GB1051568A - - Google Patents

Abstract

1,051,568. Foam rubber articles. UNITED STATES RUBBER CO. May 4, 1965 [Jan. 5, 1965], No. 18638/65. Headings C3C, C3P and C3Q. An open-celled foam rubber article is prepared by introducing into a solution of an unsaturated hydrocarbon polymer rubber in an inert organic solvent a curvative system for the rubber, foaming the solution and allowing it to cure at least until the foam is self-supporting, freezing the foam, removing the solvent therefrom, and completing the cure of the foam. The curative system may operate at room temperature. The preferred system is a mono- or multicyclic dimethyol phenol curative for the polymer and a Lewis acid or sulphonic acid. The preferred phenolic curative is a halogen-containing dimethyol phenol, e.g. a bromomethyl alkylated phenol formaldehyde resin. The preferred Lewis acid is anhydrous stannic chloride. The preferred amount of phenolic curative is from 1% to 20% by weight and the preferred amount of Lewis acid is from 0.1 % to 8% by weight, both based on the weight of the polymer. The preferred rubbers are an ethylone-propylene-diene terpolymer, cis-polybut adiene, balata and butyl rubber. The preferred foaming method is by application of gas under pressure to the solution so that it is absorbed and subsequent expansion of the pressurized cement into a space at lower pressure, the solution preferably being agitated in contact with the pressurized gas.