extruded through a static mixing nozzle with an inner diameter of 0.6mm onto the print bed. The seal caps were printed in a continuous spiral pattern using a print head speed of 120 mm/sec and a flow rate of 1.2 mL/min. Under these conditions, the extruded co-reactive composition solidified within 5 seconds of exiting the extruder.

In this example, an Autodesk Inventor is used2019 model the sealing cap as a dome-shaped structure. The diameter of the bottom of the sealing cap is 42.36mm, and the height is 39.89 mm. Three-dimensional printing of the sealing caps cured under these conditions required 9.6 minutes.

A photograph of a three-dimensional printed hermetic cap shell is shown in fig. 4.

Finally, it should be noted that there are alternative ways of implementing the embodiments disclosed herein. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. Furthermore, the claims are not to be limited to the details given herein and are entitled to their full scope and equivalents.