Soft and transparent propylene compolymers

1. A polypropylene composition (C), comprising

i) a heterophasic propylene copolymer (RAHECO), said heterophasic propylene copolymer comprising a matrix (M) being a random propylene copolymer (R-PP) and an elastomeric propylene copolymer (E) dispersed in said matrix (M),

and

ii) a plastomer (PL) being a copolymer of ethylene and at least one C4 to C20 α-olefin having a density below 0.900 g/cm 3 ,

wherein the random propylene copolymer (R-PP) comprises a first propylene copolymer fraction (R-PP1) and a second propylene copolymer fraction (R-PP2) and the comonomer contents of the random propylene copolymer (R-PP) and the first propylene copolymer fraction (R-PP1) fulfil inequation (IIIb),

C

⁢

o

⁡

(

R

⁢

P

⁢

P

)

C

⁢

o

⁡

(

R

⁢

P

⁢

P

⁢

1

)

≥

1.4

,

(

III

⁢

b

)

wherein Co(RPP) is the comonomer content of the random propylene copolymer (R-PP) and Co(RPP1) is the comonomer content of the first propylene copolymer fraction (R-PP1), and wherein the first propylene copolymer fraction (R-PP1) is lean in comonomer compared to the second propylene copolymer fraction (R-PP2).

2. The polypropylene composition (C) according to claim 1 , wherein the polypropylene composition (C) has at least two glass transition temperatures Tg(1) and Tg(2), the first glass transition temperature Tg(1) relates to the matrix (M) while the second glass transition temperature Tg(2) relates to the dispersed elastomeric propylene copolymer (E), wherein further the second glass transition temperature fulfils the inequation (II),

Tg (2)>9.0−2.0× C (XCS)  (II)

wherein

Tg(2) is the second glass transition temperature of the polypropylene composition (C) and C(XCS) is the comonomer content [in mol-%] of the xylene cold soluble fraction (XCS) of the polypropylene composition (C).

3. The polypropylene composition (C) according to claim 1 , having at least two glass transition temperatures Tg(1)′ and Tg(2)′, wherein the second glass transition temperature fulfils the inequation (I),

Tg (2)′>10.0−1.8× C (XCS)′  (I)

wherein

Tg(2)′ is the second glass transition temperature of the polypropylene composition (C) and C(XCS)′ is the propylene content [in mol-%] of the xylene cold soluble fraction (XCS) of the polypropylene composition (C).

4. The polypropylene composition (C) according to claim 1 , wherein the melt flow rate MFR 2 (230° C./2.16 kg) measured according to ISO 1133 of the polypropylene composition (C) is in the range of 1.0 to 30 g/10 min.

5. The polypropylene composition (C) according to claim 1 , wherein the polypropylene composition (C) has at least one of:

i) a xylene soluble content (XCS) in the range of 10.0 to 45.0 wt.-%, or

ii) a propylene content in the range of 65.0 to 96.0 mol-%.

6. The polypropylene composition (C) according to claim 1 , wherein the polypropylene composition (C) has a melting temperature of at least 135° C.

7. The polypropylene composition (C) according to claim 1 , wherein the polypropylene composition (C) has at least one of:

i) a flexural modulus measured according to ISO 178 below 600 MPa or

ii) a haze according to ASTM D 1300-00 measured on a 50 μm thick cast film below 3.0%.

8. The polypropylene composition (C) according to claim 1 , wherein the polypropylene composition (C) has

an intrinsic viscosity (IV) determined according to DIN ISO 1628/1 (in Decalin at 135° C.) of the xylene soluble content (XCS) in the range of 0.7 to 2.0 dl/g.

9. The polypropylene composition (C) according to claim 1 , comprising 60 to 99 wt.-% of the heterophasic propylene copolymer (RAHECO) and 1 to 40 wt.-% of the plastomer (PL).

10. The polypropylene composition (C) according to claim 1 , wherein the comonomers of at least one of: the random propylene copolymer (R-PP) or the elastomeric propylene copolymer (E) are at least one of: ethylene or C 4 to C 8 α-olefins.

11. The polypropylene composition (C) according to claim 1 , wherein the heterophasic propylene copolymer (RAHECO) has at least one of:

a) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 2.0 to 25.0 g/10 min, or

b) a xylene soluble content (XCS) in the range of 10.0 to 40.0 wt.-%, or

c) a comonomer content in the range of 1.5 to 20.0 mol-%.

12. The polypropylene composition (C) according to claim 1 , wherein the comonomer of the plastomer (PL) is 1-octene.

13. The polypropylene composition (C) according to claim 1 , wherein the plastomer (PL) has a melt flow rate MFR (190° C./2.16 kg) measured according to ISO 1133 below 50 g/10 min.

14. A film, comprising a polypropylene composition (C), the polypropylene composition comprising

i) a heterophasic propylene copolymer (RAHECO), said heterophasic propylene copolymer comprising a matrix (M) being a random propylene copolymer (R-PP)

and an elastomeric propylene copolymer (E) dispersed in said matrix (M),

and

ii) a plastomer (PL) being a copolymer of ethylene and at least one C 4 to C 20 α-olefin having a density below 0.900 g/cm 3 ,

wherein the random propylene copolymer (R-PP) comprises a first propylene copolymer fraction (R-PP1) and a second propylene copolymer fraction (R-PP2) and the comonomer contents of the random propylene copolymer (R-PP) and the first propylene copolymer fraction (R-PP1) fulfil inequation (IIIb),

C

⁢

o

⁡

(

R

⁢

P

⁢

P

)

C

⁢

o

⁡

(

R

⁢

P

⁢

P

⁢

1

)

≥

1.4

,

(

III

⁢

b

)

wherein Co(RPP) is the comonomer content of the random propylene copolymer (R-PP) and Co(RPP1) is the comonomer content of the first propylene copolymer fraction (R-PP1), and wherein the first propylene copolymer fraction (R-PP1) is lean in comonomer compared to the second propylene copolymer fraction (R-PP2).

15. A polymerization process for producing the polypropylene composition (C) according to claim 1 , comprising the steps of

a) providing a plastomer (PL) being a copolymer of ethylene and at least one C 4 to C 20 α-olefin,

b) polymerizing in a first reactor (R1) propylene and at least one of: ethylene or a C 4 to C 8 α-olefin, obtaining a first random propylene copolymer fraction (R-PP1),

c) transferring the first random propylene copolymer fraction (R-PP1) into a second reactor (R2),

d) polymerizing in said second reactor (R2) in the presence of the first random propylene copolymer fraction (R-PP1) propylene and at least one of: ethylene or a C 4 to C 8 α-olefin, obtaining a second random copolymer fraction (R-PP2), said first random propylene copolymer fraction (R-PP1) and said second random copolymer fraction (R-PP2) forming the random propylene copolymer (R-PP),

e) transferring said random propylene copolymer (R-PP) into a third reactor (R3),

f) polymerizing in said third reactor (R3) in the presence of at least one of: the random propylene copolymer (R-PP) propylene or a C 4 to C 8 α-olefin, obtaining a third polymer fraction, said polymer fraction is the elastomeric copolymer (E), said propylene copolymer (R-PP) and said elastomeric propylene copolymer (E) form the heterophasic propylene copolymer (RAHECO),

g) melt blending the heterophasic propylene copolymer (RAHECO) obtained in step f) with the plastomer (PL) of step a).

16. The polypropylene composition (C) according to claim 11 , wherein the heterophasic propylene copolymer (RAHECO) has a xylene soluble content (XCS) in the range of 10.0 to 40.0 wt.-%, having a comonomer content below 50 mol-%.