Curable composition, heat dissipation material, and article

Abstract

Provided is a curable composition which has a good dispersion state of an inorganic filler, is easy to apply, secures an appropriate pot life, has good shape retention immediately after application, and by being cured under a room temperature condition, is capable of forming a heat dissipation material that is excellent in terms of adhesion to the surface of a heating element, a radiator, or the like without using silicone and in which the adhesion is less likely to decrease even when heated. The present invention is a two-component curable composition which is used for forming a heat dissipation material. A main agent contains a polyamine (A), a polyol (C), an amino alcohol (D), and an inorganic filler (E1). A curing agent contains a polyisocyanate (B) and an inorganic filler (E2). The polyol (C) is an amorphous polyol having a side chain. The amino alcohol (D) is a compound having n primary amino groups and m secondary amino groups per molecule (each of n and m independently represents 0 or 1, and n + m = 0 does not occur).

Description

Curable composition, heat dissipating material, and article

[0001] The present invention relates to a curable composition, a heat dissipating material, and an article.

[0002] As integrated circuits become increasingly denser, the amount of heat generated inside electronic devices tends to increase, necessitating the development of technologies for efficiently dissipating heat generated inside electronic components. For example, thermal interface materials (TIMs), such as heat-dissipating sheets with excellent thermal conductivity, are known and placed between heat-generating elements, such as electronic components, and heat sinks or other heat sinks inside electronic devices. The use of such thermal interface materials fills the minute gaps between the surfaces of the heat-generating elements and the heat sink, reducing contact thermal resistance and enabling the heat from the heat-generating elements to be transferred appropriately to the heat sink.

[0003] For example, a heat-resistant elastic material in which a thermally conductive material is dispersed in a silicone polymer precursor has been proposed (Patent Document 1). However, there is a strong demand to avoid the use of silicone from the viewpoint of avoiding a decrease in insulating performance due to the generation of low-molecular-weight siloxane, which is a volatile component. For this reason, heat dissipation materials using non-silicone polymers as binder components and compositions for forming such heat dissipation materials have been studied.

[0004] For example, a thermally conductive polymer molded body has been proposed in which a polymerizable resin composition containing a polymerizable resin component such as a polyol and aluminum hydroxide is cured under heating conditions using a curing agent such as an isocyanate (Patent Document 2). Also proposed is a thermally conductive cured product in which a binder component containing a polyurethane polyurea resin having a carboxyl group and a thermally conductive filler is cured under heating conditions using an epoxy compound (Patent Document 3). Furthermore, a silicone-free thermal interface has been proposed in which a composition containing a component having a reactive functional group such as a polyol and a thermally conductive filler is heat-cured (Patent Document 4).

[0005] Japanese Patent Application Laid-Open No. 2005-209955 Japanese Patent Application Laid-Open No. 2015-530470 Japanese Patent Application Laid-Open No. 2020-200454 Japanese Patent Application Laid-Open No. 2023-508288

[0006] However, the conventional compositions proposed in Patent Documents 2 to 4 all require curing under heating conditions, which requires a heat source to be secured in the device production line. This makes the process of placing the heat dissipation material in the desired location complicated, and also poses problems such as the time required for curing, which are not favorable for carbon neutral initiatives.

[0007] In addition, since conventional compositions have relatively high fluidity, they tend to spread quickly when applied to target areas such as SUS plates and circuit boards. As a result, the applied shape may not be maintained and the composition may spread to areas where it should not be applied, making it difficult to place the heat dissipation material in the desired location. Furthermore, cured products such as heat dissipation materials formed using conventional compositions tend to have poor adhesion to target areas when heated, and improvements have been sought.

[0008] The present invention has been made in consideration of the problems of the prior art, and its object is to provide a curable composition that has a good dispersion state of the inorganic filler, is easy to apply, has an appropriate pot life, has good shape retention immediately after application, and is capable of curing under room temperature conditions to form a heat dissipation material that has excellent adhesion to the surfaces of heating elements, radiators, etc. without using silicone and that is resistant to deterioration of adhesion even when heated. Another object of the present invention is to provide a heat dissipation material that is a cured product obtained by curing the above-mentioned curable composition, and an article using this heat dissipation material.

[0009] That is, according to the present invention, there is provided the following curable composition: [1] A two-component curable composition used to form a heat dissipating material, comprising a combination of a main agent and a curing agent, wherein the main agent contains a polyamine (A), a polyol (C), an aminoalcohol (D), and an inorganic filler (E1), the curing agent contains a polyisocyanate (B) and an inorganic filler (E2), the amine value of the polyamine (A) is 300 mg KOH / g or less, the polyol (C) is an amorphous polyol having, in its molecule, a side chain branched from the main chain, and the aminoalcohol (D) has, in its molecule, n units of 1-methyl-2-propanol. [2] The curable composition according to [1], wherein the polyamine (A) is a compound having a primary amino group and m secondary amino groups (n and m each independently represent 0 or 1, and n + m = 0 is not satisfied), the content of the amino alcohol (D) in the main component is 0.005 to 1 mass% based on the total of the polyamine (A), the polyol (C), and the amino alcohol (D), and the ratio (NCO / (NH + OH)) of the number of moles of isocyanate groups in the curing agent to the total number of moles of amino groups and hydroxyl groups in the main component is 0.75 to 2.00. [3] The curable composition according to [1] or [2], wherein the polyisocyanate (B) is an aliphatic polyisocyanate. [4] The curable composition according to any one of [1] to [3], wherein the inorganic filler (E1) and the inorganic filler (E2) are each independently at least one selected from the group consisting of metals, metal oxides, metal nitrides, metal hydroxides, and metal carbonates. [5] The curable composition according to any one of [1] to [3], wherein the inorganic filler (E1) and the inorganic filler (E2) are each independently at least one selected from the group consisting of alumina, aluminum nitride, aluminum hydroxide, magnesium oxide, zinc oxide, boron nitride, and magnesium hydroxide.[6] The curable composition according to any one of [1] to [5], wherein the filling rate of the inorganic filler (E1) in the base agent is 70 to 95 mass%, and the filling rate of the inorganic filler (E2) in the curing agent is 50 to 95 mass%.

[0010] The present invention also provides the following heat dissipation materials: [7] A heat dissipation material that is a cured product obtained by curing the curable composition according to any one of [1] to [6] above. [8] The heat dissipation material according to [7] above, which has a thermal conductivity of 2.0 W / (m K) or more. [9] The heat dissipation material according to [7] or [8] above, in which the total filling rate of the inorganic filler (E1) and the inorganic filler (E2) is 65 to 95 mass%.

[0011] Furthermore, the present invention provides the following article:

[10] An article comprising a heat generating element or a heat radiator, and the heat dissipation material according to any one of [7] to [9] above, which is placed in contact with the heat generating element or the heat radiator.

[0012] According to the present invention, it is possible to provide a curable composition that has a good dispersion state of the inorganic filler, is easy to apply, has an appropriate pot life, has good shape retention immediately after application, and is capable of forming a heat dissipation material that, when cured at room temperature, has excellent adhesion to the surfaces of heating elements, radiators, etc., even without using silicone, and that is resistant to deterioration of adhesion even when heated. Furthermore, according to the present invention, it is possible to provide a heat dissipation material that is a cured product obtained by curing the above-mentioned curable composition, and an article using this heat dissipation material.

[0013] <Curable Composition> Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments. One embodiment of the curable composition of the present invention is a two-component curable composition used to form a heat dissipation material, comprising a combination of a base agent and a curing agent. The base agent contains a polyamine (A), a polyol (C), an aminoalcohol (D), and an inorganic filler (E1). The curing agent (hereinafter also referred to as "liquid B" or "second agent") contains a polyisocyanate (B) and an inorganic filler (E2). The polyamine (A) has an amine value of 300 mg KOH / g or less, and the polyol (C) is an amorphous polyol having a side chain branched from the main chain in its molecule. The aminoalcohol (D) is a compound having n primary amino groups and m secondary amino groups in its molecule (n and m each independently represent 0 or 1, and n + m = 0 is not satisfied). In the base resin, the content of the amino alcohol (D) in the total of the polyamine (A), polyol (C), and amino alcohol (D) is 0.005 to 1 mass %. The ratio (NCO / (NH+OH)) of the number of moles of isocyanate groups (NCO) in the curing agent to the total number of moles of amino groups and hydroxyl groups (NH+OH) in the base resin is 0.75 to 2.00. The curable composition of this embodiment will be described in detail below.

[0014] (Main Agent (Liquid A)) The curable composition of this embodiment is a two-part curing composition containing a combination of a main agent and a curing agent, and is a composition set of the type in which the two parts (two components) are mixed and then cured under specified conditions. The main agent (hereinafter also referred to as "Liquid A" or "First Agent") contains polyamine (A), polyol (C), aminoalcohol (D), and inorganic filler (E1), and is preferably a composition substantially composed only of polyamine (A), polyol (C), aminoalcohol (D), and inorganic filler (E1). The main agent is preferably a solvent-free composition that does not substantially contain a liquid medium.

[0015] The polyamine (A) is a component having two or more amino groups in its molecule, which reacts with the polyisocyanate (B) in the curing agent to form a urea bond. The amino groups in the polyamine (A) and the amino alcohol (D) react with the isocyanate groups in the polyisocyanate (B) faster than the hydroxyl groups in the polyol (C). Therefore, by using the polyamine (A) and the amino alcohol (D), urea bonds are quickly formed, and a heat dissipation material can be formed that exhibits shape retention and adhesion immediately after coating and that is resistant to deterioration of adhesion due to heating.

[0016] In addition, the polyamine (A) also functions as a dispersant for uniformly dispersing the inorganic filler (E1) in a good state in the base resin. Therefore, by using the polyamine (A), it is possible to increase the filling rate (content) of the inorganic filler (E1), and it is possible to form a heat dissipation material that is a cured product that is excellent in thermal conductivity and is less likely to have uneven physical properties such as thermal conductivity and adhesion.

[0017] When a base agent containing a dispersant (excluding polyamine (A)) that disperses the inorganic filler is used, the dispersant may bleed out from the formed heat dissipation material, which may lead to a decrease in the adhesion of the heat dissipation material. In contrast, the polyamine (A), which can also function as a dispersant, is incorporated into the molecules of the polymer (polyurethane polyurea resin) by reacting with the polyisocyanate (B), so it does not bleed out from the formed heat dissipation material. Therefore, by using a base agent that does not substantially contain a dispersant (excluding polyamine (A)) that disperses the inorganic filler (E1), it is expected that the dispersant will not bleed out from the formed heat dissipation material and that a heat dissipation material in which the decrease in adhesion over time is suppressed will be formed.

[0018] The amine value of the polyamine (A) is 300 mgKOH / g or less, preferably 20 to 250 mgKOH / g, and more preferably 70 to 200 mgKOH / g. Polyamine (A) with an amine value of more than 300 mgKOH / g has a small molecule and therefore tends to have an increased reaction rate. As a result, heat is easily generated during curing, and the usable time is shortened.

[0019] The base agent may contain two or more polyamines (A). When the base agent contains two or more polyamines (A), the "amine value of the polyamine (A)" is the maximum value (maximum amine value) among the amine values ​​of the two or more polyamines.

[0020] The polyol (C) is a component having two or more hydroxyl groups in its molecule, which reacts with the polyisocyanate (B) in the curing agent to form a urethane bond. The hydroxyl groups in the polyol (C) and the amino alcohol (D) react slower with the isocyanate groups in the polyisocyanate (B) than the amino groups in the polyamine (A). Therefore, by using the polyamine (A), the polyol (C), and the amino alcohol (D) in combination, urea bonds are rapidly formed and the initial physical properties are exhibited, and then the remaining polyisocyanate (B) reacts gently with the polyol (C) and the amino alcohol (D) to form a urethane bond. This makes it possible to form a heat dissipation material that has excellent adhesion while ensuring appropriate fluidity and a sufficient usable life, and in which deterioration of adhesion due to heating is suppressed.

[0021] The polyol (C) is an amorphous polyol having a side chain branched from the main chain in its molecule. When an amorphous polyol having a side chain is used, the side chain interacts with the inorganic filler, improving the dispersibility of the inorganic filler. This allows for a curable composition with a relatively low viscosity and easier use as a coating material. In contrast, when a crystalline polyol without a side chain, an amorphous polyol without a side chain, or a crystalline polyol with a side chain is used, the fluidity of the base component (liquid A) decreases and it becomes difficult to ensure a sufficient usable time.

[0022] Examples of amorphous polyols having side chains branched from the main chain in the molecule include short-chain diols such as 1,2-propylene glycol, 1,3-butylene glycol, 2-methylpropanediol, 3-methylpentanediol, 1,2-butanediol, and 1,2-hexanediol; polyester-based diols containing structural units derived from diols having branched alkyl chains such as neopentanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and 2-butyl-2-ethyl-1,3-propanediol; polycarbonate-based diols; polyether-based diols such as polypropylene glycol; polybutadiene polyols, etc. Castor oil polyols are particularly preferred because they have relatively low viscosity and long side chains in their molecules.

[0023] The hydroxyl value of the polyol (C) is not particularly limited and is typically 50 to 1,500 mgKOH / g. From the viewpoint of adjusting the reaction rate and usable life, it is preferably 80 to 1,250 mgKOH / g, and more preferably 100 to 600 mgKOH / g. If the hydroxyl value of the polyol (C) is too low, the reaction rate at room temperature tends to be slow, and it may be difficult to ensure normal adhesion. On the other hand, if the hydroxyl value of the polyol (C) is too high, the reaction rate at room temperature tends to be too fast, and the usable life may be shortened.

[0024] The amino alcohol (D) has n primary amino groups (-NH ２ ) and m secondary amino groups (-NH-) (n and m each independently represent 0 or 1, and n+m does not equal 0), and like polyamine (A), it is a component that reacts with polyisocyanate (B) in the curing agent to form a urea bond. By using such amino alcohol (D) in combination with polyamine (A), as described above, urea bonds are quickly formed, and shape retention and adhesion immediately after coating can be achieved, and a heat dissipation material can be formed in which deterioration of adhesion due to heating is suppressed. On the other hand, ２), or an amino alcohol having only a tertiary amino group in the molecule (n+m=0), it becomes difficult to obtain the desired properties (adhesion, shape retention, and adequate pot life).

[0025] The amino alcohol (D) is preferably a compound having one secondary amino group and one or two hydroxyl groups in its molecule (provided that the number of primary amino groups (n) is 0). By using such an amino alcohol (D), a more sufficient pot life can be ensured. Note that, when more rapid curing is desired, the amino alcohol (D) is preferably a compound having one primary amino group in its molecule (provided that the number of secondary amino groups (m) is 0 or 1).

[0026] Examples of the amino alcohol (D) include N-methylethanolamine, 2-ethylaminoethanol, mono-n-butylethanolamine, 3-methylamino-1,2-propanediol, monoethanolamine, diethanolamine, and N-(β-aminoethyl)ethanolamine.

[0027] In the base resin, the content of the amino alcohol (D) relative to the total of the polyamine (A), polyol (C), and amino alcohol (D) is 0.005 to 1 mass%, preferably 0.01 to 0.5 mass%, and more preferably 0.01 to 0.3 mass%. If the content of the amino alcohol (D) relative to the total of the polyamine (A), polyol (C), and amino alcohol (D) is less than 0.005 mass%, the shape retention immediately after application may be poor, or the adhesion may decrease when heated. On the other hand, if the content of the amino alcohol (D) relative to the total of the polyamine (A), polyol (C), and amino alcohol (D) is more than 1 mass%, the curing rate may be too fast, resulting in an insufficient pot life.

[0028] In the base resin, the content of polyamine (A) relative to the total of polyamine (A), polyol (C), and aminoalcohol (D) is preferably 30 to 90% by mass, more preferably 35 to 85% by mass, and particularly preferably 40 to 60% by mass. If the content of polyamine (A) relative to the total of polyamine (A), polyol (C), and aminoalcohol (D) is less than 30% by mass, curing may be somewhat difficult under room temperature (25°C) conditions, or the curing time may be somewhat prolonged. On the other hand, if the content of polyamine (A) relative to the total of polyamine (A), polyol (C), and aminoalcohol (D) is more than 90% by mass, the curing rate may be somewhat fast, and the usable time may be somewhat shortened. In addition, the content of the polyol (C) in the base resin relative to the total of the polyamine (A), the polyol (C), and the amino alcohol (D) is preferably 10 to 70 mass%, more preferably 15 to 65 mass%, and particularly preferably 40 to 60 mass%.

[0029] The inorganic filler (E1) in the base agent and the inorganic filler (E2) in the curing agent are both inorganic components having thermal conductivity. That is, both the base agent and the curing agent constituting the cured composition of this embodiment contain an inorganic filler. By including an inorganic filler in both the base agent and the curing agent, the base agent and the curing agent can be uniformly mixed, and a heat dissipation material can be formed, which is a cured product in which the inorganic filler is uniformly dispersed.

[0030] The inorganic filler (E1) in the base agent and the inorganic filler (E2) in the curing agent may be the same type or different types. The base agent contains a polyamine (A) that can also function as a dispersant. Therefore, the base agent can be filled (contained) with a relatively large amount of inorganic filler (E1). Specifically, the filling rate of inorganic filler (E1) in the base agent is preferably 70 to 95% by mass, more preferably 80 to 95% by mass. The filling rate of inorganic filler (E2) in the curing agent is preferably 50 to 95% by mass, more preferably 85 to 90% by mass.

[0031] The inorganic filler (E1) and the inorganic filler (E2) are preferably each independently at least one selected from the group consisting of metals, metal oxides, metal nitrides, metal hydroxides, and metal carbonates. Examples of metals (semimetals) include gold, silver, copper, aluminum, magnesium, zinc, boron, and alloys containing these. Examples of metal oxides include alumina, calcium oxide, magnesium oxide, zinc oxide, beryllia, titanium oxide, and silica. Examples of metal nitrides include aluminum nitride, boron nitride, carbon nitride, and silicon nitride. Examples of metal hydroxides include aluminum hydroxide, magnesium hydroxide, and calcium hydroxide. Examples of metal carbonates include calcium carbonate, magnesium carbonate, and hydrotalcite. The inorganic fillers can be used alone or in combination. Among these, alumina, aluminum nitride, aluminum hydroxide, magnesium oxide, zinc oxide, boron nitride, and magnesium hydroxide are preferred.

[0032] Examples of the particle shape of the inorganic filler (E1) and the inorganic filler (E2) include spherical, acicular, flaky, dendritic, fibrous, and amorphous shapes. The average particle diameter of the inorganic filler (E1) and the inorganic filler (E2) is not particularly limited, and may be, for example, within the range of 0.1 to 100 μm. In this specification, the term "average particle diameter" refers to the cumulative 50% particle diameter (median diameter; D) on a volume basis measured by a laser diffraction scattering method. ５０ )

[0033] (Curing Agent (Liquid B)) The curing agent (hereinafter also referred to as "Liquid B" or "Second Agent") contains polyisocyanate (B) and inorganic filler (E2), and is preferably a composition substantially composed of only polyisocyanate (B) and inorganic filler (E2). For this reason, this curing agent reacts quickly with hydroxyl groups and amino groups in the base resin. The curing agent is preferably a solvent-free composition that does not substantially contain a liquid medium.

[0034] The polyisocyanate (B) is a compound having two or more isocyanate groups in its molecule. Examples of the polyisocyanate (B) include aliphatic polyisocyanates, aromatic polyisocyanates, and alicyclic polyisocyanates. The aliphatic polyisocyanates include modified aliphatic polyisocyanates.

[0035] Aliphatic polyisocyanates include 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), and 1,10-decamethylene diisocyanate.

[0036] Examples of aromatic polyisocyanates include 4,4'-diphenylmethane diisocyanate (MDI), 2,2'-MDI, 2,4'-MDI, polymeric MDI, 2,4-tolylene diisocyanate (TDI), 2,6-TDI, m-xylylene diisocyanate (XDI), 1,4-phenylene diisocyanate, 4-methoxy-1,3-phenylene diisocyanate, 4-isopropyl-1,3-phenylene diisocyanate, 4-butoxy-1,3-phenylene diisocyanate, 2,4-diisocyanate diphenyl ether, 1,5-naphthalene diisocyanate, and benzidine diisocyanate.

[0037] Examples of the modified aliphatic polyisocyanate include isocyanurates, allophanates, biurets, and adducts of aliphatic polyisocyanates with polyols (such as trimethylolpropane).

[0038] The polyisocyanate (B) is preferably an aliphatic polyisocyanate. The reaction rate of an aliphatic polyisocyanate with the polyol (C) is slower than that of an aromatic polyisocyanate. Therefore, by using an aliphatic polyisocyanate, the usable time of the curable composition can be more sufficiently ensured. It is also preferable to use an aliphatic polyisocyanate and an aromatic polyisocyanate in combination to adjust the usable time.

[0039] Furthermore, the polyisocyanate (B) is more preferably an aliphatic polyisocyanate-modified product, and among the aliphatic polyisocyanate-modified products, a nurate product is particularly preferred. When an aliphatic polyisocyanate-modified product is used, a heat dissipation material that is a three-dimensional cured product can be formed. That is, even when cured under room temperature conditions, a heat dissipation material that is a cured product with improved room temperature adhesion can be formed.

[0040] The curing agent contains a polyisocyanate (B) that has a certain degree of reactivity. Therefore, it is preferable to use an inorganic filler (E2) that has low reactivity with the polyisocyanate (B). For example, a metal oxide or a metal nitride can be used as the inorganic filler (E2) in the curing agent.

[0041] The ratio (NCO / (NH+OH)) of the number of moles of isocyanate groups (NCO) in the curing agent to the total number of moles of amino groups and hydroxyl groups (NH+OH) in the base resin is 0.75 to 2.00, preferably 1.00 to 1.95, and more preferably 1.75 to 1.90. By keeping the value of "NCO / (NH+OH)" within the above range, it is possible to obtain a room-temperature curable composition that can form a heat dissipation material that has excellent adhesion and is resistant to deterioration in adhesion even when heated, while ensuring an appropriate pot life. Note that since the content of amino alcohol (D) is extremely low, the "total number of moles of amino groups and hydroxyl groups in the base resin (NH+OH)" does not include the amino groups and hydroxyl groups of the amino alcohol (D).

[0042] (Other Components) Various additives can be added to the curable composition of the present embodiment as needed. Examples of additives include coupling agents for improving substrate adhesion, ion scavengers for improving insulation reliability during moisture absorption, various dispersants, and leveling agents. The curable composition of the present embodiment is preferably a so-called silicone-free composition that does not substantially contain silicone. The curable composition of the present embodiment can form a heat dissipation material that has excellent adhesion to the surfaces of heating elements, radiators, etc., even without using silicone.

[0043] (Method for producing curable composition) The main agent and the curing agent can be obtained by mixing the above-mentioned components according to a conventional method. Then, the obtained main agent and the curing agent can be appropriately combined to obtain the desired two-component curing type curable composition.

[0044] The viscosity of the base agent and curing agent at 20°C is preferably 100 to 1,000 Pa·s, respectively. If the viscosity is less than 100 Pa·s, the inorganic filler may be more likely to settle, resulting in slightly reduced storage stability. On the other hand, if the viscosity exceeds 1,000 Pa·s, the discharge pressure during coating may become excessively high, which may lead to problems in practical use. Considering storage stability and suitability for coating use, it is more preferable that the viscosity of the base agent and curing agent at 20°C is 200 to 750 Pa·s, respectively. Furthermore, if the viscosity of the base agent at 20°C is 300 to 750 Pa·s and the viscosity of the curing agent at 20°C is 200 to 550 Pa·s, the difference in viscosity between these two agents is relatively small, making them easier to mix, which is particularly preferable in terms of suitability for use.

[0045] <Heat Dissipating Material> One embodiment of the heat dissipating material of the present invention is a cured product obtained by curing the curable composition described above. After mixing the base agent and curing agent constituting the curable composition, the composition is applied to the surface of a heat generating element such as a heat-generating electronic component or a heat sink or other heat dissipating device according to a conventional method. The composition is then cured by holding it at room temperature (approximately 25°C) for a predetermined time without heating, thereby forming the desired heat dissipating material at the desired location. The curing time can be set by appropriately adjusting the content of amino alcohol (D) in the total of polyamine (A), polyol (C), and amino alcohol (D) in the base agent, or the ratio (NCO / (NH+OH)) of the number of moles of isocyanate groups in the curing agent to the total number of moles of amino groups and hydroxyl groups in the base agent (NH+OH). Specifically, the composition can be cured within a holding time of approximately 6 to 48 hours.

[0046] Because the curable composition is a composition that can be cured at room temperature, even when formed on the surface of a heat-sensitive component (such as a CPU), it can be cured without substantially damaging such a component to form the desired heat dissipation material. The thermal conductivity of the heat dissipation material thus formed is typically 2.0 W / (m·K) or more, preferably 2.5 W / (m·K) or more, and more preferably 2.5 to 4.0 W / (m·K). The total filling rate of the inorganic filler (E1) and the inorganic filler (E2) in the heat dissipation material thus formed is preferably 65 to 95 mass%. For this reason, the heat dissipation material of this embodiment is useful as a heat dissipation material (TIM), such as a heat dissipation sheet, disposed between a heat-generating electronic component or other heat source provided inside an electronic device and a heat sink or other heat sink.

[0047] To apply a two-component curing curable composition to a desired location, for example, it is preferable to mix the two components (two liquids) in a flow path and use a two-component mixing static mixer (dispenser) equipped with a nozzle capable of ejecting the liquid mixture of the two components from the tip, and extrude the curable composition from the tip of the nozzle while mixing the two components (base and curing agent). The curable composition described above has a sufficient usable life, and even when the base and curing agent are mixed, it does not immediately harden under room temperature conditions, making it easy to apply to the desired location. In addition, the curable composition described above has good shape retention immediately after application, so it can be accurately applied to the desired location. Furthermore, since the curable composition can be extruded from the tip of a thin nozzle while ensuring a usable life, it can be injected into narrow gaps (gaps) between components, making it highly versatile. In addition, the heat dissipation material of this embodiment has excellent adhesion to various substrate surfaces, does not easily peel off from the substrate surface, etc. even when heated, and has excellent heat-resistant adhesion.

[0048] <Article> One embodiment of the article of the present invention comprises a heat generating element or a heat sink and the above-described heat dissipation material arranged in contact with the heat generating element or the heat sink. Specific examples of the article include Peltier elements, chillers, and vehicle batteries. Examples of the heat generating element include various circuit boards as well as electronic components such as semiconductor devices. Examples of the semiconductor device include power modules such as power semiconductor devices, LEDs, and inverter devices. The semiconductor device is equipped with, for example, semiconductor elements such as insulated gate bipolar transistors, diodes, and IC chips; and various heat generating elements such as resistors and capacitors.

[0049] Even when the heat dissipation material is silicone-free, it has excellent adhesion to the surfaces of heat-generating elements, heat sinks, etc., and has high thermal conductivity. Furthermore, because the heat dissipation material can be formed under room temperature conditions, it is suitable for use on heat-sensitive heat-generating elements such as electronic components. Because the heat dissipation material has excellent heat-resistant adhesion, it will not easily peel off even when placed in contact with the heat-generating element due to the heat of the heat-generating element.

[0050] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are by mass unless otherwise specified.

[0051] <Preparation of Materials> Various materials shown in Tables 1 to 3 were prepared. In Table 2, "OH1," "OH2," and "OH3" are all amorphous polyols having side chains branched from the main chain in their molecules (having a branched structure). "OH1" and "OH2" are castor oil polyols, "OH3" is a polyester diol containing structural units derived from 3-methyl-1,5-pentanediol, and "OH4" is a polyester polyol composed of 1,4-butanediol and adipic acid. Furthermore, "NCO1" and "NCO2" are both aliphatic polyisocyanates (aliphatic polyisocyanate-modified products (nurate products)), and "NCO3" is polymeric MDI.

[0052] In Table 2, "ADD1" to "ADD9" are all commercially available pigment dispersants. Furthermore, in Table 3, the particle shapes of "Fillers 9 to 14" are all spherical, "Filler 7" is irregular, and "Filler 8" is scaly.

[0053]

[0054]

[0055]

[0056] <Preparation of Solution A (Main Agent)> (Solution A A-1) A mixing vessel equipped with a stirrer, reflux condenser, thermometer, nitrogen inlet tube, and manhole was prepared. While the interior of this mixing vessel was purged with nitrogen gas, 50 parts of OH1, 49.99 parts of NH1, and 0.01 parts of ON1 were added. After heating and reducing the pressure to dehydrate, the mixture was stirred at 100°C for 1 hour under a nitrogen stream until homogeneous, thereby obtaining a resin component for the main agent. 100 parts of the obtained resin component for the main agent, 600 parts of filer 2, 300 parts of filer 3, and 100 parts of filer 4 were mixed and stirred for 5 minutes using a stirring mixer (trade name "Awatori Rentaro", manufactured by Thinky Corporation) to obtain Solution A A-1, the main agent.

[0057] (Liquid A-2 to A-45) Liquid A-2 to A-45, which are main components, were obtained in the same manner as Liquid A-1 described above, except that the types and amounts (unit: parts) of each component shown in the upper rows of Tables 4-1 to 4-4 were used. The "filling rate (mass%)" and "filling rate (volume%)" in Tables 4-1 to 4-4 refer to the proportion of inorganic filler in the main component (Liquid A).

[0058]

[0059]

[0060]

[0061]

[0062] <Preparation of Solution B (Curing Agent)> (Solution B B-1) 50 parts of NCO1, 50 parts of NCO2, 550 parts of filer 2, 200 parts of filer 3, and 150 parts of filer 4 were mixed and stirred for 5 minutes using a stirring mixer (trade name "Awatori Rentaro", manufactured by Thinky Corporation) to obtain Solution B B-1, a curing agent.

[0063] (Liquid B-2 to B-45) Curing agents B-2 to B-45 were obtained in the same manner as for the above-mentioned Liquid B-1, except that the types and amounts (unit: parts) of each component shown in the upper rows of Tables 5-1 to 5-4 were used. The "filling rate (mass%)" and "filling rate (volume%)" in Tables 5-1 to 5-4 are the proportions of inorganic filler in the curing agent (Liquid B).

[0064]

[0065]

[0066]

[0067]

[0068] <Preparation of coating material (curable composition)>

[0069] Paints (two-component curing curable compositions) were prepared by combining the types of components A and B shown in Tables 6-1 to 6-4 in a mass ratio of 1:1. The "filling rate (mass%)" and "filling rate (volume%)" in Tables 6-1 to 6-4 represent the proportion of inorganic filler in the entire curable composition (total of components A and B).

[0070] Additionally, a dispenser gun with a trigger for dispensing, a dispenser with two-liquid mixing specifications, and a cylindrical static mixer were prepared. A partition separating the two liquids (two components) was installed inside the dispenser along the flow direction. The dispenser gun was connected to the base of the dispenser in the flow direction, and the base of the static mixer was connected to the tip of the dispenser in the flow direction. When the trigger of the dispenser gun was pulled, the two liquids contained inside the dispenser were each pushed out from the tip of the dispenser and flowed into the static mixer. The two liquids that flowed into the static mixer were mixed uniformly as they flowed, and were then dispensed from the tip of the static mixer.

[0071] <Evaluation of Paints (Curable Compositions)> (Flowability) Each paint (Liquid A and Liquid B) removed from the stirring mixer was placed in a separate container. Liquid A was colored by adding 1% by mass of a blue colorant (product name "Cyanine Blue ZC-7925_T_10_2", manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) that does not affect flowability. The container was tilted or scraped out with a spatula, and Liquid A and Liquid B were poured into the prepared dispenser. A dispenser gun and a static mixer were then connected to the base and tip of the dispenser, respectively. The trigger of the dispenser gun was pulled to eject the paint (curable composition) from the tip of the static mixer, and the flowability of the paint (Liquid A and Liquid B) was evaluated according to the evaluation criteria shown below. Note that, since Liquid A was colored blue, when only Liquid A did not flow, a white paint was ejected; when only Liquid B did not flow, a blue paint was ejected; and when both Liquid A and Liquid B flowed, a light blue paint was ejected. That is, by checking the color of the paint dispensed, it is possible to evaluate the fluidity of each of Liquid A and Liquid B. The results are shown in Tables 6-1 to 6-4. ◎: When pouring into the dispenser, tilting the container 180 degrees allowed for easy flow. ○: Dispensing was possible with just a light pull of the trigger. △: It was difficult to pull the trigger, but dispensing was possible. ×: Dispensing was not possible.

[0072] (Pot life) Each paint (combination of liquid A and liquid B) was placed in a dispenser. After pulling the trigger of the dispenser gun to discharge the paint from the tip of the static mixer, it was left for a specified time, and the time until it hardened at the tip of the static mixer and could no longer be discharged was defined as the pot life. The pot life was then evaluated according to the following evaluation criteria. This dispenser is designed to replace the contents within one hour, and if a large amount is used, it is possible to use up the contents in 30 minutes. The results are shown in Tables 6-1 to 6-4. ◎: Usable for 3 hours or more. ○: Usable for 1 hour or more but less than 3 hours. △: Usable for 30 minutes or more but less than 1 hour. ×: Unusable in less than 30 minutes.

[0073] (Shape Retention) Each paint (combination of liquid A and liquid B) was placed in a dispenser. The trigger of the dispenser gun was pulled to eject the paint from the tip of the static mixer, coating the target area of ​​the SUS plate, and the plate was left to stand for 1 minute at room temperature of 25°C. After standing, the coated product was visually observed, and shape retention was evaluated according to the following evaluation criteria. The results are shown in Tables 6-1 to 6-4. ○: No change (the shape of the coated product was maintained on the target area) ×: Change (the coated product spread from the target area)

[0074] (Normal adhesion) Each paint (combination of liquid A and liquid B) was placed in a dispenser. The trigger of the dispenser gun was pulled to eject the paint from the tip of the static mixer and apply it to a SUS plate, producing a test piece by bonding two SUS plates together. The produced test piece was left at room temperature (25°C) for one day, after which the two SUS plates were peeled off with bare hands and the normal adhesion was evaluated according to the following evaluation criteria. The results are shown in Tables 6-1 to 6-4. ⊚: No peeling occurred. ◯: Interfacial peeling occurred. Δ: Cohesive failure occurred. ×: Uncured (liquid or starch syrup-like).

[0075] (Heat-resistant adhesion) The test pieces prepared for the evaluation of "normal adhesion" above were heat-treated at 120°C for 30 minutes, and the heat-resistant adhesion was evaluated according to the following evaluation criteria. The results are shown in Tables 6-1 to 6-4. ○: No peeling occurred. ×: Peeling occurred.

[0076] (Thermal Conductivity) The thermal conductivity of the cured product obtained by curing the coating material (curable composition) was measured using the hot disk method (ISO 22007-2). Specifically, the coating material was applied to a mold (10 cm x 10 cm) and then pressed at a constant pressure. The coating material was then aged at 40°C for 96 hours to obtain a film-like cured product. The thermal conductivity of the resulting cured product (heat dissipating material) was then measured using a thermal property measuring device (product name "TPS2500S", manufactured by Kyoto Electronics Manufacturing Co., Ltd.). The results are shown in Tables 6-1 to 6-4.

[0077]

[0078]

[0079]

[0080]

[0081] The curable composition of the present invention is also useful as a material for forming thermally conductive materials such as heat-dissipating grease and conductive paint that are placed between a heat-generating body such as an electronic component and a heat sink, radiator, etc. The curable composition of the present invention is also useful as a pressure-sensitive adhesive because it can be easily and cleanly peeled (without leaving any adhesive residue) depending on the inorganic filler blended therein.

Claims

1. A two-component curing type curable composition used to form a heat dissipating material, comprising a combination of a main agent and a curing agent, wherein the main agent contains a polyamine (A), a polyol (C), an aminoalcohol (D), and an inorganic filler (E1), the curing agent contains a polyisocyanate (B) and an inorganic filler (E2), the amine value of the polyamine (A) is 300 mg KOH / g or less, the polyol (C) is an amorphous polyol having a side chain branched from the main chain in its molecule, and the aminoalcohol (D) is a compound having n primary amino groups and m secondary amino groups in its molecule (n and m each independently represent 0 or 1, and n + m = 0 is not satisfied), the content of the aminoalcohol (D) in the main agent is 0.005 to 1 mass% of the total of the polyamine (A), the polyol (C), and the aminoalcohol (D), A curable composition in which the ratio (NCO / (NH+OH)) of the number of moles (NCO) of isocyanate groups in the curing agent to the total number of moles (NH+OH) of amino groups and hydroxyl groups in the base resin is 0.75 to 2.

00.

2. The curable composition according to claim 1, wherein the content of the polyamine (A) in the main component relative to the total of the polyamine (A), the polyol (C), and the amino alcohol (D) is 30 to 90 mass%.

3. The curable composition according to claim 1 or 2, wherein the polyisocyanate (B) is an aliphatic polyisocyanate.

4. The curable composition according to any one of claims 1 to 3, wherein the inorganic filler (E1) and the inorganic filler (E2) are each independently at least one selected from the group consisting of metals, metal oxides, metal nitrides, metal hydroxides, and metal carbonates.

5. The curable composition according to any one of claims 1 to 3, wherein the inorganic filler (E1) and the inorganic filler (E2) are each independently at least one selected from the group consisting of alumina, aluminum nitride, aluminum hydroxide, magnesium oxide, zinc oxide, boron nitride, and magnesium hydroxide.

6. The curable composition according to any one of claims 1 to 5, wherein the filling rate of the inorganic filler (E1) in the base material is 70 to 95 mass %, and the filling rate of the inorganic filler (E2) in the curing agent is 50 to 95 mass %.

7. A heat dissipating material which is a cured product obtained by curing the curable composition according to any one of claims 1 to 6.

8. The heat dissipating material according to claim 7, which has a thermal conductivity of 2.0 W / (m·K) or more.

9. The heat dissipation material according to claim 7 or 8, wherein the total filling rate of the inorganic filler (E1) and the inorganic filler (E2) is 65 to 95 mass %.

10. An article comprising: a heat generating element or a heat sink; and the heat dissipation material according to any one of claims 7 to 9, which is placed in contact with the heat generating element or the heat sink.

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