OPEN-PORE MOLDED ARTICLE ON POLYVINYL ACETALS, AND A PROCESS FOR ITS PREPARATION

摘要

of the disclosure When polyvinyl alcohol and vinyl acetate/ethylene copolymers are acetalized in an acid aqueous medium in the presence of a wetting agent, an open-pore solid foam is formed, if the reaction mixture contains gas bubbles. These gas bubbles are produced, in particular, by stirring in air. The molded articles obtained are porous, and the pores are uniformly distributed. The dried molded article absorbs many times its weight of water. It is employed as a sponge for household use and in industry.