Abstract: The present invention relates to a novel latent curing agent which is capable of controlling the initiation reaction stage and is curable by heat and/or UV-light, an epoxy resin composition containing it, and a mixed epoxy composition (blend) having different functional groups. Particularly, it has been found that the epoxy resin composition consisting of an aliphatic type epoxy (CAE) and/or a difunctional bisphenol A type epoxy (DGEBA) has excellent mechanical properties.

Abstract: An inter-laminar adhesive composition containing: (A) a liquid epoxy resin; (B) a polyfunctional epoxy resin having a softening point higher than a lamination temperature of the adhesive and with two or more epoxy groups within the molecule; and (C) a latent epoxy curing agent initiating a reaction at a temperature higher than the lamination temperature; wherein the adhesive composition optionally contains a liquid resin other than component (A) and/or an organic solvent and wherein the liquid resin including component (A), the organic solvent or both constitute from 10 to 55% by weight of the composition, and the use of this interlaminar adhesive composition to prepare a multilayer printed wiring board, and the process for preparing the multilayer printed wiring board are provided.

Abstract: A process for making an improved current limiting composition comprising mixing an epoxy thermosetting resin containing more than one 1,2 epoxy groups per molecule with an acid anhydride curing agent, an epoxy reactive diluent, first and second co-accelerators and conductive additive particles to form a liquid mixture. The liquid mixture is heated at a first temperature range below gelation temperature while drawing a vacuum to drive off volatiles and gases. Continued heating at a second temperature range promotes gelation and heating a third temperature range effects a final cure. A first co-accelerator becomes effective during the gelation temperature range and a second co-accelerator does not become effective until the final cure temperature range. Gelation takes about 2 to 4 hours at about 130° C. to 140° C. and final cure takes about 13 to 18 hours at about 140° C. to 160° C.

Abstract: A method of making a thermally-removable epoxy by mixing a bis(maleimide) compound to a monomeric furan compound containing an oxirane group to form a di-epoxy mixture and then adding a curing agent at temperatures from approximately room temperature to less than approximately 90° C. to form a thermally-removable epoxy. The thermally-removable epoxy can be easily removed within approximately an hour by heating to temperatures greater than approximately 90° C. in a polar solvent. The epoxy material can be used in protecting electronic components that may require subsequent removal of the solid material for component repair, modification or quality control.

Abstract: In a liquid epoxy resin composition comprising a liquid epoxy resin and an inorganic filler, a specific imidazole compound having a solubility of up to 1% by weight in the epoxy resin, a melting point of at least 170° C., a mean particle diameter of 1-5 &mgr;m, and a maximum particle diameter of up to 20 &mgr;m is used as a curing accelerator. The resulting composition is suited as a sealing material for flip-chip type semiconductor devices since it has improved thin-film infiltration and storage stability.

Abstract: A lubricating coating compound used for forming a thermosetting synthetic resin lubricating film, wherein a resin composition composed of an epoxy resin, a curing agent, a reactive silicone oil with an epoxy group, and a triazinethiol is dissolved in an organic solvent, wherein if the sum of the epoxy resin and the curing agent is set to 100 parts by weight, the sum of the reactive silicone oil with an epoxy group and the triazinethiol is 2 to 30 parts by weight.

Abstract: A composition is useful as a prepreg containing reinforcing fibers comprises an epoxy resin, a thermoplastic elastomer of a polyamide and/or polyester block copolymer, a curing agent such as dicyandiamide, and optionally a thermoplastic resin such as a polyvinyl formal resin.

Abstract: Unsaturated hydrophobic resins modified with labile hydrophillic groups exhibit reversible solubility in water. Beta-dialkyl amino carboxylate derivatives of novolak resins are useful to make baking enamels and resists.

Abstract: Curable epoxy resin composition comprising a bisphenol based epoxy resin having between 1.1 and 2.5 epoxy groups on average per molecule, a polyhydric phenol curing agent having more than two phenolic hydroxyl groups on average per molecule and red phosphorus. Also are described a process for the production of such curable epoxy resin compositions, the use of the compositions, especially in the impregnation of fibrous fibers, and products comprising or coated by the partly cured or cured epoxy resin compositions, especially impregnated fibrous fibers and laminates made therefrom.

Abstract: This invention relates to adhesive formulations, which can be snap-cured without loss of adhesive strength (as measured by die shear strength) and flexibility (as measured by radius of curvature), comprising 20-80 parts by weight of a flexible epoxy resin comprising an oligomeric backbone of alkylene or alkyleneoxy repeat units, terminated with an aromatic moiety bearing one or more epoxy functionalities, and 80-20 parts by weight of an aromatic O-glycidyl ether (to a total 100 parts), a curing catalyst, and optionally one or more fillers, and a phenolic hardener.

Abstract: This invention relates to adhesive formulations, which can be snap-cured without loss of adhesive strength (as measured by die shear strength) and flexibility (as measured by radius of curvature), comprising 20-80 parts by weight of a flexible epoxy resin and 80-20 parts by weight of an aromatic O-glycidyl ether (to a total 100 parts), a curing catalyst, and optionally one or more fillers.

Abstract: This invention relates to adhesive formulations, which can be snap-cured without loss of adhesive strength (as measured by die shear strength) and flexibility (as measured by radius of curvature), comprising 20-80 parts by weight of a flexible epoxy resin and 80-20 parts by weight of an aromatic O-glycidyl ether (to a total 100 parts), a curing catalyst, and optionally one or more fillers.

Abstract: Epoxy resin mixtures for the production of prepregs and composites contain the following components:a phosphorus-modified epoxy resin with an epoxy value of 0.02 to 1 mol/100 g, made up of structural units derived from(a) polyepoxy compounds with at least two epoxy groups per molecule, and(b) phosphinic acid anhydrides, phosphonic acid anhydrides, or phosphonic acid half-esters;an amine-substituted aromatic sulfonic acid amide or hydrazide as a hardener;an amino hardening accelerator.

Abstract: A curable resin system in supercritical carbon dioxide as diluent includes an epoxy resin, a co-reactant selected from poly N-substituted aziridines, and a catalyst to promote cure at ambient temperature. The system is compatible with various epoxy resins such as bisphenol A epoxy, bisphenol F epoxy, novolac epoxy, cycloaliphatic epoxy, triglycidyl-aminophenol, and triglycidyl isocyanurate. The aziridine co-reactant may be selected from reaction products of NH aziridines with acrylates and methacrylates of trimethylolpropane, ethylene glycol, propylene glycol, bisphenol A, bisphenol F, pentaerythritol, glycerol, and their alkoxylated derivatives; reaction products of NH aziridines with epoxy compounds; and 1-aziridine ethanol and its reaction products with epoxy and isocyanate functional compounds. Suitable catalysts include acid salts and complexes, strong electron accepting compounds, combinations of silicon hydrides and metal complexes, and non-halogen containing boron derivatives.

Abstract: A method and encapsulation material are provided for processing an electronic circuit assembly having surface mount integrated circuit packages mounted with soldered leads to its substrate, in which encapsulation of the soldered lead joints serves to enhance the fatigue life of the solder joints. The encapsulation material is a reactive hot melt epoxy that is curable at temperatures significantly lower than that required for previous epoxy-based encapsulation materials. As such, processing of the circuit assembly is greatly facilitated, while the benefit of encapsulated solder joints is achieved for the assembly. The encapsulation material further includes a latent curative and a filler material for lower the coefficient of thermal expansion of the encapsulation material.

Abstract: Epoxy resin mixtures for producing prepregs and composites that are available at low cost and can be processed well yield flame-retardant molding materials even without the addition of flame retardants, and these molding materials have a high glass transition temperature and also have an improved interlaminar adhesion and adhesion to copper when they contain the following components:a phosphorus-modified epoxy resin with an epoxy value of 0.02 to 1 mol/100 g, composed of structural units derived from(A) polyepoxy compounds with at least two epoxy groups per molecule and(B) at least one compound from the group consisting of phosphinic acids, phosphonic acids, pyrophosphonic acids and phosphonic acid half-esters, andan aromatic polyamine as the hardener.

Abstract: Aqueous primer compositions containing substantially no volatile organic solvents, suitable for promoting the bonding of a metal adherend to a second adherend, are prepared by dispersing one or more solid epoxy resins and a solid curing agent into water such that the particle sizes of the solids are less than 30 .mu.m. The primer compositions are environmentally superior to solvent based primers without loss of physical properties, are storage stable, and exhibit excellent solvent resistance.

Abstract: A coating composition containing a resin composition consisting of (A) 10 to 90 parts by weight of at least one resin selected from polyester resin having a glass transition temperature of -5.degree. C. to 80.degree. C. and a number average molecular weight of 5,000 to 30,000, and epoxy-modified polyester resin having a glass transition temperature of 10.degree. C. to 130.degree.0 C. and a number average molecular weight of 6,000 to 30,000; (B) 5 to 70 parts by weight of novolac-based epoxy resin and (C) 5 to 40 parts by weight of a curing agent per 100 parts by weight of the resin composition respectively; and (D) 20 to 120 parts by weight of an anticorrosion pigment per 100 parts by weight of the resin composition.

Abstract: Epoxy resin mixtures for producing prepregs and composites that are available at low cost and can be processed well yield flame-retardant molding materials even without the addition of flame retardants, and these molding materials have a high glass transition temperature and also have an improved interlaminar adhesion and adhesion to copper when they contain the following components:a phosphorus-modified epoxy resin with an epoxy value of 0.02 to 1 mol/100 g, composed of structural units derived from(A) polyepoxy compounds with at least two epoxy groups per molecule and(B) phosphinic acid anhydrides and/or phosphonic acid anhydrides, andan aromatic polyamine as the hardener.

Abstract: The improved coating of the present invention provides a protective coating for pipe, tubular shapes, other metal members, and metal structures. The protective coating comprises a polymer concrete, which is preferably a mixture of an organic resin, a filler material and a chemical activator. The organic resin is preferably a mixture of thermosetting polymer resins, such as bisphenol A based epoxy, bisphenol A based epoxy blended with polyglycol di-epoxide, and polyglycol di-epoxide. The filler material may be calcium carbonate, silica flour, zeosphere, talc, or kaolin, and preferably is of up to 200 mesh in size. The chemical activator preferably is an amine, such as aminoethylpiperazine or tetraethylene pentamine.

Abstract: The improved coating of the present invention provides a protective coating for pipe, tubular shapes, other metal members, and metal structures. The protective coating comprises a polymer concrete, which is preferably a mixture of an organic resin, a filler material and a chemical activator. The organic resin is preferably a mixture of thermosetting polymer resins, such as bisphenol A based epoxy, bisphenol A based epoxy blended with polyglycol di-epoxide, and polyglycol di-epoxide. The filler material may be calcium carbonate, silica flour, zeosphere, talc, or kaolin, and preferably is of up to 200 mesh in size. The chemical activator preferably is an amine, such as aminoethylpiperazine or tetraethylene pentamine.

Abstract: The improved coating of the present invention provides a protective coating for pipe, tubular shapes, other metal members, and metal structures. The protective coating comprises a polymer concrete, which is preferably a mixture of an organic resin, a filler material and a chemical activator. The organic resin is preferably a mixture of thermosetting polymer resins, such as bisphenol A based epoxy, bisphenol A based epoxy blended with polyglycol di-epoxide, and polyglycol di-epoxide. The filler material may be calcium carbonate, silica flour, zeosphere, talc, or kaolin, and preferably is of up to 200 mesh in size. The chemical activator preferably is an amine, such as aminoethylpiperazine or tetraethylene pentamine.

Abstract: The invention relates to a novel electrocoating composition for metallic substrates that exhibits "thick-build" protective properties at "medium-build" thicknesses. It is composed of a self-addition epoxy resin-polyamine adduct, a blocked isocyanate cross-linker, a polyglycol-polyamine grind resin, a plasticizer, an anti-cratering agent and pigments.

Abstract: The invention relates to a novel electrocoating composition for metallic substrates that exhibits "thick-build" protective properties at "medium-build" thicknesses. It is composed of a self-addition epoxy resin-polyamine adduct, a blocked isocyanate cross-linker, a polyglycol-polyamine grind resin, a plasticizer, an anti-cratering agent and pigments.

Abstract: Polymeric systems are disclosed that exhibit the Johnsen-Rahbeck effect and an electrostatic clutch for using films of these polymeric systems. The films may be pressed from the polymeric reaction product of either a polymer having an anionic functionality reacted with cations, or a polymer having cationic functionality reacted with anions. The dielectric film may be interposed between nesting, or otherwise contacting, conductive surfaces to increase the frictional force between the surfaces by the Johnsen-Rahbeck effect when a voltage differential is applied across the surfaces.

Abstract: A curing agent for epoxy resins is prepared from an amine and an epoxy, as well as subsequent modification by a polyisocyanate compound, in such a manner that the curing agent is in the form of small spherical particles. The particles can be as small as 0.1 microns. This curing agent can be easily dispersed in curing agent masterbatches and curable compositions with minimal effect on their storage stability. The resulting curable compositions have a wide range of applications, including automobile and electronic adhesives.

Abstract: The improved coating of the present invention provides a protective coating for pipe, tubular shapes, other metal members, and metal structures. The protective coating comprises a polymer concrete, which is preferably a mixture of an organic resin, a filler material and a chemical activator. The organic resin is preferably a mixture of thermosetting polymer resins, such as bisphenol A based epoxy, bisphenol A based epoxy blended with polyglycol di-epoxide, and polyglycol di-epoxide. The filler material may be calcium carbonate, silica flour, zeosphere, talc, or kaolin, and preferably is of up to 200 mesh in size. The chemical activator preferably is an amine, such as aminoethylpiperazine or tetraethylene pentamine.

Abstract: An epoxy resin composition contains an epoxy resin represented by the formula (I) and a curing accelerator: ##STR1## wherein R.sup.1 stands for ##STR2## where G stands for a glycidyl group, R.sup.2 stands for an alkyl group having 1 to 4 carbon atoms, R.sup.3 and R.sup.4 stand for the same or different groups and each denote a hydrogen atom or a glycidyl group, m and x each denote an integer of 0 to 10, n denotes an integer of 0 to 2, provided that m.gtoreq.x and, if m=0, then x=0, in which case at least one of R.sup.3 and R.sup.4 denotes a glycidyl group on the condition that when m.gtoreq.1 and m>x, R.sup.1 may each stand for different groups.

Abstract: An essentially water-free solvent system comprising methoxy acetone and an organic protic solvent is useful as a solvent fora) a curing agent for an epoxy resin and/orb) a curing catalyst and/orc) a cure inhibitor.

Abstract: The invention provides epoxy resin compounds for manufacturing prepregs and composite materials, which can be obtained inexpensively and have good processibility, and provide--without having to add flameproofing agents--virtually inflammable molded materials with a high glass transition temperature. The epoxy resin compounds contain the following constituents:(A) an aromatic and/or heterocyclic polyepoxide resin that is free of phosphorous, optionally in a mixture with an aliphatic epoxy resin;(B) an epoxy-group-containing phosphorous compound and(C) an aromatic polyamine as a curing agent.

Abstract: A coating composition useful for a finish for automobiles and trucks in which the film forming binder comprises an acrylic polymer having at least two reactive acid groups, an epoxy-containing crosslinker, a melamine resin, and an epoxy-silane modifying agent. The composition may be used as a one-package system with a reasonable pot life. The composition is characterized by improved environmental resistance.

Abstract: The invention provides epoxide resin molding compositions for protectively covering semiconductor components, which are accessible in a cost-effective manner and have good processibility. The epoxide resin molding compositions provide virtually inflammable molded materials with a high glass transition temperature and a low thermal expansion coefficient without the addition of flameproofing agents, when they contain the following constituents:(A) an aromatic and/or heterocyclic polyepoxide resin which is free of phosphorous, optionally in combination with an aliphatic epoxide resin;(B) an epoxide-group-containing phosphorous compound;(c) an aromatic polyamine as a curing agent; and(D) filler material.

Abstract: Epoxy resin compositions having improved storage stability before curing and improved thermal and mechanical performance after curing comprise a mixture of a polyepoxide and a curing agent that is reactive with the polyepoxide. The epoxy resin composition is characterized by a glass transition temperature of less than 20.degree. C., measured under standard conditions, after subjecting the epoxy resin composition to a specified thermal cycle. The preferred curing agents are aromatic diamines, for example, 3,7-diaminodibenzothiophene-5,5-dioxide; 3,7-diaminophenothiazine sulfone, 3,7-diamino-N-methylphenothiazine sulfone; 2,7-diamino-9-fluorenone and 2,4,6,8-tetramethyl-3,7-diaminothioxanthene sulfone.

Abstract: Epoxy resin compositions for sealing semiconductor elements are disclosed and include an epoxy resin, a maleimide-modified siloxane compound represented by the formula (1) and an allylphenol-novolac resin represented by the formula (2) as a curing agent, and demonstrate low stress, high heat resistance and moldability. ##STR1## wherein, R.sub.1 denotes a methylene group a phenylene group or a substituted phenylene group,R.sub.2 denotes a methyl group, a phenyl group or a substituted phenyl group,n denotes 1 when R.sub.1 denotes phenylene or substituted phenylene groups, or 3 or 4 when R.sub.1 denotes a methylene group,m denotes an integer of from 1 to 100,l denotes an integer of from 1 to 100, and.kappa. denotes an integer of from 1 to 100.

Abstract: A thermosetting resin composition contains (A) an imide compound having a maleimide group, (B) an epoxy resin, (C) a phenolic resin, and optionally, (D) an aromatic polymer/organopolysiloxane copolymer. Component (B) and/or (C) includes a compound containing a naphthalene ring having an allyl group and preferably, a compound containing a naphthalene ring and a double bond conjugated with an aromatic ring. The composition is easily workable and cures to products having improved heat resistance, low thermal expansion, and low water absorption.

Abstract: A halogen free casting resin suitable for covering electron devices with a fire retardant material contains an acidic ester of an hydroxy-functional phosphor compound and an organic anhydride. A stable mixture can be generated from the acidic ester and the hardener component of the casting resin, and further used for the hardening of epoxides resins. The acidic ester is chemically integrated in the epoxide resin matrix in a stable mixture, thereby improving the long term fire-retardancy of the casting resin molding compound without increasing the volatility of the mixture.

Abstract: An epoxy resin composition for sealing semiconductor elements comprising o-cresol-novolak type epoxy resins, curing agents, curing accelerators, plasticizer and a high performance epoxy resin selected from a group consisting of epoxy resins represented by the formulas (I-a), (I-b) and (I-c) is disclosed.Use of the high performance epoxy resin in an amount of from 0.1 to 20.0% by weight improves the heat and moisture resistance of the epoxy resin composition. ##STR1## wherein, R.sub.1 and R.sub.2 represent independently H or (CH.sub.2) nCH.sub.3 radical, andn represents 0 or an integer of 1 above.

Abstract: Curable compositions contain a low molecular weight polyphenylene ether and a polyepoxide composition containing brominated and non-brominated bisphenol polyglycidyl ethers, in combination with further components including specific catalysts. Said compositions are preferably free from hardeners for epoxy resins. They may be used in the preparation of bonding sheets which are useful in the manufacture of multilayer printed circuit assemblies and which have excellent physical and electrical properties.

Abstract: A cationic electrodeposition paint composition suitable to be coated on a road wheel of an automotive vehicle. The paint composition is composed of an acrylic cationic resin (A), a urethanated epoxy cationic resin (B) a hardner resin (C) of a blocked isocyanate, and a cationic cross-linked resin particulate (D) having an average particle size ranging from 0.01.mu. to 1.mu.. In the paint composition the acrylic cationic resin (A), the urethanated epoxy system cationic resin (B), the blocked isocyanate hardner resin (C) and the cationic cross-linked resin particulate are respectively in amount of 20 to 70 parts by weight, 5 to 50 parts by weight, 10 to 40 parts by weight and 1 to 20 parts by weight relative to 100 parts by weight of a total solid content of the resins and particulate (A), (B), (C) and (D), thereby improving the corrosion resistance of the paint composition to the cut edge portion of the road wheel and the weatherability of coated paint film.

Abstract: Curable compositions contain a low molecular weight polyphenylene ether and a polyepoxide composition containing brominated and non-brominated bisphenol polyglycidyl ethers, in combination with further components including specific catalysts. Said compositions are preferably free from hardeners for epoxy resins. They may be used in the preparation of bonding sheets which are useful in the manufacture of multilayer printed circuit assemblies and which have excellent physical and electrical properties.

Abstract: An epoxy resin powder coating composition having excellent thermal resistance, mechanical strength, hardening speed and storage stability which comprises an epoxy resin mixture comprising a bisphenol type epoxy resin and a polyfunctional epoxy resin having at least three epoxy groups in the molecule; a hardener comprising a mixture of dicyandiamide and a compound represented by formula (I) below, and a filler: ##STR1## wherein, R.sup.1 represents an alkyl group or an aryl group, and preferably represents a phenyl group from the view of storage stability; and R.sup.2 represents a cyanoethyl group, a vinyl group, or a phenyl group.The powder coating composition is suitably used in fixing stator coils or armature coils in motors or generators.

Abstract: An epoxy resin powder coating composition comprises 100 parts by weight of bisphenol A mixed epoxy resin having number average molecular weight from 1,700 to 4,500 comprising a bisphenol A epoxy resin (A) having a number average molecular weight from 2,500 to 8,000 and a bisphenol A epoxy resin (B) having a number average molecular weight from 300 to 1,000 (C) a novolak epoxy resin 5 to 20 parts by weight of polyvinyl butyral resin or polyviny formal resin, a hardener, and a filler.

Abstract: Curable compositions containing a reaction product of at least one bisphenol polyglycidyl ether, at least one epoxidized novolak and at least one brominated bisphenol, in combination with a polyphenylene ether and further components including specific catalysts and hardeners, may be used in the preparation of laminates useful as printed circuit boards and having excellent physical and electrical properties.

Abstract: An epoxy resin bonding composition containing two different epoxy resin as a liquid admixture, a curing agent and a polyamide powder is disclosed. The bonding composition may be used, for example, to bond a ferrite magnetic to a motor yoke. One of the epoxy resins is an unmodified glycidyl ether of bisphenol A, bisphenol F or bisphenol AD. The other epoxy resin is an urethane-modified or glycol-modified glycidyl ether of bisphenol A, bisphenol F or bisphenol AD. The polyamide powder has an average particle size of 150 .mu.m or less and a melting of at least 170.degree. C. and is present in an amount 1-50 parts by weight per 100 parts by weight of liquid epoxy resin admixture.

Abstract: A resin composition especially suited to the resin transfer molding and wet filament winding processes is composed of epoxide compounds and one or more aromatic amine hardeners wherein the blend of epoxide compounds is (i) a diglycidyl ether of the reaction product of a bisphenol and a blend of (a) a diglycidyl ether of bisphenol A other than that of (i) and (b) a halohydrin having about two epoxy groups per molecule, (ii) a copolymer of ethyl hexyl acrylate and glycidyl methacrylate and (iii) a neopentyl glycol digylcidyl ether. This composition has a low viscosity, and when cured, exhibits high toughness and mechanical strengths useful in making high performance composites.

Abstract: A conductive die attach composition containing no solvent and substantially no ionic impurities which comprises:(a) an epoxy resin system comprising (i) at least one low viscosity epoxy resin; and (ii) at least one epoxy resin hardener;(b) at least one unsaturated monomer which, when polymerized, is not capable of reacting with said epoxy resin system;(c) at least one free radical initiator for polymericing said unsaturated monomer; and(d) finely divided silver particles.

Abstract: Curable compositions containing a polyphenylene ether and a polyepoxide composition containing brominated and non-brominated bisphenol polyglycidyl ethers, in combination with further components including specific catalysts and hardeners, may be used in the preparation of laminates useful as printed circuit boards and bonding sheets therefor and having excellent physical and electrical properties.

Abstract: A powder coating composition suitable for slot insulation is disclosed which includes an epoxy resin containing at least 60% by weight of a mixture of a first glycidyl ether of bisphenol A having a number average molecular weight of 2500-8000 with a second glycidyl ether of bisphenol A having a number average molecular weight of 350-1700, the mixture having a number average molecular weight of 1600-4600, a carboxyl group-terminated polyester resin in an amount of 5-100 parts by weight per 100 parts by weight of the epoxy resin, a curing agent, and an inorganic filler in an amount of 10-80% by weight.

Abstract: Curable compositions containing a reaction product of at least one bisphenol polyglycidyl ether, at least one epoxidized novolak and at least one brominated bisphenol, in combination with a polyphenylene ether and further components including specific catalysts and hardeners, may be used in the preparation of laminates useful as printed circuit boards and having excellent physical and electrical properties.

Abstract: An epoxy resin powder coating composition which comprises:(A) an epoxy resin comprising mainly of a bisphenol A epoxy resin mixture of (a) a bisphenol A epoxy resin having a number average molecular weight of from 2,500 to 8,000 and (b) a bisphenol A epoxy resin having a number average molecular weight of from 350 to 1,700, said mixture having a number average molecular weight of from 1,700 to 4,500;(B) rubber powder in an amount of 2 to 30 parts by weight per 100 parts by weight of said epoxy resin (A);(C) at least one hardener; and(D) a filler.The coating composition is particularly useful for the insulation of slots for motor rotors, exhibiting excellent thermal resistance, adhesiveness, impact resistance and coverage.