The Preparation Of Core-shell Fluorinated Acrvlic-polyurethane Adhesive And Its Application In Pigment Printing

The acrylic emulsion binder had good film forming, better adhesion and chemical stability, its threadlike structures would bring weakness of heat-adhesive and cold brittleness and clogging screen. Waterborne polyurethane has many advantages, for example, it had good low temperature flexible and high temperature-resistant, in the meantime The fluoropolymer had the property of ultra-low surface energy, excellent weatherability and heat resistance. This paper designed the modification of PA with polyurethane and fluorinated acrylate and made it into core-shell structure, not only could contain the advantages of both of them, but also inproved the disadvantage of clogging screen of pure acrylic emulsion.In this paper, core-shell type fluorinated acrylic-polyurethane emulsion adhesive was prepared after synthesis of double-bond terminated waterborne polyurethane seeded emulsion. In addition, the relation between film formation rate,dehydration rate of adhesive and clogging screen was explored. The research includes:1.The synthesis of double-bond terminated Waterborne polyurethane seeded emulsion. Fluorinated acrylates were added into, core-shell type fluorinated acrylic-polyurethane emulsion was prepared using seed emulsion polymerization. The molecular structure and core-shell structure were confirmed respectively by FT-IR and TEM; The TGA analysis proved that fluorinated acrylic-polyurethane film had better heat resistance. The DTG curve of fluorinated acrylic-polyurethane film possessed double peak which further confirmed the existence of core-shell structure. At the same time, the effects of reaction temperature, reaction time, amount of initiator, amount of emulsifier, amount of G04wereanalyseded. The results showed that reaction temperature was85℃, reaction time was100min,0.7%of amount initiator,2%of amount of emulsifier,6.0%of amount of DMPA,20%of amount of G04could get better performance of emulsion.2. Core-shell type fluorinated acrylic-polyurethane emulsion adhesive for pigment printing of cotton fabric application testing. The results showed:160℃of baking temperature,25%of the adhesive dosage, printing fastness and hand feeling achieved the application requirements. 3. Research on the prevention of screen clogging. The forming process of emulsion film was tracked 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 and squeezed to each other. The diffusion coefficients of molecular chains (Ds) evaluates that:1.524×10-17cm2/s (40℃),7.632×10-17cm2/s (80℃) and2.454×10-16cm2/s (120℃) Indicated that the higher the temperature, the faster of molecular chain diffusion rate. These results also could be described that film-forming temperature rising would speed up the emulsion’s film forming rate. In addition, the determination of water loss rate of emulsion and observation of screen mesh after printing revealed that polyurethane components and fluorinated acrylic introduced to pure polyacrylic emulsion could slowed down the water loss rate during the drying process and screen clogging was also improved.