GB517196A - Improvements in or relating to the production of urea-formaldehyde condensation products - Google Patents

Abstract

517,196. Urea-formaldehyde condensation products. ALBERT PRODUCTS, Ltd. July 22, 1938, No. 21823. Convention date, Aug. 12, 1937. [Class 2 (iii)] Urea and/or thiourea and aqueous formaldehyde are condensed in the presence of a solvent for the condensation product which is insoluble or difficultly-soluble in water so as to form an aqueous phase and a substantially non-aqueous phase containing the product. Suitable solvents are those containing a free OH group, e.g. benzyl', n-butyl and isobutyl alcohols. The yield of the product may be increased by the addition of water-soluble inorganic salts. The condensation, which may be carried out at 90-95‹C., may be commenced at a pH above 5, e.g., 6-9, and completed at ap H below 5, e.g., 3-4.5, the reaction mixture being finally neutralized and cooled ; the molecular proportions of formaldehyde to urea and/or thiourea are 1.5-2.5:1. The products are suitable for the production of lacquers, paints and moulding powders ; or impregnating and stiffening agents for fabric, and as adhesives and packing materials. In examples, urea and aqueous formaldehyde, rendered alkaline with caustic soda, are condensed in the presence of benzyl, n-butyl or isobutyl alcohol, the condensation being completed after acidification with phosphoric acid and the pH finally adjusted to 7 with caustic soda. In example (3) common salt is added to the reaction mixture, and in example (4) a mixture of urea and thiourea is employed.