Blowing agents for polyurethane foam
AssigneePMC, Inc.
InventorsHerman Stone, Steve Lichvar, Charles W. Bredbenner, Richard Rupp, Elmer Minnich
Life of this patent
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Abstract
Improved methods are provided for incorporating carbon dioxide and carbon dioxide generating compounds into polyurethane foam forming compositions as blowing agents to eliminate or reduce the amount of low boiling liquid auxiliary blowing agents, such as methylene chloride and chlorofluorocarbons conventionally used in the manufacture of urethane foams.
Claims36
In the method for the continuous manufacture of flexible free rise polyurethane foam from reactants comprising at least one polyol and at least one reactive isocyanate where the reaction mixture includes water as a blowing agent and CO.sub.2 is incorporated into one of the liquid reactants, or into a blend of one or more of the liquid reactants, and the reactants are introduced under pressure through feed lines into a conventional mixer through two or more feed streams, and the reacting mixture is discharged from the mixer, the improvement which comprises:
- injecting gaseous CO.sub.2 under pressure into the feed stream of one or more of the liquid reactants of the foam forming composition at a distance from the mixer which will maximize the dissolution of CO.sub.2 in the feed stream.
The method of claim l,.where the CO.sub.2 is introduced into the isocyanate reactant feedstream.
In the method for the continuous manufacture of flexible polyurethane foam in conventional apparatus from the reaction of at least one polyol with at least one isocyanate where the reaction includes water as a blowing agent and CO.sub.2 is incorporated into the polyol containing liquid component and the polyol and isocyanate reactants are introduced into a mixer as separate feedstreams and the reacting mixture is discharged from the mixer, the improvement which comprises
- injecting CO.sub.2 under pressure into the polyol feedstream and the isocyanate feedstream at a distance that will maximize the dissolution of the CO.sub.2 in the polyol and isocyanate.
In the method for the continuous manufacture of polyurethane foam from reactants comprising at least one polyol and at least one isocyanate where the reaction mixture includes water as a blowing agent and CO.sub.2 is incorporated into at least one of the liquid reactants, the improvement which comprises adding CO.sub.2 as a supercritical fluid constituent to one or more of the liquid reactants comprising polyol and isocyanate which are maintained at a temperature of at least 88.degree. F., at a pressure of at least 1073 psi, and mixing the liquid reactants, and discharging the mixed foam-forming reactants at atmospheric pressure.
Dependencies are inferred from the claim text.