Abstract: A process for increasing the rate of polymerization of low molecular weight polyester particles under solid state processing conditions whereby the progress of polymerization is preferred over the progress of crystallization for a given mass of particles.

Abstract: A melt spinning apparatus for spinning continuous polymeric filaments including a first stage gas inlet chamber adapted to be located below a spinneret and optionally a second stage gas inlet chamber located below the first stage gas inlet chamber. The gas inlet chambers supply gas to the filaments to control the temperature of the filaments. The melt spinning apparatus also includes a tube located below the second stage gas inlet chamber for surrounding the filaments as they cool. The tube may include an interior wall having a converging section, optionally followed by a diverging section.

Abstract: A process for producing a polyester that comprises 65 to 90 wt. % poly(alkylene ether) glycol. The process comprises the step of copolymerizing a preformed polyester polymer having an inherent viscosity of at least 0.4 dL/g and a poly(alkylene ether) glycol, to obtain said polyester comprising said 65 to 90 wt. % poly(alkylene ether glycol).

Abstract: Polyester yarns whose polyester fibers are of simple oval peripheral cross-section of aspect ratio at least about 1.85:1 have shown better dye yield in fabrics than polyester staple fibers having lower aspect ratios. Such superior cross-sections for polyester staple fibers have also provided advantages in open-end spinning in providing yarns with fewer spinning failures than fibers of conventional round cross-section.

Abstract: A method for recovering and recycling excess hydrogen from process vent streams in the production of highly pure terephthalic acid where the production of the pure terephthalic acid comprises catalytically hydrogenating impure terephthalic acid, which typically contains 4-carboxybenzaldehyde (4-CBA), color bodies and other impurities, in aqueous liquid phase solution at elevated temperature and pressure.

Abstract: A process for increasing the pill resistance of a polyester polymer wherein the polyester polymer is produced by polymerizing a polymerization mixture comprising (a) a carbonyl compound or an oligomer of the carbonyl compound and (b) a glycol. The process comprises contacting the polymerization mixture with a cross-linker comprising (RO)mSi(X)nZp, wherein: R is hydrogen, a hydrocarbon, or a hydrocarbon oxygen; X is a hydrocarbon or a hydrocarbon oxygen; Z is a hydrophilic group; m is 1 to 3; n is 1 to 3; and p is 1 to 30.

Abstract: A sulfonated copolyester of the reaction product of: (a) one or more aromatic dicarboxylic acids or an ester thereof; (b) one or more aliphatic dicarboxylic acids or an ester thereof; (c) one or more sulfonated compound; and (d) isosorbide. The polyesters are useful to form articles of increased biodegradability.

Abstract: An aromatic carboxylic acid such as terephthalic acid is produced by the liquid phase oxidation of a precursor thereof, the oxidation being carried out in such a way that substantially all of the aromatic carboxylic acid produced in the course of the reaction is maintained in solution during the reaction.

Abstract: Cobalt and/or manganese is recovered from the ash obtained following incineration of the catalyst containing residue arising from the liquid phase oxidation of an aromatic carboxylic acid such as terephthalic acid. Recovery is effected by contacting the ash with an organic acid or an organic acid anhydride such as acetic anhydride, optionally in the presence of bromide ions (e.g. HBr), so that the cobalt and/or manganese metals are recovered as monocarboxylic acid soluble salts thereof thus permitting recycle thereof to the liquid phase oxidation process.

Abstract: An acidic organics-containing waste water stream (12) derived from for example plant for the production of an aromatic carboxylic acid such as terephthalic acid is treated to allow recovery of alkali and water for recycle to the production process. The treatment comprises adjusting the pH of the waste water stream using an alakaline medium, oxidising (10) the organics content of the stream to convert the same to water, carbon dioxide and (bi)carbonate ions, and supplying the treated stream to a reverse osmosis membrane (28, 30) to produce a retentate containing (bi)carbonate ions and cations derived from the alkaline medium and a permeate which is substantially free of those components. The retentate (46) is recycled for use in adjustment of the pH of the waste water stream and, if desired, water-consuming facilities which can tolerate less pure water.

Abstract: An improved process for producing highly pure aromatic carboxylic acid from an impure solid acid product whereby the solid acid product is efficiently dissolved in a suitable solvent at relatively low temperatures despite the presence of solid lumps.

Abstract: A method for recovering methyl acetate and residual acetic acid in a two-stage process for producing pure terephthalic acid having a first oxidation stage and a second purification stage.

Abstract: Process for producing pure terephthalic acid having improved means for recovering and/or recycling terephthalic acid precursors, residual acetic acid and other reaction by-products, such as methyl acetate.

Abstract: A process for producing pure carboxylic acids by catalytic liquid phase oxidation of a suitable precursor in a solvent in which the oxidation reaction is carried out in a plug flow reaction zone at a high solvent:precursor ratio and reaction conditions sufficient to maintain the pure acid in solution as it is formed, and product produced from such process.

Abstract: An improved process for preparing an aromatic dicarboxylic acid wherein the improvement resides in dehydrating and recovering solvent from a feed stream having from 20% to 40% by weight water via azeotropic distillation with organic phase reflux using an entrainer selected from isobutyl acetate, n-propyl acetate or an entrainer with a boiling point between isobutyl acetate and n-propyl acetate.

Abstract: Process for removing organic constituents from a high pressure exhaust gas stream in a bromine assisted air oxidation process in which the exhaust gas contains methyl bromide.

Abstract: Dicarboxylic acids or esters thereof are recovered from solid phase polyester materials, such as post-consumer products and factory scrap, by subjecting the polyester to at least two hydrolysis stages in at least the first of which the amount of water used is substantially less than needed to effect total conversion of the polyester to the dicarboxylic acid. Also the diol content is controlled in the course of carrying out the hydrolysis. The hydrolysis reactions may be preceded by reaction of the polyester with a diol, the resulting depolymerisation products then being hydrolysed.

Abstract: In plant for the production and processing of an aromatic carboxylic acid such as terephthalic acid, at least some of the plant components (especially those exposed to an acidic reaction medium at elevated temperatures and pressures in excess of 180.degree. C. and 8 bara respectively) are fabricated from duplex stainless steels and the conditions under which such plant components are exposed to the reaction medium are controlled to maintain a low corrosion rate.

Abstract: Purified terephthalic acid is prepared by a process of subjecting an aqueous solution of crude terephthalic acid to hydrogenation to reduce impurities, crystallizing this solution to produce a slurry of purified terephthalic acid in an aqueous liquor, and carrying out an integrated separation washing process.

Abstract: A polyester resin composition made of a polyester resin containing a polyalkylene oxide soft segment component, a plasticizer, a crystallization promoter, and a brominated flame retardant is developed, said composition having good flame resistance and mechanical properties.