History

• Malden Mills in Massachusetts developed polyester fleece in the 1980s, using its expertise in making fake fur fabric. Its Polarfleece is soft, warm, durable and quick-drying, according to Polartec.com.
  
  

Making PET

• Virgin polyester is the result when the manufacturer heats a mix of terephthalic acid and ethylene glycol. The result is dihydroxydiethyl terephthalate, which the manufacturer then heats under pressure to make PET. The factory extrudes and dries the cooled liquid and crushes it into chips. Used PET bottles can also be a source material. To recycle these bottles, the fleece manufacturer sorts, washes, dries them and crushes them into chips.
  
  

Spinning

• The factory heats the chips into liquid form and forces them through spinnerets to form fibers, which are wound onto a spool, according to MadeHow. The fibers are then drawn out to several times their length to help strengthen and set them. They are then crimped, dried, cut, baled, aligned into thick strands, coiled, spun into yarn, and spooled.
  
  

Dyeing

• The factory dyes the yarn, then dries, knits, naps it to a fuzzy texture and shears it. The fleece maker then sprays the resulting fabric to set its texture or to waterproof it before a clothing manufacturer cuts it and makes it into a garment.