Curable composition and heat-dissipating member

Abstract

Provided is a curable composition containing a polyol, a polyisocyanate, and an inorganic filler, wherein: the polyol contains a polyether polyol containing one or more selected from the group consisting of an oxyethylene group and an oxypropylene group, and also having a number-average molecular weight of 1,100 or more; the content of the polyether polyol in 100 mass% of the polyol is 55 mass% or more; and the content of the inorganic filler in 100 mass% of the curable composition is 50-90 mass%.

Description

Curable composition and heat dissipating member

[0001] The present invention relates to a curable composition and a heat dissipating member.

[0002] Known materials for dissipating heat generated by heat-generating elements such as semiconductor devices and lithium-ion batteries to the outside of the heat-generating elements include silicone compositions containing silicone and inorganic fillers, acrylic compositions containing acrylic resins and inorganic fillers, and urethane compositions containing urethane raw materials and inorganic fillers. Among these, silicone compositions suffer from poor electrical conductivity due to low-molecular-weight siloxanes in the composition. Acrylic compositions suffer from the problem of being unable to conform to the unevenness of the coated surface due to their high hardness, which may result in insufficient heat dissipation. In contrast, urethane compositions have low hardness and can conform to the unevenness of the coated surface, making them excellent materials for heat dissipation. Patent Document 1 discloses a curable composition containing a polyol, a polyisocyanate, an inorganic filler dispersant, and an inorganic filler, wherein the polyol contains 50% by mass or more of a polyalkylene glycol having a chemical formula weight or number-average molecular weight of 1,000 or less, based on the weight of the polyol. Patent Document 2 discloses a two-component urethane composition comprising an ester-based polyol resin-containing main composition part; a polyisocyanate-containing curing agent composition part; a filler; and a phosphate ester-based anionic dispersant, wherein the anionic dispersant is contained in an amount of less than 20 parts by weight per 100 parts by weight of the ester-based polyol resin and polyisocyanate combined.

[0003] International Publication No. 2021 / 261519 Special Publication No. 2020-533440

[0004] Patent Document 1 aims to provide a urethane resin with excellent thermal conductivity and flexibility, but does not address the issue of breaking elongation, nor has it been studied. Therefore, the present inventors' investigations revealed that the curable composition described in Patent Document 1 had insufficient breaking elongation. Patent Document 2 aims to provide a resin composition for a battery module with excellent heat dissipation, adhesive strength, cold resistance, heat resistance, insulating properties, and adhesive reliability, but does not address the issue of breaking elongation, nor has it been studied. Therefore, the present inventors' investigations revealed that the curable composition described in Patent Document 2 had high hardness and insufficient breaking elongation. If the breaking elongation is insufficient, as in the compositions of Patent Documents 1 and 2, when a heating element moves due to vibration or the like, the composition does not follow the movement and therefore cannot maintain adhesion, resulting in reduced heat dissipation properties (thermal conductivity and breaking elongation). The present invention aims to provide a curable composition and a heat dissipation member that can yield a cured product with excellent heat dissipation properties (thermal conductivity and breaking elongation).

[0005] As a result of intensive research, the present inventors have found that a cured product having excellent heat dissipation properties (thermal conductivity and elongation at break) can be obtained by using a urethane-based curable composition in which the content of a polyether polyol containing at least one of an oxyethylene group and an oxypropylene group and having a number average molecular weight of at least 1,100 is 55% by mass or more relative to the total amount of polyol. The present invention was completed based on these findings.

[0006] The present invention provides the following means. [1] A curable composition comprising a polyol, a polyisocyanate, and an inorganic filler, wherein the polyol comprises a polyether polyol containing one or more groups selected from the group consisting of an oxyethylene group and an oxypropylene group and having a number average molecular weight of 1,100 or more, wherein a content of the polyether polyol in 100% by mass of the polyol is 55% by mass or more, and a content of the inorganic filler in 100% by mass of the curable composition is 50 to 90% by mass. [2] The curable composition according to [1] above, wherein a proportion of the oxyethylene groups in 100% by mass of the total amount of the polyether polyol is 0% to 95% by mass. [3] The curable composition according to [1] or [2] above, wherein the polyisocyanate is one or more groups selected from the group consisting of an aliphatic polyisocyanate, an alicyclic polyisocyanate, and an aromatic polyisocyanate. [4] The curable composition according to any one of [1] to [3] above, further comprising a urethanization catalyst. [5] The curable composition according to any one of [1] to [4] above, wherein the polyol further comprises an amine polyol obtained by polymerizing an alkylene oxide with an initiator having an amino group. [6] The curable composition according to [5] above, wherein the content of the amine polyol is 3 to 40 mass% relative to 100 mass% of the polyol. [7] The curable composition according to any one of [1] to [6] above, wherein the inorganic filler is a metal, a metal oxide, a metal nitride, a metal hydroxide, or a metal carbonate. [8] The curable composition according to any one of [1] to [7] above, which is used for a heat-dissipating member. [9] A heat-dissipating member comprising a cured product of the curable composition according to any one of [1] to [8] above.

[0007] According to the present invention, it is possible to provide a curable composition and a heat dissipating member that can give a cured product having excellent heat dissipation properties (thermal conductivity and elongation at break).

[0008] The definitions and meanings of terms and notations used in this specification are shown below. The number average molecular weight (Mn) is the polystyrene-equivalent molecular weight determined by gel permeation chromatography (GPC) based on a calibration curve prepared using a standard polystyrene sample. The hydroxyl value is determined by measurement in accordance with Method B (automatic potentiometric titration) of JIS K 1557-1:2007. The isocyanate index means the following: Isocyanate index = [NCO number] / [OH number] x 100 NCO number: total number of moles of isocyanate groups in the polyisocyanate OH number: total number of moles of hydroxyl groups in the polyol Ethylene oxide (EO) units, propylene oxide (PO) units, and alkylene oxide (AO) units mean units derived from EO, units derived from PO, and units derived from AO. Similarly, X units mean units derived from compound X.

[0009] [Curable Composition] The curable composition according to the present embodiment is a curable composition comprising a polyol, a polyisocyanate, and an inorganic filler, wherein the polyol comprises a polyether polyol containing at least one selected from the group consisting of an oxyethylene group and an oxypropylene group and having a number average molecular weight of 1,100 or greater, wherein the content of the polyether polyol relative to 100% by mass of the polyol is 55% by mass or greater, and wherein the content of the inorganic filler relative to 100% by mass of the curable composition is 50 to 90% by mass. The curable composition according to the present embodiment can provide a cured product with excellent heat dissipation properties (thermal conductivity and elongation at break). While the details of the reason for this are unclear, it is presumed to be as follows. Generally, resins have low thermal conductivity, so inorganic fillers are blended into the curable composition to increase the thermal conductivity of the cured product of the curable composition. The curable composition according to this embodiment is believed to have achieved high thermal conductivity due to the flexibility of the resin, which increased the number of contact points between the inorganic fillers and formed sufficient paths for heat transmission. Furthermore, to improve the heat dissipation properties of the cured product of the curable composition, it is desirable for the inorganic filler to penetrate firmly into the surface irregularities of the heat dissipation component. Therefore, a cured product of a curable composition containing an inorganic filler must be able to tightly bond a heat source, such as a battery housing, to a heat sink, be sufficiently flexible to accommodate vibrations, and have high elongation at break. The polyol contains a polyether polyol containing at least one group selected from the group consisting of oxyethylene groups and oxypropylene groups and having a number-average molecular weight of 1,100 or more. By providing a polyether polyol content of 55% by mass or more relative to 100% by mass of the polyol, the composition exhibits appropriate flexibility and crosslinkability, resulting in a high elongation at break as a cured product. The flexibility described in Patent Document 1 simply refers to the surface hardness of the composition after curing. In contrast, the elongation at break in this invention refers to the amount of deformation under tension. As described above, the flexibility described in Patent Document 1 and the elongation at break in the present invention are different physical properties, and in a cured product of the curable composition, flexibility and elongation at break do not necessarily correlate with each other.For example, if the cured product exhibits mechanical properties that make it prone to rupture or is highly brittle, it will have high flexibility (low hardness) but low elongation at break.

[0010] (Polyol) The polyol contains a polyether polyol (A1) described below as an essential component. The polyol may also contain, as optional components, one or more of an amine polyol (A2) described below, an aliphatic polyhydric alcohol (A3) having an Mn of less than 1,000 described below, and other polyols described below. From the viewpoint of improving curability and obtaining a cured product with excellent heat dissipation properties (thermal conductivity and elongation at break), the content of the polyol in 100% by mass of the curable composition is preferably 1 to 20% by mass, more preferably 2 to 18% by mass, and even more preferably 2 to 10% by mass.

[0011] <Polyether Polyol (A1)> The polyol contains a polyether polyol (A1) containing one or more groups selected from the group consisting of oxyethylene groups and oxypropylene groups and having a number-average molecular weight of 1,100 or more. The polyether polyol (A1) may be used singly or in combination of two or more types. The proportion of the oxyethylene groups in 100% by mass of the total amount of polyether polyol (A1) is preferably 0% to 95% by mass. This improves curability and allows for the production of a cured product with excellent heat dissipation properties (thermal conductivity and elongation at break). Furthermore, the polyether polyol (A1) may contain an oxypropylene group. This results in an appropriate curing rate and allows for the production of a cured product suitable for use as a heat dissipation material. From this perspective, the proportion of the oxyethylene groups in 100% by mass of the total amount of polyether polyol (A1) is more preferably 9 to 95% by mass, even more preferably 9 to 90% by mass. The proportion of the oxypropylene groups in the total amount of oxyalkylene groups (100% by mass) is preferably 5 to 100% by mass, and more preferably 5 to 91% by mass.

[0012] Examples of the polyether polyol (A1) include AO addition polymers obtained by ring-opening addition polymerization of an alkylene oxide (AO) containing at least one of ethylene oxide (EO) and propylene oxide (PO) with a polyhydric alcohol as an initiator. The proportion of the EO units in 100% by mass of the total polyether polyol (A1) is preferably 0% to 95% by mass, more preferably 9 to 95% by mass, and even more preferably 9 to 90% by mass. The proportion of the PO units in 100% by mass of the total polyether polyol (A1) is preferably 5 to 100% by mass, more preferably 5 to 91% by mass. The total amount of EO units and PO units in 100% by mass of the total AO units is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, and even more preferably 95 to 100% by mass. When the total amount of EO units and PO units is 80% by mass or more relative to 100% by mass of the total amount of AO units, the resulting cured product has excellent heat dissipation properties (thermal conductivity and elongation at break) and an appropriate curing rate, making it possible to obtain a cured product suitable for use as a heat dissipation material.

[0013] When two or more alkylene oxides are subjected to ring-opening addition, the arrangement of units derived from each alkylene oxide may be random, block, or tapered. When the arrangement of EO units and PO units is random, the copolymer may typically have a block of PO units and a random of EO units and PO units, or a block of EO units and a random of EO units and PO units. When the arrangement of EO units and PO units is block, the copolymer may have a block of PO units, a block of EO units, and a block of PO units in this order (a "PO block-EO block-PO block" structure), or a block of EO units, a block of PO units, and a block of EO units in this order (a "EO block-PO block-EO block" structure). Furthermore, when the arrangement of EO units and PO units is tapered, the composition usually contains blocks of PO units, random units of EO units and PO units, and blocks of EO units.

[0014] The content of EO units relative to the total amount of AO units present in the polyether polyol (A1) is１３ It can be calculated by determining the monomer unit composition of the oxyalkylene chain using C-NMR. For example, when the polyether polyol (A1) is a polyol consisting of PO units and EO units, the EO unit content can be determined from the area ratio of the signal of the methyl group in the PO unit to the signal of the methylene group in the PO unit and the EO unit. It is also possible to calculate the content of AO units, such as PO units and EO units, present in the resulting polyether polyol (A1) from the amount of each AO charged when producing the polyether polyol (A1).

[0015] Examples of polyhydric alcohol initiators include dihydric alcohols such as water, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,4-butanediol, and 1,6-hexanediol; trihydric alcohols such as glycerin, trimethylolpropane, and 1,2,6-hexanetriol; tetrahydric alcohols such as pentaerythritol, diglycerin, tetramethylolcyclohexane, and methyl glucoside; hexahydric alcohols such as sorbitol, mannitol, and dulcitol; and octahydric alcohols such as sucrose. Of these, dipropylene glycol and glycerin are preferred from the viewpoints of excellent flexibility and good elongation at break.

[0016] Amine polyols using an amine compound as an initiator and polyols having an amino group are not included in the polyether polyol (A1). The total amount of units derived from the polyhydric alcohol initiator and AO units in the polyether polyol (A1) is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, still more preferably 99% by mass or more, and may even be 100% by mass.

[0017] The number average molecular weight (Mn) of the polyether polyol (A1) is 1,100 or more. When it is 1,100 or more, the breaking elongation is improved, and a cured product with excellent heat dissipation properties can be obtained. Furthermore, from the viewpoint of curability, the Mn of the polyether polyol (A1) is preferably 20,000 or less. From these viewpoints, the Mn of the polyether polyol (A1) is preferably 1,100 to 20,000, more preferably 1,100 to 12,000, even more preferably 1,100 to 10,000, and even more preferably 1,100 to 5,000.

[0018] The content of polyether polyol (A1) in 100% by mass of polyol is 55% by mass or more. When the content is 55% by mass or more, the elongation at break of the cured product of the curable composition is improved, and as a result, a cured product with excellent heat dissipation properties can be obtained. Furthermore, the content of polyether polyol (A1) in 100% by mass of polyol may be 100% by mass, but from the viewpoint of achieving the effects attributable to polyols other than polyether polyol (A1), the content of polyether polyol (A1) is preferably 95% by mass or less. From these viewpoints, the content of polyether polyol (A1) in 100% by mass of polyol is preferably 55 to 95% by mass, more preferably 57 to 85% by mass, even more preferably 60 to 85% by mass, even more preferably 70 to 80% by mass, and even more preferably 73 to 78% by mass.

[0019] The polyether polyol (A1) can be produced by a known method, for example, by adding AO to the polyhydric alcohol as the initiator by a known method. By adjusting the amount of AO used, the number average molecular weight can be made 1,100 or more.

[0020] <Amine polyol (A2)> Examples of the amine polyol (A2) include polyether polyols obtained by ring-opening addition polymerization of alkylene oxide (AO) using an amine compound as an initiator. The amine polyol (A2) enhances the activity of the urethane reaction and contributes to improving curability. The amine polyol (A2) may be used alone or in combination of two or more.

[0021] Examples of the amine compound as an initiator include aliphatic amine compounds such as alkanolamines (monoethanolamine, diethanolamine, triethanolamine, etc.) and alkylamines (ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine); saturated cyclic amine compounds such as N-aminomethylpiperazine and N-(2-aminoethyl)piperazine; and aromatic amine compounds such as aniline, tolylenediamine (2,4-diaminotoluene, etc.), xylylenediamine, diphenylmethanediamine, etc. From the viewpoint of the effect of increasing the initial activity of the urethanization reaction, aliphatic amine compounds or saturated cyclic amine compounds are preferred, and monoethanolamine or tolylenediamine is more preferred.

[0022] Examples of alkylene oxides used in the production of amine polyol (A2) include ethylene oxide (EO), propylene oxide (PO), butylene oxide, etc. It is preferable to use propylene oxide alone or a combination of ethylene oxide and propylene oxide. When used in combination, ethylene oxide and propylene oxide may be mixed and then reacted, or may be reacted sequentially.

[0023] The proportion of the PO units in 100% by mass of the total amount of the amine polyol (A2) is preferably 50 to 100% by mass, more preferably 80 to 100% by mass. The proportion of the EO units in 100% by mass of the total amount of the amine polyol (A2) is preferably 0 to 50% by mass, more preferably 0 to 20% by mass.

[0024] The number of hydroxyl groups in the amine polyol (A2) is preferably 2 to 6, more preferably 3 to 6, and particularly preferably 3 to 4. When the hydroxyl group number is equal to or greater than the lower limit of the above range, the viscosity is likely to be kept low, and therefore the viscosity when an inorganic filler is mixed can be reduced. From the viewpoint of the curability of the curable composition, the number average molecular weight (Mn) of the amine polyol (A2) is preferably 100 to 3,000, more preferably 200 to 2,000, even more preferably 300 to 1,000, and still more preferably 300 to 500.

[0025] From the viewpoint of improving the curability of the curable composition and obtaining a cured product excellent in heat dissipation properties (thermal conductivity and elongation at break), the content of the amine polyol (A2) in 100% by mass of polyol is preferably 3 to 40% by mass, more preferably 4 to 40% by mass, even more preferably 5 to 35% by mass, still more preferably 10 to 35% by mass, still more preferably 20 to 35% by mass, still more preferably 20 to 30% by mass, and still more preferably 20 to 27% by mass.

[0026] <Aliphatic polyhydric alcohol (A3) having Mn of less than 1,100> The polyol may or may not contain an aliphatic polyhydric alcohol (A3) having Mn of less than 1,100. The inclusion of the aliphatic polyhydric alcohol (A3) has the effect of reducing viscosity. The aliphatic polyhydric alcohol (A3) may be used alone or in combination of two or more. Examples of the aliphatic polyhydric alcohol (A3) having an Mn of less than 1,100 include dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,4-butanediol, and 1,6-hexanediol; trihydric alcohols such as glycerin, trimethylolpropane, and 1,2,6-hexanetriol; tetrahydric alcohols such as pentaerythritol, diglycerin, tetramethylolcyclohexane, and methyl glucoside; hexahydric alcohols such as sorbitol, mannitol, and dulcitol; and octahydric alcohols such as sucrose. Of these, propylene glycol and glycerin are preferred, and propylene glycol is more preferred.

[0027] From the viewpoint of exhibiting the effects of the polyether polyol (A1) and the amine polyol (A2), the content of the aliphatic polyhydric alcohol (A3) having an Mn of less than 1,100 in 100% by mass of polyol is preferably 0 to 25% by mass, more preferably 0 to 20% by mass, even more preferably 0 to 15% by mass, still more preferably 0 to 10% by mass, still more preferably 0 to 5% by mass, still more preferably 0 to 1% by mass, and still more preferably 0% by mass.

[0028] <Other Polyols> The polyol may or may not contain other polyols that do not fall into any of the three types of the polyether polyol (A1), the amine polyol (A2), and the aliphatic polyhydric alcohol (A3) having an Mn of less than 1,100. Only one type of other polyol may be used, or two or more types may be used in combination. Examples of other polyols include polyether polyols, polyester polyols, polycarbonate polyols, acrylic polyols, castor oil-based polyols, and polytetramethylene ether glycols. The content of other polyols in 100% by mass of the total amount of polyols is preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, and even more preferably 5% by mass or less, and may even be 0% by mass.

[0029] The composition may or may not contain a polyether polyol (A4-1) having an Mn of less than 1,100 as the other polyol. The content of the polyether polyol (A4-1) in 100% by mass of the total amount of polyols is 45% by mass or less. This allows the content of the polyether polyol (A1) to be 55% by mass or more, and a cured product with excellent heat dissipation properties (thermal conductivity and elongation at break) can be obtained. Examples of the polyether polyol (A4-1) include polyether polyols obtained by addition polymerization of an alkylene oxide (hereinafter referred to as AO) having 2 to 4 carbon atoms to an aliphatic polyhydric alcohol having 2 to 20 carbon atoms. Examples of the aliphatic polyhydric alcohol having 2 to 20 carbon atoms include dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,4-butanediol, and 1,6-hexanediol; trihydric alcohols such as glycerin, trimethylolpropane, and 1,2,6-hexanetriol; tetrahydric alcohols such as pentaerythritol, diglycerin, tetramethylolcyclohexane, and methyl glucoside; hexahydric alcohols such as sorbitol, mannitol, and dulcitol; and octahydric alcohols such as sucrose, with ethylene glycol and propylene glycol being preferred, and ethylene glycol being more preferred. Examples of AO include ethylene oxide, 1,2- or 1,3-propylene oxide, and 1,2-, 1,3-, 1,4-, or 2,3-butylene oxide, preferably ethylene oxide, 1,2-, or 1,3-propylene oxide, and more preferably 1,2- or 1,3-propylene oxide. Two or more of these AOs may be used in combination, and when two or more of them are used in combination, the bonding mode of the AOs may be any of block addition, random addition, and a combination of these.

[0030] The content of polyether polyol (A4-1) in 100% by mass of the total amount of polyols is 45% by mass or less, preferably 30% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and may be 0% by mass.

[0031] The polyether polyol (A4-1) can be produced by a known method, for example, by adding AO to the above-mentioned aliphatic polyhydric alcohol having 2 to 20 carbon atoms by a known method. By adjusting the amount of AO used, the number average molecular weight can be made less than 1,100.

[0032] As the polyether polyol (A4-1), commercially available products can be used, and preferred examples include Sannix PP-200 [polypropylene glycol having Mn=200, manufactured by Sanyo Chemical Industries, Ltd.], Sannix PP-400 [polypropylene glycol having Mn=400, manufactured by Sanyo Chemical Industries, Ltd.], Sannix PP-600 [polypropylene glycol having Mn=600, manufactured by Sanyo Chemical Industries, Ltd.], and Sannix PP-950 [polypropylene glycol having Mn=950, manufactured by Sanyo Chemical Industries, Ltd.]. The polyether polyol (A4-1) may be used alone or in combination of two or more. Examples of the polyether polyol (A4-1) include polyether polyols, polyester polyols, polycarbonate polyols, and acrylic polyols.

[0033] (Polyisocyanate) Examples of polyisocyanates include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and isocyanurates of these polyisocyanates. Only one type of polyisocyanate may be used, or two or more types may be used in combination.

[0034] Examples of the aliphatic polyisocyanate include chain aliphatic polyisocyanates having 4 to 20 carbon atoms, and preferred examples include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate.

[0035] Examples of the alicyclic polyisocyanate include alicyclic polyisocyanates having 6 to 17 carbon atoms, and preferred examples include isophorone diisocyanate (IPDI), 4,4-dicyclohexylmethane diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexene-1,2-dicarboxylate, and 2,5- or 2,6-norbornane diisocyanate. Alicyclic polyisocyanates are commercially available as Desmodur I (Sumika Covestro Urethane Co., Ltd.), etc.

[0036] Examples of aromatic polyisocyanates include aromatic polyisocyanates having 8 to 22 carbon atoms, and preferably 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), 4,4'- or 2,4'-diphenylmethane diisocyanate (monomeric MDI), polynuclear monomers of monomeric MDI (polymethylene polyphenyl polyisocyanate, polymeric MDI), polyol-modified MDI, m- or p-isocyanatophenylsulfonyl isocyanate, and the like. cyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, m- or p-isocyanatophenylsulfonyl isocyanate, m- or p-xylylene diisocyanate (XDI), trimethylolpropane adduct of XDI, and α,α,α',α'-tetramethylxylylene diisocyanate (TMXDI).

[0037] Examples of the isocyanurate of polyisocyanate include trimers of polyisocyanates (such as the above-mentioned aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates). The isocyanurate of polyisocyanate is commercially available as TLA-100 (Asahi Kasei Corporation), etc.

[0038] Among polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, isocyanurates of aliphatic polyisocyanates, and isocyanurates of alicyclic polyisocyanates are preferred from the viewpoint of excellent moldability, and monomeric MDI and polymeric MDI are more preferred from the viewpoint of improving curability, with polymeric MDI being even more preferred. Since MDI has an isocyanate group directly bonded to an aromatic ring, which is an electron-withdrawing group, the reactivity of the isocyanate group is very high, thereby further improving curability. Among these, polymeric MDI is preferred because it is relatively inexpensive and easy to handle. One type of polyisocyanate may be used alone, or two or more types may be used in combination.

[0039] The content of the polyisocyanate in 100% by mass of the curable composition is preferably 0.5 to 20% by mass, more preferably 1 to 10% by mass, and even more preferably 1.5 to 4% by mass, from the viewpoint of improving curability and obtaining a cured product having excellent heat dissipation properties (thermal conductivity and elongation at break). The total content of the polyol and the polyisocyanate in 100% by mass of the curable composition is preferably 3 to 30% by mass, more preferably 5 to 25% by mass, and even more preferably 5.5 to 10% by mass, from the viewpoint of improving curability and obtaining a cured product having excellent heat dissipation properties (thermal conductivity and elongation at break).

[0040] The isocyanate index, as shown by the following formula, is preferably 20 to 110. Isocyanate index = [NCO number] / [OH number] × 100, where NCO number is the total number of moles of isocyanate groups in the polyisocyanate and OH number is the total number of moles of hydroxyl groups in the polyol. When the isocyanate index is within the above range, the curability of the curable composition and the flexibility of the cured product are good. From this viewpoint, the isocyanate index is more preferably 40 to 110, even more preferably 40 to 100, still more preferably 50 to 100, even more preferably 70 to 100, and even more preferably 75 to 85.

[0041] (Inorganic filler) Examples of inorganic fillers include silicates (talc, clay, mica, and glass, etc.), metal oxides (titanium oxide, alumina, silica, zinc oxide, and magnesium oxide, etc.), metal carbonates (calcium carbonate, magnesium carbonate, and hydrotalcite, etc.), metal hydroxides (aluminum hydroxide, magnesium hydroxide, and calcium hydroxide, etc.), metal (sulfite) salts (barium sulfate, calcium sulfate, and calcium sulfite, etc.), metal borates (zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate, etc.), metal nitrides (aluminum nitride, boron nitride, and silicon nitride, etc.), and metals (gold, silver, copper, and alloys containing these, etc.).The inorganic filler may be used alone or in combination of two or more.

[0042] From the viewpoint of achieving good heat dissipation when a cured product of the curable composition is used as a heat dissipation member, the inorganic filler is preferably a metal, a metal oxide, a metal nitride, a metal hydroxide, or a metal carbonate, more preferably a metal oxide, even more preferably zinc oxide or alumina, and even more preferably alumina. These may be used alone or in combination of two or more.

[0043] The shape of the inorganic filler is not particularly limited, and fibrous and particulate inorganic fillers can be preferably used. In the case of particles, spherical, plate-like, needle-like, or irregularly shaped particles (obtained by crushing, etc.) can be used. From the viewpoint of excellent moldability, spherical particles are preferred as the shape of the inorganic filler.

[0044] When the inorganic filler is a spherical particle, the volume average particle diameter [D50: particle diameter at which the cumulative particle amount in the particle size distribution on a volume basis becomes 50%] of the inorganic filler is preferably 0.01 to 200 μm, more preferably 0.1 to 150 μm, and even more preferably 0.1 to 100 μm, from the viewpoint of excellent moldability. The volume average particle diameter of the inorganic filler can be measured using a laser diffraction particle size distribution measuring device [SALD-2000A, SALD-2300 manufactured by Shimadzu Corporation, LA-920 manufactured by Horiba, Ltd., etc.]. When components other than the inorganic filler are dissolved in a solvent, a solution of the composition may be measured.

[0045] The content of the inorganic filler in 100% by mass of the curable composition is 50 to 90% by mass. When the content is 50% by mass or more, the thermal conductivity of the cured product of the curable composition can be improved, and when the content is 90% by mass or less, the moldability can be improved. From this viewpoint, the content of the inorganic filler in 100% by mass of the curable composition is preferably 54 to 90% by mass, more preferably 60 to 90% by mass, even more preferably 70 to 90% by mass, and even more preferably 80 to 90% by mass. Furthermore, the content of the inorganic filler per 100 parts by mass of polyol is preferably 200 to 3,000 parts by mass, more preferably 250 to 2,000 parts by mass, and even more preferably 300 to 1,500 parts by mass. When the content is equal to or greater than the lower limit, the thermal conductivity of the cured product of the curable composition can be improved, and when the content is equal to or less than the upper limit, the moldability can be improved.

[0046] (Urethanization Catalyst) The curable composition according to this embodiment may or may not further contain a urethanization catalyst. However, from the viewpoint of promoting urethanization of the curable composition, it is preferable to contain a urethanization catalyst. The urethanization catalyst may be used alone or in combination of two or more. Examples of urethanization catalysts include amine catalysts [such as triethylenediamine, N-ethylmorpholine, diethylethanolamine, and 1,8-diazabicyclo(5.4.0)undecene-7] and metal catalysts [such as bismuth tris(2-ethylhexanoate), stannous octoate, dibutyltin dilaurate, and lead octoate]. These catalysts are also commercially available as inorganic bismuth catalysts [such as Neostan U-600, manufactured by Nitto Kasei Co., Ltd.]. The content of the urethanization catalyst is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of polyol.

[0047] (Dispersant) The curable composition according to this embodiment may or may not further contain a dispersant, but preferably contains a dispersant from the viewpoint of stably dispersing the filler during blending even during storage. Examples of dispersants include at least one selected from the group consisting of phosphate esters represented by the following general formula (1), fatty acids having 12 to 24 carbon atoms, sucrose fatty acid esters, sorbitan fatty acid esters, and glycerin fatty acid esters. Only one dispersant may be used, or two or more dispersants may be used in combination.

[0048] [In general formula (1), R １ is a hydrogen atom, an alkyl group having 2 to 18 carbon atoms, or an alkenyl group having 2 to 18 carbon atoms; A １ O is an oxyalkylene group having 2 to 3 carbon atoms, n1 is an integer from 3 to 15, and R ２ is a hydrogen atom or -(A ２ O) ｎ２ R ３ (R ３ is an alkyl group having 2 to 18 carbon atoms or an alkenyl group having 2 to 18 carbon atoms, and A ２ O is an oxyalkylene group having 2 to 3 carbon atoms, and n2 is an integer from 3 to 15.

[0049] Regarding the phosphate ester, in the general formula (1), R １ is a hydrogen atom, an alkyl group having 2 to 18 carbon atoms, or an alkenyl group having 2 to 18 carbon atoms.

[0050] Examples of the alkyl group having 2 to 18 carbon atoms include an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, and an octadecyl group, each of which may be linear or branched.

[0051] Examples of alkenyl groups having 2 to 18 carbon atoms include ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, and octadecenyl groups, each of which may be linear or branched, and the position of the double bond is not limited.

[0052] R １ The alkyl group may be linear or branched, but is preferably linear. From the viewpoints of the mechanical strength of the cured product of the curable composition and the dispersibility of the inorganic filler, the alkyl group is preferably an alkyl group having 12 to 18 carbon atoms.

[0053] In general formula (1), A １ O represents an oxyalkylene group having 2 to 3 carbon atoms, such as an ethyleneoxy group or a propyleneoxy group. Of these, the ethyleneoxy group is preferred from the viewpoint of dispersibility. n1 is an integer of 3 to 15, and is preferably 3 to 13, more preferably 4 to 11, from the viewpoints of good dispersibility of the inorganic filler and good mechanical strength of the cured product.

[0054] R ２ is a hydrogen atom or -(A ２ O) ｎ２ R ３ (R ３is an alkyl group having 2 to 18 carbon atoms or an alkenyl group having 2 to 18 carbon atoms, and A ２ O is an oxyalkylene group having 2 to 3 carbon atoms, and n2 is an integer from 3 to 15. ３ As for R １ The same can be mentioned as above, and the preferred examples are also the same. ２ As O, A １ The same as those for O can be mentioned, and the preferred ones are also the same. ２ is a hydrogen atom, the compound of general formula (1) is a monoester, and R ２ But-(A ２ O) ｎ２ R ３ In this case, the compound of general formula (1) is a diester. ２ But-(A ２ O) ｎ２ R ３ In the case of １ and R ３ may be the same or different. n1 and n2 may be the same or different.

[0055] As the phosphate ester represented by the general formula (1), R １ Two or more different types may be mixed and used, or a monoester (R ２ H) and diester (R ２ But-(A ２ O) ｎ２ R ３ A mixture of monoesters and diesters (mono-di mixture) may also be used. The phosphate ester represented by general formula (1) is generally obtained as a mixture of monoesters and diesters (mono-di mixture). Salts of the phosphate ester represented by general formula (1) (metal salts such as sodium, potassium, and magnesium, ammonium salts, etc.) may also be used.

[0056] Preferred examples of the phosphate ester represented by general formula (1) include alkyl ether phosphate esters and alkyl phosphate esters, with alkyl ether phosphate esters being more preferred. The phosphate ester represented by general formula (1) can be obtained by phosphate esterification using polyether and phosphorus oxide, and is commercially available as Disparlon DA-375 (manufactured by Kusumoto Chemical Co., Ltd.), Plysurf A208N (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Phosphanol RL-210 (manufactured by Toho Chemical Industry Co., Ltd., R1, R3: C18H37, mono- and di-mixture, n1, n2: 2), and Phosphanol RS-710 (manufactured by Toho Chemical Industry Co., Ltd., R １ , R ３ = C12-15 alkyl group, mono-di-mixture, n1, n2:9], Phosphanol RS-410 [manufactured by Toho Chemical Industry Co., Ltd., R １ , R ３ : C12-15 alkyl group, mono-di-mixture, n1,n2:3], etc.

[0057] Examples of fatty acids having 12 to 24 carbon atoms include saturated fatty acids having 12 to 24 carbon atoms (dodecanoic acid, hexadecanoic acid, eicosanoic acid, tetracosanoic acid, etc.) and unsaturated fatty acids having 12 to 24 carbon atoms (hexadecenoic acid, octadecenoic acid, octadecanedienoic acid, etc.), with hexadecenoic acid (oleic acid) being preferred.

[0058] Examples of sucrose fatty acid esters include esters of sucrose and fatty acids having 8 to 22 carbon atoms, and specific examples thereof include sucrose stearates [DK Ester F-50 (HLB=6), F-70 (HLB=8), and F-110 (HLB=11), all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., and Ryoto Sugar Ester S-770 (HLB=about 7), S-970 (HLB=about 9), S-1170 (HLB=about 11), and S-1170F (HLB=about 11), all manufactured by Mitsubishi Chemical Corporation].

[0059] Examples of sorbitan fatty acid esters include mono- to tri-esters of sorbitan with fatty acids having 8 to 22 carbon atoms, and specific examples thereof include sorbitan palmitate [e.g., Rheodol SP-P10 (HLB=6.7) manufactured by Kao Corporation, and Rikemal P-300 (HLB=5.6) manufactured by Riken Vitamin Co., Ltd.], sorbitan oleic acid monoester, fatty acid sorbitan ester [e.g., Ionet S-80 manufactured by Sanyo Chemical Industries, Ltd.], and polyoxyethylene sorbitan fatty acid ester [e.g., Ionet T-60V manufactured by Sanyo Chemical Industries, Ltd.].

[0060] Examples of glycerin fatty acid esters include mono- to tri-esters of glycerin or polyglycerin polymers (degree of polymerization 2 to 20) and fatty acids having 8 to 22 carbon atoms. Specific examples include diglycerin monolaurate [Poem DL-100 (HLB=9.4) manufactured by Riken Vitamin Co., Ltd., etc.], diglycerin monomyristate [Poem DM-100 (HLB=8.7) manufactured by Riken Vitamin Co., Ltd., etc.], diglycerin monolaurate ... Examples of such glycerol stearate include Poem DS-100A (HLB=7.7) manufactured by Riken Vitamin Co., Ltd., diglycerol monooleate (Poem DO-100V (HLB=7.3), Rikemal DO-100 (HLB=7.4) manufactured by Riken Vitamin Co., Ltd., etc.), and decaglycerol stearate (Poem J-0081HV (HLB=12), Poem J-0381V (HLB=12) manufactured by Riken Vitamin Co., Ltd., etc.).

[0061] Among sucrose fatty acid esters, sorbitan fatty acid esters, and glycerin fatty acid esters, sorbitan fatty acid esters are preferred, and sorbitan oleic acid monoester is more preferred.

[0062] The proportion by total weight of the phosphate ester and the fatty acid having 12 to 24 carbon atoms in 100% by mass of the curable composition is preferably 1 to 5% by mass, more preferably 1 to 3.5% by mass, and even more preferably 1 to 2% by mass, from the viewpoints of dispersibility of the inorganic filler and moldability.

[0063] The total weight ratio of the sucrose fatty acid ester, sorbitan fatty acid ester, and glycerin fatty acid ester in 100% by mass of the curable composition is preferably 1 to 5% by mass, more preferably 1 to 3% by mass, and even more preferably 1 to 2% by mass, from the viewpoints of dispersibility of the inorganic filler and moldability.

[0064] From the viewpoint of dispersibility of the inorganic filler, the dispersant preferably contains at least one selected from the group consisting of phosphate esters and fatty acids having 12 to 24 carbon atoms, and at least one selected from the group consisting of sucrose fatty acid esters, sorbitan fatty acid esters, and glycerin fatty acid esters.

[0065] The total weight of the dispersants relative to 100 parts by mass of the inorganic filler is preferably 1 to 15 parts by mass, more preferably 1 to 5 parts by mass, even more preferably 1 to 3 parts by mass, and still more preferably 1 to 2 parts by mass. When the total weight of the dispersants relative to 100 parts by mass of the inorganic filler is 1 to 15 parts by mass, the dispersibility of the inorganic filler is excellent and the moldability is also excellent.

[0066] (Surfactant) The curable composition according to the present embodiment may or may not further contain a surfactant, but preferably contains a surfactant from the viewpoint of stably dispersing the filler during storage. Only one surfactant may be used, or two or more surfactants may be used in combination. As the surfactant, polyoxyalkylene-type nonionic surfactants, ester-type nonionic surfactants, anionic surfactants, and cationic surfactants can be preferably used.

[0067] Examples of polyoxyalkylene type nonionic surfactants include AO adducts (preferably 1 to 30 moles added) of aliphatic alcohols (having 4 to 30 carbon atoms), alkyl (having 1 to 30 carbon atoms) phenols, aliphatic (having 4 to 30 carbon atoms) amines or aliphatic (having 4 to 30 carbon atoms) amides. Preferred aliphatic alcohols constituting polyoxyalkylene type nonionic surfactants include n-, i-, sec- or t-butanol, octanol, and dodecanol. Preferred alkylphenols include phenol, methylphenol, and nonylphenol. Preferred aliphatic amines include laurylamine and methylstearylamine. Preferred aliphatic amides include stearic acid amide.

[0068] Examples of the ester-type nonionic surfactant include ester compounds of fatty acids having 4 to 30 carbon atoms (such as lauric acid, stearic acid, and oleic acid) with polyhydric alcohols other than sucrose, sorbitol, and glycerin.

[0069] Examples of anionic surfactants include carboxylate, sulfate, and sulfonate types. Examples of carboxylate types include alkali metal salts of the above-mentioned fatty acids having 4 to 30 carbon atoms and alkali metal salts of polyoxyalkylene alkyl ether carboxylic acids. Examples of sulfate types include alkali metal sulfate esters of the above-mentioned aliphatic alcohols having 4 to 30 carbon atoms or AO adducts of aliphatic alcohols. Examples of sulfonate types include alkali metal sulfonates of alkylphenols. These surfactants are also commercially available as polyether carboxylic acids (Kao Akipo RLM-100, manufactured by Kao Corporation).

[0070] Examples of cationic surfactants include primary to tertiary amine salt types and quaternary ammonium salt types. Examples of primary to tertiary amine salt types include hydrochlorides of aliphatic amines having 4 to 30 carbon atoms [primary (such as laurylamine), secondary (such as dibutylamine), and tertiary amines (such as dimethylstearylamine)], and inorganic acid (such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid) salts of triethanolamine and monoesters of fatty acids having 4 to 30 carbon atoms. Examples of quaternary ammonium salt types include inorganic acid salts of quaternary ammonium having 4 to 30 carbon atoms (such as butyltrimethylammonium, diethyllaurylmethylammonium, and dimethyldistearylammonium). These surfactants are commercially available as Nopcosperse 092 [manufactured by San Nopco Ltd., cationic surfactant], etc.

[0071] The content of the surfactant in 100% by mass of the curable composition is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass, and even more preferably 0.1 to 2% by mass.

[0072] (Plasticizer) The curable composition according to the present embodiment may or may not further contain a plasticizer. However, it is preferable to contain a plasticizer from the viewpoint of reducing the viscosity when mixed with an inorganic filler and improving the mixability of the first and second parts. Only one type of plasticizer may be used, or two or more types may be used in combination. Examples of the plasticizer include phthalic acid plasticizers [diisononyl phthalate, di-(2-ethylhexyl) phthalate, diisodecyl phthalate, butyl benzyl phthalate, etc.], fatty acid ester plasticizers [di-(2-ethylhexyl) adipate, di-n-decyl adipate, di-(2-ethylhexyl) azelate, dibutyl sebacate, di-(2-ethylhexyl) sebacate, polyethylene glycol bis-2-ethylhexanoate, etc.], phosphate ester plasticizers [tributyl phosphate, tris(β-chloropropyl) phosphate, tri-(2-ethylhexyl)phosphate, 2-ethylhexyl diphenyl phosphate, etc.], benzoic acid-based plasticizers [polyethylene glycol benzoate esters], epoxy-based plasticizers such as epoxidized soybean oil, trimellitate-based plasticizers, pyromellitate-based plasticizers, polyester-based plasticizers, sulfonate-based plasticizers, etc. Also available on the market are diisononyl phthalate [manufactured by Aekyung Petrochemical, DINP], polyethylene glycol benzoate [manufactured by Sanyo Chemical Industries, Ltd., EB-300], etc.

[0073] The content of the plasticizer in 100% by mass of the curable composition is preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass, and even more preferably 1 to 5% by mass.

[0074] (Other Components) The curable composition according to the present embodiment may contain antioxidants, ultraviolet absorbers, colorants, silane coupling agents, and other components to the extent that they do not inhibit the curing of the present invention. Examples of antioxidants include hindered phenol compounds. Examples of hindered phenol compounds include 4-[[4,6-bis(octylthio)-1,3,5-triazin-2-yl]amino]-2,6-di-tert-butylphenol, 2,2'-thiodiethylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and [triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], and examples of such compounds include Irganox 565 (manufactured by BASF Japan Ltd.) and Irganox 1135 (manufactured by BASF Japan Ltd.). Examples of ultraviolet absorbers include benzotriazoles, benzophenones, salicylates, and acrylates. Examples of colorants include organic pigments, such as phthalocyanine blue, insoluble azo pigments, soluble azo pigments, and condensed azo pigments, and examples of such pigments include ZA Blue #2200 (manufactured by Mikuni Color Co., Ltd.). Examples of silane coupling agents include diphenyldimethoxysilane, decyltrimethoxysilane, phenyltrimethoxysilane, propyltrimethoxysilane, and hexyltrimethoxysilane. Product names include KBM-202SS (diphenyldimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.), KBM-3103C (decyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.), KBM-103 (phenyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.), KBM-3033 (propyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.), and KBM-3063 (hexyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.). The curable composition according to the present embodiment may or may not contain a compound having a structure derived from an aromatic polycarboxylic acid having three or more carboxy groups or an anhydride thereof. When such a compound is contained, the content of the compound in 100% by mass of the curable composition is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less.The polyol and polyisocyanate do not have a structure derived from an aromatic polycarboxylic acid having three or more carboxy groups or an anhydride thereof. The total amount of the polyol, polyisocyanate, inorganic filler, urethanization catalyst, dispersant, surfactant, and plasticizer in 100% by mass of the curable composition is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be 100% by mass.

[0075] (Form of curable composition) The curable composition according to this embodiment may be either a one-component type or a two-component type, but a two-component type is preferred from the viewpoint of keeping the viscosity low and ensuring sufficient contact of the curable composition with the surface to be coated. In the case of a two-component type, it is preferable that the composition comprises a first component containing a polyol and a second component containing a polyisocyanate. Note that even in the case of a two-component type curable composition, the preferred types and contents of each component are as described above.

[0076] The inorganic filler may be contained in either the first agent or the second agent, or may be contained in both the first agent and the second agent, but from the viewpoint of favorable mixing of the first agent and the second agent, it is preferable to contain the inorganic filler in both the first agent and the second agent. The content of the inorganic filler contained in the first agent is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, even more preferably 40 to 60% by mass, and still more preferably 45 to 55% by mass, relative to 100% by mass of the total amount of the inorganic fillers contained in the first agent and the second agent.

[0077] The urethanization catalyst is contained only in the first agent. The dispersant may be contained in either the first agent or the second agent, or in both the first agent and the second agent, but is preferably contained in the first agent from the viewpoint of storage stability. The surfactant may be contained in either the first agent or the second agent, or in both the first agent and the second agent, but is preferably contained in the first agent from the viewpoint of storage stability. The plasticizer may be contained in either the first agent or the second agent, or in both the first agent and the second agent, but is preferably contained in the second agent from the viewpoint of viscosity reduction.

[0078] The content of the second agent relative to 100 parts by mass of the first agent is preferably 50 to 120 parts by mass, more preferably 60 to 120 parts by mass, even more preferably 80 to 110 parts by mass, and still more preferably 90 to 110 parts by mass, from the viewpoint of mixing the two agents well.

[0079] (Method for Producing Curable Composition) The curable composition can be suitably produced by mixing the above-mentioned components in the first and second parts as described above.

[0080] [Heat Dissipating Member] The heat dissipating member according to the present embodiment includes a cured product of the curable composition according to the present embodiment. The heat dissipating member is suitable for use in heat-generating parts (inverters, chargers) of electric vehicles such as lithium-ion batteries, semiconductor elements, relays, switching circuits, etc.

[0081] The present invention will be specifically described below based on examples. However, the present invention is not limited to the examples described below, and various modifications are possible as long as they do not change the gist of the present invention. Among Examples 1 to 21, Examples 1 to 16 are Examples, and Examples 17 to 21 are Comparative Examples.

[0082] [Measurement Methods] The methods for measuring various properties of each raw material and component are as follows.

[0083] (Number average molecular weight (Mn)) Mn was measured in terms of polystyrene by gel permeation chromatography (GPC) under the following conditions, and calculated from these values. [Measurement conditions] - Instrument used: "HLC-8320GPC", manufactured by Tosoh Corporation - Column used: "TSKgel (registered trademark) SuperMultiporeHZ-M", manufactured by Tosoh Corporation - Detector: Refractive index (RI) detector - Detection temperature: 40°C - Eluent: Tetrahydrofuran - Flow rate: 0.350 mL / min - Sample concentration: 0.5% by mass - Sample injection amount: 10 μL - Standard sample: Polystyrene

[0084] (Hydroxyl Value) The hydroxyl value was determined in accordance with Method B (automatic potentiometric titration) of JIS K 1557-1:2007.

[0085] (Ethylene oxide (EO) unit content and propylene oxide (PO) unit content) The amount of EO charged and the amount of PO charged, relative to the total amount (100 mass %) of raw materials charged in the synthesis of a polyol, were considered to be the EO unit content and the PO unit content in the polyol, respectively.

[0086] Synthesis Example 1 (Polyol A1-1) A pressure-resistant vessel was charged with 1,000 g of propylene glycol as an initiator and potassium hydroxide as a catalyst. The atmosphere inside the vessel was replaced with nitrogen, and the reaction solution was heated to 120°C while stirring. 1,050 g of PO and 6,149 g of EO were added to the vessel. After confirming that the internal pressure had stopped changing, an adsorbent was added, neutralization was carried out, and the catalyst was removed, yielding a polyether polyol (number average molecular weight 1,100, EO units 75 mass%, PO units 12.8 mass%, initiator units 12.2 mass%, functionality 2, hydroxyl value 102 mgKOH / g).

[0087] Synthesis Example 2 (Polyol A1-2) Into a pressure-resistant vessel, 1,000 g of polypropylene glycol obtained by adding 15.7 moles of PO to glycerin as an initiator and potassium hydroxide as a catalyst were placed. The atmosphere inside the vessel was then replaced with nitrogen, and the reaction solution was heated to 120°C while stirring. 3,522 g of PO was added and reacted, and then the reaction solution was cooled to 120°C. 475 g of EO was added to the vessel while stirring. After confirming that the internal pressure had stopped changing, an adsorbent was added, followed by neutralization and catalyst removal, to obtain a polyether polyol (number average molecular weight 5,000, EO units 9.5 mass%, PO units 88.7 mass%, initiator units 1.8 mass%, functionality 3, hydroxyl value 34 mgKOH / g).

[0088] Synthesis Example 3 (Polyol A1-3) A pressure-resistant vessel was charged with 1,000 g of polypropylene glycol obtained by adding 5.6 moles of PO to propylene glycol as an initiator, and potassium hydroxide as a catalyst. The atmosphere inside the vessel was then replaced with nitrogen, and the reaction solution was heated to 105°C while stirring. 5,250 g of PO was added and reacted, and after confirming that there was no longer any change in the internal pressure, an adsorbent was added, neutralization was carried out, and the catalyst was removed, yielding a polyether polyol (number average molecular weight 2,000, 100 mass% of PO units, 3.8 mass% of initiator units, number of functional groups 2, hydroxyl value 56 mgKOH / g). Synthesis Example 4 (Polyol A2-1) A pressure-resistant vessel was charged with 1,000 g of 2-aminoethanol as an initiator and potassium hydroxide as a catalyst. The atmosphere inside the vessel was replaced with nitrogen, and the reaction solution was heated to 120°C while stirring. 4,512 g of PO was added and reacted. After confirming that there was no longer any change in the internal pressure, an adsorbent was added, followed by neutralization and removal of the catalyst, yielding an amine polyol (number average molecular weight 337, EO units 0 mass %, PO units 100 mass %, number of hydroxyl groups 2, hydroxyl value 500 mgKOH / g).

[0089] [Raw Materials for Curable Composition] The following raw materials were used for the curable composition. (Polyether polyol (A1)) (1) Polyol A1-1: Polyether polyol obtained in Synthesis Example 1. (2) Polyol A1-2: Polyether polyol obtained in Synthesis Example 2. (3) Polyol A1-3: Polyether polyol obtained in Synthesis Example 3. (Amine polyol (A2)) (1) Polyol A2-1: Amine polyol obtained in Synthesis Example 4. (2) Polyol A2-2: Polyether polyol obtained by adding 9.2 moles of PO using 2,4-diaminotoluene as an initiator. (Aliphatic polyhydric alcohol (A3) having Mn of less than 1,100) (1) Polyol A3-1: Propane-1,2-diol (propylene glycol). (Other Polyols (A4)) (1) Polyol A4-1: Polyether polyol of anionic ring-opening polymerization product of polyethylene glycol, ethylene oxide, and water, hydroxyl value 280.6 mg KOH / g, number average molecular weight 400. (2) Polyol A4-2: Aliphatic polyester diol obtained by reaction of 3-methyl-1,5-pentanediol and adipic acid, number average molecular weight 2,000, functionality 2, hydroxyl value 56.1 mg KOH / g, manufactured by Kuraray Co., Ltd.: Kuraray Polyol P-2010. (3) Polyol A4-3: Polycarbonate diol, number average molecular weight 500, hydroxyl value 224.4 mg KOH / g, manufactured by Kuraray Co., Ltd.: Kuraray Polyol C-590. (4) Polyol A4-4: Castor oil-based polyol primarily composed of ricinoleic acid, hydroxyl value 160 mg KOH / g, number average molecular weight 950, manufactured by Ito Oil Mills: URIC H-30. (5) Polyol A4-5: Polytetramethylene ether glycol, number average molecular weight 1000, manufactured by Mitsubishi Chemical Corporation: PTMG1000. (6) Polyol A4-6: Polyether polyol using pentaerythritol as an initiator and 7.1 moles of PO added, number average molecular weight 550. (7) Polyol A4-7: Polyether polyol using a mixture of sucrose and glycerin in an 88%:12% by weight mixture as an initiator and 9.0 moles of PO added, number average molecular weight 520. (8) Polyol A4-8: Polyether polyol using glycerin as an initiator and 5.3 moles of PO added, number average molecular weight 420.(9) Polyol A4-9: A polyether polyol prepared by adding 12.0 moles of PO to sorbitol as an initiator, having a number average molecular weight of 875. (10) Polyol A4-10: A polyether polyol prepared by adding 8.4 moles of PO to sorbitol as an initiator, having a number average molecular weight of 673.

[0090] (Polyisocyanates) (1) Polyisocyanate B1: polymeric MDI (polymethylene polyphenyl polyisocyanate), NCO content 31.0 mass%, manufactured by Tosoh Corporation: MR-200 (2) Polyisocyanate B2: low-viscosity polymeric MDI (polymethylene polyphenyl polyisocyanate), NCO content 32.4 mass%, manufactured by Tosoh Corporation: Coronate 1331 (3) Polyisocyanate B3: XDI (m-xylylene diisocyanate), NCO content 44.6 mass%, manufactured by Mitsui Chemicals, Inc.: Takenate 500. (4) Polyisocyanate B4: IPDI (isophorone diisocyanate), NCO content 37.8 mass%, manufactured by Covestro: Dismodur I. (5) Polyisocyanate B5: hexamethylene diisocyanate trimer, NCO content 23.2% by mass, manufactured by Asahi Kasei Corporation: Duranate TLA-100. (6) Polyisocyanate B6: 4,4'-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, a mixture of trimethyl phosphate modified with polyol, NCO content 23.1% by mass, manufactured by Tosoh Corporation: Coronate 1050. (7) Polyisocyanate B7: xylylene diisocyanate modified with trimethylolpropane, NCO content: 11.5% by mass, solids concentration: 75% by mass, solvent: ethyl acetate, viscosity (25°C): 500 mPa s, manufactured by Mitsui Chemicals, Inc.: Takenate D-110N.

[0091] (Inorganic fillers) (1) Inorganic filler C1: Spherical alumina having an average particle size (D50) of 75 μm, obtained by heating and melting crushed alumina powder in the atmosphere (thermal spraying method) to form spheres, manufactured by Nippon Steel Chemical & Material Co., Ltd.: Alumina spherical fine particles AZ75-150. (2) Inorganic filler C2: Spherical alumina having an average particle size (D50) of 4.5 μm, obtained by heating and melting crushed alumina powder in the atmosphere (thermal spraying method) to form spheres, manufactured by Nippon Steel Chemical & Material Co., Ltd.: Alumina spherical fine particles AZ4-75. (3) Inorganic filler C3: A method for producing spherical oxide particles utilizing the deflagration phenomenon of metal powder, in which metal powder is dispersed in an oxygen stream, ignited to oxidize, the metal and oxide are vaporized or liquidized by the heat of reaction, and then cooled to obtain fine oxide particles. Spherical alumina with an average particle size (D50) of 0.3 μm, manufactured by Admatechs: ADMAFINE AO-502. (4) Inorganic filler C4: A method for producing spherical oxide particles utilizing the deflagration phenomenon of metal powder, in which metal powder is dispersed in an oxygen stream, ignited to oxidize, the metal and oxide are vaporized or liquidized by the heat of reaction, and then cooled to obtain fine oxide particles. Spherical alumina with an average particle size (D50) of 10 μm, manufactured by Admatechs: ADMAFINE AO-509. (5) Inorganic filler C5: Alumina crushed powder is melted at high temperature in the atmosphere (thermal spraying) to form spherical alumina having an average particle size (D50) of 6.4 μm, manufactured by Denka Co., Ltd.: Spherical Alumina DAW-05. (6) Inorganic filler C6: Alumina crushed powder is melted at high temperature in the atmosphere (thermal spraying) to form spherical alumina having an average particle size (D50) of 97.4 μm, manufactured by Denka Co., Ltd.: Spherical Alumina DAW-90. (7) Inorganic filler C7: A zinc oxide solution is neutralized with an alkaline aqueous solution, and then crystallized in the presence of a hydrophilic dispersant to form spherical zinc oxide having an average particle size (D50) of 70 μm, manufactured by Sakai Chemical Industry Co., Ltd.: LPZINC-50S. (8) Inorganic filler C8: Aluminum hydroxide filler ("SBX73" manufactured by Nippon Light Metal Co., Ltd., spherical, with an average particle size (D50) of 61 μm). (9) Inorganic filler C9: Aluminum hydroxide filler ("BX053" manufactured by Nippon Light Metal Co., Ltd., spherical, with an average particle size (D50) of 6 μm).(10) Inorganic filler C10: Magnesium oxide filler, spherical, phenyl-based surface-treated with an average particle size of 40 to 70 μm ("RF-50-FC" manufactured by Ube Material Industries, Ltd.) (11) Inorganic filler C11: Magnesium oxide filler, spherical, phenyl-based surface-treated with an average particle size of 70 to 120 μm ("RFA-100-FC" manufactured by Ube Material Industries, Ltd.)

[0092] (Urethanization catalyst) (1) Urethane catalyst D1: bismuth tris(2-ethylhexanoate), Bi content 18.0 to 19.0 mass %, manufactured by Nitto Kasei Co., Ltd.: Neostan U-600.

[0093] (Dispersant) (1) Dispersant E1: Polyoxyethylene alkyl ether phosphate ester (R １ , R ３ : C12-C15 alkyl group, 9 moles of EO added). Toho Chemical Industry Co., Ltd.: Phosphanol RS-710. １ , R ３ The description "C12 to C15 alkyl group, 9 moles of EO added" refers to R in general formula (1). １ is an alkyl group having 12 to 15 carbon atoms, R ３ is an alkyl group having 12 to 15 carbon atoms; A １ and A ２ means an oxyalkylene group having 2 carbon atoms (oxyethylene group (EO)), and n1 and n2 are 9. (2) Dispersant E2: Polyoxyethylene sorbitan fatty acid ester, manufactured by Kao Corporation: Rheodol TW-S120V.

[0094] (Surfactants) (1) Surfactant F1: Polyoxyethylene lauryl ether sodium acetate, manufactured by Kao Corporation: Kao Akipo RLM-100.

[0095] (Plasticizers) (1) Plasticizer G1: polyethylene glycol benzoate ester, manufactured by Sanyo Chemical Industries, Ltd.: Sunflex EB-300 (2) Plasticizer G2: DINP (diisononyl phthalate), manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. (3) Plasticizer G3: TCPP [tris(β-chloropropyl)phosphate], manufactured by Daihachi Chemical Industries, Ltd.: TMCPP. (4) Plasticizer G4: TBP (tributyl phosphate), manufactured by Daihachi Chemical Industry Co., Ltd.: TBP (5) Plasticizer G5: polyethylene glycol bis(2-ethylhexanoate), manufactured by DIC Corporation: Monocizer W-260 (6) Plasticizer G6: benzoate ester-based plasticizer mixed with diisononyl adipate, manufactured by DIC Corporation: Monocizer PB-3A (7) Plasticizer G7: benzoate ester-based plasticizer, manufactured by DIC Corporation: Monocizer PB-10 (Colorant) (1) ZA Blue #2200, manufactured by Mikuni Pigment Co., Ltd.: blue pigment dispersed in polyol A1-3 (Antioxidant) (1) 4-[[4,6-bis(octylthio)-1,3,5-triazin-2-yl]amino]-2,6-di-tert-butylphenol, manufactured by BASF Japan Ltd.: Irganox 565 (silane coupling agent) (1) Diphenyldimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.: KBM-202SS The raw materials of the curable composition are summarized in Table 1 below.

[0096]

[0097] Preparation Examples 1 to 21 (Preparation of First Agents) The components shown in Tables 2 and 3 were mixed in the blending ratios shown in Tables 2 and 3 using a planetary mixer (Device name: T.K.HIVIS MIX Model 2P-03, manufactured by Primix Corporation) to prepare first agents.

[0098] Preparation Examples 22 to 42 (Preparation of Second Agents) The components shown in Tables 2 and 3 were mixed in the blending ratios shown in Tables 2 and 3 using a planetary mixer (Device name: T.K.HIVIS MIX Model 2P-03, manufactured by Primix Corporation) to prepare second agents.

[0099] [Example 1] (Production of curable composition 1) A two-component curable composition 1 was obtained by preparing the first component of Preparative Example 1 and the second component of Preparative Example 22 so that the ratio of the second component of Preparative Example 22 to 100 parts by mass of the first component of Preparative Example 1 was the value (100 parts by mass) shown in Table 2.

[0100] [Examples 2 to 21] (Production of Curable Compositions 2 to 21) Two-component curable compositions 2 to 21 were obtained by preparing the first and second components so that the ratio of the second component (Preparation Examples 23 to 42) to 100 parts by mass of the first component (Preparation Examples 2 to 21) was the value shown in Tables 2 and 3.

[0101] [Evaluation] (Curability after 2 hours) The first and second parts were mixed using a planetary mixer "Thinky Mixer AR-250" so that the ratio of the second part (Preparation Examples 22 to 42) to 100 parts by mass of the first part (Preparation Examples 1 to 21) was the value shown in Tables 2 and 3, to obtain Mixtures 1 to 21. Next, Mixtures 1 to 21 were poured into a molding die (20 cm long x 20 cm wide x 0.2 cm deep) so that the mixture filled the die, and the die was pressed by closing it. The mixtures were then allowed to stand at 25°C for 2 hours to react. The mixtures were then demolded to obtain sheet-shaped test pieces 1 to 21. The obtained test pieces and the molding die after demolding were observed and evaluated as follows: Uncured: A portion of the test piece remained in the molding die, or the test piece was not sufficiently cured. Cured: No test piece remained in the molding die, and the test piece was sufficiently cured. Granular: The fillers were bonded together and precipitated without being covered with resin.

[0102] (Thermal Conductivity) Mixtures 1 to 21 obtained in the same manner as in the "2-Hour Curing" section above were poured into a molding die (20 cm long x 20 cm wide x 0.2 cm deep) to fill it, and the die was closed to press. The mixture was then allowed to react at 25°C for 24 hours. The mixture was then demolded to obtain sheet-shaped heat dissipation members 1 to 21. The heat dissipation members 1 to 21 were cut into 1 cm long x 1 cm wide x 0.2 cm deep specimens 1A to 21A for measurement. The thermal conductivity (unit: W / m K) of the obtained specimens 1A to 21A was measured by the laser flash method using a thermal conductivity meter "Xenon Flash Analyzer LFA447 NanoFlash, manufactured by Netzsch Japan." The higher the thermal conductivity, the better the heat dissipation. A thermal conductivity of 1.0 W / m K or higher indicates excellent heat dissipation. In Example 20, the heat dissipation member 20 crumbled when it was cut into a size of 1 cm length × 1 cm width × 0.2 cm depth, making it impossible to obtain a sample for measurement. Therefore, in Table 3, this is shown as "unmoldable."

[0103] (Tensile Breaking Elongation) Heat dissipating members 1 to 21 obtained in the same manner as in the above "Thermal Conductivity" were punched out with a No. 1 dumbbell as described in JIS K7312:1996, and the elongation at break was measured as the tensile breaking elongation (%) in accordance with JIS K7312:1996 using a "Tensilon RTF-1310 Tester manufactured by A&D Co., Ltd." A tensile breaking elongation of 2.0% or more indicates excellent extensibility. In Example 20, heat dissipating member 20 collapsed when punched out with the No. 1 dumbbell, and a dumbbell-shaped sample could not be obtained. Therefore, in Table 3, it is shown as "unmoldable."

[0104]

[0105]

[0106] The curable compositions according to the Examples were cured after 2 hours of curing, demonstrating excellent curability. Furthermore, the curable compositions according to the Examples were able to give cured products with high thermal conductivity and high elongation at break. On the other hand, the curable compositions according to Examples 17, 18, and 21 did not cure after 2 hours of curing. Furthermore, the curable compositions according to Examples 17 to 19 and 21 were inferior to the Examples in at least one of thermal conductivity and elongation at break. Furthermore, the curable composition according to Example 20 was granular after 2 hours of curing, and could not be molded.

Claims

1. A curable composition comprising a polyol, a polyisocyanate, and an inorganic filler, wherein the polyol comprises a polyether polyol containing one or more groups selected from the group consisting of an oxyethylene group and an oxypropylene group and having a number average molecular weight of 1,100 or more, the content of the polyether polyol in 100% by mass of the polyol is 55% by mass or more, and the content of the inorganic filler in 100% by mass of the curable composition is 50 to 90% by mass.

2. The curable composition according to claim 1, wherein the proportion of the oxyethylene groups is 0% by mass to 95% by mass in 100% by mass of the total amount of the polyether polyol.

3. The curable composition according to claim 1 or 2, wherein the polyisocyanate is at least one selected from the group consisting of aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates.

4. The curable composition according to claim 1 or 2, further comprising a urethanization catalyst.

5. The curable composition according to claim 1 or 2, wherein the polyol further comprises an amine polyol obtained by polymerizing an alkylene oxide with an initiator having an amino group.

6. The curable composition according to claim 5, wherein the content of said amine polyol is 3 to 40 mass % in 100 mass % of said polyol.

7. The curable composition according to claim 1 or 2, wherein the inorganic filler is a metal, a metal oxide, a metal nitride, a metal hydroxide or a metal carbonate.

8. The curable composition according to claim 1 or 2, which is for use in a heat dissipating member.

9. The curable composition according to claim 5, which is for use in a heat dissipating member.

10. A heat dissipating member comprising a cured product of the curable composition according to claim 1 or 2.

Images