UV固化硅溶胶改性水性聚丙烯酸酯木器涂料的制备

Synthesis of UV cured waterborne polyacrylate wood coatings modified by silica sol

用硅溶胶改性、紫外光固化构成的体系,弥补水性纯聚丙烯酸酯木器涂料力学性能不佳、硬度较低、固化速度较慢的缺陷。通过将具有环氧基团的KH-560硅溶胶引入带有活性羟基的水性聚丙烯酸酯乳液中,以提高水性聚丙烯酸酯膜的力学性能及附着力;进而通过调控功能性单体季戊四醇三丙烯酸酯(PETA)的添加量制得紫外光固化硅溶胶改性水性聚丙烯酸酯木器涂料。研究了不同水性聚丙烯酸酯乳液配方对漆膜、涂膜固化速度及性能的影响。结果表明:硅溶胶含量为10%、PETA含量为12%时,制备的硅溶胶改性水性聚丙烯酸酯分散体具有良好的贮存稳定性,且90d内无沉淀分层现象,乳液有效粒径为250nm,固含量达到44.98%,紫外光固化涂膜玻璃化转变温度为21.78℃,拉伸强度为21.98MPa,断裂伸长率为31.5%,凝胶率为92.62%,漆膜紫外光固化时间10s,硬度达到3H,附着力达到1级。与传统水性纯聚丙烯酸酯体系相比,紫外光固化硅溶胶改性聚丙烯酸酯体系制得的漆膜力学性能优异,硬度较高,固化速度明显提高。

Modified by silica sol,the UV cured waterborne pure polyacrylate(PA)wood coating was developed,which could address the drawbacks of traditional wood coatings,such as unsatisfactory mechanical properties,low hardness and slow curing rate.The mechanical properties and adhesion of waterborne polyacrylate film could be improved by introducing KH-560 silica sol with epoxy group into aqueous polyacrylate emulsion with active hydroxyl groups.Furthermore,the UV cured waterborne polyacrylate wood coatings modified by silica sol were synthesized by adjusting the loading of functional monomer pentaerythritol three acrylate(PETA).The effects of different waterborne polyacrylate emulsion formulations on the curing rate and properties of film were characterized.The results showed that the PA had good storage stability with no precipitation and delamination within 60 d with 10wt% silica sol and 12wt% PETA.The effective particle size of the emulsion was 250nm and the solid content reached 44.98%.The glass transition temperature of the UV cured coating was 21.78℃,the tensile strength was 21.98 MPa,the elongation at break was 31.5%and the gelation rate was 92.62%.The UV curing time,hardness and adhesion of the paint film were 10 s,3H and 1st grade,respectively.The UV cured waterborne polyacrylate film modified by silica sol had excellent mechanical properties,higher hardness and faster curing speed compared with the traditional waterborne pure polyacrylate system.With the improvement of people s consciousness of environmental protection and the progress of waterborne wood coatings preparation technology,solvent-based coatings with high VOC have been phased out.Waterborne coatings have become the mainstream trend in the development of wood coatings due to their less VOC and less pollution.The UV curing method can improve the curing speed of coatings,greatly improve production efficiency and reduce production costs in the factory production and processing,and waterborne coatings are the mainstream trend of environmental protection coatings.The UV curing waterborne wood coatings have good development prospects.Silica sol was added to traditional polyacrylate system and functional monomer PETA was added to make the coatings with good mechanical performance and hardness while maintaining very low VOCs.After the coating was cured rapidly under UV light,it can form high quality appearance and adapt to diversified products,thus solving the problems of the waterborne pure polyacrylate system,such as poor mechanical properties,low hardness and slow curing speed.