Patent ID: 8541478

Claim:
A process for preparing a rigid polymeric foam having a closed cell content 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 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 90:10 to 40:60 and the combined weights of the first polyol and the second polyol is at least 30% of the total weight of the reaction system.