Sinco Engineering S.p.A. (Localita Ribrocca S.N., I-15057 Tortona / AL) has developed new technology for the production of high molecular weight polyester resins from low molecular weight resins. Its solid state polyaddition process (SSPA) will, according to the company, enable the production of improved grades of PET and PET alloys that will open up new applications, as well as enhancing the performance of traditional products such as bottles. The new process can also be used to process recycled PET.

The SSPA process consists of rapidly extruding the PET with polyaddition additives (CS1). After pelletising the chips are fed into the SSP unit where, because of the additive, very high intrinsic viscosity can be reached with relatively low residence time. Not only will this open up applications which require higher viscosities such as extrusion foaming, but for applications which do not need particularly high viscosity, such as preforms, it will either dramatically speed up production at the same temperatures, or give the possibility of running production at much lower temperatures. Bottle grade PET produced using this technology also displayed improved mechanical properties and 20% better barrier properties.

Sinco Engineering is a division of M&G Group (Viale Milanofiori, Palazzo A/6, I-22090 Assago) which is involved in both PET technology and the manufacture of PET preforms. The company claims that 36% of world capacity for bottle grade PET uses M&G-Sinco technology and the development of this new SSPA process will allow for debottlenecking at existing production plants. In Italy the group has a capacity of 150,000 t/y of which 35,000 t/y goes for captive use. This is expected to be expanded to 200,000 t/y from 1997 with in house use of 100,000 t/y.

READER SERVICE: Speech "New technology for solid state upgrading of PET" by Dr. Ing. G. Ghisolfi and Dr. Prof. Hussein Al Ghatta presented at Interplas ‘96 (English): PIE-No. 40139.