SLIGHTLY CONTAMINATING RESOL AND PROCESS FOR PREPARING THE SAME

摘要

The invention relates to a slightly contaminating resol and to a process for producing the same used for cements, laminates, impregnations and grinding materials. According to the invention, the resol has a content of free phenol of less than 5 % by weight in the form of condensates of phenol which are trifunctional with respect to formaldehyde and alkylidenepolyphenols in a molar ratio of the phenolic hydroxyl groups in the trifunctional phenols with respect to the hydroxyl groups in the alkylidenepolyphenols of 9:1 to 3:7 with formaldehyde in a molar ratio of the total number of phenolic hydroxyl groups with respect to formaldehyde of 1:1.2 to 1:2. According to the invention, the process consists in reacting the total amount of trifunctional phenols with formaldehyde in the presence of a basic catalyst at a temperature ranging between 20 ...100 degree C in a first step and continuing the reaction till a formaldehyde consumption of 50 to 90 % of the used formaldehyde and then adding alkylidene polyphenols and continuing the condensation in a mixture.