Insulating compositions, thermosetting insulating adhesive sheets, insulating adhesive layers, and composite members

Abstract

To provide an insulating composition, a thermosetting insulating adhesive sheet, an insulating adhesive layer and a composite member having excellent insulation property, moisture resistance, heat resistance (solder reflow resistance), thermal conductivity, adhesiveness and flexibility after long-term heating.SOLUTION: There is provided an insulating composition which is a thermosetting composition and comprises a polyimide resin (A) containing acid anhydride group ends, which is a reaction product of tetracarboxylic dianhydride and a polyamine compound containing a dimer diamine, a curing agent (B) and a thermally conductive filler (C). The thermally conductive filler (C) includes boron nitride (c) having a tapped density of 0.4 g / cm3 and less than 2.3 g / cm3.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a thermosetting insulating composition containing a polyimide resin. It also relates to a thermosetting insulating adhesive sheet, an insulating adhesive layer, and a composite member.

Background Art

[0002] With the development of high performance, high density, and thinness of electronic components mounted on electronic devices, high performance materials are also required for insulating compositions used as insulating materials, encapsulating materials, adhesive materials, protective materials, etc. for electronic components.

[0003] For example, in Patent Document 1, with the problem of providing an adhesive composition having sufficiently good low-temperature adhesiveness, heat-time fluidity, and reliability after heat curing, an acid containing dimer acid and a polycondensation polymer selected from a polyamide resin or a polyamideimide resin having a Tg of 150°C or lower obtained by polycondensing a diamine and / or a diisocyanate, and an adhesive composition containing a thermosetting resin have been proposed.

[0004] In Patent Document 2, with the problem of providing an adhesive composition excellent in thermal conductivity, high light reflectivity, heat resistance, and insulation, a binder resin selected from a polyethersulfone resin or a polyimide resin having a specific structure, a thermosetting resin, a curing agent, a thermal conductivity filler, and an adhesive composition containing a titanium oxide filler having a specific average particle diameter have been disclosed.

[0005] Also, in Patent Document 3, with the problem of providing a heat dissipation sheet excellent in heat dissipation and dimensional stability at high temperatures, a heat dissipation sheet composed of a heat dissipation filler and an imide-modified elastomer having a polyurethaneimide structure has been disclosed.

[0006] Furthermore, Patent Document 4 discloses an insulating composition containing a polyimide resin containing 60 mol% or more of diamine residues having a siloxane structure in all diamine residues, a thermosetting resin, and a thermal conductivity filler, with the objective of providing a sheet having excellent heat resistance, thermal conductivity, low elastic modulus, and excellent heat responsiveness.

[0007] The thermosetting insulating composition can temporarily fix between dissimilar members or parts before curing and function as an insulating adhesive layer after the thermosetting treatment. However, an insulating adhesive layer with excellent insulating reliability capable of coping with the recent high density and narrow wiring pitch of electronic components is required. In addition, in the manufacturing process of semiconductor packages, they are exposed to a high temperature of about 200 to 300 °C in the reflow process, and an insulating adhesive layer having excellent adhesive strength even after such a high-temperature heat history is required.

[0008] The applications of electronic components are diverse. For example, when mounted on in-vehicle electronic devices, they may be used under harsh conditions of high humidity, and a highly reliable insulating adhesive layer is required even in a high-humidity environment. Furthermore, with the recent miniaturization and high-powerization of electronic components, the amount of heat generated from heat sources has increased. In addition to excellent heat resistance, an insulating adhesive layer with high thermal conductivity that can efficiently diffuse the heat inside the electronic components to prevent malfunction due to heat generation is required.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0010] If a material can be provided that exhibits excellent adhesion while possessing insulating reliability, moisture resistance, heat resistance, flexibility after prolonged heating, and thermal conductivity, it can be expected to be used as a replacement material for conventional adhesive layers and to improve the performance of electronic components. Furthermore, it can provide a material with excellent handling properties for applications other than adhesive layers. However, while incorporating a large amount of thermally conductive filler into the resin improves thermal conductivity, other properties such as adhesion tend to deteriorate. Therefore, there is a demand in the market for a thermosetting insulating composition that can provide an insulating adhesive layer that balances insulating properties, thermal conductivity, heat resistance, moisture resistance, flexibility after prolonged heating, and adhesion. Furthermore, the above-mentioned issues are common to all applications requiring insulation reliability, moisture resistance, heat resistance, thermal conductivity, and adhesion.

[0011] The present invention has been made in view of the above background, and aims to provide an insulating composition, a thermosetting insulating adhesive sheet, an insulating adhesive layer, and a composite member that are excellent in insulating properties, moisture resistance, heat resistance (solder reflow resistance), thermal conductivity, flexibility after long-term heating, and adhesion. [Means for solving the problem]

[0012] After diligent research by the inventors, we discovered that the problems of the present invention can be solved in the following embodiment, and thus completed the present invention. In other words, it contains a polyimide resin (A) which is a reaction product of a tetracarboxylic dianhydride and a polyamine compound containing siloxanediamine, a curing agent (B), and a thermally conductive filler (C). As a thermally conductive filler (C), the tap density is 0.4 g / cm³. 3 More than 2.3g / cm 3 This can be solved by a thermosetting insulating compound containing boron(c) nitride with a concentration of less than 150. [Effects of the Invention]

[0013] According to the present invention, by providing an insulating composition, thermosetting insulating adhesive sheet, insulating adhesive layer, and composite member that are excellent in insulating properties, moisture resistance, heat resistance (solder reflow resistance), thermal conductivity, flexibility after long-term heating, and adhesion, it is possible to improve the performance, density, and thinness of electronic components mounted in electronic devices, and in particular, it has the excellent effect of being able to be mounted in automotive electronic devices used in harsh environments with large temperature fluctuations. [Modes for carrying out the invention]

[0014] The present invention will now be described in detail. It goes without saying that other embodiments are also included in the scope of the present invention, as long as they are consistent with the spirit of the invention. Furthermore, numerical ranges specified using "~" in this specification include the numerical values ​​before and after "~". Also, in this specification, "film" and "sheet" are not distinguished by thickness. Furthermore, unless otherwise noted, the various components mentioned in this specification may be used individually or in combination of two or more.

[0015] [Insulating composition] The insulating composition according to this embodiment is a thermosetting insulating composition containing a polyimide resin (A) which is a reaction product of a tetracarboxylic dianhydride and a polyamine compound containing siloxanediamine, a curing agent (B), and a thermally conductive filler (C). The thermally conductive filler (C) has a tap density of 0.4 g / cm³. 3 More than 2.3g / cm 3 Contains boron(c) nitride which is less than 100%.

[0016] Here, insulating properties refer to a volume resistivity of 1.0 × 10⁻⁶. 8 This refers to materials with a thermal conductivity of Ω·cm or greater. "Thermal conductive filler (C)" refers to particles that, when added to an insulating composition, enhance its thermal conductivity when cured. Furthermore, a thermosetting type refers to a composition in which the resin hardens by forming a three-dimensional cross-linked structure upon heating. A cured product refers to a state in which the curing reaction does not substantially proceed even with further heating.

[0017] The insulating composition of this embodiment can be, for example, in powder form, film form, sheet form, plate form, pellet form, paste form or liquid form. The liquid or paste insulating composition can be obtained by adjusting the viscosity using a solvent. Also, the film-like, sheet-like, and plate-like insulating compositions can be formed, for example, by applying a liquid or paste insulating composition and drying the solvent. Further, the powder-like and pellet-like insulating compositions can be obtained, for example, by pulverizing or dividing the insulating composition in the form of the film or the like into a desired size.

[0018] According to the insulating composition of this embodiment, a polyimide resin (A) which is a reaction product of a tetracarboxylic dianhydride and a polyamine compound containing siloxanediamine, a curing agent (B), and boron nitride (c) having a tap density of 0.4 g / cm 3 or more and less than 2.3 g / cm 3 By containing a heat conductive filler (C), an insulating composition excellent in the insulating property and adhesiveness of its cured product can be obtained. Further, the cured product is excellent in moisture resistance, heat resistance (solder reflow resistance), flexibility after long-term heating, and heat conductivity. The reason is that the siloxane structure promotes the suppression of the packing around the imide ring of the polyimide resin (A) and promotes the uniform dispersion of the imide ring. By combining with a heat conductive filler (C) containing boron nitride (c) having a tap density of 0.4 g / cm 3 or more and less than 2.3 g / cm 3 It is presumed that the dispersibility of the heat conductive filler (C) when made into a cured product can be significantly improved. Also, by including a siloxane structure excellent in flexibility, the internal stress generated in the insulating adhesive layer can be relaxed, and the decrease in adhesive strength and the occurrence of cracks due to the stress generated by repeated high and low temperatures can be suppressed, and an insulating adhesive layer having adhesiveness, heat conductivity, moisture resistance, flexibility after long-term heating, and insulating property after solder reflow can be obtained. Hereinafter, each component of the insulating composition of this embodiment will be described in detail.

[0019] [Polyimide Resin (A)] Polyimide resin (A) is a reaction product of a tetracarboxylic dianhydride and a polyamine compound containing siloxanediamine.

[0020] Polyimide resin (A) can be obtained by known polymerization methods. A suitable example of a production method is to dissolve a monomer containing a tetracarboxylic dianhydride and a polyamine compound in a solvent and polymerize it by stirring at a temperature of, for example, 60 to 120°C for 0.1 to 2 hours to produce a polyimide precursor, a polyamic acid resin, which is then converted to an imide group by cyclization upon heating. Preferably, the diamine compound is 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and particularly preferably 98 mol% or more, out of 100 mol% of the polyamine compound.

[0021] Examples of organic solvents used in polymerization include N-methyl-2-pyrrolidone (NMP), 2-butanone, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, 4-methyltetrahydropyran (MTHP), diglyme, triglyme, and cresol. The solvent can be used alone or in combination of two or more. Aromatic hydrocarbons such as xylene and toluene can also be used in combination.

[0022] The method for obtaining polyimide resin by imidizing a polyimide precursor is not particularly limited, but one example is heating in a solvent at a temperature of 80 to 400°C for 0.5 to 50 hours. A catalyst and / or dehydrating agent may be used as needed.

[0023] Examples of reaction catalysts include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, and heterocyclic tertiary amines such as pyridine, picoline, and isoquinoline. Examples of dehydrating agents include aliphatic acid anhydrides such as acetic anhydride and aromatic acid anhydrides such as benzoic anhydride.

[0024] The imidization rate (the rate of imide ring formation) is not limited, but from the viewpoint of effectively exhibiting the effect of long-term heat resistance, it is preferably 80% or more, more preferably 90% or more, and even more preferably 95-100%. The imidization rate can be determined by NMR or IR analysis.

[0025] (molecular chain end) The molecular chain ends of the polyimide resin (A) are not limited. From the viewpoint of improving the pot life when made into a sheet, it is preferable to include acid anhydride groups. The method of introducing acid anhydride groups to the molecular chain ends of the polyimide resin (A) is not particularly limited, and for example, a method in which the polymerizable functional groups of tetracarboxylic dianhydride are blended in a larger amount than the polymerizable functional groups of the polyamine compound can be applied. Depending on the desired weight-average molecular weight, for example, the equivalent ratio of polymerizable functional groups of tetracarboxylic dianhydride to polymerizable functional groups of the polyamine compound can be adjusted in a range of greater than 1.0 and less than or equal to 5.0. More preferably it is 1.01 to 3.0, and even more preferably 1.02 to 2.0. Alternatively, a polyimide precursor may be produced in which the equivalent ratio of polymerizable functional groups of tetracarboxylic dianhydride to polymerizable functional groups of the polyamine compound is 1 or less, and then acid anhydride groups may be introduced to the ends. Note that tetracarboxylic dianhydride and polyamine compounds may each be used independently, one or more, or in combination.

[0026] In addition to the combination of a polyimide resin (A) having a siloxane structure and a thermally conductive filler (C) containing boron nitride (c) at a specific tap density, it is believed that the presence of acid anhydride groups at the molecular chain ends further enhances the uniform dispersibility of the polyimide resin (A) itself and significantly improves its dispersibility with the thermally conductive filler (C). Furthermore, the combination of the siloxane structure and the ring structure formed by the acid anhydride groups at the molecular chain ends inhibits the packing properties around the highly planar imide ring, while simultaneously enhancing flexibility through a synergistic effect resulting from increased interaction between the molecular chain ends and the imide ring, leading to superior adhesion, moisture resistance, and heat resistance. From the viewpoint of effectively eliciting these effects, it is preferable that 80-100% of the molecular chain ends consist of acid anhydride groups, and more preferably 90-100% consist of acid anhydride groups. Note that "acid anhydride group" refers to a group represented by -C(=O)-OC(=O)-.

[0027] The polyimide resin (A) may contain molecular chain ends that do not have functional groups. For example, some of the acid anhydride groups at the molecular chain ends can be encapsulated with a monoamine compound to reduce the number of acid anhydride functional groups. This method allows for easy adjustment of the amount of acid anhydride groups at the molecular chain ends of the polyimide resin (A). The molecular chain ends of the polyimide resin (A) may also have functional groups other than acid anhydride groups, as long as this does not depart from the spirit of the present invention.

[0028] (Tetracarboxylic acid dianhydride) Tetracarboxylic acid dianhydrides are not particularly limited, but specific examples include pyromellitic acid dianhydride, 1,4-difluoropyromellitic acid dianhydride, 2,5-trifluoromethylpyromellitic acid dianhydride, trifluoromethylpyromellitic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-anthracenetetracarboxylic acid dianhydride, 2,3,6 ,7-Anthracenetetracarboxylic dianhydride, 9,9'-Bis(3,4-dicarboxyphenyl)fluorene dianhydride, 2,2-Bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-Bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-Bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-Bis(2,3-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, Bi (3,4-dicarboxyphenyl)sulfone dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,3,3',4'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-diphenylethertetracarboxylic acid dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 3,3',4,4'-diphenylmethanetetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 2,2-bis[4-(3,4 Examples include -dicarboxyphenoxy)phenyl]propane dianhydride, ethylene glycol dibenzoatetetracarboxylic dianhydride, benzene-1,4-diyrbis(1,3-oxo-1,3-dihydro-2-benzofuran-5-carboxylate), 4,4'-[propane-2,2-diyrbis(1,4-phenyleneoxy)]diphthalic acid dianhydride, and 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride. Also, 1,2,3,4-butanetetracarboxylic acid dianhydride, 1,2,3,4-pentanetetracarboxylic acid, 1,2,4,5-pentanetetracarboxylic acid, 1,2,3,4-hexanetetracarboxylic acid, 1,2,5,6-hexanetetracarboxylic acid, cyclobutane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, cyclohexane-1,2,3,4-tetracarboxylic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, 1-carboxy 2,3,5-cyclopentanetricarboxylic acid, 3-carboxymethyl-1,2,4-cyclopentanetricarboxylic acid, rel-dicyclohexyl-3,3',4,4'-tetracarboxylic acid, tricyclo[4.2.2.02,5]deca-9-ene-3,4,7,8-tetracarboxylic acid, 5-carboxymethylbicyclo[2.2.1]heptane-2,3,6-tricarboxylic acid, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic acid, bicyclo[2.2.2] Octa-7-ene-2,3,6,7-tetracarboxylic acid, bicyclo[3.3.0]octane-2,4,6,7-tetracarboxylic acid, 7,8-diphenylbicyclo[2.2.2]octa-7-ene-2,3,5,6-tetracarboxylic acid, 4,8-diphenyl-1,5-diazabicyclooctane-2,3,6,7-tetracarboxylic acid, 9-oxatricyclo[4.2.1.02,5]nonane-3,4,7,8-tetracarboxylic acid, 9,14-dioxopentacyclo[8.2.11,11 Examples include cyclo, bicyclo, and tricyclotetracarboxylic acids such as [14,7,02,10,03,8]tetradecane-5,6,12,13-tetracarboxylic acid; spiroring-containing tetracarboxylic acids such as 2,8-dioxaspiro[4.5]decane-1,3,7,9-terotone; and tetracarboxylic dianhydrides having an alicyclic hydrocarbon structure such as 1,3,3a,4,5,9b-hexahydro-5(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-c]furan-1,3-dione.

[0029] Tetracarboxylic acid dianhydrides are particularly preferred if they are compounds shown in the following general formula (1): [ka] (X 1 (This is a tetravalent residue of a tetracarboxylic acid, having at least one substituted or unsubstituted aromatic ring.) For example, the tetracarboxylic dianhydride having a general formula (1) structure with an aromatic ring can more effectively enhance the dispersibility of the thermally conductive filler (C), resulting in a better balance of adhesive strength, thermal conductivity, flexibility after long-term heating, and heat resistance. Specific examples of the above general formula (1) include pyromellitic dianhydride, 1,4-difluoropyromellitic dianhydride, 2,5-trifluoromethylpyromellitic dianhydride, trifluoromethylpyromellitic dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-anthracenetetracarboxylic acid dianhydride, and 2,3,6,7-anthracenetetracarboxylic acid dianhydride. Tracarboxylic acid dianhydride, 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, bis(3,4-di Carboxyphenyl) sulfone dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,3,3',4'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic acid dianhydride, 3,3',4,4'-diphenyl sulfone tetracarboxylic acid dianhydride, 3,3',4,4'-diphenylmethane tetracarboxylic acid dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride, 2,2-bis[4-(3,4-diphenyl] Examples include boxyphenoxy)phenyl]propane dianhydride, ethylene glycol dibenzoatetetracarboxylic dianhydride, benzene-1,4-diyrbis(1,3-oxo-1,3-dihydro-2-benzofuran-5-carboxylate), 4,4'-[propane-2,2-diyrbis(1,4-phenyleneoxy)]diphthalic acid dianhydride, and 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride.

[0030] A more suitable example is general formula (3): [ka] (R9 , R 10 Each of these is independently one of an alkyl group having 1 to 3 carbon atoms, a halogen atom, a hydroxyl group, a nitro group, a cyano group, and an alkoxy group having 1 to 3 carbon atoms, and n2 and n3 are independently 0 to 3, Y 1 These are single bonds, alkylene groups which may have substituents with 1 to 20 carbon atoms, -O-, -C(=O)-, -CH(OH)-, -S(=O)2-, -S-, -Si(CH3)2-, -(CF2) q -(where 1≦q≦10), -C(C n H 2n+1 )2-(where 1≦n≦10), -C(C m F 2m+1 )2-(where 1≦m≦10), or general formula (4): [ka] (R 11 , R 12 Each of these is independently one of an alkyl group having 1 to 3 carbon atoms, a halogen atom, a hydroxyl group, a nitro group, a cyano group, or an alkoxy group having 1 to 3 carbon atoms, and n4 and n5 are independently 0 to 4.

[0031] Examples of compounds that satisfy general formula (3) include 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-diphenylethertetracarboxylic acid dianhydride, 4,4'-[propane-2,2-diyrbis(1,4-phenyleneoxy)]diphthalic acid dianhydride, 4,4'-oxydiphthalic acid anhydride, and pyromellitic acid dianhydride.

[0032] (Polyamine compounds) The polyamine compound contains at least one siloxanediamine represented by general formula (2). Here, the siloxanediamine is a linear siloxane compound and does not include cyclic siloxane compounds. [ka] (In general formula (2), R 1R indicates a divalent hydrocarbon group, 2 Each of these independently represents a monovalent hydrocarbon group, and n1 represents an integer from 1 to 300.

[0033] The number-average molecular weight Mn of the siloxanediamine is preferably 200 to 25,000, more preferably 200 to 10,000, and even more preferably 200 to 5,000. When the number-average molecular weight is within this range, the siloxane skeleton in the polyimide resin (A) does not hinder the interaction between the imide ring and the heat-generating member or heat-dissipating base substrate, resulting in excellent adhesion, heat resistance, and moisture resistance. Furthermore, the viscosity of the polyimide (A) resin solution becomes appropriate, ensuring the handling of the coating liquid filled with the heat-conducting filler (C).

[0034] Specific examples of siloxanediamines that can be used include α,ω-bis(2-aminoethyl)polydimethylsiloxane, α,ω-bis(3-aminopropyl)polydimethylsiloxane, α,ω-bis(4-aminobutyl)polydimethylsiloxane, α,ω-bis(5-aminopentyl)polydimethylsiloxane, α,ω-bis[3-(2-aminophenyl)propyl]polydimethylsiloxane, α,ω-bis[3-(4-aminophenyl)propyl]polydimethylsiloxane, 1,3-bis(3-aminopropyl)tetramethyldisiloxane, and 1,3-bis(4-aminobutyl)tetramethyldisiloxane.

[0035] Examples of particularly suitable siloxanediamines available commercially include, for example, KF-8010, X-22-161A, and X-22-161B (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0036] The siloxanediamine content is preferably 10 to 80 mol%, more preferably 20 to 75 mol%, and even more preferably 30 to 71 mol%, relative to 100 mol% of the polyamine compound used to synthesize the polyimide resin (A). By using 10 to 80 mol% of siloxanediamine relative to 100 mol% of the polyamine compound, good adhesive strength, heat resistance, and moisture resistance can be achieved. If the content exceeds 80 mol%, the adhesive strength will decrease, and if it is less than 10 mol%, sufficient heat resistance and moisture heat resistance cannot be achieved.

[0037] Polyamine compounds may contain dimeramines. Dimeramines are diamine compounds having a dimer structure. Here, "dimer structure" refers to a structure derived from a fatty acid dimer (hereinafter referred to as a fatty acid dimer). Dimeramines can be compounds obtained by converting the carboxyl group of a dimer acid to an amino group. Conversion methods include, for example, amidating a carboxylic acid, aminating it by Hoffmann rearrangement, and then distilling and purifying it. Dimer acid is a polybasic acid having a dimer structure and is a fatty acid dimer. The fatty acid dimer is preferably a compound with 20 to 60 carbon atoms, more preferably a compound with 24 to 56 carbon atoms, even more preferably a compound with 28 to 48 carbon atoms, and particularly preferably a compound with 36 to 44 carbon atoms. The fatty acid dimer is preferably a dicarboxylic acid compound having a branched structure obtained by a Diels-Alder reaction of a fatty acid. The branched structure is preferably a fatty acid chain or a ring structure, and more preferably a ring structure. The aforementioned ring structure is preferably one or more aromatic rings or an alicyclic structure, with an alicyclic structure being more preferable. The alicyclic structure may have one double bond within the ring, or it may not have a double bond.

[0038] Dimer amines are preferably compounds with 20 to 60 carbon atoms, more preferably compounds with 24 to 56 carbon atoms, even more preferably compounds with 28 to 48 carbon atoms, and even more preferably compounds with 36 to 44 carbon atoms. Dimer amines with such carbon number configurations are preferred from the viewpoint of availability.

[0039] Commercially available dimer amines include, for example, "Priamine 1071," "Priamine 1073," "Priamine 1074," and "Priamine 1075" from Croda Japan, and "Versamin 551" from BASF Japan. Dimer amines can be used alone or in combination of two or more types.

[0040] Polybasic acids having a dimer structure for obtaining dimer amines include, for example, the structures shown in chemical formulas (d1) to (d4) below. It goes without saying that polybasic acids having a dimer structure are not limited to the structures shown below.

[0041] [ka]

[0042] [ka]

[0043] [ka]

[0044] [ka]

[0045] A dimer structure is a molecular structure with minimal interaction between multiple hydrocarbon chains or ring structures. By incorporating a dimer structure into polyimide resin (A), internal stress generated within the heat-conductive insulating adhesive layer after curing can be relieved. This stress relief by the dimer structure in polyimide resin (A) suppresses the reduction in adhesive strength and crack formation caused by stress generated by repeated high and low temperature cycles. Therefore, heat resistance and moisture resistance can be effectively improved.

[0046] The content of the above-mentioned dimer amine is preferably 70 mol% or less, more preferably 15 to 55 mol%, and even more preferably 20 to 50 mol%, relative to 100 mol% of the polyamine compound used to synthesize the polyimide resin (A). By including dimer amine, the effect of inhibiting packing properties around the imide ring, which has high planarity due to the dimer structure, can be fully exhibited. When dimer amine is used at a concentration of 70 mol% or less, the polyimide resin (A) can exhibit flexibility, stress relaxation properties, and heat resistance after long-term heating.

[0047] Furthermore, the content of hydrocarbon groups with 20 to 60 carbon atoms derived from the dimer skeleton contained in the polyimide resin (A) is preferably 30 to 90% by mass. More preferably, it is 35 to 85% by mass, and even more preferably 40 to 70% by mass. By using 30 to 90% by mass, the effect of inhibiting the packing properties around the highly planar imide ring due to the dimer structure can be fully exhibited.

[0048] The polyimide resin (A) may be used in combination with other polyamine compounds, without departing from the spirit of the present invention. The other polyamine compounds are not particularly limited and can be aromatic or aliphatic, and may contain unsaturated bonds.

[0049] Other polyamine compounds are preferably substituents, with phenolic hydroxyl groups and carboxyl groups being preferred substituents. Aromatic diamine compounds having phenolic hydroxyl groups include 3,3'-diamino-4,4'-dihydroxydiphenyl sulfone, 3,3'-diamino-4,4'-dihydroxydiphenyl ether, 3,3'-diamino-4,4'-dihydroxybiphenyl, 3,3'-diamino-4,4'-dihydroxybenzophenone, 2,2-bis(3-amino-4-hydroxyphenyl)methane, 2,2-bis(3-amino-4-hydroxyphenyl)ethane, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and 9,9'-bis(3-amino-4-hydroxyphenyl)fluorene.

[0050] Examples of diamine compounds having a carboxyl group include monocyclic compounds such as 3,5-diaminobenzoic acid, 3,4-diaminobenzoic acid, 1,3-diamino-4,6-dicarboxybenzene, 1,2-diamino-4,6-dicarboxybenzene, and 1,3-diamino-4,5-dicarboxybenzene, as well as 5,5'-methylenebis(2-aminobenzoic acid), 3,3'-diamino-4,4'-dicarboxybiphenyl, and 4,4'-diamino-2,2',5,5'-tetracarboxybiphenyl. Examples include 4,4'-diamino-3,3'-dicarboxydiphenylmethane, 3,3'-diamino-4,4'-dicarboxydiphenylmethane, 4,4'-diamino-2,2',5,5'-tetracarboxydiphenyl ether, 3,3'-diamino-4,4'-dicarboxydiphenyl sulfone, 2,2-bis[4-(4-amino-3-carboxyphenyl)phenyl]propane, and 2,2-bis[4-(4-amino-3-carboxyphenoxy)phenyl]sulfone.

[0051] By using aromatic diamine compounds having phenolic hydroxyl groups and diamine compounds having carboxyl groups, phenolic hydroxyl groups and carboxyl groups can be introduced into the polyimide resin (A). By using the polyimide resin (A) having phenolic hydroxyl groups and carboxyl groups, the crosslinking points with the curing agent (B) can be adjusted, thereby adjusting the three-dimensional crosslinked structure and obtaining a tough cured product.

[0052] Examples of aromatic diamine compounds include diamine compounds having one aromatic ring in one molecule, diamine compounds having two or more independent aromatic rings in one molecule, and diamine compounds having a condensed aromatic ring in one molecule.

[0053] Examples of diamine compounds having one aromatic ring in one molecule include 1,4-phenylenediamine, 1,2-phenylenediamine, and 1,3-phenylenediamine.

[0054] Examples of diamine compounds having two or more independent aromatic rings within a single molecule include 4,4'-(biphenyl-2,5-diylbisoxy)bisaniline, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, bis(4-(4-aminophenoxy)phenyl)sulfone, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, and bis(4-(3-aminophenoxy)phenyl Examples include nyl(sulfone), 1,3-bis(4-aminophenoxy)neopentane, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenyl sulfide, N-(4-aminophenoxy)-4-aminobenzamine, bis(3-aminophenyl)sulfone, norbornanediamine, etc.

[0055] Examples of diamine compounds having a condensed aromatic ring within one molecule include 4,4'-(9-fluorenylidene)dianiline, 2,7-diaminofluorene, 1,5-diaminonaphthalene, and 3,7-diamino-2,8-dimethyldibenzothiophene 5,5-dioxide.

[0056] Examples of aliphatic diamine compounds include alicyclic diamine compounds and linear aliphatic diamine compounds.

[0057] Examples of alicyclic diamine compounds include 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and 4,4'-methylenebis(2-methylcyclohexylamine).

[0058] Examples of linear aliphatic diamine compounds include 1,2-ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-hexamethylenediamine, 1,5-diaminopentane, 1,10-diaminodecane, 1,2-diamino-2-methylpropane, 2,3-dimethyl-2,3-butanediamine, and 2-methyl-1,5-diaminopentane.

[0059] Examples of diamine compounds containing a fluorine atom include 4-fluoro-1,2-phenylenediamine, 4-fluoro-1,3-phenylenediamine, 3-trifluoromethyl-1,5-phenylenediamine, 4-trifluoromethyl-1,5-phenylenediamine, 4-trifluoromethyl-1,2-phenylenediamine, 2-trifluoromethyl-1,4-phenylenediamine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-diamino-2-(trifluoromethyl)diphenyl ether, 4,4'-diamino-2,2'-(trifluoromethyl)biphenyl, and 4,4'-diamino-2-methyl-2'-tri Examples include fluoromethyl biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis[4-{4-amino-2-(trifluoromethyl)phenoxy}phenyl]hexafluoropropane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(3-aminophenyl)hexafluoropropane, and 2,2-bis{4-(4-aminophenoxy)-3,5-dibromophenyl}hexafluoropropane.

[0060] Furthermore, polyamine compounds having three or more amino groups may be used. Examples of polyamine compounds having three or more amino groups include 1,2,4-triaminobenzene and 3,4,4'-triaminodiphenyl ether.

[0061] Among these, 4,4'-diamino-2,2'-(trifluoromethyl)biphenyl, 4,4'-diamino-2,2'-dimethylbiphenyl, and 2,2-bis(4-(4-aminophenoxy)phenyl)propane are preferred as other polyamine compounds because they offer improved adhesion and thermal conductivity. The content of other polyamine compounds is preferably 50 mol% or less, and more preferably 30 mol% or less, relative to 100 mol% of the polyamine compound.

[0062] (Weight average molecular weight) The weight-average molecular weight of the polyimide resin (A) is preferably in the range of 5,000 to 150,000. Considering the adhesiveness, dispersibility of the thermally conductive filler (C), moisture resistance, and heat resistance, it is preferably 6,000 to 150,000, more preferably 7,500 to 125,000, and even more preferably 10,000 to 100,000. When the weight-average molecular weight is in the range of 5,000 to 150,000, the resin exhibits excellent fluidity in the thermocompression bonding process, suppresses the generation of voids inside the cured product, and exhibits excellent cohesive strength as a cured product, resulting in sufficient adhesive strength and insulating properties.

[0063] [Hardening agent (B)] The curing agent (B) is a compound having two or more reactive functional groups in one molecule and capable of constructing a crosslinked structure. The curing agent (B) is one or more selected from epoxy compounds (b), isocyanate compounds, polycarbodiimide compounds, aziridine compounds, dicyandiamide compounds, aromatic diamine compounds and other amine compounds, phenolic compounds such as phenol novolac resins, organometallic compounds, etc. The curing agent (B) may be a low-molecular-weight compound or a high-molecular-weight compound.

[0064] The curing agent (B) may be a compound that crosslinks with other curing agents (B) upon heat, or a compound that crosslinks with the curing agent (B) and the polyimide resin (A). When crosslinking with the polyimide resin (A), the curing agent (B) may crosslink with the functional groups contained in the side chains and side groups of the polyimide resin (A), in addition to the acid anhydride groups of the polyimide resin (A). These may be combined in any way.

[0065] <Epoxy compound (b)> Epoxy compounds (b) refer to compounds having two or more epoxy groups in one molecule, and known compounds can be used. Examples include glycidyl ether type epoxy compounds, glycidylamine type epoxy compounds, glycidyl ester type epoxy compounds, and cyclic aliphatic (alicyclic) epoxy compounds.

[0066] Examples of glycidyl ether type epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, bisphenol AD ​​type epoxy compounds, cresol novolac type epoxy compounds, phenol novolac type epoxy compounds, α-naphthol novolac type epoxy compounds, bisphenol A type novolac type epoxy compounds, biphenyl novolac type epoxy compounds, dicyclopentadiene type epoxy compounds, tetrabrom bisphenol A type epoxy compounds, brominated phenol novolac type epoxy compounds, tris(glycidyloxyphenyl)methane, tetrakis(glycidyloxyphenyl)ethane, and the like.

[0067] Examples of glycidylamine-type epoxy compounds include tetraglycidyldiaminodiphenylmethane, triglycidylparaaminophenol, triglycidylmetaaminophenol, and tetraglycidylmetaxylylenediamine.

[0068] Examples of glycidyl ester type epoxy compounds include diglycidyl phthalate, diglycidyl hexahydrophthalate, and diglycidyl tetrahydrophthalate.

[0069] Examples of cyclic aliphatic (alicyclic) epoxy compounds include epoxycyclohexylmethyl-epoxycyclohexanecarboxylate and bis(epoxycyclohexyl)adipate. Liquid epoxy compounds can also be suitably used. Among these, those having functional groups other than epoxy groups are preferred. For example, hydroxyl groups, secondary amino groups, and tertiary amino groups can be cited as other functional groups. By using epoxy compounds (b) having such other functional groups in addition to two or more functional epoxy groups, the crosslinking density under predetermined curing conditions can be effectively increased, thereby improving heat resistance. Furthermore, since metal adhesion derived from hydroxyl and amino groups can be enhanced, good heat resistance and adhesion can be simultaneously satisfied.

[0070] The ratio (mass ratio) of polyimide resin (A) to curing agent (B) is preferably in the range of (A):(B) = 99:1 to 40:60, more preferably (A):(B) = 98:2 to 50:50, and even more preferably 95:5 to 60:40. The above ratio can be used to further improve heat resistance. The hardening agent (B) can be used alone or in combination of two or more types.

[0071] [Thermal conductive filler (C)] The insulating composition of this embodiment contains a thermally conductive filler (C). Furthermore, the thermally conductive filler (C) has a tap density of 0.4 g / cm³. 3 More than 2.3g / cm 3 It contains boron(c) nitride with a concentration of less than 0.4 g / cm³. Boron(c) nitride may be used alone as the thermally conductive filler (C), or in combination with other fillers. Tap density refers to the bulk density of the filler when the volume change of the filler ceases after the filler has been dispersed in a predetermined container and the container has been subjected to a tapping shock. It is determined as the mass per unit volume of powder in the vibrated container. Tap density can be measured in accordance with the method for measuring the bulk density of fine ceramic powder specified in JIS R1628:1997. Tap density is 0.4 g / cm³. 3 More than 2.3g / cm 3 By setting it to less than this, the dispersibility of the polyimide resin (A) can be significantly improved. As a result, it is possible to combine the seemingly contradictory properties of improved thermal conductivity due to increased filling density and strong adhesive strength.

[0072] The tap density of boron(C) nitride is 0.45 g / cm³. 3 Preferably, it is 0.5 g / cm³ or more. 3 It is more preferable that the value be greater than or equal to 0.6 g / cm³. 3 The above is even more preferable, 0.7 g / cm³ 3 The above is particularly preferable. The upper limit of the tap density is 2.3 g / cm³, which is the true density of boron nitride. 3 Since it is less than 1.4 g / cm³, and considering availability, the upper limit is 1.4 g / cm³. 3Preferably, and more preferably, 1.3 g / cm³ 3 And more preferably 1.2 g / cm³ 3 That is the case.

[0073] The thermally conductive filler (C) preferably has a thermal conductivity of 5 W / mK or higher, more preferably 10 W / mK or higher, and even more preferably 20 W / mK or higher. By setting it to 5 W / mK or higher, the thermal conductivity effect can be effectively enhanced.

[0074] The thermal conductive filler (C) is itself an insulator, and its volume resistivity is 1.0 × 10⁻⁶. 10 It is preferable that the density be Ω·cm or greater, and 1.0 × 10 12 It is more preferable that the value be Ω·cm or greater, and 1.0 × 10 14 It is even more preferable that the resistivity is Ω·cm or greater. 10 By setting the resistance to Ω·cm or higher, the insulating properties can be effectively enhanced.

[0075] Boron(c) nitride can be used as primary particles, or aggregates of primary particles may be used. It is preferable to use aggregates to increase thermal conductivity. Alternatively, boron nitride aggregates sintered by heating may be used. The shape of boron(c) nitride is not particularly limited, but examples include spherical, fibrous, needle-shaped, flake-shaped, and aggregates thereof. Since flaky boron nitride particles have anisotropic thermal conductivity, granulated bodies or aggregates of flaky primary particles are preferably used. By using boron nitride in the form of granulated bodies or aggregates thereof, good thermal conductivity can be achieved in the thickness direction of the thermosetting insulating adhesive sheet even after heating and pressurizing.

[0076] The average particle size D50 of boron nitride (c) is preferably 10 to 100 μm. More preferably 15 to 90 μm, and even more preferably 20 to 80 μm. By setting the particle size to 10 to 100 μm, it is possible to improve dispersibility in the insulating composition while increasing thermal conductivity. The average particle size D50 refers to the particle size at which the cumulative degree of the volume standard particle size distribution reaches 50%. Specifically, a laser diffraction particle size distribution analyzer (SALD-2200, manufactured by Shimadzu Corporation) was used as the measuring device, and WingSALD-2200 was used as the measurement control software.

[0077] The insulating composition of this embodiment is used as a cured product after thermal curing, as will be described later. In the cured product, the thermal conductive filler (C) may be dispersed in an unoriented manner or in an oriented manner. The thermal conductivity of the thermal conductive filler (C) may be isotropic or anisotropic. However, when used in the form of a sheet, for example, it is preferable that the thermal conductive filler (C) is continuously arranged without interruption in the direction in which heat is to be conducted in order to ensure excellent thermal conductivity. This allows for the formation of a heat conduction path through which heat is dissipated from the heat source.

[0078] Examples of boron nitride (c) include hexagonal boron nitride (hBN) and cubic boron nitride. Hexagonal boron nitride is more preferred. Hexagonal boron nitride has a plate-like particle shape and exhibits high thermal conductivity (typically around 400 W / m·K) in the direction of its plate surface (within the ab plane or (002) plane). Therefore, from the viewpoint of efficiently increasing thermal conductivity, it is preferable to use hexagonal boron nitride oriented in the direction in which the thermal conductivity is to be increased. Here, "oriented" includes orientations that can impart anisotropy to the thermal conductivity.

[0079] The content of the thermally conductive filler (C) relative to 100% by volume of the insulating composition in this embodiment can be appropriately designed depending on the application, but from the viewpoint of achieving better thermal conductivity and adhesion, it is preferable to set it to 50 to 70% by volume relative to 100% by volume of the composition excluding voids. More preferably it is 52.5 to 65% by volume, and even more preferably 55 to 62.5% by volume.

[0080] Furthermore, the content of boron nitride (c) relative to 100% by volume of thermal conductive filler (C) can be appropriately designed depending on the application, but it is preferable to set it to 40 to 100% by volume from the viewpoint of achieving better thermal conductivity and adhesion. More preferably it is 60 to 100% by volume, and even more preferably 70 to 100% by volume.

[0081] As a specific example of a thermally conductive filler (C) other than boron nitride (C), a tap density of 0.4 g / cm³ is used. 3 Examples include metal oxides such as boron nitride, titanium dioxide, aluminum oxide, aluminum nitride, aluminum hydroxide, silicon nitride, zinc oxide, titanium dioxide, beryllium oxide, magnesium oxide, nickel oxide, vanadium oxide, copper oxide, iron oxide, and silver oxide; and silicon compounds such as quartz powder, silicon carbide, silicon carbide, and mica.

[0082] The average particle size D50 of thermally conductive fillers (C) other than boron nitride (c) is preferably 0.1 μm or larger from the viewpoint of fully exhibiting the thermal conductivity effect. From the viewpoint of increasing the packing density when combined with boron nitride (c), particles with an average particle size D50 different from that of boron nitride may be used.

[0083] The thermally conductive filler (C) may be crushed / ground as needed before being mixed with the polyimide resin (A), etc. The surface of the thermally conductive filler (C) can be surface-treated with, for example, silane-based, titanate-based, and aluminate-based coupling agents. Surface treatment can improve the dispersibility of the thermally conductive filler (C) in the polyimide resin (A). It can also improve the interfacial adhesion strength between the polyimide resin (A) and the thermally conductive filler (C). A silane coupling agent is preferred as a surface treatment agent for silica filler.

[0084] Silane coupling agents are compounds having a hydrolyzable group and a reactive functional group. Examples of hydrolyzable groups include alkoxy groups having 1 to 6 carbon atoms, such as methoxy and ethoxy groups; acetoxy groups; and 2-methoxyethoxy groups. Among these, methoxy groups are preferred because they easily remove volatile components such as alcohols produced by hydrolysis. Examples of the reactive functional groups include vinyl groups, epoxy groups, styryl groups, methacrylic groups, acrylic groups, amino groups, ureido groups, mercapto groups, sulfide groups, and isocyanate groups, but epoxy groups are preferred among these.

[0085] Methods for treating silica fillers with a silane coupling agent include, for example, a wet method in which silica fillers and the silane coupling agent are mixed in a solvent, and a dry method in which silica fillers and the silane coupling agent are treated in the gas phase. Preferably, the amount of silane coupling agent used is about 0.1 to 1 part by mass of the silane coupling agent per 100 parts by mass of untreated silica fillers.

[0086] (Other fillers (D)) The insulating composition of this embodiment may contain other fillers (D) as optional components. Fillers (D) may be inorganic or organic fillers. Examples include silica fillers, talc, carbon nanotubes, and graphite. Depending on the desired properties such as flame retardancy, mechanical strength, heat resistance, and moisture absorption, one or more fillers may be used individually or in combination.

[0087] (Catalyst (E)) Furthermore, the insulating composition of this embodiment may contain a catalyst (E) as an optional component to promote crosslinking between the polyimide resin (A) and the curing agent (B). Examples of crosslinking sites between the polyimide resin (A) and the curing agent (B) include functional groups such as acid anhydride groups at the end of the molecular chain, and functional groups of the side chains and / or side groups. Examples of catalysts (E) include compounds having a tertiary amino group, phosphorus-based curing accelerators, urea compounds, dicyandiamide compounds, hydrazide compounds, etc. Compounds having a tertiary amino group, urea compounds, and dicyandiamides are more preferred, and compounds having a tertiary amino group are most preferred. Compounds having a tertiary amino group may have heterocyclic or non-heterocyclic forms, with heterocyclic forms being even more preferred. These may be used individually or in combination of two or more.

[0088] Among these, latent curing accelerators that are solid at room temperature and melt when a thermosetting insulating adhesive sheet is heated and pressurized to exhibit their function as a curing accelerator are preferred, and latent curing accelerators having a tertiary amino group are particularly preferred. Examples of latent curing accelerators having a tertiary amino group include adduct-type latent curing accelerators in which a relatively low molecular weight epoxy compound is added to a relatively low molecular weight compound that has a tertiary amino group and a functional group that can react with an epoxy group. Adduct-type latent curing accelerators having a tertiary amino group include those with a heterocycle, such as an imidazole group, and those without a heterocycle.

[0089] Examples of tertiary amine-adduct latent curing accelerators that do not have heterocyclic rings include Amicure MY-24, Amicure MY-25, Amicure MY-H, Amicure MY-24J, and Amicure MY-HK-1 from Ajinomoto Fine Techno Co., Ltd.; and EH4380S, EH3616S, EH5001P, EH4357S, and EH3615S from ADEKA Corporation.

[0090] Examples of heterocyclic imidazole-adduct latent curing accelerators include Amicure PN-23, Amicure PN-23J, Amicure PN-31, Amicure PN-31J, Amicure PN-40, Amicure PN-40J, Amicure PN-50, and Amicure PN-H from Ajinomoto Fine Techno Co., Ltd., Adeka Hardener EH3293S, Adeka Hardener EH3366S, and Adeka Hardener EH4346S from ADEKA Corporation, and Sanmide LH210 from Air Products Japan Co., Ltd.

[0091] Furthermore, other latent curing accelerators having tertiary amino groups besides adduct-type latent curing accelerators include: Dicyandiamide-modified polyamines (e.g., EH3842 manufactured by ADEKA Corporation), Urea-containing modified polyamines (for example, Fujicure FXE1000, Fujicure FXR1110, Fujicure FXR1121, Fujicure FXR1081, etc., manufactured by T&KTOKA Corporation), Urea-containing modified aliphatic polyamines (for example, EH4353S manufactured by ADEKA Corporation), Urea-bonded and imidazole-group-containing modified polyamines (e.g., FXR1110, FXR1121 manufactured by T&KTOKA Corporation), Other examples include imidazole compounds (for example, Cureazole SIZ, Cureazole 2MZ-H, Cureazole C11Z-CN, Cureazole C17Z, Cureazole 1.2DMZ, Cureazole 2E4MZ, Cureazole 2PZ, Cureazole 2PZ-PW, Cureazole 2MZ-A, Cureazole 2MA-OK, Cureazole 2PHZ, Cureazole 2P4MHZ, Cureazole 2MZ-CN, Cureazole C11Z-CN, Cureazole 2E4MZ-CN, Cureazole 2PZ-CN, etc., manufactured by Shikoku Chemicals, Inc.).

[0092] Examples of urea compounds include aromatic dimethylurea (e.g., U-CAT3512T from Sunapro Co., Ltd., and DYHARDUR200, UR300, and UR500 from Evonik), aliphatic dimethylurea (e.g., U-CAT3513N from Sunapro Co., Ltd.), 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, and 2,4-bis(3,3-dimethylureido)toluene, among other ureas.

[0093] Examples of hydrazide compounds include carbohydrazide, oxalate dihydrazide, malonic acid dihydrazide, succinate dihydrazide, iminodiacetate dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacate dihydrazide, dodecanedihydrazide, hexadecanedihydrazide, maleate dihydrazide, and fumarate dihydrazide. Examples of hydrazides include dihydrazide, diglycolic acid dihydrazide, tartrate dihydrazide, malate dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2,6-naphthoate dihydrazide, 4,4'-bisbenzene dihydrazide, 1,4-naphthoate dihydrazide, naphthalene-2,6-dicarbohydrazide, 3-hydroxy-2-naphthoate hydrazide, and citrate trihydrazide. Commercially available hydrazide compounds include, for example, Amicure VDH and Amicure UDH manufactured by Ajinomoto Fine Techno Co., Ltd.

[0094] Phosphorus-based curing accelerators include organophosphine compounds, such as first, second, and third organophosphine compounds like alkylphosphine, dialkylphosphine, trialkylphosphine, phenylphosphine, diphenylphosphine, and triphenylphosphine; phosphinoalkane compounds like (diphenylphosphine)methane, 1,2-bis(diphenylphosphine)ethane, and 1,4-(diphenylphosphine)butane; diphosphine compounds like triphenyldiphosphine; and triorganophosphines like triphenylphosphine-triphenylborane. Salts with riorganoborane, tetraorganophosphonium and tetraorganoborates such as tetraphenylphosphonium tetraphenylborate, first to third benzylphosphine, tris(p-methoxyphenyl)phosphine, tris(p-methylphenyl)phosphine, tricyclohexylphosphine, triphenyldiphosphine, tetrabutylphosphonium bromide, 40% aqueous solution of tetrabutylphosphonium hydroside, 40% solution of tetrabutylphosphonium acetate, tetraphenylphosphonium bromide, methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, n-butyltriphenylphosphonium bromide, methoxymethyltriphenylphosphonium chloride, benzyltriphenylphosphonium chloride, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-triborate, tri-tert-butylphosphonium tetraphenylborate, triphenylphosphine triphenylborate, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis Examples include (diphenylphosphino)butane, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(p-methoxyphenyl)phosphine, diphenylcyclohexylphosphine, tricyclohexylphosphine, tributylphosphine, tri-tert-butylphosphine, tri-n-octylphosphine, diphenylphosphinostyrene, diphenylphosphinochloride, tri-n-octylphosphine oxide, triphenylphosphine oxide, and diphenylphosphinylhydroquinone.

[0095] The ratio (mass ratio) of the curing agent (B) to the catalyst (E) is preferably (B):(E) = 50:50 to 99:1, more preferably 70:30 to 98:2, and even more preferably 60:40 to 96:4. By using the above ratio, the curing can be effectively accelerated while maintaining the pot life of the thermosetting insulating adhesive sheet.

[0096] (organic solvent) To adjust the viscosity of the insulating composition, an organic solvent may be included. The organic solvent is not particularly limited, and any known solvent may be selected as appropriate. Examples of organic solvents include toluene, xylene, methyl ethyl ketone, isopropyl alcohol, propylene glycol monomethyl ether, and cyclohexanone. These organic solvents can be used individually or in combination of two or more.

[0097] Furthermore, the insulating composition of this embodiment may further contain other additives without departing from the spirit of the present invention. For example, a polyimide resin other than polyimide resin (A) may be used. Any thermoplastic resin (elastomer) can also be used. Other examples include dyes, pigments (e.g., carbon black), flame retardants, antioxidants, polymerization inhibitors, defoaming agents, leveling agents, ion scavenging agents, humectants, viscosity modifiers, preservatives, antibacterial agents, antistatic agents, antiblocking agents, ultraviolet absorbers, infrared absorbers, electromagnetic shielding agents, and the like.

[0098] [Method for manufacturing an insulating composition]

[0099] The insulating composition is manufactured by stirring and mixing the polyimide resin (A) described above, a curing agent (B), a thermally conductive filler (C), and other optional components as needed. The polyimide resin (A) used is not a polyimide precursor, but rather imidized polyimide resin (A) as a compounding component. A solvent can be used as appropriate during compounding. The solid content concentration can be, for example, 20 to 60 parts by mass. Since the polyimide resin (A) of this embodiment has a siloxane structure, it can be easily dissolved in various organic solvents.

[0100] A general stirring method can be used for stirring and mixing. The stirring and mixing machine is not particularly limited, but examples include dispersers, mixers, kneaders, ScanDex machines, paint conditioners, sand mills, slag mixers, medialess dispersers, three-roll machines, and bead mills.

[0101] After stirring and mixing, it is preferable to go through a defoaming step to remove air bubbles from the insulating composition. The defoaming method is not particularly limited, but examples include vacuum defoaming and ultrasonic defoaming.

[0102] [Thermosetting insulating adhesive sheet] The thermosetting insulating adhesive sheet of this embodiment is formed from the insulating composition of the present invention. The thermosetting insulating adhesive sheet of this embodiment can be appropriately designed according to the application, but from the viewpoint of having a good balance of adhesiveness, heat resistance, moisture resistance, insulating properties and thermal conductivity, the porosity is preferably 45 volume% or less. More preferably 40 volume% or less, and even more preferably 35 volume% or less. The lower limit is not particularly limited, and the porosity may be 0 volume%. Herein, "porosity" refers to the value obtained by the method described in the examples below.

[0103] Furthermore, the thermosetting insulating adhesive sheet of this embodiment preferably contains 50 to 70 volume% of thermal conductive filler (C) per 100 volume% of the insulating composition excluding voids. More preferably, it contains 52.5 to 65 volume%, and even more preferably, 55 to 62.5 volume%. By including 50 to 70 volume% of thermal conductive filler (C), the thermal conductivity can be made even better. The "volume of thermal conductive filler (C) per 100 volume% of the composition excluding voids" as used herein refers to the value obtained by the method described in the examples below.

[0104] The thermosetting insulating adhesive sheet of the present invention can be obtained, for example, by the following method.

[0105] After applying the above-described insulating composition coating to the release treatment surface of the release sheet, the organic solvent is evaporated and dried to produce a thermosetting composition sheet with the release sheet attached. To accelerate the evaporation and drying of the organic solvent, heating may be performed at 60°C to 150°C for 30 seconds to 10 minutes, if necessary.

[0106] Examples of release sheets include plastic films such as polyester film, polyethylene film, polypropylene film, and polyimide film that have been treated with a release agent.

[0107] The method of coating the release sheet is not particularly limited, but examples include knife coating, blade coating, comma coating, die coating, lip coating, roll coating, curtain coating, bar coating, gravure coating, flexo coating, dip coating, spray coating, screen coating, dispenser, inkjet, and spin coating.

[0108] The thickness of the thermosetting composition sheet can be appropriately selected depending on the purpose, and from the viewpoint of film formation, it is preferably 50 μm to 450 μm.

[0109] To achieve a void ratio of 45 volume% or less in a thermosetting insulating adhesive sheet, two thermosetting composition sheets with release sheets are used, and the thermosetting composition sheets on the release sheets are overlapped and heat-pressed to form voids within the thermosetting composition sheets. By performing the heat-pressing under conditions of 60°C to 150°C and 0.1 to 3 MPa, the void ratio can be adjusted to 45 volume% or less. A known laminator or press can be used for the heat-pressing. Alternatively, a thermosetting insulating adhesive sheet sandwiched between release sheets can be obtained by overlapping a release sheet on the opposite side of a thermosetting composition sheet with a release sheet and similarly heat-pressing it.

[0110] When an insulating composition is molded into a desired shape such as a sheet, a portion of it may undergo a curing reaction, but this state, where further heating would allow it to harden, is not included in the definition of a cured product. The insulating composition may also be in a B-stage state, where some of its components are partially cured.

[0111] [Insulating adhesive layer] The insulating adhesive layer of this embodiment is the cured product after heat-pressing the thermosetting insulating adhesive sheet of this embodiment (the insulating adhesive layer is also referred to as the cured product). Preferably, the cured product has a porosity of 15 volume% or less than or equal to that of the product before curing. The porosity may be the same before and after curing. By setting the porosity to 15 volume% or less, the thermal conductivity, adhesiveness, and insulating properties can be exhibited more effectively. A more preferable range for the porosity is 12 volume% or less, and even more preferably 10 volume% or less. A known heating and pressing press can be used for heat-pressing. The heating and pressing press is not particularly limited, and a known press processing machine or laminator can be used. The temperature during heating and pressing can be appropriately selected, but it is desirable to heat to a temperature above the temperature at which the polyimide resin (A) and curing agent (B) undergo thermal curing. For example, by heating and pressing at a temperature of 120 to 200°C and a pressure of 1.0 to 15 MPa for 0.5 to 5 hours, the porosity of the insulating adhesive layer can be set to 15 volume% or less. Additionally, if necessary, pressure pressing may be performed under vacuum.

[0112] The thickness of the insulating adhesive layer in this embodiment can be appropriately designed depending on the application, but is preferably 50 to 250 μm. More preferably 60 to 225 μm, and even more preferably 70 to 200 μm.

[0113] [Composite material] The composite member of this embodiment comprises a heat-generating member capable of generating heat, a heat-dissipating base material that dissipates the heat from the heat-generating member, and an insulating adhesive layer that joins these together.

[0114] There are no particular restrictions on composite materials, but examples include various electronic components such as RF (radio frequency) modules, hybrid package modules, power transistor modules, power semiconductor modules, and LED (light-emitting diode) modules, as well as building materials, vehicles, aircraft, and ships, which tend to generate heat and require heat dissipation to prevent performance degradation.

[0115] (Heat dissipation base material) The heat dissipation base substrate of this embodiment is a component for releasing heat generated from a heat-generating element, which includes a heat-generating component, into the atmosphere. Known heat dissipation base substrates can be used in this invention.

[0116] The surface roughness of the heat dissipation base substrate is preferably 0.1 to 15 μm in terms of the ten-point average roughness Rz. By setting the Ra of the heat dissipation base substrate to 0.1 μm or more, adhesion with the insulating adhesive layer is improved due to the anchoring effect. By setting the surface roughness Ra of the heat dissipation base substrate to 15 μm or less, the height of the protrusions on the heat dissipation base substrate is suppressed, thereby improving insulation performance.

[0117] The heat dissipation base material is preferably made of metal or ceramic, and is not particularly limited. Examples include aluminum, copper, iron, tungsten, molybdenum, magnesium, copper-tungsten alloy, copper-molybdenum alloy, copper-tungsten-molybdenum alloy, aluminum nitride, silicon carbide, silicon nitride, graphene, and other carbon materials, which can be used alone or in combination of two or more.

[0118] The heat dissipation base substrate may be fitted with fins to improve heat dissipation efficiency. Known types of fins can be used. There are no particular limitations on the shape of the fins, but examples include straight fins, wavy fins, offset fins, pin fins, and corrugated fins, which can be appropriately selected depending on the intended use. Furthermore, the heat dissipation base substrate itself may be a fin.

[0119] (Heat-generating components that can produce heat) The heat-generating member (hereinafter also referred to as the heating element) of this embodiment may be the heating element alone, or a form in which the heating element is laminated on a conductive member such as a metal foil or metal plate via a bonding agent such as solder.

[0120] In addition to the same reasons explained for the heat dissipation base substrate, the surface roughness of the surface of the heating element and conductive member that comes into contact with the insulating adhesive layer is preferably 0.1 to 15 μm in terms of ten-point average roughness Rz, from the viewpoint of insulation, because electric charge tends to concentrate in narrow, pointed areas.

[0121] The heating element in this embodiment includes various electronic components such as integrated circuits, IC chips, hybrid packages, power transistors, power semiconductor elements, surface resistors, and LEDs (light-emitting diodes).

[0122] The insulating adhesive layer of the present invention can be suitably used in a power semiconductor module comprising a power semiconductor element and a heat dissipation base substrate. There are no particular restrictions on the form of the power semiconductor module, but generally, it is a laminate in which power semiconductor elements are laminated on a conductive member such as a metal plate via a bonding agent such as solder, and the laminate is further sealed with resin. By connecting the conductive member and the heat dissipation base substrate via the insulating adhesive layer, the heat generated when the power semiconductor module is driven is efficiently transferred to the heat dissipation base substrate, and heat is dissipated.

[0123] Examples of conductive materials used in power semiconductor modules include metals such as silver, copper, aluminum, nickel, tin, iron, and lead, as well as their alloys and carbon, and may have circuit patterns formed on them. These may be laminated on a resin or ceramic.

[0124] The conductive member is laminated between the power semiconductor element and the insulating adhesive layer, and also plays a role in transferring heat generated by the power semiconductor to the insulating adhesive layer. As a result, heat is effectively transferred to the heat dissipation base substrate, and heat dissipation from the power semiconductor element is promoted. [Examples]

[0125] The present invention will be described in more detail below with reference to examples, but these examples do not limit the scope of the present invention in any way. Unless otherwise specified, "parts" and "%" in the examples refer to "parts by mass" and "mass%", respectively.

[0126] <Solid content concentration> The solid content concentration of the resin was measured in accordance with JIS K5601-1-2, using the residual content after heating at a heating temperature of 150°C for 20 minutes.

[0127] <Measurement of weight-average molecular weight (Mw)> Mw was measured using the HPC-8020 GPC (gel permeation chromatography) system manufactured by Tosoh Corporation. GPC is a liquid chromatography system that separates and quantifies substances dissolved in a solvent (THF: tetrahydrofuran) based on the difference in their molecular size. In this invention, the measurement was performed using two LF-604 columns (Showa Denko Corporation: rapid analysis GPC column: 6mm ID × 150mm size) connected in series, under conditions of a flow rate of 0.6 mL / min and a column temperature of 40°C, and the weight-average molecular weight (Mw) was determined in terms of polystyrene equivalent.

[0128] <Measurement of Acid Value> Precisely weigh approximately 1 g of the sample into a stoppered Erlenmeyer flask and dissolve it in 100 mL of cyclohexanone solvent. Add phenolphthalein reagent as an indicator and hold for 30 seconds. Then, titrate with 0.1 N alcoholic potassium hydroxide solution until the solution turns pale pink. The acid value was determined by the following formula (unit: mgKOH / g). Acid value (mgKOH / g)=(5.611×a×F) / S however, S: Sample volume (g) a: Consumption volume (mL) of 0.1N alcoholic potassium hydroxide solution F: Titer of 0.1N alcoholic potassium hydroxide solution

[0129] <Measuring amine titer> Precisely weigh approximately 1 g of the sample into a stoppered Erlenmeyer flask and dissolve it in 100 mL of cyclohexanone solvent. Add 2-3 drops of an indicator prepared by mixing 0.20 g of methyl orange dissolved in 50 mL of distilled water and 0.28 g of xylene cyanol FF dissolved in 50 mL of methanol, and hold for 30 seconds. Then, titrate with 0.1 N alcoholic hydrochloric acid solution until the solution turns bluish-gray. The amine value was determined by the following formula (unit: mgKOH / g). Amine value (mgKOH / g) = (5.611 × a × F) / S however, S: Sample volume (g) a: Amount of 0.1N alcoholic hydrochloric acid solution consumed (mL) F: Potency of 0.1N alcoholic hydrochloric acid solution

[0130] <Manufacturing of polyimide resin> [Manufacturing Example 1: Polyimide resin (A)-1 solution] In a reaction vessel equipped with a gas inlet tube, thermometer, condenser, and stirrer, 100 parts of s-BPDA, 472.30 parts of X-22-161A, 9.39 parts of MBAA, and 581.69 parts of cyclohexanone were charged, and the vessel was purged with nitrogen gas. The reaction vessel was heated to 120°C while stirring and stirred for 2 hours, then the temperature was raised to 150°C and stirred for 8 hours. After the reaction was complete, all solvent was removed under reduced pressure. The mixture was then cooled to 100°C, toluene was added, and a polyimide resin (A)-1 solution with Mw 44000, acid value 6.27 mgKOH / g, and amine value 0.80 mgKOH / g was obtained (non-volatile content 50%).

[0131] [Manufacturing Examples 2-22: Polyimide resin (A)-2-(A)-22 solution] Except for changing the compound composition shown in Tables 1-1 to 1-3, the same procedure as in Production Example 1 was performed to obtain polyimide resin (A)-2 to (A)-22 solutions.

[0132] [Table 1-1]

[0133] [Table 1-2]

[0134] [Table 1-3]

[0135] The abbreviations used in Table 1 are shown below. s-BPDA: 3,3',4,4'-biphenyltetracarboxylic acid dianhydride OPDA: 4,4'-Oxydiphthalic anhydride PMDA: Pyromellitic dianhydride TDA: 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride Priamine 1075: Dimer amine, product name "PRIAMINE 1075", manufactured by Croda Japan Co., Ltd. KF-8010: Diaminopolysiloxane, product name "KF-8010", manufactured by Shin-Etsu Chemical Co., Ltd. X-22-161A: Diaminopolysiloxane, product name "X-22-161A", manufactured by Shin-Etsu Chemical Co., Ltd. MBAA: 5,5'-Methylenebis(2-aminobenzoic acid), product name "MBAA", manufactured by Seika Corporation. m-TB-HG: 4,4'-diamino-2,2'-dimethylbiphenyl, product name "m-TB-HG", manufactured by Seika Corporation.

[0136] [Polyimide resin P1] In accordance with Example 1 disclosed in Patent Document 2, ODPA and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane were reacted to obtain a solution of polyimide resin P1 with Mw 26000, acid value 0.20 mg KOH / g, amine value 7.20 mg KOH / g, and no siloxane structure (non-volatile content approximately 30%).

[0137] [Dimer acid polyamide-imide resin P2] A solution of dimer acid polyamide-imide resin P2 was obtained according to synthesis example PAI-1 disclosed in the examples of Patent Document 1 mentioned above. Specifically, by reacting dimer acid (Harima Chemicals, Haridaimer 250 (molecular weight 580, 36 carbon atoms, 80% by weight dimer acid content)), 1,3-bis(3-aminopropyl)tetramethyldisiloxane, 4,9-dioxadodecane-1,12-diamine, and 4,4'-oxydiphthalic acid n-dianhydride), a solution of dimer acid polyamide-imide resin P2 containing a siloxane structure was obtained, with an Mw of 23,800, an acid value of 9.50 mgKOH / g, and an amine value of 1.60 mgKOH / g (non-volatile content approximately 50%).

[0138] [Example 1] Preparation of insulating composition and thermosetting insulating adhesive sheet A solution containing 17.13 parts of polyimide resin (A)-1 obtained in Production Example 1 was mixed with a solution containing 2.59 parts of the curing agent (B), epoxy resin "jER152" manufactured by Mitsubishi Chemical Corporation, 3.43 parts of epoxy resin "jER1256" manufactured by Mitsubishi Chemical Corporation, and 0.13 parts of C11Z-CN manufactured by Shikoku Chemicals, Inc. Next, the thermally conductive filler (C) was boron nitride (c) HP40-MF100 (boron nitride particles, tap density 0.85 g / cm³). 3 An insulating composition was obtained by adding 76.73 parts of (average particle size D50: 35 μm, manufactured by Mizushima Iron Alloy Co., Ltd.) and toluene, and stirring with a disperser to adjust the non-volatile content to 50% by mass. Note that the above blending amount refers to the amount of solid content.

[0139] Two thermosetting composition sheets, each 100 μm thick and covered on one side by the release sheet, were prepared by coating the obtained insulating composition onto a release sheet using an applicator and drying. These two thermosetting composition sheets were then overlapped so that they bonded together, and heated and compressed under conditions of 100°C, 0.3 MPa, and 1 m / min to obtain the thermosetting insulating adhesive sheet of Example 1, sandwiched between the two release sheets. The thickness of this thermosetting insulating adhesive sheet was 190 μm. This thermosetting insulating adhesive sheet theoretically contained 70 volume% boron(c) nitride and had a porosity of 36 volume%. The porosity, heat dissipation, adhesive strength, insulation, solder reflow resistance, and flexibility after long-term heating of the cured thermosetting insulating adhesive sheet were evaluated according to the methods described later.

[0140] <Method for calculating the volume content of thermally conductive filler (C)> The true density of HP40-MF100, which is boron nitride (c) used as the thermally conductive filler (C) in Example 1, is 2.3 g / cm³. 3 Therefore, the volume occupied by the 76.73g of thermal conductive filler (C) contained in 100g of thermosetting insulating adhesive sheet is 33.36cm³. 3 Similarly, the true density of polyimide resin (A)-1 is 1 g / cm³. 3 True density of jER152: 1.22 g / cm³ 3True density of jER1256: 1.19 g / cm³ 3 True density of C11-Z: 0.92 g / cm³ 3 Therefore, the volume occupied by 17.13g of polyimide resin (A)-1, 2.59g of jER152, 3.43g of jER1256, and 0.13g of 2P4MZ in 100g of thermosetting insulating adhesive sheet is 17.13cm³ each. 3 , 2.12cm 3 , approx. 2.88cm 3 , 0.14cm 3 Therefore, the volume content of the thermally conductive filler (C) contained in the thermosetting insulating adhesive sheet can be determined to be 60 volume%. The true density of the polyimide resins (A)-2 to (A)-22 and P1 to P3 is 1 g / cm³. 3 The true densities of other compounds will be discussed later.

[0141] [Examples 2-42], [Comparative Examples 1-5] In accordance with the formulations shown in Tables 2-1 to 2-3, insulating compositions and thermosetting insulating adhesive sheets with release sheets were obtained and evaluated in the same manner as in Example 1.

[0142] The components in Tables 2-1 to 2-3 are as follows: (Hardening agent (B)) jER828 (product name): Epoxy compound (b), bisphenol A type epoxy compound, epoxy equivalent = 186 g / eq, true density is 1.16 g / cm³. 3 , manufactured by Mitsubishi Chemical Corporation jER152 (product name): Epoxy compound (b), phenol novolac type epoxy compound, epoxy equivalent = 174 g / eq, true density is 1.22 g / cm³. 3 , manufactured by Mitsubishi Chemical Corporation jER1256 (product name): Epoxy compound (b), bisphenol A type epoxy compound, epoxy equivalent = 7800 g / eq, true density is 1.19 g / cm³. 3 Manufactured by Mitsubishi Chemical Corporation jERYX6954BH30 (Product Name): Epoxy compound (b), modified biphenol type epoxy compound, epoxy equivalent = 13000 g / eq, methyl ketone / cyclohexanone solution, non-volatile content 35% by mass, true density 1.19 g / cm³ 3 , manufactured by Mitsubishi Chemical Corporation (Catalyst (E)) C11Z-CN (Product Name): Manufactured by Shikoku Chemicals Co., Ltd., true density is 0.92 g / cm³. 3 (Thermal conductive filler (C)) HP40-MF100 (Product Name): Boron(C) nitride, manufactured by Mizushima Iron Alloy Co., Ltd., tap density 0.85 g / cm³ 3 The average particle size D50 is 35 μm, and the true density is 2.3 g / cm³. 3 . SGPS (Product Name): Boron(c) Nitride, manufactured by Denka Co., Ltd., tap density 0.50 g / cm³ 3 The average particle size D50 is 12 μm, and the true density is 2.3 g / cm³. 3 . TECO20202022 (Product Name): Boron(c) Nitride, manufactured by MMOMENTIVE, tap density 0.92 g / cm³ 3 The average particle size D50 is 40 μm, and the true density is 2.3 g / cm³. 3 . PTX25 (product name): Boron nitride other than (c), manufactured by MOMENTIVE, tap density 0.30 g / cm³ 3 The average particle size D50 is 12 μm, and the true density is 2.3 g / cm³. 3 . HP-P1 (Product Name): Boron nitride other than (c), manufactured by Mizushima Ferroalloy Co., Ltd., tap density 0.38 g / cm³ 3 The average particle size D50 is 3 μm, and the true density is 2.3 g / cm³. 3 . AO-502 (Product Name): Alumina, manufactured by Admatex Co., Ltd., average particle size D50 is 0.2 μm, true density is 3.9 g / cm³. 3 . AA3 (Product Name): Alumina, manufactured by Sumitomo Chemical Co., Ltd., average particle size D50 is 3 μm, true density is 3.9 g / cm³. 3 . AA07 (Product Name): Alumina, manufactured by Sumitomo Chemical Co., Ltd., average particle size D50 is 0.7 μm, true density is 3.9 g / cm³. 3 . JR301 (Product Name): Titanium dioxide, manufactured by Teika Co., Ltd., average particle size D50 is 0.3 μm, true density is 4.2 g / cm³. 3 .

[0143] [Example 43] The insulating composition of Example 4 was applied to a release sheet using an applicator and dried to obtain a thermosetting composition sheet with a thickness of 200 μm, with one side covered by the release sheet. Subsequently, under conditions of 100°C, 0.3 MPa, and 1 m / min, a release sheet was laminated to the surface (coated side) of the thermosetting composition sheet to obtain the thermosetting insulating adhesive sheet of Example 42, which was sandwiched between two release sheets. This thermosetting insulating adhesive sheet had a thickness of 190 μm, theoretically contained 60 volume% boron(c) nitride, and had a porosity of 35 volume%. The porosity, heat dissipation, adhesive strength, insulating properties, solder reflow resistance, and flexibility after long-term heating of the cured thermosetting insulating adhesive sheet were evaluated according to the method described later.

[0144] [Table 2-1]

[0145] [Table 2-2]

[0146] [Table 2-3]

[0147] Table 3 shows the porosity of the thermosetting insulating adhesive sheets and the cured product for each example and comparative example. Table 3 also shows the evaluation results for heat dissipation, adhesive strength before PCT testing, adhesive strength after PCT testing, insulation, and heat resistance (solder reflow resistance) for each example and comparative example. The measurement methods and evaluation criteria are as follows.

[0148] <Void ratio of thermosetting insulating adhesive sheets> The porosity of a thermosetting insulating adhesive sheet is determined from the theoretical density and the measured density. The theoretical density is determined as follows. Theoretical density = Mass of thermosetting insulating adhesive sheet (g) / Volume of thermosetting insulating adhesive sheet (cm³) 3 ) =(17.13+2.59+3.43+0.13+76.73) / {(17.13 / 1)+(2.59 / 1.21)+(3.43 / 1.19)+(0.13 / 0.92)+(76.73 / 2.3)} This equals 1.80.

[0149] Furthermore, the measured density is determined as follows: The thermosetting insulating adhesive sheet, from which the release sheets on both sides have been peeled off, is cut to a size of 10 cm x 10 cm, and the mass of the thermosetting insulating adhesive sheet is determined. In Example 1, the mass was 2.189 g. Measured density = Mass of thermosetting insulating adhesive sheet (g) / Volume of thermosetting insulating adhesive sheet (cm³) 3 = 2.189 / (10 × 10 × 0.019) = 1.152.

[0150] The void ratio of a thermosetting insulating adhesive sheet can be calculated using the formula: void ratio = (1 - (measured density / theoretical density)) × 100. In the case of Example 1, the void ratio is: (1 - (Measured density / Theoretical density)) × 100 =(1-(1.152 / 1.80))=36% by volume.

[0151] <Porosity of hardened material> In each example and comparative example, a thermosetting insulating adhesive sheet (10 cm x 10 cm in size) with both sides sandwiched between release sheets was heated and pressed at 180°C and 3.0 MPa for 60 minutes, and the size in plan view after heating and pressing was confirmed. Next, the release sheets on both sides were peeled off, and the void ratio of the cured product was determined in the same manner as for the thermosetting insulating adhesive sheet. For example, in Example 1, during heat bonding, the cured material did not protrude from the release sheet, the size in plan view was the same as before heat bonding (10 cm × 10 cm), and a cured material with a thickness of 127 μm was obtained. The mass of the sheet after curing was 2.189 g, so the measured density of the cured material was: = 2.189 / (10 × 10 × 0.0127) = 1.724. Therefore, the void ratio of the hardened material is (1 - (Measured density / Theoretical density)) × 100 =(1-(1.724 / 1.80))×100=4% by volume. Furthermore, if any cured material spills out from the release sheet during heat bonding, the spilled portion should be removed, and the mass of a 10cm x 10cm area of ​​cured material should be measured and calculated.

[0152] <Heat dissipation (thermal conductivity)> Thermal conductivity is calculated from thermal diffusivity, specific heat, and density according to the following formula. Thermal conductivity (W / m·K) = Density (g / cm³) 3 ) × Specific heat (J / kg·K) × Thermal diffusivity (mm 2 / s) The thermal diffusivity was determined as follows: A thermosetting insulating adhesive sheet (10cm x 10cm in size), sandwiched between two release sheets, was heated and pressed at 180°C and 3.0 MPa for 60 minutes, and the release sheets were peeled off from both sides. The resulting cured material was cut into 20mm squares, gold vapor deposition was applied to the cured material, and then it was further coated with carbon spray. Next, the thermal diffusivity was measured using a xenon flash analyzer LFA447Nano Flash (NETZSCH). The measurement environment was 25±1°C, measurement voltage 202kV, Amplitude 2520, and pulse width 14ms. Furthermore, specific heat was measured using a high-sensitivity differential scanning calorimeter DSC220C manufactured by SII Nanotechnology Co., Ltd. The heating rate was 5°C / min, ranging from -50°C to 200°C, and the specific heat at 25°C was read. In addition, density was calculated using the water displacement method. The determined thermal conductivity was judged according to the following criteria. +++···The thermal conductivity is 8 W / m·K or higher. ++···The thermal conductivity is 5 W / m·K or more and less than 8 W / m·K. +···The thermal conductivity is 2 W / m·K or more and less than 5 W / m·K. NG···The thermal conductivity is less than 2 W / m·K. It is not suitable for practical use.

[0153] <Adhesive strength> A thermosetting insulating adhesive sheet sandwiched between release sheets on both sides was cut into a size of 65 mm × 65 mm. Also, two copper foils with a thickness of 35 μm and the same size [「Rolled Copper Foil CF-T8G-UN-35」manufactured by Fukuda Metal Co., Ltd.] were prepared. Then, the release sheets on both sides of the thermosetting insulating adhesive sheet were removed, and the copper foils were temporarily adhered sequentially under the conditions of 100 °C, 0.3 MPa, and 1 m / min, and then heat-pressed at 180 °C and 3.0 MPa for 60 minutes to perform a curing treatment. A test piece with a width of 10 mm and a length of 65 mm was cut out from the obtained copper foil / hardened product / copper foil laminate, and a 90-degree peel test was performed at a pulling speed of 500 mm / min in an environment of a temperature of 25 °C and a humidity of 50%RH, and the adhesive strength (N / cm) was measured. This test evaluates the adhesive strength of the hardened product of the thermosetting insulating adhesive sheet during normal temperature use. It was evaluated according to the following criteria. +++···The adhesive strength is 5 N / cm or more. ++···The adhesive strength is 3.5 N / cm or more and less than 5 N / cm. +···The adhesive strength is 1 N / cm or more and less than 3.5 N / cm. NG···The adhesive strength is less than 1 N / cm. It is not suitable for practical use.

[0154] <Adhesive strength before and after PCT test> A test piece with a width of 10 mm and a length of 65 mm was cut out from the copper foil / hardened product / copper foil laminate prepared in the same manner as the measurement of the above adhesive strength, and a pressure cooker test (PCT test) was performed at a temperature of 121 °C and a humidity of 100%RH for 48 hours. Using the test pieces before and after the PCT test, a 90-degree peel test was performed at a pulling speed of 500 mm / min in an environment of a temperature of 25 °C and a humidity of 50%RH, and the adhesive strength (N / cm) was measured. This test evaluated the adhesive strength of a thermosetting insulating adhesive sheet at room temperature, and the results were judged according to the following criteria. +++···The adhesive strength is 5 N / cm or more. ++···The adhesive strength is 3.5 N / cm or more and less than 5 N / cm. +...The adhesive strength is 1 N / cm or more and less than 3.5 N / cm. NG... The adhesive strength is less than 1 N / cm. Not suitable for practical use.

[0155] <Insulating properties> A 40mm x 40mm, 2mm thick copper block (C1020P(1 / 2H)), a thermosetting insulating adhesive sheet (40mm x 40mm) with the release sheets removed from both sides, and a 40mm x 40mm, 2mm thick aluminum block (A3003P(H24)) were prepared. These were laminated to form a copper block / thermosetting insulating adhesive sheet / aluminum block configuration and heated and pressed together at 180°C and 3.0 MPa for 60 minutes. The central 20mmφ of the copper block was masked with polyimide tape, etched using ferric chloride solution, and the polyimide tape was removed to prepare a sample with the central 20mmφ of the copper block remaining.

[0156] The samples obtained above were left to stand overnight in an environment of 25°C and 50% RH. Then, using a "20kV AC 7373" ultra-high voltage withstand voltage tester manufactured by Keisoku Gijutsu Kenkyusho Co., Ltd., the aluminum block was grounded, and the samples were immersed in a fluorine-based inert liquid (Fluorinert FC-3283, manufactured by 3M Japan). The voltage was increased from 0kV to 10kV at a rate of 1000V / sec, with a threshold current of 2mA. The voltage at which dielectric breakdown occurred was read and defined as the dielectric breakdown voltage. ++···The dielectric breakdown voltage is 4kV or higher. +...The dielectric breakdown voltage is 1kV or higher and less than 4kV. NG... Dielectric breakdown voltage is less than 1kV. Not suitable for practical use.

[0157] <Solder reflow resistance> Copper blocks, aluminum blocks, and thermosetting insulating adhesive sheets were prepared in the same manner as in the insulation test. These were stacked in the configuration of copper block / thermosetting insulating adhesive sheet / aluminum block, and then heat-pressed together at 180°C and 3.0 MPa for 60 minutes to create the test pieces. Using a solder reflow oven, the temperature program was set to maintain a peak temperature of 300°C for 5 minutes. The test piece was then transported into the oven, and the test piece was observed after exiting the oven. The evaluation criteria were as follows: ++···Out of 20 test pieces, delamination occurred in 2 or fewer. +...Of the 20 test pieces, the number of pieces with delamination was more than 2 but less than 5. NG... More than 5 out of 20 test pieces showed delamination. Not suitable for practical use.

[0158] <Flexibility after prolonged heating> A thermosetting insulating adhesive sheet (10cm x 10cm in size), sandwiched between two release sheets, was heated and compressed at 180°C and 3.0 MPa for 60 minutes to cure, and the release sheets on both sides were removed. Next, the cured material was cut into 100mm wide and 50mm long test specimens. After heat treatment of the test specimens at 180°C for 1000 hours, a 90-degree bending test was performed using a Toyo Seiki Seisakusho "Mandrel Bending Tester" with a 23mm diameter mandrel, in accordance with JIS K56005 1 (Flexural Resistance (Cylindrical Mandrel)), and the bending portion of the test specimen was observed. The evaluation criteria were as follows. ++···Of the 20 test specimens, two or fewer showed cracking. +...Of the 20 test specimens, more than 2 but 5 or fewer cracks occurred. NG... More than 5 out of 20 test specimens showed cracking. Not suitable for practical use.

[0159] [Table 3]

[0160] As shown in Table 3, in Comparative Examples 1 and 4, which used polyimide resins without a siloxane structure, the adhesive strength after PCT testing, solder reflow resistance, and flexibility after long-term heating were insufficient. Furthermore, the tap density was 0.4 g / cm³ compared to the polyimide resin with a siloxane backbone. 3 In Comparative Examples 2 and 5, which used boron nitride of less than 50, the heat dissipation was insufficient, and in Comparative Example 3, the adhesive strength before and after the PCT test was insufficient. In contrast, the insulating composition according to this example was found to have excellent heat dissipation, excellent adhesive strength both before and after the PCT test, and further excellent insulation, solder reflow resistance, and flexibility after long-term heating. [Industrial applicability]

[0161] The insulating composition of this embodiment exhibits excellent adhesion after curing and can therefore be used as an adhesive material. Furthermore, due to its excellent electrical insulation properties, it is suitably used as an insulating layer forming material on the circuit board itself or on the circuit board (including coverlay layers of printed wiring boards, interlayer insulating layers such as built-up substrates, substrate forming materials, bonding sheets, etc.), resin casting materials such as underfill materials, encapsulation materials for semiconductor chips, and materials for forming insulating layers of semiconductor chip packages. It is also suitable as a joining material between components, such as electronic circuit boards and electronic components. Moreover, its excellent thermal conductivity makes it applicable to a wide range of applications requiring heat dissipation. For example, its moldability allows it to be suitably used as a heat dissipation component of a desired shape. In particular, it is useful as a heat dissipation member for electronic devices (smartphones, tablet terminals, etc.) where fans or heat sinks cannot be installed due to the need for miniaturization and lightness, and for battery casings. Additionally, the cured product of the insulating composition of this embodiment is suitable as an adhesive layer or heat spreader between a heating element and a heat sink. It can also be applied as a heat dissipation layer covering one or more electronic components mounted on a substrate. Furthermore, it can be suitably used as an insulating heat dissipation sheet or molded product for dissipating heat generated from display devices such as liquid crystal displays and plasma display panels, and heat-generating components such as LEDs, to the outside. The insulating composition of the present invention exhibits excellent heat dissipation, excellent adhesive strength both before and after PCT testing, excellent insulating properties and heat resistance (solder reflow resistance), and excellent flexibility after prolonged heating. Therefore, it can be widely used in electronic equipment such as home appliances, industrial robots, and transportation equipment, as well as power semiconductor modules, building materials, vehicles, aircraft, and ships, where these properties are required.

Claims

1. The material contains a polyimide resin (A), which is a reaction product of a tetracarboxylic dianhydride and a polyamine compound containing siloxanediamine, a curing agent (B), and a thermally conductive filler (C), wherein the thermally conductive filler (C) has a tap density of 0.5 g / cm³. ３ Above, 2.3g / cm ３ An insulating composition containing boron(c) nitride in a quantity less than 1.

2. The tetracarboxylic dianhydride is defined by general formula (1): 【Chemistry 1】 (X １ (This is a tetravalent residue of a tetracarboxylic acid, having at least one substituted or unsubstituted aromatic ring.) The insulating composition according to claim 1, comprising a compound represented by .

3. The siloxanediamine mentioned above has the general formula (2): 【Chemistry 2】 (In general formula (2), R １ R indicates a divalent hydrocarbon group, ２ Each of these independently represents a monovalent hydrocarbon group, n １ (This represents an integer between 1 and 300.) The insulating composition according to claim 1 or 2, comprising at least one compound represented by .

4. The insulating composition according to any one of claims 1 to 3, comprising 10 to 80 mol% of the siloxanediamine in 100 mol% of the polyamine compound.

5. The insulating composition according to any one of claims 1 to 4, comprising 70 mol% or less of dimeramine in 100 mol% of the polyamine compound.

6. The insulating composition according to any one of claims 1 to 5, wherein the weight-average molecular weight of the polyimide resin (A) is 5,000 to 150,000.

7. The insulating composition according to any one of claims 1 to 6, wherein the curing agent (B) comprises an epoxy compound (b).

8. The insulating composition according to any one of claims 1 to 7, wherein the average particle size D50 of the boron nitride (c) is 10 to 100 μm.

9. The insulating composition according to any one of claims 1 to 8, wherein the amount of boron nitride (c) contained in 100% by volume of thermally conductive filler (C) is 40 to 100% by volume.

10. A thermosetting insulating adhesive sheet formed from an insulating composition according to any one of claims 1 to 9.

11. The thermosetting insulating adhesive sheet according to claim 10, wherein the porosity is 45 volume% or less, and the sheet contains 50 to 70 volume% of a thermally conductive filler (C) per 100 volume% of the insulating composition excluding voids.

12. An insulating adhesive layer obtained by heating and pressing a thermosetting insulating sheet according to claim 11 at a temperature of 120 to 200°C and a pressure of 1 to 15 MPa and then heat-curing it, wherein the porosity is 15 volume% or less.

13. The insulating adhesive layer according to claim 12, wherein the thickness is 50 to 250 μm.

14. A heat-generating component capable of generating heat, A heat dissipation base substrate for dissipating heat from the heat-generating member, A composite member having an insulating adhesive layer according to claim 12 or 13 for joining the heat-generating member and the heat-dissipating base substrate.

15. A portion of the surface of the heat-generating member is formed of copper or aluminum, and the copper or aluminum and the heat-conducting adhesive layer are directly bonded together. The composite member according to claim 14, wherein the heat dissipation base substrate is copper or aluminum.

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