Curable compositions, heat dissipation materials, and articles

Abstract

The present invention provides a curable composition that exhibits good dispersion of inorganic fillers, is easy to coat, has a suitable pot life, maintains its shape immediately after coating, and, when cured at room temperature, forms a heat dissipation material that has excellent adhesion to the surface of heating elements and heat sinks without the use of silicone, and whose adhesion does not deteriorate even when heated. [Solution] A two-component curable composition used to form a heat dissipation material. The main component contains a polyamine (A), a polyol (C), an amino alcohol (D), and an inorganic filler (E1), and the curing agent contains a polyisocyanate (B) and an inorganic filler (E2), wherein the polyol (C) is an amorphous polyol having side chains, and the amino alcohol (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 possible).

Description

Technical Field

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

Background Art

[0002] With the increase in the density of integrated circuits and the like, the amount of heat generated inside electronic devices tends to increase. Therefore, the development of technologies for efficiently dissipating the heat generated inside electronic components is required. For example, a heat dissipation material (TIM; Thermal Interface Material) such as a heat dissipation sheet having excellent thermal conductivity, which is disposed between a heat generating body such as an electronic component provided inside an electronic device and a radiator such as a heat sink, is known. By using such a heat dissipation material, the fine gap between the surface of the heat generating body and the surface of the radiator can be filled to reduce the contact thermal resistance, and the heat from the heat generating body can be appropriately transferred to the radiator.

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

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

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2005-209955 [Patent Document 2] Special Publication No. 2015-530470 [Patent Document 3] Japanese Patent Publication No. 2020-200454 [Patent Document 4] Japanese Patent Publication No. 2023-508288 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, the conventional compositions proposed in Patent Documents 2 to 4 all require curing under heating conditions, which necessitates securing a heat source in the device production line. This results in a complicated process for placing the heat dissipation material in the desired location, and also presents challenges such as the time required for curing, and is not desirable from the perspective of carbon neutrality.

[0007] Furthermore, because conventional compositions have relatively high fluidity, they tend to spread quickly when applied to target areas such as circuit boards, including SUS plates. As a result, the applied shape may not be maintained, and the coating may spread to areas where it should not be applied, making it difficult to position the heat dissipation material where desired. In addition, cured products such as heat dissipation materials formed using conventional compositions tend to lose adhesion to the target area when heated, and improvement was needed.

[0008] The present invention has been made in view of the problems of the prior art, and aims to provide a curable composition that has good dispersion of inorganic fillers, is easy to coat, has a suitable pot life, has good shape retention immediately after coating, and can form a heat dissipation material that has excellent adhesion to the surface of heating elements and heat sinks, etc., without the use of silicone, and whose adhesion does not deteriorate even when heated, by curing at room temperature. Furthermore, the present invention aims to provide a heat dissipation material which is a cured product obtained by curing the above curable composition, and an article using this heat dissipation material. [Means for solving the problem]

[0009] In other words, the present invention provides the following curable composition. [1] A two-component curable composition comprising a combination of a main component and a curing agent used to form a heat dissipation material, wherein the main component contains a polyamine (A), a polyol (C), an amino alcohol (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 mgKOH / g or less, the polyol (C) is an amorphous polyol having side chains branched from the main chain in its molecule, and the amino alcohol (D) has n 1 A curable composition comprising 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), wherein the content of the amino alcohol (D) in the main component is 0.005 to 1% by mass of the total of the polyamine (A), the polyol (C), and the amino alcohol (D), and the ratio 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 main component (NCO / (NH+OH)) is 0.75 to 2.00. [2] The curable composition according to [1], wherein the content of polyamine (A) in the main component is 30 to 90% by mass of the total of polyamine (A), polyol (C), and amino alcohol (D). [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 [4], wherein the filling rate of the inorganic filler (E1) in the main component is 70 to 95% by mass, and the filling rate of the inorganic filler (E2) in the curing agent is 50 to 95% by mass.

[0010] Furthermore, the present invention provides the following heat dissipation material. [6] A heat dissipation material which is a cured product obtained by curing any of the curable compositions described in [1] to [5] above. [7] The heat dissipation material described in [6] above, wherein the thermal conductivity is 2.0 W / (m·K) or more. [8] The heat dissipation material according to [6] or [7], wherein the total filling rate of the inorganic filler (E1) and the inorganic filler (E2) is 65 to 95% by mass.

[0011] Furthermore, the present invention provides the following articles. [9] An article comprising a heating element and a heat dissipation material according to any one of [6] to [8], which is arranged in contact with the heating element. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a curable composition that has good dispersion of inorganic fillers, is easy to coat, has a suitable pot life, maintains its shape immediately after coating, and, when cured at room temperature, has excellent adhesion to the surface of heating elements and heat sinks without the use of silicone, and can form a heat dissipation material that does not lose adhesion even when heated. Furthermore, according to the present invention, it is possible to provide a heat dissipation material which is a cured product obtained by curing the above curable composition, and an article using this heat dissipation material. [Modes for carrying out the invention]

[0013] <Curable composition> The embodiments of the present invention will be described below, but the present invention is not limited to the embodiments described below. One embodiment of the curable composition of the present invention is a two-component curable composition comprising a combination of a main component and a curing agent, used to form a heat dissipation material. The main component contains a polyamine (A), a polyol (C), an amino alcohol (D), and an inorganic filler (E1), and the curing agent (hereinafter also referred to as "solution B" or "second component") contains a polyisocyanate (B) and an inorganic filler (E2). The amine value of the polyamine (A) is 300 mgKOH / g or less, and the polyol (C) is an amorphous polyol having side chains branched from the main chain in its molecule. The amino alcohol (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 possible). In the main component, the content of amino alcohol (D) relative to the total of polyamine (A), polyol (C), and amino alcohol (D) is 0.005 to 1% by mass. Furthermore, the ratio 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 main component (NCO / (NH+OH)) is 0.75 to 2.00. The details of the curable composition of this embodiment will be described below.

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

[0015] Polyamine (A) is a component that has two or more amino groups in its molecule and reacts with polyisocyanate (B) in the curing agent to form a urea bond. The amino groups in polyamine (A) and amino alcohol (D) react with the isocyanate groups in polyisocyanate (B) at a faster rate than the hydroxyl groups in polyol (C). Therefore, by using polyamine (A) and amino alcohol (D), a urea bond can be formed promptly, and the shape retention and adhesion immediately after coating can be exhibited. At the same time, a heat dissipation material with suppressed decrease in adhesion due to heating can be formed.

[0016] Also, polyamine (A) is a component that also functions as a dispersant for uniformly dispersing inorganic filler (E1) in a good state in the main agent. Therefore, by using polyamine (A), it is possible to increase the filling rate (content) of inorganic filler (E1), and a heat dissipation material can be formed that is excellent in thermal conductivity and has less unevenness in physical properties such as thermal conductivity and adhesion.

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

[0018] The amine value of the polyamine (A) is 300 mg KOH / g or less, preferably 20 to 250 mg KOH / g, more preferably 70 to 200 mg KOH / g. Since the polyamine (A) with an amine value exceeding 300 mg KOH / g has small molecules, the reaction rate tends to increase. Therefore, heat is easily generated during curing, and the pot life becomes short.

[0019] Two or more polyamines (A) can be contained in the main agent. The "amine value of the polyamine (A)" in the case where the main agent contains two or more polyamines (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 that has two or more hydroxyl groups in its molecule and 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 with the isocyanate groups in the polyisocyanate (B) at a slower rate than the amino groups in the polyamine (A). Therefore, by using the polyamine (A), the polyol (C), and the amino alcohol (D) in combination, after the urea bond is rapidly formed and the initial physical properties are exhibited, the remaining polyisocyanate (B) reacts gently with the polyol (C) and the amino alcohol (D) to form a urethane bond. Thus, it is possible to form a heat-dissipating material that has excellent adhesion while ensuring appropriate fluidity and sufficient pot life and suppressing a decrease in adhesion due to heating.

[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 to improve the dispersibility of the inorganic filler. As a result, a curable composition with a relatively low viscosity and easier to use as a paint can be obtained. On the other hand, when using a crystalline polyol having no side chain, an amorphous polyol having no side chain, or a crystalline polyol having a side chain, the fluidity of the main agent (liquid A) decreases, and it becomes difficult to ensure a sufficient pot life.

[0022] Examples of amorphous polyols having branched side chains in their molecules 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 diols containing constituent units derived from branched alkyl chain diols 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 diols; polyether diols such as polypropylene glycol; and polybutadiene polyols. Castor oil polyols are particularly preferred because they have relatively low viscosity and long side chains in their molecules.

[0023] The hydroxyl value of polyol(C) is not particularly limited, and is usually 50 to 1,500 mgKOH / g. From the viewpoint of adjusting the reaction rate and pot life, it is preferably 80 to 1,250 mgKOH / g, and more preferably 100 to 600 mgKOH / g. If the hydroxyl value of 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 polyol(C) is too high, the reaction rate at room temperature tends to be too fast, and the pot life may be shortened.

[0024] Amino alcohol (D) is a compound having n primary amino groups (-NH2) and m secondary amino groups (-NH-) in its molecule (n and m independently represent 0 or 1, and n+m=0 is never the case). Like polyamine (A), it is a component that reacts with polyisocyanate (B) in the curing agent to form urea bonds. By using such amino alcohol (D) in combination with polyamine (A), as described above, urea bonds can be rapidly formed, enabling the formation of shape retention and adhesion immediately after coating, as well as creating a heat dissipation material with suppressed deterioration of adhesion due to heating. On the other hand, if an amino alcohol having two or more primary amino groups (-NH2) in its molecule, or an amino alcohol having only tertiary amino groups (n+m=0) in its molecule is used, it becomes difficult to obtain the desired properties (adhesion, shape retention, and appropriate 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 (however, the number of primary amino groups (n) is 0). Using such an amino alcohol (D) allows for a more sufficient pot life. If faster curing is desired, the amino alcohol (D) is preferably a compound having one primary amino group in its molecule (however, the number of secondary amino groups (m) is 0 or 1).

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

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

[0028] In the main component, the content of polyamine (A) as a percentage of the total of polyamine (A), polyol (C), and amino alcohol (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) as a percentage of the total of polyamine (A), polyol (C), and amino alcohol (D) is less than 30% by mass, curing may be slightly more difficult or the curing time may be slightly longer under room temperature (25°C) conditions. On the other hand, if the content of polyamine (A) as a percentage of the total of polyamine (A), polyol (C), and amino alcohol (D) is more than 90% by mass, the curing speed may be slightly faster and the pot life may be slightly shorter.

[0029] The inorganic filler (E1) in the main component and the inorganic filler (E2) in the curing agent are both inorganic components that have thermal conductivity. In other words, both the main component and the curing agent constituting the curing composition of this embodiment contain inorganic fillers. By including inorganic fillers in both the main component and the curing agent, the main component and the curing agent can be mixed uniformly, and a heat dissipation material can be formed, which is a cured product in which the inorganic fillers are uniformly dispersed.

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

[0031] Inorganic filler (E1) and 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 include gold, silver, copper, aluminum, 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 individually or in combination of two or more.

[0032] Examples of particle shapes for inorganic fillers (E1) and inorganic fillers (E2) include spherical, needle-shaped, flake-shaped, dendritic, fibrous, and amorphous forms. Furthermore, the average particle diameter of inorganic fillers (E1) and inorganic fillers (E2) is not particularly limited and may be within the range of 0.1 to 100 μm, for example. In this specification, "average particle diameter" refers to the volume-based cumulative 50% particle diameter (median diameter; D) measured by laser diffraction scattering. 50 )

[0033] (Hardening agent (Part 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 solely of polyisocyanate (B) and inorganic filler (E2). Therefore, this curing agent reacts rapidly with the hydroxyl groups and amino groups in the main component. The curing agent is preferably a solvent-free composition that substantially does not contain a liquid medium.

[0034] Polyisocyanates (B) are compounds having two or more isocyanate groups in their molecule. Examples of polyisocyanates (B) include aliphatic polyisocyanates, aromatic polyisocyanates, and alicyclic polyisocyanates. Note that aliphatic polyisocyanates include modified aliphatic polyisocyanates.

[0035] Examples of 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-phenylenediisocyanate, 4-methoxy-1,3-phenylenediisocyanate, 4-isopropyl-1,3-phenylenediisocyanate, 4-butoxy-1,3-phenylenediisocyanate, 2,4-diisocyanate diphenyl ether, 1,5-naphthalenediisocyanate, and benzidine diisocyanate.

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

[0038] The polyisocyanate (B) is preferably an aliphatic polyisocyanate. Aliphatic polyisocyanates react more slowly with polyol (C) than aromatic polyisocyanates. Therefore, using an aliphatic polyisocyanate allows for a more sufficient pot life of the curable composition. It is also preferable to use both aliphatic and aromatic polyisocyanates in combination to adjust the pot life.

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

[0040] The curing agent contains polyisocyanate (B), which has a certain degree of reactivity. Therefore, it is preferable to use an inorganic filler (E2) that has low reactivity with polyisocyanate (B). For example, metal oxides or metal nitrides can be used as the inorganic filler (E2) in the curing agent, and metal hydroxides or metal carbonates can be used as the inorganic filler (E1) in the main component.

[0041] The ratio 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 main component (NCO / (NH+OH)) is 0.75 to 2.00, preferably 1.00 to 1.95, and more preferably 1.75 to 1.90. By setting the value of "NCO / (NH+OH)" within the above range, it is possible to create a room-temperature curable composition that has excellent adhesion while ensuring a suitable pot life and forming a heat dissipation material whose adhesion does not deteriorate easily even when heated. Note that since the content of amino alcohol (D) is extremely small, the "total number of moles of amino groups and hydroxyl groups (NH+OH) in the main component" does not include the amino and hydroxyl groups of amino alcohol (D).

[0042] (Other ingredients) Various additives may be added to the curable composition of this embodiment as needed. Examples of additives include coupling agents to improve adhesion to the substrate, ion scavenging agents to improve insulation reliability when moisture is absorbed, various dispersants, and leveling agents. Preferably, the curable composition of this embodiment is a so-called silicone-free composition that does not substantially contain silicone. The curable composition of this embodiment can form a heat dissipation material with excellent adhesion to the surface of a heating element or heat sink, etc., even without using silicone.

[0043] (Method for manufacturing curable compositions) By mixing the above-mentioned components according to conventional methods, a main component and a curing agent can be obtained. Then, by appropriately combining the obtained main component and curing agent, a two-component curing type curable composition can be obtained.

[0044] The viscosity of the main component and the hardener 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 settle easily, and the storage stability may be slightly reduced. On the other hand, if the viscosity is greater than 1,000 Pa·s, the discharge pressure during coating may become excessively high, which may cause problems in actual use. Considering storage stability and suitability for coating use, it is even more preferable that the viscosity of the main component and the hardener at 20°C is 200 to 750 Pa·s, respectively. Furthermore, if the viscosity of the main component at 20°C is 300 to 750 Pa·s and the viscosity of the hardener at 20°C is 200 to 550 Pa·s, the viscosity difference between these two components is relatively small, making them easy to mix, which is particularly preferable in terms of suitability for use.

[0045] <Heat dissipation material> One embodiment of the heat dissipation material of the present invention is a cured product obtained by curing the aforementioned curable composition. After mixing the main component and curing agent constituting the curable composition, the mixture is applied to the surface of a heat-generating element such as a heat-generating electronic component or a heat sink such as a heat dissipation device according to a conventional method. Subsequently, without the need for heating, the mixture is cured by holding it at room temperature (approximately 25°C) for a predetermined time, thereby forming the desired heat dissipation 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 main component, and the ratio 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 main component (NCO / (NH+OH)). Specifically, curing can be achieved with a holding time of approximately 6 to 48 hours.

[0046] Since 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, thereby forming the desired heat dissipation material. The thermal conductivity of the heat dissipation material formed in this way is usually 2.0 W / (m·K) or higher, preferably 2.5 W / (m·K) or higher, and more preferably 2.5 to 4.0 W / (m·K). Furthermore, the total filling rate of inorganic filler (E1) and inorganic filler (E2) in the heat dissipation material formed in this way is preferably 65 to 95% by mass. For this reason, the heat dissipation material of this embodiment is useful, for example, as a heat dissipation material (TIM) such as a heat dissipation sheet placed between a heat-generating element such as a heat-generating electronic component installed inside an electronic device and a heat sink or other heat dissipation device.

[0047] To coat a two-component curable composition to a desired location, it is preferable to use a static mixer (dispenser) for two-component mixing, which includes a nozzle capable of dispensing the liquid mixture of the two components (main component and hardener) from its tip, while mixing the two components (main component and hardener) and extruding the curable composition from the tip of the nozzle. The above-mentioned curable composition has a sufficient pot life and does not harden immediately at room temperature even after mixing the main component and hardener, allowing for easy coating to the desired location. Furthermore, the above-mentioned curable composition has good shape retention immediately after coating, allowing for accurate coating to the desired location. Moreover, since the curable composition can be extruded from the tip of a narrow nozzle while ensuring a sufficient pot life, it can be injected into narrow gaps between components, making it highly versatile. In addition, the heat dissipation material of this embodiment has excellent adhesion to various substrate surfaces, and does not easily peel off from the substrate surface even when heated, demonstrating excellent heat-resistant adhesion.

[0048] <Goods> One embodiment of the article of the present invention comprises a heating element and the aforementioned heat dissipation material arranged in contact with the heating element. Examples of heating elements include various circuit boards and electronic components such as semiconductor devices. Examples of semiconductor devices include power semiconductor devices, LEDs, and power modules such as inverter devices. The semiconductor device may be equipped with semiconductor elements such as insulated-gate bipolar transistors, diodes, and IC chips; and various heating elements such as resistors and capacitors.

[0049] Even when silicone-free, the heat dissipation material exhibits excellent adhesion to the surface of heat-generating elements and heat sinks, and also possesses high thermal conductivity. Furthermore, since the heat dissipation material can be formed under room temperature conditions, it can be suitably applied to heat-generating elements such as heat-sensitive electronic components. Due to its excellent heat-resistant adhesion, the heat dissipation material will not easily peel off even when placed in contact with a heat-generating element, despite the heat from the element. [Examples]

[0050] Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are based on 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 (having a branched structure) in their molecules. "OH1" and "OH2" are castor oil polyols, "OH3" is a polyester diol containing a structural unit derived from 3-methyl-1,5-pentanediol, and "OH4" is a polyester polyol composed of 1,4-butanediol and adipic acid. Also, "NCO1" and "NCO2" are both aliphatic polyisocyanates (aliphatic polyisocyanate modified products (nurate forms)), and "NCO3" is polymeric MDI.

[0052] In Table 2, "ADD1" to "ADD9" are all commercially available as pigment dispersants. Further, in Table 3, the particle shapes of "filler9 to 14" are all spherical, "filler7" is irregular, and "filler8" is flaky.

[0053] TIFF2026046019000001.tif84170

[0054] TIFF2026046019000002.tif136170

[0055] TIFF2026046019000003.tif166170

[0056] <Preparation of Liquid A (Main Agent)> (Liquid A - 1) A mixing container equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen injection tube, and a manhole was prepared. While replacing the inside of this mixing container with nitrogen gas, 50 parts of OH1, 49.99 parts of NH1, and 0.01 parts of ON1 were put in. After heating under reduced pressure for dehydration treatment, it was stirred at 100 °C for 1 hour under a nitrogen stream to obtain a resin component for the main agent. 100 parts of the obtained resin component for the main agent, 600 parts of filer2, 300 parts of filer3, and 100 parts of filer4 were mixed and stirred for 5 minutes using a stirring mixer (trade name "Awatori Rentaro", manufactured by Shinki Co., Ltd.) to obtain A liquid A-1, which is the main agent.

[0057] (Liquid A A-2 to A-45) Except for using the types and amounts (unit: parts) of each component shown in the upper rows of Tables 4-1 to 4-4, liquid A A-2 to A-45, which are the main agents, were obtained in the same manner as in the case of liquid A A-1 described above. The "filling rate (mass%)" and "filling rate (volume%)" in Tables 4-1 to 4-4 are the ratios of the inorganic filler (filer) to the main agent (liquid A).

[0058] TIFF2026046019000004.tif153170

[0059] TIFF2026046019000005.tif180170

[0060] TIFF2026046019000006.tif183170

[0061] TIFF2026046019000007.tif196170

[0062] <Preparation of liquid B (hardener)> (Liquid B B-1) 50 parts of NCO1, 50 parts of NCO2, 550 parts of filer2, 200 parts of filer3, and 150 parts of filer4 were mixed and stirred for 5 minutes using a stirring mixer (trade name "Awatori Rentaro", manufactured by Shinki Co., Ltd.) to obtain liquid B B-1, which is the hardener.

[0063] (Liquid B B-2 to B-45) Except for using the types and quantities (in parts) of each component shown in the upper row of Tables 5-1 to 5-4, the curing agents B-2 to B-45 were obtained in the same manner as in the case of B-1 described above. The "filling rate (mass%)" and "filling rate (volume%)" in Tables 5-1 to 5-4 represent the proportion of inorganic filler to the curing agent (B-liquid).

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[0068] <Preparation of paint (curable composition)>

[0069] Paints (two-component curable compositions) were prepared by combining the types of liquid A and liquid B shown in Tables 6-1 to 6-4 in a 1:1 mass ratio. 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 liquid A and liquid B).

[0070] Furthermore, a dispenser gun with a trigger for dispensing, a dispenser designed for mixing two liquids, and a cylindrical static mixer were prepared. Inside the dispenser, a partition wall is provided to separate the two liquids (two components) along the direction of flow. The dispenser gun is connected to the base of the dispenser in the direction of flow, and the base of the static mixer is connected to the tip in the direction of flow. When the trigger of the dispenser gun is pulled, the two liquids contained inside the dispenser are pushed out from the tip of the dispenser and flow into the static mixer. The two liquids that flow into the static mixer are mixed uniformly while flowing, and the mixture is discharged from the tip of the static mixer.

[0071] <Evaluation of paints (curable compositions)> (Liquidity) Each paint (liquid A and liquid B) was removed from the mixing mixer and placed into separate containers. Liquid A was colored by adding 1% by mass of a blue colorant (product name "Cyanine Blue ZC-7925_T_10_2", manufactured by Dainichi Seika Kogyo Co., Ltd.), which does not affect the fluidity. Liquids A and B were poured into the prepared dispensers by tilting the containers or scraping them out with a spatula. A dispenser gun and a static mixer were then connected to the base and tip of the dispensers, respectively. The trigger of the dispenser gun was pulled to dispense the paint (curable composition) from the tip of the static mixer, and the fluidity of the paints (liquid A and liquid B) was evaluated according to the evaluation criteria shown below. Since liquid A is colored blue, if only liquid A does not flow, white paint will be dispensed; if only liquid B does not flow, blue paint will be dispensed; and if both liquids A and B flow, light blue paint will be dispensed. In other words, the fluidity of each liquid, A and B, can be evaluated by checking the color of the dispensed paint. The results are shown in Tables 6-1 to 6-4. ◎: When pouring into the dispenser, tilting the container 180° made it easy to flow. ○: Dispensing was easy with just a light pull of the trigger. △: The trigger was heavy to pull, but it was able to dispense. ×: Discharge was impossible.

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

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

[0074] (Normal close contact) Each paint (combination of liquid A and liquid B) was placed in a separate dispenser. The trigger of the dispenser gun was pulled to dispense the paint from the tip of the static mixer and coat the SUS plate, and a test specimen was prepared by bonding two SUS plates together. After leaving the prepared test specimen at room temperature (25°C) for one day, the two SUS plates were separated by hand, and the normal adhesion was evaluated according to the evaluation criteria shown below. The results are shown in Tables 6-1 to 6-4. ◎: Did not peel off. ○: Interfacial delamination occurred. △: Cohesive failure occurred. ×: It was uncured (liquid or syrup-like).

[0075] (Heat-resistant adhesion) The test specimens prepared for the "normal adhesion" evaluation described above were heat-treated at 120°C for 30 minutes, and the heat-resistant adhesion was evaluated according to the evaluation criteria shown below. The results are shown in Tables 6-1 to 6-4. ○: Did not peel off. ×: Peeled off.

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

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[0080] TIFF2026046019000015.tif116170 [Industrial applicability]

[0081] The curable composition of the present invention is useful as a material for forming heat dissipation materials such as heat dissipation sheets that are placed between a heat-generating element such as an electronic component and a heat sink or other heat exchanger.

Claims

1. A two-component curable composition comprising a combination of a main component and a curing agent, used to form a heat dissipation material, The main component contains a polyamine (A), a polyol (C), an amino alcohol (D), and an inorganic filler (E1). The curing agent contains polyisocyanate (B) and 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 side chains branched from the main chain within its molecule. The amino alcohol (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 possible), In the main component, the content of the amino alcohol (D) relative to the total of the polyamine (A), the polyol (C), and the amino alcohol (D) is 0.005 to 1% by mass. A curable composition in which the ratio 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 main component (NCO / (NH+OH)) is 0.75 to 2.

00.

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

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

4. The curable composition according to claim 1, 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 filling rate of the inorganic filler (E1) in the main component is 70 to 95% by mass. The curable composition according to claim 1, wherein the filling rate of the inorganic filler (E2) in the curing agent is 50 to 95% by mass.

6. A heat dissipation material which is a cured product obtained by curing a curable composition according to any one of claims 1 to 5.

7. The heat dissipation material according to claim 6, wherein the thermal conductivity is 2.0 W / (m·K) or higher.

8. The heat dissipation material according to claim 6, wherein the total filling rate of the inorganic filler (E1) and the inorganic filler (E2) is 65 to 95% by mass.

9. Heating element and An article comprising a heat dissipation material according to claim 6, which is arranged in contact with the heat generating element.

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