阅读说明：本技术 可固化组合物、由其制得的制品，及其制造和使用方法 (Curable compositions, articles made therefrom, and methods of making and using the same ) 是由 姚犁 迈克尔·A·克洛普 马修·J·克里格 韦恩·S·莫尼 马里奥·A·佩雷斯 吴爽 童 于 2019-03-25 设计创作，主要内容包括：本发明公开了一种可固化组合物,该可固化组合物包含：第一部分,所述第一部分包含环氧树脂；以及第二部分,所述第二部分包含多官能的含官能硫醇的化合物。该可固化组合物还包含无机填料,所述无机填料以基于可固化组合物的总重量计至少20重量％的量存在。所述多官能的含官能硫醇的化合物在其主链中包含醚。(Disclosed is a curable composition comprising: a first part comprising an epoxy resin; and a second part comprising a multifunctional thiol-containing compound. The curable composition further includes an inorganic filler present in an amount of at least 20 weight percent based on the total weight of the curable composition. The multifunctional thiol-containing compound comprises an ether in its backbone.)

1. A curable composition comprising:

a first part comprising an epoxy resin; and

a second part comprising a multifunctional thiol-containing compound; and

an inorganic filler present in an amount of at least 20 weight percent based on the total weight of the curable composition,

wherein the multifunctional thiol-containing compound comprises an ether in its backbone.

2. The curable composition of claim 1, wherein one or more of the functional thiols is a terminal thiol.

3. The curable composition of claim 1, wherein the multifunctional thiol-containing compound is represented by the formula:

wherein R is an aliphatic hydrocarbon, n is 0 to 20, and m is 2 to 4.

4. The curable composition of claim 1, wherein the multifunctional thiol-containing compound is represented by one of the following formulas:

wherein each of R1, R2, and R3 is independently an alkyl group having 1 to 4 carbon atoms or hydrogen, and n is 0 to 20.

5. The curable composition of any one of the preceding claims, wherein the epoxy resin comprises an internally flexible bisphenol epoxy resin.

6. The curable composition of claim 5, wherein the internally flexible bisphenol epoxy resin is represented by the formula:

wherein Ar is bisphenol A, bisphenol F, bisphenol Z, or a mixture thereof.

7. The curable composition of any one of the preceding claims, wherein the epoxy resin comprises phosphonic acid groups in its backbone.

8. The curable composition of any one of the preceding claims, further comprising a silane coupling agent.

9. The curable composition of claim 8, wherein the silane coupling agent comprises an amine-terminated silane coupling agent.

10. The curable composition of claim 8, wherein the silane coupling agent comprises a thiol-terminated silane coupling agent.

11. The curable composition of claim 8, wherein the silane coupling agent comprises an epoxy-terminated silane coupling agent.

12. The curable composition of any one of the preceding claims, further comprising a catalyst.

13. The curable composition of claim 12, wherein the catalyst comprises a basic catalyst.

14. The curable composition of claim 13, wherein the basic catalyst is represented by one of the following formulas:

15. the curable composition of claim 12, wherein the catalyst comprises a lewis acid catalyst.

16. The curable composition of claim 15, wherein the lewis acid catalyst comprises calcium triflate, calcium nitrate, or a tin catalyst.

17. The curable composition of any one of the preceding claims, wherein epoxy resin is present in the curable composition in an amount of at least 20 weight percent based on the total weight of unfilled curable composition.

18. The curable composition of any one of the preceding claims, wherein multifunctional functional thiol-containing compound is present in the curable composition in an amount of at least 10 weight percent based on the total weight of the unfilled curable composition.

19. The curable composition of any one of the preceding claims, wherein the curable composition, after curing, has (i) an elongation at break of greater than 5.5%, and (ii) 5N/mm on untreated aluminum²-20N/mm²Lap shear strength of (a).

20. The curable composition of any one of the preceding claims, wherein the curable composition, after curing, has a tensile strength of from 1N/mm2 to 16N/mm 2.

21. The curable composition of any one of the preceding claims, wherein the curable composition retains at least 70% of lap shear strength after curing after humidity testing according to PR308.2 test method.

22. The curable composition of any one of the preceding claims, wherein the curable composition after curing exhibits a decrease in tensile strength of less than 30% after humidity testing according to PR308.2 test method.

23. The curable composition of any one of the preceding claims, wherein the curable composition exhibits a gel time at room temperature of no more than 60 minutes as determined on a Discovery HR-3 rheometer equipped with a forced convection oven attachment (TA Instruments, Wood Dale, IL, US) with an oscillating shear rheometer measurement at 100rad/s angular frequency at 1% strain.

24. The curable composition according to any one of the preceding claims, wherein the curable composition has a thermal conductivity of at least 1.0W/(m x K) after curing.

25. The curable composition of any one of the preceding claims, wherein the inorganic filler is present in an amount of at least 20 weight percent based on the total weight of the curable composition.

26. The curable composition of any one of the preceding claims, wherein the inorganic filler is present in an amount of at least 50 weight percent based on the total weight of the curable composition.

27. The curable composition of any one of the preceding claims, wherein the inorganic filler comprises alumina.

28. The curable composition of any one of the preceding claims, wherein the inorganic filler comprises spherical alumina particles and hemispherical alumina particles.

29. The curable composition of any one of the preceding claims, wherein the inorganic filler comprises silane surface treated particles.

30. The curable composition of any one of the preceding claims, wherein the inorganic filler comprises ATH.

31. An article comprising a cured composition, wherein the cured composition is a reaction product of the curable composition of any one of the preceding claims.

32. The article of claim 31, wherein the cured composition has a thickness of between 5 microns to 10000 microns.

33. The article of any one of claims 31 to 32, further comprising a substrate having a surface, wherein the cured composition is disposed on the surface of the substrate.

34. The article of claim 33, wherein the substrate is a metal substrate.

35. An article comprising a first substrate, a second substrate, and a cured composition disposed between and adhering the first substrate to the second substrate, wherein the cured composition is a reaction product of the curable composition of any one of claims 1 to 30.

36. A battery module comprising a plurality of battery cells connected to a first substrate by a first layer of a reaction product of the curable composition of any one of claims 1 to 30.

37. A method of manufacturing a battery module, the method comprising: applying a first layer of the curable composition of any one of claims 1 to 30 to a first surface of a first substrate, attaching a plurality of battery cells to the first layer to connect the battery cells to the first substrate, and curing the curable composition.

Technical Field

The present disclosure generally relates to curable compositions comprising an epoxy composition and a thiol composition. The curable composition may be used, for example, as a thermally conductive gap filler, which may be suitable for use in electronic applications, such as battery components.

Background

Curable compositions based on epoxy resins or polyamide resins have been disclosed in the art. Such curable compositions are described, for example, in U.S. patent 9,926,405, U.S. patent application publication 2013/0165600, and european patent 1291390.

Disclosure of Invention

In some embodiments, a curable composition is provided. The composition comprises: a first part comprising an epoxy resin; and a second part comprising a multifunctional thiol-containing compound. The curable composition further includes an inorganic filler present in an amount of at least 20 weight percent based on the total weight of the curable composition. The multifunctional thiol-containing compound comprises an ether in its backbone.

Drawings

Fig. 1 illustrates components of an exemplary battery module according to some embodiments of the present disclosure.

Fig. 2 shows an assembled battery module corresponding to fig. 1.

Fig. 3 illustrates components of an exemplary battery subunit, according to some embodiments of the present disclosure.

Detailed Description

Thermal management plays an important role in many electronic applications, such as Electric Vehicle (EV) battery packs, power electronics, electronic packaging, LEDs, solar cells, power grids, and the like. Certain thermally conductive materials (e.g., adhesives) may be an attractive option for these applications due to good electrical insulation properties, the feasibility of machining integrated components or complex geometries, and good conformability/wettability to different surfaces, particularly to effectively dissipate heat while having good adhesion to different substrates for assembly.

With respect to applications in EV battery components, currently, one such application that utilizes thermally conductive materials is gap filler applications. Generally, in addition to having a low viscosity prior to curing, requirements for gap filler applications include high thermal conductivity, good lap shear adhesion strength, good tensile strength, good ductile elongation at break, and damping properties, as well as good hydrolytic stability. However, in order to achieve high thermal conductivity, a large amount of inorganic thermally conductive filler is generally added to the composition. However, high loadings of thermally conductive fillers have a detrimental effect on adhesion properties, toughness, damping properties and viscosity.

In addition, compositions useful for gap filler applications should have relatively fast cure profiles to accommodate the automated processing requirements of the industry. For example, thermally conductive materials that achieve sufficient green strength after curing at room temperature for about 10 minutes or less can be particularly advantageous.

Filled curable compositions comprising epoxy resins, polyamide compositions, amino-functional compounds and multifunctional (meth) acrylates provide many of the above attributes, but do not provide sufficient hydrolytic stability in some applications. Another filled curable composition, which includes an epoxy composition and a polyamide composition comprising a polyamide having one or more tertiary amides in the main chain, also provides many of the above attributes, but in some applications does not provide sufficient green strength.

In order to solve the above-mentioned problems associated with high loadings of inorganic thermally conductive fillers, a curable composition (which includes an epoxy composition and a thiol composition) that provides a good balance of the above-mentioned desirable characteristics has been discovered. In particular, in addition to exhibiting all of the desirable attributes described above, the curable compositions of the present disclosure also exhibit good hydrolytic stability and green strength.

As used herein:

the term "room temperature" refers to a temperature of 22 ℃ to 25 ℃.

The terms "cure" and "curable" refer to the joining together of polymer chains by covalent chemical bonds, typically through cross-linking molecules or groups, to form a network polymer. Thus, in the present disclosure, the terms "cured" and "crosslinked" may be used interchangeably. Generally, the cured or crosslinked polymer is characterized as insoluble, but can be swellable in the presence of a suitable solvent.

The term "unfilled," when used in connection with a component or composition, refers to all materials (except for inorganic fillers (e.g., thermally conductive fillers)) that make up the component or composition.

The term "backbone" refers to the predominantly continuous chain of the polymer.

The term "aliphatic" refers to C1-C40, suitably C1-C30 straight or branched chain alkenyl, alkyl, or alkynyl groups that may or may not be interrupted or substituted with one or more heteroatoms, such as O, N or S.

The term "cycloaliphatic" refers to a cyclized aliphatic C3-C30, suitably C3-C20 group, and includes those interrupted by one or more heteroatoms (such as O, N or S).

The term "alkyl" refers to a monovalent group that is a radical of an alkane and includes straight-chain, branched, cyclic, and bicyclic alkyl groups and combinations thereof, including both unsubstituted and substituted alkyl groups. Unless otherwise indicated, alkyl groups typically contain 1 to 30 carbon atoms. In some embodiments, the alkyl group comprises 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. Examples of "alkyl" groups include, but are not limited to, methyl, ethyl, n-propyl, n-butyl, n-pentyl, isobutyl, tert-butyl, isopropyl, n-octyl, n-heptyl, ethylhexyl, cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, norbornyl, and the like.

The term "alkylene" refers to a divalent group that is a radical of an alkane and includes straight chain groups, branched chain groups, cyclic groups, bicyclic groups, or combinations thereof. Unless otherwise indicated, the alkylene group typically has 1 to 30 carbon atoms. In some embodiments, the alkylene group has 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. Examples of "alkylene" groups include methylene, ethylene, 1, 3-propylene, 1, 2-propylene, 1, 4-butylene, 1, 4-cyclohexylene, and 1, 4-cyclohexyldimethylene.

The term "aromatic" refers to C3-C40, suitably C3-C30, aromatic groups, including carbocyclic aromatic groups, as well as heterocyclic aromatic groups containing one or more of heteroatoms O, N or S and fused ring systems containing one or more of these aromatic groups fused together.

The term "aryl" refers to a monovalent group that is aromatic and optionally carbocyclic. The aryl group has at least one aromatic ring. Any additional rings may be unsaturated, partially saturated, or aromatic. Optionally, the aromatic ring can have one or more additional carbocyclic rings fused to the aromatic ring. Unless otherwise indicated, aryl groups typically contain from 6 to 30 carbon atoms. In some embodiments, the aryl group contains 6 to 20 carbon atoms, 6 to 18 carbon atoms, 6 to 16 carbon atoms, 6 to 12 carbon atoms, or 6 to 10 carbon atoms. Examples of aryl groups include phenyl, naphthyl, biphenyl, phenanthryl, and anthracyl.

The term "arylene" refers to a divalent group that is aromatic and optionally carbocyclic. The arylene group has at least one aromatic ring. Optionally, the aromatic ring can have one or more additional carbocyclic rings fused to the aromatic ring. Any additional rings may be unsaturated, partially saturated, or saturated. Unless otherwise specified, arylene groups often have 6 to 20 carbon atoms, 6 to 18 carbon atoms, 6 to 16 carbon atoms, 6 to 12 carbon atoms, or 6 to 10 carbon atoms.

The term "aralkyl" refers to a monovalent group that is an alkyl group substituted with an aryl group (e.g., as in a benzyl group). The term "alkaryl" refers to a monovalent group that is an aryl group substituted with an alkyl group (e.g., as in a tolyl group). Unless otherwise specified, for both groups, the alkyl moiety often has 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms, and the aryl moiety often has 6 to 20 carbon atoms, 6 to 18 carbon atoms, 6 to 16 carbon atoms, 6 to 12 carbon atoms, or 6 to 10 carbon atoms.

Repeat use of reference characters in the present specification is intended to represent same or analogous features or elements of the present disclosure. As used herein, the word "between … …" applied to a numerical range includes the endpoints of that range unless otherwise specified. The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range.

It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope and spirit of the principles of this disclosure. Unless defined otherwise, all scientific and technical terms used herein have the same meaning as commonly understood in the art. The definitions provided herein will facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure. As used in this specification and the appended claims, the singular forms "a", "an", and "the" encompass embodiments having plural referents, unless the context clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the context clearly dictates otherwise.

In some embodiments, the present disclosure provides a highly filled thermally conductive curable composition formulated by blending an epoxy composition and a thiol composition.

In some embodiments, the epoxy composition may comprise one or more epoxy resins. Suitable epoxy resins may include aromatic polyepoxide resins (e.g., chain-extended diepoxide or novolac epoxy resins having at least two epoxide groups), aromatic monomeric diepoxides, aliphatic polyepoxides, or monomeric diepoxides. The crosslinkable epoxy resin will generally have at least two epoxy end groups. The aromatic polyepoxides or aromatic monomeric diepoxides typically contain at least one (in some embodiments, at least 2, and in some embodiments, in a range from 1 to 4) aromatic ring, alkyl group having 1 to 4 carbon atoms (e.g., methyl or ethyl), or hydroxyalkyl group having 1 to 4 carbon atoms (e.g., hydroxymethyl) optionally substituted with a halogen (e.g., fluorine, chlorine, bromine, iodine). For epoxy resins containing two or more aromatic rings, the rings may be attached, for example, by a branched or straight chain alkylene group having 1 to 4 carbon atoms, which may optionally be substituted with halogen (e.g., fluoro, chloro, bromo, iodo).

In some embodiments, examples of aromatic epoxy resins useful in the epoxy compositions disclosed herein may include novolac epoxy resins (e.g., phenol novolac, o-cresol novolac, m-cresol novolac, or p-cresol novolac, or combinations thereof), bisphenol epoxy resins (e.g., bisphenol a, bisphenol F, halogenated bisphenol epoxies, and combinations thereof), resorcinol epoxy resins, tetraphenylphenol alkyl epoxy resins, and combinations of any of these.

In some embodiments, useful epoxy compounds include difunctional phenolic compounds (e.g.,p, p ' -dihydroxydibenzyl, p ' -dihydroxydiphenyl, p ' -dihydroxyphenylsulfone, p ' -dihydroxybenzophenone, 2 ' -dihydroxy-1, 1-dinaphthylmethane, and the 2,2 ', 2, 3', 2,4 ', 3', 3,4 ', and 4, 4' isomers of dihydroxydiphenylmethane, dihydroxydiphenyldimethylmethane, dihydroxydiphenylethylmethylmethane, dihydroxydiphenylmethylpropylmethane, dihydroxydiphenylethylphenylmethane, dihydroxydiphenylpropylphenylmethane, dihydroxydiphenylbutylphenylmethane, dihydroxydiphenyltolylethane, dihydroxydiphenyltolylmethylmethane, dihydroxydiphenyldicyclohexylmethane, and dihydroxydiphenylcyclohexane). In some embodiments, the adhesive comprises a bisphenol diglycidyl ether in which the bisphenol (i.e., -O-C)₆H₅—CH₂—C₆H₅-O-) may be unsubstituted (e.g., bisphenol F), or any of the phenyl ring or methylene groups may be substituted with one or more halogen (e.g., fluorine, chlorine, bromine, iodine), methyl groups, trifluoromethyl groups, or hydroxymethyl groups.

In some embodiments, examples of aromatic monomeric diepoxides useful in epoxy compositions according to the present disclosure include diglycidyl ethers of bisphenol a and bisphenol F, and mixtures thereof. For example, the bisphenol epoxy resin may be chain extended to have any desired epoxy equivalent weight. Chain extension of epoxy resins can be carried out by reacting monomeric diepoxides, for example, with bisphenols, in the presence of a catalyst to produce linear polymers. Other aromatic epoxy resins may include difunctional epoxy resins having a polysulfide polymer backbone, such as block copolymers of Thiokol LP and bisphenol F epoxy resins (e.g., FLEP-60 available from Toray Fine Chemicals co., ltd., Tokyo, Japan).

In some embodiments, the aromatic epoxy resin (e.g., a bisphenol epoxy resin or a novolac epoxy resin) may have an epoxy equivalent weight of at least 150, 170, 200, or 225 grams per equivalent. In some embodiments, the aromatic epoxy resin may have an epoxy equivalent weight of up to 2000, 1500, or 1000 grams per equivalent. In some embodiments, the aromatic epoxy resin may have an epoxy equivalent weight in a range from 150 to 2000, 150 to 1000, or 170 to 900 grams per equivalent. In some embodiments, the first epoxy resin has an epoxy equivalent weight in a range from 150 to 450, 150 to 350, or 150 to 300 grams per equivalent. For example, the epoxy equivalent weight may be selected so that the epoxy resin may be used as a liquid or solid as desired.

In some embodiments, the epoxy resins of the present disclosure may include one or more non-aromatic epoxy resins in addition to or as an alternative to aromatic epoxy resins. In some cases, the non-aromatic epoxy resin may serve as a reactive diluent that may help control the flow characteristics of the composition. The non-aromatic epoxy resins useful in the curable compositions according to the present disclosure may comprise a branched or straight chain alkylene group having 1 to 20 carbon atoms optionally interrupted by at least one-O-and optionally substituted with a hydroxyl group. In some embodiments, the non-aromatic epoxy group may include a compound having a plurality (x) of oxyalkylene groups OR¹Wherein each IV is independently C₂To C₅Alkylene, in some embodiments, is C₂To C₃Alkylene, x is 2 to about 6, 2 to 5, 2 to 4, or 2 to 3. For crosslinking into a network, useful non-aromatic epoxy resins will generally have at least two epoxy end groups. Examples of useful non-aromatic epoxy resins include glycidyl epoxy resins such as those based on diglycidyl ether compounds containing one or more oxyalkylene units. Examples of these substances include resins made of ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerol triglycidyl ether, propylene glycol diglycidyl ether, butylene glycol diglycidyl ether, and hexylene glycol diglycidyl ether. Other useful non-aromatic epoxy resins include diglycidyl ether of cyclohexanedimethanol, diglycidyl ether of neopentyl glycol, trimethylolpropaneTriglycidyl ether of an alkane and diglycidyl ether of 1, 4-butanediol. A crosslinked aromatic epoxy resin (i.e., an epoxy polymer) as described herein can be understood as being prepared by crosslinking an aromatic epoxy resin. The crosslinked aromatic epoxy group typically contains a repeating unit having at least one (in some embodiments, at least 2, and in some embodiments, in the range of from 1 to 4) aromatic ring (e.g., phenyl group) optionally substituted with one or more halogen (e.g., fluorine, chlorine, bromine, iodine), alkyl group having from 1 to 4 carbon atoms (e.g., methyl or ethyl), or hydroxyalkyl group having from 1 to 4 carbon atoms (e.g., hydroxymethyl). For repeat units containing two or more aromatic rings, the rings can be attached, for example, by a branched or straight chain alkylene group having 1 to 4 carbon atoms, which can optionally be substituted with halogen (e.g., fluoro, chloro, bromo, iodo).

In some embodiments, the epoxy resins of the present disclosure may be liquid at room temperature. Several curable epoxy resins useful in epoxy compositions according to the present disclosure are commercially available. For example, several epoxy resins of various classes and epoxy equivalents are available from the following suppliers: olin Corporation of Cletton, Mo (Olin Corporation, Clayton, Mo); hansen Inc. of Columbus, Ohio (Hexion Inc., Columbus, Ohio) Hunsmman Advanced Materials, The Woodlans, Tex., of Woodland, U.S.A.; CVC Specialty Chemicals inc, akron, Ohio, usa (purchased from Emerald Performance Materials); and southern Asia Plastics industries, Inc. of Taipei City, Taiwan (Nan Ya Plastics Corporation, Taipei City, Taiwan, China). Examples of commercially available glycidyl ethers include diglycidyl ethers of bisphenol a (e.g., those available under the trade names "EPON 828", "EPON 1001", "EPON 1310", and "EPON 1510" from vash corporation of columbic, ohio, "those available under the trade name" d.e.r.331, 332, and 334, "those available under the trade name" EPICLON "from forest corporation (Dainippon Ink and Chemicals, Inc.), such as EPICLON 840 and 850, and those available under the trade name" YL-980 "from Japan Epoxy Resins, Inc.); diglycidyl ether of bisphenol F (for example, those available under the trade name "EPICLON" from japan ink chemical industries co., ltd. (for example, "EPICLON 830")); polyglycidyl ethers of phenolic resins (e.g., novolac epoxy resins such as those available from forest company under the trade designation "d.e.n." (e.g., d.e.n.425, 431, and 438)); and flame retardant epoxy resins (e.g., "d.e.r.560", available from forest company as brominated bisphenol type epoxy resins). Examples of commercially available non-aromatic epoxy resins include the glycidyl ether of cyclohexanedimethanol, available from spain under the trade designation "HELOXY modifer 107".

In some embodiments, aromatic epoxy resins useful in the epoxy compositions disclosed herein may include flexible bisphenol a, bisphenol F, or bisphenol Z epoxy resins represented by the following structural formula:

wherein Ar is an aromatic group (which may include bisphenol a, bisphenol F, or bisphenol Z) having 10 to 20 carbon atoms and 0 to 5 substituents selected from aliphatic hydrocarbon groups, ether groups, or combinations thereof.

Examples of suitable aromatic epoxy resins include those available under the trade names ARALDITE PY-4122 from Hensman, woodland, Texas, from SHIN-A T & C under the trade name SE-4125P, and from Vast corporation, Columbus, Ohio under the trade name Epon 872.

In some embodiments, the epoxy composition of the present disclosure may comprise an amount of epoxy resin between 5 and 40 weight percent, 10 and 30 weight percent, 15 and 30 weight percent, or 20 and 30 weight percent (or possibly even higher (up to 95%, 99%, or 100%) for curable compositions that do not comprise a filler) based on the total weight of the epoxy composition. In some embodiments, the epoxy composition of the present disclosure may comprise an epoxy resin in an amount of at least 10 weight percent, at least 20 weight percent, at least 30 weight percent, at least 40 weight percent, or at least 50 weight percent, based on the total weight of the epoxy composition.

In some embodiments, the thiol composition may comprise one or more multifunctional functional thiol-containing compounds. As used herein, thiol refers to an organosulfur compound containing a carbon-bonded sulfhydryl (sulfhydryl) or mercapto (-C-SH) group. In some embodiments, the multifunctional functional thiol-containing compound can comprise at least two functional thiols. In some embodiments, one or more functional thiols of the multifunctional thiol-containing compound may be a terminal thiol. In some embodiments, the multifunctional thiol-containing compound may comprise an ether in its backbone. In some embodiments, in addition to the functional thiol, the multifunctional thiol-containing compound may comprise, for example, one or more alcohol or amine functional groups. In some embodiments, the multifunctional thiol may be a bifunctional thiol, a trifunctional thiol, a tetrafunctional thiol, or a multifunctional thiol.

In some embodiments, the multifunctional thiol-containing compound can include a compound represented by the following structural formula:

wherein R is an aliphatic hydrocarbon having 3 to 11 or 5 to 9 carbon atoms, n is 0 to 20 or 1 to 10, and m is 2 to 4 or 2 to 3.

In some embodiments, the multifunctional thiol-containing compound can include a compound represented by the following structural formula:

wherein each R1, R2, and R3 is independently an alkyl group having 1 to 4 or 1 to 3 carbon atoms or hydrogen, and n is 0 to 20 or 1 to 10.

Examples of suitable commercially available multifunctional thiol-containing compounds include those available under the trade names GPM-800LO, GPM-800, and Capcure 3-800 from Gabriel Chemical, Akron, OH, California, Akron, Ohio, and tetra (ethylene glycol) dithiol available under the trade name DMDO (1, 8-dimercapto-3, 6-dioxaoctane) from Sigma Aldrich, Saint Louis, Mo, St.

In some embodiments, the multifunctional thiol-containing compound may be used alone or as a mixture of two or more different thiol-functional compounds. In some embodiments, the multifunctional functional thiol-containing compound of the thiol composition can be a liquid (e.g., a viscous liquid having a viscosity of about 500-50,000 cP).

In some embodiments, the epoxy composition and the thiol composition may be present in the curable composition based on a stoichiometric ratio of the functional groups of the respective components. Using such relative amounts may be advantageous because the amount of residual unreacted thiol or epoxide in the cured composition may be reduced, which residual components may migrate or present environmental or health challenges.

In some embodiments, the curable composition of the present disclosure may be provided (e.g., packaged) as a two-part composition, wherein the first part comprises an epoxy composition (hereinafter "first part") and the second part comprises a thiol composition (hereinafter "second part"). In some embodiments, the first portion may comprise at least 50 wt%, at least 60 wt%, or at least 68 wt%, based on the total weight of the unfilled first portion; or an amount between 50 and 90, 60 and 80, or 65 and 70 weight percent epoxy resin. In some embodiments, the second part may comprise at least 50 wt%, at least 60 wt%, at least 70 wt%, or at least 76 wt%, based on the total weight of the unfilled second part; or between 50 wt.% and 90 wt.%, between 65 wt.% and 88 wt.%, or between 73 wt.% and 78 wt.% of the multifunctional thiol-containing compound. In some embodiments, the curable composition may comprise at least 20 wt%, at least 30 wt%, or at least 35 wt%, based on the total weight of the unfilled curable composition; or an amount between 20 and 60 weight percent, between 35 and 45 weight percent, or between 37 and 40 weight percent of an epoxy resin. In some embodiments, the curable composition may comprise at least 10 wt%, at least 20 wt%, or at least 30 wt%, based on the total weight of the unfilled curable composition; or a multifunctional thiol-containing compound in an amount between 20 wt% and 60 wt%, between 35 wt% and 45 wt%, or between 33 wt% and 35 wt%.

In addition to the above materials, the first and second parts may independently comprise one or more additives, such as inorganic fillers, coupling agents, toughening agents, dispersants, catalysts, antioxidants, and the like, which are described in further detail below. The present disclosure also provides a dispenser comprising a first chamber and a second chamber. The first chamber contains a first portion and the second chamber contains a second portion.

In some embodiments, the curable composition may include one or more inorganic fillers (e.g., thermally conductive inorganic fillers). The inorganic filler may be provided to the curable composition via the first part, the second part, both parts, or after mixing the first part and the second part. Generally, the selection and loading of the inorganic filler can be used to control the thermal conductivity of the curable composition. In some embodiments, the inorganic filler loading can be at least 20 volume percent, at least 30 volume percent, at least 40 volume percent, at least 50 volume percent, at least 60 volume percent, at least 70 volume percent, at least 80 volume percent, based on the total volume of any or all of the epoxy composition, the thiol composition, or the curable composition. In some embodiments, the inorganic filler loading may be between 20 and 90 vol%, between 30 and 80 vol%, between 50 and 70 vol%, or between 60 and 65 vol%, based on the total volume of any or all of the epoxy composition, the thiol composition, or the curable composition.

Generally, any known thermally conductive filler may be used, but electrically insulating fillers may be preferred where breakdown voltage is a concern. Suitable electrically insulating, thermally conductive fillers include ceramics such as oxides, hydroxides, oxyhydroxides, silicates, borides, carbides, and nitrides. Suitable ceramic fillers include, for example, silica, alumina, aluminum hydroxide (ATH), boron nitride, silicon carbide, and beryllium oxide. In some embodiments, the thermally conductive filler comprises ATH. It will be appreciated that while ATH is not typically used in polyurethane-based compositions typically employed in thermal management materials due to its reactivity with isocyanate species and the resulting formulation difficulties, the curable compositions of the present disclosure can incorporate such inorganic fillers without drawbacks. Other thermally conductive fillers include carbon-based materials (such as graphite) and metals (such as aluminum and copper).

Thermally conductive filler particles are available in a variety of shapes, such as spheres, irregular shapes, plates, and needles. In some applications, through-plane thermal conductivity may be important. Thus, in some embodiments, a generally symmetrical (e.g., spherical or hemispherical) filler may be employed. To facilitate dispersion and increase filler loading, in some embodiments, the thermally conductive filler may be surface treated or coated. Generally, any known surface treatment and coating may be suitable, including those based on silane, titanate, zirconate, aluminate, and organic acid chemistries. Many fillers may be used as polycrystalline agglomerates or aggregates, with or without a binder, for powder handling purposes. To facilitate high thermal conductivity formulations, some embodiments may include mixtures of particles and agglomerates of various sizes, as well as mixtures.

In some embodiments, the curable compositions of the present disclosure may comprise one or more silane coupling agents. Silane coupling agents have been found to meaningfully improve the lap shear strength of the cured curable composition after aging. In some embodiments, the silane coupling agent may be provided to the curable composition via the first part, the second part, both parts, or after mixing the first part and the second part. Suitable silane coupling agents may include silane thiols, silane amines (e.g., silane secondary amines), or silane epoxides.

In some embodiments, suitable Silane Coupling Agents may include those described in e.p. plueddemann, Silane Coupling Agents, 2 nd edition, Springer US, New York,1991, which is incorporated by reference herein in its entirety. In some embodiments, suitable silane coupling agents may be described as organosilicon compounds having two functional groups that differ in reactivity (one of the two functional groups reacting with an inorganic material and the other typically reacting with an organic material). In some embodiments, the silane coupling agent may have the following general structural formula:

wherein Y is a functional group compatible with or attached to an organic material, such as a vinyl group, an epoxy group, an amino group, a thiol group, an isocyanate group, or the like; r is an aliphatic group (typically an aliphatic group having 2 to 6 carbon atoms); and X is a functional group (e.g., a chlorine, alkoxy, or acetoxy group) that is hydrolyzed by water or moisture to form silanol, and n is 1-3 or 1-2.

Examples of suitable silane coupling agents include 3-glycidoxypropyltriethoxysilane, 5, 6-epoxyhexyltriethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltriethoxysilane, gamma-mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, s- (octanoyl) mercaptopropyltriethoxysilane, hydroxy (polyethyleneoxy) propyltriethoxysilane, N- (N-butyl) -3-aminopropyltrimethoxysilane, or combinations thereof.

In some embodiments, the first part may comprise a silane epoxy resin and the second part may comprise either or both of a silane thiol and a silane amine.

In some embodiments, the silane coupling agent may be at least 0.1 wt%, at least 10 wt%, or at least 15 wt%, based on the total weight of the unfilled curable composition; or between 0.1 and 60 weight percent, between 9 and 20 weight percent, or between 14 and 17 weight percent. In some embodiments, the silane coupling agent may be at least 0.1 weight percent, at least 15 weight percent, or at least 20 weight percent based on the total weight of the unfilled first portion; or between 50 wt% and 90 wt%, between 60 wt% and 80 wt%, or between 65 wt% and 70 wt% is present in the first portion. In some embodiments, the silane coupling agent may be at least 0.1 wt%, at least 5 wt%, or at least 10 wt%, based on the total weight of the unfilled second portion; or between 0.1 wt% and 40 wt%, between 5 wt% and 16 wt%, or between 9 wt% and 11 wt% is present in the second portion.

In some embodiments, curable compositions according to the present disclosure may comprise one or more catalysts. Generally, the catalyst may function to accelerate curing of the curable composition. Suitable catalysts according to the present disclosure may include basic catalysts, lewis acid catalysts, or combinations thereof.

In some embodiments, suitable basic catalysts may include nitrogen-containing catalysts. In some embodiments, the nitrogen-containing catalyst may comprise an amine-containing catalyst. In some embodiments, the amine-containing catalyst can comprise the formula-NR¹R²At least two radicals of (a), wherein R¹And R²Independently selected from hydrogen, alkyl, aryl, alkaryl or aralkyl. Suitable alkyl groups often have 1 to 12 carbon atoms, 1 to 8 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. The alkyl group may be cyclic, branched, straight chainOr a combination thereof. Suitable aryl groups typically have 6 to 12 carbon atoms, such as phenyl or biphenyl groups. Suitable alkylaryl groups can include the same aryl and alkyl groups discussed above. In some embodiments, the amine-containing catalyst can be an imidazole, an imidazolium salt, and an imidazoline, or a combination thereof. Aromatic tertiary amines may also be used as catalysts, including those having the following structural formula:

wherein R is⁴Is hydrogen or an alkyl group; r⁵、R⁶And R⁷Independently hydrogen or CHNR⁸R⁹Wherein at least one of R5, R6, and R7 is CHNR⁸R⁹And R is⁸And R⁹Independently an alkyl group. In some embodiments, R⁴、R⁸And/or R⁹The alkyl group of (a) is a methyl or ethyl group. In some embodiments, the amine-containing catalyst may comprise tris-2, 4,6- (dimethylaminomethyl) phenol, which is commercially available from Evonik Corporation, Parsippany, N.J., under the trade name ANCAMINE K54 and has the structural formula:

in some embodiments, the nitrogen-containing catalyst may comprise cyclic or bridged nitrogen-containing compounds, including amidine compounds such as 1, 5-diaza-bicyclo [4.3.0] non-5-ene (DBN) and 1, 8-diaza-bicyclo [5.4.0] undec-7-ene (DBU), and diazabicyclo [2.2.2] octane (DABCO) of Sigma Aldrich, Saint Louis, MO, US, having the following structural formula:

in some embodiments, the catalyst may be present in the curable composition (or either or both of the first part or the second part) in an amount between 100ppm and 10,000ppm, or between 200ppm and 5,000ppm, based on the total weight or total volume of any or all of the unfilled curable composition, the unfilled first part, or the unfilled second part. It has been found that the use of a cyclic nitrogen-containing catalyst (such as DABCO) can significantly reduce the cure time (e.g., by up to 6-fold) of the curable compositions of the present disclosure relative to the cure time using a non-cyclic nitrogen-containing catalyst (such as K54).

In some embodiments, the basic catalyst may be at least 1 wt%, at least 2 wt%, or at least 3 wt%, based on the total weight of the unfilled curable composition; or between 1 and 20 weight percent, between 2 and 10 weight percent, or between 3 and 5 weight percent. In some embodiments, the second portion may comprise a basic catalyst. In some embodiments, the basic catalyst may be at least 0.5 wt%, at least 5 wt%, or at least 7 wt%, based on the total weight of the unfilled second portion; or between 0.5 wt% and 30 wt%, between 5 wt% and 15 wt%, or between 7 wt% and 10 wt% is present in the second portion. In some embodiments, the second part may comprise a lewis acid catalyst. In some embodiments, the lewis acid catalyst may be at least 1 wt%, at least 2 wt%, or at least 3 wt%, based on the total weight of the unfilled curable composition; or between 1 and 20 weight percent, between 2 and 10 weight percent, or between 3 and 5 weight percent. In some embodiments, the lewis acid catalyst may be at least 0.5 wt%, at least 5 wt%, or at least 7 wt%, based on the total weight of the unfilled second part; or between 0.5 wt% and 30 wt%, between 5 wt% and 15 wt%, or between 7 wt% and 10 wt% is present in the second portion.

In some embodiments, curable compositions according to the present disclosure may include one or more dispersants. Generally, the dispersant may act to stabilize the inorganic filler particles in the composition, and in the absence of the dispersant, these particles may aggregate, thereby adversely affecting the benefits of the particles in the composition. Suitable dispersants may depend on the specific characteristics and surface chemistry of the filler. In some embodiments, suitable dispersants according to the present disclosure may comprise at least a binding group and a compatible segment. The binding group may be ionically bonded to the particle surface. Examples of binding groups for the alumina particles include phosphoric acid, phosphonic acid, sulfonic acid, carboxylic acid, and amine. The compatible segment may be selected to be miscible with the curable matrix. For epoxy resin matrices, useful compatibilizing agents may include polyalkylene oxides (e.g., polypropylene oxide, polyethylene oxide), and polycaprolactone, as well as combinations thereof. Commercially available examples include BYK W-9010 (BYK Additives and Instruments), BYK W-9012 (BYK Chemicals and Instruments), Disberbyk 180 (BiKYK Chemicals and Instruments) and Solplus D510 (Lubrizol Corporation). In some embodiments, the dispersant may be present in the curable composition in an amount between 0.1 and 10 wt.%, between 0.1 and 5 wt.%, between 0.5 and 3 wt.%, or between 0.5 and 2 wt.%, based on the total weight of the unfilled curable composition. In some embodiments, the dispersant may be present in the unfilled curable composition (or first part or second part) in an amount between 0.1 wt% and 30 wt%, between 1 wt% and 20 wt%, between 5 wt% and 15 wt%, or between 7 wt% and 10 wt%, based on the total weight of the unfilled first part, the unfilled second part, or the total weight of the unfilled curable composition.

In some embodiments, the dispersant may be pre-mixed with the inorganic filler prior to incorporation into any or all of the first part, second part, or curable composition. Such premixing may facilitate the filled system to behave like a newtonian fluid or be capable of achieving shear thinning effect behavior.

In addition to the additives discussed above, additional additives may be included in one or both of the first and second parts. For example, any or all of antioxidants/stabilizers, colorants, abrasive particles, thermal degradation stabilizers, light stabilizers, conductive particles, core shell tougheners, adhesion promoters, leveling agents, base agents, matting agents, inert fillers, binders, blowing agents, fungicides, bactericides, surfactants, plasticizers, flame retardants, and other additives known to those skilled in the art. If present, these additives are added in amounts effective for their intended use.

In some embodiments, after curing, the curable compositions of the present disclosure may exhibit thermal, mechanical, and rheological properties that make the compositions particularly useful as thermally conductive gap fillers. For example, it is believed that for certain EV battery component applications, the curable compositions of the present disclosure provide an optimal blend of tensile strength, elongation at break, and lap shear strength (even after aging).

In some embodiments, the cured composition may have the following elongation at break: for a fully cured system, in the range of 0.1% to 100%, 0.5% to 80%, 1% to 50%, or 8% to 15% at a Tensile rate of between 0.8mm/min and 1.5mm/min (for the purposes of this application, elongation at break values are measured according to ASTM D638-14 "Standard Test Method for Tensile Properties of Plastics)"; or at least 1%, at least 3%, at least 7%, at least 10%, at least 15% at a draw rate of between 0.8mm/min and 1.5mm/min for a fully cured system.

In some embodiments, the cured composition may have the following lap shear strength on bare aluminum substrates: for a fully cured system, at 1N/mm²-30N/mm²、1N/mm²-25N/mm²、4N/mm²-20N/mm²、6N/mm²-20N/mm²、2N/mm²-16N/mm²Or 3N/mm²-8N/mm²(for purposes of this application, Lap Shear Strength values are measured on untreated aluminum substrates (i.e., aluminum substrates without a surface treatment or coating other than a native oxide layer) according to ASTM D1002-01 "Standard Test Method for applying Shear Strength of Single-Lap-Joint additive bonding Metal Specification by tensile load (Standard Test Method for testing the Apparent Shear Strength of a Single Lap Joint Bonded Metal specimen by tensile load)).

In some embodiments, the cured composition may have the following tensile strength: for a fully cured system, at a draw rate between 0.8mm/min and 1.5mm/min, at 0.5N/mm²-16N/mm²、1N/mm²-10N/mm²Or 2N/mm²-8N/mm²(Tensile strength values are measured according to ASTM D638-14 "Standard Test Method for Tensile Properties of Plastics" for the purposes of this application).

In some embodiments, the cured composition may be hydrolytically stable. In this regard, the cured composition may exhibit a lap shear strength retention (measured as described above) of more than 70% after humidity testing according to PR308.2 test method. Additionally or alternatively, the cured composition may exhibit a decrease in tensile strength (measured as described above) of less than 30% after humidity testing according to PR308.2 test method.

In some embodiments, the composition may have a desired cure rate. In this regard, the curable compositions of the present disclosure can exhibit a gel time (G' (storage modulus) equal to G "(loss modulus) at room temperature of no more than 10 minutes, 30 minutes, 60 minutes, or 80 minutes, as measured on a Discovery HR-3 rheometer equipped with a forced convection oven attachment (TA Instruments, Wood Dale, IL, US) at an angular frequency of 100rad/s, oscillatory shear rheometer measurement at 1% strain).

In some embodiments, after curing, the curable composition of the present disclosure may have a Thermal conductivity in the range of 1.0W/(m × K) to 5W/(m × K), 1.0W/(m × K) to 2W/(m × K), or 1.5W/(m × K) to 1.8W/(m × K) (for purposes of this application, the Thermal conductivity value is determined by first measuring the Diffusivity according to ASTM E1461-13 "Standard Test Method for Thermal Diffusivity by the Flash Method", then calculating the Thermal conductivity from the measured Thermal Diffusivity, Thermal capacity, and density measurements according to the following formula:

k＝α·cp·ρ，

where k is the thermal conductivity in W/(m K) and α is mm²Thermal diffusivity in units of/s, cp is the specific heat capacity in units of J/K-g, and ρ is g/cm³Is the density in units. The sample thermal diffusivity can be measured directly and relative to a standard, respectively, using Netzsch LFA 467 "HYPERFLASH" according to ASTM E1461-13. Sample density can be measured using geometric methods, while specific heat capacity can be measured using differential scanning calorimetry.

In some embodiments, the viscosity of the curable/partially cured composition may range from 100 poise to 50000 poise measured at room temperature and from 100 poise to 50000 poise measured at 60 ℃ within 10 minutes after mixing the first part and the second part. Further to the viscosity, the viscosity of the epoxy composition (prior to mixing) measured at room temperature may be in the range of 100 poise to 100000 poise, and the viscosity measured at 60 ℃ may be in the range of 10 poise to 10000 poise; and the viscosity of the thiol composition (prior to mixing) measured at room temperature may be in the range of 100 poise to 100000 poise, and the viscosity measured at 60 ℃ may be in the range of 10 poise to 10000 poise (for purposes of this application, the viscosity values are measured on an ARES rheometer equipped with a forced convection oven accessory (TA Instruments, New Castle, DE, USA), using a 25mm parallel plate geometry at 1% strain and an angular frequency of 10-500 rad/s).

The present disclosure also relates to a process for preparing the above curable composition. In some embodiments, the curable compositions of the present disclosure may be prepared by first mixing the components of the first part (including any additives) and then separately mixing the components of the second part (including any additives). The components of both the first and second parts may be mixed using any conventional mixing technique, including by using a flash mixer. In embodiments in which a dispersant is employed, the dispersant may be pre-mixed with the inorganic filler prior to incorporation into the composition. Next, the first part and the second part may be mixed together to form the curable composition using any conventional mixing technique.

In some embodiments, the curable compositions of the present disclosure may be capable of curing without the use of a catalyst or other curing agent. Generally, the curable composition can be cured under typical application conditions, such as at room temperature, without the need for elevated temperatures or actinic radiation (e.g., ultraviolet light). In some embodiments, the first curable composition is cured at a temperature no greater than room temperature.

In some embodiments, the curable composition of the present disclosure may be provided as a two-part composition. Generally, the two components of the two-part composition may be mixed prior to application to the substrate to be bonded. After mixing, the two-part composition can achieve the desired handling strength and ultimately achieve the desired final strength. Applying the curable composition can be performed, for example, by dispensing the curable composition from a dispenser comprising a first chamber, a second chamber, and a mixing tip, wherein the first chamber comprises the first portion, wherein the second chamber comprises the second portion, and wherein the first chamber and the second chamber are coupled to the mixing tip to allow the first portion and the second portion to flow through the mixing tip.

The curable compositions of the present disclosure may be used in coatings, shaped articles, adhesives (including structural and semi-structural adhesives), magnetic media, filled or reinforced composites, caulking and sealing compounds, casting and molding compounds, potting and encapsulation compounds, impregnating and coating compounds, conductive adhesives for electronic devices, protective coatings for electronic devices, as primers or adhesion promoting layers, and other applications known to those skilled in the art. In some embodiments, the present disclosure provides an article comprising a substrate having a cured coating of the curable composition thereon.

In some embodiments, the curable composition may be used as a structural adhesive, i.e., the curable composition is capable of bonding a first substrate to a second substrate after curing. Generally, the bond strength (e.g., peel strength, lap shear strength, or impact strength) of a structural adhesive is continuously developed after the initial cure time. In some embodiments, the present disclosure provides an article comprising a first substrate, a second substrate, and a cured composition disposed between and adhering the first substrate to the second substrate, wherein the cured composition is a reaction product of a curable composition of any of the curable compositions according to the present disclosure. In some embodiments, the first substrate and/or the second substrate may be at least one of a metal, a ceramic, and a polymer (e.g., a thermoplastic).

The curable composition may be coated onto the substrate at a useful thickness in a range of 5 micrometers to 10000 micrometers, 25 micrometers to 10000 micrometers, 100 micrometers to 5000 micrometers, or 250 micrometers to 1000 micrometers. Useful substrates may be of any nature and composition, and may be inorganic or organic. Representative examples of useful substrates include ceramics, siliceous substrates including glass, metals (e.g., aluminum or steel), natural and man-made stone, woven and non-woven articles, polymeric materials including thermoplastic and thermoset polymeric materials (such as polymethyl (meth) acrylate, polycarbonate, polystyrene, styrene copolymers such as styrene acrylonitrile copolymers, polyesters, polyethylene terephthalate), silicones, paints (such as those based on acrylics), powder coatings (such as polyurethane or mixed powder coatings), and wood; and composites of the foregoing materials.

In another aspect, the present disclosure provides a coated article comprising a metal substrate having a coating of an uncured, partially cured, or fully cured curable composition on at least one surface of the metal substrate. If the substrate has two major surfaces, the coating may be coated on one or both major surfaces of the metal substrate and may include additional layers such as tie layers, bonding layers, protective layers, and topcoat layers. The metal substrate can be, for example, at least one of an inner surface and an outer surface of a tube, container, conduit, rod, profile, sheet, or pipe.

In some embodiments, the present disclosure also relates to a battery module comprising the curable uncured, partially cured, or fully cured composition of the present disclosure. The components of a representative battery module during assembly are shown in fig. 1, and the assembled battery module is shown in fig. 2. The battery module 50 may be formed by positioning a plurality of battery cells 10 on the first substrate 20. Generally, any known battery cell may be used, including, for example, a hard-shell prismatic cell or a pouch cell. The number, size, and location of the cells associated with a particular battery module may be adjusted to meet specific design and performance requirements. The construction and design of the substrate is well known and any substrate suitable for the intended application (typically a metal substrate made of aluminum or steel) may be used.

The battery cell 10 may be connected to the first substrate 20 through the first layer 30 of the first curable composition according to any one of the embodiments of the present disclosure. The first layer 30 of the curable composition may provide a level of thermal management where the cells are assembled in a battery module. Since there may be a voltage difference between the battery cell and the first substrate (e.g. a voltage difference of up to 2.3 volts), the breakdown voltage may be an important safety feature of this layer. Thus, in some embodiments, electrically insulating fillers similar to ceramics (typically alumina and boron nitride) may preferably be used in the curable composition.

In some embodiments, the layer 30 may comprise a discontinuous pattern of the first curable composition applied to the first surface 22 of the first substrate 20, as shown in fig. 1. For example, a pattern of material of a desired layout of battery cells may be applied (e.g., robotically applied) to a surface of a substrate. In some embodiments, the first layer may be formed as a coating of the first curable composition covering all or substantially all of the first surface of the first substrate. In an alternative embodiment, the first layer may be formed by applying the curable composition directly to the battery cells and then mounting them to the first surface of the first substrate.

In some embodiments, the curable composition may need to accommodate dimensional changes of up to 2mm, up to 4mm, or even greater. Thus, in some embodiments, the first layer of the first curable composition may be at least 0.05mm thick, such as at least 0.1mm, or even at least 0.5mm thick. Depending on the electrical properties of the material, a higher breakdown voltage may require a thicker layer, for example, in some embodiments, a layer that is at least 1mm, at least 2mm, or even at least 3mm thick. Generally, to maximize heat conduction through the curable composition and minimize cost, the curable composition layer should be as thin as possible while still ensuring good contact with the heat spreader. Thus, in some embodiments, the thickness of the first layer is no greater than 5mm, such as no greater than 4mm or even no greater than 2 mm.

As the first curable composition cures, the cells are held more firmly in place. When curing is complete, the cells are finally secured in their intended positions, as shown in fig. 2. Additional elements (e.g., straps 40) may be used to secure the units for transport and further processing.

Generally, it is desirable that the curable composition be cured under typical application conditions, e.g., without the need for elevated temperatures or actinic radiation (e.g., ultraviolet light). In some embodiments, the first curable composition is cured at room temperature, or at a temperature no greater than 30 ℃ (e.g., no greater than 25 ℃, or even no greater than 20 ℃).

In some embodiments, the cure time is not longer than 60 minutes, such as not longer than 40 minutes or even not longer than 20 minutes. While very rapid curing (e.g., less than 5 minutes or even less than 1 minute) may be suitable for some applications, in some embodiments, an open time of at least 5 minutes (e.g., at least 10 minutes or even at least 15 minutes) may be required, thereby allowing time for cell positioning and repositioning. In general, it is desirable to achieve the desired cure time without the use of expensive catalysts such as platinum.

As shown in fig. 3, a plurality of battery modules 50 (such as those illustrated and described with respect to fig. 1 and 2) are assembled to form a battery sub-unit 100. The number, size, and location of modules associated with a particular battery sub-unit may be adjusted to meet specific design and performance requirements. The construction and design of the second substrate is known and any substrate (typically a metal substrate) suitable for the intended application may be used.

Each battery module 50 may be positioned on and connected to the second substrate 120 through the second layer 130 of the curable composition according to any one of the embodiments of the present disclosure.

A second layer 130 of a second curable composition may be positioned between the second surface 24 (see fig. 1 and 2) of the first substrate 20 and the first surface 122 of the second substrate 120. The second curable composition may provide a second level of thermal management, in which case the battery module is assembled into a battery subunit. At this level, breakdown voltage may not be a requirement. Thus, in some embodiments, electrically conductive fillers, such as graphite and metal fillers, may be used alone or in combination with electrically insulating fillers like ceramics.

In some embodiments, the second layer 130 may be formed as a coating of the second curable composition covering all or substantially all of the first surface 122 of the second substrate 120, as shown in fig. 3. In some embodiments, the second layer may comprise a discontinuous pattern of the second curable composition applied to a surface of the second substrate. For example, a material pattern corresponding to a desired layout of the battery modules may be applied (e.g., robotically applied) to a surface of the second substrate. In an alternative embodiment, the second layer may be formed by applying the second curable composition directly to the second surface 24 (see fig. 1 and 2) of the first substrate 20, and then mounting the module to the first surface 122 of the second substrate 120.

The assembled battery sub-units may be combined to form additional structures. For example, as is known, battery modules may be combined with other elements (e.g., battery control units) to form battery systems, such as those used in electric vehicles. In some embodiments, additional layers of curable compositions according to the present disclosure may be used to assemble such battery systems. For example, in some embodiments, a thermally conductive gap filler according to the present disclosure may be used to mount and help cool a battery control unit.

Detailed description of the embodiments

1. A curable composition comprising:

a first part comprising an epoxy resin; and

a second part comprising a multifunctional thiol-containing compound; and

an inorganic filler present in an amount of at least 20 weight percent based on the total weight of the curable composition,

wherein the multifunctional thiol-containing compound comprises an ether in its backbone.

2. The curable composition of embodiment 1, wherein one or more of the functional thiols is a terminal thiol.

3. The curable composition of embodiment 1, wherein the multifunctional thiol-containing compound is represented by the formula:

wherein R is an aliphatic hydrocarbon, n is 0 to 20, and m is 2 to 4.

4. The curable composition of embodiment 1, wherein the multifunctional thiol-containing compound is represented by one of the following formulas:

wherein each of R1, R2, and R3 is independently an alkyl group having 1 to 4 carbon atoms or hydrogen, and n is 0 to 20.

5. The curable composition of any one of the previous embodiments, wherein the epoxy resin comprises an internally flexible bisphenol epoxy resin.

6. The curable composition of embodiment 5, wherein the internally flexible bisphenol epoxy resin is represented by the formula:

wherein Ar is bisphenol A, bisphenol F, bisphenol Z, or a mixture thereof.

7. The curable composition according to any one of the preceding embodiments, wherein the epoxy resin comprises phosphonic acid groups in its backbone.

8. The curable composition of any one of the preceding embodiments, further comprising a silane coupling agent.

9. The curable composition of embodiment 8, wherein the silane coupling agent comprises an amine-terminated silane coupling agent.

10. The curable composition of embodiment 8, wherein the silane coupling agent comprises a thiol-terminated silane coupling agent.

11. The curable composition of embodiment 8, wherein the silane coupling agent comprises an epoxy-terminated silane coupling agent.

12. The curable composition of any one of the preceding embodiments, further comprising a catalyst.

13. The curable composition of embodiment 12, wherein the catalyst comprises a basic catalyst.

14. The curable composition of embodiment 13, wherein the basic catalyst is represented by one of the following formulas:

15. the curable composition of embodiment 12, wherein the catalyst comprises a lewis acid catalyst.

16. The curable composition of embodiment 15, wherein the lewis acid catalyst comprises calcium triflate, calcium nitrate, or a tin catalyst.

17. The curable composition of any one of the preceding embodiments, wherein epoxy resin is present in the curable composition in an amount of at least 20 weight percent based on the total weight of the unfilled curable composition.

18. The curable composition of any one of the preceding embodiments, wherein the multifunctional thiol-containing compound is present in the curable composition in an amount of at least 10 weight percent based on the total weight of the unfilled curable composition.

19. The curable composition of any one of the preceding embodiments, wherein the curable composition, after curing, has (i) an elongation at break of greater than 5.5%, and (ii) 5N/mm on untreated aluminum²-20N/mm²Lap shear strength of (a).

20. The curable composition of any one of the preceding embodiments, wherein the curable composition, after curing, has a tensile strength of from 1N/mm2 to 16N/mm 2.

21. The curable composition of any one of the preceding embodiments, wherein the curable composition retains at least 70% of lap shear strength after curing after humidity testing according to PR308.2 test method.

22. The curable composition of any one of the preceding embodiments, wherein the curable composition exhibits less than a 30% decrease in tensile strength after curing after humidity testing according to PR308.2 test method.

23. The curable composition according to any one of the preceding embodiments, wherein the curable composition exhibits a gel time at room temperature of no more than 60 minutes as determined on a Discovery HR-3 rheometer equipped with a forced convection oven attachment (TA Instruments, Wood Dale, IL, US) with an oscillating shear rheometer measurement at 100rad/s angular frequency at 1% strain.

24. The curable composition according to any one of the preceding embodiments, wherein the curable composition has a thermal conductivity of at least 1.0W/(m × K) after curing.

25. The curable composition of any one of the preceding embodiments, wherein the inorganic filler is present in an amount of at least 20 weight percent based on the total weight of the curable composition.

26. The curable composition of any one of the preceding embodiments, wherein the inorganic filler is present in an amount of at least 50 weight percent based on the total weight of the curable composition.

27. The curable composition of any one of the previous embodiments, wherein the inorganic filler comprises alumina.

28. The curable composition of any one of the preceding embodiments, wherein the inorganic filler comprises spherical alumina particles and hemispherical alumina particles.

29. The curable composition of any one of the previous embodiments, wherein the inorganic filler comprises silane surface treated particles.

30. The curable composition of any one of the preceding embodiments, wherein the inorganic filler comprises ATH.

31. An article comprising a cured composition, wherein the cured composition is a reaction product of the curable composition of any one of the preceding embodiments.

32. The article of embodiment 31, wherein the cured composition has a thickness of between 5 micrometers to 10000 micrometers.

33. The article of any one of embodiments 31 to 32, further comprising a substrate having a surface, wherein the cured composition is disposed on the surface of the substrate.

34. The article of embodiment 33, wherein the substrate is a metal substrate.

35. An article comprising a first substrate, a second substrate, and a cured composition disposed between and adhering the first substrate to the second substrate, wherein the cured composition is a reaction product of the curable composition of any one of embodiments 1-30.

36. A battery module comprising a plurality of battery cells connected to a first substrate by a first layer of a reaction product of the curable composition of any one of embodiments 1-30.

37. A method of manufacturing a battery module, the method comprising: applying a first layer of the curable composition according to any one of embodiments 1 to 30 to a first surface of a first substrate, attaching a plurality of battery cells to the first layer to connect the battery cells to the first substrate, and curing the curable composition.

Examples

Objects and advantages of the present disclosure are further illustrated by the following comparative and exemplary examples. Unless otherwise indicated, all parts, percentages, ratios, and the like in the examples and the remainder of the specification are by weight and all reagents used in the examples were obtained or purchased from general chemical suppliers, such as Sigma Aldrich corp.

Sample preparation

Table 1 summarizes the materials used in the examples.

TABLE 1 materials List

The detailed formulations of comparative example CE1 and examples 1 to 13 are listed in tables 2 and 3.

To prepare the samples, part a and part B were mixed separately as follows. First, the organic components were combined and mixed by hand. Thixotropic additives are then added followed by manual mixing. A high speed mixer (speednixer DAC 400, FlackTek company of randlam, south carolina, usa) was then used at 1500rpm for 2 minutes to thoroughly mix the materials. The remaining fill materials were combined and added to the formulation in 2 portions. After each portion was added, mix for 2 minutes at 2000RPM in a DAC 400 mixer. In the final step, the materials were mixed in the DAC 400 mixer at 1500RPM for 15 seconds at atmospheric pressure, then 30 torr and 2000RPM for two minutes, then again at 1500RPM for the final 15 seconds when the pressure was returned to atmospheric pressure.

Part a and part B are mixed based on a stoichiometric ratio of the functional groups, the moles of thiol groups in part a and the combined moles of epoxy groups in part B. Part a and part B were mixed using a pneumatic dispensing system with a static mixing nozzle at the ratios listed in tables 2 and 3.

TABLE 2 compositions of the examples

	CE-1	Ex.1	Ex.2	Ex.3	Ex.4
						Part A	By weight%	By weight%	By weight%	By weight%	By weight%
THIOCURE TMPMP	19.3	---	---	---	---
						GABEPRO GPM-800LO	---	16.5	25.7	21.3	21.3
DBU	1.9	---	---	---	---
						K54	---	1.7	2.6	2.1	2.1
MOLDX A110	77.2	---	---	---	---
						BAK-70	---	---	---	---	---
BAK-40	---	24.1	20.9	21.4	21.4
						MARTOXID TM-1250	---	56.2	48.8	50.0	---
MARTOXID TM-2250	---	---	---	---	50.0
						SOLPLUS D510	1.5	1.6	1.4	1.4	1.4
DISPERBYK 145	---	---	---	---	---
						CAB-O-SIL TS-720	---	---	0.70	0.71	0.71
						Part B	By weight%	By weight%	By weight%	By weight%	By weight%
ARALDITE PY-4122	15.3	5.1	4.5	3.9	3.9
						EPON 828	3.8	7.7	6.7	5.8	5.8
EP-49-10N	---	---	---	---	---
						XIAMETER OFS-6040	0.6	0.4	0.3	2.9	2.9
MOLDX A110	78.7	---	---	---	---
						BAK-70	---	---	---	---	---
BAK-40	---	25.4	25.8	25.4	25.4
						MARTOXID TM-1250	---	59.3	60.2	59.4	---
MARTOXID TM-2250	---	---	---	---	59.4
						SOLPLUS D510	1.6	1.7	1.7	1.7	1.7
DISPERBYK 145	---	---	---	---	---
						CAB-O-SIL TS-720	---	0.42	0.86	0.85	0.85
AEROSIL R202	---	---	---	---	---
Part A: part B (volume: volume)	1:2.28	1:1	1:2	1:2	1:2
Total Filler (% by weight)	78.30	82.06	82.10	81.6	81.6

TABLE 3 compositions of the examples

Testing workerSequence of steps

Overlap shear adhesion (OLS)

Two 1 inch (2.54 centimeters (cm)) wide by 4 inches (10cm) long by 0.125 inch (0.32cm) thick aluminum coupons were cleaned using Methyl Ethyl Ketone (MEK) and otherwise remained untreated. A 1 inch x 0.5 inch (2.54cm x 1.27cm) rectangle was covered with the mixed thiol/epoxy paste on top of one coupon and then laminated to another coupon in the opposite top direction to yield about 10 to 30 mils (0.25 to 0.76 millimeters (mm)) of paste between the aluminum coupons, which was clamped by a long tail clamp. The laminated aluminum coupons were then cured at room temperature for more than two days to provide complete cure prior to lap shear testing.

OLS tests were conducted on an INSTRON Universal tester model 1122 (INSTRON Corporation, Norwood, MA, USA) according to the procedure of ASTM D1002-01 "Standard Test Method for applying Shear Strength of Single-Lanp-Joint additive Bonded Metal Specification by Tension testing load (Metal-to-Metal)". The chuck speed was 0.05 inch/min (1.27 mm/min).

Tensile Properties

For Tensile strength testing, the mixed paste was pressed into a dog bone shaped silicone rubber mold and then laminated on both sides with a release liner, thereby preparing dog bone shaped samples according to ASTM D1708-13 "Standard Test Method for Tensile Properties of Plastics by Use of Microtensile Specifications". The dog bone shape resulted in a sample having a length of about 0.6 inches (1.5cm) in the central straight region, a width of about 0.2 inches (0.5cm) in the narrowest region, and a thickness of about 0.06 inches to about 0.1 inches (about 1.5mm to about 2.5 cm). These samples were then allowed to cure at room temperature for 24 hours, at 100 ℃ for 1 hour, or at 120 ℃ for 1 hour to fully cure prior to tensile testing. The samples were then conditioned at room temperature for 30 minutes before being subjected to tensile testing.

Tensile strength tests were carried out in an INSTRON Universal testing machine model 1122 (Instron corporation, Nuwood, Mass.), in accordance with ASTM D638-14 "Standard Test Method for Tensile Properties of Plastics. The chuck speed was 0.04 inches/minute (1 mm/min). The modulus is calculated from the slope of the linear portion of the stress-strain curve.

Thermal conductivity

For thermal conductivity measurement, a disc-shaped sample was prepared by pressing the mixed paste into a disc-shaped silicone rubber mold and then laminating with a release liner on both sides. The disk shape gives a sample diameter of 12.6mm and a thickness of 2.2 mm. The samples were then cured for 24 hours at room temperature, 15 hours at room temperature, or 1 hour at 100 ℃ to achieve full cure.

Specific heat capacity C was measured using a Q2000 differential scanning calorimeter (TA Instruments, Eden Prairie, MN, US) with sapphire as the method standard_p。

The sample density was determined using geometric methods. The weight (m) of the disc-shaped sample was measured using a standard laboratory balance, the diameter (d) of the disc was measured using a caliper, and the thickness (h) of the disc was measured using a Mitathyo micrometer. The density ρ is defined by ρ ═ m/(π. h. (d/2)²) And (6) calculating.

Thermal diffusivity, alpha (T), was measured using an LFA 467HYPERFLASH flash instrument (Netzsch Instruments, Burlington, MA, US) according to ASTM E1461-13 "Standard test method for measuring thermal diffusivity by flash method".

The thermal conductivity k is calculated from the thermal diffusivity, heat capacity and density measurements according to the following formula: k is alpha. C_pρ, where k is the thermal conductivity in W/(m K) and α is in mm²Thermal diffusivity in units of/s, C_pIs the specific heat capacity in J/K-g, and ρ is in g/cm³Is the density in units.

Dielectric breakdown strength

Dielectric Breakdown Strength measurements were performed according to ASTM D149-09(2013), "Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical insulation at Commercial Power Frequencies", using a model 6TC4100-10/50-2/D149 automatic Dielectric Breakdown tester (available from Phoenix Technologies, Accident, MD, US) designed specifically for testing DC Breakdown of 3-100kV and AC Breakdown in the 1-50kV, 60Hz range. Each measurement was performed while the sample was immersed in fluarinert FC-40 fluid (3M Corporation, Saint Paul, MN, US, st. The average breakdown strength is based on the average of measurements of up to 10 or more samples. Typically, a frequency of 60Hz and a ramp rate of 500 volts/second were used for these tests.

Resistivity of

Surface and volume resistivities were measured with a model 6517A electrometer (Keithley Instruments, Cleveland, OH, US) at a resolution of 100 nanoamperes and an applied voltage of 500 volts according to the procedure in ASTM D257-14, "Standard Test Methods for DC Resistance or conductivity of Insulating Materials," A Keithley Instruments for DC Resistance or conductivity of Insulating Materials. A Keithley model 8009 resistivity testing fixture was used with a compressible conductive rubber electrode and applied 1lb of electrode pressure over about 2.5 inches of electrode and sample. The sample was about 18 mils thick. The corresponding detection threshold for surface resistivity is about 1017 Ω. One measurement was taken for each sample and a 60 second charge time was used. High resistance sample PTFE, low resistance sample (high capacity carbon loaded Kapton) and medium resistance sample (paper) were used as material reference standards.

Weathering aging test

The weathering and hydrolytic stability cycles were carried out according to the BMW SAE PR308.2 "climate Test for Bonded Joints" standard. At least 5 specimens were tested and they were pre-cured at room temperature for at least 24 hours. A single test cycle comprises 7 steps: step 1: starting at 23 ℃ and 20% Relative Humidity (RH); step 2: ramping to 90 ℃ and 80% RH in 1 hour; and step 3: held at 90 ℃ and 80% RH for 4 hours; and 4, step 4: the system was cooled and dehumidified to 23 ℃ and 20% RH; and 5: the system was cooled to-30 ℃ over 1 hour; step 6: holding at-30 deg.C for 4 hr; and 7: the system was heated to 23 ℃ and 20% RH over 1 hour. 20 cycles are required to complete the burn-in test. Physical properties of the cured compositions were measured before and after PR308.2 cycles.

Rheological property of the polymer

For the time study, storage modulus (G ') and loss modulus (G') were measured using an oscillation mode of 100rad/s angular frequency at 25 ℃ with a 25mm parallel plate geometry at 1% strain on a Discovery HR-3 rheometer (TA Instruments, Wood Dale, IL, US) equipped with a forced convection oven attachment. The "open time" of the composition is defined as the time when G '═ 0.3MPa, and the "gel time" is defined as the time when G' ═ G ". Viscosity was measured using a 25mm parallel plate geometry at 25 ℃ on a Discovery HR-3 rheometer (TA Instruments, Wood Dale, IL, US) equipped with a forced convection oven attachment using a steady flow mode with shear rate sweeps of 0.0011/s to 1001/s.

Results

Table 4 summarizes part A and part B of example 5 (with 81.6 wt% filler) at 25 ℃ and 35 ℃ for 1 second^-1And 4 seconds^-1Viscosity at a shear rate of (a). Thixotropic/shear thinning behavior was observed for both part a and part B.

TABLE 4 viscosity (cps) of part A and part B of example 5

Table 5 summarizes the physical properties of the compositions that were fully cured at Room Temperature (RT), typically over two days, and then aged at high temperature and high humidity for 20 cycles using the PR308.2 standard conditions described above. CE1 shows increased elongation at break and decreased tensile strength after aging under PR308.2 test conditions; this is due to bond dissociation after exposure to temperature and humidity cycles. Samples that retain a high degree of initial tensile strength and OLS after temperature and humidity cycling and have little or no change in elongation at break after aging are herein interpreted as having good hydrolytic stability.

TABLE 5 hydrolytic stability after high humidity thermal cycling

Tables 6 and 7 summarize the physical properties of the compositions that were fully cured at Room Temperature (RT), typically more than two days, and then aged for 20 cycles at elevated temperature and humidity, or for 10 days at 40 ℃ and 95% Relative Humidity (RH), using the PR308.2 standard conditions described above. Table 6 lists the measured data. Table 7 lists the percentage of each property retained after aging relative to the property value measured directly after curing.

TABLE 6 hydrolytic stability

TABLE 7 hydrolytic stability

Table 8 summarizes open time and gel time for several exemplary compositions.

TABLE 8 open time and gel time

	Open time (minutes)	Gel time (minutes)
			Ex.1	32.7	37.2
Ex.2	19.6	23.9
			Ex.5	56.0	60.8
Ex.7	49.6	55.0
			Ex.8	65.1	71.6
Ex.9	8.2	8.9
			Ex.10	3.9	4.3
Ex.11	7.8	8.4

Table 9 summarizes the thermal properties of several exemplary compositions after 2 days of full cure at room temperature.

TABLE 9 thermal Properties

Table 10 summarizes the electrical properties of several exemplary compositions after 2 days of full cure at room temperature.

TABLE 10 dielectric breakdown Strength and resistivity

Various modifications and alterations to this disclosure will become apparent to those skilled in the art without departing from the scope and spirit of this disclosure. It should be understood that this disclosure is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the disclosure intended to be limited only by the claims set forth herein as follows. All references cited in this disclosure are incorporated by reference into this application in their entirety.