Propylene-based elastomers and uses thereof
The present invention provides curable and cured propylene-based elastomers, optionally including a diene, and having isotactic polypropylene crystallinity, a melting point by DSC equal to or less than 110° C., and a heat of fusion of from 5 J/g to 50 J/g. The present invention also provides blend compositions comprising any of the propylene-based elastomers described herein. The present invention also provides compositions comprising any of the propylene-based elastomers described herein and 1 to 100 parts by weight of inorganic filler per 100 parts of polymer. The present invention also provides films, fibers, fabrics, molded objects, and extruded forms which include any of the inventive compositions described herein.
1. An elastomer comprising:
(a) propylene-derived units in an amount of from 80 to 90 wt %, based on the combined weight of components (a), (b), and (c);
(b) diene-derived units in an amount within the range of from 0.3 to 3 wt %, based on the combined weight of components (a), (b), and (c); and
(c) ethylene-derived units in an amount of from 10 to 20 wt %, based on the combined weight of components (a), (b), and (c);
wherein the elastomer has isotactic polypropylene crystallinity, a melting point by DSC of from 0 to 110° C., and a heat of fusion of from 5 J/g to 50 J/g, and wherein the elastomer is partially insoluble and the fractions soluble at 23° C. and 31° C., as measured by the extraction method described herein, have ethylene contents differing by 5 wt % or less.
2. The elastomer of claim 1 , wherein the diene is 5-ethylidene-2-norbornene.
3. The elastomer of claim 2 , wherein the diene-derived units are present in an amount within the range of from 1 to 3 wt %, based on the combined weight of components (a), (b), and (c).
4. The elastomer of claim 1 , wherein the diene is 5-vinyl-2-norbornene.
5. The elastomer of claim 4 , wherein the diene-derived units are present in an amount within the range of from 0.5 to 1.5 wt %, based on the combined weight of components (a), (b), and (c).
6. The elastomer of claim 1 , wherein the elastomer has a Mooney viscosity ML(1+4) at 125° C. of from 0.5 to 100.
7. The elastomer of claim 1 , wherein the elastomer has a Mooney viscosity ML(1+4) at 125° C. of from 5 to 40.
8. The elastomer of claim 1 , wherein the elastomer is partially insoluble and the fractions soluble at 23° C. and 31° C., as measured by the extraction method described herein, have ethylene contents differing by 2 wt % or less.
9. The elastomer of claim 1 , wherein the elastomer has an isotactic propylene triad tacticity of from 65 to 95%.
10. The elastomer of claim 1 , wherein the elastomer has an m/r ratio of from 6 to 8.
11. The elastomer of claim 1 , wherein the elastomer has an isotacticity index of from 40 to 55.
12. A curable composition comprising the elastomer of claim 1 and a curing package.
13. The curable composition of claim 12 , further comprising an extender oil in an amount of 10 wt % or less, based on the total weight of the composition.
14. The curable composition of claim 12 , further comprising an extender oil in an amount of 1 wt % or less, based on the total weight of the composition.
15. The curable composition of claim 12 , wherein the composition does not contain an extender oil.