EP1711562A2

EP1711562A2 - Particles having a functional multilayer structure

Info

Publication number: EP1711562A2
Application number: EP05700958A
Authority: EP
Inventors: Alfred Hennemann; Marc Entenmann; Margarete MÜLLER; Renate Bonn-Walter; Adalbert Huber; Ulrich SCHÖNEFELD
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2004-02-07
Filing date: 2005-01-15
Publication date: 2006-10-18
Also published as: DE102004006145A1; CN1918247A; TW200600552A; US7745003B2; US20070166544A1; JP2007525572A; BRPI0507503A; WO2005075578A2; WO2005075578A3; CN1918247B; KR20060122909A

Abstract

The invention relates to particles having a functional multilayer structure based on substrates, and is characterised in that the substrates are coated with at least one layer consisting of at least one polymer, and at least one layer consisting of at least one silane. The invention also relates to methods for the production of said particles and to the use of the same.

Description

Particles with a functional multilayer structure

The present invention relates to particles with a functional multilayer structure based on substrates, characterized in that the substrates are coated with one or more layers of one or more polymers and one or more layers of one or more silanes, processes for their preparation and their use ,

Particulate materials are increasingly being used in a number of technical systems and materials, which can take on a variety of tasks in these systems. For example, they are used for corrosion protection, as a barrier, for mechanical reinforcement but also for coloring. The particulate materials are used in a variety of different ways

Application media used, such as Varnishes, paints, plastics, whereby the particulate materials have their own individual requirements. Primarily, the materials should be well compatible with the surrounding application medium, but must also be sufficiently stable for long periods. For example, platelet-shaped effect pigments based on platelet-shaped substrates are used in many ways for coloring, and in a whole series of application media that differ greatly from the composition. A fundamental problem here is the tendency of platelet-shaped effect pigments to form agglomerates, in which the pigments lie in a stack-like manner and are difficult to separate again owing to strong adhesion. This is all the more serious since, when flake-like effect pigments are incorporated into application media, high shear forces must not be exerted because of the fragility of the thin flakes. The

Compatibility of the particulate materials with the application media is not only problematic with platelet-shaped materials, but also with any particulate materials.

In order to circumvent these problems, it has been proposed many times to subject the particulate materials to a post-treatment that the

Application properties of these materials should improve. The aftertreatment is often a coating of the particulate materials with silanes or polymers. For example, WO 99/51690 describes pigments with improved dispersing properties, one pigment, e.g. Graphite, coated with polyamides, polycarbonates, polyethers etc., and the use of these surface-modified pigments in inks, toners and plastics.

EP 0 703 192 describes crosslinked resin-coated SiO ₂ particles comprising 0.6 to 17 μm-sized SiO ₂ particles which are coated with a vinyl-containing silane in order to then radically polymerize a vinyl monomer to form a polymer. Particles coated in this way serve as a means of controlling the thickness of a liquid crystal layer in an LCD display. The coating therefore serves the sole purpose of ensuring that the particles function as a spacer, ie dispersion of these particles in the liquid-crystal medium is in no way desired. These particles are therefore unsuitable for use in paints, varnishes or plastics because they do not have sufficient dispersibility in these media.

The methods described for surface modification of particles, for example the precipitation polymerization of a monomeric compound in the presence of the particles to be coated or the polymerisation of a monomer onto a functionalized surface, the so-called grafting-from methods (see EP 0 703 192) often fail due to insufficient bonding of the occupancy material on one already modified, eg silane-coated surface, on the necessary, complex functionalization of the surface or on the special requirements when carrying out the reaction, such as, for example, polymerization under a protective gas atmosphere. Furthermore, the layer sequence is often not freely selectable, that is to say the layer sequence cannot be adapted to the requirements but has to be adapted to the process parameters. The essential step is often not the silane modification, but the coating of the surface with polymers.

It was therefore the task of modifying particulate materials in such a way that they can be dispersed in a large number of different media and applications, or their application properties can be individually adapted to the application medium. In addition, the modified particles in the application media should be stable and, in particular in the case of pigments, should lead to a uniform coloring without changing the essential color properties or the gloss. Furthermore, additional stabilization of the particulate materials, in particular in the case of platelet-shaped materials, is desired in order to enable their problem-free use even in applications with high mechanical or thermal loads.

It has been shown that particles with a multilayer structure according to the present invention meet this complex requirement profile and thus expand the area of use of particulate materials even in mechanically or thermally demanding or difficult to apply applications.

The present invention accordingly relates to particles with a multilayer structure based on substrates, the substrates being coated with one or more layers of one or more polymers and one or more layers of one or more silanes are. The present invention furthermore relates to processes for the production of these pigments and their use in paints, water-based paints, powder coatings, paints, printing inks, security elements, plastics, concrete, in cosmetic formulations, in agricultural films and tarpaulins and for the production of pigment preparations and

Dry preparations.

The particles according to the invention with a multilayer structure have the advantage that they can be individually adapted to the application medium with regard to their application properties. The layers of one or more silanes perform a barrier function, the one or more polymer layers stabilize the particles against agglomeration but also against mechanical influences. Depending on the choice of the polymers, the compatibility of the particles with a matrix also consisting of polymers, for example with a binder matrix, is significantly increased. The multilayer structure proves to be stable, which means that the applied layers of silanes and polymers are not detached. It is advantageous here that a chemical linkage of the silanes to the polymers, as is the case in the prior art, is not necessary, that is to say that the silane and the polymer do not have to be coordinated with one another in terms of their structure and reactivity , This extends the variability with regard to the desired properties of the particles and permits the optimal combination of the properties of the silanes used with those of the polymers used. If the polymer layers are not formed by polymerization, but rather, as in the present invention, are preferably produced by precipitation of polymers, then a complex protective gas atmosphere can also be dispensed with. In addition, the process also exposes the particles to fewer foreign substances. The products obtained are thus obtained in a purer form during production, so that a disruptive monomer content or complex cleaning can be avoided here. The particles according to the invention with a multilayer structure are based on substrates, wherein the substrates can in principle have any shape, preferably they are platelet-shaped. In particular, platelet-shaped particles are mechanically loaded by shear forces when incorporated into applications. These particles can be additionally stabilized by the layer structure of silanes and polymers according to the invention, which enables their use in mechanically demanding applications.

Suitable substrates are SiO ₂ , TiO ₂ particles, effect pigments, holographic pigments, pearlescent pigments, interference pigments, multi-layer pigments, metal effect pigments and / or BiOCI pigments, the substrates are preferably effect pigments, pearlescent pigments or metal layer pigments, interference pigments.

Effect pigments, pearlescent pigments, interference pigments, metallic effect pigments or multilayer pigments which can be used according to the present invention are based in particular on carriers, the latter preferably being platelet-shaped. For example, platelet-shaped T1O ₂ , synthetic or natural mica, glass platelets, metal platelets, platelet-shaped SiO ₂ , Al ₂ O ₃ or platelet-shaped iron oxide are suitable. The metal platelets can consist of aluminum, titanium, bronze, steel or silver, preferably aluminum and / or titanium. The metal platelets can be passivated by appropriate treatment. In a preferred embodiment, the support is coated with one or more transparent, semi-transparent and / or opaque layers containing metal oxides, metal oxide hydrates, metal suboxides, metals, metal fluorides, metal nitrides, metal oxynitrides or mixtures of these materials. The metal oxide, metal oxide hydrate, metal suboxide, metal, metal fluoride, Metal nitride, metal oxynitride layers or the mixtures thereof can be low (refractive index <1.8) or high refractive index (refractive index> 1.8). Suitable metal oxides and metal oxide hydrates are all metal oxides or metal oxide hydrates known to the person skilled in the art, such as, for. B. aluminum oxide, aluminum oxide hydrate, silicon oxide, silicon oxide hydrate, iron oxide, tin oxide,

Cerium oxide, zinc oxide, zirconium oxide, chromium oxide, titanium oxide, in particular titanium dioxide, titanium oxide hydrate and mixtures thereof, such as e.g. Ilmenite or pseudobrookite. For example, the titanium suboxides can be used as metal suboxides. Suitable metals are e.g. Chromium, aluminum, nickel, silver, gold, titanium, copper or alloys, as

Metal fluoride is suitable, for example, magnesium fluoride. For example, the nitrides or oxynitrides of the metals titanium, zirconium and / or tantalum can be used as metal nitrides or metal oxynitrides. Metal oxide, metal, metal fluoride and / or metal oxide hydrate layers are preferred, and metal oxide and / or are very particularly preferred

Metal oxide hydrate layers applied to the carrier. Furthermore, multilayer structures made of high and low refractive metal oxide, metal oxide hydrate, metal or metal fluoride layers can also be present, with high and low refractive layers alternating. Layer packages consisting of a high and a low refractive index layer are particularly preferred, it being possible for one or more of these layer packages to be applied to the support. The order of the high and low refractive index layers can be adapted to the carrier in order to include the carrier in the multilayer structure. In a further embodiment, the metal oxide, metal oxide hydrate, metal suboxide, metal, metal fluoride, metal nitride, metal oxynitride layers can be mixed or doped with colorants or other elements. Suitable colorants or other elements are, for example, organic or inorganic color pigments such as colored metal oxides, e.g. Magnetite, chromium oxide or color pigments such as Berlin blue, ultramarine,

Bismuth vanadate, thenards blue, or organic color pigments such as indigo, azo pigments, phthalocyanines or carmine red or Elements such as yttrium or antimony. Effect pigments containing these layers show a wide variety of colors in relation to their body color and in many cases can show an angle-dependent change in color (color flop) due to interference.

In a preferred embodiment, the outer layer on the carrier is a high-index metal oxide. This outer layer can additionally be part of a layer package on the above-mentioned layer packages or in the case of high-index supports and, for example, of TiO ₂ , titanium suboxides, Fe ₂ O ₃ , SnO ₂ , ZnO, ZrO ₂ , Ce ₂ O ₃ , CoO, Co ₃ O ₄ , V ₂ O ₅ , Cr ₂ O ₃ and / or mixtures thereof, such as, for example, llmenite or pseudobrookite. TiO ₂ is particularly preferred.

Examples and embodiments of the above-mentioned materials and pigment structures can be found e.g. also in Research Disclosures RD 471001 and RD 472005, the disclosures of which are hereby incorporated by reference.

The thickness of the metal oxide, metal oxide hydrate, metal suboxide, metal, metal fluoride, metal nitride, metal oxynitride layers or a mixture thereof is usually 3 to 300 nm and in the case of metal oxide, metal oxide hydrate, metal suboxide, metal fluoride, Metal nitride, metal oxynitride layers or a mixture thereof preferably 20 to 200 nm. The thickness of the metal layers is preferably 4 to 50 nm.

The size of the carriers and thus the effect pigments is not critical in itself. Platelet-shaped carriers and / or platelet-shaped carriers coated with one or more transparent, semi-transparent and / or opaque layers generally have a thickness between 0.05 and 5 μm, in particular between 0.1 and 4.5 μm. The expansion in length or width is usually between 1 and 250 μm, preferably between 2 and 200 μm and in particular between 2 and 100 μm.

One or more layers of one or more polymers and one or more layers of one or more silanes are applied to the substrates described above. The one or more layers of silanes and polymers are preferably present as alternating layers of silanes and polymers, that is to say the layers of silanes and polymers alternate. If a layer of one or more silanes is first applied to the substrate, a layer of one or more polymers is preferably subsequently applied, and vice versa. This mutual structure can exist several times in succession, whereby both an odd and an even number of layers can be present, e.g. two, three, four, five, six layers or a multiple thereof. The order can be adjusted as required. There is preferably a structure in which the substrate is coated with a layer of one or more polymers and a layer of one or more silanes applied thereon, or the substrate with a layer of one or more silanes and a layer of one or more polymers applied thereon is coated. In total, therefore, exactly one layer of one or more silanes and one layer of one or more polymers are preferably applied to the substrate.

The one or more polymers can be selected from the group of polyethers, polyacrylates, polyvinyl caprolactams, cellulose, polystyrenes, polyvinyl alcohols, polyvinyl acetates, polysiloxanes, derivatives of the polymers mentioned or from mixtures thereof. The polymers are preferably LCST and / or UCST polymers or polymers with solvolysable groups. LCST polymers or UCST polymers

Polymers which are soluble in a solvent at low or high temperatures and when the temperature is increased or decreased and Reaching the so-called LCST or UCST (lower or upper critical solution temperature) from the solution as a separate phase. Such polymers are described, for example, in the literature in "Polymers", HG Elias, Hüthig and Wepf-Verlag, Zug, 1996 on pages 183 ff. In the case of the polymers with solvolysable groups, these are split off during solvolysis, the polymer on the Substrate fails.

Suitable LCST polymers for the present invention are, for example, those as described in WO 01/60926 and WO 03/014229. Particularly suitable LCST polymers are polyalkylene oxide derivatives, preferably polyethylene oxide (PEO) derivatives, polypropylene oxide (PPO) derivatives, olefinically modified PPO-PEO block copolymers, acrylate-modified PEO-PPO-PEO three-block copolymers, and also polymers or their derivatives from the class of

Polymethyl vinyl ether, poly-N-vinyl caprolactams, ethyl (hydroxyethyl) cellulose, poly (N-isopropylacrylamide) and polysiloxanes. Particularly preferred LCST polymers are siloxane polymers or polyethers modified with olefinic or silanolic groups.

Suitable UCST polymers are in particular polystyrene, polystyrene copolymers and polyethylene oxide copolymers.

LCST or UCST polymers with solvolysable or functional groups that have strong interactions and / or chemical bonds with the substrate or the application medium, such as e.g. the lacquer matrix. All functional groups known to the person skilled in the art are suitable, in particular silanol, amino, hydroxyl, olefin, hydroxyl, epoxy, acid anhydride and acid groups.

The LCST or UCST polymers preferably have molar masses in the range from 300 to 500,000 g / mol, in particular from 500 to 20,000 g / mol. The one or more polymer layers can additionally also contain additives which additionally increase or decrease the chemical and / or mechanical stability of the particles or give the particles UV-filtering properties or a coloring effect. suitable

Additives are e.g. All kinds of nanoparticles, plasticizers, antioxidants, radical scavengers, UV filters, dyes, microtitans or their mixtures. The additives are preferably mixed into the solution of the polymer as a dispersion, the same solvent as that of the polymer solution preferably being used. By including

Foreign substances, e.g. Nanoparticles, plasticizers or dyes, the properties of the particles can be adapted to the individual needs of the user, or several functionalities, such as Coloring and UV filter can be combined in one type of particle.

Another essential component of the particles according to the invention are the one or more layers of one or more silanes. Organosilanes of the general formula are suitable as silanes

X .n-mZ-R _n (-BY) m

with X = OH, halogen, alkoxy, aryloxy

Z = Si R = alkyl, phenyl or hydrogen

B = organic, at least bifunctional group (alkylene,

alkyleneoxyalkylene)

Y = alkyl, amino, substituted amino, hydroxy, hydroxyalkyl, siloxane,

Acetoxy, isocyanate, vinyl, acryloyl, epoxy, epoxypropyloxy, imidazole or ureido group n, m = 0.1, 2.3 with n + m <3 exist. The organosilanes consist of an anchor group (X _4-nm Z), which can bind to the surface of the substrate, at least one hydrophobic group (R, B) and one or more alkyl or functional groups (Y). The anchor group preferably consists of alkoxysilanes which can be converted into corresponding hydroxyl groups by hydrolytic reaction conditions. In the case of the embodiment according to the invention, in which first a silane layer and subsequently a polymer layer is applied to the substrate, the latter can bind, for example, to a calcined metal oxide surface of the substrate and effect the anchoring via oxygen bridges.

By choosing suitable functional groups, the organosilane can be adapted to the requirements. In addition, depending on the coating sequence, reaction of the functional groups with corresponding functionalities in the application media can produce additional bonds between the particles and the medium via the organosilane. In a particular embodiment, the surface of the particles according to the invention is modified with a combination of organic functionalities adapted to the feed medium. The use of mixtures of different organosilanes is also suitable for this. The hydrophobicity of the particle surface can be improved by integrating alkyl-containing coupling reagents, e.g. Alkylsilanes, can also be adjusted. In addition to the organosilanes, the use of their hydrolyzates and their homogeneous and heterogeneous oligomers and / or polymers is also preferred, which can likewise be used alone or in combination with the silanes already described. Mixtures of different organosilanes, in particular with functional groups Y which differ from one another, are particularly preferred, the use of which ensures a particular range of applications.

Examples of organosilanes are propyltrimethoxysilane, propyltriethoxysilane, isobutyltrimethoxysilane, n-octyltrimethoxysilane, i-octyltrimethoxysilane, n- Octyltriethoxysilane, n-decyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, vinyltrimethoxysilane, octadecyltrimethoxysilane, preferably vinyltrimethoxysilane. Suitable oligomeric, alcohol-free organosilane are, among others, those sold under the trade name "Dynasylan ^®" by the company. Sivento products, such. As Dynasylan HS 2926, Dynasylan HS 2909, Dynasylan HS2907, Dynasylan HS 2781, Dynasylan HS 2776, Dynasylan HS 2627. In addition, oligomeric vinylsilane and aminosilane hydrolyzate are suitable as organic coatings, such as 3-aminopropyltrimethoxysilane, 3-

Methacryloxytrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, beta (3,4-epoxycyclohexyl) ethyltrimethoxysilane, gamma-isocyanatopropyltrimethoxysilane, 1, 3-bis (3-glycidoxypropyl) -1, 1, 3,3, -tetramethylreoxysiloxane 3-aminopropyltrimethoxysilane, 3-methacryloxytrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, beta- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, gamma-isocyanatopropyltrimethoxysilane. Examples of polymeric silane systems are described in WO 98/13426 and are described, for. B. from Sivento under the trademark Hydrosil ^® .

The present invention furthermore relates to processes for producing the particles according to the invention, substrates being coated with one or more layers of one or more polymers and one or more layers of one or more silanes.

Coating with one or more layers of one or more polymers is preferably carried out by precipitation in water and / or organic solvents, by polycondensation reactions, by polyaddition reactions and / or by radical polymerization. Precipitation of the polymers is particularly preferred, that is to say the use of polymer precipitation processes. Notably here are said to be preferred polymer precipitation methods for surface modification of particles are called the Lower Critical Solution Temperature, the Upper Critical Solution Temperature and the Solvolysis technology. These processes have the advantage that they are simple in terms of process engineering on the one hand, and insensitive to the type and functionality of the surface on the other. These processes are characterized by the simplicity of their use, since pre-made polymers are already used. This makes a multilayer structure with several alternating silane and polymer layers practicable in the first place, which becomes more difficult with precipitation layers and grafting from methods due to the complexity with each new layer. The amounts of unused monomers which are produced in the latter process and which represent a highly undesirable impurity since they are chemically active and can additionally negatively influence physical parameters such as the hardness and elasticity of a polymer matrix can also be reduced.

In a preferred embodiment of the method according to the invention, the substrate is mixed with an LCST and / or UCST polymer or polymers with solvolysable groups or a polymer mixture, optionally in the presence of a solvent. The LCST polymer is dissolved at a temperature below the LCST, while the UCST polymer is dissolved at a temperature above the UCST. As a rule, the LCST temperature is 0.5 to 90 ° C., preferably 35 to 80 ° C., while the UCST temperature is 5 to 90 ° C., in particular 35 to 60 ° C. Then, if necessary, additives are added. The temperature is then raised, generally by about 5 ° C., via the LCST or lowered below the UCST, the polymer precipitating and settling on the particle surface. Finally, immobilization takes place in the form of a crosslinking of the polymer on the particle surface, the polymer being irreversibly fixed on the particle surface. The immobilization can be radical, cationic, anionic or by Condensation reactions take place. The LCST or UCST polymers are preferably crosslinked by free radicals or by condensation reactions.

For a radical networking (immobilization) of the separated

Layer in water is preferably potassium peroxodisulfate or ammonium peroxodisulfate in concentration ranges from 1 to 100% by weight, based on the olefinic LCST or UCST polymer used for the coating. The crosslinking takes place depending on the LCST or UCST temperature of the polymer at 0 to 35 ° C below

Use of a catalyst, e.g. of an Fe (II) salt, or at 40 to 100 ° C by direct thermal decomposition of the radical initiator.

The thickness of the polymer layers is usually in the range from 2 to 500 nm, preferably from 5 to 300 nm and in particular from 5 to 200 nm.

If a solvent is required in the process according to the invention, the choice of solvent depends on the solubility of the polymer used. The solvent is preferably water or a water-miscible organic solvent. The water-miscible solvents also include those solvents which have gaps in the mixture with water. In these cases, the proportions are chosen so that there is miscibility. Examples of suitable solvents are mono- and polyalcohols, e.g. Methanol, ethanol, n-propanol, isopropanol, glycol, glycerin, propylene glycol, polyethylene glycol, polybutylene glycol as well as the mono- and diether with methanol, ethanol, propanol and butanol of the polyalkylene glycols, as well as ethers, e.g. Tetrahydrofuran, dioxane, 1, 2-propanediol propyl ether, 1, 2-butane-1-methyl ether, ethylene glycol monomethyl ether,

Diethylene glycol monomethyl ether. Esters, such as methyl acetate, monoesters of ethylene glycol or propylene glycol, are also suitable with acetic acid, butyrolactone, but also ketones, such as, for example, acetone or methyl ethyl ketone or amides, such as, for example, formamide, dimethylformamide, dimethylacetamine, N-methylpyrrolidone and hexamethylphosphoric acid triamide, or sulfoxides and sulfones, such as dimethyl sulfoxide and sulfolane, and alkane carboxylic acids or acetic acid such as formic acid. Preferred solvents are water and alcohols or glycols.

If the application of one or more silanes preferably by precipitation in solution at temperatures above 60 ^C C, preferably above 70 ° C. Methods of this type are known to the person skilled in the art and are described, for example, in WO 98/13426, EP 0 416 395, EP 0 679 700, EP 0 634 459 or EP 0 268 918, the disclosures of which are hereby incorporated by reference. Organic solvents, water or mixtures thereof are suitable as solvents; water is preferably used. The reaction time required for applying the organic coating is at least 5 minutes, preferably over a period of 10 to 90 minutes, but can also be extended as desired. The particles obtained are worked up and isolated by methods customary for the person skilled in the art, for example by filtration, drying and sieving.

Another object of the present invention is the use of the particles according to the invention in paints, water-based paints, powder coatings, paints, printing inks, toners, security elements, plastics, concrete, in cosmetic formulations, in agricultural films and tarpaulins and for the production of pigment preparations and dry preparations.

In the case of cosmetics, the particles according to the invention are particularly suitable for products and formulations of decorative cosmetics, such as, for example, nail polishes, coloring powders, lipsticks or eye shadows, soaps, toothpastes, etc. Of course, the particles according to the invention Particles in the formulations can also be combined with any type of cosmetic raw materials and auxiliaries. These include oils, fats, waxes, film formers, preservatives and auxiliary substances that generally determine application properties, such as thickeners and rheological additives such as bentonites, hectorites, silicon dioxide, calcium

Silicates, gelatin, high molecular weight carbohydrates and / or surface-active auxiliaries, etc. The formulations containing particles according to the invention can be of the lipophilic, hydrophilic or hydrophobic type. In heterogeneous formulations with discrete aqueous and non-aqueous phases, the particles according to the invention can each contain only one of the two phases or can be distributed over both phases.

The pH values of the aqueous formulations can be between 1 and 14, preferably between 2 and 11 and particularly preferably between 5 and 8. There are no limits to the concentrations of the particles according to the invention in the formulation. Depending on the application, they can be between 0.001 (rinse-off products, e.g. shower gels) - 100% (e.g. gloss effect articles for special applications when using effect pigments as a substrate). The particles according to the invention can also be combined with cosmetic active ingredients. Suitable active ingredients are e.g. Insect repellents, UV A / BC protective filters (e.g. OMC, B3, MBC), anti-aging ingredients, vitamins and their derivatives (e.g. vitamins A, C, E etc.), self-tanners (e.g. DHA, erythrolosis etc.) and others cosmetic active ingredients such as Bisabolol, LPO, ectoin, emblica, allantoin, bioflavanoids and their derivatives.

When using the particles in paints and varnishes, all areas of application known to the person skilled in the art are possible, e.g. Powder coatings,

Automotive paints, printing inks for gravure, offset, screen or flexographic printing as well as for paints in outdoor applications. For the production of the Printing inks are suitable for a large number of binders, in particular water-soluble types, for example based on acrylates, methacrylates, polyesters, polyurethanes, nitrocellulose, ethyl cellulose, polyamide, polyvinyl butyrate, phenolic resins, maleic resins, starch or polyvinyl alcohol. The lacquers can be water- or solvent-based lacquers, the selection of the lacquer components being subject to the general knowledge of the person skilled in the art.

In addition, the particles according to the invention can be used in films and plastics, e.g. in agricultural films, infrared reflecting films and disks, gift films, plastic containers and moldings for all applications known to the person skilled in the art. All common plastics are suitable as plastics for incorporating the particles according to the invention, e.g. Thermosetting or thermoplastic. The description of the possible applications and the plastics, processing methods and additives that can be used can be found e.g. in RD 472005 or in R. Glausch, M. Kieser, R. Maisch, G. Pfaff, J. Weitzel, Pearlescent Pigments, Curt R. Vincentz Verlag, 1996, 83 ff., the disclosure content of which is included here.

It has e.g. proved to be advantageous, in the context of the present invention, in the case of platelet-shaped effect pigments as particles for use in liquid coating systems, first covering them with a silane layer which functions as a water barrier layer and then with a polymer layer, the polymer layer being used to stabilize the particles, the mechanical stabilization and the interaction formation with the matrix, preferably a binder matrix. An important criterion for assessing the particles according to the invention is the change in their properties when incorporated into paints. As a

The criterion for the examination is the DOl (Distinctness of Image), which is the sharpness of the side edges of a surface of an object describes the reflected image. In the case of effect pigments in particular, the highest possible level of DOl is desirable in order to achieve a high level of reflectivity and gloss. The particles coated according to the present invention, for example effect pigments, have a high initial value for the DOl when they are incorporated into coating systems and a low DOl drop when exposed to water, for example in the course of a condensation test. Flocculation in the coating medium and aggregation during the drying process are suppressed extremely strongly and the wetting is greatly improved by the outer polymer layer. In general, these particles show a more universal applicability in a wide variety of polymer matrix systems.

For use in systems with higher mechanical loads, the corresponding polymer layer must be adjusted in its thickness compared to the silane layer. Often, e.g. when used in powder coating systems, a certain incompatibility with the coating matrix is desired in order to produce, for example, so-called leafing effects (the floating of pigments on the surface when incorporated in a binder matrix). It can be advantageous here to carry out the layer sequence in the opposite way. A corresponding layer sequence is often also more thermally stable, so that thermally demanding applications of these particles in plastics are also possible. A thick polymer layer, for example, also reduces the separation in the powder coating application, so that the particles according to the invention are preferably used in powder coatings,

Liquid coating systems, plastics and in systems with high mechanical energy input can be used, whereby the layer sequence and composition, as well as the thickness of the individual layers can be specifically adapted to the requirements.

The particles according to the invention with a multilayer structure are also suitable for use in Mixtures with organic dyes and / or pigments, such as transparent and opaque white, colored and black pigments as well as with platelet-shaped iron oxides, organic pigments, holographic pigments, LCPs (Liquid Crystal Polymers) and conventional transparent, colored and black gloss pigments based on metal oxide-coated platelets based on mica, glass, Al2O ₃ , Fβ2θ ₃ , SiO ₂ , etc. The particles according to the invention can be mixed in any ratio with commercially available pigments and fillers.

As fillers e.g. natural and synthetic mica, nylon powder, pure or filled melanin resins, talcum, glasses, kaolin, oxides or hydroxides of aluminum, magnesium, calcium, zinc, BiOCI, barium sulfate, calcium sulfate, calcium carbonate, magnesium carbonate, carbon, as well as physical or chemical combinations of these substances to call. There are no restrictions on the particle shape of the filler. According to e.g. be platelet-shaped, spherical or acicular.

The particles according to the invention are furthermore suitable for the production of flowable pigment preparations and dry preparations containing one or more particles, binders and optionally one or more additives. Dry preparations are also understood to mean preparations which contain 0 to 8% by weight, preferably 2 to 8% by weight, in particular 3 to 6% by weight, of water and / or a solvent or solvent mixture. The dry preparations are preferably in the form of pellets, granules, chips, sausages or briquettes and have particle sizes of 0.2-80 mm. The dry preparations are used in particular in the manufacture of printing inks and in cosmetic formulations. Because of their broad applicability, paints, water-based paints, powder coatings, paints, printing inks, toners, security elements, plastics, concrete, cosmetic formulations, agricultural films, tarpaulins, pigment preparations and dry preparations containing particles with a multilayer structure according to the present invention are also the subject of the present invention.

The following examples are intended to explain the invention in greater detail without, however, limiting it.

Examples:

Example 1 100 g of Iriodin 225 ^® are in 600 ml of distilled water at 75 ° C

Stir heated. 1 g of aminopropyltrimethoxysilane and then 1 g of vinyltrimethoxysilane are slowly added dropwise. After stirring at 75 ° C. for 30 minutes, the mixture is filtered and washed. The pigment is again taken up in 300 ml of water, 1.5% of an olefin-functionalized polypropylene oxide is added dropwise at 20 ° C., heated to 66 ° C. and, after the addition of 1 g of potassium peroxodisulfate, crosslinked radically by stirring at this temperature for 60 minutes. It is filtered off, the post-coated pigment is washed with water and dried in a forced air oven at 130.degree. When incorporated into conventional paint systems and water-based paint systems, the pigment generally has both a high initial value for the DOl and a low DOl drop. It is essential that this pigment can be used universally in a wide variety of coating systems, so that the advantages described occur almost independently of the coating system. Compared to silane-coated effect pigments, this pigment also has increased mechanical stability against shear loads. Example 2:

100 g of Iriodin ^® 103 are stirred in 300 ml of distilled water with 3 g of an amino-functionalized polypropylene oxide (LCST temperature 40 ° C.) at room temperature. It is heated to 45 ° C. and stirred at this temperature for 15 minutes. After further heating to 75 ° C, another 300 ml of distilled water are added. After the slow addition of 0.5 g of aminopropyltrimethoxysilane, 1.5 g of vinyltrimethoxysilane are also slowly added dropwise. After 45 minutes of stirring at 75 ° C., the after-coated effect pigment is filtered off, washed and dried at 130 ° C. in a forced air oven.

Due to its thicker polymer layer, this pigment is suitable for systems with increased mechanical energy input, i.e. also for powder coating applications, since its hydrophobic surface shows excellent leafing and low separation properties during application in many powder coating systems. Due to the thermally stable silane coating as the outermost layer, it can also be used successfully in plastics with high thermal loads.

Claims

claims

1. Particles with a multilayer structure based on substrates, characterized in that the substrates are coated with one or more layers of one or more polymers and one or more layers of one or more silanes.

2. Particle according to claim 1, characterized in that it is an alternating layers of polymers and silanes.

3. Particles according to claim 1 or 2, characterized in that the substrates are coated with a layer of one or more polymers and a layer of one or more silanes applied thereon.

4. Particle according to claim 1 or 2, characterized in that the substrates are coated with a layer of one or more silanes and a layer of one or more polymers applied thereon.

5. Particle according to one of claims 1 to 4, characterized in that the substrates are platelet-shaped.

6. Particle according to one of claims 1 to 5, characterized in that the substrate is selected from the group consisting of SiO ₂ -, TiO _∑ - particles, effect pigments, holographic pigments, pearlescent pigments, interference pigments, multilayer pigments, metallic effect pigments and / or BiOCI pigments ,

7. Particles according to claim 6, characterized in that the effect pigments, holographic pigments, pearlescent pigments, Interference pigments, multilayer pigments and / or metallic effect pigments are based on supports made of natural or synthetic mica, Al ₂ O ₃ , TiO ₂ , SiO ₂ , Fe ₂ O ₃ , glass, ceramic, metal or graphite platelets.

8. Particles according to one of claims 1 to 7, characterized in that the one or more polymers are selected from the group of polyethers, polyacrylates, polyvinyl caprolactams, cellulose, polystyrenes, polyvinyl alcohols, polyvinyl acetates, polysiloxanes, derivatives of the polymers mentioned or from mixtures thereof ,

9. Particle according to one of claims 1 to 8, characterized in that the polymers are LCST and / or UCST polymers or polymers with solvolysable groups.

10. Particle according to one of claims 1 to 9, characterized in that the one or more polymer layers additionally contain additives.

11. Particles according to one of claims 1 to 10, characterized in that one or more silanes are selected from the group of organosilanes with the general formula

X ₄ -n-mZ-R _n (-BY) | m with X = OH, halogen, alkoxy, aryloxy Z = Si R = alkyl, phenyl or hydrogen B = organic, at least bifunctional group (alkylene, alkyleneoxyalkylene) Y = alkyl, amino, substituted amino, hydroxy, hydroxyalkyl, siloxane, acetoxy, isocyanate, vinyl, acryloyl, epoxy, epoxypropyloxy, imidazole or ureido group n, m = 0.1, 2,3 with n + m <3 exist.

12. A method for producing particles with a multilayer structure according to claim 1, characterized in that substrates are coated with one or more layers of one or more polymers and one or more layers of one or more silanes.

13. The method according to claim 12, characterized in that the coating is carried out with one or more polymers by precipitation in water and / or organic solvents, by polycondensation reactions, by polyaddition reactions and / or by radical polymerization.

14. The method according to claim 12 or 13, characterized in that the polymers are LCST and / or UCST polymers or polymers with solvolysable groups.

15. The method according to any one of claims 12 to 14, characterized in that the silanes are applied by precipitation in water and / or organic solvents.

16. Use of particles with multilayer structure according to claim 1 in paints, water-based paints, powder coatings, paints, printing inks, toners, security elements, plastics, concrete, in cosmetic formulations, in agricultural films and tarpaulins and for the production of pigment preparations and dry preparations.

7. paints, water-based paints, powder coatings, paints, printing inks, toners, security elements, plastics, concrete, cosmetic formulations, agricultural films, tarpaulins, pigment preparations and dry preparations containing particles with multilayer structure according to claim 1.