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AssigneeGeneral Electric Company
InventorsWilliam J. Ward, III, James Day, Monica A. Ferrero-Heredia, Edward J. McInerney
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Polyurethane foam of low thermal conductivity is prepared by employing carbon dioxide as a blowing agent, preferably in combination with a halogenated compound, typically a halocarbon or halohydrocarbon such as monofluorotrichloromethane or 1,1-dichloro-1-fluoroethane, and incorporating in the foam a carbon dioxide-reactive reagent. Sodium hydroxide and soda lime are illustrative carbon dioxide-reactive reagents. The carbon dioxide is preferably formed in situ by the reaction of water with the diisocyanate precursor of the polyurethane, and the carbon dioxide-reactivereagent is preferably introduced in admixture with a portion of the polyol precursor.
A polyurethane foam of low thermal conductivity having incorporated therein at least one of:
Dependencies are inferred from the claim text.
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Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof: use of inorganic compounding ingredients
Halogen containing compounds: containing carbon, halogen and hydrogen only
Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers: polyurethanes
Working-up
Term ended 29 Mar 2013 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
This invention relates to insulating foams, and more particularly to polyurethane foams having unusually low thermal conductivity.
Insulating polyurethane foam is an indispensable constituent of many refrigerators and similar cooling units. By reason of increasingly strict Federal Government energy conservation standards, it is of interest to develop foams having substantially lower thermal conductivity than those presently available.
Conventional insulating polyurethane foam is generally prepared by the reaction of at least one polyol with at least one diisocyanate in the presence of suitable catalysts, surfactants and blowing agents. Among the blowing agents employed are halogenated compounds, which may be halocarbons such as monofluorotrichloromethane and/or halohydrocarbons such as 1,1-dichloro-1-fluoroethane. They remain in the cell voids of the foam after blowing, and their presence therein is beneficial since they have very low thermal conductivity and thus contribute to the insulating quality of the foam.
The invention is illustrated by a series of examples in which a masterbatch was prepared from 68.54 parts (by weight) poly(oxyalkylene) polyol blend, 1.37 parts of cyclohexyldimethylamine, 0.15 part of dibutyltin dilaurate, 0.34 part of a silicone surfactant and 0.6 part of water. The masterbatch was whipped for about 10 seconds to disperse air bubbles as nucleation sites. Sodium hydroxide or soda lime was added in various proportions and the masterbatch was then blended with a mixture of 82.9 parts of toluene diisocyanate and 29 parts of monofluorotrichloromethane. The resulting mixture was whipped and foamed in a mold.
It was found that a loading of 3 times the stoichiometric amount of sodium hydroxide granules (maximum size 2 mm.) resulted in removal of 100% of the carbon dioxide in 60 days. A loading of sodium hydroxide powder at 1.5 times the stoichiometric amount removed about 75% of the carbon dioxide in 40 days; the same was true of a loading of soda lime in the stoichiometric amount.