Atactic copolymers of propylene with ethylene

Claim 2

The copolymer according to claim 1, wherein the syndiotactic diads (r) are more numerous than the isotactic diads (m).

Claim 3

The copolymer according to one of claims 1 or 2, wherein the percentage molar content of ethylene in the copolymer (%E) and the ratio PEP/(PEP+PEE+EEE) satisfy the following relationship: 0.012%E + PEP/(PEP+PEE+EEE) ≧ 1

Claim 4

The copolymer according to one of claims 1 to 3, having a Cluster Index C.I.(E) value lower than 0.7.

Claim 5

The copolymer according to one of claims 1 to 4, having a value of intrinsic viscosity (I.V.) greater than 0.5 dl/g.

Claim 6

The copolymer according to one of claims 1 to 5, having a value of the ratio M w /M n lower than 4.

Claim 7

A process for the preparation of a copolymer of propylene as claimed in one of claims 1 to 6, comprising the reaction of polymerization of mixtures of propylene and ethylene in the presence of a catalyst comprising the product of the reaction between: (A) a metallocene compound of formula (I): in which the substituents R 1 , which may be identical or different, are hydrogen atoms, C 1 -C 20 alkyl radicals, C 3 -C 20 cycloalkyl radicals, C 2 -C 20 alkenyl radicals, C 6 -C 20 aryl radicals, C 7 -C 20 alkaryl radicals or C 7 -C 20 aralkyl radicals, possibly two adjacent substituents R 1 can form a ring comprising from 5 to 8 carbon atoms, and furthermore the substituents R 1 can contain atoms of Si or Ge; the R 2 bridging group is selected from >CR 1 2 , >SiR 1 2 , >GeR 1 2 , >NR 1 or >PR 1 , where R 1 is defined as above and possibly, when R 2 is >CR 1 2 , >SiR 1 2 or >GeR 1 2 , the two substituents R 1 can form a ring comprised of 3 to 8 atoms; M is an atom of a transition metal selected from among those belonging to group 3, 4, 5, or to the lanthanides group or the actinides group in the Periodic Table of the Elements (new IUPAC version); the substituents X, which may be identical or different, are halogen atoms, -OH, -SH, R 1 , -OR 1 , -SR 1 , -NR 1 2 or -PR 1 2 , where R 1 is defined as above; possibly as the product of reaction with an organometallic compound of aluminium of formula AlR 4 3 or Al 2 R 4 6 , in which the substituents R 4 , which may be identical or different, are R 1 or halogen, and (B) an aluminoxane, if necessary mixed with an organometallic compound of aluminium of formula AlR 4 3 or Al 2 R 4 6 , in which the substituents R 4 , which may be identical or different, are defined as above, or one or more compounds capable of forming a cationic alkyl metallocene.

Claim 8

The process according to claim 7, wherein the substituents R 1 in the metallocene compound of formula (I) are hydrogen atoms, the group R 2 is a group >Si(CH 3 ) 2 or >Si(n-C 4 H 9 ) 2 , M is a zirconium atom and the substituents X are chlorine atoms or methyl radicals.