| abstract |
(57) [Summary] [Constitution] The total vinyl aromatic compound content is 20 to 50% by weight, the block content mainly of vinyl aromatic compounds is 5 to 30% by weight, and the ratio of the latter to the former is 0. ． A block copolymer of 2 to 0.8 of a vinyl aromatic compound and a conjugated diene, wherein the block mainly composed of the vinyl aromatic compound is composed of two or more blocks mainly composed of the vinyl aromatic compound, A block length ratio of the block chains is more than 0.9 and 1 or less, and the block mainly composed of the vinyl aromatic compound has a molecular weight of 0.1 to 10 000, which is excellent in low-temperature elongation and improved asphalt. Pledget. [Effect] An asphalt compound using a block copolymer having a specific structure as a modifier is excellent in low-temperature properties such as low-temperature elongation and is excellent in balance between excellent mechanical strength and processability. |