High flow polyolefin composition with high stiffness and toughness

1. A polyolefin composition comprising

(a) a first heterophasic propylene copolymer (HECO1) having

(i) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 15.0 to 55.0 g/10min, and

(ii) a xylene cold soluble content (XCS) determined according ISO 16152 (25° C.) in the range of 24 to 38 wt.-%, wherein further

(iii) the intrinsic viscosity (IV) determined according to DIN ISO 1628/1 (in decalin at 135° C.) of the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO1) is in the range of 2.0 to 3.5 dl/g, and

(b) a second heterophasic propylene copolymer (HECO2) comprising a propylene homopolymer (H-PP2) and an elastomeric propylene copolymer (E2), wherein

(i) the propylene homopolymer (H-PP2) has a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of above 15 to 400 g/10min;

(ii) the xylene cold soluble (XCS) fraction of the second heterophasic propylene copolymer (HECO2) has an intrinsic viscosity determined according to DIN ISO 1628/1 (in decalin at 135° C.) in the range of more than 3.7 to 9.0 dl/g; and

(iii) the comonomer content of the xylene cold soluble (XCS) fraction of the second heterophasic propylene copolymer (HECO2) is in the range of 10.0 to 40.0 wt.-%.

2. The polyolefin composition according to claim 1 , wherein the second heterophasic propylene copolymer (HECO2) has

(a) a xylene cold soluble content (XCS) determined according ISO 16152 (25° C.) of below 40 wt.-%, and/or

(b) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 1.0 to 150 g/10min.

3. The polyolefin composition according to claim 1 , wherein the second heterophasic propylene copolymer (HECO2) fulfills the in-equation (IV)

0.50

≥

(

0.241

×

c

wt

.

-

⁢

%

)

-

(

1.14

×

IV

dl

⁢

/

⁢

g

)

(

IV

)

wherein

C is the comonomer content in wt.-% of the xylene cold soluble (XCS) fraction of the second heterophasic propylene copolymer (HECO2), and

IV is the intrinsic viscosity in dl/g of the xylene cold soluble (XCS) fraction of the second heterophasic propylene copolymer (HECO2).

4. The polyolefin composition according to claim 1 , wherein

(i) the first heterophasic propylene copolymer (HECO1) has a comonomer content in the range of 6.0 to 17.0 wt.-%, and/or

(ii) the comonomer content of the xylene cold soluble (XCS) fraction of the first heterophasic propylene copolymer (HECO1) is in the range of 26 to 40 wt.-%.

5. The polyolefin composition according to claim 1 , wherein the second heterophasic propylene copolymer (HECO2) has a comonomer content below 20.0 wt.-%.

6. The polyolefin composition according to claim 1 , wherein the first heterophasic propylene copolymer (HECO1) comprises a polypropylene (PP 1) as matrix and an elastomeric propylene copolymer (E1) dispersed in the matrix.

7. The polyolefin composition according to claim 1 , wherein

(i) the polyolefin composition comprises the first heterophasic propylene copolymer (HECO1) and the second heterophasic propylene copolymer (HECO2) in a weight ratio [(HECO1):(HECO2)] of 1.2:1 to 15:1, and/or

(ii) the two heterophasic propylene copolymers (HECO1) and (HECO2) make up at least 50 wt.-%, preferably at least 70 wt.-%, of the polyolefin composition.

8. An automotive article comprising at least to 60 wt.-% of the polyolefin composition according to claim 1 .

9. The automotive article according to claim 8 , wherein the automotive article is selected from the group consisting of bumpers, side trims, step assists, body panels, spoilers, dashboards, and interior trims.

10. The polyolefin composition according to claim 2 , wherein the second heterophasic propylene copolymer (HECO2) has

(a) a xylene cold soluble content (XCS) determined according ISO 16152 (25° C.) of 8.0 to 35 wt.-%, and/or

(b) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 1.0 to 150 g/10min.

11. The polyolefin composition according to claim 6 , wherein

(i) the polypropylene (PP1) is a propylene homopolymer (H-PP1), and/or

(ii) the polypropylene (PP1) has a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 of 60 to 400 g/10min.

12. The polyolefin composition according to claim 2 , wherein the second heterophasic propylene copolymer (HECO2) fulfills the in-equation (IV)

0.50

≥

(

0.241

×

c

wt

.

-

⁢

%

)

-

(

1.14

×

IV

dl

⁢

/

⁢

g

)

(

IV

)

wherein

C is the comonomer content in wt.-% of the xylene cold soluble (XCS) fraction of the second heterophasic propylene copolymer (HECO2), and

IV is the intrinsic viscosity in dl/g of the xylene cold soluble (XCS) fraction of the second heterophasic propylene copolymer (HECO2).

13. The polyolefin composition according to claim 2 , wherein

(i) the first heterophasic propylene copolymer (HECO1) has a comonomer content in the range of 6.0 to 17.0 wt.-%, and/or

(ii) the comonomer content of the xylene cold soluble (XCS) fraction of the first heterophasic propylene copolymer (HECO1) is in the range of 26 to 40 wt.-%.

14. The polyolefin composition according to claim 2 , wherein the second heterophasic propylene copolymer (HECO2) has a comonomer content below 20.0 wt.-%.

15. The polyolefin composition according to claim 2 , wherein the first heterophasic propylene copolymer (HECO1) comprises a polypropylene (PP1) as matrix and an elastomeric propylene copolymer (E1) dispersed in the matrix.

16. The polyolefin composition according to claim 2 , wherein

(i) the polyolefin composition comprises the first heterophasic propylene copolymer (HECO1) and the second heterophasic propylene copolymer (HECO2) in a weight ratio [(HECO1):(HECO2)] of 1.2:1 to 15:1, and/or

(ii) the two heterophasic propylene copolymers (HECO1) and (HECO2) make up at least 50 wt.-%, preferably at least 70 wt.-%, of the polyolefin composition.