EP2635629A1

EP2635629A1 - Uv-protected polycarbonate molding materials equipped so as to be flame-retardant and having a low molecular weight decrease

Info

Publication number: EP2635629A1
Application number: EP11778593.1A
Authority: EP
Inventors: Berit Krauter; Michael Wagner
Original assignee: Bayer Intellectual Property GmbH
Current assignee: Covestro Deutschland AG
Priority date: 2010-11-05
Filing date: 2011-11-03
Publication date: 2013-09-11
Also published as: CN103339178A; US20130221294A1; WO2012059531A1

Abstract

The invention relates to flameproofed UV-resistant polycarbonate molding materials having a good melt stability and a high fraction of free, reactive UV absorbers, wherein the polycarbonate compositions contain A) at least one polycarbonate having an average molecular weight M̅ w from 18,000 to 40,000, B) at least one organic flameproofing agent comprising diphenyl sulfone, alkali or alkaline-earth diphenyl sulfone sulfonate, and alkali or alkaline-earth diphenyl sulfone disulfonate, and C) one or more reactive UV absorbers, and wherein B) comprises diphenyl sulfone in a fraction from 1.10 wt % to 2.50 wt %, relative to the total mass of the component B).

Description

Flame retardant, U V-protected polycarbonate molding compounds with low molecular weight degradation

The present invention relates to flame-retardant UV-stable polycarbonate molding compositions having a good melt stability and a high proportion of free, reactive UV absorbers. Due to the excellent properties of plastics such as e.g. Transparency, toughness and low density paired with thermoplastic ductility, which ensures high design freedom, are increasingly replacing plastics with metal as a material from various applications. This happens especially where weight reduction comes to the fore. These materials are mainly used in aircraft construction, but also in rail transport or automotive engineering. In addition, plastics are also used in IT and electrical engineering and electronics, where they are used e.g. be used as a carrier of live parts or for the production of television and monitor housings.

For the applications mentioned above, it is often necessary for the plastics used, in addition to good mechanical properties, to have an increased flame retardance and good resistance to UV radiation. In order to achieve this, suitable additives, such as flame retardants and UV stabilizers, must be added to the plastics that are generally combustible.

However, the addition of these additives not only brings the desired benefits. Thus, it is known to those skilled in the art that in the equipment of polycarbonates with UV absorbers they can be incorporated into the polymer chain. This is especially true in the case of reactive UV absorbers which have free functionalities which can be incorporated into the polycarbonate chain, such as e.g. free hydroxyl groups.

The incorporation of the UV absorber leads to a reduction in the molecular weight of the polymer, which can be determined by the melt stability, which increases with decreasing molecular weight and can lead to problems in processing due to a change in the flow properties.

Lower molecular weight polycarbonates also tend to have inferior mechanical properties. Short-chain polycarbonates are more prone to burning droplets in the UL94V test than long-chain ones. Thus, the molecular weight degradation caused by the esterification of the UV absorber also gives a negative influence on the flame retardancy. This described problem also exists for polycarbonate compositions which are flame-retardant with the aid of alkali or alkaline-earth salts, since here the poor dripping behavior is primarily responsible for a negative evaluation in the flame retardancy test.

JP 2003-176404 describes polycarbonate compositions which can be antistatically finished by adding KSS salt in combination with benzenesulphonic acid phosphonium salts.

Furthermore, UV stabilizers may be included in the compositions. However, JP 2003-176404 gives no indication of the melt stability of the compounds and their dependence on the additives used, as well as improved flame retardance.

JP 2007-352749 describes flame retardant polycarbonate compositions containing perfluoroalkanesulfonic acid salts, halogenated triaryl phosphates, and potassium diphenylsulfone sulfonate, as well as other additives. In addition, these compounds can be equipped with a UV stabilizer. However, JP 2007-352749 gives no indication of UV-protected compositions according to the present invention having improved melt stability and good flame retardancy.

The object of the present invention was therefore to provide flameproofed polycarbonate molding compositions in which a flame retardant is present in the presence of a UV absorber and only a small degradation of the polymer chain takes place, so that the melt stability of the molding compositions is improved. In particular, it was an object of the present invention to provide such molding compositions having a ratio of IMVR / MVR (Time Dependent Melt Flow Rate / Melt Flow Rate) of less than or equal to 1:15 and a ratio of free UV absorber incorporated into the polymer chain greater than or equal to 1, 5 have.

The object described above is surprisingly achieved by a composition comprising at least one polycarbonate, at least one alkali metal or alkaline earth metal salt

Flame retardant and at least one UV absorber, wherein the alkali metal or alkaline earth metal salt is a mixture of diphenylsulfone, potassium diphenylsulfone sulfonate and potassium diphenylsulfon disulfonate and the proportion of potassium diphenylsulfone sulfonate based on 100 wt.% Of the mixture 80 maximum % By weight. The compositions of the invention have a significantly reduced degradation of the

Polymer chain at a ratio of IMVR / MVR less than or equal to 1, 15 and a ratio of free to built-in UV absorber greater than or equal to 1.5. In a preferred embodiment, the alkali metal or alkaline earth metal salt contains a) diphenylsulfone in a proportion of from 1.10% by weight to 2.50% by weight, more preferably from 1.20% by weight to 2.30% by weight. , and more preferably from 1.30% to 2, 10%, by weight, b) of alkali or alkaline earth diphenylsulfone sulfonate in a proportion of from 70.00% to 80.00% by weight preferably 72.00 wt .-% to 79.00 wt .-% and particularly preferably 74.00 wt .-% to 78.00 wt .-%, and, c) alkali metal or alkaline earth metal diphenylsulfone disulfonate in one portion from 16.50% by weight to 28.90% by weight, more preferably from 17.70% by weight to 26.80% by weight and particularly preferably from 19.90% by weight to 24.70% by weight %, whereby the individual sums of the weight% information add up to 100 each.

Preferably, the cation of the alkali or alkaline earth salt is potassium.

In a further preferred embodiment, the proportion of potassium diphenylsulfone sulfonate in a range of 74.00 wt .-% to 78.00 wt .-% and the proportion of potassium diphenylsulfon disulfonate of 21.00 wt .-% to 24.00 wt .-%, with particular preference the proportion of diphenylsulfone from 1.30 wt .-% to 2.50 wt .-% is.

Corresponding compositions can be obtained either by recrystallization or by mixing the pure components.

Regardless of the aforementioned constituents, the alkali or alkaline earth metal salt may additionally contain further by-products and impurities, these not exceeding a proportion of 0.1%.

Optionally, the compositions of the invention may contain other flame retardants and additives, but preferably only the above flame retardants and additives are present and the molding compositions are preferably free of flame retardants and additives selected from the group of benzenesulfonic acid-phosphonium salts, halogenated triaryl phosphates and Perfluoralkansulfonsäuresalzen and mixtures thereof.

Optional further flame retardants for the purposes of the present invention are in particular sodium or potassium 2,5-dichlorobenzenesulfate, sodium or potassium 2,4,5-trichlorobenzenesulfate, sodium or potassium methyl phosphonate, sodium or potassium (2-phenyl -ethylene) phosphonate, sodium or potassium pentachlorobenzoate, sodium or potassium 2,4,6-trichlorobenzoate, sodium or potassium 2,4-dichlorobenzoate, lithium phenylphosphonate, sodium or potassium 2-formylbenzoate. zolsulfonate, sodium or potassium (N-benzenesulfonyl) benzenesulfonamide. Trisodium or tri-lithium hexafluoroaluminate, disodium or dipotassium hexafluorotitanate, disodium or dipotassium hexafluorosilicate, disodium or dipotassium hexafluorozirconate, sodium or potassium pyrophosphate, sodium or potassium metaphosphate, sodium or potassium tetrafluoroborate , Sodium or potassium hexafluorophosphate, sodium or potassium or lithium phosphate, N- (p-tolylsulfonyl)

) -p-toluenesulfimide potassium salt, N- (N'-benzylaminocarbonyl) sulfanylimide potassium salt.

Preference is additionally given to using sodium or potassium 2,4,6-trichlorobenzoate and N- (p-tolylsulfonyl) -p-toluenesulfimide potassium salt and N- (N'-benzylaminocabonyl) sulfanylimide potassium salt. The alkali metal or alkaline earth metal salts are used in the amounts of

0.001 wt% to 1.000 wt%, preferably 0.001 wt% to 0.800 wt%, more preferably 0.01 wt% to 0.60 wt%, and still more preferably 0.10 Wt .-% to 0.30 wt .-%, and particularly preferably 0, 12 wt .-% to 0.20 wt .-%, while s based on the total composition used in the molding compositions. The molding compositions of the present invention further comprise at least one reactive UV

Absorber, wherein reactive means that the UV absorber has a functionality by which it can be incorporated into the polymer chain of the polycarbonate, in particular a hydroxyl group.

UV absorbers can be used here alone or as a mixture of two or more UV absorbers, preferably of different classes (according to formulas I-III). The UV absorbers are used in the scope of the present invention in amounts of 0.0001% by weight to 0.5000% by weight, preferably 0.0001% by weight to 0.3000% by weight, more preferably 0.001% by weight. to 0.250 wt .-%, and particularly preferably 0.05 wt .-% to 0, 15 wt .-%, each based on the total composition used.

Suitable UV absorbers in the context of the present invention are compounds of the formula (I), it also being possible to use mixtures of differently substituted compounds,

wherein

R 1 and R 2 are the same or different and are H, halogen, C 1 to C 10 alkyl, C 5 to C 10 cycloalkyl, C 7 to C 13 aralkyl

C6 to C14 aryl, -OR5 or - (CO) -O-R5, with

R5 is H or Cl - to C4-alkyl,

R3 and R4 are the same or different and are H, C1 to C4 alkyl, C5 to C6 cycloalkyl, benzyl or C6 to C14 aryl, m is 1, 2 or 3 and n is 1, 2, 3 or 4 is.

Further suitable UV absorbers are compounds of the formula (II) and also mixtures which are substituted in different ways,

wherein

R and X are identical or different and are H or alkyl or alkylaryl,

Further suitable UV absorbers are compounds of the formula (III) and also mixtures which are substituted in different ways,

wherein R 1 and R 2 are identical or different and are H, halogen, C 1 - to C 10 -alkyl, C 5 - to C 10 -cycloalkyl, C 7 - to C 13 -aralkyl,

C6 to C14 aryl, -OR5 or - (CO) -O-R5, with

R5 is H or Cl - to C4-alkyl, m is 1, 2 or 3 and n is 1, 2, 3 or 4,

Bridge equal

O O

- {CHR ^W ) - C-O- (Y-O) - C ~ {CHR ¹ ) _p , where p is 0, 1, 2 or 3, q is an integer from 1 to 10,

Y is -CH 2 -CH 2 -, - (CH 2) 3, - (CH 2) 4, - (CH 2) 5, - (CH 2) 6, or CH (CH 3) -CH 2 -and and

R 10 and R 11 are identical or different and denote H, C 1 - to C 4 -alkyl, C 5 - to C 6 -cycloalkyl, benzyl or C 6 - to C 14 -aryl. Among the compounds of the formulas (I), (II) and (III), those are preferred

R 1 = H, R 2 = Cl - to C 8 -alkyl, especially R 2 = isooctyl, R 3 = H, R 4 = H, m = 1, n = 4, R = H or 2-butyl or tert-butyl or -C ( CH3) 2-phenyl, X = Cl - to C8-alkyl or -C (CH3) 2-phenyl or isooctyl, p = 0, 1, 2 or 3, q = 1 to 8, Y = - (CH2) 6- or - (CH 2) 2, RIO = H and R 11 = H. The compounds of formula (I), (II) and (III) to be used according to the invention are commercially available. They can be prepared by known methods. Compounds of formula (I) such as 2,2-methylene-bis- (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benztriazol-2-yl) -phenol) are commercially available under the designation Tinuvin® 360 or Adeka Stab® LA 3 1 distributed. Compounds of formula (II) are 2- (2-hydroxy-5-tert-octylphenyl) -2H-benzotriazole (Tinuvin® 329), 2- (2H-benzotriazol-2-yl) -4- (1,1-dimethylethyl ) -6- (2-methylpropyl) phenol (Tinuvin® 350) or 2- [2'-hydroxy-3,5-di (1,1-dimethylbenzyl) phenyl] -2H-benzotriazole (Tinuvin® 234). The Tinuvines are available from BASF AG, Ludwigshafen, Germany (formerly available from Ciba Speziitätenchemie, Lampertheim, Germany).

In addition, the molding compositions may be provided with further UVA stabilizers, such as those based on cyanoacrylate or triazine. In the context of the present invention, the use of benzotriazole type UV absorbers is particularly preferred. From this group, in turn, the use of 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (CAS No. 3147-75-9) is again very particularly preferred.

Suitable polycarbonates for the production of the plastic composition according to the invention are all known polycarbonates. These are homopolycarbonates, copolycarbonates and thermoplastic polyestercarbonates.

The suitable polycarbonates preferably have weight average molecular weights M _{w from} 18,000 to 40,000, preferably from 22,000 to 31,000 and in particular 26,000 to 28,000, determined by measuring the relative solution viscosity in dichloromethane (against polycarbonate standard) at a concentration of 5 g / 1 and a temperature of 25 ° C with a Ubbelohde viscometer. The preparation of the polycarbonates is preferably carried out by the interfacial process or the melt transesterification process, which are described in various ways in the literature. For the interfacial process, see, for example, H. Schnell, Chemistry and Physics of Polycarbonates, Polymer Reviews, Vol. 9, Interscience Publishers, New York 1964, p. 33 et seq., Polymer Reviews, Vol. 10, "Condensation Polymers by Interfacial and Solution Methods". , Paul W. Morgan, Interscience Publishers, New York 1965, Chapter VIII, p. 325, to Dres. U. Grigo, K. Kircher and P. R-Müller "Polycarbonates" in Becker / Braun, Kunststoff-Handbuch, Vol 3/1, polycarbonates, polyacetals, polyesters, cellulose esters, Carl Hanser Verlag Munich, Vienna 1992, p 1 18-145 and EP-A 0 517 044 referenced.

The melt transesterification process is described, for example, in the Encyclopedia of Polymer Science, Vol. 10 (1969), Chemistry and Physics of Polycarbonates, Polymer Reviews, H. Schnell, Vol.

John Wiley and Sons, Inc. (1964) as well as in the patents DE-B 10 31 512 and US-B 6 228 973.

The polycarbonates are obtained from reactions of bisphenol compound with carbonic acid compounds, in particular phosgene, or in the melt transesterification process, diphenyl carbonate or dimethyl carbonate. Homopolycarbonates are based on this

Bisphenol A and copolycarbonates based on the monomers bisphenol A and l, l-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane are particularly preferred. Further bisphenol compounds, which can be used for the polycarbonate synthesis, are disclosed inter alia in WO-A 2008037364, EP-A 1 582 549, WO-A 2002026862, WO-A 2005113639

The polycarbonates may be linear or branched. Mixtures of branched and unbranched polycarbonates can also be used. Suitable branching agents for polycarbonates are known from the literature and described for example in the patents US-B 4 185 009, DE-A 25 00 092, DE-A 42 40 313, DE-A 19 943 642, US-B 5 367 044 and US Pat in literature cited herein. In addition, the polycarbonates used can also be intrinsically branched, in which case no branching agent is added during the polycarbonate production. An example of intrinsic branches are so-called frieze structures, as disclosed for melt polycarbonates in EP-A 1 506 249.

The polycarbonates and copolycarbonates according to the invention may also contain other aromatic polycarbonates and / or other plastics such as aromatic polyester carbonates, aromatic polyesters such as polybutylene terephthalate or polyethylene terephthalate, polyamides, polyimides, polyesteramides, polyacrylates and polymethacrylates such as, for example, polyalkyl (meth) acrylates and in particular polymethyl methacrylate, polyacetals, Polyurethanes, polyolefins, halogenated

Polymers, polysulfones, polyethersulfones, polyether ketones, polysiloxanes, polybenzimidazoles, urea-formaldehyde resins, melamine-formaldehyde resins, phenol-formaldehyde resins, alkyd resins, epoxy resins, polystyrenes, copolymers of styrene or of alpha-methylstyrene with dienes or acrylic derivatives, graft polymers based on Acrylonitrile / butadiene / styrene or based on acrylate rubber graft copolymers (see, for example, the graft polymers described in EP-A 640 655) or silicone rubbers are admixed in a known manner, for example by compounding.

Polycarbonates, copolycarbonates and compounding blends described above are present in the present compositions at a level of from 99.9989% to 68.5% by weight, preferably at a level of from 99.9979% to 78, 9 wt .-%, more preferably in one

Content of 99.889 wt .-% to 89.45 wt.%, Particularly preferably in a proportion of 99.82 wt .-% to 93 wt .-%, included.

The polycarbonates according to the invention and optionally further plastics contained can also be added in the usual amounts of the usual additives for these thermoplastics such as fillers, heat stabilizers, antistatic agents and pigments; if appropriate, the demolding behavior and / or the flow behavior can be improved by adding external mold release agents and / or flow agents (for example alkyl- and aryl phosphites, phosphates, phosphanes, low molecular weight carboxylic esters, halogen compounds, salts, chalk, quartz powder, glass - and Carbon fibers, pigments and their combination). The molding compositions according to the invention preferably contain no antistatic agents.

Such compounds are z. In WO 99/55772 A1, pages 15-25, EP 1 308 084 and in the corresponding chapters of the "Plastics Additives Handbook", ed. Hans Zweifel, 5 ^th Edition 2000, Hanser Publishers, Munich.

The aforementioned additives are present in the compositions of the present invention in amounts of from 0% to 30% by weight, preferably from 0.001% to 20,000%, more preferably from 0.01% to 10.00 Wt .-%, contained.

Examples Preparation of the compositions:

The preparation of a composition containing polycarbonate and the additives mentioned below is carried out by conventional incorporation methods and can be, for example, by mixing solutions of the additives and solution of polycarbonate in suitable solvents such as dichloromethane, haloalkanes, haloaromatics, chlorobenzene and xylenes. The solution mixtures are preferably worked up in a known manner by evaporation of the solvent and subsequent extrusion, for example, compounded.

In addition, the composition can be mixed in conventional mixing devices such as screw extruders (for example twin-screw extruder, ZSK), kneaders, Brabender or Banbury mills and then extruded. After extrusion, the extrudate can be cooled and comminuted. It is also possible to premix individual components and then to add the remaining starting materials individually and / or likewise mixed.

The compositions according to the invention can be worked up in a known manner and processed to give any shaped bodies, for example by extrusion, injection molding or extrusion blow molding. The determination of the melt index (MVR, IMVR) is carried out according to ISO 1133 (300 ° C, 1.2 kg, 6 min

(MVR) or 19 min (IMVR)).

The content of free Tinuvin was determined by UV / Vis spectroscopy.

Polycarbonate was dissolved in dichloromethane (0.5 g PC in 100 ml dichloromethane) and the UV-Baconum was measured in a cuvette with a thickness of D = 2 mm. Tinuvin 329 is detected at the two wavelengths 300 nm for the total amount used and at 340 nm for the free portion of the tinuvin. The incorporated amount of TIN 329 was determined from the difference of the products from the UV intensities at 300nm multiplied by the factor 2, 16 and at 340nm multiplied by the factor 1.96. The factors were determined by calibration.

The determination of the proportion of diphenylsulfone, diphenylsulfone monosulfonate and diphenylsulfone disulfonate in the mixture was carried out by HPLC with:

Column: ODS Hypersil 3μ 125 x 4.6 mm

Plasticizer: A) water with 0.1% acetic acid and 0.1% tetra-n-butylammonium bromide, B) acetonitrile

Gradient: 0 min 80% A, 15 min 50% A, 17 min 80% A. Flow 1 ml / min.

Detection: UV 240 nm

The quantification was carried out according to the method of the external standard with solutions having known contents of diphenylsulfone, diphenylsulfone monosulfonate and diphenylsulfone disulfonate.

Preparation of the compositions for the examples below:

Substances used to prepare the compositions

AI) Makroion® 2408 powder is a commercially available linear polycarbonate based on bisphenol A from Bayer MaterialScience AG. Makroion® 2408 contains no UV absorber. The melt volume flow rate (MVR) according to ISO 1133 is 19 cm7 (10 min) at 300 ° C and

1.2 kg load.

A2) Tinuvin 329 is one of 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol and Tinuvin® 329 (CAS No. 3147-75-9) BASF AG, Ludwigshafen, Germany (formerly available from Ciba Speziitätenchemie, Lampertheim, Germany commercially available, A3) Is known under the name KSS, and a mixture of diphenylsulfone, potassium diphenylsulfone sulfonate and potassium diphenylsulfone-disulfonate and example in Sloss Industries Cooperation (Birmingham, Alabama USA), Rutherford (UK), Aarti (India), Brenntag, Metropolitan commercially available. KSS salts with different proportions of diphenylsulfone, potassium diphenylsulfone sulfonate and potassium diphenylsulfone disulfonate were obtained by recrystallization and the proportions of the individual components were determined by HPLC. B) in the table below describes the proportions of diphenylsulfone, potassium diphenylsulfone sulfonate and potassium diphenylsulfone disulfonate in the KSS salt used in each case.

C) gives the ratio of free UV absorber to built-in UV absorber as well as the ratio of IMVR to MVR. To prepare the examples, powder mixtures of macroion 2408 and the substances

A2) and A3) were prepared in the amounts shown in Table 1 and determined MVR and IMVR for the powder mixtures. The content of free Tinuvin was determined as described above on the MVR strands.

Table 1: Examples

A: Composition of compound in% by weight, B Composition of KSS salt used in% by weight based on A3, C Properties of the compound

As can be seen from Examples 1 and 2, the novel compositions or molding compositions have a significantly lower ratio of IMVR to MVR, which means a higher stability of the polycarbonate molding compositions. In addition, a significantly higher proportion of free UV absorber can be found in the compositions according to the invention, resulting in improved UV protection.

Claims

claims

1. Containing polycarbonate compositions

A) at least one polycarbonate having an average molecular weight M _{w of from} 18,000 to 40,000,

B) at least one alkali metal or alkaline earth metal salt of an organic flame retardant consisting of diphenylsulfone, alkali metal or alkaline earth metal diphenylsulfone sulfonate and alkali metal or alkaline earth metal diphenylsulfone disulfonate, and

C) one or more reactive UV absorbers, characterized in that B) diphenyl sulfone in a proportion of 1, 10 wt .-% to 2.50 wt .-%, based on the total mass of component B), having.

2. polycarbonate compositions according to claim 1, characterized in that B) alkali metal or alkaline earth diphenylsulfonsulfonat in a proportion of 70.00 wt .-% to 80.00 wt .-%, based on the total mass of component B).

3. polycarbonate compositions according to claim 1 or 2, characterized in that B) alkali metal or alkaline earth diphenylsulfondisulfonat in a proportion of 16.50 wt .-% to 28.90% by weight, based on the total mass of component B), having.

4. polycarbonate compositions according to claim 1 or 2, characterized in that the proportion of diphenylsulfone from 1.30 wt .-% to 2.50 wt .-%, the proportion of alkali metal or alkaline earth diphenylsulfon-sulfonate in a range of 74, 00 wt. To 78.00 wt .-% and the proportion of alkali or alkaline earth diphenylsulfone disulfonate of 21.00 wt .-% to 24.00 wt -.%, Based on the total amount of component B)

5. polycarbonate compositions according to claim 1, characterized in that the alkali metal or alkaline earth metal of the flame retardant is potassium.

6. Polycarbonate compositions according to claim 1, characterized in that the ratio of free UV absorber to built-in UV absorber is greater than 2.5, preferably equal to or greater than 3.0.

7. polycarbonate compositions according to claim 1, characterized in that the UV absorber C) is selected from the group of benzotriazoles, triazines or cyanoacrylates.

8. polycarbonate composition according to claim 1, characterized in that it is in the UV absorber C) is a benzotriazole, preferably 2- (2H-benzotriazol-2-yl) -4- (l, 1,3,3-tetramethylbutyl ) -phenol, acts.

9. Polymer composition according to claim 1, characterized in that the ratio of IMVR to MVR is less than or equal to 1.15.

10. flame retardants based on diphenylsulfone diphenylsulfone, alkali metal or alkaline earth diphenylsulfonsulfonat and alkali or alkaline earth diphenylsulfone disulfonate, characterized in that diphenyl sulfone in a proportion of 1, 10 wt .-% to 2.50 wt .-%, based is present on the total mass of the flame retardant.

11. Flame retardant according to claim 10, characterized in that alkali metal or alkaline earth diphenylsulfonsulfonat in a proportion of 70.00 wt .-% to 80.00 wt .-%, based on the total mass of the flame retardant, is present.

12. Flame retardant according to claim 10, characterized in that the alkali metal or Erdalkali- diphenylsulfondisulfonat in a proportion of 21.00 wt .-% to 24.00 wt .-%, based on the total mass of the flame retardant present.

13. Flame retardant according to claim 10, characterized in that the proportion of diphenyl sulfone from 1.30 wt .-% to 2.50 wt .-%, the proportion of alkali metal or alkaline earth metal diphenylsulfon- sulfonate in a range of 74.00 wt to 78.00 wt .-% and the proportion of alkali metal or alkaline earth metal diphenylsulfone disulfonate of 21.00 wt .-% to 24.00 wt .-%, based on the total mass of the flame retardant, is present.

14. Use of alkali or alkaline earth salts for the preparation of flame-retardant polycarbonate compositions according to one or more of the preceding claims, characterized in that the proportion of diphenyl sulfone 1.30 wt .-% to 2.50 wt .-%, the proportion of alkali metal or alkaline earth diphenylsulfone sulfonate in a range of 74.00 wt. To 78.00 wt .-% and the proportion of alkali or alkaline earth diphenylsulfone disulfonate of 21.00 wt .-% to

24.00 wt .-%, based on the total mass of the flame retardant.

15 molded bodies containing polycarbonate compositions according to any one of claims 1 to 9.