Spheroidal polyester polymer particles

a polyester and polymer technology, applied in the field of polymer particles, can solve the problems of insufficient agglomeration and not usually agglomeration of pellets, and achieve the effect of preventing agglomeration and preventing agglomeration

Inactive Publication Date: 2006-03-02
EASTMAN CHEM CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As a result, conventional pellets do not usually agglomerate in the dryers which feed an injection molding machine or an extruder.
, the problem does not usually result in sufficient agglomeration to completely block a flow of pellets from the dryer.

Method used

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  • Spheroidal polyester polymer particles
  • Spheroidal polyester polymer particles
  • Spheroidal polyester polymer particles

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0139] The pellets were heated in a hopper of a dryer. The dryer consisted of a bank of five hoppers serviced by a single Conair drying unit by means of an insulated manifold system. Typically, the pellets to be investigated were placed in Hopper 1 (first hopper on the supply manifold), dummy pellets were placed in Hopper 3, and the air supply valves to Hoppers 2, 4, and 5 were closed. This procedure was followed to prevent excessively high air flow through Hopper 1.

[0140]FIG. 1 illustrates the geometry and dimensions in inches of the dryer hopper used in the experiments.

[0141] The base of the hopper is sealed by simple sliding gate valve. The slide may be completely removed to fully open the hopper exit. The dryer was thoroughly preheated to its operating temperature prior to charging the hopper with pellets. Hopper 3 was charged with about 20 pounds (roughly 80% of the hopper capacity) of dummy pellets (typically CB12) and a similar quantity of test pellets were loaded into Hopp...

example 2

[0150] In this series of experiments, the angle of repose PET pellets of various shapes and morphologies was analyzed. The angle of repose is a measure of the frictional properties of a granular material and may be related to the propensity of pellets to stick in a dryer. A higher angle of repose means that the pellets are more likely to stick in a dryer, whereas a lower angle of repose indicates a material is more free-flowing.

[0151]FIGS. 2 and 3 show fixtures for the testing of angle of repose of granular materials. The test fixtures were designed to function inside a large dryer at elevated temperatures. The dryer is equipped with a baffle to direct air flow through the test fixtures and heat the pellets effectively.

[0152] The gate test (FIG. 2) is a box comprising a wire mesh base 1, two fixed side walls 3, a fixed back wall 5, and a vertically removable side, or gate 7. The inside dimensions of the gate test box are 5.75×5.75×8.00 inches. At the start of the test, the gate 7 ...

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PUM

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Abstract

Spheroidal polyester polymer particles, as well as preforms and stretch blow molded bottles made from the spheroidal particles, are provided which have: A) an It.V. of at least 0.72 dL/g, and either B) at least two melting peaks (on a DSC first heating scan), wherein one of said at least two melting peaks is a low peak melting point having a peak temperature within a range of 140° C. to 220° C. and having a melting endotherm area of at least the absolute value of 1 J/g, or
    • C) a low degree of crystallinity within a range of at least 20% and a maximum degree of crystallinity Tcmax defined by the equation:
Tcmax=50%−CA−OH
where CA is the total mole % of all carboxylic acid residues other than terephthalic acid residues, based on 100 mole % of carboxylic acid residues in the polyester polymer, and OH is the total mole % of hydroxyl functional compound residues other than ethylene glycol residues, based on 100 mole % of the hydroxyl functional compounds residues; or both B) and C); and optionally but preferably D) 10 ppm or less of residual acetaldehyde.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 606,727 filed Sep. 2, 2004, and U.S. Provisional Application No. 60 / 618,951 filed Oct. 15, 2004, the entirety of which is hereby incorporated by reference.1. FIELD OF THE INVENTION [0002] The field of the invention pertains to polyester polymer particles having a particular morphology and geometry. 2. BACKGROUND OF THE INVENTION [0003] Conventional polyester polymer particles and pellets are typically cylindrically shaped, are solid state polymerized, and have high degrees of crystallinity. As a result, conventional pellets do not usually agglomerate in the dryers which feed an injection molding machine or an extruder. While some sticking occurs at drying temperatures (150° C. to 185° C.), the problem does not usually result in sufficient agglomeration to completely block a flow of pellets from the dryer. [0004] We have found it advantageous to provide a polyeste...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C08G63/02
CPCC08G63/88Y10T428/1334Y10T428/1355B29B9/12B29B7/007B29B7/726B29B2009/165B29B9/16C08G63/02C08G63/00C08J3/12
Inventor WEINHOLD, STEPHENCOLHOUN, FREDERICK LESLIEEKART, MICHAEL PAULGAMBLE, BENJAMIN BRADFORD
Owner EASTMAN CHEM CO
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