CN117500859A

CN117500859A - Oligoesters comprising resorcinol and isophthalic acid and/or terephthalic acid, corresponding polyester carbonates and their preparation

Info

Publication number: CN117500859A
Application number: CN202280042650.5A
Authority: CN
Inventors: A·迈耶; L·F·舒尔茨; T·平斯特; U·利森菲尔德; D·欣兹曼
Original assignee: Covestro Deutschland AG
Current assignee: Covestro Deutschland AG
Priority date: 2021-06-15
Filing date: 2022-06-10
Publication date: 2024-02-02
Also published as: WO2023208897A1

Abstract

The present invention relates to a mixture comprising oligoesters, a polyestercarbonate comprising ester blocks, and a process for preparing a polyestercarbonate comprising ester blocks by melt transesterification.

Description

Oligoesters comprising resorcinol and isophthalic acid and/or terephthalic acid, corresponding polyester carbonates and their preparation

The present invention relates to a mixture comprising oligoesters, to a polyester carbonate comprising ester blocks, and to a process for preparing a polyester carbonate comprising ester blocks.

Aromatic polyester carbonates are known to have good properties in terms of mechanical properties and resistance to thermal deformation. Specific polyester carbonates are also known to have high weatherability, especially when they contain ester blocks formed from aromatic diacids and resorcinol.

In particular, polyester carbonates containing ester blocks formed from isophthalic acid and/or terephthalic acid and resorcinol are known to have good weatherability. These materials are of particular interest because they do not require any lacquering to protect them from harmful weathering, especially from ultraviolet light. The ester structure formed from resorcinol and isophthalic acid and/or terephthalic acid may undergo a so-called photofries rearrangement upon contact with ultraviolet light. Where a hydroxybenzophenone structure is formed which is incorporated into the polymer chain. Hydroxybenzophenones are known to have ultraviolet absorbing properties. This demonstrates its good weatherability. This fact is described, for example, in US20030050400 A1. In contrast, the use of an ultraviolet absorber instead is much less effective because most of the ultraviolet absorber can accumulate in the body. In particular, the concentration of the ultraviolet absorber at the surface, which has to be protected from ultraviolet light, is relatively low. The person skilled in the art will be faced with further disadvantages if he wants to use a higher concentration of uv absorber. For example, low molecular weight compounds can reduce mechanical properties, especially at higher concentrations. This is undesirable. In order to anchor higher concentrations of uv absorber in the surface, uv sensitive materials, such as polycarbonate, are usually protected by a paint layer with a high concentration of uv absorber. However, painting is an additional step which can create costs and is not always a preferred solution for sustainability reasons. In particular in the field of automotive exterior applications, it is advantageous if the material is inherently weather-resistant and complex lacquering can be dispensed with.

The polyester carbonates are produced in the prior art by the phase interface process. In this process, the aromatic diol and the OH-terminated ester block are condensed by phosgene. The OH-terminated ester blocks can likewise be prepared starting from aromatic diacids and aromatic diols by condensation with phosgene in solution. Such a process for preparing oligoesters and corresponding polyestercarbonates is described in WO 0026275A 1. This document describes, as a preferred polymer, a polyester carbonate of bisphenol A containing ester blocks formed from terephthalic acid/isophthalic acid. The preparation of the ester blocks is effected here starting from the acid chloride of the aromatic diacid and resorcinol in a methylene chloride/water mixture using aqueous NaOH. The polyester solution containing the hydroxyl-terminated ester blocks is transferred to a phosgenation reactor. In a preferred case, an alkaline bisphenol A solution is introduced and the reaction partner is reacted with phosgene.

Methods based on the melt transesterification process known for polycarbonates are known and have the advantage that difficult-to-handle starting materials, such as phosgene, can be avoided. Furthermore, they have the great advantage that solvents can be dispensed with. It is therefore industrially advantageous to prepare polyestercarbonates by the melt transesterification process. However, this approach is also challenging. For example, highly reactive acid chlorides are difficult to replace with other starting materials. Transesterification processes generally have a longer residence time in the corresponding reactor. In this case, decomposition products are often formed due to the high temperatures, which adversely affect the product quality. Since the melt transesterification process generally does not require complicated post-treatment steps, impurities including catalyst residues remain in the product. These all reduce the quality of the product.

Furthermore, polycarbonates produced by the melt transesterification process have a significantly higher hydroxyl-terminated end group content (phenolic OH group content) than the corresponding products from the phase interface process. These phenolic OH groups may be destroyed by the oxidation process, thereby degrading the product quality. This affects in particular the optical properties. However, it is important to obtain good optical properties, especially in cases where the product should be characterized by high inherent weatherability. Advantageously, therefore, the phenolic OH end group content is low. However, no teaching is made in this prior art regarding the mentioned polyestercarbonates, since the prior art only relates to the preparation of polyestercarbonates by phase interface reactions. Thus, the person skilled in the art does not know how to prepare such polyester carbonates with a low OH end group content by melt transesterification.

Since for the reasons mentioned above the reactivity of the reaction partner is low compared to the starting materials in the phase interface process, it is also not known how to prepare the abovementioned polyestercarbonates having high viscosity or molecular weight.

WO2005021616A1 describes the preparation of hydroxyl-terminated oligoester blocks in the melt. What is investigated here is how it is possible to achieve an OH end group content of the oligoester which is comparable to that obtainable in a process using a solvent. For this purpose, the effect of different catalysts and modes of operation (e.g. different temperatures and vacuum) was also tested. The molecular weight of the resulting oligoester is relatively low. Although oligoesters having phenoxy end groups are described herein, WO2005021616A1 does not describe the molecular weight distribution of the oligomers of the oligoesters. In addition, the oligoesters are subsequently condensed by the phase interface process to give polyestercarbonates. Thus, this document does not contain any teaching on how the end groups and/or oligomer distribution influence the preparation of polyester carbonates by melt transesterification.

An oligoester prepared by the melt transesterification process is described in WO 2006057810A 1, which is characterized in that it has a high proportion of terminal carboxyl groups. These carboxyl end groups are then used to incorporate the oligoester into the paint system. However, the free acids are relatively less reactive in the melt transesterification process for preparing polyester carbonates, and therefore these precursors are not suitable for the melt-based polyester carbonates mentioned. Therefore, the use in the melt transesterification process is also not described herein.

US20030050400A1 describes the preparation of oligomers from aromatic diacids and resorcinol. The purpose of US20030050400A1 is to provide OH-terminated units which can then be converted into polyester carbonates by the phase interface method. Similar to WO2005021616 A1, neither oligomer distribution, end group ratio nor its effect on melt transesterification of the oligoester is discussed herein.

Starting from this prior art, the object of the present invention is to overcome at least one disadvantage of the prior art. In particular, it is an object of the present invention to provide polyester carbonates comprising ester blocks based on isophthalic acid and/or terephthalic acid and resorcinol, which are obtainable by the melt transesterification process. It is preferred here to obtain polyester carbonates which have good processability and at the same time as low a phenolic OH end group content as possible. Thus, the polyester carbonates should preferably be weather-resistant and/or substantially yellowing-stable and/or have substantially no tendency to polymer degradation, for example due to oxidative degradation. It is also preferred that no starting materials which present challenges in handling, such as phosgene, are used in the preparation of the polyester carbonates.

At least one, preferably all, of the above objects are achieved by the present invention. Surprisingly, it has been found that processable polyester carbonates can be provided by the melt transesterification process only when the oligoesters have a specific end group content and a specific proportion of small oligomers. Polyester carbonates having a high molecular weight (but not too high) and at the same time a sufficiently low phenolic OH end group content to give polyester carbonates with a high stability to degradation, for example, can only be obtained by melt transesterification when a mixture comprising oligoesters having up to 0.5% by weight of OH end groups, for example phenolic OH end groups, in which the groups in the end groups are essentially specific aromatic groups, preferably phenyl groups, is used and the proportion of oligomers having a molecular weight of less than 1000g/mol is low. The use of specific oligocarbonates results in the acquisition of novel polyestercarbonates in which a high proportion of isophthalic acid and/or terephthalic acid groups are directly bonded to the carbonate blocks. In the prior art, oligoesters having as high an OH end group content as possible are used. This automatically results in the diols used (e.g. resorcinol) forming the end groups of these oligoesters. They then bond to the carbonate blocks, thereby creating, for example, carbonate-resorcinol-linkages. In contrast, the oligoester groups according to the invention are essentially terminated by specific aromatic esters of isophthalic acid and/or terephthalic acid. This results in polyester carbonates having novel bonds through isophthalic acid and/or terephthalic acid. By providing specific oligoesters, it is thus possible to obtain polyester carbonates from oligocarbonates and oligoester blocks by melt transesterification, which have good properties for the above-mentioned desired purposes.

Thus, according to the present invention there is provided a mixture comprising an oligoester of formula (1)

Wherein the method comprises the steps of

Each R ₁ Each independently of the others is a hydrogen atom, a halogen or an alkyl group having 1 to 4 carbon atoms,

each q is independently of the others 0 or 1,

if q=1: each Z is independently of the others-H or an aromatic radical of the formula (2 a)

Wherein R is ₂ ' is hydrogen or-COOCH ₃ And "×" represents the position where formula (2 a) is bonded to the oxygen atom in formula (1),

if q=0: each Z is independently of the others an aromatic radical of the formula (2)

Wherein R is ₂ Is hydrogen or-COOCH ₃ And "×" represents the position where formula (2) is bonded to the oxygen atom in formula (1), an

p represents the number of repeating units and,

characterized in that at most 0.5 wt.% of the Z groups, relative to the mixture, are hydrogen and that the percentage of oligomers in the mixture having a molecular weight of less than 1000g/mol, is less than 12%, preferably less than 10%, wherein the percentage of oligomers is determined by the ratio of the area below the range of 1000g/mol below the molecular weight distribution curve of the mixture (from gel permeation chromatography) based on the refractive index signal to the total area below the molecular weight distribution curve, and wherein gel permeation chromatography is performed with bisphenol a polycarbonate standard in methylene chloride.

According to the invention, the expression "mixture comprising the oligoester of formula (1)" is understood to mean that the mixture essentially consists of the oligoester of formula (1). This preferably means that at least 80% by weight, more preferably at least 90% by weight, most preferably at least 95% by weight of the mixture consists of the oligoester of formula (1). However, as a result of the preparation, it cannot be excluded that the mixture also comprises a proportion of oligoesters of formula (1), but in which at least one of q=0 and in which case Z is hydrogen at the chain end of the oligoester of q=0. In this case, R ₁ And p has the definition given above. This means that the oligoester is terminated at least on one side by isophthalic acid/terephthalic acid (-COOH as end group).

In the case of the oligoesters of formula (1) in which at least one of q=0 and at which the end of the oligoester of Z at q=0 is hydrogen, these OH end groups (-COOH end groups) are not included in the defined weight% of OH end groups (by Z in formula (1)) in the mixtures according to the invention. Preferably, the proportion of-COOH end groups in the mixture according to the invention (in the case of at least one oligoester of formula (1) with q=0 and Z being hydrogen at the chain end of q=0) is at most 10% by weight, more preferably at most 8% by weight, very particularly preferably at most 5% by weight, most preferably at most 2% by weight, based on the total weight of the mixture. Those skilled in the art know how to determine these-COOH end groups. In particular, it can pass through C ¹³ -NMR measurement to determine carbon atoms as part of the acid end groups. For this purpose, deuterated DMSO is in particular a suitable solvent. The carbon atoms as part of the acid end groups should generally be in the range of 160 to 170ppm,in particular 163 to 169 ppm. Preferably according to the invention, the content of formula (1) wherein at least one of q=0 and Z is hydrogen at the chain end of the oligoester of q=0 is low in the mixture according to the invention.

Preferably according to the invention, the mixture contains in total at most 0.5 wt.%, preferably at most 0.45 wt.%, more preferably at most 0.4 wt.%, most preferably at most 0.35 wt.% OH end groups, based on the total weight of the mixture (preferably by ¹ H-NMR detection).

Preferably, R in formula (1) ₁ Is hydrogen. This means by R ₁ The substituted ring is preferably derived from resorcinol.

Preferably, R in formula (2) ₂ Is hydrogen. This means that R is present on it in formula (2) ₂ The radicals of (2) in combination with formula (1) are preferably phenyl isophthalate and/or phenyl terephthalate.

Also preferably, R in formula (2 a) ₂ ' is hydrogen. This means that R is present on it in formula (2 a) ₂ The combination of the' groups with formula (1) is preferably resorcinol phenyl carbonate.

Particularly preferably, R in formula (1) ₁ Is hydrogen, R in formula (2) ₂ Is hydrogen and R in formula (2 a) ₂ ' is hydrogen.

P in formula (1) represents the number of repeating units of the oligoester. p is preferably on average at least 4. More preferably, p in formula (1) averages at least 4 and at most 30, more preferably at least 5 and at most 27, most preferably at least 5 and at most 24. Particularly preferably, the oligomeric ester mixture has a number average molecular weight of from 1300g/mol to 6000g/mol, more preferably from 1400g/mol to 5500g/mol, most preferably from 1500g/mol to 5000 g/mol. The M is _n Preferably by gel permeation chromatography in methylene chloride with bisphenol a polycarbonate as standard. The molecular weights Mw (weight average) and Mn (number average) of the oligoesters or polyestercarbonates used according to the invention are determined, unless otherwise specified, by size exclusion chromatography (gel permeation chromatography GPC; calibration with BPA polycarbonate according to DIN 55672-1:2007-08). Calibration was performed using linear polycarbonates of known molecular weight distribution (e.g. from german PSS Polymer Standards Service GmbH). At the position ofThis was done using a sample from Lewkusen Currenta GmbH&Co.OHG methods 2301-0257502-09D (from German in 2009). Dichloromethane was used as eluent. The column combination is composed of a crosslinked styrene-divinylbenzene resin. GPC may comprise one or more commercially available GPC columns in series with each other for size exclusion chromatography, selected so that polymers, in particular weight average molecular weights M, are possible _w The molecular weight of the aromatic polycarbonate is sufficiently separated from 2000 to 100000 g/mol. The analytical column is typically 7.5mm in diameter and 300mm in length. The particle size of the column material is 3 μm to 20 μm.

The mixtures according to the invention are preferably characterized by R in formula (1) ₁ Is hydrogen, up to 0.4% by weight, based on the mixture, of Z groups are hydrogen, and the percentage of oligomers having a molecular weight of less than 1000g/mol is less than 10%.

The mixture according to the invention has at most 0.5 wt.%, preferably at most 0.45 wt.%, more preferably at most 0.4 wt.%, most preferably at most 0.35 wt.% of OH end groups (which means that Z in formula (1) is hydrogen), based on the total mixture. The OH end group content can be determined in a manner known to the person skilled in the art. The OH end group content is preferably determined by ¹ H-NMR measurement. This can be achieved, for example, with tetramethylsiloxane as an internal standard in methylene chloride. For this purpose, the area under the signal of the OH groups (generally 5.3 to 5.6 ppm) is expressed relative to the area of the other signals of the oligomer.

Surprisingly, it has been found that when the OH end group content of the mixture according to the invention is greater than 0.5% based on the total mixture, the reactivity of the oligoester mixture is so great that polyester carbonates with a relative solution viscosity which are no longer processable (i.e. generally ηrel higher than 1.35) are obtained by melt transesterification. Thus, the polyester carbonates obtained can only be processed with difficulty, for example by injection molding, to give molded articles. At the same time, many of the polyester carbonates thus obtained also have a high phenolic OH content. This often results in unstable polymers, which tend to degrade with temperature and/or light. If the OH end group content of the mixture according to the invention is at most 0.5% by weight, based on the entire mixture, polyester carbonates can be obtained in contrast which, owing to their molecular weight (measured as ηrel) and the resulting phenolic OH end group content thereof, are both good in terms of processability (for example by injection molding) and very stable to degradation.

It is preferred according to the present invention that the ratio of end groups of formula (1) wherein Z corresponds to formula (2 a) and/or formula (2) to end groups wherein Z is hydrogen (and q=1 in the end groups) is 10:1 to 2:1, more preferably 9:1 to 3:1, most preferably 8:1 to 4:1. The ratio of end groups can be determined in a manner known to the person skilled in the art. In particular, the ratio may be determined by ¹ H-NMR is preferably measured at least 700 MHz. This can be achieved, for example, with tetramethylsiloxane as an internal standard in methylene chloride. For this purpose, the area under the signal of the OH groups (typically 5.3 to 5.6 ppm) can be expressed relative to the area of the other signals of the oligomer. Depending on the overlap of peaks and the choice of building monomer of the oligoester according to the invention, it is also possible to express, for example, the area of the peak which should correspond to about 7.4ppm of phenyl end groups (2 protons) relative to the area of the peak which should correspond to 6.6 to 6.8ppm of resorcinol end groups (3 protons).

It has also surprisingly been found that the proportion of oligomers having a molecular weight of less than 1000g/mol in the mixture according to the invention must be less than 12%, preferably less than 11%, more preferably less than 10%, in order to substantially increase the molecular weight of the polyestercarbonates by melt transesterification. If the ratio is more than 12%, the reactivity of the oligoester mixture is insufficient to cause a sufficient increase in molecular weight. This means that the resulting polyester carbonates do not have the desired properties with respect to processability, mechanical properties and optical properties. According to the invention, the proportion of oligomers having a molecular weight of less than 1000g/mol is determined by the ratio of the area below the range of less than 1000g/mol below the molecular weight distribution curve (from gel permeation chromatography) of the mixture based on the refractive index signal to the total area below the molecular weight distribution curve. Here, gel permeation chromatography was performed with bisphenol a polycarbonate standards in methylene chloride (see also the exact description of gel permeation chromatography above). The curve of the refractive index signal vs. molecular weight can be integrated in a manner known to the person skilled in the art, in particular by GPC software. The area below the curve below 1000g/mol is expressed here with respect to the total area. Clearly, the Mn of the oligomeric ester mixture has an effect on the amount of oligomers having a molecular weight of less than 1000 g/mol. This means, on the one hand, that in the case of low Mn values of the oligoesters, a relatively narrow distribution of the molecular weight distribution will be present, whereby the proportion of oligomers having a molecular weight of less than 1000g/mol is less than 12%. On the other hand, this may also preferably mean that the oligoester has a relatively high Mn, so that the proportion of oligomers having a molecular weight of less than 1000g/mol is therefore less than 12%.

Preferably, the mixture according to the invention comprising the oligoesters of formula (1) in all the above preferences and in the form of a combination of preferences is prepared by a process in which

(i) Mixing at least isophthalic acid and/or terephthalic acid with a diol of formula (3) and at least one diaryl carbonate of formula (4), wherein

Wherein R is ₁ Is a hydrogen atom, a halogen or an alkyl group having 1 to 4 carbon atoms, preferably hydrogen, and wherein

Wherein R is ₂ Each independently of the other is hydrogen or-COOCH ₃ Preferably, the hydrogen is used,

(ii) Heating the mixture from step (i) in the presence of at least one catalyst, and

(iii) Applying a vacuum to the mixture from step (ii) to obtain a mixture comprising the oligoester.

Optionally, the process of the invention may also supplement step (iv), wherein the mixture comprising oligoesters obtained from step (iii) is precipitated. For this purpose, the mixture is preferably dissolved in methylene chloride. It is also preferred that it can then be precipitated in a non-solvent such as methanol. The precipitated mixture comprising the oligoester is subsequently separated from the non-solvent and optionally dried to obtain the mixture comprising the oligoester according to the invention. Step (iv) may be used when the proportion of oligomers in the mixture having a molecular weight of less than 1000g/mol is greater than 12%. The effect of precipitation is that low molecular weight oligomers remain in solution. The proportion of oligomers having a molecular weight of less than 1000g/mol in the mixture can thus be reduced.

Also optionally, the process according to the invention may optionally comprise, in addition to step (iv), a further step (v) in which the mixture comprising the oligoester obtained from step (iii) or from step (iv) is reacted with diphenyl diacid, preferably diphenyl isophthalate and/or diphenyl terephthalate. In particular, process step (v) may be employed when the OH end group content of the mixture comprising the oligoester obtained from step (iii) or step (iv) is greater than 0.5% by weight, based on the mixture. At least some of the OH end groups can be converted to phenoxy end groups (i.e., Z in formula (1) is phenyl) by additional reaction with diphenyl diacid. In this way, the OH end group content of the mixture comprising the oligoester can be reduced. Alternative step (v) for reducing the OH end group content is also known to the person skilled in the art. However, the step (v) is particularly preferred because the introduction of the end groups results in reactivity during the subsequent melt transesterification to give a polyestercarbonate.

However, it is likewise possible according to the invention for the mixture comprising the oligoester to be obtained after step (iii) by selecting the appropriate parameters, in particular the appropriate catalyst in step (ii), which directly satisfy the desired characteristics according to the invention for the OH end group content and the proportion of oligomers having a molecular weight of less than 1000 g/mol. Thus, neither step (iv) nor step (v) is required at this time.

For example, in step (i), it may be preferred that the resulting end group ratio in the mixture comprising the oligoester has been influenced by the ratio of isophthalic acid and/or terephthalic acid to the diol of formula (3). The ratio of isophthalic acid and/or terephthalic acid to the diol of formula (3) is preferably from 1.00 to 1.15, more preferably from 1.03 to 1.13, most preferably from 1.04 to 1.12. It has been found that, at ratios below 1.00, a high proportion of oligomers with a molecular weight of less than 1000g/mol is formed. As already described, these can be removed from the mixture by step (iv). However, it is therefore preferred that the ratio is higher than 1.00. Conversely, too high a ratio results in very high OH end capping. This can be reduced by step (v), also described herein. However, it is therefore preferred that the ratio is at most 1.15.

Preferably, both isophthalic acid and terephthalic acid are used in process step (i). When both diacids are used, then it is further preferred that the ratio of isophthalic acid to terephthalic acid is from 0.25 to 4.0:1, more preferably from 0.4 to 2.5:1, most preferably from 0.67 to 1.5:1. It is also preferred that the diol of formula (3) is resorcinol. Also, it is preferable and also preferable that the diaryl carbonate of formula (4) is diphenyl carbonate.

Particularly preferably, the ratio of isophthalic acid and/or terephthalic acid to diaryl carbonate of formula (4) is used in the range of 1:2 to 2.5, more preferably 1.0:2.01 to 2.25, most preferably 1.0:2.05.

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. In particular, however, terephthalic acid is insoluble under the given conditions at least initially. However, this may be varied during method step (ii). In process step (ii), carbon dioxide is generally released. This mode of operation allows for rapid reaction at low temperature loadings. Process step (ii) is preferably carried out under a protective atmosphere, preferably under nitrogen and/or argon. Step (ii) is preferably carried out in the absence of a solvent. The term "solvent" herein is known to those skilled in the art. According to the invention, the term "solvent" is preferably understood to mean a compound which does not take part in a chemical reaction in any of process steps (i), (ii) and/or (iii). This does not include those compounds formed by the reaction (e.g., phenol when diphenyl carbonate is used as the diaryl carbonate). It is of course not possible to exclude traces of solvent from the starting compounds. Preferably, this is contemplated in accordance with the present invention. However, the active step of adding such solvents is preferably avoided according to the invention.

The heating in process step (ii) is preferably carried out to a temperature of from 180℃to 300 ℃, preferably from 190℃to 270 ℃, particularly preferably from 195℃to 250 ℃. Under these temperature conditions it is possible that the corresponding aryl alcohol of the diaryl carbonate, preferably phenol, has been distilled off. The process step (ii) is preferably carried out here under standard pressure. Here, stirring is preferably carried out at standard pressure for such a long time until the gas evolution substantially ceases. Alternatively, the temperature may also be increased stepwise to 200℃to 300℃depending on the reactivity observed, preferably 210℃to 260℃and particularly preferably 215℃to 240 ℃. The reactivity can be estimated from the evolution of gas in a manner known to those skilled in the art. In principle, higher temperatures can also be used in this step, but side reactions (e.g. discoloration) can occur at higher temperatures. Higher temperatures are therefore less preferred.

It has been found that the at least one catalyst used in process step (ii) can influence the oligomer distribution of the mixture comprising the oligoester according to the invention. In process step (ii) a catalyst containing alkali metal ions, preferably sodium ions, may be used together. However, alkali metal ions remain in the mixture according to the invention. It should then be condensed by melt transesterification. However, since alkali metal ions, in particular sodium ions, can catalyze the melt transesterification, the amount of sodium left in the mixture must be accurately known and optionally determined. It is therefore advantageous not to use a catalyst comprising alkali metal ions in process step (ii).

The at least one catalyst is more preferably an organic base, preferably an alkylamine, an imidazole (derivative), a 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 advantage, inter alia, that they can be separated off by applying vacuum in process step (iii) according to the invention. This means that the resulting mixture comprising the oligoester contains only a small amount of catalyst to even no catalyst at all. This brings the advantage, in particular, that inorganic salts, which are always obtained, for example, by means of phosgene, are not present in the mixture of oligoesters and therefore also in the polyester carbonates which are later. Such salts are known to have an adverse effect on the stability of polyester carbonates, since ions can play a catalytic role in the event of corresponding degradation.

Preference is given to using mixtures of at least one organic base, for example alkylamines, imidazoles (derivatives), guanidine bases, for example triazabicyclodecene, DMAP and the corresponding derivatives, DBN or DBU, with phosphonium catalysts of the formula (VIII) (see further below). The catalyst used in process step (ii) is most preferably a mixture of 4- (dimethylamino) pyridine (DMAP) and tetrabutylphosphonium acetate.

The at least one catalyst is preferably used in an amount of 1 to 5000ppm, preferably 5 to 1000ppm, more preferably 20 to 500ppm, 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, the total amount of these catalysts is preferably from 1 to 5000ppm, preferably from 5 to 1000ppm, more preferably from 300 to 700ppm.

In process step (iii), a vacuum is applied to the mixture obtained from process step (ii). As a result, the corresponding aryl alcohol of the diaryl carbonate used, preferably phenol, is distilled off and the reaction equilibrium is shifted toward the oligoester. Aryl alcohols are compounds which are eliminated by condensation reactions.

The term "condensation" is known to those skilled in the art. Preferably, this is understood to mean a reaction in which two molecules (of the same substance or of different substances) combine to form a larger molecule, in which a molecule of a chemically simple substance is eliminated. The compounds eliminated in the condensation are removed in process step (iii) by vacuum. It is therefore preferred that the process according to the invention is characterized in that during process step (iii) volatile components having a boiling point lower than the boiling point of the oligoester mixture formed in process step (ii) are separated off, wherein the pressure is optionally reduced stepwise. When different volatile components are to be separated off, preference is given to stepwise separation. It is also preferable to choose stepwise separation to ensure as complete separation of the volatile component or components as possible. The volatile component is one or more compounds eliminated in the condensation, preferably phenol.

The pressure may be gradually reduced so that once the top temperature is reduced the pressure is reduced to ensure continuous removal of compounds eliminated in the condensation.

Preferably, the condensation product is isolated in process step (iii) at a temperature of from 200℃to 280 ℃, more preferably from 210℃to 270 ℃, particularly preferably from 220℃to 265 ℃. In addition, the vacuum during the separation is preferably from 500mbar to 0.01mbar. It is particularly preferred that the separation is stepwise by reducing the vacuum. The vacuum in the final stage is most preferably from 10mbar to 0.01mbar.

In another aspect of the invention, a polyester carbonate is provided comprising

(A) An ester group of formula (I)

Wherein R is ₁ Each independently of the others is a hydrogen atom, a halogen or an alkyl group having 1 to 4 carbon atoms, preferably hydrogen, n is at least 4, preferably 4 to 30, more preferably 5 to 27, most preferably 5 to 24, and "+" denotes the position where the ester group is incorporated in the polyestercarbonate,

(B) Carbonate groups of formula (II)

Wherein Y are each, independently of one another, a structure of the formula (III), (IV), (V) or (VI), where

Wherein the method comprises the steps of

R6 and R7 are each, independently of one another, hydrogen, C ₁ -C ₁₈ Alkyl, C ₁ -C ₁₈ Alkoxy, halogen or in each case optionally substituted aryl or aralkyl, preferably hydrogen, and

X is a single bond,-CO-、-O-、-S-、C ₁ -to C ₆ Alkylene, C ₂ -to C ₅ -alkylidene, C ₆ To C ₁₀ -cycloalkylidene, or C ₆ -to C ₁₂ Arylene which may optionally be fused to a further aromatic ring containing heteroatoms, preferably a single bond, C ₂ -to C ₅ -alkylidene or C ₆ To C ₁₀ A cycloalkylidene group, more preferably an isopropylidene group,

wherein in these formulae (IV) to (VI), R ³ Each is C ₁ -C ₄ Alkyl, aralkyl or aryl, preferably methyl or phenyl, most preferably methyl, and

", each represents the position of the carbonate group of formula (III), (IV), (V) or (VI) bonded to formula (II),

m is at least 5, preferably 8 to 300, more preferably 10 to 250, most preferably 50 to 200 and "+" each represents the position of incorporation of a carbonate group into the polyestercarbonate,

characterized in that at least some of the ester groups (A) and at least some of the carbonate groups (B) are directly linked to one another by the formula (VII), wherein

Wherein Y has the above definition of (B) and (A) represents a linkage to the ester group (A) and (B) represents a linkage to the carbonate group (B),

the polyester carbonate has a phenolic OH group content of greater than 0ppm and less than or equal to 500ppm, and

the relative solution viscosity of the polyester carbonates is at least 1.255 and up to 1.35.

The presence of the structure of formula (VII) can be determined by NMR. This is described by, for example, direct bonds of bisphenol units with isophthalic acid and/or terephthalic acid units. The bond is an ester bond. Here, the bond may be present by ¹³ C-NMR spectroscopy, wherein the chemical shift of the carbonyl carbon atom identified by the arrow in formula (VIIa) is determined.

The synthesis of model compounds formed from bisphenol A and isophthalic acid/terephthalic acid is described in the experimental section, for example, to find/calibrate the carbon in formula (VIIa) identified by the arrow ¹³ Position in C-NMR.

The polyester carbonates containing ester groups (a) and (B) prepared by the phase interface method do not have structural formula (VII) (see fig. 1). In such reactions, the OH-terminated oligoester is reacted with bisphenol (typically bisphenol a) or the corresponding oligocarbonate by reaction with phosgene to give a carbonate. This means that resorcinol units are always bonded directly to BPA units, for example, via carbonate groups.

It is obvious to the person skilled in the art that the ester groups (A) and the carbonate groups (B) may each occur multiple times in the polyester carbonates. It is also evident that n and m and the number of ester groups (A) and/or carbonate groups (B) must be selected to give the corresponding solution viscosity of the polyester carbonate. Here, the ratio of the ester group (a) in the polyester carbonate according to the present invention is preferably 5 to 90 wt%, more preferably 8 to 30 wt%, most preferably 9 to 25 wt%, relative to the total weight of the ester group (a) and the carbonate group (B). It is also preferred that the polyestercarbonates according to the invention consist of at least 80 wt.%, more preferably at least 90 wt.%, most preferably at least 95 wt.% of units of the formulae (I) and (II).

The polyester carbonates according to the invention are preferably characterized in that the relative solution viscosity of the polyester carbonates is at least 1.26 and at most 1.34. As mentioned above, this relative solution viscosity ensures good processability of the polyester carbonates, for example by injection molding. Such relative solution viscosities likewise allow good mechanical properties to be exhibited in the application areas of interest, for example in automotive exterior applications. The polyester carbonates have high stability and are inherently weather-resistant.

According to the invention, the relative solution viscosity (. Eta.rel; also known as etarel) is preferably determined using an Ubbelohde viscometer in methylene chloride at a concentration of 5g/l at 25 ℃. The determination of the relative solution viscosity by means of an Ubbelohde viscometer is known to the person skilled in the art. According to the invention, this is preferably in accordance with DIN 51562-3; 1985-05. Here, the flow time of the polyestercarbonate to be analyzed is measured by means of an unoccupied viscometer to subsequently determine the viscosity difference between the polymer solution and its solvent. For this purpose, the Ubbelohde viscometer is first calibrated by analyzing the pure solvents methylene chloride, trichloroethylene and tetrachloroethylene (at least 3 measurements, up to 9 measurements are always carried out here). The actual calibration was then performed using the solvent dichloromethane. A sample of the polymer was then weighed out, dissolved in methylene chloride, and the flow time of the solution was then determined three times. The average flow time was corrected by the Hagenbach correction and the relative solution viscosity was calculated.

It is also preferred that the polyester carbonates according to the invention have a phenolic OH group content of more than 50ppm and less than or equal to 400ppm, more preferably more than 80ppm and less than or equal to 350ppm. The phenolic OH group content is preferably determined by infrared spectroscopy. As described above with respect to the OH end groups of the mixtures according to the invention, it is also possible by ¹ H-NMR measurement. However, the signals herein may overlap. It is therefore preferred to determine the phenolic OH group content by infrared spectroscopy. For this purpose, the polyestercarbonates are preferably dissolved in methylene chloride (2 g/50 ml) and evaluated for 3583cm ^-1 Band at wavenumber. The calibration of the infrared device required for this is the presentAs known to those skilled in the art.

According to the invention, R in formula (I) is preferably ₁ Is hydrogen. Also preferably, Y in formula (II) is a structure of formula (III).

It is furthermore preferred that R6 and R7 in formula (III) are each, independently of one another, hydrogen or C ₁ -C ₁₂ Alkyl, more preferably hydrogen or C ₁ -C ₈ Alkyl, most preferably hydrogen or methyl.

It is very particularly preferred that the first and second contact surfaces, Y is selected from the group consisting of 4' -dihydroxybiphenyl, 2-bis (4-hydroxyphenyl) propane (bisphenol A), 2, 4-bis (4-hydroxyphenyl) -2-methylbutane, 1-bis (4-hydroxyphenyl) -p-diisopropylbenzene, 2-bis (3-methyl-4-hydroxyphenyl) propane, dimethyl bisphenol A, bis (3, 5-dimethyl-4-hydroxyphenyl) methane diphenols of 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, 1-bis (3, 5-dimethyl-4-hydroxyphenyl) -p-diisopropylbenzene and 1, 1-bis (4-hydroxyphenyl) -3, 5-trimethylcyclohexane, more preferably by incorporation of bisphenol A into the carbonate group (B).

The polyester carbonates according to the invention can be processed as such to give all types of molded articles. It can also be processed with other thermoplastics and/or polymer additives to give thermoplastic molding materials. Other subjects of the invention are molding compounds and molded articles. The polymer additive is preferably selected from flame retardants, drip retardants, flame retardant synergists, smoke suppressants, lubricants and mold release agents, nucleating agents, antistatic agents, conductive additives, stabilizers (e.g., hydrolysis stabilizers, heat and uv stabilizers, and transesterification inhibitors), flow promoters, compatibilizers, dyes and pigments, impact modifiers, and fillers and reinforcing agents.

Thermoplastic molding materials can be prepared, for example, by mixing the polyestercarbonates and other ingredients in a known manner and melt compounding and melt extrusion in conventional equipment, such as internal kneaders, extruders and twin-screw machines, at temperatures of preferably from 200℃to 320 ℃. In the context of the present application, this process is generally referred to as compounding. Thus, the term "molding compound" is understood to mean the product obtained when the components of the composition are melt compounded and melt extruded.

Molded articles formed from the polyester carbonates according to the invention or from thermoplastic molding compounds comprising polyester carbonates can be produced, for example, by injection molding, extrusion and blow molding processes. Another form of processing is the manufacture of molded articles by deep drawing of previously made sheets or films.

In a further aspect of the invention, a process for preparing the polyester carbonates according to the invention is provided, characterized in that the mixture according to the invention comprising oligoesters is reacted with the mixture of oligocarbonates by melt transesterification.

Melt transesterification processes are known per se to the person skilled in the art. Reference is made here, for example, to Schnell, "Chemistry and Physics of Polycarbonates", polymer Reviews, volume 9, interscience Publishers, new York, london, sydney 1964. In particular, this is a process which can be carried out in the absence of solvents and/or phosgene. For this purpose, it is necessary to melt a mixture comprising oligoesters and a mixture of oligocarbonates. Suitable temperatures for this purpose are generally from 280℃to 400℃and preferably from 300℃to 390℃and more preferably from 305℃to 350℃and even more preferably from 310℃to 340 ℃. However, it has been found according to the invention that temperatures below 320℃and preferably above 280℃to 315℃are advantageous for incorporating the oligoester blocks into the polyestercarbonates. This is especially true when using mixtures comprising oligoesters having a high OH end group content within the limits defined according to the invention.

At the same time, a vacuum is applied to shift the reaction equilibrium to the polyestercarbonate side. For this purpose, the pressure is preferably from 0.001mbar to 50mbar, more preferably from 0.005 to 40mbar, even more preferably from 0.02 to 30mbar, still more preferably from 0.03 to 5mbar.

Here, the mixture of oligocarbonates preferably has a phenolic OH group content of 250ppm to 2500ppm, preferably 500 to 2400ppm, particularly preferably 1000 to 2300ppm. The determination of the phenolic OH group content has already been described above.

It is also preferred that the mixture of oligocarbonates has a relative solution viscosity of 1.08 to 1.22, preferably 1.11 to 1.22, more preferably 1.13 to 1.20. Determination of the relative solution viscosity has also been described above.

The person skilled in the art is able to select the chemistry of the oligocarbonates, so as to produce the carbonate groups (B) of the polyester carbonates according to the invention. Particularly preferably, this is an oligocarbonate based on bisphenol A.

The process according to the invention is preferably carried out in the absence of a catalyst. Advantageously, the catalyst does not need to be separated from the resulting polyester carbonate or remain therein. Depending on the catalyst, this may affect the stability of the polyester carbonate. 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.

Catalysts which may be considered include all inorganic or organic basic compounds such as lithium, sodium, potassium, cesium, calcium, barium, magnesium hydroxides, carbonates, halides, phenolates, diphenolates, fluorides, acetates, phosphates, hydrogen phosphates, borates, nitrogen bases and phosphorus bases such as tetramethylammonium hydroxide, tetramethylammonium acetate, tetramethylammonium fluoride, tetramethylammonium tetraphenylborate, tetraphenylphosphonium fluoride, tetraphenylphosphonium tetraphenylborate, dimethyldiphenylammonium hydroxide, tetraethylammonium hydroxide, cetyltrimethylammonium tetraphenylborate, cetyltrimethylammonium phenoxide, 1, 8-diazabicyclo [5.4.0] undec-7-ene (DBU), 1, 5-diazabicyclo [4.3.0] non-5-ene (DBN), or guanidine systems, such as 1,5, 7-triazabicyclo [4.4.0] dec-5-ene, 7-phenyl-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene, 7-methyl-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene, 7' -hexamethylene di-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene, 7' -decylenedi-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene, 7' -dodecadien-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene, or phosphazenes, such as phosphazene base P1-tert-octyl = tert-octyliminotris (dimethylamino) phosphorane, phosphazene P1-tert-butyl = tert-butyliminotris (dimethylamino) phosphorane, BEMP = 2-tert-butylimino-2-diethylamino-1, 3-dimethylperfhydro-1, 3, 2-diaza-2-phosphabenzene.

Particularly suitable are phosphonium catalysts of the formula (VIII):

wherein Ra, rb, rc and Rd may be identical OR different C1-C10-alkyl, C6-C14-aryl, C7-C15-arylalkyl OR C5-C6-cycloalkyl, preferably methyl OR C6-C14-aryl, particularly preferably methyl OR phenyl, and X-may be an anion, for example hydroxide, sulfate, hydrogen carbonate, carbonate OR a halide, preferably chloride, OR an alkoxide OR aryloxide of the formula-OR, wherein R may be C6-C14-aryl, C7-C15-arylalkyl OR C5-C6-cycloalkyl, preferably phenyl.

Particularly preferred catalysts are tetraphenylphosphonium chloride, tetraphenylphosphonium hydroxide and tetraphenylphosphonium phenolate; tetraphenylphosphonium phenolate is most preferred. Tetrabutylphosphonium acetate is also preferred.

These catalysts are preferably used in an amount of 10, based on 1 mole of the oligoester mixture ^-2 To 10 ^-8 The molar amount is used. The amount of the basic salt used as the cocatalyst may be 1 to 500ppb, preferably 5 to 300ppb, particularly preferably 5 to 200ppb.

In a further aspect of the invention there is provided a polyestercarbonate obtainable by the above process according to the invention in all disclosed combinations and preferred forms.

Brief description of the drawings:

fig. 1: commercial products containing isophthalic acid/terephthalic acid-resorcinol ester blocks and BPA made by phase interface methods ¹³ C-NMR spectrum part

Examples

The materials are used:

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

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

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

Diphenyl carbonate: diphenyl carbonate, 99.5%, CAS 102-09-0; acros Organics, geel, belgium, abbreviated DPC

4-dimethylaminopyridine: 4-dimethylaminopyridine; more than or equal to 98.0 percent; analytically pure; CAS 1122-58-3; sigma-Aldrich Munchen, germany, abbreviated as DMAP

Tetrabutylphosphonium acetate: CAS-34430-94-9, prepared according to the following literature: angewandte Chemie, international edition, volume 48, phase 40, 7398-7401;2009

Sodium benzoate: 99% or more, CAS 532-32-1, sigma-Aldrich

Oligocarbonate: the starting material for the preparation of the polyestercarbonates was a linear bisphenol A oligocarbonate having phenyl end groups and phenolic OH end groups, the relative solution viscosity being 1.17. The oligocarbonate does not contain any additives such as ultraviolet stabilizers, mold release agents or heat stabilizers. The oligocarbonates were prepared by the melt transesterification process as described in WO02085967A1 and were taken off directly at the outlet of the first horizontal reactor. The phenolic end group content of the oligocarbonate was 0.16% by weight.

The analysis method comprises the following steps:

solution viscosity:

determination of solution viscosity: the relative solution viscosity (. Eta.rel; also known as eta.rel) was measured at 25℃in methylene chloride at a concentration of 5g/l using a Ubbelohde viscometer.

GPC：

Molecular weight was determined by gel permeation chromatography with methylene chloride as eluent. The standard used was BPA polycarbonate. Signals from the refractive index detector are used. The corresponding method is defined by the numbers 2301-0257502-09D of Currenta GmbH & co.ohg, which can be retrieved from Currenta at any time.

The oligomer content was likewise determined by GPC. A Refractive Index (RID) signal is used herein. The oligomer range is defined as the molecular weight distribution range <1000 g/mol. The range <1000g/mol is here evaluated as area% by integration compared to the total area of the distribution curve.

Determination of the phenolic OH end group content:

by infrared spectroscopy: the polyestercarbonates dissolved in methylene chloride (2 g/50ml;1mm quartz cuvette) were analyzed in an FT infrared spectrometer Nicolet iS10 from Thermo Fisher Scientific. Phenolic OH end group content by evaluation of wave number 3583cm ^-1 Band at (c) is determined. By passing through ¹ H-NMR spectroscopy: measurements were made in methylene chloride with tetramethylsiloxane as an internal standard. The OH group content is shown in% by weight relative to the oligomer. For evaluation, the signal of the OH group was integrated and expressed relative to the oligomer signal. Typically, the OH groups of the oligomer resonate at 5.3-5 Between 6 ppm. (however, as known to those skilled in the art, the OH signal in NMR can be shifted according to conditions such as the water content in the solvent.)

The ratio of phenyl end groups to OH end groups is determined by ¹ H-NMR spectra (Bruker, 700 MHz). Measurements were made in methylene chloride with tetramethylsiloxane as an internal standard. Here, the peak area (2 protons) at about 7.4ppm is expressed relative to the peak area (3 protons) of 6.6 to 6.8 ppm.

The bonds of isophthalic acid and/or terephthalic acid units to bisphenol A (see formula (VII)) are by ¹³ C-NMR spectroscopy.

The carbonyl carbon atom shows a shift at 164-165ppm, while the isophthalic acid and/or terephthalic resorcinol ester show a signal at about 163-164 ppm.

Measurements were made using a Bruker Avance III HD MHz NMR spectrometer. In CDCl ₃ The measurement was performed with tetramethylsilane as a standard.

Preparation of model ester compounds from BPA and terephthalic acid/isophthalic acid

21.9mmol of BPA and a total of 21.9mmol of diphenyl ester formed from terephthalic acid and isophthalic acid were initially charged in a multi-necked round bottom flask. 2.4mg of tetrabutylphosphonium acetate, which corresponds to 0.02% of the total mass, were added. The contents of the flask were deoxygenated by evacuating and inerting four times with nitrogen. The mixture was heated to 200 ℃ with continuous stirring. A condensate is continuously formed. As the amount of phenol formation increases, the initially cloudy liquid mixture becomes increasingly clear. Orange color formed, which increased in color intensity as the temperature increased to 230 ℃. About 80 minutes after the reaction was started, the pressure was reduced to 10 to 100mbar to remove phenol. The homogeneous orange-brown product was taken out.

¹³ C-NMR (600 MHz): 164.2-164.5ppm (m, 1C); IPS/TPS-BPA ester C atom (bond of isophthalic acid and/or terephthalic acid units to resorcinol)

The material is prepared to specifically recognize the signal of the ester carbon atom, which characterizes the ester formed from BPA and terephthalic acid or isophthalic acid. It can be shown that the corresponding signal is located at 164.2 to 164.5 ppm.

Preparation of oligoesters for comparative examples

Example 1

A flask with a short-path separator was initially charged with 24.93g (0.15 mol) of terephthalic acid, 24.93g (0.15 mol) of isophthalic acid, 42.94g (0.39 mol) of resorcinol, and 130.46g (0.609 mol) of diphenyl carbonate and 0.0447g of DMAP (4-dimethylaminopyridine; 200ppm, based on the starting material) and 9.9. Mu.l of an aqueous sodium benzoate solution (131.37 g/l), which corresponds to about 1ppm sodium. The mixture was deoxygenated by evacuating and charging nitrogen four times. The mixture was melted and heated to 200 ℃ under stirring at standard pressure. Since terephthalic acid is initially insoluble in the melt, a suspension is obtained. The reaction mixture was stirred at this temperature for about 3 hours. This releases carbon dioxide. Gradually heating to 240 ℃. Where phenol is distilled off. Stirred at 240℃for about 1 hour. Finally, stirring was carried out at 260℃for a further half hour. After the end of the gas evolution, the reaction mixture was cooled to 210℃and depressurized. The pressure was gradually reduced to 60mbar within 45 minutes. The temperature was raised to 230 ℃ and stirred at that temperature for half an hour. The temperature was then raised to 245 ℃. The reaction mixture was stirred for a further 0.5 hours and then the pressure was reduced to the minimum technically possible value (about 1 mbar). This gives a light brown melt. Analytical data are summarized in table 1.

Example 2

This example is carried out in principle as example 1.

Unlike example 1, a flask with a short-path separator was initially charged with 26.18g (0.1575 mol) of terephthalic acid, 26.18g (0.1575 mol) of isophthalic acid, 33.03g (0.30 mol) of resorcinol, and 141.69g (0.6615 mol) of diphenyl carbonate and 0.0441g of DMAP (4-dimethylaminopyridine; 200ppm, based on the starting material) and 9.9. Mu.l of an aqueous sodium benzoate solution (131.37 g/l), which corresponds to about 1ppm sodium.

Unlike example 1, a green oligoester was obtained.

Example 3

This example is carried out in principle as example 1.

Unlike example 1, a flask with a short-path separator was initially charged with 8.31g (0.0500 mol) of terephthalic acid, 8.31g (0.0500 mol) of isophthalic acid, 11.56g (0.105 mol) of resorcinol, and 43.91g (0.205 mol) of diphenyl carbonate and 0.0144g of DMAP (4-dimethylaminopyridine; 200ppm based on starting materials) and 3.2. Mu.l of aqueous sodium benzoate (131.37 g/l), which corresponds to about 1ppm sodium.

The mixture melted at 160 ℃ and was heated to 260 ℃ as soon as gas evolution allowed. Once no more gas was released and the suspension had been converted to solution, a holding period of 0.5 hours was carried out. The vacuum stage is carried out analogously to example 1.

Example 4

This example is carried out in principle as example 1.

Unlike example 1, a flask with a short-path separator was initially charged with 24.93g (0.1500 mol) of terephthalic acid, 24.93g (0.1500 mol) of isophthalic acid, 42.94g (0.39 mol) of resorcinol, and 130.46g (0.609 mol) of diphenyl carbonate and 0.04465g of DMAP (4-dimethylaminopyridine; 200ppm based on the starting material).

The oligoesters made with these modified preparation parameters have similar properties to the counterparts using sodium, except for the OH concentration.

Example 5

The product from example 4 was dissolved in dichloromethane and then precipitated in methanol.

Example 6

This example is carried out in principle as example 2.

Unlike example 2, a flask with a short-path separator was initially charged with 25.35g (0.1525 mol) of terephthalic acid, 25.35g (0.1525 mol) of isophthalic acid, 33.03g (0.30 mol) of resorcinol and 131.73g (0.609 mol) of diphenyl carbonate and 0.0858g of DMAP (4-dimethylaminopyridine; 400ppm based on the starting material).

The oligoesters made with these modified preparation parameters have similar properties to the counterparts using sodium.

Preparation of oligoesters useful in embodiments of the invention

Example 7

The oligoester from example 6 was dissolved in methylene chloride and then precipitated in methanol.

Example 8

This example is carried out in principle as example 1.

Unlike example 1, a flask with a short-path separator was initially charged with 20.77g (0.125 mol) of terephthalic acid, 20.77g (0.125 mol) of isophthalic acid, 28.90g (0.2625 mol) of resorcinol, and 109.79g (0.5125 mol) of diphenyl carbonate and 0.036g of DMAP (4-dimethylaminopyridine; 200ppm based on the starting material) and 0.054g of tetrabutylphosphonium acetate (300 ppm).

The experimental procedure was carried out analogously to example 1. The products had a significantly increased melt viscosity when taken out, compared with examples 2-7.

Example 9

This example is carried out in principle as example 1.

Unlike example 1, a flask with a short-path separator was initially charged with 20.77g (0.125 mol) of terephthalic acid, 20.77g (0.125 mol) of isophthalic acid, 30.28g (0.275 mol) of resorcinol and 109.79g (0.5125 mol) of diphenyl carbonate and 0.036g of DMAP (4-dimethylaminopyridine; 200ppm based on the starting material) and 0.054g of tetrabutylphosphonium acetate (300 ppm).

The experimental procedure was carried out analogously to example 1.

TABLE 1

(n.b. represents "not measured")

Examples of the synthesis of polyester carbonates from oligocarbonates and oligoester blocks from examples 1 to 9

Example 10 (comparative example)

In a flask with a short-path separator, 32.0g (80 wt%) of the oligocarbonate and 8.0g (20 wt%) of the oligocarbonate from example 1 were initially charged. The mixture was deoxygenated by evacuating and charging nitrogen four times. The mixture melted at 160℃under standard pressure. The temperature was then raised to 320 ℃. The pressure was reduced to the minimum technically possible value (about 1.5 mbar). Gradually increasing the temperature to about 335 ℃ over 30 minutes; where phenol is continuously removed. A transparent melt was obtained. Analytical data are shown in table 2.

Example 11 (comparative example)

The experiment was performed as described in example 10. Except that 36.0g of the oligocarbonate (90% by weight) and 4.0g of the oligoester from example 1 (10% by weight) were used.

Example 12

The experiment was performed as described in example 10. Except that the oligocarbonate from example 2 was used.

Example 13

The experiment was performed as described in example 10. Except that 36.0g of the oligocarbonate (90% by weight) and 4.0g of the oligoester from example 2 (10% by weight) were used.

Example 14

The experiment was performed as described in example 10. Except that the oligocarbonate from example 3 was used.

Example 15

The experiment was performed as described in example 10. Except that 36.0g of the oligocarbonate (90% by weight) and 4.0g of the oligoester from example 3 (10% by weight) were used.

Example 16

The experiment was performed as described in example 10. Except that 36.0g of the oligocarbonate (90% by weight) and 4.0g of the oligoester from example 4 (10% by weight) were used.

Example 17

The experiment was performed as described in example 10. Except that the oligocarbonate from example 4 was used.

Example 18

The experiment was performed as described in example 10. Except that 36.0g of the oligocarbonate (90% by weight) and 4.0g of the oligoester from example 5 (10% by weight) were used.

Example 19

The experiment was performed as described in example 10. Except that the oligocarbonate from example 5 was used.

Example 20

The experiment was performed as described in example 10. Except that 36.0g of the oligocarbonate (90% by weight) and 4.0g of the oligoester from example 6 (10% by weight) were used. The increase in viscosity is small compared to the previous examples.

Example 21

The experiment was performed as described in example 10. Except that the oligocarbonate from example 5 was used. The increase in viscosity is small compared to the previous examples.

Example 22

The experiment was performed as described in example 10. Except that 36.0g of the oligocarbonate (90% by weight) and 4.0g of the oligoester from example 7 (10% by weight) were used.

Example 23

The experiment was performed as described in example 10. Except that the oligocarbonate from example 7 was used.

Example 24

The experiment was performed as described in example 10. Except that 36.0g of the oligocarbonate (90% by weight) and 4.0g of the oligoester from example 8 (10% by weight) were used.

Example 25

The experiment was performed as described in example 10. Except that the oligocarbonate from example 8 was used.

Example 26

The experiment was performed as described in example 10. Except that 36.0g of the oligocarbonate (90% by weight) and 4.0g of the oligoester from example 9 (10% by weight) were used.

Example 27

The experiment was performed as described in example 10. Except that the oligocarbonate from example 9 was used.

TABLE 2

Experiment with Na catalyst

In example 1, a predominantly OH-terminated oligoester (0.6 wt% OH) was obtained. GPC of the oligoester showed only a few oligomers in the <1000g/mol range. The oligoester was used in examples 1 and 2. The respective end products show relatively high phenolic OH numbers-exceeding 500ppm in example 1. This therefore indicates that the ester blocks are less suitable, since it is not possible to obtain products below 500ppm in each case. Although example 2 has an OH number of less than 500ppm, the viscosity and thus the molecular weight are very high. Thus, in the case of correspondingly lower molecular weights, the limit value of 500ppm is likely to be exceeded.

An oligoester (0.2 wt%) with a low OH content was prepared in example 2. The blocks are predominantly phenyl-terminated. However, this block contains significant amounts of oligomers in the <1000g/mol range. Similar to example 13, in which the oligoester block from example 2 was used, the increase in molecular weight was small compared to the other examples. It is therefore shown that the reactivity is lower in the case of phenyl-terminated blocks with higher content of oligomers. Surprisingly, the desired molecular weight is not achieved despite the use of a catalyst.

An oligoester having a relatively high OH content (0.85 wt%) was prepared in example 3. The product also has a relatively high proportion of oligomers in the range <1000 g/mol. Example 15 shows that the corresponding polyester carbonates have phenolic OH numbers of >500 ppm. It is therefore not possible to prepare a complete series of polyester carbonates with different ester contents.

Example 4 shows a predominantly OH-terminated oligoester (0.80 wt% OH). Examples 16 and 17 have relatively high molecular weights (no catalyst is used), thus indicating that the OH-terminated blocks are highly reactive. However, the corresponding end products have a high content of phenolic OH end groups (> 500 ppm) both at an ester block content of 10% and at 20%.

In example 5, the ester block obtained from example 4 was precipitated. The content of phenolic OH end groups is thus reduced from 0.8% to 0.7% by weight. However, even with this block, it is not possible to prepare products with acceptable OH contents (see examples 18 and 19).

In example 6, an oligoester block with an acceptable OH content was used. However, the oligomer content in the range of <1000g/mol is relatively high. Similar to example 13, the reactivity here (examples 20 and 21) was also low, and thus the target range of molecular weight could not be reached.

In inventive examples 22 and 23, polyester carbonates with a low proportion of phenolic OH groups were prepared starting from oligoester blocks (from example 7). It has thus been shown that polyester carbonates according to the purpose can be prepared when oligoesters having a moderate OH content are used. Although the OH content of the oligoester blocks is relatively low, it is surprising that relatively high molecular weights can be achieved in the polyestercarbonates.

Surprisingly, high molecular weights (examples 24 and 25) can be achieved in polyester carbonates even at very low OH contents (oligoester blocks from example 8). Furthermore, the resulting material has a low OH content.

Inventive examples 26 and 27 likewise have a low OH content. An oligoester block having 0.2% by weight of phenolic OH groups is used here.

Claims

1. Mixtures comprising oligoesters of formula (I)

Wherein the method comprises the steps of

each q is independently of the others 0 or 1,

p represents the number of repeating units and,

2. The mixture according to claim 1, characterized in that

R ₁ In the formula (1), hydrogen is used,

up to 0.4% by weight, relative to the mixture, of the Z groups are hydrogen, and

the percentage of oligomers having a molecular weight of less than 1000g/mol is less than 10%.

3. The mixture according to any one of claims 1 or 2, characterized in that the mixture of oligoesters has a number average molecular weight of 1300g/mol to 6000 g/mol.

4. Polyester carbonates comprising

(A) An ester group of formula (I)

Wherein R is ₁ Each independently of the others is a hydrogen atom, a halogen or an alkyl group having 1 to 4 carbon atoms, n is at least 4, and "×" denotes the position at which the ester group is incorporated into the polyestercarbonate,

(B) Carbonate groups of formula (II)

Wherein the method comprises the steps of

R6 and R7 are each, independently of one another, hydrogen, C ₁ -C ₁₈ Alkyl, C ₁ -C ₁₈ Alkoxy, halogen or aryl or aralkyl optionally substituted in each case, and

x is a single bond, -CO-, -O-, -S-, C ₁ -to C ₆ Alkylene, C ₂ -to C ₅ -alkylidene, C ₆ To C ₁₀ -cycloalkylidene, or C ₆ -to C ₁₂ Arylene which may optionally be fused to a further aromatic ring containing heteroatoms,

m is at least 5, and each of "" represents the position of incorporation of a carbonate group into a polyester carbonate,

the relative solution viscosity of the polyestercarbonate is at least 1.255 and up to 1.35.

5. The polyester carbonates according to claim 4, wherein R in formula (I) ₁ Is hydrogen.

6. The polyester carbonate according to claim 4 or 5, wherein Y in formula (II) is a structure of formula (III).

7. The polyester carbonates according to any of claims 4 to 6, characterized in that R6 and R7 in formula (III) are each, independently of one another, hydrogen or C ₁ -C ₁₂ -alkyl, more preferably hydrogen or C ₁ -C ₈ -alkyl, most preferably hydrogen or methyl.

8. The polyester carbonate according to any one of claim 4 to 7, characterized in that Y is selected from the group consisting of 4' -dihydroxybiphenyl, 2-bis (4-hydroxyphenyl) propane (bisphenol A), 2, 4-bis (4-hydroxyphenyl) -2-methylbutane, 1-bis (4-hydroxyphenyl) -p-diisopropylbenzene, 2-bis (3-methyl-4-hydroxyphenyl) propane, dimethyl bisphenol A, bis (3, 5-dimethyl-4-hydroxyphenyl) methane diphenols of 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, 1-bis (3, 5-dimethyl-4-hydroxyphenyl) -p-diisopropylbenzene and 1, 1-bis (4-hydroxyphenyl) -3, 5-trimethylcyclohexane are incorporated into the carbonate group (B).

9. The polyestercarbonate according to any of claims 4 to 8, characterized in that it has a relative solution viscosity of at least 1.26 and at most 1.34.

10. The polyestercarbonate according to any of claims 4 to 9, characterized in that the polyestercarbonate has a phenolic OH group content of more than 50ppm and less than or equal to 400ppm.

11. Molding compounds comprising the polyester carbonates according to any of claims 4 to 10.

12. Molded article comprising the polyester carbonate according to any of claims 4 to 10.

13. Process for the preparation of the polyester carbonates according to any of claims 4 to 10, characterized in that the mixture comprising oligoesters according to any of claims 1 to 3 is reacted with a mixture of oligocarbonates by melt transesterification.

14. The method according to claim 14, characterized in that the mixture of oligocarbonates has a phenolic OH group content of 250ppm to 2500ppm, preferably 500 to 2400ppm, particularly preferably 1000 to 2300ppm.

15. The method according to any of claims 13 or 14, characterized in that the mixture of oligocarbonates has a relative solution viscosity of 1.08 to 1.22, preferably 1.11 to 1.22, more preferably 1.13 to 1.20.