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将水溶性的三聚氰胺树脂改性成油溶性的三聚氰胺树脂,目的是与性能优越的醇酸树脂混溶,提高其耐水性、耐候性、耐磨性和耐腐蚀性。用醇类改性主要有甲醇、乙醇、丁醇和异丁醇,其中甲醇、乙醇极性较大,而异丁醇由于甲基位阻效应,反应较慢,所以丁醇改性效果较好。用丁醇改性有一步法和两步法,但没有本质的区别。一步法是羟甲基化和醚化一步完成,两步法是羟甲基化和醚化分步完成,一步法反应始终处于弱酸性,而两步法是先碱性的羟甲基化后弱酸性的醚化阶段,国内目前主要是两步法。本文主要是对三聚氰胺树脂丁醇改性过程中产生的凝胶现象进行分析与探讨,通过实验并提出了防止凝胶现象发生的相应措施。
The water-soluble melamine resin is modified into an oil-soluble melamine resin with the objective of being miscible with a superior alkyd resin to improve its water resistance, weatherability, abrasion resistance and corrosion resistance. Alcohol modified mainly methanol, ethanol, butanol and isobutanol, of which methanol, ethanol greater polarity, and isobutanol due to methyl steric effect, the reaction is slow, so the better butanol modification. Butanol modified one-step and two-step method, but there is no essential difference. One-step methylation and etherification is a one-step process, two-step methylation and etherification is completed step by step, one-step reaction is always weakly acidic, and two-step method is the first alkaline methylated Weak acid etherification stage, the current domestic mainly two-step method. This paper mainly analyzes and discusses the gel phenomenon generated during the melamine resin butanol modification, and puts forward some corresponding measures to prevent the gel phenomenon.