Polymer foams containing blocking agents
AssigneeE. I. Du Pont de Nemours and Company
InventorsPhilip L. Bartlett, Joseph A. Creazzo, Howard S. Hammel
Life of this patent
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Abstract
An improved closed-cell polymer foam involves the use of a polyfluorocarbon forming agent (e.g., HCFC-22) in combination with an effective amount of a hydrogen bond forming blocking agent (e.g., organic ether, ester or ketone). The presence of the blocking agent is shown to significantly reduce the escape of blowing agent from and entry of air into the foam resulting in low thermal conductivity over a longer period of time and improved thermal insulation value.
Claims18
A method of manufacturing a closed cell foam comprising the steps of:
- (a) admixing an effective amount of a hydrogen-containing halocarbon blowing agent to the B-side component of a polyurethane or polyisocyanurate foam such as to hydrogen bond said halocarbon with a polyol in said B-side component, said halocarbon is selected from the group consisting of:
- CH.sub.2 F.sub.2 ;
- CHF.sub.2 CF.sub.3 ;
- CHF.sub.2 CHF.sub.2 ;
- CH.sub.2 FCF.sub.3 and mixtures thereof,
- (b) contacting said admixture of step (a) with an effective amount of an A-side component of a polyurethane or polyisocyanurate foam for sufficient time and temperature to produce foaming;
- and
- (c) recovering a fine closed-cell structured foam exhibiting improved k-factor relative to that predicted from VTC data.
A method of manufacturing a closed cell foam comprising the steps of:
- (a) admixing an effective amount of 1,1,1,2-tetrafluoroethane blowing agent to the B-side component of a polyurethane or polyisocyanurate foam such as to hydrogen bond said 1,1,1,2-tetrafluoroethane with the polyol in said B-side component;
- (b) contacting said admixture of step (a) with an effective amount of an A-side component of a polyurethane or polyisocyanurate foam for sufficient time and temperature to produce foaming;
- and
- (c) recovering a fine closed-cell structured foam exhibiting improved k-factor relative to that predicted from VTC data.
A closed-cell rigid polymer foam prepared from a foam-forming composition containing a physical blowing agent present from about 5 up to about 30 weight percent based on the total weight of the composition, and characterized in that the physical blowing agent comprises a hydrogen-bonding C.sub.1 -C.sub.2 polyfluorocarbon compound containing no chlorine or bromine atoms.
A process for producing a closed-cell rigid polyurethane or polyisocyanurate polymer foam containing within its cells a gas mixture comprising a hydrogen bonding C.sub.1 -C.sub.2 polyfluorocarbon compound containing no chlorine or bromine atoms characterized in that
- (a) an isocyanate-containing compound is mixed and allowed to react with an active hydrogen-containing compound in the presence of from about 5 to about 30 weight percent, based on combined weight of isocyanate-containing compound, of a physical blowing agent comprising the polyfluorocarbon compound.
A closed-cell rigid polymer foam prepared from a foam-forming composition containing a physical blowing agent present in up to about 20 weight percent based on the total weight of the composition, and characterized in that the physical blowing agent comprises a hydrogen-bonding C.sub.1 -C.sub.2 polyfluorocarbon compound containing no chlorine or bromine atoms.
Dependencies are inferred from the claim text.