Abstract: The friability of crystallized PTT and solid stated PTT can be effectively reduced by lowering the temperature of the quenching water used in the pelletizing of the melt polycondensation polymer to between 32° F. (0° C.) and 65° F. (18° C.). In addition, the robustness of solid stated PTT pellets is effectively increased by using a prepolymer with a lower intrinsic viscosity (IV) or by increasing the IV of the solid stated product.

Abstract: The friability of crystallized PTT and solid stated PTT can be effectively reduced by lowering the temperature of the quenching water used in the pelletizing of the melt polycondensation polymer to between 32° F. (0° C.) and 65° F. (18° C.). In addition, the robustness of solid stated PTT pellets is effectively increased by using a prepolymer with a lower intrinsic viscosity (IV) or by increasing the IV of the solid stated product.

Abstract: The pelletized product of melt condensation polymerization of 1,3-propanediol and terephthalic acid is crystallized in a vessel designed for continuous fluidized bed flow of the pellets in water at a temperature within the range of about 65 to about 100° C. Hot-water treatment in the vessel permits crystallization of the pellets in a continuous operation and results in an increase of the crystallinity of the polymer to greater than about 35% and an increase in pellet density.

Abstract: The present invention is a process for producing poly(trimethylene terephthalate) (PTT) at an increased solid state polymerization rate, wherein 1,3-propane diol and an aromatic acid or a dialkyl ester thereof are esterified or transesterified, the esterification or transesterification product is polycondensed, and the polycondensation product is pelletized and then subjected to continuous solid state polymerization at a temperature of 200 to 225° C., preferably 210 to 225° C. In one embodiment of the present invention, the temperature range is 200 to 220° C., and the pellet size of the polymer to be solid state polymerized is from 1.0 to 1.5 g/100. In another embodiment of the present invention, the solid state polymerization is carried out at 210 to 225° C. for from 1 to 20 hours and then the temperature is increased to above the initial melting point of the polymer to produce a PTT polymer with an intrinsic viscosity of 1.3 dl/g or greater.

Abstract: The present invention is an improvement upon the process for producing poly(trimethylene terephthalate) (PTT) wherein 1,3-propanediol (PDO), and optionally other diols, and an aromatic diacid or diester thereof, and optionally other diacids or diesters, are esterified or transesterified and the esterification or transesterification product is polycondensed to produce a prepolymer which is solid state polymerized to produce a polymer with a desired intrinsic viscosity (IV). The prior art process includes the SSP prereaction steps of crystallization, drying/annealing, and preheating. The improvement in the present invention comprises crystallizing and preheating the PTT polymer in one step, without a drying/annealing step in between. Thus, the prepolymer still has a substantial moisture content when it is first exposed to the SSP reaction temperature inside the crystallizer/preheater.

Abstract: The present invention is an improvement upon the process for producing poly(trimethylene terephthalate) (PTT) wherein 1,3-propanediol (PDO), and optionally other diols, and an aromatic diacid or diester thereof, and optionally other diacids or diesters, are esterified or transesterified and the esterification or transesterification product is polycondensed to produce a prepolymer which is solid state polymerized to produce a polymer with a desired intrinsic viscosity (IV). The prior art process includes the SSP prereaction steps of crystallization, drying/annealing, and preheating. The improvement in the present invention comprises crystallizing and preheating the PTT polymer in one step, without a drying/annealing step in between. Thus, the prepolymer still has a substantial moisture content when it is first exposed to the SSP reaction temperature inside the crystallizer/preheater.

Abstract: The present invention is a process for producing poly(trimethylene terephthalate) (PTT) at an increased solid state polymerization rate, wherein 1,3-propane diol and an aromatic acid or a dialkyl ester thereof are esterified or transesterified, the esterification or transesterification product is polycondensed, and the polycondensation product is pelletized and then subjected to continuous solid state polymerization at a temperature of 200 to 225° C., preferably 210 to 225° C. In one embodiment of the present invention, the temperature range is 200 to 220° C., and the pellet size of the polymer to be solid state polymerized is from 1.0 to 1.5 g/100. In another embodiment of the present invention, the solid state polymerization is carried out at 210 to 225° C. for from 1 to 20 hours and then the temperature is increased to above the initial melting point of the polymer to produce a PTT polymer with an intrinsic viscosity of 1.3 dl/g or greater.

Abstract: The pelletized product of melt condensation polymerization of 1,3-propanediol and terephthalic acid (or alkyl ester thereof) is crystallized by immersion in water at a temperature within the range of 60 to about 100° C. Hot-water treatment increases the crystallinity of the polymer to at least about 35% and increases pellet density to about 1.33 g/cm3.

Abstract: A process for crystallizing a polyethylene naphthalate copolymer by:a) copolymerizing at least 60 mole % of 2,6-naphthalene dicarboxylic acid, based on the total moles of carboxylic acids, with polyols such as at least 80 mole % of ethylene glycol and from 2 mole % to 20 mole % of a polyol having three or more carbon atoms, each based on the total moles of polyols, to form PEN copolymer solids, andb) subsequently crystallizing the PEN copolymer solids by heating the solids to at least their sticking temperature at an average rate of at least 10.degree. C./min, to form agglomerate-free crystallized solids.The process may be performed under agitation. The pellets heated up in a during the crystallization step do not agglomerate or suddenly expand as the temperature rises to and through the sticking temperature of the PEN copolymers. The process allows one to rapidly heat up PEN during crystallization, and do so without conducting a prior drying step or a devolitilization step.

Abstract: A process is disclosed to prepare a polyester resin having a predetermined acetaldehyde (AA) content whereby the IV of the melt phase resin is constrained to a certain range resulting in a longer SSP time to achieve a higher level of IV for the resin with an AA content of 1 PPM or less. The resultant resin can be transformed into a bottle preform, which, when blown, forms a bottle suitable for packaging of mineral water.

Abstract: A process is disclosed for the crystallization of a PEN prepolymer containing volatile components. The temperature is maintained at a temperature in the range of about 20.degree. C. above the Tg and about 10.degree. C. below the Tm while the PEN prepolymer is agitated. The PEN prepolymer is present as chips or pellets. The pressure during crystallization is maintained at a level higher than the vapor pressure of the volatile components in the PEN prepolymer chips or pellets.

Abstract: A process is disclosed for the crystallization of a PEN prepolymer containing volatile components. The temperature is maintained in the range of about 20.degree. C. above the Tg and about 10.degree. C. below the Tm while the PEN prepolymer is agitated. The PEN prepolymer is present as chips or pellets. The crystallization is performed in the presence of a liquid or a mixture of liquids that do not degrade the polymer during crystallization. The liquid or liquids employed may be those whose vapor pressure at the amorphous PEN softening temperature are insufficient to forestall expansion of the pellets. When this class of liquid or liquids is employed, the crystallization vessel is pressurized with an inert gas, including air, to prevent the prepolymer expansion. If the liquid or liquids possess sufficiently high vapor pressures at the PEN softening temperature, the pellets do not expand even without the inert air pressurization.

Abstract: This invention includes a process for preparing a solid state polymerized poly(ethylene naphthalate) or PEN polymer comprising: (1) preparing a molten PEN polymer with an intrinsic viscosity of from about 0.25 dl/g to about 0.55 dl/g, (2) dispersing an inert gas into the molten PEN polymer to form a foamed PEN polymer with a void fraction of from about 0.10 to about 0.50, (3) forming the foamed PEN polymer into granules, (4) devolatilizing the granular PEN polymer at a temperature of from about 80.degree. C. to about 140.degree. C., (5) crystallizing the devolatilized PEN polymer at a temperature of from about 150.degree. C. to about 260.degree. C., and (6) solid state polymerizing the crystallized PEN polymer at a temperature of from about 235.degree. C. to about 265.degree. C. to form a solid state polymerized PEN product.

Abstract: This invention includes a process for preparing a solid state polymerized poly(ethylene naphthalate)or PEN polymer comprising: (1) preparing a molten PEN polymer with an intrinsic viscosity of from about 0.25 dl/g to about 0.55 dl/g, (2) dispersing an inert gas into the molten PEN polymer to form a foamed PEN polymer with a void fraction of from about 0.10 to about 0.50, (3) forming the foamed PEN polymer into granules, (4) devolatilizing the granular PEN polymer at a temperature of from about 80.degree. C. to about 140.degree. C., (5) crystallizing the devolatilized PEN polymer at a temperature of from about 150.degree. C. to about 260.degree. C., and (6) solid state polymerizing the crystallized PEN polymer at a temperature of from about 235.degree. C. to about 265.degree. C. to form a solid state polymerized PEN product.

Abstract: Polyester prepolymer granules with open-ended cavities provide greatly improved solid state polymerization rates by improving reaction by-product diffusion characteristics.

Abstract: This invention is a process for solid state polymerization of polyester using multiple reactors in series to achieve molecular weight increases, as measured by intrinsic viscosity, in excess of 0.25 dl/g with low levels of undesirable by-products.

Abstract: Polyester prepolymer granules with open-ended cavities provide greatly improved solid state polymerization rates by improving reaction by-product diffusion characteristics.

Abstract: High molecular weight polyester resins are sometimes produced from low molecular weight polyester prepolymers having the same composition by solid state polymerization. Polyester prepolymers are generally converted from the amorphous state to the crystalline state prior to solid state polymerization in order to raise their sticking temperature. This is done to keep the polyester prepolymer from sticking together as a solid mass in the solid state polymerization reactor. Such polyester prepolymers are traditionally crystallized by simply heating them to an elevated temperature at which crystallization occurs. However, polyethylene naphthalate prepolymer cannot be crystallized by utilizing this simply traditional approach. This inventions discloses a process for crystallizing amorphous polyethylene naphthalate prepolymer which comprises: (1) heating the amorphous polyethylene naphthalate prepolymer to a temperature which is within the range of about 80.degree. C. to about 140.degree. C.

Abstract: A process for the continuous production of high molecular weight polyethylene terephthalate wherein the crystallized prepolymer having an intrinsic viscosity of at least 0.3 is dried, preheated and polymerized in a single moving bed reaction zone. The method is characterized by an inert gas atmosphere and a reaction zone with a temperature gradiant ranging from about 170.degree. C. at the uppermost portion and a higher temperature of about 225.degree. C. at the lowermost portion.

Abstract: A high molecular weight polyester is produced by a two stage process: a partial melt process until the intrinsic viscosity of the polyester prepolymer reaches from about 0.35 to about 0.62 dl/g, and a solid state polymerization in a static bed until the intrinsic viscosity of the polycondensed polymer reaches at least 0.70 dl/g. The melt process employs greater concentrations of initial acid in combination with a heel or the addition of make-up acid to achieve optimal carboxyl content for the polyester prepolymer capable of use in the static bed solid state polymerization. This prepolymer with an optimal carboxyl content achieves a maximum solid state polymerization rate in a static bed. The production of the high molecular weight polyester by the two stage process minimizes chemical instability and deleterious polymerization byproducts.