Patent ID: 7199210
Filing Date: 2007-04-03
Classification: C08G,C08K

Abstract:
1. A process for the preparation of polyethylene terephthalate (PET), said process comprising the steps of; (a) preparing a slurry of pure terepthalic acid, mono ethylene glycol, isopthalic acid in the presence of reduced amount of a cobalt compound and colour toners, (b) pre-dispersing an optimal quantity of a potassium titanium oxide oxalate-containing catalyst in a polymer matrix to obtain a master batch adding the dispersed titanium complex in the polymer matrix from the master batch to said slurry, at a desired temperature and at selected stages of the process, (c) esterifying said slurry in a reduced time period and under controlled degree of polymerisation to obtain a pre-polymer, and retaining a portion of said pre-polymer as pre-polymer heel for subsequent batch reactions, (d) polymerising the pre-polymer in a reduced time period and enhanced degree of polymerisation to obtain a polymer melt, (e) stabilizing said final polymer melt by adding at least a heat stabilizing additive, and (f) extruding and converting the final polymer melt to form amorphous pellets under nitrogen pressure and solid-state polymerizing said pellets to obtain polyethylene terepthalate, said polymer free from yellow colour.