Disclosed are a diaphragm for a sound generating device and a sound generating device. The vibration diaphragm comprises at least one elastomer layer, wherein the elastomer layer is made of a hydrogenated nitrile butadiene rubber polymer; and the hydrogenated nitrile butadiene rubber polymer comprises acrylonitrile blocks, content of the acrylonitrile blocks in the hydrogenated nitrile butadiene rubber polymer ranging from 10 wt % to 70 wt %, a vulcanizing agent is added into the hydrogenated nitrile butadiene rubber polymer, and content of the vulcanizing agent is 1% to 15% of total content of the hydrogenated nitrile butadiene rubber polymer. The diaphragm of the present disclosure has excellent resilience, maintains high elasticity in a low-temperature environment and is capable of long-time working in a high-temperature environment, therefore enabling the sound generating device to be applied in an extremely severe environment while keeping its acoustic performance in an excellent state.

A roll covering includes a functional layer formed of a polymer which is a blend of at least one rubber and one millable polyurethane rubber. The polymer includes from 65% by weight to 85% by weight of the at least one rubber and from 15% by weight to 35% by weight of the millable polyurethane rubber. A roll having the roll core, a method of using the roll and a combination of the roll and a heated drying cylinder are also provided.

Provided is a positive electrode for a secondary battery that can cause a secondary battery to display excellent battery characteristics. The positive electrode for a secondary battery includes a positive electrode mixed material layer and a current collector. The positive electrode mixed material layer contains a positive electrode active material, a conductive material, a polymer A including a nitrogen-containing heterocycle and having a weight-average molecular weight of not less than 300 and not more than 70,000, and a polymer B including a nitrile group. The positive electrode mixed material layer has a degree of nitrogen segregation of 1.4 or less as determined using an electron probe microanalyzer.

Provided is a positive electrode for a secondary battery that can cause a secondary battery to display excellent battery characteristics. The positive electrode for a secondary battery includes a positive electrode mixed material layer and a current collector. The positive electrode mixed material layer contains a positive electrode active material, a conductive material, a polymer A including a nitrogen-containing heterocycle and having a weight-average molecular weight of not less than 300 and not more than 70,000, and a polymer B including a nitrile group. The positive electrode mixed material layer has a degree of nitrogen segregation of 1.4 or less as determined using an electron probe microanalyzer.

A gasket material, in which a crosslinked rubber layer compounding 30 to 200 parts by weight of titanium oxide based on 100 parts by weight of NBR or hydrogenated NBR is formed on a metal plate, improves blister resistance, and thus exhibits an excellent effect of preventing rubber peeling of the gasket in the engine and leading to an improvement of engine malfunction. Further, the use of NBR or hydrogenated NBR results in an advantage of low cost relative to that of fluororubber. Therefore, the gasket material of the present invention is effectively used as a cylinder head gasket.

A gasket material, in which a crosslinked rubber layer compounding 30 to 200 parts by weight of titanium oxide based on 100 parts by weight of NBR or hydrogenated NBR is formed on a metal plate, improves blister resistance, and thus exhibits an excellent effect of preventing rubber peeling of the gasket in the engine and leading to an improvement of engine malfunction. Further, the use of NBR or hydrogenated NBR results in an advantage of low cost relative to that of fluororubber. Therefore, the gasket material of the present invention is effectively used as a cylinder head gasket.

Disclosed is a gas seal member for high-pressure hydrogen device with sufficiently reduced occurrence of both swelling destruction and blister destruction. The gas seal member is formed of a cross-linked product of an elastomer composition which comprises an elastomer and fibrous carbon nanostructures, wherein a hydrogen diffusion coefficient D1 of a cross-linked product of an elastomer component including the elastomer and a hydrogen diffusion coefficient D2 of the cross-linked product of the elastomer composition satisfy the relationship 0.7<D2/D1<1.0.

Disclosed is a gas seal member for high-pressure hydrogen device with sufficiently reduced occurrence of both swelling destruction and blister destruction. The gas seal member is formed of a cross-linked product of an elastomer composition which comprises an elastomer and fibrous carbon nanostructures, wherein a hydrogen diffusion coefficient D1 of a cross-linked product of an elastomer component including the elastomer and a hydrogen diffusion coefficient D2 of the cross-linked product of the elastomer composition satisfy the relationship 0.7<D2/D1<1.0.

A nitrile group-containing copolymer rubber including 10 to 60 wt % of an α,β-ethylenically unsaturated nitrile monomer unit and 1 to 60 wt % of an α,β-ethylenically unsaturated dicarboxylic acid monoester monomer unit, and having an iodine value of 120 or less, wherein a processability index Ipro (Ipro=CC×SA) is 0.0030 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 and 1 to 60 wt % of an α,β-ethylenically unsaturated dicarboxylic acid monoester monomer unit, and having an iodine value of 120 or less, wherein a processability index Ipro (Ipro=CC×SA) is 0.0030 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.