High flow automotive exterior compounds with excellent surface appearance

Patent metadata

Field	Value
Publication number	US-11111371-B2
Application number	US-201716317162-A
Country	US
Kind code	B2
Filing date	Jul 14, 2017
Priority date	Jul 25, 2016
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

The present invention is directed to propylene composition applicable for high flow automotive exterior compounds with excellent surface appearance, said composition comprising a modified polypropylene composition and an inorganic filler.

First claim

The invention claimed is:

1. A composition comprising a modified polypropylene composition and an inorganic filler, wherein the modified polypropylene composition is obtained by treatment of a polypropylene composition with a peroxide (PO), the polypropylene composition comprising:
(a) a heterophasic composition, comprising:
(a1) a (semi)crystalline polypropylene, and
(a2) an elastomeric ethylene/propylene copolymer dispersed in the (semi)crystalline polypropylene,

(b) a plastomer being a copolymer of ethylene and at least one C4 to C20 α-olefin, and
(c) optionally a high flow polypropylene, the high flow polypropylene having a higher melt flow rate MFR 2 (230° C.), measured according to ISO 1133, than the (semi)crystalline polypropylene,
wherein the modified polypropylene composition has:
(i) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 above 32 g/10 min, and
(ii) an intrinsic viscosity determined according to DIN ISO 1628/1 (in Decalin at 135° C.) of the xylene soluble fraction below 2.30 dl/g and
(iii) an intrinsic viscosity determined according to DIN ISO 1628/1 (in Decalin at 135° C.) of the xylene insoluble fraction below 1.05 dl/g.

2. The composition according to claim 1 , wherein the plastomer is a copolymer of ethylene and 1-butene or 1-octene.

3. The composition according to claim 1 , wherein the weight ratio of the heterophasic composition and the plastomer in the polypropylene composition is in the range of 0.1 to 10.0.

4. The composition according to claim 1 , wherein the polypropylene composition comprises 3 to 15 wt.-%, based on the overall weight of the polypropylene composition, of the high flow polypropylene having a higher melt flow rate MFR 2 (230° C.), measured according to ISO 1133, than the (semi)crystalline polypropylene.

5. The composition according to claim 1 , comprising:
(a) 45 to 95 wt.-% of the modified polypropylene composition, and
(b) 5 to 30 wt.-% of the inorganic filler (F),
based on the overall weight of the composition (C).

6. The composition according to claim 1 , wherein the heterophasic composition has:
(a) a comonomer content, based on the total weight of the heterophasic composition (HECO), in the range of 3 to 20 wt.-%,
and/or
(b) a xylene soluble fraction in the range of 10 to 35 wt.-%,
and/or
(c) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 from 40 to 100 g/10 min.

7. The composition according to claim 1 , wherein the xylene soluble fraction of the heterophasic composition has:
(a) an intrinsic viscosity determined according to DIN ISO 1628/1 (in Decalin at 135° C.) in the range of 1.5 to 4.5 dl/g, and
(b) a comonomer content, based on the total weight of the xylene soluble fraction of the heterophasic composition, in the range of 25 to 55 wt.-%.

8. The composition according to claim 1 , wherein the plastomer has
(a) a melt flow rate MFR (190° C.) measured according to ISO 1133 from 0.05 to 5.0 g/10 min,
(b) a comonomer content, based on the total weight of the plastomer, in the range of 5 to 25 mol-%, and
(c) a density equal or below 0.880 g/cm 3 .

9. The composition according to claim 1 , wherein the inorganic filler is talc.

10. An injection moulded automotive article comprising a composition comprising:
a modified polypropylene composition and an inorganic filler, wherein the modified polypropylene composition is obtained by treatment of a polypropylene composition with a peroxide (PO), the polypropylene composition comprising:
(a) a heterophasic composition, comprising:
(a1) a (semi)crystalline polypropylene, and
(a2) an elastomeric ethylene/propylene copolymer dispersed in the (semi)crystalline polypropylene,

(b) a plastomer being a copolymer of ethylene and at least one C4 to C20 α-olefin, and
(c) optionally a high flow polypropylene, the high flow polypropylene having a higher melt flow rate MFR 2 (230° C.), measured according to ISO 1133, than the (semi)crystalline polypropylene,
wherein the modified polypropylene composition has:
(i) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 above 32 g/10 min, and
(ii) an intrinsic viscosity determined according to DIN ISO 1628/1 (in Decalin at 135° C.) of the xylene soluble fraction below 2.30 dl/g and
(iii) an intrinsic viscosity determined according to DIN ISO 1628/1 (in Decalin at 135° C.) of the xylene insoluble fraction below 1.05 dl/g.

11. A process for the preparation of the composition according to claim 1 , wherein
(a)
(a1) the polypropylene composition comprising the heterophasic composition, the plastomer and optionally the high flow polypropylene is extruded in an extruder in the presence of the peroxide to obtain the modified polypropylene composition, and
(b1) the modified polypropylene composition is melt blended with the inorganic filler,
or

(b) the polypropylene composition comprising the heterophasic composition, the plastomer, optionally the high flow polypropylene, and the inorganic filler are extruded in an extruder in the presence of the peroxide.

12. The process of claim 11 , wherein the peroxide reduces tigerskin in the polypropylene composition.

13. The process according to claim 12 , wherein the reduction of tigerskin is characterized by a mean square error values equal to or below 30 for a gray scale image of the polypropylene composition.

Assignees

• Borealis Ag

Inventors

• Lummerstorfer Thomas
• Mileva Daniela
• Grestenberger Georg

Classifications

• C08L2205/035

  containing four or more polymers in a blend · CPC title

• C08L2207/02

  Heterophasic composition · CPC title

• C08L23/12 Primary

  Polypropene · CPC title

• C08L23/14

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

• C08L23/142

  at least partially crystalline copolymers of propene with other olefins · CPC title