| 摘要 |
PURPOSE:To obtain the titled polymer having excellent initial adhesivity, peel strength and die-cutting property, and suitable as an adhesive, by polymerizing a vinyl aromatic compound and a conjugated diene successively under specific conditions, adding a mixture of both monomers to the reaction system, and polymerizing the monomers. CONSTITUTION:(A) A vinyl aromatic compound (preferably styrene) is polymerized in a hydrocarbon solvent using an organic lithium compound as an initiator. The amount of the component A is 2-30(wt)% of the whole monomer. After the completion of the polymerization reaction, (B) a conjugated diene (preferably isoprene) is polymerized. The amount of the component B is 30-48% of the whole monomer. After the polymerization of the component B, a monomer mixture consisting of 40-5% component A and 60-95% component B is added to the reaction system (the amount of the monomer mixture is 32-68% of the whole monomer), and polymerized to obtain a block copolymer of the vinyl aromatic compound and the conjugated diene wherein the content of the component A is 5-40%.
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