Resin composition, resin-coated metal foil, cured product, metal base substrate, and electronic component

Abstract

[Problem] The present invention addresses the problem of finding: an electrical insulating layer for a metal base substrate used for electronic devices, in particular on-board electronic devices, the electrical insulating layer having a high electrical insulating capacity, high heat conductivity, low elasticity, and high resistance to soldering heat; and a resin composition which is the pre-curing form of the electrical insulating layer, the resin composition exhibiting good workability when applied to a body to be coated. [Solution] The problem is solved by providing: a heat-curable resin composition, a cured product, and a metal foil with a resin, which are characterized by containing (A) a rubber-like polymeric compound having a glass transition temperature (Tg) of -40֯C or less, and a weight average molecular weight (Mw) of 8,000-50,000, (B) an epoxy resin, (C) a filler, and (D) a phenoxy resin; a method for producing a metal base substrate having the foregoing; and a method for producing electronic parts using said metal base substrate. [Selected drawing] FIG. 1

Description

[Technical Field]

[0001] The present invention relates to a resin composition capable of forming an insulating layer having excellent electrical insulation and thermal conductivity, for use in, for example, electronic components, etc. The present invention also relates to a cured product of the resin composition, a metal base substrate having the cured product, a method for producing a metal base substrate by bonding a metal foil onto the cured product of the metal base substrate using a roll lamination method or a lamination press method, a resin-coated metal foil having the resin composition as a resin layer on a metal foil or a metal foil with a carrier, a method for producing a metal base substrate by overlaying the resin layer side of the resin-coated metal foil on a metal substrate and heating and pressurizing it in a vacuum press, and a method for producing an electronic component using the cured product or the metal base substrate. [Background technology]

[0002] In recent years, the miniaturization and increased density of electrical and electronic devices, such as home appliances, office automation equipment, and in-vehicle electronic devices, have led to concerns about increased heat generation from electronic components. This is because the generated heat has an undesirable effect on the performance and lifespan of the device. For this reason, metal-based substrates, which have at least an electrically insulating layer on a metal substrate with good thermal conductivity such as aluminum, copper, or iron, can be used as substrates for electronic circuits to efficiently dissipate the generated heat.

[0003] Although metal-based substrates have better heat dissipation properties, they are more expensive than general PCB substrates, and so have traditionally been used only for special substrates such as those for high voltage or high current applications. However, in recent years, with the increasing popularity of high-brightness LED headlights and power devices such as SiC, metal-based substrates are beginning to be adopted because they are cheaper than ceramic substrates and have better processability.

[0004] Materials for the electrical insulating layer used in metal base substrates include resin compositions in which a heat dissipating filler for improving thermal conductivity is blended with a silicone resin, an epoxy resin, etc. For example, Patent Document 1 proposes a resin composition for circuit boards that contains a vinylsilyl group-containing polysiloxane, a hydrosilyl group-containing polysiloxane, and an inorganic filler. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2018 / 173945 Summary of the Invention [Problem to be solved by the invention]

[0006] Electrical insulating layers for metal base substrates used in electronic devices, particularly in-vehicle electronic devices, are required to have not only excellent electrical insulation and thermal conductivity, but also low elasticity to prevent solder cracks, resistance to solder heat, and good coating properties, such as no uneven flow or bubble formation when applied to a substrate or pressed as a resin composition for the electrical insulating layer before curing.

[0007] In this regard, in the technology described in Patent Document 1, the insulating layer obtained from the resin composition described therein may have a fairly good adhesion to metal substrates and low elasticity, but on the other hand, since it is based on a highly water-repellent silicone resin, there is a risk of uneven coating on the metal substrate, and therefore coatability and, in turn, workability are not taken into consideration.

[0008] On the other hand, if a relatively large rubber-like polymer compound with an Mw of 100,000 or more is used and a high content of heat-dissipating filler is blended into it, bubbles are likely to form during coating and drying of the resulting resin composition, which may in turn cause swelling of the insulating layer or a decrease in the withstand voltage during solder heating.

[0009] In view of the above, the present invention aims to find an electrical insulating layer for a metal base substrate used in electronic components, particularly in automotive electronic components, that has high electrical insulation properties, high thermal conductivity, high solder heat resistance, and low elasticity, and that, as a resin composition for the electrical insulating layer before curing, has good workability when applied to an object to be coated. [Means for solving the problem]

[0010] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by employing a rubbery polymer compound having a glass transition temperature and a weight-average molecular weight within a specific range as a matrix component of a resin composition that can form an electrical insulating material, and have thus completed the present invention.

[0011] That is, the object of the present invention is to (A) a rubbery polymer compound having a glass transition temperature (Tg) of −40° C. or lower and a weight average molecular weight (Mw) in the range of 8,000 to 50,000; (B) epoxy resin, (C) a filler, and (D) Phenoxy resin The above-mentioned problems can be solved by a thermosetting resin composition comprising: A preferred embodiment of the present invention is the above-mentioned thermosetting resin composition, wherein the rubbery polymer compound has an isoprene or butadiene skeleton. In particular, the present invention relates to the above-mentioned thermosetting resin composition, wherein the epoxy resin is preferably in a liquid state at room temperature (25°C). Another aspect of the present invention is a resin-coated metal foil characterized by having, on a metal foil or a carrier-coated metal foil, a resin layer in a B-stage state (semi-cured state) obtained by heating and drying any of the above-mentioned thermosetting resin compositions. Another aspect of the present invention relates to a dry film comprising a carrier film and a resin layer in a B-stage (semi-cured) state obtained by heat-drying any one of the thermosetting resin compositions described above. The resin layer in the B-stage (semi-cured) state described above can be obtained by heat-drying at a temperature of, for example, 80°C for about 30 minutes. Yet another aspect of the present invention relates to a cured product obtained by curing the resin layer of the resin-coated metal foil or the resin layer of the dry film. Yet another aspect of the present invention relates to a metal base substrate having the above-mentioned cured product on a metal substrate. The present invention also relates to a method for producing a metal base substrate, which is obtained by superposing the resin layer side of the resin-coated metal foil on one or both sides of a metal substrate and then heating and pressing it in a vacuum press. Furthermore, the present invention also relates to a method for producing a metal base substrate, characterized in that it is obtained by overlaying a metal foil on a metal substrate having a resin layer in a B-stage state (semi-cured state) obtained by applying any of the above-mentioned thermosetting resin compositions and heating and drying it, and then heating and pressing it in a vacuum press. A further aspect of the present invention relates to a method for producing an electronic component, which comprises using the cured product, the metal base substrate, or the metal base substrate obtained by the method for producing an electronic component. [Effects of the Invention]

[0012] The present invention not only provides an electrical insulator for a metal base substrate used in, for example, electronic components, which has high electrical insulation, high thermal conductivity, high soldering heat resistance, and low elasticity, but also provides a thermosetting resin composition capable of forming an electrical insulator that has good workability when applied to a metal foil. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing a resin-coated metal foil of the present invention, in which the resin layer of this resin-coated metal foil is in a B-stage state (semi-cured state). [Figure 2]1 is a schematic diagram showing one embodiment of a metal base substrate of the present invention. [Figure 3] 1 is a schematic diagram showing a laminate made up of a metal plate (aluminum plate) and a resin layer in a B-stage state (semi-cured state) thereon. [Figure 4] This is a schematic diagram showing the area where the copper foil on the metal base substrate has been removed by etching, leaving two layers: an electrical insulating layer (cured product) and a metal plate (aluminum plate). DETAILED DESCRIPTION OF THE INVENTION

[0014] The thermosetting resin composition of the present invention (hereinafter also referred to as the "resin composition of the present invention") is not only intended to be used as an electrical insulator for electronic components, but is also required to have the ability to efficiently dissipate heat generated in the electronic components. Therefore, the resin composition of the present invention essentially contains a rubbery polymer compound and a filler as its main components. Furthermore, the resin composition may contain an epoxy resin and a phenoxy resin to impart other desirable properties as an electrical insulator or to improve the handleability (workability or coatability) of the resin composition. The components of the resin composition of the present invention will be described below.

[0015] [(A) A rubbery polymer compound having a glass transition temperature (Tg) of −40° C. or lower and a weight average molecular weight (Mw) in the range of 8,000 to 50,000] (hereinafter also referred to as (A) rubbery polymer compound) The rubbery polymer compound (A) contained in the resin composition of the present invention preferably has a glass transition temperature and a weight average molecular weight (Mw) each within a specific range. More specifically, the present invention preferably uses a rubbery polymer compound (A) having a glass transition temperature (Tg) of −40° C. or lower and a weight average molecular weight (Mw) in the range of 8,000 to 50,000.

[0016] If the (A) rubbery polymer compound has a glass transition temperature of -40°C or lower, the cured product obtained from the resin composition containing it will have high thermal conductivity, low elasticity, and increased peel strength. More preferred (A) rubbery polymer compounds have a glass transition temperature of -50°C or lower.

[0017] On the other hand, if the weight-average molecular weight (Mw) of the (A) rubbery polymer compound is in the range of 8,000 to 50,000, the resin composition containing it will have good tackiness after coating and drying, will be less likely to flow during pressing for curing, and will have good defoaming properties during drying. In other words, the resin composition will have good coatability and surface condition, and will be less likely to spill over or flow unevenly after pressing, improving workability. A more preferred (A) rubbery polymer compound has a weight-average molecular weight in the range of 10,000 to 50,000.

[0018] The rubbery polymer compound (A) in the present invention is a liquid polymer having a melt viscosity measured at 38° C. in the range of 0.1 to 10,000 Pa·s. A preferred example is a liquid diene rubber. By including such a rubbery polymer compound (A) in the resin composition of the present invention, the composition can become a rubber composition that exhibits excellent processability and adhesiveness.

[0019] (A) As a raw material for the rubbery polymer compound, a polymer obtained by polymerizing a conjugated diene is preferred. Examples of conjugated dienes include butadiene, isoprene, 2,3-dimethylbutadiene, 2-phenylbutadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, myrcene, and chloroprene. Among these conjugated dienes, butadiene and isoprene are preferred. These conjugated dienes may be used alone or in combination of two or more. Polymerization can be performed using methods known to those skilled in the art, such as emulsion polymerization or solution polymerization.

[0020] The (A) rubbery polymer compound may be a copolymer of the above-mentioned conjugated diene and an aromatic vinyl compound. Examples of aromatic vinyl compounds include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-t-butylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 2,4,6-trimethylstyrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, vinylanthracene, N,N-diethyl-4-aminoethylstyrene, vinylpyridine, 4-methoxystyrene, monochlorostyrene, dichlorostyrene, and divinylbenzene, but are not limited thereto. Among these aromatic vinyl compounds, styrene, α-methylstyrene, and 4-methylstyrene are preferred.

[0021] The rubbery polymer compound (A) used in the present invention is preferably one having an isoprene or butadiene skeleton in its chemical structure, such as a homopolymer of isoprene or butadiene, or a copolymer of isoprene and butadiene.

[0022] As the (A) rubbery polymer compound, commercially available products can be used. Examples of such commercially available products include LIR-410, LIR-390, LBR-307, and LBR-305 (manufactured by Kuraray Co., Ltd.).

[0023] From the viewpoint of improving workability and improving the peel strength of the cured product after curing, the content of such a rubbery polymer compound (A) is preferably 30 to 70 parts by mass, and more preferably 40 to 60 parts by mass, per 100 parts by mass of the solids content of the resin composition of the present invention (excluding inorganic filler such as filler (C)).

[0024] [(B) Epoxy resin] The resin composition of the present invention preferably contains (B) an epoxy resin. (B) Epoxy resin has thermosetting properties, and therefore the solder heat resistance of a metal base substrate having a cured product obtained from a resin composition containing this resin can be improved.

[0025] The epoxy resin (B) used in the present invention is preferably one that is liquid at room temperature (25° C.). When an epoxy resin that is liquid at room temperature is contained in a resin composition, the solder heat resistance of the metal base substrate is improved, and the adhesiveness of the resulting cured product to the metal substrate is also improved, resulting in the advantage of increased peel strength. Examples of such liquid epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins having an aromatic structure, glycidyl amine type epoxy resins having an aromatic structure, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton having an aromatic structure, cyclohexanedimethanol type epoxy resins having an aromatic structure, and epoxy resins having a butadiene structure having an aromatic structure, but are of course not limited to these. These may be used alone or in combination of two or more.

[0026] Commercially available liquid epoxy resins can also be used, including, for example, HP4032, HP4032D, and HP4032SS (naphthalene-type epoxy resins) (manufactured by DIC Corporation), 828US and jER828EL (bisphenol A-type epoxy resins), jER806 and jER807 (bisphenol F-type epoxy resins), jER152 (phenol novolac-type epoxy resins), 630 and 630LSD (glycidylamine-type epoxy resins) (manufactured by Mitsubishi Chemical Corporation), ZX1059 (a mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin), jER871 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), EX-721 (glycidyl ester-type epoxy resin) (manufactured by Nagase ChemteX Corporation), and Celloxide 2021P (alicyclic epoxy resin having an ester skeleton) (manufactured by Daicel Corporation). , ZX1658, ZX1658GS (liquid 1,4-glycidylcyclohexane) (manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0027] From the viewpoint of maintaining the solder heat resistance required for the metal base substrate of the present invention, such (B) epoxy resin is preferably contained in an amount of 20 to 45 parts by mass, and more preferably 25 to 40 parts by mass, per 100 parts by mass of the solid content of the resin composition of the present invention (excluding inorganic fillers such as (C) filler).

[0028] [(C) Filler] The metal base substrate of the present invention must be electrically insulating and thermally conductive for its intended use, and therefore the resin composition of the present invention, which is the material for the substrate, contains a filler (C) capable of exhibiting thermal conductivity.

[0029] Examples of the filler (C) used in the present invention include alumina, aluminum nitride, boron nitride, silicon carbide, and silicon nitride, and among these, alumina is particularly preferred. The thermal conductivity (20°C) of the filler (C) capable of exhibiting thermal conductivity is preferably 10 W / mK or more, and more preferably 20 W / mK or more. In order to improve moisture resistance and dispersibility, the surface may be treated with a surface treatment agent such as a silane coupling agent.

[0030] These fillers (C) capable of exhibiting thermal conductivity may be used alone or in combination of two or more kinds, or two or more kinds of the same material may be used in combination.

[0031] As the filler (C) capable of exhibiting thermal conductivity, commercially available spherical or pseudo-spherical products can be used. The use of spherical aluminum oxide can mitigate the increase in viscosity that occurs when the filler is highly filled. Examples of such commercially available products include, but are not limited to, DAW-03 and ASFP-20 (both manufactured by Denka Co., Ltd.), and AS-40 (manufactured by Showa Denko Co., Ltd.).

[0032] The average particle size (d50) of the (C) filler is preferably 0.01 μm to 50 μm from the viewpoint of the thermal conductivity of the metal base substrate and the adhesion of the cured product to the metal substrate. The average particle size can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, a particle size distribution of the inorganic filler is created on a volume basis using a laser diffraction / scattering particle size distribution analyzer, and the median diameter is used as the average particle size. A preferred measurement sample is one in which the filler (C) is dispersed in water using ultrasonic waves. Examples of laser diffraction / scattering particle size distribution analyzers that can be used include the LA-500 (manufactured by Horiba, Ltd.) and the SALD2200 (manufactured by Shimadzu Corporation).

[0033] The (C) filler capable of exhibiting thermal conductivity is contained in the resin composition of the present invention in an amount such that the metal base substrate of the present invention has a thermal conductivity of 3 W / mK or more, so that the metal base substrate of the present invention can function as an electrical insulating material having thermal conductivity. Specifically, the content thereof is preferably 65 to 85 parts by mass, more preferably 70 to 80 parts by mass, relative to 100 parts by mass of the resin composition of the present invention.

[0034] [(D) Phenoxy resin] In the present invention, the resin composition preferably contains (D) a phenoxy resin in order to improve the toughness of the cured product and the adhesion between the cured product and copper foil or between the cured product and a metal substrate.

[0035] Examples of such (D) phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a bisphenolacetophenone skeleton, a novolac skeleton, a biphenyl skeleton, a fluorene skeleton, a dicyclopentadiene skeleton, a norbornene skeleton, a naphthalene skeleton, an anthracene skeleton, an adamantane skeleton, a terpene skeleton, and a trimethylcyclohexane skeleton. These (D) phenoxy resins may be used alone or in combination of two or more. Among these, the (D) phenoxy resin used in the present invention is preferably one having a softening point of 60 to 90°C, in order to prevent excessive flow during vacuum pressing.

[0036] (D) Phenoxy resin may, of course, be a commercially available product, such as 1256, 4250, YX8100, YX6954, YL7500BH30, YX6954BH30, YX7553, YX7553BH30, YL7769BH30, YL6794, YL7213, YL7290, and YL7482 (manufactured by Mitsubishi Chemical Corporation), and FX280 and FX293 (manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0037] From the viewpoint of improving the toughness of the cured product of the present invention and improving adhesion to a metal substrate or copper foil, it is preferable that such a (D) phenoxy resin be contained in an amount of 1 to 20 parts by mass per 100 parts by mass of the solid content of the resin composition of the present invention (excluding inorganic fillers such as (C) filler).

[0038] [Hardening agent] In addition to the above components (A) to (D), the resin composition of the present invention may also contain a curing agent in order to adjust the curing time of the resin composition and improve its workability. Examples of such curing accelerators used in the present invention include organic phosphine compounds such as TPP, TPP-K, TPP-S, and TPTP-S (manufactured by Hokko Chemical Industry Co., Ltd.); imidazole compounds such as Curesol 2MZ, 2E4MZ, 2PZ, 1B2PZ, Cl1Z, Cl1Z-CN, Cl1Z-CNS, Cl1Z-A, 2MZ-OK, 2MA-OK, and 2PHZ (manufactured by Shikoku Chemical Industry Co., Ltd.); amine adduct compounds such as Novacure (manufactured by Asahi Kasei Corporation) and Fujicure (manufactured by T&K Toka Corporation); amine compounds such as 1,8-diazabicyclo[5,4,0]undecene-7,4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 4-dimethylaminopyridine; and organometallic complexes or organometallic salts of cobalt, copper, zinc, iron, nickel, manganese, tin, etc. Of course, two or more of these curing accelerators may be used in combination.

[0039] Such a curing agent is contained in the resin composition in an amount sufficient to change the curing rate of the resin composition of the present invention, and the content thereof is preferably 0.5 to 2 parts by mass per 100 parts by mass of the solid content of the resin composition of the present invention (excluding inorganic fillers such as (C) filler).

[0040] [solvent] The resin composition of the present invention may also be diluted with a solvent such as an organic solvent, for example, to adjust its viscosity. The organic solvent can be used to adjust the viscosity of the thermosetting resin composition of the present invention or to adjust the viscosity for application to a substrate. Any known organic solvent can be used as the organic solvent.

[0041] Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum-based solvents, etc. More specifically, ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ... Examples of suitable organic solvents include glycol ethers such as ethylene glycol diethyl ether and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, and propylene glycol butyl ether acetate; alcohols such as ethanol, propanol, ethylene glycol, and propylene glycol; aliphatic hydrocarbons such as octane and decane; and petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. These organic solvents may be used alone or as a mixture of two or more. Such a solvent can be appropriately contained in the resin composition of the present invention in an amount that allows the viscosity of the resin composition to be adjusted to a desired level.

[0042] [Wetting and dispersing agent] As described above, the resin composition of the present invention contains the filler (C). Therefore, in order to disperse the filler well in the resin composition, the resin composition preferably contains a wetting and dispersing agent. Commercially available products of such wetting and dispersing agents include, for example, ANTI-TERRA-U, ANTI-TERRA-U100, ANTI-TERRA-204, ANTI-TERRA-205, DISPERBYK-101, DISPERBYK-102, DISPERBYK-103, DISPERBYK-106, DISPERBYK-108, DISPERBYK-109, DISPERBYK-110, DISPERBYK-111, DISPERBYK-112, DISPERBYK-116, DISPERBYK-130, DISPERBYK-140 , DISPERBYK-142, DISPERBYK-145, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163, DISPERBYK-164, DISPERBYK-166, DISPERBYK-167, DISPERBYK-16 8, DISPERBYK-170, DISPERBYK-171, DISPERBYK-174, DISPERBYK-180, DISPERBYK-182, DISPERBYK-183, DISPERBYK-185, DISPERBYK-184, DISPERBYK-2 000, DISPERBYK-2001, DISPERBYK-2009, DISPERBYK-2020, DISPERBYK-2025, DISPERBYK-2050, DISPERBYK-2070, DISPERBYK-2096, DISPERBYK-2150, BYK-P104, BYK-P104S, BYKP105, BYK-9076, BYK-9077, BYK-220S, BYK-1160, BYK-1165, BYK-W903, BYK-W908, BYK-W909, BYK-W940, BYK-W961, BYK-W966 , BYK-W969, BYK-W972, BYK-W974, BYK-W980, BYK-W985, BYK-W995, BYK-W996, BYK-W9010, BYK-W9011, BYK-W9012 (all manufactured by BYK Japan), Disparlon 2150, Disparlon 1210, Disparlon KS-860, Disparlon KS-873N, Disparlon 7004, Disparlon 1830, Disparlon 1860, Disparlon 1850, Disparlon DA-400N, Disparlon PW-36, Disparlon DA-703-50 (all manufactured by BYK Japan),Examples of such esters include: FLORENE G-450, FLORENE G-600, FLORENE G-820, FLORENE G-700, FLORENE DOPA-44, and FLORENE DOPA-17 (manufactured by Kyoeisha Chemical Co., Ltd.).

[0043] The content of such a wetting and dispersing agent in the resin composition of the present invention is 0.1 to 10 parts by mass, preferably 0.1 to 5 parts by mass, per 100 parts by mass of the filler (C).

[0044] [Silane coupling agents] The resin composition of the present invention preferably contains a silane coupling agent to improve the dispersibility of each component during mixing in the production of the composition. The improved dispersibility has the advantage of improving the mechanical properties of the cured product or the adhesion to a metal substrate. The silane coupling agent can also be used in advance to treat the surface of the component (C) filler.

[0045] Examples of such silane coupling agents include, but are not limited to, vinyl-based silane coupling agents, epoxy-based silane coupling agents, styryl-based silane coupling agents, methacrylic-based silane coupling agents, acrylic-based silane coupling agents, amino-based silane coupling agents, isocyanurate-based silane coupling agents, ureido-based silane coupling agents, mercapto-based silane coupling agents, isocyanate-based silane coupling agents, and acid anhydride-based silane coupling agents.

[0046] As the silane coupling agent, commercially available products can also be used. Examples of such commercially available products include KBM-1003, KBE-1003, KBM-303, KBM-402, KBM-403, KBE-402, KBE-403, KBM-1403, KBM-502, KBM-503, KBE-502, KBE-503, KBM-5103, KBM-602, KBM-603, KBM-903, KBE-903, KBE-9103P, KBM-573, KBM-575, KBM-9659, KBE-585A, KBM-802, KBM-803, KBE-9007N, and X-12-967C (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0047] The content of such a silane coupling agent in the resin composition of the present invention can be appropriately set depending on the desired degree of dispersion, and the content is preferably 0.5 to 2 parts by mass relative to 100 parts by mass of the resin composition of the present invention.

[0048] [Other additives] In addition to the above components, the resin composition of the present invention may contain an antioxidant, an antifoaming agent, a leveling agent, and the like. The antioxidant inhibits oxidation of the conductor (copper) on the substrate, thereby improving adhesion between the substrate and the cured coating of the thermosetting resin composition of the present invention. Examples of antioxidants include hindered phenol compounds such as 3-(N-salicyloyl)amino-1,2,4-triazole, sulfur-based antioxidants such as zinc salts of 2-mercaptobenzimidazole, phosphorus-based antioxidants such as triphenyl phosphite, aromatic amine-based antioxidants such as di-tert-butyldiphenylamine, and heterocyclic compounds containing nitrogen as a heteroatom such as melamine, benzotriazole, and tolyltriazole. Among these, melamine and benzotriazole are preferred, with melamine being particularly preferred.

[0049] When an antioxidant is contained, the content thereof is 0.03 mass % or more and 5 mass % or less, and preferably 0.1 mass % or more and 2 mass % or less, based on the solid content of the resin composition of the present invention (excluding inorganic fillers such as (C) filler).

[0050] On the other hand, antifoaming agents and leveling agents can be added to prevent deterioration of surface smoothness and deterioration of interlayer insulation due to voids and pinholes. Examples of the defoaming agent (leveling agent) include silicone-based defoaming agents and non-silicone-based defoaming agents that are foam-breaking polymer solutions. Commercially available silicone-based defoaming agents include BYK (registered trademark)-063, BYK-065, BYK-066N, BYK-067A, and BYK-077 (all manufactured by BYK Japan), and KS-66 (manufactured by Shin-Etsu Chemical Co., Ltd.). Commercially available non-silicone antifoaming agents include BYK-054, BYK-055, BYK-057, BYK-1790, and BYK-1791 (all manufactured by BYK Japan).

[0051] When an antifoaming agent (leveling agent) is contained, its content is 10 mass % or less, and preferably 0.01 mass % or more and 3 mass % or less, based on the solid content of the resinous composition of the present invention (excluding inorganic fillers such as (C) filler).

[0052] [Metal foil with resin] The resin-coated metal foil of the present invention has a resin layer in a B-stage state (semi-cured state) obtained by applying the resin composition of the present invention to the surface of a metal foil or a metal foil with a carrier, and then drying by heating for about 30 minutes at a temperature of 80° C. For example, the resin-coated metal foil 1 shown in FIG. 1 has a resin layer as an electrical insulating layer 3 (in a B-stage state (semi-cured state)) on copper foil 2 as the metal foil.

[0053] [Metal foil with carrier] The metal foil with a carrier may be formed by laminating a resin layer obtained from the resin composition of the present invention so as to be in contact with the metal foil, and an ultrathin copper foil is preferably used as the metal foil. Examples of the carrier foil include copper foil, aluminum foil, stainless steel (SUS) foil, and resin film with a metal coating on the surface, with copper foil being preferred. The copper foil may be electrolytic copper foil or rolled copper foil. The thickness of the carrier foil is usually 250 μm or less, preferably 9 to 200 μm. A release layer may be formed between the carrier foil and the metal foil, if necessary.

[0054] The method for forming the copper foil is not particularly limited, but an ultrathin copper foil is preferable, and it can be formed by wet film formation methods such as electroless copper plating and electrolytic copper plating, dry film formation methods such as sputtering and chemical vapor deposition, or a combination of these. The thickness of the ultrathin copper foil is preferably 0.1 to 7.0 μm, more preferably 0.5 to 5.0 μm, and even more preferably 1.0 to 3.0 μm.

[0055] [B-stage (semi-cured) resin layer] The resin layer in a B-stage state (semi-cured state) of the present invention can be obtained by heating and drying the resin composition of the present invention for about 30 minutes at a temperature of, for example, 80° C. The resin layer in a B-stage state (semi-cured state) is not usually produced by itself, but can be produced as a resin-coated metal foil by, for example, applying it to a metal foil with a carrier and drying it by heating at a temperature of 80° C. for about 30 minutes. Alternatively, a PET film may be used as a carrier film, and the thermosetting resin composition may be applied onto the carrier film using an applicator, followed by heating and drying at a temperature of 80°C for approximately 30 minutes, thereby producing a dry film in which a resin layer in a B-stage state (semi-cured state) is formed on the carrier film.

[0056] [Metal base board] The metal base substrate of the present invention can be produced, for example, by superposing the resin layer side of the resin-coated metal foil (copper foil) of the present invention on a metal substrate such as aluminum, and curing it by heating and pressurizing it in a vacuum press, for example, at 190°C and 10 MPa for 60 minutes, to produce a metal base substrate 5 consisting of three layers: copper foil 2', electrical insulating layer 3' (cured product), and metal plate (aluminum plate) 4 (Figure 2).This is preferable because it allows the filler (C) in the resin layer to be closest packed. Another method for producing the metal base substrate of the present invention is to apply the resin composition of the present invention to a metal plate (aluminum plate) 4', heat and dry it, and form a B-stage (semi-cured) resin layer (electrical insulating layer 3" (B-stage (semi-cured))) (Figure 3), and then apply a metal foil to this resin layer in a vacuum press, for example, by heating and pressurizing it at 190°C and 10 MPa for 60 minutes to harden and mold it. FIG. 4 shows the area where the copper foil of the metal base substrate has been removed by etching, leaving two layers: an electrical insulating layer 3''' (cured product) and a metal plate (aluminum plate) 4''. The thickness of the cured product itself is preferably thin from the viewpoint of thermal conductivity, but is preferably 75 μm to 200 μm in consideration of voltage resistance.

[0057] The metal substrate may be, for example, copper foil or aluminum foil, with copper foil being more preferred. The copper foil may be a single metal such as copper or an alloy foil with other metals such as tin, chromium, silver, magnesium, nickel, zirconium, silicon, or titanium. The thickness of the metal substrate is generally in the range of 0.1 mm to 5 mm, and preferably in the range of 0.5 mm to 3 mm.

[0058] [Metal base board] (double-sided board) A metal core substrate can be produced by overlapping the resin layer surfaces of the resin-coated metal foil (copper foil) of the present invention on both sides of a metal plate and curing it by heating and pressurizing it in a vacuum press, for example, at 190°C and 10 MPa for 60 minutes. Another method for producing the metal core substrate of the present invention is to apply the resin composition of the present invention to both sides of a metal substrate, heat and dry it to form a resin layer (electrical insulating layer) in a B-stage state (semi-cured state), and then heat and pressurize a metal foil onto the electrical insulating layer in a vacuum press at 190°C, 10 MPa, and for 60 minutes to harden and mold it.

[0059] [Electronic Components] The cured product, laminate, and metal base substrate of the present invention can be suitably used, for example, as a thermally conductive electrical insulator for electronic components of electrical appliances (PCs, smartphones, TVs, radios, etc.) and vehicles (automobiles, trains, ships, aircraft, etc.), such as semiconductor devices and power devices.

[0060] Hereinafter, one embodiment of the present invention will be specifically illustrated by way of an example, but it goes without saying that the purpose is not to limit the scope of the invention according to the claims of this application. Unless otherwise specified, the "parts" and "%" shown are based on mass. [Example]

[0061] [Production of Resin Compositions of Examples 1 to 5 and Comparative Examples 1 to 4] The resin compositions of Examples 1 to 5 and Comparative Examples 1 to 4 were each produced by blending and adding the materials according to the compositions and ratios shown in Table 1 below, and stirring and degassing the mixture for 5 minutes using a centrifugal degassing mixer.

[0062] [Table 1] *1 LIR-410 (Kuraray Co., Ltd.; Mw: 30,000; Tg: -59°C; Melt viscosity (38°C): 430 Pa·s) *2 LIR-390 (Kuraray Co., Ltd.; Mw: 48,000; Tg: -95°C; Melt viscosity (38°C): 400 Pa·s) *3 LBR-307 (Kuraray Co., Ltd.; Mw: 10,000; Tg: -95°C; Melt viscosity (38°C): 1.5 Pa·s) *4 LBR-305 (Kuraray Co., Ltd.; Mw: 26,000; Tg: -95°C; Melt viscosity (38°C): 40 Pa·s) *5 LIR-50 (Kuraray Co., Ltd.; Mw: 54,000; Tg: -63°C; Melt viscosity (38°C): 500 Pa s) *6 Nipol AR-53L (manufactured by Nippon Zeon Co., Ltd.; Mw: 1,500,000; Tg: -32°C) *7 LBR-302 (Kuraray Co., Ltd.; Mw: 5,500; Tg: -85°C; Melt viscosity (38°C): 0.6 Pa·s) *8 UF-3003M (Kyoeisha Chemical; Mw: 20,000; Tg: -33°C) *9 jER871 (Mitsubishi Chemical Corporation) *10 ZX1059 (manufactured by Nippon Steel Chemical & Material Co., Ltd.; a mixture of bisphenol A and bisphenol F) *11 BYK-W9010 (BYK, copolymer with acidic groups) *12 KBM-403 (Shin-Etsu Chemical Co., Ltd.) *13 4250 (Mitsubishi Chemical Corporation; Mixture of bisphenol A and bisphenol F; Mw: 60,000) *14 Curezol 1B2PZ (Shikoku Chemicals Co., Ltd.; 1-benzyl-2-phenylimidazole) *15 ANON (Ube Industries; cyclohexanone) *16 AS-30 (Showa Denko; alumina powder; d50: 18 μm) *17 DAW-03 (Denka; alumina powder; d50: 4 μm) *18 ASFP-20 (Denka; alumina powder; d50: 0.3 μm)

[0063] [Melt viscosity measurement method] (A) The melt viscosity of the rubbery polymer compound at 38°C was measured using a Brookfield viscometer (manufactured by Brookfield Engineering Labs. Inc.).

[0064] [Method for measuring glass transition temperature (Tg)] (A) 10 mg of a rubbery polymer compound was placed in an aluminum pan, and a thermogram was measured by differential scanning calorimetry (DSC) at a heating rate of 10°C / min. The top value was taken as the glass transition temperature.

[0065] [Preparation of the substrate] The resin compositions of Examples 1 to 5 and Comparative Examples 1 to 4 were applied to one side of a 35 μm-thick copper foil using a bar coater, and heated at 80°C for 30 minutes in a hot air circulation drying oven to dry the solvent and produce a 100 μm-thick B-stage (semi-cured) resin layer. Next, the B-stage (semi-cured) resin layer previously formed on the copper foil was superimposed on a 1.0 mm aluminum substrate, and cured by heating and pressing in a vacuum press at 190°C, 10 MPa, and 60 minutes to produce a metal-based laminate consisting of three layers: aluminum substrate, electrical insulation layer, and copper foil.

[0066] [Test Example 1] Coating properties and surface condition The resin compositions of Examples 1 to 5 and Comparative Examples 1 to 4 were diluted and applied to copper foil using a bar coater to a dry thickness of 100 μm. The coating was then heated at 80°C for 30 minutes in a hot air circulation box-type drying oven, and the appearance of the coating surface of the resin layer in a B-stage state (semi-cured state) after drying was visually observed. The evaluation criteria were as follows: Evaluation criteria: ◎: No bubbles or repellency, uniform and flawless appearance 〇: No bubbles or repellency, but there are protrusions or dents on the coating ×: Bubbles and popping The results are shown in Table 2 below.

[0067] [Test Example 2] Extrusion after pressing Test substrates for Examples 1 to 5 and Comparative Examples 1 to 4 were prepared in the same manner as in the above [Preparation of Substrate]. The degree of fluidity of the resin composition from the edges of the copper foil and aluminum plate was visually evaluated. The evaluation criteria were as follows: Evaluation criteria: 〇: No or very little overflow, allowing for uniform molding ×: There is a lot of overflow and the film on the press edge is thin The results are shown in Table 2 below.

[0068] [Test Example 3] Uneven flow after pressing Test substrates for Examples 1 to 5 and Comparative Examples 1 to 4 were prepared in the same manner as in the above [Preparation of Substrate]. Then, the copper foil was peeled off, and the remaining resin layer was visually evaluated for unevenness. The evaluation criteria were as follows: Evaluation criteria: 〇: Uniform molding was achieved ×: There were unevenness in film thickness, color, wrinkles, etc. depending on the location. The results are shown in Table 2 below.

[0069] [Test Example 4] Solder heat resistance Test substrates (50 x 50 mm) for Examples 1 to 5 and Comparative Examples 1 to 4 were prepared using the same method as in [Preparation of Substrates] above. Then, the test substrates were floated with the aluminum substrate facing downwards in a solder bath at 260°C for 30 minutes. After that, each test substrate was visually evaluated for the presence or absence of blistering or peeling. The evaluation criteria were as follows: Evaluation criteria: ◯: No swelling or peeling ×: Blisters and peeling The results are shown in Table 2 below.

[0070] [Test Example 5] Voltage resistance The copper foil of the test substrates of Examples 1 to 5 and Comparative Examples 1 to 4 was etched to form copper foil lands with a diameter of 20 mm, thereby producing samples. The withstand voltage was measured using a Kikusui Electronics TOS5051A withstand voltage tester. The withstand voltage measurement started at 1 kV AC and was increased at a rate of 25 V / sec, and the lowest voltage at which the sample experienced dielectric breakdown was recorded as the withstand voltage. The evaluation criteria were as follows: Rating criteria: 4 or above: ◎ 3 or more: Yes Less than 3: × Unmeasurable:- The results are shown in Table 2 below.

[0071] [Test Example 6] Peel strength The copper foil of the test substrates of Examples 1 to 5 and Comparative Examples 1 to 4, which had been cut to the specified dimensions, was partially removed by etching to form a 10 mm wide copper foil pattern. One end of this copper foil pattern was then peeled off, and the copper foil pattern was peeled off at a rate of 50 mm / min while applying a force perpendicular to the surface of the electrical insulating layer of the test substrate. The force applied to the copper foil pattern at this time was taken as the T-peel strength and was measured using an autograph AG-X manufactured by Shimadzu Corporation. The evaluation criteria were as follows: Rating criteria: Over 10: ◎ 5 or more and 10 or less:〇 Less than 5: × Unmeasurable:- The results are shown in Table 2 below.

[0072] [Test Example 7] Glass transition temperature (Tg) (DMA) Using a bar coater, the resin compositions of Examples 1 to 5 and Comparative Examples 1 to 4 were applied to copper foil and heated and dried at 80°C for 30 minutes in a hot air circulation drying oven to create a B-stage (semi-cured) resin layer. Then, copper foil was placed on top of the coated resin and the resulting resin was heat-cured for 60 minutes at 190°C and 10 MPa in a vacuum press. The coated resin was then immersed in MEC soft etching agent CB801 heated to 30°C for 30 minutes to etch away the copper foil, producing a single-layer electrical insulating layer. The glass transition temperature (Tg) of each of these single-layer insulating layers was measured using a Solids Analyzer RSA-G2 manufactured by Tin Instruments. The results are shown in Table 2 below (unit: °C).

[0073] [Test Example 8.] Storage modulus (E'@25) Single films of the electrical insulating layer of Examples 1 to 5 and Comparative Examples 1 to 4 were prepared in the same manner as in Test Example 7 above, and the storage modulus of each single film was measured at 25°C at a frequency of 1 Hz using a Solids Analyzer RSA-G2 manufactured by Tainstrum. The evaluation criteria were as follows: Evaluation criteria: 1GPa or less: ◎ More than 1GPa and less than 2GPa:〇 Over 2GPa: × Unmeasurable :- The results are shown in Table 2 below.

[0074] [Test Example 9] Thermal conductivity The resin compositions of Examples 1 to 5 and Comparative Examples 1 to 4 were applied to one side of a 35 μm-thick copper foil using a bar coater, and then heated at 80°C for 30 minutes in a hot air circulation drying oven to evaporate the solvent, producing 100 μm-thick electrical insulating layers, which were resin layers in a B-stage state (semi-cured state). Copper foil was then placed on top of the electrical insulating layers formed on the copper foil, and the layers were cured by heating and pressing at 190°C and 10 MPa for 60 minutes in a vacuum press. The copper foil was then peeled off to obtain a film-like cured product. The thermal conductivity of these film-like cured products was then measured using a QTM500 manufactured by Kyoto Electronics Manufacturing Co., Ltd. The thermal conductivity (W / mK) was calculated as the average value of n=3. Although not shown in Table 2, the results were 3 W / mK or higher for all of the film-like cured products of Examples 1 to 5 and Comparative Examples 2 and 4. For Comparative Examples 1 and 3, sheet molding was not possible, so measurement was not possible.

[0075] [Table 2] [Explanation of symbols]

[0076] 1. Resin-coated metal foil 2,2' copper foil 3,3',3",3"' Electrical insulation layer 4,4',4" Metal plate (aluminum plate) 5 Metal base board

Claims

1. A thermosetting resin composition, comprising: (A) a rubbery polymer compound having a glass transition temperature (Tg) of −40° C. or lower and a weight average molecular weight (Mw) in the range of 8,000 to 50,000; (B) an epoxy resin; (C) a filler, and (D) Phenoxy resin Contains the content of the (A) rubbery polymer compound having a glass transition temperature (Tg) of −40° C. or lower and a weight average molecular weight (Mw) in the range of 8,000 to 50,000 is 30 to 70 parts by mass per 100 parts by mass of the solid content of the thermosetting resin composition (excluding the (C) inorganic filler such as the filler); the content of the (B) epoxy resin is 25 to 45 parts by mass relative to 100 parts by mass of the solid content of the thermosetting resin composition (excluding the (C) inorganic filler, etc.); The content of the filler (C) is 65 to 85 parts by mass relative to 100 parts by mass of the thermosetting resin composition, and The content of the (D) phenoxy resin is 1 to 20 parts by mass relative to 100 parts by mass of the solid content of the thermosetting resin composition (excluding the (C) inorganic filler). A thermosetting resin composition comprising:

2. 2. The thermosetting resin composition according to claim 1, wherein the rubber-like polymer compound has an isoprene or butadiene skeleton.

3. 3. The thermosetting resin composition according to claim 1, wherein the epoxy resin is liquid at room temperature (25°C).

4. A resin-coated metal foil characterized by having a resin layer in a B-stage state (semi-cured state) obtained by heating and drying the thermosetting resin composition according to any one of claims 1 to 3 on a metal foil or a metal foil with a carrier.

5. A dry film characterized by having, on a carrier film, a resin layer in a B-stage state (semi-cured state) obtained by heating and drying the thermosetting resin composition according to any one of claims 1 to 3.

6. A cured product obtained by curing the resin layer of the resin-coated metal foil according to claim 4 or the resin layer of the dry film according to claim 5.

7. A metal base substrate having the cured product according to claim 6 on a metal substrate.

8. 5. A method for producing a metal base substrate, comprising superposing the resin layer side of the resin-coated metal foil according to claim 4 on one or both sides of a metal substrate, and heating and pressing the same in a vacuum press.

9. A method for producing a metal base substrate, characterized in that it is obtained by applying a thermosetting resin composition according to any one of claims 1 to 3, heating and drying the resin layer in a B-stage state (semi-cured state), and then superposing a metal foil on the metal substrate, and then heating and pressing the metal foil in a vacuum press.

10. A method for producing an electronic component, comprising using the cured product according to claim 6, the metal base substrate according to claim 7, or the metal base substrate obtained by the production method according to claims 8 or 9.

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