Preparation And Application Of Wear-Resistant Waterborne Polyurethane Matting Resin

Although the new self-matting waterborne polyurethane(WPU)has solved the problems of poor compatibility,increased brittleness and precipitation of the matting agent caused by the matting agent,its coating film has poor wear resistance and scratch resistance,which limits its wide range application.Therefore,it is of great significance to prepare WPU coatings with excellent matting properties and abrasion resistance.In this study,by adjusting the crosslinking degree and microphase separation of WPU,the wear resistance of self-matting WPU was improved.Two kinds of organic silicon,hydroxyl terminated polydimethylsiloxane(PDMS)and N-2-aminoethyl-3-aminopropyltrimethoxysilane(KH-792)were introduced to reduce the surface energy of WPU,increase the crosslinking degree,and further improve the wear resistance of WPU.Firstly,three types of polymer polyols(Polytetramethylene ether glycol,Polycarbonate diol and Poly(neopentyl glycol adipate)),isophorone diisocyanate(IPDI),dimethylolpropionic acid(DMPA),crosslinking agent trimethylolpropane(TMP)and neutralizing agent triethylamine(TEA)are used to prepare prepolymer,and then hydrazine hydrate is used as the post-chain extender to prepare WPU matting resin.Use infrared spectroscopy,gloss meter,TABER abrasion tester,environmental scanning electron microscope(SEM),thermogravimetric analyzer,universal testing machine,atomic force microscope,3D optical profiler to characterize and analyze the performance of emulsion and coating.The effects of different polymer polyol types,R value and TMP content on the properties of WPU emulsion and coating film were discussed.The results show that the infrared spectrum shows that WPU has been successfully synthesized,and the WPU prepared with polycarbonate diol as the soft segment has the best overall performance.AFM,SEM and 3D optical profile instrument show rough microstructure on the surface of the film.When R value is 1.5 and TMP content is 0.9wt%,the surface gloss of the coating reaches flat level,and the wear resistance is the best.Secondly,PDMS and KH-792 were introduced into the WPU molecular chain by chemical copolymerization to further improve the wear resistance of WPU.Use infrared spectroscopy,gloss meter,TABER abrasion tester,SEM,thermogravimetric analyzer,3D optical profiler,surface contact angle tester to characterize and analyze the properties of emulsion and coating film.The effects of PDMS molecular weight,PDMS content,DMPA content and KH-792 content on the properties of WPU emulsion and coating film were investigated.The results show that: infrared spectroscopy proves that PDMS was successfully introduced into the WPU molecular chain.When the molecular weight of PDMS is 1000,the content of PDMS is 6 wt%,the content of DMPA is 2.2 wt%,and the content of KH-792 is 40mol%,the surface gloss of the coating reaches flat level,and the wear resistance is excellent.Finally,homemade WPU-A3,WPU-B2,WPU-K1 and WPU-K2 were formulated into WPU coatings,which were applied to PVC and PU synthetic leather,and compared with the two matting coatings WR-8394 A and Stahl-549 on the market.The differences in surface morphology,matting properties,abrasion resistance,water absorption,blocking resistance,rubbing resistance,folding fastness,rubbing fastness and adhesion of different coatings are discussed.The results show that the wear resistance of WR-8394 A is the worst,and the wear resistance of WPU-K2 is second only to Stahl-549,other properties are similar to Stahl-549.