JPWO2012157627A1 - Curable heat dissipation composition - Google Patents

Abstract

The present invention includes (A) (a) a polyisocyanate compound, (b) a polycarbonate diol compound, (c) a urethane resin having a carboxyl group obtained by reacting a dihydroxy compound having a carboxyl group, (B) an epoxy resin, and ( C) It relates to a curable heat-radiating composition containing an inorganic filler (excluding barium sulfate and titanium oxide), wherein the content of the inorganic filler (C) is 50 to 96% by mass. As the inorganic filler (C), it is preferable to use flat boron nitride and particulate alumina, aluminum nitride or boron nitride in combination. The curable heat-dissipating resin composition of the present invention has high thermal conductivity, flexibility, and good adhesion to metal, and includes a power semiconductor, a semiconductor element including an optical semiconductor, a semiconductor device, a circuit metal plate, and the metal plate. It is extremely useful in the fields of circuits, circuit boards, and hybrid integrated circuits.

Description

  The present invention relates to a curable heat-dissipating composition that is not only excellent in heat dissipation, stress relaxation, and insulation reliability, but also excellent in adhesiveness during work and adhesion after curing, and suitable for fixing heat-dissipating electronic components.

  In recent years, there has been a problem of how to dissipate heat generated from electronic parts and the like in a narrow space due to downsizing and high power of electric and electronic parts. As one of the means, an insulating adhesive and sheet for conducting heat from the heat generation target part of the electronic component to the heat radiating member are used. As these adhesives and sheets, a composition in which a thermosetting resin is highly filled with an inorganic high heat dissipation filler is used. However, the amount of heat generated from electronic devices and electronic components tends to increase, and further improvements in thermal conductivity are required for adhesives and sheets used in these devices. For this purpose, it is necessary to fill the resin with an inorganic high heat dissipation filler more than ever. As the resin used in this application, an epoxy resin has been mainly used from the viewpoint of adhesiveness to a base material (for example, Japanese Patent Application Laid-Open No. 2008-101227 (Patent Document 1), Japanese Patent Application Laid-Open No. 2008-280436). Gazette (patent document 2), Unexamined-Japanese-Patent No. 2010-109285 (patent document 3)). However, since the surface area of the epoxy resin increases as the blending amount of the filler increases, the amount of the resin adsorbed on the filler surface increases. As a result, there is a problem that the adhesiveness to the substrate and the adhesiveness after curing are significantly reduced. Furthermore, the epoxy resin composition highly filled with the filler has a problem that the moldability is extremely inferior.

JP 2008-101227 A JP 2008-280436 A JP 2010-109285 A

  In view of the above circumstances, the present invention has adhesiveness when fixing electrical and electronic components even when filled with a high concentration of heat dissipation filler, has good workability, and has high adhesive strength by curing thereafter. The object is to provide a composition which can be fixed with

  As a result of intensive research, the present inventors have developed a resin composition that combines a urethane resin having a specific structure with excellent flexibility, filler filling property, and fluidity during heating with an epoxy resin. It is found that by filling a high heat-dissipating filler with a high concentration, a curable heat-dissipating composition excellent in heat dissipation, adhesiveness during work, adhesiveness after curing, and long-term reliability after bonding can be obtained. Completed the invention.

That is, this invention provides the following curable thermal radiation composition and adhesive agent.
[1] (A) Urethane resin having a carboxyl group, (B) epoxy resin and (C) inorganic filler (however, excluding barium sulfate and titanium oxide), and the content of the inorganic filler (C) is 50 It is -96 mass%, The curable thermal radiation composition characterized by the above-mentioned.
[2] The curable heat-radiating composition according to [1], wherein the inorganic filler (C) contains an inorganic filler having a thermal conductivity of 20 W / m · K or more.
[3] The curable heat-radiating composition according to [2], wherein the inorganic filler (C) contains at least 10% by mass of an inorganic filler having a thermal conductivity of 20 W / m · K or more.
[4] The urethane resin (A) having a carboxyl group comprises (a) a polyisocyanate compound, (b) a polycarbonate diol compound, (c) a dihydroxy compound having a carboxyl group, and (d) a monohydroxy compound as necessary. The curable heat-dissipating composition according to any one of [1] to [3], which is a resin obtained by reaction.
[5] The curable heat-dissipating composition according to [4], wherein the polycarbonate diol compound (b) has a number average molecular weight of 300 to 50,000.
[6] The curable heat dissipation composition according to [5] above, wherein at least 10 mol% of the diol constituting the polycarbonate diol compound having a number average molecular weight of 300 to 50,000 is an alicyclic compound having 6 to 30 carbon atoms. object.
[7] The curable heat-dissipating composition according to [4], wherein at least 10 mol% of the polyisocyanate compound (a) is an alicyclic compound having 6 to 30 carbon atoms other than the isocyanate group moiety.
[8] The curing according to any one of [1] to [4], wherein the urethane resin (A) having a carboxyl group has a number average molecular weight of 500 to 100,000 and an acid value of 5 to 150 mgKOH / g. Heat dissipation composition.
[9] The curable heat-radiating composition according to any one of [1] to [3], wherein the mass ratio of the urethane resin (A) having a carboxyl group and the epoxy resin (B) is 100: 10 to 100. .
[10] The curable heat-dissipating composition according to any one of [1] to [3], wherein the inorganic filler (C) is a mixture of a flat filler and a particulate filler.
[11] The curable heat-dissipating composition according to [10], wherein the mass ratio of the flat filler to the particulate filler is 90:10 to 10:90.
[12] The curable heat radiation composition according to [10] or [11], wherein the particulate filler is alumina, aluminum nitride, or boron nitride, and the flat filler is boron nitride.
[13] An adhesive comprising the curable heat dissipation composition according to any one of [1] to [12].

  The curable heat-dissipating composition of the present invention can be used as an adhesive having high heat dissipation and adhesiveness during work, adhesiveness after curing, long-term reliability, power semiconductor, semiconductor element including optical semiconductor, semiconductor It can be used for fixing electrical parts in the field of devices, metal plates for circuits, circuits made of the metal plates, circuit boards, hybrid integrated circuits and the like.

It is the top view (a) and XX sectional drawing (b) of the flat inorganic filler (C) used for this invention.

Hereinafter, the present invention will be described in detail.
In the present invention, a mixed resin composed of a urethane resin (A) having a carboxyl group and an epoxy resin (B) is used as the matrix resin of the curable heat radiation composition.

  Since the urethane resin (A) having a carboxyl group used in the present invention is excellent in flexibility and excellent in fluidity when heated, it has adhesiveness even when highly filled with a highly heat-conductive inorganic filler. Excellent adhesion during thermosetting. Moreover, since it is flexible, it has excellent stress relaxation properties and excellent moisture resistance reliability, and a cured product using the resin (A) has high long-term reliability.

  The urethane resin (A) having a carboxyl group used in the present invention comprises (a) a polyisocyanate compound, (b) a polycarbonate diol compound, (c) a dihydroxy compound having a carboxyl group, and (d) a monohydroxy as required. Obtained by reacting a compound.

  Specific examples of the polyisocyanate compound (a) include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, 1,3-trimethylene diisocyanate, 1,4-tetra Methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 1,9-nonamethylene diisocyanate, 1,10-decamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 2, 2'-diethyl ether diisocyanate, diphenylmethane diisocyanate, (o, m, or p) -xylene diisocyanate, methylene bis (cyclohexyl isocyanate), cyclo Xan-1,3-dimethylene diisocyanate, cyclohexane-1,4-dimethylene diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, 3,3′-methylene ditolylene-4,4′-diisocyanate, 4, Examples of the diisocyanate include 4′-diphenyl ether diisocyanate, tetrachlorophenylene diisocyanate, and norbornane diisocyanate. These diisocyanates can be used alone or in combination of two or more.

  In addition, a small amount of a polyisocyanate compound having three or more isocyanate groups such as triphenylmethane triisocyanate can be used as long as it does not gel.

  Among these, in particular, when a polyisocyanate compound having an alicyclic compound having 6 to 30 carbon atoms other than the isocyanate group portion is used, excellent performance is exhibited for long-term insulation reliability at high temperature and high humidity. Examples of the polyisocyanate compound having an alicyclic compound having 6 to 30 carbon atoms other than the isocyanate group portion include cyclohexane diisocyanate, isophorone diisocyanate, methylene bis (cyclohexyl isocyanate), cyclohexane-1,3-dimethylene diisocyanate, cyclohexane- 1,4-dimethylene diisocyanate may be mentioned.

  In order to develop suitable physical properties, the polyisocyanate compound having an alicyclic compound having 6 to 30 carbon atoms other than these isocyanate group portions is at least 10 mol% or more of the total polyisocyanate component, more preferably 30 mol. % Or more is desirable.

  Examples of the polycarbonate diol compound (b) include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2 -Methyl-1,8-octanediol, 1,9-nonanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanediol, 1,3-cyclohexanediol, tricyclohexanedi A polycarbonate diol compound having a structure in which diol components such as methanol and pentacyclopentadecanedimethanol are connected by a carbonate bond is preferable. These polycarbonate diol compounds can be used alone or in combination of two or more.

  Among these, when a diol having an alicyclic compound having 6 to 30 carbon atoms is used, excellent performance is exhibited particularly in terms of long-term insulation reliability at high temperature and high humidity. Examples of the diol having an alicyclic compound having 6 to 30 carbon atoms include 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanediol, 1,3-cyclohexanediol, and tricyclohexane. Examples include decanedimethanol and pentacyclopentadecanedimethanol.

  In order to express suitable physical properties, the polycarbonate diol having an alicyclic compound having 6 to 30 carbon atoms may be used at least 10 mol% or more, more preferably 30 mol% or more of the total polycarbonate diol component. desirable.

  The preferred number average molecular weight of the polycarbonate diol compound (b) used in the present invention is 300 to 50,000. If it is less than 300, the long-term insulation reliability at high temperature and high humidity decreases, and if it exceeds 50,000, urethane resin synthesis becomes difficult.

  Examples of the dihydroxy compound (c) having a carboxyl group include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, N, N-bishydroxyethylglycine, N, N-bishydroxyethylalanine and the like. Among these, dimethylolpropionic acid and dimethylolbutanoic acid are particularly preferable from the viewpoint of solubility in a solvent. These dihydroxy compounds having a carboxyl group can be used alone or in combination of two or more.

  The urethane resin having a carboxyl group can be synthesized with only the three components (a), (b) and (c) described above. However, the purpose is to impart radical polymerizability and reactivity, and the terminal isocyanate residue. In order to eliminate the influence, the monohydroxy compound (d) can be reacted.

  Examples of the monohydroxy compound (d) include 2-hydroxyethyl (meth) acrylate having a radical polymerizable double bond, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, caprolactone of each of the above (meth) acrylates, or Alkylene oxide adducts, glycerin di (meth) acrylate, trimethylol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, allyl alcohol, Examples thereof include allyloxyethanol, and examples of the monohydroxy compound imparting reactivity include compounds having a carboxylic acid such as glycolic acid and hydroxypivalic acid.

These monohydroxy compounds can be used alone or in combination of two or more. Of these, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, allyl alcohol, glycolic acid, and hydroxypivalic acid are preferred, and 2-hydroxyethyl (meth) acrylate is preferred. Is more preferable.
Monohydroxy compounds used for the purpose of eliminating the influence of terminal isocyanate residues include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, amyl alcohol, and hexyl alcohol. And octyl alcohol.

  The number average molecular weight of the carboxyl group-containing urethane resin of the present invention is preferably from 500 to 100,000, particularly preferably from 2,000 to 30,000. Here, the number average molecular weight is a value in terms of polystyrene measured by gel permeation chromatography. If the number average molecular weight is less than 500, the elongation, flexibility and strength of the cured film may be impaired. If the number average molecular weight exceeds 100,000, the solubility in a solvent will be low, and the viscosity will become too high even if dissolved. For this reason, restrictions in use are increased.

  The acid value of the carboxyl group-containing urethane resin of the present invention is preferably 5 to 150 mgKOH / g, particularly preferably 10 to 120 mgKOH / g. If the acid value is less than 5 mgKOH / g, the reactivity with the epoxy resin may be lowered and the heat resistance may be impaired, and if it exceeds 150 mgKOH / g, the cured film becomes too hard and brittle.

The urethane resin (A) having a carboxyl group used in the present invention is prepared by using a suitable solvent in the presence or absence of a known urethanization catalyst such as dibutyltin dilaurate, polyisocyanate compound (a), polycarbonate It is obtained by reacting the diol compound (b), the dihydroxy compound (c) having a carboxyl group, and, if necessary, the monohydroxy compound (d).
The reaction mode is not particularly limited, but representative examples for industrial implementation will be described.

  The organic solvent used for the reaction is not particularly limited as long as it has a low reactivity with isocyanate. For example, toluene, xylene, ethylbenzene, nitrobenzene, cyclohexane, isophorone, tetrahydrofuran, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol methyl ether acetate, propylene Glycol ethyl ether acetate, dipropylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, methyl methoxypropionate, ethyl methoxypropionate, methyl ethoxypropionate, ethyl ethoxypropionate, ethyl acetate, n-butyl acetate, isoamyl acetate, ethyl lactate , Acetone, methyl ethyl ketone, cyclohexanone, N, N-dimethyl Le formamide, N, N- dimethylacetamide, N- methylpyrrolidone, .gamma.-butyrolactone, dimethyl sulfoxide, chloroform and methylene chloride. In addition, the thing with low solubility of the carboxyl group-containing urethane to produce | generate is not preferable. In addition, it is not preferable that the solvent remains in the cured product in order to exhibit heat dissipation, and a solvent that easily volatilizes is preferable from that viewpoint. Among these, solvents such as toluene, tetrahydrofuran, ethyl acetate, acetone, and methyl ethyl ketone are particularly preferable. As a density | concentration of a reaction liquid, 10-90 mass% is preferable and, as for the urethane resin density | concentration which has a carboxyl group, 40-80 mass% is more preferable.

  Although there is no restriction | limiting in particular about the order which performs preparation of a raw material, Generally, after preparing the diol compound (dihydroxy compound containing the polycarbonate diol compound of (b) and the carboxyl group of (c) first), and making it melt | dissolve in a solvent. The polyisocyanate compound (a) is added dropwise at 20 to 150 ° C., more preferably 60 to 120 ° C., and then reacted at 50 to 160 ° C., more preferably 70 to 130 ° C.

  The feed molar ratio of the raw materials is adjusted by the desired number average molecular weight and acid value. When the monohydroxy compound (d) is introduced, the polyisocyanate compound (a) is such that the terminal is an isocyanate. Must be used in excess of the diol compound (polycarbonate diol compound of (b) + dihydroxy compound containing a carboxyl group of (c)).

  At the time when the reaction between the diol compound and the polyisocyanate compound is almost completed, the isocyanate remaining at both ends is reacted with the monohydroxy compound of (d) at 20 to 150 ° C., more preferably at 70 to 120 ° C. The monohydroxy compound is added dropwise and then held at the same temperature to complete the reaction.

  In the present invention, the epoxy resin (B) used as a curing agent for the urethane resin (A) having a carboxyl group preferably has at least two epoxy groups on average in one molecule. Such an epoxy resin may have, for example, a silicone skeleton, a urethane skeleton, or a polyimide skeleton.

  Such epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, hydrogenated bisphenol A type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, biphenyl type epoxy resins. Glycidier ether type epoxy resins such as biphenyl aralkyl type epoxy resin, naphthalene type epoxy resin, naphthalene aralkyl type epoxy resin, triphenylmethane type epoxy resin, trimethylolpropane triglycidyl ether, and pentaerythritol polyglycidyl ether, hexahydrophthal Acid glycidyl ester, dimer acid glycidyl ester, triglycidyl isocyanurate, and tetraglycidyl diaminodiphenyl Glycidyl amine type epoxy resins such as Tan; and epoxidized polybutadiene, and linear aliphatic epoxy resins such as epoxidized soybean oil. The said epoxy resin can be used individually or in mixture of 2 or more types.

  The mass ratio of the urethane resin (A) having a carboxyl group and the epoxy resin (B) is preferably 100: 10 to 100, and more preferably 100: 20 to 80. When the ratio of the epoxy resin is less than 10, the curing reaction does not proceed sufficiently. If it exceeds 100, the moldability deteriorates, so that the inorganic filler cannot be highly filled, and the tackiness and adhesiveness after curing also deteriorate.

As an inorganic filler (C) used by this invention, arbitrary things can be used if it has a function of heat conduction. However, barium sulfate and titanium oxide are not included in the inorganic filler (C) used in the present invention.
Examples of the inorganic filler (C) include ceramics such as silica, alumina, boron nitride, aluminum nitride and silicon carbide, carbon materials such as diamond and graphite, and metal powders such as copper, aluminum, iron and silver. Examples of the silica include fused silica produced by melting high-purity silica stone and crystalline silica produced by pulverizing natural quartz.
The shape of the inorganic filler (C) may be either particulate or flat, or a mixture thereof. Examples of the particulate filler include alumina, aluminum nitride, boron nitride (for example, cubic), silica, diamond, and metal powder. Examples of the flat filler include boron nitride (for example, hexagonal), graphite, and metal powder. Etc.
The inorganic filler (C) can contain an inorganic filler having a thermal conductivity of 20 W / m · K or more, at least 10% by mass, preferably at least 20% by mass. Thereby, the function of heat conduction is further improved. Examples of the inorganic filler having a thermal conductivity of 20 W / m · K or more include ceramics such as alumina, boron nitride, aluminum nitride, and silicon carbide, carbon materials such as diamond and graphite, and metal powders such as copper, aluminum, iron, and silver. Can be mentioned.

  The thermal conductivity of the inorganic filler used in the present invention is measured by a method defined in JIS R 1611 (2010), a thermal diffusivity, specific heat, and thermal conductivity test method of fine ceramics by a laser flash method.

ここで、無機フィラーの比表面積は、窒素ガス吸着法（ＢＥＴ法）によって実測した値である。ＢＥＴ法は液体窒素温度下で、粉体に単分子の吸着占有面積がわかっている窒素ガスを吸着させることにより比表面積を測定する方法である。The inorganic filler (C) is 50 to 96% by mass, more preferably 55 to 92% by mass in the composition containing the urethane resin (A) having a carboxyl group, the epoxy resin (B) and the inorganic filler (C). Thus, the object of the present invention can be achieved. If it is less than 50% by mass, sufficient heat dissipation is not exhibited. When it exceeds 96 mass%, the tackiness of the composition, the adhesiveness after curing, etc. cannot be sufficiently obtained.
Moreover, the compounding quantity of an inorganic filler (C) can also be expressed by the sum total of the surface area of the inorganic filler in a curable thermal radiation composition. In this case, the total surface area of the inorganic filler is preferably 50 to 350 m ^{2 and} more preferably 70 to 300 m ² per 100 g of the curable heat radiation composition. When it is less than 50 m ² , sufficient heat dissipation is not exhibited, and when it exceeds 350 m ² , the adhesiveness of the composition, the adhesiveness after curing, and the like cannot be sufficiently obtained.
The total surface area of the inorganic filler can be determined by the following method. That is, for example, when only P1 mass% of the filler 1 having a specific surface area S1 is contained in the curable heat-radiating composition, the surface area of the filler per 100 g of the curable heat-radiating composition is (S1 × P1). Furthermore, when the curable heat-radiating composition contains P2% by mass of the filler 2 having a specific surface area S2, the surface area of the filler per 100 g of the curable heat-radiating composition is (S1 × P1 + S2 × P2). Therefore, the sum total of the surface area of the inorganic filler per 100 g of the curable heat-radiating composition containing the n-component inorganic filler is represented by the following general formula.

Here, the specific surface area of the inorganic filler is a value measured by a nitrogen gas adsorption method (BET method). The BET method is a method for measuring the specific surface area by adsorbing nitrogen gas whose adsorption occupying area of a single molecule is known to a powder at a liquid nitrogen temperature.

Moreover, in the composition of this invention, an inorganic filler (C) can be used combining a particulate thing and a flat thing. The thermal conductivity of the cured product can be improved compared to when the particulate material is used alone, and the thermal conductivity of the cured product is more isotropic than when the flat material is used alone. Can be granted.
In addition, in this invention, flat shape is ratio of the major axis L of particle | grains 1 and thickness t, as shown in the top view (a) and XX sectional drawing (b) of the inorganic filler particle 1 in FIG. Means 5: 1 to 20: 1. The measurement can be performed with a scanning electron microscope.
In the present invention, the particulate form means a form that is typically spherical and has a flatness smaller than that of the flat shape.

Boron nitride (for example, hexagonal crystal) and graphite, which are representative examples of flat fillers, have anisotropy in thermal conductivity. The thermal conductivity of hexagonal boron nitride is about 60 to 63 W / m · K in the plane direction and about a fraction of the value in the plane direction in the direction perpendicular to the plane direction. Is known to be several times larger. When the flat filler is applied to the base material or formed into a sheet by applying pressure, the flat filler has a property of being arranged in parallel to the surface direction, and thus has excellent heat dissipation in the surface direction. However, since the function of heat dissipation may be necessary not only in the surface direction but also in the thickness direction, it is necessary to arrange flat fillers randomly or in the thickness direction.
In the curable heat-radiating composition of the present invention, the flat filler can be randomly oriented by blending the particulate filler in a certain range, and the thermal conductivity in the thickness direction can be improved.

  In this invention, when mixing and using a flat filler and a particulate filler, 90: 10-10: 90 is preferable and the mass ratio has more preferable 85: 15-15: 85.

  When the mass ratio of the flat filler is 10 or more, the thermal conductivity is good, and when the mass ratio of the particulate filler is 10 or more, the thermal conductivity in the thickness direction is good. Become.

The flat filler and the particulate filler used in the curable heat dissipation composition of the present invention each have a preferable average particle diameter range from the viewpoints of moldability, smoothness of the cured product, and thermal conductivity. In the case of a flat filler, the average particle size is preferably 0.5 to 50 μm, more preferably 1 to 30 μm. In the case of a particulate filler, the average particle diameter is preferably 1 to 100 μm, more preferably 5 to 80 μm. The average particle diameter of the flat filler used simultaneously is smaller than the average particle diameter of the particulate filler, which is advantageous in terms of thermal conductivity in the thickness direction because the flat filler is randomly oriented.
These average particle diameters are values obtained by measuring the particle size distribution by the laser diffraction / scattering method. Specifically, it can be measured by using a laser diffraction / scattering particle size distribution analyzer (LMS-2000e) manufactured by Seishin Corporation.

  In the curable heat dissipation composition of the present invention, boron nitride is preferable as the flat filler, and alumina, aluminum nitride, and boron nitride are preferable as the particulate filler from the viewpoint of thermal conductivity, electrical insulation, and economy. As the flat nitride boron nitride, for example, UHP-1K (L: t = 8: 1) manufactured by Showa Denko KK, and as the particulate filler alumina, for example, CB manufactured by Showa Denko KK -A50S (average particle diameter of 50 μm), and FAN-f50J (average particle diameter of 50 μm) manufactured by Tokuyama Corporation can be preferably used as the aluminum nitride of the particulate filler.

  A curing accelerator can be added to the curable heat dissipation composition of the present invention for the purpose of promoting curability. Specific examples of the curing accelerator include tertiary amines, imidazole compounds, phosphine compounds and the like.

  Specific examples of the tertiary amine compound include triethylamine, dimethylcyclohexylamine, N, N-dimethylpiperazine, benzyldimethylamine, 2- (N, N-dimethylaminomethyl) phenol, 2,4,6-tris (N , N-dimethylaminomethyl) phenol, 1,8-diazabiscyclo (5.4.0) undecene-1, and the like.

  Specific examples of the imidazole compound include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenyl. Imidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-methylimidazole trimellitate, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2,4-diamino-6- [2′- Methylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-undecylimidazolyl- (1 ′)]-ethyl-s-triazine, 2-methylimidazole isocyanuric acid With adduct, 2-phenylimidazole and isocyanuric acid Objects, 2,4-diamino-6- [2'-methylimidazolyl- - (1 ')] - ethyl -s- triazine isocyanuric acid adduct, and the like.

  Specific examples of the phosphine compound include triphenylphosphine and tolylylphosphine.

  A coupling agent can be added to the curable heat-radiating composition of the present invention for the purpose of increasing the dispersibility of the inorganic filler in the resin component and the adhesion to the substrate. Examples of coupling agents include silane, titanate, and aluminum. In the present invention, silane coupling agents can be preferably used, and preferred specific examples thereof include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropyltrimethyl. Methoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltri And ethoxysilane.

  In the composition of the present invention, a monomer or oligomer having another polymerizable functional group can be used for the purpose of adjusting viscosity, physical properties, curability and the like. Specifically, styrene having a radical polymerizable group, styrene derivatives such as vinyl toluene, methyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isoamyl (meth) acrylate, Hexyl (meth) acrylate, 2-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, benzyl ( (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di ( ) Acrylate, ethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol # 400 di (meth) acrylate, 2,2-bis (4- (meth) acryloxypolyethyloxyphenyl) propane Bisphenol A di (meth) acrylate, EO modified bisphenol A di (meth) acrylate, propylene oxide (PO) modified bisphenol A di (meth) acrylate, hydrogenated bisphenol A di (meth) acrylate, isocyanuric acid ethylene oxide (EO) modified Di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane EO modified tri (meth) acrylate, trimethylolpropane PO modified tri (meth) acrylate (Meth) acrylic acid esters such as methacrylate, styrene oxide, monofunctional epoxy compounds such as phenyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl ester resin, unsaturated polyester resin, vinyl ester resin.

  The composition of this invention mix | blends the additive for adjusting a physical property to (A) urethane resin which has a carboxyl group, (B) epoxy resin, and (C) inorganic filler, and uses it as a curable heat dissipation composition as it is. However, it can be formed into a sheet by heating and pressing at a temperature at which curing does not proceed and used as an adhesive sheet. Moreover, you may shape | mold into shapes other than a sheet form. After the molding, it can be bonded by being pressure-bonded to the substrate and heated to a proceeding temperature.

  The curable heat dissipation composition of the present invention is a power semiconductor, a semiconductor element including an optical semiconductor, a semiconductor device, and a circuit as an adhesive having high heat dissipation and adhesiveness during work, adhesiveness after curing, and long-term reliability. It can be used for fixing electrical components such as metal plates, circuits made of the metal plates, circuit boards, and hybrid integrated circuit fields.

Hereinafter, the present invention will be described with reference to synthesis examples, examples and comparative examples, but the present invention is not limited to these examples.
The number average molecular weight of the urethane resin having a carboxyl group, the acid value, the thermal conductivity of the curable heat-radiating composition, the adhesive strength, and the elastic modulus of the molded and cured plate were measured (evaluated) by the following methods.

Number average molecular weight:
It calculated | required as a value converted into polystyrene using the gel permeation chromatography (Showa Denko Co., Ltd. product, Shodex (trademark) GPC SYSTEM-11).

Acid value:
About 0.2 g of a sample is precisely weighed with a precision balance in a 100 ml Erlenmeyer flask, and 10 ml of a mixed solvent of ethanol / toluene = 1/2 (mass ratio) is added and dissolved therein. Further, 1 to 3 drops of phenolphthalein ethanol solution is added to this container as an indicator, and the mixture is sufficiently stirred until the sample becomes uniform. This is titrated with a 0.1N potassium hydroxide-ethanol solution, and the end point of neutralization is taken when the indicator is slightly red for 30 seconds. The value obtained from the result using the following calculation formula is defined as the acid value of the resin.

Thermal conductivity of curable heat dissipation composition:
The thermal conductivity in the plane direction is 30 mm (length) x 28 mm (width) x 8 mm (thickness) using a rectangular parallelepiped test piece, using TPS-2500 (manufactured by Kyoto Electronics Co., Ltd.) and the hot disk method. It was measured. The thermal conductivity in the thickness direction was determined by measuring the thermal diffusivity using ai-Phase Mobile (manufactured by Eye Phase Co., Ltd.) by temperature wave thermal analysis, and obtaining the specific heat and density separately obtained. From the following formula.

Adhesive strength:
Using a test piece of copper (manufactured by Nippon Test Panel Co., Ltd., C100P / single-sided # 240 polishing), a sheet of the curable heat-dissipating composition was inserted into the copper test piece / polished surface, 130 ° C. 20 After heat-adhering for minutes, the measurement was performed in a shear mode in accordance with JIS K6852 (1994). In addition, the magnitude | size of the test piece was made into width 14mm, thickness 9mm, length 30mm, and the adhesion area was made into width 14x length 25mm.

Synthesis example 1: Urethane resin having a carboxyl group In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, C-1015N (polycarbonate diol manufactured by Kuraray Co., Ltd., raw material diol molar ratio 1,9-nonanediol: 2-methyl-1,8-octanediol = 15: 85, molecular weight 964) 330.2 g, 2,2-dimethylolbutanoic acid (manufactured by Nippon Kasei Co., Ltd.) 60.4 g as a dihydroxyl compound having a carboxyl group, Tetrahydrofuran (manufactured by Kanto Chemical Co., Inc.) 571.2 g was charged as a solvent, the temperature of the reaction solution was raised to 60 ° C., and a desiccant-W (manufactured by Sumika Bayer Urethane Co., Ltd.) as a polyisocyanate compound by a dropping funnel 180.4 g was added dropwise over 30 minutes. After completion of the addition, the reaction was further carried out at 60 ° C. for 6 hours, and after confirming that the isocyanate had almost disappeared, 5 g of isobutanol (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise, and the reaction was further carried out at 60 ° C. for 2 hours. went.
The number average molecular weight of the obtained urethane resin having a carboxyl group was 8600, and the acid value of the solid content was 39.6 mgKOH / g.

Synthesis example 2: Urethane resin having a carboxyl group In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, UM-CARB90 (manufactured by Ube Industries, Ltd., raw material diol molar ratio: cyclohexanedimethanol: hexanediol = 1) as a polycarbonate diol compound : 1, molecular weight 891) 315.7 g, 2,2-dimethylolbutanoic acid (manufactured by Nippon Kasei Co., Ltd.) 58.6 g as a dihydroxyl compound having a carboxyl group, tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd.) 554 as a solvent .7 g was charged, the temperature of the reaction solution was raised to 60 ° C., and 180.4 g of Desmodur-W (manufactured by Sumika Bayer Urethane Co., Ltd.) was dropped as a polyisocyanate compound over 30 minutes with a dropping funnel. After completion of the addition, the reaction was further carried out at 60 ° C. for 6 hours, and after confirming that the isocyanate had almost disappeared, 5 g of isobutanol (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise, and the reaction was further carried out at 60 ° C. for 2 hours. went.
The obtained carboxyl group-containing polyurethane had a number average molecular weight of 7,900 and an acid value of solid content of 40.2 mgKOH / g.

Example 1:
The equivalent ratio of the urethane resin having a carboxyl group (carboxyl group equivalent 1416) obtained in Synthesis Example 1 and the bisphenol A type epoxy resin (manufactured by Nippon Steel Chemical Co., Ltd., YD-128: epoxy equivalent 189) is 1.05: To the urethane / epoxy resin preparation (15% by mass) having a carboxyl group adjusted to 1.0, a flat inorganic filler UHP-1K (manufactured by Showa Denko K.K., boron nitride thermal conductivity as an inorganic filler) 60% w / m · K) (85% by mass, total surface area in 100 g of composition = 349 m ² ), and then kneaded using a rotating / revolving mixer (Sinky Co., Ltd., Foaming Kneading Taro) The objective curable heat radiating resin composition was obtained.
This curable heat radiating composition was heat-molded at 130 ° C. for 20 minutes using a hot press to produce a molded and cured plate that was cured into a sheet, and when this thermal conductivity was measured, the thermal conductivity in the plane direction was An extremely high value of 37.4 W / m · K was exhibited.

Examples 2-4:
The equivalent ratio of the carboxyl group-containing urethane resin (carboxyl group equivalent 1396) obtained in Synthesis Example 2 and the bisphenol A type epoxy resin (YD-128, manufactured by Nippon Steel Chemical Co., Ltd., epoxy equivalent 189) is 1.05: 1. The curability of Examples 2 to 4 was the same as Example 1 except that the mass% ratio of the carboxyl group-containing urethane / epoxy resin preparation adjusted to 0.0 and the inorganic filler was changed as shown in Table 1. A heat-dissipating resin composition was prepared to produce a molded and cured plate. Table 1 shows the thermal conductivity measurement results in these plane directions. A high thermal conductivity of 8 W / m · K or higher was obtained.

Comparative Example 1:
Inorganic filler (UHP-1K): A curable heat-dissipating resin composition was prepared in the same manner as in Example 1 except that the ratio of the carboxyl group-containing urethane / epoxy resin preparation was 40% by mass. Produced. When the thermal conductivity of this molded and hardened plate was measured, the thermal conductivity in the surface direction was 3.6 W / m · K.

Examples 5-7:
As the inorganic filler, spherical inorganic filler CB-A50S (manufactured by Showa Denko KK / alumina thermal conductivity 36 W / m · K), particulate inorganic filler FAN-f50J (manufactured by Tokuyama KK / aluminum nitride thermal conductivity 200 W / m · K) and flat inorganic filler UHP-1K (manufactured by Showa Denko KK, boron nitride) were used in the same manner as in Example 1 except that the composition was as shown in Table 2. A composition was prepared and a molded cured plate was produced. Table 2 shows the measurement results of each composition ratio, thickness direction thermal conductivity, and normal state adhesive strength of the curable heat radiation composition.

Comparative Example 2:
Commercially available novolac type phenolic resin BRG-556 (manufactured by Showa Denko KK, hydroxyl equivalent 103 (measured according to JIS K0070)) and bisphenol A type epoxy resin YD-128 (manufactured by Nippon Steel Chemical Co., Ltd., epoxy equivalent 189) Novolak epoxy resin preparation adjusted to an equivalent ratio of 1.05: 1.0: particulate aluminum nitride (FAN-f50J): boron nitride UHP-1K, 11.7: 71.6, respectively : 16.6 (mass% ratio), a curable heat radiation composition was prepared in the same manner as in Example 1, and a molded and cured plate was produced. Table 2 shows the measurement results of each composition ratio, thickness direction thermal conductivity, and normal state adhesive strength of the curable heat radiation composition.
The heat conductivity value in the thickness direction of this molded and hardened plate showed a comparatively high value of 6.3 W / m · K. When an attempt was made to measure the adhesive strength, a sheet made from this resin composition was It was poor in flexibility and poor in adhesion with copper and could not be adhered.

Comparative Example 3:
Epoxy resin preparation in which 100 parts by mass of bisphenol A type epoxy resin YD-128 (manufactured by Nippon Steel Chemical Co., Ltd., epoxy equivalent 189) and 2.5 parts by mass of 1-cyanoethyl-2-methylimidazole as a curing agent were added: particulate Aluminum nitride (FAN-f50J): Boron nitride UHP-1K was set to 11.7: 71.6: 16.6 (mass% ratio), respectively, and a curable heat radiation composition was prepared in the same manner as in Example 1. A molded and hardened plate was produced. Table 2 shows the measurement results of each composition ratio, thickness direction thermal conductivity, and normal state adhesive strength of the curable heat radiation composition.

Comparative Example 4:
Commercially available novolac type phenolic resin BRG-556 (manufactured by Showa Denko KK, hydroxyl equivalent 103 (measured according to JIS K0070)) and bisphenol A type epoxy resin YD-128 (manufactured by Nippon Steel Chemical Co., Ltd., epoxy equivalent 189) Novolak epoxy resin preparation adjusted to an equivalent ratio of 1.05: 1.0: particulate aluminum nitride (FAN-f50J): boron nitride (UHP-1K) 9.1: 73, respectively 8: 17.1 (mass% ratio), a curable heat radiation composition was prepared in the same manner as in Example 1, and a molded and cured plate was produced. Table 2 shows the measurement results of each composition ratio, thickness direction thermal conductivity, and adhesive strength of the curable heat radiation composition.

  The curable heat-dissipating resin composition of the present invention, in which an epoxy and an inorganic filler are blended using a carboxyl group-containing urethane resin, has high thermal conductivity, flexibility, and good adhesion to metals. It is extremely useful in the field of semiconductor elements including semiconductors, semiconductor devices, circuit metal plates, circuits made of the metal plates, circuit boards, hybrid integrated circuits, and the like.

  1 Flat inorganic filler

Claims (13)

  (A) A urethane resin having a carboxyl group, (B) an epoxy resin, and (C) an inorganic filler (excluding barium sulfate and titanium oxide), and the content of the inorganic filler (C) is 50 to 96 mass. % Curable heat-dissipating composition.   The curable heat-radiating composition according to claim 1, wherein the inorganic filler (C) contains an inorganic filler having a thermal conductivity of 20 W / m · K or more.   The curable heat-radiating composition according to claim 2, wherein the inorganic filler (C) contains at least 10% by mass of an inorganic filler having a thermal conductivity of 20 W / m · K or more.   The urethane resin (A) having a carboxyl group is reacted with (a) a polyisocyanate compound, (b) a polycarbonate diol compound, (c) a dihydroxy compound having a carboxyl group, and (d) a monohydroxy compound as required. It is resin obtained, The curable thermal radiation composition of any one of Claims 1-3.   The curable heat-dissipating composition according to claim 4, wherein the polycarbonate diol compound (b) has a number average molecular weight of 300 to 50,000.   The curable heat-dissipating composition according to claim 5, wherein at least 10 mol% of the diol constituting the polycarbonate diol compound having a number average molecular weight of 300 to 50,000 is an alicyclic compound having 6 to 30 carbon atoms.   The curable heat-radiating composition according to claim 4, wherein at least 10 mol% of the polyisocyanate compound (a) is an alicyclic compound having 6 to 30 carbon atoms other than the isocyanate group portion.   The curable heat-dissipating composition according to any one of claims 1 to 4, wherein the urethane resin (A) having a carboxyl group has a number average molecular weight of 500 to 100,000 and an acid value of 5 to 150 mgKOH / g.   The curable heat-radiating composition according to any one of claims 1 to 3, wherein a mass ratio of the urethane resin (A) having a carboxyl group and the epoxy resin (B) is 100: 10 to 100.   The curable heat dissipation composition according to any one of claims 1 to 3, wherein the inorganic filler (C) is a mixture of a flat filler and a particulate filler.   The curable heat-dissipating composition according to claim 10, wherein the mass ratio of the flat filler to the particulate filler is 90:10 to 10:90.   The curable heat-dissipating composition according to claim 10 or 11, wherein the particulate filler is alumina, aluminum nitride, or boron nitride, and the flat filler is boron nitride.   The adhesive agent which consists of a curable thermal radiation composition of any one of Claims 1-12.