Study On Preparation And Properties Of Cationic Waterborne Polyurethane Finishing Agent

There is cationic group on the main or side chain of cationic waterborne polyurethane,which brings excellent function to cationic polyurethane.Cationic group makes sure waterborne polyurethane self-emulsify,at the same time it reduces water resistance.In this research,cationic waterborne polyurethane of good stability was prepared,at the same time the water resistance and softness of cationic waterborne polyurethane film were improved.In this research,elasticity,extensibility,weight gain rate,contact angle,TG,and structure of polyurethane had been tested and evaluated.At the same time,emulsion stabilities of polyurethane had been tested,including storage stability,high temperature stability,freeze-thaw stability,electrolyte stability,acid stability and dilution stability.Also particle size and its distribution were tested.Polyester and polyether polyurethane were synthesized in this paper,cationic waterborne polyurethane was modified respectively by different content of hydroxyl alkyl polysiloxane,self-made organosilicon compounds and monoglyceride stearic acid(GMS).Finally the effect of hydrophilic chain extender on waterborne polyurethane was studied.The test showed that the emulsion stability of polyester polyurethane was good,but the mechanical property,water resistance and water repellency were poor.The mechanical property and water resistance of polyether polyurethane film were good,but the high temperature stability,acid and alkali resistant,and water repellency of emulsion were poor.For synthesis of polyurethane,mixed soft segments of polyester(PE2348)and polyether(ZC330)were used,when m(PE2348):m(ZC330)is not less than 1:1,that helped to improve the emulsion stabilities,increased contact angle,decreased particle size.But the water resistance of film weakened when m(PE2348):m(ZC330)were increased and mechanical property was poorer.TG showed that the thermal stability became poor.Hydroxyl alkyl polysiloxane(PPC)modified polyester polyurethane that was against to properties,emulsion got yellower,water resistance and mechanical property were poorer.But when wt(PPC)is less than 11%,that was good for properties.Emulsion stabilities,water resistance,water repellent and softness were improved,but the mechanical properties were deteriorated.After self-made organosilicon compound modified polyurethane,softness and water resistance were improved,but mechanical property and emulsion stabilities were deteriorated.With 3% mass fraction of glycerol stearate modified polyurethane,film felt smooth,water resistance was improved,mechanical property was poorer.The water repellent of polyester polyurethane got better,but the emulsion stabilities became worse.The emulsion stabilities of polyether polyurethane got better and water repellent got worse.The introduction of hydrophilic chain extender(N120)can reduce the water resistance and water repellency of polyurethane.When the mass fraction of N-methyl diethanolamine(MDEA)was about 6% to 7%,the smallest particle size was 61 nm,and the water repellency was larger.The increase of MDEA content would reduce the water resistance of the film.