Patent ID: 8580874

Claim:
A process for preparing a modified asphalt composition, the process comprising: introducing a molten asphalt composition; introducing from about 0.1 to about 10 parts by weight, per 100 parts by weight of the modified asphalt composition, of a polymeric blend including a star-branched diene end-capped block copolymer and a linear diene end-capped block copolymer into the molten asphalt composition, where the star-branched block copolymer is defined by the formula α-(D-V-d) x where each D is independently a polydiene block, each V is independently a vinyl aromatic block, each d is a polydiene end cap, α is a coupling moiety that couples at least three chains of a living polymer defined by formula d-V-D ⊖ , and x is an integer from 3 to 10, and where the linear block copolymer is defined by the formula (D-V-d) where each D is independently a polydiene block, each V is independently a vinyl aromatic block, each d is a polydiene end cap, where the ratio of star-branched diene end-capped block copolymer to linear diene end-capped block copolymer is at least 0.5:1 and less than 9.5:1.