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Aqueous polyurethane dispersion medium is water binary colloidal system, compared with solvent-based polyurethane with a non-toxic, non-flammable, do not pollute the environment, etc., in leather finishing, automotive painting, fiber processing, paper industry chemicals, coating and adhesives, and many other fields has been widely used. However, latent heat of evaporation of the water of the organic solvent than conventional high latent heat of evaporation, causing the ratio of solvent-based polyurethane aqueous polyurethane drying time is long, it is difficult to meet the fast-paced modern shoe production line of adhesive for shoes drying performance technical requirements. Solid content is increased to improve water-based polyurethane adhesive for shoes drying properties and other properties of the most effective ways. This research uses prepolymer dispersion to diisocyanate (HDI, IPDI) and a polyester diol (PBA1000, PBA2000, PBA3000, PCDL2000 and PEBA2000) as main raw materials, DMPA is a hydrophilic chain extender to obtain a polyurethane prepolymer; neutralized with triethylamine salt, the prepolymer forcibly dispersed in water and ethylene diamine chain extender, the finally obtained aqueous polyurethane emulsion. The research of the three types of formulations, and its performance testing and characterization. These three recipes are: IPDI / HDI, a single polyester waterborne polyurethane synthetic; IPDI, single waterborne polyurethane polyester synthesis; IPDI, mixed two-component waterborne polyurethane polyester synthesis. Various formulations were prepared had good performance waterborne polyurethane emulsion. The content on the above research study to get some conclusions: polymerization reaction time to four hours for the best; hydrophilic monomer amount of DMPA on the emulsion viscosity and particle size has a decisive influence, the dosage should ensure emulsion stability as little as possible under the premise, the content was found DMPA preferably 3-4%; HDI and IPDI is a molar ratio is important, HDI amount of not more than, or experiments are not successful, the appropriate value to 3:7; soft segment content of 65-70% for the best, the most suitable time for the aqueous polyurethane dispersion adhesive; compare five different aqueous polyurethane emulsion polyester synthesis, found PBA2000 better; through the use of a polyester synthesized by mixing solid content of 46 to 49% of the number of emulsion PBA2000 find the best mixing and PCDL2000. In addition, the R value (NCO to OH molar ratio), also do the research, and the emulsion by GPC and SEM, TEM characterizations. GPC test results show that the obtained number average molecular weight WPU emulsion were above 104, the weight average molecular weight of more than 110,000 maximum; TEM observation of the obtained results show that the molecular WPU emulsion of a certain size distribution.
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