C2C3 random copolymer composition

1. A C 2 C 3 random copolymer composition comprising:

A) 70.0 to 95.0 wt % of a C 2 C 3 random copolymer having:

a) an ethylene content in a range of from 2.5 to 5.5 wt %;

b) a melt flow rate MFR 2 (230° C./2.16 kg) measured according to ISO 1133 in a range of from 4.0 to 12.0 g/10 min;

c) a melting temperature Tm as determined by DSC according to ISO 11357 of from 115° C. to 135° C. and

d) a xylene cold soluble (XCS) fraction of greater than or equal to from 0.1 wt % and less than 15.0 wt %, and

B) 5.0 to 30.0 wt % of a propylene-1-butene plastomer, which has a 1-butene content in a range of greater than or equal to from 15.0 wt % and less than 50.0 wt % based on the plastomer, having

e) a MFR 2 (230° C./2.16 kg) measured according to ISO 1133 in a range of 2.0 to 20.0 g/10 min,

f) a melting temperature Tm as determined by DSC according to ISO 11357 of from 60° C. to 110° C. and

g) a tensile modulus measured according to ASTM D638 in a range of from 50 to 450 MPa.

2. The C 2 C 3 random copolymer composition according to claim 1 , wherein the C 2 C 3 random copolymer (A) comprises:

30.0 to 70.0 wt % of polymer fraction (A-1) having:

i) an ethylene content in a range of from 1.5 to 4.5 wt % and

ii) a melt flow rate MFR 2 (230° C./2.16 kg) measured according to ISO 1133 in a range of from 4.0 to 15.0 g/10 min and

70.0 to 30.0 wt % of polymer fraction (A-2) having

i) an ethylene content in a range of from 4.6 to 7.5 wt % and

ii) a melt flow rate MFR 2 (230° C./2.16 kg) measured according to ISO 1133 in a range of from 4.0 to 15.0 g/10 min.

3. The C 2 C 3 random copolymer composition according to claim 1 , wherein the propylene-1-butene plastomer (B) has:

an MFR 2 (230° C./2.16 kg) measured according to ISO 1133 in a range of 3.0 to 15.0 g/10 min,

a melting temperature Tm as determined by DSC according to ISO 11357 of from 65° C. to 100° C. and

a tensile modulus measured according to ASTM D638 in a range of from 70 to 420 MPa.

4. The C 2 C 3 random copolymer composition according to claim 1 , wherein the propylene-1-butene plastomer (B) has a 1-butene content in a range of from 20.0 to 45.0 wt % based on the plastomer, and

a density in a range of from 860 to 900 kg/m 3 .

5. The process for producing a C 2 C 3 random copolymer composition according to claim 1 , the process comprising the steps of:

i) preparing the C 2 C 3 random copolymer (A) by polymerizing propylene and ethylene by a sequential polymerization process comprising at least two reactors connected in series in the presence of a metallocene catalyst,

ii) mixing said C 2 C 3 random copolymer (A) with a propylene-1-butene plastomer (B),

iii) optionally adding one or more additives (C), to obtain a mixture of (A), (B) and optional (C), and

iv) extruding said mixture to obtain the C 2 C 3 random copolymer composition.

6. A process for producing a C 2 C 3 random copolymer composition according to claim 5 , wherein step (i) comprises the following steps:

a) polymerizing in a first reactor (R1) propylene and ethylene, obtaining polymer fraction (A-1) of the C 2 C 3 random copolymer (A),

b) transferring said polymer fraction (A-1) and unreacted comonomers of the first reactor in a second reactor (R2),

c) feeding to said second reactor (R2) propylene and ethylene,

d) polymerizing in said second reactor (R2) and in the presence of said polymer fraction (A-1) propylene and ethylene obtaining polymer fraction (A-2),

said polymer fraction (A-1) and said polymer fraction (A-2) form the C 2 C 3 random copolymer (A), and

wherein the polymerization takes place in the presence of a metallocene catalyst comprising (i) a complex of formula (I):

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 —, or —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 -aryl, 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 is hydrogen or C 1-20 hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16 and R7′ is hydrogen;

Ar and Ar′ are each independently an aryl or heteroaryl group having up to 20 carbon atoms optionally substituted by one or more groups R1;

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 at least one or two compounds of a group 13 metal.

7. The process according to claim 6 , wherein as cocatalyst (ii) a cocatalyst system comprising a boron containing cocatalyst and an aluminoxane cocatalyst is used and the catalyst is supported on a silica support.

8. A sterilizable or sterilized article, comprising a C 2 C 3 random copolymer composition according to claim 1 .

9. The sterilizable or sterilized article according to claim 8 , wherein the article is a film and the film has:

(i) a seal initiation temperature (SIT, determined on a 50 μm cast film) in a range of greater than or equal to 80° C. and less than 110° C.,

(ii) a hot-tack force (determined on a 50 μm cast film) in a range of from 2.5 to 6.0 N,

(iii) a haze (determined according to ASTM D1003-00 on cast film with a thickness of 50 μm) of greater than or equal to 0.05% and less than 3.0%, and a haze (determined according to ASTM D 1003-00 measured on a 50 μm cast film) after sterilization (steam sterilization at 121° C. for 30 min) of greater than or equal to 1.5% and less than 7.0%, and

(iv) a clarity (determined according to ASTM D1003-00 on cast films with a thickness of 50 μm) of from 85.0% up to 100.0% and a clarity (determined according to ASTM D1003-00 on cast films with a thickness of 50 μm) after sterilization (steam sterilization at 121° C. for 30 min) of from 75.0% up to 98.0%.

10. The sterilizable or sterilized article according to claim 9 , wherein the films has:

a tensile modulus determined according to ISO 527-3 at 23° C. on cast films with a thickness of 50 μm in machine direction as well as in transverse direction in a range of 200 to 500 MPa, and/or

a relative total penetration energy (Wbreak) as determined by the “Dynatest” method according to ISO 7725-2 at 0° C. on a cast film with a thickness of 50 μm in a range of 6.0 to 20.0 J/mm, and

a relative total penetration energy (Wbreak) as determined by the “Dynatest” method according to ISO 7725-2 at +23° C. on a cast film with a thickness of 50 μm is in a range of from 20.0 to 65.0 J/mm.

11. The sterilizable or sterilized article according to claim 9 , wherein the films has:

a resistance factor (R-factor) according to formula:

R

-

factor

=

Tensile

⁢

Modulus

⁢

(

MD

)

[

MPa

]

*

HTF

[

N

]

Haze

⁢

(

b

.

s

.

)

[

%

]

of greater than 3 800 and less than or equal to 10 000, wherein:

Tensile Modulus (MD) is determined according to ISO 527-3 at 23° C. on cast films with a thickness of 50 μm in machine direction,

HTF is the hot-tack force measured on 50 μm cast film, and

Haze (b.s.) is determined according to ASTM D1003-00 on cast film with a thickness of 50 μm before sterilization.

12. A multi-layer film comprising the sterilizable or sterilized article film according to claim 9 , wherein the sterilizable or sterilized article is a film that forms a sealing layer in the multi-layer film.

13. A flexible packaging system, selected from a bag or a pouch for food and pharmaceutical packaging, comprising the sterilizable or sterilized article according to claim 9 .