Heterophasic copolymer

1. A heterophasic propylene ethylene copolymer having an MFR 2 of 18.4 g/10 min to 31 g/10 min and obtained using single site catalysis comprising:

(i) a xylene insoluble fraction consisting of a mixture of different propylene homopolymers, wherein the xylene insoluble fraction is from 56.6 wt % to 70.7 wt % of the heterophasic propylene ethylene copolymer, has a MFR 2 of 35 g/10 min to 80 g/10 min, and an intrinsic viscosity of from 1.15 dl/g to 1.37 dl/g; and

(ii) 29.3 to 43.4 wt % of a xylene cold soluble fraction consisting of a single ethylene propylene rubber dispersed in the xylene insoluble fraction;

wherein the xylene cold soluble fraction has an intrinsic viscosity of 1.77 dl/g to 1.99 dl/g;

wherein the ethylene content of the xylene cold soluble fraction (C 2 (XS)) of said heterophasic propylene ethylene copolymer is between 21.8 wt % and 30 wt %;

wherein the total ethylene content of the heterophasic propylene ethylene copolymer is from 6.2 wt % to 12.7 wt %, and

wherein the heterophasic propylene ethylene copolymer has a Charpy notched impact strength at 23° C. of from 32.4 kJ/m 2 to 46.0 kJ/m 2 .

2. The heterophasic propylene ethylene copolymer as claimed in claim 1 wherein the intrinsic viscosity of the xylene cold soluble fraction divided by the intrinsic viscosity of the xylene insoluble fraction is more than 1.2 to 1.73.

3. A process for the preparation of the heterophasic propylene ethylene copolymer as claimed in claim 1 comprising polymerizing:

(I) propylene so as to form the mixture of different propylene homopolymers to form the xylene insoluble fraction; and subsequently polymerizing

(II) propylene and ethylene so as to form the ethylene propylene rubber dispersed in the xylene insoluble fraction;

wherein both steps (I) and (II) take place in the presence of the same single site solid particulate catalyst free from an external carrier.

4. The process of claim 3 in which the catalyst is prepared by obtaining a complex of formula (I) and a cocatalyst (ii);

forming a liquid/liquid emulsion system, which comprises a solution of catalyst components (i) and (ii) dispersed in a solvent, and solidifying said dispersed droplets to form solid particles,

wherein the complex of formula (I) has the structure

wherein

M is zirconium or hafnium;

each X is a sigma ligand;

L is a divalent bridge selected from —R′ 2 C—, —R′ 2 C—CR′ 2 —, —R′ 2 Si—, —R′ 2 Si—SiR′ 2 —, —R′ 2 Ge—, wherein each R′ is independently a hydrogen atom, C 1 -C 20 -hydrocarbyl, tri(C 1 -C 20 -alkyl)silyl, C 6 -C 20 -alkyl, C 7 -C 20 -arylalkyl or C 7 -C 20 -alkylaryl;

R 2 and R 2′ are each independently a C 1 -C 20 hydrocarbyl radical optionally containing one or more heteroatoms from groups 14-16;

R 5′ is a C 1-20 hydrocarbyl group containing one or more heteroatoms from groups 14-16 optionally substituted by one or more halo atoms;

R 6 and R 6′ are each independently hydrogen or a C 1-20 hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16;

R 7 and R 7′ are each independently hydrogen or C 1-20 hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16;

Ar is independently an aryl or heteroaryl group having up to 20 carbon atoms optionally substituted by one or more groups R 1 ;

Ar′ is independently an aryl or heteroaryl group having up to 20 carbon atoms optionally substituted by one or more groups R 1 ;

each R 1 is a C 1-20 hydrocarbyl group or two R 1 groups on adjacent carbon atoms taken together can form a fused 5 or 6 membered non aromatic ring with the Ar group, said ring being itself optionally substituted with one or more groups R 4 ;

each R 4 is a C 1-20 hydrocarbyl group;

and (ii) a cocatalyst comprising a compound of a group 13 metal, e.g. Al or boron compound.

5. An article comprising the heterophasic propylene ethylene copolymer of claim 1 .

6. The article of claim 5 , wherein the article is a film.