Solid state polymerisation of PET

• Main Authors: ADAMS, KARL G, VAN ERDEN, DONALD, ENRIQUEZ, MANUEL C, NELSON, JAMES P, VADNAIS, GARY L
• Format: Patent
• Language: English; French; German
• Published: 18.06.2003
• Edition: 7
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; GENERAL PROCESSES OF COMPOUNDING; MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; WORKING-UP

The present invention is 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 non-peletized state to produce PET with an 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 preferably chopping the post-consumer plastic into flakes and chunks, rolling the flakes and chunks, preheating the flakes, and further heating the pre-heated flakes and chunks in an atmosphere of hot nitrogen gas, thereby increasing their intrinsic viscosity. PET polymers having increased viscosities provide a polymer useful in manufacturing a high performance strap material.