Polyester carbonate blend and its production via a polyester carbonate prepolymer

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

[0001] POLYESTERCARBONATE BLEND AND ITS PRODUCTION VIA A

[0002] POLYESTERCARBONATE PREPOLYMER

[0003] The present invention relates to a process for producing a polyester carbonate prepolymer, a polyester carbonate prepolymer, a process for producing a polyester carbonate blend using the polyester carbonate prepolymer, a polyester carbonate blend and a use of the polyester carbonate prepolymer.

[0004] Polyester carbonates, which contain ester blocks of iso- and / or terephthalic acid and resorcinol, exhibit good weather resistance. These materials are particularly attractive because they do not require coating to protect them from harmful weather influences, especially UV light. The ester structures of resorcinol and iso- and / or terephthalic acid can undergo so-called photo-Fries rearrangements upon contact with UV light. This results in, among other things, hydroxybenzophenone structures that are incorporated into the polymer chain. Hydroxybenzophenones are known to exhibit UV absorption properties. This explains their good weather resistance. This fact is described, for example, in US20030050400 Al. The alternative use of UV absorbers, on the other hand, is far less effective, since 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 requires protection especially against UV light, is relatively low. If a specialist wishes to use higher concentrations of UV absorbers, they are confronted with further disadvantages. Low-molecular-weight compounds, especially at higher concentrations, reduce mechanical properties. This is undesirable. To anchor higher concentrations of UV absorbers in the surface, it is common practice to protect UV-sensitive materials such as polycarbonate with coatings containing high concentrations of UV absorbers. However, coating 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-resistant and complex coating can be dispensed with.

[0005] The polyester carbonates described are produced in the prior art using an interfacial process. In this process, aromatic diols and OH-terminated ester blocks are condensed using phosgene. The OH-terminated ester blocks can also be produced 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 WO00026275 A1. In this document, polyester carbonates made from bisphenol A containing ester blocks made from resorcinol and terephthalic / isophthalic acid are described as preferred polymers. The ester blocks are produced in a dichloromethane / water mixture using aqueous NaOH solution starting from the acid chlorides of the 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.

[0006] According to DE60212172T2, the described polyestercarbonates are obtained by solid-state polymerization. The described process is relatively complex, as a step must always be carried out in which the polycarbonate used is at least partially crystallized. Furthermore, the document shows that, in particular, the use of activated carbonate sources (such as methyl salicylate-capped polycarbonate) achieves sufficient molecular weights of the polyestercarbonate, and randomization of the groups can be at least partially suppressed. This document uses exclusively OH-terminated oligoester blocks (i.e., the terminal groups of the oligoester are usually resorcinol). This results in the same bonds between the oligoester and the polycarbonate as described above for the interfacial process (see also Figure 2).The document explicitly states that the melt process is unsuitable for producing such polyester carbonates because it results in random copolymers (i.e., the polyester blocks degrade and are randomly distributed throughout the polymer). This alone demonstrates that the reaction conditions of a solid-state polymerization are not transferable to those of a melt process.

[0007] Processes based on the melt transesterification process known for polycarbonate are well known and have the advantage of eliminating the need for difficult-to-handle feedstocks such as phosgene. Another major advantage is that no solvents are required. Therefore, it would be industrially advantageous to produce polyester carbonates using the melt transesterification process. However, this process also presents challenges. For example, the highly reactive acid chlorides are difficult to replace with other feedstocks. Transesterification processes often involve long residence times in corresponding reactors. The high temperatures frequently result in the formation of by-products that negatively impact product quality. Since melt transesterification processes typically do not require complex downstream processing steps, impurities and catalyst residues remain in the product.These can impair product quality.

[0008] Furthermore, polycarbonates produced by the melt transesterification process have significantly higher contents of hydroxy-terminated end groups (content of phenolic OH groups) compared to corresponding products from the interfacial process. These phenolic OH groups can be damaged by oxidative processes, which impairs product quality. The optical properties in particular suffer as a result. However, it is important to maintain good optical properties, especially for a product that is intended to be characterized by high intrinsic weathering stability. It is therefore advantageous if the content of phenolic OH end groups in the resulting polymer is low. However, no teaching on this can be found in the prior art with regard to the aforementioned polyester carbonates, since the prior art relates exclusively to the production of polyester carbonates by interfacial reaction.

[0009] Since, for the reasons mentioned above, the reactivity of the reactants is lower compared to the starting materials in the interfacial process, it is also unknown how the above-mentioned polyester carbonates with high viscosity or molecular weight can be produced.

[0010] 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 as yet unpublished application EP21179513.3. The aromatic diacids and the aromatic diols are reacted using DPC. This process makes it possible to produce oligoesters with various end groups, e.g., OH end groups or phenyl ester or phenyl carbonate end groups.

[0011] Surprisingly, however, it was found that when such oligoesters react with aromatic polycarbonate prepolymers, the content of ester structures from the corresponding isophthalic acid and / or terephthalic acid and the corresponding aromatic diol, particularly resorcinol, in the polyester carbonate is present, but not sufficient to provide good intrinsic weathering stability. When the concentration of such structural elements is low, significantly fewer Fries products—particularly hydroxybenzophenone structures—result. Therefore, however, the intrinsic stabilization against UV light is significantly lower. This finding was surprising, since there is no prior art evidence that the above-mentioned structural elements are lost during transesterification.

[0012] W02005021616 A1 describes the melt-processing of hydroxy-terminated oligoester blocks. This study investigated how to achieve an OH end group content of the oligoesters comparable to that achieved in a solvent-based process. Different catalysts and the influence of the operating mode (e.g., different temperatures and vacuum) were also tested for this purpose. Furthermore, the oligoesters were subsequently condensed to form a polyester carbonate using an interfacial process. Therefore, this document cannot teach how the ester structures formed from isophthalic acid and / or terephthalic acid and resorcinol are retained during the melt transesterification process.WO2006057810 A1 describes oligoesters obtained by the melt transesterification process, which are characterized by a high proportion of carboxyl end groups. These carboxyl end groups are then used to incorporate the oligoesters into coating systems. Accordingly, the use of oligoesters in a melt transesterification process is not described here.

[0013] US20030050400 Al describes the preparation of oligomers from aromatic diacids and resorcinol. The underlying objective of US20030050400 Al is to provide OH-terminated building blocks that can then be converted into polyester carbonates using interfacial processes. Similar to W02005021616 Al, only the interfacial process is reported here, and therefore, conclusions regarding the obtainment of the desired ester structures in a melt process are not possible.

[0014] 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 of aromatic acid and aromatic diol (not bisphenol). Thus, one aspect of this invention was that the resulting polyester carbonate blends exhibit good intrinsic weathering resistance. This should result in particular from intact ester groups of isophthalic acid and / or terephthalic acid and the aromatic diol, in particular resorcinol or a derived compound.These intact groups are capable of forming hydroxybenzophenone structures and thus imparting UV absorption properties to the polyester carbonate blend. This can increase intrinsic weathering stability. Polyester carbonate blends should preferably also exhibit good processability. Most preferably, the blends should simultaneously have the lowest possible phenolic OH end group content. Thus, the polyester carbonate blends should preferably be weather-stable and / or essentially resistant to yellowing and / or essentially not prone to polymer degradation, for example, due to oxidative degradation. It is also preferred that no raw materials that pose handling challenges, such as phosgene, be 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, i.e., for example, comprising as few and / or inexpensive and / or energy-intensive steps as possible. At least one, preferably all, of the above-mentioned objects have been achieved by the present invention. Surprisingly, it has been 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 oligo- and / or polycarbonate according to the process of the invention or is thermally processed together with polycarbonate, a high proportion of ester structures composed of 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 low amount of oligocarbonate and / or polycarbonate in the first process step, and the resulting polyester carbonate prepolymer is reacted with a large amount of polycarbonate in a second process step, a polyester carbonate blend with a high proportion of ester structures composed of 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 in which a high proportion of the isophthalic acid and / or terephthalic acid groups are directly bonded to the aromatic diol, such as resorcinol. In addition, ester linkages composed of aromatic bisphenol, such as bisphenol A, and aromatic diacid are also present.

[0015] Without wishing to be bound by theory, the first process step, in which the oligoester is reacted in a large excess with the oligo- and / or polycarbonate, appears to lead to a polyestercarbonate prepolymer in which the few carbonate units bonded to the oligoester result in good compatibility with the polycarbonate used in the second process step. This enables both the polyestercarbonate prepolymer and the polycarbonate to be reacted into a homogeneous mixture in the second process step. This homogeneous mixture exhibits both good optical and mechanical properties. Furthermore, under these conditions, a large portion of the isophthalic acid and / or terephthalic acid ester to form the aromatic diol, which is different from bisphenol A, remains, so that the resulting blend is also intrinsically weather-stable.

[0016] Furthermore, the polyester carbonate blend can be produced using a solvent-free process. In particular, the use of difficult-to-handle substances such as phosgene can be dispensed with. Likewise, the process according to the invention comprises only a few steps (in particular, no complex crystallization step, for example, of the polycarbonate). Furthermore, these steps do not require the presence of a solvent (such as crystallization). Thus, the polyester carbonate blend is accessible using a simple and ecologically and / or economically advantageous process. In particular, the process according to the invention is also scale-up-capable. This preferably means that the process according to the invention can also be carried out on an industrial scale. This demonstrates, in particular, that the process according to the invention is controllable, and thus the scale can also be predictably scaled up.

[0017] In addition, the process according to the invention can produce a prepolymer and / or a blend 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 generally more expensive than classic "unactivated" groups (such as an oligocarbonate or a polycarbonate with phenoxy end groups) and, above all, must be prepared separately in an additional step.

[0018] According to the invention, therefore, in one aspect, there is provided a process for producing a polyester carbonate prepolymer, comprising the steps

[0019] (a) providing an oligoester comprising structures of formula (I), in which Ri independently represents a hydrogen atom, a halogen or an alkyl group having 1 to 4 carbon atoms and n is at least 4,

[0020] (b) providing an oligocarbonate and / or a polycarbonate and

[0021] (c) reacting from 65 to 95% by weight of the oligoester from step (a) with from 35 to 5% by weight of the oligocarbonate and / or polycarbonate from step (b), wherein the weight % refers to the sum of the weight of oligoester from step (a) and oligocarbonate and / or polycarbonate from step (b), by means of a melt condensation reaction to obtain a polyestercarbonate prepolymer.

[0022] The preparation 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 the preparation of OH-terminated oligoesters in particular (see, for example, Example 1 of WO2005 / 021616A1). A process for preparing an oligoester is also described in the as yet unpublished application EP21179513.3. It is preferred that the oligoester of step (a) be prepared in the absence of a solvent. This eliminates the need for further purification steps to convert the oligoester in step (c) according to the invention.

[0023] More preferably, the oligoester of step (a) is prepared by a process in which

[0024] [I] at least isophthalic acid and / or terephthalic acid are mixed with a diol of formula (3) and at least one diaryl carbonate of formula (4), wherein in which Ri represents a hydrogen atom, a halogen or an alkyl group having 1 to 4 carbon atoms, preferably hydrogen, and in which R2 each independently represents hydrogen or -COOCH3, preferably hydrogen,

[0025] [II] this mixture from step [I] is heated in the presence of at least one catalyst and

[0026] [III] vacuum is applied to the mixture from step [II] to obtain the oligoester.

[0027] The workup of the oligoester—if necessary and / or desired—can be carried out by methods known to those skilled in the art, for example, by precipitation. However, it is preferred that no solvents be used during the workup.

[0028] It is obvious to the person skilled in the art that R 1for example, in formula (I), formula (3), formula (300), formula (1a) and / or formula (7), the position is chosen so that the photo-Fries rearrangements are possible. For example, not all ortho positions may be represented by R 1 be blocked. However, the possible substitution pattern is obvious to the expert based on his or her expertise.

[0029] According to the invention, reference is occasionally made to an “aromatic diol.” This term is used in particular to distinguish it from a “bisphenol” (it is often also pointed out that an aromatic diol does not mean a bisphenol). The skilled person knows that a bisphenol is also an aromatic diol in the broadest sense. However, in the context of the present invention, he or she can make a corresponding distinction based on his or her specialist knowledge (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 formula (3). An aromatic diol is particularly preferably understood to mean resorcinol or a compound derived from resorcinol.A "bisphenol" within the meaning of the present invention is preferably a compound represented by formula (III) (see also "Y" in formula (II), where in formula (III) an OH group is present at each of the (the structure of formula (III) is thus a bisphenol structure formed by reaction of the OH groups; this relationship is known to the person skilled in the art). A particularly preferred bisphenol is bisphenol A.

[0030] The described process can also optionally comprise a further step in which the oligoester is reacted with a diphenyl diacid ester, preferably diphenyl isophthalate and / or diphenyl terephthalate. Such a reaction can reduce the OH end group content, if desired.

[0031] The oligoester of process step (a) can be OH-terminated, phenyl ester-terminated, acid-terminated, or phenyl carbonate-terminated, or contain mixtures of the aforementioned end groups. Preferably, the oligoester is OH-terminated, phenyl ester-terminated, phenyl carbonate-terminated, or any mixture of the aforementioned terminations is present. The skilled person can adapt the process according to the invention to the end group(s) present. For example, the termination can be influenced by the composition / ratio of the monomers used, the reaction temperature, the catalyst used, the application of the vacuum, and the strength of the vacuum. This can also influence the viscosity and the resulting glass transition temperature of the oligoester.

[0032] It is particularly preferred that the oligoester of process step (a) according to the invention at least partially has no OH terminations. Thus, the resulting polyester carbonate prepolymer or the resulting polyester carbonate blend preferably has essentially no, particularly preferably no, linkages of, for example, resorcinol to, for example, BPA via a carbonate bridge. Particularly preferably, the polyester carbonate prepolymer and / or the polyester carbonate blend according to the invention (both described further below) has essentially no, particularly preferably no, structures of formula (300), where in the structure of formula (300) Ri independently of one another represents a hydrogen atom, a halogen or an alkyl group having 1 to 4 carbon atoms, preferably represents the meanings given for Ri of formula (Ia), Y independently of one another represents a structure of formulas (III), (IV), (V) or (VI), preferably represents the meanings given for formula (II) and the "*" each indicate the positions with which the structure of formula (300) binds / would bind into the polymer chain of the polyester carbonate.

[0033] The phrase "essentially no structures of formula (III)" is understandable to those skilled in the art. It is clear that traces of such groups may be present due to impurities. However, according to the invention, they are preferably avoided.

[0034] In particular, it is preferred that the oligoester of process step (a) according to the invention at least partially has no OH terminations and that the polyester carbonate prepolymer according to the invention is particularly preferably obtained by this process.

[0035] 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 formula (3). The molar ratio of isophthalic acid and / or terephthalic acid to the diol of formula (3) is preferably 0.50 to 1.20, particularly preferably 0.70 to 1.15, and most preferably 0.75 to 1.12.

[0036] According to the invention, the diol of 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.

[0037] Preferably, both isophthalic acid and terephthalic acid are used in process step (I). If both diacids are used, 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 most 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 formula (4) is diphenyl carbonate.

[0038] Particularly preferably, a molar ratio of isophthalic acid and / or terephthalic acid to the diaryl carbonate of formula (4) of 1 to 2 - 2.5, more preferably of 1.0 to 2.01 - 2.25 and most preferably of 1.0 to 2.05 is used.

[0039] In process step (II), the mixture from process step (I) is heated in the presence of at least one catalyst. Preferably, in this process step (II), the individual components from process step (I) are melted. However, terephthalic acid in particular is insoluble under the given conditions, at least initially. However, this can change during process step (II). In process step (II), carbon dioxide is generally released. This procedure allows a rapid reaction under low temperature stress. Process step (II) is preferably carried out under a protective gas atmosphere, preferably under nitrogen and / or argon. Preferably, step (II) is carried out in the absence of a solvent. The term "solvent" in this context is familiar to the person skilled in the art.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 is preferably encompassed by the invention. However, according to the invention, an active step of adding such a solvent is preferably avoided.

[0040] 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 230°C to 300°C. Under these temperature conditions, the corresponding aryl alcohol of the diaryl carbonate, preferably phenol, may already be distilled off. Process step (II) is preferably carried out under atmospheric pressure. Stirring is preferably carried out under atmospheric pressure until gas evolution essentially stops. Alternatively, the temperature can also be increased stepwise - depending on the observed reactivity - to 200°C - 320°C, preferably 210 - 310°C, particularly preferably 215 - 300°C. The reactivity can be estimated from the 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 (e.g., discoloration) can occur at higher temperatures. Therefore, higher temperatures are less preferred.

[0041] Particularly preferably, the at least one catalyst is an organic base or a Lewis acid transition metal compound. The organic base is preferably an alkylamine, imidazole (derivatives), guanidine base such as triazabicyclodecene, DMAP and corresponding derivatives, 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) and diazabicycloundecene (DBU), most preferably DMAP. These catalysts offer 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 contains only a low catalyst content or no catalyst at all. This offers the particular advantage that no inorganic salts, which are always obtained, for example, via a route using phosgene, are present in the mixture of oligoesters and thus also not in the subsequent polyester carbonate.It is known that such salts can negatively affect the stability of the polyester carbonate, as the ions can have a catalytic effect upon corresponding degradation. Preferably, 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 used together with a phosphonium catalyst of formula (VIII) (see below). A mixture of 4-(dimethylamino)pyridine (DMAP) and tetrabutylphosphonium acetate is most preferably used as the catalyst in process step (II).

[0042] If the catalyst is a Lewis acid transition metal compound, it is preferred to use alkoxides of metals from Group IVB or tin, or derivatives of metals, metal oxides, or metal carboxylates from Group IVA of the Periodic Table. The Lewis acid 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 diesters, tin phenoxide, monobutyltin oxide, and any mixture of the above. Titanium butoxide is particularly preferred.

[0043] The at least one catalyst is preferably used 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 of formula (4). If more than one catalyst is used in the reaction, these catalysts are preferably used in total amounts of 1 to 5000 ppm, preferably 5 to 1000 ppm, and particularly preferably 300 to 700 ppm.

[0044] In process step (III), a vacuum is applied to the mixture obtained from process step (II). This distills off the corresponding aryl alcohol of the diaryl carbonate used, preferably phenol, and shifts the reaction equilibrium toward oligoesters. The aryl alcohol is the chemical compound released during the condensation reaction.

[0045] The term "condensation" or "condensation reaction" is familiar to those skilled in the art. This preferably refers to a reaction in which two molecules (of the same substance or different substances) combine to form a larger molecule, with a molecule of a chemically simple substance being split off. This compound split off during the condensation is removed by means of a vacuum in process step (III). Accordingly, it is preferred that the process according to the invention is characterized in that, during process step (III), the volatile constituents which have a boiling point below the mixture of oligoesters formed in process step (II) are separated off, optionally by gradually reducing the pressure. A stepwise separation is preferably chosen when different volatile constituents are being separated off.Likewise, a stepwise separation is preferred to ensure the most complete removal of the volatile component(s). The volatile components are the chemical compound(s) released during the condensation, preferably phenol.

[0046] The separation of the condensation product in process step (III) preferably takes place at temperatures of 200°C to 280°C, more preferably 210°C to 270°C, and especially preferably 220°C to 265°C. Furthermore, the vacuum during the separation is preferably 500 mbar to 0.01 mbar. In particular, it is preferred that the separation be carried out stepwise by reducing the vacuum. Most preferably, the vacuum in the final stage is 10 mbar to 0.01 mbar.

[0047] The oligoester thus obtained can optionally be used after further purification in process step (a). 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. This M nand / or all other molecular weights of the invention, unless otherwise stated, were determined by gel permeation chromatography in dichloromethane using a bisphenol A polycarbonate as the standard. The molecular weights Mw (weight average) and Mn (number average) of the oligoesters, oligocarbonates, polycarbonates, or polyestercarbonates used according to the invention were determined, unless otherwise stated, by size exclusion chromatography (gel permeation chromatography GPC; based on DIN 55672-1:2007-08 using a BPA polycarbonate calibration). Calibration was performed using linear polycarbonates of known molecular weight distribution (e.g., from PSS Polymer Standards Service GmbH, Germany). Method 2301-0257502-09D (from 2009 in German) from Currenta GmbH & Co. OHG, Leverkusen, was used. Dichloromethane was used as the eluent. The column combination consisted of cross-linked styrene-divinylbenzene resins.The GPC may comprise one or more commercially available GPC columns for size exclusion chromatography connected in series, which are selected so as to ensure sufficient separation of the molecular weights of polymers, in particular of aromatic polycarbonates with weight-average molecular weights M. w from 2,000 to 100,000 g / mol is possible. The analytical columns typically have a diameter of 7.5 mm and a length of 300 mm. The particle sizes of the column material range from 3 pm to 20 pm.

[0048] 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 most preferably 2000 g / mol to 8000 g / mol. In this specific case, the M nPreferably measured by GPC with polystyrene calibration in THF. Calibration is preferably performed with polystyrenes in a molecular weight range of 500 to 7,000,000 g / mol. GPC is preferably performed in tetrahydrofuran (preferably THF stabilized with 0.007–0.015 wt.% butylhydroxytoluene) modified with 0.8% acetic acid. The flow rate is preferably 1 mL / min at 40 °C. Furthermore, the preferred column combination is Waters Acquity® APC™ Column Manager - S with three Acquity® APC™ columns (450Å, 125Å and 45Å pore diameter) with I / d = 150 / 4.6 mm and which is filled with particles with a particle diameter of 2.5 (the 450Å and the 125Å column) or 1.7 µm (the 45Å column) (1 pm = IxlO -6m) are used. Detection is carried out here by means of a refractive index detector. The oligoester of step (a) preferably has at least one type of end group selected from the group consisting of -OH end groups (e.g., of 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 desired mixtures. Likewise, they can be present in any desired amounts or ratios to one another.

[0049] Further chemical properties of the oligoester are described, for example, in WO 2005 / 021616 A1. 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.

[0050] 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 thus a higher molecular weight than an oligocarbonate. According to the invention, the term "oligo"mer is preferably used when the substance in question does not have sufficient mechanical strength on its own. A corresponding "polymer"mer, on the other hand, does. A sharp distinction between the two terms does not appear to be crucial according to the invention. 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 likewise preferred that the polycarbonate of step (b), but also of step (iii) of the process according to the invention for producing a polyester carbonate 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 of 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 very particularly 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 / l at 25 °C using an Ubbelohde viscometer.The determination of relative solution viscosity using an Ubbelohde viscometer is familiar to those skilled in the art. According to the invention, this is preferably carried out according to DIN 51562-3; 1985-05. The flow times of the polyester carbonate to be measured through the Ubbelohde viscometer are measured to subsequently determine the viscosity difference between the polymer solution and its solvent. For this purpose, the Ubbelohde viscometer is first calibrated by measuring the pure solvents dichloromethane, trichloroethylene, and tetrachloroethylene (at least three measurements are always taken, and no more than nine). This is followed by the actual calibration with the solvent dichloromethane. The polymer sample is then weighed, dissolved in dichloromethane, and the flow time for this solution is determined three times. The mean of the flow times is corrected using the Hagenbach correction, and the relative solution viscosity is calculated.

[0051] 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 further below with reference to the polyester carbonate blend.

[0052] It is preferred that the oligocarbonate and / or polycarbonate used in process step (b) does not have any end groups of the formula (301) where in formula (301), the "*" represents the bonding of the structure of formula (301) to the oligocarbonate and / or polycarbonate. Thus, an activated carbonate source is preferably not used. This is also preferably not necessary according to the invention, since the reaction in process step (c) proceeds smoothly under the defined conditions.

[0053] 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. 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). Preferably, 70 to 93% by weight, particularly preferably 75 to 90% by weight of the oligoester from step (a) is reacted with 30 to 7% by weight, particularly preferably 25 to 10% by weight of the oligocarbonate and / or polycarbonate from step (b), the weight % being based on the sum of the weight of oligoester from step (a) and oligocarbonate and / or polycarbonate from step (b).

[0054] In process step (c) according to the invention, a condensation reaction takes place. The term "condensation reaction" has already been defined above. Those skilled in the art know how to influence such equilibrium reactions to produce the desired product. In particular, it is preferred according to the invention that step (c) is carried out at a pressure reduced relative to ambient pressure. This allows the compound formed during the condensation to be removed by means of a vacuum. Accordingly, it is preferred that the process according to the invention is characterized in that, during process step (c), the volatile constituents which have a boiling point below that of the polyester carbonate prepolymer formed in process step (c) are separated off, optionally with a stepwise reduction in pressure. A stepwise separation is preferably chosen when different volatile constituents are separated off.Likewise, a stepwise separation is preferably selected to ensure the most complete separation possible of the volatile component(s). The volatile components are preferably the chemical compound(s) eliminated during the condensation, preferably phenol. However, the volatile components can also be the unreacted diol of formula (3) and / or the unreacted diaryl carbonate of 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 knows that appropriate temperatures may be necessary in process step (c) to obtain appropriate yields of polyester carbonate prepolymer.

[0055] It is preferred that the oligoester used according to process step (a) and / or the oligocarbonate and / or polycarbonate used according to process step (b) are amorphous.

[0056] The process according to the invention thus provides a polyester carbonate prepolymer through the reaction of the oligoester with the oligocarbonate and / or polycarbonate. Therefore, in a further aspect of the present invention, a polyester carbonate prepolymer is provided which is obtained by the process according to the invention for producing a polyester carbonate prepolymer in preferably all of the above-described embodiments, in particular also in combination with preferred embodiments. Likewise, a polyester carbonate prepolymer is provided, comprising

[0057] (A) Ester groups of the formula (la) in which Ri independently represents a hydrogen atom, a halogen or an alkyl group having 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,

[0058] (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

[0059] R6 and R7 each independently represent hydrogen, Ci-Cis-alkyl, Ci-Cis-alkoxy, halogen or optionally substituted aryl or aralkyl, and

[0060] X represents a single bond, -CO-, -O-, -S-, Ci- to C ( , -alkylene. C2 to Cs alkylidene, Ce bis

[0061] Cio-cycloalkylidene or C - to Ci2-arylene, which may optionally be condensed with further aromatic rings containing heteroatoms,

[0062] (IV) (V) (VI), where in these formulas (IV) to (VI) R 3 each represents Ci-C4-alkyl, aralkyl or aryl, preferably methyl or phenyl, most preferably methyl, and the "*" each indicate the positions with which the formulas (III), (IV), (V) or (VI) are bonded 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 bonded into the polyester carbonate blend, wherein at least some of the ester groups (A) are directly linked to at least some of the carbonate groups (B) via the formula (VII), wherein

[0063] (VII), in which Y has the meanings described above for (B) and (A) represents the linkage to the ester group (A) and (B) represents the linkage to the carbonate group (B), and which is further characterized in that the polyester carbonate prepolymer contains more mol% of carbon atoms, as indicated by an arrow in formula (Ia), than mol% of carbon atoms, as indicated by an arrow in formula (VII), This polyester carbonate prepolymer is preferably obtained by the process according to the invention for producing a polyester carbonate prepolymer in preferably all embodiments described above, in particular also in combination of preferred embodiments.

[0064] The determination of structural formulas (Ia) and (VII) is described in particular below for the polyester carbonate blend of the invention. The skilled person will be able to apply all statements regarding the blend to the polyester carbonate prepolymer where applicable and appropriate.

[0065] The polyester carbonate prepolymer according to the invention has a higher molecular weight than the starting oligoester from step (a), but its molecular weight depends strongly on the oligocarbonate and / or polycarbonate used. The polyester carbonate prepolymer also exhibits structures of formula (7) as a result of the reaction:

[0066] (7), in which Ri has the meanings given for formula (I), Y has the meanings given below (Y is derived from the bisphenols used to prepare 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.

[0067] In particular, the polyester carbonate prepolymer according to the invention, as also described, for example, in the process according to the invention, is prepared 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) are reacted with 35 to 5% by weight of the oligocarbonate and / or polycarbonate (for example from step (b), as described above). Preferably, 70 to 93% by weight, particularly preferably 75 to 90% by weight of the oligoester (for example from step (a), as described above) are reacted 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-% based on the sum of the weight of oligoester and 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.

[0068] Furthermore, the polyester carbonate prepolymer according to the invention preferably does not contain methyl 2-hydroxybenzoate. Traces of such a compound can be detected in the prepolymer, for example, by NMR spectroscopy. They can remain in the polyester carbonate prepolymer if activated carbonate sources (e.g., oligocarbonates and / or polycarbonates with end groups of formula (301)) are used to prepare the polyester carbonate prepolymer. Accordingly, the polyester carbonate prepolymer according to the invention also preferably does not contain an end group of formula (301).

[0069] According to the invention, it was found that a reaction had taken place between the oligoester and the oligocarbonate and / or polycarbonate. This was evident from the fact that the resulting polyestercarbonate prepolymer was essentially transparent. The term "transparent" is preferably understood here as stated for the polyestercarbonate blend.

[0070] It has been found according to the invention that the resulting polyester carbonate prepolymer is suitable for providing, by mixing and / or reacting with another polycarbonate, a polyester carbonate blend that meets the high mechanical and optical requirements of a standard polycarbonate while simultaneously exhibiting intrinsic weather resistance. Without wishing to be bound by theory, the polyester carbonate prepolymer appears to act as a compatibilizer, enabling a homogeneous mixture between the ester groups and the polycarbonate to be achieved. In particular, the polyester carbonate prepolymer according to the invention is suitable for use in the process according to the invention for producing a polyester carbonate blend.

[0071] In a further aspect of the present invention, a process for producing a polyester carbonate blend is provided, comprising the steps

[0072] (i) Providing the polyester carbonate prepolymer according to the invention, preferably in all the above-described embodiments and also combinations of preferences,

[0073] (ii) providing a polycarbonate having 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,

[0074] (iii) converting the polyestercarbonate prepolymer from step (i) and the polycarbonate from step (ii) into a molten state and mixing, in the molten state, from 5 to 25 wt.% of the polyestercarbonate prepolymer with 95 to 75 wt.% of the polycarbonate, wherein the wt.% refers to the sum of the weights of polyestercarbonate prepolymer from step (i) and polycarbonate from step (ii), to obtain a polyestercarbonate blend. It will be apparent to those skilled in the art that process step (i) preferably comprises the process steps (a) to (c) described above.

[0075] 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 polyester-carbonate blend of the invention differs from that for producing the polyester-carbonate prepolymer of the invention in that, firstly, a polycarbonate (and not an oligocarbonate) is mandatory for producing the polyester-carbonate blend of the invention, and secondly, this polycarbonate is used in excess of the polyester-carbonate prepolymer. The use of a polycarbonate (as opposed to an oligocarbonate) in process step (ii) is essential because it is the only way to ensure good mechanical properties of the polyester-polycarbonate blend, preferably comparable to a standard polycarbonate. This polycarbonate is preferably an aromatic polycarbonate.Most preferably, the polycarbonate is a polycarbonate having repeating units of formula (II). in which Y independently represents a structure of the formulas (III), (IV), (V) or (VI), where in the

[0076] R6 and R7 each independently represent hydrogen, Ci-Cis-alkyl, Ci-Cis-alkoxy, halogen or optionally substituted aryl or aralkyl, and

[0077] X represents a single bond, -CO-, -O-, -S-, Ci- to C ( , -alkylene. C2- to C5-alkylidene, C1- to C10-cycloalkylidene or C1- to C12-arylene, which may optionally be condensed with further aromatic rings containing heteroatoms,

[0078] (IV) (V) (VI), where in these formulas (IV) to (VI) R 3each represents C1-C4-alkyl, aralkyl, or aryl, preferably methyl or phenyl, most preferably methyl, and the "*" indicates the positions at which 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 calculated from the defined molecular weight of the polycarbonate used). Most preferably, the polycarbonate of process step (b) is based on bisphenol A.

[0079] In process step (iii), the polyester carbonate 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 selected at which both components are in a molten state. In particular, a temperature should be selected that is above the glass transition temperature and / or the melting point, preferably above the glass transition temperature, of the polyester carbonate 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.

[0080] In process step (iii), the polyester carbonate prepolymer is used in a substoichiometric amount relative to the polycarbonate. Preferably, 8 to 35 wt.%, particularly preferably 10 to 30 wt.%, very particularly preferably 15 to 25 wt.% of the polyester carbonate prepolymer is mixed with 92 to 65 wt.%, particularly preferably 90 to 70 wt.%, very particularly preferably 85 to 75 wt.% of the polycarbonate in the molten state, where the wt.% is based on the sum of the weight of polyester carbonate prepolymer from step (i) and polycarbonate from step (ii).

[0081] In process step (iii), in one embodiment, a reaction can take place between the polyester carbonate prepolymer and the polycarbonate. This is, in particular, a condensation reaction, as described in more detail above. In another embodiment, no reaction takes place between the two components. A physical mixture is thus obtained. However, the polyester carbonate blend according to the invention is in any case a single-phase, homogeneous mixture. In particular, the term “homogeneous mixture” is to be understood according to the invention as meaning that, with regard to phase morphology, there are no two discrete, distinguishable phases, but only one homogeneous phase. This can be demonstrated in particular by the transparency of the polyester carbonate blend according to the invention.For the purposes of the present invention, "transparent" preferably refers to blends that exhibit a light transmission in the VIS range of the spectrum (380 to 780 nm) of more than 20% (TVIS transmittance), determined according to DIN ISO 13468-2:2006 (D65, 10°, sample plate layer thickness: 4 mm). They also preferably exhibit a haze of less than 10%, determined according to ASTM D1003:2013. In particular, this refers to blends that exhibit visual transparency, i.e., they reproduce the background and can thus be used, for example, as a transparent cover.

[0082] Thus, according to the invention, the term “blend” encompasses both physical mixtures and mixtures in which at least part of the polyester carbonate prepolymer has reacted with the polycarbonate.

[0083] Methods are known to those skilled in the art by which they can influence whether or not a reaction takes place in process step (iii). Since the reaction is preferably a condensation reaction, the above statements apply analogously here. In particular, it is preferred if process step (iii) is carried out at a pressure reduced in relation to the ambient pressure. This allows the compound formed during the condensation to be removed by means of a vacuum. Accordingly, it is preferred that the process according to the invention is characterized in that, during process step (iii), the volatile constituents which have a boiling point below that of the polyester carbonate blend formed in process step (ii) are separated off, if appropriate with a stepwise reduction in pressure. A stepwise separation is preferably chosen if different volatile constituents are separated off.A stepwise separation is also preferred to ensure the most complete removal of the volatile component(s). The volatile components are the chemical compound(s) released during the condensation.

[0084] Likewise, a catalyst familiar to one 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 influence the stability of the polyester carbonate blend. The process according to the invention can also be carried out in the presence of a catalyst, particularly preferably in the presence of a basic catalyst.

[0085] All inorganic or organic basic compounds can be used as catalysts, for example lithium, sodium, potassium, cesium, calcium, barium, magnesium, hydroxides, carbonates, halides, phenolates, diphenolates, fluorides, acetates, phosphates, hydrogen phosphates, boranates, nitrogen and phosphorus bases such as

[0086] Tetramethylammoniumhydroxid, Tetramethyl-ammoniumacetat, Tetramethylammonium-fluorid, Tetramethylammoniumtetraphenylboranat, Tetraphenylphosphoniumfluorid, Tetra- phenylphosphoniumtetraphenyl-boranat, Dimethyl-diphenylammoniumhydoxid, Tetraethyl- ammoniumhydroxid, Cethyltrimethylammonium-tetraphenylboranat, Cethyltrimethyl- ammoniumphenolat, l,8-Diazabicyclo[5.4.0]undec-7-en (DBU), 1,5-Diazabicyclo [4.3.0]non-5-en (DBN) oder Guanidinsysteme wie beispielsweise das l,5,7-Triazabicyclo-[4,4,0]-dec-5-en, 7- Phenyl-l,5,7-triazabicyclo-[4,4,0]-dec-5-en, 7-Methyl-l,5,7-triazabicyclo-[4,4,0]-dec-5-en, 7,7'- Hexylidendi-l,5,7-triazabi-cyclo-[4,4,0]-dec-5-en, 7,7'-Decylidendi-l,5,7-triazabicyclo-[4,4,0]-dec- 5-en, 7,7'-Dodecyliden-di-l,5,7-tri-aza-bicyclo-[4,4,0]-dec-5-en oder Phosphazene wie beispielsweise die Phosphazen-Base Pl-t-Oct = tert. -Octyl -imino-tris-(dimethylamino)-phosphoran, Phosphazen-Base Pl-t-Butyl = tert. -Butyl -imino-tris-(dimethylamino)-phosphoran, BEMP = 2-tert.- Butylimino-2-diethylamino-1,3-dimethyl-perhydro-1,3,2-diaza-2-phosphoran, in question.

[0087] Phosphonium catalysts of the formula (VIII) are particularly suitable: where Ra, Rb, Rc and Rd can be the same or different C1-C10 alkyls, C6-C14 aryls, C7-C15 arylalkyls or C5-C6 cycloalkyls, preferably methyl or C6-C14 aryls, particularly preferably methyl or phenyl, and X- can be an anion such as hydroxide, sulfate, hydrogen sulfate, hydrogen carbonate, carbonate or a halide, preferably chloride or an alkylate or arylate of the formula -OR, where R can be a C6-C14 aryl, C7-C15 arylalkyl or C5-C6 cycloalkyl, preferably phenyl.

[0088] 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 up to 10' 8 Mol, based on 1 mol of the polyester carbonate prepolymer. The amounts of alkaline salts used as cocatalyst can be in the range of 1 to 500 ppb, preferably 5 to 300 ppb, and particularly preferably 5 to 200 ppb.

[0089] 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. It is likewise 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. It is likewise preferred that no vacuum is applied in process step (iii). It is particularly preferred that process step (iii) is carried out at the abovementioned temperatures in combination with the abovementioned pressures. In particular, it is preferred that the components in process steps (i) and (ii) are initially present as solids. 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. Mixing in process step (iii) preferably takes place at this temperature.

[0090] 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 between the components is explicitly desired or whether mixing is intended. However, the invention does not rule out the possibility of a reaction between the components occurring even in the latter case. Mixing is preferably achieved by laminar mixing of the components in the molten state.

[0091] For process step (iii), preference is given to using reactors suitable for processing highly viscous masses, which provide a sufficient residence time with thorough mixing, and which subject the polyester carbonate prepolymers and the polycarbonates to the optionally desired vacuum. 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 process according to the invention are described, for example, in EP3318311A1, EP1792643A1, DE19535817A1, DE102012103749A1, DE2011493A1 or DD-226778B1 or in the 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", wherein the thin-film evaporator disclosed in DE19535817A1, DD-226778B1 or that disclosed in EP3318311A1 or that disclosed in [1], Fig. 7, page 58, and Fig. 9, page 60, is particularly suitable for carrying out the process according to the invention. Furthermore, reactors according to EP460466A1, EP528210A1, EP638354A1, EP715881A2, EP715882A2, EP798093A2 can also be used according to the invention, or those according to EP329092A1, EP517068A1, or EP1436073A1 as well as those according to EP222599A2 can be used.

[0092] The time for mixing the components in process step (iii) depends, as is known to those skilled in the art, on the reactor(s) used. In general, short mixing times are preferred.

[0093] Process step (iii) can be carried out without the presence of at least one stabilizer. However, it has proven 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.

[0094] Such a stabilizer is also frequently 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 can also suppress the actual reaction between the oligomers or polymers. The suitability of a particular compound for use as a stabilizer within the meaning of the present invention and the determination of the appropriate amount of such a stabilizer within the meaning of the invention can be determined by preparing a mixture of the polyester carbonate blend and the additive and determining the effect on the melt viscosity, relative solution viscosity, and / or the transesterification activity.Considering the embodiment in which a vacuum is applied in process step (iii), a compound is particularly more suitable as a stabilizer within the meaning of the present invention, the smaller 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 within the meaning of the present invention, the smaller the reduction in molecular weight (for example, measured via the relative solution viscosity). The transesterification activity of a compound can be determined by measuring a 13C-NMR spectrum and comparison of the different ester bands (see also the process description in the examples section). The more carbon atoms present, as indicated by an arrow in formula (1a), the more effective the compound under investigation is, particularly as a stabilizer within the meaning of the present invention. Brönsted acids are used in particular.Specific examples of useful Bronsted 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, nicotinic acid, fumaric acid, maleic acid, oxalic acid, benzenesulfic acid, toluenesulfic 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 wt.% 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, polyester, or polyester carbonate.

[0095] Epoxy compounds containing at least one epoxy group in the molecule can also be used as stabilizers. These can be used in amounts of 0.001 wt.% to 0.5 wt.%, preferably 0.005 to 0.2 wt.%, 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,

[0096] Cyclohexylmethyl-3 ,4-epoxycyclohexancarboxylat, 3 ,4-Epoxy-6-methylcyclohexyhnethyl-6- methylcyclohexancarboxylat, Bisphenol-A-diglycidylether, Tetrabrombisphenol-A-glycidylether, Diglycidylester von Phthalsäure, Diglycidylester von Hexahydrophthalsäure, Bis- epoxydicyclopentadienylether, Bis-epoxyethylenglycol, Bis-epoxycyclohexyl Adipat, Butadiendiepoxid, Tetraphenylethylenepoxid, Octylepoxyphthalat, epoxidiertes Polytutadien, 3,4- Dimethyl-l,2-epoxychlorhexan, 3-Methyl-5-t-butyl-l, 2-epoxycyclohexan, Octadecyl-2,2- dimethyl-3, 4-epoxycyclohexancarboxylat, n-Butyl-2,2-dimethyl-3, 4-epoxycyclohexancarboxylat, Cyclohexyl-2-methyl-3,4-epoxycyclohexancarboxylat, n-Butyl-2-isopropyl-3,4-epoxy-5- methylcyclohexancarboxylat, 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-1,2-cyclohexanedicarboxylate, and di-n-butyl-3-t-butyl-4,5-epoxy-cis-1,2-cyclohexanedicarboxylate; these epoxy compounds can be used either individually or in admixture. These epoxy compounds can also be used together with the above-mentioned acid compounds.

[0097] Furthermore, alkyl phosphates, such as mono-, di-, and trihexyl phosphate, triisooctyl phosphate, and trinonyl phosphate, can be used as stabilizers. Triisooctyl phosphate (tris-2-ethylhexyl phosphate) is preferably used as the alkyl phosphate. Mixtures of various mono-, di-, and trialkyl phosphates can also be used. These can be used in amounts of 0.001 to 0.1 wt.%, preferably 0.005 to 0.05 wt.%, based on the total weight of all components used.

[0098] Likewise, at least one further additive may also be present during process step (iii) and / or process step c) (which differs from the optionally present stabilizer described above). Such additives, as are typically added to polycarbonates, are, in particular, thermal or processing stabilizers, antioxidants, especially phenolic antioxidants, mold release agents, flame retardants, anti-drip agents, UV absorbers, IR absorbers, antistatic agents, optical brighteners, fillers, light scattering agents, hydrolysis stabilizers, and / or additives for laser marking, particularly in the amounts customary for polycarbonate-based compositions. Such additives are described, for example, in EP 0 839 623 A1, WO 96 / 15102 A1, EP 0 500 496 A1, or in the "Plastics Additives Handbook," Hans Zweifel, 5th Edition 2000, Hanser Verlag, Munich. These additives can be added individually or as a mixture.

[0099] Phosphites, phosphonites, and phosphines can be used as thermal or processing stabilizers. Examples include triphenyl phosphite, diphenyl alkyl phosphite, phenyl dialkyl phosphite, tris(nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl phosphite, distearyl pentaerythritol diphosphite, and tris(2,4-di-tert-butylphenyl) phosphite.

[0100] Diisodecylpentaerythritoldiphosphit, Bis(2,4-di-tert-butylphenyl)pentaerythritoldiphosphit, Bis(2,4- di- cumylphenyl)pentaerythritol diphosphit, Bis(2,6-di-tert-butyl-4- methylphenyl)pentaerythritoldiphosphit, Diisodecyloxypentaerythritoldiphosphit, Bis(2,4-di-tert- butyl-6-methylphenyl)- pentaerythritoldiphosphit, Bis(2,4,6-tris(tert- butylphenyl)pentaerythritoldiphosphit, Tristea-rylsorbitoltriphosphit, Tetrakis(2,4-di-tert- butylphenyl)-4,4'-biphenylen diphosphonit, 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)methylphosphit, Bis(2,4- di-tert-butyl-6-methylphenyl)ethylphosphit, 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)phosphit], 2-Ethylhexyl(3,3',5,5'-tetra-tert-butyl-l,r-biphenyl-2,2'-diyl)phosphit, 5-Butyl-5-ethyl-2-(2,4,6-tri-tert-butylphenoxy)-l,3,2-dioxaphosphiran, Bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, triphenylphosphine (TPP), trialkylphenylphosphine, bisdiphenylphosphinoethane, or trinaphthylphosphine. Particular preference is given to using triphenylphosphine (TPP), Irgafos® 168 (tris(2,4-di-tert-butylphenyl)phosphite), and tris(nonylphenyl)phosphite, or mixtures thereof.

[0101] Preferred phenolic antioxidants include alkylated monophenols, alkylated thioalkylphenols, hydroquinones, and alkylated hydroquinones. 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) are particularly preferred.

[0102] These thermal or processing stabilizers and / or phenolic antioxidants can be used in amounts of 0.5 to 0.001 wt.% based on the total weight of all components present. They can be used individually or as mixtures with the above-mentioned additives. They can be added directly or as a masterbatch.

[0103] The process according to the invention for producing a polyester carbonate blend thus provides a polyester carbonate blend that is either a physical mixture and / or a reaction product of the polyester carbonate prepolymer and the polycarbonate. Therefore, the invention also provides a polyester carbonate blend obtained by the process according to the invention for producing a polyester carbonate blend, preferably in the above-mentioned embodiments or any combination of preferred embodiments.

[0104] In a further aspect of the present invention, a polyester carbonate blend is provided comprising

[0105] (A) Ester groups of the formula (la) in which Ri independently represents a hydrogen atom, a halogen or an alkyl group having 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,

[0106] (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

[0107] R6 and R7 each independently represent hydrogen, Ci-Cis-alkyl, Ci-Cis-alkoxy, halogen or optionally substituted aryl or aralkyl, preferably hydrogen, and

[0108] X represents a single bond, -CO-, -O-, -S-, Ci- to C (, -alkylene. C2- to C5-alkylidene, C to C10-cycloalkylidene or C1- to C12-arylene, which may optionally be condensed with further aromatic rings containing heteroatoms, preferably a single bond, C2- to C5-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, most preferably methyl, and the "*" each indicate the positions with which the formulas (III), (IV), (V) or (VI) are bonded 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 bonded into the polyester carbonate blend, wherein at least some of the ester groups (A) are directly linked to at least some of the carbonate groups (B) via the formula (VII), wherein

[0109] (VII), in which Y has the meanings described above for (B) and (A) represents the linkage to the ester group (A) and (B) represents the linkage to the carbonate group (B), wherein the polyester carbonate 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 very particularly preferably 1.22 to 1.33, characterized in that the polyester carbonate blend contains more mol% of carbon atoms, as indicated by an arrow in formula (Ia), than mol% of carbon atoms, as indicated by an arrow in formula (VII),

[0110] (la), where Ri, n and “*” are the above-mentioned

[0111] have meanings and

[0112] (VII), where (A), Y and (B) have the meanings given above.

[0113] 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 (optionally also oligocarbonate, e.g. from unreacted residues of process step (c) or by reaction in process step (c)) via an ester (see formula (VII). The formula (VII) is explained in more detail above by formula (7).

[0114] The presence of a structure of formula (VII) can be determined by NMR. This is illustrated by a direct linkage of bisphenol units to isophthalic acid and / or terephthalic acid units. This linkage is an ester linkage. The presence of this linkage can be determined by 13 C-NMR spectroscopy by determining the chemical shift of the carbonyl carbon atom indicated by an arrow in formula (Vila).

[0115] (Villa).

[0116] 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 determine the position of the carbon marked with the arrow in formula (Vila) in the 13 C-NMR to find out / calibrate.

[0117] Polyestercarbonates produced by the interfacial process, which comprise the ester groups (A) and (B), do not exhibit 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 directly bonded to a BPA unit via a carbonate group. The same applies to the polyestercarbonate of DE60212172T2.

[0118] The carbon atom indicated by an arrow in formula (VII) above can be formed either by reacting 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 absorption capacity of the polymer. A certain block length of these esters must be present for the resulting product to have intrinsic weathering stability. Nevertheless, the polyestercarbonate blend according to the invention always contains certain detectable proportions of these carbon atoms. It will be apparent to those skilled in the art that formula (VII) above has been depicted once with and once without an arrow. For better understanding, formula (VII) with an arrow can also be referred to as formula (VIIx).Therefore, according to the invention, it is essential that more mol% of carbon atoms, as indicated by an arrow in formula (Ia), are present in the polyester carbonate blend than mol% of carbon atoms, as indicated by an arrow in formula (VII). It will be apparent to those skilled in the art that formula (Ia) was depicted above once with and once without an arrow. For clarity, formula (Ia) with an arrow can also be referred to as formula (Iax). 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 weathering stability.

[0119] The ratio of the mol-% of the carbon atoms indicated in formulas (Iax) and (VIIx) can preferably be determined via 13Determine by C-NMR spectroscopy. The polyester carbonate blend is preferably dissolved in CDCl. 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 formula (Iax) 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 approximately 164-165 ppm (see also experimental section). The carbon atom marked in formula (Iax) is usually found at a chemical shift of 163-164 ppm if the diol of formula (3) is resorcinol. To determine the ratio of the mol-% of 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.

[0120] It is obvious to the person 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 is also obvious that n and m as well as the number of ester groups (A) and / or carbonate groups (B) must be selected such that the corresponding solution viscosity of the polyester carbonate blend results. Conversely, the person skilled in the art is able to derive a number-average molecular weight from a solution viscosity. It is equally obvious to the person skilled in the art to infer n or m 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 order of magnitude of the average number of repeat 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 due to reactions in process step (iii).Preferably, m in formula (II) is 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) based on 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 (Ia) and (II).

[0121] As will be apparent to those skilled in the art, the term “blend” is preferably to be understood here 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 is particularly evident when the polyester carbonate blend according to the invention is produced by the process according to the invention for producing a polyester carbonate blend. The polyester carbonate blend according to the invention preferably additionally comprises a component (X), which is a polycarbonate. This is particularly preferably a polycarbonate having repeat units of the formula (II), as explained in more detail above. The skilled person is in particular able to transfer the statements regarding the process according to the invention for producing a polyester carbonate blend to the polyester carbonate blend according to the invention.

[0122] Furthermore, the polyester carbonate blend according to the invention preferably does not contain methyl 2-hydroxybenzoate. Traces of such a compound can be detected in the blend, for example, by NMR spectroscopy. They can remain in the polyester carbonate blend if activated carbonate sources (e.g., polycarbonates with end groups of formula (301)) are used to prepare the polyester carbonate blend. Accordingly, the polyester carbonate blend according to the invention also preferably does not contain an end group of formula (301).

[0123] It is preferred that the polyester carbonate blend according to the invention is characterized in that the polyester carbonate 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 good processability of the polyester carbonate blend, for example, by injection molding. Likewise, this relative solution viscosity enables it to exhibit good mechanical properties for interesting applications such as automotive exteriors. The polyester carbonate blend is highly stable and intrinsically weather-resistant.

[0124] 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 by infrared spectroscopy. It can also be determined by 1 H-NMR can be determined. However, an overlap of the signals can occur. Therefore, it is preferred to determine the content of phenolic OH groups by infrared spectroscopy. For this purpose, the polyester carbonate blend is preferably dissolved in dichloromethane (2 g / 50 ml) and analyzed by evaluating the band at a wavenumber of 3583 cm' 1The required calibration of the infrared device is known to the expert.

[0125] Both the polyester carbonate prepolymer according to the invention and the polyester carbonate blend according to the invention can contain rearrangement structures (for example, the Fries rearrangement structures known to those skilled in the art). This can result, on the one hand, from the fact that reactions are carried out in the melt in the processes according to the invention. As the skilled person knows, corresponding structures can form under melt transesterification conditions. In addition, however, the oligocarbonates and / or polycarbonates used according to the invention can also already have such Fries structures. It has been found according to the invention that these Fries rearrangement structures do not have a particularly adverse effect on the properties of the polyester carbonate prepolymer and / or blend according to the invention.

[0126] In particular, the polyester carbonate prepolymer according to the invention and / or the polyester carbonate 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 may independently of one another be mono- or disubstituted by C1-C8 alkyl, halogen, preferably C1 to C4 alkyl, particularly preferably by methyl, and X represents a single bond, C1 to C6 alkylene, C2 to C5 alkylidene or C5 to C6 cycloalkylidene, preferably a single bond or C1 to C4 alkylene and particularly preferably isopropylidene. The total amount of structural units (4y) to (7y) (determined after saponification) is 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.

[0127] To determine the amount of rearrangement structures, the respective polymer is subjected to total saponification, forming the corresponding degradation products of formulas (4ya) to (7ya), the amount of which is determined using HPUC. Structures (4ya) to (7ya) are given as examples for the use of a polycarbonate containing 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 formulas (4ya) to (7ya) are determined using HPUC with UV detection.) The amount of the compound of formula (4ya) released is preferably 20 to 800 ppm, particularly preferably 25 to 700 ppm and especially preferably 30 to 500 ppm.

[0128] The amount of compound of formula (5ya) released is preferably 0 (i.e., below the detection limit of 10 ppm) to 100 ppm, particularly preferably 0 to 80 ppm, and especially preferably 0 to 50 ppm. The amount of compound of formula (6ya) released is preferably 0 (i.e., below the detection limit of 10 ppm) to 800 ppm, further preferably 10 to 700 ppm, particularly preferably 20 to 600 ppm, and most preferably 30 to 350 ppm.

[0129] Preferably, the amount of the compound of formula (7ya) released is 0 (ie below the detection limit of 10 ppm) to 300 ppm, preferably 5 to 250 ppm and particularly preferably 10 to 200 ppm.

[0130] In a further aspect of the present invention, there is provided a use of the polyester carbonate prepolymer according to the invention, 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 having 1 to 4 carbon atoms and n is at least 4, with a polycarbonate.

[0131] As already described above, it has been found according to the invention that the polyester carbonate prepolymer improves the incorporation of the oligoester groups into a polycarbonate. This results in the single-phase system described above. In addition to the compatibilizing effect, the polyester carbonate prepolymer can also be bonded to the polycarbonate by chemical reaction. Preferred definitions of the chemical structures are given below. These preferences apply to the process according to the invention for producing a polyester carbonate prepolymer, the polyester carbonate prepolymer according to the invention, the process according to the invention for producing a polyester carbonate blend, the polyester carbonate blend and / or the use according to the invention of the polyester carbonate prepolymer, each independently of one another or simultaneously. The person skilled in the art will appreciate that some chemical formulas have relationships (e.g.Formula (I) and formula (Ia)) or they can be derived from each other.

[0132] According to the invention, it is preferred that Ri in formula (I) and / or (Ia) stands for hydrogen. It is likewise preferred that Y in formula (II) stands for a structure of the formula (III). It is further preferred that Ri in formula (I) and / or (Ia) stands for hydrogen and Y in formula (II) stands for a structure of the formula (III). It is likewise preferred that R6 and R7 in formula (III) each independently of one another stand for hydrogen or C1-C12-alkyl, particularly preferably for hydrogen or C1-C12-alkyl and very particularly preferably for hydrogen or methyl. This applies in particular if Ri in formula (I) and / or (Ia) stands for hydrogen and Y in formula (II) stands for a structure of the formula (III).

[0133] It is also preferred that X in formula (III) represents isopropylidene. This applies in particular if R 1 in formula (I) and / or (Ia) represents hydrogen, Y in formula (II) represents a structure of formula (III), and R 6 and R 7 in formula (III) each independently represent hydrogen or C 1 -C 12 -alkyl, particularly preferably hydrogen or C 1 -C 12 -alkyl, and most preferably hydrogen or methyl.

[0134] It is very 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 bisphenol A.

[0135] The polyester carbonate blend according to the invention can be processed as such into moldings of all kinds. It can also be processed with other thermoplastics and / or polymer additives to form thermoplastic molding compositions, which are then molded into moldings. The moldings are further objects of the present invention. The polymer additives are preferably selected from the group consisting of flame retardants, anti-drip 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), flow promoters, phase compatibilizers, dyes and pigments, impact modifiers, and fillers and reinforcing materials.

[0136] The molded articles containing the polyester carbonate blend according to the invention can be produced, for example, by injection molding, extrusion, and blow molding. Another processing method is the production of molded parts by deep drawing from previously produced sheets or films. Brief description of the figures:

[0137] Figure 1: Detail from the 13 C-NMR spectra of comparative example 2 at different reaction times

[0138] Figure 2: Detail from a 13 C-NMR spectrum of a commercial product included

[0139] Isophthalic acid / terephthalic acid resorcinol ester blocks and BPA, manufactured with

[0140] Interfacial processes

[0141] Figure 3: Detail from the 13 C-NMR spectra of Example 1 according to the invention at different reaction times

[0142] Figure 4: Schematic representation of the experimental setup of Example 5 according to the invention

[0143] Explanation of reference symbols:

[0144] 1 twin-screw extruder

[0145] 2 stirred tanks

[0146] 3.1 Gear pump

[0147] 3.2 Gear pump

[0148] 4 static mixers

[0149] 5 Vacuum pump

[0150] 6 Vacuum pump

[0151] 7 Capacitor

[0152] 8 Capacitor

[0153] 9 Water bath

[0154] 10 Strand pelletizer a to k extruder housing

[0155] Figure 5: schematic representation of the experimental setup of Examples 6 and 7 according to the invention. Explanation of the reference symbols:

[0156] 1 twin-screw extruder

[0157] 2 loss-in-weight dosing scales

[0158] 5 Vacuum pump

[0159] 6 Vacuum pump

[0160] 7 Capacitor

[0161] 8 Capacitor

[0162] 9 Water bath

[0163] 10 Strand pelletizer a to k Extruder housing examples

[0164] Materials used:

[0165] Terephthalic acid: for synthesis, CAS 100-21-0, Bernd Kraft Duisburg

[0166] Isophthalic acid: 99%, CAS 121-91-5, Sigma-Aldrich

[0167] Resorcinol: 99%, CAS 108-46-3, ABCR

[0168] Diphenyl carbonate: 99.5%, CAS 102-09-0; Acres Organics, Geel, Belgium, abbreviated as DPC

[0169] 4-Dimethylaminopyridine:; >98.0%; purum; CAS 1122-58-3; Sigma-Aldrich, Munich, Germany, abbreviated as DMAP

[0170] Tetrabutylphosphonium acetate (TBPAc): CAS-34430-94-9, manufactured according to Angewandte Chemie, International Edition, Vol. 48, Issue: 40, 7398-7401; 2009

[0171] Sodium benzoate: > 99%, CAS 532-32-1, Sigma-Aldrich

[0172] (3',4'-Epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate; CAS: 2386-87-0; Sigma-Aldrich, Munich, Germany

[0173] ADK Stab 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

[0174] Preparation of oligoester 1 :

[0175] 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 0.054 g

[0176] Tetrabutylphosphonium acetate (300 ppm), placed in a flask with a short path separator.

[0177] The mixture was freed of oxygen by evacuating four times and venting with nitrogen. The mixture was melted and heated to 200 °C at atmospheric pressure with stirring. A suspension formed because the terephthalic acid initially did not dissolve in the melt. The mixture was stirred at this temperature for approximately 3 hours. Carbon dioxide was released during this process. The mixture was slowly heated to 240 °C. Phenol distilled off during this process. The mixture was stirred at 240 °C for approximately 1 hour. Finally, stirring was continued for a further half hour at 260 °C. After gas evolution had ceased, the reaction mixture was cooled to 210 °C and the pressure reduced. The pressure was gradually reduced to 60 mbar over a period of 45 minutes. The temperature was raised to 230 °C and stirred at this temperature for half an hour. The temperature was then 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.

[0178] Preparation of oligoester 2:

[0179] The synthesis of the oligoester was carried out in principle as for oligoester 1.

[0180] Deviating from this, 62.31 g (0.375 mol) of terephthalic acid, 62.31 g (0.375 mol) of isophthalic acid, 86.70 g (0.7875 mol) of resorcinol, 329.37 g (1.5375 mol) of diphenyl carbonate as well as 0.216 g of DMAP (4-dimethylaminopyridine; 400 ppm based on the starting materials) and 0.162 g of tetrabutylphosphonium acetate (300 ppm) were placed in a flask with a short-path separator.

[0181] The maximum temperature was 245°C bath temperature and replaced the 260°C stage with the same holding time.

[0182] The remaining experimental procedure was analogous to the preparation of oligoester 1.

[0183] Preparation of oligoester 3 :

[0184] The synthesis of oligoester 3 was carried out in principle in the same way as that of oligoester 1.

[0185] Deviating from this, 62.31 g (0.375 mol) of terephthalic acid, 62.31 g (0.375 mol) of isophthalic acid, 107.37 g (0.975 mol) of resorcinol, 369.53 g (1.725 mol) of diphenyl carbonate as well as 0.24 g of DMAP (4-dimethylaminopyridine; 400 ppm based on the starting materials) and 0.18 g of tetrabutylphosphonium acetate (300 ppm) were placed in a flask with a short-path separator.

[0186] The maximum temperature was 245°C bath temperature and replaced the 260°C stage with the same holding time.

[0187] The remaining experimental procedure was analogous to the preparation of oligoester 1.

[0188] Table 1

[0189] 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 polyestercarbonate. 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 taken off directly at the outlet of the first horizontal reactor. The oligocarbonate has a phenolic end group content of 0.16% by weight.

[0190] Polycarbonate: linear bisphenol A polycarbonate with phenyl end groups with an MVR of 13 g / 20 min according to ISO 1133.

[0191] Analytical methods:

[0192] Solution viscosity:

[0193] 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 / l at 25 °C using an Ubbelohde viscometer.

[0194] GPC:

[0195] Molecular weights were determined using gel permeation chromatography with dichloromethane as the eluent. BPA polycarbonate was used as the standard. The signal from the refractive index detector (RID) was used. The corresponding method is defined under No. 2301-0257502-09D from Currenta GmbH & Co. OHG, which can be requested from Currenta at any time.

[0196] Determination of the content of phenolic OH end groups:

[0197] By infrared spectroscopy: The polyester carbonate, dissolved in dichloromethane (2 g / 50 ml; 1 mm quartz cuvette), was analyzed in a Thermo Fisher Scientific Nicolet iS 10 FT infrared spectrometer. The content of phenolic OH end groups was determined by evaluating the band at wavenumber 3583 cm" 1 Determined by H-NMR spectroscopy: The measurement was performed in dichloromethane using tetramethylsiloxane as an internal standard. The OH group content is given in wt.% relative to the oligomer. For evaluation, the OH group signal was integrated and related to the oligomer signals. Typically, the OH group resonance of the oligomer lies between 5.3 and 5.6 ppm. (However, those skilled in the art are aware that OH signals in NMR can shift depending on conditions such as the water content in the solvent.)

[0198] 13 C NMR spectroscopy:

[0199] The linking of isophthalic acid and / or terephthalic acid units and bisphenol A (see chemical formula (VIIx)) was achieved via 13 C-NMR spectroscopy has confirmed this. It will be referred to below as IPS / TPS-BPA ester. The bond between the isophthalic acid and / or terephthalic acid units and resorcinol has also been demonstrated (see chemical formula (lax)). It will be referred to below as IPS-TPS-resorcinol ester.

[0200] 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 acid and / or terephthalic acid resorcinol ester showed a signal at approximately 163-164 ppm.

[0201] The measurement was performed on a Bruker Avance III HD 600 MHz NMR spectrometer. The measurement was carried out in CDCl, using tetramethylsilane as the standard. The ratio of the different groups was determined by integrating the corresponding signals (ratio of the areas to each other).

[0202] The glass transition temperature (Tg) was determined by differential scanning calorimetry (DSC) according to 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 inflection point in the second heating process.

[0203] Preparation of a model ester compound from BPA and terephthalic acid / isophthalic acid

[0204] 21.9 mmol of BPA and a total of 21.9 mmol of the diphenyl esters of terephthalic acid and isophthalic acid were placed in a multi-necked round-bottom flask. 2.4 mg of tetrabutylphosphonium acetate was added, corresponding to 0.02% of the total mass. The contents of the flask were freed of oxygen by evacuating four times and inerting with nitrogen. The mixture was heated to 200°C with constant stirring. Condensate formation occurred continuously. With increasing phenol formation, the initially cloudy, liquid mixture became increasingly clear. An orange color appeared, which increased in intensity as the temperature rose to 230°C. Approximately 80 minutes after the start of the reaction, the pressure was reduced to 10 to 100 mbar 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

[0205] This substance was prepared to clearly identify the signal of the ester carbon atom, which characterizes the ester of BPA with terephthalic acid or isophthalic acid. It was shown that the corresponding signal lies between 164.2 and 164.5 ppm.

[0206] Comparison example 1

[0207] 8g of oligoester 1 and 32g of the oligocarbonate described above were placed in a multi-neck flask.

[0208] The contents of the flask were freed of oxygen by four evacuations and inerting with nitrogen. The mixture was immersed in a metal bath at 300°C. As soon as possible, the melt was homogenized using a stirrer within 15 minutes. The stirring speed was then set to 280-400 rpm and the pressure was quickly reduced to the technically feasible minimum, which must be at least <3 mbar.

[0209] 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 described conditions. After another 10 minutes, the heating bath temperature was increased to 335°C under the described conditions. 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, 1 C); low intensity; IPS-TPS-resorcinol ester C atom (ratio approx. 3.8:1)

[0210] Comparative Example 1 shows that, surprisingly, under the chosen reaction conditions, an almost complete transesterification towards the IPS / TPS-BPA ester occurs. The high intensity of the corresponding signal in the 13The C NMR spectrum confirms this. Only a small amount of IPS / TPS resorcinol ester is present. Comparative Example 2

[0211] Starting material weight: 4 g of oligoester 1 and 36 g of polycarbonate were placed in a multi-neck flask. The procedure was identical to Comparative Example 1.

[0212] Sample directly after melting: cloudy melt

[0213] 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, 1 C); high intensity; IPS-TPS-resorcinol ester C-atom (ratio approx. 1:13)

[0214] Sample after 10 min: cloudy melt

[0215] 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, 1 C); high intensity; IPS-TPS-resorcinol ester C-atom (ratio approx. 1:10)

[0216] Sample after 20 min (after increasing the temperature from 320 to 335 °C): transparent melt

[0217] 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, 1 C); low intensity; IPS-TPS-resorcinol ester C atom (ratio approx. 6:1).

[0218] Sample after 30 min: transparent melt

[0219] 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, 1 C); very low intensity; IPS-TPS-resorcinol ester C atom (ratio approx. 10:1).

[0220] The samples taken at 0 (immediately after melting) and after 10 minutes show that virtually no transesterification has occurred. The cloudy melt further demonstrates that the aromatic oligoester and the aromatic polycarbonate do not mix transparently, i.e., a phase mixture of two independent polymer phases is formed.

[0221] The samples taken after 20 and 30 minutes, however, demonstrate virtually complete transesterification. The sample melts are transparent in this case, indicating a uniform polymer phase.

[0222] In Comparative Example 1, an oligocarbonate with a relatively high OH end group content was used. This product therefore exhibits higher reactivity than the high-molecular-weight polycarbonate (with a lower content of phenolic OH groups) used in Comparative Example 2. It was therefore all the more surprising that virtually complete transesterification also occurred in this case. The production of a uniform copolymer at low temperatures appears impossible, since both polymer phases exist side by side without any reaction occurring. At higher temperatures, however, complete transesterification occurs without any significant amount of IPS-TPS resorcinol ester being present.

[0223] The 13C-NMR spectra at different sampling times are shown in Figure 1.

[0224] Comparison example 3

[0225] Educt weight: 4g of oligoester 1 and 36g of oligocarbonate were placed in a multi-neck flask.

[0226] The contents of the flask were freed of oxygen by four evacuations and inerting with nitrogen. The mixture was immersed in a metal bath at 300°C. As soon as possible, the melt was homogenized using a stirrer within 15 minutes. The stirring speed was then set to 280-400 rpm and the pressure was quickly reduced to the technically feasible minimum, which must be at least <3 mbar.

[0227] In the further course, a significantly increasing melt viscosity and slight condensate separation were observed.

[0228] After 30 minutes, the highly viscous, transparent, greenish to orange product was removed.

[0229] Sample after 5 min:

[0230] 13 C-NMR (600 MHz): 164.2–164.5 ppm (m, 1 C); medium intensity; IPS / TPS-BPA ester C atom;

[0231] 163.6-163.8 ppm (m, 1 C); medium to high intensity; IPS-TPS resorcinol ester C atom (ratio approx. 1:1.7)

[0232] Sample after 15 min:

[0233] 13 C-NMR (600 MHz): 164.2–164.5 ppm (m, 1 C); high intensity; IPS / TPS-BPA ester C atom;

[0234] 163.6-163.8 ppm (m, 1 C); medium-low intensity; IPS-TPS resorcinol ester C-atom (ratio approx. 1.7:1)

[0235] Sample after 30 min:

[0236] 13 C-NMR (600 MHz): 164.2–164.5 ppm (m, 1 C); high intensity; IPS / TPS-BPA ester C atom;

[0237] 163.6-163.8 ppm (m, 1 C); low intensity; IPS-TPS resorcinol ester C atom (ratio approx. 3.8:1). This comparative example was designed to test whether it is possible to produce the desired product with high amounts of IPS-TPS resorcinol ester by lowering the temperature. However, it was found that after just 5 minutes, a significant amount of BPA ester was present, which continued to increase over the course of the reaction. Therefore, it is doubtful whether the desired product can be produced by targeted temperature control.

[0238] Inventive Example 1

[0239] Educt weight: 8g of oligoester 2 and 2g of oligocarbonate were placed in a multi-neck flask.

[0240] The contents of the flask were freed of oxygen by four evacuations and inerting with nitrogen. The mixture was immersed in a metal bath at 310°C. As soon as possible, the melt was homogenized using a stirrer within 15 minutes. The stirring speed was then set to 280-400 rpm and the pressure was quickly reduced to the technically feasible minimum, which must be at least <3 mbar. A significant increase in the melt viscosity and slight condensate separation were observed during the subsequent process.

[0241] After 30 minutes, the highly viscous, transparent, greenish to orange product was removed (intermediate samples were taken after 5 and 15 minutes).

[0242] Sample after 5 min:

[0243] 13C-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, 1 C); high intensity; IPS-TPS-resorcinol ester C atom (ratio approx. 1:3.5)

[0244] The signal intensities of sample 15 min and sample 30 min were practically unchanged compared to sample 5 min.

[0245] This demonstrates that it is possible to obtain a high amount of IPS-TPS resorcinol ester in this case. The amount of resorcinol ester does not change significantly over the course of the reaction.

[0246] The 13 C-NMR spectra at different sampling times are shown in Figure 2.

[0247] Inventive Example 2

[0248] Educt weight: 8g of oligoester 3 and 2g of oligocarbonate were

[0249] The reaction mixture was placed in a multi-neck flask. The procedure was identical to "Inventive Example 1."

[0250] Sample after 5 min: 13C-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, 1 C); high intensity; IPS-TPS-resorcinol ester C atom (ratio approx. 1:11.5).

[0251] The signal intensities of sample 15 min and sample 30 min were practically unchanged compared to sample 5 min.

[0252] This demonstrates that it is possible to obtain a high amount of IPS-TPS resorcinol ester in this case as well. The amount of resorcinol ester does not change significantly over the course of the reaction.

[0253] Inventive Example 3

[0254] Starting material weight: 1.875 g of the product from the experiment described in Example 1 according to the invention and 13.125 g of the polycarbonate were placed in a multi-necked flask to achieve an oligoester mass fraction of 10%. 7.5 mg of 3',4'-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate and 15 mg of ADK Stab. PEP-36 were added. The contents of the flask were freed of oxygen by purging 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 was then taken (0 min). The stirring speed was then set to 280-400 rpm and the pressure was quickly reduced to the technically possible minimum, which must be at least <3 mbar. In the further course, a significantly increasing melt viscosity and slight condensate separation were observed.

[0255] After 30 minutes, the highly viscous, transparent, greenish to orange product was removed (intermediate samples were taken after 5 and 15 minutes).

[0256] Sample after 0 min (after melting):

[0257] 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, 1 C); high intensity; IPS-TPS-resorcinol ester C atom (ratio approx. 1:3)

[0258] Sample after 5 min:

[0259] 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, 1 C); high intensity; IPS-TPS-resorcinol ester C atom (ratio approx. 1:2).

[0260] Sample after 15 min: 13 C-NMR (600 MHz): 164.2–164.5 ppm (m, 1 C); medium intensity; IPS / TPS-BPA ester C atom;

[0261] 163.6-163.8 ppm (m, 1 C); medium-high intensity; IPS-TPS resorcinol ester C atom (ratio approx. 1:1.4).

[0262] Sample after 30 min:

[0263] 13 C-NMR (600 MHz): 164.2–164.5 ppm (m, 1 C); medium intensity; IPS / TPS-BPA ester C atom;

[0264] 163.6-163.8 ppm (m, 1 C); medium intensity; IPS-TPS resorcinol ester C atom (ratio approx. 1:1). The eta rel of this sample was 1.309.

[0265] The 13 C-NMR spectra show that only after a reaction time of 30 minutes does the proportion of IPS / TPS-BPA ester become 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. Surprisingly, this example shows, compared to the comparative examples, that the melt transesterifies relatively slowly. Even though the proportion of BPA polycarbonate is high, surprisingly only a small proportion transesterifies to the IPS / TPS-BPA ester.

[0266] Inventive Example 4

[0267] Starting material weight: 1.875 g of the product from the experiment described in Inventive Example 2 and 13.125 g of the polycarbonate were placed in a multi-neck flask, achieving a mass fraction of the oligoester of 10%. 7.5 mg of 3',4'-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate and 15 mg of ADK Stab. PEP-36 were added. The procedure was identical to "Inventive Example 3."

[0268] Sample after 0 min (after melting):

[0269] 13 C-NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); low intensity; IPS / TPS-BPA ester C atom;

[0270] 163.6-163.8 ppm (m, 1 C); high intensity; IPS-TPS resorcinol ester C atom (ratio approx. 1:4.3).

[0271] Sample after 5 min:

[0272] 13 C-NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); low intensity; IPS / TPS-BPA ester C atom;

[0273] 163.6-163.8 ppm (m, 1 C); high intensity; IPS-TPS resorcinol ester C-atom (ratio approx. 1:4)

[0274] Sample after 15 min:

[0275] 13 C-NMR (600 MHz): 164.2-164.5 ppm (m, 1 C); low intensity; IPS / TPS-BPA ester C atom;

[0276] 163.6-163.8 ppm (m, 1 C); high intensity; IPS-TPS resorcinol ester C atom (ratio approx. 1:2.5)

[0277] Sample after 30 min: 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, 1 C); medium intensity; IPS-TPS-resorcinol ester C atom (ratio approx. 1:2.1)

[0278] In this example, the tendency to transesterification is even lower. Surprisingly, even after 30 minutes, the proportion of IPS-TPS resorcinol ester predominates.

[0279] Inventive Example 5

[0280] For Example 5 according to the invention, the experimental setup shown schematically in Figure 4 was used.

[0281] 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). Furthermore, 2.84 g of dimethylaminopyridine and 2.13 g of tetrabutylphosphonium acetate were added to the reaction mixture. The tank was freed of oxygen by repeated evacuation and inerting with nitrogen. The reaction mixture was melted under atmospheric pressure, and the liquid reaction mixture was pumped back into the stirred tank (2) via the static mixer (4) using the gear pump (3.1). The temperature of the tank was gradually increased to 245 °C. Carbon dioxide was released and removed from the reaction vessel. After carbon dioxide evolution had ceased and the reaction mixture became clear, the vessel was cooled to 210 °C and the pressure was gradually reduced to 60 mbar over a period of 30 minutes. Phenol was continuously removed from the reaction mixture.A holding phase of 30 minutes followed. The temperature was then increased to 230°C and held constant for another 30 minutes. The temperature was then increased to 245°C and held constant for another 30 minutes. The best possible vacuum (< 1 mbar) was then applied and maintained under the described conditions for another 30 minutes.

[0282] 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 rotary stirrer at 17.5 rpm and conveyed by the gear pump (3.1) through the circulation line with the static mixer (4). The melt was circulated in this way for 75 minutes. The polymer melt was then continuously conveyed by a second gear pump (3.2) at a throughput of 1.2 kg / h to the twin-screw extruder (1) (type ZSE 27 MAXX with 11 barrels from Leistritz Extrusionstechnik GmbH, Nuremberg). The extruder barrels are designated in Figure 4 with the letters "a" to "k." The extruder was operated at 100 rpm at a barrel temperature of 310 °C. The melt was fed into the fourth barrel (d) of the extruder. Reverse degassing at 25 mbar absolute pressure was performed via the first barrel (a) of the extruder.A vacuum of 25 mbara was applied to the fifth barrel of the extruder (e), and a vacuum of 3-5 mbara was applied to barrels (g), (i), and (j). The polymer melt was extruded at a melt temperature of 311°C, fed into a water bath (9), and pelletized using a strand pelletizer (10). The polymer sample had a Mn of 3750 g / mol and a Mw of 8300 g / mol (RID).

[0283] Inventive Example 6

[0284] The experimental setup for Example 6 according to the invention is shown in Figure 5.

[0285] 468.75 g of the granulated product from Example 5 according to the invention, 3281.25 g of polycarbonate as well as 1.875 g of epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate and 3.750 g of ADK Stab PEP 36 were mixed in a drum wheel mixer for 30 minutes.

[0286] The mixture was fed continuously via the loss-in-weight feeder (2) at a throughput of 2 kg / h into the feed barrel (a) of the twin-screw extruder (1) (type ZSE 27 MAXX with 11 barrels from Leistritz Extrusionstechnik GmbH, Nuremberg) and extruded at 150 rpm. The extruder barrels are designated in Figure 5 with the letters "a" to "k". The mixture was extruded at a barrel temperature of 160°C for barrel (b), 240°C for barrel (c), 300°C for barrel (d), and 320°C for barrels (f) to (k) with a melt temperature of 329°C, fed into the water bath (9), and pelletized using the strand pelletizer (10). The extruder has venting zones on barrels (e), (g), (i), and (j). These were operated under atmospheric pressure.

[0287] The product has the following analytical data: transparent granules, Eta rel: 1.225, Tg: 143 °C, the 13 C spectrum shows predominantly IPS-TPS resorcinol esters (ratio approx. 1:2.6).

[0288] Inventive Example 7

[0289] The experimental setup for Example 7 according to the invention is shown in Figure 5.

[0290] The mixture from Example 6 according to the invention was fed continuously via the differential dosing scale (2) at a throughput of 1.4 kg / h into the feed barrel (a) of the twin-screw extruder (1) (type ZSE 27 MAXX with 11 barrels from Leistritz Extrusionstechnik GmbH, Nuremberg) and extruded at 100 rpm. The extruder barrels are designated in Figure 5 by the letters "a" to "k". The mixture was extruded at a barrel temperature of 160°C for barrel (b), 240°C for barrel (c), 300°C for barrel (d), and 320°C for barrels (f) to (k) with a melt temperature of 328°C, fed into the water bath (9), and granulated using the strand granulator (10). A vacuum of 32 mbara was applied to the extruder barrel (e) and a vacuum of < 1 mbara was applied to the barrels (g), (i) and (j). The product has the following analytical data: transparent granules, eta rel: 1.230, Tg: 145 °C, the 13C spectrum shows predominantly IPS-TPS resorcinol esters (ratio approx. 1:2.6).

[0291] The extrusion tests show that it is possible to produce the desired polyester carbonate using the process according to the invention, which still contains the desired resorcinol ester linkages to a high degree.

Claims

Patent claims:

1. Method for producing a polyester carbonate prepolymer, comprising the steps (a) Providing an oligoester comprising structures of 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 wt% of the oligoester from step (a) with 35 to 5 wt% of the oligocarbonate and / or polycarbonate from step (b), where the wt% refers to the sum of the weights of the oligoester from step (a) and of the oligocarbonate and / or polycarbonate from step (b), by means of a melt condensation reaction to obtain a polyester carbonate prepolymer.

2. Method according to claim 1, characterized in that the oligoester of step (a) has a number-averaged 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.

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

5. 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 “*” specify the positions at which the ester groups are incorporated into the polyester carbonate blend, (B) Carbonate groups of the formula (II) in which Y independently represents each of the structures of 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 bond, -CO- , -O- , -S-, Ci- to C ( , -Alkylene. C2- to Cs-alkylidenes, C to Cio-cycloalkylidenes or for Ce- to Ci2-arylene, which may optionally be condensed with aromatic rings containing further heteroatoms, stands, (IV) (V) (VI), where in these formulas (IV) to (VI) R 3where each represents Ci-C4-alkyl, aralkyl or aryl, preferably methyl or phenyl, most preferably methyl, and the “*” indicates the positions at which formulas (III), (IV), (V) or (VI) attach to the carbonate group in formula (II), m indicates the average number of repeating units and the positions at which the carbonate groups are incorporated into the polyester carbonate blend, wherein at least some of the ester groups (A) are directly linked to at least some of the carbonate groups (B) via formula (VII), wherein (VII), in which Y has the meanings described above for (B) and (A) stands for attachment to the ester group (A) and (B) stands for attachment to the carbonate group (B), characterized in that the polyester carbonate prepolymer contains more mol% of carbon atoms, as indicated by an arrow in formula (1a), than mol% of carbon atoms, as indicated by an arrow in formula (VII), have.

6. Method for producing a polyester carbonate blend, comprising the steps (i) Providing a polyester carbonate prepolymer according to claim 5 or produced according to the method according to any one of claims 1 to 4, (ii) Providing a polycarbonate with a weight-mean 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 the eluent, (iii) Transferring the polyester carbonate prepolymer from step (i) and the polycarbonate from step (ii) into a molten state and mixing in the molten state 5 to 25 wt.% of the polyester carbonate prepolymer with 95 to 75 wt.% of the polycarbonate, where the wt% refer to the sum of the weight of polyester carbonate prepolymer from step (i) and of polycarbonate from step (ii) to obtain a polyester carbonate blend.

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

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

9. Polyester carbonate blend, comprehensive (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 at which the ester groups are incorporated into the polyester carbonate blend, (B) Carbonate groups of the formula (II) in which Y independently represents each of the structures of 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 bond, -CO- , -O- , -S-, Ci- to C ( , -Alkylene. C2- to Cs-alkylidenes, C to Cio-cycloalkylidenes or for Ce- to Ci2-arylene, which may optionally be condensed with aromatic rings containing further heteroatoms, stands, (IV) (V) (VI), where in these formulas (IV) to (VI) R 3 where each represents Ci-C4-alkyl, aralkyl or aryl, preferably methyl or phenyl, most preferably methyl, and the “*” indicates the positions at which formulas (III), (IV), (V) or (VI) link to the carbonate group in formula (II), m indicates the average number of repeating units, and the respective positions at which the carbonate groups are incorporated into the polyester carbonate blend, wherein at least some of the ester groups (A) are directly linked to at least some of the carbonate groups (B) via formula (VII), wherein (VII), in which Y has the meanings described above for (B) and (A) stands for attachment to the ester group (A) and (B) stands for attachment to the carbonate group (B), wherein 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 indicated by an arrow in formula (1a), than mol% of carbon atoms, as indicated by an arrow in formula (VII), (1a), where Ri, n and “*” are the above-mentioned have meanings and where (A), Y and (B) have the meanings mentioned above.

10. Polyester carbonate blend according to claim 9, characterized in that the polyester carbonate 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 polyester carbonate prepolymer according to claim 5 or produced according to the method according to any one of claims 1 to 4 for compatibilizing an oligoester comprising structures of 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.

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

13. Method for producing a polyester carbonate blend according to one of claims 6 to 8 or 12 or a polyester carbonate blend according to one of claims 9 to 10 or 12, characterized in that Y in formula (II) represents a structure of formula (III). A process for producing a polyester carbonate blend according to one of claims 6 to 8 or 12 to 13, or a polyester carbonate blend according to one of claims 9 to 10 or 12 to 13, characterized in that R6 and R7 in formula (III) each independently represent hydrogen or Ci-Cn alkyl, particularly preferably hydrogen or C'i-Cx alkyl, and most preferably hydrogen or methyl. A shaped body comprising the polyester carbonate blend according to one of claims 9 to 10 or 12 to 14.

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