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第43卷第2期 2013年2月
涂料工业
PAINTCOATINGS INDUSTRY
水性封闭异氰酸酯乳液的合成及稳定性研究
Vol.43No.2 Feb.2013
李阿峰"，樊国栋"·，李会宁，陈华"，赵琪’（1.陕西科技大学教育部轻化工助剂化学与技术重点实验室，西安710021：2.肇庆千江高新材料科技有限公司，广东肇庆526238）
摘要：采用甲苯二异氰酸酯（TDI）、三羟甲基丙烷（TMP）、二羟甲基丙酸（DMPA）为原料，2-甲基咪唑为封闭剂，三乙胺为中和剂制备了水分散封闭异氯酸酯（WBI)乳液，考察了中和剂和Zeta电位(-电位)对WBI乳液稳定性的影响，探讨了乳液耐电解质能力及其温敏特性对其解封温度及双组分聚氨酯漆膜性能的影响。实验结果表明：用三 0 电位绝对值增大，乳液粒径减小、耐电解质能力增强，乳液的稳定性提高。乳液的Zeta电位及粒径受温度影响较小，说明乳液较为稳定。DMPA用量为20%~25%（摩尔分数）较适宜。差示扫描量热法（DSC）分析表征其解封温度为 125.6~138.1℃，应用表明此类WBI作为固化剂可以赋予涂料较好的耐水性、耐醇性、硬度及耐冲击性。
关键词：水分散封闭多异氰酸酯；Zeta电位；稳定性；二羟甲基丙酸；粒径
中图分类号：TQ630.7
文献标识码：A
文章编号：02534312(2013)02001805
StudyonSynthesisandStabilityofthe
WaterborneBlockedIsocyanateEmulsion Li Afeng', Fan Guodong'*, Li Huining’, Chen Hua', Zhao Qi
(1. Key Laboratory of Additives Chemistry & Technology for Light Chemical Industry of Ministry of
Education, Shaanxi Unitersity of Science & Technology, Xian 710021, China;
2. Zhaoqing Rivers High Tech materials Co. ,LTD. ,Zhaoging,Guangdong 526238, China)
Abstract : Waterbome blocked isocyanate emulsion ( WBI) was synthesized with toluene 2, 4 disocya-nate (TDI), trimethylolpropane (TMP), dimethylol propionic acid (DMPA) as the reactants and 2 meth-ylimidazole (2 - Ml) as blocked agents and triethylamine as nentralizer. The influence of neutralizer and Ze: ta potential on stability of WBI emulsion was studied, The hydrolyte resistance and temperature dependence of emulsion and unblocking temperature of WBI and properties of two - component polyurethane film were discussed. The results showed that when triethylamine ( TEA) was used as neutralizer, the emulsion provid-ed good stability and storage stability due to the small particle size. When the neutralization was up to 100% , the stability of emulsion was the best. With the increase of DMPA, the stability of the emulsion was improved. The Zeta potential and particle sized were less influenced by temperature. Suitable mole fraction of DMPA is 20% ~ 25%. The unblocking temperature was 125. 6 C to 137. 8 ℃ by DSC test. The WBI could be used as curing agent to provide better water resistance, alcohol resistance, hardness and impact proverties of coatings.
Key Words : waterborne blocked isocyanate; Zeta potential; stability; dimethylol propionic acid; parti-cle size
水性树脂的制备多采用外加乳化剂或自乳化的方式提供亲水基团，以解决树脂在水相中的分散问题，所制备的水性封闭型多异氰酸酯交联固化剂可与水性产品形成单组分树脂(1-2)。水分散封闭异氰酸酯（WBI)的合成多是在分子链上
引人亲水扩链剂[3-5]，如二羟甲基丙酸（DMPA)[6},使其能自乳化,亲水基团的含量对水性聚氨酯的性能有直接的影响7-9。但在引入亲水基团来提高分散体综合性能的同时，也会带来分散体稳定性的间题。在生产水性封闭异氰酸酯分
【基金项日】陕西省科技攻关项目（2008K07-32）：陕西省教育厅重点实验宝重点科研计划项目（09JS061）；陕西科技大学研究生创新基金资助。
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