WO2005056621A1

WO2005056621A1 - Effect coloring agents containing core-shell particles

Info

Publication number: WO2005056621A1
Application number: PCT/EP2004/013005
Authority: WO
Inventors: Holger Winkler; Corinna Weigandt; Goetz Peter Hellmann; Tilmann Eberhard Ruhl; Peter Spahn; Benjamin Viel
Original assignee: Merck Patent Gmbh
Priority date: 2003-12-10
Filing date: 2004-11-17
Publication date: 2005-06-23
Also published as: DE10357679A1; TW200602397A

Abstract

The invention relates to effect coloring agents essentially comprised of core-shell particles whose shell forms a matrix and whose core is essentially solid and has an essentially monodispersed size distribution, whereby a difference between the indices of refraction of the core material and of the shell material exists. The invention is characterized in that the matrix is brittle. The invention also relates to methods for producing the effect coloring agents and to the use thereof.

Description

Effect colorant containing core-shell particles

The invention relates to effect colorants containing core-shell particles and to processes for producing the effect colorants and their use.

Natural precious opals are made up of domains, consisting of monodisperse, densely packed and therefore regularly arranged

Silica gel spheres with diameters of 150-400 nm. The play of colors of these opals comes about through Bragg-like scattering of the incident light on the grating planes of the domains arranged in a crystal-like manner.

There has been no shortage of attempts to synthesize white and black opals for jewelry purposes, using water glass or silicone esters as the starting product.

US 4 703 020 describes a method for producing a decorative material which consists of amorphous silica spheres which are arranged three-dimensionally, zirconium oxide or zirconium hydroxide being located in the spaces between the spheres. The beads have a diameter of 150-400 nm. The production takes place in two stages. In a first stage, silica spheres are sedimented from an aqueous suspension. The mass obtained is then dried in air and then calcined at 800 ° C. The calcined material is introduced into the solution of a zirconium alkoxide in a second stage, the alkoxide penetrating into the spaces between the cores and zirconium oxide being precipitated by hydrolysis. This material is then calcined at 1000-1300 ° C.

EP-A-0 955 323 describes core / shell particles, their core and

Shell materials can form a two-phase system and are characterized in that the shell material is filmable and the cores are essentially dimensionally stable under the conditions of the filming of the shell, cannot swell or only to a very small extent through the shell material and have a monodisperse size distribution, with a difference between the refractive indices of the core material and the shell material of at least 0.001. The production of the core / shell particles and their use for the production of moldings are also described. The process for the production of a shaped body comprises the following steps: application of the core / shell particles to a substrate with low adhesion, if necessary allowing to evaporate or

Expelling the solvent or diluent possibly contained in the applied layer, converting the shell material of the core / shell particles into a liquid, soft or visco-elastic matrix phase, orienting the cores of the core / shell particles at least to domains of regular structure, Hardening of the shell material for

Fixation of the regular core structure, detachment of the hardened film from the substrate and, if a pigment or powder is to be produced, shredding of the detached film to the desired particle size. With these core-shell particles disclosed in EP-A-0 955 323, the core "floats" in the shell matrix; a long-range order of the

Nuclei do not form in the melt, but only a short-range order of the nuclei in domains. As a result, these particles are only of limited suitability for processing using methods customary for polymers.

Shaped bodies are known from patent application WO 03/25035, which essentially consist of core-shell particles, the shell of which forms a matrix and whose core is essentially solid and has an essentially monodisperse size distribution, the shell preferably having an intermediate layer is firmly connected to the core. The refractive indices of the core material and the differ

Sheath material, whereby said optical effect, preferably an opalescence. According to patent application DE 10204338, contrast materials, such as pigments, are additionally introduced into moldings of such core-shell particles. The embedded contrast materials cause an increase in the brilliance, contrast and depth of the observed Color effects on these moldings. The processing of such shaped bodies into pigments is also described. The pigments can be produced, for example, by first producing a film from the core-shell particles, which can optionally be hardened. The film can then be suitably cut or cut

Breaking and possibly grinding to give pigments of a suitable size. This process can take place, for example, in a continuous belt process. The pigments obtainable in this way are particularly suitable for use in paints, lacquers, printing inks, plastics, ceramic materials, glasses and cosmetic formulations. The mechanical properties of these moldings or pigments are essentially determined by the shell polymers. Preferred shell polymers are elastomers. The moldings of such preferred embodiments thus necessarily show material properties of elastomers.

For decorative applications it is desirable to be able to provide even large structures with the angle-dependent color effect. It was therefore an object of the present invention to provide effect colorants and preparations comprising the effect colorants which are also suitable for providing large-area structures with a color effect which is dependent on the viewing angle and which have mechanical properties which are highly suitable for production, processing and use.

A first object of the present invention are therefore effect colorants consisting essentially of core-shell particles, the shell of which forms a matrix and whose core is essentially solid and has an essentially monodisperse size distribution, with a difference between the refractive indices of the core material and the

Sheath material exists, which are characterized in that the matrix is brittle. A brittle matrix is understood to mean a matrix which has such a high mechanical hardness that films can be milled with this matrix. In particular, a brittle matrix in the sense of the present invention shows no elastomeric properties and does not flow even under mechanical stress. A brittle matrix in the sense of the present invention breaks when subjected to mechanical stress.

In a preferred embodiment of the present invention, the brittleness of the matrix is achieved in that the

Matrix is essentially formed by cross-linked organic polymers.

In a likewise preferred embodiment of the present invention, the glass transition temperature T _{G of} the matrix is above

25 ° C, preferably above 50 ° C and particularly preferably above 70 ° C, so that under the usual conditions of use of the effect colorant at room temperature or z. B. by solar radiation slightly elevated temperature, the brittleness of the matrix is ensured in the sense mentioned above. The

Glass transition temperature can be set by suitable selection of polymers as the shell material of the core-shell particles. The targeted selection does not cause any problems for the person skilled in the art. The jacket material is particularly preferably homo- or copolymeric poly (cyclohexyl methacrylate), polystyrene and substituted

Polystyrene derivatives, such as. B. poly (iodostyrene) and poly (bromostyrene), polyacrylates and polymethacrylates with a Tg above the temperature of use, high Tg polyvinyl chloride and other vinyl polymers resulting from conversion from polyvinyl acetate, polyacrylonitrile and styrene-acrylonitrile copolymers. Apart from the aspects discussed, the effect colorants according to the invention are made up of core-shell particles, as described in WO 03/25035.

In order to achieve the optical effect according to the invention, it is desirable that the core-shell particles have a medium one

Have particle diameters in the range from about 5 nm to about 2000 nm. It can be particularly preferred if the core-shell particles have an average particle diameter in the range from about 5 to 20 nm, preferably 5 to 10 nm. In this case the nuclei can be called "quantum dots"; they show the corresponding effects known from the literature. To achieve color effects in the visible light range, it is particularly advantageous if the core-shell particles have an average particle diameter in the range of approximately 40-500 nm. Particles in the range from 80 to 500 nm are particularly preferably used, since at

Particles in this order of magnitude, the reflections of different wavelengths of visible light differ significantly from one another and so the opalescence, which is particularly important for optical effects in the visible range, occurs particularly distinctly in a wide variety of colors. In a variant of the present

According to the invention, however, it is also preferred to use multiples of this preferred particle size, which then lead to reflections corresponding to the higher orders and thus to a broad play of colors.

Under an optical effect, both

Effects in the visible wavelength range of light as well as effects in the UV or infrared range are understood. Recently it has become common to refer to such effects as photonic effects. All of these effects are optical effects in the sense of the present invention, with one being preferred

Embodiment in which the effect is an opalescence in the visible range. Act in the sense of a usual definition of the term the effect colorants according to the invention are photonic crystals (cf. Chemistry News; 49 (9) September 2001; pp. 1018-1025).

According to the invention, it is particularly preferred if the core of the core

Jacket particles consist of a material that either does not flow or becomes flowable at a temperature above the flow temperature of the jacket material. This can be achieved by using polymeric materials with a correspondingly high glass transition temperature (T _g ), preferably crosslinked polymers, or by using inorganic ones

Core materials. The suitable materials are described in detail below.

The difference in the refractive indices of the core and the cladding is also decisive for the intensity of the observed effects. invention

Effect colorants preferably have a difference between the refractive indices of the core material and the cladding material of at least 0.001, preferably at least 0.01 and particularly preferably at least 0.1. If the effect colorants according to the invention are to exhibit technically usable photonic effects, then there are

Refractive index differences of at least 1.5 are preferred.

In a special embodiment of the invention, further nanoparticles are embedded in the matrix phase of the effect colorants in addition to the cores of the core-shell particles. These particles are selected with regard to their particle size so that they fit into the cavities of the spherical packing from the cores and so change the arrangement of the cores only slightly. Through the targeted selection of appropriate materials and / or the particle size, it is possible, on the one hand, to change the optical effects of the effect colorants, for example to increase the intensity.

On the other hand, the matrix can be appropriately functionalized by incorporating suitable “quantum dots”. Preferred materials are inorganic nanoparticles, in particular nanoparticles of metals or of II-VI or III-V semiconductors or of materials which influence the magnetic properties of the materials. Examples of preferred nanoparticles are gold, zinc sulfide, hematite or gallium arsenide.

The exact mechanism which leads to the uniform orientation of the core-shell particles in the effect colorants according to the invention has hitherto been unknown. However, it has been shown that the application of force is essential for the formation of the far-reaching order. It is believed that the elasticity of the jacket material among the

Processing conditions is crucial for the ordering process. The chain ends of the shell polymers generally have the tendency to assume the shape of a coil. If two particles come too close, the balls are compressed according to the model and repulsive forces arise. Since the shell polymer chains of different particles also interact with each other, the polymer chains are stretched according to the model if two particles move away from each other. The effort of the sheath polymer chains to resume a ball shape creates a force that pulls the particles closer together again. After the model presentation, the far-reaching order of the

Particles in the effect colorant generated by the interplay of these forces.

Core-shell particles whose shell is connected to the core via an intermediate layer have proven to be particularly well suited for the production of effect colorants according to the invention.

In a preferred embodiment, the shell of this core-shell particle consists of organic polymers which are preferably grafted onto the core via an at least partially cross-linked intermediate layer. The core can consist of various materials. It is essential according to the invention, as already stated, that there is a refractive index difference from the cladding and that the core remains solid under the processing conditions.

Furthermore, in a variant of the invention, it is particularly preferred if the core consists of an organic polymer, which is preferably crosslinked.

In another likewise preferred variant of the invention, the

Core made of an inorganic material, preferably a metal or semi-metal or a metal chalcogenide or metal pnictide. For the purposes of the present invention, chalcogenides are compounds in which an element of the 16th group of the periodic table is the electronegative binding partner; as pnictide those in which an element of the 15th group of the periodic table is the electronegative binding partner.

Preferred cores consist of metal chalcogenides, preferably metal oxides, or metal pnictides, preferably nitrides or phosphides. Metal in the sense of these terms are all elements that can appear as electropositive partners in comparison to the counterions, such as the classic metals of the subgroups or the main group metals of the first and second main groups, but also all elements of the third main group and silicon,

Germanium, tin, lead, phosphorus, arsenic, antimony and bismuth. The preferred metal chalcogenides and metal pnictides include in particular silicon dioxide, aluminum oxide, gallium nitride, boron and aluminum nitride as well as silicon and phosphorus nitride.

In a variant of the present invention, the starting material for the production of the core-shell particles according to the invention preferably monodisperse cores made of silicon dioxide are used, which can be obtained, for example, by the process described in US Pat. No. 4,911,903. The cores are produced by hydrolytic polycondensation of tetraalkoxysilanes in an aqueous ammoniacal medium, with a sol of

Primary particles produced and then brought the SiO ₂ particles obtained to the desired particle size by continuous, controlled metering of tetraaikoxysilane. This process can be used to produce monodisperse Si0 ₂ cores with average particle diameters between 0.05 and 10 μm with a standard deviation of 5%.

Also preferred as the starting material are Si0 ₂ cores which are coated with (semi) metals or non-absorbent metal oxides, such as Ti0 ₂ , Zr0 ₂ , Zn0 ₂ , Sn0 ₂ or Al ₂ 0 ₃ . The production of SiO ₂ cores coated with metal oxides is described, for example, in US Pat. No. 5,846,310.

DE 19842 134 and DE 199 29 109 described in more detail.

Monodisperse cores made of non-absorbent metal oxides such as Ti0 ₂ , Zr0 _2> Zn0 ₂ , Sn0 ₂ or Al ₂ 0 ₃ or metal oxide mixtures can also be used as the starting material. Their manufacture is, for example, in

EP 0 644 914. Furthermore, the method according to EP 0 216 278 for producing monodisperse Si0 ₂ cores can be transferred to other oxides without further notice and with the same result. Tetraethoxysilane, tetrabutoxytitanium, tetrapropoxyzirconium or their mixtures are added in one pour with vigorous mixing to a mixture of alcohol, water and ammonia, the temperature of which is adjusted to 30 to 40 ° C. with a thermostat, and the mixture obtained for a further 20 Vigorously stirred for seconds, forming a suspension of monodisperse nuclei in the nanometer range. After a reaction time of 1 to 2 hours, the

Cores are separated, washed and dried in the usual way, for example by centrifugation. Furthermore, monodisperse cores made of polymers which contain particles, for example metal oxides, are also suitable as the starting material for the production of the core-shell particles according to the invention. Such materials are offered for example by the company micro caps Entwicklungs- und Vertriebs GmbH in Rostock. Micro-encapsulations based on polyester, polyamides and natural and modified carbohydrates are manufactured according to customer-specific requirements.

Monodisperse cores made of metal oxides which are coated with organic materials, for example silanes, can also be used. The monodisperse cores are dispersed in alcohols and modified with common organoalkoxysilanes. The silanization of spherical oxide particles is also described in DE 43 16 814.

The cores of the core-shell particles according to the invention can also contain dyes, for example so-called nanocolorants, as described for example in WO 99/40123, can be used. The disclosure of WO 99/40123 is hereby expressly included in the disclosure of the present application.

For the intended use of the core / shell particles according to the invention for the production of effect colorants, it is important that

Sheath material is filmable, ie that it can be softened, plasticized or liquefied visco-elastically by simple measures to such an extent that the cores of the core / sheath particles can at least form domains of a regular arrangement. The nuclei which are regularly arranged in the matrix formed by filming the cladding of the core / cladding particles form a diffraction grating which causes interference effects and thus leads to very interesting color effects. The materials of the core and shell can, provided they meet the conditions specified above, have an inorganic, organic or even metallic character or they can be hybrid materials.

In view of the possibility of varying the properties of the cores of the core / shell particles according to the invention as required, however, it is expedient that the cores contain one or more polymers and / or copolymers (core polymers) or that they consist of such polymers consist.

The cores preferably contain a single polymer or copolymer. For the same reason, it is expedient that the shell of the core / shell particles according to the invention also contains one or more polymers and / or copolymers (shell polymers; matrix polymers) or polymer precursors and, if appropriate, auxiliaries and additives, the

Composition of the jacket can be chosen so that it is essentially dimensionally stable and non-tacky in a non-swelling environment at room temperature.

With the use of polymer substances as a jacket material and possibly

Nuclear material gives the skilled worker the freedom of their relevant properties, such as. B. their composition, the particle size, the mechanical data, the refractive index, the glass transition temperature, the melting point and the weight ratio of core: shell and thus also determine the application properties of the core / shell particles, which ultimately also depend on the properties of the resulting effect colorants produced.

Polymers and / or copolymers which can be contained in the core material or of which it consists, are high molecular weight compounds which correspond to the specification given above for the core material. Both polymers and copolymers of polymerizable unsaturated monomers are suitable, as are polykonensates and copolycondensates of monomers with at least two reactive groups, such as, for. B. high molecular weight aliphatic, aliphatic / aromatic or fully aromatic

Polyesters, polyamides, polycarbonates, polyureas and polyurethanes, but also aminoplast and phenoplast resins, such as. B. melamine / formaldehyde, urea / formaldehyde and phenol / formaldehyde condensates.

For the production of epoxy resins which are also suitable as core material, epoxy prepolymers are usually used, for example by reaction of bisphenol A or other bisphenols, resorein, hydroquinone, hexanediol or other aromatic or aliphatic diols or polyols or phenol-formaldehyde condensates or mixtures thereof with epichlorohydrin or other di- or

Polyepoxides are obtained, mixed with other compounds capable of condensation directly or in solution and allowed to harden.

In a preferred variant of the invention, the polymers of the core material are expediently crosslinked (co) polymers, since these usually only show their glass transition at high temperatures.

These crosslinked polymers can either already in the course of

Polymerization or polycondensation or copolymerization or

Copolycondensation have been crosslinked or, after the actual (co) polymerization or (co) polycondensation has ended, they can have been crosslinked in a separate process step.

For the shell material, as for the core material, in principle polymers of the classes already mentioned are suitable, provided that they are selected or constructed in such a way that they correspond to the specification given above for the shell polymers.

Polymers that meet the specifications for a sheath material can also be found in the groups of polymers and copolymers of polymerizable unsaturated monomers and in the polycondensates and copolycondensates of monomers with at least two reactive groups, such as, for. B. the high molecular weight aliphatic, aliphatic / aromatic or fully aromatic polyesters and polyamides.

Taking into account the above conditions for the properties of the

Shell polymers (= matrix polymers) are in principle for their production selected building blocks from all groups of organic film formers. In particular, if the matrix of the effect colorant is to be formed from crosslinked organic polymers, the choice of the shell polymers can be made almost arbitrarily. It only has to be ensured that these polymers can be provided with crosslinkable groups.

Some other examples may illustrate the wide range of polymers suitable for making the sheath.

If the sheath is to have a comparatively low refractive index, polymers such as polyethylene, polypropylene, polyethylene oxide, polyacrylates, polymethacrylates, polybutadiene, polymethyl methacrylate, polytetrafluoroethylene, polyoxymethylene, polyesters, polyamides, polyepoxides, polyurethane, rubber, polyacrylonitrile and, for example, are suitable

Polyisoprene.

If the sheath is to be comparatively high-index, then, for example, polymers with a preferably aromatic basic structure such as polystyrene, polystyrene copolymers such as. B. SAN, aromatic-aliphatic polyesters and polyamides, aromatic polysulfones and polyketones, polyvinyl chloride, polyvinylidene chloride and, with suitable selection of a high-index core material, also polyacrylonitrile or polyurethane.

In a particularly preferred embodiment of core-shell particles according to the invention, the core consists of crosslinked polystyrene and the shell consists of a polyacrylate, preferably polyethyl acrylate and / or polymethyl methacrylate, to which crosslinkable monomers have been added.

With regard to the processability of the core-shell particles to effect colorants, it is advantageous if the weight ratio of core to shell is in the range from 2: 1 to 1: 5, preferably in the range from 3: 2 to 1: 3 and particularly preferably is in the range of 1: 1 to 2: 3. As a general rule it applies here that it is advantageous to increase the proportion of the jacket if the particle diameter of the cores increases.

The core-shell particles to be used according to the invention can be produced by various processes. A preferred possibility of obtaining the particles is a process for the production of core-shell particles, by a) surface treatment of monodisperse cores, and b) application of the shell from organic polymers to the treated cores.

In one process variant, the monodisperse cores are obtained in a step a1) by emulsion polymerization.

In a preferred variant of the invention, a crosslinked polymeric intermediate layer is preferably applied to the cores in step a)

Emulsion polymerization or by ATR polymerization applied, which preferably has reactive centers to which the jacket can be covalently attached. ATR-Polymerization stands here for Atomic Transfer Radicalic Polymerization, as for example in K. Matyjaszewski, Practical Atom Transfer Radical Polymerization, Polym.

Mater. Be. Closely. 2001, 84. Encapsulation of inorganic materials using ATRP is described, for example, in T. Werne, TE Patten, Atom Transfer Radical Polymerization from Nanoparticles: A Tool for the Preparation of Well-Defined Hybrid Nanostructures and for Understanding the Chemistry of Controlled / "Living" Radical Polymerization from Surfaces, J. Am. Chem. Soc. 2001, 123, 7497-7505 and WO 00/11043. The implementation of both this method and the implementation of emulsion polymerizations are familiar to the person skilled in the art of polymer production and are described, for example, in the abovementioned references. The liquid reaction medium in which the polymerizations or copolymerizations can be carried out consists of the solvents, dispersants or diluents customarily used in polymerizations, in particular in processes of emulsion polymerization. This is done in such a way that the emulsifiers used to homogenize the core particles and shell precursors can develop sufficient effectiveness. Aqueous media, in particular water, are favorable as the liquid reaction medium for carrying out the process according to the invention.

For initiating the polymerization, for example, polymerization initiators are suitable which either decompose thermally or photochemically, form free radicals and thus initiate the polymerization. Among the thermally activatable polymerization initiators, preference is given to those between 20 and 180 ° C., in particular between 20 and 80

° C disintegrate. Particularly preferred polymerization initiators are peroxides such as dibenzoyl peroxide, di-tert-butyl peroxide, peresters, percarbonates, perketals, hydroperoxides, but also inorganic peroxides such as H2O2, salts of peroxosulfuric acid and peroxodisulfuric acid, azo compounds, boralkyl compounds and homolytically disintegrating

Hydrocarbons. The initiators and / or photoinitiators, which, depending on the requirements of the polymerized material, are used in amounts between 0.01 and 15% by weight, based on the polymerizable components, can be used individually or in combination with one another to take advantage of advantageous synergistic effects be applied.

Redox systems are also used, e.g. Salts of peroxodisulfuric acid and peroxosulfuric acid in combination with low-valent sulfur compounds, in particular ammonium peroxodisulfate in combination with sodium dithionite.

Appropriate processes have also been described for the production of polycondensation products. So it is possible that To disperse starting materials for the production of polycondensation products in inert liquids and, preferably with low molecular weight reaction products such as water or - z. B. when using dicarboxylic acid di-lower alkyl esters for the production of polyester or polyamides - lower alkanols to condense.

Polyaddition products are obtained analogously by reaction with compounds which have at least two, preferably three reactive groups, such as, for. B. epoxy, cyanate, isocyanate, or isothiocyanate groups, with compounds that carry complementary reactive groups.

For example, isocyanates react with alcohols to form urethanes, with amines to form urea derivatives, while epoxides react with these complementaries to form hydroxyethers or hydroxyamines. Like the polycondensation reactions, polyaddition reactions can advantageously also be carried out in an inert solvent or dispersant.

It is also possible to use aromatic, aliphatic or mixed aromatic-aliphatic polymers, e.g. As polyesters, polyurethanes, polyamides, polyureas, polyepoxides or solution polymers, in a dispersant such as. B. in water, alcohols, tetrahydrofuran,

To disperse or emulsify hydrocarbons (secondary dispersion) and to condense, crosslink and cure in this fine distribution.

For the preparation of these for polymerization-polycondensation or

Polyaddition processes required stable dispersions are usually used dispersing aids.

As dispersants, preferably water-soluble high molecular weight organic compounds with polar groups, such as

Polyvinyl pyrrolidone, copolymers of vinyl propionate or acetate and

Vinypyrrolidone, partially saponified copolymer list from an acrylic ester and Acrylonitrile, polyvinyl alcohols with different residual acetate content, cellulose ether, gelatin, block copolymers, modified starch, low molecular weight, carbon and / or sulfonic acid group-containing polymers or mixtures of these substances are used.

Particularly preferred protective colloids are polyvinyl alcohols with a residual acetate content of less than 35, in particular 5 to 39 mol% and / or vinylpyrrolidone-oleyl propionate copolymers with a vinyl ester content of less than 35, in particular 5 to 30% by weight.

Nonionic or ionic emulsifiers, optionally also as a mixture, can be used. Preferred emulsifiers are, where appropriate, ethoxylated or propoxylated longer-chain alkanols or alkylphenols with different degrees of ethoxylation or propoxylation (e.g. adducts with 0 to 50 mol of alkylene oxide) or their neutralized, sulfated, sulfonated or phosphated derivatives. Neutralized dialkylsulfosuccinates or alkyldiphenyloxide disulfonates are also particularly suitable.

Combinations of these emulsifiers with the protective colloids mentioned above are particularly advantageous since they give particularly finely divided dispersions.

Special processes for the production of monodisperse polymer particles are also described in the literature (e.g. R.C. Backus, R.C. Williams, J. Appl, Physics 19,

S. 1186, (1948) have already been described and can be used with particular advantage for the production of the cores. It is only necessary to ensure that the particle sizes given above are observed. A further goal is to achieve the highest possible uniformity of the polymers. In particular, the particle size can be adjusted by selecting suitable emulsifiers and / or protective colloids or corresponding amounts of these compounds. By setting the reaction conditions such as temperature, pressure, reaction time, use of suitable catalyst systems which influence the degree of polymerization in a known manner and the selection of the monomers used for their preparation by type and proportion, the desired combinations of properties of the required polymers can be set in a targeted manner.

Monomers which lead to polymers with a high refractive index are generally those which either have aromatic partial structures or those which have heteroatoms with a high atomic number, such as, for example, B. halogen atoms, especially bromine or iodine atoms, sulfur or metal ions, d. H. via atoms or groupings of atoms which increase the polarizability of the polymers.

Polymers with a low refractive index are accordingly obtained from monomers or monomer mixtures which do not contain the mentioned partial structures and / or atoms with a high atomic number or only in a small proportion.

An overview of the refractive indices of various common homopolymers can be found e.g. B. in Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, Volume A21, page 169. Examples of radical-polymerizable monomers that lead to polymers with a high refractive index are:

Group a): styrene, alkyl-substituted styrenes in the phenyl core, α-methylstyrene, mono- and dichlorostyrene, vinyinaphthalene, isopropenylnaphthalene, isopropenylbiphenyl, vinylpyridine, isopropenylpyridine, vinyl carbazole, vinylanthracene, N-benzyi-methacrylamide, p-methacrylamide, p-methacrylamide. Group b): Acrylates which have aromatic side chains, such as. B. phenyl (meth) acrylate (= abbreviation for the two compounds phenyl acrylate and phenyl methacrylate), phenyl vinyl ether, benzyl (meth) acrylate, benzyl vinyl ether, and compounds of the formulas

In the formulas above and in the form below, to improve clarity and simplify the spelling, carbon chains are only represented by the bonds between the carbon atoms. This notation corresponds to the representation of aromatic cyclic compounds, z. B. the benzene is represented by a hexagon with alternating simple and double bonds.

Also suitable are those compounds which contain sulfur bridges instead of oxygen bridges, such as, for. B.

In the above form, R represents hydrogen or methyl. The phenyl rings of these monomers can carry further substituents. Such substituents are suitable for modifying the properties of the polymers produced from these monomers within certain limits. They can therefore be used in a targeted manner, in particular to optimize the properties of the effect colorants according to the invention which are relevant in terms of application technology.

Suitable substituents are in particular halogen, NO ₂ , alkyl having one to twenty carbon atoms, preferably methyl, alkoxy having one to twenty carbon atoms, carboxyalkyl having one to twenty carbon atoms, carbonylalkyl having one to twenty carbon atoms, or - OCOO alkyl with one to twenty

C-atoms. The alkyl chains of these radicals can in turn be optionally substituted or by double-bonded heteroatoms or structural groups such as. B. -O-, -S-, -NH-, -COO-, -OCO- or -OCOO- in non-adjacent positions.

Group c): monomers which have heteroatoms, such as, for. B. vinyl chloride, acylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, acrylamide and methacrylamide or organometallic compound such as. B.

Group d): The refractive index of polymers can also be increased by polymerizing in monomers containing carboxylic acid groups and converting the "acidic" polymers thus obtained into the corresponding salts with metals of higher atomic weight, such as, for. B. preferably with K, Ca, Sr, Ba, Zn, Pb, Fe, Ni, Co, Cr, Cu, Mn, Sn or

CD. The abovementioned monomers, which make a high contribution to the refractive index of the polymers produced therefrom, can be homopolymerized or copolymerized with one another. They can also be copolymerized with a certain proportion of monomers that make a lower contribution to the refractive index. Such copolymerizable monomers with a lower refractive index contribution are, for example, acrylates, methacrylates or vinyl ethers or vinyl esters with purely aliphatic radicals.

In addition, all bifunctional or polyfunctional compounds which can be copolymerized with the abovementioned monomers or which can subsequently react with the polymers with crosslinking can also be used as crosslinking agents for the production of crosslinked polymer cores from free-radically produced polymers or for the subsequent crosslinking of the matrix from matel material ,

In the following, examples of suitable crosslinkers are presented, which are divided into groups for systematization:

Group 1: bisacrylates, bismethacrylates and bisvinyl ethers of aromatic or aliphatic di- or polydydroxy compounds, in particular of butanediol (butanediol-di (meth) acrylate, butanediol-bis-vinyl ether), hexanediol (hexanediol-di (meth) acrylate, hexanediol-bis-vinyl ether ), Pentaerythritol, hydroquinone, bis-hydroxyphenylmethane, bis-hydroxyphenyl ether, bis-hydroxymethyl-benzene,

Ethylene oxide spacers, propylene oxide spacers or propylene oxide spacers.

Other crosslinkers in this group are e.g. B. di- or polyvinyl compounds such as divinybenzene or methylene bisacrylamide, triallyl cyanurate,

Divinylethylene urea, trimethylolpropane tri (meth) acrylate, trimethylol propane tricinyl ether, pentaerythritol tetra (meth) acrylate, pentaerythritol tetra vinyl ethers, and crosslinkers with two or more different reactive ends, such as. B. (meth) allyl (meth) acrylates of the formulas

, wherein R is hydrogen or methyl.

Group 2: reactive crosslinking agents which have a crosslinking effect, but mostly have a postcrosslinking effect, e.g. B. with heating or drying, and which are copolymerized into the core or shell polymers as copolymers.

Examples include: N-methylol- (meth) acrylamide, acrylamidoglycolic acid and their ethers and / or esters with C 1 to C 6 alcohols, diacetone acrylamide (DAAM), glycidyl methacrylate (GMA),

Methacryloyloxypropyl trimethoxysilane (MEMO), vinyl trimethoxysilane, m-isopropenyl benzyl isocyanate (TMI).

Group 3: Carboxylic acid groups which have been incorporated into the polymer by copolymerization of unsaturated carboxylic acids are crosslinked like polyvalent metal ions. For this purpose, preferably unsaturated carboxylic acids are acrylic acid,

Methacrylic acid, maleic anhydride, itaconic acid and veneric acid are used. Mg, Ca, Sr, Ba, Zn, Pb, Fe, Ni, Co, Cr, Cu, Mn, Sn, Cd are suitable as metal ions. Ca, Mg and Zn, Ti and Zr are particularly preferred.

Group 4: Post-crosslinked additives. This is understood to mean additives which are functionalized to a greater or greater extent and which react irreversibly with the polymer (by addition or preferably condensation reactions) to form a network. Examples of this are compounds that are per Molecule have at least two of the following reactive groups: epoxy, aziridine, isocyanate acid chloride, carbodiimide or carbonyl groups, further z. B. 3,4-dihydroxy-imidazolinone and its derivatives (Fixapret brands from BASF).

As already explained above, postcrosslinkers with reactive groups such as e.g. B. epoxy and isocyanate groups complementary reactive groups in the polymer to be crosslinked. For example, isocyanates react with alcohols to form urethanes, with amines to form urea derivatives, while epoxides react with these complementary groups to form hydroxyethers or hydroxyamines.

Post-crosslinking is also understood to mean photochemical curing, an oxidative or an air or moisture-induced curing of the systems.

The monomers and crosslinking agents mentioned above can be combined with one another and (co-) polymerized in a targeted manner in such a way that an optionally crosslinked (co-) polymer is obtained with the desired refractive index and the required stability criteria and mechanical properties.

It is also possible to use other common monomers, e.g. As acrylates, methacrylates, vinyl esters, butadiene, ethylene or styrene, additionally copolymerize, for example to adjust the glass transition temperature or the mechanical properties of the core and / or shell polymers as required.

It is likewise preferred according to the invention if the coating of organic polymers is carried out by grafting, preferably by emulsion polymerization or ATR polymerization. there the methods and monomers described above can be used accordingly.

In particular, when using inorganic cores, it may also be preferred that the core is one before the shell is polymerized on

Is subjected to pretreatment, which enables the jacket to be tied. This can usually consist in a chemical functionalization of the particle surface, as is known from the literature for a wide variety of inorganic materials. It can be particularly preferred to have such chemical on the surface

Functions to be attached which, as an active chain end, enable a grafting of the jacket polymers. Here are examples as terminal double bonds, epoxy functions as well

To name polycondensable groups. The functionalization of hydroxyl-bearing surfaces with polymers is known for example from EP-A-337 144. Other methods of modifying particle surfaces are well known to those skilled in the art and are described, for example, in various textbooks such as Unger, K.K., Porous Silica, Elsevier Scientific Publishing Company (1979).

In a likewise preferred embodiment of the present invention, the effect colorants contain at least one contrast material. The contrast materials cause an increase in the brilliance, contrast and depth of the color effects observed in the effect colorants according to the invention. Contrast materials are understood according to the invention to mean all materials which bring about such an enhancement of the optical effect. These contrast materials are usually pigments.

In the context of the present invention, pigments mean any solid

Understood substance that shows an optical effect in the visible wavelength range of light. According to the invention, in particular substances referred to as pigments that correspond to the definition of pigments according to DIN 55943 or DIN 55945. According to this definition, a pigment is an inorganic or organic, colored or achromatic colorant that is practically insoluble in the application medium. Both inorganic and organic pigments can be used according to the invention.

According to their physical mode of operation, pigments can be divided into absorption pigments and gloss pigments. at

Absorption pigments are pigments that absorb at least part of the visible light and therefore produce a color impression and, in extreme cases, appear black. According to DIN 55943 or DIN 55944, luster pigments are pigments in which luster effects are created by specular reflection on predominantly flat and aligned metallic or highly refractive pigment particles. According to these standards, interference pigments are glossy pigments whose coloring effect is wholly or predominantly based on the phenomenon of interference. These are in particular so-called mother-of-pearl

Pigments or fire-colored metal bronzes. Of particular importance among the interference pigments are the pearlescent pigments, which consist of colorless, transparent and highly refractive platelets. After orientation in a matrix, they produced a soft gloss effect, which is referred to as pearlescent.

Examples of Peilglanz pigments are guanine-containing fish silver, pigments based on lead carbonates, bismuth oxychloride or titanium dioxide mica. In particular, the titanium dioxide mica, which is characterized by mechanical, chemical and thermal stability, is often used for decorative purposes. According to the invention, both absorption and gloss pigments can be used, and interference pigments in particular can also be used. It has been shown that the use of absorption pigments is preferred in particular to increase the intensity of the optical effects. Both white and

Coloring or black pigments are used, the term color pigments meaning all pigments which give a different color impression than white or black, such as, for example, Heliogen ™ Blue K 6850 (from BASF, Cu-phthalocyanine pigment), Heliogen ™ Green K 8730 ( BASF, Cu phthalocyanine pigment), Bayferrox ™ 105 M (Bayer, iron oxide-based red pigment) or chrome oxide green GN-M (Bayer, chrome oxide-based green pigment). Again, the black pigments are preferred among the absorption pigments because of the color effects achieved. For example, pigmentary carbon black (e.g. the carbon black product line from Degussa (in particular

Purex ™ LS 35 or Corax ™ N 115)) as well as iron oxide black, manganese black, cobalt black and antimony black. Black mica qualities can also be used advantageously as black pigment (eg Iriodin ™ 600, Merck; iron oxide-coated mica).

It has been shown that it is advantageous according to the invention if the particle size of the at least one contrast material is at least twice as large as the particle size of the core material. If the particles of the contrast material are smaller, only insufficient optical effects are achieved. It is believed that smaller particles interfere with the arrangement of the nuclei in the matrix and cause a change in the lattices that form. The particles of at least twice the size of the cores which are preferably used according to the invention interact only locally with the lattice formed from the core. electron microscope

Recordings prove that the embedded particles from the grid Do not or only slightly disturb core particles. The particle size of the contrast materials, which are often also platelet-shaped as pigments, means the greatest extent of the particles in each case. If platelet-shaped pigments have a thickness in the region of the particle size of the cores and or even below it, this disturbs the

According to the available investigations, lattice orders are not. It has also been shown that the shape of the embedded contrast material particles has little or no influence on the optical effect. According to the invention, both spherical and platelet-shaped and needle-shaped contrast materials can be incorporated. Only the absolute particle size in relation to the particle size of the nuclei seems to be of importance. It is therefore preferred according to the invention if the particle size of the at least one contrast material is at least twice as large as the particle size of the core material, the particle size of the at least one contrast material preferably being at least four times as large as the particle size of the core material, since then the observable interactions are even smaller are.

A reasonable upper limit for the particle size of the contrast materials results from the limit at which the individual particles themselves become visible or, owing to their particle size, impair the mechanical properties of the effect colorant. The person skilled in the art has no difficulty in determining this upper limit.

The amount of contrast material that is used is also important for the effect desired according to the invention. It has been shown that effects are usually observed when at least 0.05% by weight of contrast material, based on the weight of the effect colorant, is used. It is particularly preferred if the effect colorant is at least 0.2% by weight and particularly preferably at least 1% by weight. % Contains contrast material, since these increased contents of contrast material generally also lead to more intensive effects according to the invention.

Conversely, larger amounts of contrast material may impair the processing properties of the core / shell particles and thus make it more difficult to produce the effect colorants according to the invention. In addition, it is expected that above a certain proportion of contrast material, which depends on the respective material, the formation of the lattice from core particles will be disturbed and that rather oriented contrast material layers will form. It is therefore preferred according to the invention if the effect colorant contains a maximum of 20% by weight of contrast material, based on the weight of the effect colorant, it being particularly preferred if the effect colorant contains a maximum of 12% by weight and particularly preferably a maximum of 5% by weight. Contains contrast material.

In a particular embodiment of the present invention, however, it can also be preferred if the effect colorants contain as large amounts of contrast material as possible. This is particularly the case if the contrast material is to increase the mechanical strength of the effect colorant at the same time.

The effect colorant according to the invention is preferably platelet-shaped particles whose thickness is preferably in the range from 0.5 to 20 μm, particularly preferably in the range from 1 to 10 μm, with at least 5, preferably at least 8 and in particular in the platelet in each spatial direction preferably at least 10 core layers follow one another.

The effect colorants according to the invention can be obtained by grinding or breaking from films of core-shell particles, the production of which in

Principle described in DE-A-10145450 can be obtained. Accordingly, the present invention further provides a process for the production of effect colorants, in which core-shell particles, the core of which is essentially solid and have an essentially monodisperse size distribution, with a difference between the refractive indices of the core material and the shell material , a film is produced, the matrix of which is brittle, and the film is subsequently comminuted into particles, preferably ground.

In a preferred process, core-shell particles are used, the shell of which is made of polymers

Have glass transition temperature T _G above 25 ° C, preferably above 50 ° C and particularly preferably above 70 ° C.

Corresponding polymers are well known to the person skilled in the art and can be found, for example, in Brandrup, J. (Ed.) .: Polymer Handbook. Chichester Wiley 1966. Preferred jacket materials are homo- or copolymeric poly (cyclohexyl methacrylate), polystyrene and substituted ones

Polystyrene derivatives, such as. B. poly (iodostyrene) and poly (bromostyrene),

Polyacrylates and polymethacrylates with a Tg above the

Service temperature, high Tg polyvinyl chloride and other vinyl polymers resulting from conversion from polyvinyl acetate,

Polyacrylonitrile and styrene-acrylonitrile copolymers or mixtures of the homo- or copolymers mentioned.

In another preferred method, core-shell particles are used, the shell of which consists of polymers that are crosslinkable

Have functionality. In this process variant, the core-shell particles are preferably additized with postcrosslinking additives before the film is produced and the actual crosslinking takes place after the film has been produced. The post-crosslinker or crosslinkable functionality can in particular be those described above

Compounds or monomers are used. Networking can are started according to the methods described, thermal activation for postcrosslinking being particularly preferred.

During the production of the films, a mixture of core-shell particles and possibly other additives is first produced. The mixture is then preferably subjected to a mechanical force at a temperature at which the jacket is flowable.

In a preferred variant of the production of films according to the invention, the temperature at which the mixture is exposed to the mechanical force is at least 40 ° C., preferably at least 60 ° C. above the glass point of the shell of the core-shell particles. It has been shown empirically that the flowability of the jacket in this temperature range particularly meets the requirements for economical production of the films.

In a likewise preferred process variant which leads to films according to the invention, the flowable mixtures are cooled under the action of the mechanical force to a temperature at which the jacket is no longer flowable.

The mechanical action of force can, according to the invention, be such a force action that occurs in the usual processing steps of polymers. In preferred variants of the present invention, the mechanical force is applied either: - by uniaxial pressing or - during a transfer pressing process, - during a (co-) extrusion or - during a calendering process or - during a blowing process. If the force is exerted by uniaxial pressing, the films according to the invention are preferably films. Films according to the invention can preferably also be produced by calendering, film blowing or flat film extrusion. The different ways of processing polymers under

The action of mechanical forces is well known to the person skilled in the art and can be found, for example, in the standard textbook Adolf Franck, "Plastic Compendium"; Vogel-Verlag; 1996 are taken.

If it is technically advantageous, the films according to the invention can contain auxiliaries and additives. They can be used to optimally set the application data or properties desired or required for application and processing. Examples of such auxiliaries and / or additives are plasticizers, film-forming aids, leveling agents, fillers, melting aids,

Adhesives, release agents, application aids, agents for viscosity modification, e.g. B. thickener.

Additions of film-forming aids and film-modifying agents based on compounds of the general are particularly recommended

Formula HO-C _n H ₂ n-0- (C _n H ₂ n-0) mH, where n is a number from 2 to 4, preferably 2 or 3, and m is a number from 0 to 500. The number n can vary within the chain and the various chain links can be built in in a statistical or block-wise distribution. Examples of such auxiliaries are ethylene glycol, propylene glycol, di-, tri- and

Tetraethylene glycol, di-, tri- and tetrapropylene glycol, polyethylene oxides, polypropylene oxide and ethylene oxide / propylene oxide mixed polymers with molecular weights up to approx. 15000 and statistical or block-like distribution of the ethylene oxide and propylene oxide assemblies.

If appropriate, organic or inorganic solvents, dispersants or diluents which, for example, extend the open time of the formulation, ie the time available for its application to substrates, are also possible, waxes or hot-melt adhesives as additives. If desired, stabilizers against UV radiation and weather influences can also be added to the films. For this purpose, z. B. derivatives of 2,4-dihydroxybenzophenone, derivatives of 2-cyano-3,3'-dephenyl acrylate, derivatives of 2,2 ', 4,4'-tetrahydroxybenzophenone,

Derivatives of o-hydroxyphenyl-benzotriazole, salicylic acid esters, o-hydroxyphenyl-s-triazines or sterically hindered amines. These substances can also be used individually or as mixtures.

The total amount of auxiliaries and / or additives is up to 40% by weight.

%, preferably up to 20% by weight, particularly preferably up to 5% by weight, of the weight of the films. Accordingly, the films consist of at least 60% by weight, preferably at least 80% by weight and particularly preferably at least 95% by weight of core-shell particles.

The effect colorants according to the invention are produced from these films by cutting, breaking and / or grinding the films to give pigments of a suitable size. This process can take place, for example, in a continuous belt process. A rolling mill or a grinder can be used. If particularly uniform particle sizes are desired for the effect colorants, one or more sieving steps can follow the comminution step.

The resulting pigments are particularly suitable for use in paints, varnishes, printing inks, plastics, ceramic materials, glasses and cosmetic formulations. For this you can also use commercially available pigments, for example inorganic and organic absorption pigments, metallic effect pigments and LCP

Pigments, mixed. Furthermore, the particles according to the invention are also suitable for the production of pigment preparations and for the production of dry preparations, such as, for example, granules. Such pigment particles preferably have a platelet-shaped structure with an average particle size of 5 μm - 5 mm.

The pigment of the invention can then be used to pigment paints, powder coatings, paints, printing inks, plastics and cosmetic formulations, such as e.g. lipsticks, nail polishes, cosmetic sticks, press powder, make-ups, shampoos and loose powders and gels.

The concentration of the effect colorant in the application system to be pigmented, i.e. the dispersion is generally between 0.1 and 70% by weight, preferably between 0.1 and 50% by weight and in particular between 1.0 and 20% by weight, based on the total solids content of the system. It is usually dependent on the specific

Application. Plastics usually contain the pigment according to the invention in amounts of from 0.01 to 50% by weight, preferably from 0.01 to 25% by weight, in particular from 0.1 to 7% by weight, based on the plastic composition. In the paint sector, the pigment mixture is used in amounts of 0.1 to 30% by weight, preferably 1 to 10% by weight, based on the

Lacquer dispersion used. Among the coating dispersions, alkyd resins have proven to be particularly advantageous for incorporating the effect colorants according to the invention. Alkyd resins are physically curing paints made from polyester resins, oils and fatty acids with a solvent content of usually less than 15%. In the

Pigmentation of binder systems, e.g. for paints and printing inks for gravure printing, offset printing or screen printing, or as a preliminary product for printing inks, e.g. in the form of highly pigmented pastes, granules, pellets, etc., have become especially pigment mixtures with spherical colorants, such as Ti0 ₂ , carbon black , Chromium oxide, iron oxide and organic

“Color pigments” have proven to be particularly suitable. The pigment is generally added to the printing ink in amounts of 2-35% by weight, preferably 5- 25 wt .-%, and in particular 8-20 wt .-% incorporated. Offset printing inks can contain the pigment up to 40% by weight or more. The preliminary products for the printing inks, for example in granular form, as pellets, briquettes, etc., contain up to 95% by weight of the pigment according to the invention in addition to the binder and additives. Subject of

The invention therefore also includes dispersions which contain the effect colorant according to the invention and contain a suitable film former and / or carrier.

The following examples are intended to explain the invention in more detail without limiting it.

Examples

Abbreviations used: ALMA allyl methacrylate AN acrylonitrile APS ammonium peroxodisulfate BDDA butane-1,4-diol diacrylate CHMA cyclohexyl methacrylate MMA methyl methacrylate SDS dodecyl sulfate sodium salt SDTH sodium dithionite PCHMA poly (cyclohexyl methacrylate) PS poly (styrene)

Example 1: Production of particles with a core made of polystyrene. Intermediate layer made of p (MMA-co-ALMA) and sheath made of polv (cvclohexyl methacrylate)

In a 1 liter stirred tank reactor preheated to 75 ° C. with a propeller stirrer, argon protective gas inlet and reflux condenser, a template heated to 4 ° C., consisting of 217 g water, 3.6 g styrene (from MERCK, destabilized) and 130 mg SDS (MERCK) filled and dispersed with vigorous stirring. Immediately after filling, the reaction is started by directly adding 50 mg SDTH (MERCK), 350 mg APS (MERCK) and again 50 mg SDTH, each dissolved in 5 g water. After 20 minutes, a monomer emulsion of 8.1 g BDDA (from MERCK, destabilized), 72.9 g styrene (from MERCK, destabilized), 0.375 g SDS, 0.1 g KOH and 110 g water over a period of 120 minutes continuously metered. The reactor contents are stirred for 30 minutes without further addition. Then 200 mg is added APS, dissolved in 5 g water. After stirring for a further 60 min, a second monomer emulsion consisting of 1.5 g ALMA (MERCK, destabilized), 13.5 g MMA (MERCK, destabilized), 0.075 g SDS and 20 g water is continuous over a period of 25 min added. The reactor contents are then stirred for 30 minutes without further addition. Then there is a

Add 200 mg APS, dissolved in 5 g water. A monomer emulsion composed of 120 g of CHMA (Degussa, destabilized), 120 g of water and 0.4 g of SDS is then metered in continuously over a period of 150 min. For almost complete reaction of the monomers, the mixture is then stirred for another 60 min. The core-shell particles are then precipitated in 1 l of methanol, the precipitation is completed by adding 25 g of concentrated aqueous sodium chloride solution, and the suspension is distilled with 1 l of distilled water. Water added, suction filtered and dried.

Example 2: Production of particles with a core made of polv (methyl methacrylate) and a jacket made of polystyrene

In a 1-liter stirred tank reactor preheated to 75 ° C. with a propeller stirrer, argon protective gas inlet and reflux condenser, a receiver is heated to 4 ° C., consisting of 217 g water, 0.4 g ALMA (Fa.

MERCK, destabilized), 3.6 g MMA (MERCK, destabilized) and 23 mg

SDS (MERCK) filled and dispersed with vigorous stirring. Immediately after filling, the reaction is started by directly adding 30 mg SDTH (MERCK), 150 mg APS (MERCK) and again 30 mg SDTH, each dissolved in 5 g water. After 20 minutes, a monomer emulsion of 9.6 g ALMA (Merck, destabilized), 96 g MMA (MERCK, destabilized), 0.35 g SDS, 0.1 g

KOH and 130 g of water were metered in continuously over a period of 120 min. The reactor contents are stirred for 60 minutes without further addition.

Then 100 mg of APS are added, dissolved in 5 g of water. After stirring for a further 10 min, a second monomer emulsion of 120 g Styrene (from MERCK, destabilized), 0.4 g of SDS and 120 g of water were metered in continuously over a period of 150 min. For almost complete reaction of the monomers, the mixture is then stirred for a further 60 min. The core-shell particles are then precipitated in 1 l of methanol, the precipitation is completed by adding 25 g of concentrated aqueous sodium chloride solution, and the suspension is distilled with 1 l of distilled water. Water added, suction filtered and dried.

Example 3: Production of particles by isostatic pressing and subsequent grinding

5 g of the dried coagulate from Examples 1 and 2 are in a microextruder (Thermo Haake, Minilab 5, co-rotating) with 0.2 wt .-% Licolub Fa1 and 0.2 wt .-% Licolub WE 40 (both from Clariant) compounded at a temperature of 190 ° C and a screw speed of 200 rpm for 30 min. The extrudate from the perforated nozzle is rolled up to a screw and pressed with a laboratory press (from Collin) between two PET films according to the following program into thin films:

The thin films are then ground into small particles in an agate mortar. Example 4: Preparation of a paint dispersion

Formulations each consisting of 5% by weight of effect colorant from Example 3 in alkyd resin clearcoat (Swing Color Clearcoat glossy from Bauhaus) are prepared by stirring the pigment particles into the paint.

The resulting dispersion is spread on a paint card. After the paint formulation has dried and hardened, a color effect coating results from brightly reflecting pigments which, depending on the viewing direction, have an intensely green or intensely blue color.

Example 5: Production of particles by extrusion of films and subsequent grinding

3 kg of the core-shell particles from example 1 or 2 are comminuted in a cutting mill (Rapid, type: 1528) with ice cooling and then in a single-screw extruder (Plasti-Corder; Brabender; screw diameter 19 mm with 1- Hole nozzle (3mm)) compounded. After a cooling section, a granulator A 90-5 (Fa.

Automatic) granulated. The granules are made on a flat film line consisting of a single-screw extruder (from Göttfert; type: extrusiometer; screw diameter 20 mm; L / D 25), a thickness-adjustable film tool (width 135 mm) and a temperature-controlled smoothing unit (from Leistritz; roll diameter 15 mm;

Roller width 350 mm) processed. A film strip 125 mm wide and 1 mm thick is obtained. The film is crushed into pigment particles in a rolling mill.

Example 6: Production of core-shell particles with a crosslinkable shell In a stirred tank reactor preheated to 75 ° C. with a propeller stirrer, argon protective gas inlet and a reflux condenser, a template tempered to 4 ° C., consisting of 217 g water, 0.4 g butanediol diacrylate (Merck, destabilized), 3.6 g styrene ( BASF, destabilized) and 80 mg of sodium dodecyl sulfate (SDS; Merck) and under strong

Dispersed stirring. Immediately after filling, the reaction is started by successively adding 50 mg of sodium dithionite (Merck), 250 mg ammonium peroxodisulfate (Merck) and again 50 mg of sodium dithionite (Merck), each dissolved in 5 g of water. After 10 minutes, a monomer emulsion of 6.6 g of butanediol diacrylate (from

Merck, destabilized), 59.4 g of styrene (from BASF, destabilized), 0.3 g of SDS, 0.1 g of KOH and 90 g of water were metered in continuously over a period of 210 min. The reactor contents are stirred for 30 minutes without further addition. A second monomer emulsion is then made from 3 g of allyl methacrylate (Merck, destabilized), 27 g of methyl methacrylate

(BASF, destabilized), 0.15 g of SDS (Merck) and 40 g of water were metered in continuously over a period of 90 minutes. The reactor contents are then stirred for 30 minutes without further addition. A monomer emulsion of 130 g of ethyl acrylate (from BASF, destabilized), 139 g of water, 4 g of hydroxyethyl methacrylate and 0.33 g of SDS (from Merck) is then metered in continuously over a period of 180 min. For almost complete reaction of the monomers, the mixture is then stirred for another 60 min. The core-shell particles are then precipitated in 1 liter of methanol, with 1 liter of dist. Water added, suction filtered and dried.

Example 6a: Core-shell particles, the shell of which consists of 80% by weight Cvclohexyl methacrylate, 18% by weight ethyl acrylate and 2% by weight hydroxyethyl methacrylate

In a 1 liter stirred tank reactor preheated to 75 ° C with propeller stirrer, argon protective gas inlet and reflux cooler, one is heated to 4 ° C temperature-controlled template, consisting of 217 g of water, 3.6 g of styrene (from Merck, destabilized), 0.4 g of BDDA (1, 4-butanediol diacrylate, from Merck) and 100 mg of SDS (sodium dedecyl sulfate, from Merck) filled and dispersed with vigorous stirring. Immediately after filling, the reaction is started by directly adding 50 mg sodium bisulfite (Merck), 350 mg sodium peroxodisulfate (Merck) and again 50 mg sodium bisulfite, each dissolved in 5 g water. After 20 minutes, a monomer emulsion of 8.1 g BDDA, 72.9 g styrene (Merck, destabilized), 0.375 g SDS, 0.1 g KOH and 110 g water is metered in continuously over a period of 120 minutes. The reactor contents are stirred for 30 minutes without further addition. A second monomer emulsion comprising 1.5 g of ALMA (from Merck, destabilized), 13.5 g of MMA (methyl methacrylate, from Merck, desatbilized), 0.075 g of SDS and 20 g of water is then metered in continuously over a period of 25 minutes , The reactor contents are then stirred for 30 minutes without further addition. A monomer emulsion consisting of 100 g CHMA (cyclohexyl methacrylate) (Degussa, destabilized), 20 g ethyl acrylate (Merck, destabilized), 5 g hydroxyethyl methacrylate (Merck, destabilized), 136 g water and 0.375 g SDS ( Na dodecyl sulfate) was metered in continuously over a period of 150 min. For almost complete reaction of the monomers, the mixture is then stirred for a further 60 min. The core-shell particles are then precipitated in 1 liter of methanol, the precipitation is completed by adding 25 g of concentrated aqueous sodium chloride solution, the suspension is mixed with 1 liter of demineralized water, suction filtered and dried.

5 g of the dried coagulate are in a microextruder (Thermo Haake, Minilab 5, co-rotating) with 0.2% by weight Licolub FA1 (Clariant) and 2% by weight of a resin formulation 9-FEST / IC-HPP10447 (Bayer Materialscience AG) at a temperature of 150 ° C and a

Screw speed of 200 rpm compounded over 10 min. The extrudate from the perforated nozzle is rolled up to a screw and with a Laboratory press (Collin) pressed into thin films between two PET films according to the following program:

Level 1 Level 2 Press time [min] 1 2 Pressure [bar] 1 200 Temperature [° C] 195 195

The film is removed hot from the press and then cooled without pressure. The film is then heated at 220 ° C. for 10 min without pressure for crosslinking. The thin film is then ground into small particles in an agate mortar.

Example 7: Production of particles by extrusion of films and subsequent grinding

3 kg of the core-shell particles from Example 6 or 6a are comminuted in a cutting mill (Rapid, type: 1528) with ice cooling and then in a single-screw extruder (Plasti-Corder; Fa.

Brabender; Screw diameter 19 mm with 1 hole nozzle (3mm) with 2

% By weight isocyanate hardener (CRELAN ™; Bayer) compounded. After a cooling section, granulation is carried out in an A 90-5 granulator (from Automatic). The granules are placed on a flat film line consisting of a single-screw extruder (from Göttfert; type: extrusiometer;

Screw diameter 20 mm; L / D 25), an adjustable thickness

Foil tool (width 135 mm) and a temperable smoothing unit (Fa.

Leistritz; Roll diameter 15 mm; Roller width 350 mm) processed. A film strip 125 mm wide and 1 mm thick is obtained.

The film is then heated to 190 ° C. After crosslinking, the brittle film is crushed into pigment particles in a rolling mill.

Claims

claims

1. Effect colorant consisting essentially of core-shell particles, the shell of which forms a matrix and whose core is essentially solid and has an essentially monodisperse size distribution, there being a difference between the refractive indices of the core material and the shell material, characterized in that the matrix is brittle.

2. Effect colorant according to claim 1, characterized in that in the core-shell particles, the shell is firmly connected to the core via an intermediate layer.

3. Effect colorant according to at least one of the preceding claims, characterized in that the matrix is essentially formed by crosslinked organic polymers.

4. Effect colorant according to at least one of the preceding claims, characterized in that the glass transition temperature TG of the matrix is above 25 ° C, preferably above 50 ° C and particularly preferably above 70 ° C.

5. effect colorant according to the preceding claim, characterized in that it is a homo- or copolymeric poly (cyclohexyl methacrylate), polystyrene and substituted polystyrene derivatives, such as. B. poly (iodostyrene) and poly (bromostyrene), polyacrylates and polymethacrylates with a Tg above the service temperature, polyvinyl chloride with high Tg and other vinyl polymers which result from conversion from polyvinyl acetate, polyacrylonitrile and styrene-acrylonitrile Copolymers or mixtures of the homo- or copolymers mentioned.

6. Effect colorant according to at least one of the preceding claims, characterized in that the core consists of a material which either does not flow or becomes flowable at a temperature above the flow temperature of the jacket material, the material preferably being a crosslinked organic polymer or a inorganic material, preferably a metal or semimetal or a metal chalcogenide or metal pnictide.

7. effect colorant according to at least one of the preceding claims, characterized in that the effect colorant consists of at least 60 wt .-%, preferably at least 80 wt .-% and particularly preferably at least 95 wt .-% of core-shell particles.

8. Effect colorant according to at least one of the preceding claims, characterized in that the core-shell particles have an average particle diameter in the range from about 5 nm to about 2000 nm, preferably in the range from about 5 to 20 nm or in the range from 40-500 nm.

9. Effect colorant according to at least one of the preceding claims, characterized in that the difference between the refractive indices of the core material and the cladding material is at least 0.001, preferably at least 0.01 and particularly preferably at least 0.1.

10. Effect colorant according to at least one of the preceding claims, characterized in that it contains at least one contrast material, it being the at least one contrast material preferably a pigment, preferably an absorption pigment and particularly preferably a black pigment, the effect colorant containing at least 0.05% by weight of contrast material, based on the weight of the effect colorant, it being particularly preferred if the effect colorant is at least 0 Contains 2% by weight and particularly preferably at least 1% by weight of contrast material.

11. The effect colorant according to claim 10, characterized in that the effect colorant contains a maximum of 20% by weight of contrast material, based on the weight of the effect colorant, it being particularly preferred if the effect colorant is a maximum of 12% by weight and particularly preferably a maximum Contains 5% by weight of contrast material.

12. Effect colorant according to at least one of the preceding claims, characterized in that the effect colorant is platelet-shaped particles, the thickness of which is preferably in the range from 0.5 to 20 μm, particularly preferably in the range from 1 to 10 μm, in which Platelets in each spatial direction are followed by at least 5, preferably at least 8 and particularly preferably at least 10 core layers.

13. A method for producing effect colorants, characterized in that a film is produced from core-shell particles, the core of which is essentially solid and has an essentially monodisperse size distribution, with a difference between the refractive indices of the core material and the shell material , the matrix of which is brittle, and the film is then broken up into particles, preferably ground.

14. The method according to claim 13, characterized in that core-shell particles are used whose shell made of polymers have a glass transition temperature T _G of above 25 ° C, preferably above 50 ° C and particularly preferably above 70 ° C, wherein the jacket material is preferably a homo- or copolymeric poly (cyclohexyl methacrylate), polystyrene and substituted polystyrene derivatives, such as. B. poly (iodostyrene) and poly (bromostyrene), polyacrylates and polymethacrylates with a Tg above the temperature of use, high Tg polyvinyl chloride and other vinyl polymers resulting from conversion from polyvinyl acetate, polyacrylonitrile and styrene-acrylonitrile copolymers or mixtures of the mentioned homo- or copolymers.

15. The method according to claim 13, characterized in that core-shell particles are used, the shell of which consists of polymers which have a crosslinkable functionality, and the film becomes brittle by crosslinking the matrix.

16. Use of effect colorants according to at least one of claims 1 to 12 for pigmenting dispersions, such as lacquers, powder coatings, paints, printing inks, plastics and cosmetic formulations.

17. Dispersion containing at least one effect colorant according to at least one of claims 1 to 12 and at least one film former.