Preparation of urea-formaldehyde resin adhesive

A preparation method of urea-formaldehyde resin adhesive with low free formaldehyde content and high adhesive strength was presented. Effects of purity of raw materials, molar ratio of urea and formaldehyde, reaction temperatures and reaction time on the properties of urea-formaldehyde resin adhesive were studied. After addition of formaldehyde, urea was added in three portions respectively at proper pH value and temperature to react, then adhesive with stable adhesive performance and good product quality for construction was obtained.