Polyester Carbonates on the Basis of Cycloaliphatic Diacids, 1,4:3,6-Dianhydrohexitol and Specific Amounts of an Additional Aliphatic Dihydroxy Compound

Abstract

The present invention relates to a process for preparing a polyester carbonate on the basis of cycloaliphatic diacids and at least one 1,4:3,6-dianhydrohexitol and at least one additional aliphatic dihydroxy compound, to the polyester carbonate prepared according to the process and to a molding compound and a molding 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 present as monomers already in the first process step. It is characterized in that a specific ratio of 1,4:3,6-dianhydrohexitol and the at least one additional aliphatic dihydroxy compound is advantageous.

Claims

1. A process for producing a polyester carbonate by melt transesterification, comprising the steps of: (i) reacting at least one cycloaliphatic dicarboxylic acid with at least one diaryl carbonate using at least one catalyst and in the presence of a mixture of dihydroxy compounds comprising (A) at least one 1,4:3,6-dianhydrohexitol and (B) at least one further aliphatic dihydroxy compound, and (ii) subjecting the mixture obtained from step (i) of the process to further condensation, at least with removal of the chemical compound eliminated in the condensation, wherein the mixture of dihydroxy compounds comprises 98 mol % to 75 mol % of component (A) and 2 mol % to 25 mol % of component (B), in each case based on the sum of components (A) and (B).

2. The process as claimed in claim 1, wherein the molar ratio of all aliphatic dihydroxy compounds present in step (i) of the process to all cycloaliphatic dicarboxylic acids present in step (i) of the process prior to the reaction in step (i) of the process is 1:0.6 to 1:05.

3. The process as claimed in claim 1, wherein the reaction in process step (i) is carried out in the presence of at least one first catalyst and/or a second catalyst and that the condensation in process step (ii) is carried out at least in the presence of the first catalyst and the second catalyst, wherein the first catalyst is at least one tertiary nitrogen base, the second catalyst is at least one basic compound, and wherein the proportion of alkali metal cations in process step (ii) is 0.0008% to 0.0030% by weight based on all the components used in process step (i).

4. The process as claimed in claim 1, wherein the at least one further aliphatic dihydroxy compound has the chemical formula (I):
HO—X—OH  (I), in which X is a linear alkylene group having 2 to 22 carbon atoms, which may optionally be interrupted by at least one heteroatom, a branched alkylene group having 4 to 20 carbon atoms, which may optionally be interrupted by at least one heteroatom, or a cycloalkylene group having 4 to 20 carbon atoms, which may optionally be interrupted by at least one heteroatom.

5. The process as claimed in claim 4, wherein the at least one further 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, 2,2-bis(4-hydroxycyclohexyl)propane, tetrahydrofuran-2,5-dimethanol, 2-butyl-2-ethylpropane-1,3-diol, 2-(2-hydroxyethoxy)ethanol, 2,2,4,4-tetramethylcyclobutane-1,3-diol, 2,2,4-trimethylpentane-1,3-diol, 2,2-dimethylpropane-1,3-diol, cyclobutane-1,1-diyldimethanol, 8-(hydroxymethyl)-3-tricyclo[5.2.1.02,6]decanyl]methanol, propane-1,2-diol, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, octane-1,8-diol, and any desired mixtures thereof.

6. The process as claimed in claim 1, wherein the at least one 1,4:3,6-dianhydrohexitol is isosorbide.

7. The process as claimed in claim 1, wherein the at least one cycloaliphatic dicarboxylic acid is selected from a compound of the chemical formula (IIa), (IIb) or mixtures thereof ##STR00005## where B in each case independently represents a CH.sub.2 group or a heteroatom selected from the group consisting of O and S, R.sub.1 in each case independently represents a single bond or a linear alkylene group having 1 to 10 carbon atoms, and n is a number between 0 and 3.

8. The process as claimed in claim 7, wherein the at least one cycloaliphatic dicarboxylic acid is selected from the group consisting of cyclohexane-1,4-dicarboxylic acid, cyclohexane-1,3-dicarboxylic acid, cyclohexane-1,2-dicarboxylic acid, tetrahydrofuran-2,5-dicarboxylic acid, tetrahydrodimethylfuran-2,5-dicarboxylic acid, decahydronaphthalene-2,4-dicarboxylic acid, decahydronaphthalene-2,5-dicarboxylic acid, decahydronaphthalene-2,6-dicarboxylic acid, and decahydronaphthalene-2,7-dicarboxylic acid.

9. The process as claimed in claim 1, wherein the at least one diaryl carbonate is selected from the group consisting of a compound of formula (2) ##STR00006## where 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.

10. The process as claimed in claim 3, 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[4.4.0]dec-5-ene and mixtures of these substances.

11. The process as claimed in claim 1, wherein the at least one catalyst is used in an amount of from 0.002% to 0.1% by weight based on all components used in process step (i).

12. The process as claimed in claim 3, wherein the second catalyst is selected from the group consisting of inorganic or organic alkali metal salts and inorganic or organic alkaline earth metal salts.

13. A polyester carbonate obtained by the process as claimed in claim 1.

14. A molding compound comprising a polyester carbonate as claimed in claim 13.

15. A molding comprising a polyester carbonate as claimed in claim 13.

16. The process as claimed in claim 3, wherein the second catalyst is a basic alkali metal salt.

17. The process as claimed in claim 4, wherein the cycloalkylene group contains more than one ring and may in each case optionally be branched.

18. The process as claimed in claim 1, wherein the mixture of dihydroxy compounds comprises 96 mol % to 82 mol %, of component (A) and 4 mol % to 18 mol % of component (B), in each case based on the sum of components (A) and (B).

19. The process as claimed in claim 2, wherein the molar ratio of all aliphatic dihydroxy compounds present in step (i) of the process to all cycloaliphatic dicarboxylic acids present in step (i) of the process prior to the reaction in step (i) of the process is 1:0.5 to 1:0.15.

Description

EXAMPLES

[0102] Materials Used:

[0103] 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.

[0104] Diphenyl carbonate: Diphenyl carbonate, 99.5%, CAS 102-09-0; Acros Organics, Geel, Belgium, abbreviated to DPC

[0105] 4-Dimethylaminopyridine: 4-Dimethylaminopyridine; ≥98.0%; purum; CAS 1122-58-3; Sigma-Aldrich, Munich, Germany, abbreviated to DMAP

[0106] Isosorbide: Isosorbide (CAS: 652-67-5), 99.8%, Polysorb PS A; Roquette Freres (62136 Lestrem, France); abbreviated to ISB

[0107] Lithium hydroxide monohydrate (CAS: 1310-66-3); >99.0%; Sigma-Aldrich

[0108] 2-Butyl-2-ethylpropane-1,3-diol: CAS No. 115-84-4; Aldrich (abbreviated to BEPD)

[0109] 2,2,4,4-Tetramethylcyclobutane-1,3-diol: 98% (CAS: 3010-96-6); ABCR (abbreviated to TMCBD)

[0110] 2,2,4-Trimethylpentane-1,3-diol; CAS No.: 144-19-4; Aldrich (abbreviated to TMPD)

[0111] Neopentyl glycol (2,2-dimethylpropane-1,3-diol); CAS: 126-30-7; Aldrich (abbreviated to NPG)

[0112] Butane-1,4-diol: CAS: 110-63-4; Merck 99%; (abbreviated to BDO)

[0113] Cyclohexane-1,4-dimethanol CAS: 105-08-8, Aldrich 99% (abbreviated to CHDM)

[0114] Dodecane-1,12-diol: CAS: 5675-51-4, Aldrich 99% (abbreviated to DDD)

[0115] Analytical Methods:

[0116] Solution Viscosity

[0117] The relative solution viscosity (ηrel; also referred to as eta rel) was determined in dichloromethane at a concentration of 5 g/l at 25° C. using an Ubbelohde viscometer. 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.

[0118] Determination of the Glass Transition Temperature

[0119] The glass transition temperature was determined by differential scanning calorimetry (DSC) in accordance with standard DIN EN ISO 11357-1:2009-10 and ISO 11357-2:2013-05 at a heating rate of 10 K/min under nitrogen with determination of the glass transition temperature (Tg) measured as the point of inflection in the second heating run. MALDI-TOF-MS

[0120] The sample was dissolved in chloroform. The matrix used was Dithranol with LiCl. The sample was analyzed in positive reflector and linear modes.

Comparative Example 1 (Experiment without Additional Diol)

[0121] 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 115 l of an aqueous solution of lithium hydroxide (100 g/1), corresponding to approx. 30 ppm Li. 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 40 minutes, at 175° C. for 60 minutes, at 190° C. for 30 minutes, and at 205° C. for 10 minutes. During this operation, carbon dioxide was continuously evolved. On cessation of CO.sub.2 evolution, the bath temperature was adjusted to 220° C. After a further 20 minutes, a negative pressure was applied. The pressure was lowered to 10 mbar over a 30-minute period. During this operation, phenol was continuously removed. The mixture was stirred at 10 mbar for about 10 minutes. The pressure was then lowered to <1 mbar (approx. 0.7 mbar) and the condensation continued for a further 10 minutes. Processing of the mixture was then stopped.

[0122] A light yellow polymer having a solution viscosity of eta rel 1.33 was obtained.

[0123] The other examples (Ex.) and comparative examples (Comp.) were carried out as stated for comparative example 1. In a departure from example 1, the aliphatic diols specified in Table 1 were also placed in the flask with a short-path separator together with all the other monomers forming the polymer and the catalyst.

TABLE-US-00001 TABLE 1 Comp. Inv. Inv. Inv. Inv. Inv. Inv. Inv. Inv. 1 1 2 3 4 5 6 7 8 Molar ratio 33/67/0 33/64/3 33/60/7 33/57/10 33/64/3 33/57/10 33/60/7 33/64/3 33/64/3 CHDA/ISB/ HO—R—OH Ratio total approx. approx. approx. approx. approx. approx. approx. approx. approx. diols:CHDA 1:0.5 1:0.5 1:0.5 1:0.5 1:0.5 1:0.5 1:0.5 1:0.5 1:0.5 mol % 0 5 10 15 5 15 10 5 5 HO—R—OH CHDA (mol) 0.1 0.2 0.2 0.2 0.2 0.2 0.1 0.1 0.1 approx. HO—R—OH 0 0.02 0.04 0.06 0.02 0.06 0.02 0.01 0.01 approx. TMPD TMPD TMPD NPG NPG BEPD BEPD TMCBD (mol) DPC (mol) 0.3 0.6 0.6 0.6 0.6 0.6 0.3 0.3 0.3 approx. ISB (mol) 0.2 0.38 0.36 0.34 0.38 0.34 0.18 0.19 0.19 approx. Eta rel 1.33 1.383 1.362 1.647 1.413 1.446 1.501 1.474 1.434 Glass 151 144 146 138 150 147 133 142 154 transition temperature in ° C. Inv. Inv. Inv. Inv. Comp. Comp. Comp. 9 10 11 12 2 3 4 Molar ratio 33/57/10 33/64/3 33/64/3 33/57/10 33/33.5/33.5 33/33.5/33.5 33/33.5/33.5 CHDA/ISB/ HO—R—OH Ratio total approx. approx. approx. approx. approx. approx. approx. diols:CHDA 1:0.5 1:0.5 1:0.5 1:0.5 1:0.5 1:0.5 1:0.5 mol % 15 5 5 15 50 50 50   HO—R—OH CHDA (mol) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 approx. HO—R—OH 0.03 0.01 0.01 0.03 0.1 0.1 0.1 approx. TMCBD BDO CHDM DDD TMPD NPG DDD (mol) DPC (mol) 0.3 0.3 0.3 0.3 0.3 0.3 0.3 approx. ISB (mol) 0.17 0.19 0.19 0.17 0.1 0.1 0.1 approx. Eta rel 1.606 1.396 1.41 1.301 1.094 1.119  1.149 Glass 153 145 145 94 94 84 gel-like transition at room temperature temperature in ° C. The mol data in the second column of Table 1 are reported as “approx.”, since they were rounded to the second decimal place. The ratio 2.04:1.00 (diols to diacids) served as a basis.

[0124] Examples 1 to 12 according to the invention show that the process of the invention afforded the desired polyester carbonate in high viscosities provided the amounts of additional diol according to the invention are observed. It can be seen here that the addition of a further aliphatic diol, especially of branched diols, causes the molecular weight to rise significantly in relation to an example in which no further aliphatic diol is present (see comparative example 1). Better miscibility was observed at higher temperatures, which meant it was possible for a further increase in molecular weight to take place. When an excessive amount of additional diol is used (see comparative examples 2 to 4), the increase in molecular weight is markedly lower.

Example 13 According to the Invention: Reaction in Step (i) of the Process

[0125] A flask with a short-path separator was charged with 0.10 mol of cyclohexane-1,4-dicarboxylic acid, 0.02 mol of BEPD (10%), and 0.18 mol of isosorbide and also 0.3 mol of diphenyl carbonate and 100 ppm of DMAP (4-dimethylaminopyridine; based on the starting materials CHDA, BEPD, DPC, and ISB) and also 0.0763 ml of an aqueous solution of lithium hydroxide (100 g/l), corresponding to approx. 20 ppm Li. The mixture was freed of oxygen by evacuating and releasing the vacuum with nitrogen four times. The mixture was heated gradually to 190° C. During this operation, carbon dioxide was continuously evolved. A 3 mL sample was then taken and analyzed by MALDI-TOF-MS. To ensure that the batch continued to polymerize, the reaction was heated to 220° C. and the pressure then gradually reduced to <1 mbar. An increase in viscosity was observed.

[0126] The results of the analysis are summarized in Table 2. The respective masses correspond to the Li adduct M+Li*. Various peaks were identified in which not only the ISB but also the BEPD could have reacted. This is a clear indication that the isosorbide and the BEPD already react under the process conditions of process step (i). In Table 2, ISB denotes an isosorbide unit minus the two terminal OH groups (these are described separately), CHDA stands for cyclohexane (cyclohexanedicarboxylic acid minus the two carboxylic acid groups), and BEPD stands for 2-butyl-2-ethylpropane-1,3-diol minus the two OH groups.

TABLE-US-00002 TABLE 2 Peaks in the MALDI-TOF spectrum Possible structure 383 Da HO-ISB-ester-CHDA-ester-phenyl 397 Da HO-BEPD-ester-CHDA-ester-phenyl 512 Da HO-ISB-carbonate-ISB-carbonate-BEPD-OH 555 Da HO-ISB-carbonate-ISB-ester-CHDA-ester-phenyl 607 Da HO-ISB-carbonate-ISB-ester-CHDA-ester-ISB-OH 613 Da Phenyl-ester-CHDA-ester-ISB-ester-CHDA-ester-phenyl 627 Da Phenyl-ester-CHDA-ester-BEPD-ester-CHDA-ester-phenyl 665 Da HO-ISB-ester-CHDA-ester-ISB-ester-CHDA-ester-phenyl 679 Da Phenyl-ester-CHDA-ester-ISB-ester-CHDA-ester-BEPD-OH 727 Da HO-ISB-carbonate-ISB-carbonate-ISB-ester-CHDA-ester- phenyl 785 Da Phenyl-ester-CHDA-ester-ISB-ester-CHDA-ester-ISB- carbonate-phenyl 837 Da HO-ISB-carbonate-ISB-ester-CHDA-ester-ISB-ester-CHDA- ester-phenyl

[0127] These results suggest that the process of the invention leads to a polyester carbonate that differs from a polyester carbonate produced via a two-step process (i.e. production first of a diaryl dicarboxylate through reaction of a cycloaliphatic dicarboxylic acid with a diaryl carbonate and purification of said diaryl dicarboxylate, followed by condensation of the diaryl dicarboxylate with a diaryl carbonate and an aliphatic dihydroxy compound). It is highly likely that different statistical distributions of carbonate units and/or ester units are present in the different polyester carbonates.