High flow polyolefin composition with high stiffness and toughness

Patent metadata

Field	Value
Publication number	US-9777142-B2
Application number	US-201414911300-A
Country	US
Kind code	B2
Filing date	Aug 18, 2014
Priority date	Aug 21, 2013
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

The present invention relates to a polyolefin composition comprising two heterophasic propylene copolymers which differ in the intrinsic viscosity of their xylene soluble fractions.

First claim

The invention claimed is:

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
)

Assignees

• Borealis Ag

Inventors

• Sandholzer Martina
• Kahlen Susanne
• Grestenberger Georg

Classifications

• C08L23/10 Primary

  Homopolymers or copolymers of propene · CPC title

• C08L23/14

  Copolymers of propene (C08L23/16 takes precedence) · CPC title

• C08L2207/02

  Heterophasic composition · CPC title

• C08L2205/03

  containing three or more polymers in a blend · CPC title

• C08L23/16 Primary

  Ethylene-propylene or ethylene-propylene-diene copolymers · CPC title