| 摘要 |
The present invention provides a composition which comprises a radial poly(aromatic vinyl)/polyisoprene block copolymer as a major component and which can be used as a more excellent pressure-sensitive ingredient. This composition is obtained by reacting a diblock polymer with a coupling agent having a functionality of 4 or higher in the presence of a coupling accelerator, and it contains (a) 1 to 34% by weight of a diblock polymer, (b) 34 to 99% by weight of a four-branch polymer, and (c) 0 to 50% by weight of a two-branch polymer and/or a three-branch polymer. The poly(aromatic vinyl)/polyisoprene block copolymer contained in the composition has a weight-average molecular weight (Mw) of 260,000 to 500,000, and the poly(aromatic vinyl)/polyisoprene block copolymer has a poly(aromatic vinyl) block content of 5 to 24% by weight.
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