Preparation And Properties Of High Performance Waterborne Polyurethane Fabric Coating

Waterborne polyurethane is a new environmentally friendly material that can be used in various aspects of the textile industry.It exhibits excellent performance in wrinkle resistance,water and oil resistance,flame retardancy,and breathability.At present,there are few single component self-crosslinking waterborne polyurethane products in the field of fabric coating,and their performance is closely related to the isocyanate raw materials and small molecule chain extenders used.Therefore,the influence of the types and amounts of isocyanates and chain extenders on the performance of the prepared waterborne polyurethane is studied,and the structure-activity relationship is analyzed,It is of great significance to screen the types and amounts of isocyanates and chain extenders with the best performance to synthesize a highperformance single component self-crosslinking waterborne polyurethane.Firstly,polytetrahydrofuran ether glycol(PTMEG2000)was used as the soft segment,followed by the addition of hydrophilic chain extender dimethylpropanoic acid(DMPA),salt forming agent triethylamine(TEA),and chain extender ethylenediamine(EDA).Five different isocyanates were used: isophorone diisocyanate(IPDI),toluene diisocyanate(TDI),4,4’diphenylmethane diisocyanate(MDI),and dicyclohexylmethane diisocyanate(HMDI)Hexamethylene diisocyanate(HDI)was used to prepare waterborne polyurethane with five different isocyanates through a prepolymer method.Through the analysis and research on the performance of waterborne polyurethane lotion,film performance and application performance,it is found that the waterborne polyurethane prepared with IPDI as the raw material has the best performance,the average particle size is 210 nm,and the viscosity is 1525 cps;The elongation at break of the adhesive film reaches 520.13%,the breaking strength is 36.55 MPa,and it has good thermal stability;After washing,the fabric coating only showed slight blistering,with a dry rubbing color fastness of level 4 and a wet rubbing color fastness of level 5.The effect of IPDI dosage on the application performance of waterborne polyurethane fabric coatings was investigated,and it was found that the fabric coating had the best performance when the dosage was 30 wt.%.Using isophorone diisocyanate(IPDI)and polytetrahydrofuran ether glycol(PTMEG2000)as monomers,adding hydrophilic chain extender dimethylpropanoic acid(DMPA)and salt forming agent triethylamine(TEA),five different post chain extenders were used:ethylenediamine,hydroxyethylenediamine,hydrazine hydrate,sebacic hydrazide,and mphenylenediamine.Five different post chain extenders of waterborne polyurethane were prepared by prepolymerization method.Through the analysis and research on the properties of waterborne polyurethane lotion,film properties and application properties,it is found that the waterborne polyurethane with sebacic hydrazide chain extension has the best performance,the average particle size of lotion is 272 nm,and the viscosity is 1045 cps;The elongation at break of the adhesive film reaches 602.64%,the breaking strength reaches 54.23 MPa,and the thermal stability of the adhesive film is good;The water washing resistance is qualified,and the color fastness to dry and wet friction reaches level 5.The performance is better than that of waterbased polyurethane fabric coatings with chain extension after using ethylenediamine,hydroxyethylenediamine,hydrazine hydrate,and m-phenylenediamine.The effect of the amount of sebacic hydrazide on the application performance of waterborne polyurethane fabric coatings was investigated.It was found that the fabric coating had the best performance when the amount was 1.6 wt.%.