Patent ID: 7592381
Filing Date: 2009-09-22
Classification: C08F,C08L

Abstract:
1. A process for preparing a polymer modified bituminous binder composition in the substantial absence of crosslinking agents, said process comprising the steps of: a. heating a bitumen component in a stirred tank to a temperature from 185° C. to 221° C.; b. adding a block copolymer composition to the bitumen component while the bitumen component is being stirred to form a homogeneous mixture of the bitumen component and the block copolymer composition; and c. continuing to stir the homogeneous mixture while maintaining the temperature from 185° C. to 221° C. for a period of time from 4 hours to 30 hours thereby forming a cured polymer modified bituminous binder composition; wherein said block copolymer composition comprises wherein when both (i) and (ii) are present in the block copolymer composition, the ratio of (i) to (ii) is greater than 1:1, and wherein the melt index for the block copolymer composition is from about 20 g/10 min to about 35 g/10 min as determined by ASTM D 1238, condition G (200° C., 5 kg load).