GB320387A - Method for the production of articles substantially made of organic materials from aqueous dispersions containing the said organic materials - Google Patents

Abstract

320,387. Dunlop Rubber Co., Ltd., Trobridge, G. W., and Murphy, E. A. April 12, 1928. Right to Grant relinquished. Moulding by dipping; moulding indiarubber, resins, or other organic materials. - Shaped articles are formed from aqueous dispersion of organic materials, particularly rubber, by repeated dipping, spreading, or pouring operations to form more than one substantially adhering fluid layer upon non-porous, chemically inactive deposition strata and effecting the setting and drying of each fluid layer by heat applied to that side of the fluid adjacent to the deposition strata prior to the deposition of the next fluid layer. For example, a hollow, non-porous former of glass, glazed porcelain, ebonite, zinc, aluminium, &c. is dipped into the dispersion and, upon removal, is immediately inverted to avoid formation of a drop and then re-inverted. The layer is then dried by circulating a hot fluid, e.g. water, oil, air, or steam through the former, after which the former is allowed to cool or is artificially cooled and the process repeated. The rate of drying is controlled by suitably adjusting the temperature and humidity of the air surrounding the former. In a modification, the layer is deposited upon the interior of non-porous moulds. Successive dippings may be in different dispersions to obtain glazed or multi-coloured effects. compound dispersions as described in Specification 290,313 may be employed; also dispersions of casein, albumen, cellulose esters, natural or artificial resin, &c., alone or admixed. A bottle teat is produced from an ammonia preserved rubber latex concentrated to contain 60 grams total solids and 0.03 grams ammonia per 100 ccs.; the composition of the dry mixing being rubber latex 100 parts by weight, sulphur 2, parts, transformer oil 5 parts and zinc diethyldithiocarbamate 1 part. A hollow glass former is employed and ten layers are deposited, drying being effected at 95-100‹ C. by hot water. The deposit is rolled to form the teat base and cured by immersion in boiling water for one hour. Specification 303,546 also is referred to.