DE102008031072A1 - Particulate, organically modified silicate layer, which excludes magnesium and silicon cation, as a (semi)metal cation, and comprises an organic residue on its surface, useful as fillers for thermoplastics, preferably transparent plastic - Google Patents

Abstract

Particulate, organically modified silicate layer, which excludes magnesium and silicon cation, as a (semi)metal cation, and comprises an organic residue on its surface, is claimed, where the diameter of the particulate is up to 900 nm. An independent claim is included for the preparation of the particulate, organically modified silicate layer comprising reacting a silicon organic component comprising one or more trialkoxysilane compound of formula (R 1>Si(OR 2>) 3) (I) with silicon compound of formula ((R 5>) 3Si[-O-Si(R 5>) 2] n-O-Si(OR 2>) 3) (II) and a magnesium organic component consisting of one or more magnesium alcoholate group of formula (Mg(OR 4>) 2) (III), in an aqueous free solvent; and adding sufficient amount of water, which permits the complete hydrolysis of (III). R 1>alkyl, alkenyl, aryl, arylene, arylalkyl, alkylaryl, alkylarylene, alkenylaryl, arylalkenyl or arylene-alkyl (all optionally substituted by SH, OH, NH 2, C(O)OH, C(O)NH 2, epoxy, (meth)acryloxy, methacrylamido and/or halo), where the carbon chain and/or -cycle is optionally interrupted by one or more O, S, NH, NR 3>, C(O), C(O)O, C(S)O, C(O)S, C(O)NH, C(S)NH, C(O)NR 3>, C(O)NHC(O), NHC(O)NH, -OC(O)O-, OC(O)NH-, SO x, PO x, or -N=N, and further comprises -C?=C- or -HC=CH-, preferably optionally substituted phenyl, halogenated, preferably fluorinated 1-4C-alkyl or 1-4C-alkylene; R 2>alkyl optionally interrupted by O, S, NH or NR 3>; x : 1-4; R 5>alkyl-, alkenyl-, aryl-, arylene-, arylalkyl-, alkylaryl-, alkylarylene-alkenylaryl-, arylalkenyl- or arylenealkyl group (all optionally substituted by SH, OH, NH 2, C(O)OH, C(O)NH 2, epoxy, (meth)acryloxy, methacrylamido and/or halo), whose carbon chain and/or cycle is optionally interrupted by one or more O, S, NH, NR 3>, C(O), C(O)O, C(S)O, C(O)S, C(O)NH, C(S)NH, C(O)NR 3>, C(O)NHC(O) or -N=N and further contains -C?=C- or -HC=CH-group; R 3>optionally substituted alkyl, aryl, alkylaryl or arylalkyl; n : 0-20; and R 4>optionally substituted alkyl-, aryl- or arylalkyl group, whose carbon chain and/or -cycle is optionally interrupted by O, S, NH or NR 3>.

Description

The The present invention relates to organic phyllosilicates with the Structure and composition of the talc, which as a particle with a average diameter D (n, 50) of less than 1 micron present, as well as a method for their preparation. The novel Particles are particularly suitable for incorporation in transparent Plastics whose mechanical and thermal properties make them without having a negative impact on transparency.

in the Range of transparent thermoplastics (eg polycarbonate, PC, or polymethylmethacrylate, PMMA), it has not yet been possible Nanoparticles completely dispersed in the polymer matrix bring in and so an improvement of the mechanical or thermal To bring about properties without the optical Properties are adversely affected. So changed when using Organoclays in PC or PMMA the color of the Composites from colorless to yellow to gray. The causes for These discolorations are on the one hand in the natural Coloring of the used layer minerals and on the other in the thermal decomposition of the used hydrophobing reagents and / or matrix polymers. At present, no works are known, according to which transparent thermoplastics by means of fillers mechanically and could be thermally strengthened without their Color and transparency negatively influence.

Within composites technology with thermoplastics, inorganic particles have been used as fillers for many years in order to achieve specific properties such as, for example, For example, the mechanical properties (eg with calcium carbonate (CaCO ₃ ) or the flame retardancy properties (eg with magnesium hydroxide (Mg (OH) ₂ ) are typically used, with particles having a particle diameter in the range of just below one Since this is always associated with a deterioration in toughness and optical transparency due to scattering effects, the areas of application of these composites are primarily for non-transparent components.

In In recent years, there have been new developments in the field of manufacture and the use of nanoparticles. So were synthetic nanoparticles in a variety of variations commercially available, e.g. As powder from Degussa After the Aerosil process, the new impulses in the field of nanotechnology gifts. Such nanoparticles are currently used in paint systems with a wide range used, for. B. for anti-graffiti protective coatings or for surface hardening. This is under Among other things, the slight influence on the transparency and color of the Lackes in the production of the desired effects in the foreground.

But also the naturally occurring nanoparticulate raw materials, ie especially layer minerals such as montmorillonite belonging to the smectite group, have contributed significantly to the revitalization of research in the field of nanocomposites through new developments. Thus, in the 1990s, researchers around Okada of Toyota swellable maleic anhydride-modified montmorillonite could hydrophobicize by exchanging intermolecularly bound cations for stearylammonium ions and were thus able to completely exfoliate the individual layer packages by intercalating polymer into the interstices in a plastic ( please refer M. Okamoto et al., Nanoletters, 2001, 1 (6): pp. 295-298 ). This has led to the improvement of many properties of the polymer, e.g. As the strength at almost constant yield strength, increasing the heat resistance and flame behavior, improving the surface quality and scratch resistance and the barrier effect against water and gases. A disadvantage of this method, however, is the thermal instability of stearylammonium, which at high temperatures leads to a strong discoloration (brown or darker). This is unfavorable because such high temperatures occur in the processing of plastics in extruders. The Japanese working group has developed several polymer nanocomposites that have already been used in the automotive industry, such as a phyllosilicate-modified PA 6.6, which is used as an engine cover due to its high heat resistance and low weight. The important thing for the industrial application of these nanocomposites was that the property improvements could be realized at a significantly lower filler content (5-10% by mass (wt .-%) phyllosilicate compared to 30 wt .-% conventional filler) and thus no adverse changes the property image of the plastic or its processing properties detectable.

• 1. In-situ-Polymerisation von Monomeren im Zwischenschichtraum ( E. Manias et al., a. a. O.; X. Kornmann et al., Polymer, 2002, 42 (10): S. 4493–4499 )
• 2. Interkalation in Polymerlösungen und anschließende Entfernung des Lösungsmittels ( G. Schmidt et al., 2001, 661: S. KK5.10.1-KK5.10.6 ; K. Strawhecker et al., Macromolecules, 2001, 34 (24): S. 8475–8482 )
• 3. Interkalation von Schichtsilikaten in einer Polymerschmelze ( E. Manias, MRS Bulletin, 2001, 26 (11): S. 862–863 ).

The phyllosilicates, mostly 3-phyllosilicates such as montmorillonite, have hitherto been rendered hydrophobic predominantly with alkylammonium cations. These are incorporated by exchange reactions in the interlayer galleries of silicates and thus increase the layer spacing of the minerals. In these so-called organically modified phyllosilicates now polymer molecules can be intercalated. This intercalation of polymers can in turn be done in three different ways:

• 1. In-situ Polymerization of Monomers in the Interlayer Space ( E. Manias et al., Supra; X. Kornmann et al., Polymer, 2002, 42 (10): pp. 4493-4499 )
• 2. Intercalation in polymer solutions and subsequent removal of the solvent ( G. Schmidt et al., 2001, 661: S. KK5.10.1-KK5.10.6 ; K. Strawhecker et al., Macromolecules, 2001, 34 (24): 8475-8482 )
• 3. Intercalation of phyllosilicates in a polymer melt ( E. Manias, MRS Bulletin, 2001, 26 (11): pp. 862-863 ).

Suitable particles for this purpose are layer minerals with average aspect ratios (lateral dimensions <100 nm), which are exfoliated by surface modification and shear forces in layer packages or individual layers having a thickness of about 1 nm. In order to maintain color fastness, the minerals must be highly pure and must not have any coloring foreign ions, so that the starting material used is not montmorillonite, which is commonly used in today's nanocomposites, but, for example, synthetic or ultrapure hectorites. mineral Molecular formula aspect ratio montmorillonite M _x [Al _4-x Mg _x ] (Si ₈ ) O ₂₀ (OH) ₄ <1000 hectorite M _x [Mg _6-x Li _x ] (Si ₈ ) O ₂₀ (OH) ₄ <100 Laponite synth. hectorite <50 talc Mg ₃ Si ₄ O ₁₀ (OH) ₂ <10 M mostly = Na

Most literature protocols for the synthesis of an organically modified layered silicate describe a one-step, direct synthesis under mild conditions. The materials for this are members of the 2: 1 trioctahedral phyllo (organo) silicate family, which are based on the structure of the talc: S. Mann et al. ( SL Burkett, A. Press, S. Mann, Chem. Mater. 9 (1997): pp. 1071-1073 ) C. Airoldi et al. ( MG da Fonseca, C. Airoldi, J. Mater. Chem. 10 (2000): pp. 1457-1463 ; MG da Fonseca, JS Barone, C. Airoldi, Clays and Clay Minerals 48 (6) (2000): 638-647 ) and L. Ukrainczyk et al. ( L. Ukrainczyk, RA Bellman, AB Anderson, J. Phys. Chem. B 101 (1997): pp. 531-539 In a typical synthesis procedure, magnesium chloride hexahydrate and the organosiloxane are added in a ratio of 3 to 4, dissolved in methanol, and then an aqueous sodium hydroxide solution is added. The reaction mixture is stirred overnight, then filtered and washed several times with water. KA Carrado et al. ( KA Carrado, L. Xu, R. Csencsits, JV Muntean, Chem. Mater. 13 (2001): pp. 3766-3773 ) first prepare a fresh magnesium hydroxide sol, which is then combined with LiF and the organosiloxane. The mixture is then refluxed for a few days before work-up begins. This method results in a hectorite. N. Lequeux et al. ( J. Minet, S. Abramson, B. Bresson, C. Sanchez, V. Montouillout, N. Lequeux, Chem. Mater. 16 (2004): pp. 3955-3962 ) first hydrolyze the organosilane in ethanol containing hydrochloric acid and magnesium chloride hexahydrate. They then add a correspondingly more concentrated sodium hydroxide solution to initiate the synthesis of the layered silicates. The phyllosilicate precipitates quickly.

• 1. Allen gemeinsam ist, dass die mittlere Teilchengröße im Bereich von einigen Mikrometern liegt. Füllt man transparente Thermoplaste mit diesen großen Teilchen, führt dies zu einer Eintrübung.
• 2. Insbesondere S. Mann et al. , C. Airoldi et al. , L. Ukrainczyk et al. und N. Lequeux et al. ist gemeinsam, dass durch die gewählte Verfahrensführung große Mengen Natriumchlorid entstehen und dass Magnesiumkationen nicht nur intramolekular in den Schichten, sondern auch als Ladungsausgleich an den Teilchenoberflächen intermolekular gebunden vorliegt. Natriumchlorid und insbesondere intermolekular gebundenes Magnesium müssen aus den Teilchen herausgewaschen werden, um die erforderliche Reinheit zu erzielen. Außerdem führt intermolekular gebundenes Magnesium während der Verarbeitung von transparentem Polycarbonat zu einer Depolymerisation und zu deutlichen Verfärbungen. Die Reinigung der Schichtsilikate, um sie von Natrium- und Magnesiumchlorid zu befreien, ist ihrerseits sehr aufwändig, da Schichtsilikate auch als Ionenaustauscher wirken und insbesondere Magnesiumkationen stark binden können. Ein Auslaugen mit konzentrierten Säuren verbietet sich, da dadurch auch das intramolekular gebundene Magnesium herausgelöst wird und die Schichtstruktur der Silikate zerstört wird. Es bleiben undefinierte Polysiloxane übrig, die keinen schichtartigen Aufbau mehr aufweisen und zu Eintrübungen von Polycarbonat führen.

The synthetic rules of these research groups lead to products with the following disadvantages:

• 1. All have in common that the average particle size is in the range of a few micrometers. If you fill transparent thermoplastics with these large particles, this leads to a clouding.
• 2. In particular S. Mann et al. . C. Airoldi et al. . L. Ukrainczyk et al. and N. Lequeux et al. It is common that large amounts of sodium chloride are formed by the chosen procedure and that magnesium cations are intermolecularly bound not only intramolecularly in the layers but also as charge balance on the particle surfaces. Sodium chloride and especially intermolecularly bound magnesium must be washed out of the particles to achieve the required purity. In addition, intermolecularly bound magnesium leads to depolymerization and marked discoloration during processing of transparent polycarbonate. The purification of the phyllosilicates in order to free them from sodium and magnesium chloride, for their part, is very complicated since phyllosilicates also act as ion exchangers and, in particular, can strongly bind magnesium cations. Leaching with concentrated acids is not possible as it removes the intramolecularly bound magnesium and destroys the layer structure of the silicates. There remain undefined polysiloxanes, which no longer have a layered structure and lead to clouding of polycarbonate.

In summary, it can be said that until today no particulate, organically modified Layer silicates are available which, when used as fillers for in particular thermoplastic, transparent plastics ensure the desired transparency and color, inter alia, by having a diameter D (n, 50) of less than 1 μm, preferably of less than 800 nm and at the same time highly pure, ie are substantially or completely free of foreign ions and preferably have a defined composition at least with respect to the ratio of the cation species present. In this case, the diameter specification D (n, x) means that x% of the particles in the number distribution (n), that is 50% in the case of D (n, 50), has a diameter D smaller than or equal to the specified value, that is, below 1 micron and 800 nm, respectively.

The The object of the invention is in the elimination of this defect Provision of appropriate phyllosilicates. These should preferably for use in transparent thermoplastics and especially suitable in polycarbonate and polymethylmethacrylate be. Another object of the invention is in the provision a simple, preferably one-step process for the production of such sheet silicates with small particle size be seen.

In Solution to this problem has surprisingly been found that nano-scale, organically modified phyllosilicates on Make base of talc using a very simple procedure to let. These phyllosilicates contain exclusively cations those of magnesium and silicon, preferably approximately or exactly in the molar ratio of 3: 4, wherein they are at least in The latter case usually has a structure derived from talc. They are also free of adhesive byproducts like Sodium and free of charge balance on the particle surfaces bound, intermolecular magnesium.

Of the Particle diameter of the layered silicates according to the invention is usually in the following ranges: D (n, 50) amounts to between 10 and 900 nm, preferably between 50 and 500 nm and most preferably between about 70 and 300 nm. D (n, 90) usually less than 2 μm, preferably less than 950 nm preferably below 500 nm and most preferably below 300 nm.

It Different organic radicals can be attached to the silicon be, thereby adjusting various properties as needed to let. One of these properties is the refractive index, that of one the plastic in which the phyllosilicates are incorporated should be as similar as possible, if one satisfactory transparency is to be achieved. The organic ones Remains are directed to the surface of the resulting Phyllosilicates off; They can therefore preferably be chosen be that good compatibility of the phyllosilicate with the particular plastic is achieved, in which they are incorporated should. So z. B. the presence of a hydrophobic organic Modification of the layered silicates according to the invention such high affinity to hydrophobic polymers as polycarbonate, that no further modifiers or other additives are needed become. In specific cases, this modification may also be Groups carrying a Einpolymerisierung the sheet silicates in the plastic allow, for. B. ethylenically unsaturated Groups or ester groups. Einpolymerisierung simplifies it the exfoliation of the sheet silicates, d. H. the separation of the individual Layers.

The organically modified phyllosilicates according to the invention are thermally stable and withstand high processing temperatures of polymers.

The Sheet silicates according to the invention are preferably from an organosilicon component and an organomagnesium Component, usually by reaction in a solution or Suspending agent, prepared.

The organosilicon component consists of one or more trialkoxysilanes. These may be selected from those of the formula (I) R ¹ Si (OR ² ) ₃ (I) wherein R ^{1 is} an unsubstituted or substituted alkyl, alkenyl, aryl, arylene, arylalkyl, alkylaryl, alkylarylene-alkenylaryl, arylalkenyl or arylenealkyl group whose carbon chain and / or cycle is simple or in some cases also multiple by O, S, NH, NR ^3, C (O), C (O) O, C (S) O, C (O) S, C (O) NH, C (S) NH, C (O) NR ³ , C (O) NHC (O), NHC (O) NH, -OC (O) O-, OC (O) NH-, SO _x with x = 1, 2, 3, 4, PO _x with x = 1, 2, 3, 4, silicone groups such as - [Si (CH ₃ ) ₂ -O-] with n = 1, 2, 3, 4 to 10 or even higher or -N = N be interrupted or -C≡C- or more -HC = CH groups may contain. When R ^{1 is} substituted, for. B. one or more functional groups such as SH, OH, NH ₂ , -C (O) H, -C (O) OH, -C (O) NH ₂ , epoxy or (meth) acryloxy, (meth) acrylamido present be. One or more of the carbon atoms of R ¹ may instead or additionally Lich with halogen (F, Cl, Br, and / or I) substituted, for example, be halogenated alkyls such as haloethylene. R ³ has in these groups and radicals the meaning of an unsubstituted or substituted alkyl, aryl or alkylaryl or arylalkyl. By the particular choice of R ¹ , the character of the organic modification of the layered silicate is determined, for. B. its hydrophobicity or hydrophilicity or integration ability in the plastic. Thus, R ¹ includes, for example, esters, ethers and amides, but may often be a hydrophobic group such as a substituted or unsubstituted aryl, for example phenyl, or a halogenated, for example fluorinated, alkyl or alkenyl. Further examples of R ¹ are 3-mercaptopropyl, 3-aminopropyl, 3- (methacryloxy) propyl, N-propylethylenediamine.

The radicals R ² may be the same or different; R ² is preferably alkyl, such as. For example, methyl, ethyl, propyl, isopropyl or butyl, preferably ethyl or methyl. In very rare cases, the carbon chain of R ^{2 may} also be interrupted by O, S, NH or NR ³ , where R ^{3 is} as defined above.

Alternatively (if appropriate also in addition, which is not preferred), the organosilicon component can also be selected from trialkoxysilanes of the formula (II) (R ⁵ ) ₃ Si [-O-Si (R ⁵ ) ₂ ] _n -O-Si (OR ² ) ₃ (II) wherein R ^{5 is the} same or different and is an unsubstituted or substituted alkyl, alkenyl, aryl, arylene, arylalkyl, alkylaryl, alkylarylene-alkenylaryl, arylalkenyl or arylenealkyl group, the carbon chain and / or cycle of which is simple or inert in some cases also several times by O, S, NH, NR ³ , C (O), C (O) O, C (S) O, C (O) S, C (O) NH, C (S) NH, C (O) NR ³ , C (O) NHC (O), NHC (O) NH, -OC (O) O-, OC (O) NH-, SO _x where x = 1, 2, 3, 4, PO _{x may be} interrupted by x = 1, 2, 3, 4 or -N = N or may contain -C≡C- or further -HC = CH groups. When R ^{5 is} substituted, e.g. B. one or more functional groups such as SH, OH, NH ₂ , -C (O) H, -C (O) OH, -C (O) NH ₂ , epoxy or (meth) acryloxy, (meth) acrylamido present be. One or more of the carbon atoms of R ⁵ may instead or additionally be substituted with halogen (F, Cl, Br, and / or I), for example, haloalkylene such as haloethylene. R ³ has in these groups and radicals the meaning of an unsubstituted or substituted alkyl, aryl or alkylaryl or arylalkyl. By the particular choice of R ⁵ , the character of the organic modification of the layered silicate is determined, for. B. its hydrophobicity or hydrophilicity or integration ability in the plastic. Thus, R ⁵ includes, for example, esters, ethers and amides, but may often be a hydrophobic group such as a substituted or unsubstituted aryl, for example phenyl, or a halogenated, for example fluorinated, alkyl or alkenyl. Further examples of R ⁵ are 3-mercaptopropyl, 3-aminopropyl, 3- (methacryloxy) propyl, N-propylethylenediamine. n in formula (II) can denote 0, 1, 2, 3, 4 to 10 or even an even greater integer; unless n is 0, it is preferred that either all of R ^{5 are} selected from unsubstituted alkyl, alkenyl, aryl, arylene, arylalkyl, alkylaryl, alkylarylene-alkenylaryl, arylalkenyl or arylenealkyl groups, or that only a radical R ⁵ is interrupted and / or substituted as indicated above.

R ² has the same meaning in the compounds of formula (II) as in the compounds of formula (I).

The organomagnesium component consists of one or more magnesium alcoholates of the formula (III): Mg (OR ⁴ ) ₂ (III) wherein R ^{4 is} an unsubstituted or substituted alkyl, aryl or arylalkyl group whose carbon chain or cycle may optionally be interrupted by O, S, NH or NR ³ , wherein R ^{3 has} the meaning given above for formula (I). Preferably, R ^{4 is} an alkyl of 1 to 6 carbon atoms, more preferably an alkyl of 1 to 4 carbon atoms, and most preferably ethyl or methyl.

The radicals R ^1, R ² and R ^3, R ⁴ and R ⁵ can, as far as they do not include aryl groups, preferably 1 to 20 carbon atoms, more preferably 1 to 8 and still more preferably 1 to 4 carbon atoms. When R ¹ or R ³ are or have aryl radicals, they preferably comprise 5 to 40, more preferably 6 to 20 and most preferably 6 to 10 carbon atoms.

All Alkyl radicals or groups can be straight-chain, branched-chain and / or cyclic.

It is preferred that in each case only one trialkoxysilane of the formula (I) or of the formula (II) and / or a magne siumalkoholat the formula (III) use. Trialkoxysilanes of the formula (I) are preferred over those of the formula (II).

The trialkoxysilane (s) of the formula (I) and / or of the formula (II) and the magnesium alcoholate (s) of the formula (III) are initially charged in a suitable protic or aprotic solvent or suspending agent, which is preferably anhydrous. The initial absence of water ensures that the reaction can be started only with the presence of all starting materials with good Reproduzier availability and thus completely controlled or controlled. Particularly suitable are alcohols, in particular aliphatic alcohols. It is particularly favorable to use alcohols having the formula R ² OH and / or R ⁴ OH, wherein R ^{2 has} the meaning given for the silane of the formula (I) and R ^{4 has} the meaning given for the magnesium alcoholate of the formula (II). Examples include methanol and ethanol. Namely, in these cases, transesterification of the silane compound / magnesium alcoholate as a side reaction can not occur, which could possibly lead to a decrease in reactivity.

In particular, it is advantageous to choose the solvent and the radicals R ² and R ⁴ so that the solvent can be easily separated from the reaction product after the reaction. If a triethoxysilane is used as the silane of the formula (I), magnesium ethanolate is chosen as the magnesium alcoholate of the formula (III) and ethanol is used as the solvent, only the phyllosilicate forms the reaction product and the solvent ethanol in the reaction. The ethanol can be reused as a solvent or for the synthesis of magnesium ethoxide or triethoxysilane. There is a high atomic economy. Such high atom economy reactions are, for economic and environmental reasons, preferable to lower atom economy reactions (such as the reaction of magnesium propylate and tributoxysilane dissolved in ethanol).

The Amount of trialkoxysilane and magnesium alcoholate is chosen that the desired ratio of magnesium ions to silicon ions is formed, which, as mentioned above, preferably is about or exactly 3: 4. It can be assumed be that the cations of the starting materials completely or substantially completely in the layer silicates be incorporated and no or substantially no silicon or magnesium-containing by-products arise.

The reaction of the starting materials is initiated by the addition of water. The water is preferably added in an amount just sufficient for the complete hydrolysis of the magnesium alcoholate. It is preferably stirred in slowly. By these measures, the particles grow slowly and remain small, and you get the desired layered silicate structure. In contrast, rapid hydrolysis is usually disadvantageous because in many cases magnesium-free, spherical SiO ₂ or silicone particles could be formed. It is important to ensure that the hydrolysis of the silane proceeds as possible not faster than that of the magnesium alcoholate; Preferably, it runs a little slower. But also the hydrolysis of the magnesium alcoholate should not be too fast, because otherwise there is a risk that multilayer brucite (Mg (OH) ₂ ) forms before the hydrolyzed silane accumulates.

The method is characterized by the fact that no by-products containing metal ions are formed, which would be difficult to remove from the surface of the phyllosilicate produced. The phyllosilicates produced are in turn characterized by high purity. They contain neither sodium or magnesium chloride nor intermolecularly bound magnesium, which could discolor polycarbonate or lead to its depolymerization. Polycarbonate into which 3% by mass of a hydrophobic layer silicate according to the invention has been stirred with an organic radical R ¹ which gives it a refractive index close to that of the polycarbonate (1.59) is colorless and clearly transparent.

The According to the invention, organically modified phyllosilicates Can be used as a filler for all kinds of transparent Polymers are used, especially for polycarbonate and PMMA. Polycarbonate organo-layer silicate nanocomposite prepared in this manner can z. B. for final discs of a headlamp or used in the field of car (side) glazing so the usual, complex and ecological questionable paintwork to reduce notch sensitivity to avoid polycarbonate or replace glass.

Example:

1.99 g of finely pulverized magnesium ethanolate is added with exclusion of moisture to a mixture of 5.6 ml of triethoxyphenylsilane and 60 ml of absolute ethanol. The mixture is stirred for 5 hours at room temperature. Then, 0.67 ml of distilled water is added and the reaction mixture is stirred for 24 hours at room temperature with exclusion of moisture. The resulting precipitation becomes centrifuged off and washed with absolute ethanol and finally dried. It consists of particles with a diameter D (n, 50) of about 80 nm. The refractive index of the particles is 1.52. The refractive index of polycarbonate is 1.59.

A polycarbonate (PC 2600 from Bayer) was combined with 3% by mass of the layered silicate prepared according to Example and heated to 300 ° C. under a protective gas atmosphere. After melting the polycarbonate, the two components were intimately mixed. From the melt, samples were poured. The transmission of a polycarbonate sample which is filled with the layered silicate according to the invention is in 1 shown as curve 1. For comparison, the same polycarbonate was filled with the same amount of phyllosilicate under the same production conditions, but this phyllosilicate according to the above-described method of S. Mann et al. had been made. The transmission of such a comparative sample is shown in curve 2. It can be seen that the transparency in the wavelength range between about 500 and 1700 nm in the sample produced according to the invention is between values of 70 and almost 80%, while it does not even reach 40% in the comparison sample.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited non-patent literature

• - M. Okamoto et al., Nanoletters, 2001, 1 (6): p. 295-298 [0005]
• E. Manias et al., Supra; X. Kornmann et al., Polymer, 2002, 42 (10): pp. 4493-4499 [0006]
• G. Schmidt et al., 2001, 661: S.KK5.10.1-KK5.10.6 [0006]
• - K. Strawhecker et al., Macromolecules, 2001, 34 (24): pp. 8475-8482 [0006]
• - E. Manias, MRS Bulletin, 2001, 26 (11): pp. 862-863 [0006]
• - S. Mann et al. [0008]
• - SL Burkett, A. Press, S. Mann, Chem. Mater. 9 (1997): pp. 1071-1073 [0008]
• C. Airoldi et al. [0008]
• MG da Fonseca, C. Airoldi, J. Mater. Chem. 10 (2000): pp. 1457-1463 [0008]
• MG da Fonseca, JS Barone, C. Airoldi, Clays and Clay Minerals 48 (6) (2000): pp. 638-647 [0008]
• L. Ukrainczyk et al. [0008]
• L. Ukrainczyk, RA Bellman, AB Anderson, J. Phys. Chem. B 101 (1997): pp. 531-539 [0008]
• - KA Carrado et al. [0008]
• KA Carrado, L. Xu, R. Csencsits, JV Muntean, Chem. Mater. 13 (2001): p. 3766-3773 [0008]
• - N. Lequeux et al. [0008]
• - J. Minet, S. Abramson, B. Bresson, C. Sanchez, V. Montouillout, N. Lequeux, Chem. Mater. 16 (2004): pp. 3955-3962 [0008]
• - S. Mann et al. [0009]
• C. Airoldi et al. [0009]
• L. Ukrainczyk et al. [0009]
• - N. Lequeux et al. [0009]
• - S. Mann et al. [0032]

Claims (11)

Particulate, organically modified phyllosilicate comprising exclusively magnesium and silicon cations as (half) metal cations and organic radicals on its surface, characterized in that it consists of particles with a diameter of D (n, 50) of up to 900 nm. Particulate sheet silicate according to claim 1, which is free of intermolecular bound magnesium. Particulate layered silicate according to claim 1 or 2, wherein the organic radicals are the same or different and can be defined with R ¹ or (R ⁵ ) ₃ Si [-O-Si (R ⁵ ) ₂ ] _n -O, these radicals being the following R ¹ is unsubstituted or substituted alkyl, alkenyl, aryl, arylene, arylalkyl, alkylaryl, alkylarylene, alkenylaryl, arylalkenyl or arylenealkyl, the carbon chain and / or cycle of which is mono- or polysubstituted by O, S, NH, NR ³ , C (O), C (O) O, C (S) O, C (O) S, C (O) NH, C (S) NH, C (O) NR ^3, C (O) NHC (O), NHC (O) NH, -OC (O) O-, OC (O) NH-, -, SO _x where x = 1, 2, 3, 4, PO _x where x = 1, 2, 3, 4 or - N = N- may be interrupted or -C≡C- or further -HC = CH groups may contain, R ⁵ may, if several times in the radical (R ⁵ ) ₃ Si [-O-Si (R ⁵ ) ₂ ] _n -O-, the same or different and is selected from unsubstituted or substituted alkyl, alkenyl, aryl, arylene, arylalkyl, alkylaryl, alkylarylene-alkenylaryl, arylalkenyl or aryl enalkyl groups whose carbon chains and / or cycles are mono- or polysubstituted by O, S, NH, NR ³ , C (O), C (O) O, C (S) O, C (O) S, C (O) NH , C (S) NH, C (O) NR ^3, C (O) NHC (O), NHC (O) NH, OC (O) O-, OC (O) NH-, SO _x with x = 1 , 2, 3, 4, PO _x with x = 1, 2, 3, 4 or -N = N may be interrupted or -C≡C- or further -HC = CH groups may contain, wherein R ^{3 is} an unsubstituted or substituted Alkyl, aryl or alkylaryl or arylalkyl and n is 0 or an integer between 1 and 20. Particulate layered silicate according to claim 3, wherein the radicals R ¹ and / or R ⁵ with SH, OH, NH ₂ , C (O) OH, C (O) NH ₂ , epoxy or (meth) acryloxy, methacrylamido and / or halogen substituted Alkyl, alkenyl, aryl, arylene, arylalkyl, alkylaryl, alkylarylene, alkenylaryl, arylalkenyl or arylenealkyl. Particulate layered silicate according to claim 3, wherein R ¹ and / or R ^{5 are} selected from phenyl, substituted phenyl, halogenated, in particular fluorinated alkyl and halogenated, in particular fluorinated, alkylene, wherein the alkyl or alkylene group is more preferably 1 or 2 to 4 carbon atoms having. Particulate sheet silicate comprising exclusively magnesium and silicon cations as (half) metal cations and organic radicals R ¹ and / or (R ⁵ ) ₃ Si [-O-Si (R ⁵ ) ₂ ] _n -O on its surface, obtained by reacting a organosilicon component consisting of one or more trialkoxysilanes selected from those having the formula (I) R ¹ Si (OR ² ) ₃ (I) and those of the formula (II) (R ⁵ ) ₃ Si [-O-Si (R ⁵ ) ₂ ] _n -O-Si (OR ² ) ₃ (II) wherein R ¹ and R ^{5 are} as defined in any one of claims 3 to 5 and R ^{2 is the} same or different and is optionally interrupted by O, S, NH or NR ³ interrupted alkyl wherein R ^{3 is} as defined in claim 3, having a organomagnesium component consisting of one or more magnesium alcoholates of the formula (III): Mg (OR ⁴ ) ₂ (III) wherein R ^{4 is} an unsubstituted or substituted alkyl, aryl or arylalkyl group whose carbon chain or cycle may optionally be interrupted by O, S, NH or NR ³ , wherein R ^{3 has} the meaning given above in claim 3. Particulate layered silicate according to claim 6, characterized in that the reaction of the organosilicon component with the organomagnesium component takes place in a solvent in the presence of substantially exactly that amount of water needed to produce the magnesia completely hydrolyze the organic component. Particulate sheet silicate according to claim 7, wherein the solvent is an alcohol, preferably methanol or ethanol, is. A process for preparing a particulate, organically modified layered silicate, comprising the steps of: providing an organosilicon component consisting of one or more trialkoxysilanes selected from those of the formula (I) R ¹ Si (OR ² ) ₃ (I) and those of the formula (II) (R ⁵ ) ₃ Si [-O-Si (R ⁵ ) ₂ ] _n -O-Si (OR ² ) ₃ (II) wherein R ¹ and R ^{5 are} as defined in any one of claims 3 to 5 and R ^{2 is the} same or different and is optionally interrupted by O, S, NH or NR ³ interrupted alkyl, wherein R ^{3 is} as defined in claim 3, as well as a organomagnesium component consisting of one or more magnesium alcoholates of the formula (III): Mg (OR ⁴ ) ₂ (III) wherein R ^{4 is} an unsubstituted or substituted alkyl, aryl or arylalkyl group whose carbon chain or cycle may optionally be interrupted by O, S, NH or NR ³ , where R ^{3 has} the abovementioned meaning, in an anhydrous solvent, and - adding water in not more than an amount which allows the complete hydrolysis of the or the Megnesiumalkoholate (s) of the formula (III). A process according to claim 9, wherein the solvent is an alcohol or an alcohol mixture of the formula R ² OH and / or R ⁴ OH, wherein R ² and R ⁴ are as defined. The process of claim 10 wherein R ² is R ⁴ and is methyl or ethyl.