GB421942A - Manufacture of condensation products from urea and formaldehyde - Google Patents

Abstract

Urea and formaldehyde are condensed in aqueous solution in the presence of zinc chloride with or without the addition of sucrose or phenol. The proportion of zinc chloride used is preferably between 2 and 57 parts to 100 parts of urea and the temperature of reaction preferably below 212 DEG F. Useful products are obtained by stopping the reaction at an intermediate stage. In an example, zinc chloride is dissolved in commercial aqueous formaldehyde and urea is added to the solution. The solution is then passed through coils maintained at a fixed temperature and discharged through cooling coils to yield a very stable syrupy liquid. The products may be converted into dry powder adhesives by drum or spray drying to yield a dry glue which, together with a little water is converted under heat and pressure to a strong bond. The product dried on paper forms an adhesive softened by moisture, and sheet material such as wood veneer, insulating board, asbestos board, cloth, tissue paper and wire cloth soaked in or coated with the product may be dried and then laminated in a hot press. It may be used as an adhesive for sticking leather or felt to rubber, as a lacquer or varnish, as a stiffener for textiles and composition sheets, as a waterproofing agent, as a base for films and film glues, as a binder for moulded products, as a base for cements and as a base for metal-cleaning and other polishes.ALSO:Condensation products of urea and formaldehyde in aqueous solution prepared in the presence of zinc chloride with or without the addition of phenol or sucrose may be used as adhesives. The liquid product may be spray or drum dried to yield a powder glue or it may be dried on paper, wood veneer, insulating board, asbestos board, cloth, tissue paper and wire cloth and the products laminated in a hot press. It may also be used as an adhesive for sticking leather or felt to rubber.