Method for subsequent reduction of free bisphenol A content in polycarbonate and / or polyester carbonate moulding compounds

Abstract

The invention relates to a method for reducing the free BPA content in moulding compounds, comprising the following steps: a) providing a moulding compound comprising the following components: A) at least one polycarbonate and / or polyester carbonate, each containing structural units derived from bisphenol A, the moulding compound being free of vinyl polymers and olefin polymers, each functionalized with OH-reactive groups, and wherein the moulding compound contains at least one inorganic filler as component C and / or at least one basic organic colorant according to component D, or wherein the polycarbonate and / or polyester carbonate according to component A is a recycled material, the invention relates to a method for producing a moulding compound, comprising the steps of a) melting a moulding compound and sufficiently mixing the moulding compound with a polymer B selected from the group consisting of vinyl polymers and olefin polymers, each functionalized with OH-reactive groups, at a temperature of 200 DEG C to 350 DEG C, c) solidifying the melt by cooling, the content of free bisphenol A in the moulding compound being at least 20 ppm at the beginning of method step a), and moulding compounds obtainable by the method, and a molded part comprising the molding compound obtainable by the method.

Description

[0001] This invention relates to a method for reducing free bisphenol A in polycarbonate and / or polyester carbonate molding compounds, as well as molding compounds obtained by the method and molded parts containing such molding compounds.

[0002] Molding compounds containing polycarbonate and / or polyester carbonate have been used for many years in numerous applications such as automotive manufacturing, electronics, and construction. "Molding compound" refers to a polymer resin that is produced, for example, by melt compounding (melt processing) polycarbonate with a polymer blend and / or other components (such as fillers, reinforcing agents, colorants, and stabilizers). Molding compounds are typically marketed in granular form and processed into molded parts, for example, by injection molding. By selecting the types and amounts of components, the overall performance characteristics can be varied over a wide range to meet the specific application requirements. For many years, bisphenol A (BPA) has been the far most widely processed monomer unit in polycarbonate.

[0003] However, the EU is committed to reducing BPA release into the environment. This involves molding compounds (polymer granules) containing polycarbonate, as well as semi-finished products (i.e., molded parts) and finished products containing polycarbonate. As a prerequisite for future market availability, the recommended limit for chemically unbound bisphenol A (free bisphenol A) in molding compounds and semi-finished products is 10 to 150 ppm. In this invention, ppm should be understood as a weight percentage (mg / kg). In addition to reducing the free BPA content in polycarbonate, its migration scenarios could be studied alternatively, but this would require significant research expenditure.

[0004] Optimizing the composition of molding compounds with reduced free BPA content to achieve stability is a method known in the prior art.

[0005] For example, WO 2018 / 122138 A1 relates to compositions for the production of thermoplastic molding compounds, wherein the composition comprises or consists of: A) 30 to 90 wt% of at least one polymer selected from aromatic polycarbonates, aromatic polyester carbonates, and aromatic polyesters; B) 5 to 65 wt% of a rubber-modified vinyl (co)polymer prepared in bulk polymerization without epoxy groups; C) 0.5 to 10 wt% of a block or graft polymer comprising structural units derived from styrene and at least one epoxy-containing vinyl monomer; D) 0 to 20 wt% of one or more other additives, wherein the weight ratio s of the styrene-derived structural units to the epoxy-containing vinyl monomers in component C is 100:1 to 1:1. The composition has a low content of free bisphenol A.

[0006] However, during melt compounding and / or thermoforming, for example, by injection molding, the degradation of polymer chains can lead to the formation of free bisphenol A (BPA) in the molding compound and the molded part. During melt compounding, polycarbonate melts and mixes with the other components mentioned above in the melt. Studies have shown that certain components, such as inorganic fillers or inorganic pigments, particularly promote the degradation of polymer chains and the release of BPA. However, since these components are intended to impart beneficial properties to the molding compound, it is generally undesirable to avoid using them or to replace them with other components.

[0007] Molding compounds that do not contain components crucial for polymer chain degradation may also have high levels of free bisphenol A (BPA), for example, when recycled materials are involved. Recycled materials are obtained, for example, by mechanically crushing molded parts and then reprocessing the crushed material into granules by melting it. Post-consumer recycled materials fall into this category. Similarly, materials that do not immediately meet the required specifications after the production process can be remelted. Such materials are called post-industrial recycled materials. In this invention, both post-consumer recycled materials and post-industrial recycled materials are collectively referred to as recycled materials.

[0008] Throughout its life cycle, this material is subjected to thermal stress not only during melt compounding to produce the original molding compound and subsequent molding, but also during the recycling process, which is another step where thermally induced BPA release may occur.

[0009] EP 0531008 A1 discloses the production of recycled compositions in which plastic waste, made from a composition containing at least one polycarbonate, at least one polyester, and at least one impact modifier, is melted with an epoxy-functionalized copolymer derived from at least one unsaturated epoxy compound and at least one olefin. This method eliminates the need for sorting the plastic waste. However, it does not disclose the reduction of the free bisphenol A (BPA) content. As previously mentioned, BPA release is not always avoidable, thus resulting in molding compounds containing undesirable high proportions of BPA.

[0010] In order to enable these products to be sold under the anticipated regulatory restrictions, it is desirable to provide a method that can reduce the proportion of free bisphenol A already present in such polycarbonate molding compounds.

[0011] Therefore, a method should be provided that improves molding compounds with unacceptable BPA content, so as to be called a remedial method. This remedial method aims to subsequently reactively reduce free BPA in polycarbonate molding compounds to meet regulatory BPA limits.

[0012] Surprisingly, this objective was achieved by reducing the free BPA content in the molding compound, which includes the following steps: a) Provide molding compounds containing the following components A) At least one polycarbonate and / or polyester carbonate, each containing a structural unit derived from bisphenol A. The molding compound does not contain vinyl polymers and olefin polymers functionalized with OH reactive groups. b) Melt the molding compound and thoroughly mix it with polymer B, selected from vinyl polymers and olefin polymers respectively functionalized with OH reactive groups, at a temperature of 200°C to 350°C. c) Solidify the melt by cooling. At the beginning of step a), the content of free bisphenol A in the molding compound is at least 20 ppm.

[0013] The preferred method is to reduce the free BPA content in the molding compound. It includes the following steps: a) Provide molding compounds containing the following components A) At least one polycarbonate and / or polyester carbonate, each containing a structural unit derived from bisphenol A. The molding compound does not contain vinyl polymers and olefin polymers functionalized with OH reactive groups. And the molding compound It contains at least one inorganic filler as component C and / or at least one alkaline organic colorant according to component D. or Among them, the polycarbonate and / or polyester carbonate of component A are recycled materials. b) Melt the molding compound and thoroughly mix it with polymer B, selected from vinyl polymers and olefin polymers respectively functionalized with OH reactive groups, at a temperature of 200°C to 350°C. c) Solidify the melt by cooling. At the beginning of step a), the content of free bisphenol A in the molding compound is at least 20 ppm.

[0014] Therefore, for the purposes of this invention, it is not important why the free BPA content in the molding compound provided in step a) is too high, i.e., whether the cause is due to components that promote BPA release or the thermal stress experienced by the recycled material is not important.

[0015] The content of free BPA in the molding compound used in this method is preferably 20 ppm to 2000 ppm, more preferably 50 ppm to 1000 ppm, particularly preferably 100 ppm to 1000 ppm, and most preferably 200 ppm to 1000 ppm.

[0016] Component A can be a single recycled material or a mixture of different recycled materials. Furthermore, this component can also be a mixture of one or more recycled materials with one or more non-recycled materials (new materials). The respective recycled materials may originate from post-industrial or post-consumer waste.

[0017] Preferably, in step a), 0.2 to 10 parts by weight, more preferably 0.5 to 5 parts by weight of component B is used based on 100 parts by weight of molding compound.

[0018] In another preferred embodiment, the molding compound comprises at least one inorganic filler as component C and / or at least one alkaline organic colorant as component D.

[0019] The method should preferably also significantly reduce the content of free bisphenol A (BPA) within a short reaction time (i.e., a short residence time in the melt). The reduction of BPA content in the melt should be independent of the processing method employed.

[0020] It has been found that the reduction of free bisphenol A can be significantly improved by the presence of a catalyst in step a), under otherwise identical process conditions. Alternatively, the catalyst can reduce the temperature and / or residence time, both of which indicate a reduction in the thermal stress of the polymer. Therefore, the presence of a catalyst is a preferred embodiment of the invention. A molding compound is also prepared by the method according to the invention, wherein the content of free bisphenol A in the prepared molding compound is lower than that in the molding compound used.

[0021] However, after step b), the catalyst remains in the molding compound obtained by this method, which may lead to undesirable side reactions under adverse conditions when the resulting molding compound is, for example, remelted and processed into molded parts. Therefore, it is particularly desirable that the catalyst has little effect on the thermal stability of the molding compound obtained by this method.

[0022] More preferably, the presence of the catalyst should have as little effect as possible on the hydrolysis resistance (i.e., molecular weight change when stored under humid and high-temperature conditions) of the molding compound obtained in the method.

[0023] Therefore, in a particularly preferred embodiment, the catalyst is selected from nitrogen-containing catalysts. Catalysts that are not strongly acidic or basic are also preferred. This corresponds to a pKa value in the range of -5.5 to ≤9.6.

[0024] In another preferred embodiment, step a) uses 0.0005 to 0.07 parts by weight, particularly preferably 0.0015 to 0.05 parts by weight, of the catalyst based on 100 parts by weight of molding compound.

[0025] Component A The polycarbonate and / or polyester carbonate according to component A applicable to this invention are known from the literature, or can be produced by methods known in the literature (for the production of polycarbonate, see, for example, Schnell, “Chemistry and Physics of Polycarbonates”, Interscience Publishers, 1964 and DE-AS 1 495 626, DE-A 2 232 877, DE-A 2 703 376, DE-A 2 714 544, DE-A 3 000 610, DE-A 3 832 396; for the production of polyester carbonate, see, for example, DE-A 3 007 934).

[0026] According to the invention, the production of polycarbonate suitable for use as component A is, for example, by reacting bisphenol A and optionally other dihydroxyaryl compounds (also known as aromatic diols, bisphenols, or bisphenols) and / or aliphatic diols with carbonic acyl halides (preferably phosgene) and / or aromatic dicarboxylic acid dihalides (preferably phthaloyl dihalides) in an interfacial process, wherein a chain terminator (e.g., monophenol) is optionally used and a trifunctional or more than trifunctional branching agent (e.g., trihydroxyaryl or tetrahydroxyaryl compounds) is optionally used. Similarly, it can also be produced by melt polymerization by reacting bisphenol A and optionally other dihydroxyaryl compounds and / or aliphatic diols with carbonates (e.g., diphenyl carbonate).

[0027] Besides bisphenol A, the dihydroxyaryl compounds suitable for preparing polycarbonates suitable as component A according to the present invention and / or suitable for preparing polyester carbonates suitable as component A according to the present invention are preferably those of formula (2): in A is a single bond, C1- to C5-alkylene, C2- to C5-alkylidene, C5- to C6-cycloalkylidene, -O-, -SO-, -CO-, -S-, -SO2-, and can be fused to other optional aromatic rings containing heteroatoms on C6- to C6-carbon bonds. 12 - arylene, or a group of formula (3) or (4) B is C1 to C in each case. 12 -alkyl, preferably methyl, halogen, preferably chlorine and / or bromine x is 0, 1, or 2 independently of each other in each case. p is 1 or 0, and R 5 and R 6 For each X1 Individually and independently of each other, they can be hydrogen or C1 to C6-alkyl, preferably hydrogen, methyl, or ethyl. X 1 For carbon and m is an integer from 4 to 7, preferably 4 or 5, provided that at least one atom X is present. 1 Up, R 5 and R 6 It is also an alkyl group.

[0028] In addition to bisphenol A, preferred dihydroxyaryl compounds include hydroquinone, resorcinol, dihydroxybiphenyl, bis(hydroxyphenyl)alkanes, bis(hydroxyphenyl)cycloalkanes, bis(hydroxyphenyl) sulfides, bis(hydroxyphenyl) ethers, bis(hydroxyphenyl) ketones, bis(hydroxyphenyl) sulfones, bis(hydroxyphenyl) sulfoxides, α,α'-bis(hydroxyphenyl)diisopropylbenzene, benzopyrrolidones derived from indigo or phenolphthalein derivatives, and their cyclic alkylated, cyclic arylated, and cyclic halogenated compounds.

[0029] Besides bisphenol A, more preferred dihydroxyaryl compounds include 4,4'-dihydroxybiphenyl, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 1,1-bis(4-hydroxyphenyl)-p-diisopropylbenzene, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, dimethylbisphenol 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, 1,1-bis(3,5-dimethyl-4-hydroxyphenyl)-p-diisopropylbenzene, and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, as well as dihydroxyaryl compounds (I) to (III). These, along with other suitable dihydroxyaryl compounds, are listed in US 3 028 635 A, US 2 999 835 A, US 3 148 172 A, US 2 991 273 A, US 3 271 367 A, US 4 982 014 A and US 2 999 846 A, DE 1 570 703 A, DE 2063 050 A, DE 2 036 052 A, DE 2 211 956 A and DE 3 832 396 A, FR 1 561 518 A, the monograph “H. Schnell, Chemistry and Physics of Polycarbonates, Interscience Publishers, New York 1964”, and JP 62039 / 1986 A, JP 62040 / 1986 A and JP It is described in 105550 / 1986 A.

[0030] These dihydroxyaryl compounds can be used alone or in any desired mixture. These dihydroxyaryl compounds are known from the literature or can be prepared by methods known from the literature.

[0031] The polycarbonate used according to the invention preferably contains at least 20% by weight, more preferably at least 50% by weight, particularly preferably at least 80% by weight, and most preferably 100% by weight of these bisphenol A-derived structural units, in each case based on the sum of all structural units derived from dihydroxyaryl compounds.

[0032] Besides bisphenol A, suitable aliphatic diols are selected from cyclohexane-1,2-diol, cyclohexane-1,3-diol, cyclohexane-1,4-diol, cyclohexane-1,2-diethanol, cyclohexane-1,3-diethanol, cyclohexane-1,4-diethanol, 2,2-bis(4-hydroxycyclohexyl)propane, tetrahydrofuran-2,5-diethanol, 2-butyl-2-ethylpropane-1,3-diol, 2-(2-hydroxyethoxy)ethanol, and 2,2,4,4-tetramethylcyclobutane. -1,3-diol, 2,2,4-trimethylpentane-1,3-diol, 2,2-dimethylpropane-1,3-diol, cyclobutane-1,1-dimethyldiethanol, 8-(hydroxymethyl)-3-tricyclo[5.2.1.0(2,6)]decyl]methanol, propane-1,2-diol, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, octane-1,8-diol, isosorbide and any desired mixture thereof.

[0033] The polycarbonate used according to the invention preferably contains at least 20% by weight, more preferably at least 50% by weight, particularly preferably at least 80% by weight, and most preferably 100% by weight of these bisphenol A-derived structural units, in each case based on the sum of all structural units derived from dihydroxyaryl compounds and aliphatic diols.

[0034] Examples of chain terminators suitable for the preparation of polycarbonates are phenol, p-chlorophenol, p-tert-butylphenol, or 2,4,6-tribromophenol, as well as long-chain alkylphenols, such as 4-[2-(2,4,4-trimethylpentyl)]phenol, 4-(1,3-tetramethylbutyl)phenol according to DE-A 2 842 005, and monoalkylphenols or dialkylphenols having a total of 8 to 20 carbon atoms in the alkyl substituents, such as 3,5-di-tert-butylphenol, p-isooctylphenol, p-tert-octylphenol, p-dodecylphenol, 2-(3,5-dimethylheptyl)phenol, and 4-(3,5-dimethylheptyl)phenol. The amount of chain terminator used is typically from 0.5 mol% to 10 mol%, based on the total molar amount of the dihydroxyaryl compound used in each case.

[0035] The average molecular weight (weight-average molecular weight M) of thermoplastic aromatic polycarbonates w The concentration of the eluent is preferably 15,000 to 50,000 g / mol, more preferably 20,000 to 35,000 g / mol, and particularly preferably 24,000 to 32,000 g / mol. The determination is performed using GPC (gel permeation chromatography) with dichloromethane as the solvent. Calibration is performed using linear polycarbonate (made from bisphenol A and phosgene) of known molar mass distribution from PSS Polymer Standards Service GmbH, Germany, and according to Currenta GmbH & Co. OHG (Leverkusen) method 2301-0257502-09D (German version, 2009). The eluent is dichloromethane. The column assembly is made of cross-linked styrene-divinylbenzene resin. Analytical column diameter: 7.5 mm; length: 300 mm. Column material particle size: 3 µm to 20 µm. Solution concentration: 0.2 wt%. Flow rate: 1.0 ml / min; solution temperature: 30 °C. UV detection and / or refractive index detection are used. By utilizing the preferred molecular weight range of component A, a particularly advantageous balance between mechanical and rheological properties is achieved in the compositions of the present invention.

[0036] Polycarbonate can be branched in known ways, and preferably by introducing 0.05 to 2.0 mol% of a trifunctional or more trifunctional compound (e.g., a compound having three or more phenolic groups) based on the total amount of dihydroxyaryl compound used. Linear polycarbonate is preferred, and linear polycarbonate based entirely on bisphenol A is more preferred.

[0037] Both homopolymers and copolymers are applicable. To prepare the copolymer of component A according to the invention, 1 to 25% by weight, preferably 2.5 to 25% by weight, of a polydiorganosiloxane having hydroxyaryloxy terminals, based on the total amount of dihydroxyaryl compound used, may also be used. These are known (US 3 419 634) and can be prepared by methods known in the literature. For example, the preparation of copolymers containing polydiorganosiloxanes obtained in this manner is described in DE-A 3 334 782 and WO2015 / 052106 A2.

[0038] Furthermore, copolycarbonates prepared using bisphenols of general formula (4a) are preferred: (4a) in R 5 It is hydrogen or C1- to C4-alkyl, C1- to C3-alkoxy, preferably hydrogen; methoxy or methyl, R 6 R 7 R 8 and R 9 Each is independently C1- to C4-alkyl or C6- to C4-alkyl. 12 -Aryl, preferably methyl or phenyl Y is a single bond, SO2-, -S-, -CO-, -O-, C1- to C6-alkylene, C2- to C5-alkylidene, or optionally fused with other aromatic rings containing heteroatoms. 12 -arylene, or a C5- to C6-cycloalkylidene group that can be mono- or poly-substituted with C1- to C4-alkyl groups, preferably a single bond, -O-, isopropylidene, or a C5- to C6-cycloalkylidene group that can be mono- or poly-substituted with C1- to C4-alkyl groups. V is oxygen, C2- to C6-alkylene or C3- to C6-alkylidene, preferably oxygen or C3-alkylene. p, q, and r are each independently 0 or 1. When q = 0, W is a single bond; when q = 1 and r = 0, W is oxygen, C2- to C6-alkylene, or C3- to C6-alkylidene, preferably oxygen or C3-alkylene. When q = 1 and r = 1, W and V are each independently C2- to C6-alkylene or C3- to C6-alkylidene, preferably C3-alkylene. Z is a C1- to C6-alkylene, preferably a C2-alkylene. o is between 10 and 500, preferably between 10 and 100, representing the average number of repeating units. m is an average number of repeating units of 1 to 10, preferably 1 to 6, and more preferably 1.5 to 5. Similarly, bisphenols that form ester groups by interconnecting two or more siloxane blocks of general formula (4a) with each other via terephthalic acid and / or isophthalic acid can also be used.

[0039] Polysiloxanes of formulas (5) and (6) are particularly preferred. R1 is hydrogen, a C1- to C4-alkyl group, preferably hydrogen or methyl, and particularly preferably hydrogen. R2 is independently either aryl or alkyl, preferably methyl. X is a single bond, -SO2-, -CO-, -O-, -S-, C1- to C6-alkylene, C2- to C5-alkylidene, or optionally fused with other aromatic rings containing heteroatoms. 12 -Aspartic acid X is preferably a single bond, C1- to C5-alkylene group, C2- to C5-alkylidene group, or C5- to C6-alkylene group. 12 -cycloalkylidene, -O-, -SO-, -CO-, -S-, -SO2-, especially preferably X is a single bond, isopropylidene, C5- to C6-. 12 - Cycloalkylidene or oxygen, with isopropylidene being a very particular preference. n is between 10 and 400, preferably between 10 and 100, and particularly preferably an average value of 15 to 50. m is 1 to 10, preferably 1 to 6, and especially preferably an average value of 1.5 to 5.

[0040] Preferably, the siloxane block can be derived from the following structure (IV) (V), preferably (Va) (Va), or (VI) In formulas (IV), (V) and (VI), a is an average value of 10 to 400, preferably 10 to 100, and more preferably 15 to 50.

[0041] Also preferably, at least two identical or different siloxane blocks of general formula (IV), (V) or (VI) are interconnected by terephthalic acid and / or isophthalic acid to form an ester group.

[0042] Preferably, when p = 0 in formula (4a), V is a C3-alkylene group, and when r = 1, Z is a C2-alkylene group, R... 8and R 9 For methyl, when q = 1, W is a C3-alkylene group; when m = 1, R is a C3-alkylene group. 5 It is hydrogen or C1- to C4-alkyl, preferably hydrogen or methyl, R 6 and R 7 Each is independently C1- to C4-alkyl, preferably methyl, and o is 10 to 500.

[0043] WO 2015 / 052106 A2 describes copolycarbonates having monomer units of formula (4a), and in particular their preparation.

[0044] WO 2015 / 052106 A2 describes copolycarbonates having monomer units of formula (IV), and in particular their preparation.

[0045] The aromatic dicarboxylic acid diacyl halides used for preparing polyester carbonates are preferably diacyl chlorides of isophthalic acid, terephthalic acid, diphenyl ether-4,4'-dicarboxylic acid, and naphthalene-2,6-dicarboxylic acid. A mixture of isophthalic acid diacyl chloride and terephthalic acid diacyl chloride in a ratio of 1:20 to 20:1 is particularly preferred.

[0046] In the preparation of polyester carbonate, carbonic acid halides are also used, with phosgene preferred as a bifunctional acid derivative.

[0047] In addition to the aforementioned monophenols, useful chain terminators for the preparation of polyester carbonates also include their chlorocarbonates and acyl chlorides of aromatic monocarboxylic acids, which can optionally be C1- to C2-C3-C4 ... 22 -Alkyl groups or halogen atoms substituted, and aliphatic C2- to C3- 22 - Monocarboxylic acid acyl chloride. The amount of chain terminator is 0.1 to 10 mol% in each case, based on the moles of the dihydroxyaryl compound in the case of phenolic chain terminator, and based on the moles of the dicarboxylic acid diacyl chloride in the case of monocarboxylic acid acyl chloride chain terminator.

[0048] One or more aromatic hydroxycarboxylic acids may also be used in the preparation of polyester carbonates. Polyester carbonates may be linear or branched in a known manner (see DE-A 2 940 024 and DE-A 3 007 934), with linear polyester carbonates being preferred.

[0049] The branching agent used can be, for example, a trifunctional or more functional carboxylic acid acyl chloride, such as pyromellitic trichlorotrichloro, cyanurate trichloro, 3,3',4,4'-benzophenone tetracarbonyl tetrachloro, 1,4,5,8-naphthalene tetracarbonyl tetrachloro, or pyromellitic tetrachloro, in an amount of 0.01 to 1.0 mol% (based on the dicarboxylic acid dichlorotrichloro used), or a trifunctional or more functional phenol, such as phloroglucinol, 4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)hept-2-ene, 4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)heptane, 1,3,5-tris(4-hydroxyphenyl)benzene, 1,1,1- Tris(4-hydroxyphenyl)ethane, tris(4-hydroxyphenyl)phenylmethane, 2,2-bis[4,4-bis(4-hydroxyphenyl)cyclohexyl]propane, 2,4-bis(4-hydroxyphenyl isopropyl)phenol, tetra(4-hydroxyphenyl)methane, 2,6-bis(2-hydroxy-5-methylbenzyl)-4-methylphenol, 2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)propane, tetra(4-[4-hydroxyphenyl isopropyl]phenoxy)methane, 1,4-bis[4,4'-dihydroxytriphenyl)methyl]benzene, in amounts from 0.01 to 1.0 mol% (based on the dihydroxyaryl compound used). Phenolic branching agents may be pre-loaded together with the dihydroxyaryl compound; acyl chloride branching agents may be introduced together with diacyl chlorides.

[0050] The proportion of carbonate structural units in polyester carbonate can be varied as needed. The proportion of carbonate groups is preferably up to 90 mol%, particularly up to 80 mol%, more preferably up to 50 mol%, based on the sum of ester and carbonate groups. Both the ester and carbonate moieties of the polyester carbonate can exist in block form or statistically distributed within the condensation polymer.

[0051] Polycarbonate and polyester carbonate can be used alone or in any desired mixture. Preferably, bisphenol A-based polycarbonate is used as component A. "Completely bisphenol A-based" means that no other diols are used to prepare component A besides bisphenol A.

[0052] Component B In the method of the present invention, at least one polymer selected from vinyl polymers and olefin polymers, each containing an OH reactive group, is used as component B. These OH reactive groups are preferably selected from carboxyl groups, carboxylic anhydride groups, carbodiimide groups, and epoxy groups, and more preferably from carboxylic anhydride groups and epoxy groups.

[0053] The reactive group is preferably an epoxy group. This allows for a significant reduction in the content of free bisphenol A even with short component residence times and / or low temperatures in the melt.

[0054] Mixtures of different such polymers can also be used. These mixtures may each contain polymers with the same type of OH reactive groups or polymers with different OH reactive groups.

[0055] The functionalized vinyl polymers according to the present invention are preferably (co)polymers of at least one monomer selected from (meth)acrylate (C1 to C8) alkyl esters (e.g., methyl methacrylate, n-butyl acrylate, tert-butyl acrylate), vinyl aromatics (e.g., styrene, α-methylstyrene), and vinyl cyanides (unsaturated nitriles, such as acrylonitrile and methacrylonitrile) and another vinyl monomer containing an OH reactive group.

[0056] Depending on the specific performance requirements of each application, different amounts of OH reactive groups are used. The applicable molecular weight range of OH reactive products also varies. Products with a molecular weight (Mw) of 1500 to 150000 are suitable. Molecular weight refers to the data provided by the manufacturer in their product datasheet based on their analytical methods.

[0057] For example, epoxy groups are introduced by copolymerizing glycidyl methacrylate, which is one of the other monomers, with other monomers. However, vinyl homopolymers can also be used when the corresponding monomers have OH reactive groups.

[0058] Such polymers are known to be produced by free radical polymerization, particularly by emulsion polymerization, suspension polymerization, solution polymerization or bulk polymerization.

[0059] Component B is preferably a polyolefin containing OH reactive groups.

[0060] Polyolefins are produced by chain polymerization, such as by free radical polymerization. The monomers used are olefins. Another name for olefins is olefin. Monomers can be polymerized individually or as a mixture of different monomers. Preferred monomers are ethylene, propylene, 1-butene, isobutene, 1-pentene, 1-heptene, 1-octene, and 4-methyl-1-pentene.

[0061] Polyolefins can be semi-crystalline or amorphous, and can be linear or branched. The preparation of polyolefins is well known to those skilled in the art.

[0062] Polymerization can be carried out at pressures, for example, from 1 to 3000 bar and temperatures, from 20°C to 300°C, with the optional use of a catalyst system. Suitable catalysts include, for example, mixtures of titanium compounds, aluminum compounds, and metallocenes. By changing the polymerization conditions and catalyst system, the branch number, crystallinity, and density of polyolefins can be varied over a wide range. These measures are well known to those skilled in the art.

[0063] OH-reactive groups are introduced into polyolefins by copolymerizing vinyl monomers containing OH reactive groups with olefins (preferably by free radical polymerization) as described above. Suitable vinyl monomers include, for example, glycidyl methacrylate.

[0064] Another preparation possibility is to start with polyolefins and graft vinyl monomers containing OH reactive groups onto them.

[0065] In both of these preparation methods, in addition to using vinyl monomers containing OH reactive groups, other vinyl monomers without functional groups, such as styrene, can also be used.

[0066] Based on the average molecular weight (weight-average molecular weight M) of the polymer of component B. w The concentration of component B (determined by GPC (gel permeation chromatography) at room temperature using polystyrene as a standard) is preferably at least 3000 g / mol, more preferably 5000 to 200000 g / mol, and particularly preferably 6000 to 150000 g / mol. The solvent used for the GPC measurement is selected to facilitate the dissolution of component B. Suitable solvents for vinyl copolymers such as polymethyl methacrylate are, for example, tetrahydrofuran.

[0067] If the proportion of olefin monomers contained in component B makes the solubility at room temperature insufficient, high-temperature GPC is used with o-dichlorobenzene as the solvent and polystyrene as the standard for measurement.

[0068] A particularly suitable vinyl or olefin polymer based on component B is Joncryl. TM Branded glycidyl methacrylate functionalized (co)polymers (e.g., Joncryl) TM 4468 and Joncryl TM 4400), XiBond TM Branded maleic anhydride or glycidyl methacrylate functionalized (co)polymers (e.g., XiBond) TM 160, 280, 370, 920) and Lotader TM Branded maleic anhydride or glycidyl methacrylate functionalized (co)polymers (e.g., Lotader) TM AX8900), and Igetabond TM The brand's glycidyl methacrylate functionalized (co)polymers (Igetabond 2C, 7L, 7M).

[0069] Component C The molding compound used in the method of the present invention comprises, optionally, at least one inorganic filler as component C. In this invention, the term "inorganic filler" should be understood as any type of inorganic material, regardless of its chemical properties and source (e.g., natural or synthetic), particle size and particle geometry, and especially regardless of its function in the molding compound used in the method of the present invention. Therefore, "inorganic filler" according to component C is not merely understood to refer to inorganic materials used to fill polymers solely for cost reduction. Rather, the term "inorganic filler" also includes, in particular, inorganic functional fillers used as functional additives, such as reinforcing agents, pigments, flame retardants, etc.

[0070] The component C used in the molding compound of the present invention is preferably at least one inorganic filler selected from the following: silica compounds, talc, wollastonite, kaolin, CaCO3, marble powder, titanium dioxide and other inorganic pigments (inorganic colorants), Al(OH)3, AlO(OH), Mg(OH)2, BaSO4, mica, effect pigments based on metal oxide-coated mica or glass fibers, carbon black, expanded conductive graphite, glass fibers, hollow glass spheres and solid glass spheres. Preferably, the molding compound contains titanium dioxide as component C. Particularly preferred molding compounds use effect pigments based on metal oxide-coated mica as component C.

[0071] For the fillers contained in the molding compound, "preferred" means that these fillers react particularly vigorously with polycarbonate, resulting in a fairly significant formation of free bisphenol A. Therefore, the method of the present invention is particularly worthwhile for molding compounds containing such fillers.

[0072] The inorganic filler according to component C can be surface modified, wholly or partially, with one of the sizing agents containing a combination of at least one or more organic substances. These organic substances can be partially chemically bonded to the inorganic filler (e.g., when used as an adhesion promoter), while another portion can exist in a free form, i.e., physically wetting the inorganic filler in an unbonded state. The free portion of the sizing agent, i.e., the portion not chemically bonded to the inorganic filler, can be separated by extraction, for example, preferably in dichloromethane, and sent for analysis.

[0073] The glass fibers are preferably prepared from E, A, or C glass according to component C. The average diameter of the glass fibers is preferably 5 to 25 μm, more preferably 6 to 20 μm, and most preferably 7 to 15 μm. The average cut length of the chopped glass fibers is preferably 1 to 10 mm, more preferably 2.0 to 7.5 mm, and more preferably 2.5 to 5.0 mm.

[0074] It is particularly preferred to use glass fibers with an aspect ratio (i.e., the quotient of average fiber length and average fiber diameter) of at least 100, more preferably at least 200, and especially preferably at least 300.

[0075] The aforementioned geometric characteristics (length, diameter, and aspect ratio) of the glass fibers are determined on the component C used (i.e., prior to the preparation of the molding compound used in the method of the present invention, especially prior to carrying out the method of the present invention). Of course, during the preparation of molding compounds and molded parts through physical mixing processes, compounding, or thermoforming, a reduction in the aspect ratio may be unavoidable due to, for example, shearing. Therefore, the aspect ratio of the glass fibers in the molding compound used in the method of the present invention and in the molded parts produced is generally lower than the aspect ratio initially determined on the component C used.

[0076] Suitable quartz compounds are, for example, those preferably formed from more than 97% silica (quartz). Their particle shape is spherical and / or nearly spherical. The quartz compound is preferably a finely dispersed (amorphous) fused quartz powder, which is produced by iron-free milling and subsequent air classification of electrofused silica. Similarly, quartz powder made from treated quartz sand can also be used.

[0077] Commercially available fused silica powder is, for example, Amosil from Quarzwerke GmbH (Germany). TM FW200 or Amosil TM FW600. Commercially available quartz powder is, for example, Sikron from Quarzwerke GmbH (Germany). TM SF300, Sikron TM SF600, Sikron TM SF800, Silkbond TM SF600 EST, or Mikro-Dorsilit from QUARZSANDE GmbH (Austria) TM 120.

[0078] In this invention, talc is considered to be all talc-based fillers that are considered by those skilled in the art to be associated with talc or talc powder. In particular, talc is considered to be all commercially available fillers that include the term talc or talc powder as a characterizing feature in their product specifications.

[0079] A mixture of different mineral fillers based on talc can also be used.

[0080] According to the present invention, the mineral filler preferably contains more than 80% by weight, more preferably more than 95% by weight, and more preferably more than 98% by weight (based on the total mass of the filler), according to DIN 55920 (2006 edition). Talc refers to naturally occurring or synthetically produced talc. The chemical composition of pure talc is 3MgO·4SiO2·H2O, therefore its MgO content is 31.9% by weight, SiO2 content is 63.4% by weight, and chemically bound water content is 4.8% by weight. It is a silicate with a layered structure. Naturally occurring talc materials generally do not possess the above-mentioned ideal composition because they are contaminated due to the partial substitution of magnesium by other elements, the partial substitution of silicon by, for example, aluminum, and / or due to symbiosis with other minerals, such as dolomite, magnesite, and chlorite.

[0081] The talc type used as component C is preferably characterized by particularly high purity, characterized by an MgO content of 28 to 35 wt%, preferably 30 to 33 wt%, more preferably 30.5 to 32 wt%, and a SiO2 content of 55 to 65 wt%, preferably 58 to 64 wt%, more preferably 60 to 62.5 wt%. A particularly preferred talc type is further characterized by an Al2O3 content of less than 5 wt%, more preferably less than 1 wt%, and especially less than 0.7 wt%.

[0082] Advantageously and therefore preferably, the talc of the present invention is used in a finely ground form with an average particle size d. 50 The particle size is ≤10µm, preferably ≤5µm, more preferably ≤4µm, and especially preferably ≤3µm. A larger average particle size will adversely affect the mechanical properties of the molding compound of the present invention and the molded parts made therefrom.

[0083] Furthermore, it is advantageous and preferred to use the average particle size d 50 Talc with a particle size ≥0.2µm, preferably ≥0.5µm, more preferably ≥1µm, and particularly preferably ≥2µm. A smaller average particle size will adversely affect the free bisphenol A content in the molding compound of the present invention and the molded parts made therefrom.

[0084] Therefore, it is particularly advantageous to use the average particle size d. 50 The talc particle size is 0.2 to 10 µm, preferably 0.5 to 5 µm, more preferably 1 to 4 µm, and particularly preferably 2 to 3 µm. Talc with these geometric particle sizes is produced, for example and preferably, by wet milling with the addition of, for example and preferably, water. Average particle size d 50 This refers to the diameter measured by sedimentation analysis according to ISO 13317-3 (March 2001 edition), where 50% by weight of each particle is larger and smaller than this diameter. The average particle size d can also be used. 50 A mixture of different types of talc.

[0085] The talc type used according to the present invention preferably has a particle size d of less than 30 µm, more preferably less than 20 µm, more preferably less than 10 µm, and particularly preferably less than 8 µm, as determined by sedimentation analysis according to ISO 13317-3 (2001-03 edition). 95 .

[0086] The use of compacted talc is also advantageous for the processing and production of molding compounds. Compacted talc can be prepared, for example and preferably, by mixing ground talc with water and optionally other processing aids and then pressing it under high pressure. Since the processing produces molding compounds or molded parts, the talc used contributes to the molding compound or molded part's d... 97 or d 50 The value may be smaller than its original form.

[0087] Kaolin can also be used, preferably calcined kaolin as component C. The main component of naturally occurring kaolin is kaolinite, Al2(OH)4[Si2O5]; the minor components are feldspar, mica and quartz. In addition to this composition, kaolin can be used to replace kaolinite or to contain perlite, dickite, halloysite and hydrated halloysite in addition to kaolinite.

[0088] The calcined kaolin according to the present invention is obtained by heat-treating kaolin at at least 500°C, preferably 850°C to 1100°C. During this heat treatment, the hydroxyl groups that form part of the kaolin crystal structure are lost, and the kaolin is transformed into calcined kaolin.

[0089] According to the present invention, optionally organically surface-modified wollastonite can also be used as an inorganic filler. The organically surface-modified wollastonite preferably has a carbon content of greater than 0.1% by weight, preferably 0.2 to 2% by weight, more preferably 0.3 to 1% by weight, and most preferably 0.3 to 0.6% by weight, based on wollastonite content, which is determined by elemental analysis. Such wollastonite is commercially available, for example, from NYCO Minerals Inc. of Wellsboro, New York, USA, under the name Nyglos. TM Sold under the product name, model number Nyglos TM 4 or Nyglos TM 5; or, for surface-modified wollastonite, model Nyglos TM 4-10992 or Nyglos TM 5-10992.

[0090] The preferred wollastonite has an average aspect ratio (i.e., the ratio of the average length to the average diameter of the fibers) of >6, especially ≥7, and an average fiber diameter of 1 to 15 µm, preferably 2 to 10 µm, especially 4 to 8 µm.

[0091] Another suitable inorganic filler is calcium carbonate (CaCO3). Calcium carbonate exists naturally as minerals such as calcite, aragonite, and aragonite, and is a major component of limestone, chalk, and marble. Calcium carbonate can also be prepared synthetically, which may be advantageous due to the higher purity. An average particle size d is preferred. 50 It is calcium carbonate with a particle size of 0.1 to 5 µm.

[0092] Another suitable inorganic filler is Al(OH)3 hydroxide. Aluminum hydroxide naturally exists in the form of minerals such as gibbsite, diaspore, and gibbsite. Aluminum hydroxide can also be prepared synthetically, which may be advantageous due to the higher purity. An average particle size d is preferred. 50 It is calcium carbonate with a particle size of 1 to 5 µm.

[0093] Another suitable inorganic filler is mica or mica coated with metal oxides. The mica can be naturally occurring or synthetically prepared, with the latter being preferred due to its generally higher purity. Naturally obtained mica is usually accompanied by other minerals. The "mica" in naturally obtained inorganic fillers also contains corresponding impurities in the indicated amounts. The mica is preferably based on muscovite, i.e., it preferably contains at least 60% by weight, more preferably at least 70% by weight, even more preferably at least 85% by weight, and particularly preferably at least 90% by weight of muscovite, based on the total weight of the mica portion.

[0094] For mica coated with metal oxides, the metal oxide coating preferably comprises one or more coatings containing titanium dioxide, tin oxide, aluminum oxide, and / or iron oxide, wherein the metal oxide is more preferably iron(III) oxide (Fe2O3), iron(II,III) oxide (Fe3O4, i.e., a mixture of Fe2O3 and FeO) and / or titanium dioxide, with titanium dioxide being particularly preferred. Such metal oxide-coated mica is commonly used as an effects pigment.

[0095] The average particle size (d) of mica coated with optional metal oxides 50 The preferred mica size is 1 to 100 µm, more preferably 5 to 80 µm in the case of synthetic mica, more preferably 3 to 30 µm in the case of natural mica, and generally more preferably 3.5 to 15 µm in the case of mica, very particularly preferably 4.0 to 10 µm, and most preferably 4.5 to 8.0 µm, determined by laser diffraction of the aqueous suspension of the pigment. Commercially available suitable mica includes, for example, Tremica from HPF Minerals (Quarzwerke Gruppe, Germany). TM Products in the product series.

[0096] Preferably, one or more pigments (inorganic colorants) can also be used as component C or as part of component C. Pigments are understood as substances that impart color. Examples of such pigments include titanium dioxide, carbon black, bismuth pigments, metal oxides, metal hydroxides, metal sulfides, ultramarine, aquamarine, cadmium, chromium, sulfur-containing pigments (such as cadmium red and cadmium yellow), cyanide-based pigments (such as Berlin blue), oxide pigments (such as zinc oxide, iron oxide red, iron oxide black, chromium oxide, titanium yellow, zinc iron brown, titanium cobalt green, cobalt blue, copper chromium black, and copper iron black) or chromium-based pigments (such as chrome yellow) and zinc oxide. In addition, various titanates can be used, such as nickel antimony titanate and chromium antimony titanate for yellow pigments, or spinel-type aluminates for green or blue pigments. For example, these are cobalt titanium spinel or cobalt chromium spinel. These can be naturally occurring, synthetically prepared, or modified naturally occurring pigments or mixtures thereof.

[0097] The titanium dioxide pigment preferably has one of the crystal structure variants of rutile, anatase, or brookite. The preferred variant is rutile. The density of the titanium dioxide pigment according to the invention (according to DIN EN ISO 787-10) is 3.6 to 4.4 g / cm³. 3 The preferred concentration is 3.8 to 4.3 g / cm³. 3 More preferably 4.0 to 4.2 g / cm³ 3 .

[0098] Titanium dioxide pigments can be obtained from natural raw materials (such as ilmenite, rutile, or TiO2 slag) by known methods via the sulfate or chloride process. The pigments may have inorganic surface modifications, preferably based on aluminum compounds. The titanium dioxide content (according to DIN EN ISO 591) is preferably >90% by weight, more preferably >92% by weight, and even more preferably >95% by weight.

[0099] In a preferred embodiment, the oil absorption of the pigment (according to ISO 787-5) is 5 to 50 g / 100 g pigment, more preferably 10 to 25 g / 100 g pigment, and particularly preferably 12 to 18 g / 100 g pigment.

[0100] Component D The molding compound used in the method of the present invention contains, optionally, at least one basic organic colorant as component D. Such colorants (or dyes) are, for example, phthalocyanine-derived dyes, such as copper phthalocyanine blue and copper phthalocyanine green; fused polycyclic dyes and pigments, such as azo dyes (e.g., nickel azo yellow), thioindigo dyes, perylene ketone dyes, perylene dyes, quinacridone-derived dyes, dioxazinyl dyes, isoindolinone-derived dyes and quinophthalone-derived derivatives, anthraquinone-derived dyes, heterocyclic systems, etc. Preferably, cyanine dye derivatives, quinoline derivatives, anthraquinone derivatives, and phthalocyanine derivatives are used. Specific examples of commercial products are: MACROLEX Blue RR®, MACROLEX Violet 3R®, MACROLEX Violet B® (Lanxess AG, Germany), Sumiplast Violet RR, Sumiplast Violet B, Sumiplast Blue OR (Sumitomo Chemical Co., Ltd.), Diaresin Violet D, Diaresin Blue G, Diaresin Blue N (Mitsubishi Chemical Corporation), and Heliogen Blue or Heliogen Green (BASF AG, Germany).

[0101] Component E In a preferred embodiment, step a) of the method of the present invention is carried out in the presence of a catalyst. This allows the method to be carried out at a suitable temperature and / or with the molding compound and component B having a short residence time in the melt. Both of these factors help to reduce the risk of thermal damage to the molding compound.

[0102] In principle, various types of catalysts are suitable for catalyzing reactions between OH groups and OH-reactive substances. These include acidic catalysts, nucleophilic catalysts, and basic catalysts. A suitable catalyst is preferably selected from those that interact with the polycarbonate polymer chains as little as possible.

[0103] The catalyst is preferably selected from tin compounds, boron compounds, phosphorus compounds, silicon compounds, germanium compounds, transition metal compounds (e.g., titanium compounds, manganese compounds, zirconium compounds and zinc compounds), antimony compounds, nitrogen compounds, sulfur compounds, alkali metal compounds, alkaline earth metal compounds and mixtures thereof, and more preferably selected from phosphorus compounds, antimony compounds, transition metal compounds, nitrogen compounds and sulfur compounds and mixtures thereof.

[0104] In another preferred embodiment, the catalyst is free of aluminum hydroxide. In another preferred embodiment, the catalyst is based on at least one transition metal cation.

[0105] The phosphorus compound is preferably a phosphine, phosphate, or phosphonium compound, more preferably tetraphenylphosphonium. The sulfur compound is preferably a sulfonate, more preferably a trifluoromethanesulfonate compound. In a preferred embodiment, the catalyst is a nitrogen-containing compound, more preferably selected from oxadiazole, imidazoline, pyridine, and ammonium phosphate.

[0106] More preferably, this is an acidic catalyst or a nucleophilic catalyst.

[0107] Particularly preferred are catalysts containing nitrogen groups, and more preferably catalysts based on ammonium compounds. Furthermore, the catalyst preferably contains a conjugated π-electron system and nitrogen atoms.

[0108] Also preferred are catalysts that are neither too acidic nor too basic. This corresponds to a pKa value in the range of -5.5 to ≤9.6. Catalysts that are too basic can catalyze undesirable degradation reactions, such as hydrolysis or thermal oxidation. In another preferred embodiment, the method is based on organic acids having free carboxyl groups.

[0109] Component F As component F, the molding compound may contain one or more polymer additives and / or processing aids and / or other polymer components, preferably selected from flame retardants, anti-drip agents, flame retardant synergists, smoke suppressants, lubricants and release agents, nucleating agents, antistatic agents, conductive additives, stabilizers (e.g., hydrolytic stabilizers, heat aging stabilizers, UV stabilizers and transesterification inhibitors), flow promoters, phase compatibilizers, polymer blending partners different from components A and C (e.g., rubber-modified grafted polymers or rubber-free vinyl (co)polymers), and organic dyes and pigments.

[0110] In a preferred embodiment, the lubricant and release agent used are fatty acid esters, more preferably fatty acid esters of pentaerythritol or glycerol. In a preferred embodiment, the stabilizer used is at least one representative selected from sterically hindered phenols, organophosphites, and sulfur-based co-stabilizers. In a particularly preferred embodiment, the stabilizer used is at least one representative selected from octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and tris(2,4-di-tert-butylphenyl) phosphite.

[0111] In the method of the present invention, the components according to component E may also be metered and added in step a) to improve, for example, the stability of the process product, which is a molding compound.

[0112] In such a preferred embodiment, a heat stabilizer is added in step a), preferably a phosphorus-containing stabilizer, more preferably selected from organophosphites, phosphonates, or phosphates or mixtures thereof, particularly preferably selected from triisooctyl phosphate, triphenylphosphine, or organophosphites such as tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, tetrakis(2,4-di-tert-butylphenyl)(1,1'-biphenyl)-4-4'-(dimethylphosphite), and the further reaction product of phosphorus trichloride with 1,1'-biphenyl and 2,4-bis(1,1-dimethylethyl)phenol.

[0113] The stabilizer is preferably added in an amount of 0.01 to 0.3 parts by weight based on 100 parts by weight of the molding compound used in step a).

[0114] Implementing the method of the present invention Molding compound refers to the product obtained by melt compounding and melt extrusion of a composition containing component A and optionally other components C, D, and F. Another name for it is "component".

[0115] The method of the present invention uses a molding compound with a free BPA content of at least 20 ppm in step a). The method of the present invention can then be applied to various molding compounds with high free BPA content and implemented during various thermal processing of the molding compound (e.g., melt compounding in the first embodiment, and injection molding in the second embodiment). The only crucial point is that the molding compound containing at least one polycarbonate and / or polyester carbonate, each containing a structural unit derived from bisphenol A (wherein the free bisphenol A content in the molding compound is at least 20 ppm), is contacted in melt form with polymer B and thoroughly mixed.

[0116] In step a) of the method of the present invention, the molding compound is melted and thoroughly mixed with polymer B as described above at a temperature of 200°C to 350°C. This step can be performed in conventional equipment, such as a single-screw extruder, a co-rotating or counter-rotating twin-screw extruder, a planetary roll extruder, an internal kneader, or a co-kneader, or directly in a thermal processing step, such as injection molding. A twin-screw extruder or a co-kneader is preferred. Optionally, in addition to component B, a catalyst according to component E can be added in step a) to further reduce the proportion of free BPA. Similarly, other components according to component F can also be added in step a).

[0117] The temperature is preferably between 220°C and 330°C, and very particularly preferably between 260°C and 320°C. The residence time of each component in the melt is between 10 seconds and 5 minutes, preferably between 15 seconds and 3 minutes. Step a) can be carried out under vacuum or atmospheric pressure.

[0118] Step b) follows step a) by solidifying the melt through cooling. This can be done, for example, in a water bath connected to the end of the extruder through which the polymer melt passes. By means of the method of the present invention, the resulting molding compound thus has a lower free bisphenol A content than the molding compound used in step a). Similarly, at the end of the injection molding process, the resulting part can also be cooled and solidified in the injection mold.

[0119] Following step b), the molding compound can be further mixed with other components through an additional thermal processing step (e.g., a melt-blending process) to obtain a molding compound that differs from the molding compound used in step a) not only in terms of free BPA content but also in its composition. Alternatively, these other components can be metered and added in step a).

[0120] The molding compound obtained in the first embodiment of the method of the present invention (including all optional steps) is, for example, obtained in granular form. The granules can be converted into the final product (i.e., the molded part) in subsequent steps via thermal methods. This conversion can be achieved, for example, by injection molding, extrusion, and blow molding. Another processing method is to produce the molded part by deep drawing from a pre-prepared sheet or film.

[0121] However, in any case, the second scheme of the method according to the invention also achieves the reduction of free BPA even in the case of direct thermal reaction of the premixture of molding compound granules and component B and optional catalyst (e.g. in injection molding).

[0122] Examples of molded parts include (extruded) films, profiles, and various housing components, such as housing components for household appliances (e.g., juicers, coffee makers, blenders); housing components for office equipment (e.g., monitors, flat panel displays, laptops, printers, copiers); sheet metal, pipes, electrical conduits, windows, doors, and other profiles for the construction industry (interior and exterior applications); and electrical and electronic components such as switches, plugs, and sockets; components for commercial vehicles, particularly for the automotive industry; interior parts for rail vehicles, ships, aircraft, buses, and other motor vehicles; body parts for motor vehicles; housings for electrical appliances containing small transformers; housings for information processing and transmission equipment; housings and covers for medical devices; massagers and their housings; children's toy cars; sheet wall components; housings for safety devices; insulated transport containers; molded parts for sanitary and bathroom equipment; grille covers for vents; and housings for gardening tools.

[0123] Further embodiments of the present invention are listed below.

[0124] 1. Methods to reduce the free BPA content in molding compounds. It includes the following steps: a) Provide molding compounds containing the following components A) At least one polycarbonate and / or polyester carbonate, each containing a structural unit derived from bisphenol A. The molding compound does not contain vinyl polymers and olefin polymers functionalized with OH reactive groups. b) Melt the molding compound and thoroughly mix it with polymer B, selected from vinyl polymers and olefin polymers respectively functionalized with OH reactive groups, at a temperature of 200°C to 350°C. c) Solidify the melt by cooling. At the beginning of step a), the content of free bisphenol A in the molding compound is at least 20 ppm.

[0125] 2. The method according to embodiment 1, wherein the molding compound It contains at least one inorganic filler as component C and / or at least one alkaline organic colorant according to component D. or The polycarbonate and / or polyester carbonate in component A are recycled materials.

[0126] 3. The method according to implementation scheme 2, wherein the recycled material is a post-consumer recycled material.

[0127] 4. The method according to implementation scheme 2, wherein the recycled material is an industrial post-recycled material.

[0128] 5. The method according to embodiment 1, wherein component A is a polycarbonate that is entirely based on bisphenol A.

[0129] 6. The method according to any one of the foregoing embodiments, wherein in step a) 0.2-10 parts by weight, preferably 0.5 to 5 parts by weight, of component B are used based on 100 parts by weight of molding compound.

[0130] 7. The method according to any one of the foregoing embodiments, wherein the average molecular weight Mw of component B, as determined by gel permeation chromatography using polystyrene standards at room temperature, is at least 3000 g / mol.

[0131] 8. The method according to any one of the foregoing embodiments, wherein the average molecular weight Mw of component B, as determined by gel permeation chromatography using polystyrene standards at room temperature, is from 5000 g / mol to 200000 g / mol.

[0132] 9. The method according to any one of the foregoing embodiments, wherein the average molecular weight Mw of component B, as determined by gel permeation chromatography using polystyrene standards at room temperature, is from 6000 g / mol to 150000 g / mol.

[0133] 10. The method according to any one of the foregoing embodiments, wherein the polymer B used in step a) contains an OH reactive group selected from carboxylic anhydride groups and epoxy groups.

[0134] 11. The method according to any one of the foregoing embodiments, wherein the polymer B used in step a) contains an OH reactive group selected from maleic anhydride groups or glycidyl methacrylate groups.

[0135] 12. The method according to any one of the foregoing embodiments, wherein the molding compound comprises at least one inorganic filler as component C and / or at least one alkaline organic colorant according to component D.

[0136] 13. The method according to any one of the foregoing embodiments, wherein the molding compound comprises at least one inorganic filler selected from titanium dioxide, talc, silica compounds and effect pigments based on metal oxide-coated mica or glass fibers as component C.

[0137] 14. The method according to any one of the foregoing embodiments, wherein the content of free bisphenol A in the molding compound is 20 to 2000 ppm.

[0138] 15. The method according to any one of the foregoing embodiments, wherein the content of free bisphenol A in the molding compound is 50-1000 ppm.

[0139] 16. The method according to any one of the foregoing embodiments, wherein step a) is carried out in the presence of a catalyst.

[0140] 17. The method according to embodiment 16, wherein the catalyst is selected from phosphorus compounds, antimony compounds, transition metal compounds, nitrogen compounds and sulfur compounds and mixtures thereof.

[0141] 18. The method according to embodiment 16 or 17, wherein the catalyst acts as an acidic, basic or nucleophilic catalyst.

[0142] 19. The method according to any one of embodiments 16 to 18, wherein the pKa value of the catalyst is from -5.5 to ≤9.6.

[0143] 20. The method according to embodiments 16 to 19, wherein the catalyst contains nitrogen.

[0144] 21. The method according to embodiments 16 to 20, wherein the catalyst is based on an ammonium compound.

[0145] 22. The method according to embodiments 16 to 21, wherein the catalyst comprises a conjugated π-electron system and nitrogen.

[0146] 23. The method according to embodiments 16 to 19, wherein the catalyst is based on a tetraphenylphosphonium compound.

[0147] 24. The method according to embodiments 16 to 19, wherein the catalyst is based on at least one transition metal cation.

[0148] 25. The method according to embodiments 16 to 19, wherein the catalyst is based on a so-called trifluoromethanesulfonate compound.

[0149] 26. The method according to embodiments 16 to 19, wherein the catalyst is based on an organic acid having a free carboxyl group.

[0150] 27. The method according to any one of the preceding embodiments 16 to 26, wherein in step a) 0.0005 to 0.07 parts by weight of catalyst are used based on 100 parts by weight of molding compound.

[0151] 28. The method according to any one of the foregoing embodiments 16 to 26, wherein in step a), 0.0015 to 0.05 parts by weight of catalyst are used based on 100 parts by weight of molding compound.

[0152] 29. The method according to any one of the foregoing embodiments, wherein step a) is carried out in the presence of a stabilizer, preferably triisooctyl phosphate.

[0153] 30. The method according to any one of the foregoing embodiments, wherein step a) is carried out in the presence of a phosphorus-containing stabilizer, preferably selected from organophosphites, phosphonates, or phosphates or mixtures thereof.

[0154] 31. The method according to any one of the foregoing embodiments, wherein the method is carried out in process equipment selected from twin-screw extruders, planetary roll extruders, internal kneaders and film extruders.

[0155] 32. The method according to any one of the foregoing embodiments, wherein the method is carried out in process equipment selected from twin-screw extruders and co-kneaders.

[0156] 33. The method according to any one of the foregoing embodiments, wherein the dwell time in step a) is 10 seconds to 5 minutes.

[0157] 34. The method according to any one of the foregoing embodiments, wherein the dwell time in step a) is 15 seconds to 3 minutes.

[0158] 35. A molding compound obtainable by any of the foregoing embodiments.

[0159] 36. A molded part comprising a molding compound obtained by any one of embodiments 1 to 34.

[0160] 37. An extruded film comprising a molding compound obtained by any one of embodiments 1 to 34. Example

[0161] Composition of molding compound M Component A: The bisphenol A-based linear polycarbonate prepared by interfacial polymerization has a weight-average molecular weight M. w The concentration was 28000 g / mol (determined at room temperature in dichloromethane using the BPA-PC standard via GPC). The content of free bisphenol A in component A was 6 ppm, determined using the method described below.

[0162] Components C and D: In addition to component A, the molding compound also contains inorganic pigment as component C and alkaline organic colorant as component D, in a total weight ratio of 1% based on the molding compound.

[0163] Molding compound M is produced by melt blending components A, C and D at a temperature of 310°C in a ZSK 40 MC twin-screw extruder.

[0164] The free bisphenol A content in molding compound M is 418 ppm. This value is recorded in all the example tables of V1. V1 indicates that molding compound M was not subjected to further heat treatment after production.

[0165] In all other comparative experiments (V other than V1) and embodiments of the present invention, either only molding compound M was subjected to melt blending, or molding compound M was melt-blended with the following components.

[0166] Other components used in the method of the present invention Component B-1: Joncryl TM 4468 (BASF, Germany): Modified styrene-acrylate copolymer, wherein glycidyl methacrylate (GMA) comprises 44% by weight. Component B-2: Joncryl TM 4400 (BASF, Germany): Modified styrene-acrylate copolymer, wherein glycidyl methacrylate (GMA) accounts for 29% by weight. Component B-3: XiBond TM 920 (Polyscope, Netherlands): Modified styrene-acrylate copolymer, wherein glycidyl methacrylate (GMA) accounts for 20% by weight. Component B-4: XiBond TM 160 (Polyscope, Netherlands): Styrene-maleic anhydride copolymer. The proportion of maleic anhydride corresponds to an acid value of 250 (mg KOH / g). Converted to MAH content (wt%) = 21.8 Component E The catalyst of component E used in the method of the present invention Component E-1: (4-(dimethylamino)pyridine, 99% purity) (Sigma Aldrich, USA) Component E-2 (1-Phenylon, 99% purity) (Sigma Aldrich, USA) Component E-3 (2-(4-biphenyl)-5-phenyl-1,3,4-oxadiazole, 99% purity) (Sigma Aldrich, USA) Component E-4 (2-amino-5-phenyl-1,3,4-oxadiazole, 97% purity) (Sigma Aldrich, USA) Component E-5 (2-phenyl-2-imidazoline, 96% purity) (Sigma Aldrich, USA) Component E-6 (4-phenylpyridine, 99% purity) (Thermo Fisher Scientific, USA) Component E-7 (4-Dimethylaminopyridine, 98% purity) (Sigma Aldrich, USA) Component E-8 (2-phenylimidazole, 98% purity) (Sigma Aldrich, USA) Component E-9 (ammonium dihydrogen phosphate, 98% purity) (Sigma Aldrich, USA) Component E-10 (aluminum trifluoromethanesulfonate, 99.9% purity) (Sigma Alrich, USA) Component E-11 (tetraphenylphosphonium bromide, 97% purity) (Sigma Alrich, USA) Component E-12 (2-methylimidazole, 99% purity) (Sigma-Aldrich, USA) Component E-13 (glutaric acid, 99% purity) (Sigma Alrich, USA) Component E-14 (Zirconium acetylacetonate, 97% purity) (Sigma Alrich, USA) Component F Component F-1: Triisooctyl phosphate, purity ≥98.5% (Lanxess, Germany).

[0167] Implementing the method of the present invention The molding compound M and other components B, E, and F were processed by melt compounding on different equipment according to the weight ratios shown in Tables 1 to 7. The equipment used included both continuous and discontinuous process equipment. For continuous process equipment, a ZSK26 MC18 twin-screw extruder (Coperion GmbH, Stuttgart, Germany) (examples in Table 1) or a Rheomex PTWI 16 OS twin-screw extruder (Thermo Fisher Scientific Inc., Waltham, Massachusetts, USA) (examples in Table 2) was used. The examples in Tables 1 and 2 were all processed at a temperature of 300°C. For discontinuous process equipment (Tables 3-7), a small Xplore MC 15 HT extruder (Xplore Instruments BV, Sittard, Netherlands) was used. The examples in Tables 3-7 were all operated at a melt temperature of 300°C. To further evaluate the effect of different process parameters on reactive extrusion, different screw geometries were used during compounding in the twin-screw extruder (Tables 1 and 2). For this reason, the corresponding references (comparative experiments V2, V3, or V4) are always listed in their respective Tables 1-7. In all cases, components M and B were pre-dried before being used for melt processing. The residence time in the melt ranged from 20 seconds (Tables 1 and 2) to 2 minutes (Tables 3-7).

[0168] By introducing thermal and mechanical energy, the components melt and disperse, cool at the extruder outlet, and then granulate.

[0169] test To determine the content of free bisphenol A (BPA), the molding compound sample and the granules prepared according to the method of the present invention were dissolved in dichloromethane and reprecipitated with acetone. The precipitated polymer fraction was filtered off, and the filtrate was analyzed by high-performance liquid chromatography-ultraviolet detection (HPLC-UV) with an external standard. The column material used was C18 phase, and the eluents used were a gradient of water and methanol.

[0170] The results are summarized in the table below. The first column lists the proportion of free bisphenol A in each molding compound M. The second column lists the values ​​for the molding compounds used, where, in this case, the molding compounds were melt-blended under the same conditions as the experiments shown in the next column in terms of equipment, temperature, and residence time, except that components B, E, and F were not added.

[0171] Table 1: The composition used in the method of the present invention .

[0172] Example V1 is the starting pellet (molding compound M) used in the experiments related to this invention. This material has a free BPA content of 418 ppm in the pellet. Other examples and comparative examples underwent further thermal processing steps to demonstrate the effects of this invention on reducing high free BPA content. In principle, each additional processing step showed an increase in free BPA content due to thermal degradation. The more critical the formulation composition, the stronger this degradation trend, and therefore the more significant the increase in free BPA content during the thermal processing steps.

[0173] Therefore, both the examples and comparative examples used molding compounds that were critical in terms of BPA content. These contained a mixture of components C and D, which resulted in a high initial value of free BPA in the molding compound.

[0174] The data in Table 1 show that melt processing of the critical product formulation leads to an increase in free BPA content. In the method of the present invention, the use of copolymers containing OH-containing reactive groups (e.g., epoxides) according to component B significantly reduces the free bisphenol A content compared to the molding compound M (V1). This is still the case even though melt compounding implies further thermal stress, which would lead to a further increase in the proportion of free bisphenol A (V2) without the addition of component B.

[0175] Table 2: The composition used in the method of the present invention .

[0176] The data in Table 2 further demonstrate that the addition of a copolymer containing epoxy functionalized groups as OH-reactive component B results in a reduction in free BPA content, even in the presence of additional thermal stress. In Comparative Example V3, which does not contain component B, the melt blending step leads to an increase in BPA content. The addition of a suitable catalyst effectively and significantly improves this, and further reduces the free BPA content (Examples 14-17).

[0177] Table 3: The composition used in the method of the present invention .

[0178] The data in Table 3 show that, compared to the unadded approach, adding a copolymer containing epoxy functionalized groups as the OH-reactive component B, along with a suitable catalyst, significantly reduces free BPA even in discontinuous processes. It is precisely in cases of long residence times in the melt (e.g., when using discontinuous process equipment) that the use of a catalyst does not necessarily bring advantages, as the catalyst may also accelerate undesirable chemical side reactions. The use of additional stabilizers according to component F also improves the efficiency of the catalyst.

[0179] Table 4: The composition used in the method of the present invention .

[0180] Table 5: The composition used in the method of the present invention .

[0181] Table 6: The composition used in the method of the present invention .

[0182] The data in Tables 4, 5, and 6 show that different catalysts, together with component B, further reduce the proportion of free bisphenol. Different types of catalysts are suitable for catalysis. The catalysts listed in Tables (4-6) can be categorized into acidic, basic, and nucleophilic types based on their mechanisms of action. The suitability of a given catalyst cannot be limited solely to the lowest possible residual BPA content in the molding compound. Other factors influencing the suitability of the given catalyst must also be considered. Other aspects of the potential suitability of a given catalyst include: undesirable chemical catalysis (e.g., aging mechanisms of the molding compound in its respective application), catalyst availability and cost, and product safety and regulatory considerations.

[0183] Table 7: The composition used in the method of the present invention .

[0184] The data in Table 7 show the reactivity of the anhydride-functionalized copolymers according to component B to reduce the effect of free BPA.

[0185] Within a short, specific process residence time, epoxide-containing copolymers generally exhibit a more effective effect than anhydride-functionalized copolymers.

Claims

1. Methods to reduce the free BPA content in molding compounds. It includes the following steps: a) Provide molding compounds containing the following components A) At least one polycarbonate and / or polyester carbonate, each containing a structural unit derived from bisphenol A. The molding compound does not contain vinyl polymers and olefin polymers functionalized with OH reactive groups. And the molding compound It contains at least one inorganic filler as component C and / or at least one alkaline organic colorant according to component D. or Among them, the polycarbonate and / or polyester carbonate of component A are recycled materials. b) Melt the molding compound and thoroughly mix it with polymer B, selected from vinyl polymers and olefin polymers respectively functionalized with OH reactive groups, at a temperature of 200°C to 350°C. c) Solidify the melt by cooling. At the beginning of step a), the content of free bisphenol A in the molding compound is at least 20 ppm.

2. The method of claim 1, wherein component A is a polycarbonate that is entirely based on bisphenol A.

3. The method of claim 1 or 2, wherein in step a), 0.2-10 parts by weight of component B are used based on 100 parts by weight of molding compound.

4. The method of any of the preceding claims, wherein the average molecular weight Mw of component B, as determined by gel permeation chromatography using polystyrene standards at room temperature, is at least 3000 g / mol.

5. The method of any of the preceding claims, wherein the polymer B used in step a) contains an OH reactive group selected from carboxylic anhydride groups and epoxy groups.

6. The method of any of the preceding claims, wherein the molding compound comprises at least one inorganic filler as component C and / or at least one alkaline organic colorant according to component D.

7. The method as described in any of the preceding claims, wherein the content of free bisphenol A in the molding compound is 20 to 2000 ppm.

8. The method as described in any of the preceding claims, wherein step a) is carried out in the presence of a catalyst.

9. The method of claim 8, wherein the catalyst is selected from phosphorus compounds, antimony compounds, transition metal compounds, nitrogen compounds, and sulfur compounds and mixtures thereof.

10. The method as described in any one of claims 8 or 9, wherein step a) uses 0.0005 to 0.07 parts by weight of catalyst based on 100 parts by weight of molding compound.

11. The method as claimed in any of the preceding claims, wherein step a) is carried out in the presence of a stabilizer, preferably triisooctyl phosphate.

12. The method as claimed in any of the preceding claims, wherein the method is carried out in process equipment selected from twin-screw extruders, planetary roll extruders, internal kneaders and film extruders.

13. The method as claimed in any of the preceding claims, wherein the dwell time in step a) is from 10 seconds to 5 minutes.

14. A molding compound obtainable by any of the preceding claims.

15. A molded part comprising a molding compound obtained by any one of claims 1 to 13.

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