Abstract: An epoxy resin adhesive including at least one epoxy resin in the resin component, at least one adduct AD including primary amino groups which is free-flowing at room temperature and is formed from (i) at least one polyepoxide and (ii) at least one amine of the formula (I) and optionally further amines, and additionally at least one accelerator B having at least one dimethylamino group in the hardener component, and a total of at least 50% by weight of at least one inorganic filler. The epoxy resin adhesive has low odor and good processibility, rapidly builds up strength at room temperature and under cold conditions and, after curing, has high strengths, especially particularly high compressive strengths, and high bonding forces to substrates such as steel, carbon fiber composites (CRP) and concrete.

Abstract: A method of manufacturing an electronic package is disclosed. The described method includes (a) placing an electronic component on at least one layer structure; (b) encapsulating the electronic component by an encapsulant in a pressureless way; and (c) forming at least one further layer structure at the layer structure to thereby form a stack beneath the encapsulated electronic component. A further described electronic package includes (a) a stack comprising at least one layer structure and at least one further layer structure; (b) an electronic component being placed on the stack; and (c) an encapsulant encapsulating the electronic component, wherein the encapsulant has been formed in a pressureless way. Further described is an electronic device comprising such an electronic package.

Abstract: The present invention concerns new precursors of recyclable cross-linked diene elastomers comprising at least one furanyl group along the chain and comprising chain-end units with furanyl groups, their use in the preparation of said recyclable elastomers and their process of preparation. The invention also concerns new recyclable cross-linked diene elastomers, their preparation process and their uses.

Abstract: An epoxy resin, comprising an epoxy compound A that has at least two mesogenic structures and at least one phenylene group, and an epoxy compound B that has at least two mesogenic structures and at least one divalent biphenyl group.

Abstract: A semiconductor device of an embodiment includes: a wiring board; a semiconductor chip mounted on the wiring board; and a resin-containing layer bonded on the wiring board so as to fix the semiconductor chip to the wiring board. The resin-containing layer contains a resin-containing material having a breaking strength of 15 MPa or more at 125° C.

Abstract: The present invention is a solventless one liquid type cyanate ester-epoxy composition comprising: (A) a multifunctional cyanate ester, or mixture thereof, of formula (1), wherein an average cyanate group number is 2.5 or more; (B) a multifunctional liquid epoxy resin, or mixture thereof, of formula (2), wherein an average epoxy group number is 2.5 or more, and (C) an amine latent curing agent. [ Average ? ? cyanate ? ? group ? ? number ] = ? i = 1 n ? ? ( Ai × Xi ) 100 Formula ? ? ( 1 ) Ai is a cyanate group number of component i, and Xi is a content ratio of component i (percent by mass) in the formula (1). [ Average ? ? epoxy ? ? group ? ? number ] = ? k = 1 n ? ? ( Bk × Yk ) 100 Formula ? ? ( 2 ) Bk is an epoxy group number of component k, and Yk is a content ratio of component k (percent by mass) in the formula (2).

Abstract: Curable compositions comprising a benzoxazine component, a polyamine component and an ortho-dihydroxyaryl component are described. The compositions may be cured to produce compositions useful in coating, sealants, adhesive and many other applications.

Abstract: Curable compositions comprising a benzoxazine component, a polyamine component and a fluoropolymer component are described. The compositions may be cured to produce compositions useful in coating, sealants, adhesive and many other applications.

Abstract: A low dielectric resin varnish composition for laminated printed circuit boards, wherein the resin composition includes (A) Dicyclo-pentadiene-Phenolic Novolac resin (abbreviated as DCPD-PN); or (B) at least one kind of dicyclopentadiene Phenolic Novolac Epoxy resins(DCPD-PNE, referred to as Resin 1); or (C) a novel Dicyclopentadiene-Dihydrobenzoxazine resin (DCPD-BX, referred to as Resin 2); and (D) Flame retardant agent, curing agent and accelerating agent solutions.

Abstract: The invention provides an improvement to the useable lifetimes of phenolic-epoxy, phenolic-benzoxazine, phenolic-epoxy-benzoxazine mixtures and other phenolic mixtures through the use of protected phenolics, where a phenolic compound, polymer, or resin is released on demand by the addition of a deblocking agent.

Abstract: A composition is disclosed, which comprises a hydroxyaromatic-aldehyde resole resin comprising an aldehyde and a hydroxyaromatic compound, modified with a urea-aldehyde condensate. The hydroxyaromatic-aldehyde resole resin is prepared without ammonia or a primary amine and the composition does not contain a triazone or a substituted triazone compound. The composition has improved premix stability, improved cure efficiency, comparable tensile strength, and lower volatiles than the hydroxyaromatic-aldehyde resole resin unmodified with a urea-aldehyde condensate. Also disclosed are articles prepared therefrom.

Abstract: A method of using olefin containing nanostructured chemicals and silanol containing nanostructured chemicals as high temperature resins is described. Vinyl containing nanostructured chemicals are particularity effective in thermosets as they control the motions of polymer chains, and segments, at the molecular level. Silanol containing nanostructured chemicals are particularity effective in thermosets containing polar groups as the silanol can enhance the reactivity of these groups. Because of their tailorable compatibility with fluorinated polymers, nanostructured chemicals can be readily and selectively incorporated into polymers by direct blending and polymerization processes. The incorporation of a nanostructured chemical into a polymer favorably impacts a multitude of polymer physical properties. Properties most favorably improved are heat distortion and flammability characteristics, permeability, optical properties, texture, feel and durability.

Abstract: A curable composition comprising a) an epoxy resin containing on average more than one epoxy group per molecule, and b) as curing agent a composition comprising b1) 40-100 wt % of a reaction product from the reaction of b1a) at least one diglycidyl- and/or at least one monoglycidylether with b1b) a composition comprising a volatile monoamine and a polyamine, said composition b1b) is used in an amount to provide an excess amino groups relative to epoxy groups from b1a), and whereby the excess of monoamine is removed off from the reaction product, b2) 0-60 wt % of a polyamine, and b3) 0-25 wt % of a polyphenol novolac, and whereby the sum of components b1), b2) and b3) is 100 wt %, providing long pot life combined with fast cure times at low temperatures, thus making said compositions especially useful for marine and offshore coatings, industrial maintenance, construction, tank and pipe linings, adhesive, automobile and electrical potting applications.

Abstract: A composition is disclosed, which comprises a hydroxyaromatic-aldehyde resole resin comprising an aldehyde and a hydroxyaromatic compound, modified with a urea-aldehyde condensate. The composition has improved premix stability, improved cure efficiency, comparable tensile strength, and lower volatiles than the hydroxyaromatic-aldehyde resole resin unmodified with a urea-aldehyde condensate. Also disclosed are articles prepared therefrom.

Abstract: The present invention provides a bifunctional phenylene ether oligomer compound having a thermosetting functional group at each terminal, an epoxy resin containing the above oligomer compound and a use thereof. That is, it provides a sealing epoxy resin composition for sealing an electric part, an epoxy resin composition for laminates, a laminate, a printed wiring board, a curable resin composition and a photosensitive resin composition. The resins and resin compositions of the present invention are used in electronics fields in which a low dielectric constant, a low dielectric loss tangent and high toughness are required and also used for various uses such as coating, bonding and molding.

Abstract: The invention relates to a method of making an acrylic graft polymer, especially a urethanized acrylic graft polymer. The method of the invention requires an ethylenically unsaturated monomer mixture (a) comprising a monomer (ai) of a particular structure having at least one cyclic carbonate group and the polymerization of the monomer mixture (a) under free radical polymerization conditions to make an acrylic backbone polymer (b) comprising one or more cyclic carbonate functional groups (bi). At least one grafting moiety (c) is then provided, said grafting moiety (c) comprising at least one amine group (ci) selected from primary amines, secondary amines, and mixtures of both primary and secondary amines. The grafting moiety (c) is then grafted onto acrylic backbone polymer (b) via reaction between the at least one amine group (ci) and cyclic carbonate functional groups (bi) so as to make an urethanized acrylic graft polymer.

Abstract: The cure rate of phenol-aldehyde resins is accelerated by conjoint use of a cyclic carbonate cure accelerant and an amine cure accelerant. The cure rate is accelerated still further by addition of a resorcinol source to resin comprising a cyclic carbonate and an amine cure accelerator. Also, cured resins made in accordance with the method.

Abstract: The nanoscopic dimensions of polyhedral oligomeric silsesquioxanes (POSS) and polyhedral oligomeric silicates (POS) materials ranges from 0.7 nm to 5.0 nm and enables the thermomechanical and physical properties of polymeric materials to be improved by providing nanoscopic reinforcement of polymer chains at a length scale that is not possible by physically smaller aromatic chemical systems or larger fillers and fibers. A simple and cost effective method for incorporating POSS/POS nanoreinforcements onto polymers via the reactive grafting of suitably functionalized POSS/POS entities with polymeric systems amenable to such processes is described. The method teaches that the resulting POSS-grafted-polymers are particularly well suited for alloying agents by nongrafted POSS entitles such as molecular silicas. The successful alloying of POSS-polymers is aided because their interfacial tensions are reduced relative to non-POSS containing systems.

Abstract: The present invention provides a new class of materials effective as accelerators for curing anaerobic adhesives. The addition of these materials into anaerobic adhesives as a replacement for conventional curatives, such as APH and/or toluidines, surprisingly provides at higher cure speeds and comparable physical properties for the reaction products formed therefrom.

Abstract: A method of using nanostructured chemicals as alloying agents for the reinforcement of polymer microstructures, including polymer coils, domains, chains, and segments, at the molecular level. Because of their tailorable compatibility with polymers, nanostructured chemicals can be readily and selectively incorporated into polymers by direct blending processes. The incorporation of a nanostructured chemical into a polymer favorably impacts a multitude of polymer physical properties. Properties most favorably improved are time dependent mechanical and thermal properties such as heat distortion, creep, compression set, shrinkage, modulus, hardness and abrasion resistance. In addition to mechanical properties, other physical properties are favorably improved, including lower thermal conductivity, fire resistance, and improved oxygen permeability.

Abstract: The present invention provides a new class of materials effective as accelerators for curing anaerobic adhesives. The addition of these materials into anaerobic adhesives as a replacement for conventional curatives, such as APH and/or toluidines, surprisingly provides at least comparable cure speeds and physical properties for the reaction products formed therefrom.

Abstract: The present invention provides a crosslinking agent which may have reactive benzoxazine groups prepared from (a) at least one aromatic compound, (b) at least one aminotriazine compound, and (c) at least one other compound having active hydrogen groups reactive with aminoplast compound (b). The crosslinking agent is essentially free of hydroxyl functionality and has a glass transition temperature of at least 25° C. The present invention is further directed to a method for preparing the above-described crosslinking agent, and a curable powder coating composition comprising a mixture of (A) a polymer having functional groups reactive with aminotriazine and/or benzoxazine groups having a glass transition temperature of at least 30° C.; and (B) the above crosslinking agent. Multilayer composite coating compositions are also provided including a basecoat deposited from a film-forming composition and a topcoat over the basecoat, deposited from the curable powder coating composition described above.

Abstract: The invention relates to a method of making an acrylic graft polymer, especially a urethanized acrylic graft polymer. The method of the invention requires an ethylenically unsaturated monomer mixture (a) comprising a monomer (ai) of a particular structure having at least one cyclic carbonate group and the polymerization of the monomer mixture (a) under free radical polymerization conditions to make an acrylic backbone polymer (b) comprising one or more cyclic carbonate functional groups (bi). At least one grafting moiety (c) is then provided, said grafting moiety (c) comprising at least one amine group (ci) selected from primary amines, secondary amines, and mixtures of both primary and secondary amines. The grafting moiety (c) is then grafted onto acrylic backbone polymer (b) via reaction between the at least one amine group (ci) and cyclic carbonate functional groups (bi) so as to make an urethanized acrylic graft polymer.

Abstract: A one part, several-months-useful-shelf-life epoxy material suitable for potting and sealing electronic components, and which is compatible with the high, approximately 255° C. to 275° C. temperatures required for soldering modem lead-free solders comprises an intimate mixture of the following components: approximately 2 to 13 per cent by weight of diglycidyl ether bisphenol A resin; approximately 40 to 70% phenol formaldehyde resin and the following further components [(2-methylphenoxy)methyl]-oxirane or o-cresol glycidyl ether) 0.5-8% by weight; polypropyleneglycol-glycidyl ether resin (plasticizer) 2-10% by weight; cycloaliphatic polyamine (catalyst) 4-15% by weight; kaolin clay (filler) 2-20% by weight; magnesium alumino silicate (filler) 2-15% by weight; Sb2O3 (filler) 4-5% by weight, and hydrated Al2O3 (filler) 0-15% by weight.

Abstract: The present invention provides a crosslinking agent having reactive benzoxazine groups which is the ungelled reaction product of (a) at least one mono-hydroxy aromatic compound and (b) at least one aminotriazine compound having one or less non-alkylated NH group present in a molar ratio of reactant (a) to reactant (b) ranging from 1.0 to 3.0: 1.0, provided that where reactant (a) is a single ring monohydroxy aromatic compound, the molar ratio of reactant (a) to reactant (b) ranges from 1.0 to 1.8:1.0 and from 2.2 to 3.0:1.0. The crosslinking agent is essentially free of hydroxyl functionality and has a glass transition temperature of at least 25° C. The present invention is further directed to a method for preparing the above-described crosslinking agent.

Abstract: Compounds active as accelerators for curable epoxy and polyurethane systems, those compounds having been prepared by means of a transamination reaction by reacting (a) a substituted phenolic compound (Mannich base) having at least one substituent of formula R1(R2)N—CH(R3)—  (A), wherein R1 and R2 are each independently of the other linear or branched C1-4alkyl and R3 is hydrogen, methyl, ethyl or phenyl, with (b) a compound of formula R4(R5)N—CnH2n—(NH—CnH2n)q—NH2  (B), wherein R4 and R5 are each independently of the other C1-C6alkyl or together form a radical of formula —(CH2)5— or —(CH2)2—O—(CH2)2—, n is an integer from 2 to 5 and q is zero, 1, 2 or 3, and the compound obtained or the compounds present in the mixture obtained has/have on average, per molecule, at least one substituent of formula (R4)(R5)N—CnH2n—(NH—CnH2n)q—NH—CH(R3)—, and the use of those compounds as acceler

Abstract: A melamine-containing resin modified with a cyclic urea prepolymer comprising urea, formaldehyde and ammonia or a primary amine. The prepolymer-modified melamine-containing resin provides useful binders alone, or when combined or coreacted with other resins. Products prepared with the binder include wood composites such as particleboard and medium density fiberboard.

Abstract: The invention provides a resin composition comprising (A) a polymer comprising at least 1 primary carbamate functional group and 1 or more quaternary ammonium groups, and (B) a carbamate functional reactive additive that is generated in situ during the production of polymer (A).

Abstract: The preparation of phenol-formaldehyde and melamine-formaldehyde resin-based binders extended with a cyclic urea-formaldehyde prepolymer and to products prepared using the binders. More particularly, the invention relates to a cyclic urea prepolymer comprising urea, formaldehyde, and ammonia or a primary amine which, when added to a phenol-formaldehyde or melamine-formaldehyde based resin, results in a useful binder for the manufacturer numerous articles.

Abstract: The preparation of phenol-formaldehyde and melamine formaldehyde resin-based binders extended with a cyclic urea-formaldehyde prepolymer and to products prepared using the binders. More particularly, the invention relates to a cyclic urea prepolymer comprising urea, formaldehyde, and ammonia or a primary amine which, when added to a phenol-formaldehyde or melamine-formaldehyde based resin, results in a useful binder for the manufacturer numerous articles.

Abstract: Metal compounds of pseudohalogenides and their use as curing agents for epoxy compounds which curing agents can be produced by mixing the reactants in aqueous solution and are distinguished by a long processibility time at temperatures up to 100° C. as well as by very short curing times at temperatures in the range of 120 to 160° C.

Abstract: A flexible encapsulating material resulting from a mixture that includes at least one epoxy novolak resin and at least two other epoxy compounds wherein the material has a percent hardness change of less than 20% after thermal aging of 504 hours at 140° C. The epoxy novolak resin preferably has less than 3 epoxy groups per molecule. A further embodiment is an electronic component encapsulated with a flexible material resulting from combining a two part system wherein a first part includes an epoxy novolak resin and at least two other epoxy resins and the second part includes at least one amine. An additional embodiment is a method for flexibly encapsulating an electronic component comprising applying to the component a mixture comprising an epoxy novolak resin having less than 3 epoxy groups per molecule and at least one other epoxy compound.

Abstract: The invention provides a cathodic electrocoat coating composition having (A) a polymer comprising at least one primary carbamate group and at least one cationic salting site, (B) a curing agent having groups that are reactive with said functional groups on (A), and (C) a reactive additive comprising at least one compound having a molecular weight of from 131 to 2000 and comprising at least one primary carbamate group and at least one alkyl group selected from the group consisting of branched alkyl groups of from 5 to 30 carbons, straight chain alkyl groups of more than 10 carbons, and mixtures thereof, wherein one or both of (A) and (B) comprise groups that are reactive with the primary carbamate group of (C).

Abstract: The preparation of phenol-formaldehyde and melamine-formaldehyde resin-based binders extended with a cyclic urea-formaldehyde prepolymer and to products prepared using the binders. More particularly, the invention relates to a cyclic urea prepolymer comprising urea, formaldehyde, and ammonia or a primary amine which, when added to a phenol-formaldehyde or melamine-formaldehyde based resin, results in a useful binder for the manufacturer numerous articles.

Abstract: The preparation of phenol-formaldehyde and melamine-formaldehyde resin-based binders extended with a cyclic urea-formaldehyde prepolymer and to products prepared using the binders. More particularly, the invention relates to a cyclic urea prepolymer comprising urea, formaldehyde, and ammonia or a primary amine which, when added to a phenol-formaldehyde or melamine-formaldehyde based resin, results in a useful binder for the manufacturer numerous articles.

Abstract: The present invention provides an epoxy resin composition, comprising:(A) a phenol epoxy resin represented by the following formula (I) ##STR1## wherein each R.sup.1 is the same or different and is independently selected from the group consisting of hydrogen, C.sub.1 to C.sub.6 hydrocarbyl groups, C.sub.6 to C.sub.10 aromatic groups, and C.sub.1 to C.sub.6 hydrocarbyl-substituted C.sub.6 to C.sub.10 aromatic groups,each R.sup.2 is the same or different and is independently selected from the group consisting of hydrogen, C.sub.1 to C.sub.6 hydrocarbyl groups, C.sub.6 to C.sub.10 aromatic groups, and C.sub.1 to C.sub.6 hydrocarbyl-substituted C.sub.6 to C.sub.10 aromatic groups, ##STR2## wherein R.sup.3 is selected from the group consisting of hydrogen, C.sub.1 to C.sub.6 hydrocarbyl groups, C.sub.6 to C.sub.10 aromatic groups, and C.sub.1 to C.sub.6 hydrocarbyl-substituted C.sub.6 to C.sub.10 aromatic groups, each R.sup.

Abstract: The stilbene epoxy resin having two different aryl groups and an epoxy resin mixture including this stilbene epoxy resin have lower melting points than those of the stilbene epoxy resin having two identical aryl groups and the epoxy resin mixture of the latter stilbene epoxy resin. Compared with the conventional resins, the present resin or resin mixture has improved working and molding properties, which shortens the time required for the molding and working process, resulting in economic advantages and a preferred affect on productivity. The present epoxy resin or resin mixture is preferably used as an adhesive, a coating, an insulating material, an electrical or electronic material for laminated sheets or the like. It is especially suited for use as material for encapsulating electronic parts.

Abstract: A composition useful as a die-attach adhesive, polymer bump or encapsulant comprises from about 5-100% by weight of a base resin and from zero to 95% by weight of a particulate filler such as silver, wherein the base resin contains (a) from 10-95 parts by weight of a cycloaliphatic epoxy-functional siloxane, (b) from about 5-90 parts by weight of a non-silicon-containing polyepoxy resin, .COPYRGT. from about 0.1-3 parts by weight of an iodonium salt, (d) from zero to about 3 parts by weight of a copper compound and, optionally, a silane adhesion promotor and/or an elastomeric toughener.

Abstract: A composition useful as a powder coating comprises an epoxy resin and a novolak compound or resin having a structure obtained from the reaction of a substituted phenol such as cresol and an aldehyde to form a substituted bis(hydroxymethyl) phenol intermediate which is then reacted with a polyhydroxyphenol containing adjacent hydroxyl groups such as catechol to yield a polyhydroxyphenol-endcapped novolak compound or resin.

Abstract: An object is to provide hardened products having excellent water resistance and mechanical strength, and an epoxy resin and an epoxy resin composition for use in the production thereof. An epoxy resin obtained by the glycidylation of a novolak type resin which is prepared by the condensation of biphenyls with phenols and naphthols, and a resin composition containing said epoxy resin and hardened products thereof.

Abstract: The present invention relates to a low VOC solvent based adhesive comprising a mixture of at least two organic solvents and a thermoplastic resin. Desirably the adhesive has a flash point of at least 100.degree. F. when measured in accordance with ASTM D3828-87. The solvent blend of the low VOC solvent based adhesive of the instant invention volatilizes at substantially reduced rates as compared to conventional solvent blends in solvent based adhesives. Furthermore, this novel low VOC solvent based adhesive is easy to apply, cost effective, and cures within a reasonable time without the use of heat, ultraviolet light or other mechanical devices. In addition, the novel low VOC solvent based adhesive has good storage stability in metal or non-metal containers.

Abstract: A curing catalyst for use in epoxy resin, said curing catalyst being a metal salt complex of an adduct between polyepoxide and imidazoles; and a heat curing coating composition prepared by mixing the above curing catalyst with a coating composition containing an epoxy group-containing compound.

Abstract: The present invention relates to an epoxy composition represented by the formula (I) below, wherein G is a glycidyl group or a halogen atom. It is produced by reacting a halogenated polyhydric phenol compound with epihalohydrin in the presence of an alkali metal hydroxide. It is incorporated into a resin to render it flame retardant.

Abstract: A polyhydroxystyrene having a 2,4-diamino-s-triazinyl group substituted for 1-50 mol % of its hydroxyl group and a weight average molecular weight of 3,000-50,000 is provided. A negative radiation-sensitive resist composition comprising the polymer, preferably along with a photo-acid generator and a crosslinking agent has high resolution and developability, affords a resist pattern of rectangular profile, and is shelf stable. The composition is thus very useful as resist material for LSI manufacture.

Abstract: An epoxy resin composition contains an epoxy resin as a substratal resin and incorporates therein a polyallylphenol curing agent. The composition may also contain a polyphenol compound. The epoxy resin may have a naphthalene skeleton. The epoxy resin composition may also include a blend of two or more epoxy resins.

Abstract: There is disclosed a self-disbursing curable epoxy resin composition comprising the addition product of reactants comprising (a) 1.0 reactive equivalent of an epoxy resin, (b) from about 0.40 to 0.95 reactive equivalents of a polyhydric phenol, and (c) from about 0.005 to 0.5 reactive equivalents of an amine-epoxy adduct comprising the addition product of reactants comprising 1.0 reactive equivalent of an aromatic polyepoxide and from about 0.3 to 0.9 reactive equivalents of a polyoxyalkyleneamine.

Abstract: An epoxy resin composition comprising (A) an epoxy resin represented by the general formula (1) ##STR1## wherein each R.sub.1, independent of the other, represents hydrogen, a hologen atom, an alkyl group having 1 to 6 carbon atoms, substituted- or nonsubstituted-phenyl groups, and X represents ##STR2## and n represents an integer of 0 to 4, and (B) a curing agent, which composition provides a cured product exhibiting low hygroscopicity and high adhesiveness.

Abstract: There is disclosed a self-dispersing curable epoxy resin composition comprising the addition product of reactants comprising (a) 1.0 reactive equivalent of an epoxy resin, (b) from about 0.40 to 0.95 reactive equivalents of a polyhydric phenol, and (c) from about 0.005 to 0.5 reactive equivalents of an amine-epoxy adduct comprising the addition product of reactants comprising 1.0 reactive equivalent of a polyepoxide and from about 0.3 to 0.9 reactive equivalents of a polyoxyalkyleneamine having the structural formula:R.sub.1 --O--R.sub.2 --CH.sub.2 CH(R.sub.3)--X--R.sub.4 --NH2wherein:R.sub.1 designates a monovalent organic radical selected from the group consisting of C.sub.1 to C.sub.12 aliphatic, alicyclic or aromatic hydrocarbons, andR.sub.2 represents a polyoxyalkylene chain having the structural formula:(CH.sub.2 --CH.sub.2 --O).sub.a --(CH.sub.2 --CH(R.sub.5)--O).sub.bwherein:R.sub.5 is a monovalent organic radical selected from the group consisting of C.sub.1 to C.sub.

Abstract: Disclosed is a thermosetting resin composition comprising cyanate resin, a compound containing at least one or more than one of a phenolic hydroxyl radical and an epoxy resin, wherein said resin has excellent adhesive and heat resistant properties while at the same time possessing a low hardening contraction rate and contributing to higher dimensional stability, and method of making the same.

Abstract: An epoxy resin composition for sealing a photosemiconductor element includes(A) an epoxy resin component which comprises an epoxy resin having at least three epoxy groups per molecule,(B) a phenolic resin component which is represented by the following general formula (I) and has a phenolic hydroxyl group equivalent weight (g/eq) of 200 to 800, and(C) a cure accelerator component, ##STR1## wherein n is an integer of from 0 to 14, the phenolic resin component being a mixture of at least two phenolic resins represented by the general formula (I) with at least two different values of n, the resin with n=0 being not more than 20% by weight of the phenolic resin component;and a photosemiconductor device is sealed with the epoxy resin composition.