Process for making integrated layered urethane products

Abstract

Polyurethane shapes containing a core layer of a water soluble polymer such as polyethylene oxide (PEO) are produced by casting onto a surface an aqueous mixture containing a pre-polymer of a hydrophilic polyurethane as a first layer of uncured polyurethane, covering the uncured first layer with release paper and compressing the layer, uncovering the uncured first layer and distributing PEO on the uncured surface, applying a second layer of uncured polyurethane on top of the PEO while the polyurethane is still uncured, then covering the resulting mass with release paper and compressing it to form an integrated, layered shaped article containing a core region enriched in PEO that when wetted releases PEO over an extended period. The second layer is applied by adhering about one-half of the first uncured foam layer to the release paper as the first uncured layer is uncovered and then recombining the adhered material on top of the PEO and further compressing the resulting mass to produce an integrated, layered shaped article. The second layer can be applied, alternatively, by independently casting a second layer of uncured polyurethane foam after distributing the PEO and then compressing and curing. The PEO containing shapes are useful in making improved comfort strips for wet shaving razors. Shape products of the process where the core region contains other specified working ingredients are useful in applications including bandages and wound dressings, cosmetic sponges, cleaning and polishing sponges, dry cleaning and anti-static sheets, and in household, industrial and environmental clean up and waste recovery.