Melamine resins, a process for their preparation and their use and molding compositions produced from the resins

摘要

PCT No. PCT/EP82/00013 Sec. 371 Date Sep. 30, 1982 Sec. 102(e) Date Sep. 30, 1982 PCT Filed Jan. 25, 1982 PCT Pub. No. WO82/02717 PCT Pub. Date Aug. 19, 1982.Modified melamine-formaldehyde resins having a melamine:formaldehyde molar ratio of 1:(1.27 to 0.7) are prepared by heating melamine in an aqueous solution or suspension with formaldehyde in a melamine:formaldehyde molar ratio of 1:(1.27 to 0.7) at a pH value of 8 to 11 and at temperatures of 105 DEG to 160 DEG C. until the finished resin has reached a dilutability with water of 1:(0.1 to 4) at 20 DEG C., and, before, during or after the condensation reaction, adding less than 25% by weight of a glycol ether of the formula R(OCH2CH2)nOH in which R denotes alkyl having 1 to 4 C atoms and n denotes an integer from 1 to 5, and/or of p-toluenesulfonamide. The resins are used in particular for the production of molding compositions.