Curable composition, heat-dissipating material, and article

Abstract

To provide a curable composition that ensures an appropriate pot life, has a good dispersion state of inorganic fillers, exhibits excellent adhesion to surfaces of a heating element, a heat dissipator, and the like even without using silicone, can cure under room temperature conditions, and can form a heat-dissipating material that can be easily peeled off by heating.SOLUTION: Provided is a two-component curable composition used for forming a heat-dissipating material, the composition including a combination of a main agent and a curing agent. The main agent comprises a polyamine (A), a diol (C), and an inorganic filler (D1), and the curing agent comprises a polyisocyanate (B) and an inorganic filler (D2). In the main agent, the content of the polyamine (A) in the total of the polyamine (A) and the diol (C) is 50 to 90 mass%. The ratio 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 agent is 0.75 to 2.50.SELECTED DRAWING: None

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 heat radiator such as a heat sink, is known. By using such a heat dissipation material, it is possible to fill the fine gaps between the surfaces of the heat generating body and the heat radiator to reduce the contact thermal resistance and appropriately transfer the heat from the heat generating body to the heat radiator.

[0003] Hitherto, 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). Further, 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 Application Laid-Open No. 2005-209955 Patent Document 2 Japanese Patent Application Laid-Open No. 2015-530470 Patent Document 3 Japanese Patent Application Laid-Open No. 2020-200454 Patent Document 4 Japanese Patent Application Laid-Open No. 2023-508288 Summary of the Invention Problems to be Solved by the Invention

[0006] However, since the compositions and the like proposed in Patent Documents 2 to 4 all require curing under heating conditions, it is necessary to secure a heat source in the production line of the device. For this reason, the process for arranging the heat dissipation material at a desired location becomes complicated, and there are problems such as time-consuming curing. Moreover, it is not favorable for the effort towards carbon neutrality. Further, it is difficult to peel off from a heating element or the like after curing, and it is difficult to respond to needs such as separate disposal after use, and the repairability and recyclability are not necessarily good.

[0007] The present invention has been made in view of such problems of the prior art. The object of the present invention is to ensure an appropriate pot life, have a good dispersion state of the inorganic filler, have excellent adhesion to the surface of a heating element, a radiator, etc. even without using silicone, be curable under room temperature conditions, and be able to form a heat dissipation material that can be easily peeled off by heating. Another object of the present invention is to provide a heat dissipation material which is a cured product obtained by curing the above-described curable composition, and an article using this heat dissipation material. Means for Solving the Problems

[0008] That is, according to the present invention, there is provided a curable composition shown below. [1] A two-component curable composition containing a combination of a main agent and a curing agent used for forming a heat-dissipating material, wherein the main agent contains a polyamine (A), a diol (C), and an inorganic filler (D1), the curing agent contains a polyisocyanate (B) and an inorganic filler (D2), in the main agent, the content of the polyamine (A) in the total of the polyamine (A) and the diol (C) is 50 to 90% by mass, and the value of 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 main agent is 0.75 to 2.50. [2] The curable composition according to [1], wherein the amine value of the polyamine (A) is 300 mgKOH / g or less. [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 (D1) and the inorganic filler (D2) 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 (D1) in the main agent is 70 to 95% by mass, and the filling rate of the inorganic filler (D2) in the curing agent is 50 to 95% by mass.

[0009] Further, according to the present invention, a heat-dissipating material shown below is provided. [6] A heat-dissipating material which is a cured product obtained by curing the curable composition according to any one of [1] to [5]. [7] The heat-dissipating material according to [6], wherein the thermal conductivity is 2.0 W / (m·K) or more. [8] The heat-dissipating material according to [6] or [7], wherein the total filling rate of the inorganic filler (D1) and the inorganic filler (D2) is 65 to 95% by mass.

[0010] Furthermore, according to the present invention, an article shown below is provided. An article comprising a heating element and a heat dissipating material according to any one of [6] to [8] disposed in contact with the heating element.

Advantages of the Invention

[0011] According to the present invention, an appropriate service life is ensured, the dispersion state of the inorganic filler is good, and the adhesion to the surface of a heating element, a radiator, etc. is excellent even without using silicone, it can be cured under room temperature conditions, and a curable composition capable of forming a heat dissipating material that can be easily peeled off by heating can be provided. Further, according to the present invention, a heat dissipating material which is a cured product obtained by curing the above curable composition, and an article using this heat dissipating material can be provided.

Embodiments for Carrying Out the Invention

[0012] <Curable Composition> Hereinafter, embodiments of the present invention will be described, 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 containing a combination of a main agent and a curing agent used for forming a heat dissipating material. The main agent contains a polyamine (A), a diol (C), and an inorganic filler (D1), and the curing agent contains a polyisocyanate (B) and an inorganic filler (D2). In the main agent, the content of the polyamine (A) in the total of the polyamine (A) and the diol (C) is 50 to 90% by mass. And the value of 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 main agent is 0.75 to 2.50. Hereinafter, the details of the curable composition of this embodiment will be described.

[0013] (Main Agent) The curable composition of this embodiment is a two-component curable composition containing a combination of a main agent and a curing agent, and is a composition set of the type that is cured under predetermined conditions after mixing the two agents (two components). The main agent (first agent) contains a polyamine (A), a diol (C), and an inorganic filler (D1), and is preferably a composition substantially composed of only the polyamine (A), the diol (C), and the inorganic filler (D1). The main agent is preferably a solvent-free composition that substantially does not contain a liquid medium.

[0014] The polyamine (A) is a component that has two or more amino groups in its molecule and reacts with the polyisocyanate (B) in the curing agent to form a urea bond. The polyamine (A) has a faster reaction rate with the polyisocyanate (B) than the diol (C) similarly contained in the main agent. Therefore, by using the polyamine (A), a urea bond can be formed promptly, and the initial physical properties (normal adhesion) can be expressed.

[0015] In addition, the polyamine (A) is also a component that functions as a dispersant for uniformly dispersing the inorganic filler (D1) in a good state in the main agent. Therefore, by using the polyamine (A), it is possible to increase the filling rate (content) of the inorganic filler (D1), and it is possible to form a heat dissipation material that is excellent in thermal conductivity and has less unevenness in physical properties such as thermal conductivity and adhesion.

[0016] 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. On the other hand, the polyamine (A) that can also function as a dispersant is incorporated into the molecule 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 main agent that substantially does not contain a dispersant (excluding polyamine (A)) for dispersing the inorganic filler (D1), 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.

[0017] The amine value of the polyamine (A) is preferably 300 mg KOH / g or less, more preferably 20 to 250 mg KOH / g, and particularly preferably 70 to 200 mg KOH / g. When the amine value of the polyamine (A) exceeds 300 mg KOH / g, since the molecules are small, the reaction rate tends to increase. For this reason, heat may be easily generated during curing, and the pot life may be slightly shortened.

[0018] 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.

[0019] The diol (C) is a component that has two hydroxyl groups in its molecule and reacts with the polyisocyanate (B) in the curing agent to form a urethane bond. The diol (C) has a slower reaction rate with the polyisocyanate (B) than the polyamine (A) similarly contained in the main agent. For this reason, by using the polyamine (A) and the diol (C) in combination, after the urea bond is rapidly formed and the initial physical properties are exhibited, the remaining polyisocyanate (B) and the diol (C) react gently to form a urethane bond, so that a heat dissipation material excellent in adhesion can be formed while ensuring a sufficient pot life.

[0020] The hydroxyl value of the diol (C) is not particularly limited and is usually 50 to 1,500 mg KOH / g, and preferably 100 to 1,250 mg KOH / g from the viewpoint of adjusting the reaction rate and the pot life. If the hydroxyl value of the diol (C) is too low, the reaction rate under room temperature conditions tends to be slow, and it may be difficult to ensure normal adhesion. On the other hand, if the hydroxyl value of the diol (C) is too high, the reaction rate under room temperature conditions tends to be too fast, and the pot life may be shortened.

[0021] Examples of the diol (C) include polycarbonate diol and polyester diol. As the polycarbonate diol, for example, a reaction product of a dialkyl carbonate such as dimethyl carbonate and a diol compound having two hydroxyl groups in the molecule can be used. Also, a commercially available polycarbonate diol can be used. Examples of the diol compound include linear or branched diols having 2 to 10 carbon atoms.

[0022] Examples of the diol compound include aliphatic diols and alicyclic diols. Examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, and 2-methyl-1,8-octanediol. Examples of the alicyclic diol include 1,4-cyclohexanedimethanol. From the viewpoint of further improving the flexibility of the polyurethane resin, aliphatic diols are preferred, and 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and neopentyl glycol are more preferred.

[0023] Examples of the polyester diol include those obtained by polycondensing at least one of aliphatic dicarboxylic acids and aromatic dicarboxylic acids with low molecular weight glycols. Examples of the aliphatic dicarboxylic acids include succinic acid, adipic acid, sebacic acid, glutaric acid, and azelaic acid. Examples of the aromatic dicarboxylic acid include isophthalic acid and terephthalic acid. Examples of the low molecular weight glycols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 3-methylpentanediol, 1,6-hexamethylene glycol, neopentyl glycol, and 1,4-bishydroxymethylcyclohexane.

[0024] As the diol (C), polymer diols other than the above-mentioned polycarbonate diol and polyester diol can also be used. Examples of the polymer diols other than polycarbonate diol and the like include polyether-based diols, polylactone-based diols, dimer diols, and other polymer diols. Further, short-chain diols having a molecular weight of 400 or less can also be used in combination.

[0025] Among them, as the diol (C), it is preferable to use a diol having a side chain in its molecular structure. Examples of the diol having a side chain in its molecular structure 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 structural units derived from diols having a branched alkyl chain 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; polybutadiene polyols and the like. When a diol 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 having a relatively low viscosity and being more easily used as a paint can be obtained.

[0026] In the main agent, the content of the polyamine (A) in the total of the polyamine (A) and the diol (C) is 50 to 90% by mass, preferably 60 to 85% by mass, and more preferably 70 to 80% by mass. When the content of the polyamine (A) in the total of the polyamine (A) and the diol (C) is less than 50% by mass, it becomes difficult to cure under room temperature (25°C) conditions, or the curing time becomes too long. On the other hand, when the content of the polyamine (A) in the total of the polyamine (A) and the diol (C) exceeds 90% by mass, the curing rate becomes too fast and the pot life becomes insufficient.

[0027] The inorganic filler (D1) in the main agent and the inorganic filler (D2) in the curing agent are both inorganic components having thermal conductivity. That is, both the main agent and the curing agent constituting the curable composition of the present embodiment contain an inorganic filler. By containing an inorganic filler in both the main agent and the curing agent, the main agent and the curing agent can be uniformly mixed, and a heat dissipation material that is a cured product in which the inorganic filler is uniformly dispersed can be formed.

[0028] The inorganic filler (D1) in the main agent and the inorganic filler (D2) in the curing agent may be of the same type or different types. The main agent contains a polyamine (A) that can also function as a dispersant. Therefore, a relatively large amount of the inorganic filler (D1) can be filled (contained) in the main agent. Specifically, the filling rate of the inorganic filler (D1) in the main agent is preferably 70 to 95% by mass, more preferably 80 to 95% by mass. The filling rate of the inorganic filler (D2) in the curing agent is preferably 50 to 95% by mass, more preferably 85 to 90% by mass.

[0029] The inorganic filler (D1) and the inorganic filler (D2) are each preferably at least one selected independently from the group consisting of metals, metal oxides, metal nitrides, metal hydroxides, and metal carbonates. Examples of the metal include gold, silver, copper, aluminum, and alloys containing these. Examples of the metal oxide include alumina, calcium oxide, magnesium oxide, zinc oxide, beryllia, titanium oxide, and silica. Examples of the metal nitride include aluminum nitride, boron nitride, carbon nitride, and silicon nitride. Examples of the metal hydroxide include aluminum hydroxide, magnesium hydroxide, and calcium hydroxide. Examples of the metal carbonate include calcium carbonate, magnesium carbonate, and hydrotalcite. The inorganic filler can be used alone or in combination of two or more.

[0030] Examples of the particle shape of the inorganic filler (D1) and the inorganic filler (D2) include spherical, needle-like, flake-like, dendritic, fibrous, and amorphous. Also, the average particle diameter of the inorganic filler (D1) and the inorganic filler (D2) is not particularly limited, and for example, it may be in the range of 0.1 to 100 μm. The "average particle diameter" in this specification is the volume-based cumulative 50% particle diameter (median diameter; D 50 ) measured by the laser diffraction scattering method.

[0031] (Curing agent) The curing agent (second agent) contains a polyisocyanate (B) and an inorganic filler (D2), and is preferably a composition substantially composed of only the polyisocyanate (B) and the inorganic filler (D2). Therefore, this curing agent reacts rapidly with the hydroxyl groups and amino groups in the main agent. The curing agent is preferably a solvent-free composition that substantially does not contain a liquid medium.

[0032] 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. Note that the aliphatic polyisocyanates include modified aliphatic polyisocyanates.

[0033] Examples of the aliphatic polyisocyanate include 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), and 1,10-decamethylene diisocyanate.

[0034] Examples of the aromatic polyisocyanate include 4,4'-diphenylmethane diisocyanate (MDI), 2,2'-MDI, 2,4'-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.

[0035] Examples of the modified aliphatic polyisocyanate include isocyanurate, allophanate, biuret, and adducts with polyols (such as trimethylolpropane) of aliphatic polyisocyanates.

[0036] The polyisocyanate (B) is preferably an aliphatic polyisocyanate. The aliphatic polyisocyanate has a slower reaction rate with the diol (C) compared to the aromatic polyisocyanate. Therefore, by using the aliphatic polyisocyanate, the pot life of the curable composition can be ensured more sufficiently. In addition, it is also preferable to use the aliphatic polyisocyanate and the aromatic polyisocyanate in combination to adjust the pot life.

[0037] Furthermore, the polyisocyanate (B) is more preferably an aliphatic polyisocyanate modified product, and particularly preferably a nurate among the aliphatic polyisocyanate modified products. When using the aliphatic polyisocyanate modified product, a heat dissipation material which is a three-dimensional cured product can be formed. That is, even when cured under room temperature conditions, a heat dissipation material which is a cured product with improved normal temperature adhesiveness can be formed.

[0038] In addition, the curing agent contains a polyisocyanate (B) with a certain degree of high reactivity. Therefore, it is preferable to use an inorganic filler (D2) with low reactivity with the polyisocyanate (B). For example, metal oxides, metal nitrides, etc. can be used as the inorganic filler (D2) in the curing agent, and metal hydroxides, metal carbonates, etc. can be used as the inorganic filler (D1) in the main agent.

[0039] 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 main agent is 0.75 to 2.50, 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, a room temperature curable curable composition can be obtained which can ensure an appropriate pot life, has excellent adhesiveness, and can form a heat dissipation material that can be peeled off by heating.

[0040] (Other components) Various additives can be added to the curable composition of the present embodiment as needed. Examples of the additives include a coupling agent for enhancing substrate adhesion, an ion scavenger for enhancing insulation reliability during moisture absorption, a leveling agent, and the like. Note that the curable composition of the present embodiment is preferably a so-called silicone-free composition that substantially does not contain silicone. The curable composition of the present embodiment can form a heat dissipation material having excellent adhesion to the surface of a heating element, a radiator, or the like without using silicone.

[0041] (Method for producing curable composition) By mixing the above-described components according to a conventional method, a main agent and a curing agent can be obtained respectively. Then, by appropriately combining the obtained main agent and curing agent, a target two-component curable composition can be obtained.

[0042] The viscosities of the main agent and the curing agent at 20°C are preferably 100 to 1,000 Pa·s, respectively. If the viscosity is less than 100 Pa·s, the inorganic filler may easily settle, and the storage stability may be slightly reduced. On the other hand, if the viscosity exceeds 1,000 Pa·s, the discharge pressure during coating may become excessively high, and problems may easily occur in actual use. Considering storage stability, coating workability, etc., the viscosities of the main agent and the curing agent at 20°C are more preferably 200 to 750 Pa·s, respectively. Further, when the viscosity of the main 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 viscosity difference between these two components is relatively small, and they are easily mixed, which is particularly preferable in terms of workability.

[0043] (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 agent and the curing agent constituting the curable composition, it is applied to the surface of a heat generating body such as a heat generating electronic component or a radiator such as a heat sink according to a conventional method. Then, without the need for heating, it is cured by holding it for a predetermined time under room temperature (about 25°C) conditions, and the target heat dissipation material can be formed at the desired location. The time required for curing can be set by appropriately adjusting the content of polyamine (A) in the main agent relative to the total of polyamine (A) and diol (C), and 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 main agent. Specifically, it can be cured with a holding time of about 6 to 48 hours.

[0044] Since the curable composition is a composition that can be cured at room temperature, even when it is formed on the surface of a heat-sensitive member (such as a CPU), it can be cured without substantially damaging such a member to form the target heat dissipation material. The thermal conductivity of the heat dissipation material thus formed is usually 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). Also, the total filling rate of the inorganic filler (D1) and the inorganic filler (D2) in the heat dissipation material thus formed is preferably 65 to 95% by mass. Therefore, 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 body such as a heat generating electronic component provided inside an electronic device and a radiator such as a heat sink.

[0045] To apply the two-component 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 static mixer (dispenser) for two-component mixing equipped with a nozzle capable of discharging the curable composition, which is a liquid mixture of the two components, from the tip, and extrude the curable composition from the tip of the nozzle while mixing the two liquids (main component and curing agent). The above-mentioned curable composition has a sufficiently ensured pot life, and even when the main component and the curing agent are mixed, it does not cure immediately under room temperature conditions and can be easily applied to a desired location. Furthermore, since the curable composition can be extruded from the tip of a thin nozzle while ensuring the pot life, it can be injected even into a narrow gap (gap) between members and has excellent versatility.

[0046] The heat dissipation material of this embodiment is excellent in adhesion to various base material surfaces and the like, but can be easily peeled off from the base material surface and the like by heating. To peel off the heat dissipation material, for example, it may be heated at 80 to 120 °C for 30 minutes or more. By heating in this way, the adhesion (adhesiveness) is reduced and it can be easily peeled off from the surface of the base material or the like, so the heat dissipation material of this embodiment is excellent in recyclability (repairability).

[0047] <Article> One embodiment of the article of the present invention includes a heating element and the above-mentioned heat dissipation material disposed in contact with the heating element. Examples of the heating element include various circuit boards, as well as electronic components such as semiconductor devices. Examples of the semiconductor device include power semiconductor devices, LEDs, and power modules such as inverter devices. The semiconductor device is mounted 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.

[0048] The heat dissipation material has excellent adhesion to the surface of a heating element, a radiator, etc., even when it is silicone-free, and has a high thermal conductivity. Further, since the heat dissipation material can be formed under room temperature conditions, it can be suitably provided for a heating element of an electronic component that is vulnerable to heat. Furthermore, since the heat dissipation material can be easily peeled off by moderately heating, its recyclability is also good.

[0049] Even when the heat dissipation material is arranged in contact with the heating element, it will not be easily peeled off by the heat of the heating element as long as it is in contact with a radiator (cooling unit) such as a heat sink or a radiator for heat dissipation. On the other hand, since the adhesion decreases when the function of the cooling unit is stopped, it can be easily peeled off and disassembled for recycling.

Example

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

[0051] <Preparation of materials> Various materials shown in Table 1 were prepared. In Table 1, both "OH1" and "OH2" are diols having side chains (having a branched structure). "OH1" is a polyester-based diol containing a structural unit derived from 3-methyl-1,5-pentanediol, and "OH2" is 1,3-butanediol (1,3-butylene glycol). Also, both "NCO1" and "NCO2" are aliphatic polyisocyanates (aliphatic polyisocyanate modified bodies (nurate bodies)). Furthermore, the particle shapes of "filler8 to 10" are all spherical.

[0052] TIFF2025110770000001.tif137170

[0053] <Blending of components for the main agent> (Blending a01) 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, 1.5 parts of NH4, 7 parts of NH5, and 1.5 parts of OH1 were added. After dehydration treatment by heating under reduced pressure, it was stirred at 100 °C for 1 hour under a nitrogen stream to be uniform, and a main component for the main agent (formulation a01) with a polyamine (A) content of 85% and a total active hydrogen amount of 95.0 mgKOH / g was obtained.

[0054] (Formulations a02 - a15) Except for using each component of the type and amount (unit: part) shown in the middle row of Table 2, in the same manner as in the case of the aforementioned formulation a01, main components for the main agent (formulations a02 - a15) were obtained. In Table 2, "maximum amine value (mgKOH / g)" is the amine value of the polyamine (A) used when there is one type of polyamine (A) used, and is the largest amine value when two or more types of polyamine (A) are used. Also, "average amine value (mgKOH / g)" is the amine value of the polyamine (A) used when there is one type of polyamine (A) used, and is the average value of the amine values of two or more types of polyamine (A) when two or more types of polyamine (A) are used.

[0055] TIFF2025110770000002.tif115170

[0056] <Performance Evaluation of the Main Component for the Main Agent> For the prepared main component for the main agent, the following performance evaluations were carried out. The results are shown in Table 3.

[0057] (Pot life) The main ingredient was mixed with polyisocyanate (trade name "Duranate TSE-100", Asahi Kasei) at a mass ratio of 1:1 and stirred for about 1 minute to obtain a uniform mixed solution. After enclosing the obtained mixed solution in a sealed container, it was kept at room temperature (25°C). When the liquid level of the mixed solution did not tilt even after tilting the sealed container by about 90° and leaving it for 1 minute, it was judged that the fluidity was lost, and the time until the fluidity was lost was defined as the pot life. Then, the pot life was evaluated according to the evaluation criteria shown below. In this evaluation, the use of a dispenser (static mixer) with a two-component mixing specification is assumed. In this dispenser, the replacement of the contents within 1 hour is assumed, and if the usage amount is large, it is possible to use up the contents within 30 minutes. ◎: It maintained fluidity for 3 hours or more. ○: It maintained fluidity for 1 hour or more and less than 3 hours. △: It maintained fluidity for 30 minutes or more and less than 1 hour. ×: The fluidity was lost immediately after mixing or within less than 30 minutes.

[0058] (Normal adhesion) The mixed solution prepared during the evaluation of the above-mentioned "pot life" was applied to a SUS plate to prepare a test piece by bonding two SUS plates together. After leaving the prepared test piece at room temperature (25°C) for 1 day, the two SUS plates were peeled off by hand, and the normal adhesion was evaluated according to the evaluation criteria shown below. If the curing has progressed to a certain extent or more, it will not peel off or interface peel, so it can be evaluated that the normal adhesion is good. On the other hand, if cohesive failure occurs or it is uncured, the desired physical properties are not exhibited, and it is evaluated as unqualified. For formulations a11 and a12, since the fluidity was lost immediately after mixing, the evaluation of normal adhesion and the evaluation of heat peeling described later could not be carried out. On the other hand, for formulation a10, since it had a pot life within the measurable range (the fluidity was lost within less than 30 minutes), the evaluation of normal adhesion and the evaluation of heat peeling described later could be carried out. ◎: It did not peel off. 〇: Interface peeling occurred. △: Cohesive failure occurred. ×: It was uncured (liquid or syrup-like).

[0059] (Heat peeling) The test piece prepared during the evaluation of the above "normal adhesion" was heat-treated at 80 °C for 30 minutes, and the heat peeling (repairability) was evaluated according to the evaluation criteria shown below. ○: Peeled off. ×: Did not peel off.

[0060] TIFF2025110770000003.tif46170

[0061] <Preparation of the main agent> Each component in the types and amounts (unit: part) shown in Table 4 was mixed and stirred for 5 minutes using a stirring mixer (trade name "Awatori Ren Taro", manufactured by Shin Ki Co., Ltd.) to obtain the main agents of Formulation Examples A01 to A12. The "filling rate (%)" in Table 4 is the ratio (%) of the inorganic filler in the main agent.

[0062] TIFF2025110770000004.tif138170

[0063] <Preparation of the curing agent> Each component in the types and amounts (unit: part) shown in Table 5 was mixed and stirred for 5 minutes using a stirring mixer (trade name "Awatori Ren Taro", manufactured by Shin Ki Co., Ltd.) to obtain the curing agents of Formulation Examples B01 to B12. The "filling rate (%)" in Table 5 is the ratio (%) of the inorganic filler in the curing agent.

[0064] TIFF2025110770000005.tif123170

[0065] <Preparation of the paint (curable composition)> A paint (two-component curable composition) to be applied using a two-component mixing dispenser (static mixer) by combining the main agent and the curing agent in the types and amounts (unit: part) shown in Table 6 was prepared. The "filling rate (%)" in Table 6 is the ratio (%) of the inorganic filler in the entire curable composition (total of the main agent and the curing agent).

[0066] TIFF2025110770000006.tif194170

[0067] <Evaluation of Paint (Curable Composition) (Thermal Conductivity) The thermal conductivity of the cured product of the paint (curable composition) was measured by the hot disk method (ISO 22007-2). Specifically, after applying the paint to a mold (10 cm × 10 cm), it was pressed under a constant pressure. Then, it was aged at 40°C for 96 hours to obtain a film-like cured product. And the thermal conductivity of the obtained cured product (heat dissipation material) was measured using a thermal physical property measuring device (trade name "TPS2500S", manufactured by Kyoto Electronics Industry Co., Ltd.). The results are shown in Table 7.

[0068] (Pot Life) After each paint (combination of main agent and curing agent) was put into a two-component mixing static mixer and discharged, it was left for a predetermined time, and the standing time until it hardened at the tip of the static mixer and could no longer be discharged was defined as the pot life. And the pot life was evaluated according to the following evaluation criteria. The results are shown in Table 7. ◎: It could be used for 3 hours or more. ○: It could be used for more than 1 hour and less than 3 hours. △: It could be used for more than 30 minutes and less than 1 hour. ×: It became unusable in less than 30 minutes.

[0069] (Normal Adhesion) Each paint (combination of main agent and curing agent) was put into a two-component mixing static mixer. The paint was discharged from the tip of the static mixer and applied to a SUS plate, and a test piece was made by bonding two SUS plates together. After the prepared test piece was left at room temperature (25°C) for 1 day, the two SUS plates were peeled off by hand, and the normal adhesion was evaluated according to the following evaluation criteria. The results are shown in Table 7. ◎: It did not peel off. 〇: Interfacial peeling occurred. △: Cohesive failure occurred. ×: It was uncured (liquid or gummy).

[0070] (Heat peeling) The test piece prepared during the evaluation of the above "normal adhesion" was heat-treated at 80 °C for 30 minutes, and the heat peeling (repairability) was evaluated according to the evaluation criteria shown below. The results are shown in Table 7. ○: Peeled off. ×: Did not peel off.

[0071] TIFF2025110770000007.tif57170

Industrial applicability

[0072] The curable composition of the present invention is useful as a material for forming a heat dissipation material such as a heat dissipation sheet disposed between a heating element such as an electronic component and a radiator such as a heat sink.

Claims

1. A two-component curable composition containing a combination of a main agent and a curing agent used for forming a heat-dissipating material, wherein the main agent contains a polyamine (A), a diol (C), and an inorganic filler (D1), the curing agent contains a polyisocyanate (B) and an inorganic filler (D2), in the main agent, the content of the polyamine (A) in the total of the polyamine (A) and the diol (C) is 50 to 90% by mass, a curable composition in which 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 main agent is 0.75 to 2.

50.

2. The curable composition according to claim 1, wherein the amine value of the polyamine (A) is 300 mgKOH / g or less.

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 (D1) and the inorganic filler (D2) 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 (D1) in the main agent is 70 to 95% by mass, and the filling rate of the inorganic filler (D2) in the curing agent is 50 to 95% by mass. The curable composition according to claim 1.

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

7. The heat-dissipating material according to claim 6, having a thermal conductivity of 2.0 W / (m·K) or more.

8. The heat-dissipating material according to claim 6, wherein the total filling rate of the inorganic filler (D1) and the inorganic filler (D2) is 65 to 95% by mass.

9. A heating element, and an article comprising the heat-dissipating material according to claim 6 disposed in contact with the heating element.

Images