WO2000047665A1

WO2000047665A1 - Thermoplastic nanocomposites

Info

Publication number: WO2000047665A1
Application number: PCT/EP2000/001088
Authority: WO
Inventors: Stefan Grutke; Martin Weber; Christof Mehler
Original assignee: Basf Aktiengesellschaft
Priority date: 1999-02-10
Filing date: 2000-02-10
Publication date: 2000-08-17
Also published as: EP1153075A1; DE19905502A1; AU2547800A; JP2002536523A; CN1346385A

Abstract

The invention relates to thermoplastic nanocomposites which contain a) a thermoplastic plastic (A), b) at least one compound (B) whose structure consists of negatively charged phyllosilicates and cations interposed in between them (delaminated, surface-treated phyllosilicates) which is evenly dispersed in component (A), c) a further phyllosilicate (C) which is not surface-treated and which has an average size of < 50 νm and length/diameter (l/d) ratio of < 20. The invention further relates to a method for producing said nanocomposites and to their use.

Description

Thermoplastic nanocomposites

The invention relates to thermoplastic nanocomposites with a balanced advantageous profile of mechanical properties.

Composite materials made from organic polymers such as polyamides and layered silicates are known. These materials are characterized by high rigidity. In addition to an improvement in the rigidity, the toughness decreases due to the addition of the layered silicates.

A difficulty in the production of composite materials from organic polymers and phyllosilicates (layered silicates) is the intimate, permanent mixture of the inorganic and the organic material.

A combination of these organic and inorganic materials was achieved, for example, by coupling the inorganic and organic components with organosilanes. However, such a modification is cumbersome and expensive.

No. 4,789,403 describes the production of compositions from organic material, for example polyamides, and layered silicates. The layered silicates are first mixed intimately with organic monomers, comonomers or prepolymers in a mill for better miscibility with the organic material in untreated form. This uniform powder is then polymerized at elevated temperature in an H ₂ atmosphere to give the desired composite material. All possible layered silicates such as halloysite, illite, kalolinite, montmorillonite or polygorskite can be used as layered silicates. Furthermore, a permanent mixing of the organic material with the inorganic material can be achieved by surface treatment of the layered silicate (hydrophobization). Layered silicates of this type contain cations embedded in their negatively charged lattice, as a result of which the layer spacing between the silicate layers is widened (delaminated layered silicates) and the layered silicates disintegrate into individual layers when the organic monomer is subsequently polymerized in the presence of the layered silicates. However, some of the layered silicates treated in this way do not completely delaminate. Especially if the nanocomposites are not produced "in situ" by a direct polymerization of the organic monomers in the presence of the layered silicates, but by a technically much simpler mixture of all starting materials, the delamination of the layered silicates is often incomplete. This results in the even distribution of the individual layers Layered silicates in the plastic (organic material) are not optimal, particularly when the nanocomposites are produced by mixing, which leads to materials which have no advantageous properties compared to materials mixed with undelaminated minerals.

Mixing in the sense of the present invention is preferably the assembly of all components from which the nanocomposites are composed, e.g. B. by a twin-screw extruder to understand the finished nanocomposite.

It is therefore an object of the present invention to provide thermoplastic nanocomposites which, even in the case of manufacture by assembly, have an optimal distribution of the delaminated layers of the layered silicate in the plastic used and a balanced, advantageous mechanical profile. This object is achieved by thermoplastic nanocomposites containing a) a thermoplastic (A), b) at least one compound (B) which is structurally composed of negatively charged phyllosilicates and cations between them (delaminated, surface-treated phyllosilicates), which are uniformly in component (A) is dispersed, c) a further phyllosilicate (C) which has an average size of <50 μm and a length / diameter (1 / d) ratio of <20.

The thermoplastic nanocomposites according to the invention are characterized in that component (C) is not surface-treated.

The non-surface-treated phyllosilicates (component (C)) have a size of less than 50 μm, preferably less than 30 μm, particularly preferably from 15 to 25 μm. Processing by assembly can be carried out in a conventional system, e.g. done in an extruder and is much less expensive and therefore more economical than an "in situ" production of the thermoplastic nanocomposites.

Compared to known thermoplastic nanocomposites, the thermoplastic nanocomposites according to the invention have a higher heat resistance, higher strength, higher rigidity and a high toughness of injection molded parts produced therefrom. In addition, the anisotropy of linear expansion given by nanocomposites is overcome. The improvement in toughness while maintaining rigidity is particularly surprising.

Compared to glass fiber reinforced plastics, an improvement in the surface and comparable mechanical properties with a lower filler content and thus lower density are achieved. The proportion of component (C) used in the total mass of the thermoplastic nanocomposites is low. In general, 0.1 to 15% by weight, preferably 1 to 10% by weight and particularly preferably 2 to 6% by weight, of component (C), based on the total mass of the thermoplastic nanocomposite, is used.

The thermoplastic nanocomposites according to the invention preferably contain a) 10 to 99.89% by weight of component (A), b) 0.01 to 15% by weight, preferably 1 to 10% by weight, particularly preferably 2 to 6% by weight % of component (B), c) 0.1 to 15% by weight, preferably 1 to 10% by weight, particularly preferably 2 to 6% by weight of component (C), d) 0 to 50 % By weight of further fillers (D), e) 0 to 50% by weight of further additives (E), in which the sum of all components gives 100% by weight.

Component A: thermoplastics

The thermoplastics are preferably selected from polyamides, vinyl polymers, polyesters, polycarbonates, polyaldehydes and polyketones.

Lactams such as ε-caprolactam, onantlactam, capryllactam and lauryllactam and mixtures thereof, preferably ε-caprolactam, are suitable as polyamide-forming monomers. Other polyamide-forming monomers that can be used are, for example, dicarboxylic acids, such as alkanedicarboxylic acids having 4 to 14 carbon atoms, in particular 6 to 10 carbon atoms, such as adipic acid, pimelic acid, suberic acid, azelaic acid or sebacic acid, and terephthalic acid and isophthalic acid, diamines such as C ₄ - to C _{] 2} -alkyldiamines, in particular with 4 to 8 carbon atoms such as hexamethylene diamine, tetramethylene diamine or Octamethylenediamine, also m-xylylenediamine, bis (4-aminophenyl) methane, bis (4-aminophenyl) propane-2,2 or bis (4-aminocyclohexyl) methane, and mixtures of dicarboxylic acids and diamines, each individually in any combination in relation to one another, but advantageously in an equivalent ratio such as hexamethylene diammonium adipate, hexamethylene diammonium terephthalate or tetramethylene diammonium adipate, preferably hexamethylene diammonium adipate and hexamethylene diammonium terephthalate, and mixtures of lactams and disalts. Polycaprolactam, polyamides which are composed of hexamethylene diamine and adipic acid and polyamides which are composed of caprolactam, hexamethylene diamine, isophthalic acid and / or terephthalic acid have attained particular industrial importance.

Monomers suitable for the production of vinyl polymers are ethylene, propylene, butadiene, isoprene, chloroprene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, styrene, methylstyrene, divinylbenzene, acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate Isobutyl acrylate, tert-butyl acrylate, methyl acrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-

Butyl methacrylate, isobutyl methacrylate, tert.-butyl methacrylate, acrylamide, methyl acrylamide, ethyl acrylamide, n-propylacrylamide, isopropyiacrylamide, acrylonitrile, vinyl alcohol, norbornadiene, N-vinyl carbazole, vinyl pyridine, 1-butene, isobutene, vinylidene ether, l-methyl-4-butyl vinylidene Methyl vinyl ketone, vinyl vinyl ketone, methyl vinyl ether, vinyl vinyl ether, vinyl vinyl sulfide and acrolein. These monomers can be used alone or in combination with each other. Preferred vinyl polymers are polystyrene, in particular syndiotactic polystyrene, polyethylene, polypropylene and polyvinyl chloride.

Furthermore, polyesters are suitable as thermoplastic plastics, preferably based on terephthalic acid and diols, and particularly preferred are polyethylene terephthalate and polybutylene terephthalate. Other suitable thermoplastics are polycarbonates, polyketones and polyaldehydes such as polyoxymethylene.

Polyesters and polyamides are particularly preferably used, very particularly preferably polyamides, as the thermoplastic (A).

Component B: delaminated, surface-treated phyllosilicates

A phyllosilicate (layered silicate) is generally understood to be silicates in which the SiO ₄ tetrahedra are connected in two-dimensional infinite networks. (The empirical formula for the anion is (Si O ^{2 "} ) _n ) - The individual layers are connected to each other by the cations between them, mostly as cations Na, K, Mg, Al or / and Ca in the naturally occurring layered silicates are available.

Examples of synthetic and natural phyllosilicates (layered silicates) are montmorillonite, smectite, illite, sepiolite, palygorskite, muscovite, allevardite, amesite, hectorite, fluoroctorite, saponite, beidellite, talc, nontronite, stevensite, benticulite, vermiculite, vermiculite, vermiculite, vermiculite, mica and called fluorine-containing synthetic talc types.

A delaminated phyllosilicate in the sense of the invention is to be understood as meaning phyllosilicates in which the layer spacings are initially increased by reaction with so-called hydrophobizing agents and, if appropriate, subsequent addition of monomers (so-called swelling e.g. with caprolactam).

The layer thicknesses of such silicates before delamination are usually from 5 to 100 Å, preferably 5 to 50 Å and in particular 8 to 25 Å (distance from one upper layer edge to the next upper layer edge). Subsequent assembly of the hydrophobized and optionally swollen phyllosilicate with thermoplastic materials (component A), preferably with polyamides, and component C, delaminates the layers, which in the thermoplastic nanocomposite preferably lead to a layer spacing of at least 40 Å, preferably at least 50 Å.

To increase the layer spacing (hydrophobization), the phyllosilicates (before the production of the thermoplastic nanocomposites according to the invention) can be reacted with so-called hydrophobizing agents. These are often referred to as onium ions or onium salts.

The cations of the phyllosilicates are replaced by organic hydrophobizing agents, the type of organic residue being able to set the desired layer spacings, which depend on the type of the particular monomer or polymer in which the phyllosilicate is to be incorporated.

The exchange of the metal ions can take place beyond the stoichiometry, completely, partially or not at all. A complete exchange of the metal ions is preferred. The amount of exchangeable metal ions is usually given in milliequivalents (meq) per 100 g of phyllosilicate and is referred to as the ion exchange capacity.

Phyllosilicates with a cation exchange capacity of at least 50, preferably 80 to 130 meq / 100 g are preferred.

Suitable organic water repellents are derived from oxonium, ammonium, phosphonium and sulfonium ions, which can carry one or more organic radicals. Suitable hydrophobicizing agents are those of the general formula I and / or II:

II

where the substituents have the following meaning:

R ¹ , R ² , R ³ , R ⁴ independently of one another are hydrogen, a straight-chain, branched, saturated or unsaturated hydrocarbon radical having 1 to 40, preferably 1 to 20, carbon atoms, which can optionally carry at least one functional group, or 2 of the radicals are linked to one another, in particular to form a heterocyclic radical having 5 to 10 carbon atoms, and

X is phosphorus or nitrogen, Y Y is oxygen or sulfur, n is an integer from 1 to 5, preferably 1 to 3 and Z is an anion.

Suitable functional groups are carboxyl, hydroxyl, nitro or sulfo groups, carboxyl groups being particularly preferred since such functional groups result in improved binding to the end groups of the polyamide.

Suitable anions Z are derived from proton-providing acids, in particular mineral acids, with halogens such as chlorine, bromine, fluorine, iodine, sulfate, sulfonate, phosphate, phosphonate, phosphite and carboxylate, in particular acetate, being preferred. The phyllosilicates used as starting materials are usually implemented in the form of a suspension. The preferred suspending agent is water, optionally in a mixture with alcohols, especially lower alcohols with 1 to 3 carbon atoms. It can be advantageous to use a hydrocarbon, for example heptane, together with the aqueous medium, since the hydrophobized phyllosilicates are usually more compatible with hydrocarbons than with water.

Other suitable examples of suspending agents are ketones and hydrocarbons. A water-miscible suspending agent is usually preferred. When the hydrophobicizing agent is added to the phyllosilicate, an ion exchange occurs, as a result of which the phyllosilicate usually precipitates out of the solution. The metal salt formed as a by-product of the ion exchange is preferably water-soluble, so that the hydrophobized phyllosilicate as a crystalline solid by e.g. Filtering can be separated.

The ion exchange is largely independent of the reaction temperature. The temperature is preferably above the crystallization point of the medium and below its boiling point. In aqueous systems, the temperature is between 0 and 100 ° C, preferably between 40 and 80 ° C.

For polyamides as component A, alkylammonium ions are preferred, which can also be obtained by reacting suitable aminocarboxylic acids, preferably ω-aminocarboxylic acids such as ω-aminododecanoic acid, ω-aminoundecanoic acid, ω-aminobutyric acid, ω-aminocaprylic acid or ω-aminocaproic acid with conventional mineral acids, for example hydrochloric acid or sulfuric acid Phosphoric acid or methylating agents such as methyl iodide are available.

Further preferred alkylammonium ions are laurylammonium, myristylammonium, palmitylammonium, stearylammonium, pyridinium, Octadecylammonium, monomethyloctadecylammonium and dimethyloctadecylammonium ions.

Suitable phosphonium include for example Docosyltrimethyl- phosphonium, Hexatriacontyltricyclohexylphosphonium, phosphonium Octadecyltriethyl- phosphonium, Eicosyltriisobutylphosphonium, Methyltrinonylphosphonium, Ethyltrihexadecylphosphonium, Dimethyldidecylphosphonium, Diethyldiocta- decylphosphonium, Octadecyldiethylallylphosphonium, Trioctylvinylbenzyl-, Dioctyldecylethylhydroxyethylphosphonium, Docosyldiethyl- dichlorbenzylphosphonium, Octylnonyldecylpropargylphosphonium, triisobutyl perfluordecylphosphonium, Eicosyltrihydroxymethylphosphonium, Triacontyl- triscyanethylphosphonium and called bistrioctylethylene diphosphonium.

Other suitable water repellents include in WO 93/4118, WO 93/4117, EP-A 398 551 and DE-A 36 32 865.

After the hydrophobization, the phyllosilicates generally have a layer spacing of 10 to 50 Å, preferably 13 to 40 Å. The layer spacing usually means the distance from the lower layer edge of the upper layer to the upper layer edge of the lower layer.

As far as possible, the phyllosilicate which has been rendered hydrophobic in the above manner is freed of water, for example by drying, such as spray drying. In general, the hydrophobized phyllosilicate treated in this way contains from 0 to 10% by weight, preferably from 0 to 5% by weight, of water. The hydrophobized phyllosilicate can then be used as a suspension in a suspending agent which is as anhydrous as possible, the alcohols or the low-boiling alkanes being particularly suitable, for example, or mixed as a solid, for example with polyamide monomers. The hydrophobized phyllosilicates are preferably used as a solid. It is possible to further increase the layer spacing by the phyllosilicate with polyamide monomers, for example at temperatures from 25 to 300 ° C, preferably from 80 to 280 ° C and in particular from 80 to 260 ° C over a residence time of usually 5 to 120 minutes, preferably from 10 to 60 minutes, (so-called swelling). Depending on the duration of the residence time and the type of monomer chosen, the layer spacing is additionally increased by 10 to 150 Å, preferably by 10 to 50 Å. The length of the leaflets is usually up to 2000 Å, preferably up to 1500 Å. Prepolymers that are present or are building up generally also contribute to the swelling of the layered silicates.

Component C: non-surface treated phyllosilicates

Suitable phyllosilicates as component (C) can be found in Hollemann, Wiberg, Textbook of Inorganic Chemistry, de Gruyter, 1985, pages 771 to 776. Examples of synthetic and natural phyllosilicates (layered silicates) are smectite, illite, sepiolite, palygorskite, muscovite, allevardite, amesite, hectorite, fluorochemistite, saponite, beidellite, talc, nontronite, stevensite, bentonite, mica, hallicite, vermiculite, fluorine vermilite called.

Talc and kaolinite are preferred. Talc is particularly preferred, talc with an average particle size of 15 to 25 μm is very particularly preferred.

These phyllosilicates are used as component (C) in their non-surface-treated form. Component D: fillers

Particulate or fibrous fillers are suitable as fillers. Carbonates such as magnesium carbonate or chalk are suitable as particulate fillers. Fibrous fillers are preferably used. Examples of suitable fibrous fillers are carbon fibers, potassium titanate whiskers, aramid fibers or glass fibers. Glass fibers are particularly preferably used. If glass fibers are used, they can be equipped with a size and an adhesion promoter for better compatibility with the matrix material. In general, the carbon and glass fibers used have a diameter in the range from 6 to 16 μm. The glass fibers can be incorporated both in the form of short glass fibers and in the form of endless strands (rovings). Carbon or glass fibers can also be used in the form of fabrics, mats or glass silk rovings. The fillers can be present in amounts of generally 0 to 50% by weight, preferably 15 to 40% by weight, particularly preferably 20 to 35% by weight, based on the total weight of the compositions.

Component E: additives

The compositions may also contain additives. Such additives include processing aids, stabilizers and oxidation retardants, agents against heat decomposition and decomposition by ultraviolet light, lubricants and mold release agents, flame retardants, dyes and pigments and plasticizers. Their proportion is generally from 0 to 50% by weight, preferably up to 30% by weight, particularly preferably from 1 to 25% by weight, based on the total weight of the composition.

Pigments and dyes are generally present in amounts of from 0 to 4% by weight, preferably from 0.5 to 3.5% by weight and particularly preferably from 0.5 to 3% by weight, based on the total weight of the compositions, contain. The pigments for coloring thermoplastics are generally known, see, for example, R. Gächter and H. Müller, Taschenbuch der Kunststoffadditive, Carl Hanser Verlag, 1983, pp. 494 to 510. The first preferred group of pigments are white pigments such as zinc oxide and zinc sulfide , Lead white (2 PbCO ₃ • Pb (OH) ₂ ), lithopone, antimony white and titanium dioxide. Of the two most common crystal modification (rutile and anatase type) of titanium dioxide, the rutile form is used in particular for the white coloring of the thermoplastic nanocomposites according to the invention.

Black color pigments that can be used according to the invention are iron oxide black (Fe ₃ O ₄ ), spinel black (Cu (Cr, Fe) ₂ O ₄ ), manganese black (mixture of manganese dioxide, silicon dioxide and iron oxide), cobalt black and antimony black and particularly preferably carbon black, which is mostly used in the form of furnace black or gas black (see G. Benzing, Pigments for Paints, Expert Verlag (1988), p. 78 ff).

Of course, inorganic colored pigments such as chrome oxide green or organic colored pigments such as azo pigments and phthalocyanines can be used according to the invention to adjust certain shades. Pigments of this type are generally commercially available.

It may also be advantageous to use the pigments or dyes mentioned in a mixture, e.g. Carbon black with copper phthalocyanines, since it is generally easier to disperse colors in thermoplastics.

Oxidation retarders and heat stabilizers which can be added to the thermoplastic compositions according to the invention are, for example, halides of metals of group I of the periodic table, for example sodium, potassium, lithium halides in combination with copper (I) halides, for example chlorides, Bromides or iodides. The halides, especially copper, can also contain electron-rich π ligands. Cu halide complexes with, for example, triphenylphosphine may be mentioned as examples of such copper complexes. Zinc fluoride and zinc chloride can also be used. Furthermore, sterically hindered phenols, hydroquinones, substituted representatives of this group, secondary aromatic amines, optionally in combination with phosphorus-containing acids or their salts, and mixtures of these compounds, generally in concentrations of up to 1% by weight, based on the weight of the Mix, can be used.

Examples of UV stabilizers are various substituted resorcinols, salicylates, benzotriazoles and benzophenones, which are generally used in amounts of up to 2% by weight.

Lubricants and mold release agents, which are generally added in amounts of up to 1% by weight to the thermoplastic composition, are stearic acid, stearyl alcohol, alkyl stearates and amides, and esters of pentaerythritol with long-chain fatty acids. Salts of calcium, zinc or aluminum of stearic acid and dialkyl ketones, e.g. Distearyl ketone can be used.

Process for producing the thermoplastic nanocomposites according to the invention

The thermoplastic nanocomposites according to the invention can be produced in various ways.

In-situ method

In the in-situ method, the hydrophobized (= delaminated) phyllosilicate (B)

(such as Cloisite 30A from Southern Clay Products ^®, Laporte Co., England) were mixed in suspension or as a solid, to the thermoplastic resin (A) polymerizable monomers. The swelling of the hydrophobic phyllosilicate with the monomers. The subsequent polymerization of the monomers can be carried out in a conventional manner. The nanocomposites obtained in this way are then made up with component (C) and, if appropriate, further components (D) and (E).

For this purpose, the hydrophobized phyllosilicates (B) are suspended in liquid monomers polymerizable to component (A) (thermoplastics) and in the presence of generally 0.1 to 8% by weight, preferably 0.1 to 7% by weight. Water, based on the monomers, polymerized. The polymerization is preferably carried out in the presence of more than 0.2% by weight of water, for example from 0.25 to 6% by weight of water.

The water can be added to the suspension. If this suspension already contains water from component B, either no further water is added or only enough water is added that the total amount of water, based on the monomers, is in the range according to the invention.

In order to obtain the best possible mixing, the suspension is advantageously stirred, particularly preferably with shear. For example, stirred tanks are suitable for this. The water is then generally added all at once, in portions or continuously, the temperatures of the suspension generally being in the range from 70 to 100 ° C., preferably in the range from 75 to 95 ° C. The temperature of the water-containing suspension is increased either simultaneously or subsequently, as a rule, to 180 to 330 ° C., preferably 220 to 320 ° C. The suspension can either remain in the unit in which it was produced or be transferred to another reaction vessel before or after the temperature increase or before or after the addition of water. The polymerization is particularly advantageously carried out with simultaneous shear. Various procedures can be used for the production of the compositions according to the invention. The production can be carried out, for example, by means of a batch process or a continuously carried out process.

In the batch process, the water-containing suspension can be polymerized under the temperature and shear conditions given above and under pressure. The pressure is generally in the range from 5 to 30 bar, preferably in the range from 8 to 20 bar (absolute). The residence times are essentially dependent on the temperatures chosen during the polymerization and are generally in the range from 0.5 to 3 hours. In general, after the equilibrium conversion has been reached, the water is evaporated and the pressure is reduced to atmospheric pressure. Water still present in the melt can also lead to a further increase in molecular weight at this pressure. The reaction mixture is then discharged, for example in the form of melting profiles, cooled, advantageously by passing it through a water bath, and comminuted, preferably granulated. As a rule, polyamides obtained in this way, preferably produced, have molecular weights of up to 22000 g / mol, preferably in the range from 8000 to 22000 g / mol.

According to a preferred embodiment, the continuous process is generally carried out in such a way that the water-containing suspension, the temperature of which is in the range from 70 to 100 ° C., preferably from 75 to 95 ° C., is continuously fed to a first reaction zone and there under the above polymerized specified temperature and shear conditions. According to a special embodiment, prepolymers of other or the same monomers can be fed to the first reaction zone in addition to the aqueous suspension. These can originate, for example, from the extraction of product granules (see below). The pressure in the first reaction zone is generally below 5 bar (absolute). It can be, for example, from 1 to 3 bar (absolute). The residence time, which essentially depends on the temperature, pressure and water content of the reaction mixture, is generally chosen in the range from 2 to 5 h, preferably from 3 to 4 h. If prepolymers are added to the first reaction stage, the residence times are generally shorter than 2 h, for example 0.5 to 1 h. In the first reaction zone, when caprolactoam is used, polycondensation is usually carried out up to a molecular weight of 3000 g / mol or above, preferably in the range from 5000 to 7000 g / mol. The end group total concentration can be, for example, in the range from 200 to 600 mmol / kg, preferably from 300 to 400 mmol / kg.

The reaction mixture is passed from the first reaction zone into a second reaction zone. The reaction vessel of the second reaction zone, which can be tubular, for example, is preferably equipped with internals. These include orderly mixing elements such as packing elements (e.g. Raschig rings, spheres or Pall rings), so that a minimum residence time of the unreacted monomers in the melt (in order to achieve a high turnover) is preferably guaranteed, and zones in which the melt is transported only minimally or not at all takes place ("dead zones"), and backmixing is avoided as far as possible. The temperatures in the second reaction zone are generally in the same range as those in the first reaction zone. The residence time in the second reaction zone can vary depending on the type of monomer, temperature, pressure and nature of the The residence time in the second reaction zone is generally longer if no prepolymer has been added in the first reaction zone. The polymer melt is generally discharged from the second reaction zone in the form of melt profiles, cooled by means of a water bath and comminuted, before trains granulated. Polyamides thus obtained can e.g. Have molecular weights in the range of 12,000 to 22,000 g / mol.

Both the compositions obtained by the batch and the continuous process can still contain volatile components such as lactam used (for example in the polymerization of caprolactam) and other monomer units and steam-volatile oligomers. These are usually removed from the polymer granules with water by countercurrent extraction (see, for example, DD-A 206999). Another possibility is gas phase extraction (see EP-A 0 284 968) with a simultaneous increase in molecular weight, in which extraction and annealing can be carried out simultaneously using superheated steam. In a preferred embodiment, the volatile constituents are continuously returned quantitatively to the process, ie preferably to the first reaction zone. For this purpose, the extraction water is preferably concentrated to an extract content of at most 85% by weight and the water content of the concentrate obtained is adjusted by adding fresh monomers so that the polymerization can be carried out in the presence of the amount of water according to the invention. If the polymerization is carried out in this manner is carried out ^'adiabatic expansion to reduce the water content at least as a rule during the polymerization (s. DE-A-19752181).

The desired viscosity number of the end product can also be set in a manner known per se by drying or in the solid phase by heat treatment by polymerization.

The desired viscosity number of the end product is generally in the range from 80 to 350 ml / g, preferably 120 to 200 ml / g (measured as a 0.5% strength by weight solution in 95% strength by weight sulfuric acid, after removal of the insoluble components).

The nanocomposites thus obtained are made up with component (C) (non-surface-treated phyllosilicates) by customary methods, for example by means of extrusion. The compositions produced by the process according to the invention generally contain from 10 to 99.89% by weight, based on the total weight of the compositions, of thermoplastics (component A) and from 0.1 to 15% by weight, preferably from 1 to 10% by weight, particularly preferably 2 to 6% by weight, based on the total weight of the compositions, of non-surface-treated phyllosilicates (component C). The proportion of the delaminated phyllosilicates (component B) is generally from 0.01 to 15% by weight, preferably from 1 to 10% by weight, particularly preferably from 2 to 6% by weight, based on the total weight of the compositions . The proportion of component B is determined by ashing the compositions.

2. Melt intercalation

In a preferred embodiment, the thermoplastic nanocomposites according to the invention can be obtained by the thermoplastic (component A), the delaminated phyllosilicate (component B) and the non-surface-treated phyllosilicate (component C) according to generally known methods, for example by extrusion at temperatures in the range of 160 to 340 ° C, particularly preferably at 240 to 300 ° C, mixes. A twin-screw extruder with high shear is particularly suitable for this, preferably with shear stresses according to DIN 11 443 of 10 to 10 ⁵ Pa, in particular 10 ² to 10 ⁴ Pa. This manufacturing process can be carried out in conventional equipment, for example in extruders, is simple to carry out and is therefore economical. Optimal mixing of the compositions according to the invention is achieved.

The thermoplastic nanocomposites obtained according to the invention are distinguished in particular by excellent toughness with very good rigidity. The thermoplastic nanocomposites according to the invention can be used for the production of moldings. Such moldings can preferably be produced by extrusion, deep drawing or injection molding.

The present invention therefore furthermore relates to moldings obtainable using the nanocomposites according to the invention.

The following examples further illustrate the invention.

Examples

Component B

As component (B) is Cloisite 30A ^® (Southern Clay Products, Laporte Co., England), an already hydrophobized phyllosilicate used.

Production of the thermoplastic nanocomposites according to the invention

WEG I Example 1: a) For hydrophobicization of the phyllosilicates, see: Preparation of component B

b) Production of a polyamide 6 nanocomposite (production of component A in the presence of component B)

3 kg of polymer A and 0.9 kg of layered silicate B are dissolved or suspended in 28 kg of caprolactam. After adding 1000 g of water, the mixture is heated to 250 ° C. in a stirred kettle, the internal pressure being 10 bar. After a precondensation of 2 hours, the vessel is depressurized over a period of 1.5 hours and then post-condensed at 250 ° C. for 2.5 hours. The melt is then discharged from the boiler and granulated. The granules are extracted with hot water.

Packaging of the PA6 nanocomposites with Talkum it extra® (from

Norwegian Tale, Bad Soden, DE) as component C:

The assembly is carried out using a ZSK53 twin-screw extruder at 270 ° C without any additional aids such as lubricants.

WEG II Example 2: a) Hydrophobization

In a 10 1 pressure vessel equipped with a stirrer, a suspension of 4 1 methanol pa, 80 g montmorillonite, 20 g (0.14 mol) di-2-hydroxyethyl-methyl-stearylamine and 26.6 g (0.14 mol) para -Toluenesulfonic acid monohydrate is prepared, stirred vigorously under N atmosphere for 6 h at 75 ° C. and then cooled to room temperature. b) polymerization

The polymerization of caprolactam was carried out in the presence of component B and component C.

Polycondensation in the presence of all starting materials is only possible in a melt kneader. The flowability MVI (ml / 10 ') at 250 ° C was below 1, which made injection molding impossible.

WEG III

Examples 3, 4:

Packaging of all input materials (ZSK 30) at 260 ° C under usual

conditions Comparative examples:

VI: Packaging of 5% talc it extra® VI ': Packaging of 10% talc it extra® V2: Packaging of 5% WoUastonit (= chain silicate) VP283 / 600 AST V3: Pure nanocomposite (path 2) V4: Nanocomposite (path 3 )

Application studies:

The viscosity number of the matrix was determined on 0.5% strength by weight solutions in H ₂ SO at 25 ° C.

The impact strengths (a _n [kJ / m ² ]) were measured on standard notched bars according to ISO 179 Part I.

The tensile test was carried out in accordance with ISO 527-2.

The results are summarized in Table 1.

Table 1:

i t

I.

(B) Brittle fracture measured on milled specimens from a molded plate, 2 mm thick.

* No injection molding processing possible

Claims

claims

1.Thermoplastic nanocomposites containing a) a thermoplastic (A), b) at least one compound (B) which is structurally composed of negatively charged phyllosilicates and cations between them (delaminated, surface-treated phyllosilicates), which are uniform in the component ( A) is dispersed, c) another phyllosilicate (C) which has an average size of <50 μm and a length / diameter (1 / d) ratio of <20, characterized in that component (C) is not surface-treated is.

2. Thermoplastic nanocomposites according to claim 1, characterized in that component (C) has an average particle size of 15 to 25 microns.

3. Thermoplastic nanocomposites according to claim 1 or 2, containing a) 10 to 99.89 wt .-% of component (A), b) 0.01 to 15 wt .-% of component (B), c) 0.1 up to 15% by weight of component (C), d) 0 to 50% by weight of further fillers (D) e) 0 to 50% by weight of further additives (E), in which the sum of all components is 100% by weight % results.

4. Thermoplastic nanocomposites according to one of claims 1 to 3, characterized in that component (A) is a polyamide or a polyester.

5. Thermoplastic nanocomposites according to one of claims 1 to 4, characterized in that component (C) is contained in a proportion of the total mass of 1 to 10 wt .-%.

6. Thermoplastic nanocomposites according to one of claims 1 to 5, characterized in that component (C) is talc or kaolinite.

7. A method for producing thermoplastic nanocomposites according to one of claims 1 to 6 by an in-situ method in which the hydrophobized phyllosilicate (B) is mixed in suspension or as a solid with the monomers polymerizable to the thermoplastic (A), swelling of the hydrophobized phyllosilicate with the monomers and then polymerization of the monomers is carried out and the nanocomposites thus obtained with the

Component (C) and optionally further components (D) and (E) are assembled.

8. A process for producing thermoplastic nanocomposites according to one of claims 1 to 6 by melt intercalation, the thermoplastic (component A), the hydrophobized phyllosilicate (component B) and the further phyllosilicate with an average particle size of <50 μm (component C) and optionally components (D) and (E) are mixed at temperatures in the range from 160 to 340 ° C.

9. Use of thermoplastic nanocomposites according to one of claims 1 to 6 for the production of moldings.

10. Moldings obtainable from thermoplastic nanocomposites according to one of claims 1 to 6.

1. A process for the production of moldings according to claim 10 by extrusion, deep drawing or injection molding.