Thermally conductive flame-proof polycarbonate compositions having a high comparative tracking index

Abstract

Described are thermally conductive flame-proof compositions which have a high comparative tracking index and contain bisphenol A homopolycarbonate, talc, phosphorus-containing flame retardant, fluorine-containing anti-drip agent, and anhydride-modified alpha-olefin polymer. Said compositions have a high comparative tracking index, thus allowing distances between electrical conductors in electronic and electrical components to be kept shorter than in the past.

Description

[0001] Flame-retardant, thermally conductive polycarbonate compositions with high tracking resistance

[0002] The invention relates to thermally conductive, 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 ideal for a wide range of applications, including electrical and electronic components. Good insulating properties and high flame retardancy are essential safety-related requirements for materials used in this field.

[0004] In applications where the plastic is in direct contact with the electrical conductors, high resistance to creeping currents under voltage load is required to prevent short circuits and thus fire within the component. Comparative tracking index (CTI) generally describes the resistance of a plastic material to environmental influences. The CTI value is a measure of the tendency of a plastic to form electrically conductive paths on the surface when exposed to environmental influences such as moisture and contamination, thereby promoting the resulting electrical creepage 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 modern electromobility applications.A further advantage of materials with a high CTI value is the possibility of placing electrical conductors closer together in an EE component without risking a short circuit, which in turn enables the reduction of component dimensions and thus more compact designs and weight savings.

[0005] Polycarbonate itself, in contrast to other thermoplastic polymers such as polystyrene, polyester, etc., has a very low tracking resistance with 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 around 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 higher CTI of the materials used is required for safety reasons. Therefore, polycarbonate has not yet been considered as a material for a wide range of applications that require high tracking resistance. For applications that require high tracking resistance, the materials must also simultaneously exhibit high flame retardancy, i.e.have a VO classification according to UL94V, especially with thin walls.

[0006] Pure polycarbonate typically already possesses a certain degree of intrinsic flame retardancy (V2 classification according to UL94V), 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. With the addition of appropriate flame retardant additives, the flame retardancy of polycarbonate can generally be adjusted very effectively. However, 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.

[0007] WO 2020 / 212245 A1, for example, describes thermally conductive, polycarbonate-based compositions containing 50 to 75 wt.% aromatic polycarbonate, 15 to 35 wt.% talc, 0.5 to 3 wt.% anhydride-modified alpha-olefin polymer, 0.4 to 0.6 wt.% fluorine-containing anti-drip agent, 3 to 10 wt.% phosphazene or 3 to 5 wt.% phosphoric acid ester and 3 to 10 wt.% barium sulfate, which is included as a flame retardant synergist.

[0008] However, 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 achieving high tracking resistance and good flame retardancy in a polycarbonate material.

[0009] Materials with high tracking resistance are particularly needed in electronic components and power-carrying devices. Any current flow is associated with the generation of heat, which increases with increasing power. To prevent technical failure and thus ensure the longevity of such components, it is necessary that the generated heat is adequately dissipated. It would be desirable to develop a polycarbonate material that exhibits higher tracking resistance and flame resistance while also contributing to heat dissipation.

[0010] Thermally conductive polycarbonate material is generally known from the prior art. WO 2018 / 037037 A1 describes corresponding compositions that exhibit improved thermal conductivity due to the use of talc. The addition of maleic anhydride-modified olefin wax largely suppresses basic polymer degradation by the talc, resulting in a material with advantageous mechanical properties. However, such a material lacks good flame retardancy, and its tracking resistance is not significantly increased compared to pure polycarbonate. Until now, experts also believed that no polycarbonate materials with high tracking resistance exist.

[0011] The object was therefore to provide thermally conductive polycarbonate-based compositions that have a high CTI of at least 400 V, preferably of at least 450 V, preferably determined according to the rapid test method based on IEC 60112:2009, and preferably also achieve a UL94 VO classification at 2 mm. The thermal conductivity (in plane) should preferably be at least 1.0 W / (mK), determined according to ASTM E 1461-13. Due to the range of applications and the heat generation in EE components, the compositions should preferably also have good heat distortion temperature, in particular a Vicat softening temperature, determined according to ISO 306:2014-3, VST Method B, of at least 110°C, preferably of at least 112°C, particularly preferably of at least 115°C.

[0012] Surprisingly, it has been shown that an improvement in tracking resistance can be achieved by the addition of talc and that the solution to the problem of providing compositions with the above complex property profile is achieved by combining aromatic polycarbonate with talc and with phosphorus-containing flame retardant, with anti-drip agent, and anhydride-modified a-olefin polymer, each in selected quantity ranges.

[0013] The invention thus relates to a thermoplastic composition containing

[0014] A) at least 50% by weight of bisphenol A homopolycarbonate,

[0015] B) 32 to 37 wt% talc,

[0016] C) 4 to 10 wt.% phosphorus-containing flame retardant,

[0017] D) 0.3 to 2 wt.% fluorine-containing anti-drip agent,

[0018] E) 1 to 3 wt.% anhydride-modified a-olefin polymer, wherein the composition contains no further fillers.

[0019] In addition to components A, B, C, D and E, the composition according to the invention can contain further components, for example further additives in the form of component F. The composition can also contain one or more further thermoplastics other than the above-mentioned components as blend partners (component G), which are not covered by any of components A to F. In the context of the present invention, the stated % by weight of components A, B, C, D, E, optionally F and optionally G - unless explicitly stated otherwise - are each based on the total weight of the composition. It is understood that all components contained in a composition according to the invention together make up 100 % by weight. If the upper limit for a numerical range is specified as "up to X", this includes the stated numerical value with its rounding range upwards.

[0020] Thermoplastic polymers different from components A, E and F that are suitable as blend partners are, for example, further aromatic polycarbonate that is not a bisphenol A homopolycarbonate, i.e. different from component A, polystyrene, styrene copolymers, aromatic polyesters such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), PET-cyclohexanedimethanol copolymer (PETG), polyethylene naphthalate (PEN), PMMA and PMMA copolymers, PMMI, polyolefins such as polyethylene or polypropylene and copolymers with styrene such as transparent polystyrene acrylonitrile (PSAN) or also thermoplastic polyurethanes.

[0021] Very particularly preferably, the above-described compositions do not contain any further components, but the amounts of components A, B, C, D, E, optionally F, optionally G, in particular in the preferred embodiments described, add up to 100% by weight, ie the compositions according to the invention consist of components A, B, C, D, E, optionally F, optionally G, extremely preferably of components A to F.

[0022] 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 a closed formulation of the composition.

[0023] 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 expediently used preferably has a tracking resistance of at least 400 V, in particular at least 450 V, determined as described above according to the rapid test method based on IEC 60112:2009.

[0024] 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 400 V, more preferably at 450 V. The test is preferably carried out according to the rapid test method described in the description section based on IEC 60112:2009. In addition, the compositions according to the invention have a flame retardancy rating of VO according to UL94V in test specimen thicknesses of 2 mm. In addition to the high CTI and good flame retardancy, the compositions preferably also have good heat distortion temperature, which is demonstrated by a Vicat softening temperature, determined according to ISO 306:2014-3, VST Method B, of at least 110°C, preferably of at least 112°C, in particular of 115°C.

[0025] The individual components of the compositions according to the invention are explained in more detail below:

[0026] Component A

[0027] Component A of the thermoplastic compositions according to the invention is bisphenol A homopolycarbonate, i.e. an aromatic polycarbonate based on the sole monomer building block bisphenol A.

[0028] The melt volume flow rate MVR of the aromatic bisphenol A homopolycarbonate 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 to 21 cm 3 / (10 min), particularly preferably 10 to 19 cm 3 / (10 min), most preferably 11 to 15 cm 3 / (10 min).

[0029] 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.

[0030] 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.

[0031] In the case of bisphenol A homopolycarbonate, only bisphenol A is used as the dihydroxyaryl compound. Phenols are preferred chain terminators in the preparation of bisphenol A homopolycarbonate. These phenols are mono- or polysubstituted with C 1 -C 4 alkyl radicals, linear or branched, preferably unsubstituted, or substituted with tert-butyl. Particularly preferred chain terminators are phenol, cumylphenol, and / or p-tert-butylphenol. 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.

[0032] In principle, the homopolycarbonate can also be branched.

[0033] 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.

[0034] Suitable branching agents are, for example, l,3,5-tri-(4-hydroxyphenyl)-benzene, 1,1,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.

[0035] The amount of branching agents to be used optionally is preferably 0.05 mol% to 2.00 mol%, based on moles of bisphenol A used in each case.

[0036] The branching agents can either be added together with the bisphenol A 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 bisphenol A.

[0037] In principle, further aromatic polycarbonates can also be included in the compositions according to the invention as additional blend partners according to component G, as long as they do not have a negative effect on the property profile of high tracking resistance and also good flame retardancy at 2 mm desired according to the invention and also do not lower the Vicat temperature too far, ie preferably not below a Vicat temperature of 110°C, preferably not below 112°C, in particular not below 115°C.

[0038] The thermoplastic compositions according to the invention contain at least 50% by weight, preferably at least 54% by weight, of aromatic bisphenol A homopolycarbonate, i.e., they are based on aromatic polycarbonate. Component B

[0039] Talc in the sense of the present invention is preferably a talc which has essentially the same chemical composition, particle diameter, porosity and / or BET surface area, or a talc mixture.

[0040] Talc is generally a phyllosilicate. It can be described as magnesium silicate hydrate with the general chemical composition Mg3[Si4O10(OH)2]. However, different types of talc contain different impurities, so deviations from this general composition may occur.

[0041] The talc or talc mixture used to produce the composition according to the invention can be sized or unsized. The talc is preferably unsized. For the purposes of the present invention, a sizing is considered to be a targeted (chemi- or physisorption) enrichment of molecules on the surface. Unsized talc is therefore talc that has not been surface-treated, i.e., after obtaining the talc particles with the desired particle diameter and optionally compacting, the talc has preferably not been subjected to any further process step that specifically alters the surface of the talc through chemisorption and / or physisorption.However, this does not exclude the possibility that impurities, dust or similar particles may inadvertently reach parts of the surface during further handling of the talc, as long as the surface of the talc does not significantly lose its properties, particularly with regard to pH.

[0042] The talc preferably has a pH of 8 to 10, more preferably 8.5 to 9.8, and most preferably 9.0 to 9.7, with the pH being determined according to EN ISO 787-9: 1995. It should be noted that EN ISO 787-9: 1995 also mentions the possibility of adding ethanol or other organic solvents to improve the dispersion of the solid to be measured. According to the invention, only distilled water is preferably used to determine the pH according to EN ISO 787-9: 1995.

[0043] Component B, the talc, preferably has an iron(II) oxide and / or iron(III) oxide content of 0.2 to 2.5 wt.%, particularly preferably 0.3 to 2.3 wt.%, most preferably 0.3 to 2.0 wt.%. This content is preferably measured by X-ray fluorescence or atomic absorption spectroscopy. The iron oxide content in the talc influences the degree of degradation of the polycarbonate. It is advantageous to use talc with the specified iron oxide content.

[0044] Likewise preferably, component B has an aluminum oxide content of 0.01 to 0.5 wt. %, particularly preferably 0.05 to 0.48 wt. %, most preferably 0.15 to 0.45 wt. %. Component B preferably has an average particle diameter D50 of 0.01 to 10 μm, particularly preferably 0.25 to 10.00 μm, furthermore preferably 0.5 to 10.00 μm, particularly preferably 1 to 5 μm, wherein the particle diameter D50 is determined by sedimentation analysis. The average value D50 is understood by those skilled in the art to mean an average particle diameter at which 50% of the particles are smaller than the defined value. The particle diameter D50 is preferably determined according to 18013317-3:2001.

[0045] Component B preferably has a BET surface area of ​​7.5 to 20.0 m 2 / g, particularly preferably from 9.0 to 15.0 m 2 / g, most preferably 9.5 to 14.0 m 2 / g. The determination of the surface area according to Brunauer, Emmett, and Teller using gas adsorption is known per se to those skilled in the art. The BET surface area is preferably determined according to ISO 4652:2012-06. This preferred BET surface area is particularly preferably associated with the average particle diameter D50 of the talc described above. It has been found that with such a combination, component B used according to the invention is optimally matched to component C used according to the invention. Due to the special acid number and molar mass of component E, the degradation of the polycarbonate caused by component B can be minimized.

[0046] The talc particularly preferably has a talc content of > 96 wt.%, particularly preferably > 97 wt.%, very particularly preferably > 98 wt.%.

[0047] It is also preferred that the talc has a loss on ignition at 1050 °C of 5.0 to 7.0 wt.%, particularly preferably 5.2 to 6.5 wt.%, and most preferably 5.3 to 6.2 wt.%. The loss on ignition is preferably determined using DIN 51081:2002.

[0048] The talc, which may also be a talc mixture, according to component B is preferably compacted. If a talc mixture is involved, the above figures refer to the talc mixture, i.e., component B in its entirety.

[0049] The compositions according to the invention have a talc content of 32 to 37% by weight, preferably 34 to 36% by weight, particularly preferably 34.5 to 35.5% by weight, based on the total composition.

[0050] Component C

[0051] 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.

[0052] Preferred phosphorus-containing flame retardants are cyclic phosphazenes, phosphorus compounds of formula (10) and mixtures thereof:

[0053] (10), wherein

[0054] R 1 , R 2 , R 3 and R 4 independently of one another represent a C1- to C5-alkyl radical, in each case optionally halogenated and in each case branched or unbranched, and / or C5- to C12-cycloalkyl radical, C12- to C20-aryl radical or C7- to C12-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 represents 0 or 1, q represents a value from 0 to 30 and

[0055] 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, each of which may be substituted or unsubstituted, bridged or unbridged.

[0056] 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 R 4 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.

[0057] X in formula (10) is preferably derived from dihydroxyaryl compounds.

[0058] X in formula (10) particularly preferably represents

[0059] (Xi) (X11)

[0060] (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. Particularly preferably, X is derived from bisphenol A. n in formula (10) is preferably 1. q is preferably 0 to 20, particularly preferably 0 to 10, and in the case of mixtures, average values ​​are from 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.

[0061] As a phosphorus compound of the general formula (10), a compound of the formula (11) is preferred: wherein

[0062] R 1 , R 2 , R 3 and R4 each 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,

[0063] N is a number between 1 and 30,

[0064] Rs and Re independently of one another are linear or branched Ci- to C4-alkyl radical, preferably methyl radical, and

[0065] 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-.

[0066] 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 when using phosphorus compounds of formula (10).

[0067] Further preference is given to using mixtures with the same structure and different ketene lengths, where the stated q-value is the average q-value. The average 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 average q values ​​therefrom. 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 particularly preferably present in the compositions according to the invention.

[0068] 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).

[0069] Alternatively, cyclic phosphazenes according to formula (13) are particularly preferably used as component C:

[0070] (13), where

[0071] R is the same or different and for

[0072] - an amine residue,

[0073] - an optionally halogenated, preferably fluorine-halogenated, more preferably monohalogenated, Ci- to Cs-alkyl radical, preferably methyl, ethyl, propyl or butyl radical,

[0074] - a Ci to Cs alkoxy radical, preferably a methoxy radical, ethoxy radical, propoxy radical or butoxy radical,

[0075] - a C5- to C20-cycloalkyl radical, each optionally substituted by alkyl, preferably C1- to C4-alkyl, and / or halogen, preferably chlorine and / or bromine, - a C1- to C20-aryloxy radical, each optionally substituted by alkyl, preferably C1- to C4-alkyl, and / or halogen, preferably chlorine, bromine, and / or hydroxy-substituted, preferably phenoxy radical, naphthyloxy radical,

[0076] - 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

[0077] - a halogen radical, preferably chlorine or fluorine, or

[0078] - represents an OH radical, k represents an integer from 1 to 10, preferably a number from 1 to 8, particularly preferably 1 to 5, most particularly preferably 1.

[0079] Commercially available phosphazenes are preferred. These are usually mixtures of rings with different ring sizes.

[0080] Further preferred are, both individually and in mixtures: propoxyphosphazene, phenoxyphosphazene, methylphenoxyphosphazene, aminophosphazene, fluoroalkylphosphazenes and phosphazenes of the following structures:

[0081] In the compounds 13a-f shown above, k = 1, 2 or 3. 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.

[0082] 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.

[0083] In one embodiment, only phosphazenes with the same R are used.

[0084] 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%.

[0085] 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%.

[0086] 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%.

[0087] More preferably, the phosphazenes of component C fulfill all three of the above-mentioned conditions with regard to the proportions of oligomers.

[0088] 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.%.

[0089] 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.

[0090] 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).

[0091] The phosphazenes and their preparation are described, for example, in EP 728 811 A2, DE 1961668 A and WO 97 / 40092 A1.

[0092] 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).

[0093] Particularly preferably, component C comprises bisphenol-A-based oligophosphate according to formula (12) and / or cyclic phosphazene according to formula (13), very particularly preferably component C is bisphenol-A-based oligophosphate according to formula (12) and / or cyclic phosphazene according to formula (13), extremely preferably component C is cyclic phosphazene according to formula (13).

[0094] The proportion of phosphorus-containing flame retardant in the compositions according to the invention is 4 wt.% to 10 wt.%, preferably 5 wt.% to 8 wt.%, particularly preferably 5.0 to 8.0 wt.%, based on the total composition.

[0095] The higher the amount of phosphorus-containing flame retardant used, the lower the Vicat temperature is. At amounts above 10 wt.%, the Vicat temperature is reduced to such an extent that applications for which polycarbonate can be used due to its inherently high heat resistance can no longer be served by the material.

[0096] Component D

[0097] The compositions according to the invention contain, as component D, a fluorine-containing anti-drip agent, which may be a mixture of several anti-drip agents. The total amount of anti-drip agent is 0.3 wt.% to 2 wt.%, preferably 0.3 wt.% to 1.0 wt.%, particularly preferably 0.4 wt.% to 0.7 wt.%, based on the total composition, of at least one anti-drip agent.

[0098] Fluorine-containing polymer, in particular polyolefin, is preferably used as the anti-drip agent.

[0099] 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, 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, Me Graw-Hill, Inc., New York, pages 134 and 774; “Modem Plastics Encyclopedia”, 1975-1976, October 1975, Volume 52, No. 10 A, Me Graw-Hill, Inc., New York, pages 27, 28 and 472 and US Pat. No. 3,671 487 A, 3 723 373 A and 3 838 092 A).They can be prepared by known processes, for example by polymerization of tetrafluoroethylene in an aqueous medium with a free radical-forming catalyst, for example sodium, potassium or ammonium peroxydisulfate, 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.

[0100] 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.

[0101] Suitable tetrafluoroethylene polymer powders are commercially available products and are offered, for example, by DuPont under the trade name Teflon®.

[0102] Polytetrafluoroethylene (PTFE) is particularly preferably used as a fluorine-containing anti-drip agent, either as such or in the form of a PTFE-containing composition. If a PTFE-containing composition is used as a fluorine-containing anti-drip agent, its minimum use amount is such that at least 0.2 wt.%, preferably at least 0.21 wt.%, and particularly preferably at least 0.25 wt.% of 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 particularly preferred as the fluorine-containing anti-drip agent; PTFE or PTFE / SAN is most preferred as the fluorine-containing anti-drip agent.

[0103] Component E

[0104] Component E of the compositions according to the invention is an anhydride-modified a-olefin polymer.

[0105] The α-olefin polymer is preferably based on at least one monomer selected from the group consisting of ethylene, 1-propene, 1-butene, 1-isobutene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-octadecene, and 1-nonadecene, but can also be based on mixtures of these monomers. More preferably, the α-olefin polymer is based on at least one monomer selected from the group consisting of ethene, propene, 1-hexene, and 1-octene. The α-olefin polymer is particularly preferably based on ethylene, propene, and / or 1-octene.

[0106] "Based on" in this context means that preferably at least 90% by weight, more preferably at least 95% by weight, particularly preferably at least 98% by weight, based on the total weight of the respective α-olefin polymer, without anhydride modification, in the polycarbonate-containing composition, of the α-olefin polymer is formed from the respective monomer(s).

[0107] The α-olefin polymer is modified with an anhydride, with an unsaturated carboxylic anhydride being used for the modification. The carboxylic anhydride is preferably selected from the group consisting of maleic anhydride, phthalic anhydride, fumaric anhydride, itaconic anhydride, and mixtures thereof. Maleic anhydride is particularly preferred.

[0108] The anhydride-modified α-olefin polymer is preferably free of styrene-butadiene rubber, most preferably rubber-free.

[0109] A preferred anhydride-modified α-olefin polymer comprises

[0110] El) 90.0-99.5 wt.%, preferably 92.0-97.5 wt.%, more preferably 94.0-97.0 wt.% of a-olefin polymer and

[0111] E2) 0.5-10.0 wt.%, more preferably 2.5-8.0 wt.%, even more preferably 3.0-6.0 wt.% anhydride.

[0112] The olefinic part E1) of the a-olefin polymer is particularly preferably characterized in that the ethylene content is 65.0-96.0 wt.%, more preferably 80.0-96.0 wt.%, most preferably 84.0-92.0 wt.%, the propylene content is 2.0-10.0 wt.%, most preferably 4.0-8.0 wt.% and the 1-octene content is 2.0-25.0 wt.%, more preferably 2.0-10.0 wt.%, most preferably 4.0-8.0 wt.%.

[0113] Most preferably, the α-olefin polymer is not based on any other monomers.

[0114] Alternatively, the olefinic part CI) of the alpha-olefin polymer is particularly preferably based on propylene and / or ethylene, most preferably at least 98 wt. Most preferably, the sole monomer unit of the alpha-olefin polymer is propylene.

[0115] The average molecular weight Mw of the anhydride-modified α-olefin polymer is preferably 300 to 40,000 g / mol, more preferably 800 to 32,000 g / mol, even more preferably 1,000 to 22,000 g / mol, and particularly preferably 3,000 to 21,000 g / mol. The molecular weight Mw is determined by gel permeation chromatography in ortho-dichlorobenzene at 150°C with polystyrene calibration. The stated value is preferably the mean of a duplicate determination.

[0116] The acid number of the anhydride-modified a-olefin polymer is preferably at least 30 mg KOH / g, more preferably 45 to 170 mg KOH / g, particularly preferably up to 100 mg KOH / g, determined according to DIN ISO 17025:2005-08 by means of potentiometric titration with alcoholic potassium hydroxide solution.

[0117] Most preferably, the anhydride-modified α-olefin polymer according to component C is based on propene, is maleic anhydride-modified and more preferably has an average molecular weight Mw, determined by gel permeation chromatography in ortho-dichlorobenzene at 150 °C with polystyrene calibration, of 1000 to 22000 g / mol, even more preferably 3000 to 21000 g / mol, and an acid number of 45 to 170 mg KOH / g, even more preferably 50 to 100 mg KOH / g, determined according to DIN ISO 17025:2005-08 by means of potentiometric titration.

[0118] The amount of anhydride-modified α-olefin polymer in the total composition is 1 wt% to 3 wt%, preferably 1.2 wt% to 2.5 wt%, more preferably 1.3 wt% to 2.3 wt%, particularly preferably 1.4 wt% to 2 wt%, in particular up to 1.6 wt%.

[0119] Other additives (component F)

[0120] The polycarbonate compositions according to the invention may contain one or more further additives other than components B, C, D and E, which are summarized here under “component F”.

[0121] Other customary additives ("further additives") are optionally present (0 wt.%), preferably up to 10 wt.%, even more preferably 0.1 wt.% to 5 wt.%, particularly preferably 0.1 wt.% to 3 wt.%, very particularly preferably 0.2 wt.% to 1.0 wt.%, wherein these percentages by weight are based on the total weight of the composition. The group of further additives does not include talc (component B) or a phosphorus-containing flame retardant according to component C. The group of further additives also does not include a fluorine-containing anti-drip agent, since this is already described as component D, nor an anhydride-modified α-olefin polymer according to component E.

[0122] Such further additives, as are typically added to polycarbonates, include, in particular, thermal stabilizers, antioxidants, mold-release agents, UV absorbers, IR absorbers, impact modifiers, antistatic agents, flame retardants other than component C, optical brighteners, light scattering agents, hydrolysis stabilizers, transesterification stabilizers, (organic) dyes, (organic / inorganic) pigments, 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 and are preferred additives according to the invention.

[0123] Further preferred additives, if any, comprise one or more further additives selected from the group consisting of thermal stabilizers, antioxidants, mold release agents, organic dyes, organic pigments, and inorganic pigments. The proportion of the further additives is particularly preferably 0 to 3 wt. Very particularly preferred further additives comprise at least one thermal stabilizer, an antioxidant, a dye, a pigment, and / or a mold release agent, most preferably a thermal stabilizer and / or a pigment.

[0124] It is understood that only such additives, and only in such quantities, may be added if they do not have a significant negative impact on the inventive effect of high CTI and good flame retardancy, and preferably also if the Vicat temperature, determined according to ISO 306:2014-3, VST Method B, is not reduced below 110°C, preferably not below 115°C. Therefore, it is particularly preferred to contain no more than 0.05 wt.% of other flame retardants in addition to the phosphorus-containing flame retardants according to component C.

[0125] The compositions according to the invention may contain other flame retardants in addition to component C, but are preferably free of those selected from the group of alkali metal, alkaline earth metal, 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.

[0126] Such flame retardants, which are preferably not present 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. Very particularly preferably, no further flame retardants are present at all.

[0127] 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 0.02 to 0.60 wt.%, in each case based on the total composition.

[0128] Particularly preferred additives are also thermal stabilizers. The amount of thermal stabilizer is preferably up to 0.20 wt.%, more preferably 0.01 to 0.10 wt.%, even more preferably 0.01 to 0.05 wt.%, particularly preferably 0.015 to 0.040 wt.%, based on the total composition.

[0129] 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, distearyl-pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite (Irgafos® 168), Diisodecylpentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,4-di-cumylphenyl)pentaerythritol diphosphite (Doverphos® S-9228), bis(2,6-di-tert-butyl-4-methylphenyljpenta-erythritol diphosphite, Diisodecyloxypentaerythritol diphosphite, bis(2,4-di-tert- butyl-6-methylphenyl)-pentaerythritol diphosphite, bis(2,4,6-tris(tert-butylphenyljpentaerythritol diphosphite, tristearylsorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, 6-Isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]- 1,3,2-dioxaphosphocin, Bis(2,4-di-tert-butyl-6-methylphenyl)methyl phosphite, bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite, 6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosphocin, 2,2',2"-Nitrilo-[triethyltris(3,3',5,5'-tetra-tert-butyl-l,r-biphenyl-2,2'-diyl)phosphite], 2-ethylhexyl(3,3',5,5'-tetra-tert-butyl-l,r-biphenyl-2,2'-diyl)phosphite, 5-butyl-5- ethyl-2-(2,4,6-tri-tert-butylphenoxy)-1,3,2-dioxaphosphiran, Bis(2,6-di-ter-butyl-4-methylphenyl)pentaerythritol diphosphite, triphenylphosphine (TPP), trialkylphenylphosphine, bisdiphenylphosphinoethane, or trinaphthylphosphine. They are used alone or in a mixture, e.g., Irganox® B900 (a mixture of Irgafos® 168 and the antioxidant Irganox® 1076 in a ratio of 4:1) or Doverphos® S-9228 with Irganox® B900 or Irganox® 1076. Triphenylphosphine (TPP), Irgafos® 168, or tris(nonylphenyl)phosphite, or mixtures thereof, are particularly preferred.

[0130] 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 preferred, preferably in amounts of 0.05-0.5 wt.%.

[0131] 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.

[0132] 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 according to the invention already have an excellent property profile without additional impact modifiers. Compositions according to the invention are therefore preferably free of impact modifiers.

[0133] The compositions according to the invention contain no other fillers besides talc, such as barium sulfate. Titanium dioxide is not considered a "filler" but rather an inorganic pigment according to component F.

[0134] If titanium dioxide is present, the compositions according to the invention preferably contain 0.1 to 2 wt.%, preferably 0.5 to 1.2 wt.% titanium dioxide. The titanium dioxide of the compositions according to the invention preferably has an average particle size D50, determined by scanning electron microscopy (STEM), of 0.1 to 5 μm, preferably 0.2 μm to 0.5 μm. However, the titanium dioxide can also have a different particle size, e.g., an average particle size D50, determined by scanning electron microscopy (STEM), of > 0.5 μm, approximately 0.65 to 1.15 μm.

[0135] The titanium dioxide preferably has a rutile structure.

[0136] The titanium dioxide used in the invention is a white pigment, Ti(IV)O2. Colored titanium dioxides contain significant amounts of elements such as Sb, Ni, and Cr in addition to titanium, resulting in a color impression other than "white." It is understood that the white pigment titanium dioxide may also contain traces of other elements as impurities. However, these amounts are so small that they do not impart any color cast to the titanium dioxide.

[0137] Suitable titanium dioxides are preferably those produced by the chloride process, hydrophobized, specially post-treated, and suitable for use in polycarbonate. In principle, uncoated titanium dioxide or a mixture of both can be used instead of coated titanium dioxide in compositions according to the invention. However, the use of coated titanium dioxide is preferred.

[0138] Possible surface modifications of titanium dioxide include inorganic and organic modifications. These include, for example, surface modifications based on aluminum or polysiloxane. An inorganic coating can contain 0.0 wt.% to 5.0 wt.% silicon dioxide and / or aluminum oxide. An organic-based modification can contain 0.0 wt.% to 3.0 wt.% of a hydrophobic wetting agent. The titanium dioxide preferably has an oil absorption number, determined according to DIN EN ISO 787-5: 1995-10, of 12 to 18 g / 100 g titanium dioxide, more preferably of 13 to 17 g / 100 g titanium dioxide, and particularly preferably of 13.5 to 15.5 g / 100 g titanium dioxide.

[0139] Particularly preferred is titanium dioxide with the standard designation R2 according to DIN EN ISO 591-1:2001-08, which is stabilized with aluminum and / or silicon compounds and has a titanium dioxide content of at least 96.0 wt.%. Such titanium dioxides are available under the brand names Kronos 2233 and Kronos 2230.

[0140] The polymer compositions according to the invention, comprising the mixed components A, B, C, D, E, optionally F, and optionally further constituents, 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 F and also other constituents 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 the introduction of additives and further constituents, with masterbatches based on the respective polymer matrix being used in particular.

[0141] 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.

[0142] 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 circuit breakers, and bus bars. The invention thus also 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, which are referred to as "elements made from a thermoplastic composition according to the invention."

[0143] The molded parts consisting of or comprising a region of a thermoplastic composition according to the invention or of layers of a thermoplastic composition according to the invention are preferably used in such EE components that are designed for an operating voltage of at least 400 V, more preferably at least 450 V. However, they can also be designed for a household operating voltage of 230 V ± 23 V in Europe, although smaller distances between the electrical conductors can now be realized.

[0144] The high tracking resistance of the polycarbonate compositions according to the invention makes it possible to achieve smaller distances between two electrical conductors of a component using the polycarbonate material than was previously possible using polycarbonate. The invention thus also relates to 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 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 is at the operating voltage U listed below: 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.,

[0145] Such small distances can only be achieved with a material that has a CTI of at least 400 V.

[0146] The invention therefore also relates to corresponding EE components in which corresponding distances are realized and which preferably have an operating voltage of at least 400 V, preferably of at least 450 V.

[0147] 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.

[0148] The selection of d2 is within the scope of the Bachmann's expertise. Preferably, d2 is at least 1.2 mm.

[0149] The invention further relates to the use of talc to increase the tracking resistance of bisphenol A homopolycarbonate. Such a targeted use also occurs, for example, when a corresponding composition is used for an insulating layer which, due to its application, requires a CTI of 400 V. For example, the composition according to the invention can be used as an insulating 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.

[0150] 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.

[0151] 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.

[0152] 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.

[0153] The invention also relates to the use of compositions according to the invention, also in the embodiments described as preferred, particularly preferred, etc., for realizing the aforementioned short distances between electrical conductors in EE components.

[0154] The features mentioned as preferred, particularly preferred, etc. for the composition naturally also apply with regard to the uses according to the invention.

[0155] Thermoplastic compositions preferred according to the invention belong to insulating material group II (400 V < CTI < 600 V), classified according to DIN EN 60664-1:2008. They have a thermal conductivity (in plane) of preferably at least 1.0 W / (mK), preferably at least 1.1 W / (mK), determined according to ASTM E 1461-13, so that good heat dissipation can also be achieved.

[0156] Various embodiments of the present invention are described below:

[0157] 1. Thermoplastic composition containing

[0158] A) at least 50% by weight of bisphenol A homopolycarbonate,

[0159] B) 32 to 37 wt% talc,

[0160] C) 4 to 10 wt.% phosphorus-containing flame retardant,

[0161] D) 0.3 to 2 wt.% fluorine-containing anti-drip agent,

[0162] E) 1 to 3 wt.% anhydride-modified a-olefin polymer, wherein the composition contains no further fillers.

[0163] 2. Thermoplastic composition according to embodiment 1, wherein the talc content of the thermoplastic composition is 34 to 36 wt.%.

[0164] 3. Thermoplastic composition according to embodiment 1 or 2, wherein the talc content of the thermoplastic composition is 34.5 to 35.5 wt.%.

[0165] 4. Thermoplastic composition according to any one of the preceding embodiments, wherein the amount of fluorine-containing anti-drip agent is 0.4 to 1.0 wt.%.

[0166] 5. Thermoplastic composition according to one of the preceding embodiments, wherein the content of aromatic polycarbonate is at least 54 wt.%.

[0167] 6. Thermoplastic composition according to one of the preceding embodiments, containing no further polycarbonate.

[0168] 7. Thermoplastic composition according to one of the preceding embodiments, wherein the phosphorus-containing flame retardant is a phosphazene or a mixture of different phosphazenes.

[0169] 8. Thermoplastic composition according to one of the preceding embodiments, wherein the anhydride-modified α-olefin polymer comprises maleic anhydride-modified propylene polymer, preferably is such a polymer.

[0170] 9. Thermoplastic composition according to any one of the preceding embodiments, wherein the composition contains 0.1 to 2 wt.% titanium dioxide.

[0171] 10. Thermoplastic composition according to one of the preceding embodiments, containing 5 to 8 wt. % phosphorus-containing flame retardant. 11. Thermoplastic composition according to one of the preceding embodiments, containing as a further component

[0172] F) one or more additives selected from the group consisting of thermal 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 or inorganic pigments, compatibilizers, additives for laser marking.

[0173] 12. Thermoplastic composition according to one of the preceding embodiments, wherein the composition is free from impact modifiers and blend partners.

[0174] 13. Thermoplastic composition according to one of the preceding embodiments, comprising

[0175] A) at least 50% by weight of bisphenol A homopolycarbonate,

[0176] B) 34 to 36 wt% talc,

[0177] C) 5 to 8 wt.% phosphorus-containing flame retardant,

[0178] D) 0.3 to 1 wt.% fluorine-containing anti-drip agent,

[0179] E) 1 to 2 wt.% anhydride-modified a-olefin polymer.

[0180] 14. Thermoplastic composition according to one of the preceding embodiments, further comprising

[0181] F) one or more additives selected from the group consisting of thermal stabilizers, antioxidants, mold release agents, UV absorbers, IR absorbers, antistatic agents, optical brighteners, light scattering agents, hydrolysis stabilizers, transesterification stabilizers, organic dyes, organic or inorganic pigments, compatibilizers, additives for laser marking.

[0182] 15. Thermoplastic composition according to one of the preceding embodiments, containing no further components than those mentioned above.

[0183] 16. Thermoplastic composition consisting of

[0184] A) at least 50% by weight of bisphenol A homopolycarbonate,

[0185] B) 34 to 36 wt% talc,

[0186] C) 5 to 8 wt.% phosphorus-containing flame retardant,

[0187] D) 0.3 to 1 wt.% fluorine-containing anti-drip agent,

[0188] E) 1 to 2 wt.% anhydride-modified a-olefin polymer.

[0189] F) 0.1 to 2 wt.% titanium dioxide,

[0190] G) one or more additives selected from the group consisting of thermal stabilizers, antioxidants, mold release agents, UV absorbers, IR absorbers, antistatic agents, optical brighteners, light scattering agents, hydrolysis stabilizers, transesterification stabilizers, organic dyes, organic or inorganic pigments, compatibilizers, and additives for laser marking. A thermoplastic composition according to any one of the preceding embodiments, wherein the phosphorus-containing flame retardant comprises a cyclic phosphazene and / or a phosphorus compound of formula (10). A thermoplastic composition according to any one of the preceding embodiments, wherein the phosphorus-containing flame retardant is a cyclic phosphazene and / or a phosphorus compound of formula (10).

[0191] (10), wherein

[0192] R 1 , R 2 , R 3 and R 4 independently of one another represent a C1- to C5-alkyl radical, in each case optionally halogenated and in each case branched or unbranched, and / or C5- to C12-cycloalkyl radical, C12- to C20-aryl radical or C7- to Cn-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 represents 0 or 1, q represents a value from 0 to 30 and

[0193] 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, each of which may be substituted or unsubstituted, bridged or unbridged. A thermoplastic composition according to embodiment 17 or 18, wherein the cyclic phosphazene is a phosphazene of formula (13)

[0194] (13), where R is the same or different and for

[0195] - an amine residue,

[0196] - an optionally halogenated, preferably fluorine-halogenated, more preferably monohalogenated, Ci- to Cs-alkyl radical, preferably methyl, ethyl, propyl or butyl radical,

[0197] - a Ci to Cs alkoxy radical, preferably a methoxy radical, ethoxy radical, propoxy radical or butoxy radical,

[0198] - a C5 to C12 cycloalkyl radical optionally substituted by alkyl, preferably C1 to C4 alkyl, and / or halogen, preferably chlorine and / or bromine,

[0199] - a Ce- to C20-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,

[0200] - 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

[0201] - a halogen radical, preferably chlorine or fluorine, or

[0202] - represents an OH radical, k represents an integer from 1 to 10, preferably a number from 1 to 8, particularly preferably 1 to 5, most particularly preferably 1.

[0203] 20. Thermoplastic composition according to embodiment 17, 18 or 19, wherein the phosphorus compound of formula (10) is a bisphenol A-based oligophosphate of formula (12) with q = 1 to 20, in particular with q = 1.0 to 1.2.

[0204] 21. Thermoplastic composition according to one of the preceding embodiments, wherein the anhydride-modified a-olefin polymer according to component C is based on propene, is maleic anhydride-modified and preferably has an average molecular weight Mw, determined by gel permeation chromatography in ortho-dichlorobenzene at 150 °C with polystyrene calibration, of 1000 to 22000 g / mol, preferably 3000 to 21000 g / mol, and an acid number of 45 to 170 mg KOH / g, preferably of 50 to 100 mg KOH / g, determined according to DIN ISO 17025:2005-08 by means of potentiometric titration.

[0205] 22. Thermoplastic composition according to embodiment 21, wherein the MVR of the aromatic bisphenol A homopolycarbonate used, determined according to ISO 1133:2012-03, at a test temperature of 300°C and 1.2 kg load, is 11 to 15 cm 3 / (10 min).

[0206] 23. A molded part consisting of or comprising a region of a thermoplastic composition according to any one of the preceding embodiments.

[0207] 24. A molded part according to embodiment 23, 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 circuit breaker, or power busbar.

[0208] 25. An EE component designed for an operating voltage of at least 375 V, comprising a molded part according to embodiment 23 or 24 or a layer of a thermoplastic composition according to any one of embodiments 1 to 22.

[0209] 26. EE component designed for an operating voltage of 400 V, comprising a molded part according to embodiment 23 or 24 or a layer of a thermoplastic composition according to one of embodiments 1 to 22.

[0210] 27. 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 22, 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): 1.8 mm to < 2.5 mm d1i(250V < U < 500V) = 3,6 mm to < 5.0 mm dliii(500 V < U < 1000 V) = 7.1 mm to < 10.0 mm.,

[0211] 28. EE component according to one of the embodiments 25 to 27, where d2 > 1.2 mm.

[0212] 29. EE component according to any one of embodiments 25 to 28, wherein the EE component is a high-voltage switch, inverter, relay, electronic connector, electrical connector, circuit breaker, part of a photovoltaic system, part of an electric motor, a charger or charging plug for electric vehicles, part of an electrical junction box, part of a smart meter housing, part of a miniature circuit breaker, part of a busbar.

[0213] 30. EE component according to one of the embodiments 25 to 30, with a degree of protection IP6K9K according to ISO 20653:2013-02.

[0214] Examples:

[0215] 1. Description of raw materials and test methods a) Raw materials

[0216] 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 F-2 250 ppm (= 0.025 wt.%, based on the total weight of component A) thermal stabilizer triphenylphosphine.

[0217] Component B1: Compacted talc with a talc content of 98 wt.%, an iron oxide content of 1.9 wt.%, an aluminum oxide content of 0.2 wt.%, loss on ignition (DIN 51081:2002 / 1000 °C) of 5.4 wt.%, pH (according to EN ISO 787-9: 1995) of 9.15, D(0.5) (sedimentation analysis) of 2.2 pm; BET surface area according to ISO 4652:2012-06 10 m 2 / g, Type: Finntalc M05SLC, Manufacturer: Elementis Minerals BV.

[0218] Component B*-2: Glass fiber from Nittobo (2-4-1, Kojimachi, Chiyoda-ku, Tokyo 102-8489, Japan), available under the trade name CSG 3PA-830. It is a flat glass fiber with a 3 mm cut length and an aspect ratio of 1.4.

[0219] Component B*-3: Burnt silicon dioxide Amosil FW 600 from Quarzwerke GmbH in Frechen, uncoated, with an average particle size D(0.5) of approximately 4 pm, D(0.98) of approximately 13 pm, a D(0.1) / D(0.9) ratio of approximately 1.5 / 10 and a specific surface area of ​​approximately 6 m 2 / g, determined according to DIN-ISO 9277:2014-01. Component Cl: Phenoxycyclophosphazene Rabitle FP110 from Fushimi Pharmaceutical, Japan, formula (13g), with a trimer content (k = 1) of approximately 68 mol%.

[0220] Component Dl: SAN-encapsulated polytetrafluoroethylene ADS5000 (approx. 50 wt.% PTFE (fluorine-containing anti-drip agent) and approx. 50 wt.% SAN) from Chemical Innovation Co., Ltd. Thailand.

[0221] Component El: Propylene-maleic anhydride polymer with a medium molecular weight (gel permeation chromatography in ortho-dichlorobenzene at 150 °C with polystyrene calibration) M w = 20700 g / mol, M n = 1460 g / mol, acid number 78 mg KOH / g, determined according to DIN ISO 17025:2005- 08 by potentiometric titration.

[0222] Component Fl: Titanium dioxide from Kronos with a D50 of 210 nm (scanning electron microscopy, ECD method; Kronos® 2230). b) Test methods

[0223] Comparative tracking index (CTI):

[0224] To determine the tracking resistance, the compositions described here were tested according to the Sehnell test method based on IEC 60112:2009. For this purpose, a 0.1% ammonium chloride test solution (395 ohm* cm resistance) was applied drop by drop 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, following the procedure described above.This process was continued until either 600 V was reached or tracking current or burning 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 tracking current or burning. This procedure determined the maximum possible voltage at which a composition could withstand 50 drops of the test solution without tracking current occurring. Finally, four more test specimens, each with 50 drops, were tested at the determined maximum voltage 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. PTI (“proof tracking index”):.

[0225] 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 in 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 of > 0.5 A occurred for 2 seconds or the specimen burned.

[0226] Flame resistance:

[0227] The flame retardancy test of the polycarbonate compositions was carried out according to Underwriter Laboratory Method UL94V at a thickness of 2mm.

[0228] 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.

[0229] VO: 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.

[0230] 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.

[0231] 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.

[0232] FOT: Flame Out Time (afterburn time), given in seconds.

[0233] Heat resistance:

[0234] 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. Thermal conductivity:

[0235] The thermal conductivity was measured on injection-molded test specimens with the dimensions 60 x 60 x 2 mm 3 Determined according to ASTM E 1461 (Nano Flash Method). "In plane" means measured in the x, y direction, "through plane" in the z direction. 2. Preparation of the specimens

[0236] The compositions were produced on a BUSS kneader. The melt temperature, speed, throughput, and torque had to be adjusted according to the procedure commonly used by those skilled in the art and tailored to the respective composition. The filler was metered using a split-feed method, with 10 wt% of the total filler being added via the main feed and the remainder via the side extruder. The test specimens, measuring 60 mm x 40 mm x 4 mm, were produced from the molding compounds using standard injection molding processes at a melt temperature of 280°C and a mold temperature of 80°C.

[0237] 3. Results

[0238] In the following tables, “ng” means “not tested” and “nb” means “failed”.

[0239] Table 1

[0240] Table 1 shows how the CTI tends to improve with increasing talc content (VI - VI-3). However, without the addition of flame retardant, flammability increases with increasing talc content (see afterburn times). Comparing examples VI-4, VI-7, and VI-1, which each contain 5 wt.% flame retardant, the trend of increasing CTI (325 V - 450 V - 500 V) with increasing talc content is also evident. No more than 10 wt.% flame retardant, and preferably no more than 8 wt.% flame retardant, should be used to prevent excessive reduction in heat resistance, which would call into question the use of polycarbonate in general. With other reinforcing fillers such as glass fiber or quartz, high tracking resistance cannot be achieved like with talc in combination with an FR package (cf. VI with VI-9 and VI-10).

Claims

Patent claims:

1. Thermoplastic composition containing A) at least 50% by weight bisphenol A homopolycarbonate, B) 32 to 37 wt.% talc, C) 4 to 10 wt% phosphorus-containing flame retardant, D) 0.3 to 2 wt% fluorinated anti-drip agent, E) 1 to 3 wt% anhydride-modified α-olefin polymer, wherein the composition contains no other fillers.

2. Thermoplastic composition according to claim 1, comprising no further polycarbonate.

3. Thermoplastic composition according to claim 1 or 2, containing 5 to 8 wt.% phosphorus-containing flame retardant.

4. Thermoplastic composition according to any of the preceding claims, wherein the anhydride-modified α-olefin polymer comprises maleic anhydride-modified propylene polymer.

5. Thermoplastic composition according to any of the preceding claims, containing 34 to 36 wt.% talc.

6. Thermoplastic composition according to one of the preceding claims, comprising as a further component F) One or more additives selected from the group consisting of thermostabilizers, antioxidants, release agents, UV absorbers, IR absorbers, impact modifiers, antistatic agents, optical brighteners, light scattering agents, hydrolysis stabilizers, transesterification stabilizers, organic dyes, organic or inorganic pigments, compatibility enhancers, laser marking additives 7. Thermoplastic composition according to any of the preceding claims, containing 0.1 to 2 wt.% titanium dioxide.

8. Thermoplastic composition according to any one of the preceding claims, comprising A) at least 50% by weight bisphenol A homopolycarbonate, B) 34 to 36 wt% talc, C) 5 to 8 wt% phosphorus-containing flame retardant, D) 0.3 to 1% by weight of fluorinated anti-drip agent, E) 1 to 2 wt% anhydride-modified α-olefin polymer. Thermoplastic composition according to claim 8, further comprising F) One or more additives selected from the group consisting of thermostabilizers, antioxidants, release agents, UV absorbers, IR absorbers, antistatic agents, optical brighteners, light scattering agents, hydrolysis stabilizers, transesterification stabilizers, organic dyes, organic or inorganic pigments, compatibility enhancers, and laser marking additives, wherein 0.1 to 2 wt.% titanium dioxide is included. A thermoplastic composition according to any one of the preceding claims, comprising no further components other than those mentioned above. A molded part consisting of, or comprising, a region of, a thermoplastic composition according to any one of the preceding claims.A molded part according to claim 11, 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 busbar, wherein the electrical component preferably has a protection rating of IP6K9K according to ISO 20653:2013-02. An electrical component comprising a molded part according to claim 11 or 12 or a layer of a thermoplastic composition according to any one of claims 1 to 10.An electrical component according to claim 13, 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 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 arcing through the air is prevented at the respective operating voltage and wherein dl is at the operating voltage U listed below: dli(0V < U < 250V): 1.8 mm to < 2.5 mm; dli(250V < U < 500V): 3.6 mm to < 5.0 mm; dliii(500V < U < 1000V): 7.1 mm to < 10.0 mm. Use of talc to increase the tracking resistance of a bisphenol A-based homopolycarbonate-based thermoplastic composition.

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