| 摘要 |
Provided are a method for preparing an amino-based thermosetting resin to reduce the amount of free formaldehyde in a resin, and an adhesive for plywood or board containing the resin as an efficient component. The method comprises the steps of injecting urea and formaldehyde in a molar ratio of aldehyde group/amino group of 1.6-2.3, adjusting the pH to be 7.5-10.0, increasing the temperature slowly to 75-85 deg.C, maintaining the temperature for 20-60 min for performing addition reaction, adjusting the pH to be 4.5-5.5, and condensation polymerizing the reaction mixture at 80-95 deg.C; adjusting the pH to be 8-10, and injecting an amino-based compound at 70-90 deg.C to polymerize the reaction mixture, thereby obtaining a final molar ratio of aldehyde ratio/amino group of 0.5-2.0; and adding ammonia, formaldehyde or an amine-based additive to the obtained one. Preferably the amine-based compound is acrylamide, melamine, n-methylol acrylamide or urea.
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