Patent GB-544715-A (GB)
Title: Manufacture of coating, impregnating and like compositions
IPC: C08J3/11
Filed: 1940-10-23
Abstract: 544,715. Resinous coating &c. compositions ; artificial filaments ; films. DU PONT DE NEMOURS & CO., E. I. Oct. 23, 1940, No. 15584. Convention date, Oct. 24, 1939. [Classes 2 (ii) and 2 (iii)] Stable dispersions, suitable for coating, impregnating &c, are obtained by mixing, with vigorous stirring, a solution of a synthetic linear polyamide with a liquid which is a non- solvent for the polyamide but is at least partially miscible with the solvent employed, separating the precipitated polyamide, and then redispersing it in the same or a different non- solvent by vigorous mechanical dispersing means, e.g. a colloid mill. A dispersing agent may be added; other additions include plasticizers, waxes, resins, pigments and dyes. Polyamides include interpolymers, e.g. those derived from diamines, dibasic acids and glycols. Specified solvents are formic, hydrochloric, sulphuric, pyruvic and acetic acids; phenol, cresols, xylenols, p-butylphenol, thymol, diphenylolpropane and o-hydroxydiphenyl ; benzyl alcohol, butyl alcohol, ethoxyethanol ; formamide and dimethylformamide; ethylene chlorhydrin ; methallyl alcohol, and methylethinylcarbinol. Specified dispersion media are water, methanol, ethanol, acetone, methyl ethyl ketone, ethyl acetate, ethyl butyrate, amyl acetate, ethyl ether, isopropyl ether, dioxane, benzene, toluene, petroleum hydrocarbons, dichloroethane, chloroform, carbon tetrachloride, dichloroethylene, trichloroethylene, tetrachloroethylene, trichloroethane, tetrachloroethane, pentachloroethane and mixtures. Specified resins are polymethacrylates, phenolformaldehyde, urea-formaldehyde, vinyl resins, neoprene, alkyd resins, ethylene-sulphur dioxide resins, rosin, cellulose esters and ethers and hydrocarbon polymers, e.g. rubber, guttapercha, polyetbylene and polybutylene. Specified dispersing agents are lecithin, saponine, alkaline solutions of proteins, e.g. casein and soya beans, polyvinyl alcohol and partially hydrolyted polyvinyl acetate. Suitable plasticizers, pigments and dyes are also indicated. Examples are given of the production of aqueous and acetone. dispersions. The dispersions may be employed for coating cloth, paper, leather, rubber, wood, wallboard, regenerated cellulose and ceramic ware ; for the production of laminated products, and for coating metal wires, sheets and articles. Specifications 461,236, 461,237, 474,999 and 540,135 and U.S.A. Specifications 2,071,250 and 2,130,948 are referred to. Specification 483,765, [Group III], also is referred to. The Specification as open to inspection under Sect. 91 describes also the removal of the original liquid by distillation and the use as solvent of a mixture of liquids containing a higher boiling non-solvent, followed by distillation to leave the polyamide dispersed in the non-solvent. In an example, polyhexamethylene adipate is dissolved in formic acid and poured into agitated metbanol and, following dilution, with acetone, the formic acid is removed, as methyl formate, by distillation. Further, it is stated that the dispersions may be added to solutions of cellulose derivatives to be used for casting films or spinning fibres to improve their dyeing properties and as a delustrant. This subject-matter does not appear in the Specification as accepted.