GB773510A - Resol resins - Google Patents

Abstract

A resol resin is made by condensing a molar excess of phenolic material with formaldehyde in the presence of a salt of a divalent electropositive metal with an organic acid, said salt being at least partially soluble in the reaction mixture, at a pH of from 4 to 7 to produce a non-heat-hardenable novolak resin which is reacted with formaldehyde in the liquid phase, in the presence of alkali at a pH greater than 7, and stopping the condensation before the resol resin becomes insoluble. The molar ratio of condensed formaldehyde to phenolic material in the final produce exceeds 1 : 1. The phenolic material comprises phenol, meta-cresol, metaethyl phenol and mixtures thereof with or without other phenolic compounds. Specified metal salts comprise the benzoates, formates, acetates and lactates of barium, strontium, calcium, manganese, magnesium, zinc, cadmium, cobaltous cobalt and lead. Specified alkalies are the alkali metal hydroxides and carbonates, alkaline earth metal oxides and hydroxides, ammonia and organic bases. In the examples: (1) and (2) excess of phenol is refluxed with formalin in presence of zinc acetate, excess phenol being distilled off, the resultant novolak being condensed with formalin in the presence of sodium hydroxide; (3) excess of mixed cresols is refluxed with formalin and zinc acetate, excess cresol being distilled off and the resultant novolak condensed with formalin in the presence of ammonia. The products were suitable as plywood adhesives and in the preparation of paper laminated boards. Specification 757,392 is referred to.