关键词: 超细纤维, 聚酰胺涂层, 湿法涂层, 工艺优化

Abstract: To improve the wearing performance of traditional polyamide wet coating fabrics and solve various problems such as poor wear resistance and powder shedding of conventional polyamide coatings filled with inorganic powder particles such as kaolin, calcium carbonate, and wollastonite, it is necessary to find a new filler component and develop a new process flow for preparing polyamide wet coating fabrics based on this. The short fibers of polyamide/polyethylene (PA/PE) ultrafine fibers after fiber opening treatment were blended with methanol/calcium chloride/polyamide polymer solution to prepare microfiber composite polyamide coating slurry. Wet coating processes such as double-sided scraping, water bath exchange, and drying were carried out on polyester/spandex blended base fabrics by using microfiber composite polyamide coating slurry to obtain a polyamide wet coating fabric filled with microfibers. Then, various testing methods were used to evaluate its wearability and other properties. The results indicate that with the increase of the amount of microfibers added, the viscosity of the coating slurry gradually increases from 246.7 mPa·s to 250.8 mPa·s. With the extension of storage time, the viscosity of the coating slurry increases from 245 mPa·s to 290 mPa·s. As the viscosity of the coating slurry increases, the coating thickness shows a significant upward trend, increasing from 20 μm to 40 μm. As the duration of phase transformation increases, the pore structure on the surface of the coating gradually becomes significant and dense, the stiffness of the fabric increases, and the phenomenon of powder shedding intensifies. The stiffness and coating thickness of the polyamide coated fabric filled with microfibers show an increasing trend with the increase of phase transition time, and the curve gradually becomes smooth. As the phase transition time increases, the dry and wet friction properties of the microfiber filling polyamide coated fabric show a phenomenon of first increase and then decrease. After the baking temperature is increased to 120 ℃, the surface and internal structure of the coating are damaged, and cracks appear on the surface. The hardness of the coating increases, but there is no significant change in the coating thickness. As the baking temperature increases, the dry and wet friction properties of the polyamide coated fabric filled with microfibers show a decreasing trend. The presence of microfibers can significantly improve the friction resistance of coatings and greatly improve the problem of powder shedding. With the increase of the amount of microfibers added, the stiffness of the polyamide coated fabric filled with microfibers shows a gradual increasing trend within a small range. The coating thickness increases from 20 μm to 36 μm. After a thickness of 28 μm, there is a phenomenon of powder loss in the coating, which gradually intensifies. As the thickness of the coating increases, the dry and wet friction properties of the microfiber filled polyamide coated fabric show a downward trend, while the stiffness shows an upward trend. In conclusion, the viscosity of the coating slurry itself is positively correlated with the placement time and the amount of microfibers used. Comparative experimental analysis shows that the most suitable placement time is 1 h. The stability and strength of the coating structure are influenced by the phase transition time and baking temperature. Through gradient test analysis, the optimal phase transition time is 5 s, and the optimal baking temperature is 80 ℃. The addition of microfibers has an optimized effect on the powder shedding defect and dry wet friction performance of the coating. Through comparative experiments, it is found that the optimal amount of microfibers in the coating slurry is 7 g. The coating thickness has a significant impact on the friction resistance, stiffness, and other properties of microfiber filling polyamide coated fabrics, with an optimal range of 20 to 24 μm.

Key words: microfiber, polyamide coating, wet coating, process optimization