Patent ID: 11608404

Abstract:
Disclosed herein are linear block copolymers of formula A-B-A′ or A-B*B-A′, wherein blocks A and A′ are polystyrene blocks, block B is a poly(conjugated diene) block and * is a coupling agent having a vinyl content of from 10-60 mol %. The block copolymers have a polystyrene content of from 20-35 wt. %, relative to the overall weight of the block copolymer, and a molecular weight of from 200,000-300,000 g/mol. The block copolymers can be used with a wide variety of asphalt grades, and are valuable for producing homogeneous polymer modified asphalt compositions having an effective combination of performance properties, such as acceptable viscosity, good elastic response to an applied stress, and a low non-recoverable creep compliance. The combination of vinyl content and polymerization technology allows a high solution concentration during polymerization without excessive processing viscosity.