The Preparation Of Acrylic-polyurethane Adhesive For Pigment Printing And Study On Clogging Mesh Prevent

The pure polyacrylic emulsion binder was widely applied in pigment printing industrybecause of its fine water resistance, chemical resistance and low cost. However, it often cloggsscreen easily for its structure defect. Waterborne polyurethane has many advantages such asgood flexibility and large bond strength. So introducing polyurethane into acrylate system tocompose the core-shell structure emulsion, not only could contain the advantages of both of them,but also inprove the disadvantage of screen clogging of pure polyacrylic emulsion.In this paper, core-shell type polyacrylic-urethane emulsion adhesive was prepared aftersynthesis of polyurethane seed emulsion. And application performance of the adhesive in cottonpigment printing was evaluated and analyzed. In addition, the relation between film formationrate, dehydration rate of adhesive and screen clogging effect was explored. The research contentsand results include:1. The synthesis of polyurethane seed emulsion. Acrylate mixed monomers were added intopolyurethane seeded emulsion, core-shell type acrylic-polyurethane emulsion was prepared usingseed emulsion polymerization. The molecular structure and core-shell structure were confirmedrespectively by ATR-IR and TEM; The TGA analysis of film proved that acrylic-polyurethanefilm had better heat resistance. The DTG curve of acrylic-polyurethane film possessed doublepeak which further confirmed the existence of core-shell structure. At the same time, the effectsof amount of emulsifier, amount of DMPA and mass ratio of PU/PA on properties of compositeemulsion and film were reviewed. The results showed that2%of amount of emulsifier,6.5%ofamount of DMPA,1:1.5of mass ratio of PU/PA could get better performance of emulsion.2. Core-shell type acrylic-polyurethane emulsion adhesive for pigment printing of cottonfabric application testing. Technology process: preparation of printing color pasteâ†'printingâ†'dryingâ†'curing, Test results showed that35%of the adhesive dosage,160℃of bakingtemperature,printing fastness and hand feeling achieved the application requirements.3. Research on the prevention of screen clogging. Emulsion film forming process wastracked by atomic force microscope （AFM）. Observation of the particle morphology of film surface drawwed that the higher the temperature, the faster and more deeply particles closed andsqueezed to each other; Diffusion coefficients of molecular chains （Ds） evaluates that1.009×10^-17cm²/s of Ds under60℃and1.944×10^-17cm²/s of Ds under80℃. Indicate that thehigher the temperature, the faster of molecular chain diffusion rate. These results described thatfilm-forming temperature rising would speed up the film forming rate of emulsion. In addition,the determination of water loss rate of emulsion and observation of screen mesh after printingrevealed that polyurethane components introduced to pure polyacrylic emulsion significantlyslowed down the water loss rate during the drying process and screen clogging was alsoimproved.