HK1050699A - Production and use of polyester carbonates - Google Patents

Description

Preparation and use of polyester carbonates

Technical Field

The present application relates to polyester carbonates (polyester carbonates) and more particularly to a melt transesterification process for the preparation of polyester carbonates.

Background

The preparation of polyester carbonates by the interfacial process from difunctional aliphatic carboxylic acids and dihydroxy compounds has been described, for example, in EP-A433716, U.S. Pat. No. 4,983,706 and U.S. Pat. No. 5,274,068. However, as disclosed in EP-A433716, the addition of large amounts of the known carboxylic acids for the preparation of polyestercarbonates can only be carried out in the interfacial process by complicated and expensive processes.

The addition of aromatic or aliphatic dicarboxylic acids by the so-called pyridine process is described in U.S. Pat. No. 3,169,121.

Transesterification processes are well known for the addition of aromatic dicarboxylic acids, as disclosed, for example, in U.S. Pat. No. 4,459,384. The addition of aliphatic dicarboxylic acids is disclosed in JP-A2000248057, in which all monomers are added together at the start of the reaction and heated and/or condensed together, as is customary.

Also, JP-A3203926 describes a transesterification method with the addition of an aliphatic dicarboxylic acid. In this process, a dicarboxylic acid is reacted with an aromatic dihydroxy compound and a bicarbonate salt, and an alkali metal or alkaline earth metal compound is used as a catalyst. Apart from the proportions in which the dicarboxylic acids are added, this document gives no more detailed information about side reactions which may occur or the intrinsic color of the resulting polymers.

The polyester carbonates prepared by the interfacial process have good intrinsic color, but contain small amounts of anhydrides of the dicarboxylic acids used, even of the free acids, which are undesirable, see EP-A926177. However, the aim of the interfacial process is in principle to incorporate the dicarboxylic acids as completely as possible into the polyestercarbonates so that the product has as many ester bonds as possible and as few acid or anhydride structures as possible, since the latter impair the stability of the polyestercarbonates.

In contrast, polyestercarbonates synthesized by the transesterification process, although containing little anhydride structure, generally have a very deep inherent color, which in turn makes them as little useful as possible for most applications.

Disclosure of Invention

The object of the present invention was therefore to prepare polyestercarbonates which contain as many ester bonds as possible and as few acid or anhydride structures as possible on the one hand and which have good intrinsic color on the other hand.

A transesterification process for preparing polyesters is disclosed. In a first stage of the process, a first mixture comprising at least one dihydroxy compound and at least one diaryl carbonate is heated in an inert atmosphere to form a low condensate. In a second stage, at least one dicarboxylic acid is added to the low condensate to form a second mixture. The second mixture is heated to a temperature of not greater than 290 ℃ in the presence of a quaternary onium compound as a catalyst to form a polyestercarbonate. The hydroxyaryl compound (hydroxyyaryl) formed during the entire course of the process is removed by distillation under reduced pressure.

Detailed Description

The above objects are surprisingly achieved with the transesterification process of the present invention.

The present application therefore provides a process for preparing polyestercarbonates by transesterification of diaryl carbonates with dihydroxy compounds and dicarboxylic acids, characterized in that the polycondensation is carried out in the presence of a quaternary onium compound as catalyst and the dicarboxylic acid is added only after the low polycondensation of the dihydroxy compounds, the temperature not exceeding 290 ℃.

The present application furthermore provides the polyestercarbonates obtainable by the process according to the invention themselves.

According to the process of the present invention, in the first stage, the mixture of dihydroxy compound and diaryl carbonate is heated under reduced pressure in an inert atmosphere for 30 to 300 minutes, preferably 60 to 150 minutes, up to 200-290 ℃, preferably 230-290 ℃, particularly preferably 250-280 ℃ and the hydroxyaryl compound component formed is distilled off. The dicarboxylic acid or mixture of dicarboxylic acids is then added in the second stage and the reaction mixture is heated at a temperature of not more than 290 ℃ for about 60 to 200 minutes, preferably 90 to 180 minutes, to form the polyestercarbonate by polycondensation. At each stage, the pressure is chosen so that the hydroxyaryl compound component can be distilled off without problems.

The polyester carbonates obtained according to the invention are light in color, i.e.have a color number of < 0.2, and contain particularly small amounts of free dicarboxylic acids or anhydride structures, and therefore satisfy the following formula:

in the formula (I), the compound is shown in the specification,

q is a characteristic value of the light-emitting element,

x is the weight percent of esterified acid in the polyestercarbonate,

y is the weight% of free COOH in the polyestercarbonate,

z is the amount of anhydride structural units in the polyestercarbonate in weight%.

Suitable dicarboxylic acids for use in the process of the present invention are compounds of the following formula (I):

HOOC-T-COOH (I)

in the formula (I), the compound is shown in the specification,

t represents a linear or branched, saturated or unsaturated alkyl, aralkyl or cycloalkyl group having 8 to 40 carbon atoms.

Preferred are saturated linear alkyl diacids having 8 to 40 carbon atoms, and particularly preferred are diacids having 12 to 36 carbon atoms. Of these types of substances, fatty acids, in particular hydrogenated dimeric fatty acids, are particularly suitable.

Examples of dicarboxylic acids of the formula (I) or of mixtures of these fatty acids are: sebacic acid, dodecanedioic acid, stearic acid, palmitic acid, hydrogenated dimeric fatty acids (e.g. Pripol 1009 from Uniqema).

Pripol 1009 from Uniqema is a mixture of hydrogenated dimer fatty acids, the composition of which is known from the details provided by Uniqema to be roughly as follows:

particularly preferred are dodecanedioic acid and Pripol 1009.

Pripol 1009 is preferable.

One kind of dicarboxylic acid represented by the formula (I) may be used, or a combination of a plurality of kinds of dicarboxylic acids represented by the formula (I) may be used.

The dicarboxylic acids used, as well as the other starting materials used, should of course be as pure as possible. However, the purity of commercially available products often varies widely. In particular fatty acids or hydrogenated dimeric fatty acids, will contain considerable amounts of by-products formed in the preparation of these fatty acids.

In the process of the invention, the molar ratio between the amounts of dicarboxylic acid and dihydroxy compound used is X: 1, with 0 < X < 10, preferably 0.01 < X < 1, particularly preferably 0.02 < X < 0.5, most preferably 0.08 < X < 0.2.

The general or preferred definitions and/or explanations of radicals, parameters above or below can also be combined with one another in any desired manner, i.e. between the respective ranges and preferred ranges. The details apply appropriately to the end products, precursors, intermediates, preparation processes and process steps.

Dihydroxy compounds suitable for use in the process of the present invention are compounds of formula (II):

HO-Ar-OH (II) wherein Ar is an aromatic radical having 6 to 30 carbon atoms, preferably having 6 to 25 carbon atoms, which may contain one or more aromatic rings, may be substituted, may contain aliphatic or alicyclic groups or alkaryl groups or heteroatoms as bridging moieties.

Examples of dihydroxy compounds of formula (II) are: hydroquinone, resorcinol, dihydroxydiphenyl, bis (hydroxyphenyl) alkane, bis (hydroxyphenyl) cycloalkane, bis (hydroxyphenyl) sulfide, bis (hydroxyphenyl) ether, bis (hydroxyphenyl) ketone, bis (hydroxyphenyl) sulfone, bis (hydroxyphenyl) sulfoxide, α' -bis (hydroxyphenyl) diisopropylbenzene, and ring-alkylated and ring-halogenated compounds thereof.

These compounds and other suitable diphenols are described, for example, in U.S. Pat. Nos. 3,028,365, 3,148,172, 3,275,601, 2,991,273, 3,271,367, 3,062,781, 2,970,131 and 2,999,846, DE-A1570703, 2063050, 2063052, 22110956, FR-B1561518 and the monograph "H.Schnell, Chemistry and Physics of Polycarbonates, Interscience publishers, New York 1964".

Preferred dihydroxy compounds are, for example: 4,4 ' -dihydroxydiphenyl, 2-bis (4-hydroxyphenyl) propane, 2, 4-bis (4-hydroxyphenyl) -2-methylbutane, 1-bis (4-hydroxyphenyl) cyclohexane, 1-bis (4-hydroxyphenyl) -4-methylcyclohexane, α ' -bis (4-hydroxyphenyl) -p-diisopropylbenzene, α ' -bis (4-hydroxyphenyl) -m-diisopropylbenzene, bis- (4-hydroxyphenyl) sulfone, bis- (4-hydroxyphenyl) methane, 1-bis (4-hydroxyphenyl) -3, 3, 5-trimethylcyclohexane, bis- (2, 6-dimethyl-4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) hexafluoropropane, (4-hydroxyphenyl) -1-phenylethane, (4-hydroxyphenyl) diphenylmethane, dihydroxydiphenyl ether, 4 '-dithiol, bis (4-hydroxyphenyl) -1- (1-naphthyl) ethane, bis (4-hydroxyphenyl) -1- (2-naphthyl) ethane, dihydroxy-3- (4-hydroxyphenyl) -1, 1, 3-trimethyl-1H-indene-5-ol, dihydroxy-1- (4-hydroxyphenyl) -1, 1, 3-trimethyl-1H-indene-5-ol, 2', 3, 3 '-tetrahydro-3, 3, 3', 3 ' -tetramethyl-1, 1 ' -spirobi [ 1H-indene ] -5, 5 ' -diol.

Particularly preferred are: resorcinol, bis (4-hydroxyphenyl) -1- (1-naphthyl) ethane, bis (4-hydroxyphenyl) -1- (2-naphthyl) ethane, 2-bis (4-hydroxyphenyl) propane, α '-bis (4-hydroxyphenyl) p-diisopropylbenzene, α' -bis (4-hydroxyphenyl) m-diisopropylbenzene, 1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) -3, 3, 5-trimethylcyclohexane, bis (4-hydroxyphenyl) diphenylmethane.

The best is that: bis (4-hydroxyphenyl) -3, 5, 5-trimethylcyclohexane, 4' -dihydroxybiphenyl, 2-bis (4-hydroxyphenyl) propane.

Most preferred is bis (4-hydroxyphenyl) -3, 3, 5-trimethylcyclohexane.

One diphenol of the formula (II) may be used, as may combinations of diphenols of the formula (II).

The diaryl carbonates of the present invention are diesters of carbonic acid of the formulae (III) and (IV):in the formulaR, R 'and R' are independent of each other and represent H, optionally branched C₁-C₃₄Alkyl/cycloalkyl, C_7-34Alkylaryl or C₆-C₃₄Aryl groups, for example: diphenyl carbonate, butylphenyl-phenyl carbonate, di (butylphenyl) carbonate, isobutylphenyl-phenyl carbonate, di (isobutylphenyl) carbonate, tert-butylphenyl-phenyl carbonate, di (tert-butylphenyl) carbonate, n-pentylphenyl-phenyl carbonate, di (n-pentylphenyl) carbonate, n-hexylphenyl-phenyl carbonate, di (n-hexylphenyl) carbonate, cyclohexylphenyl-phenyl carbonate, di (cyclohexylphenyl) carbonate, phenylphenol-phenyl carbonate, di (phenylphenol) carbonate, isooctylphenyl-phenyl carbonate, di (isooctylphenyl) carbonate, n-nonylphenyl-phenyl carbonate, di (n-nonylphenyl) carbonate, cumylphenyl-phenyl carbonate, di (phenylphenol) carbonate, di (phenylphenol carbonate), di (octylphenyl) carbonate, n-nonylphenyl-phenyl carbonate, di (n-nonylphenyl) carbonate, cumylphenyl-phenyl carbonate, Bis (cumylphenyl) carbonate, naphthylphenyl-phenyl carbonate, bis (naphthylphenyl) carbonate, di-t-butylphenyl-phenyl carbonate, bis (di-t-butylphenyl) carbonate, dicumylphenyl-phenyl carbonate, bis (dicumylphenyl) carbonate, 4-phenoxyphenyl-phenyl carbonate, bis (4-phenoxyphenyl) carbonate, 3-pentadecylphenyl-phenyl carbonate, bis (3-pentadecylphenyl) carbonate, tritylphenyl-phenyl carbonate, bis (tritylphenyl) carbonate, preferably diphenyl carbonate, t-butylphenyl-phenyl carbonate, bis (t-butylphenyl) carbonate, phenylphenol-phenyl carbonate, bis (phenylphenol) carbonate, cumylphenyl-phenyl carbonate, di (naphthylphenyl) carbonate, di (tert-butylphenyl) carbonate, di (4-phenoxyphenyl) carbonate, 3-pentadecylphenyl-phenyl carbonate, di (3-pentadecylphenyl) carbonate, tritylphenyl-phenyl carbonate, bis (, Bis (cumylphenyl) carbonate, particularly preferably diphenyl carbonate.

Furthermore, the phenolic compounds used as carbonates can also be used directly as hydroxyaryl compounds added to one of the above-mentioned carbonates, for influencing the end groups of the polyester carbonate. Preferred mixtures are those containing diphenyl carbonate. According to the process of the invention, the hydroxyaryl compound or the hydroxyaryl-containing compound may be added to the reaction mixture at any time, preferably at the beginning of the reaction, the addition being carried out in portions. The proportion of the free hydroxyaryl compound may be 0.4 to 17 mol%, preferably 1.3 to 8.6 mol% (referred to as dihydroxy compound). In this regard, the hydroxyaryl compound or hydroxyaryl-containing compound may be added prior to the reaction, as well as during all or part of the reaction.

The carbonic acid diester is used in a ratio of 1: 0.9 to 1: 1.3, preferably 1: 1.0 to 1: 1.2, particularly preferably 1: 1.0 to 1: 1.1, relative to the total amount of dihydroxy compound and dicarboxylic acid. Mixtures of the above-mentioned carbonic diesters or dicarboxylic acids can also be used.

An ammonium compound or a phosphonium compound can be used as the catalyst for the synthesis, and the amount thereof is preferably 0.0001 to 0.5 mol%, particularly preferably 0.001 to 0.2 mol%, based on the total amount of the dicarboxylic acid and the dihydroxy compound.

Phosphonium salts may optionally be used in combination with other suitable catalysts which do not lead to more deep-set coloration, as catalysts for the preparation of the polyester carbonates according to the invention.

The phosphonium salts of the present invention are compounds of formula (V):in the formula, R^1-4May represent the same or different C₁-C₁₀Alkyl radical, C₆-C₁₀Aryl radical, C₇-C₁₀Aralkyl or C₅-C₆Cycloalkyl, preferably methyl or C₆-C₁₄Aryl, especially preferably methyl or phenyl, X^-Can be an anion, such as hydroxide, sulfate, bisulfate, bicarbonate, carbonate, halide (preferably chloride), OR an alkoxide of the formula OR, wherein R can be C₆-C₁₄Aryl or C₇-C₁₂Aralkyl, preferably phenyl.

Preferred catalysts are tetraphenylphosphonium chloride, tetraphenylphosphonium hydroxide, tetraphenylphosphonium phenoxide, particularly preferably tetraphenylphosphonium phenoxide.

The polyester carbonates may be intentionally branched and may therefore contain small amounts of branching agents, in the range of 0.02 to 3.6 mol%, based on the total amount of dicarboxylic acid and dihydroxy compound. Suitable branching agents are those compounds which are suitable for the preparation of polycarbonates and which contain three or more functional groups, preferably compounds having three or more than three phenolic OH groups, for example 1, 1, 1-tris (4-hydroxyphenyl) ethane and isatin bisphenol.

Auxiliary substances and reinforcing agents may be added to the polyester carbonates according to the invention to modify the properties. Known substances and agents include heat and UV stabilizers, flow aids, mold release agents, flameproofing agents, pigments, finely divided minerals, fibrous substances, for example alkyl and aryl phosphites, phosphoric acid, phosphonic acid, low molecular weight carboxylic esters, halogen compounds, salts, chalk, quartz powder, glass and carbon fibers, pigments and mixtures thereof. These compounds are described, for example, in WO99/55772, pages 15-25, and "Plastics Additives", R.G Graprofile and H.M muller, Hanser Publishers 1983.

In addition, other polymers, such as polyolefins, polyurethanes, polyesters, acrylonitrile/butadiene/styrene, and polystyrene, may also be added to the polyestercarbonates of the invention.

These substances are preferably added to the polyester carbonates prepared in conventional equipment, but may also be added at another stage of the preparation process, if desired.

The polyester carbonates obtainable by the process of the invention can be processed in customary machines, such as extruders or injection molding machines, by customary means into any desired molded articles, for example into films or sheets.

In addition to the use of the polyester carbonates according to the invention and/or corresponding molding compositions for the production of molded parts and extrudates, the present invention provides, in particular, optical articles, sheets and films and/or corresponding molded articles, preferably optical articles, made from the polyester carbonates according to the invention.

Examples of such uses include, but are not limited to, the following:

1. safety panels, known to be required in many areas of construction, vehicles and aircraft, and helmet shields.

2. Extruded and solution sheets are manufactured for displays or motors, and for ski sheets.

3. Transparent panels, in particular hollow chamber panels (hollow chamber panels), are manufactured, for example, for covering buildings such as stations, greenhouses and lighting installations.

4. To make a traffic signal cover or pavement marker.

5. As translucent plastics containing glass fibers, use can optionally be made of light technology (see, for example, DE-OS 1554020).

6. For the manufacture of precision injection molded parts.

7. Optical applications, such as optical storage media (CD, DVD, MD), goggles or lenses for cameras and film cameras (see, for example, DE-OS 2701173).

8. For use with a jack housing and a plug-type connector.

9. As a carrier material for organic photoconductors.

10. For the manufacture of lighting devices, such as vehicle headlamps, diffuse lighting panels or lamp housings.

11. For medical use, e.g. oxygenators, dialysers.

12. For food use.

13. For automotive parts.

14. For use in sports articles.

15. For household articles such as sink and letter box housings.

16. Housings for, for example, electrical panels, appliances, household goods.

17. Structural components of household goods, electrical appliances and electronic devices.

18. For the manufacture of motorcycle helmets and protective helmets.

19. For various applications, such as barn feeding doors or animal cages.

The polyester carbonates according to the invention are most particularly suitable for the production of optical and magneto-optical articles, in particular data storage media, such as CDs, DVDs, MDs and derivatives thereof, i.e. writable and rewritable data carriers, such as CD-ROMs, CD-R, CD-RWs, DVD-ROMs, HD-DVDs, etc.

The following describes embodiments of the present invention.

The relative solution viscosity was measured at 25 ℃ in dichloromethane at a concentration of 5 g/l.

The phenolic OH content was obtained by IR measurement. For this purpose, a solution of 2 g of polymer in 50 ml of methylene chloride is measured differentially at 3582cm in comparison with pure methylene chloride^-1The extinction difference is determined.

The content of esterified acids in polyestercarbonates (x) was measured in% by weight with a solution of 1 g of polyestercarbonate in 100 ml of methylene chloride. For this purpose, the IR spectrum of the solution was recorded and measured according to the PLS method. The spectral range for PLS determination was 1919-1581cm^-1And 2739-2894cm^-1. Calibration was performed with 29 samples of known composition.

Likewise, the content (y) of free carboxylic acid groups in the polyestercarbonates was determined by IR spectroscopy on the above solutions. The spectra of methylene chloride, water vapor and acid-free and anhydride-free polyester carbonate with 20% by weight of Pripol were subtracted at 1709cm^-1The extinction difference was measured. The measurements were calibrated for polyester carbonates of different Pripol contents. Values < 0.01 are zero.

The measurement of the anhydride structure (z) was carried out on the basis of the IR spectrum described above: find 1816cm^-1Extinction of position minus 1860cm^-1Extinction at (b) and a value of base value (contribution) of 0.031. The method does not perform calibration.

The difference in extinction at 420nm and 700nm, measured in dichloromethane at a concentration of 2.4 g/50 ml, at a layer thickness of 10 cm, is defined as the colour number.

Example 1

53.94 g (0.174 mol) of bisphenol TMC, 45.41 g (0.212 mol) of diphenyl carbonate and 0.0494 g (8X 10 mol) were weighed out^-5Moles) phenolated tetraphenylphosphonium (measured as mixed crystals with 30% by weight of phenol based on the mixed crystals) which were charged to a 500 ml three-neck flask equipped with a stirrer, an internal thermometer and a Vigreux column with bridge (30 cm, mirror coating). The apparatus was evacuated and purged with nitrogen (three times) to exclude atmospheric oxygen, and the mixture was melted at 150 ℃ and 100 mbar. The temperature was raised to 190 ℃ and the phenol formed was distilled off for 30 minutes. The temperature was now raised to 235 ℃ and after 15 minutes the vacuum was adjusted to 60 mbar and after a further 15 minutes the temperature was adjusted to 250 ℃. After a further 15 minutes the temperature was raised to 280 ℃ and 14.63 g (0.026 mol) of Pripol 1009 were added and the mixture was stirred for 1 hour. The vacuum was then reduced to 0.5 mbar and the mixture was stirred for a further 120 minutes. The results are summarized in table 1.

Example 2

1078.80 g (3.48 mol) of bisphenol TMC, 891.16 g (4.16 mol) of diphenyl carbonate and 0.9874 g (1.6X 10 g) were weighed out^-3Moles) phenoltetraphenylphosphonium (as mixed crystals having 30% by weight of phenol based on the mixed crystals) were charged to a vessel with a stirrer. The vessel was evacuated and purged with nitrogen (three times) to exclude atmospheric oxygen, and the mixture was melted at 150 ℃ and 100 mbar. The temperature was raised to 190 ℃ and the phenol formed was distilled off for 60 minutes. The temperature was now raised to 235 ℃ and after 15 minutes the vacuum was adjusted to 60 mbar and after a further 15 minutes the temperature was adjusted to 250 ℃. After a further 15 minutes the temperature was raised to 280 ℃ and 292.50 g (0.52 mol) of Pripol 1009 were added and the mixture was stirred for 1 hour. The vacuum was then reduced to 0.5 mbar and the mixture was stirred for a further 75 minutes. KnotThe results are summarized in table 1.

Example 3

1078.80 g (3.48 mol) of bisphenol TMC, 891.16 g (4.16 mol) of diphenyl carbonate and 0.2469 g (4X 10 g) were weighed out^-4Moles) phenoltetraphenylphosphonium (as mixed crystals having 30% by weight of phenol based on the mixed crystals) were charged to a vessel with a stirrer. The vessel was evacuated and purged with nitrogen (three times) to exclude atmospheric oxygen, and the mixture was melted at 150 ℃. The temperature was raised to 190 ℃ and the phenol formed was distilled off for 60 minutes. The temperature was now raised to 235 ℃ and after 15 minutes the vacuum was adjusted to 60 mbar and after a further 15 minutes the temperature was adjusted to 250 ℃. After a further 15 minutes the temperature was raised to 280 ℃ and 292.50 g (0.52 mol) of Pripol 1009 were added and the mixture was stirred for 1 hour. The vacuum was then reduced to 0.5 mbar and the mixture was stirred for a further 120 minutes. The results are summarized in table 1.

Example 4

53.94 g (0.174 mol) of bisphenol TMC, 45.84 g (0.214 mol) of diphenyl carbonate and 0.0494 g (8X 10 mol) were weighed out^-5Moles) phenolated tetraphenylphosphonium (measured as mixed crystals with 30% by weight of phenol based on the mixed crystals) which were charged to a 500 ml three-neck flask equipped with a stirrer, an internal thermometer and a Vigreux column with bridge (30 cm, mirror coating). The apparatus was evacuated and purged with nitrogen (three times) to exclude atmospheric oxygen, and the mixture was melted at 150 ℃ and 100 mbar. The temperature was raised to 190 ℃ and the phenol formed was distilled off for 30 minutes. The temperature was now raised to 235 ℃ and after 15 minutes the vacuum was adjusted to 60 mbar and after a further 15 minutes the temperature was adjusted to 250 ℃. After a further 15 minutes the temperature was raised to 280 ℃ and 5.99 g (0.026 mol) of dodecanedioic acid were added and the mixture was stirred for 1 hour. The vacuum was then reduced to 0.5 mbar and the mixture was stirred for a further 60 minutes. The results are summarized in table 1.

Example 5

41.094 g (0.180 mol) of bisphenol A, 44.99 g (0.210 mol) of diphenyl carbonate and 0.0049 g (8X 10 g) were weighed out^-6Moles) phenolated tetraphenylphosphonium (measured as mixed crystals with 30% by weight of phenol based on the mixed crystals) which were charged to a 500 ml three-neck flask equipped with a stirrer, an internal thermometer and a Vigreux column with bridge (30 cm, mirror coating). The apparatus was evacuated and purged with nitrogen (three times) to exclude atmospheric oxygen, and the mixture was melted at 150 ℃. The temperature was raised to 190 ℃ and the mixture was stirred for 30 minutes. The phenol formed was distilled off at 100 mbar for 20 minutes. The temperature was now raised to 235 ℃ and after 15 minutes the vacuum was adjusted to 60 mbar and after a further 15 minutes the temperature was adjusted to 250 ℃. After a further 15 minutes, 4.61 g (0.02 mol) of dodecanedioic acid are added. After 15 minutes at 60 mbar the vacuum was adjusted to 5 mbar and after 30 minutes it was increased to high vacuum. After a further 15 minutes, the temperature was raised to 260 ℃ and the mixture was stirred for 30 minutes. The results are summarized in table 1.

Comparative example 1

1078.80 g (3.48 mol) of bisphenol TMC, 908.29 g (4.24 mol) of diphenyl carbonate and 0.9874 g (1.6X 10 g) were weighed out^-3Moles) phenoltetraphenylphosphonium (as mixed crystals having 30% by weight of phenol based on the mixed crystals) were charged to a vessel with a stirrer. The vessel was evacuated and purged with nitrogen (three times) to exclude atmospheric oxygen, and the mixture was melted at 150 ℃ and 100 mbar. The temperature was raised to 190 ℃ and the phenol formed was distilled off for 60 minutes. The temperature was now raised to 235 ℃, after 30 minutes the vacuum was adjusted to 60 mbar and 292.50 g (0.52 mol) Pripol 1009 were added. After a further 15 minutes the temperature was adjusted to 250 ℃ and then the vacuum was adjusted to 5 mbar. After a further 15 minutes the temperature was raised to 280 ℃ and after 15 minutes the vacuum was adjusted to 0.5 mbar, followed by adjustment of the temperature to 300 ℃ and stirring of the mixture for a further 90 minutes. The results are summarized in table 1.

Comparative example 2

Weighing 107880 g (3.48 mol) of bisphenol TMC, 908.29 g (4.24 mol) of diphenyl carbonate and 0.2469 g (4X 10 g)^-4Moles) phenoltetraphenylphosphonium (as mixed crystals having 30% by weight of phenol based on the mixed crystals) were charged to a vessel with a stirrer. The vessel was evacuated and purged with nitrogen (three times) to exclude atmospheric oxygen, and the mixture was melted at 150 ℃ and 100 mbar. The temperature was raised to 190 ℃ and the phenol formed was distilled off for 60 minutes. The temperature was now raised to 235 ℃ and 292.50 g (0.52 mol) of Pripol 1009 were added, and after 30 minutes the vacuum was adjusted to 60 mbar. After a further 15 minutes the temperature was adjusted to 250 ℃ and then the vacuum was slowly adjusted to 5 mbar and the temperature rose to 280 ℃. A vacuum of 1 mbar is then applied, the temperature is adjusted to 300 ℃ and the mixture is stirred for a further 90 minutes. The results are summarized in table 1.

Comparative example 3

53.94 g (0.174 mol) of bisphenol TMC, 45.84 g (0.214 mol) of diphenyl carbonate, 5.99 g (0.026 mol) of dodecanedioic acid and 0.0494 g (8X 10 mol) of dodecanedioic acid are weighed out^-5Moles) phenolated tetraphenylphosphonium (measured as mixed crystals with 30% by weight of phenol based on the mixed crystals) which were charged to a 500 ml three-neck flask equipped with a stirrer, an internal thermometer and a Vigreux column with bridge (30 cm, mirror coating). The apparatus was evacuated and purged with nitrogen (three times) to exclude atmospheric oxygen, and the mixture was melted at 150 ℃. The temperature was raised to 190 ℃ and the phenol formed was distilled off for 30 minutes. A vacuum of 100 mbar is now applied and after 20 minutes the temperature is raised to 235 ℃. After 15 minutes the vacuum was adjusted to 60 mbar and after a further 15 minutes the temperature was adjusted to 250 ℃. After a further 15 minutes the vacuum was increased to 5 mbar and after a further 15 minutes the temperature was increased to 280 ℃. After 15 minutes the vacuum was adjusted to 0.5 mbar and the temperature was raised to 300 ℃ over 15 minutes and the mixture was stirred for a further 30 minutes. The results are summarized in table 1.

Comparative example 4

41.09 g (0.180 mol) of bisphenol A and 49.27 g (0.23 mol) of carbonic acid bis (ester)Phenyl ester, 4.61 g (0.02 mol) of dodecanedioic acid and 0.1225 g (2X 10 g)^-6Moles) phenolated tetraphenylphosphonium (measured as mixed crystals with 30% by weight of phenol based on the mixed crystals) which were charged to a 500 ml three-neck flask equipped with a stirrer, an internal thermometer and a Vigreux column with bridge (30 cm, mirror coating). The apparatus was evacuated and purged with nitrogen (three times) to exclude atmospheric oxygen, and the mixture was melted at 150 ℃. The temperature was raised to 190 ℃ and the mixture was stirred for 30 minutes. The phenol formed was then distilled off at 100 mbar for 20 minutes. The temperature was now raised to 235 ℃ and after 15 minutes the vacuum was adjusted to 60 mbar and after a further 15 minutes the temperature was adjusted to 250 ℃. After a further 15 minutes the vacuum was increased to 5 mbar and after a further 15 minutes the temperature was increased to 300 ℃. After 15 minutes the vacuum was adjusted to 0.5 mbar and the temperature was raised to 300 ℃ over 15 minutes and the mixture was stirred for 30 minutes. The results are summarized in table 1.

Comparative example 5

30 g of methylene chloride and 40 g of water were placed in a2000 ml three-necked flask equipped with a stirrer, a thermometer and a reflux condenser. A solution 1 of 81 g of TMC bisphenol in 400 g of water and 59 g of 49% NaOH, 22 g of dimerized fatty acid and 60 g of phosgene in 520 g of methylene chloride, a solution 2 of 1.35 g of p-tert-butylphenol and 0.34 g of ethylpiperidine in 70 g of methylene chloride are metered simultaneously and added to the solution contained in the flask over a period of 10 minutes. At the same time 210 g of 25% NaOH were added to adjust to an alkaline pH of > 11. The mixture was stirred for a further 15 minutes after the end of the addition to complete the reaction. The organic phase is then separated and subsequently washed with dilute acid and then with demineralized water until the washed phase is virtually free of electrolytes. The organic phase is concentrated by evaporation and dried in a vacuum drying cabinet at 80 ℃ for 16 hours under vacuum with water injection.

TABLE 1

Examples	Eta rel.	Number of colors	％OH	x	y	z	Q
								Example 1	1.175	0.166	0.021	19.7	0	0	1
Example 2	1.179	0.157	0.036	18.8	0	0	1
								Example 3	1.170	0.139	0.020	19.3	0	0	1
Example 4	1.172	0.089	0.037	8.8	0	0	1
								Example 5	1.210	0.051	0.075	7.7	0	0	1
Comparative example 1	1.183	0.522	0.006	18.6	0	0	1
								Comparative example 2	1.179	0.455	0.012	18.2	0	0	1
Comparative example 3	1.150	0.205	0.007	8.4	0	0	1
								Comparative example 4	1.227	1.000	0.006	9.1	0	0	1
Comparative example 5	1.186		0.073	19.0	0.04	0.015	1.4

These examples clearly show the surprising advantage of the polyester carbonates according to the invention, which are markedly superior in terms of the colour number compared with polyester carbonates prepared by conventional esterification processes (i.e.all the educts are reacted with one another simultaneously and/or heated to 300 ℃ C. in one step), for the same Q value.

Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.

Claims (12)

1. A transesterification process for the preparation of a polyester, the process comprising: in a first stage, a first mixture comprising at least one dihydroxy compound and at least one diaryl carbonate is heated in an inert atmosphere at 200-290 ℃ for 30-300 minutes to form a polycondensate, in a second stage at least one dicarboxylic acid is added to the polycondensate to form a second mixture, the second mixture is heated in the presence of a quaternary onium compound as catalyst at a temperature of not more than 290 ℃ for 60-200 minutes to form a polyestercarbonate, and the hydroxyaryl compound formed during the entire course of the process is removed by distillation under reduced pressure.

2. The method of claim 1, wherein the heating in said first stage is for a period of 40 to 150 minutes.

3. The method as claimed in claim 1, wherein in the first stage, heating is carried out at 230-290 ℃.

4. The method as claimed in claim 1, wherein in the first stage, the heating is carried out at 250 ℃ and 280 ℃.

5. The method of claim 1, wherein the heating in the second stage is for 90 to 180 minutes.

6. The method of claim 1, wherein the quaternary onium compound is a phosphonium compound.

7. The method of claim 6, wherein the phosphonium compound is tetraphenylphosphonium phenolate.

8. The method of claim 1, wherein the catalyst is present in an amount of 0.0001 to 0.5 mole percent based on the total molar amount of dicarboxylic acid and dihydroxy compound.

9. A polyestercarbonate obtainable by the process of claim 1.

10. A polyester carbonate, characterized in that it has a colour number of < 0.2 and a characteristic value Q of less than 1.3, whereinx is the weight percent of esterified acid in the polyestercarbonate, y is the weight percent of free COOH in the polyestercarbonate, and z is the amount of anhydride structural units in the polyestercarbonate in weight percent.

11. A method of using the polyestercarbonate of claim 9, comprising preparing a molding composition.

12. A molded article comprising the polyestercarbonate of claim 9.