Preparation And Research Of Water-Soluble Unsaturated Polyester Resin

In recent years,with the improvement of people’s environmental protection awareness,low volatile organic coating was attracted more attention by people.Water-soluble unsaturated polyester resin with low curing temperature,good process performance,good electrical properties after curing,light weight,and low price advantages,was drawn much more attention.In this paper,the water soluble unsaturated polyester was synthesized with dibutyltin dilaurate as the catalyst,and mole ratio of alcohol and acid was 1.05:1.The resin with rather good water solubility was obtained with amount of isophthalic acid,maleic anhydride,dihydroxy methyl acrylic acid,trimethylolpropane.neopentyl glycol,and phthalic anhydride was 10 wt%,30 wt%.12 wt%.20 wt%,16 wt%,and 12 wt%of the total materials respectively.Then the water soluble paint was prepared with unsaturated polyester resin as matrix resin,ben/oyl peroxide as initiator,amount of N,N-dimethyl ethanolamine,styrene respectively was 8 wt%and 25 wt%of the weight of the unsaturated polyester resin and other additives,This paint was light yellow and transparent with pH value was 7.58.and viscosity was 34.5 s(23 ℃,No.4 Cup).When cured at room temperature,the surface of paint film was stick.However,after curing at 100 ℃,the paint film was smooth,and the hardness and adhesion grade of the paint film was respectively,4 11 and 1.The unsaturated polyester resin was modified by tung oil anhydride.Results showed that tung oil anhydride was synthesized with tung oil and maleic anhylride which quality ratio was 17:3 and reacted for 2.0 h at 150 C.The paint was prepared with modified unsaturated polyester resin as matrix resin.TPO as initiator styrene as the active diluents.With the amount of tung oil anhydride was 15 wt%of the weig,ht of unsaturated polyester resin,the liquid paint and paint film performance was best.The paint was completely soluble in water,which pH value was 8.15,viscosity was 34.8 s(23 C,No.4 Cup),and gel time,surface drying time and hard drying time was respectively 18 min,14 min and 17 h,and the hardness of the paint film was 2 H,adhesion grade was 1,after curing at room temperture.Investigation on the structures of modified resin by FT-IR indicated that some conjugated carbon carbon double bonds and rigid six-member ring groups were introduced into the molecular structures of resin after modifed,which improved the air drying and heat resistant properties of the modified resin and let it are more suitable for coating at room temperature.