Synthesis Of Polyurethane For PU Leather And Develop The Novel Polyol

Most of polyurethane leather is prepared from polyester or polyether. Polyester based polyurethane shows low hydrolysis resistance, and polyether based polyurethane exhibits remarkable hydrolysis resistance. However the films prepared from polyether show poor surface hardness and mechanical properties. Polyurethane derived from poly (propylene carbonate) diol (PPC) exhibits superior mechanical properties, friction resistance, and hydrolysis resistance due to multi-carbonate and ether linkages in the molecular chain. Polyurethane leather slurry from PPC as the waterborne polyurethane s (WPU) leather finishing agents was prepared to improve rigidity of water-based resin surface. Poly-cyclohexene carbonate diol(PCHC) was synthesized from carbon dioxide and cyclohexene, and the effects on polymerization rate were also investigated. The obtained results are listed as follows:1. PPC based polyurethane leather slurry with high molecules and viscosity was prepared by trifle NCO amount method under 80℃, and catalyst was added with the first addition stage of diphenyl methane diisocyanate.2. Alkali resistance of PPC based polyurethane leather slurry was superior with comparing polybutylene adipate (PBA) based leather slurry, and slightly inferior compared with polytetrahydrofuran (PTMG) type leather slurry.3. Compared with the PBA or PTMG waterborne leather finishing agents, the film fabricated form PPC showed poor glossiness.4. The enhanced properties (back-adhesive resistance, tensile strength, thermal resistance and solvent resistance) and reduced crystallinity of film were obtained by modifying with trimethylolpropane.5. PPC based leather finish agent was modified with y-aminopropyl triethoxysilane. The introducing of silane coupling agent improved the diameter and diameter distribution of the emulsion and surface hydrophobicity, however reduced the water absorption.6. Poly(cyclohexene carbonate) diol (PCHC) (Mn=3000) was prepared by copolymerization of cyclohexene oxide and carbon dioxide with DMC as catalyst. The structure of PCHC characterized by FI-IR,1H-NMR and 13C-NMR showed excellent alternating copolymerization structure. The glass transition temperature of PCHC was high(69.8℃), and the maximum thermal decomposition temperature was about 320℃.7. The effect of polymerization conditions on reaction rate was also investigated. Increasing the reaction temperature and addition of catalyst could improve the reaction rate. The reaction pressure had obvious effect on the induction period, but less effect on the rate of polymerization reaction.8. PCHC based waterborne polyurethane was prepared the first time. The results showed that the film was brittle, cracks appeared in the process of film forming. Furth research was not conducted due to time restricting.