GB312061A - Improvement in non-caking pigmented coating compositions and processes of making same - Google Patents

Abstract

312,061. Du Pont de Nemours & Co., E. I., (Assignees of Coolidge, C., and Holt, H. S.). May 18, 1928, [Convention date]. Pigments for incorporating in various types of substantially non-aqueous lacquers, enamels, &c. are prevented from caking by an agent which will be deposited or coated on to the pigment particles, so that they will be unable to coalesce and form a tough, hard mass which would resist dispersion in the vehicle. Such coated particles, although they may form a sediment, are readily reincorporated in the vehicle by suitable agitation. Various types of such protective, agents may be used, and they may be applied in various ways. For lacquers having a base of nitrocellulose, cellular esters, ethers or other derivatives, the following may be used : rubber latex and sodium caseinate, which mav be used in a water medium : rubber, milled or raw, in a gasoline, benzene or other solvent medium; citric, tartaric, propionic acids or gelatine with glycerine, the medium being alcohol and toluol; stearine pitch in naphtha or gasoline: balata, silver stearate, tannic acid, hydrocarbon of gutta-percha, in gasoline : a substance known as Thermoprene SL and GP, comprising rubber heated with an organic sulphonyl chloride or sulphonic acid, in gasoline. In the case of oil and varnish vehicles, the following may be employed : rubber latex, pectin, sulphonated castor oil partially neutralized with ammonia, turkey-red oil, in an aqueous medium : rubber in a gasoline medium: pectin in gasoline or a paint vehicle; stearinepitch in a gasoline-naphtha mixture; sulphonated tallow, sulphonated cod oil, sulphonated petroleum fractions, sulphonated castor oil (if desired, partially neutralized) may be emulsified with or dissolved in gasoline or the paint vehicle: colloidal wax (consisting of carnauba and paraffin) may be dissolved in gasoline. For compositions used as undercoats for metals, such as modified glyptal (Registered Trade Mark), resin vehicles, rubber or stearine-pitch aispersed in gasoline may be used. The invention is applicable to various pigments, such as Titranox, lithophone, titanium oxide, iron oxide, barium sulphate, chrome green, whiting basic white lead carbonate, or mixtures thereof. The specific agent and method of depositing on the pigment particles vary according to the type of lacquer, paint, enamel or the vehicle to be manufactured, and the general character of its constituents. Examples are given of the application of the types of protective agents specified above to various pigments, and incorporation into various lacquers, paints &c.