Polyester Carbonates Consisting of Different Diols in a Defined Ratio

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 further aliphatic dihydroxy compound, to a polyester carbonate and to a molding compound and a molded product containing the polyester carbonate. The polyester carbonates according to the invention are characterized by good mechanical properties and molecular weights.

Claims

1. A polyestercarbonate, comprising the structural formula (1) ##STR00021## in which A independently per repeating unit represents at least either structural unit (A) or structural unit (B), where (A) represents chemical formula (2) ##STR00022##  and (B) represents chemical formula (3)
*—X—*  (3), where x represents a branched alkylene group having 4 to 20 carbon atoms, which may optionally be interrupted by at least one heteroatom, or a cycloalkylene group comprising at least one branch, wherein the cycloalkylene group has 4 to 20 carbon atoms, which may optionally be interrupted by at least one heteroatom, y each independently represents chemical formula (IIIa) or (IIIb) ##STR00023## in which B each independently represents a CH.sub.2 group or a heteroatom selected from the group consisting of O and S, R.sub.1 each independently represents a single bond or an alkylene group having 1 to 10 carbon atoms, n is a number between 0 and 3, and 0<x<1, where the * in each case indicate the position at which the chemical formulae are incorporated into the polyestercarbonate, wherein the polyestercarbonate comprises 98 mol % to 75 mol % of structural unit (A) and 2 mol % to 25 mol % of structural unit (B), based in each case on the sum of the structural units (A) and (B), and wherein the polyestercarbonate has a relative solution viscosity, measured in dichloromethane at a concentration of 5 g/l at 25° C. with an Ubbelohde viscometer, of 1.20 to 1.70.

2. The polyestercarbonate as claimed in claim 1, wherein the polyestercarbonate consists of structural formula (1) to an extent of at least 80% by weight based on the total weight of the polyestercarbonate.

3. The polyestercarbonate as claimed in claim 1, wherein the polyestercarbonate comprises the following repeating units (i) to (iv) in any order ##STR00024## in which a, b, c and d each independently represent a natural number which indicates the average number of repeating units in each case.

4. The polyestercarbonate as claimed in claim 1, wherein 1 mol % to 20 mol % of the polyestercarbonate consists of the structural motif *—X—O—*, based on the total sum of the following structural motifs ##STR00025##

5. The polyestercarbonate as claimed in claim 1, wherein *—X—* is selected from the group consisting of 2,2-bis(4-cyclohexylene)propane, 2-butyl-2-ethyl-1,3-propylene, 2,2,4,4-tetramethyl-1,3-cyclobutylene, 2,2,4-trimethyl-1,3-pentylene, 2,2-dimethylpropan-1,3-ylene, 8-(methylene)-3-tricyclo[5.2.1.02,6]decanyl]methylene and any desired mixtures thereof.

6. The polyestercarbonate as claimed in claim 1, wherein y is selected from the group consisting of 1,4-cyclohexylene, 1,3-cyclohexylene, 1,2-cyclohexylene, tetradihydro-2,5-furanylene, tetradihydro-2,5-dimethylfuranylene, decahydro-2,4-naphthalenylene, decahydro-2,5-naphthalenylene, decahydro-2,6-naphthalenylene and decahydro-2,7-naphthalenylene.

7. The polyestercarbonate as claimed in claim 1, wherein the molar ratio of the sum of the structural motifs ##STR00026## to the structural motif ##STR00027## is 6:4 to 9:1.

8. The polyestercarbonate as claimed in claim 1, wherein at least 45 mol of the polyestercarbonate consists of the structural motif ##STR00028## based on the total sum of the following structural motifs ##STR00029##

9. A molding compound comprising a polyestercarbonate as claimed in claim 1.

10. A molded article comprising a polyestercarbonate as claimed in a claim 1.

11. A process for preparing a polyestercarbonate as claimed in claim 1 by means of melt transesterification, comprising the steps of (i) reaction at least of at least one dicarboxylic acid of chemical formula (IIa) or (IIb) ##STR00030## in which B each independently represents a CH.sub.2 group or a heteroatom selected from the group consisting of O and S, R.sub.1 each independently represents a single bond or an alkylene group having 1 to 10 carbon atoms, and n is a number between 0 and 3, 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 of chemical formula (I)
HO—X—OH  (I), in which X represents a branched alkylene group having 4 to 20 carbon atoms, which may optionally be interrupted by at least one heteroatom, or a cycloalkylene group comprising at least one branch, wherein the cycloalkylene group has 4 to 20 carbon atoms, which may optionally be interrupted by at least one heteroatom, and (ii) further condensation of the mixture obtained from process step (i), 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), based in each case on the sum of components (A) and (B).

12. The process as claimed in claim 11, wherein the molar ratio of all aliphatic dihydroxy compounds present in process step (i) to all cycloaliphatic dicarboxylic acids present in process step (i) prior to the reaction in process step (i) is 1:0.6 to 1:0.05.

13. The process as claimed in claim 11, wherein the at least one further aliphatic dihydroxy compound of chemical formula (I) is selected from the group consisting of 2,2-bis(4-hydroxycyclohexyl)propane, 2-butyl-2-ethyl-1,3-propanediol, 2-(2-hydroxyethoxy)ethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,2-dimethylpropane-1,3-diol, 8-(hydroxymethyl)-3-tricyclo[5.2.1.02,6]decanyl]methanol and any desired mixtures thereof.

14. The process as claimed in claim 11, wherein the at least one cycloaliphatic dicarboxylic acid is selected from the group consisting of 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, tetradihydro-2,5-furandicarboxylic acid, tetradihydro-2,5-dimethylfurandicarboxylic acid, decahydro-2,4-naphthalenedicarboxylic acid, decahydro-2,5-naphthalenedicarboxylic acid, decahydro-2,6-naphthalenedicarboxylic acid and decahydro-2,7-naphthalenedicarboxylic acid.

15. The process as claimed in claim 11, wherein the at least one diaryl carbonate is selected from the group consisting of a compound of formula (2) ##STR00031## 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.

16. The polyestercarbonate as claimed in claim 1, wherein the cycloalkylene group contains a plurality of rings.

17. The polyestercarbonate as claimed in claim 1, wherein: B each independently represents a CH.sub.2 group or an oxygen atom, R.sub.1 each independently represents a single bond, and n is 0 or 1.

18. The process as claimed in claim 11, wherein the cycloalkylene group contains a plurality of rings.

19. The process as claimed in claim 11, wherein: B each independently represents a CH.sub.2 group or an oxygen atom, R.sub.1 each independently represents a single bond, and n is 0 or 1.

Description

EXAMPLES

Materials Used:

[0138] Cyclohexanedicarboxylic acid: 1,4-Cyclohexanedicarboxylic acid; CAS 1076-97-7 99%; Tokyo Chemical Industries, Japan, abbreviated as CHDA. The CHDA contained less than 1 ppm sodium per elemental analysis

[0139] Diphenyl carbonate: Diphenyl carbonate, 99.5%, CAS 102-09-0; Acros Organics, Geel, Belgium, abbreviated as DPC

[0140] 4-Dimethylaminopyridine: 4-dimethylaminopyridine; >98.0%; purum; CAS 1122-58-3; Sigma-Aldrich, Munich, Germany, abbreviated as DMAP

[0141] Isosorbide: isosorbide (CAS: 652-67-5), 99.8%, Polysorb PS A; Roquette Freres (62136 Lestrem, France); abbreviated as ISB

[0142] Lithium hydroxide monohydrate (CAS: 1310-66-3); >99.0%; Sigma-Aldrich

[0143] 2-Butyl-2-ethyl-1,3-propanediol: CAS No.: 115-84-4; Aldrich (abbreviated as BEPD)

[0144] 2,2,4,4-Tetramethyl-1,3-cyclobutanediol: 98% (CAS: 3010-96-6); ABCR (abbreviated as TMCBD)

[0145] 2,2,4-Trimethyl-1,3-pentanediol; CAS No.: 144-19-4; Aldrich (abbreviated as TMPD)

[0146] Neopentyl glycol (2,2-dimethylpropane-1,3-diol); CAS: 126-30-7; Aldrich (abbreviated as NPG)

[0147] 1,4-Butanediol: CAS: 110-63-4; Merck 99%; (abbreviated as BDO)

[0148] 1,4-Cyclohexanedimethanol: CAS: 105-08-8, Aldrich 99% (abbreviated as CHDM)

[0149] 1,12-Dodecanediol: CAS: 5675-51-4, Aldrich 99% (abbreviated as DDD)

Analytical Methods:

Solution Viscosity

[0150] 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. with an Ubbelohde viscometer. The determination was carried out in accordance with DIN 51562-3; 1985-05. This method involves measuring the flow times of the polyestercarbonate to be measured through the Ubbelohde viscometer in order to then ascertain the difference in viscosity between the polymer solution and its solvent. For this purpose, the Ubbelohde viscometer is first calibrated by measuring the pure solvents dichloromethane, trichloroethylene and tetrachloroethylene (always performing at least 3 measurements, but at most 9 measurements). This is followed by the calibration proper using the solvent dichloromethane. The polymer sample is then weighed out, dissolved in dichloromethane and then the flow time is determined three times for this solution. The mean value for the flow times is corrected via the Hagenbach correction and the relative solution viscosity is calculated. Determination of the glass transition temperature

[0151] 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. Tensile tests

[0152] The product was dissolved in dichloromethane and neutralized with approx. 50 mg of phosphonic acid (in aq.). After homogenization, the dichloromethane was evaporated off under ambient air and the remainder was removed at approximately 60° C. in a vacuum drying cabinet under the best possible vacuum. A hand lever machine and a Retsch mill with a sieve size of 1.5 mm were used for the following mechanical comminution. The pre-drying at 70° C. and <50 mbar in the vacuum drying cabinet was carried out for approx. 16 h. The temperature was then raised to 110° C. and drying continued for 5 h.

[0153] For the tensile tests, the films produced in the melt press were cut into 5-mm-wide strips having a length of at least 50 mm. The tensile testing was conducted in accordance with the ASTM D 638 standard. The strips were drawn at a room temperature of approx. 25° C. and a relative humidity of approx. 20%. The tensile modulus was ascertained with a pretension of 0.01 MPa with a test speed of 100 mm/min. The test speed for the continuous measurement was 50 mm/min. The switch-over of the elongation rate from 100 mm/min to 50 mm/min was position-controlled via the crosshead displacement. The clamping length was 20 mm. No clamp failure was observed. The results of the tensile tests as summarized as average values from in each case five individual measurements.

[0154] The flow behavior is ascertained by determining the melt viscosity using a plate-plate viscometer in accordance with ISO 6721-10 from 1999. The value of the viscosity at 1 hertz and at 10 hertz is used in this case:

[0155] The melt viscosities were determined using an Ares G-2 rotational rheometer from TA Instruments (New Castle, Del. 19720, USA). A plate-plate geometry was used (25 mm diameter). The plate diameter amounts to 25 mm (PP25). The samples, where evaporation residues were involved, were first dried in a vacuum drying cabinet at approx. 80° C. and then pressed into thin films using a hot press at 240° C. The samples were measured at various temperatures above the glass transition temperature. The deformation during the measurement was chosen so that measurement was conducted within the linear-elastic range. The measurement results at the various temperatures were subsequently shifted to a master curve at the reference temperature 200° C. using time-temperature superposition.

Comparative Example 1 (Experiment without Additional Diol)

[0156] A flask with a short-path separator was initially charged with 17.20 g (0.10 mol) of 1,4-cyclohexanedicarboxylic acid and 29.83 g (0.204 mol) of isosorbide, and also 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 μl of an aqueous solution of lithium hydroxide (100 g/l), corresponding to approx. 30 ppm Li. The mixture was freed of oxygen by evacuating and venting with nitrogen four times. The mixture was melted and heated to 160° C. at standard pressure with stirring. The mixture was stirred for 40 minutes at 160°, for 60 minutes at 175° C., for 30 minutes at 190° C. for 10 minutes at 205° C. 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 vacuum was applied. The pressure was lowered to 10 mbar within 30 minutes. Phenol was continuously removed in the process. 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 was continued for a further 10 minutes. Processing of the mixture was then stopped.

[0157] A light yellow polymer having a solution viscosity of eta rel 1.33 was obtained.

[0158] 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 respectively specified in table 1 were in addition initially charged in the flask with a short-path separator, together with all the other polymer-forming monomers 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 CHDA/ISB/ 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 HO—R—OH molar ratio mol % 0 5 10 15 5 15 10 5 5 HO—R—OH CHDA 0.1 0.2 0.2 0.2 0.2 0.2 0.1 0.1 0.1 (mol) approx. HO—R—OH 0 0.02 TMPD 0.04 TMPD 0.06 TMPD 0.02 NPG 0.06 NPG 0.02 BEPD 0.01 BEPD 0.01 TMCBD approx. (mol) DPC 0.3 0.6 0.6 0.6 0.6 0.6 0.3 0.3 0.3 (mol) approx. ISB 0.2 0.38 0.36 0.34 0.38 0.34 0.18 0.19 0.19 (mol) 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. Tensile 1740 ± 128  283 ± 64  1130 ± 183  1020 ± 55.8  1210 ± 110 917 ± 145 79.6 ± 29.3 modulus (modulus of elasticity) N/mm.sup.2 Elongation at 8.8 ± 0.9 8.3 ± 2.8 7.6 ± 1.5 16.7 ± 13.5 10.0 ± 1.5 8.5 ± 2.4 6.2 ± 1.2 break (DR) % Shear 27840 35920 viscosity Pa s Pa s at 1 Hz Shear 8160 7760 viscosity Pa s Pa s at 10 Hz Inv. Comp. Comp. Comp. Comp. Comp. Comp. 9 2 3 4 5 6 7 CHDA/ISB/ 33/57/10 33/64/3 33/64/3 33/57/10 33/335/33.5 33/33.5/33.5 33/33.5/33.5 HO—R—OH molar ratio mol % 15 5 5 15 50 50 50 HO—R—OH CHDA 0.1 0.1 0.1 0.1 0.1 0.1 0.1 (mol) approx. HO—R—OH 0.03 TMCBD 0.01 BDO 0.01 CHDM 0.03 DDD 0.1 TMPD 0.1 NPG 0.1 DDD approx. (mol) DPC 0.3 0.3 0.3 0.3 0.3 0.3 0.3 (mol) approx. ISB 0.17 0.19 0.19 0.17 0.1 0.1 0.1 (mol) approx. Eta rel 1.606 1.396 1.41 1.31 1.094 1.119 1.149 Glass 153 145 145 94 94 84 gel-like transition at room temperature in temperature ° C. Tensile  135 ± 75.4 83.5 ± 7   258 ± 128 998 ± 88  Not Not Not modulus measurable measurable measurable (modulus of elasticity) N/mm.sup.2 Elongation at 5.7 ± 1.7 10.2 ± 3.6 7.0 ± 0.8 7.7 ± 0.6 Not Not Not break measurable measurable measurable (DR) % Shear 60960 Pa s viscosity at 1 Hz Shear 15470 Pa s viscosity at 10 Hz The mol data in the first 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) was used as a basis.

[0159] Examples 1 to 9 according to the invention show that the process of the invention affords the desired polyestercarbonates in high viscosities provided that the amounts of additional diol according to the invention are observed. It can be seen here that the addition of a further aliphatic, branched diol causes the molecular weight to rise significantly compared 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 5 to 7), the increase in molecular weight is markedly lower. In addition, it can be seen that the presence of a structural unit (B) in the polyestercarbonate initially lowers the mechanical properties such as the modulus of elasticity and the elongation at break, but a higher molecular weight can be achieved overall. The higher the proportion of structural units (B), the better the mechanical properties such as the modulus of elasticity and elongation at break. However, an excessive proportion of structural unit (B) in turn leads to a low molecular weight and hence again to a deterioration in the mechanical properties. A good balance between mechanical properties and molecular weight is therefore achieved in the amount range of structural unit (B) according to the invention. In addition, high molecular weights lead to lower end group contents. This is advantageous in principle since a reduction in the molecular weight usually starts from the chain end.

[0160] It should be noted that the error values for the modulus of elasticity and the elongation at break are relatively high. This results from the fact that relatively small sample amounts were used and in some cases there was the formation of bubbles. However, a person skilled in the art understands that the resulting values are significant despite these errors.

[0161] It can likewise be seen that the use of additional diols comprising branches (both branched alkylene groups and branched cycloalkylene groups) results in a lower shear viscosity despite a higher solution viscosity and with comparable Tg values.