Preparation And Properties Of UV One-component Photoinitiators And Amine-containing Resins

The radical polymerization of acrylate based on UV photopolymerization technology is rapid,making it widely used in coatings,printing inks,varnish and other fields.However the type of polymerization is susceptible to the inhibition of free radicals by oxygen molecules,which generally reduces the rate of polymerization and prolongs the exposure time,resulting in poor surface cure.In actual industrial production,the inhibition of oxygen is often alleviated by increasing the mass fraction of the photoinitiator or by adding a hydrogen donor such as amine,thiol or borane.However,amines and conventional photoinitiators have a relatively small molecular weight and are easy to migrate,and too much amine-assisted initiator can affect the hardness of the coating surface.Therefore,the development of new substances that can alleviate oxygen inhibition is still a research hotspot in the field of photocuring.The purpose of this thesis is to prepare and study one-component photoinitiators and amine-containing tetrafunctional urethane acrylates which can alleviate oxygen inhibition and reduce surface drying time.The main research contents and conclusions are as follows:1.A novel one-component photoinitiator(MAE-MBP)was prepared by introducing 2-methylaminoethanol(MAE)into the molecular structure of 4-methylbenzophenone(MBP).The structure,absorbance and migration of MBP and MAE-MBP were characterized by FTIR and UV-vis.The results showed that MAE was successfully grafted into the molecular structure of MBP.Compared with MBP,the maximum absorption peak wavelength of MAE-MBP did not change significantly,but the maximum absorption wavelength extended from 368 nm to 400 nm.the maximum absorbance increased from 0.268 to 0.845,and the migration decreased from 79.7%to 17.6%,which has good high absorbance and low migration.2.The MAE-MBP was applied to hyperbranched polyester acrylate coatings.The effects of light source power,mass fraction of photoinitiator and doping amount of aminated nano-silica(KH-550-SiO2)on surface dry time of photopolymerization system were discussed.The results showed that compared with MBP,when the light source power was 4W/cm2 and the photoinitiator mass fraction was 4%,the polymerization time of MAE-MBP initiation system was reduced from 13s to 10.5s.Increasing the light source power and photoinitiator mass fraction could reduce the surface dry time of the MAE-MBP photopolymerization system.When the MAE-MBP mass fraction exceeded 8%,the surface drying time tended to be gentle.The content of KH-550-SiO2 could alleviate the inhibition of oxygen on free radicals.When the content was 1.5%,the surface drying time could be reduced to 9.3s and the double bond conversion rate was 96.5%.3.An amine-containing tetrafunctional urethane acrylate(A-PUA)was synthesized by a double bond controllable method.The structure and thermal stability were characterized by di-n-butylamine detection,FTIR,1H NMR and TG.The results showed that there were no characteristic absorption peaks of-NCO in the prepared products,and characteristic peaks of groups such as-NHCOO-,-NHCON-,-C=C-appeared,which proved that A-PUA was successfully synthesized.The TG test showed that the decomposition temperature of A-PUA was divided into three stages of 100?300?,300?380? and 380?500?,which had certain thermal stability.4.The A-PUA resin solution was applied to dipropylene glycol diacrylate(DPGDA)and aliphatic difunctional urethane acrylate photocurable coating initiated by MBP,and a series of UV light curing coatings were prepared and cured to form a film.The effect of the mass fraction of A-PUA resin solution on the surface drying time,adhesion,flexibility and pencil hardness of the coating was investigated.The results showed that the surface drying time of the coating film is gradually shortened with the increase of the mass fraction of A-PUA resin solution.when the content of A-PUA resin solution was 40%,the adhesion of the coating film was grade 1,and the pencil hardness was 3H,which had good mechanical properties.The content of A-PUA resin solution had no significant effect on the flexibility of the coating film.