High flow TPO composition with excellent tensile strain at break and low powder stickiness

1. A heterophasic propylene copolymer (HECO) comprising

a) a propylene homopolymer (HPP) having a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 100 to 300 g/10 min, and

b) an elastomeric propylene-ethylene copolymer (E),

wherein the heterophasic propylene copolymer (HECO)

(i) has a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 20 to 35 g/10 min,

(ii) comprises a xylene cold soluble (XCS) fraction in an amount from 28 to 38 wt.-%, based on the total weight of the heterophasic propylene copolymer (HECO),

wherein further the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO) has

(iii) an intrinsic viscosity (IV) in the range of 2.5 to 3.5 dl/g, and

(iv) an ethylene content (EC) of 15 to 35 wt.-% based on the total weight of the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO).

2. The heterophasic propylene copolymer (HECO) according to claim 1 , wherein the propylene homopolymer (HPP) is unimodal with respect to the melt flow rate MFR 2 (230° C.) measured according to ISO 1133, has a xylene cold soluble (XCS) content no higher than 5 wt.-%, or is unimodal with respect to the melt flow rate MFR 2 (230° C.) measured according to ISO 1133 and has a xylene cold soluble (XCS) content no higher than 5 wt.-%.

3. The heterophasic propylene copolymer (HECO) according to claim 1 , wherein the heterophasic propylene copolymer (HECO) has an ethylene content (EC-HECO) of 7 to 15 wt.-%, based on the total weight of the heterophasic propylene copolymer (HECO).

4. The heterophasic propylene copolymer (HECO) according to claim 1 , wherein the xylene cold soluble (XCS) fraction is unimodal with respect to the ethylene content (EC), unimodal with respect to a molecular weight distribution (MWD), or unimodal with respect to the ethylene content (EC) and with respect to the molecular weight distribution (MWD).

5. The heterophasic propylene copolymer (HECO) according to claim 1 , wherein the weight ratio of heterophasic propylene copolymer (HECO) to the polypropylene homopolymer (HPP) [HECO/HPP] is from 3.0:1.0 to 1.0:1.0.

6. The heterophasic propylene copolymer (HECO) according to claim 1 , wherein the heterophasic propylene copolymer (HECO) is α-nucleated.

7. A polyolefin composition (PO) comprising ≥95 wt.-%, based on the total weight of the composition, of the heterophasic propylene copolymer (HECO) according to claim 1 .

8. The polyolefin composition (PO) according to claim 7 , wherein the composition comprises an inorganic filler (F).

9. The polyolefin composition (PO) according to claim 7 , wherein the composition has

i) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 20 to 35 g/10 min, and one or more of:

ii) a tensile modulus of ≥750 MPa, or

iii) a Charpy Notched impact strength at 23° C. of ≥30 kJ/m2, or

iv) a tensile strain at break of ≥150%.

10. The polyolefin composition (PO) according to claim 9 , wherein the composition has one or more of:

i) a tensile modulus in the range of 750 to 1100 MPa, or

ii) a Charpy Notched impact strength at 23° C. in the range of 30 to 80 kJ/m2, or

iii) a tensile strain at break in the range of 150 to 400%.

11. An automotive article comprising at least one of a heterophasic propylene copolymer (HECO) and a polyolefin composition (PO),

wherein the heterophasic propylene copolymer (HECO) comprises

a) a propylene homopolymer (HPP) having a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 100 to 300 g/10 min, and

b) an elastomeric propylene-ethylene copolymer (E),

wherein the heterophasic propylene copolymer (HECO)

(i) has a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 20 to 35 g/10 min,

(ii) comprises a xylene cold soluble (XCS) fraction in an amount from 28 to 38 wt.-%, based on the total weight of the heterophasic propylene copolymer (HECO),

wherein further the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO) has

(iii) an intrinsic viscosity (IV) in the range of 2.5 to 3.5 dl/g, and

(iv) an ethylene content (EC) of 15 to 35 wt.-% based on the total weight of the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO), and

wherein the polyolefin composition (PO) comprises ≥95 wt.-%, based on the total weight of the polyolefin composition (PO) of the heterophasic propylene copolymer (HECO).

12. The automotive article according to claim 11 , wherein the automotive article is an exterior or interior automotive article selected from bumpers, body panels, rocker panels, side trim panels, interior trims, step assists, spoilers, fenders and dash boards.

13. A process for the preparation of a polyolefin composition (PO) according to claim 7 , the process comprising extruding the heterophasic propylene copolymer (HECO) and the optional inorganic filler (F) in an extruder.

14. The process according to claim 13 , wherein the heterophasic propylene copolymer (HECO) is obtained by producing the propylene homopolymer (HPP) in at least one reactor, transferring said propylene homopolymer (HPP) in at least one subsequent reactor, and producing the elastomeric propylene-ethylene copolymer (E) in the presence of the propylene homopolymer (HPP).

15. A method comprising improving the mechanical properties of a polyolefin composition (PO) with the heterophasic propylene copolymer (HECO) according to claim 1 , wherein the improvement is achieved when the composition has

i) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 20 to 35 g/10 min, and one or more of

ii) a tensile modulus of ≥750 MPa, or

iii) a Charpy Notched impact strength at 23° C. of ≥30 kJ/m2, or

iv) a tensile strain at break of ≥150%.

16. The heterophasic propylene copolymer (HECO) according to claim 6 , wherein the heterophasic propylene copolymer (HECO) comprises a α-nucleating agent.

17. The polyolefin composition (PO) according to claim 8 , wherein the inorganic filler (F) is selected from the group consisting of talc, wollastonite, mica, chalk and mixtures thereof.

18. The polyolefin composition (PO) according to claim 8 , wherein the composition has

i) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 20 to 35 g/10 min, and one or more of:

ii) a tensile modulus of ≥750 MPa, or

iii) a Charpy Notched impact strength at 23° C. of ≥30 kJ/m2, or

iv) a tensile strain at break of ≥150%.

19. The polyolefin composition (PO) according to claim 18 , wherein the composition has one or more of:

i) a tensile modulus in the range of 750 to 1100 MPa, or

ii) a Charpy Notched impact strength at 23° C. in the range of 30 to 80 kJ/m2, or

iii) a tensile strain at break in the range of 150 to 400%.