Abrégé

Provided is a method for producing a carboxylated nitrile rubber, the method comprising a step in which a monomer mixture comprising an a,ß-ethylenically unsaturated nitrile monomer and a carboxylated monomer is polymerized in a solvent, a step in which a nitrous acid salt and a water-insoluble hydroquinone are added as polymerization terminators to the polymerization system to stop the polymerization, thereby obtaining a carboxylated-nitrile-rubber dispersion having a pH of 7 or lower, and a step in which the carboxylated-nitrile-rubber dispersion is coagulated to obtain a solid carboxylated nitrile rubber, the nitrous acid salt being used in an amount of 0.15 parts by weight or less per 100 parts by weight of the monomer mixture used in the polymerization.

Classes IPC  ?

• C08F 6/22 - Coagulation
• C08J 3/16 - Pulvérisation ou granulation par coagulation de dispersions

Abrégé

Provided is a latex of a carboxyl group-containing nitrile rUbbercontaining an a,P-ethylenically unsaturated nitrile monomer unit 01fl in a content of 8-60 wt% and a carboxyl group-containing MU, and having an iodine value of 120 or less, wherein the carboxyl group-containing MU is at least oneselected from an a,D-ethylenically unsaturated monocarboxylic acid MU, an a,D-ethylenically unsaturated polyvalent carboxylic acid MU, and an a,01,-ethylenically unsaturated dicarboxylic acid monoester MU, the total content of potassium and sodium in the latex is 2,300-10,000 ppm by weight, and the latex is obtained by hydrogenating a latex of a copolymer before hydrogenation whichis obtained by copolymerizing a mixture of an a43-ethylenically unsaturated nitrile monomer and a carboxyl group-containing monomer. Also provided are a mixture comprising the latex and a thermosetting resin, and a friction material prepared by making the mixture attached to or mixed with a base material.

Classes IPC  ?

• C08K 3/00 - Emploi de substances inorganiques en tant qu'adjuvants
• C08L 13/02 - Latex
• C08L 101/00 - Compositions contenant des composés macromoléculaires non spécifiés
• C09K 3/14 - Substances antidérapantesAbrasifs
• F16D 13/62 - Bandes d'embrayagesSabots d'embrayagesTambours d'embrayages
• F16D 69/02 - Composition des garnitures

Abrégé

A nitrile rubber composition comprising a highly saturated nitrile rubber (A) containing .alpha.,.beta.-ethylenically unsaturated nitrile monomer units in a ratio of 8 to 60 wt% and having an iodine value of 120 or less and an alkylated phenol compound (B), wherein a ratio of content of the alkylated phenol compound (B) with respect to a total of the highly saturated nitrile rubber (A) and the alkylated phenol compound (B) is 0.01 to 1 wt%, and a difference (.eta.2-.eta.1) between a plasticity number n2 after storage at 70.degree.C for 7 days in a state of an aqueous dispersion by being dispersed in water and a plasticity number .eta.1 before the storage is 12 or less is provided.

Classes IPC  ?

• C08K 5/13 - PhénolsPhénolates
• C08K 7/02 - Fibres ou "whiskers"
• C08L 9/02 - Copolymères avec l'acrylonitrile

Abrégé

A nitrile group-containing copolymer rubber containing .alpha., .beta.-ethylenically unsaturated nitrile mononer units in a ratio of 10 to 60 wt% and having a Z-average radius of gyration of 100 nm or more is provided. Preferably, the nitrile group-containing copolymer rubber of the present invention has an iodine value of 120 or less. Further, preferably, the nitrile group-containing copolymer rubber of the present invention has a plasticity number of 14 to 90. According to the present invention, it is possible to provide a nitrile group-containing copolymer rubber able to give a cross-linked rubber excellent in tensile stress, compression set resistance, and low heat buildup property.

Classes IPC  ?

• C08F 236/12 - Copolymères de composés contenant plusieurs radicaux aliphatiques non saturés et l'un au moins contenant plusieurs liaisons doubles carbone-carbone le radical ne contenant que deux doubles liaisons carbone-carbone conjuguées avec des nitriles
• C08L 9/02 - Copolymères avec l'acrylonitrile

Abrégé

A nitrile group-containing copolymer rubber which has a hydroxyl group, carboxyl group, or carbon-carbon double bond at an end carbon atom or on a carbon atom which bonds with the end carbon atom is provided. The nitrile group-containing copolymer rubber of the present invention is preferably obtained by a metathesis reaction. According to the present invention, a nitrile group-containing copolymer rubber which is excellent in cross-linkability can be provided.

Classes IPC  ?

• C08C 19/00 - Modification chimique du caoutchouc
• C08L 9/02 - Copolymères avec l'acrylonitrile