GB520828A - Improvements in and relating to the production of aqueous compositions comprising thermo-setting resins and to the applications thereof - Google Patents

Abstract

520,828. Phenol-aldehyde resins. NEVIN, J. V. Aug. 3, 1938, No. 22986. Convention date, Aug. 11, 1937. [Class 2 (iii)] Cresols, xylenols, or both, are reacted with an aldehyde, e.g., formaldehyde, in the presence of triethanolamine and of at least 10 per cent. of sodium hydroxide (or an equivalent amount of other alkali) calculated on the weight of cresol and xylenol to obtain a partial condensate, when the reaction is arrested by addition of water or alcohol containing at least 6 per cent. of sodium hydroxide (or the equivalent thereof) and cooling the mixture. There may also be present other hydroxy-aromatic compounds, e.g., phenol, resorcinol, hydroquinone, or #-naphthol; gums, e.g., gum accroides; and dispersing agents. In examples: hydroquinone, phenol, xylenol, and cresylic acid, or #-naphthol and cresylic acid, are reacted with formaldehyde solution in the presence of triethanolamine and of 13.3 per cent. of sodium hydroxide, the reaction being arrested by addition of a dilute aqueous solution of 8 per cent. of sodium hydroxide. The solutions may be used for coating or impregnating, or as binders for fibre board or plywood. U.S.A. Specifications 2,068,759 and 2,068,926 are referred to. According to the Specification as open to inspection under Sect. 91, oleic acid may also be present during the reaction. In examples: xylenol, or cresylic acid with or without resorcinol, phenol, or gum accroides, and formaldehyde are reacted in the presence of oleic acid, triethanolamine, and 10 per cent. of sodium hydroxide the reaction being arrested by a dilute aqueous solution of 6 per cent. of sodium hydroxide. This subject-matter does not appear in the Specification as accepted.