MXPA99006212A - Thermoplastic molding materials - Google Patents

Abstract

The invention relates to thermoplastic molding materials containing A) 10 to 99 wt.%of a vinyl aromatic polymer with a syndiotactic pentadene content of 30 mol%, B) 0.1 to 20%of delaminated stratified silicate (phyllosilicate), C) 0 to 50 wt.%other additives and processing agents, wherein the weight percentages of constituents A) to C) amount to 100%.

Description

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"COMPOSITIONS OF MOLDING THERMOPLAS ICAS" The invention relates to thermoplastic molding compositions comprising A) from 10 percent to 99 percent by weight of a vinylaromatic polymer having a content of at least 30 mole percent of syndiotactic pentads, B) of 0.1 percent a 20 percent by weight, from a delaminated phyllosilicate, C) from 0 percent to 50 percent by weight of other additives and processing aids where the total percentages by weight of components A) to C is 100 percent. hundred. The invention also relates to a process for preparing these molding comositions, with their use for producing fibers, films and shaped articles of any type, and with the shaped articles obtainable in this way. Due to their property profile, the polymers of the vinylaromatic compounds, in particular the polystyrenes, are used in many sectors, for example, as packaging materials or as insulation coatings for metals or plastics specifically in electrical applications.

- - A process for preparing isotactic polystyrene is described in Patent Number GB-A 826 021. However, isotactic polystyrene crystallizes so slowly that it can not be injection molded. Patent Numbers EP-A 535 582 and EP-A 584 646 describe processes for preparing syndiotactic polystyrene by reacting styrene in the presence of a metallocene complex and a co-catalyst. Syndiotactic polystyrene has high chemical resistance, high rigidity, good dimensional stability and good dielectric properties. In technical applications, even the rigidity of the syndiotactic polystyrene is often insufficient and therefore it is usual to increase the stiffness by mixing with glass fibers. A disadvantage here is that there is a deterioration in the surface properties of the injection molded parts and in the flow properties of the polymer melt. At the same time, the density of materials increases. The atactic polystyrene containing a delaminated phyllosilicate is known from A. Akelah, A, Moet, J. Mat. Sci. 1996, 31, 3589-3596. The thermal resistance and fluidity of these shaped compositions and / or articles are insufficient for many applications.

- - An object of the present invention is to provide vinylaromatic polymers in which filler or filler materials are present and have a balanced property profile. There must be in particular a combination of good fluidity with high thermal resistance, together with low density and good surface properties. We have found that this object is achieved by means of the molding compositions defined at the beginning. Preferred embodiments are provided in the sub-claims. Surprisingly, the combination of the syndiotactic vinyl aromatic polymers with the delaminated phyllosilicates provides molding compositions which are easy to process and have very good thermal resistance, good surface properties and low density. The novel molding compositions contain, as component A), from 10 percent to 99 percent by weight, preferably from 30 percent to 99 percent by weight, and in particular from 50 percent to 98 percent by weight of a vinylaromatic polymer having a content of at least 30 mole percent, preferably at least 50 mole percent, and, in particular, at least 90 mole percent, of syndiotactic pentads.

The proportion of syndiotactic pentads is usually determined by magnetic resonance spectroscopy ^ C. For further details, reference may be made to the article by M. Kobayashi, T. Nakaoki, N. Ishihara, Macromolecules 1990, J.D. Savage, Y.K. Wang, H.D. Stidham, M. Corbett, S.L. Hsu, Macromolecules 1992, 25, 3164, A. Grassi, P. Longo, G. Guerra, Makromol, Chem., Rapid Commun. 1989, 10, 687, M.A. Gómez, A.E. Tonelli, Macromolecules 1990, 23, 3385 and D. Capitani, C. de Rosa, A. Ferrando, A. Grassi, A.L. Segre, Macromolecules 1992, 25, 3874. Component A) is preferably reconstituted from vinylaromatic monomers of the formula I wherein R 1 is hydrogen or carbon alkoxy, R 2 to R 2, independently of one another, are hydrogen, alkyl of 1 to 12 carbon atoms, aryl of 6 to 18 carbon atoms or halogen, or two adjacent radicals together are groups having from 4 to 15 carbon atoms. Preference is given to the use of vinylaromatic monomers of formula I wherein R 1 is hydrogen and R 2 to R 4 are hydrogen, alkyl of 1 to 4 carbon atoms, chlorine, phenyl, biphenyl, naphthalene or anthracene or two adjacent radicals together are groups having from 4 to 12 carbon atoms, providing, for example, naphthalene derivatives or anthracene derivatives, as the compounds of formula I. Examples of these preferred compounds are: styrene, p-methylstyrene, p-chlorostyrene, , 4-dimethylstyrene, 4-vinylbiphenyl, vinylnaphthalene or vinylanthracene. Mixtures of different vinylaromatic compounds can also be used but it is preferred to use only one vinylaromatic compound. Particularly preferred vinylaromatic compounds are styrene and p-methylstyrene. The preparation of the vinylaromatic compounds of the formula I is known per se and is described, for example, in Beilstein 5, 367, 474, 485.

For the purposes of the invention, vinylaromatic polymers A) are also star polymers obtainable by polymerizing the aforementioned vinylaromatic monomers with a branched monomer building block containing at least two vinylaromatic functional radicals, in the presence of a catalyst, of an agent cation former and, if desired, an aluminum compound. These have high molecular weights of 500,000 to 10,000,000 and at the same time low melt viscosities of less than 500 milliliters for 10 minutes at 290 ° C and a load of 10 kilograms and, compared to syndiotactic styrene of comparable molecular weight, they have significantly higher final group functionalities. The functionality of the final group is generally greater than 0.5 mole percent, particularly preferably greater than 0.8 mole percent. These properties can be adjusted over a wide scale by the molar ratio of the vinylaromatic monomer to the building blocks of the branching monomer. The branching monomers used can be the compounds of the formula II wherein: Ra is hydrogen, halogen or an inert organic radical having up to 20 carbon atoms, wherein for p > 2, Ra can be identical or different and the two Ra radicals together with the metal atom bonded thereto can form a ring with 3 to 8 members, and Ra can also be a conventional complex coordinating group, if M is a metal of transition, B is hydrogen, alkyl of 1 to 4 carbon atoms or phenyl; Rc is hydrogen, alkyl of 1 to 4 carbon atoms, phenyl, chloro or an unsaturated hydrocarbon radical having from 2 to 6 carbon atoms; M is C, Si, Ge, Sn, B, Al, Ga, N, P, Sb, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Zn, Cd; n is from 2 to 6; is from 0 to 20; and p is from 0 to 4; with the exception that the sum of n + p corresponds to the valence of M.

These monomers can be obtained, for example, through the Grignard compounds of the chloroalkylstyrenes with the appropriate carbon compounds, the metal compounds or transition metal compounds, e.g., the halogen compounds. Examples of these reactions, wherein M is silica, germanium or tin, are described in the article by K. Nakanishi, J. Chem. Soc. Perkin Trans I, 1990, page 3362. Specific preference is given to the building blocks. of branching monomer of the formula I wherein M is carbon, silicon, germanium, tin or titanium, since these are obtained are easily obtained. The index m preferably is from 0 to 8, particularly preferably from 0 to 4. The novel molding compositions contain, as component B), from 0.1 percent to 20 percent by weight, preferably from 1 percent to 10 percent by weight and in particular from 2 percent to 9 percent by weight of a delaminated phyllosilicate. The term phyllosilicate is generally taken to mean the silicates in which the tetrahedra of SÍO4 are linked in continuous two-dimensional networks. (The empirical formula for the anion is (YES2052-) n). The individual layers are linked by the cations that remain between them, the - cations in the naturally occurring phyllosilicates which are mostly Na, K, Mg, Al and / or Ca. The thicknesses of the layer of these silicates before delamination are usually from 5 to 100 angstrom units of preferably 5. to 50 angstrom units and in particular from 8 to 20 angstrom units. Examples of synthetic and natural phyllosilicates are montmorillonite, smectite, illite, sepiolite, paligorskite, muscovite, alervardite, amesite, hectorite, fluorohectorite, saponite, beidelite, talc, nontronite, stevensite, bentonite, mica, vermiculite, fluorovermiculite, halosite and the varieties of synthetic mica containing fluorine. For the purposes of the invention, the delaminated phyllosilicates are taken as implying that the phyllosilicates wherein the distances between the layers have first been increased by reaction with the hydrophobizers and then the addition of the monomer (commonly referred to as swelling, e.g., with styrene). The delamination of the layers is preferably provided by a distance of at least 40 angstrom units, preferably at least 50 angstrom units, between the layers in the shaped article is carried out by subsequent polymerization of the monomers - - vinylaromatics in the presence of the hydrophobic and swollen phyllosilicate (see E.P. Giannelis, Adv. Mater. 8, (1996) pages 29 to 35). To increase the distance between the layers (hydrophobicization), the phyllosilicates are reacted (before the preparation of the novel molding compositions) with the hydrobophilizers, also referred to as onium ions or onium salts. The cations of the phyllosilicates are replaced by organic hydrophobicizers; the desired distances between the layers can be adjusted by the type of organic radical and depend on the type of monomer or specific polymer in which the phyllosilicate has not been incorporated. Either some or all of the metal ions can be exchanged. The exchange of all metal ions is preferred. The quantity of interchangeable metal ions is usually provided in milliequivalents (meq) per 100 grams of phyllosilicate and is called ion exchange capacity. Phyllosilicates having a cation exchange capacity of at least 50 milliequivalents per 100 grams, preferably 80 to 130 milliequivalents per 100 grams, are of course preferred.

Suitable organic hydrophobizers are derived from oxonium, ammonium, phosphonium and sulfonium ions, which carry one or more organic radicals. Examples of suitable hydrophobizers are those having the formula III and / or IV; III IV wherein: R-7, R8, R9- and R! 0, independently of one another, are hydrogen, a straight or branched chain hydrocarbon radical, saturated or unsaturated having from 1 to 40, preferably from 1 to 20 carbon atoms, which may be unsubstituted or may carry at least one functional group, or 2 of the radicals are linked to one another, in particular to provide a heterocyclic radical of 5 to 10 carbon atoms, D is phosphorus or nitrogen, E is oxygen or sulfur, u is an integer from 1 'to 5, preferably from 1 to 3, and G is an anion. Suitable G anions are derived from protonic acids, in particular from mineral acids, giving - Preference is given to ions derived from halogens, such as chlorine, bromine, fluorine and iodine, and to sulfate, sulfonate, phosphate, phosphonate, phosphite and carboxylate in particular to acetate. The phyllosilicates used as starting materials are usually reacted in the form of a suspension. The preferred suspension medium is water, if desired, in a mixture with alcohols, in particular low molecular weight alcohols having from 1 to 3 carbon atoms. It may be advantageous to use a hydrocarbon, for example heptane, together with the aqueous medium, since hydrophobicized phyllosilicates are generally more compatible with hydrocarbons than with water. Examples of other suitable suspending media are ketones and hydrocarbons. Preference is generally given to a solvent that is miscible in water. When the hydrophobizer is added to the phyllosilicate, an ion exchange is carried out as a result of which the phyllosilicate usually becomes more hydrophobic and precipitates from the solution. The metal salt produced as the by-product of the ion exchange preferably is soluble in water, with the result that the hydrophobicized phyllosilicate can be isolated, for example by filtration, as a crystalline solid.

The exchange of ions to a considerable degree is independent of the reaction temperature. The temperature of preference is greater than the crystallization temperature of the medium and less than its boiling temperature. In aqueous systems, the temperature is from 0 ° C to 100 ° C. preferably from 40 ° C to 80 ° C. For syndiotactic vinylaromatic polymers, it is preferred to use hydrophobicizers wherein R-7, R8, R9 and, if desired, R10, independently of one another, are methyl, ethyl, propyl, isopropyl, chloromethyl, benzyl, p-methylbenzyl, or, very particularly preferably, p-vinylbenzyl. Other suitable vinylaromatic radicals R "7, R8 and R9 are alkoxystyrene, alkylstyrenes containing silyl groups, aminostyrenes, vinylbenzyldimethoxyphosphide, ethylvinylbenzenesulfonate, amino-substituted alkylstyrenes and alkylstyrenes containing ether groups, carboxyl groups or carboxylate groups. Preferred have the formula Illa and / or IVa: nia IVa wherein R "7, R ^ y, if appropriate, R ^ yu and G are as defined above for the compounds of formulas I II and IV, and can be an integer from 0 to 20, and Rll to R1 independently of each other, are hydrogen, alkyl of 1 to 20 carbon atoms, aryl of 6 to 18 carbon atoms or halogens or two adjacent radicals together are groups having from 4 to 15 carbon atoms Examples of preferred ions are trimethyl (o-, m-, p-) vinylbenzylammonium, triethyl (o-, m-, p-) vinylbenzylammonium, diphenyldimethylammonium, diphenyldiethyl ammonium, trimethyl (4-vinylnaphthyl) ammonium, trimethyl (o-, m-, p-) vinylbenzylphosphonium, di (o-, m-, p-) vinylbenzylsulfonium, triphenyl (o-, m-, p-) vinylbenzylphosphonium, triphenyl (o-, m-, p-) inylphenylphosphonium, tri (o-, m-, p-) vinylbenzyloxonium, and tri (o-, m-, p- vinyl phenyloxonium, with trimethylbenzyl vinyl ammonium ions being particularly preferred. A preferred sulfonium ion is (p-, m-, o-) vinyldimethyl-methylenebenzylsulfonium. The preparation can be carried out by processes known per se (eg Stirling, The Chemistry of the Sulfonium Group, Part 1, 1981 pages 267 to 312 and pages 313 to 385, Wiley New York, Deady et al., Austr J. Chem 32 (1979), page 1735; Meerwein et al., Arch. Pharm. 291/63 (1958), page 541 ff Other suitable hydrophobicizers and processes for their preparation are described, inter alia, in Patent Numbers WO 93 / 4117, WO 93/4118, EP-A-398 551 and DE-A 36 32 865. After hydrophobization, the phyllosilicates have a distance between the layers of 10 angstrom units to 40 angstrom units, preferably from 13 to 20 units. Angstrom The distance between the layers usually means the distance from the lower limit of the upper layer to the upper limit of the lower layer The length of the sheets is usually up to 2000 Angstrom units, preferably up to 1500 angstrom units. The hydrophobicized phyllosilicate in the manner described above is then mixed in suspension or as a solid, with the vinylaromatic monomers and the polymerization is carried out in the usual manner. It is possible here to further increase the distance between the layers by reacting (swelling) the phyllosilicate with the vinylaromatic monomers at a temperature of from 0 ° C to 300 ° C, preferably from 25 ° C to 120 ° C, and in particular from 40 ° C at 100 ° C, for a residence time of 5 to 180 minutes, preferably 10 to 120 minutes. Depending on the residence time and the type of monomer selected, the distance between the layers is further increased by from 10 to 150 angstrom units, preferably from 20 to 50 angstrom units. The polymerization is then carried out in the presence of a metallocene catalyst, a cation forming agent and, if desired, an aluminum compound, in the usual manner. The polymerization is carried out in a particularly advantageous manner with the simultaneous application of shear stress, the shear stresses being in accordance with DIN 11 443 being preferably from 10 to 105 Pa, in particular from 10 ^ to 10 ^ Pa.

The metallocene complexes suitable for preparing the vinylaroid polymer in the presence of the hydrophobicized phyllosilicate and, if desired, swelling are those of the formula V wherein: Rl5 to Rl9 are hydrogen, alkyl of 1 to 10 carbon atoms, cycloalkyl with 5 to 7 ring members, which by itself can carry alkyl substituents of I to 6 carbon atoms, aryl of 6 to 15 atoms of carbon or arylalkyl and, if desired, two adjacent radicals can also be together cyclic groups having from 4 to 15 carbon atoms, or Si (R20) 3, wherein R20 is alkyl of 1 to 10 carbon atoms, aryl from 6 to 15 carbon atoms or cycloalkyl- from 3 to 10 carbon atoms, K is a metal of the third to sixth subgroup of the Periodic Table of the Elements or a metal of the lanthanoid series Z1 to Z5 are hydrogen, halogen, alkyl of 1 to 10 carbon atoms, aryl of 6 to 15 carbon atoms, alkoxy of 1 to 10 carbon atoms or aryloxy of 1 to 15 carbon atoms yza Z5 are 0, 1, 2, 3, 4 or 5, the sum of Z + Z2 + Z3 + X + Z5 corresponding to the valence of M minus the number 1. Particularly preferred metallocene complexes of formula V are those wherein M is a metal of the fourth sub-group of the Periodic Table of Elements, in particular titanium and? TX are alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms or halogen. Examples of these preferred metallocene complexes are: pentamethylcyclopentadienyltitanium trichloride, pentamethylcyclopentadienyltrimethyltitanium and pentamethylcyclopentadienyltitanium trimethoxide.

Metallocene complexes such as those described in Patent Number EP-A 584 646 may also be used. Mixtures of two different metallocene complexes have proved to be especially suitable, but it is also possible to use mixtures of up to 5 different metallocene complexes. It is preferred to use here a mixture of pentamethylcyclopentadienyltrimethyl and pentamethylcyclopentadienyl tri-ethoxide. Complex compounds of this type can be synthesized by methods known per se, preferably by reacting the corresponding substituted cyclic hydrocarbon anions with titanium halides, zirconium. hafnium, vanadium, niobium or tantalum. The Journal of Organometallic Chemistry, 369 (1989), 359-370, inter alia, provides examples of corresponding preparation processes. Examples of the appropriate compounds forming the metallocene ions are the open chain or cyclic aluminoxane compounds of the formula VI or VII 'Al-f-0 Al-3 R21 (vi) R21- ^ I m R21 wherein R ^ is alkyl of 1 to 4 carbon atoms, preferably methyl or ethyl, and is an integer of 5 to 30, preferably 10 to 25. These oligomeric aluminoxane compounds are usually prepared by reacting a trialkylaluminium solution with water as described, inter alia, in Patent Numbers EP-A 284 708 and US-A 4,794,096. The resulting oligomeric aluminoxane compounds are usually mixtures of several long chain molecules, both linear and cyclic, so that m should be considered as a mean value. The aluminoxane compounds can also be mixed with other alkyl metal compounds, preferably with alkylaluminium compounds. Other suitable compounds which form the metallocene ions are in particular the specific resistant uncharged Lewis acids, the ionic compounds which have Lewis acid cations and the ionic compounds that have Brónsted acids as the cation. Preferred strong or resistant uncharged Lewis acids are the compounds of formula VIII Ml?!? 2X3 (VIII) wherein M.1 is an element of the third major group of the Periodic Table, in particular B, Al or Ga, preferably B,? l, X2 and X3 are hydrogen, alkyl of 1 to 10 carbon atoms, aryl of 6 to 15 carbon atoms, alkylaryl, arylalkyl, haloalkyl or haloaryl, in each case having from 1 to 10 carbon atoms in the alkyl radical and from 6 to 20 carbon atoms in the aryl radical, or fluorine, chlorine, bromine or iodine, in particular haloaryls, preferably pentafluorophenyl. Specific preference is given to the compounds of formula VIII, wherein λ, X2 and X3 are preferably tris (pentafluorophenyl) borane. These compounds and processes for their preparation are known per se and are described, for example, in Patent Number WO 93/3067.

Suitable ionic compounds having Lewis acid cations are compounds of formula IX [(Aa +) Q1Q2 ... Qz] d + (IX) where A is an element of the first to the sixth major group or the first to the eighth sub-groups of the Periodic Table, Q_ to Qz are radicals that have a single negative charge , such as alkyl of 1 to 28 carbon atoms, aryl of 6 to 15 carbon atoms, alkylaryl, arylalkyl, haloalkyl, haloaryl, in each case, having from 6 to 20 carbon atoms, in the aryl radical and 1 at 28 carbon atoms in the alkyl radical, cycloalkyl of 1 to 10 carbon atoms either unsubstituted or substituted with alkyl of 1 to 10 carbon atoms, halogen, alkoxy of 1 to 28 carbon atoms, aryloxy of 6 to 15 carbon atoms, silyl or mercaptile a is composed of integers from 1 to 6, z is made up of integers from 0 to 5 d is the difference a - z, where d, without However, it is greater than or equal to 1. Carbonate cations, oxonium cations, sulfonium cations and cationic transition metal complexes are particularly suitable especially the triphenylmethyl cation, the silver cation and the cation of cation. 1,1'-dimethylferrocenyl. Preferably they have non-coordination counterions, in particular boron compounds, as also mentioned in Patent Number WO 91/09882, preferably tetrakis (pentafluorophenyl) borate. Ionic compounds having Bronsted acids as cations and also preferably non-coordinating counterions are mentioned in Patent Number WO 93/3067, with the preferred cation being N, N-dimethylanilinium. Vinyl aromatic compounds can be polymerized in solution, in bulk, in suspension or in the gas phase. It is preferred to function in solution, examples of solvents being aromatic hydrocarbons such as benzene, toluene, ethylbenzene or xylenes, and ethers, such as diethyl ether, dibutyl ether, ethylene glycol dimethyl ether or tetrahydrofuran, or aliphatic hydrocarbons such as propane, n-butane, isobutane or pentane, or mixtures of the different solvents, or in bulk.

The polymerization can be carried out under a wide variety of conditions, with the appropriate temperatures being within the range of 0 ° C to 150 ° C, preferably 10 ° C to 100 ° C, with the appropriate pressures being 0.1 to 100. bar, preferably from 1 to 5 and the appropriate polymerization time periods being from 0.1 to 24 hours, preferably from 0.5 to 6 hours. The metallocene complexes are preferably used without a sustenance, but may also be used with a sustenance. Examples of suitable supports are silica gels, especially those of the formula Si? 2-aAl2? 3, where a is a number within the scale of 0 to 2, preferably 0 to 0.5; essentially, therefore, aluminosilicates or silicon dioxide. Preferred livelihoods have a particle diameter within the range of 1 to 200 microns, in particular 30 to 80 microns. These products can be obtained commercially, e.g., as Grace's Gel 332. Examples of other carriers or carriers are finely divided polyolefins, such as finely divided polypropylene or polyethylene, and also polyethylene glycol, polybutylene terephthalate, polyethylene terephthalate, polyvinyl alcohol, polystyrene, polybutadiene, polycarbonates or copolymers thereof.

In the polymerization the use can be made, in addition, of alkylaluminum compounds, those which are particularly suitable being trimethylaluminum, triethylaluminum, triisopropylaluminum, tri-n-propylaluminum, triisobutylaluminum and tri-n-butylaluminum, but in particular triisobutylaluminum. The addition of these alkylaluminium compounds is particularly appropriate when the compounds forming the metallocene ions are uncharged, strong Lewis acids, the ionic compounds having Lewis acid cations and the ionic compounds having the Brónsted acids as cations. It has proven advantageous if the molar ratio of the vinylaromatic compound to the metallocene-forming compound falls within the range of 102: 1 to 107: 1., preferably 103: 1 to 106: 1. The molar ratio of the compound forming the metallocene ions to the total molar amount of metallocene complexes preferably lies within the range of 10-2: 1 to 107: 1, in particular 102: 1 to 105: 1. It is also possible to use two different metallocene complexes, the molar ratio of a metallocene complex to another metallocene complex preferably being within the range of 10-3: 1 to 103: 1, in particular 10-2: 1 to 10: 1 If three or more are used metallocene complexes, the formulation can vary so greatly that a metallocene complex is present as well as a 1000-fold molar excess as compared to the metallocene complex of the next highest concentration. However, it is preferred here if the molar excess is at most 100 times. When an alkylaluminum compound is used, a molar ratio which has proved to be particularly suitable is from 10,000: 1 to 10: 1, preferably from 1000: 1 to 100: 1 of the alkylaluminium compound with respect to the whole amount of the complexes of metallocene. The polymerization is preferably carried out under a pressure of 0.5 to 30 bar, preferably of 1 to 20 bar. The reaction is usually carried out at a temperature of -78 ° C to 150 ° C, preferably 0 ° C. to 120 ° C, but it is also possible to place a gradient from 0 ° C to 120 ° C through the course of the reaction. The polymerization is preferably carried out in the vinylaromatic monomer as the reaction medium, i.e. in bulk. The alkylaluminoxane or trialkylaluminum compound can be contacted prior to polymerization in the vinylaromatic monomer and delivered in a regulated manner to the reactor via a regulated supply pump. After the regulated supply in the vinylaromatic monomer, the catalyst metallocene is supplied in a regulated manner using a pump, in a dissolved form or in the case of supported catalysts, suspended, in the usual organic solvents, such as cyclic or acyclic hydrocarbons, eg, isobutane, n-butane, tertiary butane, pentane, hexane or heptane, or aromatic solvents, eg benzene, toluene or ethylbenzene, or oxygen-containing solvents, e.g., tetrahydrofuran, halogenated solvents, e.g., dichloromethane, nitrogen-containing solvents, e.g., N-methylpiperidine, etc. Suitable reactors are a stirred reactor, an autoclave, a continuous kneading apparatus and vertical reactors, e.g. (see Patent Number DE-A 196 31 365). The molar masses of the prepared polymers are within the range of 1000 to 107 grams per mole, preferably 10,000 to 106 grams per mole and in particular 50,000 to 500,000 grams per mole. The preparation of the appropriate star polymers, carried out, as described above, in the presence of the phyllosilicate, can be based on the processes described in Patent Number DE-A 196 34 375. The novel molding compositions can contain , as component C), up to 50 weight percent, preferably up to 30 weight percent, and in Particularly up to 8 weight percent of the additives and additional processing aids. Suitable flame retardant agents, which may be used in amounts of up to 15 weight percent are the phosphorus-containing red phosphorus compounds and the nitrogen-containing compounds, such as melamine and melamine cyanurate. In principle, any flame retardant agent is suitable. Examples of suitable stabilizers are octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, triethylene glycol bis-3 (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, thiodipropionate. of dilauryl and tris (nonylphenyl) phosphite or mixtures thereof. Other compounds that can be used for stabilization are thiobisphenols, alkylidenebisphenols, alkylphenols, substituted dicyclopentadienes, hydroxybenzyl compounds, acylaminophenols, polyhydroxyphenylpropionates, amines, thioethers, phosphites, phosphonites and zinc dibutyldithiocarbamate in amounts up to 2 weight percent. Examples of antioxidants that may be used are organic sulfides, phosphites, quinone and their derivatives, aromatic nitro and nitroso compounds, substituted in particular o-disubstituted phenols, sulphonic acids, thiol sulphinates, thiosulfoxyl acids, dithiocarba and dithiophosphates, individually or in mixtures, in amounts up to 2 weight percent. The lubricants used can be low molecular weight fatty acid esters, fatty alcohols, esters of dicarboxylic acid, calcium stearate, amide wax, stearic acid and hydroxystearic acid, mountain wax, PE waxes and paraffins, such as white oil. The additives C) can be incorporated into components A) and B) using a conventional apparatus, such as extrusion apparatus, the extruded material being cooled and crushed. The novel molding compositions have good thermal resistance, flowability and low density. They can be converted without difficulty to provide configured items that have good surfaces. The configured items have a layer structure A - B - AZTnB, layer A being the thermoplastic matrix and layer B being the delaminated phyllosilicate. Examples of applications are electrical and electronic components, such as printed circuit boards, plug connectors, chip carriers and capacitor films, automotive components, such as underfloor coatings, coatings surface, microwave utensils and housings for hot water pumps and hot water pipes.

Examples Component B The preparation of vinylbenzyltrimethylammonium chloride and the reaction with montmorillonite are carried out based on the process under 2.1 and 2.2 as on page 3590 in A. Akelah, A. Moet, J. Mat. Sci. 31, 1996. Montmorillonite had a cation exchange capacity of 90 milliequivalents per 100 grams. The montmorillonite hydrophobicide with vinylbenzyltrimethylammonium is referred to as component B) which is presented below.

Example 1 104.2 grams (1 mole) of styrene was mixed with 3. 13 grams of component B) in a round bottom flask with an inert nitrogen atmosphere. The mixture was stirred for 1 hour and then heated to 60 ° C. The stirring was continued for an additional 15 minutes at this temperature and this mixture was mixed with 8.16 milliliters of methylaluminoxane (MAO) from Witco (1.53 M in toluene) and 2.08 milliliters of diisobutylaluminum hydride DIBAH (1.0 M in cyclohexane) from Aldrich. The mixture was then mixed with 9.5 milligrams (4.16 X 10 ~ 5 moles) of trimethyl of pentamethylcyclopentadienyltitanium Cp.Time3. The temperature of the content was adjusted to 60 ° C. and the polymerization was allowed to continue for 2 hours, after which it was terminated by the addition of methanol. The resulting polymer was washed with methanol and dried at 50 ° C under reduced pressure. The molar masses and their distribution were determined by high temperature GPC at 135 ° C, using 1, 2, 4-trichlorobenzene as the solvent. The polystyrene standards with critical distributions were used for calibration. The molar mass Mw was 342,900, with a D distribution of Mw / Mn = 2.3. The syndiotactic proportion, measured as pentadas, was determined by means of 3C nuclear magnetic resonance in the manner of > 98 percent. The conversion was 78 percent based on the styrene monomer used.

Formulation of the molding composition: 97 weight percent syndiotactic polystyrene 3 weight percent of component B) Example 2 104.2 grams (1 mole) of styrene were mixed with 5.21 grams of component B) in a round bottom flask with an inert nitrogen atmosphere. The mixture was stirred for 1 hour and then heated to 60 ° C. Stirring was continued for an additional 15 minutes at this temperature and this mixture was mixed with 8.16 milliliters of methylaluminoxane (MAO) from Witco (1.53 M in toluene) and 2.08 milliliters of diisobutylaluminum hydride DIBAH (1.0 M in cyclohexane) from Aldrich. The mixture was then mixed with 9.5 milligrams (4.16 x 10-moles) of trimethyl pentamethylcyclopentadienyltitanium Cp. iMe3. The temperature of the content was adjusted to 60 ° C and the polymerization was allowed to proceed for 2 hours, after which it was terminated by adding methanol. The resulting polymer was washed with methanol and dried at 50 ° C. under reduced pressure. The molar masses and their distribution were determined by GPC at a high temperature at 135 ° C, using 1,2,4-trichlorobenzene as the solvent. The polystyrene standards with critical distributions were used for calibration. The molar mass Mw was 298,700, with a D) distribution of Mw / Mn = 2.4. The syndiotactic proportion, measured in pentads, was determined by meainte nuclear magnetic resonance 13C was>. of 98 percent. The conversion was 76 percent, based on styrene monomer used.

Formulation of the molding composition: 95 weight percent syndiotactic polystyrene 5 weight percent of component B) Comparison example 1 Syndiotactic polystyrene (Xarec® S 100 from Idemitsu Petrochemica Corp., JP) Mw = 197,000 grams per mol D = 2.0 Comparison example 2 Syndiotactic polystyrene with 30 weight percent glass fibers (Xarec® S 131 from Idemitsu Petrochemical Corp., JP) M, w 201,000 grams per mole D = 2.1 Comparison example 3 The atactic polystyrene obtainable by free radical polymerization as described in A. Echte, F. Haaf, J. Hambrecht, Angew. Chem. 93 (1981) page 372 Mw = 158,000 grams per mole D = 3.4 Comparison example 4 The atactic polystyrene with 5 weight percent of component B) obtainable by the process 2.1. to 2.3. by A. Akelah, A. Moet, J. Mat. Sci. 31 (1996), page 3590 Mw = 158,000 grams per mole D = 3.6 Comparison Example 5 1. 0 mol (104.2 grams) of styrene in a round-bottomed flask with an inert nitrogen atmosphere was heated to 60 ° C and mixed with 8.16 milliliters of methylaluminoxane (MAO) from Witco (1.53 M in toluene) and 2.08 milliliters of hydride diisobutylaluminum (DIBAH) (1.0 m in cyclohexane) from Aldrich. The mixture was then mixed with 9.5 milligrams (4.16 x 10 * 5 moles) of pentamethylcyclopentadienyltitanium Cp * TiMe 3. The temperature of the contents was adjusted to 60 ° C and the polymerization was allowed to advance for 2 hours, after which it was given terminated by adding methanol The resulting polymer was washed with methanol and dried at 50 ° C under reduced pressure.

The molar masses and their distribution were determined by high temperature GPC at 135 ° C, using 1,2,4-trichlorobenzene as the solvent. The polystyrene standards with critical distributions were used for calibration. The molar mass Mw was 322,100, with a distribution D) of Mw / Mn = 2.1. The syndiotactic proportion measured in pentadas was determined by nuclear magnetic resonance 1 C and was > 96 percent. The conversion was 84 percent, based on the styrene monomer used. The standard test specimens were injection molded from the molding compositions of Examples 1 and 2 and comparison examples 1 to 5 at a melting temperature of 290 ° C to 310 ° C and a mold surface temperature of ° C at 150 ° C. The results of the measurements and the test methods are shown in the table.

Table 1 Specification of the Test Density [g / cm3] DIN 53 479 Modulus of Elasticity [MPa] DIN 53 457 HDT B [° C] ISO 75 MVI (5 kg / 300 ° C) [ml / 10 '] DIN 53 735 Table 1 (continued) Eg Ex 2c 3c 4c 5c 1. 06 1.01 1.01 1.25 1.05 1.07 1.05 6100 7000 2500 9500 3300 6800 3800 187 > 250 116 > 250 80 84 115 109 113 106 19 25 *) 19 *) 105 *) measured at 5 kilograms per 200 ° C in accordance with ISO 1133 (Comparison Examples le - 5c)

Claims (10)

1. CLAIMS: 1. A thermoplastic molding composition comprising A) from 10 percent to 99 percent by weight of a vinylaromatic polymer having a content of at least -30 mole percent of syndiotactic pentads, B) of 0.1 per one hundred to 20 weight percent, of a delaminated phyllosilicate, C) from 0 percent to 50 weight percent of other additives and processing aids where the total weight percentages of components A) to C) is of 100 percent.
2. 2. A thermoplastic molding composition according to claim 1, which contains a vinylaromatic polymer A) having a content of at least 50 mole percent of syndiotactic pentads.
3. 3. A thermoplastic molding composition according to claim 1 or 2, wherein the component A) is reconstituted from vinylaromatic monomers of the formula I wherein R is hydrogen or alkyl of 1 to 4 carbon atoms, R 2 to R 6, independently of one another, are hydrogen, alkyl of 1 to 12 carbon atoms, aryl of 6 to 18 carbon atoms or halogen, or two radicals Adjacent together are groups having from 4 to 15 carbon atoms.
4. 4. A thermoplastic molding composition as claimed in any of claims 1 to 3, wherein component A) is reconstituted from styrene, p-methylstyrene, p-chlorostyrene, 2,4-dimethylstyrene, 4-vinylbiphenyl, vinylnaphthalene, vinylanthracene or a mixture of these.
5. 5. A thermoplastic molding composition according to any of claims 1 to 4, containing as the phyllosilicate B), montmorillonite, smectite, illite, sepiolite, paligorskite, muscovite, alervardite, to esita, hectorite, talc, fluorohectorite, saponite , beidelite, nontronite, stevensite, bentonite, mica, vermiculite, fluorovermiculite, haloesite or synthetic micas containing fluorine or mixtures thereof.
6. 6. A process for preparing a thermoplastic molding composition according to any of claims 1 to 5, comprising reacting the phyllosilicate with hydrophobicizers, adding vinylaromatic monomers and then carrying out the polymerization in the presence of a metallocene catalyst, a compound that forms metallocenium ions and, if desired, an aluminum compound.
7. The use of a thermoplastic molding composition according to any of claims 1 to 5, to produce fibers, films and shaped articles.
8. 8. A shaped article obtainable from a thermoplastic molding composition according to any of claims 1 to 5.
9. 9. An article configured in accordance with claim 8, having a layer structure. wherein layer A is the thermoplastic matrix and layer B is delaminated phyllosilicate.
10. 10. An article configured according to claim 8 or 9, wherein the distance between the layers of delaminated phyllosilicate is at least 40 angstrom units.