重防腐涂料用水性环氧乳液的制备

Preparation of waterborne epoxy emulsion for heavy-duty anticorrosion coating

采用固体双酚A型环氧树脂与高分子量聚醚反应合成水性环氧树脂专用非离子型乳化剂,然后结合相反转技术制备水性环氧乳液。讨论了催化剂三氟化硼乙醚(BF3-乙醚)的用量对环氧树脂CYD011和聚乙二醇PEG6000反应体系环氧值的影响,并利用红外光谱和凝胶渗透色谱对合成乳化剂的结构进行表征,探讨了环氧树脂与PEG6000的摩尔比、乳化剂质量分数、乳化温度及不同分子量的环氧树脂对乳液性能的影响。结果表明,当环氧树脂的环氧当量为450～500,乳化温度为75℃、催化剂用量为0.40%、n(环氧树脂)∶n(PEG6000)=1∶1、乳化剂质量分数为15%时,所制得的水性环氧乳液粒径小于1μm,稳定性高。由此乳液制备的涂料涂膜柔韧性为1mm,冲击强度为50kg·cm,浸泡在质量分数为5%的NaCl溶液中17d完好,耐盐雾480h完好。该乳液可应用于重防腐涂料。

A specified nonionic emulsifier for waterborne epoxy resin was prepared by reaction between highmolecular weight polyether and solid bisphenol A epoxy resin, and then used to prepare waterborne epoxy emulsion by phase inversion technique. The effect of the dosage of boron trifluoride （BF3） diethyl etherate as catalyst on the epoxy value of the reaction system with epoxy resin CYD011 and polyethylene glycol PEG6000 was discussed. The structure of emulsifier was characterized by infrared spectroscopy and gel permeation chromatography. The molar ratio of epoxy resin to PEG6000, mass fraction of emulsifier, emulsification temperature, and epoxy resins with various molecular weight on the performance of epoxy emulsion were studied. The results showed that a highly-stable emulsion with particle size 〈1μm can be obtained when the epoxy equivalent of epoxy resin is 450-500, emulsification temperature is 75 ℃, the dosage of catalyst is 0.40%, the molar ratio of epoxy resin to PEG6000 is 1：1, and the mass fraction of emulsifier is 15wt%. The film prepared from the emulsion features a flexibility of 1 mm and an impact strength of 50 kg.cm, and is able to endure corrosion in 5wt% NaC1 solution for 17 d and salt spray test for 480 h. The emulsion can be applied to heavy- duty anticorrosion coating.