Optimizing the porosity of flame-retardant nonwoven fabrics requires systematic control from three dimensions: fiber characteristics, web-forming process, and consolidation method. Fiber fineness and length are fundamental factors affecting porosity. Finer fibers form a denser network structure, reducing the average pore size; while longer fibers increase pore connectivity through entanglement. By adjusting the fiber crimp and cross-sectional shape (e.g., hollow or irregular cross-sections), the spatial arrangement of fibers during stacking can be altered, thereby precisely controlling the porosity distribution. Mixing fibers with different properties (e.g., coarse-fine blends or long-short fiber composites) can achieve a tiered pore distribution, meeting the requirements of specific applications for air permeability and filtration accuracy.

The flame-retardant mechanism of flame-retardant nonwoven fabrics for electrical applications is mainly based on the synergistic effect of chemical and physical flame retardancy. Chemical flame retardancy is achieved by adding flame retardants to polyester fibers. Common flame retardants include phosphorus-based, nitrogen-based, and halogen-based compounds.

The performance changes of electrical nonwoven fabrics under high-temperature environments are mainly reflected in their mechanical properties, insulation properties, and dimensional stability. As temperature increases, the molecular chain mobility of polyester fibers increases, potentially leading to material softening or deformation. At high temperatures, the tensile strength and tear strength of nonwoven fabrics typically decrease, especially near the glass transition temperature of polyester, where this change is more pronounced. Therefore, in high-temperature applications, it is necessary to select polyester varieties with better heat resistance or add heat-resistant additives.

Customizing the color of nonwoven fabrics can be achieved through several methods, mainly including fiber dyeing, masterbatch addition, coating coloring, and printing processes. Fiber dyeing involves dissolving polyester or other raw materials before spinning and adding dye, using solution dyeing to give the fiber its own color. This method produces uniform and long-lasting colors with high color fastness, suitable for mass production. However, dyed fibers have lower flexibility; changing colors requires re-preparing the spinning solution, making it suitable for production needs with fixed color codes.