# US 12,760,155 B2 · Polyolefin composition with improved impact and whitening resistance

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- Number: US 12,760,155 B2
- Document ID: US12760155B2
- Status: Granted
- Kind: B2
- Application number: 17/291,217
- Filed: 2019-10-16
- Published: 2021-11-25
- Granted: 2026-10-13
- Earliest claimed: 2018-11-07
- Assignees: Borealis AG
- Applicants: Borealis AG
- Inventors: Jingbo Wang; Markus Gahleitner; Friedrich Berger; Klaus Bernreitner; Pauli Leskinen
- Web page: https://patentgrep.com/patent/US12760155B2

## CPC

- C08J 5/18: Manufacture of films or sheets
- C08L 23/14: Copolymers of propene (C08L23/16 takes precedence)
- C08J 2323/14: Copolymers of propene (C08J2323/16 takes precedence)
- C08J 2423/08: Copolymers of ethene (C08J2423/16 takes precedence)
- C08J 2423/14: Copolymers of propene (C08J2423/16 takes precedence)
- C08L 2203/16: used for films
- C08L 2205/025: containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
- C08L 2205/035: containing four or more polymers in a blend
- C08L 2207/02: Heterophasic composition
- C08L 2314/06: Metallocene or single site catalysts
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

The invention is related to polymer compositions combining high impact strength with good haze and additionally showing good stress whitening resistance.

## Claims

### Claim 1

A polymer composition comprising:
a) 95.0 to 70.0 wt % of a heterophasic propylene copolymer (HECO) comprising 70.0 to 90.0 wt % of a polypropylene matrix (M) and 10.0 to 30.0 wt % of an elastomeric propylene copolymer (EPC) dispersed in said matrix (M),
wherein the ethylene comonomer content in the polypropylene matrix (M) is in the range of 0.0-10.0 wt % and
wherein the heterophasic propylene copolymer (HECO) has a melt flow rate MFR2 (2.16 kg, 230° C.) measured according to ISO 1133 in the range of 0.5 to 20.0 g/10 min, and
b) 5.0 to 30.0 wt % of a bi- or multimodal polyethylene (mPE) being a linear low density polyethylene (LLDPE), and being a terpolymer of ethylene and two different comonomers selected from alpha olefins 1-butene and 1-hexene, and being produced with a metallocene catalyst,
wherein the bi- or multimodal polyethylene terpolymer has:
i. an MFR2 (2.16 kg, 190° C.) measured according to ISO 1133 of 0.5 to 10.0 g/10 min,
ii. an MWD (Mw/Mn) of 2.0 to 7.0, and
iii. a density measured according to ISO 1183 of 890 to 925 kg/m3,
wherein the bi- or multimodal polyethylene (mPE) comprises a first ethylene polymer component (A) in an amount of 35 to 60 wt %, having a melt flow rate MFR2 (2.16 kg, 190° C.) measured according to ISO 1133 in the range of 1.0 to 10.0 g/10 min, and a second ethylene polymer component (B) in an amount of 40 to 65 wt %, having a melt flow rate MFR2 (2.16 kg, 190° C.) measured according to ISO 1133 in the range of 0.2 to 1.0 g/10 min,
wherein the bi- or multimodal polyethylene (mPE) is bi- or multimodal with respect to comonomer type insofar that the alpha-olefin comonomer of ethylene polymer component (A) is different from the alpha-olefin comonomer of ethylene polymer component (B), wherein the alpha-olefin comonomer of ethylene polymer component (A) is 1-butene and the alpha-olefin comonomer of ethylene polymer component (B) is 1-hexene, and
wherein the bi- or multimodal polyethylene (mPE) is bi- or multimodal with respect to comonomer content, wherein the amount of comonomer in the ethylene polymer component (A) is from 0.05 to 0.9 mol %, and whereas the amount of comonomer in the ethylene polymer component (B) is from 1.0 to 5.0 mol %.

### Claim 2 (depends on 1)

The polymer composition according to claim 1, wherein:
i. the xylene solubles fraction of the polypropylene matrix (M) is in the range of 1.0 wt % to 3.0 wt %, and/or
ii. the melt flow rate MFR2 (2.16 kg, 230° C.) measured according to ISO 1133 of the polypropylene matrix (M) is in the range of 0.3 to 30.0 g/10 min.

### Claim 3 (depends on 1)

The polymer composition according to claim 1, wherein:
i. the xylene cold soluble (XCS) content of the heterophasic propylene copolymer (HECO) determined according ISO 16152 (25° C.) is in the range of 10.0 to 30.0 wt %, and/or
ii. 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 (HECO) is in the range of 1.5 to 4.5 dl/g, and/or
iii. the ethylene comonomer content of xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO) is in the range of 20.0 to 60.0 wt %.

### Claim 4 (depends on 1)

The polymer composition according to claim 1, wherein the total ethylene comonomer content based on the amount of heterophasic propylene copolymer (HECO) is in the range of from more than 3.0 to 15.0 wt %.

### Claim 5 (depends on 1)

The polymer composition according to claim 1, wherein the bi- or multimodal polyethylene (mPE) has:
i. a Relaxation Spectrum Index (RSI) (determined as defined in the description under Experimental part using frequency sweep at 190° C.) between 3.0 and 5.5 for the density range of 915 to <920 kg/m3 (according to ISO 1183) and between 6.8 and 9.0 for the density range of 920 to 925 kg/m3 (according to ISO 1183),
ii. a normalized Relaxation Spectrum Index (nRSI) defined as RSI/MFR2 in the range of 3.0 to 10.0, and
iii. a calculated Relaxation Spectrum Index (cRSI) defined as RSI*MFR2*MWD in the range of 12.0 to 50.

### Claim 6 (depends on 1)

The polymer composition according to claim 1, wherein the bi- or multimodal polyethylene (mPE) is further bi- or multimodal with respect to a difference in density between the ethylene polymer component (A) and ethylene polymer component (B).

### Claim 7 (depends on 1)

The polymer composition according to claim 1, wherein the polymer composition has a melt flow rate MFR2 (2.16 kg, 230° C.) measured according to ISO 1133 in the range of 0.5 to 20.0 g/10 min.

### Claim 8 (depends on 1)

An article comprising a polymer composition according to claim 1.

### Claim 9 (depends on 8)

The article according to claim 8, wherein the article is a moulded article.

### Claim 10 (depends on 8)

The article according to claim 8, wherein the article is a film.

### Claim 11 (depends on 6)

The polymer composition according to claim 6, wherein the density of ethylene polymer component (A) is higher than the density of the ethylene polymer component (B); and wherein the density of the ethylene polymer component (A) being in the range of 930 to 950 kg/m3.