A Study Of Synthesize And Modified Waterborn Polyurethane

In the environmental protection request strictly today, Waterborne polyurethane as a green polymer material with the features of no environmental pollution, excellent wear resistance, acid proof alkaline, non flammable, excellent adhesion, which is appreciated more and more attention today. But the introduction of the hydrophilic chain extender during its preparation results in poor performance such as water resistance of the adhesive film. To Improve the water resistance of waterborne polyurethane film has become the current development tendency. Adding other modified material to waterborne polyurethane material can increase the degree of crosslinking, which improves the properties of waterborne polyurethane.In this paper, toluene diisocynate (TDI) and polyester dihydric alcohol (PBA) as comonomer, dimethylolpropionic acid (DMPA) and1,4-butanediol (BDO) considered as the chain extender, trimethylolpropane (TMP) and triethylamine (TEA) used as the cross-linking agent and salt-forming agent respectively are used to prepare preparepolyester type waterborne polyurethane emulsion. The paper studies the influence of reaction temperature and reaction time on NCO conversion rate and the influence of trimethylolpropane (TMP), dimethylolpropionic acid (DMPA), carbimide and NCO/OH on the water resistance, stability and mechanical properties of the waterborne polyurethane. The results show that when the reaction temperature for prepoloymer and chain extension of preparepolyester type waterborne polyurethane is75℃-80℃, time is2.5h, R (NCO/OH)=2, the content of DMPA is4%, and added40%TMP can prepare the aqueous polyurethane with best performance.The paper studies the influence of-NCO/OH on tensile strength, water resistance and viscosity of the adhesive film on polyester and polyether type waterborne polyurethane sytheticed by PBA and polyether glycol (N220), at the same time compared their performance. The results show that polyester type waterborne polyurethane has poorer water resistance as well as flexibility and better mechanical performance than polyether waterborne polyurethane.In order to improve the performance of waterborne polyurethane, y-aminopropyl triethoxy silane (KH-550) was used to prepare the modified waterborne polyurethane. And in this paper the experiment was first neutralized, and then added the modifying agent KH-550to synthetize organosilicone modified waterborne polyurethane. At the same time, it also discussed the influence on dosage of KH-550on appearance, performance of modified waterborne polyurethane emulsion as well as the water resistance, viscosity and mechanical performance of the adhesive film. The results show that water resistance and mechanical property of the adhesive film of the polyurethane when modified by KH-550are obviously improved, and when KH-550content reaches6%, the performance of the polyurethane emulsion prepared is best.