Novel process for making flexible polyurethane cellular products including a novel cell opening technique
AssigneeUnion Carbide Corporation
InventorKeith D. Cavender
Life of this patent
Estimating the term…
Abstract
A process for making molded flexible polyurethane cellular products which do not substantially shrink or change dimensionally upon cooling is provided by exposing the curing product to atmospheric pressure while in the confines of the mold. Exposure can be accomplished by unlatching the mold or opening a port at an appropriate time after the reaction mixture was introduced into the mold so as to burst the cell walls of the polyurethane product.
Claims18
A process for making molded high resilience polyurethane cellular products which do not substantially shrink or change dimensionally upon cooling comprising
- (a) introducing a liquid foamable polyurethane preaction mixture into a mold adapted to expose the curing product to atmospheric pressure during the curing of said product and said mold adapted to be closed,
- (b) closing said mold,
- (c) permitting said reaction mixture to expand into contact with the confines of the mold to form a curing molded polyurethane cellular product containing cells having cell walls of curing polyurethane and pressurized expansion gases contained within and supporting said cell walls,
- (d) exposing said curing product to atmospheric pressure while in contact with the confines of the mold at a time when said cell walls of said curing polyurethane cellular product have cured sufficiently to develop sufficient strength to avoid collapse of the cells of said product upon exposure to atmospheric pressure but before said cell walls have cured sufficiently to develop sufficient strength to resist bursting by the pressure of said expansion gases contained within said cell wall upon expose to atmospheric pressure,
- (e) allowing said curing polyurethane product to continue to cool and cure in said mold until it has developed sufficient strength to be removed from the mold without permanently distorting its shape, and
- (f) removing said product from said mold.
A process for making molded high resilience polyurethane cellular products which do not substantially shrink or change dimensionally upon cooling comprising:
- (a) introducing a liquid foamable polyurethane reaction mixture into a mold having means for closing said mold, and optionally having a closable port;
- (b) closing said mold,
- (c) permitting said reaction mixture to expand into contact with the confines of the mold to form a curing molded polyurethane cellular product containing cells having cell walls of curing polyurethane and pressurized expansion gases contained within and supporting said cell walls;
- (d) exposing said curing product to atmospheric pressure while in contact with the confines of the mold by either opening the mold or opening said port approximately 70 to 110 seconds after the reaction mixture was introduced into the mold;
- and
- (e) allowing said curing polyurethane product to continue to cool and cure in said mold until it has developed sufficient strength to be removed from the mold without permanently distorting its shape, and
- (f) removing said product from said mold.
Dependencies are inferred from the claim text.