Inline solid state polymerization of pet flakes for manufacturing plastic strap

摘要

The present invention describes a process of making strap using both post consumer and non-post consumer PET of wide distribution intrinsic viscosity (IV) through direct solid state polymerization in a flaked state to produce PET with increased, heterogenous IV suitable for high performance strap extrusion. The process increases the IV of post-consumer resins, consisting principally of polyethylene terephthalate (PET), by chopping the post-consumer plastic into flakes and chunks, rolling the flakes and chunks, preheating the flakes, and further heating the flakes and chunks in an atmosphere of hot nitrogen gas, thereby increasing the intrinsic viscosity. PET polymers having increased viscosities according to the present invention provide a polymer useful in manufacturing high performance strap.