Understanding Spunbond Extrusion & Thermal Calendering Technology

In-Line Spunbond Extrusion Technology

The manufacturing of Spunbond non-woven fabric takes place on high-precision continuous extrusion lines. Virgin polypropylene polymer granules are converted into finished rolls through an integrated sequence of thermal, aerodynamic, and mechanical operations.

Step 1: Polymer Melting & Precision Dosing Polypropylene homopolymer pellets are dried and pneumatically fed into temperature-zoned extruders (200°C–230°C). Precision gear pumps deliver the molten polymer at constant pressure to multi-orifice spinneret die packs.

Step 2: Filament Spinning & Quenching Molten polymer streams emerge through thousands of capillary holes. High-velocity conditioned cooling air rapidly quenches the filaments while aerodynamic drawing forces attenuate and stretch the fibers, locking in molecular orientation and high tensile strength.

Step 3: Aerodynamic Web Formation The continuous filaments are guided through high-speed aspirators and deposited onto a moving permeable vacuum conveyor wire. Negative air pressure underneath holds the fibers in place, forming an intertwined isotropic web.

Step 4: Thermal Point Calender Bonding The unbonded web travels between heated steel calender rollers under controlled hydraulic pressure. One roller features an engraved relief pattern (typically diamond or sesame) that fuses the filaments at discrete contact points without melting the full web area, retaining textile softness and drape.