Zeon Corporation

Ryoji Oda

Daisuke Kato

Sadaharu Hashimoto

Yuta Ishii

Leo Tsunoi

The present disclosure provides a block copolymer composition for a flexographic plate comprising a block copolymer A represented by the following general formula (A) and a block copolymer B represented by the following general formula (B), wherein: a content of aromatic vinyl monomer units relative to all monomer units constituting polymer components of the block copolymer composition for the flexographic plate is 18% to 70% by mass; a type A hardness is 25 to 65; and an anisotropic index is 2.0 or less.

Block copolymer composition for flexographic plate

A tetrablock copolymer having an aromatic vinyl block (A1), a conjugated diene block (B1), an aromatic vinyl block (A2), and a conjugated diene block (B2) is provided, wherein Mw(A2)/Mw(A1) is 1.2 to 5, Mw(A2) is 12,000 or more, Mw(B1)&#x3e;Mw(B2), Mw(Total) is 50,000 to 400,000 where the weight average molecular weight of the aromatic vinyl block (A1) is defined as Mw(A1), the weight average molecular weight of the conjugated diene block (B1) is defined as Mw(B1), the weight average molecular weight of the aromatic vinyl block (A2) is defined as Mw(A2), the weight average molecular weight of the conjugated diene block (B2) is defined as Mw(B2), and the weight average molecular weight of the tetrablock copolymer as a whole is defined as Mw(Total), and the content of aromatic vinyl monomer units is 10 to 30% by weight.

Tetra-block copolymer, and polymer composition, and hot-melt sticky adhesive composition using these

The present invention provides a block copolymer composition comprising a block copolymer A represented by formula (A) and a block copolymer B represented by formula (B), the block copolymer composition having a water content of 200 ppm by weight or less when the block copolymer composition has been formed in a shape of pellets, dried, and allowed to stand at a temperature of 37&#xb0; C. and a relative humidity of 70% for 24 hours. In the formulas, Ar1, Ar1, and Ar2are aromatic vinyl polymer blocks having a weight average molecular weight of 6,000-18,000, Ar2is an aromatic vinyl polymer block having a weight average molecular weight of 40,000-400,000, and Dand Dare specific conjugated diene polymer blocks. The block copolymer composition has a high modulus of elasticity, exhibits low tension set, and ensures that the formation of a hole is prevented when a film is formed by melt-forming the block copolymer composition.Ar1-D-Ar2&#x2003;&#x2003;(A)Ar1-D-Ar2&#x2003;&#x2003;(B)

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Tokyo, Japan

Ryoji Oda