Preparation Of Waterborne Polyurethane Acrylate Emulsion Modified By Silane And Application For Wood-ware Coatings

Wood products,which play an indispensable role in human life,relate in all aspects of life.Wood-ware protection research is derived from the destruction of woodwork by environment and human.With the improvement of environmental protection policies and the continuous improvement of people's health awareness,waterborne coatings for wood products have become a hot research area.Firstly,a waterborne polyurethane emulsion(WPU)with double bonds ending was synthesized by isophorone diisocyanate,toluene diisocyanate,polyether diol,dimethylpropionic acid,1,4-butanediol,and hydroxyethyl acrylate as raw materials.Secondly,waterborne polyurethane emulsion,methyl methacrylate,butyl acrylate,and hydroxyethyl acrylate were selected as raw materials to prepare waterborne polyurethane acrylate emulsion(WPUA)by emulsion polymerization.Then,different cross-linking agents,N,N-methylene bisacrylamide,or trimethylolpropane triacrylate was chose to synthesize crosslinking modified waterborne polyurethane acrylate emulsion(TWPUA).Next,selecting different silane coupling-agents ?-methacryloxypropyl trimethoxyl silane or vinyltri(?-methoxyethoxy)silane to reached the second emulsion(SWPUA).Finally,two synthesized emulsions were blended to compare with commercial waterborne wood-ware coatings.Thermogravimetric analyzer,differential scanning calorimeter,particle size analyzer,universal tensile testing machine,and other analytical instruments were used to characterize the emulsion and film properties.The drying time,water contact angle,hardness,adhesion,and medium resistance of the preparing film were compared and the optimum addition ratio of each key component in the emulsion was obtained.The conclusion showed that dimethylol propionic acid was 5.0% of the formula mass,the mass ratio of waterborne polyurethane emulsion to acrylate monomer was 0.5,the addition amount of trimethylolpropane triacrylate was 2.0% of the total mass of acrylate monomer,the addition amount of vinyltri(?-methoxy ethoxy)silane was 10% of the total mass of acrylate monomer.Finally,the optimized waterborne polyurethane acrylate emulsion modified by silane was prepared and compared with the commercial waterborne wood-ware coatings.The hardness reached 2 H and the water contact angle reached100°,which was better than those of the commercial products.