US2009131627A1PendingUtilityA1

Polyester polymer particles having a small surface to center molecular weight gradient

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Assignee: EASTMAN CHEM COPriority: Mar 8, 2004Filed: Oct 24, 2008Published: May 21, 2009
Est. expiryMar 8, 2024(expired)· nominal 20-yr term from priority
Inventors:Frederick Leslie ColhounMichael Paul EkartMary Therese JerniganStephen Weinhold
C08G 63/183C08G 63/185Y10T428/1352B29C 48/832B29C 48/793Y10T428/2982C08G 63/181B29B 9/12B29K 2067/00C08G 63/189C08J 3/12
64
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Claims

Abstract

There is now provided a polyester polymer particle having an 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.

Claims

exact text as granted — not AI-modified
1 . A polyester polymer particle comprising a polyester polymer comprising:
 (a) a carboxylic acid component comprising at least 90 mole % of the residues of terephthalic acid, derivates of terephthalic acid, naphthalene-2,6-dicarboxylic acid, derivatives of naphthalene-2,6-dicarboxylic acid, or mixtures thereof, and   (b) a hydroxyl component comprising at least 90 mole % of the residues of ethylene glycol,   based on 100 mole percent of the carboxylic acid component residues and 100 mole percent hydroxyl component residues in the polyester polymer,
 wherein said polyester particle has an It.V. of at least 0.70 dL/g, 
 the absolute value of the difference in the ItV. between the center and the surface of the polyester particles fed to the extrusion zone is less than 0.25 dL/g, and 
 the Polyester Particles have an acetaldehyde level of 10 ppm or less. 
   
     
     
         2 . The polyester particle of  claim 1 , wherein the polyester particle has an It.V. of at least 0.74 dL/g. 
     
     
         3 . The polyester particle of  claim 2 , wherein the polyester particle has an It.V. of at least 0.77 dL/g. 
     
     
         4 . The polyester particle of  claim 1 , wherein the absolute difference is less than 0.2 dL/g. 
     
     
         5 . The polyester particle of  claim 1 , wherein the absolute difference is less than 0.15 dL/g. 
     
     
         6 . The polyester particle of  claim 1 , wherein the polyester particle has a degree of crystallinity of at least 25%. 
     
     
         7 . The polyester particle of  claim 1 , wherein the polyester particle contains less than 10 ppm acetaldehyde. 
     
     
         8 . The polyester particle of  claim 1 , wherein said polyester particle has a number average weight of at least 1.0 g per 100 of the polyester particles. 
     
     
         9 . The polyester particle of  claim 1 , wherein said polyester particle comprise virgin polyester polymer. 
     
     
         10 . The polyester particle of  claim 1 , wherein the polyester polymer contains at least:
 (a) a carboxylic acid component comprising at least 92 mole % of the residues of terephthalic acid, or derivates of terephthalic acid, or mixtures thereof, and   (b) a hydroxyl component comprising at least 92 mole % of the residues of ethylene glycol,   based on 100 mole percent of the polycarboxylic acid component residues and 100 mole percent hydroxyl component residues in the polyester polymer.   
     
     
         11 . The polyester particle of  claim 1 , wherein the absolute difference is not more than 0.10 dL/g. 
     
     
         12 . The Polyester particle of  claim 11 , wherein the absolute difference is not more than 0.20 dL/g. 
     
     
         13 . The polyester particle of  claim 11 , wherein the polyester polymer contains at least:
 (a) a carboxylic acid component comprising at least 96 mole % of the residues of terephthalic acid, or derivates of terephthalic acid, or mixtures thereof, and   (b) a hydroxyl component comprising at least 96 mole % of the residues of ethylene glycol,   based on 100 mole percent of the carboxylic acid component residues and 100 mole percent hydroxyl component residues in the polyester polymer.   
     
     
         14 . The polyester particle of  claim 13 , wherein the polyester particle has a degree of crystallinity of at least 25%. 
     
     
         15 . The Polyester particle of  claim 1 , wherein a bulk of said polyester particles has a volume of at least 1 cubic meter. 
     
     
         16 . The polyester particle of  claim 15 , wherein the absolute difference is not greater than 0.20 dL/g. 
     
     
         17 . The polyester particle of  claim 16 , wherein the absolute difference is not greater than 0.10 dL/g. 
     
     
         18 - 19 . (canceled) 
     
     
         20 . A polyester particle having a degree of crystallinity of at least 25% and an It.V. of at least 0.70 dL/g, said polyester particle having an It.V. at its surface and an It.V. at its center, wherein the absolute value of the difference in the It.V. between the center and the surface of the polyester particles fed to the extrusion zone is less than 0.25 dL/g; and wherein the polyester particles have an acetaldehyde level of 10 ppm or less. 
     
     
         21 . The polyester particle of  claim 20 , wherein the polyester polymer contains:
 (a) a carboxylic acid component comprising at least 90 mole % of the residues of terephthalic acid, or derivates of terephthalic acid, or mixtures thereof, and   (b) a hydroxyl component comprising at least 90 mole % of the residues of ethylene glycol,   based on 100 mole percent of the carboxylic acid residues and 100 mole percent hydroxyl residues in the polyester polymer.   
     
     
         22 . The polyester particle of  claim 21 , wherein the degree of crystallinity is at least 35%, and the It.V. of the polyester particle is at least 0.74 dL/g. 
     
     
         23 . The polyester particle of  claim 21 , wherein the absolute difference is 0.15 dL/g or less. 
     
     
         24 . The polyester particle of  claim 23 , wherein the absolute difference is 0.05 dL/g or less. 
     
     
         25 . (canceled) 
     
     
         26 . Polyester particles having a particle weight of greater than 1.0 g per 100 of the polyester particles and less than 100 g per 100 of the polyester particles, said polyester particles, comprising at least 75% virgin polyester polymer, comprising:
 (a) a carboxylic acid component comprising at least 90 mole % of the residues of terephthalic acid, or derivates of terephthalic acid, or mixtures thereof, and   (b) a hydroxyl component comprising at least 90 mole % of the residues of ethylene glycol,   
       based on 100 mole percent of the carboxylic acid component residues and 100 mole percent hydroxyl component residues in the polyester polymer,
 the polyester particles having
 a degree of crystallinity of at least 25%, 
 an It.V. of at least 0.77 dL/g, 
 an absolute value of the difference in the It.V. between the center and the surface of the polyester particles fed to the extrusion zone of no greater than 0.15 dL/g, and 
 an acetaldehyde level of 10 ppm or less. 
 
 
     
     
         27 . The polyester particles of  claim 26 , wherein a bulk of the Polyester particles has a volume of at least 1.0 cubic meter. 
     
     
         28 . The Polyester particles of  claim 27 , wherein in the absolute difference is not greater than 0.15 dL/g. 
     
     
         29 . The polyester particles of  claim 28 , wherein the absolute difference is not greater than 0.10 dL/g. 
     
     
         30 . The polyester particles of  claim 29 , wherein the absolute difference is not greater than 0.05 dL/g. 
     
     
         31 - 33 . (canceled) 
     
     
         34 . The polyester particles of  claim 1 , wherein the polyester particles are obtained from underwater pelletizers. 
     
     
         35 . The polyester particles of  claim 1 , wherein said polyester particles fed to the extrusion zone comprise spherical particles. 
     
     
         36 . The polyester particles of  claim 1 , wherein the polyester particles contain phosphorus. 
     
     
         37 . The polyester particles of  claim 1 , wherein the polyester particles are obtained by polycondensing in the presence of a catalyst comprising titanium. 
     
     
         38 . The polyester particles of  claim 1 , wherein the polyester particles are obtained by polycondensing in the presence of a catalyst consisting essentially of titanium. 
     
     
         39 . The polyester particles of  claim 1 , wherein the polyester particles are obtained by polycondensing in the presence of a catalyst comprising antimony. 
     
     
         40 . The polyester particles of  claim 1 , wherein the polyester particles are obtained by polycondensing in the presence of a catalyst consisting essentially of antimony. 
     
     
         41 . The polyester particles of  claim 1 , wherein the polyester particles contain a reheat rate enhancing aid. 
     
     
         42 . The polyester particles of  claim 1 , wherein the reheat enhancing aid comprises elemental antimony, carbon black, graphite, or black iron oxide. 
     
     
         43 . The polyester particles of  claim 1 , wherein the polyester particles comprise strain crystallized polyester polymers. 
     
     
         44 . The polyester particles of  claim 1 , wherein the polyester particles are dried at a temperature of 140° C. or more prior to feeding the polyester particles into the extrusion zone. 
     
     
         45 . The polyester particles of  claim 44 , wherein the polyester particles are dried at a gas flow rate of 0.2 to 5 scfm per lb/hr of the polyester particles. 
     
     
         46 . The polyester particles of  claim 1 , wherein the polyester particles contain a metal deactivator. 
     
     
         47 . The polyester particles of  claim 1 , comprising melting the polyester particles to form a molten polyester polymer and injection molding the molten polyester polymer to form a container suitable for heat set beverage bottles. 
     
     
         48 . A polyester particles for making a container from a polyester(s) polymer, comprising
 feeding spherical polyester particles having a degree of crystallinity of at least 15% and an ItV. of at least 0.70 dL/g to an extrusion zone,   melting the spherical polyester 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 the absolute value of the difference in the ItV. between the center and the surface of the spherical polyester particles fed to the extrusion zone is less than 0.25 dL/g, and the spherical polyester particles are not solid state polymerized before introducing said spherical polyester particles into the extrusion zone, and the spherical polyester polymer particles comprise:   (a) a carboxylic acid component comprising at least 92 mole % of the residues of terephthalic acid, or derivates of terephthalic acid, or mixtures thereof, and   (b) a hydroxyl component comprising at least 92 mole % of the residues of ethylene glycol,   
       based on 100 mole percent of the carboxylic acid component residues and 100 mole percent hydroxyl component residues in the polyester. 
     
     
         49 . The polyester particles of  claim 48 , wherein the degree of crystallinity of the polyester particles is at least 40%. 
     
     
         50 . The polyester particles of  claim 48 , wherein the absolute value of the difference is less than 0.05 dL/g. 
     
     
         51 . The polyester particles of  claim 48 , wherein the particles are dried at a gas flow rate of 0.2 to 5 scfm per lb/hr of the polyester particles. 
     
     
         52 . The polyester particles of  claim 48 , wherein a metal deactivator is added to a melt phase for making the polyester particles. 
     
     
         53 . The polyester particles of  claim 48 , comprising injection molding the molten polyester polymer to form a container suitable for heat set beverage bottles. 
     
     
         54 . The polyester particles of  claim 48 , wherein the polyester particles are obtained from underwater pelletizers. 
     
     
         55 . The polyester particles of  claim 48 , wherein the polyester particles comprise strain crystallized polyester polymers. 
     
     
         56 . The polyester particles of  claim 48 , wherein the polyester particles have an acetaldehyde level of 2 ppm or less. 
     
     
         57 . The polyester particles of  claim 48 , wherein ItV. of the polyester particles fed to the extrusion zone is 0.80 dL/g or more.

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