Modified urea-melamine resin solns. prodn. - by adjusting ph of formaldehyde soln. contg. methanol using tri:ethanolamine, sodium hydroxide and ammonium hydroxide

摘要

Prepn. of modified urea-melamine resin solns. (I) employing NaOH and/or triethanolamine and/or NH4OH as catalyst by multi-stage condensation is claimed. The pH of a formaldehyde soln. contg. 5-11.5 wt.% methanol is adjusted to 7.5-8.1 by the addition of triethanolamine or NaOH or NH4OH, to pH 8.7-10 esp. 8.7-9.3 by 0.5-10 esp. 0.5-5 wt.% substances contg. reactive -CONH2- and/or -CH2OH- and/or -CH(OH)-gps. and further addition of NaOH, and melamine and urea are added in a molar ratio of 1:1.3-2 at a temp. under 323 esp. 308-318 K to produce a molar ratio of amino cpds. to formaldehyde of 1:1.5-1.9, and condensn. is carried out at 363-373 K upto a water-compatibility of 1:1-2 and the pH-value falls from 8.7-9.3 to 8.0-8.2 during the first 15-25 min. of condensation by the step wise or continuous addn. of NaOH and condensn. is terminated at pH 7.5-8.0. USE/ADVANTAGE - (I) are used in the impregnation of webs of paper used in the mfr. of laminated plastics. The prod. is inexpensive.