MX2008007200A - Polycarbonate molding compositions - Google Patents

Abstract

The invention relates to thermoplastic compositions comprising A) from 10 to 90 parts by weight of aromatic polycarbonate and/or polyester carbonate, B) from 10 to 90 parts by weight of a rubber-modified graft polymer (B.1) or of a precompound composed of rubber-modified graft polymer (B.1) with a (co)polymer (B.2), or a mixture of a (co)polymer (B.2) with at least one polymer selected from the group of the rubber-modified graft polymers (B.1) and the precompounds composed of rubber-modified graft polymer with a (co)polymer (B.2) and C) from 0.005 to 0.15 part by weight, based on 100 parts by weight of the sum of components A and B, of at least one aliphatic and/or aromatic organic carboxylic acid, wherein component C is mixed into the melt comprising components A and B, or wherein first, in a first step, component B is premixed with component C and then, in a second step, the resulting mixture of B and C is mixed with a melt comprising component A. The invention further provides a process for producing the molding compositions and their use for producing moldings. The inventive molding compositions feature improved processing stability.

Description

COMPOSITIONS OF POLYCARBONATE MOLDING Description of the Invention The invention relates to thermoplastic compositions with improved processing stability containing polycarbonate and modified graft polymer of rubber and / or (co) vinyl polymer, a process for the production of these and their uses for the production of articles. trained Thermoplastic molding compositions comprising polycarbonate and ABS polymers (acrylonitrile / butadiene / styrene) have been known for a long time, US3 130 177 A, for example, describes easily processable molding compositions comprising polycarbonates and grafted polymers of mixtures of acrylonitrile monomers and a vinyl hydrocarbon on polybutadiene . These molding compositions are distinguished by good tenacity both at room temperature and at low temperatures, good melt flow and high thermal resistance. A disadvantage of these molding compositions is that, to avoid the harmful effects on the polycarbonate and the deterioration of the application properties caused by manufacturing, processing or aging, it must not contain certain constituents, such as, eg, substances that REF..193203 they act as bases and certain inorganic metallic compounds particularly compounds with metals (transition) oxides, in significant quantities, since the high temperatures, such as those that typically occur during the production and processing of the molding compositions, and with prolonged exposure to a hot, humid atmosphere, these constituents generally decompose the polycarbonate catalytically. This degradation of the polycarbonate is usually expressed as damage to the properties of the molding compositions, particularly the mechanical characteristics such as ductility and elongation properties. As a result, the choice of possible substances that will use these compositions is severely limited. For example, only those ABS polymers that are free of impurities that act as bases can be used. However, ABS polymers which are not intended to be mixed with polycarbonates usually contain, as a result of their production, residual amounts of substances acting as bases, which are used as polymerization aids, eg in polymerization by emulsion or as auxiliary substances in the preparation process. In some cases, additives that act as bases are also added to ABS polymers deliberately (eg, lubricants and release agents). In addition, many commercially available polymer additives can not be used in compositions PC modified for impact, or can only be used with considerable costs for the properties of the compositions, since they act as bases or contain constituents / impurities as bases that result from their production. Examples of these additives may be molding release agents, antistatic agents, stabilizers, light stabilizers, flame retardants, and dyes. However, the use of metallic oxide compounds, eg, in the form of certain pigments (eg, titanium dioxide, iron oxide) and / or fillers and reinforcing materials (eg, talc, kaolin, etc.) usually cause considerable, undesirable losses of processing stability in the compositions. PC / ABS (polycarbonate / acrylonitrile / butadiene / styrene) compositions are known from US 4,299,929, which are characterized by the addition of inorganic acids, organic acids or organic acid anhydrides. The resulting molding compositions are distinguished by improved thermal stability. PC / ABS compositions with a combination of high toughness and good surface finish and, at the same time good thermal resistance and hardness of ball dentition, characterized in that a compound with a molecular weight of 150 to 260 is contained are known. g / mol having several carboxy groups The composition disclosed in EP-A 0576950 preferably contains from 50 to 100 parts by weight of ABS, 1 to 50 parts by weight of polycarbonate and 0.2 to 5 parts by weight of the compound containing various carboxyl groups. In EP-A 0683200, modified impact polycarbonate compositions containing an acid containing phosphorus and a phosphite are disclosed. The object on which the invention is based consists in improving the polycarbonate compositions modified for impact for the production of articles with complex shape, which are distinguished by an improved processing stability with good resistance to hydrolysis and a slightly natural shade. It has been found that impact modified polycarbonate compositions containing constituents that degrade polycarbonate under typical polycarbonate processing conditions exhibit improved processing stability with good resistance to hydrolysis and a slight natural staining (ie, yellowness index). YI) if certain acids are added in very small amounts. The acid according to component C is preferably selected such that it decomposes under the thermal conditions of formulation, volatile release compounds and / or compounds that provide a neutral reaction (ie, neither an acid nor a base remain in the polycarbonate composition as a decomposition product of component C). The present invention therefore provides thermoplastic molding compositions containing A) 10 to 90 parts by weight, preferably 40 to 80 parts by weight, especially 55 to 75 parts by weight, of aromatic polycarbonate and / or polyester carbonate, B) 10 to 90 parts by weight, preferably 20 to 60 parts by weight, especially 25 to 45 parts by weight, of a grafted polymer modified with rubber (Bl) or a previous compound of grafted polymer modified with rubber (Bl) with a (co) polymer (B.2), or a mixture of a (co) polymer (B.2) with at least one polymer selected from the group of grafted polymers modified with rubber (Bl) and the previous polymer compounds grafted modified with rubber with a (co) polymer (B 2), and C) 0.005 to 0.15 parts by weight, preferably from 0.01 to 0.15 parts by weight, especially from 0.015 to 0.13 parts by weight, based on 100 parts by weight of the sum of the components A and B of at least one organic aliphatic and / or aromatic carboxylic acid, wherein the component C is mixed in the melt of the components A and B or where, in a first step, the component B is previously mixed with component C and then, in a second step, the resulting mixture of B and C is mixed with a melt containing component A.

Component A Aromatic polycarbonates and / or aromatic polyester carbonates according to compound A which are suitable according to the invention are known from the literature or can be produced by processes known from the literature (for the production of aromatic polycarbonates, cf. ., eg, Schnell, "Chemistry and Physics of Polycarbonates", Interscience Publishers, 1964, as well as 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 and DE-A 3 832 396, for the production of aromatic polyester carbonates, eg DE-A 3 077 934). Aromatic polycarbonates are produced, for example, by reducing biphenols with carbonic acid halides, preferably phosgene, and / or with aromatic bicarboxylic acid dihalides, preferably benzenedicarboxylic acid dihalides, by the process of polycondensation with the optional use of chain terminators, eg, monophenols, and with the optional use of trifunctional or higher branching agents, eg, triphenols or tetraphenols. These can be produced by a melt polymerization process by reacting the biphenols with, for example, biphenyl carbonate.

Biphenols for the production of aromatic polycarbonates and / or aromatic polyester carbonates are preferably those of formula (I) wherein A is a single bond, alkylene Ci to C5, C2 to C2 alkylidene, C to C6 cycloalkylidene, -O-, -SO-, -CO-, -S-, - SO ~, arylene C6 to Ci, wherein other aromatic rings, optionally containing heteroatoms, or a radical of formula (II) or (III) may condense B is, in each case, C 1 to C 2 alkyl, preferably methyl, halogen, preferably chlorine and / or bromine x each is independently of the other 0, 1 or 2, p is 1 or 0 and R5 and R5 can be selected each X1 individually and are, independently of one another, hydrogen or Ci to C alkyl, preferably halogen, methyl, ethyl, X1 is carbon and m is an integer of 4 or 7, preferably 4 or 5, with the proviso that at least one atom of X1, R5 and R6 are both alkyl at the same time. Preferred biphenols are hydroquinone, resorcinol, dihydrobiphenols, bis- (hydroxyphenyl) alkanes C1-C5, bis- (hydroxyphenyl) cycloalkanes Cs-C6, bis- (hydroxyphenyl) ethers, sulfoxides of bis (hydroxyphenyl), ketones of bis (hydroxyphelem) , sulfones of bis (hydroxyphenyl) a, a-bis (hydrox: phenyl) dusopropylbenzenes, as well as the derivatives with brominated ring and / or chlorinated ring thereof. Particularly preferred bifenols are 4,4'-dihydroxybiphenyl, bisphenol A, 2, 4-b? S (4-hydroxyphenyl) -2-methylbutane, 1,1-b? S (4-hydroxyphenyl) cyclohexane, 1, l-bis (4-hydroxyphenyl) -3,3-trimethylcyclohexane, 4,4'-dihydroxybiphenyl sulfide, 4,4'-dihydroxybiphenylsulphone and the di- and tetra-brominated or chlorinated derivatives thereof, such as .ej., 2, 2-bis (3-chloro-4-hydroxyphenyl) ropano, 2,2-bis (3,5-bichloro-4-h? drox? phenyl) ropano or 2, 2-b? s ( 3, 5-dibromo-4-hydroxyphenyl) propane. Particularly preferred is 2,2- bis (4-hydroxyphenyl) propane (bisphenol A). The biphenols can be used individually or as mixtures. The biphenols are known from the literature or can be obtained by means of processes known from the literature. Chain terminators suitable for the production of the thermoplastic, aromatic polycarbonates are, for example, phenol, p-chlorophenol, p-tert-butylphenol or 2,4,6-tribromophenol, but also the long-chain alkylphenols, such as - [2- (2, 4, 4-triethylpentyl)] phenol, 4- (1, 3-tetramethylbutyl) phenol according to DE-A 2 842 005 or monoalkylphenol or dialkylphenols with a total of 8 to 20 carbon atoms carbon in the alkyl substituents, such as 3,5-di-tert-butylphenol, p-iso-octylphenol, p-tert-octylphenol, p-dodecylphenol and 2- (3,5-dimethylheptyl) phenol and 4- (3 , 5-dimethylheptyl) phenol. The amount of chain terminators that are generally used are between 0.5 mol% and 10 mol%, based on the molar amount of the biphenols used in each case. Thermoplastic, aromatic polycarbonates have on average weight average molecular weights (Mw measured eg by GPC, ultracentrifuge measurement or light scattering) of 10,000 to 200,000 g / mol, preferably 15,000 to 80,000 g / mol, particularly in the preferred 24,000 to 32,000 g / mol. Thermoplastic, aromatic polycarbonates can branching in the known manner, preferably incorporating 0.05 to 2.0 mole%, based on the sum of the used bifenols of trifunctional or compounds greater than trifunctional, eg, those with three or more phenolic groups. Both homopolycarbonates and copolycarbonates are suitable. To produce polycarboants according to the compound A according to the invention, it is also possible to use from 1 to 25% by weight, preferably from 2.5 to 25% by weight, based on the total amount of biphenols to be used, of polybiorganosiloxanes with groups hydroxyaryl terminals. These are known (US 3 419 634) and can be produced by processes known from the literature. The production of copolycarbonates containing polybiorganosiloxanes is described in DE-A 3 334 782. The preferred polycarbonates are, in addition to the homopolycarbonates of bisphenol A, the copolycarbonates of bisphenol A with up to 15 mol%, based on the molar sums of biphenols, of other mentioned biphenols are particularly preferred or are particularly preferred 2, 2-bis (3,5-dibromo-4-hydroxy phenyl) propane. The aromatic bicarboxylic acid dihalides for the production of aromatic polyester carbonates are preferably the diacid bichloride of isophthalic acid, terephthalic acid, biphenyl 4,4'-bicarboxylic acid and Naphthalene-2,6-dicarboxylic acid. Particularly preferred are mixtures of diacid dichloride of isophthalic acid and terephthalic acid with a ratio between 1:20 and 20: 1. In the production of the polyester carbonates, a halide of carbonic acid, preferably phosgene, is further incorporated as a bifunctional acid derivative. Chain terminators suitable for the production of the aromatic polyester carbonates are, in addition to monophenols already mentioned, their chlorocarbonates and the acid chlorides of aromatic monocarboxylic acids, which can optionally be substituted by the C-alkyl groups. to C? 2 or by halogen atoms, as well as chlorides of aliphatic monocarboxylic acids C? to C22. The amount of chain terminators is 0.1 to 10 % mol in each case, based on the case of phenolic chain terminators in moles of bi-phenol and in the case of chain terminators of monocarboxylic acid chloride in moles of bicarboxylic acid bichloride. The aromatic polyester carbonates may also contain incorporated aromatic hydroxycarboxylic acids.

The aromatic polyester carbonates can be linear or branched by a known method (DE-A 2 940 024 and DE-A 3 007 934).

Examples of branching agents which can be used are tri- or polyfunctional acyl chlorides, such as trimesic acid trichloride, cyanuric acid trichloride, 3,3'-, 4,4'-benzophenonetracarboxylic acid tetrachloride, acid tetrachloride 1, 4,5,8-naphthalenetetracarboxylic or pyromellitic acid tetrachloride, in amounts of 0.01 to 1.0 mol% (used based on dicarboxylic acid bichlorides) or tri-or polyfunctional phenols, such as fluoroglucinol, 4,6-dimethyl- 2, 4,6-tri (4-hydroxypheni 1) hept-2-ene, 4,6-dimethyl-2,4,6-tri- (4-hydroxy phenyl) heptane, 1, 3, 5-tri- ( 4-hydroxyphenyl) -benzene, 1, 1, 1-tri- (4-hydroxyphenyl) ethane, tri (4-hydroxyphenyl) phenylmethane, 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-methyl-benzyl) -4-methylphenol, 2- (4-hydroxyphenyl-2- (2, 4 -dihydroxy phenyl), tetrano (4- [4-hydroxy phenyl isopropyl] phenoxy) methane, 1,4-bis [4,4'-dihydroxytriphenyl) methyl] enne, in amounts of 0.01 to 1.0 mol% based on the used biphenols. Phenolic branching agents can occur with the biphenols; acid chloride branching agents can be added together with the acidic bichlorides. In aromatic polyester carbonates, thermoplastic, the proportion of carbonate structural units can vary at will. The proportion of the carbonate groups is preferably up to 100 mol%, especially up to 80 mol%, particularly preferably up to 50 mol% based on the sum of the ester groups and carbonate groups. Both ester and carbonate portions of the aromatic polyester carbonates may be present in block form or randomly distributed in the polycondensate. The relative viscosity of the solution (? Rel) of the aromatic polycarbonates and polyester carbonates is in the range of 1.18 to 1.4, preferably 1.2 to 1.32. (measured in 0.5 g polycarbonate or polyester carbonate solvents in 100 ml of methylene solution at 252C). The thermoplastic aromatic polycarbonates and polyester carbonates can be used individually or in any mixture.

Compound B Compound Bl comprises one or more polymers grafted from Bll from 5 to 95, preferably from 30 to 90% by weight, of at least one vinyl monomer at Bl2 95 to 5, preferably 70 to 10% by weight of one or more chains. main with glass transition temperatures of < 10 ° C, preferably < 0eC, particularly preferably < -202C.

The main chain B.l.2 usually has an average particle size (d50 value) of 0.05 to 10 μm, preferably 0.1 to 5 μ, particularly preferably 0.15 to 1 μ. Bll monomers Bll blends are preferred from 50 to 99 parts by weight vinyl aromatics and / or ring-substituted vinyl aromatics (such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene) and / or alkyl methacrylates. (Ci-Cß), such as methyl methacrylate, ethyl methacrylate, and Bl1.2 1 to 50 parts by weight of vinyl cyanides (unsaturated nitriles, such as acrylonitrile and methacrylonitrile) and / or alkyl (meth) acrylates (C 1 -Ci), such as methyl methacrylate, n-butyl acrylate, t-butyl acrylate, and / or derivatives ( such as anhydrides and imides) of unsaturated carboxylic acids, e.g., maleic anhydride and N-phenylmaleimide. Preferred monomers B.l.1.1 are selected from at least one of monomers of styrene, α-methylstyrene and methyl methacrylate; the preferred monomers B.l.1.2 are selected from at least one of the monomers of acrylonitrile, maleic anhydride, and methyl methacrylate. Particularly preferred monomers are B.l.1.1 styrene and B.l.1.2 acplonitplo. The suitable main chains B.1.2 for the grafted polymers Bl are, for example, diene rubbers, EP (D) M rubbers, ie those based on ethylene / propylene and optionally diene, acrylate, polyurethane, silicone, chloroprene and ethylene / vmyl acetate rubbers as well as rubbers composed of sil cona / acrr lato. Preferred main chains Bl2 are diene rubbers, eg, based on butadiene and isoprene or mixtures of diene rubbers or copolymer of diene rubbers or mixtures of these with other polymerizable monomers (eg, in accordance with Bl 1.1 and Bl1.2), provided that the vitreous transition temperature of component B.2., Is less than < 102C, preferably < 0SC, particularly preferably < -202C. The pure polybutadiene rubber is particularly preferred. Particularly preferred polymers Bl are, for example, ABS polymers (emulsion, bulk ABS and suspension), as described, for example, in DE-OS 2 035 390 (US-PS 3 644 574) or in DE- OS 2 248 242 (= GB-PS 1 409 275) and in Ullmanns, Enzyklopadie der Technischen Chemie, vol. 19 (1980), pp. 280 ff. The gel content of the main chain B.l.2 is at least 30% by weight, preferably at least 40% by weight (measured in toluene).

The B.l. grafted copolymers are produced by free radical polymerization, eg, by emulsion, suspension, solution or bulk polymerization, preferably by emulsion or bulk polymerization, particularly preferably by emulsion polymerization. Suitable graft rubbers are also polymers produced by redox initiation with an initiator system comprising organic hydroperoxide and ascorbic acid according to US Pat. No. 4,937,285. Because it is known that grafted monomers are not necessarily grafted onto the backbone completely during the grafting reaction, the grafted polymers Bl according to the invention are also projected to mean those products obtained by (co) polymerization of the grafted monomers in the presence of the main chain and also the formation during the preparation. Suitable acrylate rubbers according to B.l.2 are preferably alkyl acrylate polymers, optionally with up to 40% by weight, base in B.l.2 of other polymerizable ethylenically unsaturated monomers. Preferred polymerizable acrylates include C, to C8 alkyl esters, e.g., methyl, ethyl, butyl, n-octyl and 2-ethylhexyl esters; esters of halogen alkyl, preferably halogen alkyl CI-CB esters, such as chloroethyl acrylate, and mixtures of these monomers. For crosslinking purposes, the monomers can be polymerized with more than one polymerizable double bond. Preferred examples of crosslinking monomers are the esters of unsaturated monocarboxylic acids with 3 to 8 carbon atoms and unsaturated monohydric alcohols with 3 to 12 carbon atoms, or more saturated polyols with 2 to 4 OH groups and 2 to 20 carbon atoms, such as ethylene glycol dimethacrylate, iron methacrylate; polyunsaturated heterocyclic compounds, such as trivinyl cyanurate and triallyl; polyfunctional vmyl compounds, such as di- and trivinylbenzenes; but also triallyl phosphate and diallyl phosphate. Preferred crosslinking monomers are allyl metacrate, ethylene glycol dimethacrylate, diallyl phthalate and heterocyclic compounds containing at least three ethymethically unsaturated groups. Particularly preferred crosslinking monomers are the cyclic monomers of triallyl cyanurate, triallyl isocyanurate, tpacploylhexahydro-s-triazm and tpalyl benzones. The amount of crosslinked monomers is preferably 0.02 to 5, especially 0.05 to 2% by weight, based on the main chain B.l.2. In the case of cyclic crosslinking monomers with at least three ethylenically unsaturated groups, it is advantageous to limit the amount to less than 1% by weight of the main chain B.l.2.

"Other preferred polymerizable ethylenically unsaturated monomers, which may optionally be used in addition to the acrylates to produce the main chain of Bl2, are eg, acrylonitrile, styrene, α-methylstyrene, acrylamides, vinyl-C este alkyl esters. C6, methyl methacrylate, butadiene. Preferred acrylate rubbers as the main chain B.2 are emulsion polymers having a gel content of at least 60% by weight. Other suitable main chains according to Bl2 are silicone rubbers with active grafting points, as described in DE-OS 3 704 657, DE-OS 3 704 655, DE-OS 3 631 540 and DE-OS 3 631 53 . The gel content of the main chain B.l.2 is determined in a suitable solvent at 25 eC (M. Hoffmann, H. Krómer, R. Kuhn, Polymerianalytik I and II, Georg Thieme-Verlag, Stuttgart 1977). The average particle size d ^ o is the diameter that has 50% by weight of the particles that are above this and 50% by weight below. It can be determined by ultracentrifuge measurement (Scholtan, H. Lange, Kolloid, Z. und Z. polymere 250 (1972), 782-1796). Component B may additionally contain homopolymers and / or copolymers B.2 of at least one monomer from the group of vinyl aromatics, vinyl cyanides (unsaturated nitriles), alkyl (meth) acrylates Ci-Cg, acids msaturated carboxylics and derivatives (such as anhydrides and imides) of more saturated carboxylic acids. Particularly suitable are (co) polymers B.2 from B.2.1 50 to 99 parts by weight based on (co) polymer B.2, of at least one monomer selected from the group of vmyl compounds (such as styrene, - methylstyrene), ring-substituted vmyl aromatics (such as, eg, p-methylstyrene, p-chlorostyrene) and Ci-Cg alkyl (meth) acplates, (such as methyl meta-plate, n-butyl acrylate, acrylate of tert-butyl), and B.2.2 1 to 50 parts by weight based on (co) polymer B.2 at least one monomer selected from the group of vmilo cyanides (such as, for example, nitriles msaturados such as acrylonitrile and methacrylonitrile), Ci-Cβ alkyl (meth) acrylates, such as methyl methacrylate, n-butyl acrylate, t-butyl acrylate), more saturated carboxylic acids and more saturated carboxylic acid derivatives, (eg, maleic anhydride and N-Phenlimaleimide These (co) polymers B.2 are similar to reams, thermoplastic and rubber-free. Preferred copolymers are styrene and acrylonitrile. These (co) olimers B.2 are known and can be produced by polymerization of free radicals, particularly by emulsion, suspension, suspension or bulk polymerization. The (co) polymers preferably have average molecular weight Mw (average weight, determined by GPC, light scattering or sedimentation) of between 15,000 and 250,000. A pure grafted polymer Bl or a mixture of several polymers grafted according to Bl or a mixture of at least one grafted polymer Bl with at least one (co) polymer B.2, can be used as compound B. If mixtures of several of the graft polymers or mixtures of at least one polymer grafted with at least one (co) polymer, these can be used separately or in the form of a precursor in the production of the compositions according to the invention. These compounds B containing constituents that degrade polycarbonate under typical processing conditions are also particularly suitable for the compositions according to the invention. In particular, those compounds B containing substances that act as bases resulting from their production are also suitable. These can be, for example, residues of auxiliary substances, which are used in the emulsion polymerization or in the corresponding processes of formulation, or additives of polymers that are added deliberately, such as lubricants and release agents.

Compound C Acids according to compound C are preferably selected from at least one group of aliphatic dicarboxylic acids, the aromatic dicarboxylic acids and the hydrofunctional dicarboxylic acids. Citric acid, oxalic acid, terephthalic acid or mixtures of these compounds are especially preferred as compound C. In a preferred embodiment, the acid according to component C is selected such that it undergoes thermal decomposition under the decomposition conditions, with the release of volatile compounds and / or compounds that give a neutral reaction. Thus, neither an acid nor a base remain in the polycarbonate composition as a product of the decomposition of compound C.

D) Other compounds The composition may contain other additives such as compound D. For example, other polymer constituents such as polyalkylene terephthalates may be added to the composition. Polyalkylene terephthalates are reaction products of aromatic dicarboxylic acids or their reaction derivatives, such as dimethyl esters or anhydrides, and aliphatic, cycloaliphatic or araliphatic diols, as well as mixtures of these reaction products. Preferred polyalkylene terephthalates contain at least 80% by weight, preferably at least 90% by weight, based on the dicarboxylic acid compound, terephthalic acid groups and at least 80% by weight, preferably at least 90% by weight, based on the diol compound, ethylene glycol groups and / or 1,4-butanediol. In addition, of the terephthalic acid groups, the preferred polyalogylene terephthalates can contain up to 20 mol%, preferably up to 10 mol%, of a group of other cycloaliphatic or aromatic dicarboxylic acids with 8 to 14 carbon atoms or aliphatic dicarboxylic acids with 4 to 14 carbon atoms. to 12 carbon atoms, such as, for example, groups of italic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, 4,4'-diphenyldicarboxylic acid, succinic acid, adipic acid, sebasic acid, azelaic acid, cyclohexanediacetic acid. In addition to the ethylene glycol or 1,4-butanediol groups, the preferred polyalkylene terephthalates can contain up to 20 mol%, preferably up to 10 mol%, of other aliphatic diols with 3 to 12 carbon atoms or cycloaliphatic diols with 6 to 21 carbon atoms. carbon, eg, 1,3-propanediol groups, 2-ethyl-1,3-propanediol, neopentyl glycol, 1,5-pentanediol, 1,6-pentanediol, 1,4-c-chlorhexanedimethanol, 3-ethyl-2, 4-pentanediol, 2-hexyl-l, 3-hexanediol, 2,2-diethyl-1,3-propanediol, 2,5-hexanediol, 1,4-di- (b-hydroxyethoxy) benzene , 2, 2-bis (4-hydroxycyclohexyl) propane, 2,4-dihydroxy-1, 1,3, 3-tetramethylcyclobutane, 2,2-bis- (4-β-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 3- or 4-hydroxy alcohols or 3- or 4-basic carboxylic acids, eg, in accordance with DE-A 1 900 270 and US-PS 3 692 744. Examples of preferred branching agents are trimesic acid, trimellitic acid, trimethylolethane, trimethylolpropane and pentaerythritol. Particularly preferred are polyalkylene terephthalates produced only with terephthalic acid and its reactive derivatives (e.g., its dialkyl esters) and ethylene glycol and / or 1,4-butanediol and mixtures of these polyalkylene terephthalates. The polyalkylene terephthalate mixtures contain from 1 to 50% by weight, preferably from 1 to 30% by weight, polyethylene terephthalate and 50 to 99% by weight, preferably from 70 to 99% by weight, polybutylene terephthalate. The pore terephthalates are used preferably they generally have an intrinsic viscosity of 0.4 to 1.5 dl / g, preferably 0.5 to 1.2 dl / g, measured in phenol / o-dichlorobenzene (1: 1 parts by weight) at 252C in an Ubbelohde viscometer. The polyalkylene terephthalates can be produced by known methods (cf., eg, Kunststoff-Handbuch, volume VIII, pp. 695 ff., Carl-Hanser-Verlag, Munich 1973). The composition may also contain other conventional polymer additives, such as flame retardants (eg, fluorinated polyolefin compounds, silicone and aramid fiber classes of substances), lubricants and release agents, eg, pentaerythritol tetrastearate. , nucleating agents, antistatic agents, stabilizers, fillers and reinforcing agents (eg, glass or carbon fibers, mica, kaolin, talcum, CaC03 and glass flakes) as well as dyes and pigments (e.g. titanium dioxide or iron oxide). In particular, the composition may also contain these polymer additives which are known to decompose the carbonaceous polycarbonates ba or typical processing conditions for these compositions. Particular mention should be made herein to the oxidic compounds of metals, particularly metal oxides of subgroups 1 to 8 of the periodic table, such as, e.g., titanium dioxide, iron oxide, kaolin and talc, which are generally used as fillers, reinforcing agents or pigments.

Production of the molding compositions and formed articles The thermoplastic molding compositions according to the invention can be produced, eg, by mixing the relevant constituents in a known manner and compositions and melting-extruding them at temperatures from 2002C to 3002C, preferably at 230 to 280SC, in conventional units such as internal mixers, extruders and twin screw extruders. The individual constituents can be mixed in a known manner either consecutively or simultaneously, and either at about 20 C (room temperature) or at an elevated temperature. In a preferred embodiment, the compositions according to the invention are produced by mixing the compounds A to C and optionally the additional compounds D at temperatures in the range of 200 to 300 ° C, preferably from 230 to 280 ° C, and under a pressure not greater than 500 mbar, preferably not more than 200 mbar, in a unit of suitable commercial composition, preferably in a twin screw extruder. The process conditions according to the invention are therefore selected such that the acid according to the compound C decomposes in this process, the forming compounds that are volatile and / or give a neutral reaction, and the products of the volatile decomposition are extracted at least partially from the composition by means of the vacuum that is applied. In another special embodiment of this process, component B is first mixed first with the acid of compound C and optionally other additives according to compound D at temperatures in the range of 180 to 260 ° C and the mixture thus produced is mixed in a second composition step with a temperature in the range of 200 to 300 ° C, preferably 230 to 280 ° C, and under a pressure of not more than 500 mbar, preferably more than 200 mbar, in a unit of commercially available composition with compound A and optionally other compounds D. In another preferred embodiment of this process, the premixing of compounds B and C, optionally together with other additives according to compound D, is passed as a melt of the polymer into a molten stream of compound A , which has a temperature of 220 to 300aC, and the polymer compounds are then dispersed in another. The invention therefore also provides a process for the production of the compositions according to the invention. The molding compositions according to the invention they can be used to produce all types of articles formed. These can be produced, for example, by means of injection molding, extrusion and blow molding processes. Another form of processing is the production of articles formed by thermoforming of the films or films previously produced. Examples of these shaped articles are profile films, all types of covering parts, eg, for domestic application, such as juice presses, coffee machines, mixers; for office equipment, such as monitors, flat screens, laptops, printers, copiers, sheets, pipes, ducts for electrical installations, windows, doors and other profiles for the construction sector (interior accessories and exterior applications) as well as also electrical and electronic parts, such as switches, plugs and plugs and components of utility vehicles, particularly for the automotive sector. In particular, the molding compositions according to the invention can also be used, for example, to produce the following shaped or molded articles: interior fittings for railway vehicles, ships, aircrafts, buses and other motor vehicles, auto parts for automotive vehicles, covers for electrical applications that contain small transformers, covers for data processing equipment and data transfer, covers and cases for medical equipment, massage equipment and cases thereof, toy vehicles for children, flat wall panels, covers for safety equipment, transport containers thermally insulated, mounts for sanitary fittings and bathroom, perforated grill plate covers for ventilation and protections for gardening equipment.

EXAMPLES Compound A Linear polycarbonate based on bisphenol A with a weight average molecular weight Mw of 27500 g / mol (determined by GPC).

Compound B-1 An ABS polymer, produced by pre-formulation of 50% by weight of an ABS grafted polymer produced by an emulsion polymerization process and 50% by weight of a SAN copolymer. Component Bl is distinguished by a weight ratio A: B: S of 17:26:57 and contains substances that act as Bronsted bases resulting from its production, which can be deduced from the powder pH of cold-crushed compound Bl of 8.4, measured on the basis of ISO 787/9.

Component B-2 A physical mixture of 85% by weight, based on component B-2 of an ABS polymer produced by the previous composition of 50 parts of an ABS grafted polymer produced by an emulsion polymerization process and 50 parts by weight of a SAN copolymer, with 15% by weight, based on compound B-2, of another SAN polymer. Component B-2 is distinguished by a weight ratio A: B: S of 20:24:56. The pH of the ABS grafted polymer powder used in compound B-2 is 5.5, from which it can be deduced that the ABS grafted polymer is substantially free of basic impurities resulting from its production. The SAN copolymers used in component B-2 do not contain constituents that act as bases.

Component C-1 Citric acid monohydrate (Merk KGaA, Darmstadt, Germany) Compound C-2 Oxalic acid (Sigma-Aldrich Chemie GmbH, Steinheim, Germany) Compound C-3 Terephthalic acid, > 99% (Fluka, Germany] Compound D-l Irganox B900 (Ciba Specialty Chemicals Inc., Basel Switzerland Compound D-2 pentaerythritol tetrastearate Compound D-3 TiO ?: Kronos 2233 (Kronos Titan GmbH, Leverkusen, Germany); the pH of the powder, measured on the basis of ISO 787/9 in a mixture of 50% by weight and 50% by weight of 2-propanol, is 5.8.

Production and testing of the molding compositions according to the invention Production process 1: The mixing of all the compounds A to D is carried out in a single step of composition in a twin screw extruder (ZSK-25, Werner and Pfleiderer , Stuttgart, Germany) with a melting temperature of about 260SC and under a pressure of about 100 mbar.

Production process 2: The mixing of components B and C is carried out in a first step of composition in an internal mixer of 3 liters at approximately 220eC ba or normal pressure. The previous composition thus produced was mixed with the compound A and the compound D in a second step of composition in a twin screw extruder (ZSK-25, Werner and Pfleiderer, Stuttgart, Germany) with a melting temperature of approximately 260 ° C. under a pressure of approximately 100 mbar. The test pieces were produced in an Arburg 270 type E injection molding machine at 280SC with a long residence time of 7 5 min. Different measurable variables were used as indicators of the processing stability of the molding compositions produced in this way .

Method 1. Change in melt flow (MVR) when the melt is stored at processing temperature The MVR of the composite composition was determined in accordance with ISO 1133 to 2602C with a load of 5 kg. In addition, the MVR of a sample of the composite composition stored at an elevated temperature (280 ° C or 300 ° C) for a certain time (7 5 minutes or 15 minutes) was also determined at 260 ° C with a carqd of 5 kg. The difference between these MVR values before and after the thermal exposure serves as a measure of the degradation in the molecular weight of the polycarbonate and thus the stability of processing of the molding composition.

Method 2: Glass transition temperature of the rubber in the impact experiment Shock resistance in a notched piece ak is determined in accordance with ISO 180/1 A at different temperatures in test rods with dimensions of 80 mm x 10 mm x 4 mm , which were injection molded with a comparatively high temperature of 2802C and with a comparatively long residence time of 7.5 minutes. The vitreous transition temperature of rubber ak represents the temperature at which a tenacious fracture or brittle fracture was observed in about half of all the experiments developed in this notched shock experiment. This is a measure of the processing stability of the molding composition.

Method 3: intrinsic color under more severe processing conditions Again at 280 ° C. and with a residence time of 7.5 minutes, the sheets of the color sample were injection molded and their yellowness index (YI) was measured by spectrophotometry. An intrinsic color of light (ie, a low YI) is an indicator of good processing stability.

The change in the MVR, measured in accordance with ISO 1133 to 2602C with a load of 5 kg before and after storage of the granules for 7 days at 952C and 100% relative humidity, is a measure of the hydrolysis resistance of the molded compositions.

Table 1 It can be seen from the data in Table 1 that, when adding small amounts of acid, the poor processing stability of the polycarbonate compositions caused by the substances that act as bases in component B of the ABS can be easily improved (compare Comparative Example 1 with Examples 1, 3 and 4) Addition of higher amounts of acid does not provide any other improvement in processing stability, but causes deterioration in intrinsic color and also, in some cases, resistance to hydrolysis (compare Example 1 with Comparative Example 2 and Example 4 with Comparative Example 3). The use of those acids which undergo thermal decomposition under the conditions of production of the compositions to release the volatile and / or neutral compounds, such as oxalic acid and citric acid, proves the advantage with respect to the intrinsic color and especially the resistance to hydrolysis (compare Examples 1, 3 and 4). The citric acid proves the advantage in relation to improving the processing stability (compare Examples 1, 3 and 4) . In addition, this proves the advantage in relation to processing stability and hydrolysis resistance to pre-mix components B and C in the melt initially (compare Examples 1 and 2). A process of this tripo test proves the advantage particularly the colored materials, wherein the disadvantages of this process in terms of the natural shading of the molding composition do not become apparent.

Table 2 It can be seen from the data in Table 2 that the processing stability of these compositions which do not contain basic compounds but contain oxidic metal compounds (titanium dioxide in this case) can also be clearly improved by adding small amounts of acid. The resistance to hydrolysis of the molding compositions is not adversely affected by this. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (19)

1. Claims Having described the invention as above, the content of the following claims is claimed as property: 1. Thermoplastic molding compositions, characterized in that they contain A) 10 to 90 parts by weight of aromatic polycarbonate and / or polyester carbonate, B) to 90 parts by weight of a rubber modified graft polymer or a rubber modified grafted polymer precompound with a (co) olimer, or a mixture of a (co) polymer with at least one polymer selected from the group of grafted polymers modified with rubber and the previous compounds of rubber-modified grafted polymer with a (co) polymer, and C) 0.005 to 0.15 parts by weight based on 100 parts by weight of the sum of the components A and B of at least one acid organic aliphatic and / or aromatic carboxylic acid, and / or one, wherein component C is mixed in the melt of components A and B or where, in a first step, the component B is previously mixed with component C and then, in a second step, the resulting mixture of B and C is mixed with a melt containing component A.
2. 2. Thermoplastic molding compositions according to claim 1, characterized in that they contain 0.01 to 0.15 parts by weight of component C.
3. 3. Thermoplastic molding compositions according to claim 1, characterized in that they contain from 0.015 to 0.13 parts by weight of component C
4. 4. Thermoplastic molding compositions according to one of the preceding claims, characterized in that it contains a compound C at least one acid selected from the group of aliphatic dicarboxylic acids, aromatic dicarboxylic acids and hydroxy-functional dicarboxylic acids.
5. 5. Thermoplastic molding compositions according to one of the preceding claims, characterized in that they contain as component C, citric acid, oxalic acid or terephthalic acid or a mixture thereof.
6. 6. Thermoplastic molding compositions according to one of the preceding claims, characterized in that they contain as citric acid component C.
7. 7. Thermoplastic molding compositions according to one of the preceding claims, characterized in that they contain from 40 to 80 parts by weight, based on the sum of components A and B, of polycarbonate aromatic and / or polyester carbonate.
8. Thermoplastic molding compositions according to one of the preceding claims, characterized in that they contain from 55 to 75 parts by weight, based on the sum of components A and B, of aromatic polycarbonate and / or polyester carbonate.
9. 9. Thermoplastic molding compositions according to one of the preceding claims, characterized in that they contain constituents that act as bases.
10. 10. Thermoplastic molding compositions according to one of the preceding claims, characterized in that they contain a rubber-modified grafted polymer produced in an emulsion polymerization process, which contains constituents that act as bases or residual amounts of the polymerization or substances process aids that act as bases that result from their production.
11. Thermoplastic molding compositions according to one of the preceding claims, characterized in that they contain at least one component selected from the group consisting of polyalkylene terephthalate, flame retardants, anti-drip agents, lubricants and release agents, nucleating agents , antistatic agents, stabilizers, fillers and agents reinforcers, dyes and pigments.
12. 12. Thermoplastic molding compositions according to one of the preceding claims, characterized in that they contain an oxidic metal compound.
13. 13. Thermoplastic molding compositions according to one of the preceding claims, characterized in that they contain titanium dioxide.
14. 14. Process for the production of composicrons according to claim 1, characterized in that the mixing of the components is carried out at temperatures in the range of 200 to 300eC and under a pressure not higher than 500 mbar in a unit of commercially available composition.
15. 15. Process for the production of compositions according to claim 1, characterized in that component B is first mixed with acid C at temperatures in the range of 180 to 2602C and the mixture thus produced is then mixed with component A and optionally Other components in a second step of composting in a unit of commercially available composition at a temperature in the range of 200 to 300 ° C and under a pressure not higher than 500 mbar.
16. 16. Process for the production of compositions according to claim 1, characterized in that the component B is the first one previously mixed with the acid C at temperatures in the range of 180 to 260 C and this premix was passed as a polymer melt into a molten stream of component A and which has a temperature of 200 to 300SC, and the polymer components were then dispersed in other.
17. 17. Use of the thermoplastic molding compositions according to one of claims 1 to 13 for the production of formed articles.
18. 18. Articles formed, characterized in that they contain a composition according to one of claims 1 to 13.
19. 19. Articles formed according to claim 18, characterized in that the article formed is a part of a motor vehicle, railway vehicle, aircraft, or water vehicle, or covers for electrical applications that contain small transformers, covers for data processing and data transfer equipment, covers and cases for medical equipment or massage equipment, covers for domestic applications, vehicle parts of a vehicle toy, flat wall panels, covers for safety equipment, thermally insulated transport containers, a molding for sanitary fittings and bathrooms, perforated grill plate covers for ventilation and protections for gardening equipment.