VERFAHREN ZUR HERSTELLUNG VON WASSERFREIEN RESORCIN-FORMALDEHYD-KONDENSATIONSPRODUKTEN MIT NIEDRIGEN MITTLEREN MOLEKULARGEWICHTEN

摘要

Production of non-aqueous resorcin-formaldehyde condensation products with low average molecular weights containing no undesirable proportions of free resorcin by the acid-catalytic condensation of resorcin with formaldehyde or a formaldehyde derivative at high temperatures in an inert organic solvent with the azeotropic, distillative separation of the reaction water, whereby the reaction takes place in an apolar solvent which is not miscible with water in which resorcin dissolves readily but the resorcin-formaldehyde condensation product dissolves only with difficulty and is specifically heavier than the solvent or reactant solution so that two fluid phases ar formed, the lower of which consists of molten condensation product. The solvent is preferably fed back in the circuit from the water separator into the reactant solution through the lower phase and the condensation product is extracted from the lower phase. It may be freed of undesired resorcin contents by subsequent further solvent extraction. Use for condensation products as adhesion promoters in technical rubber articles containing steel or textile cords or for the production of waterproof wood glue and textile impregnants.