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In order to improve the shortcoming of non-solvent and solvent insulation paint, meet the environmental requirements, and make full use of tung oil resources, waterborne alkyd-amino insulation paint modified by tung oil was prepared.Waterborne alkyd resin modified by tung oil was prepared by molten fatty acid method from tung oil, maleic anhydride, phthalic anhydride, adipic acid, lauric acid, trimethylolpropane. The effects of reaction time, reaction temperature, polyols and neutralizer on the water solubility, stability of waterborne alkyd resin modified by tung oil was studied; variation of acid value with time, effect of solvent on the resin viscosity were also studied. The results show that Diels-Alder reaction occurred between the conjugated double bonds of tung oil and maleic anhydride. The optimal synthesis conditions of the resin was obtained as following: reaction temperature and time were 190℃and 2 ~ 3h respectively in the first esterification stage, reaction wa, final acid value of resin was 50 ~ 60mgKOH/g.With HMMM as cross-linked agent, waterborne alkyd-amino insulation paint modified by tung oil was prepared. Effects of oil length, alcohol surplus and final acid value etc. of waterborne alkyd resin modified by tung oil on the properties of the insulation paint were studied, such as electrical strength, water absorption, heat resistance and so on. The structure and properties of the insulation paint were characterized and tested by FTIR, DSC, TG, and SEM. With the increase of oil length, water absorption of the film reduces, while electrical strength increases, but water-dispersible was bad, the ideal oil length was 37%; Tg and T20000 of the film increase with the increases of HMMM content; When HMMM content was 30%, Tg was 42.0℃and T20000 was 151.4℃; the increase of the heat resistance was not obvious when HMMM content was more than 30%, for the film cured more completely. Hardness, adhesion, water absorption and electrical strength testing results indicate the electrical strength of the insulation paint is more than 80MV/m, it processes good general properties and meet the requirement of actual application.
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