GB584933A - Hardenable compositions containing aminotriazine-aldehyde resins - Google Patents

Abstract

A condensation product formed from a mixture comprising an aldehyde and an aminotriazine is mixed with ammonium silicofluoride or ammonium borofluoride as curing catalyst. Examples describe (1) the making of an adhesive, e.g. for plywood, from water, a water-soluble melamine - formaldehyde resin, and ammonium silicofluoride; (2) a composition from trimethylol melamine, walnut shell flour, tricalcium phosphate, and ammonium silicofluoride. Ammonium borofluoride may be substituted in each example, and buffering substances may be added, e.g. sodium formate, acetate, or sulphite, and disodium phosphate. For the preparation of the resins, aminotriazines specified are: melamine, monophenylmelamine, diphenyl melamine, triphenyl melamine, ammeline, thioammeline, ammelide, formoguanamine, acetoguanamine, lauroguanamine, stearoguanamine, aminotriazines listed in U.S.A. Specification 2,197,357, mixtures of the foregoing, and mixtures obtained by thermodecomposition of dicyandiamide alone or in presence of solvents, diluents and other reactive materials such as aniline. Aldehydes are formaldehyde or polymers thereof, benzaldehyde, furfural or mixtures thereof. Modifying bodies may also be concerned in the preparation of the resin, e.g. ureas, thiourea, dicyandiamide, aniline, phenol, resorcinol, the cresols and xylenols, but the aminotriazine must amount to at least 5 per cent by weight of the modifying body. Suitable resins may be prepared according to U.S.A. Specifications 2,197,357 and 2,260,239 and Specification 574,016. Adhesive compositions should preferably contain at least 70 per cent resin, 0-20 per cent walnut shell flour or wood flour, 0.1-5 per cent ammonium silico- or boro-fluoride, preferably .6 per cent ammonium silicofluoride, and 1-4 per cent of an anti-caking agent such as tri-calcium phosphate. Gums, starches, dispersing or wetting agents may also be present. The adhesives may be used in the manufacture of plywood and paper-board, for joining cellulosic sheets and wooden surfaces generally, and are vermin-proof by reason of the insecticidal properties of the ammonium salts. The catalysts may also be used in aminotriazine-aldehyde moulding compositions.