Preparation Of Odorless UV-curable Coating

UV-curable coatings are environmentally friendly. They have properties of low energy consumption, low economic efficiency and excellent product performance, etc., which have great technical advantages and development potential in nowadays society. Because of the active group in reactive monomer, reactive resins can be involved into polymeric curing reaction, thus the VOC of UV-curable coatings are much less than that of the traditional solvent-based coatings. However, there are still some volatile components in UV-curable coatings, such as the residual resin, residual reactive monomer or reaction products of photoinitiator. In this thesis, the optimum formulation of odorless UV-curable coatings was researched and determined by the orthogonal test, which used the UV-curable resin, modified photoinitiator and reactive monomer as the main factors, respectively and VOC, odor of coating, and film performance as the experimental indexs, respectively.The low odor macromolecule photoinitiator was prepared by the modification of isocyanate prepolymesr on α-hydroxyketone photoinitiator(1173, 184, and 2959). It was found that the modified 184 showed the highest initiator efficiency.when the used amount percentaege was 3% and the final conversion is above 90%.The effect of irradiation time, light intensity, concentration of modified photoinitiator on kinetic behavior of modified photoinitiator was studied by real-time FTIR spectroscopy and real-time UV-vis spectroscopy. It was found that the conversion increased rapidly at first and became flat lately, while the rate of polymerization decreased with the increasing radiation time. At a higher light intensity, the conversions of double bones are higher in the same radiation time. It was also observed that kinetic behavior of modified photoinitiator 1173 conforms to formula:-d[I]/dt= 2.48[I]1.59, which referred that kinetic behavior of modified photoinitiator confirmed with 1.59 th dynamic model.UV-curable coatings were prepared by the modified photoinitiator, resins, reactive monomers and additives. The effect of the kinds of resins, ratio of resins, combination of photoinitiators, amount of photoinitiators on VOC, odor of coating and properties of film were studied. The optimum formulation of odorless UV-curable coatings was researched and determined by single factor experiments and orthogonal test: the ratio of polyester acrylic resins and polyurethane acrylate resin was 4:1, TPGDA22%, EO-TMPTA7%, and modified photoinitiator 2%. The film shows good performances as follows:VOC of coating and paint film was 4.01% and 0.43% respectively. The hardness of film was 2H and the adhesion was 1 grade. The impact resistance of film was 45 cm ans had good solvent resistance.By the method of the preparation of macromolecule modified photoinitiator and optimization of formulation, aims were almost obtained in order to solve the VOC and odor problem caused by the residual resins, reactive monomers or reaction products of photoinitiators. The odorless UV-curable coatings not only had low VOC but also had excellent film performance, which would have a wide applicate prospect.