process for the production of goods from schwammkautschuk from verschaeumten waessrigen kautschukdispersionen

摘要

Goods of sponge-like or cellular structure are made from foamed aqueous dispersions of rubber or the like containing an oxide of lower solubility of a metal of fixed valency of Group II of the Periodic Scheme, e.g. oxide of calcium, magnesium or zinc, by bringing about the solidification of the foam in the presence of aqueous solutions of ammonium salts conditioned to have a pH greater than 7. Suitable ammonium salts are ammonium sulphate, nitrate and acetate. Usually it is sufficient to make the solution of the ammonium salts just alkaline to give an alkaline reaction with such an indicator as Bromo-Thymol Blue. When heat is used to effect the solidification it should not be above the boiling point of water. Specifications 219,635, 290,313, 292,964, [all in Class 70], and 426,226 are referred to.