GB676381A - Improvements in or relating to thermoset resinous bodies - Google Patents

Abstract

A cellular expanded thermoset resinous body is made by heating between 110 DEG C. and 350 DEG C. a liquid composition containing (a) 70 to 97 per cent by weight of a thermosetting aqueous liquid partial reaction product of one mol. of at least one monohydric phenol selected from phenol, cresols and xylenols and between 1 and 3 mols. of at least one aldehyde selected from formaldehyde, polymers thereof, acetaldehyde, hexamethylenetetramine and furfural, the reaction having been effected in the presence of 0.05 to 5 per cent, by weight of the phenol, of an alkaline catalyst for the reaction and at least 3 per cent by weight of water, based on the weight of the phenol and aldehyde, and the reaction product having from 3 to 25 per cent by weight of water, a pH of 3 to 10 and a viscosity of 1 to 250 poises at 25 DEG C.; (b) 5 to 0.1 per cent by weight of a surface-active organic agent having foam producing properties; and (c) 25 to 1 per cent by weight of a peroxide selected from calcium, lead, sodium, potassium, barium, magnesium, zinc and urea peroxides. The condensation may be effected at 50 DEG to 125 DEG C. and the desired pH value may be obtained by adding lactic, tartaric, citric, acetic, oxalic, malonic, formic, hydrochloric, sulphuric or phosphoric acid to the condensation product. Excess water may be removed by vacuum dehydration. Catalysts specified are sodium, potassium, barium and calcium hydroxides, calcium oxide, sodium carbonate and bicarbonate, barium carbonate, ethylene diamine, propylene diamine, ammonia, hexamethylenetetramine and aniline. Foam-producing agents specified are the dialkyl alkali sulphosuccinates in which the alkyl groups each have between 4 and 8 carbon atoms, e.g. dibutyl, dihexyl and dioctyl sodium sulphosuccinates; monoalkylbenzene alkali sulphonates in which the alkyl group is a long chain having from 10 to 18 carbon atoms; alkyl aryl polyether alcohols and sulphonates in which the alkyl group is a long chain having from 8 to 18 carbon atoms; alkali soaps of fatty acids having a chain of 12 to 19 carbon atoms, e.g. sodium palmitate, stearate and oleate; polyethylene ethers of sorbitan monoesters of fatty acids containing 12 to 18 carbon atoms; and alkyl and aralkyl quaternary ammonium compounds, e.g. alkyl benzyl ammonium chloride and diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride in which at least one alkyl group has 10 to 18 carbon atoms. The phenol aldehyde resin may be plasticized with a polyhydric alcohol, e.g. glycerol and aliphatic glycols containing up to 8 carbon atoms, in amount up to 1/2 mole. of the alcohol per mole. of phenol. Up to 8 per cent by weight of the composition of at least one thermoplastic resin selected from polyvinals, polyvinyl esters, and hydrolysis products thereof, cellulose esters and ethers, polyvinylidene chloride, polyacrylates, and polymers of acrylic acid esters and of alkyl acrylic acid esters, may be incorporated in the compositions. Up to 10 per cent by weight of the composition of finely-divided solids, e.g. silica flour, wood flour, walnut shell flour, asbestos fibres, silica gel, acetylene black, aluminium powder, mica and cotton fibres, may also be added to the compositions prior to heat treatment. Examples are given. The compositions find use in thermal insulation, e.g. refrigerator casings, sound insulation, decorative bodies as in window p displays, and structural members of great strength for a given weight, e.g. air foils, floats and non-sinkable boats.