高固含量蜜胺树脂的合成研究

Study on synthesis of high solid content melamine resin

以多聚甲醛代替甲醛溶液,合成了高固含量蜜胺树脂。研究了不同反应物物质的量比、体系pH、反应温度、反应时间对产物中游离甲醛含量、羟甲基含量及粘度的影响,通过红外光谱分析验证了蜜胺树脂的交联反应机理。结果表明,高固含量蜜胺树脂合成的适宜工艺条件为:n(三聚氰酸):n(多聚甲醛)=1∶2.8,pH8.5～9.5,反应温度85～90℃,时间1.0～1.5h,产品固含量70%,粘度687mPa.s,游离甲醛质量分数0.36%。

The high solid content of melamin resins were synthesized by using paraformaldehyde instead of formaldehyde solution.The effects of different molar ratio of reactants,pH of system,reaction temperature and reaction time on the content of free formaldehyde and methylol and the resin viscosity were investigated.The cross-linking reaction mechanism of melamine resin were verified by IR.The results showed that the optimal synthetic conditions of high solid content melamin resin were as follows：n（cyanuric acid）∶ n（paraformaldehyde）= 1∶ 2.8,pH 8.5 ～ 9.5,reaction temperature 85 ～ 90 ℃,reaction time 1.0 ～ 1.5 h.The solid content,viscosity and free formaldehyde of the procucts were 70%,687mPa.s and 0.36%,respectively.