Patent GB-408145-A (GB)
Title: Improvements in or relating to the production of rubber goods and apparatus therefor
IPC: C25D1/18
Filed: 1933-09-07
Abstract: 408,145. Electric endosmose. McKAY, R. F., Fort Dunlop, Birmingham.-(International Latex Processes, Ltd. ; 10, Lefebvre Street, St. Peter's Port, Guernsey.) Sept. 7, 1933, No. 24769. [Class 41.] Rubber goods, particularly those obtained from rubber dispersions are washed by passing water or an aqueous medium capable of removing water soluble substances through them by electro-osmosis. The aqueous medium may be an aqueous solution of electrolyte such as ammonia. The goods may be deposited on a former and washed while on it or removed and washed, and the film may be dried before washing. In an example a perforated metallic glove former (Fig. 4) is covered with a layer of a fmely divided filtering substance held together by a binder, then a renewable layer of whiting and finally a rubber layer by single dipping under vacuum. The rubber layer is dried and the former then immersed in an ammonia solution. The interior of the former is filled with the same solution, a vacuum applied through 4 and current allowed to pass, with the perforated former or the tube 4 as cathode, and the containing tank or an electrode therein as anode. The liquid passing through the rubber layer is exhausted via hole 13 through pipe 4. In another example an article is made by repeated dipping and used as a bag containing ammonia solution and a cathode, and is immersed in a chamber containing ammonia solution. In another example a non-porous metal former (Fig. 7) provided with apertures 20 is coated with a film of rubber by dipping. The top of the film is sealed by wrapping a band of fabric round it and by applying air pressure to the interior of the former the film is caused to balloon slightly away from the former. On the passage of current gas is evolved at the surface of the former and with the soaps and proteins washed out forms a foam 30 which passes through 20 into the interior of the former from which it may be removed as by siphoning. The top of the film may also be secured to the former by making the surface of that portion of the former of such material that the rubber strongly adheres thereto or as detailed in the example below. In a further example a glove formed of metal (Fig. 11) is provided with a perforated groove 39. In the groove is placed a screen 38 treated with coagulant and the glove dipped into latex. The film is caused to adhere at the top of the former by dipping the deposited film into a coagulant to a depth less than that of the film, thus leaving a narrow strip of rubber which on drying forms an adherent strip. The prior treatment of 38 with coagulant produces a thicker bead 40 of rubber. The washing is carried out as in the example above. The screen 38 or the groove 39 of Fig. 11 or the holes 20 of Fig. 7 may be temporarily sealed with water soluble material such as gelatine or molten cane sugar to prevent leakage of latex during dipping and before washing. Rubber-fabric goods and goods made of crude or reclaim rubbers as well as produced from latex may be treated according to the invention.