Foams produced under reduced pressure and method of preparing such foams
First Claim
1. A method for preparing an insulation foam wherein one or more polymeric foam forming materials are reacted under foam forming conditions and wherein cell voids are created in the foam during the reaction, the improvement comprising the steps of:
- causing the foam forming materials to react in an area to form cell voids;
maintaining a negative pressure condition in the area during the time the reaction is occurring; and
encasing the resultant polymeric foam in a gas impermeable material wherein the negative pressure in the cell voids is maintained.
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Accused Products
Abstract
Foams are prepared under reduced pressure and are subsequently encased in a material which will prevent ambient air from entering the cell voids. In the most preferred embodiment of the invention a polyurethane or polyisocyanurate foam is formed by mixing the polyol and isocyanate components under reduced pressure, allowing the gas within the foam to reach equilibrium at a lesser pressure then in prior systems. The need for blowing agents is substantially reduced and the K-factor of such foams is highly desirable. The foams are particularly well suited for use in refrigeration applications where the foams can be encased to prevent air from entering the cells after curing of the foam.
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Citations
11 Claims
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1. A method for preparing an insulation foam wherein one or more polymeric foam forming materials are reacted under foam forming conditions and wherein cell voids are created in the foam during the reaction, the improvement comprising the steps of:
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causing the foam forming materials to react in an area to form cell voids; maintaining a negative pressure condition in the area during the time the reaction is occurring; and encasing the resultant polymeric foam in a gas impermeable material wherein the negative pressure in the cell voids is maintained. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An insulating foam formed by the process which comprises reacting one or more polymeric foam forming materials under foam forming conditions to create a cured foam which includes cell voids and wherein the reaction takes place in an area in which a negative pressure exists during the time the reaction is occurring;
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wherein the foam includes a gas impermeable encasement surrounding the foam to prevent ambient gases from penetrating the polymeric foam and equalizing the pressure in the cell voids with the ambient pressure and wherein the negative pressure in the cell voids is maintained. - View Dependent Claims (8, 9, 10, 11)
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Specification