Thermoplastic olefinic compositions
Thermoplastic olefinic compositions comprising (a) at least one ethylene/α-olefin polymer having a PRR between 8 and 70 and (b) at least one polypropylene polymer and an (a)/(b) weight ratio of greater than 50/less than 50 to 90/10. The compositions are used in extrusion, calendering, blow molding, foaming and thermoforming processes to make a variety of articles, such as automotive instrument panel skins.
1. A thermoplastic composition comprising the following:
at least one ethylene/alpha-olefin interpolymer having a PRR between about 8 and 70, a melt strength of at least 5 cN, a density less than 0.91 g/cc, and a “0.1 radian per second, at 190° C., viscosity” of at least 200,000 poise; and
at least one polypropylene polymer selected from the group consisting of polypropylene homopolymers and propylene/alpha-olefin interpolymers, and wherein the weight ratio of ethylene/alpha-olefin interpolymer to polypropylene polymer in the composition being from “greater than 50: less than 50” to 90:10, and
wherein the thermoplastic composition comprises a “190° C. shear thinning index (STI)” of 20 or more, and two of the three following heat related characteristics:
a) a 140° C. stress strain slope of 0.20 or more;
b) an upper service temperature (UST) of 115° C. or more; and
c) a 120° C. hot creep elongation at 8.7 psi of less than 100%; and
wherein the ethylene/alpha-olefin interpolymer has T-type long chain branching.
2. The composition of claim 1 , wherein the ethylene/alpha-olefin interpolymer is an ethylene/alpha-olefin copolymer.
3. The composition of claim 2 , wherein the ethylene/α-olefin copolymer has a PRR greater than 12.
4. The composition of claim 2 , wherein the ethylene/α-olefin copolymer has a PRR greater than 15.
5. The composition of claim 2 , wherein the ethylene/α-olefin copolymer has a PRR greater than 18.
6. The composition of claim 2 , wherein the polypropylene polymer has a melting point greater than 145° C.
7. The composition of claim 6 , wherein the thermoplastic composition has creep resistance of less than 100% at 120° C.
8. The composition of claim 2 , wherein the ethylene/α-olefin copolymer was polymerized by at least one metallocene catalyst.
9. The composition of claim 2 , further comprising up to 20% of at least one elastomer containing a branching agent.
10. The composition of claim 2 , further comprising up to 20% of at least one elastomeric polypropylene homopolymer or copolymer.
11. The composition of claim 2 , wherein at least one polypropylene polymer is a nucleated polymer.
12. The composition of claim 2 , wherein at least one polypropylene polymer is a branched polymer.
13. The composition of claim 2 , having a 120° C. hot creep elongation @ 8.7 psi of less than 50%.
14. An article of manufacture, comprising at least one component or part formed from the Composition of claim 1 .
15. The article of claim 14 , wherein the article is made by a blow molding process.
16. The article of claim 14 , wherein the article is a blown film.
17. The article of claim 14 , wherein the article is made by a calendering process.
18. The article of claim 14 , wherein the article is a thermoformed article.
19. The article of claim 18 , wherein the article is an automotive interior part.
20. The article of claim 19 , wherein the article is an instrument panel skin.
21. The article of claim 19 , wherein the article is a door panel skin.
22. The article of claim 19 , wherein the article is seat trim.
23. The article of claim 14 , wherein the article is made by an extrusion process.
24. The article of claim 17 or claim 23 , wherein the article is a vacuum formed profile.
25. The article of claim 24 , wherein the article is a refrigerator gasket.
26. The composition of claim 1 , wherein the weight ratio of ethylene/alpha-olefin interpolymer to polypropylene polymer is from 60:40 to 90:10.
27. The composition of claim 1 , wherein the alpha-olefin is a C3-C10 alpha-olefin.
28. The composition of claim 2 , wherein the ethylene/alpha-olefin copolymer is selected from an ethylene/propylene copolymer, an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, or an ethylene/1-octene copolymer.
29. The composition of claim 28 , wherein the ethylene/alpha-olefin copolymer is selected from an ethylene/1-butene copolymer, or an ethylene/1-octene copolymer.
30. An article of manufacture comprising at least one component or part formed from the composition of claim 2 .
31. A thermoplastic composition comprising the following:
at least one ethylene/alpha-olefin copolymer, selected from ethylene/propylene copolymers, ethylene/butene copolymers, ethylene/hexene copolymers or ethylene/octene copolymers, and having a PRR between about 8 and 70, a melt strength of at least 5 cN, a density less than 0.91 g/cc, and a “0.1 radian per second, at 190° C., viscosity” of at least 200,000 poise; and
at least one polypropylene polymer selected from the group consisting of polypropylene homopolymers and propylene/alpha-olefin interpolymers, and wherein the weight ratio of ethylene/alpha-olefin copolymer to polypropylene polymer in the composition being from “greater than 50:less than 50” to 90:10, and
wherein the thermoplastic composition comprises a “190° C. shear thinning index (STI)” of 20 or more, and two of the three following heat related characteristics:
a) a 140° C. stress strain slope of 0.20 or more;
b) an upper service temperature (UST) of 115° C. or more; and
c) a 120° C. hot creep elongation at 8.7 psi of less than 100%, and
wherein the ethylene/alpha-olefin copolymer has T-type long chain branching.
32. The composition of claim 31 , wherein the ethylene/alpha-olefin copolymer is selected from ethylene/1-butene copolymers, or ethylene/1-octene copolymers.
33. A thermoplastic composition comprising the following:
at least one ethylene/alpha-olefin copolymer consisting of the following monomers: ethylene and an alpha-olefin; and wherein the ethylene/alpha-olefin copolymer has a PRR between about 8 and 70, a melt strength of at least 5 cN, a density less than 0.91 g/cc, and a “0.1 radian per second, at 190° C., viscosity” of at least 200,000 poise; and
at least one polypropylene polymer selected from the group consisting of polypropylene homopolymers and propylene/alpha-olefin interpolymers, and wherein the weight ratio of ethylene/alpha-olefin copolymer to polypropylene polymer in the composition being from “greater than 50:less than 50” to 90:10, and
wherein the thermoplastic composition comprises a “190° C. shear thinning index (STI)” of 20 or more, and two of the three following heat related characteristics:
a) a 140° C. stress strain slope of 0.20 or more;
b) an upper service temperature (UST) of 115° C. or more; and
c) a 120° C. hot creep elongation at 8.7 psi of less than 100%, and
wherein the ethylene/alpha-olefin copolymer has T-type long chain branching.
34. The composition of claim 33 , wherein the ethylene/alpha-olefin copolymer is selected from ethylene/1-butene copolymers, or ethylene/1-octene copolymers.