Preparation And Property Of Two-Component Waterborne Polyurethane Transparent Coatings Modified By Silicon Oxide For Wood Substrate

It will be a further trend of using water borne coatings instead of traditional coati ngs,However,a water borne coating itself shows some difference compared with the trad itional coatings. Hence,the modification of the water-based coating has been a focus.In this paper,Silicon sol,POSS,Nanosilica dioxide were used to modify waterborne two-componen t polyurethane coatings, respectively in order to improve the heat resistance,mechanical str ength and water resistance of coating.Using the γ-(2,3-glycidoxypropyl) trimethoxysilane as the feedstock,a sol-gel meth od was used to prepare silica sol by adjusting the different volume and Two-component waterborne polyurethane (2K WB-PURs).The physical and chemical reaction,microstruct ure and transmittance properties was characterized using the IR,SEM and double beam U V visible spectrophotometer,respectively.The results showed that the as-prepared sol impr oved the hardness,wear resistance of the coating and anti-ultraviolet ability,while decrease d the adhesion and water resistance of the coatings.The incompletely condensed hepta (i-butyl) octasilsesquioxane (T7) was synthesize d by the controlled hydrolysis-condensation with isobutyltrimethoxysilane,The poss with single active group was prepared using the 3- aminopropyl triethoxysilane through the v ertex-cap method.And a series of waterborne curing agents were fabricated using the MPEG, POSS and HDI trimer as raw material. The effects of molecular weight of MPE G and NCO/OH on the dispersion of waterborne curing agent were studied.The physical and chemical reaction was analyzed by the IR.The effects of different volume of POSS on thermal properties,transmittance, water resistance,and mechanical properties were studi ed using the thermogravimetric,double beam UV visible spectrophotometer,XRD and conta ct angle.The results showed that POSS was evenly distributed in the coating,the contact a ngle of coating water,heatresistance, hardness, wear resistance were improved, while the a dhesion was decreased. In addition,the nano-SiO2 was used to modify and the effects of the amount of SiO2 on film performance were studied.