GB598602A - Method of producing copolymer resins and products derived therefrom - Google Patents

Abstract

Permanently fusible resinous masses are made by forming an undehydrated reaction product by heating under reflux conditions and in the presence of an acid catalyst a monohydric phenol with an aldehyde, substantially all the latter being reacted with the former, the ratio of the aldehyde to the phenol being maintained to produce a permanently fusible resin, separately dissolving a polyhydroxy phenol in an aldehyde, while controlling the temperature so that it substantially inhibits any reaction between said constituents during the solution step, the ratio of the aldehyde to the polyhydroxy phenol being maintained to produce a permanently fusible resin, adding said solution to the undehydrated reaction product while the latter is maintained at an elevated temperature, thereby reacting the constituents of said solution in the presence of the acid catalyst and in the presence of said monohydric phenol-aldehyde reaction product until substantially all the aldehyde is combined with said polyhydroxy phenol, and dehydrating the resulting reaction mass. Heat-reactive compositions may be made by mixing the products with formaldehyde or a substance yielding formaldehyde on heating, such as hexamethylene tetramine. Monohydric phenols specified are phenol, cresol, cresylic acid, oxylenols; and polyhydroxy phenols are catechol, resorcin, hydroquinone, orcinol, phloroglucinol, pyrogallol. In an example, phenol is refluxed with 37 per cent formaldehyde solution and oxalic acid, to the hot reaction mixture is added a cooled solution of resorcinol in formalin, the whole is refluxed for a further period, and water and unreacted phenol removed by vacuum distillation. The proportion of mono-or poly-hydric phenol to aldehyde may vary from .5-.9 mols. of aldehyde. Other catalysts which may be used are citric, tartaric, acetic, hydrochloric, sulphuric, phosphoric, and boric acids, and other aldehydes are acetaldehyde, paraldehyde, propylaldehyde, the butyl aldehydes, the furfuraldehydes, or mixtures of aldehydes. The molar proportion of mono-or poly-hydric phenol to total phenol employed may range from 1-99 per cent; 8-12 per cent of hexamethylene tetramine, which may be in solution, may be added to the resin to give a heat-reactive composition, and alternatives to hexamethylene tetramine are the oxymethylenes, paraformaldehyde and reactive methylol compounds, e.g. that formed from phenol and excess formaldehyde in presence of an alkaline catalyst. An example is given of a low-temperature curing composition comprising the resin, water, glycerine, and formaldehyde solution, which is poured into moulds and hardened at 75-80 DEG C. Solvents for such compositions are denatured alcohol or acetone. The reactive compositions may be used for gluing sheets of wood, leather, and cardboard, and for bonding abrasive articles. Moulding compositions may contain the resin, a dye, a lubricant, and a filler which may be woodflour, calcium carbonate, kieselguhr, or a cellulosic filler. Specification 582,448 is referred to.