Phenol-formaldehyde impregnating resin prodn.

摘要

The process consists of (a) providing a formaldehyde source such as a phenol-formaldehyde pre-condensate; (b) incorporating phenol in the formaldehyde source in the cold; (c) bringing the syrup to the formaldehyde source of phase (b); (d) maintaining the pH of the reaction mixt. at 7-10 by means of an inorganic base such as caustic soda; (e) heating the reaction mass and maintaining it at 70-90.5 deg.C; (f) stopping the reaction by cooling when it reaches the predetermined condensation grade; (g) concentrating to the desired solids content; (h) adding alcohol; and (i) recovering the resin after cooling.