The Synthesis Of Waterborne Polyurethane And Its Application In Paint

Waterborne polyurethane resin is a novel environmental protection material.Its water solubility is based on introducing hydrophilic groups(carboxylic or sulfonic groups)into the molecular chain by using chain extender,and thus the polyurethane resin can be dissolved in water to translate into an aqueous resin.However,chain extender is small molecule,which is the hard segment of polyurethane resin.Generally,the hydrophilic group of the waterborne polyurethane resin prepared by this method distributes unevenly,and the particle's size of the prepared polyurethane resin usually is too large,and its stability and mechanical properties can not meet the requirements of application.In this dissertation,a hydrophilic small molecule acid containing cyclohexane structure was synthesized by catalytic hydrogenation which is based on the relationship between molecular structure and property.Also,A new type of sulfonic acid polyester polyol its was synthesized which contained it.Ulteriorly,the obtained sulfonic acid polyester polyol was introduced into the soft chain of polyurethane resin to prepare sulfonic acid waterborne polyurethane resin.Finally,the waterborne polyurethane paint with outstanding can be produced by using the designed sulfonic acid waterborne polyurethane resin.Experimental results:(1)The prepared hydrophilic small molecular acid has optimum conversion when the reaction temperature,pressure and time is 100?,5MPa,8h.and the solvent is DMF,respectively.(2)The prepared sulfonic acid polyester polyol possesses prominent properties when the hydrophilic group content is 8.5%,and the hydroxyl and acid values are 56±2 and 0.5±0.1,respectively.(3)The prepared waterborne polyurethane resin has excellent properties when the chain extension coefficient is 0.8,and polyol molecular weight is 3500,and using BDO as chain extender.(4)The waterborne polyurethane paint has optimum settlement rate,maximum adhesion strength and maximum salt spray time when the BYK193,FC4430 and seasoning content are 3.2%,0.6%and 6.5%,respectively.