GB302737A - Manufacture of artificial resins - Google Patents

Abstract

302,737. Soc. of Chemical Industry in Baste. Dec. 21, 1927, [Convention date]. Urea-formaldehyde condensation products.- Water-insoluble resins are produced by adding to a urea-formaldehyde reaction mixture before or at any stage in the condensation, in an alkaline medium, a substance capable of forming with formaldehyde or its condensation products with urea or its derivatives in presence of OH ions a water-insoluble resin, and then further heating until on cooling or mixing with water, a waterinsoluble resin separates. The additional substances mentioned are aromatic amines such as aniline and naphthylamine and their derivatives such as anhydroformaldehydeaniline, substituted ureas or urea derivatives such as thiourea and phenyl urea, cyanamide and its derivatives such as dicyandiamide, urea, acid amides of high molecular weight such as biuret, mono- and polyhydric phenols such as phenol, resorcinol, naphthol, pyrogallol and its derivatives such as tannin, phenol-formaldehyde condensation products, and sulphurized phenol resins. For use in Jacquers, the products may be separated at a stage where they are soluble in alcohol. If the agents added are not sufficiently soluble, organic solvents such as alcohol or acetone may be added. The resins may be hardened in alkaline mediums and are therefore suitable for use with basic pigments such as zinc white, white lead, ferric oxide &c. and for application upon basic materials. In the examples, (1) urea, phenyl-urea, and formaldehvde are mixed with caustic soda solution and boiled for 4 hours, the resin being precipitated by water; (2) urea, thiourea, and formaldehyde are heated with caustic soda solution; (3) urea is dissolved in 40 per cent formaldehyde and the solution clarified by active carbon; it is then heated to 100‹ C. until a sample yields a milky precipitate on treatment with water, and it is then boiled with (i) phenyl urea, thiourea, or aniline and caustic soda, (ii) dicyandiamide and ammonia, (iii) urea, biuret, anhydroformaldehydeaniline or #-naphthylamine and caustic soda, (iv) phenol and hexamethylene tetramine, (v) soluble phenol-formaldehyde condensation product, alcohol, and caustic soda, (vi) liquid sulphurized phenol resin, alcohol, and ethylene-diamine, (vii) #-naphthol, alcohol and hexamethylene-tetramine.