Hydrogenated block copolymer and polypropylene resin composition containing the same

Abstract

A hydrogenated block copolymer comprising: two polymer blocks A mainly comprising vinylaromatic hydrocarbon compound monomer units; and one hydrogenated polymer block B mainly comprising butadiene monomer units, in which at least 90% of olefinically unsaturated double bonds contained in a polymer block mainly comprising butadiene monomer units before hydrogenation have been hydrogenated, wherein a bonding vinylaromatic hydrocarbon compound content in the hydrogenated block copolymer is higher than 13 wt % but lower than 25 wt %, a 1,2-bond content in the unhydrogenated polymer block mainly comprising butadiene monomer units is higher than 40 mol % but lower than 60 mol %, and the copolymer has a quantity of heat of crystal fusion (ΔH) smaller than 0.05 J/g, an order-disorder transition temperature of 200° C. or higher, and a melt flow rate (MFR) value, as determined in accordance with JIS K7210 under the conditions of a temperature of 230° C. and a load of 2.16 kg, of from not smaller than 0.1 g/10 min to smaller than 30 g/10 min. By incorporating the copolymer into a polypropylene resin, a composition which is suitable for giving a molded article having an excellent balance among impact resistance, brittle temperature, rigidity, heat distortion resistance, and tensile elongation at break, can be obtained.

Dependencies are inferred from the claim text.