METHOD FOR PRODUCING EPOXY VISCOUS AGENT FOR CATIONIC ELECTRO-DEPOSITION COATING

To provide a method for producing an epoxy viscous agent for cationic electro-deposition coating, and a cationic electro-deposition coating composition which contains the viscous agent and improves edge corrosion prevention.SOLUTION: A method for producing an epoxy viscous agent for cationic electro-deposition coating includes: (1) an amine modification step of reacting a chain extension epoxy resin, which is obtained by chain extension of a polyphenol polyglycidyl ether type epoxy resin and has a ratio of a relative molecular weight of 100,000 or more by gel permeation chromatography (GPC) of 13.0-18.0 mass%, with an amine compound, and obtaining an amine-modified epoxy resin; (2) a dispersion step of neutralizing a part or all of amino groups of the obtained amine-modified epoxy resin with an acid, and dispersing the neutralized amino groups in a water solvent; and (3) a high molecular weight step of mixing and reacting the obtained dispersion with the polyphenol polyglycidyl ether type epoxy resin, and obtaining an epoxy viscous agent. A cationic electro-deposition coating composition contains the same.SELECTED DRAWING: Figure 1 【課題】カチオン電着塗料用エポキシ粘性剤の製造方法、及び該粘性剤を含む、エッジ防食性が向上したカチオン電着塗料組成物の提供。【解決手段】（１）ポリフェノールポリグリシジルエーテル型エポキシ樹脂を鎖延長して得られた、ゲルパーミエーションクロマトグラフィ（ＧＰＣ）による相対分子量１０万以上のものの比率１３．０〜１８．０質量％を有する鎖延長エポキシ樹脂と、アミン化合物とを反応させて、アミン変性エポキシ樹脂を得る、アミン変性工程、（２）得られたアミン変性エポキシ樹脂が有するアミノ基の一部または全てを酸で中和し、水溶媒中に分散させる、分散工程、および（３）得られた分散物と、ポリフェノールポリグリシジルエーテル型エポキシ樹脂とを混合して反応させて、エポキシ粘性剤を得る、高分子量化工程、を包含するカチオン電着塗料用エポキシ粘性剤の製造方法。また、それを含むカチオン電着塗料組成物も提供する。【選択図】図１