Process for preparing rigid polyisocyanurate foams using natural-oil polyols
View Patent ↗The present invention provides a process for producing a rigid polyisocyanurate foam involving reacting at an isocyanate index of from about 175 to about 400, a polyisocyanate with at least one natural-oil polyol containing at least about 35 wt. %, based on the weight of the polyol, of natural oil, having a hydroxyl number from about 175 to about 375 and a hydroxyl functionality of about 2.0 to about 2.8, in the presence of a blowing agent and optionally, in the presence of one or more of surfactants, flame retardants, pigments, catalysts and fillers, wherein the resulting foam has a renewable biobased content of at least 8% by weight. The foams provided by the inventive process possess properties similar to foams produced from petroleum-derived materials and may find use in wall or roof insulation systems. The high biobased content (>8%) may allow wall or roof insulation systems containing these foams to be considered for the U.S. Government's preferred procurement program.
1. A process for producing a rigid polyisocyanurate foam comprising reacting at an isocyanate index of from about 175 to about 400:
a polyisocyanate; with
at least one natural-oil polyol containing at least about 35 wt. %, based on the weight of the polyol, of soybean oil, having a hydroxyl number from 175 to 375, a hydroxyl functionality of about 2.0 to about 3.5 and a viscosity less than 2,000 centipoise at 25° C.;
in the presence of a blowing agent consisting of water and at least one compound selected from the group consisting of isomers of butane, isomers of pentane and isomers of hexane;
and optionally, in the presence of one or more of surfactants, flame retardants, pigments, catalysts and fillers
wherein the resulting foam has a renewable bio-based content of least 8% by weight.
2. The process according to claim 1 , wherein the polyisocyanate is selected from the group consisting of m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,6-hexamethylene diisocyanate, 1,4-hexamethylene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, hexahydro-toluene diisocyanate and its isomers, isophorone diisocyanate, dicyclohexylmethane diisocyanates, 1,5-naphthylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-biphenylene diisocyanate, 3,3′-dimethoxy-4,4′-biphenylene diisocyanate, 3,3′-dimethyl-diphenylpropane-4,4′-diisocyanate, 2,4,6-toluene triisocyanate, 4,4′-dimethyl-diphenylmethane-2,2′,5,5′-tetraisocyanate and polymeric diphenylmethane diisocyanate (PMDI).
3. The process according to claim 1 , wherein the polyisocyanate is polymeric diphenylmethane diisocyanate (PMDI).
4. The process according to claim 1 , wherein the at least one natural-oil polyol contains at least about 40 wt. %, based on the weight of the polyol, of soybean oil.
5. The process according to claim 1 , wherein the at least one natural-oil polyol contains at least about 45 wt. %, based on the weight of the polyol, of soybean oil.
6. The process according to claim 1 , wherein at the least one natural-oil polyol has a viscosity at 25° C. of less than about 1000 cps.
7. The process according to claim 1 , wherein the at least one natural-oil polyol has a viscosity at 25° C. of less than about 500 cps.
8. The process according to claim 1 , wherein the at least one natural-oil polyol has a viscosity at 25° C. of less than about 200 cps.
9. The process according to claim 1 , wherein the at least one natural-oil polyol has a hydroxyl number of about 200 to about 350 and a functionality of about 2.0 to about 2.5.
10. The process according to claim 1 , wherein the blowing agent consists of a mixture of water, cyclopentane and isopentane.
11. The process according to claim 1 , wherein the isocyanate index is from about 250 to about 350.
12. The process according to claim 1 , wherein the isocyanate index is from about 270 to about 310.
13. The process according to claim 1 , wherein said natural-oil polyol has a hydroxyl number of 175 to 375 and a functionality of about 2.0 to about 2.8.