Two-component curable composition and cured product

Abstract

Provided are a two-component curable composition and a cured product obtained therefrom. The two-component curable composition includes: a liquid A that contains a reactive silyl group-containing polymer (A) having a poly(meth)acrylate skeleton, water (B), and a thermally conductive filler (C); and a liquid B that contains a catalyst (E), a plasticizer (F), and a thermally conductive filler (G).

Description

Two-component curable composition and cured product

[0001] This disclosure relates to a two-component curable composition and a cured product.

[0002] In recent years, the performance of electronic devices such as personal computers, mobile phones, Personal Digital Assistants (PDAs), and lighting and display devices such as light-emitting diodes (LEDs) and Electronic Luminescents (ELs) has improved remarkably, largely due to significant improvements in the performance of computing elements and light-emitting elements. Along with this improvement in performance, the amount of heat generated has also increased significantly, making heat dissipation in electronic devices, lighting, and display devices a critical issue. As a thermal countermeasure, a TIM (Thermal Interface Material; thermally conductive material) is used to transfer the heat generated by computing elements and light-emitting elements to a heat sink without loss, and to dissipate the heat through the heat sink. Examples of heat sinks include heat sinks, and examples of heat-generating elements include CPUs (Central Processing Units) and LSIs (large-scale integrations). Commonly used TIMs include thermal sheets, thermally conductive greases, and gap fillers. Gap fillers, which are initially paste-like and harden into a solid after application, are attracting attention.

[0003] As a TIM suitable for large-area applications, a thermally conductive curable composition is known in which the first part comprises a catalyst, a ceramic filler mixture, a low-volatile organic liquid, and water, and the second part comprises a silyl-modified reactive polymer, a specific amount of a low-volatile organic liquid, and a ceramic filler mixture (see Patent Document 1).

[0004] Patent Document 1: Japanese Patent No. 7460552 Patent Document 2: Japanese Patent Publication No. 2022-521790

[0005] One embodiment of this disclosure aims to solve the problem of providing a two-component curable composition and a cured product thereof that exhibits excellent stability after long-term storage.

[0006] This disclosure includes the following embodiments: <1> A two-component curable composition comprising: liquid A containing a reactive silyl group-containing polymer (A) having a poly(meth)acrylate skeleton, water (B), and a thermally conductive filler (C); and liquid B containing a catalyst (E), a plasticizer (F), and a thermally conductive filler (G). <2> The two-component curable composition according to <1>, wherein the catalyst (E) comprises a tin-based catalyst. <3> The two-component curable composition according to <1> or <2>, wherein liquid A comprises a plasticizer (D). <4> The two-component curable composition according to any one of <1> to <3>, wherein the plasticizer (F) comprises a polymer-based plasticizer. <5> The two-component curable composition according to <3> or <4>, wherein the plasticizer (D) comprises a pentaerythritol-based plasticizer. <6> A two-component curable composition according to any one of <1> to <5>, wherein liquid A contains water (B) in a proportion of 0.05% to 0.25% by mass based on the total mass of liquid A. <7> A two-component curable composition according to any one of <1> to <6>, wherein liquid A contains a reactive silyl group-containing polymer (A) in a proportion of 2% to 8% by mass based on the total mass of liquid A. <8> A two-component curable composition according to any one of <1> to <7>, wherein at least one of the thermally conductive filler (C) and thermally conductive filler (G) contains zinc oxide. <9> A two-component curable composition according to <8>, wherein zinc oxide is contained in a proportion of 2% to 18% by mass based on the total mass of the thermally conductive filler. <10> A cured product of the two-component curable composition according to any one of <1> to <9>.

[0007] According to one embodiment of the present disclosure, a two-component curable composition with excellent stability after long-term storage, and a cured product thereof are provided.

[0008] The following describes in detail the two-component curable composition and its cured product relating to this disclosure. In this disclosure, “~” representing a numerical range indicates a range that includes the numerical values ​​described as its upper and lower limits, respectively. Furthermore, if only the unit is described for the upper limit in a numerical range represented by “~”, it means that the lower limit also has the same unit. In this disclosure, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, the content or amount of such multiple substances present in the composition means the total content or amount of those multiple substances present in the composition. In numerical ranges described in stages in this disclosure, the upper or lower limit described in one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. In numerical ranges described in this disclosure, the upper or lower limit described in one numerical range may be replaced with the value shown in the examples.

[0009] In this disclosure, "(meth)acrylate" is a term used to encompass both acrylate and methacrylate. In this disclosure, each component in a composition means the total amount of the relevant substance present in the composition if multiple components of that component are present in the composition, unless otherwise specified. In this disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In this disclosure, "JIS" is used as an abbreviation for Japanese Industrial Standards. In this disclosure, molecular weight means weight-average molecular weight (Mw) and is a value measured by gel permeation chromatography (GPC).

[0010] (Two-component curable composition) The two-component curable composition according to this disclosure comprises a liquid A containing a reactive silyl group-containing polymer (A) having a poly(meth)acrylate skeleton, water (B), and a thermally conductive filler (C), and a liquid B containing a catalyst (E), a plasticizer (F), and a thermally conductive filler (G).

[0011] In the thermally conductive curable composition described in Patent Document 1, which uses a reactive silyl group-containing polymer as a heat dissipation material, there was a risk that the reaction rate would decrease significantly after long-term storage.

[0012] The two-component curable composition according to this disclosure has the above configuration and therefore exhibits excellent stability after long-term storage. "Long-term storage" refers to a period generally considered to be long-term storage, for example, at least six months. "Stability after long-term storage" means that the two-component curable composition can be used as a two-component curable composition after long-term storage, and specifically means that it has a viscosity that is usable and a practically appropriate curing rate after long-term storage.

[0013] The reason why the two-component curable composition according to this disclosure exhibits excellent long-term storage stability is not clear, but it is presumed that by including water (B) and catalyst (E) separately in liquid A and liquid B, and by using a specific reactive silyl group-containing polymer (A) and water (B) in the same place, and by giving each of liquid A and B a specific composition, the deactivation of the catalyst after long-term storage is suppressed, resulting in a two-component curable composition that is practically problem-free.

[0014] The following describes each component contained in the two-component curable composition relating to this disclosure.

[0015] <Solution A> The two-component curable composition according to this disclosure includes Solution A, which contains a reactive silyl group-containing polymer (A), water (B), and a thermally conductive filler (C).

[0016] <<Reactive silyl group-containing polymer (A)>> Solution A contains a reactive silyl group-containing polymer (A) having a poly(meth)acrylate skeleton (hereinafter also referred to as reactive silyl group-containing polymer (A)). It is preferable that the reactive silyl group-containing polymer (A) is included in Solution A.

[0017] In this disclosure, “polymer” means a compound having a weight-average molecular weight (Mw) of 1,000 or more. In this disclosure, the concept of “polymer” also includes so-called oligomers. In this disclosure, the concept of “polymer” also includes so-called copolymers.

[0018] The reactive silyl group-containing polymer (A) having a poly(meth)acrylate skeleton may have a reactive silyl group at a terminal and have poly(meth)acrylate in the skeleton. The term "terminal" includes one terminal and both terminals.

[0019] The reactive silyl group-containing polymer (A) may be a compound represented by general formula (1).

[0020]

[0021] In general formula (1), R １ represents a linear or branched hydrocarbon group having 1 to 4 carbon atoms. OR ２ represents a linear or branched alkoxy group having 1 to 4 carbon atoms. A comprises a structural unit represented by general formula (2). x is an integer of 1 to 3. n is 1 or 2.

[0022]

[0023] In general formula (2), R ３ represents hydrogen or a methyl group. R ４ is a hydrocarbon group. m is an integer.

[0024] In general formula (1), the moiety of general formula (3) is an alkoxysilyl group.

[0025]

[0026] As shown in formula (3), in the alkoxysilyl group, there are 0 hydrocarbon groups represented by R １ bonded to a Si atom, that is, the hydrocarbon group represented by R １ is not bonded to the Si atom, or 1 to 2 hydrocarbon groups represented by R １ are bonded to the Si atom, and 1 to 3 alkoxy groups represented by OR ２ are bonded to the Si atom. Poly(meth)acrylate is bonded to the Si atom as the main chain of the reactive silyl group-containing polymer (A).

[0027] In general formula (1), OR ２Regarding the number of alkoxy groups represented, from the viewpoint of curing speed, it is preferable to have 3, i.e., X = 3, and from the viewpoint of softening the hardness of the cured product after curing, it is preferable to have 2 or 1, i.e., X = 2 or 1. For the reasons above, it is more preferable that X = 2.

[0028] In the context of a two-component curable composition, "curing" or "curing" refers to a state in which the reaction proceeds through catalytic action when liquids A and B of the two-component curable composition are mixed, causing the composition to lose its fluidity and form a solid cured product with shape retention that is practically acceptable.

[0029] In general formula (1), R １ From the viewpoint of curing speed, linear hydrocarbon groups having 1 to 4 carbon atoms are preferred, and linear hydrocarbon groups having 1 or 2 carbon atoms are more preferred. １ Specifically, methyl groups, ethyl groups, propyl groups, or butyl groups are preferred, with methyl groups or ethyl groups being more preferred.

[0030] In general formula (1), OR ２ From the viewpoint of curing speed, a linear alkoxy group having 1 to 4 carbon atoms is preferred, and a linear alkoxy group having 1 or 2 carbon atoms is more preferred. ２ Specifically, a methoxy group, an ethoxy group, a propoxy group, or a butoxy group is preferred, with a methoxy group or an ethoxy group being more preferred.

[0031] In general formula (1), when n is 1, the reactive silyl group-containing polymer (A) is a polymer having a silyl group at one end, and when n is 2, the reactive silyl group-containing polymer (A) is a polymer having silyl groups at both ends. From the viewpoint of curing speed, it is preferable that n is 2, that is, that the polymer has silyl groups at both ends.

[0032] In general formula (2), m is not limited, and the value of m can be selected from a wide range.

[0033] As the reactive silyl group-containing polymer (A), commercially available products may be used. Examples of commercially available products include those under the trade name "KANEKA XMAP SA120S" (manufactured by Kaneka Corporation) and the trade name "KANEKA XMAP SA100S" (manufactured by Kaneka Corporation).

[0034] -Content- The content of the reactive silyl group-containing polymer (A) is preferably 2% by mass to 8% by mass, and more preferably 3% by mass to 7% by mass, relative to the total mass of the liquid A. The liquid A may contain one type of the reactive silyl group-containing polymer (A) alone, or may contain two or more types thereof.

[0035] From the viewpoint of stability after long-term storage, it is preferable that the liquid A does not contain a reactive silyl group-containing polymer having a polyether skeleton among reactive silyl group-containing polymers that do not have a poly(meth)acrylate skeleton. The term "does not contain" means that the content is 0% by mass, or the polymer is not contained in an amount that impairs the stability effect after long-term storage. Also, from the viewpoint of stability after long-term storage, it is preferable that the liquid B also does not contain a reactive silyl group-containing polymer having a polyether skeleton. From the viewpoint of stability after long-term storage, the two-part curable composition of the present disclosure preferably does not contain a reactive silyl group-containing polymer having a polyether skeleton.

[0036] From the viewpoints of mixing properties of the two liquids and coating performance, the reactive silyl group-containing polymer (A) is preferably a polymer having a molecular weight of 1,000 to 50,000.

[0037] <<Water>> The liquid A contains water (B).

[0038] From the viewpoint of stability after long-term storage of the two-part curable composition, the water (B) is preferably contained in a liquid different from the liquid containing the catalyst (E). From the viewpoint of promoting hydrolysis of the reactive silyl group-containing polymer (A), the water (B) is preferably contained in the same liquid as the reactive silyl group-containing polymer (A).

[0039] Water (B) is not limited, but from the viewpoint of the stability of the two-component curable composition after long-term storage, it is preferable that it has a low impurity content, and may be, for example, deionized water, distilled water, or desalted water.

[0040] -Content- From the viewpoint of the stability of the two-component curable composition after long-term storage, the water (B) content is preferably 0.05% to 0.25% by mass, and more preferably 0.07% to 0.23% by mass, based on the total mass of liquid A.

[0041] <<Thermal Conductivity Filler>> Solution A contains thermal conductivity filler (C). The thermal conductivity filler (C) contained in Solution A and the thermal conductivity filler (G) contained in Solution B described later may be the same thermal conductivity filler or they may be different thermal conductivity fillers. However, from the viewpoint of storage stability and mixability, it is preferable that the thermal conductivity fillers contained in Solution A and Solution B described later are the same thermal conductivity filler. Hereinafter, when thermal conductivity filler (C) and thermal conductivity filler (G) are not distinguished, they may be referred to as "thermal conductivity filler".

[0042] Identical thermal conductive fillers refer to those with exactly the same types and ratios of elements.

[0043] There are no particular restrictions on the thermally conductive filler, and known fillers used in TIM can be used. Examples include zinc oxide, alumina (i.e., aluminum oxide), magnesium oxide, aluminum hydroxide, boron nitride, aluminum nitride, and carbon. From the viewpoint of thermal conductivity and viscosity, it is preferable that the thermally conductive filler contains zinc oxide.

[0044] Preferably, at least one of the thermally conductive filler (C) and thermally conductive filler (G) contains zinc oxide.

[0045] The zinc oxide used as a thermally conductive filler is not particularly limited, and examples include zinc oxide (ZnO), which is commonly used as a thermally conductive filler.

[0046] The zinc oxide is preferably in the form of particles, and from the viewpoint of achieving both flexibility and high conductivity in the resulting cured product, particles with a volume-average particle diameter of 0.05 μm to 100 μm are preferred, and particles with a volume-average particle diameter of 0.1 μm to 50 μm are more preferred.

[0047] -Content- From the viewpoint of thermal conductivity, the content of the thermally conductive filler contained in liquid A is preferably 50% by mass or more, more preferably 70% to 98% by mass, and even more preferably 85% to 98% by mass, relative to the total mass of liquid A. Liquid A contained in the two-component curable composition may contain one type of thermally conductive filler alone, or it may contain two or more types.

[0048] When the thermally conductive filler contains zinc oxide, from the viewpoint of thermal conductivity, the zinc oxide content is preferably 2% to 18% by mass, and more preferably 3% to 17% by mass, based on the total mass of the thermally conductive filler. Liquid A or Liquid B contained in the two-component curable composition may contain zinc oxide alone or may contain two or more types. Note that "total mass of thermally conductive filler" means the sum of the total mass of thermally conductive filler contained in Liquid A and the total mass of thermally conductive filler contained in Liquid B.

[0049] The thermally conductive filler contained in solution A may contain alumina (i.e., aluminum oxide). The alumina used as a thermally conductive filler is not particularly limited, and any alumina commonly used as a thermally conductive filler (specifically, Al ２ O ３ Examples include the following. The liquid A contained in the two-component curable composition may contain alumina alone or two or more types.

[0050] The alumina contained in liquid A of the two-component curable composition is preferably in the form of particles, and in particular, from the viewpoint of balancing thermal conductivity and viscosity, it is preferable to contain spherical or polyhedral alumina particles.

[0051] The above volume-average particle diameter is calculated as the volume-average particle diameter (50% diameter) from the measured values ​​(volume distribution) measured at a laser wavelength of 405 nm using a particle size distribution analyzer (for example, Shimadzu Corporation, product name: Nanoparticle Diameter Distribution Analyzer SALD-7500nano).

[0052] The two-component curable composition according to this disclosure may contain a compound other than zinc oxide and alumina as a thermally conductive filler. Examples of compounds other than zinc oxide and alumina include magnesium oxide, aluminum hydroxide, aluminum nitride, boron nitride, and carbon.

[0053] <<Plasticizer>> Liquid A preferably contains a plasticizer (D) from the viewpoint of storage stability, specifically maintaining an appropriate viscosity. The plasticizer (D) contained in Liquid A is the same as the plasticizer (F) in Liquid B described below, and the preferred embodiment is also the same. Hereafter, when plasticizer (D) and plasticizer (F) are not distinguished, they may be referred to as "plasticizer".

[0054] If liquid A contains a plasticizer (D), the content of plasticizer (D) is preferably 10% by mass or less, and more preferably 8% by mass or less, relative to the total mass of liquid A. There is no particular lower limit, but it is preferably 0% by mass or more.

[0055] From the viewpoint of maintaining an appropriate viscosity, it is preferable that the plasticizer be included in both liquid A and liquid B. That is, in the two-component curable composition according to this disclosure, it is preferable that liquid A contains plasticizer (D) and liquid B contains plasticizer (F). From the viewpoint of maintaining an appropriate viscosity, it is preferable that plasticizer (D) contains a pentaerythritol-based plasticizer. "Pentaerythritol-based plasticizer" means a pentaerythritol ester that can be used as plasticizer (D).

[0056] <<Dispersant>> Solution A may contain a dispersant. Solution A and Solution B, described below, may each contain a dispersant. By including a dispersant in both Solution A and Solution B, the miscibility between Solution A and Solution B (hereinafter also simply referred to as "miscibility") is good, and curing defects are well suppressed.

[0057] The dispersants contained in Solution A and Solution B may be the same dispersant or different dispersants, but from the viewpoint of storage stability and mixability, it is preferable that they be the same dispersant.

[0058] There are no particular restrictions on the dispersants used, and examples include silane coupling agents, titanium coupling agents, anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, polymeric surfactants, alcohols, compounds having a carboxyl group (such as fatty acids), metal soaps, fatty acid oligomer compounds, fluorinated surfactants, and boron-based surfactants.

[0059] Preferably, at least one of solution A and solution B contains a silane-based coupling agent as a dispersant.

[0060] Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-isocyanatetopropyltriethoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0061] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyglycerin fatty acid esters, polyglycerin fatty acid esters, polyglycerin fatty acid ethers, polyglycerin monoalkyl ethers, sucrose fatty acid esters, polyoxyethylene alkylamines, polyethylene glycol polypropylene glycol block copolymers, acetylene glycol, and polyoxyethylene adducts of acetylene glycol.

[0062] Compounds having a carboxyl group are not particularly limited and may be fatty acids having one carboxyl group and one hydrocarbon group in one molecule, or compounds having two or more carboxyl groups in one molecule. Examples of compounds having a carboxyl group include aliphatic carboxylic acids, aromatic carboxylic acids, fatty acids having aliphatic hydrocarbon groups with 12 to 22 carbon atoms, and fatty acids having unsaturated hydrocarbon groups with 18 to 22 carbon atoms.

[0063] Examples of fatty acids having an aliphatic hydrocarbon group with 12 to 22 carbon atoms include stearic acid, palmitic acid, myristic acid, and lauric acid. Examples of fatty acids having an unsaturated hydrocarbon group with 18 to 22 carbon atoms include oleic acid and erucic acid.

[0064] Furthermore, examples of compounds having carboxyl groups include polycarboxylic acids (i.e., polycarboxylic acids) having two or more carboxyl groups in one molecule, such as oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, and adipic acid; polycarboxylic acid salts such as alkylamine salts, alkylammonium salts, polycarboxylic acid polyaminoamides, sodium polycarboxylic acid salts, ammonium polycarboxylic acid salts, and amino alcohol polycarboxylic acid salts; and polycarboxylic acid copolymers.

[0065] Examples of polycarboxylic acid compounds include alkylamine salts or alkylammonium salts of polycarboxylic acids, polyaminoamides of polycarboxylic acids, sodium salts of polycarboxylic acids, ammonium salts of polycarboxylic acids, and amino alcohol salts of polycarboxylic acids.

[0066] Examples of metal soaps include metal salts of higher fatty acids such as calcium stearate, potassium oleate, and calcium oleate.

[0067] <Liquid B> The two-component curable composition according to this disclosure comprises Liquid A and Liquid B, wherein Liquid B contains a catalyst (E), a plasticizer (F), and a thermally conductive filler (G).

[0068] <<Catalyst>> Solution B contains catalyst (E).

[0069] From the viewpoint of the stability of the two-component curable composition after long-term storage, it is preferable that the catalyst (E) be contained in a liquid different from the liquid containing water (B).

[0070] Catalyst (E) is added to promote the hydrolysis reaction of the alkoxy group in the silyl modified portion, i.e., the portion represented by the general formula (3) above, and to improve the curing rate.

[0071] As catalyst (E), any catalyst that has the function of promoting the hydrolysis reaction of alkoxy groups in the silyl group modification portion of the reactive silyl group-containing polymer (A) can be used. Specifically, catalyst (E) can be a metal compound, an amine compound, a carboxylic acid compound, etc. Among these, metal compounds are preferred as catalyst (E) from the viewpoint of catalytic activity. Examples of metal compounds include tin-based compounds containing tin, zirconium-based compounds containing zirconium, titanium-based compounds containing titanium, aluminum-based compounds containing aluminum, and bismuth-based compounds containing bismuth. Among these, tin-based compounds are preferred in terms of their high catalytic activity. Among tin-based compounds, dibutyltin-based compounds containing dibutyltin compounds and dioctyltin-based compounds containing dioctyltin compounds are more preferred, and dibutyltin-based compounds are even more preferred.

[0072] It is preferable to use a catalyst (E) that is relatively highly active. The more active a catalyst is, the more readily it reacts with water, and it is presumed that if the catalyst and water are present in the same system, the catalytic activity will decrease over time. In one embodiment of the present invention, since catalyst (E) is not present in the same liquid as water (B), a catalyst that is relatively highly active can be used.

[0073] -Content- From the viewpoint of curing speed, the content of catalyst (E) is preferably 0.2 parts by mass or more and 10 parts by mass or less, and more preferably 0.4 parts by mass or more and 8 parts by mass or less, per 100 parts by mass of reactive silyl group-containing polymer. From the viewpoint of storage stability, the content of catalyst (E) in liquid B is preferably 0.01% by mass to 2% by mass, and more preferably 0.02% by mass to 1% by mass, relative to the total mass of liquid B. Liquid B may contain one type of catalyst (E) alone, or it may contain two or more types.

[0074] <<Plasticizer>> Solution B contains a plasticizer (F). There are no particular restrictions on the plasticizer (F), and examples include polymers that can be used as a plasticizer (F), fatty acid ester compounds having unsaturated hydrocarbon groups, aromatic carboxylic acid ester compounds, as well as oils containing fatty acids and aromatic carboxylic acids having unsaturated hydrocarbon groups.

[0075] The plasticizer (F) preferably includes a polymer-based plasticizer. "Polymer-based plasticizer" means a polymer that can be used as the plasticizer (F).

[0076] Examples of polymers include acrylic polymers, polyester polymers, polyurethane polymers, and silicone polymers, but acrylic polymers are preferred from the viewpoint of heat resistance and flexibility of the resulting cured product.

[0077] When the plasticizer is a polymer, it is preferable that the polymer has a glass transition temperature of -20°C or lower, and more preferably an acrylic polymer with a glass transition temperature of -20°C or lower, from the viewpoint of the heat resistance and flexibility of the resulting cured product. The glass transition temperature (Tg) of the polymer can be determined by examining the inflection point of the DSC curve measured using a differential thermal analyzer (DSC).

[0078] Examples of fatty acid ester compounds having an unsaturated hydrocarbon group include palmitoleic acid, oleic acid, linoleic acid, linolenic acid, and pentaerythritol ester.

[0079] Examples of aromatic carboxylic acid ester compounds include ester compounds such as phthalic acid, terephthalic acid, benzoic acid, and trimellitic acid.

[0080] From the viewpoint of high-temperature stability, the plasticizer preferably contains an aromatic carboxylic acid ester compound, and more preferably contains a trimellitic acid ester.

[0081] -Content- The content of plasticizers (total amount if two or more types of plasticizers are included) is preferably 3% to 15% by mass, and more preferably 5% to 12% by mass, relative to the total mass of liquid B, from the viewpoint of achieving a balance between miscibility, heat resistance, and flexibility. Liquid B contained in the two-component curable composition may contain one type of plasticizer alone, or it may contain two or more types.

[0082] <<Thermal Conductivity Filler>> Solution B contains thermal conductivity filler (G). The thermal conductivity filler (G) contained in Solution B is the same as the thermal conductivity filler (C) contained in Solution A described above, and the preferred embodiment is the same.

[0083] The thermally conductive filler (G) contained in liquid B may be the same as the thermally conductive filler (C) contained in liquid A, or it may be different from the thermally conductive filler (C) contained in liquid A. However, from the viewpoint of storage stability and mixability, it is preferable that it be the same as the thermally conductive filler (C) contained in liquid A.

[0084] -Content- From the viewpoint of thermal conductivity, the content of the thermally conductive filler (G) contained in liquid B is preferably 50% by mass or more, more preferably 70% to 98% by mass, and even more preferably 85% to 98% by mass, relative to the total mass of liquid B.

[0085] <<Dispersant>> Solution B may contain a dispersant. The dispersant contained in Solution B is the same as the dispersant contained in Solution A described above, and the preferred embodiments other than the dispersant content are also the same. The dispersant contained in Solution B may be the same as the dispersant contained in Solution A, or it may be different. From the viewpoint of storage stability, it is preferable that the dispersant contained in Solution B is the same as the dispersant contained in Solution A.

[0086] <<Rheology Control Agent>> Solution B may contain a rheology control agent from the viewpoint of miscibility and storage stability.

[0087] In this context, rheology control agents refer to additives that impart non-Newtonian properties to changes in shear rate. Specifically, rheology control agents are additives that impart flow characteristics such as high shear viscosity in the low shear rate range and low shear viscosity in the high shear rate range.

[0088] The rheology control agent may be an inorganic compound-based rheology control agent or an organic compound-based rheology control agent. Examples of inorganic compound-based rheology control agents include fumed silica, bentonite, mica, and kaolin. Examples of organic compound-based rheology control agents include urea-modified polymers, urethane-modified polymers, castor oil wax, polyethylene wax, polyamide wax, and fatty acid amide wax. Among these, inorganic compound-based rheology control agents are preferred, with fumed silica or bentonite being more preferred, and bentonite being even more preferred. When using fumed silica, it is preferable to use fumed silica whose surface has been made hydrophobic by a silane coupling agent or other surface modifier. When using bentonite, organically modified bentonite, which has been organically modified by a quaternary ammonium salt or other organic modifier, is preferably used.

[0089] There are no particular restrictions on the amount of rheology control agent contained, and it can be set as appropriate.

[0090] <Other Matters Concerning Two-Component Curable Compositions> <<Other Additives>> The two-component curable composition according to this disclosure may contain, as necessary, components other than a reactive silyl group-containing polymer having a poly(meth)acrylate skeleton (A), water (B), thermally conductive filler (C) and thermally conductive filler (G), plasticizer (D) and plasticizer (F), catalyst (E), and rheology control agent (hereinafter also referred to as "other additives") in solution A and / or solution B. As other additives, additives such as corrosion inhibitors and rust inhibitors may be appropriately blended. The above additives may be used individually or in combination of two or more.

[0091] Examples of corrosion inhibitors include benzotriazole, toltriazole, thiadiazole, and benzimidazole.

[0092] Examples of rust inhibitors include metal sulfonate salt compounds and sorbitan compounds.

[0093] <Mass ratio of solution A to solution B> From the viewpoint of mixability and usability, the mass ratio of solution A to solution B is preferably 4:1 to 1:4 by mass, more preferably 2:1 to 1:2, and most preferably 1:1.

[0094] <<Shear Viscosity of Solution A and Solution B>> From the viewpoint of mixability and coating performance, the shear viscosities of Solution A and Solution B are preferably 100 Pa·s to 400 Pa·s, more preferably 100 Pa·s to 300 Pa·s, and even more preferably 100 Pa·s to 200 Pa·s, respectively. The above shear viscosity is measured using a viscoelasticity measuring device (for example, product name: MCR301, manufactured by Anton Paar) at a measurement temperature of 25°C and a shear rate of 10 s. －１ These are values ​​measured under the following conditions.

[0095] (Method for producing a two-component curable composition) The method for producing the two-component curable composition according to this disclosure is not particularly limited, and for example, it can be produced by the following method. A reactive silyl group-containing polymer (A), water (B), a thermally conductive filler (C), a plasticizer (D) if necessary, and other additives are placed in a stirring vessel and stirred and mixed to obtain liquid A, which is contained in the two-component curable composition according to this disclosure. A catalyst (E), a plasticizer (F), a thermally conductive filler (G), a rheology control agent if necessary, and other additives are placed in a stirring vessel and stirred and mixed to obtain liquid B, which is contained in the two-component curable composition according to this disclosure. Known stirrers and the like can be used for stirring and mixing.

[0096] In the method for producing a two-component curable composition according to this disclosure, when adding a rheology control agent and other additives, stirring is only required for a time sufficient for the rheology control agent and its additives to dissolve or disperse. Furthermore, there are no particular restrictions on the order in which the rheology control agent and other additives are added, and they can be set as appropriate. For example, the catalyst (E), plasticizer (F), and thermally conductive filler (G) may be added together to a stirring vessel along with the rheology control agent and other additives, or these raw materials may be divided into several portions in advance to prepare multiple mixtures, and then the multiple mixtures may be mixed with the rheology control agent and other additives.

[0097] (Cured Product) The cured product according to this disclosure is a cured product of the two-component curable composition according to this disclosure. There are no particular restrictions on the method of curing the two-component curable composition, but it is sufficient to mix liquid A and liquid B contained in the two-component curable composition according to this disclosure. There are no particular restrictions on the method of mixing liquid A and liquid B, and known stirrers and the like can be used. From the viewpoint of mixability and usability, the mixing ratio of liquid A and liquid B is preferably 4:1 to 1:4 by mass, more preferably 2:1 to 1:2, and most preferably 1:1. There are no particular restrictions on the temperature when mixing liquid A and liquid B (i.e., curing temperature), and it may be room temperature (25°C) or 10°C to 40°C. Furthermore, heating may be performed after mixing liquid A and liquid B contained in the two-component curable composition according to this disclosure. When heating, the heating temperature is preferably 60°C or higher, and more preferably 70°C or higher. The heating time is preferably 1 minute to 120 minutes.

[0098] The thermal conductivity of the cured product according to this disclosure is preferably 0.5 [W / (m·K)] to 50 [W / (m·K)], and more preferably 1 [W / (m·K)] to 20 [W / (m·K)], from the viewpoint of flexibility, shape stability, and suppression of changes in thermal conductivity.

[0099] Regarding the softness of the cured product according to this disclosure, from the viewpoint of stress relief to the surrounding parts of the cured product, the Asker C hardness is preferably 75 or less, more preferably 72 or less, and even more preferably 68 or less. Similarly, the Shore OO hardness is preferably 90 or less, and more preferably 86 or less. In this disclosure, the Asker C hardness is determined in accordance with JIS K 7312:1996, and the Shore OO hardness is determined in accordance with ASTM D2240.

[0100] <Applications> The two-component curable composition according to this disclosure can be suitably used, for example, as a TIM (Thermal Insulation) to fill recesses formed in a substrate (for example, the gap between a heating element and a heat sink).

[0101] The two-component curable compositions according to this disclosure will be described in detail below with reference to examples. However, the two-component curable compositions according to this disclosure are not limited in any way by these examples.

[0102] (Examples 1-2 and Comparative Examples 1-3) Each raw material was blended in the amounts (parts by mass) shown in Table 1, and mixed at 2,000 rpm (revolutions per minute) for 2 minutes under atmospheric pressure using a rotational / revolving mixer (manufactured by Thinky Co., Ltd., product name: Awatori Rentaro ARV-310) to prepare a two-component curable composition consisting of liquid A and liquid B.

[0103] The following evaluations were performed using the two-component curable compositions prepared in Examples 1-2 and Comparative Examples 1-3. The results are shown in Table 1.

[0104] -Evaluation- <Shear Viscosity> Shear viscosity was measured using a viscoelasticity measuring device (product name: MCR301, manufactured by Anton Paar) at a temperature of 25°C and a shear rate of 10 s. －１ The measurement was performed under the specified conditions. The measured value was defined as the initial shear viscosity.

[0105] <Thermal Conductivity> Thermal conductivity was measured in accordance with ISO 22007-2. The thermal conductivity measuring device used was the TPS2500S manufactured by Kyoto Electronics Manufacturing Co., Ltd.

[0106] <Shape Stability> - Asker C Hardness (Sample Thickness: 6 mm) - The Asker C hardness of the cured product of the curable composition was measured in accordance with JIS K 7312:1996. After mixing liquid A and liquid B in a mass ratio of 1:1, the curable composition was molded to 30 mm × 15 mm × 6 mm (thickness 6 mm) and cured at 25°C and 50% RH for 24 hours. The Asker C hardness of the obtained cured product was measured using an Asker rubber hardness meter Type C (manufactured by Polymer Instruments Co., Ltd.), and the measured values ​​are recorded in the "Hardness after Curing (Asker C)" column of Table 1. The smaller the Asker C hardness value, the easier it is to mitigate external forces and maintain a stable shape.

[0107] <Long-Term Storage Stability> -Shear Viscosity- Long-term storage was performed by storing each of the liquids A and B for 6 months under conditions of 25°C and 50% RH. The shear viscosity was measured for liquids A and B after long-term storage. The measured values ​​were defined as the shear viscosity after long-term storage. The measurement method was the same as that used for measuring the initial shear viscosity described above.

[0108] (Evaluation Criteria for Shear Viscosity After Long-Term Storage) The shear viscosity after long-term storage was evaluated by comparing the value of the shear viscosity after long-term storage with the value of the initial shear viscosity, according to the following criteria: A: The value of the shear viscosity after long-term storage is less than twice the value of the initial shear viscosity. B: The value of the shear viscosity after long-term storage is twice or more the value of the initial shear viscosity.

[0109] -Curing Speed- Long-term storage was performed by storing each of the liquids A and B for 6 months under conditions of 25°C and 50% RH. After long-term storage, the liquids A and B were mixed in a mass ratio of 1:1, and the curable composition was molded into a 30 mm x 15 mm x 6 mm (thickness 6 mm) and cured. The degree of curing was checked after 24 hours, and then every 24 hours thereafter.

[0110] Table 1 shows the time at which curing was confirmed. If curing was not confirmed after a certain period of time, the time at which curing was confirmed was noted with "or more" and recorded in Table 1. For example, if "120 or more" is written in Table 1, it means that curing was not confirmed after 120 hours. In Comparative Example 3, Solution A thickened, making it impossible to mix Solution A and Solution B. Therefore, in Table 1, "Not feasible due to thickening of Solution A" is written in the curing speed column for Comparative Example 3.

[0111] (Evaluation Criteria for Curing Speed ​​After Long-Term Storage) The curing speed after long-term storage was evaluated according to the following criteria: A: Curing was confirmed 24 hours after mixing liquid A and liquid B. B: Curing was not confirmed 24 hours after mixing liquid A and liquid B.

[0112] Details of the raw materials used, as listed in Table 1, are shown in Table 2 below. A "-" in Table 1 indicates that the corresponding ingredient is not present.

[0113]

[0114] As shown in Table 1, the two-component curable compositions of Example 1 and Example 2 demonstrated superior stability after long-term storage compared to the two-component curable compositions of Comparative Examples 1 to 3. Specifically, it was demonstrated that they possessed sufficient viscosity and an appropriate curing rate for use as two-component curable compositions after storage for at least six months.

[0115] The disclosure of Japanese Patent Application No. 2025-057242, filed on 28 March 2025, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

Claims

1. A two-component curable composition comprising: liquid A containing a reactive silyl group-containing polymer (A) having a poly(meth)acrylate skeleton, water (B), and a thermally conductive filler (C); and liquid B containing a catalyst (E), a plasticizer (F), and a thermally conductive filler (G).

2. The two-component curable composition according to claim 1, wherein the catalyst (E) comprises a tin-based catalyst.

3. The two-component curable composition according to claim 1, wherein the liquid A comprises a plasticizer (D).

4. The two-component curable composition according to claim 1, wherein the plasticizer (F) comprises a polymer-based plasticizer.

5. The two-component curable composition according to claim 3, wherein the plasticizer (D) comprises a pentaerythritol-based plasticizer.

6. The two-component curable composition according to claim 1, wherein the liquid A contains water (B) in a proportion of 0.05% to 0.25% by mass based on the total mass of the liquid A.

7. The two-component curable composition according to claim 1, wherein the liquid A contains the reactive silyl group-containing polymer (A) in a proportion of 2% to 8% by mass based on the total mass of the liquid A.

8. The two-component curable composition according to claim 1, wherein at least one of the thermally conductive filler (C) and the thermally conductive filler (G) contains zinc oxide.

9. The two-component curable composition according to claim 8, wherein the zinc oxide is contained in a proportion of 2% to 18% by mass based on the total mass of the thermally conductive filler.

10. A cured product of a two-component curable composition according to any one of claims 1 to 9.

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