Polycarbonate composition

Abstract

The present invention relates to a polycarbonate composition comprising the following components, relative to the total weight of the composition， A) 90-99 wt.% of an aromatic polycarbonate, B) 0.2-0.8 wt.% of a sulfonated polyester, C) 0.5-3.5 wt.% of a core-shell impact modifier selected from the group consisting of methyl methacrylate-butadiene-styrene (MBS), acrylonitrile-butadiene-styrene (ABS), silicone-acrylate rubber based impact modifiers and combinations thereof, and D) 0.2-0.5 wt.% of polytetrafluoroethylene. The present invention also relates to a shaped article made from the composition. The polycarbonate composition according to the present invention has a good combination of flame retardancy and impact strength.

Description

[0001] POLYCARBONATE COMPOSITION

[0002] TECHNICAL FIELD

[0003] The present invention relates to a polycarbonate (PC) composition with good flame retardancy and impact strength. In particular, the present invention relates to a polycarbonate composition and a shaped article made from the same.

[0004] BACKGROUND ART

[0005] It is known in the art that polycarbonate compositions can achieve good flame-retardant performance by loading enough amount of traditionally flame-retardant agents such as potassium perfluorobutane sulfonate. For example, the usage of any of a variety of salts, notably perfluoroalkane sulfonate salts, of alkali metal or alkaline earth metal as a flame retardant for polycarbonate has been disclosed in U.S. Pat. Nos. 3,775, 367; 46060,469,833; 4,626,563; 4,626,563; and 4,649,168.

[0006] In most flame retardant PC compositions, potassium perfluorobutane sulfonate has been proved to be the most efficient flame retardant agent so far. Very small amount (usually less than 0.2 wt% is used) of potassium perfluorobutane sulfonate is needed for PC compositions to achieve a flame-retardency level of UL94 VO at a thickness of 1.5 mm. It has been shown that potassium perfluorobutane sulfonate does not affect the mechanical and thermal properties of polycarbonate compositions. With such a small loading of potassium perfluorobutane sulfonate in polycarbonate compositions, optical properties, colorability, and surface quality will also not be affected. However, since potassium perfluorobutane sulfonate contains fluorine, some potential environmental contamination might occur during manufacturing and following applications of polycarbonate compositions containing potassium perfluorobutane sulfonate. Considering that, potassium perfluorobutane sulfonate has been banned according to the Blue Angel and is also on the list of SVHC (Substances of Very High Concern) of REACH. In the US, several states are drafting the bills to restrict the use of PF AS that includes potassium perfluorobutane sulfonate.

[0007] In addition, since 2020 it is required by REACH (registration, evaluation, authorization and restriction of chemicals) regulation in the European Union that the loading of potassium perfluorobutane sulfonate in polymer blends should be less than 1000 ppm by weight.

[0008] Therefore, we can see that there are higher requirements than before on the plastic housing materials for electronics& electrical (EE) applications targeting high flame retardant level and good toughness that is able to meet strict regulations and pass functional tests. In most cases, a flame retardancy level of UL94 V0 at a thickness of 1.5 mm needs to be achieved and some impact tests such as ball drop test has to be passed. Therefore, there is a need for polycarbonate compositions which can be used to prepare articles with a good combination of flame retardancy and impact strength.

[0009] SUMMARY OF THE INVENTION

[0010] One object of the present application is thus to provide a polycarbonate composition which can be used to prepare articles having a good combination of flame retardancy and impact strength.

[0011] Another object of the present application is to provide an article which has a good combination of flame retardancy and impact strength.

[0012] In a first aspect, the present invention provides a polycarbonate composition comprising the following components, relative to the total weight of the composition:

[0013] A) 90-99 wt.% of at least one aromatic polycarbonate,

[0014] B) 0.2-0.8 wt.% of at least one sulfonated polyester,

[0015] C) 0.5-3.5 wt.% of at least one core-shell impact modifier selected from the group consisting of methyl methacrylate-butadiene-styrene (MBS), acrylonitrile-butadiene-styrene (ABS), silicone-acrylate rubber based impact modifiers and combinations thereof, and

[0016] D) 0.2-0.5 wt.% of polytetrafluoroethylene.

[0017] The inventors have unexpectedly discovered that the composition according to the present invention, comprising a small amount of sulfonated polyester in combination with of a core-shell impact modifier selected from the group consisting of methyl methacrylate-butadiene-styrene (MBS), acrylonitrile- butadiene-styrene (ABS), silicone-acrylate rubber based impact modifiers and combinations thereof, can be used to prepare articles having a good combination of flame retardancy and impact strength. For example, the articles prepared with the composition according to the present invention have an

[0018] 2 2 impact strength more than 54 kJ / m at 0 °C and more than 58 kJ / m at 23 °C as determined according to ISO 180 / A:2000. Meanwhile, the articles prepared with the composition according to the present invention have a flame retardancy of V0 at a thickness of 1.5 mm as measured according to UL94: 2015.

[0019] In a second aspect, the present invention provides a shaped article made from a polycarbonate composition according to the first aspect of the present invention.

[0020] In a third aspect, the present invention provides a process for preparing the shaped article mentioned above, comprising injection moulding, extrusion moulding, blow moulding or thermoforming the polycarbonate composition according to the first aspect of the present invention. Other subjects and characteristics, aspects and advantages of the present invention will emerge even more clearly on reading the description and the examples that follow.

[0021] DETAILED DESCRIPTION OF THE INVENTION

[0022] In that which follows and unless otherwise indicated, the limits of a range of values are included within this range, in particular in the expressions "between ... and ..." and "from ... to ...".

[0023] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. When the definition of a term in the present description conflicts with the meaning as commonly understood by those skilled in the art the present invention belongs to, the definition described herein shall apply.

[0024] Throughout the instant application, the term “comprising” is to be interpreted as encompassing all specifically mentioned features as well optional, additional, unspecified ones.

[0025] Unless otherwise specified, all numerical values expressing amount of ingredients and the like which are used in the description and claims are to be understood as being modified by the term “about”.

[0026] Component A

[0027] The polycarbonate composition according to the present invention comprises at least one aromatic polycarbonate.

[0028] According to the invention, “aromatic polycarbonates” or else just “polycarbonates” is to be understood as meaning both homopolycarbonates and copolycarbonates, in particular aromatic ones. These polycarbonates may be linear or branched in known fashion. According to the invention, mixtures of polycarbonates may also be used.

[0029] Aromatic polycarbonates selected in accordance with the invention preferably have weight-average molecular weights Mwof 15 000 to 40 000 g / mol, more preferably of 16 000 to 34 000 g / mol, even more preferably of 17 000 to 33 000 g / mol, most preferably of 19 000 to 32 000 g / mol. The values for Mwhere are determined by a gel permeation chromatography, calibrated against bisphenol A polycarbonate standards using dichloromethane as eluent, calibration with linear polycarbonates (made of bisphenol A and phosgene) of known molar mass distribution from PSS Polymer Standards Service GmbH, Germany; calibration according to method 2301-0257502-09D (2009 Edition in German) from Currenta GmbH & Co. OHG, Leverkusen. The eluent is dichloromethane. Column combination of crosslinked styrene-divinylbenzene resins. Diameter of analytical columns: 7.5 mm; length: 300 mm. Particle sizes of column material: 3 gm to 20 |im. Concentration of solutions: 0.2% by weight. Flow rate: 1.0 ml / min, temperature of solutions: 30°C. Detection using a refractive index (RI) detector.

[0030] The polycarbonates are preferably produced by the interfacial process or the melt transesterification process, which have been described many times in the literature.

[0031] With regard to the interfacial process reference is made for example to H. Schnell, “Chemistry and Physics of Polycarbonates”, Polymer Reviews, Vol. 9, Interscience Publishers, New York 1964 p. 33 et seq., to Polymer Reviews, Vol. 10, “Condensation Polymers by Interfacial and Solution Methods”, Paul W. Morgan, Interscience Publishers, New York 1965, Chapt. VIII, p. 325, to Dres. U. Grigo, K. Kircher and P. R- Muller “Polycarbonate” in Becker / Braun, Kunststoff-Handbuch, Volume 3 / 1, Polycarbonate, Poly acetale, Polyester, Celluloseester, Carl Hanser Verlag Munich, Vienna 1992, pp. 118-145 and also to EP 0 517 044 Al.

[0032] 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. 9, John Wiley and Sons, Inc. (1964), and in patent specifications DE 10 31 512 A and US 6,228,973 Bl.

[0033] Particulars pertaining to the production of polycarbonates are disclosed in many patent documents spanning approximately the last 40 years. Reference may be made here by way of example to Schnell, “Chemistry and Physics of Polycarbonates”, Polymer Reviews, Volume 9, Interscience Publishers, New York, London, Sydney 1964, to D. Freitag, U. Grigo, P.R. Muller, H. Nouvertne, BAYER AG, “Polycarbonates” in Encyclopedia of Polymer Science and Engineering, Volume 11, Second Edition, 1988, pages 648-718, and finally to U. Grigo, K. Kirchner and P.R. Muller “Polycarbonate” in Becker / Braun, Kunststoff-Handbuch, Volume 3 / 1, Polycarbonate, Polyacetale, Polyester, Celluloseester, Carl Hanser Verlag Munich, Vienna 1992, pages 117-299.

[0034] The production of aromatic polycarbonates is effected for example by reaction of dihydroxyaryl compounds with carbonic halides, preferably phosgene, and / or with aromatic dicarboxyl dihalides, preferably benzenedicarboxyl dihalides, by the interfacial process, optionally using chain terminators and optionally using trifunctional or more than trifunctional branching agents, production of the polyester carbonates being achieved by replacing a portion of the carbonic acid derivatives with aromatic dicarboxylic acids or derivatives of the dicarboxylic acids, specifically with aromatic dicarboxylic ester structural units according to the carbonate structural units to be replaced in the aromatic polycarbonates. Preparation via a melt polymerization process by reaction of dihydroxyaryl compounds with, for example, diphenyl carbonate is likewise possible.

[0035] Dihydroxyaryl compounds suitable for the production of polycarbonates are for example hydroquinone, resorcinol, dihydroxydiphenyls, bis(hydroxyphenyl)alkanes, bis(hydroxyphenyl)cycloalkanes, bis(hydroxyphenyl) sulfides, bis(hydroxyphenyl) ethers, bis(hydroxyphenyl) ketones, bis(hydroxyphenyl) sulfones, bis(hydroxyphenyl) sulfoxides, a,a’- bis(hydroxyphenyl)diisopropylbenzenes, phthalimidines derived from derivatives of isatin or phenolphthalein and the ring-alkylated, ring-ary lated and ring-halogenated compounds thereof.

[0036] Preferred dihydroxyaryl compounds are 4,4 ’-dihydroxy diphenyl, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 2,4-bis(4-hydroxyphenyl)-2-methylbutane, l,l-bis(4-hydroxyphenyl)-p- diisopropylbenzene, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, dimethylbisphenol A, bis(3,5- dimethyl-4-hydroxyphenyl)methane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, bis(3,5- dimethyl-4-hydroxyphenyl)sulfone, 2,4-bis(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutane, 1,1- bis(3,5-dimethyl-4-hydroxyphenyl)-p-diisopropylbenzene and l,l-bis(4-hydroxyphenyl)-3,3,5- trimethylcyclohexane and also the bisphenols (I) to (III) in which R’ in each case stands for Ci - to C4-alkyl, aralkyl or aryl, preferably for methyl or phenyl, very particularly preferably for methyl.

[0037] Particularly preferred dihydroxyaryl compounds are 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, l,l-bis(4-hydroxyphenyl)cyclohexane, 1,1- bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 4,4’-dihydroxybiphenyl, and dimethylbisphenol A and also the diphenols of formulae (I), (II) and (III).

[0038] These and other suitable dihydroxyaryl compounds are described for example in US 3 028 635 A, US 2 999 825 A, US 3 148 172 A, US 2 991 273 A, US 3 271 367 A, US 4 982 014 A und US 2 999 846 A, in DE 1 570 703 A, DE 2063 050 A, DE 2 036 052 A, DE 2 211 956 A and US 2 999 846 A, in DE 1 570 703 A, DE 2063 050 A, DE 2 036 052 A, DE 2 211 956 A and DE 3 832 396 A, in FR 1 561 518, in the monograph “H. Schnell, Chemistry and Physics of Polycarbonates, Interscience Publishers, New York 1964” and also in JP 62039 / 1986 A, JP 62040 / 1986 A and JP 105550 / 1986 A.

[0039] In the case of homopolycarbonates only one dihydroxyaryl compound is used; in the case of copolycarbonates two or more dihydroxyaryl compounds are used. The dihydroxyaryl compounds employed, similarly to all other chemicals and assistants added to the synthesis, may be contaminated with the contaminants from their own synthesis, handling and storage. However, it is desirable to use raw materials of the highest possible purity.

[0040] Suitable carbonic acid derivatives are for example phosgene and diphenyl carbonate.

[0041] Suitable chain terminators that may be used in the production of polycarbonates are monophenols.

[0042] Suitable monophenols are for example phenol itself, alkylphenols such as cresols, p-tert-butylphenol, cumylphenol and mixtures thereof.

[0043] Preferred chain terminators are the phenols mono- or poly substituted by linear or branched C1-C30 alkyl radicals, preferably unsubstituted or substituted by tert-butyl. Particularly preferred chain terminators are phenol, cumylphenol and / or p-tert-butylphenol.

[0044] The amount of chain terminator to be employed is preferably 0.1 to 5 mol% based on the moles of diphenols employed in each case. The addition of the chain terminators may be effected before, during or after the reaction with a carbonic acid derivative.

[0045] Suitable branching agents are the trifunctional or more than trifunctional compounds familiar in polycarbonate chemistry, in particular those having three or more than three phenolic OH groups. Suitable branching agents are for example l,3,5-tri(4-hydroxyphenyl)benzene, l,l,l-tri(4- hydroxyphenyl)ethane, tri(4-hydroxyphenyl)phenylmethane, 2,4-bis(4- hydroxyphenylisopropyl)phenol, 2, 6-bis(2 -hydroxy-5 ’-methylbenzyl)-4-methylphenol, 2-(4- hydroxyphenyl)-2-(2,4-dihydroxyphenyl)propane, tetra(4-hydroxyphenyl)methane, tetra(4-(4- hydroxyphenylisopropyl)phenoxy)methane and l,4-bis((4’,4”-dihydroxytriphenyl)methyl)benzene and 3, 3 -bis(3-methyl-4-hydroxyphenyl)-2 -oxo-2, 3 -dihydroindole. The amount of the branching agents for optional employment is preferably 0.05 mol% to 2.00 mol%, based on moles of dihydroxyaryl compounds used in each case. The branching agents may be either initially charged together with the dihydroxyaryl compounds and the chain terminators in the aqueous alkaline phase or added dissolved in an organic solvent before the phosgenation. In the case of the transesterification process the branching agents are employed together with the dihydroxyaryl compounds. Particularly preferred polycarbonates are the homopolycarbonate based on bisphenol A, the homopolycarbonate based on l,l-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 4,4’- dihydroxybiphenyl, and the copolycarbonates based on the two monomers bisphenol A and 1,1- bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane and also homo- or copolycarbonates derived from the diphenols of formulae (I), (II) and (III) in which R’ in each case stands for Ci - to C4-alkyl, aralkyl or aryl, preferably for methyl or phenyl, very particularly preferably for methyl.

[0046] Preferred are also polycarbonates for the production of which dihydroxyaryl compounds of the following formula (la) have been used:

[0047] (la), wherein

[0048] R5stands for hydrogen or Ci- to C4-alkyl, Ci- to C4-alkoxy, preferably for hydrogen or methyl or methoxy particularly preferably for hydrogen,

[0049] R6, R7, R8and R9mutually independently stand for Ce- to Ci 2-ary 1 or Ci- to C4-alkyl, preferably phenyl or methyl, in particular for methyl,

[0050] Y stands for a single bond, SO2-, -S-, -CO-, -O-, Ci- to Ce-alkylene, C2- to Cs-alkylidene, Ce- to Ci 2-ary lene, which can optionally be condensed with further aromatic rings containing hetero atoms, or for a C5- to Ce-cycloalkylidene residue, which can be singly or multiply substituted with Ci- to C4-alkyl, preferably for a single bond, -O-, isopropylidene or for a Cs-to Ce-cycloalkylidene residue, which can be singly or multiply substituted with Ci- to C4-alkyl,

[0051] V stands for oxygen, C2- to Ce-alkylene or C3- to Ce-alkylidene, preferably for oxygen or C3- alkylene, p, q and r mutually independently each stand 0 or 1, if q = 0, W is a single bond, if q = 1 and r = 0 is, W stands for -O-, C2- to Ce-alkylene or C3- to Ce- alkylidene, preferably for -O- or Cs-alkvicnc. if q = 1 and r = 1, W and V mutually independently stand for C2- to Ce-alkylene or C3- to Ce- alkylidene, preferably for C3 alkylene,

[0052] Z stands for Ci - to Ce-alkylene, preferably C2-alkylene, o stands for an average number of repeating units from 10 to 500, preferably 10 to 100 and m stands for an average number of repeating units from 1 to 10, preferably 1 to 6, particularly preferably 1.5 to 5.

[0053] It is also possible to use dihydroxyaryl compounds, in which two or more siloxane blocks of general formula (la) are linked via terephthalic acid and / or isophthalic acid under formation of ester groups.

[0054] Especially preferable are (poly)siloxanes of the formulae (2) and (3) wherein R1stands for hydrogen, Ci- to Chalky 1, preferably for hydrogen or methyl and especially preferably for hydrogen,

[0055] R2mutually independently stand for aryl or alkyl, preferably for methyl,

[0056] X stands for a single bond, -SO2-, -CO-, -O-, -S-, Ci- to Ce-alkylene, C2- to Cs-alkylidene or for Ce- to Ci 2-ary lene, which can optionally be condensed with further aromatic rings containing hetero atoms,

[0057] X stands for a single bond, -SO2-, -CO-, -O-, -S-, Ci- to Ce-alkylene, C2- to Cs-alkylidene, C5- to Ci2-cycloalkylidene or for Ce- to Ci2-arylene, which can optionally be condensed with further aromatic rings containing hetero atoms,

[0058] X preferably stands for a single bond, isopropylidene, C5- to Ci2-cycloalkylidene or oxygen, and especially preferably stands for isopropylidene, n means an average number from 10 to 400, preferably 10 and 100, especially preferably 15 to 50 and m stands for an average number from 1 to 10, preferably 1 to 6 and especially preferably from 1.5 to 5.

[0059] Also preferably the siloxane block can be derived from one of the following structures: wherein a in formulae (IV), (V) und (VI) means an average number from 10 to 400, preferably from 10 to 100 and especially preferably from 15 to 50.

[0060] It is equally preferable, that at least two of the same or different siloxane blocks of the general formulae (IV), (V) or (VI) are linked via terephthalic acid and / isophthalic acid under formation of ester groups.

[0061] It is also preferable, if p = 0 in formula (la), V stands for G-alkylcnc. if r = 1, Z stands for C2-alkylene, R8and R9stand for methyl, if q = 1, W stands for Cs-alkylene, if m = 1, R5stands for hydrogen or Ci- to Chalky 1, preferably for hydrogen or methyl, R6and R7mutually independently stand for Ci- to Chalky 1, preferably methyl, and o stands for 10 to 500.

[0062] Copolycarbonates with monomer units of the general formula (la), in particular with bisphenol A, and in particular the production of those copolycarbonates are described in WO 2015 / 052106 A2.

[0063] As examples of aromatic polycarbonate suitable for the present invention, mention can be made of those produced from bisphenol A and phosgene, and sold under the trade name Makrolon® 2400, Makrolon® 2600, Makrolon® 2800, Makrolon® 3100 by Covestro Co., Ltd.

[0064] The aromatic polycarbonate is present in the composition according to the present invention in an amount ranging from 90 wt. % to 99 wt. %, preferably from 92 wt. % to 98 wt. %, more preferably from 93 wt. % to 98 wt. %, relative to the total weight of the composition.

[0065] Component B

[0066] The polycarbonate composition of the present invention comprise at least one sulfonated polyester.

[0067] The sulfonated polyester suitable in the context of the present invention preferably is a linear, amorphous and water dispersible copolyisophthalate containing sodiosulfo substituents. The substituents are more preferably derived from 5-(sodiosulfo)-isophthalic acid.

[0068] These polyesters may be prepared in accordance with the procedure disclosed in U. S. Pat. No. 4, 499,262 and U. S. Pat. No. 5, 646, 237 both incorporated herein by reference.

[0069] Preferably, the sulfonated polyester is obtained by a reaction of 35-45 mole % of isophthalic acid, 2-6 mole % of 5-(sodiosulfo)-isophthalic acid, 15-30 mole % of 1, 4-cyclohexanedimethanol, and 25-45 mole % of diethyleneglycol, relative to the total mole numer of isophthalic acid, 5-(sodiosulfo)- isophthalic acid, 1, 4-cyclohexanedimethanol and diethyleneglycol.

[0070] As examples for sulfonated polyesters suitable for the composition of the present invention, mention can be made of those may be obtained from Eastman as AQ polymer grades 38S and 55S.

[0071] AQ polymer grade 38S is based on 39 mole % of isophthalic acid, 5.1 mole % of 5-(sodiosulfo)- isophthalic acid, 26.2 mole % of 1, 4-cyclohexanedimethanol, and 29.7 mole % of diethyleneglycol. The sodium contents derived from 5-(sodiosulfo)-isophthalic acid monomer, of 38S is 2 wt.%.

[0072] AQ polymer grade 55S is based on 41.3 mole % of isophthalic acid, 2.9 mole % of 5-(sodiosulfo)- isophthalic acid, 16.5 mole % of 1, 4-cyclohexanedimethanol, and 39.3 mole % of diethyleneglycol. The sodium contents derived from 5-(sodiosulfo)-isophthalic acid monomer, of 55S are 1.1 wt.%. The general structure of AQ 38S and 55S is shown in formula (VII). where: A = dicarboxylic acid moiety

[0073] G = glycol moiety

[0074] SO3~Na+= sodiosulfo group

[0075] OH = hydroxyl group

[0076] (VII)

[0077] Eastman AQ linear polyesters AQ 38S and 55S are similar to each other in physical form, color, and molecular weight (Table 1). They differ from each other chiefly in glass transition temperature (Tg) and softening point. The 38S shows a glass transition temperature (Tg) of 35 to 38 °C, while a Tgof 55S is 51 to 55 °C . The number in the product name indicates the dry Tgof each polymer.

[0078] Table 1

[0079] The sulfonated polyester is present in an amount ranging from 0.2 wt. % to 0.8 wt. %, preferably from 0.2 wt. % to 0.7 wt. %, relative to the total weight of the polycarbonate composition.

[0080] Component C

[0081] The polycarbonate composition according to the present invention comprises at least one core-shell impact modifier selected from the group consisting of methyl methacrylate-butadiene-styrene (MBS), acrylonitrile-butadiene-styrene (ABS) , silicone-acrylate rubber based impact modifiers and combinations thereof.

[0082] Methyl methacrylate-butadiene-styrene

[0083] Methyl methacrylate-butadiene-styrene (MBS) has a core-shell impact structure, which is described e.g. in DE-OS 2 035 390 or in DE-OS 2 248 242 and in Ullmanns, Enzyklopadie der Technischen Chemie, vol. 19 (1980), p. 280 et seq. Preferably, methyl methacrylate-butadiene-styrene (MBS) comprises 5 wt.% to 95 wt.%, preferably 8 wt.% to 90 wt.%, in particular 20 wt.% to 85 wt.% of units derived from methyl methacrylate and styrene, and 95 wt.% to 5 wt.%, preferably 92 wt.% to 10 wt.%, in particular 80 wt.% to 15 wt.% of units derived from butadiene, based on the weight of methyl methacrylate-butadiene-styrene.

[0084] More preferably, the methyl methacrylate-butadiene-styrene (MBS) comprises 10 wt.% to 35 wt.% of units derived from methyl methacrylate, 5 wt.% to 20 wt.% of units derived from styrene, and 60 wt.% to 85 wt.% of units derived butadiene, based on the weight of methyl methacrylate-butadiene- styrene.

[0085] As commercial products of methyl methacrylate-butadiene-styrene can be used in the present invention, mention can be made to Kane Ace M732 available from Japan Kaneka Chemical Co. Ltd, comprising 10 wt.% to 35 wt.% of units derived from methyl methacrylate, 5 wt.% to 10 wt.% of units derived from styrene, and 60 wt.% to 85 wt.% of units derived butadiene, based on the weight of methyl methacrylate-butadiene-styrene .

[0086] If present, methyl methacrylate-butadiene-styrene is present in the composition according to the present invention in an amount ranging from 0.5 wt. % to 3.5 wt. %, preferably from 1 wt. % to 2.5 wt. %, relative to the total weight of the polycarbonate composition.

[0087] Acrylonitrile-butadiene-styrene

[0088] Acrylonitrile-butadiene-styrene (ABS) has a core-shell impact structure, which is described e.g. in DE 2 035 390 A or in DE 2248 242 A and in Ullmanns, Enzyklopadie der Technischen Chemie, vol. 19 (1980), p. 280 et seq.

[0089] Preferably, the acrylonitrile-butadiene-styrene (ABS) comprises 5 wt.% to 95 wt.%, preferably 8 wt.% to 90 wt.%, in particular 20 wt.% to 85 wt.% of units derived from acrylonitrile and styrene, and 95 wt.% to 5 wt.%, preferably 92 wt.% to 10 wt.%, in particular 80 wt.% to 15 wt.% of units derived from butadiene, based on the weight of acrylonitrile-butadiene-styrene.

[0090] More preferably, the acrylonitrile-butadiene-styrene (ABS) comprises 5 wt.% to 20 wt.% of units derived from acrylonitrile, 20 wt.% to 55 wt.% of units derived from styrene, and 75 wt.% to 30 wt.% of units derived butadiene, based on the weight of acrylonitrile-butadiene-styrene.

[0091] As commercial products of acrylonitrile-butadiene-styrene can be used in the present invention, mention can be made of ABS HRG powder P60 available from Styrolution, produced by emulsion polymerisation of 42-45 wt. %, based on the ABS polymer, of a mixture of 27 wt. % acrylonitrile and 73 wt. % styrene in the presence of 55-58 wt. %, based on the ABS polymer, of a crosslinked polybutadiene rubber (the average particle diameter dso is 0.3 pm).

[0092] If present, acrylonitrile-butadiene-styrene is present in the composition according to the present invention in an amount ranging from 0.5 wt. % to 3.5 wt. %, preferably from 1 wt. % to 2.5 wt. %, relative to the total weight of the polycarbonate composition.

[0093] Silicone-acrylate rubber based impact modifiers

[0094] The silicone-acrylate rubber based impact modifier has a core-shell impact structure.

[0095] Preferably, the silicone-acrylate rubber based impact modifier comprises,

[0096] C. 1) 5 wt.% to 90 wt.%, preferably 8 wt.% to 80 wt.%, in particular 10 wt.% to 70 wt.%, of at least one vinyl monomer on

[0097] C.2) 95 wt.% to 10 wt.%, preferably 92 wt.% to 20 wt.%, in particular 90 wt.% to 30 wt.%, of one or more silicone-acrylate rubbers as a graft base, the wt.% is calculated based on the weight of the impact modifier.

[0098] The vinyl monomers are used to form polymer chains and these are chemically bonded to the graft substrate.

[0099] Preferably, the vinyl monomer C. 1 is selected from vinylaromatics and / or vinylaromatics substituted on the nucleus (such as styrene, a-methylstyrene, -mcthylstyrcnc). vinyl cyanides (unsaturated nitriles, such as acrylonitrile and methacrylonitrile), (Ci -Cs)-alkyl (meth)acrylates, such as methyl methacrylate, ethyl methacrylate, n-butyl acrylate, t-butyl acrylate, and derivatives (such as anhydrides and imides) of unsaturated carboxylic acids, for example maleic anhydride and A-phcnyl- maleimide.

[0100] More preferably, the at least one vinyl monomer C.l comprises (meth)acrylic acid (Ci-Cs)-alkyl esters or its combination with styrene, a-methylstyrene or -mcthylstyrcnc.

[0101] In some embodiments, monomers C. l is a mixture of C.1.1) 50 to 99, preferably 60 to 80, especially 70 to 80 parts by weight, based on C.2.1, of vinylaromatics and / or ring-substituted vinylaromatics (such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p- chlorostyrene) and / or (Cl-C8)-alkyl methacrylates, such as methyl methacrylate, ethyl methacrylate, and

[0102] C.1.2) 1 to 50, preferably 20 to 40, especially 20 to 30 parts by weight, based on C.2.1, of (C1-C8)- alkyl (meth)acrylates, such as methyl methacrylate, n-butyl acrylate, tert-butyl acrylate, and / or derivatives (such as anhydrides and imides) of unsaturated carboxylic acids, for example maleic anhydride and N-phenylmaleimide.

[0103] Preferred monomers C.1.1 are selected from at least one of the monomers styrene, methylstyrene and methyl methacrylate; preferred monomers C.1.2 are selected from at least one of the monomers maleic anhydride and methyl methacrylate. Particularly preferred monomers are C.1.1 = C.1.2 methyl methacrylate.

[0104] A silicone-acrylate composite rubber or a mixture of different silicone-acrylate composite rubbers can be employed as the graft substrate C.2. These silicone-acrylate composite rubbers are preferably composite rubbers having graft-active sites containing:

[0105] C.2.1) 5 wt.%-95 wt.%, preferably 20 wt.% to 80 wt.%, particularly preferably 25 wt.% to 50 wt.%, of silicone rubber proportion, and

[0106] C.2.2) 95 wt.% to 5 wt.%, preferably 80 wt.% to 20 wt.%, particularly preferably 75 wt.% to 50 wt.%, of poly alkyl (meth)acrylate rubber proportion, wherein the two rubber components penetrate one another in the composite rubber and are therefore essentially inseparable.

[0107] The particularly preferred proportions of silicone rubber and polyalkyl (meth)acrylate rubber results in a particularly advantageous combination of good mechanical properties, good surface of the component parts and good resistance toward hydrolytic molecular weight degradation and the influence of chemicals.

[0108] Silicone-acrylate composite rubbers are known and are described for example in US 5,807,914 A, EP 430134 A2 and US 4888388 A.

[0109] Suitable silicone rubber components C.2.1 of the silicone-acrylate composite rubbers are silicone rubbers having graft-active sites, the production method therefor is described for example in US 2891920 A, US 3294725 A, DE-A 3 631 540, EP 249964 A2, EP 430134 A2 and US 4888388 A.

[0110] The silicone rubber according to C.2.1 is preferably produced by emulsion polymerization in which siloxane monomer units, crosslinking or branching agents and optionally grafting agents are used.

[0111] Examples of preferably siloxane monomer for production of silicone rubber include dimethylsiloxane or cyclic organosiloxanes having at least 3 ring members, preferably 3 to 6 ring members, for example and with preference hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxanes, tetramethyltetraphenylcyclotetrasiloxanes, octaphenylcyclotetrasiloxane.

[0112] The organo siloxane monomers may be used alone or in the form of a mixture comprising 2 or more monomers.

[0113] Preferably crosslinking agents are silane-based crosslinking agents having a functionality of 3 or 4, particularly preferably 4. Preferred examples include: trimethoxy methylsilane, triethoxyphenylsilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxy silane and tetrabutoxysilane. The crosslinking agent can be used alone or in a mixture of two or more. Particular preference is given to tetraethoxy silane.

[0114] Examples of grafting agents include P-methacryloyloxyethyl dimethoxymethylsilane, y- ethacryloyloxypropyl methoxydimethylsilane, y-methacryloyloxypropyl dimethoxymethylsilane, y- methacryloyloxypropyl trimethoxysilane, y-methacryloyloxypropyl ethoxydiethylsilane, y- methacryloyloxypropyl diethoxy methylsilane, 5-methacryloyloxybutyl diethoxymethylsilane or mixtures thereof.

[0115] It is preferable to use 0-20 wt.% of grafting agent based on the total weight of the silicone rubber.

[0116] The silicone rubber may be produced by emulsion polymerization as described for example in US 2891920 A and US 3294725 A.

[0117] Suitable polyalkyl(meth)acrylate rubber components C.2.2 of the silicone-acrylate-composite rubbers may be produced from alkyl methacrylates and / or alkyl acrylates, a crosslinking agent and a grafting agent.

[0118] Examples of preferred alkyl methacrylates and / or alkyl acrylates include the Cl- to C8-alkyl esters, for example methyl, ethyl, n-butyl, t-butyl, n-propyl, n-hexyl, n-octyl, n-lauryl and 2-ethylhexyl esters; haloalkyl esters, preferably halo-(Cl-C8)-alkyl esters, such as chloroethyl acrylate, and mixtures of these monomers. Particular preference is given to n-butyl acrylate.

[0119] Useful crosslinking agents for the polyalkyl(meth)acrylate rubber component of the siliconeacrylate rubber include monomers having more than one polymerizable double bond. Preferred examples of crosslinking monomers are esters of unsaturated monocarboxylic acids having 3 to 8 carbon atoms and unsaturated monohydric alcohols having 3 to 12 carbon atoms or saturated polyols having 2 to 4 OH groups and 2 to 20 carbon atoms, such as ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate and 1,4-butylene glycol dimethacrylate. The crosslinking agents can be used alone or in mixtures of at least two crosslinking agents.

[0120] Examples of preferred grafting agents include allyl methacrylate, triallyl cyanurate, triallyl isocyanurate or mixtures thereof. Allyl methacrylate may also be used as the crosslinking agent. The grafting agents can be used alone or in mixtures of at least two grafting agents.

[0121] The amount of crosslinking agent and grafting agent is 0.1 wt.% to 20 wt.% based on the total weight of the polyalkyl (meth)acrylate rubber component of the silicone-acrylate rubber.

[0122] The silicone-acrylate-composite rubber is produced by first producing the silicone rubber of C.2.1 in the form of an aqueous latex. This latex is then enriched with the alkyl methacrylates and / or alkyl acrylates to be used, the crosslinking agent and the grafting agent and a polymerization is performed.

[0123] The silicone-acrylate composite graft rubbers are produced by grafting the monomers onto the rubber substrate C.2. This can be carried out using the polymerization methods described in EP 249964 A2, EP 430134 A2 and US 4888388 A for example.

[0124] As silicone-acrylate rubber, mention can be made of silicone-(Ci-Cs) alkyl acrylate rubber. In particular, silicone-butylacrylate rubber can be mentioned as an example.

[0125] Preferably, the silicone-acrylate rubber based impact modifier is selected from (meth)acrylic acid (Ci -Cs)-alkyl ester-grafted silicone-(Ci-Cs) alkyl acrylate rubber.

[0126] More preferably, the silicone-acrylate rubber based impact modifier is a methyl methacrylate-grafted silicone-butyl acrylate rubber.

[0127] As an example of commercially available silicone-acrylate rubber based impact modifier can be used in the present invention, mention can be made of Metablen S-2001, Metablen S-2030, Metablen S- 2100, and Metablen® S2130 from Mitsubishi Rayon Co., Ltd.

[0128] In some embodiments, methyl methacrylate-grafted silicone-butyl acrylate rubber e.g. Metablen® S2130 and Metablen S2100 are used as a second impact modifier. If present, silicone-acrylate rubber based impact modifier is present in the composition according to the present invention in an amount ranging from 0.5 wt. % to 3.5 wt. %, preferably from 1 wt. % to 2.5 wt. %, relative to the total weight of the polycarbonate composition.

[0129] According to some embodiments, the composition according to the present invention comprises from 0.5 wt.% to 3.5 wt.% of of methyl methacrylate-butadiene-styrene, relative to the total weight of the composition.

[0130] According to some embodiments, the composition according to the present invention comprises from 0.5 wt.% to 2.5 wt.% of acrylonitrile-butadiene-styrene, relative to the total weight of the composition.

[0131] Accroding to some embodiments, the composition according to the present invention comprises from 0.5 wt.% to 3.5 wt.% of a silicone-acrylate rubber based impact modifier, relative to the total weight of the composition.

[0132] The core-shell impact modifier selected from the group consisting of methyl methacrylate-butadiene- styrene (MBS), acrylonitrile-butadiene-styrene (ABS), silicone-acrylate rubber based impact modifiers and combinations thereof is present in the polycarbonate composition according to the present invention in an amount ranging from 0.5 wt.% to 3.5 wt.%, preferably from 0.5 wt.% to 3 wt.%, relative to the total weight of the polycarbonate composition.

[0133] Component D

[0134] The polycarbonate composition according to the present invention comprises polytetrafluoroethylene.

[0135] Polytetrafluoroethylene is used as an anti-dripping agent in the polycarbonate composition according to the present invention.

[0136] Polytetrafluoroethylene 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 peroxodisulfate, at pressures of from 7 kg / cm2to 71 kg / cm2and at temperatures of from 0 °C to 200 °C, preferably at temperatures of from 20 to 100°C, for further details see e.g. U.S. patent application 2 393 967 A.

[0137] Preferably, the polytetrafluoroethylene have a density of from 1.2 g / cm3to 2.3 g / cm3. More preferably, the polytetrafluoroethylene used according to the invention has a mean particle diameter of from 0.05 pm to 20 pm, preferably from 0.08 pm to 10 pm, and a density of from 1.2 g / cm3to 1.9 g / cm3.

[0138] Polytetrafluoroethylene can be used alone or as a master batch with a homopolymer or copolymer of styrene or methyl methacrylate.

[0139] As an example of commercial products of polytetrafluoroethylene, mention can be made of those sold under the trade name Teflon®, such as Teflon® 30 N by DuPont.

[0140] A master batch of polytetrafluoroethylene and styrene-acrylonitrile (SAN) in a weight ratio of 1 : 1, for example, ADS 5000 available from Chemical Innovation Co., Ltd. Thailand and POLYB FS- 200 available from Han Nanotech Co., Ltd, can be used.

[0141] Polytetrafluoroethylene is present in the polycarbonate composition in an amount ranging from 0.2 wt.% to 0.5 wt.%, preferably from 0.2 wt.% to 0.4 wt.%, relative to the total weight of the polycarbonate composition.

[0142] Additional components

[0143] In addition to components A-D mentioned above, the polycarbonate compositions according to the present invention can optionally comprise one or more additives conventionally used in polycarbonate compositions as additional components. Such additives are, for example, UV stabilizers, IR stabilizers, heat stabilizers, antistatic agents, pigments (such as carbon black), colorants, lubricants (such as waxes), demoulding agents (such as pentaerythrityl tetrastearate), antioxidants, pH adjusters, flow improvers agents, etc. and combinations thereof.

[0144] The person skilled in the art can select the type of the additives so as not to adversely affect the desired properties of the polycarbonate composition according to the present invention.

[0145] Preferably, the composition according to the present invention further comprises, up to 5 wt.%, preferably up to 3 wt.%, more preferably from 0.1 wt.% to 3 wt.%, based on the total weight of composition, an additional component selected from the group consisting of antioxidants, heat stabilizers, demoulding agents, antistatic agents, pigments, pH adjusters, and lubricants.

[0146] Preferably, the composition according to the present invention consists of components A)-D) defined above and an optional component selected from the group consisting of antioxidants, heat stabilizers, demoulding agents, antistatic agents, pigments, pH adjusters, and lubricants. Preferably, the polycarbonate composition according to the present invention comprises, relative to the total weight of the composition:

[0147] A) 90-97 wt.% of an aromatic polycarbonate based on bisphenol A,

[0148] B) 0.2-0.7 wt. % of a sulfonated polyester obtained by a reaction of 35-45 mole % of isophthalic acid, 2-6 mole % of 5 -(sodiosulfo) -isophthalic acid, 15-30 mole % of 1, 4- cyclohexanedimethanol, and 25-45 mole % of diethyleneglycol, relative to the total mole numer of isophthalic acid, 5-(sodiosulfo)-isophthalic acid, 1, 4-cyclohexanedimethanol and diethyleneglycol,

[0149] C) 0.5-3 wt.% of a core-shell impact modifier selected from acrylonitrile-butadiene-styrene, methyl methacrylate-butadiene-styrene and methyl methacrylate-grafted silicone-butyl acrylate rubber, and

[0150] D) 0.2-0.4 wt.% of polytetrafluoroethylene.

[0151] Preferably, the total amount of components A)-D) as defined above is from 95 wt.% to 100 wt.%, preferably from 97 wt.% to 100 wt.%, more preferably from 97 wt.% to 99.5 wt.%, based on the total weight of the polycarbonate composition according to the present invention.

[0152] The inventors have found unexpectedly that a synergetic effect in terms of flame-retardency can be obtained with the combination of a sulfonated polyester and a core-shell impact modifier selected from the group consisting of methyl methacrylate-butadiene-styrene (MBS), acrylonitrile-butadiene- styrene (ABS) , silicone-acrylate rubber based impact modifiers and combinations thereof.

[0153] Preparation of the polycarbonate composition

[0154] The polycarbonate composition according to the present invention can be in the form of, for example, pellets.

[0155] The polycarbonate composition according to the present invention demonstrates a good processing behaviour and can be prepared by a variety of methods involving intimate admixing of the materials desired in the composition.

[0156] For example, the materials desired in the composition are first blended in a high speed mixer. Low shear processes, including but not limited to hand mixing, can also accomplish this blending. The blend can then be fed into the throat of a twin-screw extruder via a hopper. Alternatively, at least one of the components can be incorporated into the composition by feeding it directly into the extruder at the throat and / or downstream through a side staffer. Additives can also be compounded into a masterbatch with a desired polymeric resin and fed into the extruder. The extruder is generally operated at a temperature higher than that necessary to cause the composition to flow. The extrudate is immediately quenched in a water bath and pelletized. The pellets can be one-fourth inch long or less as described. Such pellets can be used for subsequent molding, shaping or forming.

[0157] Melt blending methods are preferred due to the availability of melt blending equipment in commercial polymer processing facilities.

[0158] Illustrative examples of equipment used in such melt processing methods include co-rotating and counter-rotating extruders, single screw extruders, co-kneaders, and various other types of extrusion equipment.

[0159] The temperature of the melt in the processing is preferably minimized in order to avoid excessive degradation of the polymers. It is often desirable to maintain the melt temperature between 220 °C and 320 °C in the molten resin composition, although higher temperatures can be used provided that the residence time of the resin in the processing equipment is kept short.

[0160] In some cases, the melting composition exits from a processing equipment such as an extruder through small exit holes in a die. The resulting strands of the molten resin are cooled by passing the strands through a water bath. The cooled strands can be chopped into small pellets for packaging and further handling.

[0161] Shaped articles

[0162] The polycarbonate compositions according to the present invention can be used, for example for the production of various types of shaped articles.

[0163] In the second aspect, the present invention also provides a shaped article made from a polycarbonate composition according to the first aspect of the present invention.

[0164] Preferably, the shaped article is a housing or part of a house of electrical and electronics, for example, e.g. printers, copiers, chargers, TV projectors, notebook, pad, game consoles, etc.

[0165] Preparation of shaped articles

[0166] The polycarbonate compositions according to the present invention can be processed into shaped articles by a variety of means such as injection moulding, extrusion moulding, blow moulding or thermoforming to form shaped articles.

[0167] In the third aspect, the present invention provides a process for preparing the shaped article made from a composition according to the first aspect of the present invention, comprising injection moulding, extrusion moulding, blow moulding or thermoforming the polycarbonate composition according to the present invention.

[0168] Examples

[0169] The present invention will be illustrated in detail below with reference to the examples below. The examples are only for the purpose of illustration, rather than limiting the scope of the present invention.

[0170] Materials used

[0171] Component A

[0172] PC-1: available from the company Covestro Polymer (China), a linear polycarbonate based on bisphenol A having a weight average molecular weight (Mw) of 26000 g / mol, as determined by means of Gel Permeation Chromatography (GPC) in methylene chloride at 25 °C using polycarbonate standards.

[0173] PC-2: available from the company Covestro Polymer (China), a linear polycarbonate based on bisphenol A have a weight average molecular weight of 30000 g / mol, as determined by means of Gel Permeation Chromatography (GPC) in methylene chloride at 25 °C using polycarbonate standards.

[0174] Component B

[0175] AQ 38S: a sulfonated polyester based on 39 mole % of isophthalic acid, 5.1 mole % of 5-(sodiosulfo)- isophthalic acid, 26.2 mole % of 1, 4-cyclohexanedimethanol, and 29.7 mole % of diethyleneglycol, a commercially available product from Eastman.

[0176] AQ 55S: a sulfonated polyester based on 41.3 mole % of isophthalic acid, 2.9 mole % of 5- (sodiosulfo)-isophthalic acid, 16.5 mole % of 1, 4-cyclohexanedimethanol, and 39.3 mole % of diethyleneglycol, a commercially available product from Eastman.

[0177] Component C

[0178] ABS: produced by emulsion polymerisation of 42-45 wt. %, based on the ABS polymer, of a mixture of 27 wt. % acrylonitrile and 73 wt. % styrene in the presence of 55-58 wt. %, based on the ABS polymer, of a crosslinked polybutadiene rubber, available as ABS HRG powder P60 from Styrolution.

[0179] MBS: Methyl methacrylate-butadiene-styrene, available as Kane Ace M732 from the company Japan Kaneka Chemical Co., Ltd.

[0180] S-2130: Silicone-acrylate rubber based impact modifier, available as Metablen S-2130 from the company Mitsubishi Chemical Corporation. Component D

[0181] PTFE-SAN: Anti -dripping agent, polytetrafluoroethylene (PTFE) capped by styrene-acrylonitrile copolymer (SAN) with a weight ratio of PTFE: SAN = 1:1, available as ADS5000 from IRPC Public Company Limited.

[0182] Other components

[0183] PETS: pentaerythritol tetrastearate, a demolding agent, available as FAQ L348 from FACI Asia Pacific Pte Ltd (Singapore).

[0184] B900: a mixture of 80% Irgafos® 168 and 20% Irganox® 1076 available from the company BASF, wherein Irgafos®168 is (tris (2,4-di-tert-butylphenyl)phosphite), Irganox® 1076 is (2,6- di-tert-butyl-4-(octadecanoxy-carbonylethyl)-phenol.

[0185] Paraloid EXL2300: an acrylate rubber based impact modifier, available as Paraloid EXL2300 from the company Dow Chemicals.

[0186] Test methods

[0187] The physical properties of specimens in the examples were tested as follows.

[0188] Melt volume flow rate (MVR)

[0189] The melt volume flow rate (MVR) was determined according to ISO 1133: 2011 at 300 °C and a loading of 1.2 kg with a Zwick 4106 instrument from Roell.

[0190] Izod notched impact strength

[0191] Izod notched impact strength was measured on specimens with dimensions of 80 mm * 10 mmz3 mm according to IS0180 / 1A:2000 (23 °C or 0°C, 3 mm, 5.5J).

[0192] Buring behavior

[0193] UL94 @1.5 mm: measured on 125 mm x 12.5 mm bars with 1.5 mm thickness according to UL94: 2015.

[0194] Comparative Examples (CE) 1-6

[0195] The materials listed in Table 2 were compounded on a twin-screw extruder (ZSK-26) (from Coperion, Werner and Pfleiderer) at a speed of rotation of 225 rpm, a throughput of 30 kg / h, and a machine temperature of 240 °C -290 °C and granulated.

[0196] The pellets obtained were processed into corresponding testing specimens on an injection moulding machine (from Arburg) with a melting temperature of 240-300 °C a mold temperature of 80 °C, and a flow front velocity 240 mm / s. The properties (including Izod notched impact strength and burning behavior) of the molded parts based on compositions obtained were tested and the results were summarized in Table 2.

[0197] Table 2

[0198] It can be seen from Table 2 that the molded parts based on comparative examples 1-6 not comprising a core-shell impact modifier selected from methyl methacrylate-butadiene-styrene, acrylonitrile- butadiene-styrene, silicone-acrylate rubber based impact modifiers and combinations thereof, have a flame retardant level of UL94 V2 at the thickness of 1.5 mm and an IZOD notched impact strength at 0 °C which shows brittle behavior. Comparative Examples (CE) 7-18

[0199] Similarly, the materials listed in Table 3 were compounded, the properties of the molded parts based on compositions obtained were tested and the results were summarized in Table 3.

[0200]

[0201] Table 3

[0202] It can be seen from Table 3 that the molded parts based on comparative examples 7-17 not comprising a sulfonated polyester, but polycarbonate, impact modifier and PTFE, cannot achieve a flame retardant level of UL94 VO or even VI at the thickness of 1.5 mm.

[0203] Inventive Examples (IE) 1-12

[0204] Similarly, the materials listed in Table 4 were compounded, the properties of the molded parts based on compositions were tested and the results were summarized in Table 4.

[0205] Table 4

[0206] It can be seen from Table 4 that the molded parts based on inventive examples 1-12 can achieve a flame

[0207] 2 retardant level of UL94 VO at the thickness of 1.5 mm, an impact strength of more than 54 kJ / m at 0

[0208] 2

[0209] °C and more than 58 kJ / m at 23 °C as determined according to ISO 180 / A:2000.

[0210] It can be seen from a comparison between inventive examples 1-12 and comparative examples 1-18 that a combination of a sulfonated polyester and MBS will result in a synergistic effect in terms of flame retardancy.

[0211] Inventive Examples (IE) 13-17

[0212] Similarly, the materials listed in Table 5 were compounded, the properties of the molded parts based on compositions were tested and the results were summarized in Table 5.

[0213] Table 5

[0214] It can be seen from Table 5 that the molded parts based on inventive examples 13-17 can achieve a

[0215] 2 flame retardant level of UL94 VO at the thickness of 1.5 mm, an impact strength more than 54 kJ / m at

[0216] 2

[0217] 0 °C and more than 58 kJ / m at 23 °C as determined according to ISO 180 / A:2000.

[0218] It can be seen from a comparison between inventive examples 13-17 and comparative examples 1-18 that a combination of a sulfonated polyester and ABS will result in a synergistic effect in terms of flame retardancy. Inventive Examples (IE) 18-22

[0219] Similarly, the materials listed in Table 6 were compounded, the properties of the molded parts based on compositions obtained were tested and the results were summarized in Table 6.

[0220] Table 6

[0221] It can be seen from Table 6 that the molded parts based on inventive examples 18-22 can achieve a 2 flame retardant level of UL94 VO at the thickness of 1.5 mm, an impact strength of more than 54 kJ / m 2 at 0 °C and more than 58 kJ / m at 23 °C as determined according to ISO 180 / A:2000.

[0222] It can be seen from a comparison between inventive examples 18-22 and comparative examples 1-18 that a combination of a sulfonated polyester and silicone-acrylate rubber based impact modifiers and combinations thereof will result in a synergistic effect in terms of flame retardancy.

[0223] Comparative Examples (CE) 19-27

[0224] Similarly, the materials listed in Table 7 were compounded, the properties of the molded parts based on compositions obtained were tested and the results were summarized in Table 7. Table 7

[0225] It can be seen from Table 7 that the molded parts based on comparative examples 19-20 comprising more than 0.8 wt% of a sulfonated polyester and those based on comparative examples 21-22 and 24- 25 comprising less than 0.2 wt% of a sulfonated polyester cannot achieve a flame retardant level of UL94 VO at the thickness of 1.5 mm.

[0226] Meanwhile, the molded part based on comparative example 23 comprising more than 3.5% of MBS cannot achieve a flame retardant level of UL94 VO at the thickness of 1.5 mm.

[0227] The molded parts based on comparative examples 26-27 comprising Paraloid EXL2300 (which is an acrylate rubber based impact modifier) instead of a core-shell impact modifier selected from methyl methacrylate-butadiene-styrene, acrylonitrile-butadiene-styrene, silicone-acrylate rubber based impact modifiers and combinations thereof, cannot achieve a flame retardant level of UL94 VO at the thickness of 1.5 mm.

[0228] In summary, the combination of a sulfonated polyester and of a core-shell impact modifier selected from methyl methacrylate-butadiene-styrene, acrylonitrile-butadiene-styrene, silicone-acrylate rubber based impact modifiers and combinations thereof within optimal loading ranges can lead to a flame retardant level of UL94 VO at the thickness of 1.5 mm and excellent notched impact strength at a low temperature of 0 °C and 23 °C for polycarbonate compositions. The polycarbonate compositions based on such combination can meet the related flame retardancy regulations, such as Blue Angel and REACH, and toughness requirements for electrical housing application.

Claims

Claims1. A polycarbonate composition comprising the following components, relative to the total weight of the composition:A) 90-99 wt.% of one or more aromatic polycarbonate,B) 0.2-0.8 wt.% of one or more sulfonated polyester,C) 0.5-3.5 wt.% of one or more core-shell impact modifier selected from the group consisting of methyl methacrylate-butadiene-styrene, acrylonitrile-butadiene-styrene, silicone-acrylate rubber based impact modifiers and combinations thereof, andD) 0.2-0.5 wt.% of polytetrafluoroethylene.

2. The polycarbonate composition according to claim 1, wherein the sulfonated polyester is obtained by a reaction of 35-45 mole % of isophthalic acid, 2-6 mole % of 5-(sodiosulfo)-isophthalic acid, 15-30 mole % of 1, 4-cyclohexanedimethanol, and 25-45 mole % of diethyleneglycol, relative to the total mole number of isophthalic acid, 5-(sodiosulfo)-isophthalic acid, 1, 4-cyclohexanedimethanol and diethyleneglycol.

3. The polycarbonate composition according to claim 1 or 2, wherein methyl methacrylate-butadiene- styrene is contained and the methyl methacrylate-butadiene-styrene comprises 10 wt.% to 35 wt.% of units derived from methyl methacrylate, 5 wt.% to 20 wt.% of units derived from styrene, and 60 wt.% to 85 wt.% of units derived butadiene, based on the weight of methyl methacrylate-butadiene-styrene.

4. The polycarbonate composition according to any of claims 1-3, wherein methyl methacrylate- butadiene-styrene is present in an amount ranging from 0.5 wt. % to 3.5 wt. %, preferably from 1 wt. % to 2.5 wt. %, relative to the total weight of the polycarbonate composition.

5. The polycarbonate composition according to any of claims 1-4, wherein acrylonitrile-butadiene- styrene is contained and the acrylonitrile-butadiene-styrene comprises 5 wt.% to 20 wt.% of units derived from acrylonitrile, 20 wt.% to 55 wt.% of units derived from styrene, and 75 wt.% to 30 wt.% of units derived butadiene, based on the weight of acrylonitrile-butadiene-styrene.

6. The polycarbonate composition according to any of claims 1-5, wherein acrylonitrile-butadiene- styrene is present in an amount ranging from 0.5 wt. % to 3.5 wt. %, preferably from 1 wt. % to 2.5 wt. %, relative to the total weight of the polycarbonate composition.

7. The polycarbonate composition according to any of claims 1-6, wherein the silicone-acrylate rubber based impact modifier is selected from (Ci-Cs)-alkyl (meth)acrylates-grafted silicone-(Ci-Cs) alkyl acrylate rubber.

8. The polycarbonate composition according to claim 7, wherein the silicone-acrylate rubber based impact modifier is a methyl methacrylate-grafted silicone-butyl acrylate rubber.

9. The polycarbonate composition according to any of claims 1-8, wherein silicone-acrylate rubber based impact modifier is present in the composition according to the present invention in an amount ranging from 0.5 wt. % to 3.5 wt. %, preferably from 1 wt. % to 2.5 wt. %, relative to the total weight of the polycarbonate composition.

10. The polycarbonate composition according to any of claims 1-9, wherein polytetrafluoroethylene is present in an amount ranging from 0.2 wt.% to 0.4 wt.%, relative to the total weight of the polycarbonate composition.

11. Composition according to any of Claims 1-10, comprising, relative to the total weight of the composition:A) 93-98 wt.% of an aromatic polycarbonate based on bisphenol A,B) 0.2-0.7 wt. % of a sulfonated polyester obtained by a reaction of 35-45 mole % of isophthalic acid, 2-6 mole % of 5-(sodiosulfo)-isophthalic acid, 15-30 mole % of 1, 4-cyclohexanedimethanol, and 25-45 mole % of diethyleneglycol, relative to the total mole number of isophthalic acid, 5-(sodiosulfo)- isophthalic acid, 1, 4-cyclohexanedimethanol and diethyleneglycol,C) 0.5-3 wt.% of a core-shell impact modifier selected from the group consisting of acrylonitrile-butadiene-styrene, methyl methacrylate-butadiene-styrene and methyl methacrylate-grafted silicone-butyl acrylate rubber, andD) 0.2-0.4 wt.% of polytetrafluoroethylene.

12. Composition according to any of claims 1-11, wherein the total amount of components A)-D) as defined above is from 95 wt.% to 100 wt.%, preferably from 97 wt.% to 100 wt.%, more preferably from 97 wt.% to 99.5 wt.%, based on the total weight of the composition.

13. A shaped article made from the composition according to any of claims 1 to 12.

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