# US 5,344,885 A · Preparation of propylene-ethylene copolymers

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- Number: US 5,344,885 A
- Document ID: US5344885A
- Status: Granted
- Kind: A
- Application number: 08/022,086
- Filed: 1993-02-25
- Granted: 1994-09-06
- Earliest claimed: 1992-02-29
- Assignees: BASF SE
- Inventors: Meinolf Kersting; Juergen Kerth; Klaus-Dieter Hungenberg; Patrik Mueller; Peter Koelle
- Web page: https://patentgrep.com/patent/US5344885A

## CPC

- C08F 297/083: {the monomers being ethylene or propylene}
- C08F 210/16: Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS

## Abstract

Propylene-ethylene copolymers are obtained by two-stage polymerization from the gaseous phase in an agitated fixed bed by means of a Ziegler-Natta catalyst system that contains in addition to a titanium-containing solid component also an aluminum compound as co-catalyst, wherein as Ziegler-Natta catalyst system a system is used which, following the reaction of the titanium-containing solid component with the co-catalyst, is deactivated by reaction with carbon dioxide. The copolymers are used for producing fibers, films and moldings.

## Claims

### Claim 1

A process for preparing a propylene-ethylene copolymer using a Ziegler-Natta catalyst system that contains a titanium-containing solid component and an aluminum compound as co-catalyst wherein the titanium-containing solid component is preactivated by reaction with the co-catalyst followed by deactivation of the preactivated catalyst system by reaction with carbon dioxide further followed by reactivation of the catalyst system by addition of the co-catalyst for effecting polymerization from the gaseous phase in an agitated fixed bed.

### Claim 2 (depends on 1)

A propylene-ethylene copolymer obtained by a process as claimed in claim 1.

### Claim 3 (depends on 2)

A method of using a propylene-ethylene copolymer as claimed in claim 2 for producing fibers, films and moldings.

### Claim 4 (depends on 2)

Fibers, films and moldings produced from a propylene-ethylene copolymer as claimed in claim 2 as essential component.