Elastomeric copolymers of ethylene and propylene and their production and use

Claim 2

Elastomeric copolymers of ethylene and propylene containing by weight from 34 to 67% of units derived from ethylene and from 33 to 66% by weight of units derived from propylene, at least 60% of the units derived from propylene being disposed in sequences of at least three successive units, and theirfusion enthalpy, as measured after a given heat treatment being lowerthan 15 callg.

Claim 3

Copolymers as claimed in claim 1, in which the said fusion enthalpy is from 5to 10 cal/g.

Claim 4

Copolymers as claimed in claim 1 or2 contain ing by weight from 45 to 60% of units derived from ethylene and 40to45%of units derived from prop ylene. 4. A process for the production of the copolym- 40 ers claimed in claim 1, comprising copolymerising ethylene and propylene in the presence of a catalytic system comprising one or more compounds of titanium and one or more organo-metallic com pounds of one or more metals of group 11 andlor Ill of 45 the Periodic Table of elements, the catalytic system being capable of polymerising ethylene and prop Viene at similar speeds.

Claim 5

4

Claim 6

4

Claim 7

A process as claimed in claim 4 in which the titanium compounds are produced by the reduction of titanium tetrachloride by means of an organoaluminium compound at a temperature in the range -10 to WC and then heating the resulting precipi- tate for a period of some minutes to some hours at a temperature not exceeding 15WC, this reduction being carried out in the presence of an electron donor or followed by treatment with an electron donor; and the organo-metallic compounds of a metal of group 11 or Ill are organo-aluminium compounds having the mean formula A1 RJ(,x), where R represents a C2-12 alky[ group, Z represents a hydrogen or halogen atom and x represents an integer or a fraction of any value from 1 to 3.

Claim 8

A process as claimed in claim 5 in which the electron donor is an aliphatic ether having the formula WOR- where each of Wand W'S a C2-5 alkyl group.

Claim 9

A process as claimed in anyone of claims 4to 6 in which the ratio between the concentrations of ethylene and of propylene in the polymerisation medium is maintained constant throughout the polymerisation operation. n 7

Claim 10

A process as claimed in anyone of claims 4to 7 in which copolymerisation of ethylene and propylene is effected by bringing the monomers in the gaseous state into contact with solid particles of the copolymer in the course of formation and with the components of the catalytic system, optionally in association with a solid granular carrier orwith a pre-polymer.

Claim 11

A process as claimed in claim 4, carried out substantially as hereinbefore described in any one of the Examples.

Claim 12

Copolymers obtained by a process as claimed in any one of claims 4 to 9.

Claim 13

Copolymers as claimed in claim 1 for use in the production of isotactic polypropylene compositions having both an elevated impact strength at temperatures below 250C and good resistance to deformation under load at temperatures above 90T. Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd., Berwick-upon-Tweed, 1981. Published at the Patent Office, 25Southampton Buildings, London, WC2A 'I AY, from which copies may be obtained. GB 2 053 246 A 7