Abstract: An epoxy resin composition which comprises a curable epoxy resin, a curing agent, an inorganic filler, and at least one copolymer selected from copolymers obtained by an addition reaction between aromatic polymers containing one or more epoxy groups and one or more alkenyl groups and the specific organopolysiloxanes; copolymers obtained by an addition reaction between aromatic polymers containing one or more epoxy groups and the specific amino group-containing organopolysiloxanes.

Abstract: A novel organic silicon compound and hydrolyzate thereof are provided in which an alkoxysilane having an alkoxy radical attached to the silicon atom is attached to a polyester through an alkylene radical. They are useful as a plasticizer for rubber.

Abstract: A curable epoxy resin is blended with (a) an alkenyl group-containing epoxidized novolak resin/organopolysiloxane copolymer and (b) a polyimide resin in addition to a curing agent and an inorganic filler. The resulting epoxy resin composition can be cured both under moisture-free conditions and even under moist conditions without inducing a crack. It is suitable for the encapsulation of semiconductor devices as well as for molding and powder coating.

Abstract: The fluorine-substituted organopolysiloxane as the principal ingredient of the inventive silicone rubber composition has vinyl groups to serve as the cross-linking points at the molecular chain terminals while at least the penultimate siloxane unit or the silicon atom adjacent to the terminal silicon atom has no fluorine-substituted hydrocarbon group bonded to the silicon atom. Being freed from the steric hindrance due to the bulky fluorine-substituted hydrocarbon group bonded to the adjacent silicon atom, the vinyl group bonded to the terminal silicon atom can pertain to the cross-linking reaction much easier than otherwise so that the silicone rubber composition of the invention containing an organic peroxide or a combination of an organohydrogenpolysiloxane and a platinum catalyst as a curing agent can be rapidly cured to give a cured silicone rubber article having excellent resistance against oils and organic solvents as well as mechanical properties.

Abstract: A rubber composition, which forms a vulcanizate having excellent surface properties such as pleasant feeling of touch and slipperiness or lubricity, comprises, in addition to conventional ingredients such as an ethylene-propylene copolymer, organopolysiloxane, reinforcing silica filler, process oil and curing agent, a powder of spherical particles, such as a poly(methyl silsesquioxane) powder, in the form having a particle diameter of 0.1 .mu.m to 50 .mu.m in a limited amount. The rubber composition forms a spongy rubber vulcanizate when vulcanized in the presence of a blowing agent which, by virtue of excellent surface properties, is useful as powder puffs for make-up.

Abstract: Acryl rubber foaming compositions comprising (A) an acrylic polymer prepared by copolymerizing an acrylate or methacrylate with a monomer having at least two aliphatic unsaturated bonds per molecule, (B) a pyrolytic organic foaming agent, and (C) an organic peroxide can be molded, cured and foamed into acryl rubber foams having improved heat insulation, heat resistance, weatherability, crack resistance, and oil resistance without a need for sulfur vulcanizer.

Abstract: Rubber vulcanizates having excellent oil resistance, heat resistance and cold resistance can be obtained from a rubbery copolymer which is a polymerization product of an acrylic monomer mixture of which the essential components are an organosiloxy-containing acrylate compound such as acryloxymethyl pentamethyl disiloxane and 3-acryloxypropyl pentamethyl disiloxane and an epoxy group- or halogen-containing monomer such as allyl glycidyl ether, glycidyl methacrylate and vinyl chloroacetate, optionally, with addition of an acrylate ester monomer such as ethyl acrylate, n-butyl acrylate and 2-methoxyethyl acrylate.

Abstract: The present invention provides a novel epoxy resin-based curable composition suitable for use as an encapsulating resin composition for semiconductor devices capable of being highly resistant against crack formation with low internal stress by curing and yet having very high heat conductivity and maintaining high glass transition temperature. The inventive composition comprises (a) 100 parts by weight of a curable epoxy resin blend which is a mixture of an epoxy resin and a curing agent therefor, (b) from 5 to 100 parts by weight of a block copolymer composed of at least one segment of an aromatic polymeric moiety, phenyl novolac, and at least one segment of an organopolysiloxane moiety having 30 to 200 silicon atoms and bonded to the aromatic polymeric moiety through a carbon-to-silicon linkage, and optionally (c) an inorganic filler which is preferably a silica filler such as powdered quartz in an amount not exceeding 1000 parts by weight.

Abstract: An epoxy resin composition which comprises a curable epoxy resin, a curing agent, an inorganic filler, and at least one copolymer selected from copolymers obtained by an addition reaction between aromatic polymers containing one or more epoxy groups and one or more alkenyl groups and the specific organopolysiloxanes; copolymers obtained by an addition reaction between aromatic polymers containing one or more epoxy groups and the specific amino group-containing organopolysiloxanes.

Abstract: Organosilicon compounds of the following formula, or hydrolyzates thereof, ##STR1## ps in which Rhu 1 l and Rhu 2 l are independently a hydrogen atom or an alkyl group having from 1 to 8 carbon atoms, m is an integer of from 1 to 8, and n is an integer of from 1 to 3. The compound is useful as a vulcanizing agent particularly for vulcanizable elastomer compositions comprising inorganic fillers.

Abstract: An epoxy resin composition which is adapted for use as an encapsulator of electronic or electric parts and which comprises an epoxy resin and a curing agent for the epoxy resin. A modified polymer obtained by reaction between an aromatic polymer and a fluorine-containing material is added to the epoxy resin, so that good characteristic properties are imparted to the resultant cured product.

Abstract: A foamable silicone rubber composition, comprising:(A) a polyorganosilphenylenesiloxane copolymer represented by Formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are each a particular monohydrocarbon group, and a and h are each an integer of 1 or more and have the relation of 1.gtoreq.a/b.gtoreq.0.05 and a+b.gtoreq.100,(B) an organosilicon compound containing a particular organosiloxy unit having a hydroxyl group,(C) a polyorganohydrogenosiloxane having at least two particular units having an Si--H bond, and(D) a platinum family metal catalyst.This composition can provide a foam with good mechanical strength.

Abstract: A silicone rubber composition composed of a high-molecular diorganopolysiloxane, a reinforcing silica filler and an organic peroxide as a curing agent is further compounded with a fluorine-containing low-polymeric compound such as poly(chlorotrifluoroethylene) and perfluorinated polyether compound of the formula F--[--CF(CF.sub.3)--CF.sub.2 --O--].sub.v --O--CF.sub.2 --CF.sub.3, in which v is 2 to 100, as well as fluoroalkyl-substituted organopolysiloxanes. The silicone rubber composition can give a cured silicone rubber product having greatly improved resistance against dynamic fatigue as in repeated cycles of stretching and relaxation.

Abstract: A self-adhering silicone composition comprising;(A) 100 parts by weight of an organopolysiloxane(B) 0.01 to 10 parts by weight of an organic peroxide represented by the formula (II): ##STR1## wherein R.sup.2 represents a hydrogen atom, an alkyl group or alkoxy group having 1 to 10 carbon atoms; R.sup.3 represents an alkyl group having 1 to 10 carbon atoms or a phenyl group; a is an integer of 1 to 3 and b is an integer of 0 to 2, provided that a+b=3; and c is an integer of 1 to 3 and d is an integer of 0 to 2, provided that 1.ltoreq.c+d.ltoreq.5.This composition can bring about strong and durable adhesion to substrates without use of any primers.

Abstract: While high-performance semiconductor devices encapsulated with a resin composition are subject to the problem of wrong operation due to the alpha-particles emitted from the trace amounts of radioactive impurities, e.g. uranium and thorium, contained in the silica filler incorporated in the resin composition, a means for solving this problem is provided by use of a silicon dioxide powder obtained by the pyrolysis of a volatilizable silicon compound free from radioactive impurities in an oxidizing condition and having an average particle diameter in the range from 0.5 to 100 .mu.m in place of the conventional silica fillers.