Preparation And Characterization Of Functional Coating Materials On Glass Surface

As a keysafety component,vehicle glass is required to be multi-functional as well as safety-ensuring.In recent years,heat insulation,antifogging,hydrophobicity,and head-up display(HUD)have become the main directions of automotive glass's functionalization.Heat insulation can be achieved through both absorption and reflection.Light absorption,however,increases the temperature of sheltered objects and leads to secondary radiation effect,which brings in turn a new heat source.Therefore,heat-reflecting materials have been gaining more and more attention in heat insulation studies.On the other hand,despite anti-fogging function can be achieved by air-conditioning for windshield glass and by electricity-heating for rear window glass,automotive anti-fogging for side windows are still hard to realize.Among all antifogging materials,the water-absorbing one is a hot spot.This study was set in a background of coating on automotive glass's surface,and two kinds of functional materials were prepared and characterized:(1)nanoparticles with high near-infared(NIR)light reflectance for heat insulation application,(2)water-absorbing micro-films for antifogging application.In this study,NiTiO3 nanopowders with a reflectance of NIR higher than the one of visible light,along with Bi2Ti2O7nano powders whose reflecting property was better than the one of commercial TiO2(ST-01)were prepared by sol-gel method by using citric acid as a catalyst and tetrabutyl titanate(TBT)as Ti source.The obtained titanate nano powders were modified via surfacial Ag-wrapping,followed by characterizations of XRD patterns,SEM images,and UV-visible-NIR spectra.Results show that 1.5ml 2wt%AgNO3 added causes an extremely high NIR reflectance(60.24%),while with low visible light reflectance(13.88%).Additionally,powders can be well-dispersed in water with PEG 1000 as the dispersant after ball-milling process.In this study,two-layer structure was applied in water-absorbing antifogging films,and synthesis process of the films was studied.Exploration focused on impacts of under-coating thickness and coating processes on surfacial conditions of the films,as well as effects of curing agents and the number of epoxy resin's groups on antifogging properties and yellowing index.Results show that when the number of epoxy resin's groups increases from 2.5(EX313)to 6.3(EX521),there are more knots in the obtained three-dimension network through cross-linking and the space inside the network is less,which thereby contributes to a shortened antifogging time.On the other hand,because of without free amine,acid-anhydride-solidified water-absorbing antifogging films consequently givea better yellowing indexes than the amine-solidified ones.