Polycarbonate compositions having a high cti

Abstract

Described are thermoplastic compositions on the basis of aromatic polycarbonate having a high comparative tracking index, good flame retardancy and a high heat deflection temperature. The compositions contain a combination of (meth)acrylate copolymer, phosphorus-containing flame retardant and fluorine-containing anti-dripping agent.

Description

[0001] Polycarbonate compositions with high CTI

[0002] The invention relates to flame-retardant thermoplastic compositions based on polycarbonate with high tracking resistance.

[0003] Polycarbonate offers many advantages over other thermoplastic polymers due to its high impact strength, high heat resistance, and a certain inherent flame retardancy. This unique property profile makes polycarbonate compositions suitable for a wide variety of applications, for example, in the field of electrical and electronic components. Good insulating properties and high flame retardancy are particularly important safety-related basic requirements for materials used in this field. In applications where the plastic is in direct contact with the electrical conductors, high resistance to leakage currents under voltage load is required to prevent short circuits and thus fire within the component.

[0004] Comparative tracking index (CTI) generally describes the resistance of a plastic material to environmental influences. The CTI value is a measure of a plastic's tendency to form electrically conductive paths on its surface when exposed to environmental influences such as moisture and contamination, and to promote resulting electrical leakage currents. The higher the tracking resistance or tracking resistance (CTI value) of a material, the better suited it is for use in high-voltage applications, e.g., in today's electromobility applications. A further advantage of materials with a high CTI value is the possibility of electrical conductors in an electronic component being located closer together without the risk of a short circuit. This in turn enables the reduction of component dimensions and thus more compact designs and weight savings.

[0005] In contrast to other thermoplastic polymers such as polystyrene, polyester, etc., polycarbonate itself has very low tracking resistance and moderate flame retardancy. Due to the high proportion of aromatic structures, polycarbonate has a relatively high tendency to carbonize. The CTI of pure polycarbonate is approximately 250 V or even lower (F. Acquasanta et al., Polymer Degradation and Stability, 96 (2011), 2098-2103). However, for numerous applications in the electrical / electrical (EE) sector, e.g., in the field of electromobility, a high CTI, typically of 600 V (corresponding to insulating material group PLC 0 according to EN 50124), is required for the materials used for safety reasons. At the same time, the materials must exhibit high flame retardancy, i.e., a VO classification according to UL 94V, especially for thin walls.Pure polycarbonate typically already possesses a certain degree of intrinsic flame retardancy (V2 classification according to UL 94 V), but this is insufficient for most applications in the renewable energy sector. To achieve the required VO classification according to UL94V, the addition of suitable flame retardants is necessary. Typically, halogenated sulfonates (e.g., Rimar salt (potassium perfluorobutanesulfonate, C4 salt) or KSS salt (potassium diphenylsulfone-3-sulfonate)) or organic phosphates (e.g., bisphenol A bis(diphenyl phosphate) (BDP), resorcinol bis(diphenyl phosphate) (RDP)) or phosphazenes are used for polycarbonate. The mechanism of action of these flame retardants is based on the formation of a solid, charred surface layer that interrupts the oxygen supply and thus inhibits the combustion process.

[0006] The underlying effect for good tracking resistance is, among other things, a low tendency to form conductive pathways on the surface. This is in direct contrast to the "charring" mechanism of action of surface-active flame retardants and thus presents a particular challenge in balancing CTI and flame retardancy.

[0007] The object was therefore to provide polycarbonate-based compositions that achieve a UL94 VO classification at 2 mm, particularly preferably at 1.5 mm, as well as a high tracking resistance of at least 400 V, preferably 600 V, preferably determined according to the rapid test method based on IEC 60112:2009. Due to the area of ​​application and the heat development in EE components, the compositions should preferably also have good heat resistance, in particular a Vicat softening temperature, determined according to ISO 306:2014-3, VST Method B, of at least 105 °C, particularly preferably at least 108 °C. In addition, the CTI should preferably be robust, i.e. the high CTI should be reliably achieved at different operating voltages, not only at 600 V, but also at 300 V or 350 V.

[0008] Surprisingly, it has been shown that this property profile can be achieved by special combinations of aromatic polycarbonate with (meth)acrylate copolymer in combination with phosphorus-containing flame retardant and with fluorine-containing anti-drip agent in certain quantities.

[0009] The invention thus relates to a thermoplastic composition containing

[0010] A) at least 68% by weight of aromatic polycarbonate,

[0011] B) 4 wt.% to 25 wt.% (meth)acrylate copolymer, wherein the (meth)acrylate copolymer comprises aromatic (meth)acrylate units b1 and methyl methacrylate units b2 in a weight ratio b1 / b2 of (5 to 20 wt.%) / (80 to 95 wt.%), based on the total weight of the (meth)acrylate copolymer,

[0012] C) 2% to 10% by weight of phosphorus-containing flame retardant,

[0013] D) 0.25 wt.% to 2 wt.% fluorine-containing anti-drip agent containing polytetrafluoroethylene, E) optionally one or more further additives selected from the group consisting of one or more mold release agents, heat stabilizers, antioxidants, dyes, pigments, UV absorbers, IR absorbers, impact modifiers, antistatic agents, optical brighteners, hydrolysis stabilizers, transesterification stabilizers, compatibilizers, additives for laser marking and mixtures thereof, wherein the wt.% details, unless otherwise stated, relate to the total composition and wherein the ratio of the amount of (meth)acrylate copolymer in wt.% and the amount of phosphorus-containing flame retardant in wt.% is < 2.5 and the ratio of the amount of (meth)acrylate copolymer in wt.% and the amount of polytetrafluoroethylene in wt.-% < 20 and wherein the thermoplastic composition is free from flame retardants selected from the group of alkali, alkaline earth and ammonium salts of aliphatic or aromatic sulfonic acid, sulfonamide and sulfonimide derivatives.

[0014] It is understood that all components contained in the composition according to the invention together amount to 100 wt.%. Where the upper limit for a numerical range is specified as "up to X," this includes the stated numerical value with its rounded upper range.

[0015] The total amount of (meth)acrylate copolymer in the composition according to the invention is 4 to 25 wt.%.

[0016] It is understood that the components used may contain common impurities, for example, resulting from their manufacturing processes. It is preferable to use components that are as pure as possible. It is further understood that these impurities may also be present in the closed formulation of the composition.

[0017] The invention also relates to molded parts produced from the thermoplastic compositions according to the invention, i.e., molded parts consisting of a thermoplastic composition according to the invention or comprising a region of a thermoplastic composition according to the invention. Such molded parts are, in particular, those for which the aforementioned property profile is particularly attractive, i.e., molded parts that are parts of components from the renewable energy sector, in particular high-voltage switches, inverters, relays, electronic connectors, electrical connectors, circuit breakers, components for photovoltaic applications, electric motors, heat sinks, chargers and plugs for electric vehicles, electrical junction boxes, smart meter housings, miniature circuit breakers, and busbars. The component is preferably designed for an operating voltage of at least 400 V.For this purpose, the material advantageously used preferably has a tracking resistance of at least 600 V, determined as described above using the rapid test method based on IEC 60112:2009.

[0018] The compositions according to the invention exhibit no significant leakage current (> 0.5 A over 2 s) upon application of at least 50 drops of a 0.1% ammonium chloride solution at 375 V, more preferably at 400 V, and especially preferably at 600 V. The test is preferably carried out according to the rapid test method described in the description section based on IEC 60112:2009. At the same time, the compositions according to the invention have a flame retardancy of V0 according to UL 94 V for test specimens with a thickness of 2 mm. In addition to the high CTI and good flame retardancy, the compositions preferably also have good heat resistance, which is demonstrated by a Vicat softening temperature, determined according to ISO 306:2014-3, VST Method B, of at least 105°C, more preferably at least 110°C ± 2°C.

[0019] It is therefore also possible to use 4 wt.% to 25 wt.%, preferably 5 wt.% to 25 wt.% (meth)acrylate copolymer, wherein the (meth)acrylate copolymer comprises aromatic (meth)acrylate units b1 and methyl methacrylate units b2 in a weight ratio b1 / b2 of (5 to 20 wt.%) / (80 to 95 wt.%), based on the total weight of the (meth)acrylate copolymer, 2 wt.% to 10 wt.% phosphorus-containing flame retardant, 0.25 wt.% to 2 wt.% fluorine-containing anti-drip agent containing polytetrafluoroethylene, wherein the wt.% data refer to the resulting total composition, to achieve a high CTI of 600 V and a UL94 VO classification with a test specimen thickness of 2 mm, in a thermoplastic composition based on aromatic polycarbonate, in particular based on bisphenol A homopoly carbonate, subject of the invention.The proportion of aromatic polycarbonate, preferably bisphenol A homopolycarbonate, in the resulting overall composition is preferably at least 68 wt.% and the ratio of the amount of (meth)acrylate copolymer in wt.% and the amount of phosphorus-containing flame retardant in wt.% is < 2.5 and the ratio of the amount of (meth)acrylate copolymer in wt.% and the amount of polytetrafluoroethylene in wt.% is < 20.

[0020] Such a targeted use also occurs, for example, when a corresponding composition is used for an insulation layer that, due to its application, requires a CTI of 600 V. Such an insulation layer can, for example, be provided on an inverter as a layer to protect against external influences. Standard insulation materials for inverters are those with a CTI of 600 V. The composition according to the invention can also be used as an insulation layer for other electrical components, e.g., transistors. The electrical components of a transistor are protected by overmolding with a plastic with a high CTI. The plastic protects the electrical components both from contact and from unwanted electrical interaction with adjacent metallic components—such as a metallic heat sink—or electrical components.Transistors are also often mounted directly onto a heat sink due to the high heat generation during operation. Here, too, the thermoplastic composition according to the invention, which is inserted between the heat sink and the transistor, ensures reliable operation.

[0021] Another field of application is mounting brackets for busbars, for which materials with a high CTI must also be used. The mounting brackets essentially have two functions: they fix the busbars within the component group to prevent them from changing their position during operation, and they act as spacers to enable multiple busbars to be run in parallel. Here too, the distance between the two bars must be sufficiently large to prevent flashover. In addition, tracking on the surface of the mounting bracket between the busbars, but also between the busbar and other metallic components, e.g. the screws used to attach the mounting bracket to the structure below, must be prevented. Mounting brackets with a high CTI can increase both the component and the energy density.

[0022] Plugs, connectors, and sockets pose a high risk of current leakage, which can lead to electrical failure and potentially fire. An enclosure that seals live wires can improve the situation, as the degree of contamination is low. Charger plugs and USB-C connectors are at increased risk because the current-carrying conductors cannot be covered or sealed and are also exposed to contaminants such as sweat, moisture, fabric particles, dust, and other materials. A material with a high CTI value is necessary to provide sufficient protection against tracking, but also to enable miniaturization and increased power density.

[0023] The features mentioned as preferred, particularly preferred, etc. for the composition naturally also apply with regard to the use according to the invention.

[0024] The individual components of the compositions according to the invention are explained in more detail below:

[0025] Component A

[0026] Component A of the compositions according to the invention are aromatic polycarbonates.

[0027] Aromatic polycarbonates within the meaning of the present invention include both homopolycarbonates and copolycarbonates and / or polyestercarbonates; the polycarbonates can be linear or branched in a known manner. Mixtures of polycarbonates can also be used according to the invention.

[0028] The thermoplastic polycarbonates, including the thermoplastic aromatic polyester carbonates, preferably have weight-average molecular weights M wfrom 15,000 g / mol to 40,000 g / mol, more preferably up to 34,000 g / mol, particularly preferably from 17,000 g / mol to 33,000 g / mol, in particular from 19,000 g / mol to 32,000 g / mol, determined by gel permeation chromatography, calibrated against bisphenol A polycarbonate standards using dichloromethane as the eluent, calibration with linear polycarbonates (from bisphenol A and phosgene) of known molar mass distribution from PSS Polymer Standards Service GmbH, Germany, calibration according to method 2301-0257502-09D (from 2009 in German) from Currenta GmbH & Co. OHG, Leverkusen. The eluent is dichloromethane. Column combination of cross-linked styrene-divinylbenzene resins. Diameter of the analytical columns: 7.5 mm; Length: 300 mm. Column material particle size: 3 pm to 20 pm. Solution concentration: 0.2 wt%. Flow rate: 1.0 ml / min. Solution temperature: 30°C. UV and / or RI detection is used.

[0029] The melt volume flow rate MVR of the aromatic polycarbonate used, determined according to ISO 1133:2012-03, at a test temperature of 300°C and a load of 1.2 kg, is preferably 5 to 35 cm 3 / (10 min), more preferably 6 cm 3 / (10 min) up to 25 cm 3 / (10 min), even more preferably 6 to 21 cm 3 / ( 10 min).

[0030] A portion, up to 80 mol%, preferably from 20 mol% to 50 mol%, of the carbonate groups in the polycarbonates used according to the invention can be replaced by aromatic dicarboxylic acid ester groups. Such polycarbonates, which contain both carbonic acid residues and acid residues of aromatic dicarboxylic acids incorporated into the molecular chain, are referred to as aromatic polyester carbonates. For the purposes of the present invention, they are subsumed under the generic term of thermoplastic aromatic polycarbonates.

[0031] Details of the production of polycarbonates have been documented in numerous patents published over the past 40 years. Examples include Schnell, "Chemistry and Physics of Polycarbonates," Polymer Reviews, Volume 9, Interscience Publishers, New York, London, Sydney 1964; D. Freitag, U. Grigo, PR Müller, H. Nouvertne, BAYER AG, "Polycarbonates" in Encyclopedia of Polymer Science and Engineering, Volume 11, Second Edition, 1988, pages 648-718; and finally, U. Grigo, K. Kirchner, and PR Müller, "Polycarbonates" in Becker / Braun, Kunststoff-Handbuch, Volume 3 / 1, Polycarbonates, Polyacetals, Polyesters, Cellulose Esters, Carl Hanser Verlag Munich, Vienna 1992, pages 117 to 299.

[0032] Aromatic polycarbonates are produced, for example, by reacting dihydroxyaryl compounds with carbonic acid halides, preferably phosgene, and / or with aromatic dicarboxylic acid dihalides, preferably benzenedicarboxylic acid dihalides, by the interfacial process, optionally using chain terminators and optionally using trifunctional or more than trifunctional branching agents. Production via a melt polymerization process is also possible by reacting dihydroxyaryl compounds with, for example, diphenyl carbonate.

[0033] For the production of polyester carbonates, part of the carbonic acid derivatives are replaced by aromatic dicarboxylic acids or derivatives of dicarboxylic acids, depending on the carbonate structural units to be replaced in the aromatic polycarbonates by aromatic dicarboxylic acid ester structural units.

[0034] Dihydroxyaryl compounds suitable for the production of polycarbonates are those of the formula (1)

[0035] HO-Z-OH (1), in which

[0036] Z is an aromatic radical having 6 to 30 C atoms, which may contain one or more aromatic nuclei, may be substituted and may contain aliphatic or cycloaliphatic radicals or alkylaryls or heteroatoms as bridge members.

[0037] Preferably, Z in formula (1) represents a radical of formula (2) in the

[0038] R 6 and R 7 independently of one another represent H, Ci- to Cis-alkyl, Ci- to Cis-alkoxy, halogen such as Cl or Br or each optionally substituted aryl or aralkyl, preferably H or Ci- to Cn-alkyl, particularly preferably H or Ci- to Cs-alkyl and very particularly preferably H or methyl, and

[0039] X represents a single bond, -SO2-, -CO-, -O-, -S-, C1- to C16-alkylene, C2- to C18-alkylidene or C5- to C16-cycloalkylidene, which may be substituted by C1- to C16-alkyl, preferably methyl or ethyl, and also C1- to C18-arylene, which may optionally be condensed with further aromatic rings containing heteroatoms. Preferably, X represents a single bond, C1- to C16-alkylene, C1- to C16-alkylidene, C1- to C16- fi -

[0040] Cycloalkylidene, -O-, -SO-, -CO-, -S-, -SO2- or a radical of the formula (3)

[0041] Examples of dihydroxyaryl compounds are: dihydroxybenzenes, dihydroxydiphenyls, bis-(hydroxyphenyl)-alkanes, bis-(hydroxyphenyl)-cycloalkanes, bis-(hydroxyphenyl)-aryls, bis-(hydroxyphenyl)-ethers, bis-(hydroxyphenyl)-ketones, bis-(hydroxyphenyl)-sulfides, bis-(hydroxyphenyl)-sulfones, bis-(hydroxyphenyl)-sulfoxides, l,l'-bis-(hydroxyphenyl)-diisopropylbenzenes and their nuclear alkylated and nuclear halogenated compounds.

[0042] Dihydroxyaryl compounds suitable for the production of polycarbonates are, for example, hydroquinone, resorcinol, dihydroxydiphenyls, bis-(hydroxyphenyl)-alkanes, bis-(hydroxyphenyl)-cycloalkanes, bis-(hydroxyphenyl)-sulfides, bis-(hydroxyphenyl)-ethers, bis-(hydroxyphenyl)-ketones, bis-(hydroxyphenyl)-sulfones, bis-(hydroxyphenyl)-sulfoxides, a-a'-bis-(hydroxyphenyl)-diisopropylbenzenes, phthalimidines derived from isatin or phenolphthalein derivatives, as well as their core-alkylated, core-arylated and core-halogenated compounds.

[0043] Preferred dihydroxyaryl compounds are 4,4'-dihydroxydiphenyl, 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A), 2,4-bis-(4-hydroxyphenyl)-2-methylbutane, 1,1-bis-(4-hydroxyphenyl)-p-diisopropylbenzene, 2,2-bis-(3-methyl-4-hydroxyphenyl)-propane, dimethyl bisphenol A, bis-(3,5-dimethyl-4-hydroxyphenyl)-methane, 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane, bis-(3,5-di-methyl-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, l-Bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, as well as dihydroxyaryl compounds (I) to (III) in which R' is in each case a C1- to C4-alkyl radical, aralkyl radical or aryl radical, preferably a methyl radical or phenyl radical, very particularly preferably a methyl radical.

[0044] Particularly preferred dihydroxyaryl compounds are 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A), 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane, l,l-bis-(4-hydroxyphenyl)-cyclohexane, l,l-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 4,4'-dihydroxydiphenyl and dimethyl-bisphenol A as well as the bisphenols of the formulas (I), (II) and (III).

[0045] These and other suitable dihydroxyaryl compounds are described, for example, 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, in DE 1 570 703 A, DE 2 063 050 A, DE 2 036 052 A, DE 2 211 956 A and DE 3 832 396 A, in FR 1 561 518 A, in the monograph "H. Schnell, Chemistry and Physics of Polycarbonates, Interscience Publishers, New York 1964" and in JP 62039 / 1986 A, JP 62040 / 1986 A and JP 105550 / 1986 A.

[0046] In the case of homopolycarbonates, only one dihydroxyaryl compound is used; in the case of copolycarbonates, two or more dihydroxyaryl compounds are used.

[0047] Suitable carbonic acid derivatives include phosgene or diphenyl carbonate.

[0048] Suitable chain terminators that can be used in the production of polycarbonates are monophenols. Examples of suitable monophenols include phenol itself, alkylphenols such as cresols, p-tert-butylphenol, cumylphenol, and mixtures thereof.

[0049] Preferred chain terminators are phenols that are mono- or polysubstituted with C1- to C30-alkyl, linear or branched, preferably unsubstituted, or substituted with tert-butyl. Particularly preferred chain terminators are phenol, cumylphenol, and / or p-tert-butylphenol.

[0050] The amount of chain terminator to be used is preferably 0.1 to 5 mol%, based on the moles of dihydroxyaryl compounds used. The chain terminators can be added before, during, or after the reaction with a carbonic acid derivative.

[0051] Suitable branching agents are the tri- or more than trifunctional compounds known in polycarbonate chemistry, in particular those with three or more than three phenolic OH groups.

[0052] Suitable branching agents are, for example, l,3,5-tri-(4-hydroxyphenyl)benzene, l,l,l-tri-(4-hydroxyphenyl)ethane, tri-(4-hydroxyphenyl)phenylmethane, 2,4-bis-(4-hydroxyphenylisopropyl)phenol, 2,6-bis-(2-hydroxy-5'-methyl-benzyl)-4-methylphenol, 2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)propane, tetra-(4-hydroxyphenyl)methane, tetra-(4-(4-hydroxyphenylisopropyl)phenoxy)methane and l,4-bis-((4',4"-dihydroxytriphenyl)methyl)benzene and 3,3-bis-(3-methyl-4-hydroxyphenyl)-2-oxo-2,3-dihydroindole. The amount of optionally used Branching agent is preferably 0.05 mol% to 2.00 mol%, based on moles of dihydroxyaryl compounds used.

[0053] The branching agents can either be added together with the dihydroxyaryl compounds and the chain terminators in the aqueous alkaline phase or dissolved in an organic solvent before phosgenation. In the case of the transesterification process, the branching agents are used together with the dihydroxyaryl compounds.

[0054] Particularly preferred polycarbonates are the homopolycarbonate based on bisphenol A, the homopolycarbonate based on l,l-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane and the copolycarbonates based on the two monomers bisphenol A and l,l-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane or the two monomers bisphenol A and 4,4'-dihydroxydiphenyl, as well as the dihydroxyaryl compounds of the formulas (I), (II) and / or (III) in which R' is each C1- to C4-alkyl, aralkyl, or aryl, preferably methyl or phenyl, most preferably methyl, derived homo- or copolycarbonates, in particular with bisphenol A. Most preferably, the aromatic polycarbonate comprises a bisphenol A-based homopolycarbonate. Most preferably, the aromatic polycarbonate is a bisphenol A-based homopolycarbonate.

[0055] The total proportion of the monomer units based on the formulas (I), (II), (III), 4,4'-dihydroxydiphenyl and / or bisphenol TMC in the copolycarbonate, if such is used, is preferably 0.1 - 88 mol%, particularly preferably 1 - 86 mol%, very particularly preferably 5 - 84 mol% and in particular 10 - 82 mol% (based on the sum of the moles of dihydroxyaryl compounds used).

[0056] The relative solution viscosity of the copolycarbonates, determined according to ISO 1628-4: 1999, is preferably in the range of 1.15 - 1.35.

[0057] The dihydroxyaryl compounds used, as well as all other chemicals and auxiliaries added to the synthesis, may be contaminated with impurities arising from their own synthesis, handling, and storage. However, it is desirable to work with raw materials that are as pure as possible.

[0058] Copolycarbonates prepared using diphenols of the general formula (4a) are also preferred: where

[0059] R 5 represents hydrogen or C1- to C4-alkyl, C1- to C5-alkoxy, preferably hydrogen; methoxy or methyl,

[0060] R 6 , R 7 , R 8 and R 9 each independently of one another represents C1- to C4-alkyl or C1- to Cn-aryl, preferably methyl or phenyl,

[0061] Y represents a single bond, SO2-, -S-, -CO-, -O-, C1- to C12-alkylene, C2- to C14-alkylidene, C15- to C12-arylene, which may optionally be condensed with further aromatic rings containing heteroatoms or a C5- to C12-cycloalkylidene radical which may be mono- or polysubstituted by C15- to C14-alkyl, preferably a single bond, -O-, isopropylidene or a C5- to C12-cycloalkylidene radical which may be mono- or polysubstituted by C15- to C14-alkyl,

[0062] V represents oxygen, C2- to C12-alkylene or C3- to C16-alkylidene, preferably oxygen or C5-alkylene, p, q and r each independently represent 0 or 1 when q = 0, W represents a single bond when q = 1 and r = 0, W represents oxygen, C2- to C12-alkylene or C3- to C16-alkylidene, preferably oxygen or C5-alkylene when q = 1 and r = 1, W and V each independently represent C2- to C12-alkylene or C5- to C16-alkylidene, preferably C5-alkylene,

[0063] Z represents a C1- to C18-alkylene, preferably C5-alkylene, o represents an average number of repeating units from 10 to 500, preferably 10 to 100, and m represents an average number of repeating units from 1 to 10, preferably 1 to 6, more preferably 1.5 to 5. It is also possible to use diphenols in which two or more siloxane blocks of the general formula (4a) are linked to one another via terephthalic acid and / or isophthalic acid to form ester groups.

[0064] Particularly preferred are (poly)siloxanes of the formulas (5) and (6) where RI is hydrogen, Ci- to C4-alkyl, preferably hydrogen or methyl and particularly preferably hydrogen,

[0065] R2 independently represent aryl or alkyl, preferably methyl,

[0066] X represents a single bond, -SO2-, -CO-, -O-, -S-, C1- to C2-alkylene, C2- to C5-alkylidene or C2- to C5-arylene, which may optionally be condensed with further aromatic rings containing heteroatoms,

[0067] X preferably represents a single bond, C1- to C5-alkylene, C2- to C5-alkylidene, C5- to C12-cycloalkylidene, -O-, -SO- -CO-, -S-, -SO2-, particularly preferably X represents a single bond, isopropylidene, C5- to Cn-cycloalkylidene or oxygen, and very particularly preferably isopropylidene, n represents an average number from 10 to 400, preferably 10 and 100, particularly preferably 15 to 50 and m represents an average number from 1 to 10, preferably from 1 to 6 and particularly preferably from 1.5 to 5.

[0068] Likewise preferably, the siloxane block can be derived from the following structure

[0069]

[0070] (VI), where a in formula (IV), (V) and (VI) represents an average number from 10 to 400, preferably 10 to 100 and particularly preferably 15 to 50.

[0071] It is also preferred that at least two identical or different siloxane blocks of the general formulas (IV), (V) or (VI) are linked to one another via terephthalic acid and / or isophthalic acid to form ester groups.

[0072] It is also preferred if in formula (4a) p = 0, V is Cs-alkylene, r = 1, Z is Cs-alkylene, R 8 and R 9 represents methyl, q = 1, W represents Cs-alkylene, m = 1, R 5 represents hydrogen or Ci- to C4-alkyl, preferably hydrogen or methyl, R 6 and R 7 each independently of one another represents Ci to C4 alkyl, preferably methyl, and o represents 10 to 500.

[0073] Copolycarbonates with monomer units of formula (4a) and in particular their preparation are described in WO 2015 / 052106 A2.

[0074] Copolycarbonates with monomer units of formula (IV) and in particular their preparation are described in WO 2015 / 052106 A2.

[0075] Aromatic dicarboxylic acids suitable for the production of polyester carbonates are, for example, orthophthalic acid, terephthalic acid, isophthalic acid, tert-butylisophthalic acid, 3,3'-diphenyldicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4-benzophenonedicarboxylic acid, 3,4'-benzophenonedicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 2,2-bis-(4-carboxyphenyl)-propane, trimethyl-3-phenylindane-4,5'-dicarboxylic acid.

[0076] Of the aromatic dicarboxylic acids, terephthalic acid and / or isophthalic acid are particularly preferred.

[0077] Derivatives of dicarboxylic acids are the dicarboxylic acid dihalides and the dicarboxylic acid dialkyl esters, in particular the dicarboxylic acid dichlorides and the dicarboxylic acid dimethyl esters.

[0078] The replacement of the carbonate groups by the aromatic dicarboxylic acid ester groups occurs essentially stoichiometrically and quantitatively, so that the molar ratio of the reactants is also reflected in the finished polyester carbonate. The incorporation of the aromatic dicarboxylic acid ester groups can occur both randomly and blockwise.

[0079] The compositions according to the invention contain at least 68% by weight, preferably at least 75% by weight, particularly preferably at least 80% by weight of aromatic polycarbonate, i.e., they are based on aromatic polycarbonate. The aromatic polycarbonate according to component A preferably comprises bisphenol A homopolycarbonate. The polycarbonate is particularly preferably bisphenol A homopolycarbonate.

[0080] Component B

[0081] Component B is a (meth)acrylate copolymer. It is understood that this can be a single (meth)acrylate copolymer or a mixture of different (meth)acrylate copolymers. Component B does not include polymers containing polyalkyl (meth)acrylate as part of a graft polymer. The polyalkyl (meth)acrylate is preferably a linear polymer.

[0082] The (meth)acrylate copolymer according to component B preferably has a weight-average molecular weight of 5000 to 30000 g / mol, more preferably 10000 to 25000 g / mol, determined by gel permeation chromatography in tetrahydrofuran under PMMA calibration.

[0083] The stated weight-average molecular weight refers to the entire (meth)acrylate copolymer contained in the composition according to the invention, i.e., if appropriate, to a mixture of different (meth)acrylate copolymers.

[0084] The (meth)acrylate copolymer comprises aromatic (meth)acrylate units (b1) and, in addition, methyl methacrylate units (b2) in a weight ratio (b1 / b2) of (5 to 80 wt.%) / (20 to 95 wt.%), most preferably in a weight ratio (b1 / b2) of (5 to 20 wt.%) / (80 to 95 wt.%), wherein the data refer to the total weight of the (meth)acrylate copolymer. According to the invention, "(Meth)acrylate" means an acrylate or a methacrylate.

[0085] Aromatic (meth)acrylate, which forms the units b1, is a (meth)acrylate that carries an aromatic group in its ester group. Such a (meth)acrylate can be used alone or in a mixture with other aromatic (meth)acrylates. Examples of aromatic (meth)acrylates are phenyl (meth)acrylate and benzyl (meth)acrylate, which are preferred aromatic (meth)acrylates according to the invention. Phenyl (meth)acrylate is particularly preferably used for units b1, particularly preferably exclusively.

[0086] The units b2 are formed by methyl methacrylate.

[0087] The proportion of component B in the compositions according to the invention is 4 wt.% to 25 wt.%, preferably 5 wt.% to 22 wt.%, more preferably 5 to 20 wt.%, even more preferably up to 15 wt.%, most preferably 5 wt.% to 10 wt.%, based on the total composition.

[0088] Component C

[0089] Component C of the compositions according to the invention comprises phosphorus-containing flame retardants. This can be a single phosphorus-containing flame retardant or a mixture of different phosphorus-containing flame retardants.

[0090] Preferred phosphorus-containing flame retardants are cyclic phosphazenes, phosphorus compounds of formula (10) and mixtures thereof:

[0091] (10), wherein

[0092] R 1 , R 2 , R 3 and R 4independently of one another represent a C 1 -C 5 -alkyl radical, in each case optionally halogenated and in each case branched or unbranched, and / or C 5 -C 12 -cycloalkyl radical, C 1 -C 20 -aryl radical or C 7 -C 12 -aralkyl radical, in each case optionally substituted by branched or unbranched alkyl and / or halogen, preferably chlorine and / or bromine, n independently of one another represent 0 or 1, q represents a value from 0 to 30 and X represents a mono- or polynuclear aromatic radical having 6 to 30 C atoms or a linear or branched aliphatic radical having 2 to 30 C atoms, which may in each case be substituted or unsubstituted, bridged or unbridged.

[0093] Preference is given to R 1 , R 2 , R 3 and R 4 independently of one another represent branched or unbranched C1- to C4-alkyl, phenyl, naphthyl or C1- to C4-alkyl-substituted phenyl. In the case of aromatic groups R 1 , R 2 , R 3 and / or R4 These, in turn, can be substituted with halogen and / or alkyl groups, preferably chlorine, bromine, and / or C1- to C4-alkyl, branched or unbranched. Particularly preferred aryl radicals are cresyl, phenyl, xylenyl, propylphenyl, or butylphenyl, as well as the corresponding brominated and chlorinated derivatives thereof.

[0094] X in formula (10) is preferably derived from dihydroxyaryl compounds.

[0095] X in formula (10) particularly preferably represents

[0096] (Xi) (Xn)

[0097] (Xiii) (XiV) or their chlorinated and / or brominated derivatives. Preferably, X (with the adjacent oxygen atoms) is derived from hydroquinone, bisphenol A or diphenylphenol. Likewise preferably, X is derived from resorcinol. More preferably, X is derived from bisphenol A. n in formula (10) is preferably 1. q preferably stands for 0 to 20, more preferably 0 to 10, and in the case of mixtures, for average values ​​of 0.8 to 5.0, preferably 1.0 to 3.0, further preferably 1.05 to 2.00 and particularly preferably 1.08 to 1.60.

[0098] As a phosphorus compound of the general formula (10), a compound of the formula (11) is preferred: wherein

[0099] R 1 , R 2 , R 3 and R 4each independently of one another represents a linear or branched C1- to C5-alkyl radical and / or optionally linear or branched alkyl-substituted C5- to C10-cycloalkyl radical, C10- to C10-aryl radical or C7- to Cn-aralkyl radical, n independently of one another represents 0 or 1, q independently of one another represents 0, 1, 2, 3 or 4,

[0100] N is a number between 1 and 30,

[0101] Rs and ; independently of one another represent a linear or branched Ci- to C4-alkyl radical, preferably methyl radical, and

[0102] Y is linear or branched C1- to C2-alkylidene radical, C5- to C1-cycloalkylene radical, C5- to C2-cycloalkylidene radical, -O-, -S-, -SO-, SO2 or -CO-.

[0103] Phosphorus compounds of formula (10) are, in particular, tributyl phosphate, triphenyl phosphate, tricresyl phosphate, diphenyl cresyl phosphate, diphenyl octyl phosphate, diphenyl 2-ethyl cresyl phosphate, tri-(isopropylphenyl) phosphate, resorcinol-bridged oligophosphate, and bisphenol A-bridged oligophosphate. The use of oligomeric phosphoric acid esters of formula (10) derived from bisphenol A is particularly preferred.

[0104] Further preference is given to using mixtures with the same structure and different chain lengths, with the stated q-value being the mean q-value. The mean q-value is determined by determining the composition of the phosphorus compound mixture (molecular weight distribution) using high-pressure liquid chromatography (HPLC) at 40°C in a mixture of acetonitrile and water (50:50), and calculating the mean q values ​​from this.

[0105] Particularly preferably, bisphenol A-based oligophosphate (bisphenol A bis(diphenyl phosphate)) according to formula (12) with q = 1 to 20, in particular with q = 1.0 to 1.2, is contained in the compositions according to the invention.

[0106] Such phosphorus compounds are known (cf. e.g. EP 0 363 608 A1, EP 0 640 655 A2) or can be prepared in an analogous manner using known methods (e.g. Ullmanns Enzyklopädie der technischen Chemie, Vol. 18, p. 301 ff., 1979; Houben-Weyl, Methoden der organischen Chemie, Vol. 12 / 1, p. 43; Beilstein Vol. 6, p. 177).

[0107] If an organophosphate is used as a phosphorus-containing flame retardant, 2 to 8 wt.% is preferably used.

[0108] Just as preferably as the phosphorus compounds according to formula (10), cyclic phosphazenes according to formula (13) can be used as component C:

[0109] (13), where

[0110] R is the same or different and for

[0111] - an amine residue,

[0112] - an optionally halogenated, preferably fluorine-halogenated, more preferably monohalogenated, Ci- to Cs-alkyl radical, preferably methyl, ethyl, propyl or butyl radical,

[0113] - a Ci to Cs alkoxy radical, preferably a methoxy radical, ethoxy radical, propoxy radical or butoxy radical,

[0114] - a C5 to C12 cycloalkyl radical optionally substituted by alkyl, preferably C1 to C4 alkyl, and / or halogen, preferably chlorine and / or bromine,

[0115] - a Ce- to C2o-aryloxy radical, preferably phenoxy radical, naphthyloxy radical, each optionally substituted by alkyl, preferably Ci- to C4-alkyl, and / or halogen, preferably chlorine, bromine, and / or hydroxy,

[0116] - a C7- to Cn-aralkyl radical, each optionally substituted by alkyl, preferably C1- to C4-alkyl, and / or halogen, preferably chlorine and / or bromine, preferably phenyl-C1- to C4-alkyl radical, or

[0117] - a halogen radical, preferably chlorine or fluorine, or

[0118] - an OH radical, k is an integer from 1 to 10, preferably a number from 1 to 8, particularly preferably

[0119] 1 to 5, most preferably 1.

[0120] According to the invention, commercially available phosphazenes are particularly preferably used. These are usually mixtures of rings of different ring sizes. Further preferred, both individually and in mixtures, are: propoxyphosphazene, phenoxyphosphazene, methylphenoxyphosphazene, aminophosphazene, fluoroalkylphosphazenes, and phosphazenes of the following structures:

[0121] (13a-f)

[0122] In the compounds 13a-f shown above, k = 1, 2 or 3.

[0123] Preferably, the proportion of phosphazenes halogen-substituted on the phosphorus, e.g. from incompletely reacted starting material, is less than 1000 ppm, more preferably less than 500 ppm.

[0124] The phosphazenes can be used alone or as a mixture. The R radical can always be the same, or two or more radicals in the formulas can be different. Preferably, the R radicals of a phosphazene are identical.

[0125] In one embodiment, only phosphazenes with the same R are used. The proportion of tetramers (k = 2) is preferably from 2 to 50 mol%, based on component B, more preferably from 5 to 40 mol%, even more preferably from 10 to 30 mol%, particularly preferably from 10 to 22 mol%.

[0126] Preferably, the proportion of the higher oligomeric phosphazenes (k = 3, 4, 5, 6 and 7) is from 0 to 30 mol%, based on component B, more preferably from 2.5 to 25 mol%, even more preferably from 5 to 20 mol%, and particularly preferably from 6 to 15 mol%.

[0127] Preferably, the proportion of oligomers with k > 8 is from 0 to 2.0 mol%, based on component B, and preferably from 0.10 to 1.00 mol%.

[0128] More preferably, the phosphazenes of component C fulfill all three of the above-mentioned conditions with regard to the proportions of oligomers.

[0129] Particularly preferably, phenoxyphosphazene (all R = phenoxy, formula 13g), alone or with further phosphazenes according to formula (13) is contained as component C, with a proportion of oligomers with k = 1 (hexaphenoxyphosphazene) of 50 to 98 mol%, particularly preferably 60 to 72 wt.%, based on the amount of phenoxyphosphazene, as component C. If phenoxyphosphazene is used, the proportion of oligomers with k = 2 is very particularly preferably 15 to 22 wt.% and with k > 3: 10 to 13 wt.%.

[0130] Alternatively, very particularly preferably, component C comprises a phenoxyphosphazene having a trimer content (k = 1) of 70 to 85 mol%, a tetramer content (k = 2) of 10 to 20 mol%, a content of higher oligomeric phosphazenes (k = 3, 4, 5, 6 and 7) of 3 to 8 mol% and phosphazene oligomers with k > 8 of 0.1 to 1 mol%, based on component C.

[0131] In an alternative preferred embodiment, n, defined as the arithmetic mean of k, is in the range from 1.10 to 1.75, preferably from 1.15 to 1.50, more preferably from 1.20 to 1.45, and most preferably from 1.20 to 1.40 (range limits included).

[0132] The phosphazenes and their preparation are described, for example, in EP 728 811 A2, DE 1961668 A and WO 97 / 40092 A1.

[0133] The oligomer compositions in the respective blend samples can be determined after compounding using 31 Detect and quantify by P-NMR (chemical shift; 5 trimer: 6.5 to 10.0 ppm; 5 tetramer: -10 to -13.5 ppm; 5 higher oligomers: -16.5 to -25.0 ppm).

[0134] If the phosphorus-containing flame retardant is a phosphazene, preferably 2 wt.% to 8 wt.%, more preferably 4 to 8 wt.%, are used.

[0135] Very particularly preferably, component C comprises bisphenol-A-based oligophosphate according to formula (12) and / or cyclic phosphazene according to formula (13), most preferably component C is bisphenol-A-based oligophosphate according to formula (12) and / or cyclic phosphazene according to formula (13).

[0136] The proportion of phosphorus-containing flame retardant in the compositions according to the invention is from 2 wt.% to 10 wt.%, preferably from 2 wt.% to 8 wt.%, particularly preferably up to 6 wt.%, very particularly preferably up to <5 wt.%, extremely preferably up to 4 wt.%, based on the total composition. As the proportion of the phosphorus-containing flame retardant increases, the Vicat temperature decreases significantly.

[0137] Component D

[0138] The compositions according to the invention contain, as component D, a fluorine-containing anti-drip agent containing polytetrafluoroethylene, which may be a mixture of several anti-drip agents. The total amount of anti-drip agent is 0.25 wt.% to 2 wt.%, preferably 0.4 wt.% to 1 wt.%, particularly preferably 0.5 wt.% to 1.0 wt.% of at least one anti-drip agent.

[0139] The fluorinated polyolefins preferably used as anti-drip agents are high molecular weight and have glass transition temperatures above -30°C, generally above 100°C, and fluorine contents preferably of 65% to 76% by weight, especially of 70% to 76% by weight. Preferred fluorinated polyolefins are polytetrafluoroethylene, which is always present, polyvinylidene fluoride, tetrafluoroethylene / hexafluoropropylene, and ethylene / tetrafluoroethylene copolymers. Fluorinated polyolefins are known (cf. “Vinyl and Related Polymers” by Schildknecht, John Wiley & Sons, Inc., New York, 1962, pages 484-494; “Fluoropolymers” by Wall, Wiley-Interscience, John Wiley & Sons, Inc., New York, Volume 13, 1970, pages 623-654; “Modem Plastics Encyclopedia”, 1970-1971, Volume 47, No. 10 A, October 1970, Mc Graw-Hill, Inc., New York, pages 134 and 774; “Modem Plastics Encyclopedia”, 1975-1976, October 1975, Volume 52, No. 10 A, Mc Graw-Hill, Inc., New York, pages 27, 28 and 472 and US 3,671,487 A, 3,723,373 A and 3,838,092 A). They can be prepared by known processes, for example by polymerising tetrafluoroethylene in an aqueous medium with a free radical-forming catalyst, for example sodium, potassium or ammonium peroxodisulphate, at pressures of 7 to 71 kg / cm. 2 and at temperatures from 0 to 200°C, preferably at temperatures from 20 to 100°C. Further details are described, for example, in US Pat. No. 2,393,967.

[0140] Depending on the application, the density of the fluorinated polyolefins can be between 1.2 and 2.3 g / cm 3 , preferably 2.0 g / cm 3 up to 2.3 g / cm 3 ' determined according to ISO 1183-1 (2019-09), the mean particle size is between 0.05 and 1000 pm, determined by light microscopy or white light interferometry.

[0141] Suitable tetrafluoroethylene polymer powders are commercially available products and are offered, for example, by DuPont under the trade name Teflon®.

[0142] Polytetrafluoroethylene (PTFE) as such, but also in the form of a PTFE-containing composition, is particularly preferably used as the fluorine-containing anti-drip agent. If a PTFE-containing composition is used, its minimum use amount is preferably such that at least 0.15 wt.%, particularly preferably at least 0.25 wt.% PTFE is contained in the total composition. PTFE-containing compositions include Hostaflon® TF2021 or PTFE blends such as Blendex® B449 (approx. 50 wt.% PTFE and approx. 50 wt.% SAN [consisting of 80 wt.% styrene and 20 wt.% acrylonitrile]) from Chemtura. PTFE or a PTFE / SAN blend is very particularly preferably used as the fluorine-containing anti-drip agent; the fluorine-containing anti-drip agent is most preferably PTFE or PTFE / SAN.

[0143] Component E

[0144] The polycarbonate compositions according to the invention may contain one or more further additives other than components B, C and D, which are summarized here under “component E”.

[0145] Optionally (0 wt. %) to preferably 12 wt. %, more preferably up to 5 wt. %, even more preferably up to 3 wt. %, in particular 0.1 wt. % to 3 wt. %, particularly preferably 0.2 wt. % to 1 wt. %, most preferably 0.5 wt. % to 1.0 wt. % of other customary additives (“further additives”) are present, wherein these percentages by weight are based on the total weight of the composition. The group of further additives does not comprise a phosphorus-containing flame retardant according to component C. The group of further additives also comprises, in particular, no fluorine-containing anti-drip agent, since this has already been described as component D.Such further additives, as are typically added to polycarbonates, include heat stabilizers, antioxidants, mold release agents, UV absorbers, IR absorbers, impact modifiers, antistatic agents, optical brighteners, light scattering agents, hydrolysis stabilizers, transesterification stabilizers, (organic) dyes, (organic / inorganic) pigments, also including carbon black and titanium dioxide, compatibilizers, and / or additives for laser marking, particularly in the amounts customary for polycarbonate-based compositions. Such additives are described, for example, in EP 0 839 623 A1, WO 96 / 15102 A1, EP 0 500 496 A1, or in the "Plastics Additives Handbook," Hans Zweifel, 5th Edition 2000, Hanser Verlag, Munich. These additives can be added individually or in admixture.

[0146] Further preferred further additives, if any further additives are present, are only one or more further additives selected from the group consisting of thermal stabilizers, antioxidants, mold release agents, organic dyes, organic pigments, inorganic pigments.

[0147] Very particularly preferably, at least one thermal stabilizer, an antioxidant and / or a mold release agent is included as a further additive.

[0148] It is understood that only such additives and only in such quantities may be added if they do not have a significantly negative impact on the inventive effect of the high CTI in combination with the good flame retardancy and preferably also the Vicat temperature, determined according to ISO 306:2014-3, VST Method B, is not reduced below 105°C, more preferably not below 108°C.

[0149] The compositions according to the invention may contain other flame retardants in addition to component C, but are free from those selected from the group of alkali, alkaline earth, or ammonium salts of aliphatic or aromatic sulfonic acid, sulfonamide, and sulfonimide derivatives, and combinations thereof. "Derivatives" are understood to mean compounds whose molecular structure contains a different atom or group of atoms instead of an H atom or a functional group, or in which one or more atoms / groups of atoms have been removed. The parent compound is thus still recognizable.

[0150] Such flame retardants which are not contained in compositions according to the invention are in particular one or more compounds selected from the group consisting of sodium or potassium perfluorobutane sulfate, sodium or potassium perfluoromethanesulfonate, sodium or potassium perfluorooctane sulfate, sodium or potassium 2,5-dichlorobenzenesulfate, sodium or potassium 2,4,5-trichlorobenzenesulfate, sodium or potassium diphenylsulfonesulfonate, sodium or potassium 2-formylbenzenesulfonate, sodium or potassium (N-benzenesulfonyl)benzenesulfonamide or mixtures thereof, of which particularly preferably sodium or potassium perfluorobutane sulfate, sodium or potassium perfluorooctane sulfate, sodium or potassium diphenylsulfonesulfonate or mixtures thereof, in particular potassium perfluoro-1-butanesulfonate, which is commercially available, inter alia as Bayowet® C4 from Lanxess, Leverkusen, Germany.

[0151] Particularly preferred additives are mold release agents, more preferably based on a fatty acid ester, even more preferably based on a stearic acid ester, and especially preferably based on pentaerythritol. Particular preference is given to using pentaerythritol tetrastearate (PETS) and / or glycerol monostearate (GMS). If one or more mold release agents are used, the amount is preferably up to 1.0 wt.% (inclusive), more preferably 0.01 to 0.7 wt.%, particularly preferably 0.2 to 0.60 wt.%, in each case based on the total composition.

[0152] Particularly preferred additives are also thermal stabilizers. The amount of thermal stabilizer is preferably up to 0.20 wt.%, more preferably 0.01 to 0.15 wt.%, even more preferably 0.01 to 0.1 wt.%, particularly preferably 0.025 to 0.09 wt.%, based on the total composition.

[0153] Phosphorus-based stabilizers selected from the group of phosphates, phosphites, phosphonites, phosphines and their mixtures are particularly suitable as thermal stabilizers. Examples are triphenyl phosphite, diphenyl alkyl phosphite, phenyldialkyl phosphite, tris(nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl phosphite, distearylpentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite (Irgafos® 168), Diisodecylpentaerythritol diphosphite, bis(2,4-di-tert-butylphenyljpentaerythritol diphosphite, bis(2,4-di-cumylphenyl)pentaerythritol diphosphite (Doverphos® S-9228), bis(2,6-di-tert-butyl-4-methylphenyl)penta-erythritol diphosphite, Diisodecyloxy-pentaerythritol diphosphite, Bis(2,4-di-tert-butyl-6-methylphenyl)-pentaerythritol diphosphite,

[0154] Bis(2,4,6-tris(tert-butylphenyl)pentaerythritoldiphosphit, Tristearylsorbitoltriphosphit, Tetrakis(2,4- di-tert-butylphenyl)-4,4'-biphenylendiphosphonit, 6-Isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-di- benz[d,g]-l,3,2-dioxaphosphocin, Bis(2,4-di-tert-butyl-6-methylphenyl)methylphosphit, Bis(2,4-di- tert-butyl-6-methylphenyl)ethylphosphit, 6-Fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]- 1,3,2-dioxaphosphocin, 2,2',2"-Nitrilo-[triethyltris(3,3',5,5'-tetra-tert-butyl-l,l'-biphenyl-2,2'- diyl)phosphit], 2-Ethylhexyl(3,3',5,5'-tetra-tert-butyl-l,l'-biphenyl-2,2'-diyl)phosphit, 5-Butyl-5- ethyl-2-(2,4,6-tri-tert-butylphenoxy)-l,3,2-dioxaphosphiran, Bis(2,6-di-ter-butyl-4-methylphe- nyljpentaerythritol-diphosphit, Triphenylphosphin (TPP), Trialkylphenylphosphin, Bisdiphenylp- hosphino-ethan oder ein Trinaphthylphosphin. Sie werden allein oder im Gemisch, z. B.Irganox® B900 (a mixture of Irgafos® 168 and Irganox® 1076 (antioxidant) in a ratio of 4:1) or Doverphos® S-9228 with Irganox® B900 or Irganox® 1076 are used. Triphenylphosphine (TPP), Irgafos® 168, or tris(nonylphenyl) phosphite, or mixtures thereof, are particularly preferred. Phenolic antioxidants such as alkylated monophenols, alkylated thioalkylphenols, hydroquinones, and alkylated hydroquinones can also be used. Irganox® 1010 (pentaerythritol 3-(4-hydroxy-3,5-di-tert-butylphenyl)propionate; CAS: 6683-19-8) and Irganox 1076® (octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) are particularly preferably used, preferably in amounts of 0.01 - 0.5 wt.%.

[0155] Furthermore, sulfonic acid esters or alkyl phosphates, e.g., mono-, di-, and / or trihexyl phosphate, triisoctyl phosphate, and / or trinonyl phosphate, can be added as transesterification inhibitors. Triisooctyl phosphate (tris-2-ethylhexyl phosphate) is preferably used as the alkyl phosphate. Mixtures of various mono-, di-, and trialkyl phosphates can also be used. Triisooctyl phosphate is preferably used in amounts of 0.003 wt.% to 0.05 wt.%, more preferably 0.005 wt.% to 0.04 wt.%, and particularly preferably 0.01 wt.% to 0.03 wt.%, based on the total composition.

[0156] Examples of impact modifiers include: core-shell polymers such as ABS or MBS; olefin-acrylate copolymers such as Elvaloy® grades from DuPont or Paraloid® grades from Dow; silicone acrylate rubbers such as Metablen® grades from Mitsubishi Rayon Co., Ltd. The compositions of the invention already have an excellent property profile without additional impact modifiers. Compositions of the invention are therefore preferably free of impact modifiers.

[0157] Particularly preferably, no fillers are contained in the compositions according to the invention.

[0158] Preferred compositions according to the invention consist of

[0159] A) at least 68% by weight of aromatic polycarbonate,

[0160] B) 4 wt.% to 25 wt.% (meth)acrylate copolymer, wherein the (meth)acrylate copolymer comprises aromatic (meth)acrylate units b1 and methyl methacrylate units b2 in a weight ratio b1 / b2 of (5 to 20 wt.%) / (80 to 95 wt.%), based on the total weight of the (meth)acrylate copolymer,

[0161] C) 2% to 10% by weight of phosphorus-containing flame retardant,

[0162] D) 0.25 wt.% to 2 wt.% of fluorine-containing anti-drip agent containing polytetrafluoroethylene,

[0163] E) one or more further additives selected from the group consisting of one or more mold release agents, heat stabilizers, antioxidants, dyes, pigments, UV absorbers, IR absorbers, impact modifiers, antistatic agents, optical brighteners, hydrolysis stabilizers, transesterification stabilizers, compatibilizers, additives for laser marking and mixtures thereof, wherein the wt.% figures relate to the total composition and wherein the ratio of the amount of (meth)acrylate copolymer in wt.% and the amount of phosphorus-containing flame retardant in wt.% is < 2.5 and the ratio of the amount of (meth)acrylate copolymer in wt.% and the amount of polytetrafluoroethylene in wt.% is < 20.

[0164] Particularly preferred compositions according to the invention consist of

[0165] A) at least 75% by weight of aromatic polycarbonate,

[0166] B) 5 wt.% to 20 wt.% (meth)acrylate copolymer, wherein the (meth)acrylate copolymer comprises aromatic (meth)acrylate units b1 and methyl methacrylate units b2 in a weight ratio b1 / b2 of (5 to 20 wt.%) / (80 to 95 wt.%), based on the total weight of the (meth)acrylate copolymer,

[0167] C) 2% to 8% by weight of phosphorus-containing flame retardant,

[0168] D) 0.25 wt.% to 2 wt.% of fluorine-containing anti-drip agent containing polytetrafluoroethylene,

[0169] E) 0 to 5% by weight of one or more further additives selected from the group consisting of one or more mold release agents, heat stabilizers, antioxidants, dyes, pigments, UV absorbers, IR absorbers, impact modifiers, optical brighteners, hydrolysis stabilizers, transesterification stabilizers, compatibilizers, additives for laser marking and mixtures thereof, wherein the wt% data relate to the total composition and wherein the ratio of the amount of (meth)acrylate copolymer in wt% and the amount of phosphorus-containing flame retardant in wt% is < 2.5 and the ratio of the amount of (meth)acrylate copolymer in wt% and the amount of polytetrafluoroethylene in wt% is < 20.

[0170] Particularly preferred compositions according to the invention consist of

[0171] A) at least 75% by weight of aromatic polycarbonate,

[0172] B) 5 wt.% to 20 wt.% (meth)acrylate copolymer, wherein the (meth)acrylate copolymer contains aromatic (meth)acrylate units b1 in an amount of 5 to 20 wt.% and methyl methacrylate units b2 in an amount of 80 to 95 wt.%, based on the total weight of the (meth)acrylate copolymer,

[0173] C) 2% to 8% by weight of phosphorus-containing flame retardant,

[0174] D) 0.25 wt.% to 2 wt.% of fluorine-containing anti-drip agent containing polytetrafluoroethylene,

[0175] E) 0 to 5 wt.% of one or more further additives selected from the group consisting of one or more mold-release agents, thermal stabilizers, antioxidants, dyes, pigments and mixtures thereof, wherein the wt.% data refer to the total composition and wherein the ratio of the amount of (meth)acrylate copolymer in wt.% and the amount of phosphorus-containing flame retardant in wt.% is < 2.5 and the ratio of the amount of (meth)acrylate copolymer in wt.% and the amount of polytetrafluoroethylene in wt.% is < 20. Preferably, the phosphorus-containing flame retardant is either an organophosphate, in particular one of the formula (12),

[0176] (12), where q = 1 to 20, in particular 1.0 to 1.2, or a

[0177] Phosphazene of the formula (13g) with k = 1, 2, or 3, including mixtures thereof. It is understood that this is preferably a mixture of different oligomers of this formula, since mixtures are usually commercially available. The phosphorus-containing flame retardant is most preferably one of the formula (12) or (13g), as defined above.

[0178] The polymer compositions according to the invention, comprising the mixed components A, B, C, D, and optionally E, can be prepared using powder premixes. Premixes of granules or granules and powders with the additives according to the invention can also be used. Premixes prepared from solutions of the mixture components in suitable solvents, optionally with homogenization in solution and subsequent removal of the solvent, can also be used. In particular, the additives referred to as component E of the compositions according to the invention can be introduced by known methods or as a masterbatch. The use of masterbatches is particularly preferred for incorporating additives and other constituents, with masterbatches based on the respective polymer matrix being used in particular.

[0179] The compositions according to the invention can, for example, be extruded. After extrusion, the extrudate can be cooled and comminuted. The melt can also be combined and thoroughly mixed in the plasticizing unit of an injection molding machine. In this case, the melt is transferred directly into a molded article in the subsequent step.

[0180] Compositions according to the invention are preferably used for producing molded parts for components in the renewable energy sector, in particular for high-voltage switches, inverters, relays, electronic connectors, electrical connectors, circuit breakers, components for photovoltaic applications, electric motors, heat sinks, chargers or charging plugs for electric vehicles, electrical junction boxes, smart meter housings, miniature disconnect switches, and bus bars. The invention therefore also relates to molded parts that are part of a corresponding component. "Part of a" here means that it can be an individual element of a complex product, a group of components, but that it can also be the entire element, as is conceivable, for example, in the case of an "electronic connector."

[0181] A molded part in the sense of the invention also includes an insulating layer made of the composition according to the invention. Such a layer can be provided, for example, on an inverter as a layer to protect against external influences. Standard insulating materials for inverters are those with a CTI of 600 V. The composition according to the invention can also be used as an insulating layer for other electrical components, e.g., transistors. The insulating layer creates, for example, a secure boundary between the transistor and a metallic heat sink.

[0182] The component is preferably designed for an operating voltage of at least 400 V. However, it can also be designed for a typical household operating voltage of 230 V ± 23 V in Europe, although smaller distances between the electrical conductors can now be realized. The molded part is preferably intended for use in such a way that it itself must have a tracking resistance of at least 600 V, determined as described above.

[0183] The invention thus relates to molded parts consisting of or comprising regions of compositions according to the invention, as well as corresponding components comprising elements, i.e. molded parts which consist of compositions according to the invention or comprise regions consisting of compositions according to the invention.

[0184] The high tracking resistance of the polycarbonate compositions according to the invention makes it possible to realize smaller distances between two electrical conductors of a component using the polycarbonate material than was previously possible using polycarbonate.

[0185] The invention therefore also relates to an EE component, comprising a first electrical conductor and a second electrical conductor at a first distance dl and a second distance d2 from each other, which are connected via an element made of a thermoplastic composition according to the invention which is in direct contact with the first electrical conductor and the second electrical conductor, wherein the distance dl is the shortest distance between the first electrical conductor and the second electrical conductor along the surface of the element made of the thermoplastic composition and wherein the distance d2 is the shortest distance between the first electrical conductor and the second electrical conductor through the air, wherein d2 is selected such that flashover through the air is prevented at the respective operating voltage and wherein dl at the operating voltage U listed below is: dli(0V < U < 250V): 1.3 mm to < 2,5 mm dlii(250 V < U < 500 V) = 2.5 mm to < 5.0 mm dlii(500 V < U < 1000 V) = 5.0 mm to < 10.0 mm.,

[0186] Such low lower limits for the distances between the electrical conductors can only be achieved with a material that has a CTI of at least 600 V. The upper range of these low distance ranges can also only be achieved if the material used has a CTI of at least 400 V.

[0187] Even the distance ranges listed below can only be realized at the specified operating voltages if the material has a CTI of at least 400 V: dli(0V < U < 250V): 1.8 mm to < 2.5 mm dlii(250 V < U < 500 V) = 3.6 mm to < 5.0 mm dliii(500 V < U < 1000 V) = 7.1 mm to < 10.0 mm.

[0188] Particularly preferably, when using a material with a CTI of 600V, as described as part of the invention, dl is at the listed operating voltage: dli(0V < U < 250V): 1.3 mm to < 1.8 mm, dlii(250 V < U < 500 V) = 2.5 mm to < 3.6 mm, dliii(500 V < U < 1000 V) = 5.0 mm to < 7.1 mm, distances which are not realizable even with a material with a CTI of 400 V or 450 V, but require a CTI of 600 V.

[0189] It is therefore possible to produce renewable energy components with polycarbonate material between two electrical conductors with smaller distances than previously thought possible.

[0190] The selection of d2 is within the scope of Bachmann's expertise. Preferably, d2 is at least 1.2 mm. "Element made of a thermoplastic composition according to the invention" here means an element consisting of a thermoplastic composition according to the invention.

[0191] As is well known, the degree of contamination affects electrical conductivity. The specified distances dl and d2 are applicable in practice for components that meet protection class IP6K9K according to ISO 20653:2013-02, e.g., due to structural shielding.

[0192] Thermoplastic compositions preferred according to the invention belong to insulating material group I (600 V < CTI), classified according to DIN EN 60664-1.

[0193] Due to the high tracking resistance of the material used, the EE component according to the invention is preferably used for EE assemblies designed for an operating voltage of at least 400 V, possibly even 600 V. Corresponding EE assemblies are therefore also the subject of the invention.

[0194] Various embodiments of the present invention are described below:

[0195] 1. Thermoplastic composition containing

[0196] A) at least 68% by weight of aromatic polycarbonate,

[0197] B) 4 wt.% to 25 wt.% (meth)acrylate copolymer, wherein the (meth)acrylate copolymer comprises aromatic (meth)acrylate units b1 and methyl methacrylate units b2 in a weight ratio b1 / b2 of (5 to 20 wt.%) / (80 to 95 wt.%), based on the total weight of the (meth)acrylate copolymer,

[0198] C) 2% to 10% by weight of phosphorus-containing flame retardant,

[0199] D) 0.25 wt.% to 2 wt.% fluorine-containing anti-drip agent containing polytetrafluoroethylene,

[0200] E) optionally one or more further additives selected from the group consisting of one or more mold release agents, heat stabilizers, antioxidants, dyes, pigments, UV absorbers, IR absorbers, impact modifiers, antistatic agents, optical brighteners, hydrolysis stabilizers, transesterification stabilizers, compatibilizers, additives for laser marking and mixtures thereof, wherein the wt% data refer to the total composition and wherein the ratio of the amount of (meth)acrylate copolymer in wt% and the amount of phosphorus-containing flame retardant in wt% is < 2.5 and the ratio of the amount of (meth)acrylate copolymer in wt% and the amount of polytetrafluoroethylene in wt% is < 20 and wherein the thermoplastic composition is free of flame retardants selected from the group of alkali, alkaline earth and ammonium salts of aliphatic or aromatic sulfonic acid, Sulfonamide and sulfonimide derivatives.

[0201] 2. Thermoplastic composition according to embodiment 1, wherein the ratio of the amount of (meth)acrylate copolymer in wt.% and the amount of polytetrafluoroethylene in wt.% is < 10.

[0202] 3. Thermoplastic composition according to embodiment 1 or 2, wherein the phosphorus-containing flame retardant is an organophosphate, a phosphazene or a mixture thereof.

[0203] 4. Thermoplastic composition according to one of the preceding embodiments, wherein an organophosphate of formula (11) is present as the phosphorus-containing flame retardant wherein

[0204] R 1 , R 2 , R 3 and R 4each independently of one another represents a linear or branched C1- to C5-alkyl radical and / or optionally linear or branched alkyl-substituted C5- to C10-cycloalkyl radical, C12- to C10-aryl radical or C7- to Cn-aralkyl radical, n independently of one another represents 0 or 1, q independently of one another represents 0, 1, 2, 3 or 4,

[0205] N is a number between 1 and 30,

[0206] Rs and Re are independently linear or branched Ci - to C4-alkyl radical, preferably methyl radical, and

[0207] Y is linear or branched C1- to C2-alkylidene radical, C5- to C1-cycloalkylene radical, C5- to C2-cycloalkylidene radical, -O-, -S-, -SO-, SO2 or -CO-.

[0208] 5. Thermoplastic composition according to one of the preceding embodiments, wherein phosphazene of formula (13g) is present as phosphorus-containing flame retardant with k = 1, 2 or 3, including mixtures thereof.

[0209] 6. Thermoplastic composition according to one of the preceding embodiments, wherein the composition contains 5 to 20 wt.% (meth)acrylate copolymer.

[0210] 7. Thermoplastic composition according to any one of the preceding embodiments, wherein the composition contains 0.3 wt.% to 1.0 wt.% mold release agent.

[0211] 8. Thermoplastic composition according to one of the preceding embodiments, wherein the composition contains a total of 0.02 to 0.15 wt.% of thermal stabilizer and / or antioxidant.

[0212] 9. Thermoplastic composition according to one of the preceding embodiments, wherein the amount of phosphorus-containing flame retardant is 2 to 8 wt.%.

[0213] 10. Thermoplastic composition according to one of the preceding embodiments, wherein component B has a weight-average molecular weight, determined by gel permeation chromatography in tetrahydrofuran under PMMA calibration, of 5,000 to 300,000 g / mol.

[0214] 11. Thermoplastic composition according to one of the preceding embodiments, wherein component B has a weight-average molecular weight, determined by gel permeation chromatography in tetrahydrofuran under PMMA calibration, of 10,000 to 25,000 g / mol.

[0215] 12. Thermoplastic composition according to any one of the preceding embodiments, wherein the aromatic (meth)acrylate is phenyl (meth)acrylate and / or benzyl (meth)acrylate.

[0216] 13. Thermoplastic composition according to one of the preceding embodiments, wherein the thermoplastic composition contains, in addition to components A, B, C and D, as component E only one or more thermal stabilizers, antioxidants, mold release agents, dyes, pigments and mixtures thereof.

[0217] 14. A molded part consisting of or comprising a region of a thermoplastic composition according to any one of the preceding embodiments.

[0218] 15. The molded part according to embodiment 14, wherein the molded part is part of a high-voltage switch, inverter, relay, electronic connector, electrical connector, circuit breaker, photovoltaic system, electric motor, heat sink, electric vehicle charger, electrical junction box, smart meter housing, miniature circuit breaker, busbar.

[0219] 16. Molded part according to embodiment 14 or embodiment 15, wherein the molded part is part of an EE component designed for an operating voltage of at least 375 V.

[0220] 17. Molded part according to one of embodiments 14 to 16, wherein the molded part is part of an EE component designed for an operating voltage of at least 400 V.

[0221] 18. Molded part according to one of embodiments 14 to 17, wherein the molded part is part of an EE component designed for an operating voltage of at least 500 V.

[0222] 19. Molded part according to one of embodiments 14 to 18, wherein the molded part is part of an EE component designed for an operating voltage of at least 600 V.

[0223] 20. An EE component comprising a first electrical conductor and a second electrical conductor at a first distance d1 and a second distance d2 from each other, which are connected via an element made of a thermoplastic composition according to any one of embodiments 1 to 13, which is in direct contact with the first electrical conductor and the second electrical conductor, wherein the distance d1 is the shortest distance between the first electrical conductor and the second electrical conductor along the surface of the element made of the thermoplastic composition and wherein the distance d2 is the shortest distance between the first electrical conductor and the second electrical conductor through the air, wherein d2 is selected such that flashover through the air is prevented at the respective operating voltage and wherein d1 at the operating voltage U listed below is: d1i(0V < U < 250V): 1.3 mm to < 2.5 mm d1i(250V < U < 500V) = 2,5 mm to < 5.0 mm dliii(500 V < U < 1000 V) = 5.0 mm to < 10.0 mm.,

[0224] 21. EE component according to embodiment 20, wherein dl at the operating voltage U listed below is: dli(0V < U < 250V): 1.3 mm to < 1.8 mm, dlii(250 V < U < 500 V) = 2.5 mm to < 3.6 mm, dliii(500 V < U < 1000 V) = 5.0 mm to < 7.1 mm.

[0225] 22. EE component according to one of embodiments 20 or 21, where d2 > 1.2 mm.

[0226] 23. EE component according to one of the embodiments 20 to 22, wherein a degree of protection IP6K9K according to ISO 20653:2013-02 is present.

[0227] 24. EE component according to one of embodiments 20 to 23, designed for an operating voltage of at least 400 V, preferably at least 500 V, particularly preferably at least 600 V.

[0228] 25. EE component according to one of embodiments 20 to 24, wherein the element made of a thermoplastic composition according to one of embodiments 1 to 13 is a molded part according to one of embodiments 14 to 19.

[0229] 26. The EE component according to any one of embodiments 20 to 25, wherein the EE component is part of a high-voltage switch, inverter, relay, electronic connector, electrical connector, circuit breaker, photovoltaic system, electric motor, heat sink, charger or charging plug for electric vehicles, electrical junction box, smart meter housing, miniature circuit breaker, or busbar.

[0230] 27. Use of the combination of 4 to 25 wt.% (meth)acrylate copolymer, wherein the (meth)acrylate copolymer comprises aromatic (meth)acrylate units b1 and methyl methacrylate units b2 in a weight ratio b1 / b2 of (5 to 20 wt.%) / (80 to 95 wt.%), based on the total weight of the (meth)acrylate copolymer, 0.25 to 2 wt.% fluorine-containing anti-drip agent containing polytetrafluoroethylene, and 2 to 10 wt.%, preferably 2 to 8 wt.% phosphorus-containing flame retardant, wherein the wt.% data refer to the resulting total composition and wherein the wt.% data refer to the total composition and wherein the ratio of the amount of (meth)acrylate copolymer in wt.% and the amount of phosphorus-containing flame retardant in wt.% is < 2.5 and the ratio of the Amount of (meth)acrylate copolymer in wt.% and the amount of polytetrafluoroethylene in wt.-% < 20, to achieve a CTI of 600V and a UL94 VO classification at 2 mm for a thermoplastic polycarbonate-based composition.

[0231] 28. An EE assembly comprising an EE component according to any one of embodiments 20 to 26, wherein the EE assembly has a degree of protection IP6K9K according to ISO 20653:2013-02.

[0232] 29. Thermoplastic composition according to any one of embodiments 1 to 13, molded part according to any one of embodiments 14 to 19, EE component according to any one of embodiments 20 to 26, use according to embodiment 29 or EE assembly according to embodiment 28, wherein the aromatic polycarbonate is bisphenol A-based homopolycarbonate.

[0233] Examples

[0234] 1. Description of raw materials and test methods a) Raw materials

[0235] Component Al: Linear polycarbonate based on bisphenol A with a melt volume flow rate of 12 cm 3 / (10 min) (according to ISO 1133:2012-03, at a test temperature of 300°C and 1.2 kg load), containing as component E-3 250 ppm (= 0.025 wt.%, based on the total weight of component A) thermal stabilizer triphenylphosphine.

[0236] Component A-2: Linear polycarbonate based on bisphenol A with a melt volume flow rate of 6 cm 3 / (10 min) (according to ISO 1133:2012-03, at a test temperature of 300°C and a load of 1.2 kg).

[0237] Component Bl: (Meth)acrylate copolymer, trade name Metabien H-881 from Mitsubishi Rayon, containing approximately 10 wt.% aromatic acrylate component.

[0238] Component Cl: Organophosphate of formula (12) with q = 1.0 - 1.2. Bisphenol A bis(diphenyl phosphate) from Adeka.

[0239] Component C-2: Phenoxycyclophosphazene Rabitle FP110 from Fushimi Pharmaceutical, Japan, formula (13g), with a trimer content (k = 1) of about 68 mol%.

[0240] Component C-3*: Potassium perfluoro-1-butanesulfonate, commercially available as Bayowet® C4 from Lanxess AG, Leverkusen, Germany, CAS No. 29420-49-3. Component D1: SAN-encapsulated polytetrafluoroethylene ADS5000 (approximately 50 wt.% PTFE (fluorine-containing anti-drip agent) and approx. 50 wt.% SAN) from Chemical Innovation Co., Ltd., Thailand.

[0241] Component D-2: Polytetrafluoroethylene Teflon CFP6000X from Chemours Netherlands BV

[0242] Component El: Mold release agent. Pentaerythritol tetrastearate, commercially available as Loxiol VPG 861 from Emery Oleochemicals Group.

[0243] Component E-2: Mixture of thermal stabilizer and antioxidant. Irganox® B900 from BASF (mixture of Irgafos® 168 (tris-(2,4-di-tert-butylphenyl) phosphite) and Irganox® 1076 (octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) in a weight ratio of 4:1). b) Test methods

[0244] Comparative tracking index (CTI):

[0245] To determine the tracking resistance, the compositions described here were tested according to the Sehne test method based on IEC 60112:2009. For this purpose, a 0.1% ammonium chloride test solution (395 ohm* cm resistance) was applied dropwise between two electrodes spaced 4 mm apart onto the surface of test specimens measuring 60 mm x 40 mm x 4 mm at intervals of 30 s. A test voltage was applied between the electrodes, which varied over the course of the test. The first test specimen was tested at a starting voltage of 300 V or 350 V. A maximum of 50 drops (one drop every 30 s) were applied per voltage, provided no tracking current > 0.5 A occurred over 2 s or the specimen burned. After 50 drops, the voltage was increased by 50 V and a new test specimen was tested at this higher voltage, according to the procedure described above.This process was continued until either 600 V was reached or leakage current or fire occurred. If one of the aforementioned effects occurred with fewer than 50 drops, the voltage was reduced by 25 V and a new test specimen was tested at this lower voltage. The voltage was reduced until the test passed with 50 drops without leakage current or fire. This procedure determined the maximum possible voltage at which a composition could withstand 50 drops of the test solution without leakage current occurring. Finally, four more test specimens, each with 50 drops, were tested at the maximum voltage determined for confirmation. This confirmed value is given in the examples as the CTI. A 100-drop value was not determined, hence the “rapid test method based on” the aforementioned standard.

[0246] PTI (“proof tracking index”):

[0247] The PTI is tested based on IEC 60112:2009, modified as described below. For this purpose, a 0.1% ammonium chloride test solution (395 ohm* cm resistance) was applied dropwise between two electrodes spaced 4 mm apart onto the surface of test specimens measuring 60 mm x 40 mm x 4 mm at intervals of 30 seconds. In contrast to the CTI test, a fixed test voltage is applied between the electrodes during the PTI test, and a total of five test specimens are tested at the respective voltage. A maximum of 50 drops (one drop every 30 seconds) were applied per test specimen, provided no leakage current > 0.5 A occurred for 2 seconds or the specimen burned.

[0248] Flame resistance:

[0249] The flame retardancy test of the polycarbonate compositions was conducted according to Underwriter Laboratory Method UL 94 V at a thickness of 2 mm. The specified flammability class is derived from the individual tests after 48 hours and 168 hours of standard conditioning.

[0250] Different fire classes are assigned based on the behavior of the test specimens. These include the time until the flame extinguishes, resistance to dripping, and whether a material drips while burning. The classes determined based on these criteria are designated V0, VI, and V2 and are determined based on a total of five tested specimens.

[0251] V0: The test specimen, positioned with its longitudinal axis 180° (vertical) to the flame, has an average afterburn time of no more than 10 seconds after the flame is removed and does not produce dripping plastic particles that could ignite cotton wool underneath the test specimen. The total afterburn time of five test specimens, each exposed to the flame twice, is a maximum of 50 seconds.

[0252] VI: In contrast to V0, the average maximum afterburn time here is < 30 seconds, whereby no particles are allowed to drop off and ignite the cotton wool. The total afterburn time of five test specimens, each exposed to flame twice, is < 250 seconds.

[0253] V2: In contrast to V0 and VI, this classification produces dripping plastic particles that ignite the cotton wool. The individual afterburn times are < 30 seconds, and the total afterburn time of five test specimens, each exposed to flame twice, is < 250 seconds. NB: The test does not provide a flame retardant classification if the afterburn times are exceeded.

[0254] Heat resistance:

[0255] The heat distortion temperature of the compositions was determined using the Vicat softening temperature (Method B, test force 50 N, heating rate 50 K / h) on test specimens measuring 80 mm x 10 mm x 4 mm according to ISO 306:2014-3. 2. Preparation of the test specimens

[0256] The compositions were produced on a 25 mm Coperion twin-screw extruder with a throughput of 20 kg / h. The polymer melt temperatures in the extruder ranged from 260 to 280°C at an average screw speed of 225 rpm.

[0257] The test specimens with dimensions of 60 mm x 40 mm x 4 mm were manufactured from the molding compounds using standard injection molding processes at a melt temperature of 280°C and a mold temperature of 80°C.

[0258] 3. Results

[0259] In the following tables, “ng” means “not tested” and “nb” means “failed”.

[0260] The note “*” means: “taken from UL Yellow Card.”

[0261] Table 1 ng : not tested, nb : failed

[0262] Tables 1 - 3 include polycarbonate compositions with 5 - 20 wt.% polymethacrylate copolymer B1. Even small amounts of component B1 surprisingly led to a significant improvement in the tracking resistance of the polycarbonate with intrinsically poor tracking resistance (compare V-2 with V-3). The robust tracking resistance of this composition is demonstrated by the successful PTI tests in the medium voltage range of 300 - 350 V. This range is particularly critical and usually the reason for failure in the CTI test. If a material can successfully pass this voltage range, the probability of a high CTI of, for example, 600 V is very high. However, a VO classification according to UL94 at 2 mm can only be achieved by adding additional flame retardant and anti-drip agents (E-4 to E-6). Even larger amounts of the polymethylmethacrylate copolymer B1 continue to have a positive effect on the CTI (seeTable 2), whereby the comparative examples V-8 and V-9 clearly show that the choice of flame retardant is crucial. Even the smallest amounts of inorganic sulfonate (component C-3*) lead to material failure in the CTI test. Even larger amounts of otherwise suitable phosphorus-based flame retardants (components C1 and C-2) have a negative impact on the CTI (see V-17 and V-22). The results in Table 2 also clearly show that without the addition of an anti-drip agent, a VO classification according to UL94 cannot be achieved (see V-11, V-15, V-18, V-20), even with large amounts of flame retardant (cf. V-17 and V-22). The optimal amount of anti-drip agent depends on the amount of polymethyl methacrylate copolymer B1. Larger amounts of polymethyl methacrylate copolymer generally require larger amounts of PTFE-containing anti-drip agent (compare, for example, E-5 with V-12 and E-13).With a 10 wt% PMMA component, 1 wt% PTFE (component D-2) or the corresponding 2 wt% of the 50:50 PTFE:SAN masterbatch D1 is required for VO classification (see E-13 to E-21). The optimal amount of flame retardant is above 2 wt% and, as described above, below 12 wt%, with the heat resistance decreasing with increasing amount. With amounts of polymethylmethacrylate copolymer in the range of 20 wt%, it becomes increasingly difficult to render the composition sufficiently flame-retardant, which has a noticeable impact on the heat resistance (see Table 3).

[0263] Table 2

[0264] Table 3 ng: not tested, nb: failed

Claims

Patent claims:

1. Thermoplastic composition containing A) at least 68% by weight aromatic polycarbonate, B) 4 wt.% to 25 wt.% (meth)acrylate copolymer, wherein the (meth)acrylate copolymer comprises aromatic (meth)acrylate units b1 and methyl methacrylate units b2 in a weight ratio bl / b2 of (5 to 20 wt.%) / (80 to 95 wt.%), based on the total weight of the (meth)acrylate copolymer, C) 2% to 10% by weight phosphorus-containing flame retardant, D) 0.25 wt.% to 2 wt.% fluorinated anti-drip agent containing polytetrafluoroethylene, wherein the wt.% values ​​refer to the total composition and wherein the ratio of the amount of (meth)acrylate copolymer in wt.% to the amount of phosphorus-containing flame retardant in wt.% is < 2.5 and the ratio of the amount of (meth)acrylate copolymer in wt.% to the amount of polytetrafluoroethylene in wt.% is < 20 and wherein the thermoplastic composition is free of flame retardants selected from the group of alkali, alkaline earth and ammonium salts of aliphatic or aromatic sulfonic acid, sulfonamide and sulfonimide derivatives.

2. Thermoplastic composition according to claim 1, wherein the amount of phosphorus-containing flame retardant is 2 wt.% to 8 wt.%.

3. Thermoplastic composition according to any of the preceding claims, wherein the aromatic polycarbonate is bisphenol A homopolycarbonate.

4. Thermoplastic composition according to any of the preceding claims, wherein the composition contains 5 to 20 wt.% (meth)acrylate copolymer.

5. Thermoplastic composition according to any of the preceding claims, wherein the phosphorus-containing flame retardant is an organophosphate, a phosphazene or a mixture thereof.

6. Thermoplastic composition according to any one of the preceding claims, wherein phosphazene of formula (13g) is included as the phosphorus-containing flame retardant. with k = 1, 2 or 3, including mixtures thereof. Thermoplastic composition according to any one of the preceding claims, wherein the phosphorus-containing flame retardant is an organophosphate of formula (11). wherein R 1 , R 2 , R 3 and R 4each independently a linear or branched Ci to Cs alkyl group and / or optionally by linear or branched alkyl-substituted C5 to Ce cycloalkyl group, Ce to Cio aryl group or C7 to Cn aralkyl group, n independently 0 or 1, q independently 0, 1, 2, 3 or 4, N is a number between 1 and 30, Rs and ; independently of each other linear or branched Ci to C4 alkyl group, preferably methyl group, and Y linear or branched Ci- to Cy-alkylidate group. A linear or branched Ci- to C7-alkylene residue, C5- to Ci2-cycloalkylene residue, C5- to Ci2-cycloalkylidene residue, -O-, -S-, -SO-, SO2- or -CO-. Thermoplastic composition according to any one of the preceding claims, further optionally comprising E) one or more further additives selected from the group consisting of one or more release agents, thermostabilizers, antioxidants, dyes, pigments, UV absorbers, IR absorbers, impact modifiers, antistatic agents, optical brighteners, hydrolysis stabilizers, transesterification stabilizers, compatibility enhancers, laser marking additives and mixtures thereof, the composition consists of components A to D and, if applicable, E.

9. Thermoplastic composition according to any of the preceding claims, wherein the thermoplastic composition contains, in addition to components A, B, C and D, only one or more thermostabilizers, antioxidants, release agents, dyes, pigments and mixtures thereof.

10. Molded part consisting of or comprising a region of a thermoplastic composition according to any of the preceding claims.

11. Molded part according to claim 10, wherein the molded part is part of a high-voltage switch, inverter, relay, electronic connector, electrical connector, circuit breaker, photovoltaic system, electric motor, heat sink, charger or charging plug for electric vehicles, electrical junction box, smart meter housing, miniature disconnect switch, or current busbar.

12. EE component comprising a molded part according to claim 10 or 11 or a layer of a thermoplastic composition according to any one of claims 1 to 9.

13. EE component according to claim 12, comprising a first electrical conductor and a second electrical conductor at a first distance dl and a second distance d2 from each other, which are connected via a thermoplastic composition according to any one of claims 1 to 10, which is in direct contact with the first electrical conductor and the second electrical conductor, wherein the distance dl is the shortest distance between the first electrical conductor and the second electrical conductor along the surface of the thermoplastic material M, and wherein the distance d2 is the shortest distance between the first electrical conductor and the second electrical conductor through the air, wherein d2 is selected such that arcing through the air is prevented at the respective operating voltage, wherein dl is, at the following operating voltage U, as follows: dli(0V < U < 250V): 1.3 mm to < 2.5 mm; dlii(250V < U < 500V): 2.5 mm to < 5.0 mm dliii(500 V < U < 1000 V) = 5.0 mm to < 10.0 mm., 14. Use of the combination of 4 wt.% to 25 wt.% (meth)acrylate copolymer, wherein the (meth)acrylate copolymer comprises aromatic (meth)acrylate units b1 and methyl methacrylate units b2 in a weight ratio bl / b2 of (5 to 20 wt.%) / (80 to 95 wt.%), based on the total weight of the (meth)acrylate copolymer, 2 wt.% to 10 wt.% phosphorus-containing flame retardant, 0.25 wt.% to 2 wt.% fluorinated anti-drip agent, containing polytetrafluoroethylene, wherein the wt.% values ​​refer to the resulting total composition and wherein the ratio of the amount of (meth)acrylate copolymer in wt.% to the amount of phosphorus-containing flame retardant in wt.% is < 2.5 and the ratio of the amount of (meth)acrylate copolymer in wt.% to the amount of polytetrafluoroethylene in wt.% is < 20, to achieve a CTI, determined in accordance with IEC 60112:2009, of 600 V and a UL94 V0 classification at 2 mm for a thermoplastic, aromatic polycarbonate-based composition.

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