Polyolefin foams made with isopentane-based blowing agents
View Patent ↗A blowing agent blend for making polyolefin foams comprising isopentane and at least one co-blowing agent. The co-blowing agent is either a physical co-blowing agent having a boiling point less than 28° C., or a chemical co-blowing agent, or combinations thereof. The blowing agent blend comprises less than about 99 mol % isopentane.
1. A blowing agent blend for making polyolefin foams comprising isopentane and at least one co-blowing agent, the co-blowing agent being (i) a physical co-blowing agent having a boiling point less than 28° C., (ii) a chemical co-blowing agent, or (iii) combinations thereof, and
wherein the blowing agent blend comprises less than about 99 mol % isopentane, and wherein if one of the at least one co-blowing agent is a physical co-blowing agent being isobutane, the blowing agent blend comprises less than 70 mol % isobutane.
2. The blowing agent blend of claim 1 , wherein the polyolefin foam is dimensionally stable.
3. The blowing agent blend of claim 1 , wherein the co-blowing agent includes at least one physical co-blowing agent, the at least one physical co-blowing agent being methane, ethane, n-propane, n-butane, isobutane, cyclopropane, nitrogen, argon, carbon dioxide, sulfur hexafluoride, nitrous oxide, dimethyl ether, 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2-tetrafluoroet (HFC-134), 1,1,1,3,3-pentafluoropropane (HFC-245fa), or combinations thereof.
4. The blowing agent blend of claim 1 , wherein the blowing agent blend includes a chemical co-blowing agent.
5. The blowing agent blend of claim 1 , wherein the blowing agent blend comprises from about 10 mol % to about 60 mol % isopentane.
6. The blowing agent blend of claim 5 , wherein the blowing agent blend comprises from about 15 mol % to about 40 mol % isopentane.
7. The blowing agent blend of claim 6 , wherein the blowing agent blend comprises from about 25 mol % to about 40 mol % isopentane.
8. The blowing agent blend of claim 1 , wherein the polyolefin foam comprises polyethylene.
9. The blowing agent blend of claim 1 , wherein the polyolefin foam has a density of less than 3 lb/ft 3 .
10. A polyolefin foam structure prepared by the process comprising the acts of:
melting a thermoplastic polyolefin polymer;
dissolving an effective amount of a blowing agent blend in the polyolefin polymer, the blowing agent blend comprising isopentane and at least one co-blowing agent, the co-blowing agent being (i) a physical co-blowing agent having a boiling point less than 28° C., (ii) a chemical co-blowing agent, or (iii) combinations thereof, and wherein the blowing agent blend comprises less than about 99 mol % isopentane, and wherein if one of the at least one co-blowing agent is a physical co-blowing agent being isobutane, the blowing agent blend comprises less than 70 mol % isobutane;
forming an extrudate;
transferring the extrudate to an expansion zone; and
permitting the extrudate to expand in the expansion zone to produce the polyolefin foam structure, the polyolefin foam structure being a substantially closed-cell and dimensionally-stable structure.
11. The polyolefin foam structure of claim 10 , wherein the extrudate comprises from about 1 to about 18 wt % blowing agent.
12. The polyolefin foam structure of claim 10 , wherein the polyolefin foam structure has at least 20 cells per inch.
13. The polyolefin foam structure of claim 12 , wherein the polyolefin foam structure has at least 25 cells per inch.
14. The polyolefin foam structure of claim 13 , wherein the polyolefin foam structure has at least 30 cells per inch.
15. The polyolefin foam structure of claim 10 , wherein the polyolefin foam structure is a sheet.
16. The polyolefin foam structure of claim 10 , wherein the polyolefin foam structure is a plank.
17. The polyolefin foam structure of claim 10 further including mixing a nucleating agent and the thermoplastic polyolefin polymer to form a mixture, and dissolving an effective amount of the blowing agent blend into the mixture.
18. The polyolefin foam structure of claim 10 further including
melting a stability control agent,
mixing the stability control agent and the thermoplastic polyolefin polymer to form a mixture, and
dissolving an effective amount of the blowing agent blend into the mixture.
19. The polyolefin foam structure of claim 10 , wherein the polyolefin foam structure comprises polyethylene.
20. The polyolefin foam structure of claim 19 , wherein the polyolefin foam structure comprises low density polyethylene.
21. The polyolefin foam structure of claim 10 , wherein the polyolefin foam structure has a density of less than 3 lb/ft 3 .
22. A process for making a polyolefin foam structure comprising the acts of:
melting a thermoplastic polyolefin polymer;
dissolving an effective amount of a blowing agent blend in the polyolefin polymer, the blowing agent blend comprising isopentane and at least one co-blowing agent, the co-blowing agent being (i) a physical co-blowing agent having a boiling point less than 28° C., (ii) a chemical co-blowing agent, or (iii) combinations thereof, and wherein the blowing agent blend comprises less than about 99 mol % isopentane, and wherein if one of the at least one co-blowing agent is a physical co-blowing agent being isobutane, the blowing agent blend comprises less than 70 mol % isobutane;
forming an extrudate;
transferring the extrudate to an expansion zone; and
permitting the extrudate to expand in the expansion zone to produce the polyolefin foam structure.
23. The process of claim 22 , wherein the polyolefin structure is a substantially closed-cell and dimensionally stable structure.
24. The process of claim 22 , wherein the extrudate comprises from about 1 to about 18 wt % blowing agent.
25. The process of claim 22 further including mixing a nucleating agent and the thermoplastic polyolefin polymer to form a mixture, and dissolving an effective amount of the blowing agent blend into the mixture.
26. The process of claim 22 further including
melting a stability control agent,
mixing the stability control agent and the thermoplastic polyolefin polymer to form a mixture, and
dissolving an effective amount of the blowing agent blend into the mixture.
27. The process of claim 22 , wherein the co-blowing agent includes at least one physical co-blowing agent, the at least one physical co-blowing agent being methane, ethane, n-propane, n-butane, isobutane, cyclopropane, nitrogen, argon, carbon dioxide, sulfur hexafluoride, nitrous oxide, dimethyl ether, 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1,3,3-pentafluoropropane (HFC-245fa), or combinations thereof.
28. The process of claim 22 , wherein the blowing agent blend includes a chemical co-blowing agent.
29. The process of claim 22 , wherein the blowing agent blend comprises from about 10 mol % to about 60 mol % isopentane.
30. The process of claim 29 , wherein the blowing agent blend comprises from about 15 mol % to about 40 mol % isopentane.
31. The process of claim 30 , wherein the blowing agent blend comprises from about 25 mol % to about 40 mol % isopentane.
32. The process of claim 22 , wherein the polyolefin foam structure comprises polyethylene.
33. The process of claim 32 , wherein the polyolefin foam structure comprises low density polyethylene.
34. The process of claim 22 , wherein the polyolefin foam structure has a density of less than 3 lb/ft 3 .
35. A blowing agent blend for foaming low density polyethylene foam consisting essentially of from about 10 to about 99 mol % isopentane and at least one co-blowing agent, the co-blowing agent being (i) a physical co-blowing agent having a boiling point less than 28° C., (ii) a chemical co-blowing agent, or (iii) combinations thereof, and wherein if one of the at least one co-blowing agent is a physical co-blowing agent being isobutane, the blowing agent blend comprises less than 70 mol % isobutane.
36. The blowing agent blend of claim 35 , wherein the co-blowing agent includes at least one physical co-blowing agent, the at least one physical co-blowing agent being methane, ethane, n-propane, n-butane, isobutane, cyclopropane, nitrogen, argon, carbon dioxide, sulfur hexafluoride, nitrous oxide, dimethyl ether, 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1,3,3-pentafluoropropane (HFC-245fa), or combinations thereof.
37. The blowing agent blend of claim 35 , wherein the blowing agent blend comprises from about 10 mol % to about 60 mol % isopentane.
38. The blowing agent blend of claim 37 , wherein the blowing agent blend comprises from about 25 mol % to about 40 mol % isopentane.
39. A process for making a low density polyethylene foam structure prepared by the process comprising the acts of:
melting a low density polyethylene polymer;
dissolving an effective amount of a blowing agent blend in the low density polyethylene polymer, the blowing agent blend comprising from about 10 to about 99 mol % isopentane and at least one co-blowing agent, the co-blowing agent being (i) a physical co-blowing agent having a boiling point less than 28° C., (ii) a chemical co-blowing agent, or (iii) combinations thereof, and wherein if one of the at least one co-blowing agent is a physical co-blowing agent being isobutane, the blowing agent blend comprises less than 70 mol % isobutane;
forming an extrudate;
transferring the extrudate to an expansion zone; and
permitting the extrudate to expand in the expansion zone to produce the low density polyethylene structure.
40. The process of claim 39 further including
melting a stability control agent,
mixing a nucleating agent, the stability control agent and the thermoplastic polyolefin polymer to form a mixture, and
dissolving an effective amount of the blowing agent blend into the mixture.
41. The process of claim 40 , wherein the nucleating agent is talc, and the stability control agent is glycerol monostearate.
42. The process of claim 39 , wherein the co-blowing agent includes at least one physical co-blowing agent, the at least one physical co-blowing agent being methane, ethane, n-propane, n-butane, isobutane, cyclopropane, nitrogen, argon, carbon dioxide, sulfur hexafluoride, nitrous oxide, dimethyl ether, 1,1-difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1,3,3-pentafluoropropane (HFC-245fa), or combinations thereof.
43. The process of claim 39 , wherein the blowing agent blend includes a chemical co-blowing agent.
44. The process of claim 39 , wherein the blowing agent blend comprises from about 10 mol % to about 60 mol % isopentane.
45. The process of claim 44 , wherein the blowing agent blend comprises from about 25 mol % to about 40 mol % isopentane.
46. The process of claim 39 , wherein the low density polyethylene foam has a density of less than 3 lb/ft 3 .
47. The blowing agent blend of claim 1 , wherein the blowing agent blend comprises isopentane and isobutane, the blowing agent comprises less than 70 mol % isobutane.
48. The blowing agent blend of claim 47 , wherein the blowing agent blend further includes at least one additional co-blowing agent selected from the group consisting of methane, ethane, n-propane, cyclopropane, and n-butane.
49. The blowing agent blend of claim 1 , wherein the blowing agent blend comprises less than 99 mol % isopentane and (i) at least one physical co-blowing hydrocarbon agent having a boiling point less than 28° C. and the at least one physical co-blowing hydrocarbon agent not being isobutane, (ii) at least one physical non-hydrocarbon co-blowing agent having a boiling point less than 28° C., (iii) at least one chemical co-blowing agent, or (iv) combinations thereof.
50. The blowing agent blend of claim 49 , wherein the blowing agent blend comprises less than 99 mol % isopentane and at least one physical hydrocarbon co-blowing agent selected from the group consisting of methane, ethane, n-propane, cyclopropane, and n-butane.
51. The blowing agent blend of claim 1 , wherein the blowing agent blend comprises less than 99 mol % isopentane and at least one physical non-hydrocarbon co-blowing agent having a boiling point less than 28° C.
52. The process of claim 22 , wherein the blowing agent blend comprises isopentane and isobutane, the blowing agent comprises less than 70 mol % isobutane.
53. The process of claim 52 , wherein the blowing agent blend further includes at least one additional co-blowing agent selected from the group consisting of methane, ethane, n-propane, cyclopropane, and n-butane.
54. The process of claim 22 , wherein the blowing agent blend comprises less than 99 mol % isopentane and (i) at least one physical co-blowing hydrocarbon agent having a boiling point less than 28° C. and the at least one physical co-blowing hydrocarbon agent not being isobutane, (ii) at least one physical non-hydrocarbon co-blowing agent having a boiling point less than 28° C., (iii) at least one chemical co-blowing agent, or (iv) combinations thereof.
55. The process of claim 54 , wherein the blowing agent blend comprises less than 99 mol % isopentane and at least one physical hydrocarbon co-blowing agent selected from the group consisting of methane, ethane, n-propane, cyclopropane, and n-butane.
56. The process of claim 22 , wherein the blowing agent blend comprises less than 99 mol % isopentane and at least one physical non-hydrocarbon co-blowing agent having a boiling point less than 28° C.
57. A blowing agent blend for making polyolefin foams comprising (i) isopentane, (ii) isobutane, and (iii) at least one of the co-blowing agents selected from the group consisting of n-propane, 1,1,1,2-tetrafluoroethane (HFC-134a), dimethyl ether, ethane, butane, and combinations thereof, and wherein the blowing agent blend comprises less than 70 mol % isobutane.
58. The blowing agent blend of claim 57 , wherein the blowing agent blend consists essentially of (i) isopentane, (ii) isobutane, and (iii) at least one of the co-blowing agents selected from the group consisting of n-propane, 1,1,1,2-tetrafluoroethane (HFC-134a), dimethyl ether, and combinations thereof.
59. The blowing agent blend of claim 57 , wherein the blowing agent blend comprises at least 10 mol % isopentane.
60. A process for making a polyolefin foam structure comprising the acts of:
melting a thermoplastic polyolefin polymer;
dissolving an effective amount of a blowing agent blend in the polyolefin polymer, the blowing agent blend comprising (i) isopentane, (ii) isobutane, and (iii) at least one of the co-blowing agents selected from the group consisting of n-propane, 1,1,1,2-tetrafluoroethane (HFC-134a), dimethyl ether, ethane, butane, and combinations thereof, and wherein the blowing agent blend comprises less than 70 mol % isobutane;
forming an extrudate;
transferring the extrudate to an expansion zone; and
permitting the extrudate to expand in the expansion zone to produce the polyolefin foam structure.
61. The process of claim 60 , wherein the blowing agent blend consists essentially of (i) isopentane, (ii) isobutane, and (iii) at least one of the co-blowing agents selected from the group consisting of n-propane, 1,1,1,2-tetrafluoroethane (HFC-134a), dimethyl ether, and combinations thereof.
62. The process of claim 60 , wherein the blowing agent blend comprises at least 10 mol % isopentane.