What factors affect the voltage withstand performance of insulating nonwoven fabrics?

2025-12-03 14:23:11

The voltage withstand performance of insulating nonwoven fabrics mainly depends on the dielectric properties and structural design of the material itself. The purity of the fiber raw material is a fundamental factor; impurities or defects can become conductive channels, significantly reducing the material's voltage withstand capability. Polyester fibers, due to their stable molecular structure and high crystallinity, typically exhibit excellent dielectric strength; however, the presence of conductive components such as metal particles or carbon black in the fibers can have a negative impact. The uniformity of fiber diameter and length also directly affects the uniformity of the electric field distribution; uneven fiber arrangement may lead to localized electric field concentration, forming weak points for breakdown.

Material thickness is a key parameter affecting voltage withstand performance. Thicker nonwoven fabrics can withstand higher voltages, but increased thickness must be matched with fiber density to avoid a decrease in actual insulation effect due to excessive porosity. Simultaneously, thickness uniformity is equally important; excessively thin areas can become potential sources of early breakdown. Precise control of thickness during the manufacturing process is a crucial step in ensuring stable voltage withstand performance.

Environmental conditions also have a significant impact on voltage withstand performance. Increased humidity causes water molecules to adsorb onto the material surface, forming a conductive film and reducing surface resistivity. Increased temperature can intensify molecular chain movement, increasing dielectric loss. Furthermore, long-term exposure to polluted environments, such as the deposition of oil or chemicals, can alter the material's insulation properties. Therefore, insulating nonwoven fabrics for specific environmental applications often require hydrophobic or antifouling treatments.

The bonding state between fibers is another important factor. Welded joints formed by thermal bonding and adhesive joints formed by chemical bonding have different dielectric properties. The former may experience localized changes in crystallinity due to high-temperature processing, while the latter is affected by the insulating properties of the adhesive itself. Although needle punching provides high mechanical strength, the physical entanglement between fibers can create microscopic defects. Optimizing the bonding process requires striking a balance between mechanical and electrical properties.