| 摘要 |
PROBLEM TO BE SOLVED: To obtain a selectively partially hydrogenated branched conjugated diene polymer for an impact resistant vinyl aromatic resin excellent in bale characteristic, glossiness, impact resistance and thermal stability.SOLUTION: A selectively partially hydrogenated branched conjugated diene polymer satisfies (1) to (6) below. (1) A content of a branched component is 70-95 mass%. (2) There are two or more peaks in a GPC molecular weight distribution curve, with a polystyrene equivalent peak molecular weight (A) in a portion with the lowest molecular weight (non-branched component) being 50,000-150,000, of which a ratio to the polystyrene equivalent molecular weight (B) in the highest peak on a side of a higher molecular weight (branched component) than the portion with the lowest molecular weight (non-branched component) (B/A) being 2.5-3.5. (3) A content of a vinyl bonding portion derived from a double bond of the conjugated diene polymer is 10-30%. (4) A hydrogenation rate of the double bond of the conjugated diene polymer is 10-40%. (5) A hydrogenation rate in the vinyl bonding portion is 80-99.0%. (6) A 5% SV at 25°C is 20-50 (cP). |
