Preparation And Properties Of UV-Moisture Curable Hybrid Coating

The polymer thin film has many excellent optical properties and widely used in the fields of liquid crystal display, touch screen, household electrical appliances, medical apparatus, but its development speed is limited by the scratch resistance, refractive index and so on. The conventional organic coating also had exposed its shortcomings; however, hybrid organic–inorganic material had attracted many interests for its outstanding properties which came from organic and inorganic parts.In this study, UV-curing technology and sol-gel theory were combined to prepare organic–inorganic hybrid materials, namely UV-moisture method. For good compatibility with UV curable system, Ti(C4H9O)4 can well disperse into UVCC and UV-induced polymerization. Once Ti(C4H9O)4 contact with moisture and generate inorganic phase by hydrolysis, hybrid material that owns well dispersed inorganic phase, excellent optical and mechanical properties could be formed. Main researches in this paper as follows:(1) Parameters of Ti(C4H9O)4 hydrolysis were discussed, such as type and dosages of hydrolysis medium, acid value of monomers and orders of adding raw materials. Results showed that the medium of isopropanol/butanone(quality ratio 1:1) is the better medium to slow down the hydrolysis. The slower hydrolysis speed of Ti(C4H9O)4 could obtained in the higher system acid value and viscosity, for example, in PETA. The better way to slow down the hydrolysis like this: Firstly, blending Ti(C4H9O)4 with medium, then slowly adding UV curable components into the mixture.(2) Effects of orders of UV curing and moisture hydrolysis on material properties were studied. Results showed that curing orders had no influence on hardness and ductility. However, moisture hydrolysis followed by UV curing could enhance the scratch resistance and keep the transmittance unchanged.(3) Effects of UV curable components on material properties and acid values were researched and series of hybrid materials with different percentage of inorganic phase based on UV curable system were prepared by UV(free radical)-moisture method. SEM showed that a new phase was well distributed in the hybrid materials; FTIR, XRD indicated that the new phase was the amorphous TiO2 formed by hydrolysis of Ti(C4H9O)4; TG, DTG analysis suggested that the hybrid material had good thermal stability. When Ti(C4H9O)4(ωt%) was 17.47%, the hybrid material performed excellent optical and mechanical properties: haze was 0.61%, VL transmittance was 90%, gloss was 193 Gs and refractive index was 1.5555; Hardness was 2H, scratch resistance(ΔH/H0, 50/500 g) was 1.55%;(4) Effects of free radical or cationic curable system and the photo-initiator synergism with different mechanism on hybrid polymerization were studied. Based on these, the organic part of hybrid material was determined and series of hybrid materials with different percentage of inorganic phase were prepared by UV(free radical-cationic hybrid)-moisture method. SEM, FTIR, XRD, TG indicated that the inorganic phase was well dispersed in organic phase; When Ti(C4H9O) 4(ωt%) was 17.47%, the excellent optical and mechanical properties as follows: haze was 0.51%, VL transmittance was 90%, gloss was 191 Gs and refractive index was 1.5730; Hardness was 2H, scratch resistance(ΔH/H0, 100/500 g) was 1.99%.