Preparation And Application Of Epoxy Acrylate Modified By ?-caprolactone

In the production and usage of traditional coatings,a large number of volatile organic compounds(VOC)was discharged,leading to the significant environmental pollution.Compared with traditional coating,UV-curable coating has the advantages of environmental protection,energy saving,widely adaptability,economy and efficiency,leading to the wide application in wood,plastic and printing field.Bisphenol A epoxy acrylate(EA)has the advantages of fast curing rate,mechanical strength,excellent chemical resistance and other characteristics,so its dosage has accounted for 80%of the total UV oligomers.But the flexibility and adhesion of UV-curable coating is poor,so the application of EA in the metal field is greatly limited.Poly(?-caprolactone)(PCL),obtained from the ring-opening of?-caprolactone(?-CL),has the advantage of adjustable molecular weight,excellent toughness and adjustable functional group.In this work,a series of modified epoxy acrylate were prepared with the modification of?-CL and their applications in UV metallic coatings were also investigated.In the first part of this thesis,a series of PCL modified epoxy acrylate(EA*)was prepared by introducing flexible chain segment into the main chain of EA resin using AA-PCL with photosensitive group as the modifier.The optimal synthesis process of EA*was investigated carefully.The structure of EA*was characterized by Fourier Infrared spectroscopy(FTIR),proton nuclear magnetic resonance spectroscopy(~1H-NMR)and gel permeation chromatography(GPC).The UV curing coating was prepared using EA*as main resin and the basic properties,mechanical properties,thermal mechanical properties of the curable coating were discussed.The results showed that,the properties,adhesion and salt spray resistance of EA*coatings enhanced compared with commercial EA.Moreover,the viscosity of the system gradually decreased with the content of AA-PCL modifier.When the content of AA-PCL was57.5%,the viscosity of the system was 80 Pa.s,which decreased by 80%compared with the commercial EA system.In the second part of this thesis,with the modification by?-CL and IPDI,flexible long carbon chain as well as amide group were introduced into the side chain of commercial EA resin,leading to the successful preparation of EA*-PUA,improving the toughness and adhesion of the coating.The structure of EA*-PUA was verified by NCO,FT-IR,~1H-NMR,and GPC.Compared with the commercial EA,the coating properties of EA*-PUA,such as gloss,hardness,flexibility and adhesion,has been significantly enhanced owing to the co-existence of flexible long carbon chain and amide group in the EA*-PUA.At the same time,when the molar ratio of?-CL:EA was 3:1,the elongation at break of the curing film could reach 7.23%,which was60%higher than that of the pure EA.In the third part of this thesis,the EA*-PUA resin was chosen as the main resin of the primer to expand the application of UV metallic coating,the optimal formula of the primer was determined through single factor analysis method.Moreover,EA*resin was used to prepare metal finish coating,the formula of which was selected by orthogonal test.It was found that the basic properties of UV metallic primer and UV metallic finish could meet the requirement of traditional solvent metal coatings.