Polyester resins with a special co-catalyst for high melt poly and SSP reactivity with enhanced color values
AssigneeFutura Polyesters Limited
InventorsSanjay Tammaji Kulkarni, Balasundaram Dilly Raj
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Abstract
The present invention relates to a PET resin and a process for producing polyethylene terephthalate (PET) resin having conventional catalysts such as antimony, titanium, tin or germanium compounds and a glycol insoluble tungsten compound or tungsten trioxide or tungsten carbide as co-catalyst. The tungsten compound as a co catalyst increases the rates of solid state polymerization and improves the ‘L’ color value.
Claims18
A polyethylene terephthalate (PET) resin having therein a glycol insoluble tungsten compound additive cocatalyst selected from the group consisting of tungsten trioxide, a mixture of tungsten trioxide and tungsten carbide and tungsten carbide during the making of the resin having a particle size ranging between 1 to 5 microns, and in quantities ranging from 5.0 to 30 ppm, based on mass of resin in Ethylene Glycol.
A process for the preparation of a resin comprising the steps of:
- a. preparing a paste comprising a:
- (i) diacid component selected from a group consisting of Terephthalic Acid (TPA) and
- (ii) diol component is selected from a group consisting of mono ethylene glycol (MEG);
- (iii) an antimony compound selected from a group consisting of antimony trioxide or antimony triacetate as a catalyst;
- and
- (iv) a cobalt compound acting as toner;
- b. esterifing the paste of step (a)
- c. optionally prepolymerizing the product of the above reaction in a prepolymerization reactor;
- d. polymerizing esterified material from step (b) or the prepolymer of step (c) in the presence of antimony compound as catalyst, at a reduced pressure and heat stabilizing using phosphorous compounds to obtain pellets or amorphous polymer melt which may subsequently cast as chips;
- and
- e. solid state polymerizing the pellets or amorphous polymer chips to get desired IV of 0.72 to 1.20 in the polyester resin, wherein
- f. at least one glycol insoluble tungsten compound selected from a group consisting of tungsten trioxide, tungsten carbide and a mixture of tungsten trioxide and tungsten carbide with a particle size of 1 to 5 microns dispersed in ethylene glycol, is added 5.0 to 30 ppm to at least at one of the steps a, b, c and d.
Dependencies are inferred from the claim text.