New technology for solid-state polymerization of polymers: Polyethylene terephthalate - Solid-state polyaddition

This article introduces the new M&G technology for Solid state polyaddition (SSPA) of polyethylene terephthalate (PET). The new SSPA is characterized by the following: (1) If is based on a novel chemical process, SSPA. (2) It is suitable for high-performance polyesters. (3) It enables separate control of many different key properties of the polyester (molecular weight, rheology, crystallinity, etc.). This intrinsic flexibility has already been exploited to produce tailor-made polyesters suitable for most important applications in packaging and related fields. It is also a powerful tool for the upgrading of recycled PET. The SSPA reaction has a much faster kinetic than the standard solid-state upgrading process so that accordingly the intrinsic viscosity (I.V.) built up in the solid state is much faster than that of solid-state polycondensation. This raises the possibility of solid-state upgrading at lower temperatures, where standard solid-state polycondensation reactions are barely noticeable. The accelerating reactions used in this process could be utilized to de-bottleneck the existing production plants in order to attain greater productivity, more flexibility, lower costs and higher quality. (C) 1997 by John Wiley & Sons, Ltd.