Preparation of a Urea-Formaldehyde Adhesive

To a resin kettle are added 286 gm of a 70% solids urea-formaldehyde resin (see note below) of the type described in Section 2-1, 80 gm (0.80 mole) furfuryl alcohol, 44 gm wood flour, 1.1 gm triethanolamine, and 2gm tricalcium phosphate. The mixture is stirred (pH approximately 8) and slowly heated to about 90 C over a y-hr period. The temperature is kept at 90°C for about 15 min and then cooled to 30°C over an 80-min period. The product is now ready to be cured with either one of the following catalysts. (Before addition of the catalyst, the adhesive resin is stable for over 3 months at 80°F.) 

6-hr working life catalyst 3 gm ammonium chloride and 10 gm water 

2-hr working life catalyst 2gm ammonium chloride, 1 gm ferric 

NOTE The urea-formaldehyde resin is one prepared from a formaldehyde urea molar ratio of 1 1 to 2 1 and is about 70% solids. However, a solid resin may be used to give similar results. 

The adhesive gives the following result according to tests as provided by the Army-Navy Aeronautical Specification Glue Cold Setting Resins, An-G-8, dated April 25, 1942  

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