| Water-based ink was free of volatile organic solvents, making it helpful in reducing volatile organic compound(VOC) discharging, therefore reduced air pollution and improved the working environment safety for print operators. Because of these advantages, water-based ink was applied more and more widely. At present, Medium and high grade water-based ink in china still relied on importation.Domestic water-based ink was not capable of being both film-form fast and glossiness high, directly affects its manufacturing cost and quality. It was of great economic and social value of doing research on water-based ink and its binders.In this thesis, acrylic emulsion was prepared using n-butyl acrylate (BA) and methyl methacrylate (MMA) as main monomers, allyloxy nonylphenol (10) ether sulfate (DNS-86) as emulsifiers and ammonium persulfate (APS) as initiator by pre-emulsification method.The influence of reaction conditions such as reaction temperature, emulsifier content and initiator content on the properties of the acrylic latex were investigated,the optimalizing reaction conditions was established as reaction temperaturebeing82±2℃, reaction time being about3-3.5h and the content of emulsifier and initiator being2.0%and0.4%respectively.In order to improve the performance of water-based binders, three different kinds of functional monomers were introduced, namely acrylic acid (AA), itaconic acid mono-butyl (MBI) and Di-(n-butyl) itaconate (DBI).By comparing the performance of latexs containing different functional monomers with different content,it was found that the latex prepared using DBI as function monomer showed the best performance such as the highest monomer conversion ratio,the smallest grain diameter and btter stablity. The dynamics of the emilsion polymerization which was tested showed that the polymerization rate of the emulsion containing DBI firstly entered the gently period. The results of tests showed that the latex membrane made from latex containg DBI exhibited excellent resistant ability to water, ethanol and heat, but medium resiatance to alkali and poor mechanical properties. Taking the comprehensive performance into consideration, the optimalizing content of DBI was1.5%. To improve the rate of latex film formation, a secondary functional monomer Diacetone acrylamide (DAAM) was introduced while using DBI as the primary functional monomer. The cross-linking reactions were confirmed by FT-IR tests; results of differential scanning calorimetry (DSC) revealed that the adding of DAAM led to the rise of the glass transition temperature of polyacrylate latexs. By comparing the performance of latexs with different DAAM content, it was found that the solid content and the monomer conversion rate improved after adding DAAM, and the stability of the latexs such as the freeze-thaw stability improved as well. Pictures from transmission electron microscope (TEM) showed that latex particle size became smaller after adding DAAM, and the latex particles sticked with eachother.The deposition rate of the emulsion added DAAM was significantly accelerated, and the heat and water resistant ability and mechanical properties of the latex film were all improved. Taking the comprehensive performance into consideration, the optimalizing dosage of DAAM was3%.Water-based inks were prepared with the content of AA being1.5%, content of MBI being1.5%, and content of DBI and DAAM being1.5%and3%respectively, and the properties of thewater-based inks were studied. Results showed that water-based inks made from latexs with different functional monomers all reached the standards of domestic enterprises, especially the the glossness of water-based ink with DAAM had been improved, thus solving the problem we have mentioned previously about water-based ink as not be capable of being both film-form fast and glossiness high. |
PDF Full Text Request