Polyester polymer particles having a small surface to center viscosity gradient

The present invention relates to polyester polymer particle having an intrinsic viscosity (It.V.), a surface, and a center, wherein the It.V. at the surface of the particle is less than 0.25 dL/g higher than the It. V. at the center of the particle. The polyester polymer particle is desirably crysta...

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Bibliographische Detailangaben
Hauptverfasser:	Colhoun Frederick Leslie, Ekart Michael Paul, Jernigan Mary Therese, Weinhold Stephen
Format:	Patent
Sprache:	eng ; slv
Schlagworte:	ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING CHEMISTRY COMPOSITIONS BASED THEREON CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS,e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES,DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS CONVEYING GENERAL PROCESSES OF COMPOUNDING HANDLING THIN OR FILAMENTARY MATERIAL MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS MAKING GRANULES OR PREFORMS METALLURGY ORGANIC MACROMOLECULAR COMPOUNDS PACKAGES PACKAGING ELEMENTS PACKING PERFORMING OPERATIONS PREPARATION OR PRETREATMENT OF THE MATERIAL TO BESHAPED RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIALCONTAINING PLASTICS SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR SHAPING OR JOINING OF PLASTICS STORING THEIR PREPARATION OR CHEMICAL WORKING-UP TRANSPORTING WORKING OF PLASTICS WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL WORKING-UP
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Beschreibung
Zusammenfassung:	The present invention relates to polyester polymer particle having an intrinsic viscosity (It.V.), a surface, and a center, wherein the It.V. at the surface of the particle is less than 0.25 dL/g higher than the It. V. at the center of the particle. The polyester polymer particle is desirably crystalline to prevent the particles from sticking to each other while drying, and desirably contains less than 10 ppm acetaldehyde. A polyester container, preferably a preform or beverage bottle, is made by feeding crystallized polyester particles having an It.V. of at least 0.70 dL/g to an extrusion zone, melting the particles in the extrusion zone to form a molten polyester polymer composition, and forming a sheet or a molded part from extruded molten polyester polymer, wherein at least a portion of the polyester particles have an It.V. at their surface which does not vary from their It.V. at their center by more than 0.25 dL/g, and the particles have not been solid state polymerized. Such polyester compositions have an It.V. suitable for containers, yet lose less It.V. during melt processing than existing polyesters.