Free-flowing polymer composition
The present invention relates to substantially free-flowing polymer particles. The polymer particles are those which have a one millimeter penetration temperature of less than about 75° C. as determined by thermal mechanical analysis or an unconfined yield strength of greater than about 15 pounds per square foot (73 kilograms per square meter). The composition also comprises an effective amount of an anti-blocking agent in the presence or absence of a binding agent.
1. A composition comprising:
polymer particles having
a one millimeter penetration temperature of less than 75° C. as determined
by thermal mechanical analysis; or
an unconfined yield strength of greater than 15 pounds per square foot (73 kilograms per square meter); or
both (1) and (2);
an effective amount of anti-blocking agent mechanically adhered to the polymer particles.
2. A composition comprising:
polymer particles having a one millimeter penetration temperature of less than 75° C. as determined by thermal mechanical analysis; and
from about 0.02 to about 3 weight percent of an anti-blocking agent mechanically adhered to the polymer particles.
3. A composition comprising:
(a) polymer particles having an unconfined yield strength of greater than 15 pounds per square foot; and
(b) from about 0.02 to about 3 weight percent of an anti-blocking agent mechanically adhered to the polymer particles.
4. The composition of claim 1 wherein the polymer is a polymer comprising polymer units derived from ethylene.
5. The composition of claim 4 which further comprises polymer units derived from a C 3 –C 8 alpha-olefin.
6. The composition of claim 5 wherein the alpha-olefin is selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene.
7. The composition of claim 4 which further comprises polymer units derived from vinyl acetates.
8. The composition of claim 1 wherein the polymer is a styrenic block copolymer.
9. The composition of claim 8 wherein the styrenic block copolymer is selected from the group consisting of styrene-butadiene copolymer and styrene-butadiene-styrene copolymer.
10. The composition of claim 1 wherein the polymer is a polyvinyl chloride polymer.
11. The composition of claim 1 wherein the polymer comprises polymer units derived from propylene.
12. The composition of claim 1 wherein the anti-blocking agent comprises from 0.02 to 3 weight percent anti-blocking agent based on the total composition.
13. The composition of claim 12 wherein the anti-blocking agent comprises from 0.08 to 1.5 weight percent anti-blocking agent based on the total composition.
14. The composition of claim 13 wherein the anti-blocking agent comprises from 0.1 to 0.5 weight percent anti-blocking agent based on the total composition.
15. The composition of claim 14 wherein the anti-blocking agent comprises from 0.15 to 0.3 weight percent anti-blocking agent based on the total composition.
16. The composition of claim 1 wherein the anti-blocking agent is selected from the group consisting of talc, mica, calcium carbonate, finely divided silica, fumed silica, organic acids, metal organic esters and powdered polymers.
17. The composition of claim 1 wherein the anti-blocking agent is talc.
18. The composition of claim 1 wherein the anti-blocking agent is calcium stearate.
19. The composition of claim 14 wherein the anti-blocking agent is talc.
20. The composition of claim 15 wherein the anti-blocking agent is talc.
21. The composition of claim 1 wherein the anti-blocking agent is mechanically adhered to the surface of at least about 50 percent of the polymer particles.
22. The composition of claim 21 wherein at least about 10 percent of the diameter of an individual anti-blocking agent is embedded into an individual polymer particle.
23. The composition of claim 21 wherein up to about 50 percent of the diameter of an individual anti-blocking agent is embedded into an individual polymer particle.
24. The composition of claim 1 wherein the unconfined yield strength of the composition is at least about 20 percent greater than the strength of the same composition without an anti-blocking agent.
25. The composition of claim 1 which further comprises up to 50 percent (by weight) of at least one other thermoplastic polymer.
26. The composition of claim 25 wherein the at least one other thermoplastic polymer is selected from the group consisting of homopolymers and copolymers of polystyrene, polyethylene and polypropylene.
27. The composition of claim 6 wherein the alpha-olefin is propylene.
28. The composition of claim 6 wherein the alpha-olefin is 1-butene.
29. The composition of claim 6 wherein the alpha-olefin is 1-hexene.
30. The composition of claim 6 wherein the alpha-olefin is 1-octene.
31. The composition of claim 1 wherein the polymer is an unvulcanized elastomer.
32. The composition of claim 1 wherein the polymer is EDDM.
33. The composition of claim 1 wherein the polymer is EBDM.
34. The composition of claim 1 wherein the polymer comprises a homopolymer of propylene.
35. The composition of claim 1 wherein the polymer comprises a copolymer of propylene.