Zeon Corporation

Kiyonori Umetsu

Hiroyasu Nagamori

Yoshiaki Aimura

Shigeru Fujita

Akira Tsukada

Isao Kubota

Hirofumi Masuda

Masao Nakamura

Masaaki Komatsu

Takeshi Karato

Takahiko Fukahori

Kouji Shouya

Disclosed herein are a nitrile rubber composition comprising a nitrile rubber (a) including an &#x3b1;,&#x3b2;-ethylenically unsaturated nitrile monomer unit and having iodine value of 100 or less, an &#x3b1;,&#x3b2;-ethylenically unsaturated carboxylic acid metallic salt (b), and silane-treated fumed silica and/or calcinated wet silica (c); a cross-linkable nitrile rubber composition comprising the above nitrile rubber composition and a crosslinking agent (d); and a cross-linked rubber obtained by crosslinking the cross-linkable nitrile rubber composition. The present invention can provide a nitrile rubber composition and a cross-linkable nitrile rubber composition, capable of giving a highly-saturated cross-linked nitrile rubber having high tensile stress and excellent heat resistance, and a cross-linked rubber thereof.

Nitrile rubber composition, cross-linkable nitrile rubber composition and cross-linked rubber

A crosslinkable rubber composition comprising 0.2 to 10 parts by weight of an aromatic secondary amine-based anti-aging agent and 0.5 to 20 parts by weight of a polyamine-based crosslinking agent with respect to 100 parts by weight of a nitrile rubber including an &#x3b1;,&#x3b2;-ethylenically unsaturated nitrile unit and an &#x3b1;,&#x3b2;-ethylenically unsaturated dicarboxylic acid monoester unit, and with iodine value of 120 or less. The present invention can provide a crosslinkable rubber composition, providable of a cross-linked rubber excellent in a variety of properties such as mechanical strength and small in compression set, and a cross-linked rubber obtained by cross-linking the rubber composition.

Crosslinkable rubber composition and cross-linked rubber

An acrylic rubber comprised of a copolymer comprising 0.1 to 20% by weight of (A) units of a butenedioic acid monoester monomer having an alicyclic structure and 50 to 99.9% by weight of (B) units of at least one kind of monomer selected from acrylic acid ester monomers and methacrylic acid ester monomers. A crosslinkable acrylic rubber composition comprising the acrylic rubber and a crosslinking agent, especially a polyamine crosslinking agent, has good process-stability and good shapability and gives a shaped article having high heat resistance and exhibiting reduced permanent set.

Shaped article composed of an acrylic rubber composition

An acrylic rubber composition comprising (A) 100 weight parts of an acrylic rubber comprising 80-99.9 weight % of units of a monomer selected from acrylic acid ester monomers and methacrylic acid ester monomers, and 0.1-20 weight % of units of an &#x3b1;,&#x3b2;-ethylenically unsaturated carboxylic acid monomer, (B) 5-200 weight parts of synthetic silica, and (C) 0.05-20 weight parts of a crosslinking agent. The acrylic rubber composition preferably further comprises 5-200 weight parts of aluminum silicate containing at least 5 weight % of AlOwherein the total amount of AlOand SiOis at least 60 weight %. The rubber composition has good storage stability and gives a crosslinked object having good heat aging resistance, reduced compression set and good mechanical properties.

Acrylic rubber composition and crosslinked object

A conjugated diene rubber obtained by a process wherein active conjugated diene polymer chains each having an active metal at a polymer chain terminal, which have been obtained by polymerizing a conjugated diene monomer alone, or a conjugated diene monomer and an aromatic vinyl monomer with the aid of an organic active metal in an inert solvent, are allowed to react with a specific polyorganosiloxane capable of reacting with the active metal bonded to the polymer chain terminal. The conjugated diene rubber contains at least 5% by weight of a structure comprising at least three conjugated diene polymer chains bonded through a polyorganosiloxane. The conjugated diene rubber gives, when silica is incorporated therein, a rubber composition having good processability and giving a crosslinked rubber having reduced heat build-up, good wet grip performance and good abrasion resistance.

Conjugated diene rubber, process for producing the same, and rubber composition

An acrylic rubber composition comprising a carboxyl group-containing acrylic rubber (A) comprising 0.1 to 30% by weight of structural units derived from methacrylonitrile, and a polyamine crosslinking agent (B) and a monoamine compound (C); wherein the amount of each of the crosslinking agents (B) and the monoamine compound (C) is in the range of 0.05 to 20 parts by weight based on 100 parts by weight of the acrylic rubber (A). This acrylic rubber composition is free from sticking to a metal at kneading and exhibits good resistance to scorch during being processed, and gives a crosslinked product having good heat resistance, good cold resistance and good resistance to deteriorated oil.

Acrylic rubber composition and crosslinked product

A vulcanizable acrylic rubber composition comprising (A) 100 weight parts of an acrylic rubber comprising units of an acrylic acid ester monomer (a) and units of a carboxyl group-containing ethylenically unsaturated monomer (b), (B) 0.05&#x2013;5 weight parts of a primary polyamine vulcanizer, and (C) 0.5&#x2013;5.5 weight parts of at least one aliphatic monoamine compound selected from aliphatic secondary monoamine compounds (C-1) and aliphatic tertiary monoamine compounds (C-2); wherein the sum in amount of the monomer (a) units plus the monomer (b) units in the acrylic rubber (A) is at least 80% by weight based on the total monomer units, and the ratio in amount of the monomer (a) units to the sum of the monomer (a) units plus the monomer (b) units is 90&#x2013;99.9 weight %. This vulcanizable acrylic rubber composition is not liable to easily stick to a metal surface and has good scorch resistance, and gives a vulcanizate having good oil resistance and metal corrosion resistance.

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Tokyo, Japan

Kiyonori Umetsu