GB717093A - Improvements in laminating wood and method of making same - Google Patents

Abstract

A composition comprising a phenol-formaldehyde resin capable of being converted to insoluble-infusible form under the action of heat and a methylene-yielding hardening agent, a methylene-yielding hardening agent for the resin, e.g. hexamethylene tetramine or para-formaldehyde, a rubbery butadiene-acrylonitrile copolymer preferably containing 15-45 per cent. by weight of combined acrylonitrile and which is compatible with the resin and has never been dissolved in a solvent, and a filler, e.g. wood flour, silica such as sand or diatomaceous earth, carbon black, clay, asbestos fibres, or cellulose fibres, is mixed and sheeted and then used for bonding layers of wood (see Group VIII). The resin may be a straight phenol-formaldehyde resin based on tri-functional phenols, e.g. ordinary phenol or modified by using tri-functional phenol with another phenol which can be tri-functional, di-functional or mono-functional, e.g. a resin based upon ordinary phenol but modified or co-condensed with a lesser proportion of any of the following phenols, which may be either pure or mixed: the cresols, the xylenols, the tri-methylphenols, mono-chlorophenols, dichlorophenols, diamylphenols, diisopropylphenols, p-tertiary-butylphenol, p-phenyl-phenol, resorcinol, and hydroquinone. It is preferred to employ a resin based upon ordinary phenol and the phenol cardanol obtained from cashew nut shell oil by heating, in an amount of 3-12 mol percentage of the latter based on the 2 phenols. Preferably the resin and the rubbery butadiene-acrylonitrile copolymer are used in proportions ranging from 30 to 70 per cent. by weight of the resin and correspondingly from 70 to 30 per cent. by weight of the copolymer based on the resin and the copolymer.