Polymer composition with high XS, high Tm suitable for BOPP processing

1. A polypropylene copolymer (R-PP) having

(a) a comonomer content in the range from 0.1 to 3.0 mol-% based on the weight of the polypropylene copolymer (R-PP), wherein the comonomer is ethylene,

(b) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range from 1.0 to 10.0 g/10min,

(c) a melting temperature T m of more than 150.0° C. and

(d) an isotacticity of not more than 92.0%,

(e) a xylene cold soluble fraction (XCS) in the range from 4.0 to 10.0 wt.-%.

2. The polypropylene copolymer (R-PP) according to claim 1 , wherein the polypropylene copolymer (R-PP) has

(a) a Vicat A softening point of below 154.0° C. and/or

(b) a molecular weight distribution (MWD) in the range of 3.0 to 10.0.

3. The polypropylene copolymer (R-PP) according to claim 1 , wherein said polypropylene copolymer (R-PP) comprises two fractions, a first propylene homopolymer fraction (R-PP1) and a second propylene copolymer fraction (R-PP2), wherein said first propylene homopolymer fraction (R-PP1) differs from said second propylene copolymer fraction (R-PP2) in the melt flow rate.

4. The polypropylene copolymer (R-PP) according to claim 3 , wherein

(a) the first propylene homopolymer fraction (R-PP1) and the second propylene copolymer fraction (R-PP2) fulfill together the inequation (Ia),

MFR

⁡

(

R

-

PP

⁢

⁢

1

)

MFR

⁡

(

R

-

PP

⁢

⁢

2

)

≥

1.5

(

Ia

)

wherein

MFR (R-PP1) is the melt flow rate MFR 2 (230° C.) [g/10min] of the first propylene homopolymer fraction (R-PP1) and

MFR (R-PP2) is the melt flow rate MFR 2 (230° C.) [g/10min] of the second propylene copolymer fraction (R-PP2)

and/or

(b) the polypropylene copolymer (R-PP) and the second propylene copolymer fraction (R-PP2) fulfill together the inequation (IIa)

MFR

⁡

(

R

-

PP

⁢

⁢

1

)

MFR

⁡

(

R

-

PP

)

≥

1.3

(

IIa

)

wherein

MFR (R-PP) is the melt flow rate MFR 2 (230° C.) [g/10min] of the polypropylene copolymer (R-PP) and

MFR (R-PP1) is the melt flow rate MFR 2 (230° C.) [g/10min] of the first propylene homopolymer fraction (R-PP1).

5. The polypropylene copolymer (R-PP) according to claim 3 , wherein the second propylene copolymer fraction (R-PP2) has a comonomer content in the range from more than 0.1 to 6.0 mol-%.

6. The polypropylene copolymer (R-PP) according to claim 3 , wherein the first propylene homopolymer fraction (R-PP1) has a higher melt flow rate than the second propylene copolymer fraction (R-PP2).

7. A process for preparing a polypropylene copolymer (R-PP) according to claim 3 , comprising a first propylene homopolymer fraction (R-PP1) and a second propylene copolymer fraction (R-PP2), wherein said process is a sequential polymerization process comprising at least two reactors connected in series, wherein said process comprises the steps of

(a) polymerizing in a first reactor (R-1)

(a1) propylene obtaining thereby said first propylene homopolymer fraction (R-PP1),

(b) transferring said first propylene homopolymer fraction (R-PP1) and unreacted monomers from the first reactor (R-1) into a second reactor (R-2),

(c) feeding to said second reactor (R-2)

(c1) propylene and

(c2) ethylene,

(d) polymerizing in said second reactor (R-2) and in the presence of said first propylene homopolymer fraction (R-PP1)

(d1) propylene and

(d2) ethylene,

obtaining said polypropylene copolymer (R-PP) comprising the first propylene homopolymer fraction (R-PP1) and the second propylene copolymer fraction (R-PP2),

wherein the polymerization takes place in the presence of a solid catalyst system (SCS), said solid catalyst system (SCS) comprises

(i) a transition metal (TM) selected from one of the groups 4 to 6 of the periodic table (IUPAC),

(ii) a metal which is selected from one of the groups 1 to 3 of the periodic table (IUPAC),

(iii) an internal electron donor (ID)

(iv) a cocatalyst (Co), and

(v) an external donor (ED).

8. The process according to claim 7 , wherein the solid catalyst system (SCS) comprises a cocatalyst (Co) and a transition metal (TM) in the molar ratio [(Co)/(TM)] above 95.

9. The process according to claim 7 , wherein the solid catalyst system (SCS) comprises a cocatalyst (Co) and a an external donor (ED) in the molar ratio [(Co)/(ED)] above 50.

10. The process according to claim 7 , wherein the solid catalyst system (SCS) comprises an external donor (ED) and a transition metal (TM) in the molar ratio [(ED)/(TM)] below 10.

11. A biaxially oriented polymer film comprising a polypropylene copolymer (R-PP) according to claim 1 .

12. A process for preparing a biaxially oriented polypropylene (BOPP) according to claim 11 comprising the steps of

(a) preparing a polypropylene copolymer (R-PP),

(b) preparing a film comprising the polypropylene copolymer (R-PP), and

(c) biaxially orienting the film.