GB326497A - Improvements in or relating to the manufacture of goods of rubber or similar material - Google Patents

Abstract

326,497. Dunlop Rubber Co., Ltd., Chapman, W. H., and rounder, D. W. Nov. 14, 1928. Latex, coagulating; indiarubber &c. sheets, threads, tapes, and rods; attaching to other articles.-Relates to the manufacture of goods of rubber or similar material from aqueous emulsions or dispersions which are heat sensitive, i.e. stable in the cold but capable of being gelled rapidly by heat, by dipping, spreading, impregnating, spraying, moulding, extrusion or electrophoresis. According to the invention, goods are formed by the contacting of such heat sensitive dispersions with a fluid heating medium subsequent to the dispersions having been brought to the desired shape or lay out while still in the fluid state, and subsequent to the removal of the shaped fluids from the bulk of the dispersions. Dispersions which are not heat sensitive can be sensitized by the addition of gelling agents in insufficient quantity to bring about rapid gelling in the cold, or by the addition of substances which are inactive in the cold but. become active gelling agents upon the application of heat. Examples of sensitizers are ammonium persulphate, with or without trioxymethylene, and sodium silico fluoride. In examples :-(1) An unheated former is dipped into a heat sensitized mixing and on withdrawal is placed in an atmosphere of steam or in a bath of hot water whereby the deposit is gelled; the required thickness may be attained by repeated dippings: the deposit may be dried on the former or after stripping while in the wet state and is then vulcanized; wire can be covered with rubber by this method. (2) A film of sensitized latex mixing is spread on to a face sheeting and is passed into a heating fluid such as steam, hot air or hot water; the film may be dried on the sheeting or removed and dried. (3) Heat sensitized latex is caused to flow into hot water through a shaped die; tubes, sheeting, strips of various sections and tyre treads may be produced. Other examples are described. Specifications 219,635, 290,313. 302,201, 324,104 and 326,210 are referred to.