| 摘要 |
FIELD: chemistry. ^ SUBSTANCE: invention relates to polyolefin compositions which have high decolouration and impact resistance. The composition contains from 50 to less than 70 wt % crystalline propylene homopolymer, 13-28 wt % elastomeric ethylene and propylene copolymer and 10-22 wt % polyethylene. Total amount of the elastomeric copolymer and polyethylene in the composition is more than 30 wt %. The crystalline propylene homopolymer has polydispersity index ranging from 4 to 10 and amount of isotactic pentades (mmmm) measured using 13C-NMR method on a fraction which is insoluble in xylene at 25C more than 97.5 mol %. The elastomeric ethylene copolymer is partially soluble in xylene at ambient temperature. The polymer fraction which is soluble in xylene has value of inherent viscosity, measured in tetrahydronaphthalene at 135C, which ranges from 2 to 4 dl/g. Polyethylene has inherent viscosity ranging from 1 to 3 dl/g. ^ EFFECT: obtained polypropylene compositions have relatively low hardness, high impact resistance and high resistance to decolouration, which enables their use in the motor car industry, particularly in bumpers and interior finishing, packaging and household objects. ^ 5 cl, 4 tbl, 6 ex |
