脲甲醛预聚合对酞菁绿G颜料微胶囊化的影响

The Effect of Pre-polymerization of Urea-formaldehyde on Microencapsulation of Phthalocyanine Green G

从脲、甲醛的预聚反应条件入手,讨论了脲甲醛量比、反应介质的pH值、催化剂和反应温度对酞菁绿G颜料微胶囊化过程以及微胶囊结构、表面形态、粒径及其分布和包埋率的影响。实验结果表明,当脲甲醛量比为n(脲):n(甲醛)=1:2.0,以氢氧化钠为碱性催化剂,反应介质pH值=8.0,反应温度70℃,反应时间1小时,得到的脲-甲醛预聚物水溶性好,用原位聚合法制备微胶囊时可以避免发生微胶囊表面形态呈非球形、凹陷和开裂。在以上条件下,制得了包覆结构紧密、包埋率较高、粒径分布均匀且平均粒径为3.2μm的球形固体微胶囊。

The effects of urea-formaldehyde pre-polymerization conditions, including the molar ratios of urea and formaldehyde, pH value of the reaction medium, catalyst, and reaction temperature, on the formation of Phthalocyanine Green G microcapsules were discussed, along with the structure and particle surface shape, the size and distribution of particle size as well as the microencapsulated ratio of the core material of the microcapsules. The results showed that when the molar ratio of urea-formaldehyde was n(urea):n(formaldehyde)=1 :2.0, NaOH was used as the catalyst, pH=8.0, reaction temperature=70℃, and reaction time=1 h, the resulting urea-formaldehyde resin exhibited good water solubility. The problem of non-spherical shape and sunken and splitting surface were avoided when such microcapsules were prepared by an in-situ polymerization. Under the above conditions, well-microencapsulated solid spherical microcapsules with a high ratio of microencapsulated core material, an average diameter of 3.2 μm, and a uniform distribution of particle size were achieved.