Improvements in or relating to the production of foamed plastic materials

Abstract

Abstract Foamed polymers are prepared by beating an aqueous solution or dispersion of the polymer into a foam, causing the foam to set, and drying it, there being incorporated with the polymer foam a support foam produced by mixing the polymer solution or dispersion before completion of the foaming with an aqueous sol capable of forming an irreversible gel within a predetermined period by the action of a delayed action gelling agent which is also incorporated in the mixture before the gel is set, and causing the support to form a gel. Specified polymers are polyvinyl chloride, which may be plasticized with a butadiene-acrylonitrile copolymer, polyvinyl acetate, polystyrene, phenol-aldehyde resins, alkyd and polyester resins. Support foams may comprise proteins such as gelatin and water-soluble alginates which may be gelled with aldehydes, silica sols gelling by alternation of pH, water-soluble urea-formaldehydes gelling with acids, e.g. phosphoric or oxalic, and polyvinyl alcohol solutions. The support may or may not be removed from the foam after drying.

Inventors

• 👤 Alfred Cooper
• 👤 Felix Franks

Bibliographic Details