AZEOTROPICALLY-MODIFIED BLOWING AGENTS FOR FORMING FOAMS
The present disclosure relates to improving insulation properties of foams by employing an azeotropically-modified blowing agent that preserves or improves R-value at various temperatures such as lower than ambient temperatures (below 24° C.). The present disclosure also provides foams with improved long-term thermal resistance (LTTR).
1 - 20 . (canceled)
21 . A foam composition formed from a foam precursor, the foam precursor comprising:
(a) an A-side comprising at least one organic isocyanate; and
(b) a B-side comprising:
(1) a blowing agent composition comprising:
(A) 80 to 95 wt. %, based on the total weight of the blowing agent composition, of at least one blowing agent selected from hydrofluorocarbons, hydrofluoroolefins, hydrochlorofluorocarbons, hydrofluoroethers, n-pentane, isopentane, and cyclopentane; and
(B) 5 to 20 wt %, based on the total weight of the blowing agent composition, of at least one azeotropic-modifier selected from methanol, ethanol, isopropanol, ethyl formate, methyl formate, diethyl ether, methyl propyl ether, methylal, acetone, and acetonitrile;
(2) a polyol for reacting with the at least one organic isocyanate;
(3) a catalyst for catalyzing the formation of the foam composition from the foam precursor;
(4) a flame retardant; and
(5) a surfactant;
wherein the foam composition comprises less than 1 wt. % of the azeotropic-modifier.
22 . The foam composition of claim 21 further comprising 0.1 to 10 wt. %, based on the amount of blowing agent composition, of water.
23 . The foam composition of claim 21 wherein the blowing agent is selected from at least one of n-pentane, isopentane, and cyclopentane, and the azeotropic-modifier is selected from at least one of methanol, ethanol, isopropanol, ethyl formate, methyl formate, diethyl ether, methyl propyl ether, methylal, acetone, and acetonitrile.
24 . The foam composition of claim 21 wherein the blowing agent is selected from at least one of n-pentane, isopentane, and cyclopentane, and the azeotropic-modifier is selected from at least one of methanol, ethanol, methylal, and methyl formate.
25 . The foam composition of claim 21 wherein the blowing agent is selected from at least one of n-pentane, isopentane, and cyclopentane, and the azeotropic-modifier is methyl formate.
26 . The foam composition of claim 21 wherein the blowing agent is selected from at least one of hydrofluorocarbons, hydrofluoroolefins, hydrochlorofluorocarbons, and hydrofluoroethers, and the azeotropic-modifier is selected from at least one of methanol, ethanol, isopropanol, ethyl formate, methyl formate, diethyl ether, methyl propyl ether, methylal, acetone, and acetonitrile.
27 . The foam composition of claim 21 wherein the blowing agent is selected from at least one of hydrofluorocarbons, hydrofluoroolefins, hydrochlorofluorocarbons, and hydrofluoroethers, and the azeotropic-modifier is selected from at least one of methanol, ethanol, methylal, and methyl formate.
28 . The foam composition of claim 21 wherein the at least one azeotropic-modifier is 0.5 to 3 wt. % of the B-side.
29 . The foam composition of claim 21 wherein the polyol is an aromatic polyester polyol.
30 . The foam composition of claim 21 wherein the foam composition is a rigid foam having a density of at least 1.5 lb./ft. 3 .
31 . The foam composition of claim 30 having an R-value measured according to ASTM C518 at less than 4.5° C. greater than that of a corresponding foam composition that is free of the at least one azeotropic-modifier.
32 . The foam composition of claim 30 having an R-value measured according to ASTM C518 at less than 4.5° C. of greater than 6 ft 2 .hr.° F./Btu.inch.