ENVIRONMENTALLY-FRIENDLY UREA-FORMALDEHYDE RESIN ADHESIVE AND PREPARATION METHOD AND USE THEREOF

摘要

#$%^&*AU2020101072A420200723.pdf#####ABSTRACT The present invention belongs to the field of adhesives, and discloses an environmentally-friendly urea-formaldehyde resin adhesive and a preparation method and use thereof. The preparation method of the environmentally-friendly ureaformaldehyde resin adhesive includes: heating a formaldehyde solution to 30-40C, and adding urea for reaction for 2-10 min; heating to 45-650 C, adjusting the pH value of the system to 6.5-8 using an alkaline solution, and adding urea for reaction for 2040 min; stopping heating after heating to 85-950 C, and adding ammonium chloride in four batches at this temperature for curing reaction; adjusting the pH value to 6.5-8 using an alkaline solution and ammonia water, adding urea, and reducing the temperature to 78-850C for conducting reaction for 30-50 min; starting to conduct heating when the temperature drops to 72-76C, adding melamine when the temperature rises to 82-880C, and keeping the temperature for reaction for 20-40 min; adding thiourea when the temperature drops to 73-780C, and keeping the temperature for reaction for 5-15 min; adjusting the pH value to 9±0.3 using an alkaline solution when the temperature drops to 68-72°C; and adding urea for reaction for 20-40 min when the temperature drops to 63-670C, and cooling the system to room temperature. The resulting environmentally-friendly urea-formaldehyde resin adhesive has low content of free formaldehyde and high strength.