Processing Characteristics of Recycled Poly(Ethylene Terephthalate) as Melt Spun Fibers

Recycled poly (ethylene terephthalate) (r-pet) used in blends with a fiber grade material (f-pet) is investigated. As-spun fibers of r-pet, f-pet, and r/f-pet blends are made at winding speeds ranging from 1000 to 4000 m/min (mpm), with subsequent drawing in the range of 1.6 to 4.0×. Spinning and drawing behaviors of the fibers are analyzed using orientation (birefringence), boil-off shrinkage, calorimetric (dsc), and mechanical measurements. The fully oriented yarns from the r-pet show a tensile strength of 70% of the fiber grade, with 3.2 g/d (r-pet) to 4.6 g/d (f-pet), which still meets and surpasses minimum industrial requirements. The dsc study of these materials indicates that the decreased crystallinity of the r-pet may be the main cause for the decreased tensile strength of the product.