The Production Process Of Polyester Fabric

Polyester fiber is produced using purified terephthalic acid (PTA)-or dimethyl terephthalate (DMT)-and ethylene glycol (EG) as primary raw materials. Through esterification (or transesterification) and polycondensation reactions, a melt or chips of polyethylene terephthalate (PET) are formed; these are subsequently processed via melt spinning and post-treatment to yield the final fibers. The basic process for melt spinning is as follows:

Drying Pre-treatment: Polyester chips undergo an initial pre-crystallization treatment at temperatures of approximately 160–180°C, followed by vacuum drying (at approximately 175°C) to reduce their moisture content to below 20 ppm. This step serves to prevent hydrolytic degradation during the subsequent high-temperature melting process.

Melt Extrusion: The dried polyester chips are melted under heated conditions, quantitatively conveyed by a metering pump to the spinning assembly, and extruded through a spinneret to form fine molten streams.

Cooling and Solidification: The molten streams rapidly cool and solidify in the air, forming nascent fibers.

Drawing and Orientation: The nascent fibers undergo drawing and orientation at temperatures above their glass transition temperature but below their melting point. This process aligns the molecular chains in an orderly fashion along the fiber axis, thereby enhancing both crystallinity and mechanical properties.

Post-treatment: Depending on specific product requirements, the fibers undergo further processing steps such as heat setting, winding onto bobbins (for filament fibers), or cutting into staple fibers.