Polyurethane foam composition

Abstract

Single component compositions for making a moisture-cured polyurethane foam are disclosed. Foam produced from the compositions of the present invention produce very low foaming pressure due to their 60-95 percent open-cell content. After these compositions are applied and cure, they form a permanent seal around the perimeter of installed fenestration products.

1. A single component polyurethane foam forming composition comprising a mixture of
 (a) prepolymers containing free isocyanate groups in the range of 12 to 17 percent by weight, based on the weight of the prepolymer, which is produced by reacting a polyisocyanate with a polyol blend comprising a first polyol that is a triol having a molecular weight of in the range of from 500 to 3000 600 to 2,500 and a second polyol that is a diol, triol or a mixture mixtures thereof having a molecular weight in the range of from 4,000 to 12,000 6,000 to 10,000, wherein the first to polyol and the second polyol are present in a parts by weight ratio in the range of form from 1.6 to 1:2; 
 (b) a blowing agent; and 
 (c) from 0.5 to 4 percent by weight a surfactant comprising the reaction product of a poly(alkyl siloxane) and a poly(alkylene oxide) copolymer, where the alkylene oxide are ethylene oxide, propylene oxide or butylene oxide, based on the total weight of the single component polyurethane foam forming composition, wherein said polyurethane foam forming composition forms an open-cell structure foam having open cells in the range of from 60% to 95%. 
 
     
     
       2. The composition of  claim 1  further comprising from 0.5 to 4 percent by weight, based on the total weight of the composition, of a polydimethyl siloxane polyoxyalkylene copolymer surfactant. 
     
     
       3. The composition of claim  2  1 wherein the surfactant comprises 1 to 3 percent by weight of the composition. 
     
     
       4. The composition of claim  2  1 wherein the surfactant has a molecular weight of less than 30,000. 
     
     
       5. The composition according to  claim 1 , wherein the polyisocyanate is selected from the group consisting of aliphatic, cycloaliphatic, aryliphatic, and aromatic polyisocyanates. 
     
     
       6. The composition according to  claim 5 , wherein the polyisocyanate is an aromatic polyisocyanate selected from a diphenylmethane diisocyanate, polyphenyl polymethylene isocyanate or a combination thereof. 
     
     
       7. The composition of  claim 1  wherein the blowing agent is a hydrocarbon, a fluorocarbon, a chlorocarbon, a chlorofluorocarbon or a mixture thereof. 
     
     
       8. The composition of  claim 7  wherein the blowing agent is a hydrocarbon selected from isobutane, propane, dimethylether or a mixture thereof. 
     
     
       9. The composition of  claim 1  wherein the composition contains additional auxiliary agent selected from amine catalysis catalysts, tin catalyst catalysts or flame retardants. 
     
     
       10. The composition of  claim 1 , wherein the triols and diols together comprise a secondary hydroxyl functionality of at least about 50 percent. 
     
     
       11. The composition of  claim 4  wherein the second polyol is a diol. 
     
     
       12. The composition of  claim 4  wherein the second polyol is a triol. 
     
     
       13. A moisture-cured polyurethane foam prepared from a composition of any one of claims claim  1 . 
     
     
       14. A The foam of  claim 13  wherein the foam has an open cell structure of from 60 to 95 percent open cells. 
     
     
       15. A method for the production of a polyurethane foam comprising supplying to a valved vessel a mixture comprising an isocyanate-terminated prepolymer and a blowing agent wherein the prepolymer is obtained by reacting a polyisocyanate with a polyol mixture comprising a first polyol that is a triol having a molecular weight from 500 to 3,000, and a second polyol that is a diol, triol or mixture thereof having a molecular weight from 4000 to 12,000, wherein the first and second polyols are present in a parts by weight ratio of from 1:6 to 1:2, allowing the mixture to reach equilibrium, adding pressure if needed, maintaining the pressure during storage and releasing the mixture outside the vessel to produce a foam which as a cell structure of from 60 to 95 percent open cells. 
     
     
       16. The method of  claim 15  wherein the mixture is dispensed from the vessel using a gun-like dispenser with or without a straw extender tip or with a trigger-straw dispenser. 
     
     
       17. A fenestration assembly comprising the polyurethane foam of  claim 13  applied and cured around the perimeter of an installed fenestration product. 
     
     
       18. Building materials comprising the polyurethane foam of  claim 14 . 
     
     
       19. A transportation craft comprising the foam of claim  13  14.