Abstract: An object of the present invention is to provide a block copolymer composition containing an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer, which is capable of achieving a high-level balance between a high elastic modulus and a small permanent set, and is capable of producing a highly isotropic molded product having uniform mechanical properties even when a molding method which is likely to cause molecular orientation, such as extrusion molding, is applied.

Abstract: A block copolymer composition comprising an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer having a high-level balance between a high elastic modulus and a small elongation set is provided. The block copolymer composition comprises a block copolymer A represented by formula (A) and a block copolymer B represented by formula (B), where the weight ratio of the block copolymer A to the block copolymer B, A/B, is from 36/64 to 85/15 and the ratio of the aromatic vinyl monomer units relative to all polymer components in the block copolymer composition is 27-70 wt %. Ar1a-Da-Ar2a (A). Ar1b-Db-Ar2b (B).

Abstract: Provided is a composition for a stretchable film, which achieves a high-level balance between a high elastic modulus and a small permanent set, and can be formed into a stretchable film with satisfactory formability. A composition for a stretchable film comprises a block copolymer composition containing a block copolymer A represented by the following general formula (A) and a block copolymer B represented by the following general formula (B), and a tackifier resin: Ar1a-Da-Ar2a ??(A) (Arb-Db)n-X ??(B), in the general formulas (A) and (B), Ar1a and Arb each represent an aromatic vinyl polymer block having a weight average molecular weight of 6,000 to 20,000; Ar2a represents an aromatic vinyl polymer block having a weight average molecular weight of 40,000 to 400,000; Da and Db each represent a conjugated diene polymer block having a vinyl bond content of 1 mol % to 20 mol %; X represents a single bond or a residue of a coupling agent; and n represents an integer of 2 or greater.

Abstract: Provided is a composition for a stretchable film, which achieves a high-level balance between a high elastic modulus and a small permanent set, and can be formed into a stretchable film with satisfactory formability. A composition for a stretchable film comprises a block copolymer composition containing a block copolymer A represented by the following general formula (A) and a block copolymer B represented by the following general formula (B), and a tackifier resin: Ar1a-Da-Ar2a ??(A) (Arb-Db)n-X ??(B), in the general formulas (A) and (B), Ar1a and Arb each represent an aromatic vinyl polymer block having a weight average molecular weight of 6,000 to 20,000; Ar2a represents an aromatic vinyl polymer block having a weight average molecular weight of 40,000 to 400,000; Da and Db each represent a conjugated diene polymer block having a vinyl bond content of 1 mol % to 20 mol %; X represents a single bond or a residue of a coupling agent; and n represents an integer of 2 or greater.

Abstract: An object of the present invention is to provide a block copolymer composition containing an aromatic vinyl-conjugated diene-aromatic vinyl block copolymer, which is capable of achieving a high-level balance between a high elastic modulus and a small permanent set, and is capable of producing a highly isotropic molded product having uniform mechanical properties even when a molding method which is likely to cause molecular orientation, such as extrusion molding, is applied.

Abstract: A rubber covered roll of a structure that a rubber layer is formed on the surface of a roll-like base is provided. The rubber layer is a layer formed of a vulcanizate of a rubber composition comprising 25-95 wt. % of copolymer rubber (A) obtained by copolymerizing 28-70 mol % of an alkylene oxide, 28-70 mol % of an epihalohydrin and 2-15 mol % of an ethylenically unsaturated epoxide, and 5-75 wt. % of unsaturated rubber (B). The rubber covered roll does not contaminate any photosensitive member, stably has a low electric resistance, and is low in dependence of electric resistance on environment and in hardness. An image-forming apparatus equipped with the rubber covered roll as a development roll or charging roll, and a rubber composition for the rubber covered roll are also provided.