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
  • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
  • C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
  • C08G63/16—Dicarboxylic acids and dihydroxy compounds
  • C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
  • C08G63/181—Acids containing aromatic rings
  • C08G63/183—Terephthalic acids
• • 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

Definitions

• the invention relates to a method for producing polyethylene terephthalate (PET) modified with o-phthalic acid units.
• PET polyethylene terephthalate
• Polyethylene terephthalate is modified with various comonomers, in particular as a starting material for the production of packaging materials, in order to achieve favorable performance properties.
• Substances that break the chain orientation are preferably added. This achieves a lower melting point, which is important for the formation of by-products (such as acetaldehyde) during production and processing, and a lower thermal crystallization rate.
• the lower crystallization speed allows the production of semi-finished products for special areas of application.
• phthalic anhydride in PET production as a catalyst (DE 2 126 217, DE 2 166 285, JP 49 013 249, JP 50 062 245, JP 52 124 098) and for end group modification (EP 51 553 and SU 994 490) known.
• JP 08 188 919 and JP 06 184 415 deal with the use of phthalic anhydride in the production of polyethylene terephthalate fibers.
• the use of phthalic anhydride in the esterification is problematic both due to the pronounced tendency of this substance to sublimate and also due to the tendency to form cyclic oligomers with a comparatively low boiling point. This is associated with high losses of phthalic acid in the esterification and in the polycondensation phase.
• the Romanian patent RO 104 034 protects the production of polyethylene terephthalate with a content of 25-55% by mass of phthalic acid units.
• the polycondensation of bis (hydroxyethyl) terephthalate is described with a Bis (hydroxyethyl) phthalate.
• the phthalate is synthesized by the reaction of ethylene glycol with phthalic anhydride with a molar excess of ethylene glycol to terephthalic acid of 3-6: 1 and in the presence of zinc acetate as a catalyst.
• a phthalate produced in this way cannot be used in the synthesis of packaging materials because the process-related extremely high content of diethylene glycol (> 20%) of this ester lowers the glass transition temperature of the modified polyethylene terephthalate very far.
• the catalyst also has a disruptive effect on the polyester at high temperatures, since zinc acetate catalyzes the thermal decomposition of polyethylene terephthalate.
• the copolyesters produced in this way are therefore only used as adhesives.
• GB 1 060 401 describes the synthesis of stable block copolyesters with the addition of phosphorus compounds.
• DE 2 706 128 protects the use of phthalic acid esters as plasticizers for polyethylene terephthalate.
• the esterification of the end groups of these phthalic esters with monofunctional alcohols (eg nonanol) prevents incorporation into the PET.
• the object of the invention is a process for the production of polyethylene terephthalate modified with o-phthalic acid units while avoiding high phthalic acid losses during the esterification and the polycondensation while maintaining the favorable application properties due to phthalic acid.
• the object was achieved in that an uncatalyzed precondensate of phthalic anhydride and ethylene glycol is added in the esterification and / or polycondensation stage, in which ethylene glycol is present in a molar excess of 2 to 3.5, preferably 2.5 to 3 on the phthalic anhydride is used.
• precondensate must be prepared from phthalic anhydride and ethylene glycol with an excess of ethylene glycol.
• An important advantage of the invention is that phthalic anhydride available on a large industrial scale is used for the modification of PET.
• Table 1 contains an overview of the oligomers identified.
• This precondensate of phthalic anhydride and ethylene glycol is unsuitable for installation under polycondensation conditions due to the very high content of relatively volatile cyclic esters.
• the products were examined by NMR spectroscopy for the phthalic acid content.
• Example 5 In an experimental apparatus and after an experimental procedure analogous to Example 5, the phthalic anhydride was only added after the esterification stage. After the addition, the mixture was stirred under pressure for 10 min. The polycondensation was then carried out analogously to Example 1.
• Example 5 The test apparatus and procedure corresponded to Example 5. After the phthalic acid comonomer had been added, the mixture was stirred under pressure for 60 min. The products were examined by NMR spectroscopy for the phthalic acid content.
• polyester synthesized in this way meets the requirements for the production of semi-finished products for special applications with regard to glass transition temperature (76-81 ° C), melting temperature (230-250 ° C) and a modified crystallization behavior.

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• 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)

Applications Claiming Priority (3)

Publications (1)

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Country Status (10)

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Family Cites Families (21)

• 1999
  • 1999-07-02 DE DE19930705A patent/DE19930705A1/de not_active Withdrawn
• 2000
  • 2000-06-10 MX MXPA01013409A patent/MXPA01013409A/es unknown
  • 2000-06-10 EP EP00949089A patent/EP1320568A2/de not_active Withdrawn
  • 2000-06-10 US US10/018,535 patent/US6515080B1/en not_active Expired - Fee Related
  • 2000-06-10 JP JP2001508247A patent/JP2003504436A/ja active Pending
  • 2000-06-10 DE DE10081855T patent/DE10081855D2/de not_active Ceased
  • 2000-06-10 CA CA002377603A patent/CA2377603A1/en not_active Abandoned
  • 2000-06-10 AU AU62597/00A patent/AU6259700A/en not_active Abandoned
  • 2000-06-10 WO PCT/DE2000/001926 patent/WO2001002461A2/de not_active Application Discontinuation
  • 2000-06-30 TW TW089112951A patent/TW553973B/zh active
  • 2000-06-30 AR ARP000103360A patent/AR032744A1/es unknown

Non-Patent Citations (1)

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