Methods of post-polymerization injection in continuous polyethylene terephthalate production
AssigneeWellman, Inc.
InventorsCarl Steven Nichols, Tony Clifford Moore
Life of this patent
Estimating the term…
Abstract
The invention is a novel method for the late introduction of additives into a continuous process for making polyethylene terephthalate. The method employs a reactive carrier that functions as a delivery vehicle for one or more additives. The reactive carrier reacts with the polyethylene terephthalate, thereby binding the reactive carrier in the polyethylene terephthalate resin and preventing the emergence of the reactive carrier and additives from the polyethylene terephthalate during subsequent thermal processing.
Claims63
A method for introducing additives into a continuous process for making polyethylene terephthalate, comprising:
- reacting a terephthalate component and a diol component to form polyethylene terephthalate precursors;
- polymerizing the polyethylene terephthalate precursors via melt phase polycondensation to form polymers of polyethylene terephthalate;
- and
- thereafter introducing into the polyethylene terephthalate polymers a reactive carrier having a molecular weight of less than about 10,000 g/mol, the reactive carrier being the delivery vehicle for one or more additives.
A method for introducing additives into a continuous process for making polyethylene terephthalate, comprising:
- reacting a terephthalate component and a diol component to form polyethylene terephthalate precursors;
- polymerizing the polyethylene terephthalate precursors via melt phase polycondensation to form polymers of polyethylene terephthalate while continuously removing ethylene glycol;
- and
- thereafter introducing into the polyethylene terephthalate polymers a reactive carrier having a molecular weight of less than about 10,000 g/mol, the reactive carrier being the delivery vehicle for an additive;
- forming the polyethylene terephthalate polymers into chips or pellets prior to the solid state polymerization step;
- solid state polymerizing the polyethylene terephthalate polymers and the reactive carrier so that the reactive carrier becomes non-extractable during subsequent processing operations;
- and
- forming the polyethylene terephthalate polymers into containers.
A method for introducing additives into a continuous process for making polyethylene terephthalate, comprising:
- reacting terephthalic acid and ethylene glycol in a heated esterification reaction to form monomers and oligomers of terephthalic acid and ethylene glycol;
- polymerizing the monomers and oligomers via melt phase polycondensation to form polymers of polyethylene terephthalate;
- thereafter introducing an additive into the polyethylene terephthalate polymers using a reactive carrier, the reactive cater being a polyol having a molecular weight that permits the polyol to be pumped at near ambient temperatures and that is introduced to the polyethylene terephthalate polymers in quantities such that its concentration in the polymers is less than about one weight percent;
- forming the polyethylene terephthalate polymers into chips prior to the solid state polymerization step;
- and
- solid state polymerizing the polyethylene terephthalate polymers and the reactive carrier.
A method for introducing additives into a continuous process for making polyethylene terephthalate, comprising:
- reacting a terephthalate component and a diol component to form polyethylene terephthalate precursors;
- polymerizing the polyethylene terephthalate precursors via melt phase polycondensation to form polyethylene terephthalate polymers having a target intrinsic viscosity of at least about 0.45 dl/g;
- then, after the polyethylene terephthalate polymers have achieved the target intrinsic viscosity, introducing into the polyethylene terephthalate polymers a reactive carrier having a molecular weight of less than about 10,000 g/mol, the reactive carrier being the delivery vehicle for one or more additives;
- and
- thereafter completing the melt phase polycondensation of the polyethylene terephthalate polymers.
Dependencies are inferred from the claim text.