GB253085A - Improvements in or relating to the electrical deposition of organic materials - Google Patents

Abstract

253,085. Kodak, Ltd., (Assignees of Sheppard, S. E., and Eberlin, L. W.). June 8, 1925, [Convention date]. Indiarubber. guttapercha. and balata, preparation of.-Rubber is deposited on to an anode from an aqueous emulsion thereof containing a reducing agent readily oxidizes to form a dye-stuff. Suitable reducing agents are the leuco bases of such vat dye-stuffs as indanthrone or a miwture of a paradiamine compound and a phenol or naphthol in which the para position is free. In an example the leuco base of trichloroindanthrone is added to the emulsion to the extent of one to two per cent of the rubber content. The coloured oxidation product is deposited with the rubber. In another example one per cent of a mixture of asymmetric-dimethyl-para-phenylenediamine and alpha-naphthol is added. Catalysers such as ceric or manganous salts may also be added. In an example a rubber dispersion is prepared by mixing 1000 c.c. of a 5 per cent solution of rubber in benzol with 1000 c.c. of paraffin and 500 c.c. of sulphonated castor oil and stirring the mixture into 3000 c.c. of an aqueous solution containing 150 gms of Castile soap as emulsifier. Aniline sulphate may be added before emulsification for the purposes of accelerating vulcanization. Vulcanizing agents may be added before emulsification or may be added to the emulsion in colloidal form, or may be omitted, vulcanization in this case being effected by subsequent treatment in a solution of sulphur in sulphur dichloride or otherwise. An ammonium soap is used as emulsifier when a coating of high electrical resistance is desired: the ammonia is driven off during vulcanization. The emulsifying agents may also consist of saturated or unsaturated compounds of fatty acids with alkali metals or ammonium, or of sodium phenol or cresolate with or without excess of cresol or cresylic acid. Direct current either constant or pulsating is employed. The voltage may be 110 and the current “ to ¢ amp. per sq. inch of an anode surface. According to the Specification as open to inspection under Sect. 91 (3) (a) sodium sulphite, thiosulphate or hydrosulphite, or hydroquinone, resorcin or phenolic amines may be used as reducing agents. This subject-matter does not appear in the Specification as accepted.