| Polyurethane (PU) and microfiber (MF) composite can be prepared with sea-island fiber nonwovens by dipping solvent PU slurry, solidifying in "H2O-DMF" coagulation bath and finally splitting in toluene or sodium hydroxide solution. At present, as the best material alternative to natural leather, the microfiber synthetic leather produced by this composite material, has similar microstructure to natural leather, and has excellent mechanical properties and performance. However, the extensive use of dimethyl formamide (DMF) during the production of PU/MF composite material not only pollutes the environment, but also will remain in the finished product. In order to solve these key issues, in this paper, WPU/MF composite material is prepared by using waterborne polyurethane (WPU) as the dipping material, the preparation techniques of WPU/MF composite is studied in detail, and the structure and properties of WPU/MF composite material are discussed. The following are the main research contents and results.This thesis has analysed the changes in the structure and properties of PU/MF composite processing, discussed the correlation between structure and properties of PU/MF composite, with PU/MF composite as the object of the research. The experimental results show that PU/MF composite consists of MF with three dimensional interwoven and PU filler having a microporous structure, The space between MF and PU, the microporous size of the PU filling body and the dispersion degree of MF are the primary factors of effect on the hydroscopicity, air permeability, water vapor permeability, softness and mechanical properties of PU/MF composite.This thesis has studied the preparation techniques, microstructure and performance of WPU/MF composite which is prepared with sea-island fiber nonwovens, by dipping WPU slurry, drying directly and splitting process. As the experimental results suggest that the structure of WPU/MF composite material made by polyvinyl alcohol (PVA) pre-treatment process has a better dispersion degrees, and it is conducive to improve the combination properties of the composite. In addition, the amount of WPU has a great influence on the properties of the composite. The WPU/MF composite has better hygienic properties compared with PU/MF composite.In this paper, the sea-island fiber nonwovens is used as the base material, dipped in WPU foaming slurry, and then directly dried to obtain the WPU/island fiber composite material, and finally the WPU/MF composite material is obtained through the splitting process. The preparation process, microstructure and properties of WPU/MF composite are studied. The experimental results show that the foaming ratio of the dipping slurry has a great influence on the microstructure, hygienic and mechanical properties of WPU/MF composite. When the foaming ratio is 180%, the comprehensive performance of WPU/MF composite is better. Compared with the non foaming WPU slurry impregnation process, the WPU/MF composites have better health performance and hand feeling, but their mechanical properties are relatively poor.In this paper, the sea-island fiber nonwovens is used as the base material, dipped in WPU foaming slurry, then solidified in the polymetallicacetate (SLA) solution to get the WPU/island fiber composite material, and finally the WPU/MF composite material is obtained through the splitting process. The preparation process, microstructure and properties of WPU/MF composite are studied. As the experimental results suggest that wet solidification process is beneficial to improve the mechanical properties of WPU/MF composite. The WPU/MF composite material prepared by dipping the foaming slurry with a foaming ratio of 180% into sea-island fiber nonwovens treated with PVA, solidifing in the 1.5% SLA solution, and splitting process, not only has a good feel, but also has good mechanical properties and health performance.In summary, the findings of the study provide a new idea and technology for the preparation of WPU/MF composite material, and provide the theoretical basis and support for the preparation of WPU microfiber synthetic leather. The application of this technology can solve the problem of DMF pollution and residue in the production of PU/MF composites. |
PDF Full Text Request