GB679764A - Improvements in or relating to cellulose derivative emulsions - Google Patents

Abstract

A water-insoluble cellulose ester or ether is formed into an emulsion by adding it in a dry solid condition, preferably in p chips, shreds, or powder form, to a previously made "water-in-oil" type of emulsion, the continuous phase being formed by an organic solvent for the cellulose derivative or a mixture of solvents, with or without plasticizers, the solvents and plasticizers being insoluble or only sparingly soluble in water, and then effecting colloiding, dissolving, and emulsifying of the cellulose derivative in one operation by simple stirring. If desired, the plasticizers may be added to the emulsion subsequently to dissolving and emulsifying the cellulose derivative. The cellulose derivative may be cellulose acetate, propionate, butyrate, stearate, palmitate, or laurate, or it may be ethyl, propyl, butyl, benzyl, hexyl, or ethyl-hexyl cellulose ether. The plasticizer may be tricresyl phosphate, acetophenone, or benzophenone. In an example, nonaethylene glycol oleate is dissolved in water and then a mixture of benzyl alcohol and methylene chloride is added and mixed to form an emulsion. Shredded cellulose acetate film scrap is then mixed with the emulsion. A stable emulsion is formed. If diluted to 1 per cent concentration of cellulose acetate by addition of water it may be changed from a water-in-oil type of emulsion to an oil-in-water type by adding a sulphonated fatty alcohol. In another example gelatine is used as emulsifier. The gelatine is dissolved in water and an emulsion is made by adding a mixture of methylene chloride and benzyl alcohol and stirring. Shredded cellulose acetate is added, and stirring is continued till an emulsion of the cellulose acetate is obtained. An emulsion in the form of a thick cream is obtained. Silver bromide and other light-sensitive salts may be incorporated in the production of a photographic emulsion. The emulsion may be used in the production of films. Instead of gelatine, gums or alginates may be used. In another example, nonaethylene glycol oleate and a sulphonated fatty alcohol are dissolved in water rendered alkaline with potassium carbonate. The solution is poured into a mixture of methylene chloride, benzyl alcohol and benzophenone, and the mixture is stirred until an emulsion is formed. Shredded cellulose acetate is added and stirring is continued till the cellulose acetate is dissolved and emulsified. A creamy emulsion is obtained. Emulsions in acid, neutral, or alkaline condition may be obtained. They may be applied to paper, cloth, leather, rope, walls or floors, by dipping, rubbing, spreading by knife or roller or by other methods.