ALKALIICURING TYPE MODIFIED UREA RESIN LIQUID

摘要

PURPOSE:To provide the titled resin liquid which is inexpensive and suitable for use in bonding wood and has excellent water resistance, consisting of an aq. rubber latex and a modified urea resin liquid resulting from the co-condensation of acetone with a precondensate obtd. by the condensation of urea with formaldehyde in a specified molar ratio. CONSTITUTION:1.5-12mol of formaldehyde is mixed with 1mol of urea. The mixt. is subjected to a condensation reaction with heating to obtain a precondensate of a urea resin. Acetone is added to the precondensate in a ratio of 0.3-3mol of acetone per mole of urea. The mixt. is subjected to a co-condensation reaction at 50-90 deg.C and an alkaline condition having a pH of 8.5-12 to obtain a modified urea resin liquid. Then 5-100pts.wt. aq. rubber latex (e.g. natrual rubber latex or a synthetic rubber latex such as styrene-butadiene rubber latex or chloroprene rubber latex) is mixed with 100pts.wt. said urea resin liquid to obtain the titled resin liquid.