GB636496A - Method of producing a composite synthetic resin and product thereof - Google Patents

Abstract

A composite two-stage resin is produced by condensing a resin-forming primary aryl amine or a secondary di-aryl amine with an aldehyde and forming a thermoplastic aromatic amine-aldehyde resin constituting 5 to 8 per cent of the composite resin, mixing therewith a solution of unreacted aldehyde and unreacted polyhydroxy benzene, a derivative, or a substitution product thereof, the molar ratio of aldehyde to polyhydroxy benzene, homologue, or derivative being less than 1 : 1, and reacting the solution by heating in the presence of the pre-condensed aromatic amine-aldehyde resin. The products are suitable as moulding materials, adhesives for laminates of wood, cloth, leather, natural or synthetic rubber, asbestos or glass fibres. Other fillers include wood flour, dye, calcium carbonate, kieselguhr or cellulose. Specified are aldehydes: formaldehyde, acetaldehyde, paraldehyde, propionaldehyde, butyraldehyde, furfuraldehyde, glyoxal; polyhydroxy benzenes: resorcinol, alkyl resorcinols, ethers including monomethyl resorcyl ether, esters including resorcinol disulphonic acid esters, pyrogallol, phloroglucinol and their homologues. Hardening agents include hexamethylene tetramine or methylol compounds such as dimethylol para cresol, polymethylol phenols or their salts, methylol resorcinol, methylol xylenols, dimethylol urea, dimethylol thiourea and methylol melamine. A suitable polymethylol phenol is prepared by reacting phenol and formaldehyde with an NaOH catalyst at 20 DEG to 25 DEG C. In examples: (1) ortho amino diphenyl and formaldehyde are reacted until combination is complete and a solution of resorcinol in formalin is then added and the mixture refluxed; (2) the general procedure of (1) is followed using aniline in place of the ortho amino diphenyl; (3) a solution of diphenylamine replaces the aniline of (2). The low curing temperature of the products makes them suitable for forming large laminated articles, e.g. furniture, sections of aeroplanes and hulls of dinghys. The Specification as open to inspection under Sect. 91 comprises also the preparation of one stage resins by employing a ratio of aldehyde to dihydroxy benzene of more than 1 : 1, preferably 1 : 1 to 2 : 1. The use of tertiary amines and the reaction of an aromatic amine with an aldehyde in the presence of a partially or completely condensed polyhydroxy benzene-aldehyde reaction mixture are also referred to. This subject-matter does not appear in the Specification as accepted.