Patent GB-552011-A (GB)
Title: Improvements in or relating to aqueous dispersions
IPC: C09D101/08
Filed: 1941-06-16
Abstract: 552,011. Emulsions. TATTERSALL, H. J., MUNRO, J., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. June 16, 1941, No. 7604. [Class 1 (i)] [Also in Group IV] In a coating composition of the kind comprising a dispersion in an aqueous medium of a liquid with or without a solid, the dispersed phase consisting of or comprising a film forming ingredient, the dispersing agent comprises a water soluble salt of an alkali metal or non- metallic base on the one hand, and, on the other hand, a polyvinyl ester of a polycarboxylic acid, the acid being only partially esterified so that it contains free carboxyl groups capable of the desired salt formation. The polycarboxylic acid from which the ester salt is derived may be phthalic acid or an aliphatic polycarboxylic acid. The ester salts may contain also ester groups derived from a monocarboxylic acid, and the base from which the salt is prepared may be sodium, potassium, ammonium or mono-di-tri- or tetramethyl ammonium hydroxide. The ester salts may be obtained by at least partial replacement in polyvinyl vinyl esters of monocarboxylic acids of the monocarboxylic acid groups, in an ester interchange reaction, by polycarboxylic acid groups, whereby products having free carboxyl groups are formed, e.g. a polyvinyl ester of a volatile monocarboxylic acid, e.g. polyvinyl acetate, may be heated in a melt with a polycarboxylic acid, or with the anhydride thereof in the presence of water, e.g. with phthalic, maleic, or succinic acids or their anhydrides, or with malic, citric, tartaric, adipic, sebacic, oxalic, or glutaric acid, the product being subsequently converted into a salt. Alternatively the ester salts may be produced by direct partial esterification of a polycarboxylic acid or anhydride thereof with polyvinvyl alcohol. The dispersed liquid phase may consist of a liquid film forming ingredient such as a drying-oil, or it may consist of a solution, in an organic solvent of a solid film forming ingredient such as a cellulose derivative or a natural or synthetic resin. Organic solvents, softeners, diluents and pigments and other insoluble effect materials which are commonly used in compositions containing such film forming ingredients may be included in the compositions. In making the dispersions, the polyvinyl ester salt and the organic film forming ingredient may be dissolved in an organic solvent comprising at least a proportion of a water miscible organic solvent or diluent, and water worked into the mixture until there is obtained a dispersion in which the water constitutes the disperse phase. Alternatively, a composition comprising the film forming ingredient may be worked with an aqueous solution of the ester salt; the solution of the ester salt may be worked wih a non-aqueous liquid phase containing the film forming ingredient, with or without a plasticizer and/or a volatile organic solvent until the water has been dispersed in the non-aqueous phase, further quantities of water being then worked in until phase inversion occurs. In examples, compositions are prepared from sodium polyvinyl acetate-phthalate and (1 to 8) wet nitro cellulose, (9) linseed oil, (10) a linseed oil-tung oil modified glycerol phthalate resin and (10) a urea-formaldehyde-castor oilmodified glycerol phthalate resin. In examples 1 to 8, the sodium polyvinyl acetate-phthalate may be replaced by sodium polyvinyl acetatemaleate or sodium polyvinyl acetate-citrate. Specification 344,401 is referred to.