Study On The Preparation Of Water-soluble Alkyd Resin

Water-soluble alkyd resin is a polymer which is obtained through the condensation reaction by polyol, multiple acids and fatty acids as the main raw materials. Due to the usage of water as its solvent, water-soluble alkyd resin contains lower volatile organic compounds (VOC) than other resin using organic materials as solvent, and it can greatly reduce the harm to the environment and effectively protect the people's health. Therefore, the study on the theory and technology of water-soluble alkyd resin had important significance.In this paper, the water-soluble alkyd resin was synthesis through the melting fatty acid process and salt forming method. The alkyd resin constant (K), oil length (OL), alcohol surplus (r) were choosed as the main parameters of calculating alkyd resin formula. Moreover, the effects of experimental materials, acid value, oil degrees, alcohol excess, and other factors on the properties and resin film were carefully investigated. The optimum conditions on synthesis of water-soluble alkyd resin were obtained: OL=40%, r=0.20 and acid value was 40~50mgKOH/g, K=1~1.05. The experimental materials of synthesis water-soluble alkyd resin were linseed oil fatty acid, trimethylol propane, phthalic anhydride, trimellitic anhydride and maleic anhydride, ethylene glycol butyl ether as a cosolvent, dimethyl ethanolamine as neutralizer. When Phthalic anhydride: trimellitic anhydride: Maleic anhydride was 1:0.125:0.167(molar ratio) by the experimental analysis, the comprehensive performance of water-soluble alkyd resin was good. The finalized physical properties of synthesized water-soluble alkyd resin products were listed as below: it was the brown transparent liquid with the solid content was 75.8%, the viscosity was 1700s and the water solubility was more than 100 times. Moreover, the adhesion of resin film was 1, hardness was 4H, supple and water-resistant were also good.In the last part of this research, the rosin and amino resin were used to modify the water-soluble alkyd resin in order to improve the thermal stability and some other properties. Results indicated that the thermal decomposition temperature of rosin-modified water-soluble alkyd resin was exactly higher than pure water-soluble alkyd resin's. When Rosin: fatty acid was 0.167 (molar ratio), the viscosity of resin was the lowest, and the flow leveling and luster were the best. When adding the amount of amino resin was 20 ~ 25% of alkyd resin, the gel time of water-soluble alkyd resin was 80s at 210℃, the water solubility and stability of water-soluble alkyd resin were better. The adhesion of resin film was 1, hardness was 4H, supple and water-resistant is also good. The Water resistance and flexibility of resin film were also good.