Study on the curing characteristics of low toxicity UF resin in differrent curing system

Gelation time,pot life and pH value of six kids of low toxic urea-formaldehyde(UF) resins in different curing systems were studied. In one-component curing system the gelling is the most quick for ammonium per-sulfate. In the binary curing system of phosphate and ammonium chloride,the gelling is very quick,but the pot life is short. Added urea of 2% - 3% in two-component or multi-component curing system, gelation time isn't affected greatly. Urotropine is excellent in prolonging pot life. Study on changing of pH value of UF resin after adding hardener showed that pH value droped quickly during 15 minutes and it went to stabilizing after 30 minutes