How polyester fiber is made

Polyester fiber is the same plastic as a soda bottle, melted and pushed through a plate full of tiny holes.

stations: 6
things upstream: 18
raw sources: 8
steps from the ground: 6

The short version

Polyester fiber is made from PET. Dried PET chips are melted and pumped through a plate full of tiny holes, called a spinneret. The strands cool in air, are stretched to align their molecules, and are either wound as continuous filament or crimped and cut into short lengths for spinning like cotton.

Dry the PET chips

Chips of PET are dried in a hot airstream, because even a trace of water would break the chains when the plastic melts. Dry chips are fed straight to the spinning machine.

Goes in
PET plastic
Melt them in an extruder

A screw pushes the chips through a heated barrel where they melt into a clear, thick liquid. A pump meters the melt precisely into each spinning position.
Press it through the spinneret

The molten polymer is forced through a metal plate drilled with many fine holes. Each hole makes one filament, and cool air blown across them freezes the strands.
Stretch the filaments

The strands are drawn to several times their spun length, which lines up the molecules and makes the fiber strong and less stretchy.
Crimp, cut or wind

Continuous filament is wound onto bobbins for weaving. For staple fiber, the tow is crimped into waves and cut into short lengths that can be spun like cotton or wool.
Spin it into yarn

Staple fibers are blended, often with cotton, and twisted into yarn. It resists water, wind and weather better than plant-derived fibers do.

End of the linePolyester Next it goes into tire, soccer ball, marker pen and 30 more.

Worth repeating

Polyester is increasingly made from recycled PET, especially post-consumer plastic bottles.
Sold as Dacron, it also makes sailboat sails, and it is blended with natural fibers to give cloth that combines the properties of both.