What is the calendering process of filter bag?

The finishing process of needle punched nonwoven filter materials for SFFILTECH bag filter mainly includes singeing, calendaring, dipping, heat setting, film covering, etc.

Calendering and singeing often occur in pairs on a singeing calendering machine. Calendering is to make the surface of needle punched nonwoven filter material smooth and flat. During calendering, the fiber molecular structure of the filter material surface wriggles and changes under the dual effect of the temperature and pressure of the hot press roller, and the fiber on the filter material surface shrinks, thus making the filter material surface smooth.

The thickness and permeability of needle punched filter material can also be adjusted by calendering. Due to the compaction of the press roller, the thickness and permeability of the filter material will decrease. The setting temperature of the calender roller is between the glass transition temperature and the softening point temperature of the fiber. According to this feature, a layer of low melting point fiber can be added on the surface of the filter material to form a bright filter material under the effect of calendering.

SFFILTECH filter bag factory forms a standardized operation process according to different filter material fiber materials and molding requirements to achieve “material based calendering”, so as to ensure product quality and provide customers with high-quality filter material products.