WO1994001484A1 - Procede de reduction de l'indice de jaune d'un granulat polyester postcondense - Google Patents

Procede de reduction de l'indice de jaune d'un granulat polyester postcondense Download PDF

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Publication number
WO1994001484A1
WO1994001484A1 PCT/CH1993/000157 CH9300157W WO9401484A1 WO 1994001484 A1 WO1994001484 A1 WO 1994001484A1 CH 9300157 W CH9300157 W CH 9300157W WO 9401484 A1 WO9401484 A1 WO 9401484A1
Authority
WO
WIPO (PCT)
Prior art keywords
crystallization
post
color
temperature
yellowness index
Prior art date
Application number
PCT/CH1993/000157
Other languages
German (de)
English (en)
Inventor
Werner Kaegi
Arthur Ruf
Edwin Boller
Original Assignee
Buehler Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Buehler Ag filed Critical Buehler Ag
Publication of WO1994001484A1 publication Critical patent/WO1994001484A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/78—Preparation processes
    • C08G63/80—Solid-state polycondensation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
    • C08G63/88—Post-polymerisation treatment

Definitions

  • the invention relates to a process for reducing the yellowness index of post-condensed polyester granules e.g. Copolyester or homo-PET for bottle granulate and other.
  • PET polyethylene terephthalate
  • copolyesters based thereon are increasingly being used for the production of bottles and containers, in particular for carbonated beverages.
  • the so-called bottle granulate must have a high molecular weight (intrmsic viscosity) and a high purity (lowest acetaldehyde content). These properties can only be achieved by thermal post-treatment of the polyester in the solid phase.
  • a third requirement concerns the appearance of such a bottle. It should be clear, transparent and colorless like pure glass and must not have any shades of yellow, e.g. through thermo-oxidative secondary reactions. can occur in the manufacturing process of the polyester.
  • the color of the bottle granulate thus represents a quality criterion for the granulate, and for the bottle manufacturer.
  • the requirements for film and foil granulate are also analogous.
  • the discoloration may be due to the thermal degradation product acetaldehyde (see E.P. Goodmgs (Thermal Degradation) of
  • catalysts are added homogeneously to the liquid reaction mass to accelerate the reaction in the polyester production. Certain catalysts are then deactivated again by further additives, and the polyester is stabilized against thermo-oxidative degradation.
  • a whole series of known additives of this type are described in German patent specification 27 15 932, for example manganese acetate and antimony trioxide as catalysts or phosphoric acid or triphenyl phosphate as inhibitors / stabilizers.
  • Polyester produced according to this recipe usually has a slightly yellowish-gray inherent color, which is not desired in the aforementioned articles. Neutralization is also possible through additive color mixing (complementary colors), for example through an additional additive with a blue tint effect.
  • cobalt compounds such as the preferred cobalt acetate.
  • Such a polyester formulation is disclosed in U.S. Patent 4,499,226 wrote.
  • Cobalt is also catalytically active (cf. US Patent 4,499,226 and German Patent 27 15 932), but is more expensive than
  • the invention is therefore based on the object of achieving a reduction in the yellowness index of post-condensed polyester granules by improving the solid-phase treatment while partially simplifying the described prior art.
  • the task according to the invention was surprisingly achieved by crystallizing the initially amorphous polyester material at a very low temperature of less than 145 ° C., preferably at 105 to 125 ° C.
  • the unexpected reduction in the yellowness index achieved thereby surprisingly remains during the subsequent solid-phase post-condensation carried out at a much higher temperature until the end product of this treatment.
  • the b * values from Tab. 1 refer to the international standard color measurement system CIE-L * , a * , b * .
  • the three values are
  • Granulate assessment zero is the neutral point, positive values correspond to a yellow tint and negative values correspond to a blue tint.
  • Solid phase treatment is followed by the solid phase polycondensation, which is usually carried out at temperatures of more than 200 ° C., with a residence time of several hours.
  • the color advantage (color value right into the blue area) was retained at the low crystallization temperatures according to the invention parallel to the other changes in the high-temperature treatment right down to the end product.
  • the first stage of the treatment is possible with air, which is easier and cheaper than inert gas.
  • Characteristic of the process according to the invention is the unusually low temperature of the first treatment stage (crystallization), ie a crystallization temperature of less than 145 ° C., preferably 105 to 125 ° C.
  • the treatment time must be selected to be sufficiently long to achieve an approximately constant final crystallization value (measured with density) corresponding to this temperature level (approx.
  • the surprisingly found advantage of the procedure according to the invention consists in a significantly better color (reduction in the yellowness index of the end product compared to the previously known process flow with higher crystallization temperatures).
  • the crystallization is followed by a solid phase post-condensation known per se and the final cooling of the polyester granulate.
  • the process can be carried out batchwise or continuously.
  • the only requirement placed on the gas composition is that no oxidative damage may occur.
  • oxygen-free inert gases as a rule nitrogen
  • vacuum in the case of a batch apparatus, also vacuum are used.
  • the crystallization can also be carried out with air without disadvantage for the granulate color.
  • the continuous system from Buhler has proven to be particularly well suited to the production-related implementation of the process, despite the known system
  • polyester should primarily be understood to mean polyethylene terephthalate (PET) and PET-based copolyesters. All diol and dicarboxylic acid compounds are suitable as CO components.
  • the diols these are primarily the main component, ethylene glycol, alkylene glycols such as diethylene glycol, 1,3-propylene glycol or 1,4-butylene glycol, and cycloalkane diols such as cyclohexane 1,4-diol or cyclohexane 1,4-dimethylol.
  • the dicarboxylic acids are primarily isophthalic acid, naphthalene-2,6-dicarboxylic acid and adipic and sebacic acid. Mixtures of these and small proportions of polyfunctional alcohols and carboxylic acids are of course also possible.
  • organic or inorganic additives The effect of the method according to the invention is of course most effective when the polyester has little or no dyes or color pigments such as that
  • the grain geometry of the polyester can range from coarse powder to various types of granules or chips.
  • FIG. 1 shows the block diagram of the method according to the invention
  • the entire crystallization temperature range from 180 ° C to 110 ° C was investigated using a series of tests (Table 2, Nos. 1 to 8).
  • Table 2 Nos. 1 to 8
  • the raw PET granulate from Table 1 with 3.5 mol% diethylene glycol was used.
  • the initial values of the amorphous raw material were:
  • the degree of crystallinity was calculated from the measured density using the known equation. It is
  • the solvent is a mixture of the same
  • the relative viscosity R.V. is the ratio of the viscosity of the solution to that of the pure solvent.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Polyesters Or Polycarbonates (AREA)

Abstract

L'invention concerne un procédé de réduction de la valeur de jaune d'un granulat polyester postcondensé (par exemple pour les bouteilles pour boissons). Selon l'invention, la cristallisation de la matière polyester (copolyester ou homo-PET) s'effectue à une température inférieure à 145 °C. Le traitement thermique suivant s'opère au moyen des dispositifs de postcondensation connus à des températures extrêmement plus élevées (postcondensation en phase solide). En comparaison de la cristallisation à des températures très élevées, il s'opère une réduction drastique de l'indice de jaune jusqu'au produit fini du processus en phase solide.
PCT/CH1993/000157 1992-07-06 1993-06-18 Procede de reduction de l'indice de jaune d'un granulat polyester postcondense WO1994001484A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH2131/92-2 1992-07-06
CH213192 1992-07-06

Publications (1)

Publication Number Publication Date
WO1994001484A1 true WO1994001484A1 (fr) 1994-01-20

Family

ID=4226610

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CH1993/000157 WO1994001484A1 (fr) 1992-07-06 1993-06-18 Procede de reduction de l'indice de jaune d'un granulat polyester postcondense

Country Status (2)

Country Link
CN (1) CN1082063A (fr)
WO (1) WO1994001484A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000043182A1 (fr) * 1999-01-22 2000-07-27 Bühler AG Dispositif et procede pour traiter une matiere plastique
WO2000046004A1 (fr) * 1999-02-04 2000-08-10 Bühler AG Procede de valorisation de matiere plastique
KR200340118Y1 (ko) * 2003-10-17 2004-01-31 동일고무벨트주식회사 교좌장치
KR100466961B1 (ko) * 2002-01-29 2005-01-24 이종환 회전 수평조절용 솔 플레이트
AT502958B1 (de) * 2005-12-05 2011-07-15 Starlinger & Co Gmbh Anlage zur wärmebehandlung von kunststoffmaterial

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104059220A (zh) * 2014-07-16 2014-09-24 珠海华润包装材料有限公司 一种pet固相缩聚装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1905677A1 (de) * 1968-03-26 1969-10-09 Snia Viscosa Verfahren zum Kristallisieren von Polyestern
CA849098A (en) * 1970-08-11 J. Kibler Charles Process for solid phase polymerization of polyethylene terephthalate
EP0269583A2 (fr) * 1986-11-21 1988-06-01 COBARR S.p.A. Méthode de préparation de résines de polyesters de haut poids moléculaire

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA849098A (en) * 1970-08-11 J. Kibler Charles Process for solid phase polymerization of polyethylene terephthalate
DE1905677A1 (de) * 1968-03-26 1969-10-09 Snia Viscosa Verfahren zum Kristallisieren von Polyestern
EP0269583A2 (fr) * 1986-11-21 1988-06-01 COBARR S.p.A. Méthode de préparation de résines de polyesters de haut poids moléculaire

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 12, no. 50 (C-476)16. Februar 1988 *
PATENT ABSTRACTS OF JAPAN vol. 9, no. 88 (C-276)17. April 1985 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000043182A1 (fr) * 1999-01-22 2000-07-27 Bühler AG Dispositif et procede pour traiter une matiere plastique
US6716959B2 (en) 1999-01-22 2004-04-06 Buehler Ag Device and method for treating plastic material
WO2000046004A1 (fr) * 1999-02-04 2000-08-10 Bühler AG Procede de valorisation de matiere plastique
KR100466961B1 (ko) * 2002-01-29 2005-01-24 이종환 회전 수평조절용 솔 플레이트
KR200340118Y1 (ko) * 2003-10-17 2004-01-31 동일고무벨트주식회사 교좌장치
AT502958B1 (de) * 2005-12-05 2011-07-15 Starlinger & Co Gmbh Anlage zur wärmebehandlung von kunststoffmaterial

Also Published As

Publication number Publication date
CN1082063A (zh) 1994-02-16

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