CA2494351C - Impact-resistance modified polycarbonate blends - Google Patents

Abstract

Composition containing A) 40 to 90 parts by weight of aromatic polycarbonate having a weight-average molecular weight M w of >= 25,000 g/mol, B) 0.5 to 15 parts by weight of polyalkylene terephthalate, C) 1 to 20 parts by weight of graft (co)polymer having a core-shell morphology, consisting of 10 to 90 wt.% (relative to the graft (co)polymer) of a graft base having a glass transition temperature below 0°C and 90 to 10 wt.% (relative to the graft (co)polymer) of vinyl monomers as graft monomers, the graft monomers containing a proportion of at least 20 wt.% (relative to the graft monomers) of acrylate monomers, D) 2 to 20 parts by weight of an oligomeric organic phosphoric acid ester and E) 0 to 1 part by weight of fluorinated polyolefin, the sum of the parts by weight of all components being 100.

Description

Impact-resistance modified polycarbonate blends The invention concerns impact-modified blends containing poly(ester)carbonate having an average molecular weight (Mw) of ?25,000 g/mol, aromatic polyesters, graft copolymers having a graft shell containing acrylate monomer and oligomeric phosphoric acid esters as flame retardants.

Impact-modified blends of polycarbonate and aromatic polyesters are known.
For example, US-A 4,888,388 describes compositions consisting of polycarbonate, polyethylene terephthalate and a graft polymer based on a silicone-butyl acrylate composite rubber, which are distinguished by improved low temperature impact strength. Flame-resistant moulding compositions are not described.

Flame-resistant, impact-modified blends of polycarbonate and aromatic polyesters are also known.

JP 04 345 657-A2 describes mixtures of halogenated aromatic polycarbonate, aromatic polyesters and graft polymers based on silicone-acrylate composite rubbers.
Likewise based on halogen-containing flame retardants are the moulding compositions described in JP 06 239 965-A. In addition to aromatic polycarbonate and aromatic polyesters, they contain graft polymers based on silicone-acrylate composite rubbers and halogenated epoxy resins. The moulding compositions described in WO 94/11429 contain polycarbonate, polyester and a halogenated aryl phosphate as flame retardant. Such compositions that additionally contain methacrylate/butadiene/styrene elastomers having a core-shell structure are also described.

Since moulding compositions rendered flame-resistant with halogen-containing additives can cause mould corrosion through the release of halogen-containing gases Le A 36-132-Foreign during processing and release toxic and corrosive hydrogen halides during combustion, it is desirable to develop halogen-free flame-resistant moulding compositions.

Halogen-free flame-resistant impact-modified blends of polycarbonate and aromatic polyesters are also known.

JP 2001 031 860-A describes compositions with high impact resistance, chemical and hydrolysis resistance, which contain polycarbonate, a mixture of polyethylene and polybutylene terephthalate, a graft elastomer having a core-shell structure, a silicate salt and stabilised red phosphorus and polytetrafluoroethylene (PTFE) as flame retardant. Such moulding compositions do not display adequate strength for many applications, and cannot be formulated in light colours, as required by the IT
industry, for example, for housings for monitors, printers, etc.

US-A 5,030,675 describes moulding compositions consisting of polycarbonate, polyalkylene terephthalate, emulsion ABS graft polymers, monophates as flame retardant and fluorinated polyolefins as antidripping agents. The moulding compositions are characterised by improved weld line strength, but display a comparatively low level of impact resistance. Furthermore, the flame retardants used tend to bleed, which can lead to considerable disruptions during processing.

The problem of the volatility of the flame retardant is solved by the use of oligomeric phosphoric acid esters, as described in EP-A 0 594 021. The PC/ABS
compositions disclosed here contain polyalkylene terephthalate as well as oligophosphoric acid esters and fluorinated polyolefin as flame retardant and display a good notched impact resistance, stress cracking resistance, augmented by high heat resistance and a perfect surface finish. However, they generally display inadequate weld line strength and an unfavourable processing latitude, i.e. at elevated processing temperatures there is a marked deterioration in substantial properties such as chemical resistance, for example.

The compositions that are described in EP-A 0 829 517, EP-A 0 884 366 and JP

073 692-A are likewise rendered flame-resistant with oligophosphoric acid esters.
The PC/PET moulding compositions described here contain, in addition to the flame retardant and optionally other additives, a graft polymer with methyl methacrylate in the graft shell. MBS and MMA-grafted polybutadiene rubbers are described as examples of such graft polymers. The moulding compositions described in these documents are distinguished inter alia by an improved resistance to chemicals and oils.

The present invention provides compositions which are distinguished by a combination of excellent mechanical performance, i.e. high notched impact resistance, weld line strength, elongation at break in the tensile test and stress cracking resistance under chemical attack, flame resistance down to low wall thicknesses and good processability in injection moulding, i.e. a broad processing latitude.

It was found that compositions containing aromatic poly(ester)carbonate having a weight-average molecular weight MW of >25,000 g/mol, polyalkylene terephthalate having an intrinsic viscosity N of _<0.8 cm3/g, graft copolymer having a core-shell structure and a content of acrylate monomers in the graft shell of at least 20 wt.%, and an oligomeric organic phosphoric acid ester display the desired range of properties.

The present invention therefore provides compositions containing A) 40 to 90 parts by weight, preferably 50 to 80 parts by weight, in particular 60 to 80 parts by weight of aromatic poly(ester)carbonate having a weight-average molecular weight M,,, of X5,000 g/mol, preferably X6,000 g/mol, B) 0,5 to 15 parts by weight, preferably 1 to 12 parts by weight, particularly preferably 3 to 10 parts by weight, most preferably 5 to 10 parts by weight of Le A 36-132-Foreign polyalkylene terephthalate, preferably polyethylene terephthalate, in particular having an intrinsic viscosity IV of 50.8 cm3/g, C) 1 to 20 parts by weight, preferably 2 to 15 parts by weight, in particular 3 to 12 parts by weight, most preferably 5 to 10 parts by weight of a graft (co)polymer having a core-shell morphology, consisting of 10 to 90 wt.%, preferably 30 to 80 wt.%, in particular 50 to 80 wt.% (relative to the graft (co)polymer) of a particulate polymer having a glass transition temperature below 0 C, preferably below -20 C, in particular below -40 C as graft base and 90 to 10, preferably 70 to 20, in particular 50 to 20 wt.% (relative to the graft (co)polymer) of vinyl monomers as graft monomers, the graft monomers containing a proportion of at least 20 wt.%, preferably at least 50 wt.%, in particular at least 75 wt.%, (relative to the graft monomers), of acrylate monomers, D) 2 to 20 parts by weight, preferably 5 to 15 parts by weight, particularly preferably 7 to 15 parts by weight, most preferably 10 to 15 parts by weight of an oligomeric organic phosphoric acid ester, in particular one based on bisphenol A, E) 0 to 1 part by weight, preferably 0.1 to 0.5 parts by weight, in particular 0.2 to 0.5 parts by weight of fluorinated polyolefin, the sum of the parts by weight of all components being 100.
The compositions according to the invention particularly preferably contain no halogen-containing compounds such as aromatic polycarbonates or epoxy resins based on halogenated bisphenols, for example.

Component A

Le A 36-132-Foreign Aromatic polycarbonates and/or aromatic polyester carbonates in accordance with component A that are suitable according to the invention are known from the literature or can be prepared by methods known from the literature (for the preparation of aromatic polycarbonates see for example Schnell, "Chemistry and Physics of Polycarbonates", Interscience Publishers, 1964 and DE-AS 1 495 626, DE-A 2 232 877, DE-A 2 703 376, DE-A 2 714 544, DE-A 3 000 610, DE-A 3 832 396; for the preparation of aromatic polyester carbonates e.g. DE-A 3 077 934).
Aromatic polycarbonates are prepared for example by melt processes or by reacting diphenols with carbonic acid halides, preferably phosgene, and/or with aromatic dicarboxylic acid dihalides, preferably benzenedicarboxylic acid dihalides, by the interfacial polycondensation process, optionally using chain terminators, for example monophenols, and optionally using trifunctional or higher-functional branching agents, for example triphenols or tetraphenols.

Diphenols for the preparation of the aromatic polycarbonates and/or aromatic polyester carbonates are preferably those having the formula (I) (B)x (B)x OH
HO & A \ / (I), P
wherein A is a single bond, C1 to C5 alkylene, C2 to C5 alkylidene, C5 to C6 cycloalkylidene, -0-, -SO-, -CO-, -S-, -SO2-, C6 to C12 arylene, to which other aromatic rings optionally containing heteroatoms can be condensed, or a radical having the formula (II) or (III) Le A 36-132-Foreign (X

/ \ 6 (II) R R

_C / \ CH3 -CH3 1 (III) B is C1 to C12 alkyl, preferably methyl, x is mutually independently 0, 1 or 2, p is l or 0, and R5 and R6 can be individually selected for each X1 and mutually independently denote hydrogen or C1 to C6 alkyl, preferably hydrogen, methyl or ethyl, X1 denotes carbon and m denotes a whole number from 4 to 7, preferably 4 or 5, with the proviso that in at least one X1 atom R5 and R6 are both alkyl.

Preferred diphenols are hydroquinone, resorcinol, dihydroxydiphenols, bis(hydroxyphenyl)-C 1-C5-alkanes, bis(hydroxyphenyl)-C5-C6-cycloalkanes, bis(hydroxyphenyl) ethers, bis(hydroxyphenyl) sulfoxides, bis(hydroxyphenyl) ketones, bis(hydroxyphenyl) sulfones and u,a-bis(hydroxyphenyl) diisopropyl benzenes.

Le A 36-132-Foreign Particularly preferred diphenols are 4,4'-dihydroxydiphenyl, bisphenol A, 2,4-bis-(4-hydroxyphenyl)-2-methyl butane, 1,1-bis-(4-hydroxyphenyl) cyclohexane, 1,1-bis-(4-hydroxyphenyl)-3.3.5-trimethyl cyclohexane, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfone. 2,2-Bis-(4-hydroxyphenyl) propane (bisphenol A) is particularly preferred.

The diphenols can be used individually or in any combination whatsoever. The diphenols are known from the literature or can be obtained by methods known from the literature.

Suitable chain terminators for the preparation of the thermoplastic, aromatic polycarbonates are for example phenol, p-chlorophenol, p-tert-butyl phenol, but also long-chain alkyl phenols such as 4-(1,3-tetramethyl butyl) phenol according to DE-A
2 842 005 or monoalkyl phenol or dialkyl phenols having a total of 8 to 20 carbon atoms in the alkyl substituents, such as 3,5-di-tert-butyl phenol, p-iso-octyl phenol, p-tert-octyl phenol, p-dodecyl phenol and 2-(3,5-dimethyl heptyl) phenol and 4-(3,5-dimethyl heptyl) phenol. The amount of chain terminators to be used is generally between 0.5 mol% and 10 mol%, relative to the molar sum of diphenols used in each case.

The thermoplastic, aromatic polycarbonates can be branched by known means, and preferably by the incorporation of 0.05 to 2.0 mol%, relative to the sum of diphenols used, of trifunctional or higher-functional compounds, for example those having three or more phenolic groups.

Both homopolycarbonates and copolycarbonates are suitable. 1 to 25 wt.%, preferably 2.5 to 25 wt.%, relative to the total amount of diphenols to be used, of polydiorganosiloxanes having hydroxyaryloxy terminal groups can also be used in the production of copolycarbonates according to the invention in accordance with component A. These are known (US 3 419 634) and can be produced by methods Le A 36-132-Foreign known from the literature. The production of polydiorganosiloxane-containing copolycarbonates is described in DE-A 3 334 782.

In addition to the bisphenol A homopolycarbonates, preferred polycarbonates are the copolycarbonates of bisphenol A having up to 15 mol%, relative to the molar sums of diphenols, of other diphenols cited as being preferred or particularly preferred.
Aromatic dicarboxylic acid dihalides for the production of aromatic polyester carbonates are preferably the di-acid dichlorides of isophthalic acid, terephthalic acid, diphenyl ether-4,4'-dicarboxylic acid and naphthalene-2,6-dicarboxylic acid.
Mixtures of the di-acid dichlorides of isophthalic acid and terephthalic acid in a ratio of between 1:20 and 20:1 are particularly preferred.

In the production of polyester carbonates a carbonic acid halide, preferably phosgene, is additionally incorporated as a bifunctional acid derivative.

Examples of chain terminators for the production of aromatic polyester carbonates also include, in addition to the monophenols already cited, chloroformic acid esters thereof and the acid chlorides of aromatic monocarboxylic acids, which can optionally be substituted with Ci to C22 alkyl groups, along with aliphatic C2 to C22 monocarboxylic acid chlorides.

The quantity of chain terminators in each case is 0.1 to 10 mol%, relative to moles of diphenol in the case of phenolic chain terminators and to moles of dicarboxylic acid dichlorides in the case of monocarboxylic acid chloride chain terminators.

The aromatic polyester carbonates can also contain incorporated aromatic hydroxycarboxylic acids.

Le A 36-132-Foreign The aromatic polyester carbonates can be both linear and branched by known means (see DE-A 2 940 024 and DE-A 3 007 934 in this connection).

Examples of branching agents that can be used include trifunctional or polyfunctional carboxylic acid chlorides, such as trimesic acid trichloride, cyanuric acid trichloride, 3,3'-,4,4'-benzophenone tetracarboxylic acid tetrachloride, 1,4,5,8-naphthalene tetracarboxylic acid tetrachloride or pyromellitic acid tetrachloride, in quantities of 0.01 to 1.0 mol% (relative to dicarboxylic acid dichlorides used) or trifunctional or polyfunctional phenols, such as phloroglucinol, 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl) heptene-2,4,4-dimethyl-2,4,6-tri-(4-hydroxyphenyl) heptane, 1,3,5-tri-(4-hydroxyphenyl) benzene, 1,1,1-tri-(4-hydroxyphenyl) ethane, tri-(4-hydroxyphenyl) phenyl methane, 2,2-bis-[4,4-bis-(4-hydroxyphenyl) cyclohexyl]
propane, 2,4-bis-(4-hydroxyphenyl isopropyl) phenol, tetra-(4-hydroxyphenyl) methane, 2,6-bis-(2-hydroxy-5-methylbenzyl)-4-methyl phenol, 2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl) propane, tetra-(4-[4-hydroxyphenyl isopropyl] phenoxy) methane, 1,4-bis-[4,4'-dihydroxytriphenyl) methyl]
benzene, in quantities of 0.01 to 1.0 mol%, relative to diphenols used. Phenolic branching agents can be included with the diphenols, acid chloride branching agents can be introduced together with the acid dichlorides.

The proportion of carbonate structural units in the thermoplastic, aromatic polyester carbonates can be varied as required. The proportion of carbonate groups is preferably up to 100 mol%, in particular up to 80 mol%, particularly preferably up to 50 mol%, relative to the sum of ester groups and carbonate groups. Both the ester and the carbonate component of the aromatic polyester carbonates can be in the form of blocks or randomly distributed in the polycondensate.

The thermoplastic, aromatic poly(ester)carbonates have average weight-average molecular weights (M,,, measured by gel permeation chromatography) of >_25,000, preferably >_ 26,000. Poly(ester)carbonates having a weight-average molecular Le A 36-132-Foreign weight of up to 35,000, preferably up to 32,000, particularly preferably up to 30,000 g/mol are preferably used according to the present invention.

The thermoplastic, aromatic poly(ester)carbonates can be used alone or in any combination.

Component B

The polyalkylene terephthalates according to component B are reaction products of aromatic dicarboxylic acids or reactive derivatives thereof, such as dimethyl esters or anhydrides, and aliphatic, cycloaliphatic or araliphatic diols and mixtures of these reaction products.

Preferred polyalkylene terephthalates contain at least 80 wt.%, preferably at least 90 wt.%, relative to the dicarboxylic acid component, of terephthalic acid radicals and at least 80 wt.%, preferably at least 90 mol%, relative to the diol component, of ethylene glycol and/or butanediol-1,4 radicals.

In addition to terephthalic acid radicals, the preferred polyalkylene terephthalates can contain up to 20 mol%, preferably up to 10 mol%, of radicals of other aromatic or cycloaliphatic dicarboxylic acids having 8 to 14 C atoms or aliphatic dicarboxylic acids having 4 to 12 C atoms, such as radicals of phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, 4,4'-diphenyl dicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, cyclohexane diacetic acid.

In addition to ethylene glycol or butanediol-1,4 radicals, the preferred polyalkylene terephthalates can contain up to 20 mol%, preferably up to 10 mol%, of other aliphatic diols having 3 to 12 C atoms or cycloaliphatic diols having 6 to 21 C
atoms, e.g. radicals of propanediol-1,3, 2-ethyl propanediol-1,3, neopentyl glycol, pentanediol-1,5, hexanediol-1,6, cyclohexane dimethanol-1,4, 3-ethyl pentanediol-2,4, 2-methyl pentanediol-2,4, 2,2,4-trimethyl pentanediol-1,3, 2-ethyl hexanediol-Le A 36-132-Foreign 1,3, 2,2-diethyl propanediol-1,3, hexanediol-2,5, 1,4-di-(P-hydroxyethoxy)benzene, 2,2-bis-(4-hydroxycyclohexyl) propane, 2,4-dihydroxy- 1, 1,3,3 -tetramethyl cyclobutane, 2,2-bis-(4-(3-hydroxyethoxyphenyl) propane and 2,2-bis-(4-hydroxypropoxyphenyl) propane (DE-A 2 407 674, 2 407 776, 2 715 932).

The polyalkylene terephthalates can be branched by incorporating relatively small amounts of trihydric or tetrahydric alcohols or tribasic or tetrabasic carboxylic acids, e.g. according to DE-A 1 900 270 and US-PS 3 692 744. Examples of preferred branching agents are trimesic acid, trimellitic acid, trimethylol ethane and propane and pentaerythritol.

Polyethylene terephthalates and/or polybutylene terephthalate are particularly preferred, polyethylene terephthalate being preferred in particular.
Polyalkylene terephthalates having a high tendency to crystallise are particularly preferably used.

These are characterised in that the isothermal crystallisation time determined by the method cited in the example part is preferably < 20 min, particularly preferably < 10 min, in particular < 7 min.

The polyalkylene terephthalates preferably have an intrinsic viscosity measured in phenol/o-dichlorobenzene (1:1 parts by weight) at 25 C in an Ubbelohde viscometer of <_0.8 cm3/g; the intrinsic viscosity of the polyalkylene terephthalates is generally greater than 0.3, in particular greater than 0.4 cm3/g.

The polyalkylene terephthalates can be produced by known methods (e.g.
Kunststoff-Handbuch, Volume VIII, page 695 ff., Carl-Hanser-Verlag, Munich 1973).

Component C

Suitable graft bases C.1 for the graft polymers having a core-shell structure C are for example diene rubbers, EP(D)M rubbers, i.e. those based on ethylene/propylene and Le A 36-132-Foreign optionally diene compounds, also acrylate, polyurethane, silicone, chloroprene and ethylene/vinyl acetate rubbers, as well as silicone-acrylate composite rubbers.

Diene rubbers, silicone rubbers and silicone-acrylate composite rubbers are preferred. Silicone-acrylate composite rubbers are particularly preferred.

Rubbers that are preferably suitable as graft base C.1 are diene rubbers, e.g.
those based on butadiene or isoprene, or mixtures of diene rubbers or copolymers of diene rubbers or mixtures thereof with other copolymerisable monomers. Preferred copolymerisable monomers are vinyl monomers selected from the group of vinyl aromatics, ring-substituted vinyl aromatics (such as e.g. styrene, a-methyl styrene, p-methyl styrene), methacrylic acid (C1-C8) alkyl esters, (such as methyl methacrylate, ethyl methacrylate), acrylic acid (C1-Cg) alkyl esters (such as n-butyl acrylate and tert-butyl acrylate or mixtures thereof), vinyl cyanides (unsaturated nitriles such as acrylonitrile and methacrylonitrile) and derivatives of unsaturated carboxylic acids such as anhydrides and imides (for example maleic anhydride and N-phenyl maleinimide).

Pure polybutadiene rubber is particularly preferred.
These graft bases generally have an average particle size (d50 value) of 0.05 to 5 m, preferably 0.1 to 2 m, in particular 0.1 to 1 gm.

The average particle size d50 is the diameter above and below which respectively 50 wt.% of the particles lie. It can be determined by ultracentrifuge measurement (W. Scholtan, H. Lange, Kolloid, Z. and Z. Polymere 250 (1972), 782-1796).

The gel content of these graft bases is at least 30 wt.%, preferably at least 40 wt.%
(measured in toluene).

The gel content is determined at 25 C in a suitable solvent (M. Hoffmann, H.
Kromer, R. Kuhn, Polymeranalytik I and II, Georg Thieme-Verlag, Stuttgart 1977).
Particularly preferably suitable as graft base C.1 for the graft polymers having a core-shell structure C are those acrylate rubbers, silicone rubbers or silicone-acrylate composite rubbers containing 0 to 100 wt.%, preferably 1 to 99 wt.%, in particular to 99 wt.%, particularly preferably 30 to 99 wt.% of polyorganosiloxane component and 100 to 0 wt.% , preferably 99 to 1 wt.%, in particular 90 to 1 wt.%, particularly preferably 70 to 1 wt.% of polyalkyl (meth)acrylate rubber component 10 (the total amount of the individual rubber components adding up to 100 wt.%).

Such rubbers preferably have an average particle diameter of 0.01 to 0.6 gm.
Silicone-acrylate rubbers that are preferably used are those whose production is described in JP 08 259 791-A, JP 07 316 409-A and EP-A 0 315 035.

The polyorganosiloxane component in the silicone-acrylate composite rubber can be produced by reacting an organosiloxane and a multifunctional crosslinking agent in an emulsion polymerisation process. It is also possible to introduce graft-active sites into the rubber by the addition of suitable unsaturated organosiloxanes.

The organosiloxane is generally cyclic, the ring structures preferably containing 3 to 6. Si atoms. Hexamethyl cyclotrisiloxane, octamethyl cyclotetrasiloxane, decamethyl cyclopentasiloxane, dodecamethyl cyclohexasiloxane, trimethyl triphenyl cyclotrisiloxane, tetramethyl tetraphenyl cyclotetrasiloxane, octaphenyl cyclotetrasiloxane, which can be used alone or in a blend of two or more compounds, are cited by way of example. The organosiloxane component should be included in the structure of the silicone component in the silicone-acrylate rubber in a proportion of at least 50 wt.%, preferably at least 70 wt.%, relative to the silicone proportion in the silicone-acrylate rubber.

Le A 36-132-Foreign Trifunctional or tetrafunctional silane compounds are generally used as crosslinking agent. The following are cited by way of example as being particularly preferred:
trimethoxymethyl silane, triethoxyphenyl silane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetrabutoxysilane. The amount of branching agent is generally 0 to 30 wt.% (relative to the polyorganosiloxane component in the silicone-acrylate rubber).

Compounds forming one of the following structures are preferably used to incorporate graft-active sites into the polyorganosiloxane component of the silicone-acrylate rubber:

CHFC-COO-- (CH2--SIRS nO(3_n)/2 (GI-1) R
CH7_1 \ SIRS nO(3-n),2 (GI-2) Rs CH2=CH-SiR5 nO(3-n)/2 (GI-3) HS+CH2) SiR5 nO(3_r,),2 (GI-4) wherein R5 denotes methyl, ethyl, propyl or phenyl, R6 denotes hydrogen or methyl, Le A 36-132-Foreign n denotes 0, 1 or 2 and p denotes a number from 1 to 6.

(Meth)acryloyloxysilane is a preferred compound for forming the structure (GI
1).
Preferred (meth)acryloyloxysilanes are for example /3-methacryloyloxyethyl dimethoxymethyl silane, -y-methacryloyloxypropyl methoxydimethyl silane, 'y-methacryloyloxypropyl dimethoxymethyl silane, ymethacryloyloxypropyl trimethoxysilane, -y-methacryloyloxypropyl ethoxydiethyl silane, y-methacryloyloxypropyl diethoxymethyl silane, 'y-methacryloyloxybutyl diethoxymethyl silane.

Vinyl siloxanes, in particular tetramethyl tetravinyl cyclotetrasiloxane, are capable of forming the structure GI-2.

p-Vinylphenyl dimethoxymethyl silane, for example, can form structure GI-3. 'y-Mercaptopropyl dimethoxymethyl silane, 'y-mercaptopropyl methoxydimethyl silane, ,y-mercaptopropyl diethoxymethyl silane, etc., can form structure (GI-4).

The amount of these compounds is 0 to 10, preferably 0.5 to 5 wt.% (relative to the polyorganosiloxane component).

The acrylate component in the silicone-acrylate composite rubber can be produced from alkyl (meth)acrylates, crosslinking agents and graft-active monomer units.

Preferred alkyl (meth)acrylates that are cited by way of example are alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, ethylhexyl acrylate and alkyl methacrylates such as hexyl methacrylate, 2-ethylhexyl methacrylate, n-lauryl methacrylate and particularly preferably n-butyl acrylate.

Le A 36-132-Foreign Multifunctional compounds can be used as crosslinking agents. Examples thereof that are cited by way of example are: ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate and 1,4-butylene glycol dimethacrylate.

The following compounds for example, alone or in combination, can be used to introduce graft-active sites: allyl methacrylate, triallyl cyanurate, triallyl isocyanurate, allyl methacrylate. Allyl methacrylate can also act as a crosslinking agent. These compounds are used in quantities of 0.1 to 20 wt.%, relative to the acrylate rubber component in the silicone-acrylate composite rubber.

Methods for producing the silicone-acrylate composite rubbers preferably used in the compositions according to the invention, as well as the grafting thereof with monomers, are described for example in US-A 4 888 388, JP 08 259 791 A2, JP 07 316 409A and EP-A 0 315 035. Suitable graft bases C.1 for the graft polymer C
are both those silicone-acrylate composite rubbers whose silicone and acrylate components form a core-shell structure and those which form a network in which the acrylate and silicone components are completely interpenetrated (interpenetrating network).

The graft polymerisation onto the graft bases described above can be performed in suspension, dispersion or emulsion. Continuous or discontinuous emulsion polymerisation is preferred. This graft polymerisation is performed with radical initiators (e.g. peroxides, azo compounds, hydroperoxides, persulfates, perphosphates) and optionally using anionic emulsifiers, e.g. carboxonium salts, sulfonic acid salts or organic sulfates. Graft polymers having high graft yields, i.e. a large proportion of the polymer in the graft monomers is chemically bonded to the rubber, are formed in this way.

Mixtures of Le A 36-132-Foreign C.2.1 0 to 80 wt.%, preferably 0 to 50 wt.%, in particular 0 to 25 wt.%
(relative to the graft shell) of vinyl aromatics or ring-substituted vinyl aromatics (such as e.g. styrene, a-methyl styrene, p-methyl styrene), vinyl cyanides (unsaturated nitriles such as acrylonitrile and methacrylonitrile) and C.2.2 100 to 20 wt.%, preferably 100 to 50 wt.%, in particular 100 to 75 wt.%
(relative to the graft shell) of monomers selected from the group comprising (meth)acrylic acid (C1-C8) alkyl esters (such as methyl methacrylate, n-butyl acrylate, t-butyl acrylate) and derivatives (such as anhydrides and imides) of unsaturated carboxylic acids (such as maleic anhydride and N-phenyl maleinimide) are preferably used to constitute the graft shell C.2.

The graft shell particularly preferably consists of one or a mixture of several pure (meth)acrylic acid (C1-C8) alkyl esters, in particular of pure methyl methacrylate.
Component D

Oligomeric phosphoric or phosphonic acid esters having the general formula (IV) O O
R'(O)- IP O-X-O-`P (O)- R4 IV
(O)õ (O) 12 n R R3 q wherein R1, R2, R3 and R4 mutually independently denote C1 to C8 alkyl, C5 to C6 cycloalkyl optionally substituted with alkyl, preferably C1 to C4 alkyl, C6 to C20 aryl or C7 to C12 aralkyl, Le A 36-132-Foreign n mutually independently denotes 0 or 1 q denotes 0.5 to 30 and X denotes a mononuclear or polynuclear aromatic radical having 6 to 30 C
atoms, or a linear or branched aliphatic radical having 2 to 30 C atoms, which can be OH-substituted and can contain up to 8 ether bonds, are preferably used as fire retardants.
R1, R2, R3 and R4 preferably mutually independently stand for C1 to C4 alkyl, phenyl, naphthyl or phenyl C1-C4 alkyl. The aromatic groups R1, R2, R3 and R4 can for their part be substituted with alkyl groups, preferably C1-C4 alkyl. Particularly preferred aryl radicals are cresyl, phenyl, xylenyl, propyl phenyl or butyl phenyl.

X in formula (IV) preferably denotes a mononuclear or polynuclear aromatic radical having 6 to 30 C atoms. This is preferably derived from diphenols having formula (I).

n in formula (IV) can mutually independently be 0 or 1, n preferably equalling 1.

q stands for values from 0.5 to 30, preferably 0.8 to 15, particularly preferably 1 to 5, in particular 1 to 2.

X particularly preferably stands for Le A 36-132-Foreign / :~' CN3 / CH/

CH

in particular X is derived from resorcinol, hydroquinone, bisphenol A or diphenyl phenol. X is particularly preferably derived from bisphenol A.

Other preferred phosphorus-containing compounds are compounds having the formula (IVa) 0 (R5) (R5)m R 1--(0)-._pl mY ~~ 0) 4 Na (0)~ (0)õ

q wherein R1, R2, R3, R4, n and q have the meaning specified in formula (IV), m mutually independently denotes 0, 1, 2, 3 or 4, R5 and R6 mutually independently denote C1 to C4 alkyl, preferably methyl or ethyl and Y denotes C1 to C7 alkylidene, C1 to C7 alkylene, C5 to C12 cycloalkylene, C5 to C12 cycloalkylidene, -0-. -S-. -SO2- or -CO-, preferably isopropylidene or methylene.

Le A 36-132-Foreign __O 1 -0 where q = 1 to 2, is particularly preferred.

The phosphorus compounds according to component C are known (cf. e.g. EP-A 0 363 608, EP-A 0 640 655) or can be produced by known methods in an analogous way (e.g. Ullmanns Enzyklopadie 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).

The average q values can be determined by determining the composition of the phosphate mixture (molecular weight distribution) by a suitable method (gas chromatography (GC), high-pressure liquid chromatography (HPLC), gel permeation chromatography (GPC)) and using it to calculate the average values for q.

Component E

The flame retardants corresponding to component D are often used in combination with so-called antidripping agents, which reduce the tendency of the material to drip as it bums in the event of a fire. Compounds from the substance classes comprising fluorinated polyolefins, silicones and aramid fibres are cited here by way of example.
These can also be used in the compositions according to the invention.
Fluorinated polyolefins are preferably used as antidripping agents.

Le A 36-132-Foreign Fluorinated polyolefins are known and described for example in EP-A 0 640 655.
They are sold by DuPont, for example, under the brand name Teflon 30N.

The fluorinated polyolefins can be used both in pure form and in the form of a coagulated mixture of emulsions of the fluorinated polyolefins with emulsions of the graft polymers (component B) or with an emulsion of a (co)polymer on a vinyl monomer basis, the fluorinated polyolefin being mixed as an emulsion with an emulsion of the graft polymer or the copolymer and then coagulated.

The fluorinated polyolefins can further be used as a pre-compound with the graft polymer (component B) or a copolymer, preferably on a vinyl monomer basis. The fluorinated polyolefins are mixed as a powder with a powder or pellets of the graft polymer or copolymer and melt compounded, generally at temperatures of 200 to 330 C, in conventional units such as internal mixers, extruders or twin screws.

The fluorinated polyolefins can also be used in the form of a masterbatch produced by emulsion polymerisation of at least one monoethylene-unsaturated monomer in the presence of an aqueous dispersion of the fluorinated polyolefin. Preferred monomer components are styrene, acrylonitrile, methyl methacrylate and mixtures thereof. The polymer is used as a free-flowing powder after acid precipitation and subsequent drying.

The coagulates, pre-compounds or masterbatches conventionally have solids contents of fluorinated polyolefin of 5 to 95 wt.%, preferably 7 to 80 wt.%.

The fluorinated polyolefins are used in concentrations of 0 to 1 part by weight, preferably 0.1 to 0.5 parts by weight, in particular 0.2 to 0.5 parts by weight, these quantities relating to the pure fluorinated polyolefin if a coagulate, pre-compound or masterbatch is used.

Le A 36-132-Foreign Component F (other additives) The compositions according to the invention can also contain up to 10 parts by weight, preferably 0.1 to 5 parts by weight, of at least one conventional polymer additive, such as a lubricant and release agent, for example pentaerythritol tetrastearate, a nucleating agent, an antistatic agent, a stabiliser, a light stabiliser, a filler and reinforcing agent, a dye or pigment and another flame retardant or a flame retardant synergist, for example an inorganic substance in nanoscale form and/or a silicate material such as talc or wollastonite.

All stated parts by weight in this application are standardised such that the sum of the parts by weight of all components in the composition is 100.

The compositions according to the invention are produced by mixing the various components by known means and melt compounding and melt extruding them in conventional units such as internal mixers, extruders and twin screws at temperatures from 200 C to 300 C.

The individual components can be mixed by known means both successively and simultaneously, both at around 20 C (room temperature) and at elevated temperature.

The compositions according to the invention can be used in the production of all types of moulded parts. These can be produced for example by injection moulding, extrusion and blow moulding processes. A further form of processing is the production of mouldings by thermoforming from prefabricated sheets or films.

Examples of such moulded parts are films, profiles, all types of housing parts, e.g.
for domestic appliances such as juice extractors, coffee machines, mixers; for office equipment such as monitors, printers, copiers; also plates, pipes, electrical wiring ducts, profiles for the construction sector, interior fittings and exterior applications;

Le A 36-132-Foreign CA 02494351 2005-01-26 parts for the electrical engineering sector such as switches and plugs, and interior and exterior automotive parts.

The compositions according to the invention can be used in particular to produce the following moulded parts, for example:

Interior fittings for rail vehicles, ships, aircraft, buses and cars, hub caps, housings for electrical appliances containing miniature transformers, housings for equipment for information dissemination and transfer, housings and cladding for medical purposes, massage equipment and housings, children's toy vehicles, two-dimensional wall panels, housings for safety equipment, rear spoilers, car body parts, heat-insulated transport containers, equipment for holding or caring for small animals, moulded parts for plumbing and bathroom equipment, cover grids for fan openings, moulded parts for garden sheds and tool sheds, housings for gardening equipment.

The examples below serve to illustrate the invention in more detail.

Le A 36-132-Foreign Examples The components set out in Table 1 and briefly described below were melt compounded on a ZSK-25 at 240 C. Unless otherwise specified, the specimens were produced on an Arburg 270 E injection moulding machine at 240 C.

Component Al Linear polycarbonate based on bisphenol A having a weight-average molecular weight (Mw) according to GPC of 28,000 g/mol.

Component A2 Linear polycarbonate based on bisphenol A having a weight-average molecular weight (Mw) according to GPC of 26,000 g/mol.

Component A3 Linear polycarbonate based on bisphenol A having a weight-average molecular weight (Mw) according to GPC of 23,000 g/mol.

Component A4 Linear polycarbonate based on bisphenol A having a weight-average molecular weight (Mw) according to GPC of 18,000 g/mol.

Component B
Polyethylene terephthalate Le A 36-132-Foreign This is a polyethylene terephthalate having an intrinsic viscosity IV of 0.74 cm3/g and an isothermal crystallisation time at 215 C of approx. 4.2 minutes.

The intrinsic viscosity is measured in phenol/o-dichlorobenzene (1:1 parts by weight) at 25 C.

The isothermal crystallisation time of PET is determined by the DSC method (differential scanning calorimetry) using a PERKIN ELMER DSC 7 Differential Scanning Calorimeter (weighed amount approx. 10 mg, perforated Al pan) with the following temperature programme:

1. Heating from 30 C to 290 C at 40 C/min, 2. 5 min isothermal at 290 C, 3. Cooling from 290 C to 215 C at 160 C/min 4. 30 min isothermal at 215 C (crystallisation temperature).
The analysis software is PE Thermal Analysis 4.00.
Component C 1 ABS graft polymer, produced by emulsion polymerisation, having a rubber content of 50 wt.% and an A:B:S ratio of 15:45:50 and an acrylonitrile:styrene ratio of 30:70.

Component C 2 Graft polymer of 84 parts by weight of a copolymer of styrene and acrylonitrile in the ratio 73:27 on 16 parts by weight of crosslinked polybutadiene rubber, produced by bulk polymerisation.

Component C 3 Paraloid EXL 2600: MBS (methyl methacrylate-grafted butadiene-styrene rubber, core-shell structure, with a glass transition temperature of -80 C) supplied by Rohm & Haas, Antwerp (Belgium)-Component C 4 Metablen S2001, methyl methacrylate-grafted silicone-butyl acrylate composite rubber, core-shell structure, supplied by Mitsubishi Rayon Co., Ltd., Tokyo (Japan).
Component D

Bisphenol A-based oligophosphate 0 - 4}o0 CFi3 0 q=1.1 Component E

Blendex 449, Teflori masterbatch comprising 50 wt.% of styrene-acrylonitrile copolymer and 50 wt.% of PTFE from GE Specialty Chemicals, Bergen op Zoom (Netherlands).

Component F1/F2 Pentaerythritol tetrastearate (PETS) (F1) Phosphite stabiliser (F2) The stress cracking behaviour (ESC behaviour) is tested on specimens measuring mm x 10 mm x 4 mm. A mixture of 60 vol.% toluene and 40 vol.% isopropanol is used as the test medium. The samples are pre-extended using an arc-shaped jig and the time to fracture failure in this medium determined as a function of the pre-extension. The maximum pre-extension at which no fracture failure occurs within 5 minutes is assessed.

The decline in ESC behaviour at elevated processing temperatures is assessed as follows: specimens measuring 80 mm x 10 mm x 4 mm are produced at 240 C and 300 C on an Arburg "'270'E injection moulding machine. The specimens are pre-extended with a flexural strain of 2.4 %, exposed at room temperature to a bath of rapeseed oil and the time to stress cracking failure determined in both cases.; The decline in ESC behaviour is calculated as (time to failure at 240 C - time to failure at 300 C) / (time to failure at 240 C).
The notched impact resistance ak is determined in accordance with ISO 180/1 A.
The elongation at break is determined in the tensile test according to ISO
527.
The fire behaviour was measured in accordance with UL Subj. 94.V on specimens measuring 127 mm x 12.7 mm x 1.5 mm.

The Vicat B heat resistance is determined in accordance with DIN 53 460 (ISO
306) on specimens measuring 80 mm x 10 mm x 4 mm.

Le A 36-132-Foreign To determine the weld line strength, the impact resistance is measured at the weld line of specimens gated on both sides and measuring 170 x 10 x 4 mm in accordance with ISO 179/lU.

The melt viscosity is determined in accordance with DIN 54 811 at 260 C and at a shear rate of 1000 s"l.

A summary of the properties of the composition according to the invention and of the specimens obtained from it is set out in Table 1.

Le A 36-132-Foreign Table 1: Moulding compositions and their properties 1 Cl C2 2 3 C3 C4 4 5 C5 C6 Components [parts by wt.) Al (PCI) - - - - 70.0 - - - - -A2 (PC2) 70.0 70.0 70.0 70.0 - - - 72.0 67.0 62.0 57.0 A3 (PC3) - - - - - 70.0 - - - - -A4 (PC4) - - - - - - 70.0 - - - -B (PET) 7.0 7.0 7.0 7.0 7.0 7.0 7.0 5.0 10.0 15.0 20.0 Cl (emulsion - 9.0 - - - - - - - - -ABS) C2 (bulk ABS) - - 9.0 - - - - - - - -C3 (MBS) - - - 9.0 - - - - - - -C4 (Metablen 9.0 - - - 9.0 9.0 9.0 9.0 9.0 9.0 9.0 S2001) D (BDP) 12.5 12.5 12.5 12.5 12.5 12.5 12.5 12.5 12.5 12.5 12.5 E (Blendex 449) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 F1 (PETS) 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 F2 (phosphite 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 stabiliser) Properties Notched impact 55 15 8 43 55 48 8 57 43 12 10 resistance [kJ/m2]
VicatB 120 103 102 105 101 103 102 101 102 100 99 98 [ C]
Melt viscosity 211 267 192 236 223 168 91 209 184 167 148 (260 C/1000s') [Pas]
ESC behaviour >3.2 >3.2 >3.2 >3.2 >3.2 2.2 0.6 >3.2 >3.2 >3.2 >3.2 [%]
ESC reduction 63 79 - 56 - - - - - - -(240 C- 300 C) [%]

Le A 36-132-Foreign Elongation at 117 85 21 121 117 92 28 116 122 115 35 break [%]
Weld line 24 11 7 42 28 20 14 32 20 19 16 strength [kJ/m2]
UL94 V test at V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-1 V-1 1.5 mm C = comparison n.f. = no fracture It can be seen from Table 1 that:

1.) Only the moulding compositions containing as graft polymer one with an MMA-containing shell have an adequate notched impact resistance, weld line strength, elongation at break and processing stability (measured by the ESC reduction at high processing temperatures).

2.) Where polycarbonates having a low average molecular weight are used, the melt flowability naturally improves, but the notched impact resistance, ESC
behaviour, elongation at break and weld line strength deteriorate. Where polycarbonates having a weight-average molecular weight < 25,000 g/mol are used, these mechanical properties no longer satisfy the requirements of the intended areas of application.

3.) As the PET/PC ratio increases, the notched impact resistance, elongation at break, weld line strength, heat resistance and above all the flame resistance reduce. On the other hand, with a constant chemical resistance the melt flowability increases. PET contents of 5 to 10 wt.% have therefore proved to be particularly favourable.

Claims (17)

CLAIMS:

1. A composition containing:

(A) 40 to 90 parts by weight of an aromatic polycarbonate, an aromatic polyestercarbonate or a mixture thereof having a weight-average molecular weight, M w of 25,000 to 35,000 g/mol;

(B) 0.5 to 15 parts by weight of a polyalkylene terephthalate which has an intrinsic viscosity of <= 0.8 cm3/g;

(C) 1 to 20 parts by weight of a graft (co)polymer having a core-shell morphology, consisting of 10 to 90 wt.%, relative to the graft (co)polymer, of a graft base having a glass transition temperature below 0°C and 90 to 10 wt.%, relative to the graft (co)polymer, of graft monomers selected from at least one monomer of the group consisting of a vinyl aromatic, a ring-substituted vinyl aromatic, a (meth)acrylic acid (C1-C8) alkyl ester, a vinyl cyanide and a derivative of an unsaturated carboxylic acid, the graft monomers containing a proportion of at least 20 wt.%, relative to the graft monomers, of an acrylate monomer;

(D) 2 to 20 parts by weight of an oligomeric organic phosphoric or phosphinic acid ester; and (E) 0 to 1 part by weight of a fluorinated polyolefin, the sum of the parts by weight of all components being 100.

2. The composition according to claim 1, wherein (A) has a M w of 26,000 to 35,000 g/mol.

3. The composition according to claim 1 or 2, wherein the graft base is selected from at least one of the group consisting of a diene rubber, a copolymer of a diene rubber, a EP(D)M rubber, an acrylate rubber and a silicone-acrylate composite rubber.

4. The composition according to any one of claims 1 to 3, wherein the proportion of the acrylate monomer as the graft monomer is at least 50 wt.%.

5. The composition according to claim 4, wherein the proportion of the acrylate monomer as the graft monomer is at least 75 wt.%.

6. The composition according to any one of claims 1 to 5, wherein (D) has the general formula (IV):

wherein:

R1, R2, R3 and R4 mutually independently denote C1 to C8 alkyl, C5 to C6 cycloalkyl optionally substituted with alkyl, C6 to C20 aryl or C7 to C12 aralkyl;

n mutually independently denotes 0 or 1;
q denotes 0.5 to 30; and X denotes (i) a mononuclear or polynuclear aromatic radical having 6 to 30 C atoms, or (ii) a linear or branched aliphatic radical having 2 to 30 C
atoms, optionally OH-substituted and optionally containing up to 8 ether bonds.

7. The composition according to claim 6, wherein q denotes 1 to 5.

8. The composition according to claim 7, wherein q denotes 1 to 2.

9. The composition according to any one of claims 6 to 8, wherein X is:

10. The composition according to claim 9, wherein X is derived from hydroquinone, resorcinol or bisphenol A.

11. The composition according to any one of claims 1 to 10, containing:
50 to 80 parts by weight of (A);

1 to 10 parts by weight of (C), and 2 to 15 parts by weight of (D).

12. The composition according to any one of claims 1 to 11, containing 5 to 10 parts by weight of (B).

13. The composition according to any one of claims 1 to 12, wherein (B) is polyethylene terephthalate.

14. The composition according to any one of claims 1 to 13, containing a further additive selected from at least one of the group consisting of a lubricant, a release agent, a nucleating agent, an antistatic agent, a stabiliser, a light stabiliser, a dye, a pigment, a filler, a reinforcing agent, a flame retardant differing from (D) and a flame retardant synergist.

15. A process for producing the composition according to claim 1, wherein the components are mixed together and melt compounded or melt extruded at an elevated temperature.

16. Use of the composition according to any one of claims 1 to 14, for the production of a moulded part.

17. A moulded part obtained from the composition according to any one of claims 1 to 14.