| 摘要 |
A high impact polypropylene having an improved low brittleness temperature and an increased Izod impact strength is produced by blending together (1) a mixed copolymer, produced by first forming blocks of propylene homopolymer in presence of which there is then polymerized unreacted propylene and added ethylene by continuing the polymerization reaction thus resulting in said mixed copolymer with (2) a resinous radial block copolymer obtained by sequentially polymerizing a monovinyl-substituted aromatic hydrocarbon and a conjugated diene, and subsequently treating polymer thus obtained with a polyfunctional treating agent to obtain said copolymer which is radial with respect to long branches which radiate from a nucleus formed by the polyfunctional compound. The mixed copolymer can be produced by either batch or continuous operation. When produced by continuous operation, it is improved as a high-impact resin by addition of the radial copolymer, which lowers brittleness temperature and increases Izod impact. The batch produced mixed copolymer, the properties of which are already attractive can be further improved with respect to reduction of brittleness temperature and increase of Izod impact by adding thereto the radial resin. An increase in flexural modulus of the mixed copolymer, for example, as produced by continuous operation, can be obtained by blending it with polypropylene as produced by a usual method. Mixed copolymer is also blended with the radial copolymer and with polypropylene to obtain an improved high impact polypropylene polymer. The radial block copolymer can also be polymodal.
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