Method for preparing block copolymers of propylene
US5175208A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 10, 1989 |
| Grant date | Dec 29, 1992 |
| Priority date | — |
| Expiry date | Jul 10, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F297/083
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
An improved method for preparing block copolymers of propylene which comprises providing a polymerizer composed of at least two reaction vessels connected to one another, substantially homopolymerizing propylene in a first step and then copolymerizing ethylene and propylene in a second step in the presence of a stereoregular catalyst, characterized by carrying out the homopolymerization of propylene in the polymerizer composed of at least two reaction vessels connected to one another in series, then introducing the resulting polymer slurry into a countercurrent washing column and countercurrently washing the slurry with propylene, introducing the washed slurry withdrawn from the lower part of the washing column into a reaction vessel in the second step connected to the washing column and performing the polymerization of ethylene and propylene, of which ratio ranges from 15/85 to 95/5. According to this method, a block copolymer of propylene exhibiting excellent physical properties can be obtained efficiently.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.