Preparation And Performance Of Two-Component Waterborne Polyurethane Wood Coatings

Waterborne wood coating is a kind of coating with water as the dispersion medium.It has the advantages of low VOC content and high safety.At present,two-component polyurethane dispersions and self-crosslinking acrylic emulsions are popular for research and in order to improve their emulsions and coatings.Membrane performance can be modified to improve its performance.In this dissertation,a series of water-borne polyurethane(WPU)emulsions were prepared with diisocyanate,polyether diols and polyester diols,hydrophilic chain extenders(DMPA)small molecule chain extenders(TMP),and initial R was studied.The effect of(-NCO/-OH)value,DMPA content,and TMP content on the performance of the prepared polyether WPU emulsion and the coating film to determine the optimum raw material ratio for the preparation of non-modified WPU,and then in the best raw materials Based on the ratio,the epoxy resin(EP)was introduced to modify it,and then the effect of EP type and amount on the properties of the modified WPU emulsion and coating film was studied;the composite polyurethane was the basis of the optimal polyether type WPU.The introduction of polyesterol was investigated to investigate the influence of the amount of polyesterol on the unmodified composite polyurethane,and the polyether/polyester composite waterborne polyurethane with the best performance was prepared and introduced into the composite polyurethane core with the best performance.The EP was modified to explore the effect of the type and amount of EP on the properties of the composite emulsion.The main raw materials for the synthesis of the modified acrylic emulsion were organic silicon and small molecule polyols.The modification of the silicone was introduced into acrylic acid by means of emulsion polymerization.In the chain,Small molecule-modified polyol is introduced in the form of a core-shell acrylic emulsion package,and explored silicone,polyol,but the ratio of raw materials and their impact on the film properties of the acrylic emulsion synthesized.The study shows that when the R value is 2.3 and the amount of DMPA is 8.5%,the prepared WPU emulsion and coating performance is better when the amount of TMP is 4%.The addition of PBA can improve the mechanical properties of the polyether polyurethane.Preparation of composite waterborne polyurethanes with even better performance;theintroduction of epoxy resin increases the thermal decomposition temperature of the coating,and enhances the mechanical strength and water resistance of the coating.Epoxy E-20 has better overall performance than E-44 modified WPU.When the amount of E-20 added in the polyether WPU synthesis is 10%,when the amount of E-44 added is 5%,in the modification of the polyether/polyester composite WPU,PBA is 15%,E-20 At 8%,when the amount of E-44-modified WPU added was 4%,the modified emulsion and coating had better water resistance and mechanical properties.Infrared spectroscopy also showed that EP had been grafted into polyurethane and a ring-opening reaction occurred.In the synthesis of modified acrylic acid,semi-continuous dropping was used,the reaction time was 3.5 h,the initiator was 2%,and the composite emulsifier was used 3%,chain transfer agent 1.5%,silicone 4%,TMP 2%,modified acrylic emulsion has improved performance compared to unmodified before;modified by pure acrylic emulsion and silicone/TMP The analysis of the IR spectra of the aqueous acrylic emulsion shows that the silicone participates in the free radical copolymerization of the emulsion monomer and the mechanical property is significantly increased.