WO2023208897A1

WO2023208897A1 - Polyester carbonate blend and its production via a polyester carbonate prepolymer

Info

Publication number: WO2023208897A1
Application number: PCT/EP2023/060755
Authority: WO
Inventors: Alexander Meyer; Ulrich Liesenfelder; Lukas Fabian SCHULZ; Paul Buijsen
Original assignee: Covestro Deutschland Ag
Priority date: 2022-04-29
Filing date: 2023-04-25
Publication date: 2023-11-02
Also published as: CN117500859A

Abstract

The present invention relates to a method for producing a polyester carbonate prepolymer, a polyester carbonate prepolymer, a method for producing a polyester carbonate blend using the polyester carbonate prepolymer, a polyester carbonate blend and a use of the polyester carbonate prepolymer.

Description

POLYESTER CARBONATE BLEND AND ITS PRODUCTION OVER A

POLYESTER CARBONATE PREPOLYMER

The present invention relates to a process for producing a polyestercarbonate prepolymer, a polyestercarbonate prepolymer, a process for producing a polyestercarbonate blend using the polyestercarbonate prepolymer, a polyestercarbonate blend and a use of the polyestercarbonate prepolymer.

Polyester carbonates, which contain ester blocks of iso- and/or terephthalic acid and resorcinol, have good weather resistance. These materials are particularly interesting because they do not require painting to protect them from harmful weather conditions and especially from UV light. The ester structures made from resorcinol and iso- and/or terephthalic acid can undergo so-called photo-Fries rearrangements when they come into contact with UV light. This creates, among other things, hydroxybenzophenone structures that are built into the polymer chain. Hydroxybenzophenones are known to have UV absorption properties. This explains the good weather resistance. This situation is described, for example, in US20030050400 Al. The alternative use of UV absorbers, on the other hand, is far less effective because most of the UV absorber accumulates in the mass of the molded part. The concentration of UV absorbers on the surface of a molded part, which must be protected in particular against UV light, is relatively low. If the expert wants to use higher concentrations of UV absorbers, he is confronted with further disadvantages. Low molecular weight compounds reduce the mechanical properties, especially in higher concentrations. This is undesirable. In order to anchor higher concentrations of UV absorbers in the surface, it is common practice to protect UV-sensitive materials such as polycarbonate with layers of lacquer that have high concentrations of UV absorbers. However, painting is an additional step that incurs costs and is not always the preferred solution for sustainability reasons. Particularly in the area of automotive exterior applications, it is advantageous if materials are intrinsically weather-stable and complex painting is not necessary.

In the prior art, the polyester carbonates described are produced using a phase interface process. In this process, aromatic diols and OH-terminated ester blocks are condensed using phosgene. The OH-terminated ester blocks can also be prepared by condensation with phosgene starting from aromatic diacids and aromatic diols in solution. Such a process for producing the oligoesters and the corresponding polyester carbonates is described in WO0026275 Al. The preferred polymers described in this document are polyester carbonates made from bisphenol A containing ester blocks made from resorcinol and terephthal/isophthalic acid. The ester blocks are produced in a dichloromethane/water mixture using aqueous NaOH solution starting from the Acid chlorides of aromatic diacid and resorcinol. The polyester solution containing hydroxy-terminated ester blocks is transferred to a phosgenation reactor. In the preferred case, alkaline bisphenol A solution is introduced and the reactants are reacted with phosgene.

According to DE60212172T2, the polyester carbonates described are obtained by means of solid-state polymerization. The process described is relatively complex because a step must always be carried out in which the polycarbonate used is at least partially crystallized. In addition, the document shows that in particular the use of activated carbonate sources (such as methyl salicylate-capped polycarbonate) achieves sufficient molecular weights of the polyester carbonate and that randomization of the groups can be at least partially suppressed. This document only uses OH-terminated oligoester blocks (i.e. the terminal groups of the oligoester are usually resorcinol). This results in the same connections between the oligoester and the polycarbonate as described above for the phase interface process (see also Figure 2). The document explicitly states that the melt process is not suitable for producing such polyester carbonates because random copolymers result (i.e. the polyester blocks degrade and randomly distribute throughout the polymer). This alone shows that the reaction conditions of a solid-state polymerization cannot be transferred to those in a melt process.

Processes based on the melt transesterification process known for polycarbonate are known and have the advantage that starting materials that are difficult to handle, such as phosgene, can be dispensed with. They also have the great advantage that no solvents are necessary. Therefore, it would be industrially advantageous to produce polyester carbonates using the melt transesterification process. However, this process also involves challenges. The highly reactive acid chlorides are difficult to replace with other input materials. Transesterification processes often have long residence times in corresponding reactors. Due to the high temperatures, by-products often arise, which have a negative impact on product quality. Since melt transesterification processes usually do not require complex processing steps, impurities as well as catalyst residues remain in the product. These can worsen the product quality.

Furthermore, polycarbonates that are produced in the melt transesterification process have significantly higher contents of hydroxy-terminated end groups (content of phenolic OH groups) in comparison with corresponding products from the phase interface process. These phenolic OH groups can be damaged by oxidative processes, which deteriorates product quality. The optical properties in particular suffer. It is However, it is important to maintain good optical properties, especially for a product that is supposed to be characterized by high intrinsic weather stability. It is therefore advantageous if the content of phenolic OH end groups in the resulting polymer is low. However, there is no teaching on this in the prior art regarding the polyester carbonates mentioned, since the prior art relates exclusively to the production of the polyester carbonates by means of a phase interface reaction.

Since, for the reasons mentioned above, the reactivity of the reactants is lower - compared to the starting materials in the phase interface process - it is also unknown how the above-mentioned polyester carbonates with high viscosity or Molecular weight can be produced.

The production of oligoester blocks from aromatic diacids such as isophthalic acid and/or terephthalic acid and aromatic diols such as resorcinol is known. This is described, for example, in the not yet disclosed application EP21179513.3. The aromatic diacids and the aromatic diols are reacted using DPC. Using this process it is possible to produce oligoesters with different end groups, for example OH end groups or phenyl ester or phenyl carbonate end groups.

Surprisingly, however, it was found that when such oligoesters react with aromatic polycarbonate prepolymers, the content of ester structures consisting of corresponding isophthalic acid and/or terephthalic acid and corresponding aromatic diol, in particular resorcinol, in the polyester carbonate is present, but is not sufficient to provide good intrinsic weather stability . If the concentration of such structural elements is low, significantly fewer Fries products result - especially hydroxy-benzophenone structures. However, the intrinsic stabilization against UV light is therefore significantly lower. This finding was surprising since there is no evidence from the prior art that the above-mentioned structural elements are lost during transesterification.

WO2005021616 Al describes the production of hydroxy-terminated oligoester blocks in the melt. Here it was investigated how a content of OH end groups in the oligoesters can be achieved, which is comparable to oligoesters that can be achieved in a process with a solvent. Different catalysts and the influence of driving style (e.g. different temperatures and vacuum) are also tested for this purpose. In addition, the oligoesters are then condensed into a polyester carbonate using a phase interface process. Therefore, this document cannot contain any teaching as to how the ester structures formed from isophthalic acid and/or terephthalic acid and resorcinol are retained in the production of a polyester carbonate by means of melt transesterification. In WO2006057810 Al, oligoesters are described using the melt transesterification process, which are characterized in that they have a high proportion of carboxyl end groups. These carboxyl end groups are then used to incorporate the oligoesters into paint systems. Accordingly, the use of oligoesters in a melt transesterification process is not described here.

US20030050400 Al describes the production of oligomers from aromatic diacids and resorcinol. The US20030050400 Al is based on the task of providing OH-terminated building blocks, which can then be converted into polyester carbonates using phase interface processes. Similar to WO2005021616 Al, only the phase interface process is reported here and conclusions about the preservation of the desired ester structures in a melt process are therefore not possible.

Based on this prior art, the present invention was based on the object of overcoming at least one disadvantage of the prior art. In particular, the present invention was based on the object of providing a polyester carbonate blend comprising ester blocks based on isophthalic acid and/or terephthalic acid and an aromatic diol, preferably resorcinol, which are accessible by a melt transesterification process. The corresponding polyester carbonate blends should contain the highest possible concentrations of ester structures made from aromatic acid and aromatic diol (not bisphenol). It was therefore an aspect of this invention that the resulting polyester carbonate blends have good intrinsic weather resistance. This should in particular result from intact ester groups from isophthalic acid and/or terephthalic acid and the aromatic diol, in particular resorcinol or a derived compound. These intact groups are able to form hydroxybenzophenone structures and thus give the polyester carbonate blend UV absorption properties. This allows the intrinsic weather stability to be increased. The polyester carbonate blends should preferably also have good processability. Very particularly preferably, the blends should at the same time have the lowest possible phenolic OH end group content. The polyester carbonate blends should therefore preferably be weather-stable and/or essentially yellowing-stable and/or essentially not prone to polymer degradation, for example through oxidative degradation. It is also preferred that no raw materials that present challenges in handling, such as phosgene, are used in the production of the polyester carbonate blend. In addition, a process for producing polyester carbonate blends should be provided which is as simple as possible, that is to say, for example, comprising as few and/or inexpensive and/or energy-intensive steps as possible. At least one, preferably all, of the above-mentioned tasks have been solved by the present invention. Surprisingly, it was found that when an oligoester containing ester linkages between isophthalic acid and/or terephthalic acid and resorcinol or a compound derived from resorcinol is mixed with oligocarbonate and/or polycarbonate according to the method according to the invention or is thermally processed together with polycarbonate, a high Proportion of ester structures from aromatic diol (not bisphenol) and isophthalic acid and / or terephthalic acid can be obtained in the resulting polyester carbonate blend. If a high amount of oligoester is reacted with a small amount of oligo- and/or polycarbonate in the first process step and in a second process step the resulting polyester carbonate prepolymer is reacted with a large amount of polycarbonate, a polyester carbonate blend with a high proportion on ester structures from aromatic diol and aromatic acid can be obtained. The process according to the invention using the special polyester carbonate prepolymers results in a polyester carbonate blend being obtained in which a high proportion of the isophthalic acid and/or terephthalic acid groups are directly linked to the aromatic diol such as resorcinol. In addition, ester linkages from aromatic bisphenol such as bisphenol A and aromatic diacid are also included.

Without wishing to be bound to any theory, the first process step, in which the oligoester is converted in a large excess to the oligo- and/or polycarbonate, appears to lead to a polyestercarbonate prepolymer in which the few carbonate units are bound to the oligoester, to lead to good compatibility with the polycarbonate to be used in the second process step. This makes it possible for both the polyestercarbonate prepolymer and the polycarbonate to be converted into a homogeneous mixture in the second process step. This homogeneous mixture has both good optical and mechanical properties. In addition, under these conditions, a large part of the isophthalic acid and/or terephthalic acid ester to the aromatic diol, which differs from bisphenol A, remains, so that the resulting blend is also intrinsically weather-stable.

In addition, the polyester carbonate blend can be produced in a solvent-free process. In particular, the use of substances that are difficult to handle, such as phosgene, can be dispensed with. Likewise, the method according to the invention only has a few steps (in particular no complex step of crystallization, for example of the polycarbonate). Additionally, these steps do not require the presence of a solvent (such as crystallization). The polyester carbonate blend is therefore accessible using a simple and ecologically and/or economically advantageous process. In particular, the method according to the invention is also capable of scale-up. This preferably means that the method according to the invention also can be carried out on an industrial scale. This shows in particular that the method according to the invention can be controlled and thus the scale can be increased predictably.

In addition, according to the process according to the invention, a prepolymer and/or a blend can be provided without the use of an activated carbonate source (such as an oligocarbonate or a polycarbonate with 2-methoxycarbonylphenoxy end groups, see also DE60212172T2). Such activated carbonate sources are usually more expensive than classic “unactivated” groups (e.g. an oligocarbonate or a polycarbonate with phenoxy end groups) and, above all, have to be produced separately in an additional step.

According to the invention, there is therefore provided in one aspect a process for producing a polyestercarbonate prepolymer, comprising the steps

(a) providing an oligoester comprising structures of the formula (I),

in which Ri independently represents a hydrogen atom, a halogen or an alkyl group with 1 to 4 carbon atoms and n is at least 4,

(b) providing an oligocarbonate and/or a polycarbonate and

(c) reacting 65 to 95% by weight of the oligoester from step (a) with 35 to 5% by weight of the oligocarbonate and / or polycarbonate from step (b), the% by weight being the sum of Weight of oligoester from step (a) and of oligocarbonate and / or polycarbonate from step (b), by means of condensation reaction in the melt to obtain a polyestercarbonate prepolymer.

The production of an oligoester from process step (a) is known in the prior art. For example, a corresponding process is disclosed in WO2005/021616 A1 for producing, in particular, OH-terminated oligoesters (see, for example, Example 1 of WO2005/021616A1). Likewise, a process for producing an oligoester is described in the not yet disclosed application EP21179513.3. It is preferred that the oligoester of step (a) is prepared in the absence of a solvent. This means that no further purification steps are necessary to implement the oligoester in step (c) according to the invention.

The oligoester of step (a) is particularly preferably prepared by a process in which

[I] at least isophthalic acid and / or terephthalic acid are mixed with a diol of the formula (3) and at least one diaryl carbonate of the formula (4), whereby

in which Ri represents a hydrogen atom, a halogen or an alkyl group with 1 to 4 carbon atoms, preferably hydrogen and where

in which R2 each independently represents hydrogen or -COOCH3, preferably hydrogen,

[II] this mixture from step [I] is heated in the presence of at least one catalyst and

[III] vacuum is applied to the mixture from step [II] to obtain the oligoester.

The workup of the oligoester - if necessary and/or desired - can be carried out in a manner known to those skilled in the art, for example by precipitation. However, it is preferred that no solvents are used during the workup.

It will be apparent to the person skilled in the art that R ¹ , for example in formula (I), formula (3), formula (300), formula (la) and/or formula (7), is chosen from the position in such a way that the photo- Frieze rearrangements are possible. For example, not all ortho positions may be blocked by R ¹ . However, the possible substitution pattern is obvious to the person skilled in the art based on his or her specialist knowledge.

According to the invention, an “aromatic diol” is sometimes spoken of. This term is used in particular to distinguish it from a “bisphenol” (it is also often pointed out that an aromatic diol does not mean a bisphenol). It is known to those skilled in the art that a bisphenol in the broadest sense is also an aromatic diol. However, in the context of the present invention, he can make a corresponding distinction based on his Expertise (particularly when it comes to which structures have intrinsic UV activity and which do not). An aromatic diol is preferably understood to mean a structure of the formula (3). An aromatic diol is particularly preferably understood to mean resorcinol or a compound derived from resorcinol. A “bisphenol” in the sense of the present invention is preferably a compound which is represented by formula (III) (see also “Y” in formula (II), where in formula (III) an OH group is present on each ( The structure of formula (III) is therefore a bisphenol structure, which was created by the reaction of the OH groups; this connection is known to the person skilled in the art). A particularly preferred bisphenol is bisphenol A.

Just as optionally, the process described can have a further step in which the oligoester is reacted with a diacid diphenyl ester, preferably isophthalic acid diphenyl ester and/or terephthalic acid diphenyl ester. Such a reaction can reduce the OH end group content if desired.

The oligoester of process step (a) can be OH-terminated, phenyl ester-terminated, acid-terminated or phenylcarbonate-terminated, or contain mixtures of the end groups mentioned. The oligoester is preferably OH-, phenylester-, phenylcarbonate-terminated or any mixture of the aforementioned terminations is present. The person skilled in the art can adapt the process according to the invention to the end group(s) contained. For example, the termination can be influenced by the composition/ratio of the monomers used, the reaction temperature, the catalyst used, the application and also the strength of vacuum. This can also influence the viscosity and the resulting glass transition temperature of the oligoester.

It is particularly preferred that the oligoester of process step (a) according to the invention at least partially has no OH terminations. The resulting polyestercarbonate prepolymer or the resulting polyestercarbonate blend thus preferably has essentially no, particularly preferably no, links from, for example, resorcinol to, for example, BPA via a carbonate bridge. Particularly preferably, the polyestercarbonate prepolymer according to the invention and/or the polyestercarbonate blend according to the invention (both described further below) have essentially no, particularly preferably no, structures of the formula (300),

where in the structure of the formula (300) Ri independently represents a hydrogen atom, a halogen or an alkyl group with 1 to 4 carbon atoms, preferably represents the meanings given for Ri of the formula (la), Y independently represents a structure of the formulas (III), (IV), (V) or (VI), preferably stands for the meanings given for formula (II) and the “*” each indicate the positions with which the structure of the formula (300) is inserted into the Polymer chain of the polyester carbonate attaches/would attach.

The phrase “essentially no structures of formula (III)” is understandable to those skilled in the art. It can be seen that traces of such groups may be present due to impurities. However, according to the invention, they are preferably avoided.

In particular, it is preferred that the oligoester of process step (a) according to the invention has at least partially no OH terminations and that the polyestercarbonate prepolymer according to the invention is particularly preferably obtained via this process.

For example, in step (I), the resulting end group ratio in the oligoester can preferably be influenced by the molar ratio of isophthalic acid and/or terephthalic acid to the diol of the formula (3). The molar ratio of isophthalic acid and/or terephthalic acid to the diol of the formula (3) is preferably 0.50 to 1.20, particularly preferably 0.70 to 1.15, very particularly preferably 0.75 to 1.12.

According to the invention, the diol of the formula (3) is preferably also referred to as “resorcinol or a compound derived from resorcinol”. This preferably means that if a substituent Ri is present, a compound derived from resorcinol is present which has the substituent Ri with the meanings given.

Both isophthalic acid and terephthalic acid are preferably used in process step (I). If both diacids are used, then it is additionally preferred that the molar ratio of isophthalic acid to terephthalic acid is 0.25-4.0 to 1, particularly preferably 0.4-2.5 to 1 and very particularly preferably 0.67-1 .5 to 1. It is also preferred that the diol of formula (3) is resorcinol. Likewise and preferably at the same time, it is preferred that the diaryl carbonate of the formula (4) is diphenyl carbonate.

A molar ratio of isophthalic acid and/or terephthalic acid to the diaryl carbonate of formula (4) of 1 to 2 - 2.5 is particularly preferred, more preferably 1.0 to 2.01 - 2.25 and most preferably 1.0 used at 2.05.

In process step (II), the mixture from process step (I) is heated in the presence of at least one catalyst. In this process step (II), the individual components from process step (I) are preferably melted. However, terephthalic acid in particular is among the not soluble under the given conditions, at least initially. However, this can change in the course of process step (II). Carbon dioxide is generally released in process step (II). This procedure allows a quick reaction under low temperature stress. Process step (II) is preferably carried out under a protective gas atmosphere, preferably under nitrogen and/or argon. Step (II) preferably takes place in the absence of a solvent. The term “solvent” is known to those skilled in the art in this context. According to the invention, the term “solvent” is preferably understood to mean a compound that does not enter into a chemical reaction in any of the process steps (I), (II) and/or (III). Excluded are those compounds that are formed by the reaction (for example phenol when diphenyl carbonate is used as diaryl carbonate). Of course, it cannot be ruled out that the starting compounds contain traces of solvents. This case should preferably be included according to the invention. However, according to the invention, an active step of adding such a solvent is preferably avoided.

The heating in process step (II) is preferably carried out at temperatures of 180 ° C to 320 ° C, preferably 190 ° C to 310 ° C and particularly preferably from 230 ° C to 300 ° C. Under these temperature conditions it may be that the corresponding aryl alcohol of the diaryl carbonate, preferably phenol, is already distilled off. Process step (II) is preferably carried out under normal pressure. Stirring is preferably carried out under normal pressure until the evolution of gas essentially stops. Alternatively, the temperature can also be increased gradually - depending on the reactivity observed - to 200 ° C - 320 ° C, preferably 210 - 310 ° C, particularly preferably 215 - 300 ° C. The reactivity can be estimated via gas evolution in a manner known to those skilled in the art. In principle, higher temperatures are also possible in this step, but side reactions can occur at higher temperatures (e.g. discoloration). Therefore, higher temperatures are less preferred.

The at least one catalyst is particularly preferably an organic base or a Lewis acidic transition metal compound. The organic base is preferably alkylamines, imidazole (derivatives), guanidine bases such as triazabicyclodecene, DMAP and corresponding derivatives, l,5-diazabicyclo[4.3.0]non-5-ene (DBN) and diazabicycloundecene (DBU), am most preferred DMAP. These catalysts have the particular advantage that they can be separated in process step (III) according to the invention by the applied vacuum. This means that the resulting mixture, containing oligoesters, only contains a small amount or no catalyst at all. This has the particular advantage that no inorganic salts, which are always obtained, for example, via a route in which phosgene is used, are present in the mixture of oligoesters and therefore not in the later polyester carbonate. It is known that such salts can negatively affect the stability of the polyester carbonate because the ions can have a catalytic effect with corresponding degradation. A mixture of at least one organic base, such as alkylamines, imidazole (derivatives), guanidine bases such as triazabicyclodecene, DMAP and corresponding derivatives, DBN or DBU, is preferably used together with a phosphonium catalyst of the formula (VIII) (see below). A mixture of 4-(dimethylamino)pyridine (DMAP) and tetrabutylphosphonium acetate is particularly preferably used as the catalyst in process step (II).

If the catalyst is a Lewis acidic transition metal compound, it is preferred that alkoxides of metals from Group IVB or of tin or derivatives of metals, metal oxides or metal carboxylates from Group IVA of the periodic table are used. The Lewis acidic transition metal compound is particularly preferably selected from the group consisting of titanium butoxide (Ti(OBu)4), titanium isopropoxide (Ti(OiPr)4), titanium phenoxide (TiOPhü), antimony trioxide, zirconium butoxide (Zr(OBu)4), dialkyltin dialkoxides, dibutyltin oxide , dibutyltin diester, tin phenoxide, monobutyltin oxide and any mixture of the aforementioned. Titanium butoxide is particularly preferred.

The at least one catalyst is preferably in amounts of 1 to 5000 ppm, preferably 5 to 1000 ppm and particularly preferably 20 to 500 ppm, based on the sum of the masses of isophthalic acid and / or terephthalic acid, the diol of formula (3) and the diaryl carbonate the formula (4) is used. If more than one catalyst is used in the reaction, these catalysts are preferably used in total in amounts of 1 to 5000 ppm, preferably 5 to 1000 ppm and particularly preferably 300 to 700 ppm.

In process step (III), vacuum is applied to the mixture obtained from process step (II). As a result, the corresponding aryl alcohol of the diaryl carbonate used, preferably phenol, is distilled off and the equilibrium of the reaction is shifted towards oligoesters. Aryl alcohol is the chemical compound split off by the condensation reaction.

The term “condensation” or “condensation reaction” is known to those skilled in the art. This is preferably understood to mean a reaction in which two molecules (of the same substance or different substances) combine to form a larger molecule, with one molecule of a chemically simple substance being split off. This compound split off during the condensation is removed in process step (III) using vacuum. Accordingly, it is preferred that the process according to the invention is characterized in that during process step (III), the volatile components which have a boiling point below the mixture of oligoestems formed in process step (II) are separated off, if necessary by gradually reducing the pressure. A stepwise separation is preferably chosen if different volatile components are separated off. A gradual separation is also preferably chosen in order to achieve the most complete separation possible of the volatile component(s). The volatile components are the chemical compound or compounds split off during the condensation, preferably phenol.

The condensation product is separated off in process step (III) preferably at temperatures of 200 ° C to 280 ° C, particularly preferably 210 ° C to 270 ° C and particularly preferably 220 ° C to 265 ° C. Furthermore, the vacuum during separation is preferably 500 mbar to 0.01 mbar. In particular, it is preferred that the separation takes place step by step by reducing the vacuum. The vacuum in the last stage is very particularly preferably 10 mbar to 0.01 mbar.

The oligoester obtained in this way can, if necessary, be used in process step (a) after further purification. It is preferred that the oligoester of step (a) has a number-average molecular weight Mn of 500 g/mol to 8000 g/mol, preferably 600 g/mol to 5000 g/mol and particularly preferably 700 g/mol to 3000 g/mol having. Unless otherwise stated, this M _n and/or all other molecular weights of the invention are preferably determined via gel permeation chromatography in dichloromethane with a bisphenol A polycarbonate as a standard. The molecular weights according to the invention Mw (weight average) and Mn (number average) of the oligesters, oligocarbonates, polycarbonates or polyester carbonates used were - unless otherwise stated - using size exclusion chromatography (gel permeation chromatography GPC; based on DIN 55672-1:2007-08 using a BPA Polycarbonate calibration). The calibration was carried out with linear polycarbonates of known molecular weight distribution (e.g. from PSS Polymer Standards Service GmbH, Germany). The method 2301-0257502-09D (from 2009 in German) from Currenta GmbH & Co. OHG, Leverkusen was used. Dichloromethane was used as eluent. The column combination consisted of cross-linked styrene-divinylbenzene resins. The GPC can comprise one or more commercially available GPC columns for size exclusion chromatography connected in series, which are selected so that an adequate separation of the molar masses of polymers, in particular of aromatic polycarbonates with weight-average molar masses M _w of 2,000 to 100,000 g/mol, is possible . Typically the analytical columns have a diameter of 7.5 mm and a length of 300 mm. The particle sizes of the column material are in the range from 3 pm to 20 pm.

It is also preferably possible for the oligoester to have a number average molecular mass in the range from 1000 g/mol to 16000 g/mol, particularly preferably 1200 g/mol to 10000 g/mol and very particularly preferably 2000 g/mol to 8000 g/mol having. In this special case, the M _n is preferably measured via GPC with polystyrene calibration in THF. The calibration is preferably carried out with polystyrenes in a molecular weight range of 500 to 7,000,000 g/mol. The GPC is preferably carried out in tetrahydrofuran (preferably THF stabilized with 0.007-0.015% by weight of butylhydroxytoluene), which has been modified with 0.8% acetic acid. The flow rate is preferably 1 mL/min at 40 °C. The column combination Waters Acquity® APC™ Column Manager - S with three Acquity® APC™ columns (450Ä, 125Ä and 45Ä pore diameter) with I/d = 150/4.6 mm and which contain particles with a particle diameter of 2.5 ( the 450Ä and the 125Ä column) or 1.7 sqm (the 45Ä column) (1 pm = IxlO ^-6 m) are used. Detection is carried out here using a refractive index detector. The oligoester of step (a) preferably has as end groups at least one type of end group, which is selected from the group consisting of -OH end groups (e.g. from terminal resorcinol), -COOH end groups, isophthalic acid / terephthalic acid - Ester-phenol end groups or resorcinol carbonate-phenol end groups. These end groups can also be present in any mixtures. They can also be present in any quantities or ratios to one another.

Further chemical properties of the oligoester are described, for example, in WO 2005/021616 Al. With regard to these chemical properties of the oligoester, the content of WO 2005/021616 A1 is hereby incorporated by reference into the present disclosure.

In process step (b), an oligocarbonate and/or a polycarbonate is provided. According to the invention, the term “oligo” carbonate or “oligo” ester is used in particular to distinguish it from the term “poly” carbonate. The definition of “oligo” and “poly” is known to those skilled in the art. In particular, this means that, for example, a polycarbonate has a higher number of repeating units and therefore a higher molecular weight than an oligocarbonate. According to the invention, the term “oligo”mer is preferably used when the substance concerned does not have sufficient mechanics on its own. However, a corresponding “polymer” does. According to the invention, a sharp separation of the two terms does not seem to be decisive. Nevertheless, it is preferred that the oligocarbonate of step (b) has a relative solution viscosity of 1.08 to 1.22, preferably 1.11 to 1.22, particularly preferably 1.13 to 1.20. It is also preferred that the polycarbonate of step (b), but also of step (iii) of the process according to the invention for producing a polyestercarbonate blend, has a weight-average molecular weight Mw of 24,000 g/mol to 40,000 g/mol, particularly preferably of 24,500 g /mol to 34,000 g/mol, very particularly preferably from 25,000 g/mol to 32,000 g/mol determined by gel permeation chromatography, calibrated against bisphenol A polycarbonate standards using dichloromethane as eluent. Likewise preferably, the polycarbonate of step (b) and/or step (iii) has a relative solution viscosity of greater than 1.20 to 1.36, particularly preferably greater than 1.22 to 1.35 and most preferably greater than 1 .27 to 1.34. According to the present invention, the relative solution viscosity (r|rel; also referred to as eta rel) is preferably determined in dichloromethane at a concentration of 5 g/1 at 25 ° C using an Ubbelohde viscometer. The person skilled in the art is familiar with the determination of the relative solution viscosity using a Ubbelohde viscometer. According to the invention, this is preferred according to DIN 51562-3; Carried out 1985-05. The throughput times of the polyester carbonate to be measured are measured using the Ubbelohde viscometer in order to then determine the difference in viscosity between the polymer solution and its solvent. To do this, the Ubbelohde viscometer is first calibrated by measuring the pure solvents dichloromethane, trichlorethylene and tetrachlorethylene (always at least 3 measurements and a maximum of 9 measurements). The actual calibration then takes place with the solvent dichloromethane. The polymer sample is then weighed, dissolved in dichloromethane and the flow time for this solution is then determined three times. The average of the flow times is corrected using the Hagenbach correction and the relative solution viscosity is calculated.

It is preferred that the oligocarbonate has a phenolic OH group content of 250 ppm to 2500 ppm, preferably 500 to 2400 ppm, and particularly preferably 1000 to 2300 ppm. The determination of the phenolic OH group content is described below in relation to the polyester carbonate blend.

It is preferred that the oligocarbonate and/or polycarbonate used in process step (b) do not have any end groups of the formula (301).

where in formula (301) the “*” stands for the connection of the structure of formula (301) to the oligocarbonate and/or polycarbonate. This means that no activated carbonate source is preferably used. According to the invention, this is preferably not necessary since the reaction in process step (c) proceeds well under the defined conditions.

In process step (c) according to the invention, the oligoester from step (a) is reacted with the oligocarbonate and/or the polycarbonate, the oligoester always being used in excess of the oligocarbonate and/or polycarbonate. In this case, 65 to 95% by weight of the oligoester from step (a) is reacted with 35 to 5% by weight of the oligocarbonate and/or polycarbonate from step (b). Preference is given to 70 to 93% by weight, particularly preferably 75 to 90% by weight, of the oligoester from step (a) with 30 to 7% by weight, particularly preferably 25 to 10% by weight Oligocarbonate and/or polycarbonate from step (b), the weight percent being based on the sum of the weight of oligoester from step (a) and of oligocarbonate and/or polycarbonate from step (b).

In process step (c) according to the invention, a condensation reaction takes place. The term “condensation reaction” has already been defined above. The person skilled in the art knows how to influence such equilibrium reactions to produce the desired product. In particular, according to the invention, it is preferred that step (c) is carried out at a pressure that is reduced in relation to the ambient pressure. This allows the compound formed during condensation to be removed using a vacuum. Accordingly, it is preferred that the process according to the invention is characterized in that during process step (c) the volatile components which have a boiling point below the polyester carbonate prepolymer formed in process step (c) are separated off, if necessary with a gradual reduction of the pressure. A stepwise separation is preferably chosen if different volatile components are separated off. A stepwise separation is also preferably chosen in order to ensure the most complete separation possible of the volatile component(s). The volatile components are preferably the chemical compound or compounds split off during the condensation, preferably phenol. However, the volatile components can also be the not yet fully reacted diol of the formula (3) and/or the not yet fully reacted diaryl carbonate of the formula (4) and/or low molecular weight oligomers (such as dimers or trimers) with correspondingly low boiling points. Likewise, the person skilled in the art also knows that appropriate temperatures may be necessary in process step (c) in order to obtain appropriate yields of polyester carbonate prepolymer.

It is preferred that the oligoester used in process step (a) and/or the oligocarbonate and/or polycarbonate used in process step (b) are amorphous.

The process according to the invention thus provides a polyestercarbonate prepolymer through the reaction of the oligoester with the oligocarbonate and/or polycarbonate. Therefore, in a further aspect of the present invention, a polyestercarbonate prepolymer is provided, which is obtained by the process according to the invention for producing a polyestercarbonate prepolymer in preferably all of the embodiments described above, in particular also in a combination of preferences. Also provided is a polyester carbonate prepolymer comprising

(A) Ester groups of the formula (la)

in which Ri independently represents a hydrogen atom, a halogen or an alkyl group with 1 to 4 carbon atoms, n is at least 4 and the “*” indicate the positions with which the ester groups are incorporated into the polyester carbonate blend,

(B) Carbonate groups of the formula (II)

in which Y independently represents a structure of the formulas (III), (IV), (V) or (VI), where

in the

R6 and R7 each independently represent hydrogen, Ci-Cis-alkyl, Ci-Cis-alkoxy, halogen or optionally substituted aryl or aralkyl, and

X for a single binding, -o-, -o, -s-, ci to c ₍ ,-alkylene. C2- to CS alkylidi, CE up

Cio-cycloalkylidene or for C - to Ci2-arylene, which may optionally be fused with aromatic rings containing further heteroatoms,

(IV)(V)(VI), where in these formulas (IV) to (VI) R ³ each represents Ci-C4-alkyl, aralkyl or aryl, preferably methyl or phenyl, very particularly preferably methyl, and the “*” each indicate the positions with which the formulas (III), (IV), (V) or (VI) attach to the carbonate group in formula (II), m indicates the average number of repeating units and each indicates the positions with which the carbonate groups are incorporated into the polyester carbonate blend are, wherein at least some of the ester groups (A) are directly linked to one another with at least some of the carbonate groups (B) via the formula (VII), where

(VII), in which Y has the meanings described above for (B) and (A) stands for the attachment to the ester group (A) and (B) stands for the attachment to the carbonate group (B), and which is further characterized thereby is that the polyester carbonate prepolymer contains more mol% of carbon atoms, as marked with an arrow in formula (la), than mol% of carbon atoms, as marked with an arrow in formula (VII),

have. This polyestercarbonate prepolymer is preferably obtained by the process according to the invention for producing a polyestercarbonate prepolymer in preferably all of the configurations described above, in particular also in a combination of preferences.

The determination of the structural formulas (la) and (VII) is described in particular below for the polyester carbonate blend according to the invention. The specialist is able to do all of them The comments on the blend also apply here to the polyester carbonate prepolymer, where applicable and sensible.

The polyestercarbonate prepolymer according to the invention has a higher molecular weight than the starting oligoester of step (a), but its molecular weight depends largely on the oligocarbonate and/or polycarbonate used. The reaction also causes the polyester carbonate prepolymer to have structures of the formula (7):

(7), in which Ri has the meanings given for formula (I), Y has the meanings given below (Y is derived from the bisphenols that were used to produce the oligocarbonate and/or polycarbonate) and the “.. .” represent a logical continuation of the chain (in particular further esters from the oligoester of step (a) or further carbonates from the oligocarbonate and / or polycarbonate from step (b)). Formula (7) shows an ester linkage between an isophthalic acid/terephthalic acid and the bisphenol of the oligocarbonate and/or polycarbonate.

In particular, the polyestercarbonate prepolymer according to the invention, as described, for example, for the process according to the invention, is produced by reacting an oligoester as described above with the oligocarbonate and/or the polycarbonate, the oligoester always being used in excess of the oligocarbonate and/or polycarbonate. Preferably 65 to 95% by weight of the oligoester (for example from step (a), as described above) with 35 to 5% by weight of the oligocarbonate and / or polycarbonate (for example from step (b), as described above) implemented. Preference is given to 70 to 93% by weight, particularly preferably 75 to 90% by weight, of the oligoester (for example from step (a), as described above) with 30 to 7% by weight, particularly preferably 25 to 10% by weight. % of the oligocarbonate and/or polycarbonate (for example from step (b), as described above), the weight % being based on the sum of the weight of oligoester and of oligocarbonate and/or polycarbonate. Accordingly, the polyestercarbonate prepolymer according to the invention preferably has corresponding weight ratios of the different structures with ester groups and structures with carbonate groups.

Furthermore, the polyester carbonate prepolymer according to the invention preferably does not contain any methyl 2-hydroxybenzoate. Traces of such a compound can be detected in the prepolymer, for example by NMR spectroscopy. You can use it in polyester carbonate Prepolymer remain when activated carbonate sources (e.g. oligocarbonates and / or polycarbonates with end groups of formula (301)) are used to produce the polyestercarbonate prepolymer. Likewise, the polyester carbonate prepolymer according to the invention preferably does not have any end group of the formula (301).

According to the invention, it was found that a reaction took place between the oligoester and the oligocarbonate and/or polycarbonate. This could be seen in that the resulting polyestercarbonate prepolymer was essentially transparent. The term “transparent” is here preferably understood as described for the polyester carbonate blend.

According to the invention, it was found that the resulting polyestercarbonate prepolymer is suitable for providing a polyestercarbonate blend by mixing and/or reacting with another polycarbonate, which on the one hand meets the high mechanical and optical requirements of a standard polycarbonate, but at the same time intrinsically Has weather resistance. Without wishing to be bound by theory, the polyestercarbonate prepolymer appears to act as a compatibilizer allowing a homogeneous mixture to be achieved between the ester groups and the polycarbonate. In particular, the polyestercarbonate prepolymer according to the invention is suitable for use in the process according to the invention for producing a polyestercarbonate blend.

In a further aspect of the present invention there is provided a process for producing a polyestercarbonate blend, comprising the steps

(i) providing the polyester carbonate prepolymer according to the invention, preferably in all the configurations described above and also combinations of preferences,

(ii) Providing a polycarbonate with a weight-average molecular weight Mw of 24,000 g/mol to 40,000 g/mol, particularly preferably of 24,500 g/mol to 34,000 g/mol, most preferably of 25,000 g/mol to 32,000 g/mol determined by gel permeation chromatography, calibrated against bisphenol A polycarbonate standard using dichloromethane as eluent,

(iii) converting the polyestercarbonate prepolymer from step (i) and the polycarbonate from step (ii) into a molten state and mixing in the molten state 5 to 25% by weight of the polyestercarbonate prepolymer with 95 to 75% by weight of polycarbonate, where the weight percent refers to the sum of the weight of polyestercarbonate prepolymer from step (i) and polycarbonate from step (ii) to obtain a polyestercarbonate blend. It will be apparent to the person skilled in the art that process step (i) preferably comprises process steps (a) to (c) described above.

The polycarbonate used in process step (ii) can be the same as or different from the polycarbonate optionally used in step (b). However, the process for producing the polyestercarbonate blend according to the invention differs from that for producing the polyestercarbonate prepolymer according to the invention in that in the production of the polyestercarbonate blend according to the invention, on the one hand, a polycarbonate is necessarily used (and not an oligocarbonate) and, on the other hand, this polycarbonate is used Excess to the polyester carbonate prepolymer is used. The use of a polycarbonate (in contrast to an oligocarbonate) in process step (ii) is mandatory, as this is the only way to ensure the good mechanics, preferably comparable to a standard polycarbonate, of the polyester-polycarbonate blend. This polycarbonate is preferably an aromatic polycarbonate. The polycarbonate is very particularly preferably a polycarbonate with repeating units of the formula (II)

in the

X for a simple binding, -o-, -o, -s-, ci to c ₍ ,-alkylene. C2 to CS alkylidi, CE to CIO-CYCLOALKYLIDEN or for CE to CI2 aryles, which if necessary with aromatic rings containing further heteroatoms can be fused,

(IV) (V) (VI), where in these formulas (IV) to (VI) R ³ each represents Ci-C4-alkyl, aralkyl or aryl, preferably methyl or phenyl, very particularly preferably methyl, and the “*” indicates the positions with which the formulas (III), (IV), (V) or (VI) attach to the carbonate group in formula (II), and m indicates the number of repeating units (m can be replaced by the defined molecular weight of the polycarbonate used can be calculated). The polycarbonate of process step (b) is particularly preferably based on bisphenol A.

In process step (iii), the polyestercarbonate prepolymer from step (i) and the polycarbonate from step (ii) are first converted into a molten state. This can be done in a manner known to those skilled in the art by supplying energy. A temperature should be chosen at which both components are in a molten state. In particular, a temperature must therefore be selected which is above the glass transition temperature and/or the melting point, preferably above the glass transition temperature of the polyestercarbonate prepolymer and the polycarbonate. During process step (iii), at least this temperature must be maintained in order to mix the components in the molten state.

In process step (iii), the polyestercarbonate prepolymer is used in excess of the polycarbonate. Preference is given to 8 to 35% by weight, particularly preferably 10 to 30% by weight, very particularly preferably 15 to 25% by weight of the polyester carbonate prepolymer with 92 to 65% by weight, particularly preferably 90 to 70% by weight. -%, very particularly preferably mixed with 85 to 75% by weight of the polycarbonate in the molten state, the weight% being the sum of the weight of polyestercarbonate prepolymer from step (i) and of polycarbonate from step (ii) relate.

In process step (iii), in one embodiment, a reaction can take place between the polyestercarbonate prepolymer and the polycarbonate. This is in particular a condensation reaction, as described in more detail above. In another embodiment, no reaction occurs between the two components. This gives you a physical one Mixture. However, the polyester carbonate blend according to the invention is in any case a single-phase, homogeneous mixture. In particular, according to the invention, the term “homogeneous mixture” means that with regard to the phase morphology there are no two discrete phases that can be distinguished from one another, but only one homogeneous phase. This can be demonstrated in particular by the transparency of the polyester carbonate blends according to the invention. For the purposes of the present invention, “transparent” is preferably understood to mean blends that have a light transmission in the VIS range of the spectrum (380 to 780 nm) of more than 20% (transmittance TVIS), determined according to DIN ISO 13468-2:2006 (D65 , 10°, layer thickness of the sample plate: 4 mm). They also preferably have a haze of less than 10%, determined according to ASTM D1003:2013. In particular, this refers to blends that show visual transparency, ie depict the background and can therefore be used as a transparent cover, for example.

According to the invention, the term “blend” includes both physical mixtures and mixtures in which at least part of the polyestercarbonate prepolymer has reacted with the polycarbonate.

The person skilled in the art is aware of methods with which he can influence whether a reaction in process step (iii) takes place or not. Since the reaction is preferably a condensation reaction, the above statements apply here analogously. In particular, it is preferred if process step (iii) is carried out at a pressure that is reduced in relation to the ambient pressure. This allows the compound formed during condensation to be removed using a vacuum. Accordingly, it is preferred that the process according to the invention is characterized in that during process step (iii) the volatile components which have a boiling point below the polyester carbonate blend formed in process step (ii) are separated off, if necessary with a gradual reduction of the pressure. A stepwise separation is preferably chosen if different volatile components are separated off. A stepwise separation is also preferably chosen in order to ensure the most complete separation possible of the volatile component(s). The volatile components are the chemical compound or compounds split off during condensation.

Likewise, a catalyst that is common to those skilled in the art can be used in process step (iii). However, the process according to the invention is preferably carried out in the absence of a catalyst. This has the advantage that the catalyst does not have to be separated from the resulting polyester carbonate blend or does not remain in it. Depending on the catalyst, this can have an impact on the stability of the polyester carbonate blend. The method according to the invention can also be carried out in the presence of a catalyst, particularly preferably in the presence of a basic catalyst.

Catalysts include all inorganic or organic basic compounds, for example lithium, sodium, potassium, cesium, calcium, barium, magnesium, hydroxides, carbonates, halides, phenolates, diphenolates, fluorides, -acetates, -phosphates, hydrogenphosphates, -boranates, nitrogen and phosphorus bases such as, for example

Tetramethyl ammonium hydroxide, tetramethyl ammonium acetate, tetramethyl ammonium fluoride, tetramethyl ammonium tetraphenyl boranate, tetraphenyl phosphonium fluoride, tetraphenyl phosphonium tetraphenyl boranate, dimethyl diphenyl ammonium hydroxide, tetraethyl ammonium hydroxide, cethyl trimethyl ammonium tetraphenyl boranate, cethyl trimethyl ammonium phenolate, l,8-diazabi cyclo[5.4.0]undec-7- en (DBU), 1,5-diazabicyclo [4.3.0]non-5-ene (DBN) or guanidine systems such as l,5,7-triazabicyclo-[4,4,0]-dec-5-ene, 7-Phenyl-l,5,7-triazabicyclo-[4,4,0]-dec-5-ene, 7-methyl-l,5,7-triazabicyclo-[4,4,0]-dec-5- en, 7,7'-hexylidenedi-l,5,7-triazabi-cyclo-[4,4,0]-dec-5-ene, 7,7'-decylidenedi-l,5,7-triazabicyclo-[4 ,4,0]-dec-5-ene, 7,7'-dodecylidene-di-1,5,7-tri-aza-bicyclo-[4,4,0]-dec-5-ene or phosphazenes such as, for example the phosphazene base Pl-t-Oct = tert. -Octyl -imino-tris-(dimethylamino)-phosphorane, phosphazene base Pl-t-butyl = tert. -Butyl -imino-tris-(dimethylamino)-phosphorane, BEMP = 2-tert.-Butylimino-2-diethylamino-1,3-dimethyl-perhydro-1,3,2-diaza-2-phos-phoran, in question .

Phosphonium catalysts of the formula (VIII) are particularly suitable:

where Ra, Rb, Rc and Rd are the same or different Cl-C10 alkyls, C6-C14 aryls, C7-C15 arylalkyls or C5-C6 cycloalkyls, preferably methyl or C6-C14 aryls, particularly preferably methyl or phenyl can, and Arylalkyl or C5-C6-cycloalkyl, preferably phenyl.

Particularly preferred catalysts are tetraphenylphosphonium chloride, tetraphenylphosphonium hydroxide and tetraphenylphosphonium phenolate; Tetraphenylphosphonium phenolate is very particularly preferred. Tetrabutylphosphonium acetate is also preferred. These catalysts are preferably used in amounts of 10' ² to 10' ⁸ mol, based on 1 mol of the polyester carbonate prepolymer. The amounts of alkaline salts used as co-catalyst can be in the range from 1 to 500 ppb, preferably 5 to 300 ppb and particularly preferably 5 to 200 ppb.

Process step (iii) is preferably carried out at temperatures of 280°C to 400°C, preferably 300°C to 390°C, particularly preferably 305°C to 350°C and further preferably 310°C to 340°C. carried out. It is also preferred that process step (iii) is carried out at a pressure of 0.001 mbar to 50 mbar, particularly preferably 0.005 to 40 mbar, very particularly preferably 0.02 to 30 mbar and further preferably 0.03 to 5 mbar becomes. It is also preferred that no vacuum is applied in process step (iii). It is particularly preferred that process step (iii) is carried out at the above-mentioned temperatures in combination with the above-mentioned pressures. In particular, it is preferred that the components in process steps (i) and (ii) are initially present as a solid. In process step (iii) they are preferably transferred into the melt via an increasing temperature profile. The temperatures mentioned above are preferably the final temperatures. The mixing in process step (iii) preferably takes place at this temperature.

The mixing of the components in the molten state in process step (iii) can be achieved in a manner known to those skilled in the art. A distinction must be made as to whether a reaction of the components is explicitly desired or whether a mixing should take place. However, according to the invention, it cannot be ruled out that even in the latter case a reaction can occur between the components. The mixing is preferably achieved by laminar mixing of the components present in the molten state.

For process step (iii), it is preferred to use reactors which are suitable for the processing of highly viscous masses, which provide sufficient residence time with good mixing and which expose the polyester carbonate prepolymers and the polycarbonates to the desired vacuum, if necessary. According to the invention, extruders, in particular twin-screw extruders or thin-film evaporators, are preferably used for process step (iii). Thin-film evaporators that are fundamentally suitable for carrying out the method according to the invention are, for example, in EP3318311A1, EP1792643A1, DE19535817A1, DE102012103749A1, DE2011493A1 or DD-226778B1 or in publication [1] “Platzer (ed.): Polymerization Kinetics and Technology, Advances in Chemistry; American Chemical Society: Washington, DC, 1973, pages 51 to 67: Fritz Widmer: Behavior of Viscous Polymers during Solvent Stripping or Reaction in an Agitated Thin Film; Swiss Federal Institute of Technology, Zurich, Switzerland”, whereby the one in DE19535817A1, the DD-226778B1 or the one in the EP3318311A1 or the one in [1], Fig. 7, page 58, and Fig. 9, page 60, disclosed thin film evaporator is particularly suitable for carrying out the method according to the invention. Furthermore, according to the invention, reactors according to EP460466A1, EP528210A1, EP638354A1, EP715881A2, EP715882A2, EP798093A2 can also be used or those according to EP329092A1, according to EP517068A1, or EP1436073A1 as well as those according to EP222599A2 can be used.

The time for which the components are mixed in process step (iii) depends, in a manner known to those skilled in the art, on the reactor(s) used. In principle, short times are preferred.

Process step (iii) can be carried out without the presence of at least one stabilizer. However, it has proven to be advantageous if at least one stabilizer is present in process step (iii). Likewise, process step c) can also be carried out in the presence of at least one stabilizer. If at least one stabilizer is used in both process step c) and process step (iii), it can be the same or different in both process steps.

Such a stabilizer is also often referred to as a stabilizing additive. These stabilizing additives, which can be used in the present invention, primarily serve to suppress the transesterification reactions between the individual oligomers or polymers. However, this may also lead to a suppression of the actual reaction of the oligomers or polymers with one another. The suitability of a particular compound for use as a stabilizer in the sense of the present invention and the determination of the suitable amount of such a stabilizer in the sense of the invention can be determined by preparing a mixture of the polyester carbonate blend and the additive and determining the effect on melt viscosity, relative solution viscosity and/or transesterification activity. If one considers the embodiment in which vacuum is applied in process step (iii), a compound is particularly suitable as a stabilizer in the sense of the present invention, the lower the increase in molecular weight (for example measured via the relative solution viscosity). If no vacuum is applied in process step (iii), a compound is particularly suitable as a stabilizer in the sense of the present invention, the lower the molecular weight reduction is (for example measured via the relative solution viscosity). The transesterification activity of a compound can be determined by measuring a ¹³ C NMR spectrum and comparing the different ester bands (see also the process description in the example section). The more carbon atoms there are, as marked with an arrow in formula (la), the more effective the compound examined is, in particular as a stabilizer in the sense of the present invention. In particular, Brönstedt acids are used here. Specific examples of useful Brönsted acid compounds include phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, polyphosphoric acid, boric acid, hydrochloric acid, hydrobromic acid, sulfuric acid, sulfurous acid, adipic acid, azelaic acid, dodecanoic acid, L-ascorbic acid, aspartic acid, benzoic acid, formic acid, acetic acid , citric acid, glutamic acid, salicylic acid, nicotic acid, fumaric acid, maleic acid, oxalic acid, benzenesulfmic acid, toluenesulfmic acid and sulfonic acids such as benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, naphthalenesulfonic acid, sulfonated polystyrene and methyl acrylate-sulfonated styrene copolymer. Particularly preferred are phosphoric acid, phosphorous acid, their salts and esters. Examples of preferred salts are hydrogen phosphates such as zinc or calcium hydrogen phosphates. These are preferably used in amounts of 0.0001 to 0.1, in particular 0.0001 to 0.05% by weight, based on the total composition. These acid compounds can be used either individually or in combination. It is also possible for the acids, esters and salts to be used in the form of a masterbatch based on polycarbonate or polyester or polyester carbonate.

Epoxy compounds which have at least one epoxy group in the molecule can also be used as stabilizers. These can be used in amounts of 0.001% by weight to 0.5% by weight, preferably 0.005 to 0.2% by weight, based on the total weight of all components used. Specific examples of useful epoxy compounds as mentioned above include epoxidized soybean oil, epoxidized linseed oil, phenyl glycidyl ether, allyl glycidyl ether, t-butylphenyl glycidyl ether, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3,4- Epoxy-6-methylcyclohexanecarboxylate, 2,3-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 4-(3,4-epoxy-5-methylcyclohexyl)butyl3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylethylene oxide,

Cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexyhnethyl-6-methylcyclohexanecarboxylate, bisphenol A diglycidyl ether, tetrabromobisphenol A glycidyl ether, diglycidyl ester of phthalic acid, diglycidyl ester of hexahydrophthalic acid, bis-epoxydicyclopentadienyl ether, bis-epoxyethylene glycol, Bis-epoxycyclohexyl adipate, butadiene diepoxide, tetraphenylethylene epoxide, octyl epoxy phthalate, epoxidized polytutadiene, 3,4-dimethyl-l,2-epoxychlorohexane, 3-methyl-5-t-butyl-l, 2-epoxycyclohexane, octadecyl-2,2-dimethyl- 3, 4-epoxycyclohexanecarboxylate, n-butyl-2,2-dimethyl-3, 4-epoxycyclohexanecarboxylate, cyclohexyl-2-methyl-3,4-epoxycyclohexanecarboxylate, n-butyl-2-isopropyl-3,4-epoxy-5- methylcyclohexanecarboxylate, octadecyl-3,4-epoxy;cyclohexanecarboxylate, 2-ethylhexyl-3', 4'-epoxycyclohexanecarboxylate, 4,6-dimethyl-2,3-epoxycyclohexyl-3',4'epoxycyclohexanecarboxylate, 4,5-epoxytetrahydrophthalic anhydride, 3 -t-Butyl-4,5-epoxytetrahydrophthalic anhydride, diethyl-4,5-epoxy-cis-l,2-cyclohexanedicarboxylate and di-n-butyl-3-t-butyl-4,5-epoxy-cis-l,2 - cyclohexanedicarboxylate; These epoxy compounds can be used either individually or in a mixture be used. These epoxy compounds can also be used together with the acid compounds mentioned above.

Furthermore, for example, alkyl phosphates, e.g. B. mono-, di- and trihexyl phosphate, triisoctyl phosphate and trinonyl phosphate can be used as a stabilizer. The preferred alkyl phosphate used is triisooctyl phosphate (tris-2-ethyl-hexyl phosphate). Mixtures of different mono-, di- and trialkyl phosphates can also be used. These can be used in amounts of 0.001 to 0.1% by weight, preferably 0.005 to 0.05% by weight, based on the total weight of all components used.

Likewise, at least one further additive can also be present during process step (iii) and/or process step c) (which differs from the stabilizer described above, which may be present). Such additives, as are usually added to polycarbonates, are in particular thermal or processing stabilizers, antioxidants, in particular phenolic antioxidants, mold release agents, flame retardants, anti-dripping agents, UV absorbers, IR absorbers, antistatic agents, optical brighteners, fillers, light scattering agents, hydrolysis stabilizers and / or additives for laser marking, especially in the usual amounts for polycarbonate-based compositions. Such additives are described, for example, in EP 0 839 623 Al, WO 96/15102 Al, EP 0 500 496 Al or in the “Plastics Additives Handbook”, Hans Doubt, 5th Edition 2000, Hanser Verlag, Munich. These additives can be added individually or in a mixture.

For example, phosphites and phosphonites as well as phosphines can be used as thermal or processing stabilizers. Examples are triphenyl phosphite, diphenyl alkyl phosphite, phenyldialkyl phosphite, tris(nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl phosphite, distearylpentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite,

Diisodecylpentaerythritol diphosphite, Bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, Bis(2,4-di-cumylphenyl)pentaerythritol diphosphite, Bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, Diisodecyloxypentaerythritol diphosphite, Bis (2,4-di-tert-butyl-6-methylphenyl)-pentaerythritol diphosphite, bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphosphite, tristea-rylsorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl) -4,4'-biphenylene diphosphonite, 6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H- dibenz[d,g]-l,3,2-dioxaphosphocin, bis(2,4- di-tert-butyl-6-methylphenyl)methyl phosphite, bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite, 6-fluoro-2,4,8,10-tetra-tert-butyl-12- methyl-dibenz[d,g]-l,3,2-dioxaphosphocin, 2,2',2"-nitrilo-[triethyltris(3,3',5,5'-tetra-tert-butyl-l,r- biphenyl-2,2'-diyl) phosphite], 2-ethylhexyl (3,3',5,5'-tetra-tert-butyl-l,r-biphenyl-2,2'-diyl) phosphite, 5-butyl -5-ethyl-2-(2,4,6-tri-tert-butylphenoxy)-1,3,2-dioxaphosphiran, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, triphenylphosphine (TPP), trialkylphenylphosphine, Bisdiphenylphosphino-ethane or a trinaphthylphosphine. Particular preference is given to using triphenylphosphine (TPP), Irgafos® 168 (tris(2,4-di-tert-butyl-phenyl) phosphite) and tris(nonylphenyl) phosphite or mixtures thereof.

Preferred phenolic antioxidants include alkylated monophenols, alkylated thioalkylphenols, hydroquinones and alkylated hydroquinones. Particularly preferred are Irganox® 1010 (pentaerythritol 3-(4-hydroxy-3,5-di-tert-butylphenyl) propionate; CAS: 6683-19-8) and Irganox 1076® (2,6-di-tert-butyl -4-(octadecanoxycarbonylethyl)~phenol) is used.

These thermal or processing stabilizers and/or phenolic antioxidants can be used in amounts of 0.5 to 0.001% by weight, based on the total weight of all components present. These can be used individually or as mixtures with the above-mentioned additives. They can be added directly or as a masterbatch.

The method according to the invention for producing a polyestercarbonate blend thus delivers a polyestercarbonate blend, which is either a physical mixture and/or a reaction product from the polyestercarbonate prepolymer and the polycarbonate. Therefore, according to the invention, a polyestercarbonate blend is also provided, which was obtained by the method according to the invention for producing a polyestercarbonate blend, preferably in the above-mentioned embodiments or all combinations of preferences.

In a further aspect of the present invention there is provided a polyester carbonate blend comprising

(A) Ester groups of the formula (la)

(B) Carbonate groups of the formula (II)

in the

R6 and R7 each independently represent hydrogen, Ci-Cis-alkyl, Ci-Cis-alkoxy, halogen or each optionally substituted aryl or aralkyl, preferably hydrogen, and

X for a single binding, -o-, -o, -s-, ci to c ₍ ,-alkylene. C2- to CS alkylidi, c to cio-cycloalkyliden or for CE to CI2 arylene, which if necessary with aromatic rings containing further heteroatoms can be fused, preferably for a single bond, C2 to Cs alkylidene or C ₍ , to Cio-cycloalkylidene, particularly preferably isopropylidene,

where in these formulas (IV) to (VI) R ³ each represents Ci-C4-alkyl, aralkyl or aryl, preferably methyl or phenyl, very particularly preferably methyl, and the “*” each indicate the positions with which the formulas (III), (IV), (V) or (VI) attach to the carbonate group in formula (II), m indicates the average number of repeating units and each indicates the positions with which the carbonate groups are incorporated into the polyester carbonate blend are, wherein at least some of the ester groups (A) are directly linked to one another with at least some of the carbonate groups (B) via the formula (VII), where

(VII), in which Y has the meanings described above for (B) and (A) stands for the attachment to the ester group (A) and (B) stands for the attachment to the carbonate group (B), whereby the polyester carbonate blend a relative solution viscosity of at least 1.19 to at most 1.40, preferably 1.20 to 1.38, particularly preferably 1.21 to 1.35 and very particularly preferably 1.22 to 1.33, characterized in that the Polyester carbonate blend contains more mol% of carbon atoms, as marked with an arrow in formula (la), than mol% of carbon atoms, as marked with an arrow in formula (VII),

(la), where Ri, n and “*” are the above

have meanings and

(VII), where (A), Y and (B) have the meanings given above.

Like the polyester carbonate prepolymer, the polyester carbonate blend according to the invention is also characterized by the fact that the isophthalic acid/terephthalic acid is linked to the repeating unit of the polycarbonate (possibly also oligocarbonate, for example from unreacted residues of process step (c) or by reaction in process step (c)) is present via an ester (see formula (VII). Formula (VII) is explained in more detail above by formula (7).

The presence of a structure of formula (VII) can be determined via NMR. An example of this is a direct linkage of bisphenol units to isophthalic acid and/or terephthalic acid units. The link is an ester link. The existence of this connection can be determined via ¹³ C-NMR spectroscopy can be determined by determining the chemical shift of the carbonyl carbon atom marked with an arrow in formula (Vila).

(Vila).

In the experimental part, the synthesis of a model compound from bisphenol A and isophthalic acid/terephthalic acid is described as an example in order to find out/calibrate the position of the carbon marked with the arrow in the formula (Vila) in the ¹³ C NMR.

Polyester carbonates produced using the phase interface process, which include the ester groups (A) and (B), do not have the structural formula (VII) (see Figure 2). In such reactions, an OH-terminated oligoester reacts with a bisphenol (usually bisphenol A) or a corresponding oligocarbonate by reacting with phosgene to form a carbonate. This means that, for example, a resorcinol unit is always linked directly to a BPA unit via a carbonate group. The same applies to the polyester carbonate of DE60212172T2.

The carbon atom, which is marked with an arrow in formula (VII) above, can be formed either by reaction of the chain end of the oligoester with an oligocarbonate and/or polycarbonate in process step (c) and/or (iii). However, it can also be formed by transesterification reactions in process step (c) and/or (iii). Such a transesterification reaction is essentially undesirable because it reduces the intrinsic UV absorbency of the polymer. There must be a certain block length of these esters so that the resulting product has intrinsic weather stability. Nevertheless, the polyester carbonate blend according to the invention always has certain detectable proportions of these carbon atoms. It will be apparent to those skilled in the art that formula (VII) was shown above once with and once without an arrow. For better understanding, the formula (VII) with arrow can also be referred to as formula (VIIx). Therefore, according to the invention, it is essential that there are more mol% of carbon atoms, as marked with an arrow in formula (la), in the polyester carbonate blend than mol% of carbon atoms, as marked with an arrow in formula (VII). It will be apparent to those skilled in the art that formula (la) was shown above once with and once without an arrow. For better understanding, the formula (la) with an arrow can also be referred to as the formula (lax). The ratio of the different ester compounds to one another can ensure that the resulting polyester carbonate blend has both good mechanical properties and intrinsic weather stability.

The ratio of the mol% of the carbon atoms marked in the formulas (lax) and (VIIx) can preferably be determined via ¹³ C NMR spectroscopy. This is preferred Polyester carbonate blend dissolved in CDCI. Tetramethylsilane is more preferably used as a standard. It has been shown that a 600 MHz NMR spectrometer is sufficient to distinguish the individual carbon signals of the formula (lax) and (VIIx). The chemical shift of the carbon signal of formula (VIIx) depends on the repeating unit of the oligo- and/or polycarbonate. If a bisphenol A based oligocarbonate and/or polycarbonate is used, the corresponding signal can be found at approx. 164-165 ppm (see also experimental section). The carbon atom marked in formula (lax) is typically found at a chemical shift of 163-164 ppm when the diol of formula (3) is resorcinol. In order to determine the ratio dermol% of the carbon atoms, the area under the signals is integrated and related to each other. This is a process known to those skilled in the art.

It will be apparent to those skilled in the art that the ester groups (A) and the carbonate groups (B) can each occur multiple times in a polyester carbonate blend. It can also be seen that n and m as well as the number of ester groups (A) and/or carbonate groups (B) must be chosen so that the corresponding solution viscosity of the polyester carbonate blend results. Conversely, the person skilled in the art is able to go from a solution viscosity to a number-average molecular weight. It is also obvious to the person skilled in the art to conclude that n or m is based on such a number-average molecular weight and the proportion of ester groups (A) and/or carbonate groups (B). In particular, the person skilled in the art can also estimate the magnitude of the average number of repetition units n and/or m based on the starting substances. The person skilled in the art is able to assess possible effects on n and/or m through reactions in process step (iii). The m in formula (II) is preferably at least 5, preferably 8 to 300, particularly preferably 10 to 250 and very particularly preferably 25 to 200. It is preferred that the polyester carbonate blend according to the invention has a ratio of 5 to 25% by weight. , particularly preferably 8 to 23% by weight and very particularly preferably 10 to 20% by weight of ester groups (A) in relation to the total weight of the ester groups (A) and the carbonate groups (B). It is also preferred that the polyester carbonate according to the invention consists of at least 80% by weight, particularly preferably at least 90% by weight and very particularly preferably at least 95% by weight of the units of the formula (la) and (II). .

As will be apparent to those skilled in the art, the term “blend” is preferably to be understood at this point to mean that the polyester carbonate according to the invention comprises a mixture of different polymers. These can be polyester carbonates, but also pure polycarbonates. This becomes particularly evident when the polyestercarbonate blend according to the invention is produced by the process according to the invention for producing a polyestercarbonate blend. The polyestercarbonate blend according to the invention preferably additionally comprises a component (X), which is a is polycarbonate. This is particularly preferably a polycarbonate with repeating units of the formula (II), as explained in more detail above. The person skilled in the art is in particular able to transfer the statements regarding the method according to the invention for producing a polyestercarbonate blend to the polyestercarbonate blend according to the invention.

Furthermore, the polyester carbonate blend according to the invention preferably does not contain any methyl 2-hydroxybenzoate. Traces of such a compound can be detected in the blend, for example by NMR spectroscopy. They can remain in the polyestercarbonate blend if activated carbonate sources (e.g. polycarbonates with end groups of formula (301)) are used to prepare the polyestercarbonate blend. Likewise, the polyester carbonate blend according to the invention preferably does not have any end group of the formula (301).

It is preferred that the polyestercarbonate blend according to the invention is characterized in that the polyestercarbonate blend has a relative solution viscosity of at least 1.19 to at most 1.40, preferably 1.20 to 1.38, particularly preferably 1.21 to 1. 35 and most preferably 1.22 to 1.33. This relative solution viscosity ensures that the polyester carbonate blend can be easily processed, for example by injection molding. This relative solution viscosity also makes it possible to demonstrate good mechanical properties for interesting areas of application such as automotive exteriors. The polyester carbonate blend has high stability and is intrinsically weather-stable.

It is also preferred that the polyester carbonate blend according to the invention has a content of phenolic OH groups in the range from 100 ppm to 1200 ppm, preferably 150 ppm to 1000 ppm, particularly preferably 200 ppm to 800 ppm. Alternatively, it is preferred that the polyester carbonate blend according to the invention has a content of phenolic OH groups in the range from 0 ppm to 500 ppm, preferably greater than 50 ppm to 350 ppm, particularly preferably greater than 80 ppm to 800 ppm. This content of phenolic OH groups is preferably determined using infrared spectroscopy. It can also be determined using ¹ H-NMR. However, the signals can overlap here. It is therefore preferred that the content of phenolic OH groups is determined using infrared spectroscopy. For this purpose, the polyester carbonate blend is preferably dissolved in dichloromethane (2g/50 ml) and determined by evaluating the band at a wave number of 3583 cm' ¹ . The required calibration of the infrared device is known to those skilled in the art.

Both the polyestercarbonate prepolymer according to the invention and the polyestercarbonate blend according to the invention can contain rearrangement structures (for example the Fries rearrangement structures known to those skilled in the art). On the one hand, this can result from the fact that in the Process reactions according to the invention are carried out in the melt. As those skilled in the art know, corresponding structures can form under melt transesterification conditions. In addition, the oligocarbonates and/or polycarbonates used according to the invention can also already have such frieze structures. According to the invention, it has been found that these Fries rearrangement structures do not have a particularly adverse effect on the properties of the polyestercarbonate prepolymer and/or blend according to the invention.

In particular, the polyestercarbonate prepolymer according to the invention and/or the polyestercarbonate blend according to the invention and/or the oligocarbonate and/or polycarbonate to be used can contain at least one, preferably several, of the following structures (4y) to (7y):

in which the phenyl rings can be independently substituted once or twice with Cl - C8 alkyl, halogen, preferably CI to C4 alkyl, particularly preferably with methyl and X represents a single bond, C 1 to C6 alkylene, C2 to C5 alkylidene or C5 bis C6 cycloalkylidene, preferably a single bond or C1 to C4 alkylene and particularly preferably isopropylidene. The amount of structural units (4y) to (7y) is in total (determined after saponification) generally in the range from 10 ppm to 1000 ppm, preferably greater than 10 ppm to 900 ppm, particularly preferably in the range from 50 to 850 ppm, preferably in the range from 80 to 800 ppm.

In order to determine the amount of rearrangement structures, the respective polymer is subjected to total saponification and the corresponding degradation products of the formulas (4ya) to (7ya) are formed, the amount of which is determined using HPUC. The structures (4ya) to (7ya) are given as examples for the use of a polycarbonate comprising bisphenol A. (This can be done, for example, as follows: The polycarbonate sample is saponified using sodium methylate under reflux. The corresponding solution is acidified and evaporated to dryness. The drying residue is dissolved in acetonitrile and the phenolic compounds of the formula (4ya) to (7ya) using HPUC with UV -detection determined):

The amount of the compound of the formula (4ya) released is preferably 20 to 800 ppm, particularly preferably 25 to 700 ppm and particularly preferably 30 to 500 ppm.

The amount of the compound of formula (5ya) released is preferably 0 (ie below the detection limit of 10 ppm) to 100 ppm, particularly preferably 0 to 80 ppm and particularly preferably 0 to 50 ppm. The amount of the compound of formula (6ya) released is preferably 0 (ie below the detection limit of 10 ppm) to 800 ppm, more preferably 10 to 700 ppm and particularly preferably 20 to 600 ppm and very particularly preferably 30 to 350 ppm.

The amount of compound of formula (7ya) released is preferably 0 (i.e. below the detection limit of 10 ppm) to 300 ppm, preferably 5 to 250 ppm and particularly preferably 10 to 200 ppm.

In a further aspect of the present invention, the polyestercarbonate prepolymer according to the invention is used, preferably in all previously described embodiments and/or combinations of preferences, for compatibilizing an oligoester comprising structures of the formula (I),

in which Ri independently represents a hydrogen atom, a halogen or an alkyl group with 1 to 4 carbon atoms and n is at least 4, with a polycarbonate.

As already described above, it was found according to the invention that the polyestercarbonate prepolymer improves the incorporation of the oligoester groups into a polycarbonate. The result is the single-phase system described above. In addition to the compatibilizing effect, the polyestercarbonate prepolymer can also be bonded to the polycarbonate by a chemical reaction. Preferred definitions in the chemical structures are given below. These preferences apply to the process according to the invention for producing a polyestercarbonate prepolymer, the polyestercarbonate prepolymer according to the invention, the process according to the invention for producing a polyestercarbonate blend, the polyestercarbonate blend and / or the use of the polyestercarbonate prepolymer according to the invention, each independently of one another or simultaneously . It will be apparent to the person skilled in the art that some chemical formulas are related (e.g. formula (I) and formula (la)) or that they can be derived from one another.

According to the invention, it is preferred that Ri in formula (I) and/or (la) represents hydrogen. It is also preferred that Y in formula (II) represents a structure of formula (III). It is further preferred that Ri in formula (I) and/or (la) stands for hydrogen and Y in formula (II) stands for a structure of the formula (III). It is also preferred that R6 and R7 in formula (III) each independently represent hydrogen or Ci-Ci2-alkyl, particularly preferably hydrogen or C'i-Cx-alkyl and very particularly preferably hydrogen or methyl. This applies in particular to the case that Ri in formula (I) and/or (la) represents hydrogen and Y in formula (II) represents a structure of the formula (III).

It is also preferred that X in formula (III) represents isopropylidene. This applies in particular to the case that Ri in formula (I) and/or (la) stands for hydrogen, Y in formula (II) stands for a structure of the formula (III) and R6 and R7 in formula (III) are each independent each other represent hydrogen or Ci-Ci2-alkyl, particularly preferably hydrogen or C'i-Cx-alkyl and very particularly preferably hydrogen or methyl.

It is particularly preferred that Y is introduced into the carbonate group (B) via diphenols which are selected from the group consisting of 4'-dihydroxydiphenyl, 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A) , 2,4-bis-(4-hydroxyphenyl)-2-methylbutane, l,l-bis-(4-hydroxyphenyl)-p-diisopropylbenzene, 2, 2-bis-(3-methyl-4-hydroxyphenyl)-propane , Dimethyl - Bisphenol A, Bis-(3, 5-dimethyl-4-hydroxyphenyl)-methane, 2,2-Bis-(3,5-dimethyl-4-hydroxyphenyl)-propane, Bis-(3,5-dimethyl -4-hydroxyphenyl)-sulfone, 2,4-bis-(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutane, l,l-bis-(3,5-dimethyl-4-hydroxyphenyl)-p- diisopropylbenzene and l,l-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, particularly preferably over bisphenol A.

The polyester carbonate blend according to the invention can be processed as such into all kinds of molded articles. It can also be processed with other thermoplastics and/or polymer additives to form thermoplastic molding compounds, which are then formed into moldings. The shaped bodies are further objects of the present invention. The polymer additives are preferably from the group consisting of flame retardants, anti-dripping agents, flame retardant synergists, smoke inhibitors, lubricants and mold release agents, nucleating agents, antistatic agents, conductivity additives, stabilizers (e.g. hydrolysis and heat aging stabilizers and transesterification inhibitors), flowability promoters, phase compatibilizers, dyes and pigments, impact strength modifiers as well as fillers and reinforcing materials.

The shaped bodies containing the polyestercarbonate blend according to the invention can be produced, for example, by injection molding, extrusion and blow molding processes. Another form of processing is the production of molded parts by deep drawing from previously manufactured panels or foils. Short description of the characters:

Figure 1: Excerpt from the ¹³ C-NMR spectra of comparative example 2 at different reaction times

Figure 2: Excerpt from a ¹³ C-NMR spectrum of a commercial product

Isophthalic acid/terephthalic acid resorcinol ester blocks and BPA, prepared using

Phase interface method

Figure 3: Excerpt from the ¹³ C-NMR spectra of Example 1 according to the invention at different reaction times

Figure 4: schematic representation of the experimental setup of Example 5 according to the invention

Explanation of the reference numbers:

1 twin screw extruder

2 mixing kettles

3.1 Gear pump

3.2 Gear pump

4 static mixers

5 vacuum pump

6 vacuum pump

7 capacitor

8 capacitor

9 water bath

10 strand granulator a to k extruder housing

Figure 5: Schematic representation of the experimental setup of Examples 6 and 7 according to the invention. Explanation of the reference numbers:

1 twin screw extruder

2 differential dosing scales

5 vacuum pump

6 vacuum pump

7 capacitor

8 capacitor

9 water bath

10 strand granulator a to k extruder housing Examples

Used material:

Terephthalic acid: for synthesis, CAS 100-21-0, Bernd Kraft Duisburg

Isophthalic acid: 99%, CAS 121-91-5, Sigma-Aldrich

Resorcinol: 99%, CAS 108-46-3, ABCR

Diphenyl carbonate: 99.5%, CAS 102-09-0; Acres Organics, Geel, Belgium, abbreviated as DPC

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

Tetrabutylphosphonium acetate (TBPAc): CAS-34430-94-9, prepared according to Angewandte Chemie, International Edition, Vol. 48, Issue: 40, 7398-7401; 2009

Sodium benzoate: > 99%, CAS 532-32-1, Sigma-Aldrich

(3',4'-Epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate; CAS: 2386-87-0; Sigma-Aldrich, Munich Germany

ADK Rod PEP 36: 3,9-Bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane; CAS 80693-00-1; ADEKA Europe GmbH 40212 Düsseldorf Germany

Preparation of oligoester 1:

20.77 g (0.125 mol) terephthalic acid, 20.77 g (0.125 mol) isophthalic acid, 30.28 g (0.275 mol) resorcinol, 109.79 g (0.5125 mol) diphenyl carbonate and 0.036 g DMAP (4- Dimethylaminopyridine; 200 ppm based on the starting materials) and 0.054g

Tetrabutylphosphonium acetate (300 ppm), placed in a flask with a short-path separator.

The mixture was freed of oxygen by evacuation four times and aerating with nitrogen. The mixture was melted and heated to 200 ° C under normal pressure with stirring. A suspension was created because the terephthalic acid did not initially dissolve in the melt. The mixture was stirred at this temperature for approximately 3 hours. Carbon dioxide was released. It was slowly heated to 240 °C. Phenol distilled off. The mixture was stirred at 240 °C for about 1 hour. Finally, the mixture was stirred at 260 °C for half an hour. After the evolution of gas had ended, the reaction mixture was cooled to 210 ° C and the pressure was reduced. The pressure was gradually reduced to 60 mbar within 45 minutes. The temperature was raised to 230 °C and stirred at this temperature for half an hour. Then it became Temperature raised to 245 °C. The reaction mixture was stirred for a further 0.5 h and then the pressure was reduced to the technically feasible minimum (approx. 1 mbar). A light brown melt was obtained. The analytical data are summarized in Table 1.

Preparation of oligoester 2:

The synthesis of the oligoester was carried out in principle like that of the oligoester 1.

Deviating from this, 62.31 g (0.375 mol) terephthalic acid, 62.31 g (0.375 mol) isophthalic acid, 86.70 g (0.7875 mol) resorcinol, 329.37 g (1.5375 mol) diphenyl carbonate and 0.216 g DMAP (4-Dimethylaminopyridine; 400 ppm based on the starting materials) and 0.162 g of tetrabutylphosphonium acetate (300 ppm), placed in a flask with a short-path separator.

The maximum temperature was 245°C bath temperature and replaced the 260°C stage with the holding time remaining the same.

The rest of the experiment was carried out analogously to the production of oligoester 1.

Preparation of oligoester 3:

The synthesis of oligoester 3 was carried out in principle like that of oligoester 1.

Deviating from this, 62.31 g (0.375 mol) terephthalic acid, 62.31 g (0.375 mol) isophthalic acid, 107.37 g (0.975 mol) resorcinol, 369.53 g (1.725 mol) diphenyl carbonate and 0.24 g DMAP (4 -Dimethylaminopyridine; 400 ppm based on the starting materials) and 0.18g tetrabutylphosphonium acetate (300 ppm), placed in a flask with a short-path separator.

Table 1

Oligocarbonate: Linear bisphenol A oligocarbonate containing phenyl end groups and phenolic OH end groups with a relative solution viscosity of 1.17 was used as the starting material for the production of the polyester carbonate. This oligocarbonate did not contain any additives such as UV stabilizers, mold release agents or thermal stabilizers. The oligocarbonate was produced using a melt transesterification process as described in WO02085967A1 and was removed directly at the outlet of the first horizontal reactor. The oligocarbonate has a phenolic end group content of 0.16% by weight.

Polycarbonate: linear bisphenol A polycarbonate with phenyl end groups with an MVR of 13 g/20 min according to ISO 1133.

Analytical methods:

Solution viscosity:

Determination of solution viscosity: The relative solution viscosity (prel; also referred to as eta rel) was determined in dichloromethane at a concentration of 5 g/1 at 25 °C using an Ubbeloh deviscometer.

GPC:

The molecular weights were determined using gel permeation chromatography with dichloromethane as eluent. BPA polycarbonate was used as a standard. The signal from the refractive index detector (RID) was used. The corresponding method is defined under No. 2301-0257502-09D of Currenta GmbH & Co. OHG, which can be requested from Currenta at any time.

Determination of the content of phenolic OH end groups:

Using infrared spectroscopy: The polyester carbonate, dissolved in dichloromethane (2g / 50 ml; 1mm quartz cuvette), was analyzed in the Nicolet iS 10 FT infrared spectrometer from Thermo Fisher Scientific. The content of phenolic OH end groups was determined by evaluating the band Wave number 3583 cm" ¹ determined. Using 'H-NMR spectroscopy: The measurement was carried out in dichloromethane with tetramethylsiloxane as an internal standard. The content of OH groups is given in% by weight relative to the oligomer. The signal of the OH was used for evaluation -Group integrated and placed in relation to the signals of the oligomer. Usually the resonance of the OH group of the oligomer is between 5.3 - 5.6 ppm. (However, it is known to those skilled in the art that OH signals in NMR vary depending on conditions such as water content can shift in the solvent)

¹³ C NMR spectroscopy:

The linkage of isophthalic acid and/or terephthalic acid units and bisphenol A (see chemical formula (VIIx)) was demonstrated via ¹³ C-NMR spectroscopy. It is also referred to below as IPS/TPS-BPA ester. The linkage of the isophthalic acid and/or terephthalic acid units and resorcinol was also demonstrated (see chemical formula (lax)). It is also referred to below as IPS-TPS resorcinol ester.

The carbonyl carbon atom of the isophthalic acid and/or terephthalic acid linkage with bisphenol A showed a shift at 164-165 ppm whereas the isophthalic and/or terephthalic acid resorcinol ester showed a signal at approximately 163-164 ppm.

The measurement was carried out on a Bruker Avance III HD 600 MHz NMR spectrometer. The measurement was carried out in CDCI, with tetramethylsilane as a standard. The ratio of the different groups was determined by integrating the corresponding signals (ratio of the areas to each other).

The glass transition temperature (Tg) was determined using dynamic differential calorimetry (DSC) according to the 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 turning point in the second heating process.

Production of a model ester compound from BPA and terephthaL/isophthalic acid

21.9 mmol of BPA and a total of 21.9 mmol of the diphenyl ester from terephthalic acid and isophthalic acid were placed in a multi-neck round tube. 2.4 mg of the tetrabutylphosphonium acetate was added, which corresponded to 0.02% of the total mass. The contents of the flask were freed of oxygen by four times evacuation and inerting with nitrogen. The mixture was heated to 200°C with constant stirring. There was continuous condensation formation. As phenol formation increased, the initially cloudy, liquid mixture became increasingly clear. An orange color appeared, which increased in intensity as the temperature increased to 230°C. About 80 minutes after the start of the reaction, the pressure was reduced to 10 to 100 mbar in order to remove the phenol. The homogeneous, orange-brownish product was removed. ¹³ C NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); IPS/TPS-BPA ester C atom

This substance was prepared to clearly identify the signal of the ester carbon atom, which characterizes the ester of BPA and terephthalic acid or isophthalic acid. It was shown that the corresponding signal is at 164.2 to 164.5 ppm.

Comparative example 1

8g of the oligoester 1 and 32g of the oligocarbonate described above were placed in a multi-necked flask.

The contents of the flask were freed of oxygen by four times evacuation and inerting with nitrogen. The mixture was immersed in a metal bath at a temperature of 300°C. As soon as possible, the melt was homogenized using a stirrer within 15 minutes. The stirring speed was then set to 280-400rpm and the pressure was quickly reduced to the technically possible minimum, which must reach at least <3mbar.

During the course of the experiment, the melt viscosity increased continuously, with condensate being continuously removed. After 10 minutes, the heating bath temperature was increased to 320 ° C under the conditions described. After a further 10 minutes, the heating bath temperature was increased to 335 ° C under the conditions described. After 10 minutes, the highly viscous, transparent, greenish to orange product was removed. ¹³ C NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); high intensity; IPS/TPS-BPA ester C atom; 163.6-163.8 ppm (m, 1C); low intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 3.8: 1)

Comparative Example 1 shows that, under the selected reaction conditions, surprisingly an almost complete transesterification towards the IPS/TPS-BPA ester occurs. The high intensity of the corresponding signal in the ¹³ C NMR spectrum proves this. There is only a small amount of IPS/TPS resorcinol ester left. Comparative example 2

Educt weight: 4g of the oligoester 1 and 36g of the polycarbonate were placed in a multi-necked flask. The driving style was identical to comparative example 1

Sample immediately after melting: cloudy melt

¹³ C-NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); very low intensity; IPS/TPS-BPA ester C-atom; 163.6-163.8 ppm (m, 1C); high intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1: 13)

Sample after 10 minutes: cloudy melt

¹³ C-NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); very low intensity; IPS/TPS-BPA ester C-atom; 163.6-163.8 ppm (m, 1C); high intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1: 10)

Sample after 20 min (after increasing the temperature from 320 to 335 °C): transparent melt

¹³ C NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); high intensity; IPS/TPS-BPA ester C atom; 163.6-163.8 ppm (m, 1C); low intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 6: 1).

Sample after 30 min: transparent melt

¹³ C NMR (xy MHz): 164.2-164.5 ppm (m, 1 C); high intensity; IPS/TPS-BPA ester C atom; 163.6-163.8 ppm (m, 1C); very low intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 10: 1).

The samples after 0 (directly after melting) and after 10 minutes show that practically no transesterification has taken place. The cloudy melt also proves that the aromatic oligoester and the aromatic polycarbonate cannot be mixed transparently, i.e. a phase mixture of two independent polymer phases is formed.

The samples after 20 and 30 minutes, however, demonstrate practically complete transesterification. In this case, the sample melts are transparent; this indicates a uniform polymer phase.

In Comparative Example 1, an oligocarbonate with a relatively high OH end group content was used. This product therefore has a higher reactivity than the high molecular weight polycarbonate (with a lower content of phenolic OH groups) in Comparative Example 2. That's why it was all the more surprising that in this case too it was practically complete Transesterification occurs. The production of a uniform copolymer at low temperatures does not seem possible, since both polymer phases are present next to each other without a reaction occurring. At higher temperatures, however, complete transesterification occurs without any significant amount of IPS-TPS resorcinol ester being present.

The ¹³ C-NMR spectra at the different sampling times are shown in Figure 1.

Comparative example 3

Educt weight: 4g of the oligoester 1 and 36g of the oligocarbonate were placed in a multi-necked flask.

As the process progressed, a significantly increasing melt viscosity and slight condensate separation were observed.

After 30 minutes, the highly viscous, transparent, greenish to orange product was removed.

Sample after 5 minutes:

¹³ C NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); medium intensity; IPS/TPS-BPA ester C atom;

163.6-163.8 ppm (m, 1C); medium - high intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1: 1.7)

Sample after 15 minutes:

¹³ C NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); high intensity; IPS/TPS-BPA ester C atom;

163.6-163.8 ppm (m, 1C); medium - low intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1.7: 1)

Sample after 30 minutes:

163.6-163.8 ppm (m, 1C); low intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 3.8: 1) In this comparative example, it should be checked whether it is possible to produce the desired product with high amounts of IPS-TPS resorcinol ester by lowering the temperature. However, it can be seen that after just 5 minutes there is a significant proportion of BPA ester, which increases further as the reaction progresses. It is therefore doubtful whether the desired product can be produced through targeted temperature control.

Inventive example 1

Educt weight: 8g of the oligoester 2 and 2g of the oligocarbonate were placed in a multi-necked flask.

The contents of the flask were freed of oxygen by four times evacuation and inerting with nitrogen. The mixture was immersed in a metal bath at a temperature of 310°C. As soon as possible, the melt was homogenized using a stirrer within 15 minutes. The stirring speed was then set to 280-400rpm and the pressure was quickly reduced to the technically possible minimum, which must reach at least <3mbar. As the process progressed, a significantly increasing melt viscosity and slight condensate separation were observed.

After 30 minutes, the highly viscous, transparent, greenish to orange product was removed (intermediate samples were taken after 5 and 15 minutes)

Sample after 5 minutes:

¹³ C NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); low intensity; IPS/TPS-BPA ester C atom; 163.6-163.8 ppm (m, 1C); high intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1:3.5)

The signal intensities of sample 15 min and sample 30 min practically did not change compared to sample 5 min.

This shows that in this case it is possible to obtain a high amount of IPS-TPS resorcinol ester. The amount of resorcinol ester does not change significantly during the course of the reaction.

The ¹³ C-NMR spectra at the different sampling times are shown in Figure 2.

Example 2 according to the invention

Educt weight: 8g of the oligoester 3 and 2g of the oligocarbonate were in one

Multi-necked flask presented. The driving style was identical to “Inventive Example 1”.

Sample after 5 minutes: ¹³ C NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); low intensity; IPS/TPS-BPA ester C atom; 163.6-163.8 ppm (m, 1C); high intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1: 11.5).

This shows that it is also possible in this case to obtain a high amount of IPS-TPS resorcinol ester. The amount of resorcinol ester does not change significantly during the course of the reaction.

Inventive example 3

Educt weight: 1.875 g from the product of the experiment described in Example 1 according to the invention and 13.125 g of the polycarbonate were placed in a multi-necked flask so that a mass fraction of the oligoester of 10% was achieved. There were 7.5 mg of 3', 4'-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate and 15 mg of ADK rod. PEP-36 added. The contents of the flask were freed of oxygen by blanketing with nitrogen for 10 minutes. The mixture was immersed in a metal bath at a temperature of 300°C. As soon as possible, the melt was homogenized using a stirrer within 15 minutes. A sample (0 min.) was then taken. Now the stirring speed was set to 280-400rpm and the pressure was quickly reduced to the technically possible minimum, which must reach at least <3mbar. As the process progressed, a significantly increasing melt viscosity and slight condensate separation were observed.

Sample after 0 min (after melting):

¹³ C NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); low intensity; IPS/TPS-BPA ester C atom; 163.6-163.8 ppm (m, 1C); high intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1:3)

Sample after 5 minutes:

¹³ C NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); low - medium intensity; IPS/TPS-BPA ester C atom; 163.6-163.8 ppm (m, 1C); high intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1:2).

Sample after 15 minutes: ¹³ C NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); medium intensity; IPS/TPS-BPA ester C atom;

163.6-163.8 ppm (m, 1C); medium - high intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1: 1.4).

Sample after 30 minutes:

163.6-163.8 ppm (m, 1C); medium intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1: 1). The eta rel of this sample was 1.309.

The ¹³ C-NMR spectra show that only after 30 minutes of reaction time does the proportion of IPS/TPS-BPA ester approximately equal to the proportion of IPS-TPS-resorcinol ester. Up to a reaction time of 15 minutes, the proportion of IPS-TPS resorcinol ester clearly predominates. This example surprisingly shows, compared to the comparative examples, that the melt transesterifies relatively slowly. Even if the proportion of BPA polycarbonate is high, surprisingly only a small proportion transesterifies to the IPS/TPS-BPA ester.

Inventive example 4

Educt weight: 1.875 g from the product of the experiment described in Example 2 according to the invention and 13.125 g of the polycarbonate were placed in a multi-necked flask so that a mass fraction of the oligoester of 10% was achieved. There were 7.5 mg of 3', 4'-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate and 15 mg of ADK rod. PEP-36 added. The driving style was identical to “Inventive Example 3”.

Sample after 0 min (after melting):

¹³ C NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); low intensity; IPS/TPS-BPA ester C atom;

163.6-163.8 ppm (m, 1C); high intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1:4.3).

Sample after 5 minutes:

163.6-163.8 ppm (m, 1C); high intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1:4)

Sample after 15 minutes:

163.6-163.8 ppm (m, 1C); high intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1:2.5)

Sample after 30 minutes: ¹³ C NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); low - medium intensity; IPS/TPS-BPA ester C atom; 163.6-163.8 ppm (m, 1C); medium intensity; IPS-TPS resorcinol ester carbon atom (ratio approx. 1:2.1)

In this example the tendency to transesterification is even lower. Even after 30 minutes, the proportion of IPS-TPS resorcinol ester surprisingly predominates.

Inventive example 5

For example 5 according to the invention, the experimental setup shown schematically in FIG. 4 was used.

830.7 g (5.0 mol) of terephthalic acid, 830.7 g (5.0 mol) of isophthalic acid, 1156.05 g of resorcinol and 4284.4 g (20.0 mol) of diphenyl carbonate were placed in a stirred tank (2). Further, 2.84 g of dimethylaminopyridine and 2.13 g of tetrabutylphosphonium acetate were added to the reaction mixture. The boiler was freed of oxygen by repeated evacuation and inerting with nitrogen. The reaction mixture was melted under normal pressure and the liquid reaction mixture was conveyed back into the stirred tank (2) via the static mixer (4) using the gear pump (3.1). The temperature of the boiler was gradually increased to 245 °C. Carbon dioxide was released and removed from the reaction vessel. After the evolution of carbon dioxide had ended and the reaction mixture became clear, the kettle was cooled to 210 ° C and the pressure was gradually reduced to 60 mbar within 30 minutes. Phenol was continuously removed from the reaction mixture. There was a holding phase of 30 minutes. The temperature was then increased to 230 ° C and kept constant for a further 30 minutes. The temperature was then increased to 245°C and kept constant for a further 30 min. The best possible vacuum was then applied (<1 mbar) and maintained under the conditions described for a further 30 minutes.

The reactor (2) was cooled and 600.6 g of oligocarbonate were added to the reaction mixture. The mixture was melted at 250 °C and the pressure was gradually reduced to <1 mbar. The melt was stirred with a reversible stirrer at 17.5 rpm and conveyed with the gear pump (3.1) through the circuit line with the static mixer (4). The melt was conveyed in a circle in this way for 75 minutes. The polymer melt was then continuously conveyed to the twin-screw extruder (1) (type ZSE 27 MAXX with 11 housings) by a second gear pump (3.2) at a throughput of 1.2 kg/h Leistritz Extrusionstechnik GmbH, Nuremberg). The extruder housings are designated in Figure 4 with the letters “a” to “k”. The extruder was operated at 100 rpm at a housing temperature of 310 ° C. The melt was fed into the fourth housing (d) of the extruder. Reverse degassing with 25 mbar absolute pressure took place via the first housing (a) of the extruder (a). On the 5th A vacuum of 25 mbara was applied to the housing of the extruder (e) and a vacuum of 3-5 mbara was applied to the housings (g), (i) and (j). The polymer melt was extruded at a melt temperature of 311 ° C, passed into a water bath (9) and granulated using a strand granulator (10). The polymer sample had an Mn of 3750 g/mol and an Mw of 8300 g/mol (RID).

Inventive example 6

The experimental setup for Example 6 according to the invention is shown in Figure 5.

468.75 g of the granulated product from Example 5 according to the invention, 3281.25 g of polycarbonate and 1.875 g of epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate and 3.750 g of ADK rod PEP 36 were mixed in a wheel mixer for 30 minutes.

The mixture was continuously fed into the feed housing (a) of the twin-screw extruder (1) via the differential metering scale (2) at a throughput of 2 kg/h (type ZSE 27 MAXX with 11 housings from Leistritz Extrusionstechnik GmbH, Nuremberg) and at 150 rpm extruded. The extruder housings are designated in Figure 5 with the letters “a” to “k”. The mixture was at a housing temperature of 160°C for housing (b), 240°C for housing (c), 300°C for housing (d) and 320°C for housings (f) to (k) with a Melt temperature of 329 ° C, passed into the water bath (9) and granulated with the strand granulator (10). The extruder has degassing zones on the housings (e), (g), (i) and (j). These were operated under normal pressure.

The product has the following analytical data: transparent granules, Eta rel: 1.225, Tg: 143 °C, the ¹³ C spectrum predominantly shows IPS-TPS resorcinol ester (ratio approx. 1:2.6).

Inventive example 7

The experimental setup for Example 7 according to the invention is shown in Figure 5.

The mixture from example 6 according to the invention was continuously fed into the feed housing (a) of the twin-screw extruder (1) via the differential metering scale (2) at a throughput of 1.4 kg/h (type ZSE 27 MAXX with 11 housings from Leistritz Extrusionstechnik). GmbH, Nuremberg) and extruded at 100 rpm. The extruder housings are designated in Figure 5 with the letters “a” to “k”. The mixture was at a housing temperature of 160°C for housing (b), 240°C for housing (c), 300°C for housing (d) and 320°C for housings (f) to (k) with a Melt temperature of 328 ° C is extruded, passed into the water bath (9) and granulated with the strand granulator (10). A vacuum of 32 mbar was applied to housing (e) of the extruder and a vacuum of <1 mbar was applied to housing (g), (i) and (j). The product has the following analytical data: transparent granules, eta rel: 1.230, Tg: 145 °C, the ¹³ C spectrum predominantly shows IPS-TPS resorcinol ester (ratio approx. 1:2.6).

The extrusion tests show that it is possible to use the process according to the invention to produce the desired polyester carbonate, which still contains a high level of the desired resorcinol ester linkages.

Claims

Patent claims:

1. A process for producing a polyestercarbonate prepolymer, comprising the steps

(a) providing an oligoester comprising structures of the formula (I),

(b) providing an oligocarbonate and/or a polycarbonate and

(c) reacting 65 to 95% by weight of the oligoester from step (a) with 35 to 5% by weight of the oligocarbonate and / or polycarbonate from step (b), the% by weight being the sum of Weight of oligoester from step (a) and of oligocarbonate and / or polycarbonate from step (b), by means of a condensation reaction in the melt to obtain a polyestercarbonate prepolymer.

2. The method according to claim 1, characterized in that the oligoester of step (a) has a number-average molecular weight Mn of 500 g/mol to 8000 g/mol, preferably 600 g/mol to 5000 g/mol and particularly preferably 700 g/mol up to 3000 g/mol.

3. The method according to any one of claims 1 or 2, characterized in that the oligocarbonate of step (b) has a relative solution viscosity of 1.08 to 1.22, preferably 1.11 to 1.22, particularly preferably 1.13 to 1 .20.

4. The method according to any one of claims 1 to 3, characterized in that step (c) is carried out at a pressure reduced in relation to the ambient pressure.

5. Polyestercarbonate prepolymer comprising

(A) Ester groups of the formula (la)

in which Ri independently represents a hydrogen atom, a halogen or an alkyl group with 1 to 4 carbon atoms, n is at least 4 and the “*” indicate the positions with which the ester groups are integrated into the polyester carbonate blend,

(B) Carbonate groups of the formula (II)

in the

X for a single binding, -o-, -o, -s-, ci to c ₍ ,-alkylene. C2 to CS alkylidi, c to cio-cycloalkyliden or for CE to CI2 arylene, which if necessary with aromatic rings containing further heteroatoms can be fused,

(IV) (V) (VI), where in these formulas (IV) to (VI) R ³ each represents Ci-C4-alkyl, aralkyl or aryl, preferably methyl or phenyl, very particularly preferably methyl, and the "*" indicates the positions with which the formulas (III), (IV), (V) or (VI) attach to the carbonate group in formula (II), m indicates the average number of repeating units and which indicate the positions in each case , with which the carbonate groups are integrated into the polyester carbonate blend, wherein at least some of the ester groups (A) are directly linked to one another with at least some of the carbonate groups (B) via the formula (VII), where

(VII), in which Y has the meanings described above for (B) and (A) stands for the attachment to the ester group (A) and (B) stands for the attachment to the carbonate group (B), characterized in that Polyester carbonate prepolymer contains more mol% of carbon atoms, as marked with an arrow in formula (la), than mol% of carbon atoms, as marked with an arrow in formula (VII),

have.

6. Process for producing a polyestercarbonate blend, comprising the steps

(i) providing a polyestercarbonate prepolymer according to claim 5 or produced by the method according to one of claims 1 to 4,

(ii) providing a polycarbonate with a weight average molecular weight Mw of 24,000 g/mol to 40,000 g/mol, determined by gel permeation chromatography, calibrated against bisphenol A polycarbonate standards using dichloromethane as eluent,

(iii) converting the polyestercarbonate prepolymer from step (i) and the polycarbonate from step (ii) into a molten state and mixing in the molten state 5 to 25% by weight of the polyestercarbonate prepolymer with 95 to 75% by weight of polycarbonate, wherein the weight percent refers to the sum of the weight of polyestercarbonate prepolymer from step (i) and polycarbonate from step (ii) to obtain a polyestercarbonate blend.

7. The method according to claim 6, characterized in that at least one stabilizer is present in process step (iii).

8. The method according to any one of claims 6 or 7, characterized in that process step (iii) is carried out at a pressure reduced in relation to the ambient pressure.

9. Polyester carbonate blend comprising

(A) Ester groups of the formula (la)

(B) Carbonate groups of the formula (II)

in the

R6 and R7 each independently represent hydrogen, Ci-Cis-alkyl, Ci-Cis-alkoxy, halogen or optionally substituted aryl or aralkyl, and X for a single binding, -o-, -o, -s-, ci to c ₍ ,-alkylene. C2 to CS alkylidi, c to cio-cycloalkyliden or for CE to CI2 arylene, which if necessary with aromatic rings containing further heteroatoms can be fused,

(IV) (V) (VI), where in these formulas (IV) to (VI) R ³ each represents Ci-C4-alkyl, aralkyl or aryl, preferably methyl or phenyl, very particularly preferably methyl, and the "*" indicates the positions with which the formulas (III), (IV), (V) or (VI) attach to the carbonate group in formula (II), m indicates the average number of repeating units and which indicate the positions in each case , with which the carbonate groups are incorporated into the polyester carbonate blend, at least some of the ester groups (A) being directly linked to one another with at least some of the carbonate groups (B) via the formula (VII), where

(VII), in which Y has the meanings described above for (B) and (A) stands for the attachment to the ester group (A) and (B) stands for the attachment to the carbonate group (B), whereby the polyester carbonate blend has a relative solution viscosity of at least 1.21 to at most 1.38, characterized in that the polyester carbonate blend contains more mol% of carbon atoms, as marked with an arrow in formula (la), than mol% of carbon atoms, such as marked with an arrow in formula (VII),

(la), where Ri, n and “*” are the above

have meanings and

where (A), Y and (B) have the meanings given above.

10. Polyestercarbonate blend according to claim 9, characterized in that the polyestercarbonate blend has a content of phenolic OH groups in the range of greater than 0 ppm and less than or equal to 500 ppm.

11. Use of the polyestercarbonate prepolymer according to claim 5 or produced by the process according to one of claims 1 to 4 for compatibilizing an oligoester comprising structures of the formula (I),

12. A process for producing a polyestercarbonate prepolymer according to one of claims 1 to 4, polyestercarbonate prepolymer according to claim 5, process for producing a polyestercarbonate blend according to one of claims 6 to 8, polyestercarbonate blend according to one of claims 9 or 10 or Use according to claim 11, characterized in that Ri in formula (I) or formula (la) represents hydrogen.

13. A process for producing a polyestercarbonate blend according to one of claims 6 to 8 or 12 or polyestercarbonate blend according to one of claims 9 to 10 or 12, characterized in that Y in formula (II) represents a structure of formula (III) stands . Process for producing a polyestercarbonate blend according to one of claims 6 to 8 or 12 to 13 or polyestercarbonate blend according to one of claims 9 to 10 or 12 to 13, characterized in that R6 and R7 in formula (III) are each independent of one another represents hydrogen or Ci-Cn-alkyl, particularly preferably hydrogen or C'i-Cx-alkyl and very particularly preferably hydrogen or methyl. Shaped body comprising the polyestercarbonate blend according to one of claims 9 to 10 or 12 to 14.