| This paper reviewed the preparation methods of waterborne polyurethane and the main materials of waterborne polyurethane at home and abroad. The development of PU leather in Chinese mainland was summarized briefly. The current situation, characteristics and advantages and disadvantages of PU leather industry was dissertated. Suggestions on further development were put forward. Aqueous polyurethane emulsions were synthesized from a polyether polyyol, toluene diisocyanate, dimethylol propionic acid, which were modified with diethylenetriamine (DTA) by inner crosslinking. The results showed that the modified emulsions were steady more than five months, the low quality of film coating was got in room temperature, but the excellent quality was got by heat treatment, water absorption of the film was decreased, the mechanical properties were improved. In this paper, the pollution of organic solvents to environment in leather finishing processes were discussed, and the methods and possibilities of reducing the pollution of solvents were introduced, for example, the selection of finishing agents and auxiliaries and application of coating machines and coating methods. Aqueous polyurethane emulsion was prepared with polyoxytetramethylene glycol (PTMG), isophone diisocyanate (IPDI), dimethylol propionic acid (DMPA) and ethylene diamine (EDA) as primary materials. A series of anionic aqueous polyurethanes were prepared mainly from diisonynate, polyether polyol and dimethylol propionic acid used as hydrophilic monomer. They were used in fabric treatment agent, paper lighting agent and adhesive for shoemaking and got excellent performances. For different applications the paper discussed the preparation and application process of the aqueous polyurethanes, The different fabric treatment agents can be obtained by using the polyether polyol with different molecular weights; the excellent paper lighting agent can be obtained by using the polyether polyol with different molecular weights; the excellent paper lighting agent can be prepared by adjusting the value of NCO/OH during reaction process; the aqueous shoemaking adhesive can be made from MDI and the peel strength up to 100N·cm-1.From the structure of polyurethane, the preparation process, physical properties of aqueous polyurethane emulsions and derived films, along with some technologies to improve its properties were reviewed. The aqueous polyurethane emulsions were prepared by internal emulsifier. The kinds of emulsifier and the emulsification mechanism were discussed. The characteristics of properties of hydroxy—crosslinking acrylate emulsion copolymer was made by way of centrifugal stability, elecctrolyte—resistence stability, water—resistence stability, IR and DSC. The results showed that the water—resistence stability of latex film and the crosslinking degree of copolymer can be obviously upgraded through core—shell technology distributing the living monomer onto the surface of the emulsion particle. The researchers first prepared superior aqueous polyurethane emulsion with core—shell construction as seed emulsion which further reacted with acrylate and silicone, obtained polymerized emulsion with no soap, it was applied to coat the fabric for experiment and properties of the coated fabric were fairly nice.Finally the paper described the development route, applied method and synthetic technique of cationic polyurethane leather coating agent in home and abroad. Crosslinking cationic polyurethane emulsions were synthesized from poly(propane oxide) glyol (N210, N330), TDI, N—methyl diethanol amine (MDEA) by acetone solution process, The effect of N330/N210 molar ratio on emulsion particle size, viscosity and the structure properties of PU films was studied. A water—based cationic polyurethane emulsion was prepared. This emulsion was mainly composed of polyester glycol, trimethylol propane, toluene dissocyanate (TDI) and N—methyl—diethaneolamine. The influences of the reaction temperature, content of each agent and stirring speed on the mechanical properties of the water—based polyurethane were investigated, giving its optimum composition. The polyurethane emulsion with good performance was prepared. And mechanical properties of the product are very good.
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