Rigid polyurethane foam and system and method for making the same
An embodiment of a closed-cell polymeric rigid foam may be made using a one-shot method and a reaction system that includes a hydrofluoroalkene physical blowing agent and a polyol mixture having an aminic polyol. The hydrofluoroalkene blowing agent has 3 to 5 carbon atoms and a boiling point between 10° C. and 40° C. at 1 atmosphere pressure. Embodiments of rigid foams may have high closed cell content and are particularly well suited for thermal insulation.
1. A process for preparing rigid polymeric foam having a closed cell content of greater than 85% and a density of less than 4.5 pounds per cubic foot, wherein the process comprises reacting:
(a) an isocyanate composition comprising one or more organic polyisocyanates; and
(b) an isocyanate reactive composition comprising:
(i) a first polyol, wherein the first polyol is a aminic polyol selected from the group consisting of aromatic amine-initiated polyols, Mannich polyols, and mixtures thereof; and
(ii) a second polyol having a nominal hydroxyl functionality of at least 2 and a molecular weight of from 60 to 10,000 that is different than the first polyol and is free of amine groups,
wherein either the isocyanate composition or the isocyanate reactive composition further comprises one or more alkane blowing agents and one or more hydrofluoroalkene blowing agents selected from the group consisting of 2-bromopentafluoropropene, 1-bromopentafluoropropene, 3-bromopentafluoropropene, 3,3,4,4,5,5,5-heptafluoro-1-pentene, 3-bromo -1,1,3,3-tetrafluoropropene, 2-bromo-1,3,3,3-tetrafluoropropene, 1-bromo-2,3,3,3-tetrafluoropropene, 1,1,2,3,3,4,4-heptafluorobut-1-ene, 2-bromo -3,3,3-trifluoropropene, E-1-bromo-3,3,3-trifluoropropene-1,3,3,3-trifluoro -2-(trifluoromethyl)propene, 1-chloro -3,3,3-trifluoropropene, 2-chloro -3,3,3-trifluoropropene, and 1,1,1-trifluoro-2-butene; and
wherein the weight ratio of the first polyol to the second polyol is from 40:60 to 25:75 and the combined weights of the first polyol and the second polyol is at least 20% of the total weight of the reaction system.
2. The process according claim 1 , wherein the alkane blowing agents comprise n-pentane, isopentane, cyclopentane, and combinations thereof.
3. The process of claim 2 , wherein the alkane blowing agents comprise isopentane, cyclopentane, and combinations thereof.
4. The process of claim 1 , wherein the second polyol comprises polyester groups.
5. The process of claim 1 , wherein the second polyol is a polyether polyol initiated with one or more glycols, glycerol, trimethylolpropane, sorbitorl, or sucrose.
6. The process according to claim 1 , wherein the combined weights of the first polyol and the second polyol is at least 25% of the total weight of the reaction system.
7. The process according to claim 1 , wherein the combined weights of the first polyol and the second polyol is at least 30% of the total weight of the reaction system.
8. The process according to claim 1 , wherein the weight ratio of the first polyol to the second polyol is from 40:60 to 30:70.
9. The process according to claim 8 , wherein the combined weights of the first polyol and the second polyol is at least 25% of the total weight of the reaction system.
10. The process according to claim 8 , wherein the combined weights of the first polyol and the second polyol is at least 30% of the total weight of the reaction system.
11. The process according to claim 1 , wherein a polyol blend comprises the first polyol and the second polyol and wherein the polyol blend has a OH value of 400 mg KOH/g.
12. The process according to claim 1 , wherein the aromatic amine-initiated polyol has a nominal hydroxyl functionality of at least 2 and a molecular weight of greater than 300 and less than 10,000.
13. The process according to claim 1 , wherein the Mannich polyol has a nominal hydroxyl functionality of at least 2, has a molecular weight of greater than 150 and less than 10,000, and contains at least one secondary or tertiary amine nitrogen atom.
14. The process of claim 1 , wherein the isocyanate reactive composition further comprises one or more chemical blowing agents.
15. The process according to claim 14 , wherein the one or more chemical blowing agents is water.
16. The process of claim 15 , wherein water is present at levels ranging from at least 0.2% and less than 5% by weight based on the total weight of components (a) and (b).
17. The process according to claim 1 , wherein the first polyol comprises an alkylene oxide moiety.
18. The process according to claim 17 , wherein the alkylene oxide moiety comprises ethylene oxide, propylene oxide, butylene oxide, or combinations thereof.
19. The process according to claim 17 , wherein the alkylene oxide moiety comprises ethylene oxide, propylene oxide, or combinations thereof.
20. The process according to claim 19 , wherein the alkylene oxide moiety comprises ethylene oxide.
21. A rigid polyurethane or polyisocyanurate foam having a closed cell content of greater than 85% and a density of less than 4.5 pounds per cubic foot, wherein the foam is the reaction product of:
(a) an organic polyisocyanate composition; and
(b) an isocyanate reactive composition comprising:
(i) a first polyol, wherein the first polyol is an aminic polyol selected from the group consisting of aromatic amine-initiated polyols, Mannich polyols, and mixtures thereof;
(ii) a second polyol having a nominal hydroxyl functionality of at least 2and a molecular weight of from 60 to 10,000 that is different than the first polyol and is free of amine groups; and
(iii) a blowing agent composition comprising one or more alkanes and one or more hydrofluoroalkene blowing agents selected from the group consisting of 2-bromopentafluoropropene, 1-bromopentafluoropropene, 3-bromopentafluoropropene, 3,3,4,4,5,5,5-heptafluoro-1-pentene, 3-bromo -1,1,3,3-tetrafluoropropene, 2-bromo -1,3,3,3-tetrafluoropropene, 1-bromo -2,3,3,3-tetrafluoropropene, 1,1,2,3,3,4,4-heptafluorobut-1-ene, 2-bromo-3,3,3-trifluoropropene, E-1-bromo-3,3,3 -trifluoropropene -1,3,3,3-trifluoro-2-(trifluoromethyl)propene, 1-chloro -3,3,3-trifluoropropene, 2-chloro -3,3,3-trifluoropropene, and 1,1,1-trifluoro-2-butene; and
wherein the weight ratio of the first polyol to the second polyol is from 40:60 to 25:75 and the combined weights of the first polyol and the second polyol is at least 20% of the total weight of the reaction system.
22. The rigid polyurethane or polyisocyanurate foam according to claim 21 , wherein the alkane comprises n-pentane, isopentane, cyclopentane, and combinations thereof.
23. The rigid polyurethane or polyisocyanurate foam according to claim 22 , wherein the alkane comprises isopentane, cyclopentane, and combinations thereof.
24. The rigid polyurethane or polyisocyanurate foam according to claim 21 , wherein the second polyol comprises polyester groups.
25. The rigid polyurethane or polyisocyanurate foam according to claim 21 , wherein the second polyol is a polyether polyol initiated with one or more glycols, glycerol, trimethylolpropane, sorbitorl, or sucrose.
26. The rigid polyurethane or polyisocyanurate foam according to claim 21 , wherein the combined weights of the first polyol and the second polyol is at least 25% of the total weight of the reaction system.
27. The rigid polyurethane or polyisocyanurate foam according to claim 21 , wherein the combined weights of the first polyol and the second polyol is at least 30% of the total weight of the reaction system.
28. The rigid polyurethane or polyisocyanurate foam according to claim 21 , wherein the weight ratio of the first polyol to the second polyol is from 40:60 to 30:70.
29. The rigid polyurethane or polyisocyanurate foam according to claim 28 , wherein the combined weights of the first polyol and the second polyol is at least 25% of the total weight of the reaction system.
30. The rigid polyurethane or polyisocyanurate foam according to claim 29 , wherein the combined weights of the first polyol and the second polyol is at least 30% of the total weight of the reaction system.
31. The rigid polyurethane or polyisocyanurate foam according to claim 21 , wherein the aromatic amine-initiated polyol has a nominal hydroxyl functionality of at least 2 and a molecular weight of greater than 300 and less than 10,000.
32. The rigid polyurethane or polyisocyanurate foam according to claim 21 , wherein the Mannich polyol has a nominal hydroxyl functionality of at least 2, has a molecular weight of greater than 150 and less than 10,000, and contains at least one secondary or tertiary amine nitrogen atom.
33. The rigid polyurethane or polyisocyanurate foam according to claim 21 , wherein the isocyanate reactive composition further comprises one or more chemical blowing agents.
34. The rigid polyurethane or polyisocyanurate foam according to claim 33 , wherein the one or more chemical blowing agents is water.
35. The rigid polyurethane or polyisocyanurate foam of claim 34 , wherein water is present at levels ranging from at least 0.2% and less than 5% by weight based on the total weight of components (a) and (b).
36. The rigid polyurethane or polyisocyanurate foam according to claim 21 , wherein a polyol blend comprises the first polyol and the second polyol and wherein the polyol blend has a OH value of 400 mg KOH/g.
37. The rigid polyurethane or polyisocyanurate foam according to claim 21 , wherein the first polyol comprises an alkylene oxide moiety.
38. The rigid polyurethane or polyisocyanurate foam according to claim 37 , wherein the alkylene oxide moiety comprises ethylene oxide, propylene oxide, butylene oxide, or combinations thereof.
39. The rigid polyurethane or polyisocyanurate foam according to claim 38 , wherein the alkylene oxide moiety comprises ethylene oxide, propylene oxide, or combinations thereof.
40. The rigid polyurethane or polyisocyanurate foam according to claim 39 , wherein the alkylene oxide moiety comprises ethylene oxide.