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Polyethylene terephthalate and its production method

A technology of polyethylene terephthalate and polyethylene terephthalate, which is applied in the field of polyethylene terephthalate and its manufacturing, can solve the problem of increasing the cleaning frequency and replacement frequency of molds and nozzles , lower commodity value, lower productivity, etc., to achieve the effect of not easy to have bad appearance, good hue, good (b value)

Active Publication Date: 2015-07-29
MITSUI CHEM INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] It is known that the cyclic trimer precipitates on the surface of films, sheets, bottles, etc. when molding polyester, causing roughness and whitening of the surface, resulting in a decrease in commercial value.
In addition, when the film is used for packaging of sterilized (retort) food, due to high temperature and high pressure treatment, the surface of the film will be whitened, and printing on the film will also become difficult, reducing the commercial value.
[0006] Furthermore, it is also known that there is a problem that the ring terpolymer contaminates the inner walls of molds and nozzles during the polyester molding process and processing process, which increases the frequency of cleaning and replacement of the molds and nozzles used.
However, in such a solid-state polycondensation method, there is a problem that a long time is required for the treatment and the productivity is lowered.
In Patent Document 3, the heat treatment method of polyester under a specific inert gas flow rate is described, but it does not satisfy the hue

Method used

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  • Polyethylene terephthalate and its production method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0131] Add 13,000 parts of high-purity terephthalic acid, 5,000 parts of monoethylene glycol, and 6.88 parts of a 20% aqueous solution of tetraethylammonium hydroxide into the autoclave. With a pressure of 0.17MPaG, it takes 4 hours to raise the temperature from 100°C to 260°C for further reaction It took 1.5 hours. The water generated by this reaction was distilled out of the system from time to time. Next, 2.1 parts of germanium dioxide and 2.2 parts of trimethyl phosphate (hereinafter referred to as TMP) were added as a polycondensation catalyst. The temperature was raised to 280° C. over 1 hour, the pressure in the system was reduced to 0.27 kPa abs, the reaction was continued for 43 minutes, and ethylene glycol was distilled out of the system. After the reaction is terminated, the reactant is cut into a chip shape. The intrinsic viscosity (IV) of polyethylene terephthalate obtained by the above liquid phase polycondensation L ) is 0.54dl / g. In addition, the terminal C...

Embodiment 2

[0138] Except having changed the solid-phase polymerization conditions as follows, it carried out similarly to Example 1, and produced polyethylene terephthalate. Solid-phase polymerization conditions were such that solid-state polycondensation was performed at 220° C. for 7 hours in a batch-type solid-phase polycondensation apparatus in a nitrogen stream containing 0.38% by weight of monoethylene glycol. The intrinsic viscosity (IV) of polyethylene terephthalate after solid-state polycondensation S ) is 0.62dl / g, and the IV increase range ΔIV (IV from liquid phase polycondensation to solid phase polycondensation S -IV L ) is 0.08dl / g. In addition, the cyclic trimer (CT) content was 0.34% by weight.

[0139] This polyethylene terephthalate was hot-water-treated by the same method as Example 1.

[0140] The polyethylene terephthalate obtained in this way has an intrinsic viscosity of 0.62 dl / g, a CT content of 0.34% by weight, a Ge content of 66 ppm, Si and Al of 1 ppm or l...

Embodiment 3

[0147] Using a continuous polycondensation device in which the first, second, third, and fourth reactors are tank-type and the fifth reactor is a twin-screw rotary horizontal reactor, continuous polymerization is performed as follows to produce polyethylene terephthalate. In advance, in the reactor in which 33500 parts by weight of the reaction solution (at the time of steady operation) was retained, 6458 parts by weight / hour of The slurry prepared by mixing high-purity terephthalic acid and 2615 parts by weight / hour of ethylene glycol was subjected to esterification reaction. In this esterification reaction, the mixed solution of water and ethylene glycol was distilled off.

[0148]The esterification reaction product (lower condensate) was controlled so that the average residence time would be 3.5 hours, and was continuously introduced with stirring into the second reactor maintained at 260° C. and normal pressure. In this reactor 2, the ethylene glycol solution of germaniu...

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Abstract

PURPOSE: A polyethylene terephthalate is provided to have low inherent viscosity, to reduce the content of a cyclic trimer, and to have excellent color (b value). CONSTITUTION: A polyethylene terephthalate contains 30-70 ppm of a germanium metal. The inherent viscosity of the polyethylene terephthalate is 0.62-0.67 dl / g, the cyclic trimer content is 0.34 wt% or less, the nitrogen content is 2 ppm or less, each of the Si and Al contents is 1 ppm or less, and the color (b value) is 1 or less. A manufacturing method of the polyethylene terephthalate includes a liquid phase polycondensation process which manufactures a polymer by liquid phase polymerizing a terephthalic acid-containing aromatic dicarbonic acid or the ester-forming derivative thereof and an ethylene glycol-containing aliphatic diol or the ester-forming derivative thereof under the presence of a germanium compound as a polymerization catalyst; and a solid phase polycondensation process which changes the inherent viscosity of the polymer and the cyclic trimer.

Description

technical field [0001] The present invention relates to polyethylene terephthalate which is particularly preferably used for molded articles such as films, and more specifically relates to a polyethylene terephthalate which has an intrinsic viscosity suitable for film production and is less likely to cause appearance defects derived from cyclic trimers, and Polyethylene terephthalate with good color phase (b value) and its production method. Background technique [0002] Conventionally, polyester resins such as polyethylene terephthalate resins are excellent in mechanical strength, chemical stability, gas barrier properties, fragrance retention, hygienic properties, etc., and are relatively inexpensive, so they are widely used as films, fibers, bottle etc. [0003] Furthermore, since polyester films are recently used for optical applications such as displays, it is urgent to reduce the amount of foreign matter in polyester films. [0004] Such a polyester contains a few pe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G63/183C08G63/86C08G63/78C08G63/80
CPCC08G63/183C08G63/78C08G63/80C08G2261/63C08J5/00
Inventor 铃木智博西本吉孝小浦隆
Owner MITSUI CHEM INC
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