Melt Spinning of Polyester
category
Polyester fibres are produced by melt spinning: PET chips (IV 0.60–0.68 dL/g) are dried to <50 ppm moisture, melted in an extruder at 280–295°C, metered through a gear pump, filtered through a sand/screen pack, and extruded through spinnerets (50–200 holes, 0.2–0.4 mm diameter). Filaments are quenched, finished with spin finish, and wound or collected as tow.
Role
Melt spinning is the fundamental production process for all polyester filament and staple fibre. Understanding its parameters, rheology, and engineering design is essential for controlling fibre structure and properties.
Subtopics
- Pre-Spinning Drying and Moisture Control PET must be dried to <50 ppm moisture (preferably <30 ppm) before melt spinning to prevent hydrolyti…
- Extruder Design and Melt Rheology Single-screw extruders (L/D ratio 24:1 to 30:1) melt PET chips through compression, melting, and met…
- Spinneret Design and Pack Assembly Spinnerets are precision-drilled plates (stainless steel or titanium) with 0.15–0.40 mm diameter hol…
- Quenching and Filament Solidification Extruded filaments are quenched by cross-flow (or radial-flow for POY) air at 20–25°C, 0.4–0.6 m/s v…
- Spin Finish Composition and Application Spin finish is applied at 0.3–0.8% owf via metered kiss-roll or oiling jet. Composition: 60–80% lubr…
- Winding Speed and Spin-Draw Processes Winding speed determines fibre structure: low-speed (500–1000 m/min): undrawn yarn (UDY), amorphous,…
- Staple Fibre Production and Tow Processing Staple fibre production: multifilament tow (100,000–500,000 dtex) from multiple spinning positions i…
- Bicomponent and Microfibre Spinning Bicomponent fibres use dual-channel spinneret blocks to co-extrude two polymer streams: side-by-side…
- POY, FDY, HOY and Draw-Texturing Feed Yarns Partially oriented yarn (POY, 3000–3500 m/min, birefringence 0.055–0.075) is the primary feed for dr…
- High-Tenacity and Industrial Yarn Spinning High-tenacity polyester yarn (HT, >7 cN/dtex) for tyre cord, geotextiles, and seatbelts requires hig…