阅读说明：本技术 使用高性能聚烯烃的增材制造方法 (Additive manufacturing process using high performance polyolefins ) 是由 亚历山德罗·贝尔纳迪 亚历山大·迪平托尔·达卢斯 安娜·保拉·德阿泽雷多 莱昂纳多·巴蒂斯塔· 于 2018-12-21 设计创作，主要内容包括：使用增材制造技术制造制品的方法可以包括将聚合物组合物熔融；用一种或多种活化剂将聚合物组合物活化；和将熔融的聚合物组合物沉积以制造制品。制品可以包括聚烯烃组合物的多个打印层,其中聚烯烃组合物由活化的聚烯烃组合物的沉积制备,其中聚烯烃组合物通过一种或多种活化剂活化。(A method of manufacturing an article using additive manufacturing techniques may include melting a polymer composition; activating the polymer composition with one or more activators; and depositing the molten polymer composition to make an article. The article may include multiple printed layers of a polyolefin composition, wherein the polyolefin composition is prepared by deposition of an activated polyolefin composition, wherein the polyolefin composition is activated by one or more activators.)

1. A method of manufacturing an article using additive manufacturing techniques, the method comprising:

melting the polymer composition;

activating the polymer composition with one or more activators; and

depositing the molten polymer composition to make the article.

2. The method of claim 1, wherein the melting comprises extruding the polymer composition.

3. The method of claim 1 or 2, wherein melting the polymer composition and activating the polymer composition are performed simultaneously.

4. The method of any of the above claims, wherein the melting and activating are performed in a printhead of an additive manufacturing machine.

5. The method of claim 1 or 2, wherein depositing the molten polymer composition is performed prior to activating the polymer composition.

6. The method of claim 5, wherein the one or more activating agents comprise ionizing radiation emitted from a radiation source.

7. The method of claim 5, further comprising: applying light in pulses on the deposited polymer composition, wherein the deposited polymer composition comprises the activator, and wherein the pulsed application of light activates the activator by a temperature increase.

8. The method of any of the above claims, further comprising preparing the polymer composition by combining a polymer with one or more activators selected from the group consisting of free radical generators, coupling agents, and crosslinking agents, wherein combining a polymer with one or more activators is performed at a temperature below the activation temperature of the one or more activators, and wherein combining a polymer with one or more activators is performed prior to activating the polymer composition.

9. The method of claim 8, wherein activating the polymer composition comprises increasing the temperature of the combined polymer composition and the one or more activators above the activation temperature of the one or more activators.

10. The method of claim 9, wherein the activation temperature is 190 ℃ or greater.

11. The method of claim 9, wherein the activation temperature is in the range of 190 ℃ to 250 ℃.

12. The method of any of the above claims, further comprising curing the deposited polymer composition with one or more curing agents.

13. The method of claim 12, wherein the curing agent is an unsaturated organosilane.

14. The method of any of the above claims, wherein the one or more activators are selected from the group consisting of: azides, sulfonyl azides, peroxides, aminosilanes, silanes, acrylates, methacrylates, polymeric coupling agents, alpha-beta unsaturated acids, divinylbenzene, diethylene glycol dimethacrylate, diallyl maleate, unsaturated esters and ethers of pentaerythritol, triallyl cyanurate, sulfur donors, p-benzoquinone, hydroquinone, and bisphenols.

15. The method of claim 14, wherein the one or more activators comprise one or more selected from the group consisting of: dicumyl peroxide (DCP), tert-butyl alpha-cumyl peroxide (BCP), di-tert-amyl peroxide (DTAP), alpha' -bis (tert-butyl-peroxy) -1, 3-and 1, 4-diisopropyl-benzene (DTBPIB), 2, 5-bis (tert-butyl-peroxy) -2, 5-Dimethylhexane (DTBPH), di-tert-butyl peroxide (DTBP) and 2, 5-bis (tert-butyl-peroxy) -2, 5-Dimethylhexyne (DTBHY).

16. The method of claim 14, wherein the one or more activators is a bis-sulfonyl azide.

17. The method of claim 14, wherein the one or more activators are added in a weight percent (wt%) of the polymer composition in a range of 0.0001 wt% to 15 wt%.

18. The method of any of the above claims, wherein the polymer composition comprises one or more polyolefins selected from the group consisting of: polyethylene homopolymers, polyethylene copolymers containing one or more C3-C20 olefin comonomers, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, very low density polyethylene, ultra-high molecular weight polyethylene, polypropylene homopolymers, polypropylene copolymers containing one or more C4-C20 olefin comonomers, heterophasic polypropylene and atactic polypropylene.

19. The method of any of the above claims, wherein the polymer composition is a heterophasic polypropylene copolymer comprising a polypropylene matrix phase and a rubber phase, wherein the rubber phase is present in the range of 3 to 70 wt. -%, based on the total weight of the heterophasic polypropylene copolymer.

20. The method of claim 19, wherein the rubber phase comprises ethylene in a range of 15 wt% to 70 wt% based on the weight of the rubber.

21. The method of any of the above claims, wherein the polymer composition is in the form of a filament or a pellet.

22. The method of any of the above claims, wherein depositing the polymer composition comprises a filament deposition modeling technique.

23. The method of any of the above claims, wherein depositing the polymer composition comprises a free form deposition technique.

24. The method of any of the preceding claims, further comprising building a three-dimensional article by repeating the sequence of steps of: activating the polymer composition with one or more activators; melting the polymer composition; and depositing the molten polymer composition.

25. An article made by the method of any one of claims 1 to 24.

26. An article of manufacture, comprising:

a plurality of printed layers of a polyolefin composition, wherein the polyolefin composition is prepared by deposition of an activated polyolefin composition, wherein the polyolefin composition is activated by one or more activators.

27. The article of any one of claims 26, wherein the one or more activators are selected from the group consisting of free radical generators, coupling agents, and crosslinking agents.

28. The article of claim 26, wherein the one or more activators comprise ionizing radiation emitted from a radiation source.

29. The article of claim 28, wherein the one or more activators further comprise an additional activator selected from the group consisting of a free-radical generator, a coupling agent, and a crosslinking agent.

30. The article of claims 26 through 29, wherein the polyolefin composition is coupled with a bis-sulfonyl azide.

Brief Description of Drawings

Fig. 1 is a graph illustrating complex viscosity as a function of angular frequency for a polymer sample according to an embodiment of the present disclosure.

Fig. 2 is a graph illustrating melt strength as a function of draw rate for polymer samples according to embodiments of the present disclosure.

Fig. 3 is a graphical representation of Size Exclusion Chromatography (SEC) results showing weight fraction as a function of molecular weight versus number for polymer samples according to embodiments of the present disclosure.

Fig. 4-7 are microscopic images of 3D printed polymers according to embodiments of the present disclosure.

Fig. 8-10 are graphical representations of physical properties of 3D printed polymers according to the present disclosure.

Detailed description of the invention

In one aspect, embodiments disclosed herein relate to polymer compositions having particular applications for additive manufacturing applications, particularly those that use material extrusion to deposit molten polymer. The polymer composition according to the present disclosure may comprise a polymer component and an activator that initiates the formation of branches and crosslinks that enhance the mechanical properties of the polymer component during article manufacturing. The method according to the present disclosure may use an activator to change the surface energy of the polymer and to change the adhesion to different substrates and the adhesion between printed layers, and may extend the field of polymers that may be used in material extrusion processes.

Material Extrusion (ME) is a variant of additive manufacturing that selectively extrudes a polymer melt through a nozzle or other orifice and deposits the polymer in successive layers onto a substrate to create a three-dimensional structure. One example of a common ME process is Fused Deposition Modeling (FDM) in which an extrusion head heats a plastic filament, producing a polymer melt that is extruded through a nozzle in a controlled pattern onto a print substrate. Other ME processes include free form printing, where a polymer resin is melted and deposited through a nozzle onto a print substrate in the form of droplets (rather than a molten polymer stream).

In general, higher Molecular Weight (MW) polyolefins are generally preferred for product manufacture in many applications because of their improved mechanical properties and durability when compared to low MW polyolefins. However, during additive manufacturing, higher MW polyolefins typically exhibit higher viscosities under melt conditions, which may negatively impact extrusion performance due to poor polymer chain diffusion and interlayer adhesion. As a result, printed articles prepared from high MW polyolefins exhibit lower mechanical resistance when compared to injection molded articles of the same material. On the other hand, low MW polymers exhibit good coalescence and chain diffusion properties during additive manufacturing, but form parts with low mechanical properties and lead to a higher incidence of shrinkage of the final geometry due to polymer crystallization during the cooling phase.

The polymer compositions according to the present disclosure may address these issues by incorporating one or more activators that react with (activate) the polymer components in the mixture. Activation creates reactive sites on the polymer component that form cross-linked and branched structures that enhance the mechanical properties of the composition for material extrusion applications. For example, while low MW polymers may exhibit good chain diffusion and extrusion properties, the materials produce articles with poor mechanical properties during the material extrusion process. However, by activating the polymer with an activator, the chain extension and branching reactions improve the dimensional stability of the extruded material and avoid or reduce the warpage and shrinkage characteristics of low MW polymers.

In one or more embodiments, the polymer composition may include an activator that is activated during the additive manufacturing process. Activators according to the present disclosure include chemical activators and physical activators. Chemical activators include agents that activate under manufacturing conditions, such as at elevated temperature or pressure, and react with the polymeric components of the composition either directly or by generating reactive species, such as free radicals. Examples of such chemical activators include, for example, coupling agents, crosslinking agents, free radical generating agents, and the like. The chemical activator may be "activated" by raising the temperature above a predetermined activation temperature (depending on the activator). The activated polymer composition is then deposited as a melt onto a surface or continuous layer, and the sequence is repeated until the printed article is completed.

To prevent activation or decomposition of the composition prior to use, the polymer composition may be combined with one or more activators at a temperature below the activation temperature. In addition, the melting and extrusion steps may also be performed at temperatures below the activation temperature to maintain acceptable viscosity and chain diffusion levels. For example, in an FDM process, active components can be added during extrusion for the manufacture of filaments. When the filaments are fed in the FDM printer, the liquefier temperature is set to the activation temperature (above) and polymer activation is performed at the time of printing the part. In a free form process, the activator may be combined with or coated with the polymer pellet feedstock or added to an extrusion process where the polymer components are melted prior to the polymer dispensing step. Activation of the polymer composition is followed during deposition while the extruded polymer melt is heated at the print head.

In one or more embodiments, the activator can be ionizing radiation from a radiation source, used alone or in combination with one or more chemical activators, that activate the polymer component of the polymer composition by generating free radicals capable of initiating chain extension and/or crosslinking during extrusion manufacturing of the article. Methods employing ionizing radiation as an activator may include exposing the deposited molten polymeric material to a radiation source, such as a lamp or laser, that activates the coupling agent and initiates conversion of the printed polymer.

In one or more embodiments, the processing of the polymer composition, including mixing, extrusion, and melting, can be performed below the activation temperature of a given activator, where little activation occurs. Activation of the polymer composition can then be controlled using residence time, temperature control, shear, and exposure to radiation before, during, or after deposition onto a substrate or article.

In one or more embodiments, the printed article may be subjected to additional treatments in post-treatment to fully convert any reactive species, such as free radicals or unreacted coupling agents. In some embodiments, a post-processing stage may be employed at the completion of the printed article or after the printing of each layer. Post-treatment may include treatment with additional chemical curing agents such as organosilanes. Further, post-processing may include the use of physical methods that heat or pulse the printed article for a period of time sufficient to convert any residual reactive species and increase chain diffusion between the printed particles and the layer. The physical post-treatment may include a secondary laser, a ceramic heater, a quartz heater, or an ultrasonic device.

Polymer component

In one or more embodiments, the polymer composition may be prepared from a polyolefin polymer or copolymer that is reacted with an activator to introduce one or more branches or crosslinks. In some embodiments, the polyolefin component of the polymer composition may form a polymer matrix phase surrounding other components, such as the rubber internal phase and/or other additives. In some embodiments, the polymer component of the polymer composition may include a combination of one or more polymers or copolymers prepared by a co-polymerization or a post-polymerization in a reactor.

The polyolefin may comprise a homopolymer, a random copolymer, or a heterophasic polymer composition. Polyolefins include polymers and copolymers of C2 to C20 olefins such as ethylene, propylene, butene, pentene, hexene, heptene, octene, branched olefins, unsaturated olefins, and the like. Polyolefins according to the present disclosure may include polyethylene, polyethylene copolymers containing one or more olefin comonomers, copolymers of ethylene with one or more C3-C20 alpha-olefins, high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, very low density polyethylene, ultra high molecular weight polyethylene, and polypropylene such as polypropylene homopolymer, polypropylene copolymers containing one or more olefin comonomers, copolymers of propylene with ethylene or one or more C4-C20 alpha-olefins, heterophasic polypropylene, atactic polypropylene. The polypropylene according to the present disclosure may be atactic or may have isotactic or syndiotactic stereoregularity. The polymer composition may also include polymers produced from petroleum-based monomers, monomers of biological origin, and post-consumer recycled polyolefins.

In one or more embodiments, the polymer composition may include a polypropylene polymer having a weight percent (wt%) of a C2 to C20 polyolefin comonomer in a range from a lower limit selected from 0.5 wt%, 1 wt%, or 5 wt% to an upper limit selected from 2.5 wt%, 5 wt%, or 10 wt%, wherein any lower limit may be combined with any upper limit.

In addition to the above polyolefins, other polymer compositions that react with activators according to the present disclosure may be used. For example, the polymer composition may also comprise a polymer component prepared from other polymers and copolymers including halogenated polymers such as polyvinyl chloride, polyesters such as polylactic acid and polyglycolic acid, polyamides such as polyamide 12, polyamide 6, polyamide 8, polyamide 11, polyamide 66, and thermoplastics such as Acrylonitrile Butadiene Styrene (ABS).

Internal rubber phase

In one or more embodiments, the polymer compositions according to the present disclosure include a heterophasic polymer composition having an internal rubber phase dispersed in a polymer matrix phase. In some embodiments, the polymer composition may include a polymer composition classified as an Impact Copolymer (ICP).

In one or more embodiments, rubbers suitable for use as the inner rubber phase include homopolymers and copolymers with one or more monomers. In some embodiments, the rubber may include graft copolymers such as maleated ethylene-propylene copolymers, and terpolymers of ethylene and propylene with non-conjugated dienes such as 5-ethylidene-2-norbornene, 1, 8-octadiene, 1, 4-hexadiene, cyclopentadiene, and the like. Other polymers may include low density polyethylene, ethylene propylene rubber, poly (ethylene-methyl acrylate), poly (ethylene-acrylate), ethylene propylene diene rubber (EPDM), vinyl silicone rubber (VMQ), fluorosilicone rubber (FVMQ), nitrile rubber (NBR), acrylonitrile-butadiene-styrene (ABS), Styrene Butadiene Rubber (SBR), styrene-ethylene rubber, styrene-butadiene-styrene block copolymers (SBS and SEBS), polybutadiene rubber (BR), styrene-isoprene-styrene block copolymers (SIS), partially hydrogenated acrylonitrile butadiene (HNBR), Natural Rubber (NR), synthetic polyisoprene rubber (IR), neoprene rubber (CR), polychloroprene, bromobutyl rubber, chlorobutyl rubber, polyurethane, elastomeric polyolefins that are ethylene-octene copolymers, and combinations thereof.

In some embodiments, the inner rubber phase may be an ethylene-propylene rubber (EPR), which may include an EPR having one or more comonomers in addition to ethylene and propylene. Other comonomers may include, for example, alpha olefins such as 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, and the like.

In one or more embodiments, the polymer composition may include a heterophasic polymer having a polymer matrix phase and an internal rubber phase present at a weight percent (wt%) of the branched polymer composition within a range from a lower limit selected from any of 2 wt%, 3 wt%, 5 wt%, and 10 wt% to an upper limit selected from any of 50 wt%, 60 wt%, 70 wt%, and 75 wt%, wherein any lower limit may be paired with any upper limit.

In one or more embodiments, the polymer composition may include a heterophasic polymer having an internal rubber phase prepared from ethylene and a C3 to C8 polyolefin comonomer, wherein the ethylene is present in a weight percent (wt%) of the internal rubber phase within a range from a lower limit selected from any of 5 wt%, 10 wt%, 15 wt%, and 20 wt% to an upper limit selected from any of 50 wt%, 60 wt%, 70 wt%, and 75 wt%, wherein any lower limit may be paired with any upper limit.

Chemical activator

In one or more embodiments, the polymer composition may include one or more chemical activators to form intra-and inter-chain covalent bonds between chains of the polymer component of the polymer composition. Activators according to the present disclosure may include chemical activators such as coupling agents, free radical generating agents, and crosslinking agents that are combined with the polymer composition during the ME process prior to activation. In one or more embodiments, multiple types of activators may be used. For example, in some embodiments, a combination of activators may be used, such as a coupling agent in combination with a free radical generating agent, and a chemical activator may be combined with ionizing radiation.

In one or more embodiments, the polyolefin composition may be grafted with a coupling or curing agent that is activated during the melting and/or sintering step prior to use in the additive manufacturing technique. In some embodiments, stoichiometry or multiple orthogonal functional groups may be used to control the level of crosslinking between the coupling agent and the polyolefin to maintain favorable viscosity profile characteristics. For example, the polyolefin may be copolymerized or grafted with a bifunctional coupling or curing agent having a first olefinic functional group covalently bonded to the polyolefin backbone, while a second functional group, such as a silane group, is activated during subsequent powder-based fusion processes upon exposure to moisture or elevated temperature.

The polymer compositions according to the present disclosure may be modified with one or more activators at any step of the material extrusion process by increasing the temperature of the composition above the activation temperature. Activation may be performed at any step, including during the melting process, during deposition onto the substrate, or after deposition.

In some embodiments, the activator can have an activation temperature in a range having a lower limit selected from any one of 150 ℃, 175 ℃, and 190 ℃ to an upper limit selected from any one of 200 ℃, 250 ℃, and 300 ℃, wherein any lower limit can be paired with any upper limit. In some embodiments, an activator according to the present disclosure may have an activation temperature of 190 ℃ or greater; or an activation temperature in the range of 190 ℃ to 250 ℃. However, although a plurality of temperature ranges is provided, the activation temperature may depend more or less on the nature of the activator and the presence of the catalyst or applied radiation source.

In one or more embodiments, the activator can be included in a weight percent (wt%) of the polymer composition within a range from a lower limit selected from any of 0.0001 wt%, 0.001 wt%, 0.1 wt%, and 1 wt% to an upper limit selected from any of 2.5 wt%, 3 wt%, 5 wt%, 10 wt%, and 15 wt%, where any lower limit can be paired with any upper limit. However, while ranges are provided for the above chemical activators, it is also contemplated that the concentration of one or more activators may be more or less dependent on the particular application and article design criteria.

Coupling agent

In one or more embodiments, the polyolefin composition may include one or more coupling agents that react with the polyolefin component to form one or more intra-and inter-chain covalent bonds between the polymer chains. Coupling agents according to the present disclosure include compounds containing at least two reactive groups capable of forming a bond with a main chain or a side chain of a constituent polymer in a branched polymer composition.

In one or more embodiments, the coupling agent may include sulfonyl azides, polysulfonyl azides, phosphazene azides, diazoalkanes, formyl azides, dienes, geminally substituted methylenes, polymeric coupling agents, metal carbenes, peroxides, aminosilanes, silanes, acrylates, methacrylates, and α - β unsaturated acids, among others.

The polysulfonyl azides according to the present disclosure may have the general formula X-R-X, where each X is SO₂N₃And R is a carbon chain which may be saturated or unsaturated, cyclic or acyclic, aromatic or non-aromatic, the polysulfonyl azide may contain one or more heteroatoms including oxygen, nitrogen, sulfur or silicon and one or more additional azide functional groups. Suitable coupling agents may include R as an aryl, alkyl, arylalkylaryl, arylalkylsilane, siloxane, or heterocyclic group, as well as other groups that are inert and separate the sulfonyl azide groups described. In some embodiments, R may include at least one aryl group, most preferably at least two aryl groups between sulfonyl groups (e.g., when R is 4,4 'diphenyl ether or 4,4' -biphenyl).

The polysulfonyl azide may include: 4,4' -oxydiphenylsulfonyl azide, naphthylene bis (sulfonyl azide), 1, 5-pentane bis (sulfonyl azide), 1, 8-octane bis (sulfonyl azide), 1, 10-decane bis (sulfonyl azide), 1, 10-octadecane bis (sulfonyl azide), 1-octyl-2, 4, 6-benzenetris (sulfonyl azide), 4' -bis (benzenesulfonyl azide), 1, 6-bis (4 ' -sulfonylazidophenyl) hexane, 2, 7-naphthalene bis (sulfonyl azide) and mixed sulfonyl azides of chlorinated aliphatic hydrocarbons containing an average of 1 to 8 chlorine atoms and about 2 to 5 sulfonyl azide groups per molecule, as well as mixtures thereof. In some embodiments, the coupling agent may include bis-sulfonyl azides, polysulfonyl azides such as oxy-bis (4-sulfonylazidobenzene), 2, 7-naphthalene bis (sulfonylazido), 4 '-bis (sulfonylazido) biphenyl, 4' -oxybis (benzenesulfonylazide) and bis (4-sulfonylazidophenyl) methane, and mixtures thereof.

In one or more embodiments, the coupling agent may comprise a polymeric coupling agent. Polymeric coupling agents according to the present disclosure may include polyolefins having reactive groups at the terminal ends and/or on the backbone of the polyolefin chain. The polyolefin backbone may be linear or branched, have more than two termini, and the reactive groups on the polymeric coupling agent may be the same or mixed. In one or more embodiments, the polymeric coupling agent may have R (X)_nR 'wherein R and R' are independently selected from reactive groups that may include peroxides, alkylboranes, halogens, thiols, amines, amides, aldehydes, alcohols, carboxylic acids, esters, isocyanates, silanes, phosphorous-containing groups, dithioesters, dithiocarbamates, dithiocarbonates, trithiocarbonates, alkoxyamines, arylsulfonyl halides, arylsulfonyl azides, phosphoryl azides, vinyls, alkylvinyls, vinylenes, arylvinyls, dienes, alkyl azides, or derivatives thereof; (X) is a polyolefin having n olefin units, wherein the polyolefin may be linear or branched, saturated or unsaturated, and may contain one or more heteroatoms such as fluorine, chlorine, bromine, iodine, oxygen, sulfur, selenium, nitrogen, phosphorus, silicon and boron; and n may be an integer in the range of 2 to 1000.

Any polyolefin may be used to prepare the modified polyolefin of the polymeric coupling agent. Polyolefins include polymers and copolymers prepared from linear or branched olefins having from 2 to 20 carbon atoms. The polyolefin used to prepare the polymeric coupling agent may be a homopolymer synthesized from a single olefin or a copolymer synthesized from two or more olefins. For example, the polyolefin used to prepare the polymeric coupling agent may be polyethylene; polypropylene; and copolymers of ethylene and propylene.

Crosslinking agent

In one or more embodiments, the activator may include a crosslinker, which is a bifunctional species having functional groups that can react with the polymer component of the polymer composition to form one or more intra-or inter-chain bonds with the backbone of the polymer component. The functional groups may include functional groups such as vinyl, allyl, acrylic, methacrylic, sulfur, thiol, michael acceptors, and mixtures thereof. Crosslinkers according to the present disclosure may include divinylbenzene, diethylene glycol dimethacrylate, diallyl maleate, unsaturated esters and ethers of pentaerythritol, triallylcyanurate, sulfur donors such as thiourea and thiourea derivatives, p-benzoquinone, hydroquinone, bisphenols, and the like. In some embodiments, cross-linking agents according to the present disclosure may include divinylbenzene, diethylene glycol dimethacrylate, diallyl maleate, unsaturated esters and ethers of pentaerythritol, triallyl cyanurate, sulfur donors (thiourea and thiourea derivatives), p-benzoquinone, hydroquinone, and bisphenol.

Free radical generating agent

In one or more embodiments, the activator may include one or more free radical generating agents capable of generating free radicals that react with the polymer components of the polymer composition to form branches and crosslinks in the polymer structure. Free radical generators according to the present disclosure may include one or more peroxides capable of generating free radicals during polymer processing to promote curing. Peroxides may include dicumyl peroxide (DCP), t-butyl α -cumyl peroxide (BCP), di-t-amyl peroxide (DTAP), α' -bis (t-butyl-peroxy) -1, 3-and 1, 4-diisopropyl-benzene (DTBPIB), 2, 5-bis (t-butyl-peroxy) -2, 5-Dimethylhexane (DTBPH), di-t-butyl peroxide (DTBP) and 2, 5-bis (t-butyl-peroxy) -2, 5-Dimethylhexyne (DTBHY).

Other peroxides may include: benzoyl peroxide, di-tert-butyl peroxide, tert-butylcumyl peroxide, tert-butyl 3,5, 5-trimethylhexanoate peroxide, tert-butyl peroxybenzoate, 2-ethylhexyl tert-butylperoxycarbonate, 2, 5-dimethyl-2, 5-di (tert-butylperoxy) hexane, 1-di (tert-butylperoxy) -3,3, 5-trimethylcyclohexane, 2, 5-dimethyl-2, 5-di (tert-butylperoxy) hexyne-3, 3,5,7, 7-pentamethyl-1, 2, 4-trioxepane, butyl 4, 4-di (tert-butylperoxy) valerate, di (2, 4-dichlorobenzoyl) peroxide, di (4-methylbenzoyl) peroxide, Di (t-butylperoxyisopropyl) benzene peroxide, 2, 5-di (cumylperoxy) -2, 5-dimethylhexane, 2, 5-di (cumylperoxy) -2, 5-dimethylhexyne-3, 4-methyl-4- (t-butylperoxy) -2-pentanol, 4-methyl-4- (t-amylperoxy) -2-pentanol, 4-methyl-4- (cumylperoxy) -2-pentanol, 4-methyl-4- (t-butylperoxy) -2-pentanone, 4-methyl-4- (t-amylperoxy) -2-pentanone, 4-methyl-4- (cumylperoxy) -2-pentanone, 2-methyl-4- (cumylperoxy) -2-pentanone, 2-methyl-5-di (cumylperoxy) -2, 5-dimethylhexane, 2, 5-dimethyl-2, 5-di (t-butylperoxy) hexane, 2, 5-dimethyl-2, 5-di (t-amylperoxy) hexane, 2, 5-dimethyl-2, 5-di (t-butylperoxy) hexyne-3, 2, 5-dimethyl-2, 5-di (t-amylperoxy) hexyne-3, 2, 5-dimethyl-2-t-butylperoxy-5-hydroperoxyhexane, 2, 5-dimethyl-2-cumylperoxy-5-hydroperoxyhexane, 2, 5-dimethyl-2-t-amylperoxy-5-hydroperoxyhexane, m/p-alpha, alpha-di [ (t-butylperoxy) isopropyl ] benzene, n-butyl peroxy-ethyl peroxy-5-hydroperoxyhexane, m-p-alpha, alpha-di [ (t-butylperoxy) isopropyl ], 1,3, 5-tris (t-butylperoxyisopropyl) benzene, 1,3, 5-tris (t-amylperoxy isopropyl) benzene, 1,3, 5-tris (cumylperoxyisopropyl) benzene, bis [1, 3-dimethyl-3- (t-butylperoxy) butyl ] carbonate, bis [1, 3-dimethyl-3- (t-amylperoxy) butyl ] carbonate, bis [1, 3-dimethyl-3- (cumylperoxy) butyl ] carbonate, di-t-amylperoxide, t-amylcumylperoxide, t-butylisopropenylcumylperoxide, 2,4, 6-tris (butylperoxy) -s-triazine, 1,3, 5-tris [1- (t-butylperoxy) -1-methylethyl ] benzene, 1,3, 5-tris [ (t-butylperoxy) -isopropyl ] benzene, 1, 3-dimethyl-3- (t-butylperoxy) butanol, 1, 3-dimethyl-3- (t-amylperoxy) butanol, bis (2-phenoxyethyl) peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, dimyristyl peroxydicarbonate, dibenzyl peroxydicarbonate, di (isobornyl) peroxydicarbonate, 3-cumylperoxy-1, 3-dimethylbutyl methacrylate, 3-t-butylperoxy-1, 3-dimethylbutyl methacrylate, 3-t-amylperoxy-1, 3-dimethylbutyl methacrylate, tris (1, 3-dimethyl-3-t-butylperoxybutoxy) vinylsilane, 1, 3-dimethyl-3- (tert-butylperoxy) butyl N- [1- {3- (1-methylvinyl) -phenyl } -1-methylethyl ] carbamate, 1, 3-dimethyl-3- (tert-amylperoxy) butyl N- [1- {3- (1-methylvinyl) -phenyl } -1-methylethyl ] carbamate, 1, 3-dimethyl-3- (cumylperoxy) butyl N- [1- {3- (1-methylvinyl) -phenyl } -1-methylethyl ] carbamate, 1-di (tert-butylperoxy) -3,3, 5-trimethylcyclohexane, 1-di (tert-butylperoxy) cyclohexane, methyl-ethyl-1-carbamate, methyl-1-propyl-1-methyl-3-propyl-3-carbamate, methyl-1-propyl-carbonate, methyl, N-butyl 4, 4-di (tert-amylperoxy) valerate, ethyl 3, 3-di (tert-butylperoxy) butyrate, 2-di (tert-amylperoxy) propane, ethyl 3,6,6,9, 9-pentamethyl-3-ethoxycarbonylmethyl-1, 2,4, 5-tetraoxacyclononane, n-butyl 4, 4-bis (tert-butylperoxy) valerate, ethyl 3, 3-di (tert-amylperoxy) butyrate, benzoyl peroxide, OO-tert-butyl-O-hydro-monoperoxy-succinate, OO-tert-amyl-O-hydro-monoperoxy-succinate, 3,6, 9-triethyl-3, 6, 9-trimethyl-1, 4, 7-triperoxynonane (or cyclic trimer of peroxides) methyl ethyl ketone, Methyl ethyl ketone peroxy cyclic dimer, 3,6,6,9, 9-hexamethyl-1, 2,4, 5-tetraoxacyclononane, 2, 5-dimethyl-2, 5-di (benzoylperoxy) hexane, tert-butyl peroxybenzoate, tert-butyl peroxyacetate, tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxybenzoate, tert-amyl peroxyacetate, tert-butyl peroxyisobutyrate, 3-hydroxy-1, 1-dimethyl-tert-butyl peroxy-2-ethylhexanoate, OO-tert-amyl-O-hydro-monoperoxy-succinate, OO-tert-butyl-O-hydro-monoperoxy-succinate, di-tert-butyl diperoxyphthalate, peroxy (3, tert-butyl 3, 5-trimethylhexanoate), 1, 4-bis (tert-butylperoxycarboxyl) cyclohexane, tert-butyl peroxy 3,5, 5-trimethylhexanoate, tert-butyl peroxy (cis-3-carboxy) propionate, allyl 3-methyl-3-tert-butylperoxybutyrate, OO-tert-butyl-O-isopropyl monoperoxycarbonate, OO-tert-butyl-O- (2-ethylhexyl) monoperoxycarbonate, 1,1, 1-tris [2- (tert-butylperoxy-carbonyloxy) ethoxymethyl ] propane, 1,1, 1-tris [2- (tert-amylperoxy-carbonyloxy) ethoxymethyl ] propane, 1,1, 1-tris [2- (cumylperoxy-carbonyloxy) ethoxymethyl ] propane, OO-t-amyl-O-isopropyl monoperoxycarbonate, bis (4-methylbenzoyl) peroxide, bis (3-methylbenzoyl) peroxide, bis (2-methylbenzoyl) peroxide, didecanoyl peroxide, dilauroyl peroxide, 2, 4-dibromo-benzoyl peroxide, succinic peroxide, dibenzoyl peroxide, bis (2, 4-dichloro-benzoyl) peroxide, dicetyl peroxydicarbonate, and combinations thereof. The peroxide may also include azo-peroxide initiators including mixtures of peroxides with azodinitrile compounds such as 2,2 ' -azobis (2-methyl-valeronitrile), 2 ' -azobis (2-methyl-butyronitrile), 2 ' -azobis (2-ethyl-valeronitrile), 2- [ (1-cyano-1-methylpropyl) azo ] -2-methyl-valeronitrile, 2- [ (1-cyano-1-ethylpropyl) azo ] -2-methyl-butyronitrile, 2- [ (1-cyano-1-methylpropyl) azo ] -2-ethyl and the like.

For reactions between free radicals generated by the free radical generating agent, macromolecular free radicals formed by the reaction of the polymer in the activated polymer composition with free radicals may undergo competitive crosslinking and chain scission reactions. For example, polyethylene macromolecular radicals may have a higher probability of crosslinking, while macromolecular radicals formed from polypropylene have a higher probability of chain scission. The difference in reactivity is generally due to the fact that: polymers such as polypropylene generate tertiary carbon-centered radicals that are more stable than secondary carbon-centered radicals formed in polymers such as polypropylene. However, in ethylene-propylene copolymers with higher ethylene content, the crosslinking reaction of the polypropylene radicals increases relative to the chain scission reaction. In some embodiments, the crosslinking of tertiary carbon-centered polymers, such as polypropylene, with a free radical source can be controlled or altered by adjusting the peroxide concentration or temperature. For example, crosslinking by peroxide generated free radicals in polypropylene can be achieved by using high peroxide concentrations and low reaction temperatures that minimize chain scission reactions.

Physical activator-ionizing radiation

The method according to the present disclosure may incorporate one or more radiation sources to generate ionizing radiation of an intensity that causes an increase in temperature in the polymer composition. In some embodiments, the radiation source may have a variable intensity that may span from an intensity suitable to initiate melting of the polyolefin composition to an intensity suitable to heat the polyolefin composition above the activation temperature of the coupling agent.

Radiation sources may include sources used in commercial additive manufacturing applications and include lamps and lasers operating in the entire spectrum, such as Infrared (IR), Ultraviolet (UV), gamma and X-rays, electron beams, and the like. In one or more embodiments, the radiation source can be focused on the polyolefin composition during melting and/or sintering, and the radiation source can be stationary or mobile.

Curing agent

The polymer compositions according to the present disclosure may be post-treated with one or more curing agents after activation and deposition during the material extrusion process. Curing agents according to the present disclosure may include organosilanes containing functional groups that can react with the polymer composition, including vinyl, epoxy, acryloxy, methacryloxy, amino, ureide, mercapto, isocyanate, isocyanurate, and the like. In one or more embodiments, unsaturated organosilanes such as vinyl triethoxysilane, vinyl-tris- (β -methoxyethoxy) silane, methacryloxypropyl trimethoxysilane, γ -amino-propyltriethoxysilane, 3-thiocyanatopropyl-triethoxysilane, γ -mercaptopropyl trimethoxysilane, and the like, may be included.

In one or more embodiments, an unsaturated organosilane may be grafted to the polymer component of the polymer composition. When the grafted polymer is exposed to ambient humidity or aqueous fluids during the curing step, hydrolysis of the grafted silane groups produces reactive silanes that condense and produce siloxane crosslinking in the cured polymer.

In one or more embodiments, the curing agent may be included in a weight percent (wt%) of the polymer composition within a range from a lower limit selected from any of 0.0001 wt%, 0.001 wt%, 0.1 wt%, and 1 wt% to an upper limit selected from any of 2.5 wt%, 3 wt%, 5 wt%, and 10 wt%, where any lower limit may be paired with any upper limit.

Additive agent

The polymer compositions according to the present disclosure may comprise additives that change various physical and chemical properties when added to the polymer composition during blending, including one or more polymer additives such as flow lubricants, antistatic agents, clarifiers, nucleating agents, beta-nucleating agents, slip agents (slip agents), antioxidants, antacids, light stabilizers such as HALS, IR absorbers, silica, titanium dioxide, silicon dioxide, organic dyes, organic pigments, inorganic dyes, and inorganic pigments.

Physical Properties

In one or more embodiments, the polyethylene composition, prior to reaction with the coupling agent, may have an initial Melt Flow Index (MFI) at 190 ℃ and 2.16kg, as determined according to astm d1238, in a range having a lower limit selected from any one of 1g/10min, 5g/10min, 10g/10min, and 15g/10min to an upper limit selected from any one of 50g/10min, 100g/10min, 500g/10min, and 600g/10min, wherein any lower limit may be paired with any upper limit. In one or more embodiments, the polypropylene composition, prior to reaction with the coupling agent, can have an initial Melt Flow Index (MFI) at 230 ℃ and 2.16kg, as determined according to ASTM D1238, in a range having a lower limit selected from any one of 1g/10min, 5g/10min, 10g/10min, and 15g/10min to an upper limit selected from any one of 100g/10min, 500g/10min, 600g/10min, and 700g/10min, wherein any lower limit can be paired with any upper limit.

In one or more embodiments, the polyethylene composition produced from the reaction with the coupling agent may have a final Melt Flow Index (MFI) at 190 ℃ and 2.16kg, as determined according to ASTM D1238, within a range having a lower limit selected from any one of 0.1g/10min, 0.2g/10min, 0.5g/10min, and 1g/10min to an upper limit selected from any one of 5g/10min, 10g/10min, 20g/10min, and 50g/10min, wherein any lower limit may be paired with any upper limit. In one or more embodiments, the polypropylene composition produced from the reaction with the coupling agent may have a final Melt Flow Index (MFI) at 230 ℃ and 2.16kg, as determined according to ASTM D1238, in a range having a lower limit selected from any one of 0.2g/10min, 0.5g/10min, 1g/10min, and 2g/10min to an upper limit selected from any one of 10g/10min, 20g/10min, 50g/10min, and 60g/10min, wherein any lower limit may be paired with any upper limit.

In one or more embodiments, the initial intrinsic viscosity of a polymer according to the present disclosure prior to reaction with a coupling agent, as measured with decalin (decalin) solvent (or decalin (decalin)) at 135 ℃, may be in a range having a lower limit selected from 3dL/g, 5dL/g, and 10dL/g to an upper limit selected from 15dL/g, 20dL/g, 40dL/g, and 50dL/g, wherein any lower limit may be paired with any upper limit.

In one or more embodiments, the polymer composition may exhibit a molecular weight after reaction with the coupling agent selected from 0.9g/cm³、0.91g/cm³And 0.92g/cm³The lower limit of any one of (a) to (b) is selected from 0.95g/cm³、0.97g/cm³And 0.98g/cm³A final density according to ASTM D792 within a range of an upper limit of any one of, wherein any lower limit can be paired with any upper limit.

Applications of

Methods according to the present disclosure may be used for a variety of additive manufacturing techniques, including FDM and free-form deposition. Additive manufacturing systems according to the present disclosure include any system that prints, builds, or manufactures 3D parts and/or support structures. The additive manufacturing system may be a stand-alone unit, a sub-unit of a larger system or production line, and/or may include other non-additive manufacturing features, such as subtractive manufacturing features, pick and place features, two-dimensional printing features, and the like.

Articles that may be formed include, for example, packaging, rigid and flexible containers, household appliances, molded articles such as caps, bottles, cups, bags, labels, tubes, canisters, cartridges, sinks, medical devices, shelving units, and the like. In particular, any article conventionally made (using conventional manufacturing techniques) from the polymer compositions of the present disclosure may instead be manufactured by additive manufacturing.

The use of the polymer composition according to the present disclosure may provide higher flexibility in products produced by additive manufacturing processes. In particular, for example, articles produced by additive manufacturing may have a lower flexural modulus and superior fatigue resistance compared to PLA or ABS.

Examples