High‐strength uniaxially drawn tapes from scrap recycled poly(ethylene terephthalate)

We made an effort to develop a manufacturing process for high‐strength packaging straps from recycled poly(ethylene terephthalate) (PET) beverage bottles. High‐strength tapes from low‐viscosity bottle‐grade PET cannot be obtained by single drawing to a natural draw ratio because the strength of such tapes is below expectation. To increase that strength, we developed a double‐drawing process, consisting of a second drawing step after free drawing with the natural draw ratio. The second stretching of tapes proceeded without necking and uniformly over the entire tape length. The extrusion/stretching was performed on the laboratory line, consisting of a single screw extruder, a chill roll, two sets of slow and fast rolls separated by a heating tunnel, and wind‐up roll. The tape drawn to a total draw ratio of 6 had a tensile strength slightly below 700 MPa and an initial slope of ≈ 15 GPa. Strain‐induced crystallization was the origin of strong texture after single drawing, whereas plastic deformation mechanisms of crystals were activated in the second step of drawing: the (100)[001] chain and (100)[010] transverse slips led to clear further refining of (1¯05) X‐ray pole figure. Industrial scale up of the double drawing delivered tapes with strength slightly below 700 MPa. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1426–1435, 2002