Polypropylene compositions having improved impact strength properties at low temperatures and process for preparing same
US4521566A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 13, 1982 |
| Grant date | Jun 4, 1985 |
| Priority date | — |
| Expiry date | Oct 13, 2002 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L2308/00
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Polypropylene compositions having high impact strength at low temperatures comprising as essential components: PA1 100 parts by weight of polypropylene having an isotacticity index >90, PA1 8-25 parts by weight of an amorphous copolymeric fraction (1) of ethylene-propylene soluble in xylene at 23.degree. C., containing 20-80% by weight of ethylene, PA1 2-10 parts by weight of an ethylene-propylene crystalline copolymeric fraction (2) having a crystallinity of the polyethylene type containing 50-90% by weight of ethylene; and in which the weight ratio between the total polymerized ethylene and fraction (1) is <1. The compositions are prepared by polymerization processes comprising at least a step of homopolymerization of propylene to stereoregular polymer and a subsequent step of polymerization of ethylene-propylene mixtures in the presence of catalysts comprising a titanium compound carried on a magnesium halide in active form.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.