BOTH PREPARATION AND STABILITY FOR HIGH SOLID CONTENT ETHERIFIED MELAMINE-FORMALDEHYDE RESIN

In this paper,paraformaldehyde was used as substitute for all or partial formaldehyde to prepare high solid content melamine-formaldehyde resin,which was modified by methanol whereafter and the etherification reaction was confroled by reactive condifious such as time and pH of media. The effects of the content of paraformaldehyde and methanol,the mole ratio of melamine to formaldehyde,and the other reaction conditions on the stability,the solid content and the content of the free formaldehyde are further discussed.The optimum formula rafio was n(melamine):n(formaldehyde):n(methanol)=1:3.5:5 and the optimum reaction conditions were that media pH was 6.5～7.0;reaction time,45 min and the content of free-formaldehyde reduced below 1.0% when the mixes of urea 2.0% and borax were added info reaction system.in the meantime.