| 摘要 |
<p>A block copolymer composed of an aromatic vinyl compound polymer block, a butadiene polymer block and an isoprene polymer block. It has the weight-average molecular weight of 10,000 to 500,000, the content of the bonded aromatic vinyl compound of 10-50 wt.%, the content of the bonded butadiene of 10-60 wt.%, the content of the bonded isoprene of 10-60 wt.%, the content of the 1,2-vinyl bonds in the butadiene portion of 15 % or less, the content of the 3,4-vinyl bonds in the isoprene portion of 10 % or less, the storage modulus of 106-3x108 Pa according to viscoelasticity measurement in the temperature range of 0 to 50 °C, only one peak of the loss tangent due to the butadiene and isoprene polymer blocks in the temperature range of -80 to -50 °C, and a reduced change in the melt viscosity with time. The invention also provides a pressure-sensitive adhesive composition comprising the above copolymer and a tackifier.</p> |
