The Spunbond Extrusion & Converting Process

Virgin homopolymer polypropylene (PP) granules (MFI 25–40) are pneumatically conveyed, dried, and gravimetrically dosed with specialized masterbatches (UV stabilizers, color pigments, hydrophilic agents, or flame retardants). The polymer is thoroughly homogenized and melted across multi-zone temperature-regulated screw extruders at 200°C–230°C.

High-precision positive-displacement melt gear pumps meter the molten polymer under uniform pressure into spinneret packs containing thousands of micro-capillary orifices. The polymer is extruded into continuous, uniform filament strands with zero denier variance.

As filaments exit the spinneret plate, they pass through a laminar conditioned quench-air chimney. High-velocity pneumatic draft tubes stretch the strands at speeds exceeding 3,000 m/min, aligning polymer molecular chains along the axis for superior MD/CD tensile strength and elongation resistance.

Attenuated continuous filaments are discharged onto a high-speed moving vacuum wire conveyor belt. Downward suction pulls the randomized filaments into an interlocking, homogeneous fibrous mat with balanced multi-directional mechanical properties.

The unbonded web passes between heated steel calender rollers under precise hydraulic linear nip pressure (200°C–215°C). Engraved embossing patterns (Big Dot, Medium Dot, Small Dot, or Diamond) fuse the filaments at discrete points without chemical resins or adhesives.

Continuous non-contact optical laser scanners and beta-gauge sensors inspect the fabric for GSM uniformity, pinholes, and foreign inclusions. Heavy-duty circular rotary knives trim roll edges with ±1 mm precision, returning trimmings into closed-loop recycling.