POLYPROPYLENE, CRYSTALLINE COPOLYMERS OF PROPYLENE OR COMPOSITIONS OF POLYPROPYLENE AND OTHER POLYOLEFINES HAVING A HIGH IMPACT AND STRESS CRACK RESISTANCE

摘要

1. Polypropylene, crytalline copolymers or mixtures thereof with other polyolefins with a predominant proportion of polypropylene, of high impact strength and stress cracking resistance, characterized by a content of more than 65 %, measured by means of a differential scanning calorimeter, of crystallites having a hexagonal or pseudohexagonal crystal habit, a density of less than 0.905 g/cm3 according to DIN 53479 and by a content of 5 x 10**-4 to 5 x 10**-8 parts by mass of a mixed crystal of 5,12-dihydroquino (2,3-b) acridine-7,14-dione with quino (2,3-b) acridine-6,7,13,14(5H, 12H)-tetrone per 100 parts by mass of the total mixture, it also being possible for conventional stabilizers, light stabilizers and/of other conventional additives to be present.