Abstract: Disclosed herein is a process for the selective hydrogenation of the carbon-carbon double bonds of an unsaturated, nitrile-group-containing polymer with hydrogen in the presence of a hydrogenation catalyst. An aqueous emulsion of the unsaturated, nitrile-group-containing polymer is used. Optionally, an organic solvent capable of dissolving or swelling the polymer is caused to exist at a volume ratio of the aqueous emulsion to the organic solvent in a range of from 1:3 to 1:0. A palladium compound is used as the hydrogenation catalyst. The aqueous emulsion is brought into contact with gaseous or dissolved hydrogen while maintaining an emulsified state.

Abstract: A catalyst comprising a high-molecular complex formed from a palladium compound and a nitrile group-containing polymer, and a method for hydrogenating a conjugated diene polymer which comprises selectively hydrogenating only a carbon-carbon double bond of the conjugated diene polymer using same.

Abstract: In a method for hydrogenating a nitrile group-containing unsaturated copolymer which comprises selectively hydrogenating only a carbon-carbon double bond of the nitrile group-containing unsaturated copolymer in solution, the improvement wherein a palladium complex represented by formulaPd(Y).sub.n (X).sub.mwherein Y denotes at least one neutral ligand, X denotes an anion, n is an integer of 1 to 4 and m is 0, 2 or 4,is used as a hydrogenation catalyst.

Abstract: Disclosed is a magnetic recording medium comprising a non-magnetic support and a magnetic layer composed mainly of a ferromagnetic powder and a binder, which is formed on one surface of the support, and an optional backcoat layer composed mainly of a non-magnetic powder and a binder, which is formed on the other surface of the support. At least one of the magnetic layer and the backcoat layer contains a compound having at least one >C.dbd.N.sup..sym. < bond in the molecule. When preparing the magnetic recording medium, the magnetic powder or non-magnetic powder may be surface-treated with the >C.dbd.N.sup..sym. < group-containing compound.

Abstract: A catalyst comprising a high-molecular complex formed from a palladium compound and anitrile group-containing polymer, and a method for hydrogenating a conjugated diene polymer which comprises selectively hydrogenating only a carbon-carbon double bond of the conjugated diene polymer using same.

Abstract: A nitrile group-containing, highly saturated copolymer rubber is disclosed, the copolymer chain of which is comprised of (1) 5 to 40% by weight of units of an unsaturated nitrile monomer, (2) 1 to 80% by weight of units of a monomer selected from a fluorine-free unsaturated carboxylic acid ester monomer and a fluorine-containing vinyl monomer and (3) up to 20% by weight of units of a conjugated diene monomer, with the balance being (4) units of a hydrogenated conjugated diene monomer, wherein the sum of the contents of the monomer units (1) and (2) is 30 to 90% and the sum of the contents of the monomer units (3) and (4) is 10 to 70% by weight. This copolymer rubber results in a rubber composition having an improved cold resistance.

Abstract: A nitrile group-containing, highly saturated copolymer rubber is disclosed, the copolymer chain of which is comprised of (1) 5 to 40% by weight of units of an unsaturated nitrile monomer, (2) 1 to 80% by weight of units of a monomer selected from a fluorine-free unsaturated carboxylic acid ester monomer and a fluorine-containing vinyl monomer and (3) up to 20% by weight of units of a conjugated diene monomer, with the balance being (4) units of a hydrogenated conjugated diene monomer, wherein the sum of the contents of the monomer units (1) and (2) is 30 to 90% and the sum of the contents of the monomer units (3) and (4) is 10 to 70% by weight. This copolymer rubber results in a rubber composition having an improved cold resistance.

Abstract: A rubber composition comprising a nitrile group-containing hydrocarbon rubber and a vulcanizing system, characterized in that the iodine value of said rubber does not exceed 120 and the pH of the tetrahydrofuran solution of said rubber is at least 5.

Abstract: A nitrile group-containing, highly saturated copolymer rubber is disclosed, the copolymer chain of which is comprised of (1) 5 to 40% by weight of units of an unsaturated nitrile monomer, (2) 1 to 80% by weight of units of a monomer selected from a fluorine-free unsaturated carboxylic acid ester monomer and a fluorine-containing vinyl monomer and (3) up to 20% by weight of units of a conjugated diene monomer, with the balance being (4) units of a hydrogenated conjugated diene monomer, wherein the sum of the contents of the monomer units (1) and (2) is 30 to 90% and the sum of the contents of the monomer units (3) and (4) is 10 to 70% by weight. This copolymer rubber results in a rubber composition having an improved cold resistance.

Abstract: A process for hydrogenating a conjugated diene polymer which comprises hydrogenating the carbon-carbon double bond of the conjugated diene polymer using a hydrogenation catalyst supported on a carrier, the carrier being an oxide of an element of Group IVa of the periodic table such as TiO.sub.2 or ZrO.sub.2.

Abstract: An anti-degrading rubber article to be used in contact with a mineral oil containing an oil modifier, at least that surface of said rubber article which is to come into contact with said mineral oil being composed substantially of a vulcanization product, obtained by using a sulfur vulcanization system, of a copolymer rubber having polymer chains consisting of(1) 10 to 60% by weight of units derived from an unsaturated nitride,(2) 2 to 30% by weight of units derived from a conjugated diene, and(3) 88 to 10% by weight of units derived from a copolymerizable ethylenically unsaturated monomer other than the unsaturated nitride and/or units resulting from the hydrogenation of units derived from a conjugated diene.

Abstract: For use in sealing semiconductors, an epoxy resin composition is provided which comprises an epoxy resin, a curing agent, a filler and a modifier, wherein the modifier is a diene polymer or acrylic polymer having an iodine number of not more than 120 or both included in an amount of 1 to 50 parts by weight per 100 parts by weight of the epoxy resin.

Abstract: A rubber article with excellent oil resistance and aging resistance to be used in contact with a polyolefin oil or a lubricating oil containing a polyolefin oil, at least the surface of the rubber article being contacted with said oil, said rubber article being composed substantially of a vulcanized product of a copolymer rubber comprising (1) 10 to 60% by weight of units derived from an unsaturated nitrile, (2) 0 to 30% by weight of units derived from a conjugated diene, and (3) 90 to 10% by weight of units derived from an ethylenically unsaturated monomer other than the unsaturated nitrile and/or units resulting from the hydrogenation of units derived from a conjugated diene.

Abstract: A heat-resistant and oil-resistant rubber composition comprising a nitrile group-containing rubber having an iodine value of not more than 120 and a nitrile group-containing liquid polymer having an iodine value of not more than 120.

Abstract: A belt comprising a copolymer rubber and fibers and having strong adhesion strength even after heat-aging in air or oil and repeated deformation. The copolymer rubber has in its polymer chain (1) 10 to 60% by weight of units derived from an unsaturated nitrile, (2) 0 to 30% by weight of units derived from a conjugated diene and (3) 10 to 90% by weight of units derived from an ethylenically unsaturated monomer other than unsaturated nitriles and/or units formed by hydrogenating units derived from a conjugated diene.

Abstract: An oil- and heat-resistant rubber composition comprising a nitrile group-containing hydrocarbon rubber having an iodine number of not more than 120 and a fluorine-containing rubber.

Abstract: An impact-resistant phenolic resin composition comprising 99 to 25% by weight of a phenolic resin and 1 to 75% by weight of a nitrile group-containing highly saturated polymer rubber whose amount of bound nitrile ranges from 10 to 60% by weight and having an iodine value not exceeding 120.

Abstract: A rubber composition having improved steam resistance comprising a nitrile group-containing hydrocarbon rubber having an iodine number of not more than 120, an organic peroxide vulcanizer and a crosslinking coagent, the amount of said crosslinking coagent being 8 to 30 parts by weight per 100 parts by weight of said rubber.

Abstract: A method of preventing degradation of vulcanized rubber materials used in the operation of oil and gas wells comprising forming said rubber material from a sulfur vulcanized composition comprising a copolymer rubber having in the polymer chain (I) 10 to 60% by weight of a unit from an unsaturated nitrile, (II) not more than 10% by weight of a unit from a conjugated diene, and (III) 30 to 90% by weight of a unit from an ethylenically unsaturated monomer other than the unsaturated nitrile and/or a unit resulting from the hydrogenation of a unit from a conjugated diene, said rubber being vulcanized with a sulfur vulcanization system.

Abstract: A process for catalytically hydrogenating a carbon-carbon double bond of a conjugated diene polymer by introducing hydrogen in the solution of said polymer, characterized in that a palladium salt of a carboxylic acid is used as a catalyst.