Viscoelastic foam with slow recovery time
AssigneesDow Global Technologies LLC, Rohm and Haas Company
InventorsKaoru Aou, William A. Koonce, Qinghao Meng, Christopher Thiede, William Griffith, Jr.
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Abstract
Recovery times of flexible polyurethane foams are increased by treatment with a pressure sensitive adhesive. An emulsion or dispersion of the adhesive in an aqueous carrier liquid is impregnated into the foam, with subsequent removal of the carrier. This invention is of special interest when the glass transition temperature of the starting foam is 16° C. or lower.
Claims15
A viscoelastic foam comprising a) an open-celled flexible polyurethane foam having internal surfaces coated with b) a pressure sensitive adhesive having a glass transition temperature of at most 0° C., wherein the pressure sensitive adhesive constitutes 1.5 to 35% of the combined weights of a) and b).
The viscoelastic foam of claim 4 wherein the open-celled flexible polyurethane foam has an airflow of at least 0.944 L/s, a density of 32 to 64 kg/m3 and a resilience of no more than 20%.
A method of reducing the recovery time of an open-celled polyurethane foam, comprising
- (1) impregnating a starting flexible polyurethane foam with a solution or emulsion of a pressure sensitive adhesive in a liquid carrier, the pressure sensitive adhesive having a glass transition temperature of no greater than 0° C., to wet internal surfaces of the foam and form an impregnated foam, and
- (2) removing the liquid carrier from the impregnated foam to produce a coated foam having a coating of the pressure sensitive adhesive on the internal surfaces of the flexible polyurethane foam.
Dependencies are inferred from the claim text.