DE102008033188A1 - Process for the preparation of copolyesters, copolyesters and moldings of copolyesters - Google Patents

Abstract

The invention describes a process for the preparation of copolyesters, in particular based on a polycondensation product of terephthalic acid with ethylene glycol and propylene oxide. These copolyesters have a comparatively low melting point. A sufficiently high intrinsic viscosity for further processing can be achieved, for example, by a postcondensation.

Description

The Invention describes a process for the preparation of copolyesters, in particular based on a polycondensation product of terephthalic acid with ethylene glycol and propylene oxide. These copolyesters have one comparatively low melting point. One for further processing sufficiently high intrinsic viscosity can be, for example be achieved by a post-condensation.

The prior art describes the reaction of ethylene oxide, the lower homologue of propylene oxide, with terephthalic acid in special cylindrical reactors. Exemplary process guides include the Petrochemical Developments 146-150 (1970) and Chem. Engg. Neves 23 (1970), 42-43 called. The preparation of fiber-forming polyesters in pressure autoclaves from bifunctional components (at least 85% terephthalic acid) and ethylene oxide using ammonium salts, amines, amines or amino acids as catalyst is described in the patent 49055 (GDR) mentioned.

The reaction of pure alkylene oxides with terephthalic acid is described by the patents DE 28 01 422 A1 using catalytic amounts of nitrogenous substances together with chromium compounds and of US 37 46 744 described using polyamides, polyurethanes or formaldehyde resins as a catalyst.

propylene oxide comes as a comonomer in connection with the production of polyesters based on terephthalic acid and ethylene glycol so far not yet used.

task The present invention is a process for the preparation specifically structure-influenced polyester of the type mentioned above develop, in which sufficient for further processing steps high viscosities are achieved.

These The task becomes with respect to the procedure with the characteristics of claim 1 and with respect to the copolyester solved with the features of claim 13. claim 15 indicates moldings which are the inventive Contain copolyester. The respective dependent claims represent advantageous developments.

According to the invention thus providing a process for the preparation of copolyesters, in which at least one aromatic dicarboxylic acid with 8 to 32 carbon atoms and / or at least one aromatic dicarboxylic acid diester with 10 to 44 carbon atoms with at least one linear or branched aliphatic diol having 2 to 12 carbon atoms and at least one linear or branched aliphatic alkylene oxide mixed with 2 to 12 carbon atoms and co-condensed or is transesterified. In the event that free dicarboxylic acids are used, the polymerization reaction is thus as polycondensation too denote, in the event that dicarboxylic acid ester used to speak of transesterification. However, they are the same Mixed forms of the reaction types possible, if both free Acids and esters of dicarboxylic acids used become.

In In a preferred embodiment, the amounts of the used diols and the alkylene oxide so coordinated, that based on the sum of the at least one diol and the at least an alkylene oxide between 70 and 99.9 mol%, preferably 80 to 99.5 mol% of the at least one diol and 30 to 0.01 mol%, preferably 20 to 0.5 mol% of the at least one alkylene oxide are used. The numbers thus give the preferred mixing ratios of diol to alkylene oxide.

there it is equally preferred that at least one diol and that at least one alkylene oxide as a mixture or successively with the dicarboxylic acid and / or the dicarboxylic acid diester to react so that both randomly distributed copolymers as well as block copolymers are accessible.

preferred Dicarboxylic acids are selected from the group consisting of terephthalic acid, isophthalic acid and / or mixtures thereof, while the preferred dicarboxylic acid diesters are selected from the group consisting of aliphatic Diesters of terephthalic acid and / or isophthalic acid with aliphatic alcohols having 1 to 6 carbon atoms, preferred Dimethyl terephthalate and / or dimethyl isophthalate.

preferred to be used diols are selected from the group consisting of 1,2-ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, Cyclohexane-1,4-diemthanol and / or mixtures thereof.

advantageous Alkylene oxides are selected from the group consisting of Ethylene oxide, propylene oxide, butylene oxide and / or mixtures thereof.

In a particularly preferred embodiment relates to The present invention provides a process for producing a polyester based on a polycondensation product of terephthalic acid with ethylene glycol and propylene oxide, as well as those prepared Reaction products.

Advantageous it is also the reaction mixture before, during and / or after cocondensation or transesterification further additives selected from the group consisting of catalysts, pigments, dyes, Fillers, stabilizers, in particular phosphorus compounds, Flame retardants, lubricants, antioxidants, nanoscale fillers, silver-containing additives, in particular silver salts for antibacterial action, Scavenger for acetaldehyde reduction and / or combinations thereof add, resulting in the respective desired properties to control the copolyester targeted.

The Esterification reaction can be carried out in two alternative ways depending on whether carbonic acid diester or free carboxylic acids be used as starting materials. The individual reaction stages (esterification and polycondensation) can successively in a reactor be carried out (batch process) or on continuous Systems divided into corresponding reaction stages / plant components (such as paste mixers, pre-esterification, esterification, precondensation, Polycondensation, post-condensation, etc.) are performed.

For the esterification or polycondensation, it is advantageous already for this type of reaction known catalysts in the usual use of material quantities. In particular, here are catalysts in question, which are selected from the group Ti salts, Ti organyls, in particular titanium tetravutylate, Ge compounds, Sb compounds, in particular antimony oxide, antimony acetate, antimony glycolate, Co compounds and / or Co salts, in particular Co acetate, tin compounds, Alkylamines, especially primary, secondary and / or tertiary amines, such as. Triethylamine, tributylamine, Pyridine, quaternary ammonium salts, salts of amines or amides and / or combinations thereof.

Especially Good conversion rates and yields arise when the at least a dicarboxylic acid and / or the at least one dicarboxylic acid diester with respect to the sum of the at least one diol and the at least one alkylene oxide in a molar ratio between 0.7: 1 to 1: 1, preferably between 0.75: 1 and 0.85: 1 is used.

preferred Temperature ranges of the polycondensation or transesterification reaction lie at temperatures between 190 ° C and 290 ° C, preferably between 200 to 280 ° C, more preferably between 230 and 240 ° C.

For the lead of the procedure come two preferred alternative Variants in question. On the one hand, the process can be carried out in one stage be, where the intrinsic viscosity of the copolyester adjusted to 0.91 dL / g, preferably between 0.78 and 0.91 dL / g On the other hand, it is also possible to use the method perform in two stages, first in one Precondensation stage of copolyesters up to an intrinsic Viscosity between 0.46 and 0.7 dL / g, preferably between 0.55 and 0.7 dL / g is copolymerized and transesterified and thereto then in a post-condensation stage the intrinsic Viscosity of the copolyester in the post-condensation stage increased to 0.91 dL / g, preferably to 0.78 and 0.91 dL / g becomes.

at the two-part procedure is advantageous if the precondensation step at pressures between 1 and 20 bar, preferably between 5 and 12 bar and / or the post-condensation step at pressures between 0.1 mbar and 0.1 bar, preferably between 0.1 mbar and 10 mbar is performed.

According to the invention also provided a copolyester, which according to the previously described inventive method can be produced.

The polyesters of the invention are characterized a comparatively low melting point of about 200 ° C to about 260 ° C, preferably 230 ° C to 260 ° C. out. Due to the lowered melting point occur unwanted Secondary and degradation reactions during processing in reduced Extent on. In addition, energy costs are reduced.

Polyesters of the type described above have an intrinsic viscosity of 0.46 to 0.7 dL / g. An increase in intrinsic viscosity, as in the processing of the polyester into bottles or mold may be carried out in the polyesters according to the invention by a special form of post-condensation under vacuum at temperatures of 190 ° C to 240 ° C, preferably from 200 ° C to 230 ° C.

According to the invention also provided moldings which are an inventive Include copolyesters. The moldings are in particular selected from foils, bottles, filaments, foil-cast Moldings, injection-molded parts and deep-drawn moldings.

The The following example is intended to explain the invention further:

Example: Modification with 10 mol% of propylene oxide

600.00 g of terephthalic acid (3.61 mol), 262.27 g of ethylene glycol (4.23 mol) and 27.27 g of propylene oxide (0.47 mol) in a 2 l stainless steel reactor with catalysis of triethylamine at a pressure of 10 bar esterified. The resulting oligomer mixture is polycondensed under the catalysis of Sb ₂ O ₃ to the copolyester. The polyester is postcondensed under vacuum at 230 ° C for 16 h. The following table shows the influence of the postcondensation on the intrinsic viscosity. Table 1: With 10 mol% modified copolyester before the postcondensation With 10 mol .-% modified copolyester after the postcondensation Intrinsic viscosity 0.61 0.95

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DD 49055 [0002]
• DE 2801422 A1 [0003]
• US 3746744 [0003]

Cited non-patent literature

• Petrochemical Developments 146-150 (1970) and Chem. Engg. Neves 23 (1970), 42-43 [0002]

Claims (15)

Process for the preparation of copolyesters the at least one aromatic dicarboxylic acid with 8 to 32 carbon atoms and / or at least one aromatic Dicarboxylic acid diesters having 10 to 44 carbon atoms with at least a linear or branched aliphatic diol having 2 to 12 Carbon atoms and at least one linear or branched one aliphatic alkylene oxide having 2 to 12 carbon atoms mixed and copolycondensed or transesterified. Method according to claim 1, characterized in that that based on the sum of the at least one diol and the at least an alkylene oxide between 70 and 99.9 mol%, preferably 80 to 99.5 mol% of the at least one diol and 30 to 0.1 mol%, preferably 20 to 0.5 mol% of the at least one alkylene oxide are used. Method according to one of the preceding claims, characterized in that the at least one diol and the at least an alkylene oxide as a mixture or successively with the dicarboxylic acid and / or dicarboxylic acid diester mixed and copolycondensed become. Method according to one of the preceding claims, characterized in that the at least one dicarboxylic acid is selected from the group consisting of terephthalic acid, Isophthalic acid and / or mixtures thereof and / or the at least one dicarboxylic acid diester selected is from the group consisting of diesters of terephthalic acid and / or isophthalic acid with aliphatic alcohols 1 to 6 carbon atoms, preferably dimethyl terephthalate and / or Dimethyl. Method according to one of the preceding claims, characterized in that the diol is selected from the group consisting of 1,2-ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, cyclohexane-1,4-dimethanol and / or mixtures thereof. Method according to one of the preceding claims, characterized in that the alkylene oxide is selected is selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide and / or mixtures thereof. Method according to one of the preceding claims, characterized in that the reaction mixture before, during and / or after the cocondensation or transesterification further additives, selected from the group consisting of catalysts, Pigments, dyes, fillers, stabilizers, in particular Phopsphor compounds, flame retardants, lubricants, antioxidants, nanoscale fillers, silver-containing additives, in particular Silver salts for antibacterial action, scavenger to Acetaldehydre reduction and / or combinations thereof are added. Method according to the preceding claim, characterized that the catalyst is selected from the group consisting Ti salts, Ti organyls, in particular titanium tetrabutoxide, Ge compounds, Sb compounds, in particular antimony oxide, antimony acetate, antimony glycolate, co-compounds and / or co-salts, in particular cobalt acetate, tin compounds, Alkylamines, especially primary, secondary and / or tertiary amines, such as. Triethylamine, tributylamine, pyridine, quaternary ammonium salts, salts of amines or amides and / or combinations thereof. Method according to one of the preceding claims, characterized in that the at least one dicarboxylic acid and / or at least one dicarboxylic acid diester the sum of the at least one diol and the at least one alkylene oxide in a molar ratio between 0.7: 1 to 1: 1, preferred between 0.75: 1 and 0.85: 1 is used. Method according to one of the preceding claims, characterized in that the copolycondensation or transesterification at temperatures between 190 ° C and 290 ° C, preferably between 200 to 280 ° C, more preferably between 230 and 240 ° C is performed. Method according to one of the preceding claims, characterized in that it a) is carried out in one stage, wherein the intrinsic viscosity of the copolyester to up to 0.91 dL / g, preferably between 0.78 and 0.91 dL / g is set, or b) is carried out in two stages, wherein initially in a precondensation stage up to an intrinsic viscosity of the resulting copolyester between 0.46 and 0.7 dL / g, preferably between 0.55 and 0.7 dL / g co is polycondensed or transesterified, and in a subsequent post-condensation step, the intrinsic viscosity of the copolyester to up to 0.91 dL / g, preferably 0.78 and 0.91 dL / g is increased. Method according to the preceding claim, characterized in that, in the two-stage process, the precondensation step at pressures between 1 and 20 bar, preferably between 5 and 12 bar and / or the post-condensation step at pressures between 0.1 mbar and 0.1 bar, preferably between 0.1 mbar and 10 mbar is performed. Copolyester, preparable by a process according to one of the preceding claims. Copolyester according to the preceding claim by a melting point between 200 and 260 ° C, preferably between 230 and 260 ° C. Shaped body containing a copolyester according to one of claims 13 to 14, in particular a shaped body selected from the group consisting of films, bottles, Filaments, foil moldings, molded parts, injection-molded parts and deep-drawn moldings.