Curable composition and heat-dissipating member

Abstract

Provided is a curable composition comprising a polyol, a polyisocyanate, an inorganic filler, and a dehydrating agent, wherein: the polyol contains a polyether polyol that contains at least one group selected from the group consisting of oxyethylene groups and oxypropylene groups and that has 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; the content of the inorganic filler in 100 mass% of the curable composition is 50-90 mass%; and the content of the dehydrating agent in 100 mass% of the curable composition is 0.05-5 mass%.

Description

Curable composition and heat dissipation member

[0001] The present invention relates to a curable composition and a heat-dissipating member, and more particularly to a curable composition that yields a cured product with excellent thermal conductivity, elongation at break, and adhesion even when cured in a high-humidity environment, and a heat-dissipating member containing the cured product.

[0002] As materials for dissipating heat generated by heat-generating elements such as semiconductor devices and lithium-ion batteries to the outside of the heat-generating element, silicone compositions containing silicone and inorganic fillers, acrylic compositions containing acrylic resin and inorganic fillers, and urethane compositions containing urethane raw materials and inorganic fillers are known. Among these, silicone compositions have the problem of poor conductivity due to low molecular weight siloxanes in the composition. Acrylic compositions have the problem that their high hardness prevents them from following the irregularities of the coated surface, which can result in insufficient heat dissipation. In contrast, urethane compositions have low hardness and can follow the irregularities of the coated surface, making them a material with excellent heat dissipation properties as heat conduction from the heat-generating element is facilitated. Patent Document 1 discloses a curable composition containing a polyol, a polyisocyanate, a dispersant for inorganic fillers, and an inorganic filler, wherein the polyol contains 50% by mass or more of polyalkylene glycol having a chemical formula weight or number average molecular weight of 1,000 or less, based on the mass of the polyol. Patent Document 2 discloses a two-component urethane composition comprising: an ester-based polyol resin-containing main component composition; a polyisocyanate-containing curing agent composition; a filler; and a phosphate ester-based anionic dispersant, characterized in that the anionic dispersant is present in less than 20 parts by mass per 100 parts by mass of the total ester-based polyol resin and polyisocyanate combined.

[0003] International Publication No. 2021 / 261519, JP 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 elongation at break, nor has it been studied. Therefore, the present inventors investigated and found that the curable composition described in Patent Document 1 had insufficient elongation at break. Furthermore, it was confirmed that when the curable composition described in Patent Document 1 was cured in a high-humidity environment, its adhesiveness decreased. Patent Document 2 aims to provide a resin composition for battery modules with excellent heat dissipation, adhesive strength, cold resistance, heat resistance, insulation, and adhesive reliability, but does not address the issue of elongation at break, nor has it been studied. Therefore, the present inventors investigated and found that the curable composition described in Patent Document 2 had high hardness and insufficient elongation at break. Furthermore, it was confirmed that when the curable composition described in Patent Document 2 was cured in a high-humidity environment, its adhesiveness decreased. As with the compositions described in Patent Documents 1 and 2, if the elongation at break is insufficient or if the adhesiveness decreases when the curable composition is cured in a high-humidity environment, when the heating element moves due to vibration or the like, the composition does not follow the movement and therefore cannot maintain close contact, resulting in a decrease in thermal conductivity. The present invention has been made in view of these circumstances and aims to provide a curable composition that yields a cured product with excellent thermal conductivity, elongation at break, and adhesiveness even when cured in a high-humidity environment, and a heat-dissipating member containing the cured product.

[0005] As a result of diligent research, the inventors have found that a curable composition comprising a polyol, polyisocyanate, and a predetermined amount of inorganic filler and dehydrating agent, even when cured in a high-humidity environment, yields a cured product with excellent thermal conductivity, elongation at break, and adhesion. The present invention was completed based on these findings.

[0006] The present invention is as follows: [1] A curable composition comprising a polyol, a polyisocyanate, an inorganic filler, and a dehydrating agent, wherein the polyol contains one or more groups selected from the group consisting of oxyethylene groups and oxypropylene groups and has 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, the content of the inorganic filler in 100% by mass of the curable composition is 50 to 90% by mass, and the content of the dehydrating agent in 100% by mass of the curable composition is 0.05 to 5% by mass. [2] The curable composition according to [1], wherein the 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 selected from the group consisting of aliphatic polyisocyanate, alicyclic polyisocyanate, and aromatic polyisocyanate. [4] The curable composition according to any one of [1] to [3] above, wherein the polyisocyanate comprises at least one of aliphatic polyisocyanate and an isocyanurate of aliphatic polyisocyanate. [5] The curable composition according to any one of [1] to [4] above, wherein the polyisocyanate comprises at least one of hexamethylene diisocyanate and an isocyanurate of hexamethylene diisocyanate. [6] The curable composition according to any one of [1] to [5] above, wherein the curable composition further comprises a urethane catalyst. [7] The curable composition according to any one of [1] to [6] above, wherein the inorganic filler is one or more selected from the group consisting of metal, metal oxide, metal nitride, metal hydroxide, and metal carbonate. [8] The curable composition according to any one of [1] to [7] above, wherein the inorganic filler contains a metal hydroxide. [9] The curable composition according to any one of [1] to [8] above, wherein the inorganic filler contains aluminum hydroxide.

[10] The curable composition according to [7] or [8] above, wherein the oil absorption amount of the metal hydroxide is 40 mL / 100 g or less.

[11] The curable composition according to any one of [1] to

[10] above, wherein the dehydrating agent is one or more selected from the group consisting of calcium chloride, calcium oxide, calcium sulfate, silica gel, and molecular sieves.

[12] The curable composition according to any one of [1] to

[11] above, wherein the isocyanate index represented by the following formula is 40 to 57. Isocyanate index = [NCO number] / [OH number] × 100 NCO number: Total number of moles of isocyanate groups in polyisocyanate OH number: Total number of moles of hydroxyl groups in polyol

[13] The curable composition according to any one of [1] to

[12] above, comprising a first agent containing a polyol and a second agent containing a polyisocyanate.

[14] The curable composition according to any one of [1] to

[13] above, for use as a heat dissipation member.

[15] A heat dissipation member comprising a cured product of the curable composition according to any one of [1] to

[13] above.

[16] The heat dissipation member described in

[15] above, used in the heat-generating parts of an electric vehicle.

[0007] According to the present invention, it is possible to provide a curable composition that yields a cured product with excellent thermal conductivity, elongation at break, and adhesion even when cured in a high-humidity environment, and a heat-dissipating member containing the cured product.

[0008] The definitions and meanings of terms and notations used herein are given below. In this specification, preferred provisions can be adopted at will, and combinations of preferred provisions are considered more preferred. In this specification, the notation "XX to YY" means "XX or more and YY or less". In this specification, the lower and upper limits of preferred numerical ranges (e.g., ranges of content, etc.) described in steps can be combined independently. For example, from the notation "preferably 10 to 90, more preferably 30 to 60", the "preferred lower limit (10)" and the "more preferred upper limit (60)" can be combined to get "10 to 60". Also, in numerical ranges described herein, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. In this specification, "number-average molecular weight (Mn)" is the polystyrene-equivalent molecular weight determined by measurement using gel permeation chromatography (GPC) based on a calibration curve created using standard polystyrene samples. In this specification, "hydroxyl value" is a value obtained by measurement in accordance with Method B (potentiometric automatic titration) of JIS K 1557-1:2007. In this specification, "isocyanate index" means the following: Isocyanate index = [NCO number] / [OH number] × 100 NCO number: Total number of moles of isocyanate groups in polyisocyanate OH number: Total number of moles of hydroxyl groups in polyol In this specification, "ethylene oxide (EO) unit", "propylene oxide (PO) unit", and "alkylene oxide (AO) unit" mean units derived from EO, units derived from PO, and units derived from AO. Similarly, X unit means a unit derived from compound X. In this specification, "PO" means 1,2-PO unless otherwise specified. In this specification, "high humidity environment" means an environment with a humidity of 60% or higher. In this specification, "humidity" refers to the value obtained using the Expo Pocket Thermometer and Hygrometer (TH-220, manufactured by AS ONE Corporation).

[0009] [Curable Composition] The curable composition according to an embodiment of the present invention (hereinafter sometimes referred to as "this embodiment") is a curable composition comprising a polyol, a polyisocyanate, an inorganic filler, and a dehydrating agent, wherein the polyol contains one or more selected from the group consisting of oxyethylene groups and oxypropylene groups and has 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, the content of the inorganic filler in 100% by mass of the curable composition is 50 to 90% by mass, and the content of the dehydrating agent in 100% by mass of the curable composition is 0.05 to 5% by mass. The curable composition of this embodiment, having such a configuration, yields a cured product with excellent thermal conductivity, elongation at break, and adhesion even when cured in a high-humidity environment. The detailed mechanism for this is unknown, but it is presumed to be as follows. (1) Mechanism for excellent thermal conductivity and elongation at break Generally, resins have low thermal conductivity, so inorganic fillers are added to curable compositions to increase the thermal conductivity of the cured product. In the curable composition according to this embodiment, the flexibility of the resin is effective, increasing the number of contact points between the inorganic fillers and allowing sufficient heat transfer paths to be formed, thus resulting in high thermal conductivity. Furthermore, in order to improve the thermal conductivity of the cured product of the curable composition, it is desirable that the inorganic fillers penetrate firmly into the surface irregularities of the heat dissipation member. For this reason, the cured product of a curable composition containing inorganic fillers is required to be able to adhere closely to a heat-generating element such as a battery housing and a sheet sink, to have sufficient flexibility in the resin to follow vibrations, and to have high elongation at break. The polyol contains one or more groups selected from the group consisting of oxyethylene groups and oxypropylene groups, and has a number average molecular weight of 1,100 or more, and the content of the polyether polyol in 100% by mass of the polyol is 55% by mass or more, thereby exhibiting appropriate flexibility and crosslinkability, and a high elongation at break is obtained as a cured product. Note that the flexibility described in Patent Document 1 simply refers to the surface hardness of the composition after curing. On the other hand, the elongation at break of the present 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 flexibility and elongation at break do not necessarily correlate in the cured product of a curable composition. For example, if the cured product exhibits mechanical properties that make it prone to fracture or if it is highly brittle, the flexibility will be high (hardness will be low) but the elongation at break will be low. (2) Mechanism for excellent adhesion even when the curable composition is cured in a high humidity environment When the curable composition is cured, it is thought that the isocyanate present in the curable composition reacts with the water present in the curable composition (side reaction) to generate amine compounds and carbon dioxide. This carbon dioxide then causes bubbles to form in the cured product, making it difficult for the cured product to adhere closely to heat-generating elements such as battery housings, and as a result, the adhesion is thought to decrease. Furthermore, it is thought that the decrease in adhesion due to bubbles also causes a decrease in thermal conductivity. Based on the above, it is expected that when a curable composition containing isocyanate is cured in a high humidity environment, the above reaction (side reaction) is more likely to occur, and the adhesion of the cured product of the curable composition will decrease. The curable composition according to this embodiment contains a predetermined amount of a dehydrating agent, which removes water from the curable composition. As a result, the above-mentioned reaction (side reaction) is less likely to occur, and therefore, the curable composition is expected to exhibit excellent adhesion even when cured in a high-humidity environment.

[0010] (Polyol) The polyol contains a polyether polyol (A1), described later, as an essential component. The polyol may also contain, or may not contain, an amine polyol (A2), described later, an aliphatic polyhydric alcohol (A3) with a Mn of less than 1,100, described later, a polyether polyol (A4) with a Mn of less than 1,100, described later, a polycarbonate polyol (A5), described later, a castor oil-based polyol (A6), described later, or other polyols described later. These may be used individually or in combination of two or more. The polyol content 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, from the viewpoint of improving curability and obtaining a cured product with excellent thermal conductivity and elongation at break.

[0011] <Polyether Polyol (A1)> The above polyol contains a polyether polyol (A1) which contains one or more groups selected from the group consisting of oxyethylene groups and oxypropylene groups and has a number average molecular weight of 1,100 or more. Only one type of polyether polyol (A1) may be used, or two or more types may be used in combination. There are no particular restrictions on the proportion of oxyethylene groups in 100% by mass of the total amount of polyether polyol (A1), but it is preferably 0 to 95% by mass. This yields a cured product with excellent thermal conductivity and elongation at break. Furthermore, it is preferable that the polyether polyol (A1) contains oxypropylene groups. This yields a cured product suitable for heat dissipation materials. From this viewpoint, there are no particular restrictions on the proportion of oxyethylene groups in 100% by mass of the total amount of polyether polyol (A1), but it is more preferably 0 to 90% by mass, and even more preferably 0 to 80% by mass. There are no particular restrictions on the proportion of the oxypropylene group in the total amount of 100% by mass of the oxyalkylene groups, but it is preferably 5 to 100% by mass, more preferably 10 to 100% by mass, and even more preferably 20 to 100% by mass.

[0012] There are no particular restrictions on the total proportion of the oxyethylene group and the oxypropylene group in 100% by mass of the total amount of polyether polyol (A1), but from the viewpoint of achieving a good curing rate, it is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, and even more preferably 70 to 100% by mass.

[0013] There are no particular restrictions on the proportion of the oxypropylene group in 100% by mass of the total amount of polyether polyol (A1), but from the viewpoint of achieving a good curing rate, it is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, and even more preferably 70 to 100% by mass.

[0014] There are no particular restrictions on the polyether polyol (A1), and examples include AO addition polymers obtained by ring-opening addition polymerization of an AO containing at least one of EO and PO to a polyhydric alcohol as an initiator. There are no particular restrictions on the proportion of EO units in 100% by mass of the total amount of polyether polyol (A1), but it is preferably 0 to 95% by mass, more preferably 0 to 90% by mass, and even more preferably 0 to 80% by mass. There are no particular restrictions on the proportion of PO units in 100% by mass of the total amount of polyether polyol (A1), but it is preferably 5 to 100% by mass, more preferably 10 to 100% by mass, and even more preferably 20 to 100% by mass. There are no particular restrictions on the total proportion of EO units and PO units in 100% by mass of the total amount of polyether polyol (A1), but it is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, and even more preferably 70 to 100% by mass. There are no particular restrictions on the proportion of EO units in 100% by mass of the total amount of AO units, but it is preferably 0 to 95% by mass, more preferably 0 to 90% by mass, and even more preferably 0 to 80% by mass. There are no particular restrictions on the proportion of PO units in 100% by mass of the total amount of AO units, but it is preferably 5 to 100% by mass, more preferably 10 to 100% by mass, and even more preferably 20 to 100% by mass. There are no particular restrictions on the total amount of EO units and PO units in 100% by mass of the total amount of AO units, but it 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 in 100% by mass of the total amount of AO units is 80% by mass or more, the thermal conductivity and elongation at break are excellent, the curing rate is appropriate, and a cured product suitable for a heat dissipation material is obtained.

[0015] When two or more AOs are added using ring-opening methods, the arrangement of units derived from each AO may be random, block, or tapered. When the arrangement of EO and PO units is random, the structure may typically consist of block bodies of PO units and random bodies of EO and PO units, or it may consist of block bodies of EO units and random bodies of EO and PO units. When the arrangement of EO and PO units is block, the structure may consist of block bodies of PO units, block bodies of EO units, and block bodies of PO units in this order ("PO block - EO block - PO block" structure), or it may consist of block bodies of EO units, block bodies of PO units, and block bodies of EO units in this order ("EO block - PO block - EO block" structure). Furthermore, when the arrangement of EO units and PO units is tapered, it typically has block bodies of PO units, random bodies of EO units and PO units, and block bodies of EO units.

[0016] The content of EO units and PO units relative to the total amount of AO units present in polyether polyol (A1) is: １３ This can be calculated by determining the monomer unit composition of the oxyalkylene chain using C-NMR. For example, if polyether polyol (A1) is a polyol composed of PO units and EO units, the content of EO units and PO units can be determined from the area ratio of the methyl group signal in the PO units and the methylene group signals in the PO units and EO units. Alternatively, the content of AO units such as PO units and EO units present in the obtained polyether polyol (A1) can be calculated from the amount of each AO charged during the production of polyether polyol (A1).

[0017] The polyhydric alcohol as the initiator is not particularly limited. For example, dihydric alcohols such as water, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,4-butanediol, 1,6-hexanediol; trihydric alcohols such as glycerin, trimethylolpropane, 1,2,6-hexanetriol; tetrahydric alcohols such as pentaerythritol, diglycerin, tetramethylolcyclohexane, methyl glucoside; hexahydric alcohols such as sorbitol, mannitol, dulcitol; octahydric alcohols such as sucrose; etc. can be mentioned. These may be used alone or in combination of two or more. Among these, from the viewpoint of excellent flexibility and good elongation at break, dipropylene glycol, polypropylene glycol, and glycerin are preferable.

[0018] Amine polyols or polyols having an amino group using an amine compound as the initiator are not included in the polyether polyol (A1). The total amount of the units derived from the polyhydric alcohol as the initiator and the AO units in the polyether polyol (A1) is not particularly limited, but is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, even more preferably 99% by mass or more, and may be 100% by mass.

[0019] The number average molecular weight (Mn) of the polyether polyol (A1) is 1,100 or more. When it is 1,100 or more, the elongation at break is improved, and a cured product excellent in thermal conductivity and elongation at break can be obtained. Also, 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 not particularly limited, but is preferably 1,100 to 20,000, more preferably 1,100 to 12,000, still more preferably 1,100 to 10,000, and even more preferably 1,100 to 5,000.

[0020] The content of the polyether polyol (A1) in 100% by mass of the polyol is 55% by mass or more. When it 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 excellent in thermal conductivity and elongation at break can be obtained. Also, the content of the polyether polyol (A1) in 100% by mass of the polyol may be 100% by mass, but from the viewpoint of exerting the effects caused by polyols other than the polyether polyol (A1), it is preferably 95% by mass or less. From these viewpoints, the content of the polyether polyol (A1) in 100% by mass of the polyol is not particularly limited, but is preferably 55 to 95% by mass, more preferably 55 to 85% by mass, and still more preferably 55 to 80% by mass.

[0021] The polyether polyol (A1) can be produced by a known method and is not particularly limited. For example, a method of adding AO to the polyhydric alcohol as the initiator by a known method can be mentioned. By adjusting the amount of AO used, the number average molecular weight can be made 1,100 or more.

[0022] <Amine polyol (A2)> The polyol may or may not contain an amine polyol (A2). The amine polyol (A2) is not particularly limited. For example, a polyether polyol obtained by subjecting an amine compound as an initiator to ring-opening addition polymerization of AO can be mentioned. The amine polyol (A2) enhances the activity of the urethanization reaction and contributes to the improvement of curability. Only one kind of the amine polyol (A2) may be used, or two or more kinds may be used in combination.

[0023] There are no particular restrictions on the amine compound used as an initiator. Examples 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, and diphenylmethanediamine. These may be used individually or in combination of two or more. Among these, aliphatic amine compounds and saturated cyclic amine compounds are preferred, and monoethanolamine and tolylenediamine are more preferred, in terms of their effect in enhancing the initial activity of the urethane reaction.

[0024] There are no particular restrictions on the AO used in the production of amine polyol (A2), and examples include EO, PO, and butylene oxide. These may be used individually or in combination of two or more. Among these, the use of PO alone or the combination of EO and PO is preferred. When used in combination, EO and PO may be mixed before reaction or reacted sequentially.

[0025] The proportion of the PO units in 100% by mass of the total amount of amine polyol (A2) is not particularly limited, but 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 amine polyol (A2) is not particularly limited, but is preferably 0 to 50% by mass, more preferably 0 to 20% by mass.

[0026] There are no particular restrictions on the number of hydroxyl groups in the amine polyol (A2), but it is preferably 2 to 6, more preferably 3 to 6, and even more preferably 3 to 4. If it is above the lower limit of the above range, the viscosity is easily kept low, so the viscosity when inorganic fillers are mixed can be reduced. There are no particular restrictions on the number-average molecular weight (Mn) of the amine polyol (A2), but from the viewpoint of curability of the curable composition, it is preferably 100 to 3,000, more preferably 200 to 2,000, even more preferably 300 to 1,000, and even more preferably 300 to 500.

[0027] The content of amine polyol (A2) in 100% by mass of polyol is not particularly limited as long as it is 45% by mass or less. However, from the viewpoint of improving the curability of the curable composition and obtaining a cured product with excellent thermal conductivity and elongation at break, it is preferably 3 to 40% by mass, more preferably 4 to 40% by mass, even more preferably 5 to 35% by mass, even more preferably 10 to 35% by mass, even more preferably 20 to 35% by mass, even more preferably 20 to 30% by mass, and even more preferably 20 to 27% by mass.

[0028] <Aliphatic polyhydric alcohol (A3) with Mn less than 1,100> Polyols may or may not contain aliphatic polyhydric alcohol (A3) with Mn less than 1,100 (hereinafter sometimes referred to as "aliphatic polyhydric alcohol (A3)"). The presence of the aliphatic polyhydric alcohol (A3) in the polyol has the effect of keeping its viscosity low. Only one type of aliphatic polyhydric alcohol (A3) may be used, or two or more types may be used in combination. There are no particular restrictions on the aliphatic polyhydric alcohol (A3), and examples 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. These may be used individually or in combination of two or more. Among these, propylene glycol and glycerin are preferred, with propylene glycol being more preferred.

[0029] The content of aliphatic polyhydric alcohol (A3) in 100% by mass of polyol is not particularly limited as long as it is 45% by mass or less. However, from the viewpoint of exhibiting the effects of the polyether polyol (A1) and amine polyol (A2), it is preferably 0 to 25% by mass, more preferably 0 to 20% by mass, even more preferably 0 to 15% by mass, even more preferably 0 to 10% by mass, even more preferably 0 to 5% by mass, even more preferably 0 to 1% by mass, and even more preferably 0% by mass.

[0030] <Polyether polyol (A4) with Mn less than 1,100> The polyol may or may not contain polyether polyol (A4) with Mn less than 1,100 (hereinafter sometimes referred to as "polyether polyol (A4)"). The inclusion of said polyether polyol (A4) in the polyol has the effect of adjusting the moldability and flexibility of the resulting cured product. Only one type of polyether polyol (A4) may be used, or two or more types may be used in combination.

[0031] The content of polyether polyol (A4) in 100% by mass of the total amount of polyol is 45% by mass or less. This allows the aforementioned polyether polyol (A1) to be 55% by mass or more, resulting in a cured product with excellent thermal conductivity and elongation at break. There are no particular restrictions on the polyether polyol (A4), and examples include polyether polyols obtained by addition polymerization of a C2-C4 AO to a C2-C20 polyhydric alcohol. There are no particular restrictions on the polyhydric alcohols having 2 to 20 carbon atoms. Examples 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. These may be used individually or in combination of two or more. Among these, ethylene glycol, propylene glycol, glycerin, and sucrose are preferred, and ethylene glycol, glycerin, and sucrose are more preferred. There are no particular restrictions on the AO, and examples include EO, 1,2- or 1,3-PO, 1,2-, 1,3-, 1,4- or 2,3-butylene oxide. These may be used individually or in combination of two or more. When two or more AOs are used in combination, the bonding method may be block addition, random addition, or a combination thereof. Among these, EO, 1,2- or 1,3-PO is preferred, 1,2- or 1,3-PO is more preferred, and EO and 1,2-PO is even more preferred. Furthermore, there are no particular restrictions on the polyether polyol (A4), and for example, commercially available products can be used.There are no particular restrictions on commercially available polyether polyols (A4), and examples include Sannix PP-200 [polypropylene glycol with Mn=200, manufactured by Sanyo Chemical Industries, Ltd.], Sannix PP-400 [polypropylene glycol with Mn=400, manufactured by Sanyo Chemical Industries, Ltd.], Sannix PP-600 [polypropylene glycol with Mn=600, manufactured by Sanyo Chemical Industries, Ltd.], and Sannix PP-950 [polypropylene glycol with Mn=950, manufactured by Sanyo Chemical Industries, Ltd.]. These may be used individually or in combination of two or more.

[0032] There are no particular restrictions on the content of polyether polyol (A4) in 100% by mass of the total amount of polyol, as long as it is 45% by mass or less, but it is preferably 0 to 45% by mass, and more preferably 10 to 45% by mass.

[0033] Polyether polyol (A4) can be produced by known methods, and there are no particular restrictions. For example, one method is to add AO to the polyhydric alcohol having 2 to 20 carbon atoms using a known method. By adjusting the amount of AO used, the number-average molecular weight can be reduced to less than 1100.

[0034] <Polycarbonate Polyol (A5)> The polyol may or may not contain polycarbonate polyol (A5). The polyol containing polycarbonate polyol (A5) has the effect of improving the heat resistance of the resulting cured product. Only one type of polycarbonate polyol (A5) may be used, or two or more types may be used in combination.

[0035] There are no particular restrictions on the polycarbonate polyol (A5), and for example, any available on the market can be used. There are no particular restrictions on commercially available polycarbonate polyols (A5), and examples include Kuraray Polyol C-590 [manufactured by Kuraray Co., Ltd.], Kuraray Polyol P-2010 [manufactured by Kuraray Co., Ltd.], Kuraray Polyol P-5010 [manufactured by Kuraray Co., Ltd.], Duranol T5652 [manufactured by Asahi Kasei Corporation], PCP-100L [manufactured by Tosoh Corporation], etc. One of these may be used alone, or two or more may be used in combination.

[0036] The content of polycarbonate polyol (A5) in 100% by mass of the total amount of polyol is not particularly limited as long as it is 45% by mass or less, but from the viewpoint of the flexibility of the resulting cured product, it is preferably 0 to 30% by mass, more preferably 0 to 25% by mass, and even more preferably 0 to 20% by mass.

[0037] <Castor Oil Polyol (A6)> The polyol may or may not contain castor oil polyol (A6). The inclusion of castor oil polyol (A6) in the polyol has the effect of improving the heat resistance of the resulting cured product. Only one type of castor oil polyol (A6) may be used, or two or more types may be used in combination.

[0038] There are no particular restrictions on the castor oil-based polyol (A6), and for example, any available on the market can be used. There are no particular restrictions on commercially available castor oil-based polyols (A6), and examples include URIC H30 [manufactured by Ito Oil Co., Ltd.], URIC H1830 [manufactured by Ito Oil Co., Ltd.], HS CM-025P [manufactured by Toyokuni Oil Co., Ltd.], HS CM-075P [manufactured by Toyokuni Oil Co., Ltd.], etc. One of these may be used alone, or two or more may be used in combination.

[0039] The content of castor oil-based polyol (A6) in 100% by mass of the total amount of polyol is not particularly limited as long as it is 45% by mass or less, but is preferably 0 to 30% by mass, more preferably 0 to 25% by mass, and even more preferably 0 to 20% by mass.

[0040] <Other Polyols> The polyol may or may not contain other polyols that do not fall under any of the aforementioned polyether polyols (A1), amine polyols (A2), aliphatic polyhydric alcohols (A3), polyether polyols (A4), polycarbonate polyols (A5), and castor oil-based polyols (A6). The other polyol may be used alone or in combination of two or more. There are no particular restrictions on the other polyols, and examples include polyester polyols, acrylic polyols, and polytetramethylene ether glycols. These may be used alone or in combination of two or more. The content of other polyols in 100% by mass of the total amount of polyol is not particularly limited as long as it is 45% by mass or less, but 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 be 0% by mass.

[0041] (Polyisocyanates) There are no particular restrictions on the polyisocyanates used. Examples include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and isocyanurates of these polyisocyanates. One type of polyisocyanate may be used, or two or more types may be used in combination.

[0042] There are no particular restrictions on the aliphatic polyisocyanate, and examples include chain-like aliphatic polyisocyanates having 4 to 20 carbon atoms. There are no particular restrictions on the chain-like aliphatic polyisocyanates having 4 to 20 carbon atoms, and examples include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate. These may be used individually or in combination of two or more.

[0043] There are no particular restrictions on the alicyclic polyisocyanate, and examples include alicyclic polyisocyanates having 6 to 17 carbon atoms. There are no particular restrictions on the above-mentioned alicyclic polyisocyanates having 6 to 17 carbon atoms, and examples include isophorone diisocyanate (IPDI), 4,4-dicyclohexylmethane diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexene-1,2-dicarboxylate, 2,5- or 2,6-norbornane diisocyanate, etc. These may be used individually or in combination of two or more. Furthermore, there are no particular restrictions on the alicyclic polyisocyanate, and for example, commercially available products can be used. There are no particular restrictions on commercially available alicyclic polyisocyanates, and examples include Desmodule I [manufactured by Sumika Covestro Urethane Co., Ltd.].

[0044] There are no particular restrictions on the aromatic polyisocyanate, and examples include aromatic polyisocyanates having 8 to 22 carbon atoms. There are no particular restrictions on the above aromatic polyisocyanates having 8 to 22 carbon atoms, and examples include 1,3- or 1,4-phenylenediisocyanate, 2,4- or 2,6-tolylenediisocyanate (TDI), 4,4'- or 2,4'-diphenylmethanediisocyanate (monomeric MDI), polynuclear monomers of monomeric MDI (polymethylene polyphenyl polyisocyanate, polymeric MDI), polyol-modified MDI, and m- or p-isocyanatophenylsulfonyl isocyanates. Examples include 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, α,α,α',α'-tetramethylxylylene diisocyanate (TMXDI), etc. These may be used individually or in combination of two or more.

[0045] Examples of polyisocyanate isocyanurates include trimers of polyisocyanates (such as the aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates mentioned above). There are no particular restrictions on the polyisocyanate isocyanurates used; for example, commercially available products can be used. There are no particular restrictions on commercially available polyisocyanate isocyanurates; for example, Duranate TLA-100 [manufactured by Asahi Kasei Corporation] can be used.

[0046] Among polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, isocyanurates of aliphatic polyisocyanates, and isocyanurates of alicyclic polyisocyanates are preferred from the viewpoint of excellent moldability. From the viewpoint of improving curability, aromatic polyisocyanates are more preferred, and 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and mixtures of 4,4'- and 2,4'-diphenylmethane diisocyanates are even more preferred. In 4,4'- or 2,4'-diphenylmethane diisocyanate, the isocyanate group is directly bonded to the aromatic ring, which is an electron-withdrawing group, resulting in very high reaction activity of the isocyanate group, which can further improve curability. Furthermore, from the viewpoint of having excellent storage stability for the curable composition and the second agent described later, aliphatic polyisocyanates and isocyanurates of aliphatic polyisocyanates are more preferred, hexamethylene diisocyanates and isocyanurates of hexamethylene diisocyanates are even more preferred, and isocyanurates of hexamethylene diisocyanates are even more preferred.

[0047] There are no particular restrictions on the content of polyisocyanate in 100% by mass of the curable composition, but from the viewpoint of improving curability and obtaining a cured product with excellent thermal conductivity and elongation at break, it is preferably 0.5 to 20% by mass, more preferably 1 to 10% by mass, and even more preferably 1.5 to 5.5% by mass. There are no particular restrictions on the total content of the above polyol and the above polyisocyanate in 100% by mass of the curable composition, but from the viewpoint of improving curability and obtaining a cured product with excellent thermal conductivity and elongation at break, it is preferably 3 to 30% by mass, more preferably 5 to 25% by mass, and even more preferably 5.5 to 15% by mass.

[0048] There are no particular restrictions on the isocyanate index represented by the following formula, but it is preferably 20 to 110. Isocyanate index = [NCO number] / [OH number] × 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 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, there are no particular restrictions on the isocyanate index, but it is more preferably 40 to 110, even more preferably 40 to 100, even more preferably 50 to 100, and even more preferably 70 to 100. Furthermore, although there are no particular restrictions on the isocyanate index, from the viewpoint of obtaining a cured product with an appropriate C hardness that can be suitably used in heat dissipation members and the like, it is more preferably 20 to 100, even more preferably 30 to 75, and even more preferably 40 to 57.

[0049] (Inorganic Fillers) There are no particular restrictions on inorganic fillers, and examples include metal oxides such as titanium dioxide, alumina, silica, zinc oxide, and magnesium oxide; metal carbonates such as calcium carbonate, magnesium carbonate, and hydrotalcite; metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; metal borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; metal nitrides such as aluminum nitride, boron nitride, and silicon nitride; and metals such as gold, silver, copper, and alloys containing these. These may be used individually or in combination of two or more. Among these, metals, metal oxides, metal nitrides, metal hydroxides, and metal carbonates are preferred from the viewpoint of good heat dissipation when the cured product of the curable composition is used as a heat dissipation member, metals, metal oxides, metal nitrides, metal hydroxides, and metal carbonates are preferred, metal oxides and metal hydroxides are more preferred, zinc oxide, alumina, magnesium oxide, and aluminum hydroxide are even more preferred, and zinc oxide, magnesium oxide, and aluminum hydroxide are even more preferred. Furthermore, from the viewpoint of providing flame retardancy (self-extinguishing properties), metal hydroxides are preferred, and aluminum hydroxide is more preferred. There are no particular restrictions on the amount of oil absorbed by the metal hydroxide, but it is preferably 40 mL / 100 g or less, more preferably 15 to 40 mL / 100 g, and even more preferably 20 to 30 mL / 100 g. If it is above the lower limit, the metal hydroxide and resin will blend well and tensile properties such as elongation at break will be easily exhibited, and if it is below the upper limit, the curable composition and the first and second agents described later tend to have low viscosity.

[0050] There are no particular restrictions on the shape of the inorganic filler, but it is preferably fibrous or particulate. These may be used individually or in combination of two or more. There are no particular restrictions on the particulate shape; examples include spherical, plate-shaped, needle-shaped, and irregularly shaped particles (obtained by crushing, etc.). These may be used individually or in combination of two or more. Among these, spherical is preferred from the viewpoint of excellent moldability.

[0051] When the inorganic filler is a spherical particle, the volume-average particle diameter (D50: the particle diameter at which the cumulative particle amount in the volume-based particle size distribution accounts for 50%) of the inorganic filler is not particularly limited, but from the viewpoint of excellent moldability, it is preferably 0.01 to 200 μm, more preferably 0.1 to 150 μm, and even more preferably 0.1 to 120 μm. The volume-average particle diameter of the inorganic filler can be measured using a laser diffraction particle size distribution analyzer [e.g., SALD-2000A, SALD-2300 from Shimadzu Corporation, LA-920 from Horiba, Ltd.]. If components other than the inorganic filler are dissolved in the solvent, the solution of the composition may be measured. Also, when obtaining the inorganic filler, if the volume-average particle diameter is known, that value may be used.

[0052] The inorganic filler content in 100% by mass of the curable composition is 50 to 90% by mass. If it is 50% by mass or more, the thermal conductivity of the cured product of the curable composition can be made good, and if it is 90% by mass or less, the moldability can be made good. From this viewpoint, there are no particular restrictions on the inorganic filler content in 100% by mass of the curable composition, but it 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 70 to 85% by mass. Also, there are no particular restrictions on the inorganic filler content per 100 parts by mass of polyol, but it is preferably 200 to 3000 parts by mass, more preferably 250 to 2000 parts by mass, and even more preferably 300 to 1500 parts by mass. If it is above the lower limit above, the thermal conductivity of the cured product of the curable composition can be made good, and if it is below the upper limit above, the moldability can be made good.

[0053] (Dehydrating agent) There are no particular restrictions on the dehydrating agent, and examples include calcium chloride, calcium oxide, calcium sulfate, silica gel, molecular sieves, etc. One of these may be used alone, or two or more may be used in combination. Among these, molecular sieves are preferred from the viewpoint of thermal stability at high temperatures.

[0054] There are no particular restrictions on the shape of molecular sieves, and examples include spherical, plate-shaped, needle-shaped, cylindrical, and irregularly shaped particles (obtained by crushing, etc.). These may be used individually or in combination of two or more. Among these, spherical is preferred from the viewpoint of excellent moldability. When the molecular sieves are spherical, there are no particular restrictions on the volume-average particle diameter (D50: the particle diameter at which the cumulative particle amount in the particle size distribution based on volume becomes 50%) of the molecular sieves, but from the viewpoint of dispersibility, it is preferably 1 to 50 μm, more preferably 1 to 20 μm, and even more preferably 1 to 10 μm. The volume-average particle diameter of molecular sieves can be measured using a laser diffraction particle size distribution analyzer [e.g., SALD-2000A, SALD-2300, Horiba, Ltd. LA-920]. If components other than molecular sieves are soluble in the solvent, the solution of the composition may be measured. Also, if the volume-average particle size is known when obtaining the molecular sieves, that value may be used.

[0055] There are no particular restrictions on the pore size of molecular sieves, but from the viewpoint of adsorbing water and carbon dioxide without adsorbing other molecules, it is preferably 0.1 to 1.0 nm, more preferably 0.2 to 0.7 nm, and even more preferably 0.3 to 0.5 nm.

[0056] The content of the dehydrating agent in 100% by mass of the curable composition is 0.05 to 5% by mass. If it is 0.05% by mass or more, it absorbs water in the curable composition, suppresses the generation of carbon dioxide, a by-reaction product of water and polyisocyanate, and as a result, can suppress the generation of bubbles in the cured product. If it is 5% by mass or less, the flexibility of the cured product can be maintained. From this viewpoint, there are no particular restrictions on the content of the dehydrating agent in 100% by mass of the curable composition as long as it is between 0.05 and 5% by mass, but it is preferably 0.5 to 4% by mass, and more preferably 1.5 to 3.5% by mass.

[0057] (Urethane Catalyst) The curable composition according to this embodiment may or may not further contain a urethane catalyst. Among these, it is preferable to include a urethane catalyst from the viewpoint of promoting urethane formation of the curable composition. Only one type of urethane catalyst may be used, or two or more types may be used in combination. There are no particular restrictions on the urethane catalyst, and examples include amine catalysts such as triethylenediamine, N-ethylmorpholine, diethylethanolamine, and 1,8-diazabicyclo(5.4.0)undecene-7; metal catalysts such as bismastris(2-ethylhexanoate), stannous octoate, dibutyltin dilaurate, and lead octoate; and so on. Only one type may be used, or two or more types may be used in combination. Furthermore, there are no particular restrictions on the urethane catalyst, and for example, commercially available ones can be used. There are no particular restrictions on commercially available urethane catalysts, and examples include inorganic bismuth catalysts [Nitto Chemical Industries, Ltd., Neostan U-600]. The content of the urethane catalyst is not particularly limited, but 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.

[0058] (Dispersant) The curable composition according to this embodiment may or may not contain a dispersant. Among these, it is preferable to include a dispersant from the viewpoint of stably dispersing the filler in the formulation even during storage. There are no particular restrictions on the dispersant, and examples include 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, glycerin fatty acid esters, etc. One of these may be used alone, or two or more may be used in combination.

[0059] [In general formula (1), R １ A is a hydrogen atom, an alkyl group having 2 to 18 carbon atoms, or an alkenyl group having 2 to 18 carbon atoms. 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 R３ (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 of 3 to 15). ]

[0060] R １ The alkyl group having 2 to 18 carbon atoms in R １ is not particularly limited, and examples thereof 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, an octadecyl group, etc. Further, the alkyl group having 2 to 18 carbon atoms in R

[0061] R １ may be linear or branched.

[0061] The alkenyl group having 2 to 18 carbon atoms in R １ is not particularly limited, and examples thereof include an ethenyl group, a propenyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, a heptadecenyl group, an octadecenyl group, etc. Further, the alkenyl group having 2 to 18 carbon atoms in R １ may be linear or branched. Furthermore, the position of the double bond of the alkenyl group having 2 to 18 carbon atoms in R １ is not limited.

[0063] In the general formula (1), A<000001 : 6>O represents an oxyalkylene group having 2 to 3 carbon atoms, and is not particularly limited; for example, an ethylene oxy group, a propylene oxy group, etc. Among these, the ethylene oxy group is preferred from the viewpoint of dispersibility. n1 is an integer from 3 to 15, and is not particularly limited, but from the viewpoint of good dispersibility of the inorganic filler and mechanical strength of the cured product, it is preferably 3 to 13, more preferably 4 to 11.

[0064] R ２ is a hydrogen atom or -(A ２ O) ｎ２ R ３ (R ３ A is an alkyl group having 2 to 18 carbon atoms, or an alkenyl group having 2 to 18 carbon atoms. ２ O is an oxyalkylene group with 2 to 3 carbon atoms, and n2 is an integer from 3 to 15. ３ For example, R １ Similar examples can be given, and the same applies to preferred examples. A ２ As for O, A １ The same items as in O are listed, and the preferred items are also the same. ２ If is a hydrogen atom, then the compound of general formula (1) is a monoester, and R ２ But - (A ２ O) ｎ２ R ３ Therefore, the compound of general formula (1) is a diester. Also, R ２ But - (A ２ O) ｎ２ R ３ In the case of R １ and R ３ n1 and n2 may be the same or different.

[0065] As a phosphate ester represented by general formula (1), R １ Two or more different types may be mixed and used, and monoester (R ２ H) and diester (R ２ But - (A ２ O) ｎ２ R ３A mixture of the above may be used. The phosphate ester represented by general formula (1) is generally obtained as a mixture of monoester and diester (mono-di mixture). In addition, salts of the phosphate ester represented by general formula (1) (metal salts such as sodium, potassium, magnesium; ammonium salts; etc.) may be used.

[0066] There are no particular restrictions on the phosphate ester represented by general formula (1), but preferably alkyl ether phosphate esters, alkyl phosphate esters, and more preferably alkyl ether phosphate esters. The phosphate ester represented by general formula (1) is obtained by phosphate esterification with polyether and phosphorus oxidized. There are no particular restrictions on the phosphate ester represented by general formula (1), and for example, commercially available products can be used. There are no particular restrictions on commercially available phosphate esters represented by general formula (1), and for example, Disparon DA-375 [manufactured by Kusumoto Chemical Co., Ltd.], Prysurf A208N [manufactured by Daiichi Kogyo Seiyaku Co., Ltd.], Phosphanol RL-210 [manufactured by Toho Chemical Industry Co., Ltd., R1, R3: C18H37, mono-di mixture, n1, n2: 2], Phosphanol RS-710 [manufactured by Toho Chemical Industry Co., Ltd., R １ , R ３ =: C12-C15 alkyl group, mono / di mixture, n1, n2:9], phosphanol RS-410 [manufactured by Toho Chemical Industry Co., Ltd., R １ , R ３ Examples include alkyl groups having 12 to 15 carbon atoms, mono-di mixtures, n1, n2:3, etc. These may be used individually or in combination of two or more.

[0067] There are no particular restrictions on the fatty acids having 12 to 24 carbon atoms. Examples include saturated fatty acids having 12 to 24 carbon atoms such as dodecanoic acid, hexadecanoic acid, eicosanoic acid, and tetracosanoic acid; and unsaturated fatty acids having 12 to 24 carbon atoms such as hexadecenoic acid (oleic acid), octadecenoic acid, and octadecanedienoic acid. These may be used individually or in combination of two or more. Among these, hexadecenoic acid (oleic acid) is preferred.

[0068] There are no particular restrictions on the sucrose fatty acid ester, and examples include esters of sucrose and fatty acids having 8 to 22 carbon atoms. One type of sucrose fatty acid ester may be used alone, or two or more types may be used in combination. Furthermore, there are no particular restrictions on the sucrose fatty acid ester, and for example, commercially available products may be used. There are no particular restrictions on commercially available sucrose fatty acid esters, and examples include sucrose stearate esters [DK ester F-50 (HLB=6), F-70 (HLB=8), F-110 (HLB=11), etc. manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and Ryoto sugar ester S-770 (HLB=approx. 7), S-970 (HLB=approx. 9), S-1170 (HLB=approx. 11), S-1170F (HLB=approx. 11), etc. manufactured by Mitsubishi Chemical Corporation]. One type of these may be used alone, or two or more types may be used in combination.

[0069] There are no particular restrictions on the sorbitan fatty acid ester, and examples include mono- to tryesters of sorbitan with fatty acids having 8 to 22 carbon atoms. One type of sorbitan fatty acid ester may be used, or two or more types may be used in combination. Furthermore, there are no particular restrictions on the sorbitan fatty acid ester, and for example, commercially available products can be used. There are no particular restrictions on commercially available sorbitan fatty acid esters, and examples include sorbitan palmitate [Leodor TW-S120V (HLB=14.9), SP-P10 (HLB=6.7), etc., manufactured by Kao Corporation, and Rikemar P-300 (HLB=5.6), etc., manufactured by Riken Vitamin Co., Ltd.], sorbitan oleic acid monoester, fatty acid sorbitan ester [Ionet S-80, manufactured by Sanyo Chemical Industries, Ltd.], polyoxyethylene sorbitan fatty acid ester [Ionet T-60V, manufactured by Sanyo Chemical Industries, Ltd.], etc. These may be used individually or in combination of two or more types.

[0070] There are no particular restrictions on the glycerol fatty acid ester; for example, mono- to tryesters of polymers (degrees of polymerization 2 to 20) of glycerol or polyglycerol and fatty acids having 8 to 22 carbon atoms are used. Only one type of glycerol fatty acid ester may be used, or two or more types may be used in combination. Furthermore, there are no particular restrictions on the soglycerol fatty acid ester; for example, those available on the market can be used. There are no particular restrictions on commercially available glycerin fatty acid esters. Examples include diglycerin monolaurate [e.g., Poem DL-100 (HLB=9.4) manufactured by Riken Vitamin Co., Ltd.], diglycerin monomyristate [e.g., Poem DM-100 (HLB=8.7) manufactured by Riken Vitamin Co., Ltd.], diglycerin monostearate [e.g., Poem DS-100A (HLB=7.7) manufactured by Riken Vitamin Co., Ltd.], diglycerin monooleate [e.g., Poem DO-100V (HLB=7.3), Rikemar DO-100 (HLB=7.4) manufactured by Riken Vitamin Co., Ltd.], decaglycerin stearate [e.g., Poem J-0081HV (HLB=12), Poem J-0381V (HLB=12) manufactured by Riken Vitamin Co., Ltd.], etc. These may be used individually or in combination of two or more.

[0071] Among sucrose fatty acid esters, sorbitan fatty acid esters, and glycerol fatty acid esters, sorbitan fatty acid esters are preferred.

[0072] The total content of the phosphate ester represented by general formula (1) and the fatty acid having 12 to 24 carbon atoms in 100% by mass of the curable composition is not particularly limited, but from the viewpoint of dispersibility and moldability of the inorganic filler, it is preferably 1 to 5% by mass, more preferably 1 to 4% by mass, and even more preferably 1 to 2% by mass.

[0073] The total content of sucrose fatty acid ester, sorbitan fatty acid ester, and glycerin fatty acid ester in 100% by mass of the curable composition is not particularly limited, but from the viewpoint of dispersibility of inorganic fillers and moldability, it is preferably 1 to 5% by mass, more preferably 1 to 3% by mass, and even more preferably 1 to 2% by mass.

[0074] There are no particular restrictions on the dispersant, but from the viewpoint of dispersibility of inorganic fillers, it is preferable to include at least one selected from the group consisting of phosphate esters represented by general formula (1) 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.

[0075] The total amount of dispersant per 100 parts by mass of inorganic filler is not particularly limited, but is preferably 1 to 15 parts by mass, more preferably 1 to 10 parts by mass, and even more preferably 1 to 7 parts by mass. If the total amount of dispersant per 100 parts by mass of inorganic filler is above the lower limit, the dispersibility of the inorganic filler is excellent, and if it is below the upper limit, the moldability is excellent.

[0076] (Surfactants) The curable composition according to this embodiment may or may not contain surfactants. Among these, it is preferable to include a surfactant from the viewpoint of stably dispersing the fillers in the formulation even during storage. Only one type of surfactant may be used, or two or more types may be used in combination. There are no particular restrictions on the surfactant, but polyoxyalkylene-type nonionic surfactants, ester-type nonionic surfactants, anionic surfactants, and cationic surfactants are preferred.

[0077] There are no particular restrictions on the polyoxyalkylene-type nonionic surfactant, and examples include aliphatic alcohols (4 to 30 carbon atoms), alkyl (1 to 30 carbon atoms) phenols, aliphatic (4 to 30 carbon atoms) amines, or AO adducts of aliphatic (4 to 30 carbon atoms) amides (preferably with an addition mole of 1 to 30). These may be used individually or in combination of two or more. There are no particular restrictions on the aliphatic alcohol constituting the polyoxyalkylene-type nonionic surfactant, but are preferably n-, i-, sec-, or t-butanol, octanol, or dodecanol. There are no particular restrictions on the alkylphenol constituting the polyoxyalkylene-type nonionic surfactant, but are preferably phenol, methylphenol, or nonylphenol. There are no particular restrictions on the aliphatic amine constituting the polyoxyalkylene-type nonionic surfactant, but are preferably laurylamine or methylstearylamine. There are no particular restrictions on the aliphatic amide, but are preferably stearic acid amide.

[0078] There are no particular limitations on the ester-type nonionic surfactant, and examples include ester compounds of fatty acids having 4 to 30 carbon atoms (such as lauric acid, stearic acid, and oleic acid) and polyhydric alcohols other than sucrose, sorbitol, and glycerin. These may be used individually or in combination of two or more.

[0079] There are no particular restrictions on the anionic surfactant, and examples include carboxylate type, sulfate ester type, and sulfonate type. These may be used individually or in combination of two or more. There are no particular restrictions on the carboxylate type, and examples include alkali metal salts of the above fatty acids having 4 to 30 carbon atoms, alkali metal salts of polyoxyalkylene alkyl ether carboxylic acids, etc. These may be used individually or in combination of two or more. There are no particular restrictions on the sulfate ester type, and examples include alkali metal sulfate esters of the above aliphatic alcohols having 4 to 30 carbon atoms or AO adducts of aliphatic alcohols. These may be used individually or in combination of two or more. There are no particular restrictions on the sulfonate type, and examples include alkali metal sulfonate salts of alkylphenols, etc. These may be used individually or in combination of two or more. Furthermore, there are no particular restrictions on the sulfonate type, and for example, those available on the market can be used. There are no particular restrictions on commercially available sulfonate salts; for example, polyethercarboxylic acid [Kao Corporation, Kao Akipo RLM-100] is one such example.

[0080] There are no particular restrictions on the cationic surfactant, and examples include primary to tertiary amine salts and quaternary ammonium salts. These may be used individually or in combination of two or more. There are no particular restrictions on the primary to tertiary amine salts, and examples include hydrochlorides of aliphatic amines having 4 to 30 carbon atoms [primary (e.g., laurylamine), secondary (e.g., dibutylamine), tertiary (e.g., dimethylstearylamine)], and salts of triethanolamine with an inorganic acid (hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, etc.) of a monoester of a fatty acid having 4 to 30 carbon atoms. These may be used individually or in combination of two or more. There are no particular restrictions on the quaternary ammonium salts, and examples include inorganic salts of quaternary ammonium compounds having 4 to 30 carbon atoms (e.g., butyltrimethylammonium, diethyllaurylmethylammonium, dimethyldistearylammonium). These may be used individually or in combination of two or more. Furthermore, there are no particular restrictions on the quaternary ammonium salts, and for example, those available on the market can be used. There are no particular restrictions on commercially available quaternary ammonium salts; for example, Nopcospers 092 [manufactured by Sunopco Corporation, a cationic surfactant] is one such example.

[0081] The amount of surfactant in 100% by mass of the curable composition is not particularly limited, but 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.

[0082] (Plasticizer) The curable composition according to this embodiment may or may not contain a plasticizer. Among these, it is preferable to include a plasticizer from the viewpoint of lowering the viscosity when an inorganic filler is mixed and improving the mixability of the first and second components. Only one type of plasticizer may be used, or two or more types may be used in combination. There are no particular restrictions on the plasticizer, and examples include phthalate-based plasticizers such as diisononyl phthalate, di-(2-ethylhexyl) phthalate, diisodecyl phthalate, and butyl benzyl phthalate; and lipids such as di-(2-ethylhexyl) adipate, di-n-decyl adipate, di-(2-ethylhexyl) azelate, dibutyl sebacate, di-(2-ethylhexyl) sebacate, polyethylene glycol bis-2-ethylhexanoate, and diisononyl adipate. Examples include fatty acid ester plasticizers; phosphate ester plasticizers such as tributyl phosphate, tris(β-chloropropyl) phosphate, tri-(2-ethylhexyl) phosphate, and 2-ethylhexyldiphenyl phosphate; benzoic acid plasticizers such as polyethylene glycol benzoate; epoxy plasticizers such as epoxidized soybean oil; trimellitate plasticizers; pyromelitate plasticizers; polyester plasticizers; sulfonic acid ester plasticizers; and the like. These may be used individually or in combination of two or more. Furthermore, there are no particular restrictions on the plasticizers used; for example, those available on the market can be used. There are no particular restrictions on commercially available plasticizers, and examples include DINP (diisononyl phthalate) [manufactured by Aekyung Petrochemical], EB-300 (polyethylene glycol benzoate) [manufactured by Sanyo Chemical Industries, Ltd.], Monosizer PB-3A, PB-10, PB-800, W-83, W-85 [manufactured by DIC Corporation], DOA (bis(2-ethylhexyl) adipate) [manufactured by Mitsubishi Chemical Corporation], DINA (diisononyl adipate) [manufactured by Mitsubishi Chemical Corporation], etc. These may be used individually or in combination of two or more.

[0083] The content of plasticizer in 100% by mass of the curable composition is not particularly limited, but is preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass, and even more preferably 2 to 10% by mass.

[0084] (Other Components) The curable composition according to this embodiment may contain antioxidants, ultraviolet absorbers, colorants, silane coupling agents, and other components, or may not contain them, as long as they do not inhibit the curing of the present invention. These may be used individually or in combination of two or more. There are no particular restrictions on the antioxidant, and examples include hindered phenol compounds. There are no particular restrictions on the hindered phenol compounds, and examples include 4-[[4,6-bis(octylthio)-1,3,5-triazine-2-yl]amino]-2,6-di-tert-butylphenol, 2,2'-thiodiethylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], and the like. These may be used individually or in combination of two or more. Furthermore, there are no particular restrictions on the hindered phenol compound; for example, commercially available ones can be used. There are no particular restrictions on commercially available hindered phenol compounds; for example, Irganox 565 [manufactured by BASF Japan Ltd.] and Irganox 1135 [manufactured by BASF Japan Ltd.] are examples. These may be used individually or in combination of two or more. There are no particular restrictions on the ultraviolet absorber; for example, benzotriazole, benzophenone, salicylate, and acrylate types are examples. These may be used individually or in combination of two or more. There are no particular restrictions on the colorant; for example, organic pigments are examples. There are no particular restrictions on the organic pigment; for example, phthalocyanine blue, insoluble azo pigments, soluble azo pigments, and condensed azo pigments are examples. These may be used individually or in combination of two or more. Furthermore, there are no particular restrictions on the colorant; for example, commercially available ones can be used. There are no particular restrictions on commercially available colorants, such as ZA Blue #2200 [manufactured by Mikuni Pigment Co., Ltd.]. There are no particular restrictions on silane coupling agents, such as diphenyldimethoxysilane, decyltrimethoxysilane, phenyltrimethoxysilane, propyltrimethoxysilane, and hexyltrimethoxysilane.These may be used individually or in combination of two or more. Furthermore, there are no particular restrictions on the silane coupling agent; for example, commercially available ones can be used. There are no particular restrictions on commercially available silane coupling agents; for example, 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.], KBM-3063 [hexyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.], etc. The curable composition according to this embodiment may or may not contain a compound having a structure derived from an aromatic polycarboxylic acid or its anhydride having three or more carboxyl groups. When the compound is present, the content of the compound in 100% by mass of the curable composition is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less. The aforementioned polyol and polyisocyanate do not have a structure derived from an aromatic polycarboxylic acid having three or more carboxyl groups or its anhydride. The total content of the polyol, polyisocyanate, inorganic filler, urethane catalyst, dispersant, surfactant, and plasticizer in 100% by mass of the curable composition is not particularly limited, but is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 94% by mass or more.

[0085] (Dosage Form of Curable Composition) The curable composition according to this embodiment may be a one-component or two-component type. Among these, a two-component type is preferred from the viewpoint of keeping the viscosity low and ensuring sufficient contact between the curable composition and the coating surface of the object to be coated. In the case of a two-component type, it is preferable that it consists of a first component containing a polyol and a second component containing a polyisocyanate. Even in the case of a two-component curable composition, the preferred types and contents of each component are as described above.

[0086] The inorganic filler may be contained in either the first agent or the second agent, or in both the first agent and the second agent. Of these, it is preferable to contain it in both the first agent and the second agent from the viewpoint of good mixing of the first agent and the second agent. The amount of inorganic filler contained in the first agent, relative to 100% by mass of the total amount of inorganic filler contained in the first agent and the second agent, is not particularly limited, but is preferably 20 to 80% by mass, more preferably 30 to 75% by mass, even more preferably 40 to 70% by mass, and even more preferably 45 to 70% by mass.

[0087] In the case of a two-part system, the urethane catalyst is included only in the first component. In the case of a two-part system, the dispersant may be included in either the first or second component, or in both the first and second components. Among these, it is preferable to include it in the first component from the viewpoint of storage stability. In the case of a two-part system, the surfactant may be included in either the first or second component, or in both the first and second components. Among these, it is preferable to include it in the first component from the viewpoint of storage stability. In the case of a two-part system, the plasticizer may be included in either the first or second component, or in both the first and second components. Among these, it is preferable to include it in the second component from the viewpoint of viscosity reduction. In the case of a two-part system, the dehydrating agent may be included in either the first or second component, or in both the first and second components. Among these, it is preferable to include it in both the first and second components from the viewpoint of good mixing of the first and second components.

[0088] The content of the second agent relative to 100 parts by mass of the first agent is not particularly limited, but from the viewpoint of good mixing of the two agents, it is preferably 50 to 120 parts by mass, more preferably 50 to 110 parts by mass.

[0089] In the case of a two-component system, there are no particular restrictions on the viscosity of the first component, but it is preferably 50 to 500 Pa·s, more preferably 100 to 400 Pa·s, and even more preferably 150 to 350 Pa·s. If it is above the lower limit, separation due to particle sedimentation during storage is easily suppressed, and if it is below the upper limit, fluidity is improved and the material can be easily filled into fine details. The viscosity of the first component can be determined by the method described in the examples.

[0090] In the case of a two-component system, there are no particular restrictions on the viscosity of the second component, but it is preferably 50 to 500 Pa·s, more preferably 100 to 400 Pa·s, and even more preferably 150 to 350 Pa·s. If it is above the lower limit, separation due to particle sedimentation during storage is easily suppressed, and if it is below the upper limit, fluidity is improved and the material can easily fill into fine details. The viscosity of the second component can be determined by the method described in the examples.

[0091] (Method for producing curable composition) The curable composition can be suitably produced by mixing the above-mentioned components with the first agent and the second agent as described above.

[0092] [Heat Dissipation Member] The curable composition according to this embodiment yields a cured product with excellent thermal conductivity, elongation at break, and adhesion even when cured in a high-humidity environment, and is therefore not particularly limited, but is suitable for use as a heat dissipation member. The heat dissipation member according to this embodiment includes a cured product of the curable composition according to this embodiment. There are no particular limitations on the use of the above heat dissipation member, but it is suitable for heat-generating parts of electric vehicles (inverters, chargers, etc.), semiconductor elements, relay circuits, switching circuits, etc.

[0093] The present invention will be specifically described below based on examples. However, the present invention is not limited to the examples described later, and various modifications are possible as long as the gist of the invention is not changed. Examples 1 to 14 and 20 to 23 are examples, and examples 15 to 19 are comparative examples.

[0094] [Measurement Method] The measurement methods for various properties of each raw material and component are as follows.

[0095] (Number-average molecular weight (Mn)) Mn was measured in polystyrene equivalent by gel permeation chromatography (GPC) under the following conditions, and calculated from these values. [Measurement conditions] ・Equipment used: "HLC-8320GPC", manufactured by Tosoh Corporation ・Column used: "TSKgel® SuperMultiporeHZ-M", manufactured by Tosoh Corporation ・Detector: Differential refractive index (RI) detector ・Detection temperature: 40°C ・Eluent: Tetrahydrofuran ・Flow rate: 0.350 mL / min ・Sample concentration: 0.5% by mass ・Sample injection volume: 10 μL ・Standard sample: Polystyrene

[0096] (Hydroxyl value) The hydroxyl value was determined in accordance with Method B (potentiometric automatic titration) of JIS K 1557-1:2007.

[0097] (EO unit content and PO unit content) The amount of EO and the amount of PO added in 100% by mass of the total amount of raw materials used in the synthesis of the polyol were considered to be the EO unit content and PO unit content of the polyol, respectively.

[0098] (Oil absorption by metal hydroxides) Oil absorption was measured in accordance with the boiled linseed oil method of JIS K 5101-13-1 (2004), with the boiled linseed oil used in the test replaced with DOA (dioctyl adipate).

[0099] [Synthesis Example 1 (Polyol 1)] 1000 g of polypropylene glycol, obtained by adding 5.6 moles of PO to propylene glycol as an initiator, and 28 g of a 48% by mass potassium hydroxide aqueous solution as a catalyst were added to a pressure vessel. After purging the vessel with nitrogen, the reaction mixture was heated to 105°C while stirring, and 5250 g of PO was added and the reaction proceeded. After confirming that the internal pressure had stopped changing, 6 g of adsorbent (synthetic magnesium silicate, KW1000, manufactured by Kyowa Chemical Industry Co., Ltd.) was added to neutralize and remove the catalyst, yielding polyol 1 (number average molecular weight 2,000, number of functional groups 2, hydroxyl value 56 mg KOH / g, proportion of oxypropylene groups 100% by mass (proportion of oxyethylene groups 0% by mass), proportion of initiator units 3.8% by mass).

[0100] [Raw materials for the curable composition] The following were used as raw materials for the curable composition: (Polyether polyol (A1)) Polyol 1: Polyether polyol (A1) obtained in Synthesis Example 1.

[0101] (Polyether polyols (A4) with Mn less than 1,100) (1) Polyol 2: A polyether polyol obtained by adding 9.0 moles of PO to a mixture of scroll and glycerin at 88% by mass / 12% by mass as an initiator, with a hydroxyl value of 450 mg KOH / g and a number average molecular weight of 520. (2) Polyol 5: A polyether polyol obtained by adding glycerin PO, with a hydroxyl value of 400 mg KOH / g and a number average molecular weight of 950, manufactured by Sanyo Chemical Industries, Ltd., under the name Sannix GP400.

[0102] (Polycarbonate polyol (A5)) Polyol 3: Hydroxyl value 224.4 mg KOH / g, number average molecular weight 500, Kuraray Polyol C-590, manufactured by Kuraray Co., Ltd.

[0103] (Castor oil-based polyol (A6)) Polyol 4: Polyol 4: Hydroxyl value 160 mg KOH / g, number average molecular weight 950, URIC H30, manufactured by Ito Oil Co., Ltd.

[0104] (Polyisocyanates) (1) Polyisocyanate B1: A mixture of 4,4'-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, and trimethyl phosphate modified with polyol, NCO content 23.1% by mass, Coronate 1050, manufactured by Tosoh Corporation. (2) Polyisocyanate B2: Trimer of hexamethylene diisocyanate, NCO content 23.2% by mass, Duranate TLA-100, manufactured by Asahi Kasei Corporation. (3) Polyisocyanate B3: Polymeric MDI (polymethylene polyphenyl polyisocyanate), NCO content 30.0-32.0% by mass, M20S, manufactured by BASF INOAC Polyurethane Co., Ltd.

[0105] (Inorganic Fillers) (1) Inorganic filler C1: Aluminum hydroxide, spherical, volume average particle size (D50) 61 μm, oil absorption capacity 19 mL / 100 g, SBX73, manufactured by Nippon Light Metal Co., Ltd. (2) Inorganic filler C2: Aluminum hydroxide, spherical, volume average particle size (D50) 6 μm, oil absorption capacity 29 mL / 100 g, BX053, manufactured by Nippon Light Metal Co., Ltd. (3) Inorganic filler C3: Magnesium oxide, spherical, volume average particle size (D50) 40-70 μm, RF-50-FC, manufactured by Ube Materials Co., Ltd. (4) Inorganic filler C4: Magnesium oxide, spherical, volume average particle size (D50) 70-120 μm, RFA-100-FC, manufactured by Ube Materials Co., Ltd. (5) Inorganic filler C5: Zinc oxide, spherical, volume average particle size (D50) 70 μm, LPZINC-50S, manufactured by Sakai Chemical Industry Co., Ltd. (6) Inorganic filler C6: Graphite, flake-like, volume average particle size (D50) 50 μm, Z-50, manufactured by Ito Graphite Industry Co., Ltd. (7) Inorganic filler C7: Aluminum hydroxide, amorphous, volume average particle size (D50) 21 μm, oil absorption capacity 21 mL / 100 g, CW-325LV, manufactured by Sumitomo Chemical Co., Ltd. (8) Inorganic filler C8: Aluminum hydroxide, amorphous, volume average particle size (D50) 10 μm, oil absorption capacity 28 mL / 100 g, CW-310LV, manufactured by Sumitomo Chemical Co., Ltd. (9) Inorganic filler C9: Aluminum hydroxide, amorphous, volume average particle size (D50) 12 μm, oil absorption 34 mL / 100 g, CL-310, manufactured by Sumitomo Chemical Co., Ltd. (10) Inorganic filler C10: Aluminum hydroxide, amorphous, volume average particle size (D50) 4 μm, oil absorption 39 mL / 100 g, CL-303, manufactured by Sumitomo Chemical Co., Ltd.

[0106] (Dehydrating agents) (1) Dehydrating agent D1: Zeolite, spherical, volume average particle size (D50) 3-7 μm, pore size 0.35 nm, molecular sieve powder 3AB, manufactured by Resonaq Universal Co., Ltd. (2) Dehydrating agent D2: Zeolite, spherical, volume average particle size (D50) 3-7 μm, pore size 0.4 nm, molecular sieve powder 4A, manufactured by Resonaq Universal Co., Ltd. (3) Dehydrating agent D3: Zeolite, spherical, volume average particle size (D50) 3-7 μm, pore size 0.5 nm, molecular sieve powder 5A, manufactured by Resonaq Universal Co., Ltd. (4) Dehydrating agent D4: Zeolite, spherical, volume average particle size (D50) 3-7 μm, pore size 0.3 nm, molecular sieve powder 3A, manufactured by Resonaq Universal Co., Ltd. (5) Dehydrating agent D5: Silica gel, spherical, volume average particle size (D50) 5.5 μm, SYLYSIA660, manufactured by Fuji Silysia Chemical Co., Ltd.

[0107] (Urethane catalyst) Urethane catalyst E1: Bismastris (2-ethylhexanoate), Bi content 18.0-19.0% by mass, Neostan U-600, manufactured by Nitto Kasei Co., Ltd.

[0108] (Dispersant) (1) Dispersant F1: Polyoxyethylene alkyl ether phosphate ester (R １ , R ３ : C12-C15 alkyl group, EO 9 molar addition), phosphanol RS-710, manufactured by Toho Chemical Industry Co., Ltd. The phosphate ester component is "R １ , R ３ The description "12-15 C1 alkyl group, EO 9 mole addition" refers to the R in general formula (1). １ is an alkyl group having 12 to 15 carbon atoms, R ３ A is an alkyl group having 12 to 15 carbon atoms. １ O and A ２ O means an oxyalkylene group (oxyethylene group (EO)) with 2 carbon atoms, and n1 and n2 are 9. (2) Dispersant F2: Polyoxyethylene sorbitan fatty acid ester, Leodol TW-S120V, manufactured by Kao Corporation.

[0109] (Surfactants) (1) Surfactant G1: Sodium polyoxyethylene lauryl ether acetate, manufactured by Kao Corporation: Kao Akipo RLM-100.

[0110] (Plasticizers) (1) Plasticizer H1: Benzoic acid ester type, Monosizer PB-3A, manufactured by DIC Corporation. (2) Plasticizer H2: Bis(2-ethylhexyl) adipate, DOA, manufactured by Mitsubishi Chemical Corporation. (3) Plasticizer H3: Diisononyl adipate, DINA, manufactured by Mitsubishi Chemical Corporation.

[0111] (Coloring agent) Coloring agent I1: ZA Blue #2200, a mixture of blue pigment dispersed in polyol 1, manufactured by Mikuni Pigment Co., Ltd.

[0112] (Antioxidant) Antioxidant J1: 4-[[4,6-bis(octylthio)-1,3,5-triazine-2-yl]amino]-2,6-di-tert-butylphenol, Irganox 565, manufactured by BASF Japan Ltd.

[0113] (Silane coupling agent) Silane coupling agent K1: Diphenyldimethoxysilane, KBM-202SS, manufactured by Shin-Etsu Chemical Co., Ltd.

[0114] [Preparation of the first and second agents] The first and second agents were mixed using a planetary mixer "T.K. HIVIS MIX Model 2P-03, manufactured by Primix Corporation" according to the proportions shown in Table 1.

[0115] [Measurement of physical properties of the first and second agents] The following measurements were performed on the obtained first and second agents. The measurement results are shown in Table 1.

[0116] (Viscosity) The shear viscosity (in Pa·s) of the obtained first and second agents at 25°C at a shear rate of 1.0 s⁻¹ was measured using a rheometer "MCR-701, manufactured by Anton Paar". However, in the case of the first agent in Example 19, this measurement could not be performed because it did not become a paste and could not be mixed uniformly (measurement impossible).

[0117] (Storage Stability (Second Agent Only)) The obtained second agent was divided into 10 g portions in 100 mL containers to make it susceptible to the influence of outside air, and the viscosity was measured after 7 days, 14 days, and 28 days. In all samples, a tendency for viscosity to increase over time was confirmed and evaluated according to the following evaluation criteria. The longer the period until the viscosity of the second agent reaches 500 Pa·s, the higher the storage stability can be said to be. [Evaluation Criteria] A: Maintained a viscosity of 500 Pa·s or less until 28 days. B: Maintained a viscosity of 500 Pa·s or less until 14 days. C: Maintained a viscosity of 500 Pa·s or less until 7 days. D: Exceeded 500 Pa·s by 7 days.

[0118] (Isocyanate Index) Using the obtained first and second agents, the isocyanate index was calculated from the following formula: Isocyanate Index = [NCO number] / [OH number] × 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

[0119] [Preparation of Curable Compositions and Production of Sheet-Like Cured Products] (Examples 1 to 23) The first and second agents were mixed in a planetary agitator [Awatori Rentaro AR-250, manufactured by Shinky Co., Ltd.] to obtain the curable compositions of Examples 1 to 23, according to the first agent / second agent mixing ratio shown in Table 1. Next, each curable composition was poured into a molding mold (20 cm long x 20 cm wide x 0.2 cm deep), pressed by closing the mold, and allowed to react at 25°C for 24 hours. After that, the molds were demolded to obtain the sheet-like cured products (sheet-like cured products) of Examples 1 to 23. The above operations were carried out in a room with a humidity of 62% (high humidity environment). In the case of the curable composition and sheet-like cured product of Example 19, production was not possible because the first agent did not become paste-like when mixing, and therefore could not be mixed uniformly.

[0120]

[0121] [Measurement of physical properties of sheet-like cured material] The following measurements were performed on the obtained sheet-like cured material. The measurement results are shown in Table 2. Note that the sheet-like cured material of Example 19 could not be manufactured, and therefore the following measurements could not be performed (measurement impossible).

[0122] (Foaming Properties 1 (Density)) The density of the sheet-like hardened material was calculated by measuring the weight of the hardened sheet and dividing it by the volume of the sheet-like hardened material. Foaming properties 1 (density) was evaluated according to the following criteria by comparing this measured value with the design value of density calculated from the specific gravity of each raw material. The higher the measured value / design value, the less air bubbles are formed and the better the heat dissipation may be. [Evaluation Criteria] A: Measured value / design value is 85% or more. B: Measured value / design value is more than 70% but less than 85%. C: Measured value / design value is 70% or less.

[0123] (Foaming 2 (Voids)) The obtained sheet-like cured material was cut into pieces measuring 5 cm long x 1 cm wide x 0.2 cm deep to obtain test pieces for measurement. The long side of the test piece was visually observed, and the number of voids (air bubbles) was counted and evaluated according to the following evaluation criteria. When voids (air bubbles) occur, heat dissipation decreases and they can become the starting point for delamination from the adherend, so it is preferable that the amount of voids (air bubbles) generated is small. [Evaluation Criteria] A: No voids (air bubbles) are generated B: 1 to 5 voids (air bubbles) are generated C: 6 or more voids (air bubbles) are generated

[0124] (Thermal Conductivity (W / m·K)) The obtained sheet-like cured material was cut into pieces measuring 1 cm long x 1 cm wide x 0.2 cm deep to obtain test pieces for measurement. The thermal conductivity (unit: W / m·K) of the test pieces was measured using the laser flash method with a thermal conductivity meter "Xenon Flash Analyzer LFA447 NanoFlash, manufactured by Netch Japan Co., Ltd.". The higher the thermal conductivity, the better the heat dissipation. Furthermore, if the measured value is greater than 2.0 W / m·K, the thermal conductivity is said to be particularly good; if it is between 1.5 and 2.0 W / m·K, the thermal conductivity is said to be sufficiently good; and if it is less than 1.5 W / m·K, the thermal conductivity is not said to be good.

[0125] (Elongation at Breaking (Tensile Elongation at Breaking) (%)) The obtained sheet-like hardened material was punched out using a No. 1 dumbbell as described in JIS K7312:1996, and the elongation at break (elongation at breaking) was measured as tensile elongation at breaking (%) in accordance with JIS K7312:1996 using a "Tensilon RTF-1310 testing machine, manufactured by A&D Co., Ltd." Furthermore, if the measured value is 10% or more, the elongation at breaking is said to be particularly excellent; if it is between 5.0% and less than 10%, the elongation at breaking is said to be sufficiently excellent; and if it is 5.0% or less, the elongation at breaking is not considered excellent.

[0126] (Adhesion (MPa)) Two aluminum plates measuring 25 mm in length and 100 mm in width were prepared. A 25 mm x 25 mm area of ​​the edge of one of the aluminum plates was coated with a 3 mm thick layer of the curable composition, which was made by mixing the first and second components. Next, the other aluminum plate was placed on top of the first plate so that the non-adhered portions of the two aluminum plates faced each other across the curable composition, and the area coated with the curable composition did not extend beyond the first plate. The test specimens were then left to stand at room temperature for 24 hours to prepare the specimens. The two prepared aluminum plates were each fixed to a "Tensilon RTF-1310 testing machine, manufactured by A&D Co., Ltd." The fixed specimens were pulled in the shear direction at a speed of 100 mm / min, and the stress at fracture was measured to evaluate the adhesion (MPa). A higher adhesion value (numerical value obtained by measurement) indicates better adhesion. Furthermore, if the measured value is 0.3 MPa or higher, the adhesion can be said to be particularly excellent; if it is between 0.1 MPa and 0.3 MPa, the adhesion can be said to be sufficiently excellent; and if it is 0.1 MPa or less, the adhesion cannot be said to be excellent.

[0127] (C Hardness) The C hardness value of the obtained 0.2 cm thick sheet-like cured material was measured using an "Asker Rubber Hardness Tester Type C, manufactured by Polymer Instruments Co., Ltd." There are no particular restrictions on the C hardness, but it is preferably 25 to 98, more preferably 35 to 70, and even more preferably 40 to 50. If it is above the lower limit, deformation due to external stress is easily suppressed, and if it is below the upper limit, damage to the material due to thermal expansion and contraction is easily suppressed, and the removal of adhering residue during rework is also easily facilitated.

[0128]

[0129] As can be seen from the measurement results shown in Table 2, the sheet-like cured products obtained by curing the curable composition of the present invention (Examples 1-14, 20-23) were found to have superior thermal conductivity, elongation at break, and adhesion compared to sheet-like cured products obtained by curing a curable composition other than the present invention (Examples 15-19), even when cured in a high-humidity environment. The curable composition of the present invention refers to a curable composition comprising a polyol, a polyisocyanate, an inorganic filler, and a dehydrating agent, wherein the polyol contains one or more selected from the group consisting of oxyethylene groups and oxypropylene groups and has a number average molecular weight of 1,100 or more, the polyether polyol content is 55% by mass or more in 100% by mass of the polyol, the inorganic filler content is 50-90% by mass in 100% by mass of the curable composition, and the dehydrating agent content is 0.05-5% by mass in 100% by mass of the curable composition.

Claims

1. A curable composition comprising a polyol, a polyisocyanate, an inorganic filler, and a dehydrating agent, wherein the polyol contains one or more selected from the group consisting of oxyethylene groups and oxypropylene groups and has 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, the content of the inorganic filler in 100% by mass of the curable composition is 50 to 90% by mass, and the content of the dehydrating agent in 100% by mass of the curable composition is 0.05 to 5% by mass.

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

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

4. The curable composition according to claim 1 or 2, wherein the polyisocyanate comprises at least one of an aliphatic polyisocyanate and an isocyanurate of an aliphatic polyisocyanate.

5. The curable composition according to claim 1 or 2, wherein the polyisocyanate comprises at least one of hexamethylene diisocyanate and an isocyanurate derivative of hexamethylene diisocyanate.

6. The curable composition according to claim 1 or 2, wherein the curable composition further comprises a urethane catalyst.

7. The curable composition according to claim 1 or 2, wherein the inorganic filler is one or more selected from the group consisting of metals, metal oxides, metal nitrides, metal hydroxides, and metal carbonates.

8. The curable composition according to claim 1 or 2, wherein the inorganic filler comprises a metal hydroxide.

9. The curable composition according to claim 1 or 2, wherein the inorganic filler comprises aluminum hydroxide.

10. The curable composition according to claim 7, wherein the oil absorption amount of the metal hydroxide is 40 mL / 100 g or less.

11. The curable composition according to claim 1 or 2, wherein the dehydrating agent is one or more selected from the group consisting of calcium chloride, calcium oxide, calcium sulfate, silica gel, and molecular sieves.

12. The curable composition according to claim 1 or 2, wherein the isocyanate index represented by the following formula is 40 to 57. Isocyanate index = [NCO number] / [OH number] × 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 13. The curable composition according to claim 1 or 2, comprising a first agent containing a polyol and a second agent containing a polyisocyanate.

14. The curable composition according to claim 1 or 2, for use in heat dissipation members.

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

16. The heat dissipating member according to claim 15, used in a heat-generating part of an electric vehicle.

Images