The vinylidene-fluoride-based polymer composition according to the present invention comprises a vinylidene-fluoride-based polymer and a specific surfactant and contains no fluorinated surfactant, wherein the specific surfactant is contained in an amount of 10 ppm or larger but less than 100 ppm in terms of mass ppm of the solid components of the composition and has an HLB value of 10 or greater. The method for producing a vinylidene-fluoride-based polymer according to the present invention comprises emulsion-polymerizing specific monomers in an aqueous medium in the presence of a specific emulsifier and an initiator without using any fluorinated surfactant, the use amount of the emulsifier being 8.5 ppm or larger but less than 100 ppm in terms of mass ppm of the monomers.

An acrylic rubber composition that includes a blend product of an acrylic rubber [I] containing a copolymer of an ethyl acrylate/n-butyl acrylate/2-methoxyethyl acrylate/carboxyl group-containing vinyl monomer, and an acrylic rubber [II] containing a copolymer of an alkoxyalkyl acrylate/2-ethylhexyl acrylate/alkyl methacrylate/ethyl acrylate/carboxyl group-containing vinyl monomer; the blend product being compounded with silica and a plasticizer.

An acrylic rubber composition that includes a blend product of an acrylic rubber [I] containing a copolymer of an ethyl acrylate/n-butyl acrylate/2-methoxyethyl acrylate/carboxyl group-containing vinyl monomer, and an acrylic rubber [II] containing a copolymer of an alkoxyalkyl acrylate/2-ethylhexyl acrylate/alkyl methacrylate/ethyl acrylate/carboxyl group-containing vinyl monomer; the blend product being compounded with silica and a plasticizer.

Provided are a UV-curable non-isocyanate polyurea polymer and a UV-curable coating composition containing the same. The UV-curable non-isocyanate polyurea polymer has one or more ethylenically unsaturated functional groups and the ethylenically unsaturated functional groups are attached to nitrogen atoms present in a backbone urea segment via —C(=0)- linkage. The nonisocyanate polyurea polymer is prepared by: (i) providing an ethylenically unsaturated compound having one or more carboxylic acid functional groups; and (ii) reacting said ethylenically unsaturated compound having one or more carboxylic acid functional groups with a multi-carbodiimide polymer to form the non-isocyanate polyurea polymer.

A nitrile group-containing copolymer rubber including 10 to 60 wt % of an α,β-ethylenically unsaturated nitrile monomer unit a nd 1 to 60 wt % of an α,β-ethylenically unsaturated dicarboxylic a cid monoester monomer unit, and having an iodine value of 120 or 1 ess, wherein a processability index Ipro (Ipro=CC×SA) is 0.003 0 or less, where the processability index Ipro is the product of the carboxyl group content CC, which is the number of moles of carboxyl groups per 100 g of nitrile group-containing copolymer rubber, and the absorbance area SA of a carboxylic anhydride group determined by infrared spectroscopy.

A nitrile group-containing copolymer rubber including 10 to 60 wt % of an α,β-ethylenically unsaturated nitrile monomer unit a nd 1 to 60 wt % of an α,β-ethylenically unsaturated dicarboxylic a cid monoester monomer unit, and having an iodine value of 120 or 1 ess, wherein a processability index Ipro (Ipro=CC×SA) is 0.003 0 or less, where the processability index Ipro is the product of the carboxyl group content CC, which is the number of moles of carboxyl groups per 100 g of nitrile group-containing copolymer rubber, and the absorbance area SA of a carboxylic anhydride group determined by infrared spectroscopy.

An aspect of the present invention is an acrylic rubber containing only an alkyl acrylate, ethylene and a crosslinking monomer as monomer units, wherein a content of a polyvinyl alcohol in the acrylic rubber is 0.5 to 2% by mass.

An aspect of the present invention is an acrylic rubber containing only an alkyl acrylate, ethylene and a crosslinking monomer as monomer units, wherein a content of a polyvinyl alcohol in the acrylic rubber is 0.5 to 2% by mass.

A method for producing an acrylic rubber, the method including dividedly adding 80% to 100% by mass of the total mass of a monomer component containing 100 parts by mass of an acrylic acid alkyl ester having an alkyl group having 1 to 3 carbon atoms, 20 to 160 parts by mass of an acrylic acid alkyl ester having an alkyl group having 4 to 8 carbon atoms, and 0.1 to 10 parts by mass of a crosslinking seat monomer containing a carboxyl group, and performing emulsion polymerization at a polymerization temperature of 20° C. to 60° C. The monomer component may further contain a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms, and ethylene.

A method for producing an acrylic rubber, the method including dividedly adding 80% to 100% by mass of the total mass of a monomer component containing 100 parts by mass of an acrylic acid alkyl ester having an alkyl group having 1 to 3 carbon atoms, 20 to 160 parts by mass of an acrylic acid alkyl ester having an alkyl group having 4 to 8 carbon atoms, and 0.1 to 10 parts by mass of a crosslinking seat monomer containing a carboxyl group, and performing emulsion polymerization at a polymerization temperature of 20° C. to 60° C. The monomer component may further contain a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms, and ethylene.