| 摘要 |
PROBLEM TO BE SOLVED: To provide a star block copolymer higher in molecular weight than the corresponding linear polymer and low in viscosity as well, having narrow dispersibility and high in the transmittance of the light with wavelengths close to 250 nm, and to provide a method for producing the block copolymer. SOLUTION: This star-shaped block copolymer has a central core and arm portions each consisting of a polymer chain extending from the central core; wherein the polymer chain has recurring unit of the general formula (I) (wherein, R1 is H or methyl; R2 is H or a 1-6C alkyl; p is 1 or 2; when p is 2, R2 may be the same or different), and the central core consists of a polymer block derived from a vinyl aromatic monomer or diene-based monomer and substantially contains no residual double bond. The other objective method for producing the star-shaped block copolymer is also provided.
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