POLYESTER CARBONATES FROM ALIPHATIC DIACIDS AND ALIPHATIC DIOLS, AND PROCESS FOR THE PRODUCTION THEREOF

Abstract

The present invention relates to a process for preparing a polyester carbonate on the basis of aliphatic diacids and aliphatic diols and to the polyester carbonate prepared according to the process and to a moulding mass and moulding body containing the polyester carbonate. The process according to the invention is a direct synthesis in which all structural elements forming the subsequent polyester carbonate are already present as monomers in the first process step and in which two catalysts are used.

Claims

1.-15. (canceled)

16. A process for producing a polyester carbonate by melt transesterification, comprising the steps of: (i) reacting at least at least one linear aliphatic dicarboxylic acid and/or at least one cycloaliphatic dicarboxylic acid with at least one diaryl carbonate in the presence of at least one aliphatic dihydroxy compound and in the presence of a first catalyst and/or a second catalyst, (ii) subjecting the mixture obtained from process step (i) to a further condensation in the presence of the first catalyst and the second catalyst, at least with removal of the chemical compound eliminated in the condensation, wherein the first catalyst is at least one tertiary nitrogen base, wherein the second catalyst is at least one basic alkali metal salt, and wherein the proportion of alkali metal cations in process step (ii) is 0.0008% to 0.0030% by weight based on all components used in process step (i).

17. The process as claimed in claim 16, wherein the at least one aliphatic dihydroxy compound is selected from the group consisting of cyclohexane-1,2-diol, cyclohexane-1,3-diol, cyclohexane-1,4-diol, cyclohexane-1,2-dimethanol, cyclohexane-1,3-dimethanol, cyclohexane-1,4-dimethanol, tricyclodecanedimethanol, 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, 2,2-bis(4-hydroxycyclohexyl)propane, tetrahydrofuran-2,5-dimethanol, and 1,4:3,6-dianhydrohexitols such as isomannide, isoidide and isosorbide.

18. The process as claimed in claim 17, wherein the at least one aliphatic dihydroxy compound is isosorbide.

19. The process as claimed in claim 16, wherein the at least one linear aliphatic dicarboxylic acid and/or the at least one cycloaliphatic dicarboxylic acid is represented by the general formula (1): ##STR00011## in which A represents R.sub.3 or one of formulas (Ia) or (Ib), where R.sub.3 represents a linear alkylene group having 3 to 16 carbon atoms, and this alkylene group may optionally be mono- or polysubstituted or ##STR00012## in which B in each case independently represents a CH.sub.2 group, O or S, R.sub.1 in each case independently represents a single bond or an alkylene group having 1 to 10 carbon atoms, and R.sub.2 in each case independently represents an alkyl group having 1 to 10 carbon atoms, n is a number between 0 and 3, m is a number between 0 and 6, and “*” indicate the positions at which the carboxylic acid groups in formula (1) are present.

20. The process as claimed in claim 19, wherein R.sub.3 is selected from —CH.sub.2—CH.sub.2—CH.sub.2—, —CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—, —CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—, —CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—, —CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—, —CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—CH.sub.2—, —CH.sub.2—C(CH.sub.3).sub.2—CH.sub.2—, —CH.sub.2—CH(CH.sub.3)—CH.sub.2—C(CH.sub.3).sub.2—, —CH.sub.2—C(CH.sub.3).sub.2—CH.sub.2—CH(CH.sub.3)—, and —CH(CH.sub.3)—CH.sub.2—CH.sub.2—C(CH.sub.3).sub.2— and that the cycloaliphatic dicarboxylic acid is hydrogenated dimer fatty acid or a compound of formula (IIa), (IIb) or mixtures thereof. ##STR00013## in which B in each case independently represents a CH.sub.2 group or a heteroatom selected from the group consisting of O and S, and n is a number between 0 and 3.

21. The process as claimed in claim 20, wherein the at least one cycloaliphatic dicarboxylic acid is cyclohexane-1,4-dicarboxylic acid.

22. The process as claimed in claim 16, wherein the at least one diaryl carbonate is selected from the group consisting of a compound of formula (2). ##STR00014## in which R, R′, and R″ may each independently be identical or different and represent hydrogen, optionally branched C1-C34 alkyl, C7-C34 alkylaryl, C6-C34 aryl, a nitro group, a carbonyl-containing group, a carboxyl-containing group or a halogen group.

23. The process as claimed in claim 22, wherein the at least one diaryl carbonate is diphenyl carbonate.

24. The process as claimed in claim 16, wherein the first catalyst is selected from the group consisting of bases derived from guanidine, 4-dimethylaminopyridine, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 1,5,7-triazabicyclo[5.4.0]dec-5-ene and mixtures of these substances.

25. The process as claimed in claim 16, wherein the first catalyst is used in an amount of from 0.002% to 0.1% by weight based on all components used in process step (i).

26. The process as claimed in claim 16, wherein the second catalyst is selected from the group consisting of sodium phenoxide, lithium phenoxide, sodium hydroxide, lithium hydroxide, sodium benzoate, lithium benzoate, and mixtures thereof.

27. The process as claimed in claim 16, wherein the chemical compound eliminated in the condensation is removed in process step (ii) by means of reduced pressure.

28. A polyester carbonate obtainable by the process as claimed in claim 16.

29. A molding compound comprising a polyester carbonate as claimed in claim 28.

30. A molding comprising a polyester carbonate as claimed in claim 28.

Description

EXAMPLES

Materials Used:

[0145] Cyclohexanedicarboxylic acid: Cyclohexane-1,4-dicarboxylic acid; CAS 1076-97-7 99%; Tokyo Chemical Industries, Japan, abbreviated to CHDA. The CHDA contained less than 1 ppm sodium by elemental analysis.

[0146] Diphenyl carbonate: Diphenyl carbonate, 99.5%, CAS 102-09-0; Acros Organics, Geel, Belgium, abbreviated to DPC

[0147] 4-Dimethylaminopyridine: 4-Dimethylaminopyridine; >98.0%; purum; CAS 1122-58-3; Sigma-Aldrich, Munich, Germany, abbreviated to DMAP

[0148] Isosorbide: Isosorbide (CAS: 652-67-5), 99.8%, Polysorb PS A; Roquette Freres (62136 Lestrem, France); abbreviated to ISB

[0149] Sodium benzoate: Sodium benzoate (CAS 532-32-1); Sigma-Aldrich, Munich, Germany

[0150] 3,3-Dimethylglutaric acid: (CAS 4839-46-7) ABCR GmbH, Karlsruhe, Germany

[0151] Lithium hydroxide (LiOH): (CAS 1310-66-3); Sigma-Aldrich, Munich, Germany

Analytical Methods:

Solution Viscosity

[0152] Determination of solution viscosity: The relative solution viscosity (ηrel; also referred to as eta rel) was determined using an Ubbelohde viscometer in dichloromethane at a concentration of 5 g/l at 25° C. The determination was carried out in accordance with DIN 51562-3; 1985-05. In this determination, the transit times of the polyester carbonate under investigation are measured by the Ubbelohde viscometer in order to then determine the difference in viscosity between the polymer solution and its solvent. For this, the Ubbelohde viscometer undergoes an initial calibration through measurement of the pure solvents dichloromethane, trichloroethylene, and tetrachlorethylene (always performing at least 3 measurements, but not more than 9 measurements). This is followed by the calibration proper with the solvent dichloromethane. The polymer sample is then weighed out, dissolved in dichloromethane and the flow time for this solution then determined in triplicate. The average of the flow times is corrected via the Hagenbach correction and the relative solution viscosity calculated.

Example 1: 10 ppm Na

[0153] A flask with a short-path separator was charged with 17.20 g (0.10 mol) of cyclohexane-1,4-dicarboxylic acid, 29.83 g (0.204 mol) of isosorbide, 64.30 g (0.3 mol) of diphenyl carbonate, 0.0111 g of DMAP (4-dimethylaminopyridine; 100 ppm based on the starting materials CHDA, DPC, and ISB), and 50.2 μl of an aqueous solution of sodium benzoate (141.4 g/l), corresponding to approx. 10 ppm Na. The mixture was freed of oxygen by evacuating and releasing the vacuum with nitrogen four times. The mixture was melted and heated to 160° C. at standard pressure with stirring. The mixture was stirred at 160° C. for 50 minutes, at 175° C. for 50 minutes, at 190° C. for 30 minutes, and at 205° C. for 50 minutes. During this operation, carbon dioxide continuously evolves. On cessation of CO.sub.2 evolution, the bath temperature is adjusted to 220° C. After a further 20 minutes, a negative pressure is applied. The pressure is lowered to 10 mbar over a 30-minute period. During this operation, phenol is continuously removed. The mixture is stirred at 10 mbar for about 10 minutes. The pressure is then lowered to <1 mbar (approx. 0.7 mbar) and condensation continued for a further 10 minutes. Processing of the mixture was then stopped.

[0154] A light brown polymer with a solution viscosity of eta rel 1.258 was obtained.

[0155] The other examples (Ex.) and comparative examples (Comp.) were produced as stated for example 1, varying only the amounts of sodium benzoate and DMAP used. The data are summarized in Table 1. Shown in each case are the proportions by weight in ppm of DMAP and of alkali metal, based on the weights of the components used.

[0156] In all cases, both catalysts were added in process step (i). The catalysts remain in the reaction mixture completely. The proportions of DMAP and alkali metal are based on all components used in process step (i).

TABLE-US-00001 TABLE 1 DMAP [ppm] Alkali metal [ppm] eta rel Comp. 1 100 1 1.018 Comp. 2 100 5 1.103 Ex. 1 100 10 1.258 Ex. 2 100 8 1.21 Ex. 3 100 20 1.293 Comp. 3 100 50 1.41 Comp. 4 0 10 1.019

[0157] Examples 1 to 4 show that the process of the invention provides the desired polyester carbonates in the desired viscosity window. If the content of alkali ions is too low, as shown in comparative examples 1 and 2, only an inadequate increase in molecular weight can be achieved. If the alkali content is too high, as shown in comparative example 3, this results in viscosities that can practically no longer be processed. If only one catalyst is used (comparative example 4), the resulting viscosity is again too low.

[0158] Negative pressures employed in accordance with the invention;

Example 4

[0159] A flask with a short-path separator was charged with 103.2 g (0.60 mol) of cyclohexane-1,4-dicarboxylic acid, 176.35 g (1.206 mol) of isosorbide, 385.8 g (1.80 mol) of diphenyl carbonate, 0.0666 g of DMAP (4-dimethylaminopyridine; 100 ppm based on the starting materials CHDA, DPC, and ISB), and 30 ppm of sodium, in the form of an aqueous solution of sodium benzoate (same concentration as in example 1). The mixture was freed of oxygen by evacuating and releasing the vacuum with nitrogen four times. The mixture was melted and heated to 180° C. at standard pressure with stirring. Once the starting materials have melted completely, the mixture is stirred for 20 minutes. This is followed by a reduction in pressure to 240 mbar over a 25-minute period. The pressure is reduced to 140 mbar over a 40-minute period. During this operation, phenol is continuously distilled off. The vacuum in the reaction mixture is released with nitrogen and the mixture is checked to see whether CO.sub.2 evolution is still taking place. On cessation of CO.sub.2 evolution, the condensation phase (phase 2) is initiated (if CO.sub.2 evolution can still be observed at this point, wait until this ceases; a further 100 ppm of DMAP can at this point be added—this is necessary if this catalyst has been completely removed in the first stage, which may be evidenced by a sluggish polycondensation phase). The pressure is adjusted to 140 mbar and the bath temperature to 105° C. The pressure is lowered to 70 mbar over a 15-minute period. After this, the pressure is over a 50-minute period reduced to 1 mbar and the bath temperature raised to 240° C. At 1 mbar and 240° C., the mixture is stirred for a further 20 minutes. If the melt gets drawn up onto the stirrer, it is removed from the stirrer and returned to the melt. In order to do this, the vacuum in the mixture must be temporarily released. A light brown polycondensate having an eta rel of 1.32 is obtained.

[0160] Example 4 shows that the process of the invention allows the reaction time in phase 1 to be significantly reduced through application of a negative pressure. Despite the higher quantities used, it was possible to shorten phase 1 significantly.

Example 5: 3,3-Dimethylglutaric acid

[0161] A three-necked flask with a short-path separator was charged with 24.63 g (0.1685 mol) of isosorbide, 8.01 g (0.05 mol) of 3,3-dimethylglutaric acid, 46.36 g (0.2165 mol) of diphenyl carbonate, 100 ppm (0.079 g) of DMAP, and 30 ppm of Li (as an aqueous solution of LiOH by means of a stock solution (100.00 g/L->0.078 mL). The contents of the flask were freed of oxygen by evacuating and releasing the vacuum with nitrogen four times. The mixture was heated to 160° C. and melted. After melting, the mixture was stirred at 160° C. for 45 minutes. The temperature was then increased to 225° C. in stages over a 1.5-hour period. The pressure was lowered to 500 mbar over a 30-minute period. During this operation, phenol was continuously removed. The temperature was increased to 235° C. and the pressure slowly lowered to 0.1 mbar over a 2-hour period. After stirring at 235° C. and 0.1 mbar for 10 minutes, the reaction was stopped and the melt removed.

[0162] A light-colored polymer melt having a solution viscosity of 1.256 and a glass transition temperature of 121° C. was obtained.

Example 6: Mixture of 3,3-dimethylglutaric acid and cyclohexanedicarboxylic acid

[0163] A three-necked flask with a short-path separator was charged with 29.83 g (0.2040 mol) of isosorbide, 8.01 g (0.05 mol) of 3,3-dimethylglutaric acid, 8.60 g (0.050 mol) of cyclohexanedicarboxylic acid, 64.30 g (0.30 mol) of diphenyl carbonate, 100 ppm (0.0111 g) of DMAP, and 10 ppm of Na as sodium benzoate (0.0069 g). The contents of the flask were freed of oxygen by evacuating and releasing the vacuum with nitrogen four times. The mixture was heated to 160° C. and melted. After melting, the mixture was stirred at 160° C. for 15 minutes. The temperature was increased to 175° C. and stirring continued at this temperature for 75 minutes. A further 100 ppm (0.0111 g) of DMAP was then added and the mixture stirred at 175° C. for a further 30 minutes. After the evolution of gas had ceased, the temperature was increased to 220° C. in stages over a 1.5-hour period. During this operation, phenol was continuously removed. The temperature was then increased to 230° C. and the pressure reduced to 1 mbar in stages over a 1-hour period. The mixture was stirred at 1 mbar for a further 10 minutes, after which the melt was removed.

[0164] A light-colored polymer melt having a solution viscosity of eta rel 1.24 was obtained.

[0165] Examples 5 and 6 show that linear aliphatic dicarboxylic acids and also mixtures of linear aliphatic dicarboxylic acids with cycloaliphatic dicarboxylic acids also afford a polyester carbonate having the desired and processable viscosities.