Polymer blends with improved processability for TPO roofing membranes and methods for making same

Patent metadata

Field	Value
Publication number	US-11629247-B2
Application number	US-202016934108-A
Country	US
Kind code	B2
Filing date	Jul 21, 2020
Priority date	Jul 23, 2019
Publication date	Apr 18, 2023
Grant date	Apr 18, 2023

Abstract

A polymer blend includes 35 to 50 wt % of at least one propylene-based elastomer, 25 to 50 wt % of at least one impact copolymer; and 15 to 25 wt % of at least one low density polyethylene component. The propylene-based elastomer has a heat of fusion less than about 80 J/g, greater than 50 wt % propylene and from about 3 wt % to about 25 wt % units derived from one or more C2 or C4-C12 α-olefins, based on a total weight of the propylene-based elastomer. The low density polyethylene has a density of about 0.90 g/cm3 to about 0.94 g/cm3. The polymer blend is useful for making a roofing membrane.

First claim

What can be claimed is:

1. A roofing membrane, comprising:
60 wt % to 70 wt % of a polymer blend comprising:
35 wt % to 50 wt % of at least one propylene-based elastomer, based on the total weight of the polymer blend, the at least one propylene-based elastomer having a heat of fusion less than about 80 J/g as determined by DSC, a density of 0.850 g/cm 3 to 0.920 g/cm 3 per ASTM D-1505, crystallinity of 2% to 65% of isotactic polypropylene and a melting point (T m ) of 100° C. or less, wherein the propylene-based elastomer comprises greater than 50 wt % propylene and from about 3 wt % to about 25 wt % units derived from one or more C 2 or C 4 -C 12 α-olefins, based on a total weight of the propylene-based elastomer;
25 wt % to 50 wt % of at least one impact copolymer, based on the total weight of the polymer blend, the at least one impact copolymer comprising a propylene homopolymer blended with a propylene copolymer; and
15 wt % to 25 wt % of at least one low density polyethylene component, based on the total weight of the polymer blend, the at least one low density polyethylene component having a density of 0.920 g/cm 3 to 0.940 g/cm 3 , a melt index @190° C./2.16 kg of about 0.20 g/10 min to about 3.0 g/10 min, as measured according to ASTM D1238, wherein the combined weight of the at least one propylene-based elastomer and the at least one low density polyethylene component is 50 wt % to 65 wt %; and

30 wt % to 40 wt % of masterbatch comprising an anti-ultraviolet agent, color pigment and fire retardant.

2. The roofing membrane of claim 1 , wherein the propylene-based elastomer has a triad tacticity greater than about 90%, as measured by 13C NMR.

3. The roofing membrane of claim 1 , wherein the propylene-based elastomer has a density of about 0.85 g/cm 3 to about 0.88 g/cm 3 .

4. The roofing membrane of claim 1 , wherein the propylene-based elastomer has a melt flow rate @230° C./2.16 kg of about 2.5 g/10 min to about 3.5 g/10 min, as measured according to ASTM D1238.

5. The roofing membrane of claim 1 , wherein the at least one impact copolymer has a melt index @230° C./2.16 kg of about 3.5 g/10 min to about 4.5 g/10 min, as measured according to ASTM D1238.

6. The roofing membrane of claim 1 , wherein the at least one impact copolymer has a density of about 0.88 g/cm 3 to about 0.95 g/cm 3 .

7. The roofing membrane of claim 1 , wherein the at least one low density polyethylene component has a melt index @190° C./2.16 kg of about 0.20 g/10 min to about 0.30 g/10 min, as measured according to ASTM D1238.

8. The roofing membrane of claim 1 , wherein the at least one low density polyethylene component has a melt index @190° C./2.16 kg of about 2.0 g/10 min to about 3.0 g/10 min, as measured according to ASTM D1238.

9. The roofing membrane of claim 1 , wherein the propylene-based elastomer comprises about 3 wt % to about 25 wt % units derived from ethylene, based on the total weight of the propylene-based elastomer.

10. The roofing membrane of claim 1 , wherein the propylene-based elastomer comprises about 3 wt % to about 15 wt % units derived from ethylene, based on the total weight of the propylene-based elastomer.

11. A roofing membrane, comprising:
a polymer blend consisting essentially of:
35 wt % to 50 wt % of at least one propylene-based elastomer, based on the total weight of the polymer blend, the at least one propylene-based elastomer having a heat of fusion less than about 80 J/g as determined by DSC, a density of 0.850 g/cm 3 to 0.920 g/cm 3 per ASTM D-1505, crystallinity of 2% to 65% of isotactic polypropylene and a melting point (T m ) of 100° C. or less, wherein the propylene-based elastomer comprises greater than 50 wt % propylene and from about 3 wt % to about 25 wt % units derived from one or more C 2 or C 4 -C 12 α-olefins, based on a total weight of the propylene-based elastomer;
25 wt % to 50 wt % of at least one impact copolymer, based on the total weight of the polymer blend, the at least one impact copolymer comprising a propylene homopolymer blended with a propylene copolymer; and
about 15 wt % of at least one low density polyethylene component, based on the total weight of the polymer blend, the at least one low density polyethylene component having a density of 0.920 g/cm 3 to 0.940 g/cm 3 , a melt index @190° C./2.16 kg of about 0.20 g/10 min to about 3.0 g/10 min, as measured according to ASTM D1238, wherein the combined weight of the at least one propylene-based elastomer and the at least one low density polyethylene component is 50 wt % to 65 wt %.

12. The roofing membrane of claim 11 , wherein the propylene-based elastomer comprises about 3 wt % to about 15 wt % units derived from ethylene, based on the total weight of the propylene-based elastomer.

13. The roofing membrane of claim 11 , further comprising 30 wt % to 40 wt % of a masterbatch comprising an anti-ultraviolet agent, color pigment and fire retardant.

14. The roofing membrane of claim 11 , wherein the propylene-based elastomer has a density of about 0.85 g/cm 3 to about 0.88 g/cm 3 and a melt flow rate @230° C./2.16 kg of about 2.5 g/10 min to about 3.5 g/10 min, as measured according to ASTM D1238.

15. The roofing membrane of claim 14 , wherein the at least one impact copolymer has a density of about 0.88 g/cm 3 to about 0.95 g/cm 3 and a melt index @230° C./2.16 kg of about 3.5 g/10 min to about 4.5 g/10 min, as measured according to ASTM D1238.

16. A roofing membrane, comprising:
a polymer blend consisting essentially of:
35 wt % to 50 wt % of at least one propylene-based elastomer, based on the total weight of the polymer blend, the at least one propylene-based elastomer having a heat of fusion less than about 80 J/g as determined by DSC, a density of 0.850 g/cm 3 to 0.920 g/cm 3 per ASTM D-1505, crystallinity of 2% to 65% of isotactic polypropylene and a melting point (T m ) of 100° C. or less, wherein the propylene-based elastomer comprises greater than 50 wt % propylene and from about 3 wt % to about 25 wt % units derived from one or more C 2 or C 4 -C 12 α-olefins, based on a total weight of the propylene-based elastomer;
25 wt % to 50 wt % of at least one impact copolymer, based on the total weight of the polymer blend, the at least one impact copolymer comprising a propylene homopolymer blended with a propylene copolymer; and
about 25 wt % of at least one low density polyethylene component, based on the total weight of the polymer blend, the at least one low density polyethylene component having a density of 0.920 g/cm 3 to 0.940 g/cm 3 , a melt index @190° C./2.16 kg of about 0.20 g/10 min to about 0.3 g/10 min, as measured according to ASTM D1238, wherein the combined weight of the at least one propylene-based elastomer and the at least one low density polyethylene component is 50 wt % to 65 wt %.

17. The roofing membrane of claim 16 , wherein the propylene-based elastomer comprises about 3 wt % to about 15 wt % units derived from ethylene, based on the total weight of the propylene-based elastomer.

18. The roofing membrane of claim 16 , further comprising 30 wt % to 40 wt % of a masterbatch comprising an anti-ultraviolet agent, color pigment and fire retardant.

19. The roofing membrane of claim 16 , wherein the propylene-based elastomer has a density of about 0.85 g/cm 3 to about 0.88 g/cm 3 and a melt flow rate @230° C./2.16 kg of about 2.5 g/10 min to about 3.5 g/10 min, as measured according to ASTM D1238.

20. The roofing membrane of claim 19 , wherein the at least one impact copoly

Assignees

• Exxonmobil Chemical Patents Inc
• Exxonmobil Chemicals Patents Inc

Inventors

• Qian Chen
• Cevallos Dayana M
• Zacarias Felix M

Classifications

• C08L23/14

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

• E04D5/06

  by making use of plastics · CPC title

• C08L23/06

  Polyethylene · CPC title

• C08L2310/00

  Masterbatches · CPC title

• C08L23/12

  Polypropene · CPC title