Abstract: A method for producing a polymer for oil-resistant rubber, which comprises adding, to an aqueous dispersion of an unsaturated nitrile-conjugated diene copolymer (component A), a monomer composition (component B) containing at least one kind of monomer selected from the group consisting of a nitrile group-containing monomer (component B-1), a (meth)acrylic acid ester monomer (component B-2) and an aromatic vinyl compound monomer (component B-3), and conducting a polymerization reaction in a state that the ratio of the conjugated diene monomer present in the system, to the total monomers present in the system is controlled at 10 mol % or less.

Abstract: The objective of the present invention is to provide an acrylic ester-based copolymer rubber which gives a rubber product excellent in fuel oil resistance and tensile strength and which is crosslinkable with sulfur and/or an organic peroxide and to provide a process for producing the same, as well as a rubber composition, an oil-resistant and weather-resistant rubber composition, and an oil-resistant and weather-resistant rubber product. The acrylic ester-based copolymer rubber of the present invention comprises a structural unit derived from at least one monomer selected from the group consisting of an acrylic acid alkyl ester and an acrylic acid alkoxyalkyl ester in an amount from 40 to 91.9% by mass, a structural unit derived from an unsaturated nitrile monomer in an amount from 8 to 40% by mass, and a structural unit derived from at least one monomer selected from the group consisting of a non-conjugated cyclic polyene and a compound having a specific structure in an amount from 0.

Abstract: A thermoplastic elastomer composition obtained by dynamically heat-treating a mixture containing a thermoplastic resin (A) having a melting point of not less than 200° C. and an elastomer (B) having a constitutional unit derived from an ester group-containing monomer in the presence of, as a crosslinking agent (C), a polymer (C-1) comprising a (meth)acrylate (c-1) unit having a weight average molecular weight (Mw) of 1,000 to 30,000 and a molecular weight distribution (Mw/Mn) of 1.0 to 4.0 and/or a polymer (C-2) which comprises 5 to 35 mass % of the (meth)acrylate (c-1) unit and 65 to 95 mass % of an aromatic vinyl monomer (c-2) unit, the polymer (C-2) having a weight average molecular weight (Mw) of 1,000 to 30,000 and a molecular weight distribution (Mw/Mn) of 1.0 to 4.0. The composition has a good sea-island structure as a whole and excellent heat resistance, and is useful as a substitute for acrylic rubbers.

Abstract: The objective of the present invention is to provide an acrylic ester-based copolymer rubber which gives a rubber product excellent in fuel oil resistance and tensile strength and which is crosslinkable with sulfur and/or an organic peroxide and to provide a process for producing the same, as well as a rubber composition, an oil-resistant and weather-resistant rubber composition, and an oil-resistant and weather-resistant rubber product. The acrylic ester-based copolymer rubber of the present invention comprises a structural unit derived from at least one monomer selected from the group consisting of an acrylic acid alkyl ester and an acrylic acid alkoxyalkyl ester in an amount from 40 to 91.9% by mass, a structural unit derived from an unsaturated nitrile monomer in an amount from 8 to 40% by mass, and a structural unit derived from at least one monomer selected from the group consisting of a non-conjugated cyclic polyene and a compound having a specific structure in an amount from 0.

Abstract: An object of the present invention is to provide an oil resistant and weather resistant rubber composition which leads to a molded product (rubber product) that has a sufficiently high strength and hardness, and low compression set, and that is excellent in ozone resistance; and a molded product such as a hose and a seal using the same. The oil resistant and weather resistant rubber composition of the present invention comprises an epoxy group-containing acrylic-based rubber having an epoxy group in an amount from 0.01 to 1.5 mmol/g, and a carboxyl group-containing unsaturated nitrile-conjugated diene-based copolymer having a carboxyl group in an amount from 0.02 to 2.5 mmol/g. The rubber composition may further comprise a reinforcing agent, a plasticizer, a crosslinking agent and the like.

Abstract: A thermoplastic elastomer composition having excellent heat aging characteristics, weather resistance, low-temperature physical properties, oil resistance and flexibility, and moldings using the same, such as hoses, are disclosed. The thermoplastic elastomer composition is obtained by dynamically heat treating a mixture containing (A) an olefin resin, (B) an unsaturated group-containing acrylic rubber, and (D) an inorganic filler in the presence of (E) a crosslinking agent, the component (B) comprising (B1) from 55 to 94.99% by weight of a structural unit derived from an acrylic acid alkyl ester monomer and/or an acrylic acid alkoxyalkyl ester monomer, (B2) from 0.

Abstract: A thermoplastic elastomer composition having excellent heat aging characteristics, weather resistance, low-temperature physical properties, oil resistance and flexibility, and moldings using the same, such as hoses, are disclosed. The thermoplastic elastomer composition is obtained by dynamically heat treating a mixture containing (A) an olefin resin, (B) an unsaturated group-containing acrylic rubber, and (D) an inorganic filler in the presence of (E) a crosslinking agent, the component (B) comprising (B1) from 55 to 94.99% by weight of a structural unit derived from an acrylic acid alkyl ester monomer and/or an acrylic acid alkoxyalkyl ester monomer, (B2) from 0.

Abstract: The present invention provides a conductive rubber composition with a low hardness and low distortion, and exhibiting less variations in volume specific resistance value and less dependence on environment, a manufacturing method thereof, and further, a conductive rubber member using the same. The conductive rubber composition of the present invention contains a particulate polymer (A1, crosslinked particulate polymer, and the like), an uncrosslinked polymer (A2), and a conductivity imparting agent (B). The particulate polymer (A1) is a nonpolar polymer (SBR, and the like), the uncrosslinked (A2) is a polar polymer (NBR, and the like), and the more conductivity imparting agent (B) exists in the uncrosslinked polymer than in the crosslinked particulate polymer. This composition can be obtained by starting the kneading of the above-described respective compounds at such a temperature (T C.) that the Mooney viscosity of the uncrosslinked polymer is equal or less than the Mooney viscosity of particulate polymer.

Abstract: An electrostatic image developing toner comprises a binder resin which contains at least 60% by weight of a styrene-butadiene copolymer. The copolymer contains a component A having a molecular weight of at least 100,000 in an amount of at least 20% by weight relative to the binder resin, and a component B having a molecular weight of at least 500,000 in the component A is not more than 15% by weight relative to the binder resin. The toner has adequate flowability and noncoagulation property and is capable of forming a superior visible image in a contact heat fixing system.

Abstract: A toner for developing an electrostatic latent image comprising a resin prepared by emulsion polymerization of a first polymer to yield a first emulsion, emulsion polymerization of a second polymer to yield a second emulsion, mixing said first and second emulsions and coagulating said mixture, wherein said second polymer has characteristics different from those of said first polymer.