| 摘要 |
PURPOSE:To obtain the titled copolymer of high initial adherability, adherability retention, peel strength and die cuttability, by bonding, through specific coupling agent, vinyl aromatic compound block and a second block consisting mainly of conjugated diene. CONSTITUTION:(A) 10-100wt% of a vinyl aromatic compound (e.g., styrene) is subjected to anionic polymerization using, e.g., n-butyl lithium. Following the completion of the above polymerization, (B) the rest of either conjugated diene (e.g., isoprene) or a mixture of >=50wt% of said diene and <=50wt% of the component (A) is incorporated in the system to proceed with anionic polymer ization. On completion of this polymerization, (C) a tin-based coupling agent (e.g., SnCl4) and (D) a second coupling agent (e.g., dichloromethylsilane) is added to the system in a weight ratio (D)/(C) of 0-5, thus obtaining the objective copolymer having a constitution of formula (A and A' are each polymer block from the component (A), B is either polymer from the component (B) or copoly mer block from the components (A) and (B); X is residue of the component (C) or components (C) and (D); l is 2-4) with a component (A) content 3-70wt%.
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