The Research On Preparation Of Derivative And Modification Of Unsaturated Polyester Resin By Tung Oil

Tung oil is a unique woody oil crops in our country, which is the main product of tung and mainly used in coating field. However, tung oil cannot be embedded into the polymer chain directly and compatible with the polymer poorly, therefore, the development of a new type of tung oil derivatives which are applied to the modification of unsaturated polyester resin (UPR) are meaningful. It not only can improve the compatibility with the reactants and improve the UPR in water resistance, solvent resistance, heat resistance and mechanical properties, etc, but also can improve the added value of tung oil and promote the development of tung processing industry.This paper studied the process conditions of preparation of eleostearic acid (EA) by solvent saponification acidification with tung oil as raw material; With tung oil derivatives-methyl-a-eleostearate as a raw material, synthesized the epoxidation methyl-a-eleostearate (EME) by solvent-free resin catalysis; And tung oil derivatives-EA, EME, eleostearic acid monoglycerides (EAM), methyl-a-eleostearate-maleic anhydride adduct (MEMAA) and tung oil anhydride ester polyol (TOAEP) were used in the modification of UPR respectively, the results obtained EA-UPR、EME-UPR、 EAM-UPR、MEMAA-UPR and TOAEP-UPR modified resin, which have excellent performance of coating. The main results are as follows:1. The appropriate conditions of preparation of eleostearic acid by tung oil are mole ratio of tung oil to KOH1:3.5, saponification reaction time1.5h, saponification reaction temperature75℃, oil-water ratio1:12and mole ratio of alcohol to water in mixed solvent2:1. Under the optimal conditions, eleostearic acid’s yield is98.2%, with acid value199.8mg KOH/g.2. The appropriate conditions of synthesis of epoxidation methyl-a-eleostearate (EME) are as follows:the suitable catalyst for the reaction is sulfonic acid resin, the quality of EME is5%for ME, material than of n (ME):n (H2O2):n (CH3COOH) is1:5:2.5, reaction time is3h, reaction temperature is65℃. Under the optimal conditions, EME’s epoxy value is5.2%. Sulfonic acid resin can be reused for3times and still maintaining high catalytic activity.3. The results of tung oil derivatives modified unsaturated polyester resin are as follows:the five kinds of tung oil derivatives of UPR coating in hardness and adhesion are improved, and the influence degree do not have obvious difference; The MEMAA is the best choice to improve the UPR coating in water resistance, solvent resistance and heat resistance, and appropriate MEMAA content is9%. At the same time, the EA is the best choice to improve the UPR coating in flexibility, tensile strength and impact resistance, and appropriate EA content is9%.In the thesis, a kind of tung oil derivatives and modification of unsaturated polyester resin were synthetised (the high acid value in eleostearic acid, epoxy value of epoxidation methyl-a-eleostearate), their performances can meet the basic requirements of modified resin film coating resin. It provides a theoretical guidance to expand the application range of the tung oil.