DE102010021530A1 - Use of surface-modified effect pigments in a solvent-free coating composition, solvent-free coating composition and coated article - Google Patents

Abstract

The present invention relates to the use of surface-modified effect pigments in a solvent-free coating composition, the surface-modified effect pigments having a platelet-shaped substrate and at least one dielectric layer, where at least one optional protective layer can be arranged on the at least one dielectric layer, and the effect pigments on the effect pigment surface with at least one surface-modified of an epoxy group-containing compound, with the proviso that the at least one epoxy group-containing compound contains no silicon atoms. Furthermore, the invention comprises a powder coating which contains these surface-modified effect pigments and an object which is coated with a powder coating which contains these surface-modified effect pigments.

Description

The present invention relates to the use of surface-modified effect pigments in a solvent-free coating composition, a solvent-free coating composition containing these surface-modified effect pigments, and a coated article. The surface-modified effect pigments can be used in a powder coating as well as in toners.

As solvent-free coating systems, powder coatings are an alternative to conventional wet-paint systems in many application areas with regard to increasingly stringent environmental regulations, such as VOC guidelines. Powder coatings are used, for example, in the painting of vehicle parts, garden furniture, camping articles, household appliances, refrigerators or shelves. Largely metallic objects are painted, but is also possible a painting of z. As plastics or glass.

The powder coating technology is based on the principle of electrostatic charging, wherein the electrostatic charging of the powder coating is usually carried out by the corona process or the triboelectric method.

In the corona process, the powder coating is charged via at least one electrode integrated in the powder coating gun. The powder coating passes on the one hand by the conveying air of the powder coating gun and on the other hand by the air movement in the application cabin, caused by the suction on the substrate to be coated. The deposition is supported by an applied electric field, which also leads to a partial coating of the substrate back. This is called wrap-around. In the triboelectric method, the charge transfer takes place by friction of the powder coating on a teflon tube arranged inside the powder coating gun. Powder coatings applied by this method usually have a positive charge. A combination of the two described methods in the coating process is possible.

Subsequently, the applied powder coating is melted by supplying thermal energy and subsequently cured. Excess powder coating, which does not adhere to the substrate to be coated, can be recovered and reused. Since this so-called overspray is generally finer than the powder coating originally used, the overspray is blended with powder coating not yet used in order to ensure a stable coating process and a high-quality powder coating.

While the corona process allows a largely universal use of powder coatings, specially adjusted powder coatings are required for the triboelectric process. Powder coatings, which are applied by the triboelectric method, generally show a better course on the substrate to be coated than after the corona-applied powder coatings. Without applied external voltage, only a weak electric field builds up, which allows the coating of Faraday cages. Substrates to be coated with a pronounced cavity are therefore preferably coated by the triboelectric method. The triboelectric method has the advantage over the corona method that the expense of generating and isolating the high voltage to operate the corona is eliminated. Compared to the corona process, however, the powder coating throughput is lower in the triboelectric process, so that less powder coating per unit time can be applied.

Powder coatings can be pigmented to obtain different colors and / or optical effects with organic or inorganic colorants and / or platelet-like effect pigments, such as metallic effect pigments or pearlescent pigments. If powder coating resins are provided, for example, with organic or inorganic pigments, they are extruded together with other powder coating constituents, such as hardeners, additives or fillers, after mixing and ground to ready-to-use powder coating after further process steps. Flaky effect pigments, such as metallic effect pigments or pearlescent pigments, are normally not incorporated into a powder coating in this manner. They are destroyed by the applied shear forces and thus do not give a visually appealing powder coating.

Alternative methods are available for incorporating platelet-shaped effect pigments into a powder coating. On the one hand, the so-called dry blend process, in which the platelet-shaped effect pigments and the powder coating are mixed. Due to the different shape and chargeability of the platelet-shaped effect pigments and the powder coating, segregation may occur during application, which makes the reuse of the oversprays difficult or impossible. If the overspray were to be applied again, the resulting powder coating would have altered optical properties. At the Corona Process is to be mentioned as a further disadvantage of powder coatings, which are prepared by the dry blend process, the adhesion of effect pigments to electrode and baffle plate of the powder paint gun. Such agglomerates are entrained from a certain size of the conveying air and lead to impact on the substrate to be coated to Lackierfehlern, so an undesirable visual appearance. If the agglomerates get into the overspray, there is an accumulation of the effect pigments, which has an adverse effect on the reuse.

Alternatively, platelet-shaped effect pigments can be incorporated into powder coatings by the so-called bonding method. In this case, the powder coating is heated in the presence of platelet-shaped effect pigments to the softening temperature and thereby melted on the surface, resulting in a more or less complete physical adhesion of the platelet-shaped effect pigments to the individual powder coating particles. Thus, the segregation occurring during the dry blend process can be avoided.

By means of powder coating technology, it is possible to apply coating layers with higher layer thicknesses than conventional coating methods, which may be advantageous in terms of chemical and physical resistance. In addition to the cost-effectiveness of the coating, the layer thickness also influences, for example, the accuracy of fit in the assembly of powder-coated elements.

Surface-applied pearlescent pigments which are provided with phosphorus-containing compounds are described in US Pat EP 1 812 518 B1 described. In powder paints pigmented with such pearlescent pigments, the pearlescent pigments show a leafing effect after application. In contrast to powder paints pigmented with untreated pearlescent pigments, a comparable visual impression of brilliance can be achieved with a smaller amount of the surface-occupied pigment.

In the EP 1 339 806 B1 For example, a powder coating composition comprising a resin carrier and a pigment will be described. The pigment is first coated with aluminum oxide or a mixture of cerium and aluminum oxides and a silane coupling agent. The latter can either be applied to the first layer or be present as a mixed layer with this.

From the EP 1 646 693 B1 For example, pearlescent pigments suitable for use in powder coatings ("powder coating precursors") are known. These are according to the, in the EP 1 339 806 B1 described pearlescent pigments, in which case additionally on the surface of the silane coupling agent z. For example, alumina, which is usually added as a flow or Rieselhilfe powder coatings, is present. The silane coupling agent is present as a separate layer.

The WO 2006/136435 A2 relates to a process for the preparation of pearlescent pigments which are coated with an oligomeric and / or polymeric binder which is uncured, chemically crosslinkable and / or crosslinkable under the action of heat, IR radiation, UV radiation and / or electron beams. Such pearlescent pigments are characterized by a high flexibility in the application. In powder coatings, it is particularly advantageous if the coating of the pigment is identical to the binder of the powder coating, so that it comes after application and curing of the powder coating to form a homogeneous coating layer in which the pearlescent pigments are chemically incorporated. In addition to an attractive appearance, such paint coatings are very resistant to, for example, mechanical stresses.

The WO 2005/063897 A2 relates to the method according to the teaching of WO 2006/136435 A2 manufactured metallic effect pigments.

Pigments surface-treated with a polyglycidyl ether, polyglycidyl ester or diglycidyl polysiloxane compound are known in the art EP 0 764 191 B1 known. This surface treatment is intended to prevent the settling and agglomeration of the pigments in liquid-containing coating agents, such as in a paint or an ink.

Polymer-coated pearlescent and metallic pigments are from EP 2 098 574 A2 known. The polymer layer is in this case covalently bonded to the at least one metal oxide layer of the pigment.

The WO 98/46682 A1 describes powder coating compositions containing metal or pearlescent pigments. In order to ensure a more uniform chargeability of the pigments and of the powder coating, the pigments are treated with a viscous liquid so that the pigments have a sticky surface. After mixing with the powder coating, the powder coating adheres to the sticky surface of the pigments.

US Pat. No. 7,618,489 B2 describes organic or inorganic color pigments coated with an epoxide compound which are used as color filters in flat panel displays.

The object of the present invention is to provide effect pigments for use in a solvent-free coating composition, in particular a powder coating or a toner, which produces a coating, in particular powder coating or printed image, which has a low optical depth effect.

In the case of the powder coating application of the effect pigments, there should also be no or negligible segregation phenomena at or the electrodes of the powder paint gun.

When used in a solvent-free coating composition, the effect pigments are intended to enable the provision of a coated article with a visually pleasing appearance without defects in the coating. They should be used for powder coatings in indoor and / or outdoor use. Powder-coated building facades should be characterized by their good cleaning ability and weathering stability. When used as a toner should give a uniform print image.

The object underlying the invention is achieved by the use of surface-modified effect pigments in a solvent-free coating composition, wherein the surface-modified effect pigments have a platelet-shaped substrate and at least one dielectric layer, wherein at least one optional protective layer can be arranged on the at least one dielectric layer, and the effect pigments the effect pigment surface are surface-modified with at least one epoxide group-containing compound, with the proviso that the at least one epoxide group-containing compound contains no silicon atoms.

Preferred developments are specified in the dependent claims 2 to 11.

The object on which the invention is based is also achieved by providing surface-modified effect pigments comprising platelet-shaped substrates with at least one dielectric layer, wherein at least one optional protective layer can be arranged on the at least one dielectric layer, wherein the effect pigments on the effect pigment surface are surface-modified with at least one epoxide group-containing compound with the proviso that the at least one epoxide group-containing compound does not contain silicon atoms, and the surface-modified effect pigments have a specific epoxide equivalent weight within the range of 119,000 to 800 based on the total weight of the surface-modified effect pigments.

The object of the invention is also achieved by providing a solvent-free coating composition containing surface-modified effect pigments, wherein the surface-modified effect pigments have a platelet-shaped substrate and at least one dielectric layer, wherein at least one optional protective layer can be arranged on the at least one dielectric layer, and the effect pigments on the Effect pigment surface are surface-modified with at least one epoxide group-containing compound, with the proviso that the at least one epoxide group-containing compound contains no silicon atoms.

Preferred developments of the solvent-free coating composition according to the invention are specified in claims 14 and 15.

Finally, the object underlying the invention is also achieved by providing a coated article, wherein the article is coated with a solvent-free coating composition according to the invention.

These coated with a powder paint objects are preferably facade elements, vehicle parts, bodies, household appliances, camping equipment, etc.

According to the invention, the at least one epoxide group-containing compound has no silicon atoms. Thus, the epoxide group-containing compounds to be used according to the invention do not comprise silanes containing epoxide groups and / or siloxanes or polysiloxanes containing epoxide groups. Hereinafter, for the sake of simplicity, only epoxide group-containing compounds are referred to, which means, however, exclusively epoxide group-containing compounds which do not contain any silicon atom (s).

The inventors have surprisingly found that the effect pigments to be used according to the invention not only have performance advantages which lead to coatings of high quality, ie in particular without undesired pigment agglomerates, but also that the visual appearance of the coating is significantly influenced by the modification of the effect pigment surface according to the invention. Powder coatings comprising the surface-modified effect pigments to be used according to the invention have, in contrast to, for example, powder coatings containing effect pigments prepared according to US Pat WO 2006/136435 A2 or WO 2005/063897 A2 a very homogeneous visual appearance. Powder coatings containing effect pigments according to WO 2006/136435 A2 or WO 2005/063897 A2 are characterized by their optical depth and their livelier appearance.

When the effect pigments according to the invention are used in a toner, an optically finer printed image is obtained.

According to a preferred embodiment of the invention, the solvent-free coating agent is a powder coating or a toner.

The statements made below with regard to the effect pigments to be used according to the invention apply both to the effect pigments claimed according to the invention and to the coating composition according to the invention, in particular the powder coating of the invention and the toner according to the invention. Thus, the properties given in the dependent claims 2 to 11 for the effect pigments as well as the explanations below also apply correspondingly to the surface-modified effect pigments claimed in claim 12 and also to the surface-modified effect pigments which are contained in the solvent-free coating composition claimed in claims 13 to 15 ,

A toner is understood to be a dry toner whose solvent content is at most 3% by weight, preferably at most 1% by weight. According to a further preferred embodiment, the content of solvent in the dry toner is at most 0.5% by weight. According to another preferred embodiment, the dry toner contains no solvent. The percentages by weight are based on the total weight of the toner.

According to a very preferred variant, the solvent-free coating agent is a powder coating. The powder coating of the invention contains no solvent.

The invention relates in particular to powder coatings which are prepared by the dry blend process and which contain the surface-modified effect pigments to be used according to the invention.

Suitable platelet-shaped substrates of the surface-modified effect pigments to be coated are metallic or non-metallic platelet-shaped substrates. The metals of the metallic platelet-shaped substrates may be selected from the group consisting of aluminum, copper, zinc, iron, titanium, stainless steel, silver, their alloys, and mixtures thereof. Preferably, the metals of the metallic platelet-shaped substrates are selected from the group consisting of aluminum, copper, zinc, iron, stainless steel, their alloys and mixtures thereof. The metals of the metallic platelet-shaped substrates are particularly preferably selected from the group consisting of aluminum, copper, zinc, iron, their alloys and mixtures thereof. Most preferably, the metals of the metallic substrates are selected from the group consisting of aluminum, copper, zinc, their alloys and mixtures thereof. Aluminum platelets are particularly preferably used as metallic platelet-shaped substrates.

The non-metallic platelet-shaped substrates are preferably substantially transparent, preferably transparent, d. H. for visible light, they are at least partially permeable. By partially permeable is understood according to the invention that the transmission is at least 50%, more preferably at least 70%, even more preferably at least 90%, in each case based on the incident light.

The non-metallic platelet-shaped substrates may be selected from the group consisting of natural mica, synthetic mica, glass flakes, SiO ₂ platelets, Al ₂ O ₃ platelets, polymer platelets, platelet-shaped substrates comprising an inorganic-organic mixed layer. Furthermore, non-metallic platelet-shaped substrates may be glass flakes coated on both sides with semitransparent metal layers selected from the group consisting of silver, aluminum, chromium, nickel, gold, platinum, palladium, copper, zinc, titanium, their alloys, and mixtures thereof , used become. According to the invention, as effect pigments it is also possible to use those whose substrates are mixtures of the platelet-shaped substrates indicated above.

Preferably, the non-metallic platelet-shaped substrates are selected from the group consisting of natural mica, synthetic mica, glass flakes, SiO ₂ platelets, Al ₂ O ₃ platelets, and mixtures thereof. More preferably, the non-metallic platelet-shaped substrates are selected from the group consisting of natural mica, synthetic mica, glass flakes and mixtures thereof. Very particular preference is given to substrates of natural and synthetic mica and mixtures thereof. In particular, as the substrate, natural mica is preferable.

The glass flakes which can be used as a substrate can be, for example, a composition according to the teaching of EP 1 980 594 B1 exhibit.

The surface-modified effect pigments which can be used for the inventive use in solvent-free coating systems, in particular powder coatings, are prepared by providing the platelet-shaped substrates with at least one dielectric coating, optionally at least one protective layer, and subsequently with at least one epoxide group-containing compound containing no silicon atoms.

The at least one dielectric coating, the optionally present at least one protective layer and the surface modification with at least one epoxide group-containing compound can either independently completely envelop the platelet-shaped substrate or be present only partially on the platelet-shaped substrate. The surface-modified effect pigments are preferably distinguished by a uniform, homogeneous structure of each of these layers. Thus, each layer preferably envelops the platelet-shaped substrate or the correspondingly already precoated substrate substantially completely, preferably completely. In particular, preferably also the edge regions and not only the upper and lower surfaces of the platelet-shaped substrates or the corresponding already precoated substrates are covered.

The at least one dielectric layer of the surface-modified effect pigments is preferably arranged directly on the platelet-shaped substrate. If at least one protective layer is arranged on the at least one dielectric layer, then the protective layer is arranged between the at least one dielectric layer and the surface modification with the at least one epoxide group-containing compound.

Since the effect pigment surface is surface-modified with the at least one epoxide group-containing compound, the epoxide group-containing compound is disposed on the outside. The at least one epoxide group-containing compound is preferably present in a layer, preferably at least partially enveloping the effect pigment surface.

In a further embodiment of the invention, the effect pigment to be used according to the invention comprises only a single dielectric layer, which is applied directly to the platelet-shaped substrate. In this embodiment, the epoxide group-containing compound is applied directly to the dielectric layer and at least partially enveloping it.

In a further embodiment of the invention, the effect pigment to be used according to the invention comprises only a single dielectric layer, which is applied directly to the platelet-shaped substrate, and a single protective layer, which is applied directly to the dielectric layer. In this embodiment, the epoxide group-containing compound is applied directly to the protective layer and at least partially enveloping it.

In a further variant of the invention, the effect pigment to be used according to the invention has two, three, four, five, six or more dielectric layers. The dielectric layers are preferably applied directly following one another.

The at least one optional protective layer is preferably disposed externally with respect to the dielectric layers, such that the dielectric layers are disposed between the platelet-shaped substrate and the protective layer.

In a further preferred embodiment, the layer sequence of dielectric layers is arranged alternately with respect to the refractive index. Preferably, the alternately arranged high- and low-refractive dielectric layers are arranged directly on the substrate, the optional protective layer directly on said layer sequence and the epoxide group-containing compound directly on the optional protective layer or directly on said layer sequence. In another embodiment, the layer sequence of alternating high and low refractive dielectric layers preferably begins and ends with a high refractive index layer such that a high refractive index dielectric layer followed by a low refractive index dielectric layer followed by a high refractive index dielectric layer is disposed on the platelet shaped substrate.

Under a dielectric layer is a non- or weakly electrically conductive coating for the purposes of this invention, ie, a layer with a resistivity of 1 x 10 ⁴ ohm-m and larger understood. Reference may be made to literature values for known substances.

As the dielectric layer, layers comprising metal oxides, metal oxide hydrates, metal hydroxides, metal suboxides, metal fluorides, metal oxyhalides, metal chalcogenides, metal nitrides, metal oxynitrides, metal sulfides, metal carbides, organic dielectric materials and / or mixtures thereof are preferably applied. According to a preferred variant, the dielectric coating consists of the abovementioned materials.

In another embodiment, the dielectric layer may comprise or consist of only a single one of these compounds. Alternatively, the dielectric layer may also comprise several of the compounds listed above in the same layer. For example, the dielectric layer may comprise at least two different metal oxides or a metal oxide and a metal hydroxide of one or more metals. The dielectric layer may thus comprise at least two of the compounds listed above as a mixture in the same layer or as separate layers.

Metal oxides, metal oxide hydrates, metal hydroxides, organic dielectric materials and / or mixtures thereof are preferably used as the dielectric layer. Particular preference is given to using metal oxides and metal oxide hydrates and / or mixtures thereof.

For the purposes of this invention, organic dielectric materials are understood as meaning organic monomers and polymers. These include, inter alia, acrylates, polyethers, polyamides, (poly) urethanes, polyolefins, isocyanates, latex or cellulose derivatives. Preferably, acrylates and / or polyethers are used.

The terms layer or coating are used interchangeably within the meaning of this invention, unless stated otherwise.

The dielectric layer may comprise a high refractive index layer having a refractive index of n ≥ 1.8, preferably n ≥ 1.9 and more preferably n ≥ 2.0, or a low refractive index layer having a refractive index of n <1.8, preferably n <1.7, and more preferably n <1.6.

In a further embodiment, the dielectric layer may be an optically active layer.

Examples of suitable dielectric high-index layers are metal oxides such as titanium oxide, preferably titanium dioxide (TiO ₂ ), iron oxide, preferably iron (III) oxide (Fe ₂ O ₃ ), zinc oxide preferably ZnO, tin oxide, preferably tin dioxide (SnO ₂ ), zirconium oxide, preferably zirconium dioxide (ZrO ₂ ), antimony oxide preferably Sb ₂ O ₃ , magnesium oxide, preferably MgO, cerium oxide, preferably CeO ₂ , cobalt oxide, preferably CoO, chromium oxide, preferably chromium (III) oxide (Cr ₂ O ₃ ), copper oxide, preferably copper (I) oxide (Cu ₂ O) and / or copper (II) oxide (CuO), metal sulfides such as zinc sulfide, preferably ZnS, metal oxide hydrates such as goethite (FeOOH), titanates such as calcium titanate (CaTiO ₃ ) or iron titanates such. B. Ilmenite (FeTiO ₃ ), pseudobrookite (Fe ₂ TiO ₅ ) and / or pseudorutile (Fe ₂ Ti ₃ O ₉ ), doped metal oxides, such as with Fe ₂ O ₃ doped TiO ₂ and / or mixtures thereof.

In a preferred embodiment, metal oxides, metal hydroxides and / or metal oxide hydrates are used as the dielectric high-index layer. The dielectric high-index layer particularly preferably comprises titanium dioxide, iron (III) oxide, goethite, ilmenite, pseudobrookite, pseudorutil and / or mixtures thereof. Very particularly preferably, the dielectric high-index layer comprises titanium dioxide, iron (III) oxide and / or mixtures thereof. In a further embodiment, the dielectric high-index layer consists of the abovementioned compounds or mixtures thereof.

If the surface-modified effect pigments are coated with titanium dioxide, the titanium dioxide may be present in the rutile or anatase crystal modification. Preferably, the titanium dioxide layer is in the rutile form. The rutile form can be obtained, for example, by applying a layer of tin dioxide to the platelet-shaped substrate to be coated, for example, before application of the titanium dioxide layer. On this layer of tin dioxide, titanium dioxide crystallizes in the rutile modification. The tin dioxide may be present as a separate layer, wherein the layer thickness may be a few nanometers, for example less than 10 nm, more preferably less than 5 nm, even more preferably less than 3 nm. The tin dioxide can also be present at least partially in admixture with the titanium dioxide.

Examples of dielectric low-index layers include metal oxides such as silicon oxide, preferably silicon dioxide (SiO ₂ ), aluminum oxide, preferably Al ₂ O ₃ , boron oxide, preferably B ₂ O ₃ , metal fluorides such as magnesium fluoride, preferably MgF ₂ , aluminum fluoride, preferably AlF ₃ , cerium fluoride, preferably CeF ₃ , calcium fluoride, preferably CaF ₂ , metal oxide hydrates such as alumina hydrate (AlOOH), silica hydrate, organic monomers and polymers consisting of, for example, acrylates or methacrylates and / or mixtures of the abovementioned compounds.

In a preferred embodiment, metal oxides, metal oxide hydrates and / or organic dielectric materials are used as the dielectric low-index layer. Preferably, the dielectric low refractive index layer comprises silica, alumina, alumina hydrate and / or acrylates. In another embodiment, the dielectric low refractive index layer is silica, alumina, alumina hydrate, and / or acrylates. More preferably, the dielectric low refractive index layer comprises silicon dioxide.

To increase the light, weather and / or chemical stability, at least one protective layer can furthermore be applied to the at least one dielectric coating. The protective layer may on the one hand comprise metal oxides or metal hydroxides of aluminum, cerium, chromium, silicon, zirconium or mixtures of these metal oxides and / or metal hydroxides. On the other hand, the protective layer may comprise organic polymers consisting of, for example, acrylates or polyethers.

Preferably, in the case of a non-metallic platelet-shaped substrate, the at least one protective layer comprises metal oxides and / or metal hydroxides of chromium, cerium and / or silicon. In the case of a metallic platelet-shaped substrate, the at least one protective layer comprises metal oxides and / or metal hydroxides of silicon and / or organic polymers. In the case of a non-metallic substrate, the at least one protective layer preferably comprises chromium hydroxide, cerium oxide, cerium hydroxide and / or silicon dioxide. In the case of a metallic platelet-shaped substrate, the at least one protective layer preferably comprises silicon dioxide and / or acrylates. In a further embodiment, the at least one protective layer consists of the abovementioned compounds.

In a further embodiment, the at least one protective layer may comprise a single one of the aforementioned compounds. Alternatively, the at least one protective layer may also comprise several of these compounds, which may be present as a mixture or as discrete layers, which preferably follow one another directly.

In another embodiment, the protective layer may at least partially penetrate the dielectric layer to form a mixed layer.

The surface-modified effect pigments suitable for use according to the invention in powder coatings have on the effect pigment surface, d. H. on the dielectric layer or the optional protective layer at least one epoxide group-containing compound. Accordingly, mixtures of different epoxide group-containing compounds can also be present.

The epoxide group-containing compound has at least one epoxide group in the molecule. These may be bonded to saturated or unsaturated, branched or unbranched, substituted or unsubstituted aliphatic or cycloaliphatic, substituted or unsubstituted aromatic or heterocyclic radicals. For example, the epoxide group may be bonded in the molecule via at least one free carboxylic, sulfonic or phosphonic acid group or at least one free hydroxyl group. The epoxide group-containing compound can be both mono- and di-substituted epoxy groups in the Have molecule. Simply substituted epoxide groups are to be understood as meaning those which carry only one radical other than hydrogen. The non-hydrogen moieties of the di-substituted epoxy groups can be in both the 1,1 and 1,2 positions. In a preferred embodiment, the non-hydrogen moieties of the di-substituted epoxide groups are in the 1,2-position. Examples of epoxide group-containing compounds having an epoxide group in the molecule include 1,2-epoxy-3-methoxypropane (930-37-0), 1,2-epoxy-3-ethoxypropane (4016-11-9), 1, 2-epoxy-3-propoxypropane (3126-95-2), 1,2-epoxy-3-isopropoxypropane (4016-14-2), 3-butoxy-1,2-epoxypropane (2426-08-6), 3 tert-butoxy-1,2-epoxypropane (7665-72-7), 1,2-epoxy-3- (isopentyloxy) propane (15965-97-6), 1,2-epoxy-3- (hexyloxy) propane (5926-90-9), 1,2-epoxy-3- [2- (ethylhexyl) oxy] propane (2461-15-6), 1- (cyclohexyloxy) -2,3-epoxypropane (3681-02-5 ), 1,2-epoxy-3- (octyloxy) propane (3385-66-8), 1- (decyloxy) -2,3-epoxypropane (3497-06-1), 4- (2,3-epoxypropoxy) 1-butanol (4711-95-9), 3- (2,3-epoxypropoxy) -1,2-propanediol (25038-04-4), 4 - [(2,3-epoxypropoxy) methyl] -2, 2-dimethyl-1,3-dioxolane (1607-37-0), [(vinyloxy) methyl] oxirane (3678-15-7), 1-allyloxy-2,3-epoxypropane (106-92-3), 2 , 3-epoxypropyl propargyl ether (18180-30-8), 1,2-epoxy-3-phenoxypropane (122-60-1), 1,2-epoxy-3- (2-methylphenoxy) propane (2210-79-9) , 3- (4- tert -butylphenoxy) -1,2-epoxypropane (3101-60-8), 1,2-epoxy-3- (2-methoxyphenoxy) propane (2210-74-4), 1,2-epoxy-3- (4 -methoxyphenoxy) propane (2211-94-1), 1,2-epoxy-3- (4-chlorophenoxy) propane (2212-05-7), 3-benzyloxy-1,2-epoxypropane (2930-5-4) , 1,2-epoxy-3- (4-vinylbenzyloxy) propane (113538-80-0), 2,3-epoxy-1-propyltriphenylmethyl ether (S - (-): 129940-50-7, R - (+) : 65291-30-7)), 3- [4- [1- [4- (2,3-epoxypropoxy) phenyl] -1-methylethyl] phenoxy] propane-1,2-diol (76002-91-0) , 2 - [(1-Naphthyloxy) methyl] oxirane (2461-42-9), 2- (naphthalen-1-ylmethoxymethyl) oxirane (66931-57-5), 2 - [(2,3-epoxypropoxy) methyl] furan (5380-87-0), N- (2,3-epoxypropyl) phthalimide (S - (+): 161596-47-0, R - (-): 181140-34-1), 4- (2, 3-epoxypropoxy) carbazole (51997-51-4), 2,3-epoxypropylacetate (6387-89-9), 2,3-epoxypropylpropionate (37111-25-4), 2,3-epoxypropyl-n-butyrate (2461 -40-7), 2,3-epoxypropyl laurate (1984-77-6), 2,3-epoxypropyl acrylate (106-90-1), 2,3-epoxypropyl methacrylate (106-91-2), 4- (2, 3-epoxypropoxy) butyl acrylate (119692-59-0), Styrolox id (96-09-3), 3,4-epoxy-1-butadiene (930-22-3), 2,3-epoxy-1-propanol (556-52-5), 3-oxiranylpropenal (E: 25073 -24-9, Z: 25073-23-8), 1-oxiranylethanone (4401-11-0), 3- (oxiran-2-yl) propyl acetate (59287-65-9), methyl 3,4-epoxybutyrate (4509-09-5), 1,2-epoxybutyronitrile (6509-08-6), oxiran-2-ylmethoxyphosphonic acid (23815-70-5), (3-methyloxiran-2-yl) phosphonic acid (23155-02 -4), oxiran-2-ylmethyl-4-methylbenzenesulfonate (6746-81-2) or oxiran-2-ylmethyl-3-nitrobenzenesulfonate (R - (-): 115314-17-5).

Preferably, as epoxide group-containing compounds which have only one epoxide group in the molecule, 1,2-epoxy-3-methoxypropane (930-37-0), 1,2-epoxy-3-ethoxypropane (4016-11-9), 1, 2-epoxy-3-propoxypropane (3126-95-2), 1,2-epoxy-3-isopropoxypropane (4016-14-2), 3-tert-butoxy-1,2-epoxypropane (7665-72-7) , 1,2-epoxy-3- (isopentyloxy) propane (15965-97-6), 1,2-epoxy-3- (hexyloxy) propane (5926-90-9), 1- (cyclohexyloxy) -2,3 -epoxypropane (3681-02-5), 1,2-epoxy-3- (octyloxy) propane (3385-66-8), 4- (2,3-epoxypropoxy) -1-butanol (4711-95-9) , 3- (2,3-Epoxypropoxy) -1,2-propanediol (25038-04-4), 4 - [(2,3-epoxypropoxy) methyl] -2,2-dimethyl-1,3-dioxolane (1607 -37-0), [(vinyloxy) methyl] oxirane (3678-15-7), 1-allyloxy-2,3-epoxypropane (106-92-3), 2,3-epoxypropyl propargyl ether (18180-30-8) , 1,2-epoxy-3- (2-methoxyphenoxy) propane (2210-74-4), 1,2-epoxy-3- (4-methoxyphenoxy) propane (2211-94-1), 3-benzyloxy-1 , 2-epoxypropane (2930-5-4), 1,2-epoxy-3- (4-vinylbenzyloxy) propane (113538-80-0), 3- [4- [1- [4- (2,3-) epoxypropoxy) phenyl] 1-methylethyl] phenoxy] propane-1,2-diol (76002-91-0), 2,3-epoxypropyl acrylate (106-90-1), 4- (2,3-epoxypropoxy) butyl acrylate (119692-59- 0), 2,3-epoxy-1-propanol (556-52-5), 3-oxiranylpropenal (E: 25073-24-9, Z: 25073-23-8), 1-oxiranylethanone (4401-11-0 ), 3- (oxiran-2-yl) propyl acetate (59287-65-9), methyl 3,4-epoxybutyrate (4509-09-5), 1,2-epoxybutyronitrile (6509-08-6), oxirane 2-ylmethoxyphosphonic acid (23815-70-5), (3-methyloxiran-2-yl) phosphonic acid (23155-02-4) and / or mixtures thereof.

Particular preference is given to epoxide-containing compounds which have only one epoxide group in the molecule, 1,2-epoxy-3-methoxypropane (930-37-0), 1,2-epoxy-3-ethoxypropane (4016-11-9), 1 , 2-epoxy-3-propoxypropane (3126-95-2), 1,2-epoxy-3-isopropoxypropane (4016-14-2), 3-tert-butoxy-1,2-epoxypropane (7665-72-7 ), 1- (cyclohexyloxy) -2,3-epoxypropane (3681-02-5), [(vinyloxy) methyl] oxirane (3678-15-7), 1-allyloxy-2,3-epoxypropane (106-92- 3), 2,3-epoxypropyl propargyl ether (18180-30-8), 1,2-epoxy-3- (4-vinylbenzyloxy) propane (113538-80-0), 2,3-epoxypropyl acrylate (106-90-1) , 4- (2,3-epoxypropoxy) butyl acrylate (119692-59-0), 3-oxiranylpropenal (E: 25073-24-9, Z: 25073-23-8), 3- (oxiran-2-yl) propyl acetate (59287-65-9), oxiran-2-ylmethoxyphosphonic acid (23815-70-5) and / or mixtures thereof.

In a preferred embodiment, the epoxide group-containing compound has at least two epoxide groups in the molecule.

In a further embodiment, the epoxide group-containing compound has two or three epoxide groups in the molecule.

When using an epoxide group-containing compound having at least two or three epoxide groups in the molecule, covalent attachment of the epoxide group-containing compound can take place by reacting an epoxide group with the effect pigment surface, for example a hydroxyl group on the effect pigment surface. The at least one further epoxy group can then enter into a covalent bond with the binder component of the powder coating in the powder coating.

The epoxide group-containing compounds which have at least two epoxide groups in the molecule include, for example, bis (2,3-epoxypropyl) ether (2238-07-5), 1,2-bis (2,3-epoxypropoxy) ethane (2,224-15). 9), 1,4-bis (2,3-epoxypropoxy) butane (2425-79-8), 1,3-bis (2,3-epoxypropoxy) butane (3332-48-7), 1,5-bis (2,3-epoxypropoxy) pentane (7517-06-8), 1,3-bis (2,3-epoxypropoxy) -2,2-dimethylpropane (17557-23-2), 1,6-bis (2, 3-epoxypropoxy) hexane (16096-31-4), 1,2-bis (2,3-epoxypropoxy) cyclohexane (37763-26-1), 1,4-bis [(2,3-epoxypropoxy) methyl] cyclohexane (14228-73-0), 1,3-bis (oxiran-2-ylmethoxy) propan-2-ol (3568-29-4), bis [2- (2,3-epoxypropoxy) ethyl] ether (4206- 61-5), 2,2 '- [oxybis [(methyl-2,1-ethanediyl) oxymethylene]] bisoxirane (41638-13-5), PEG-400-DGE (39443-66-8, Raschig) , PPG-DGE / PPG-DGE 200 (26142-30-3, 30401-87-7, Raschig), 1,2,3-tris (2,3-epoxypropoxy) propane (13236-02-7), 1- (2,3-epoxypropoxy) -2,2-bis [(2,3-epoxypropoxy) methyl] butane (3454-29-3), 2- [3- [1,3-bis [3- (oxirane -2-ylmethoxy) propoxy] propan-2 -yloxy] propoxymethyloxirane (37237-76-6), 1,3-bis (2,3-epoxypropoxy) -2,2-bis [(2,3-epoxypropoxy) methyl] propane (3126-63-4), GE 500 (118549-88-5, 118606-72-7, 16268-64-0, 191548-99-9, Raschig), 1,3-bis (2,3-epoxypropoxy) benzene (101-90-6 4,4'-bis (2,3-epoxypropoxy) biphenyl (2461-46-3), 2,2-bis [4- (2,3-epoxypropoxy) phenyl] propane (1675-54-3), 2,6-bis (2,3-epoxypropyl) phenyl-2,3-epoxypropyl ether (13561-08-5), 2,2 ', 2' '- [methylidynetris (phenyleneoxymethylene)] trisoxirane (66072-38-6) , 2,2 ', 2' '- [ethylidynetris (4,1-phenyleneoxymethylene)] trisoxirane (87093-13-8), 1,1,2,2-tetrakis [4- (oxiranylmethoxy) phenyl] ethane (7328- 97-4), N, N-bis (2,3-epoxypropyl) aniline (2095-06-9), 4- (2,3-epoxypropoxy) -N, N-bis (2,3-epoxypropyl) aniline ( 5026-74-4), 2,4,6-tris (oxiran-2-ylmethoxy) -1,3,5-triazine (2589-01-7), tris (2,3-epoxypropyl) -1,3, 5-triazine-2,4,6-trione (2451-62-9), bis (oxiran-2-ylmethyl) oxalate (60468-47-5), bis (2,3-epoxypropyl) malonate (60468-48- 6), bis (2,3-epoxypropyl) -2,2-dimethylglutarate (25677-88-7), bis (2,3-epoxypropyl) l) adipate (2754-27-0), bis (2,3-epoxycyclohexylmethyl) adipate (3130-19-6), bis (2,3-epoxypropyl) cyclohexane-1,2-dicarboxylate (5493-45-8) , Bis (2,3-epoxypropyl) cyclohexene-1,2-dicarboxylate (21544-03-6), bis (2,3-epoxypropyl) phthalate (7195-45-1), bis (2,3-epoxypropyl) terephthalate (7195-44-0), tris (2,3-epoxypropyl) trimellitate (7237-83-4), 2-methyl-2,2'-bioxirane (6341-85-1), 1,2,5,6 -Iehexoxyhexane (1888-89-7), 1,2,7,8-diepoxyoctane (2426-07-5), 1,2,8,9-diepoxynonane (24829-11-6), 1,2,9, 10-Diepoxydecane (24854-67-9), m-bis (epoxyethyl) benzene (16832-59-0), bis (2,3-epoxycyclopentyl) ether (2386-90-5), N, N-bis (2 , 3-epoxypropyl) cyclohexylamine (13391-15-6), N, N-bis (2,3-epoxypropyl) isopropylamine (19115-57-2), (3,4-epoxycyclohexyl) methyl-3,4-epoxycyclohexylcarboxylate ( 2386-87-0) and / or tris (2,3-epoxypropyl) phosphate (18795-33-0).

Preference is given as epoxide group-containing compounds which have at least two epoxide groups in the molecule, bis (2,3-epoxypropyl) ether (2238-07-5), 1,2-bis (2,3-epoxypropoxy) ethane (2224-15-9 ), 1,4-bis (2,3-epoxypropoxy) butane (2425-79-8), 1,3-bis (2,3-epoxypropoxy) butane (3332-48-7), 1,5-bis ( 2,3-epoxypropoxy) pentane (7517-06-8), 1,3-bis (2,3-epoxypropoxy) -2,2-dimethylpropane (17557-23-2), 1,6-bis (2,3 -epoxypropoxy) hexane (16096-31-4), 1,2-bis (2,3-epoxypropoxy) cyclohexane (37763-26-1), 1,4-bis [(2,3-epoxypropoxy) methyl] cyclohexane ( 14228-73-0), 1,3-bis (oxiran-2-ylmethoxy) propan-2-ol (3568-29-4), bis [2- (2,3-epoxypropoxy) ethyl] ether (4206-61 -5), 2,2 '- [oxybis [(methyl-2,1-ethanediyl) oxymethylene]] bisoxirane (41638-13-5), 1,2,3-tris (2,3-epoxypropoxy) propane (13236 -02-7), 1- (2,3-epoxypropoxy) -2,2-bis [(2,3-epoxypropoxy) methyl] butane (3454-29-3), 2- [3- [1,3- Bis [3- (oxiran-2-ylmethoxy) propoxy] propan-2-yloxy] propoxymethyloxirane (37237-76-6), 1,3-bis (2,3-epoxypropoxy) -2,2-bis [(2, 3-epoxypropoxy) methyl] propane ( 3126-63-4), 1,3-bis (2,3-epoxypropoxy) benzene (101-90-6), 4,4'-bis (2,3-epoxypropoxy) biphenyl (2461-46-3), 2,2-bis [4- (2,3-epoxypropoxy) phenyl] propane (1675-54-3), 2,6-bis (2,3-epoxypropyl) phenyl-2,3-epoxypropyl ether (13561-08- 5), 2,2 ', 2' '- [methylidynetris (phenyleneoxymethylene)] trisoxirane (66072-38-6), 2,2', 2 '' - [ethylidynetris (4,1-phenyleneoxymethylene)] trisoxirane (87093- 13-8), 1,1,2,2-tetrakis [4- (oxiranylmethoxy) phenyl] ethane (7328-97-4), N, N-bis (2,3-epoxypropyl) aniline (2095-06-9 ), 4- (2,3-epoxypropoxy) -N, N-bis (2,3-epoxypropyl) aniline (5026-74-4), tris (2,3-epoxypropyl) -1,3,5-triazine 2,4,6-trione (2451-62-9), bis (oxiran-2-ylmethyl) oxalate (60468-47-5), bis (2,3-epoxypropyl) malonate (60468-48-6), bis (2,3-epoxypropyl) -2,2-dimethylglutarate (25677-88-7), bis (2,3-epoxypropyl) adipate (2754-27-0), bis (2,3-epoxycyclohexylmethyl) adipate (3130- 19-6), bis (2,3-epoxypropyl) cyclohexane-1,2-dicarboxylate (5493-45-8), bis (2,3-epoxypropyl) cyclohexene-1,2-dicarboxylate (21544-03-6) , Bis (2,3-epoxypropyl) phthalate (7195-45-1), 2- Methyl 2,2'-bioxirane (6341-85-1), 1,2,5,6-diepoxyhexane (1888-89-7), 1,2,7,8-diepoxyoctane (2426-07-5), 1,2,8,9-diepoxynonane (24829-11-6), 1,2,9,10-diepoxydecane (24854-67-9), m-bis (epoxyethyl) benzene (16832-59-0), bis (2,3-epoxycyclopentyl) ether (2386-90-5), N, N-bis (2,3-epoxypropyl) cyclohexylamine (13391-15-6), N, N-bis (2,3-epoxypropyl) isopropylamine (19115-57-2), (3,4-epoxycyclohexyl) methyl-3,4-epoxycyclohexylcarboxylate (2386-87-0) and / or tris (2,3-epoxypropyl) phosphate (18795-33-0).

Particular preference is given to epoxide-group-containing compounds which have at least two epoxide groups in the molecule, bis (2,3-epoxypropyl) ether (2238-07-5), 1,3-bis (2,3-epoxypropoxy) butane (3332-48). 7), 1,5-bis (2,3-epoxypropoxy) pentane (7517-06-8), 1,2-bis (2,3-epoxypropoxy) cyclohexane (37763-26-1), 1,3-bis (oxiran-2-ylmethoxy) propan-2-ol (3568-29-4), bis [2- (2,3-epoxypropoxy) ethyl] ether (4206-61-5), 2,2 '- [oxybis [ (methyl-2,1-ethanediyl) oxymethylene]] bisoxirane (41638-13-5), 1,2,3-tris (2,3-epoxypropoxy) propane (13236-02-7), 2- [3- [ 1,3-bis [3- (oxiran-2-ylmethoxyl) propoxy] propan-2-yloxy] propoxymethyloxirane (37237-76-6), 2,6-bis (2,3-epoxypropyl) phenyl-2,3- epoxypropyl ether (13561-08-5), 2,2 ', 2''- [methylidynetris (phenyleneoxymethylene)] trisoxirane (66072-38-6), 2,2', 2 '' - [ethylidynetris (4,1-phenyleneoxymethylene )] trisoxirane (87093-13-8), 1,1,2,2-tetrakis [4- (oxiranylmethoxy) phenyl] ethane (7328-97-4), bis (oxiran-2-ylmethyl) oxalate (60468-47 -5), bis (2,3-epoxypropyl) malonate (60468-48-6), bis (2,3-epoxypropyl) -2 , 2-dimethylglutarate (25677-88-7), bis (2,3-epoxycyclohexylmethyl) adipate (3130-19-6), bis (2,3-epoxypropyl) cyclohexene-1,2-dicarboxylate (21544-03-6 ), 2-methyl-2,2'-bioxirane (6341-85-1), 1,2,5,6-diepoxyhexane (1888-89-7), 1,2,7,8-diepoxyoctane (2426-07 -5), 1,2,8,9-diepoxynonane (24829-11-6), 1,2,9,10-diepoxydecane (24854-67-9), (3,4-epoxycyclohexyl) methyl-3,4 epoxycyclohexylcarboxylate (2386-87-0), tris (2,3-epoxypropyl) phosphate (18795-33-0) and / or mixtures thereof.

Very particular preference is given to epoxide group-containing compounds which have at least two epoxide groups in the molecule, bis (2,3-epoxypropyl) ether (2238-07-5), 1,3-bis (2,3-epoxypropoxy) butane (3332-48 -7), 1,5-bis (2,3-epoxypropoxy) pentane (7517-06-8), 1,2,3-tris (2,3-epoxypropoxy) propane (13236-02-7), 2, 6-Bis (2,3-epoxypropyl) phenyl-2,3-epoxypropyl ether (13561-08-5), bis (oxiran-2-ylmethyl) oxalate (60468-47-5), bis (2,3-epoxypropyl) malonate (60468-48-6), bis (2,3-epoxypropyl) -2,2-dimethylglutarate (25677-88-7), bis (2,3-epoxycyclohexylmethyl) adipate (3130-19-6), 2- Methyl 2,2'-bioxirane (6341-85-1), 1,2,5,6-diepoxyhexane (1888-89-7), 1,2,7,8-diepoxyoctane (2426-07-5), (3,4-epoxycyclohexyl) methyl-3,4-epoxycyclohexylcarboxylate (2386-87-0), tris (2,3-epoxypropyl) phosphate (18795-33-0) and / or mixtures thereof.

Particular preference is given to epoxide-group-containing compounds which have at least two epoxide groups in the molecule, bis (2,3-epoxypropyl) ether (2238-07-5), 1,3-bis (2,3-epoxypropoxy) butane (3332-48 -7), 1,2,3-tris (2,3-epoxypropoxy) propane (13236-02-7), 2,6-bis (2,3-epoxypropyl) phenyl-2,3-epoxypropyl ether (13561-08 -5), bis (oxiran-2-ylmethyl) oxalate (60468-47-5), bis (2,3-epoxypropyl) malonate (60468-48-6), bis (2,3-epoxycyclohexylmethyl) adipate (3130- 19-6), 1,2,5,6-diepoxyhexane (1888-89-7), tris (2,3-epoxypropyl) phosphate (18795-33-0) and / or mixtures thereof.

The information in brackets refers to the associated CAS numbers.

According to a further embodiment, a mixture of different epoxide group-containing compounds is applied to the effect pigment surface. In this case, for example, one or more epoxide group-containing compound (s) having only one epoxide group with one or more epoxide group-containing compound (s) having at least two epoxide groups may be applied together to the effect pigment surface.

According to the invention, the epoxy group-containing compound used as starting material has no silane-functional group. Pigments which are surface-modified with epoxide group-containing compounds having in addition to the epoxide group at least one silane functional group in the molecule are not compatible with the surrounding powder coating for reasons not previously understood. This manifests itself in strong adhesions of these pigments on the baffle plate and on the electrode of the powder paint gun, which leads to a separation of pigment and powder coating. Occurring Lackierfehler in the form of pigment agglomerates on the substrate to be coated and a concomitant, insufficient recyclability of the overspray are the result. Furthermore, powder coatings which contain such surface-modified effect pigments have an insufficient coating of the substrate edges during application, which leads to an increased susceptibility to corrosion.

The epoxide group-containing compound can be applied to the dielectric layer or the optional protective layer by mixing the at least one epoxide group-containing compound with the respective effect pigment, if appropriate in the presence of a solvent, and then drying it. In this case, ≦ 10% by weight, based on the total weight of the surface-modified effect pigment, of at least one compound containing epoxide groups is applied to the dielectric layer or the optionally present protective layer. Preferably, the amount of the at least one epoxy group-containing compound used is in a range of 0.5 to 8 wt .-%, more preferably in a range of 0.6 to 6 wt .-%, particularly preferably in a range of 0.7 to 5 wt .-% and especially preferably in a range of 0.8 to 4 wt .-%, each based on the total weight of the surface-modified effect pigment.

The epoxide group-containing compound is not applied to the dielectric layer or the optional protective layer by the spray-drying method. The spray drying process is described in WO 2006/136435 A2 or in the WO 2005/063897 A2 described.

The epoxide group-containing compound can be bonded to the dielectric layer or the optional protective layer via the at least one epoxy group. According to the invention, it is preferred that at least a portion of the epoxide groups of the at least one epoxide group-containing compound is retained on the effect pigment surface to permit reaction with the powder coating components. Each free epoxide group may serve to further crosslink the epoxide group-containing compounds with each other and / or to react with the binder component of the powder coating.

The epoxide group-containing compounds preferably have an epoxide equivalent weight in the range from 15 to 15,000 and more preferably in the range from 20 to 10,000. Most preferably, the epoxide group-containing compounds have an epoxide equivalent weight in the range from 22 to 7000 or from a range of 30 to 800 on.

The epoxide equivalent weight is understood to mean the amount of epoxide group-containing compound in grams which contains 16 grams of epoxide-bonded oxygen (epoxide oxygen). The determination is carried out, as known to those skilled in the art, by titration with cetyltrimethylammonium bromide under acidic conditions.

The effect pigments surface-modified with an epoxide group-containing compound have a specific epoxide equivalent weight in a range from 119,000 to 800, preferably from a range from 115,000 to 900, and more preferably from a range from 114,000 to 1,000. With very particular preference the surface-modified effect pigments have a specific epoxide equivalent weight in the range from 106,000 to 2,500.

The specific epoxide equivalent weight is understood to mean the amount of pigment in grams which contains 16 grams of epoxide oxygen (epoxide oxygen).

The larger the numerical value of the specific epoxide equivalent weight, the lower the number of free epoxide groups on the effect pigment surface. This has the consequence that less free epoxide groups are available for crosslinking with the surrounding binder of the powder coating.

The determination of the specific epoxide equivalent weight is carried out in accordance with the determination of the epoxide equivalent weight of the compound containing epoxide groups by titration. In addition, the amine number of the non-surface-modified effect pigment must be determined.

The average diameter of the effect pigments, indicated as D _{50 of} the surface-modified effect pigments, is preferably in a range from 2.0 μm to 100 μm, preferably in a range from 2.5 μm to 75 μm, more preferably in a range from 3.0 microns to 50 microns, more preferably in a range of 3.5 microns to 35 microns and most preferably in a range of 4.2 to 24 microns.

The D ₉₀ value of the diameter of the effect pigments is preferably in a range of 8 to 290 μm, more preferably in a range of 10 to 240 μm, still more preferably in a range of 19 to 155 μm, particularly preferably in a range of 24 to 90 microns and most preferably in a range of 16 to 47 microns.

In the above information, the range specifications of the D ₅₀ or D ₉₀ values preferably correlate with one another in the respectively indicated sequence, ie the respective first values, the second values, the third values and the fourth values, respectively.

The D ₁₀ , D ₅₀ , or D ₉₀ value of the cumulative frequency distribution of the volume-averaged size distribution function as obtained by laser diffraction methods indicates that 10%, 50%, and 90% of the surface modified effect pigments have a diameter equal to or equal to is less than the specified value. Here, the size distribution curve with a device from the company. Malvern (device: MALVERN Mastersizer 2000) according to the manufacturer's instructions. The evaluation of the scattered light signals was carried out according to the Mie theory, which also includes refractive and absorption behavior of the particles.

In a further embodiment, the present invention comprises the use of surface-modified pearlescent pigments in a powder coating, wherein the surface-modified pearlescent pigments based on a platelet-shaped transparent substrate comprise at least one dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound.

In a further embodiment, the present invention comprises the use of surface-modified pearlescent pigments in a powder coating, wherein the surface-modified pearlescent pigments based on a platelet-shaped transparent substrate comprise at least one optically active layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound.

In a further embodiment, the present invention comprises the use of surface-modified pearlescent pigments in a powder coating, the surface-modified pearlescent pigments based on flake-form natural or synthetic mica comprising at least one dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound which does not contain silicon atoms in the Contains molecule include.

In a further embodiment, the present invention comprises the use of surface-modified pearlescent pigments in a powder coating, wherein the surface-modified pearlescent pigments based on flake-form natural or synthetic mica comprise at least one dielectric layer, optionally at least one protective layer consisting of metal oxides and / or metal hydroxides, and a surface modification with at least an epoxide group-containing compound having at least two epoxide groups.

In a further embodiment, the present invention comprises the use of surface-modified pearlescent pigments in a powder coating, wherein the surface-modified pearlescent pigments based on flake-form natural or synthetic mica comprise at least one dielectric layer consisting of metal oxides and / or metal hydroxides, optionally at least one protective layer consisting of metal oxides and / or or metal hydroxides, as well as a surface modification with at least one epoxide group-containing compound having at least two epoxide groups, without silicon atoms in the molecule.

In a further embodiment, the present invention comprises the use of surface-modified pearlescent pigments in a powder coating, wherein the surface-modified pearlescent pigments based on a platelet-shaped substrate comprise at least one dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound, and wherein the surface-modified pearlescent pigments specific epoxide equivalent weight ranging from 119,000 to 800.

In a further embodiment, the present invention comprises the use of surface-modified pearlescent pigments in a powder coating, wherein the surface-modified pearlescent pigments based on glass flakes comprise at least one dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound.

In a further embodiment, the present invention comprises the use of surface-modified pearlescent pigments in a powder coating, wherein the surface-modified pearlescent pigments based on glass flakes comprise at least one dielectric layer, optionally at least one protective layer consisting of metal oxides and / or metal hydroxides, and a surface modification with at least one epoxide group-containing compound at least two epoxide groups.

In a further embodiment, the present invention comprises the use of surface-modified metallic effect pigments in a powder coating, wherein the surface-modified metallic effect pigments based on a platelet-shaped substrate comprise at least one dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound.

In a further embodiment, the present invention comprises the use of surface-modified metallic effect pigments in a powder coating, wherein the surface-modified metallic effect pigments based on a platelet-shaped substrate comprise at least one dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound having at least two epoxide groups.

In a further embodiment, the present invention comprises the use of surface-modified metallic effect pigments in a powder coating, wherein the surface-modified metallic effect pigments based on flaky aluminum comprise at least one dielectric layer, optionally at least one protective layer, and an outer layer with at least one epoxide group-containing compound.

In a further embodiment, the present invention comprises the use of surface-modified metallic effect pigments in a powder coating, wherein the surface-modified metallic effect pigments based on flaky aluminum comprise at least one dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound having at least two epoxide groups.

In a further embodiment, the present invention comprises the use of surface-modified metallic effect pigments in a powder coating, wherein the surface-modified metallic effect pigments based on platelet-based aluminum comprise at least one dielectric layer consisting of an acrylate, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound.

In a further embodiment, the present invention comprises the use of surface-modified metallic effect pigments in a powder coating, wherein the surface-modified metallic effect pigments based on flaky aluminum comprise at least one dielectric layer consisting of silicon dioxide, optionally at least one protective layer consisting of an acrylate, and a surface modification with at least one epoxy group-containing Compound having at least two epoxy groups which does not contain silicon atoms in the molecule.

In a further embodiment, the present invention comprises the use of surface-modified metallic effect pigments in a powder coating, the surface-modified metallic effect pigments based on platelet-shaped copper comprising at least one dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound.

In a further embodiment, the present invention comprises the use of surface-modified metallic effect pigments in a powder coating, wherein the platelet-shaped copper-based surface-modified metallic effect pigments comprise at least one dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound having at least two epoxide groups.

In a further embodiment, the present invention comprises the use of surface-modified metallic effect pigments in a powder coating, wherein the surface-modified metallic effect pigments based on a platelet-shaped substrate comprise at least one dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound, and wherein the surface-modified metallic effect pigments specific epoxide equivalent weight ranging from 99,000 to 800.

In a further embodiment, the present invention comprises a powder-coated article comprising a powder coating comprising surface-modified effect pigments having a specific epoxide equivalent weight in the range from 119,000 to 800.

In a further embodiment, the present invention comprises surface-modified effect pigments based on a platelet-shaped substrate which is coated with at least one dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound having an epoxide equivalent weight in the range from 10 to 20,000.

In a further embodiment, the present invention comprises surface-modified pearlescent pigments based on natural or synthetic mica, which is coated with at least one dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound having an epoxide equivalent weight in the range from 10 to 20,000.

In a further embodiment, the present invention comprises surface-modified metallic effect pigments based on flaky aluminum, which is coated with at least one dielectric layer, optionally at least one protective layer, and with surface modification with at least one epoxide group-containing compound having an epoxide equivalent weight in the range from 10 to 20,000.

In addition to the described surface-modified effect pigments, powder coatings may also contain organic and / or inorganic color pigments and / or colorants and / or further effect pigments in order to achieve special color effects.

The described surface-modified effect pigments are particularly suitable for the pigmentation of powder coatings, which are produced by the dry blend process. The segregation of effect pigment and powder coating, which is frequently observed here during application, can be largely avoided by using the surface-modified effect pigments described. If the surface-modified effect pigments to be used according to the invention are mixed with a powder coating by the dry blend method and then applied by the corona method, it is possible to almost completely prevent adhesion of the effect pigments to the electrode (s) and impact plate of the powder coating gun. In particular, there is virtually no adhesion at least over a period of 20 s at 100 kV and 100 μA application voltage.

If it comes to pigment attachments, these grow with time and are then entrained with the conveying air. This can on the one hand on the substrate to be coated to Lackierfehlern in the form of z. As pigment agglomerates and on the other in the overspray lead to a pigment enrichment, which would result in color and / or effect shifts in a reuse of the overspray. The use of the surface-modified effect pigments to be used according to the invention makes it possible to obtain powder coatings without coating defects which are caused by the described adhesions. In addition to the paint defects described, black, microscopically small defects, so-called "black spots", which occur in powder coatings, can also be avoided by using the surface-modified effect pigments to be used according to the invention. Of course, the surface-modified effect pigments to be used according to the invention can also be used in powder coatings which are produced by the bonding method.

Powder coatings which contain the surface-modified effect pigments to be used according to the invention are distinguished by the fact that they lead to a good coating of the edges in the baked state after the coating process. An edge escape can thus not be observed.

Furthermore, good fluidizability of the powder coating according to the invention, which contain these surface-modified effect pigments, is given.

The pigmentation of the powder coatings according to the invention with the surface-modified effect pigments to be used according to the invention is in a range of ≦ 10% by weight, preferably in a range of from 0.5 to <8.0% by weight, particularly preferably in a range of 0, 7 to <6 wt .-% and most preferably in a range of 1.0 to ≤ 5 wt .-%, each based on the total weight of the pigmented powder coating.

In addition to the surface-modified effect pigments mentioned, the powder coatings according to the invention may additionally contain charge additives and / or trickle agents, such as, for example, B. pyrolytically produced alumina or pyrolytically produced silica may be added. These can positively influence the flow behavior of the powder coating.

Powder coatings containing surface-modified effect pigments may be suitable not only indoors but also for outdoor applications. Surface-modified effect pigments which are used in powder coatings for outdoor use, should a weather-stabilized effect pigment precursor such. For example, the commercially available Phoenix XT series, the Phoenix CFE series or even the LUXAN CFX series from Eckart GmbH included. The weather-stable effect pigment precursors can, for example, analogously to EP 1 682 622 B1 and are characterized by excellent UV and weather stability.

An important criterion in addition to the weather resistance is the cleanability of powder-coated building facades ( Hans Pfeifer, Journal of Surface Technology 01/2003, p. 24-27 ). For examining the facade cleaning ability, for example, a hand cleaning method can be used. For this purpose, a square tube with a soft cloth, which contains a cleaning solution wrapped. This square tube is moved back and forth on the painted object to be checked without pressure. The result is then visually appraised. Powder coatings containing the surface-modified effect pigments to be used according to the invention are distinguished by an improved cleanability compared to the corresponding effect pigments without the described surface modification.

Furthermore, the surface-modified effect pigments can also be used in other solvent-free coating compositions, in particular in toners. The invention thus also includes toners which contain the surface-modified effect pigments. The invention further includes articles which are printed with a toner containing the surface-modified effect pigments. Articles printed with the toner according to the invention are, for example, printed paper, cardboard or films.

In a further embodiment, the present invention relates to the use of surface-modified effect pigments in toners, wherein the surface-modified effect pigments based on a platelet-shaped substrate comprise a dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound.

In a further embodiment, the present invention relates to the use of surface-modified effect pigments in toners, wherein the surface-modified effect pigments based on a platelet-shaped substrate comprise a dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound having at least two epoxide groups.

In a further embodiment, the present invention relates to a toner containing surface-modified effect pigments, wherein the surface-modified effect pigments based on a platelet-shaped substrate comprise a dielectric layer, optionally at least one protective layer, and an outer layer with at least one epoxide group-containing compound.

In a further embodiment, the present invention relates to a toner containing surface-modified effect pigments, wherein the surface-modified effect pigments based on a platelet-shaped substrate comprise a dielectric layer, optionally at least one protective layer, and a surface modification with at least one epoxide group-containing compound having at least two epoxide groups.

In the following, the invention will be described in more detail by means of examples without wishing to be limited thereto. The surface-modified effect pigments were used in various commercially available powder coatings.

I. Surface-modified effect pigments for use in powder coatings

Inventive Example 1:

150 g of commercially available weather-stabilized silver pearlescent pigment based on natural mica (Phoenix XT 3001, Eckart GmbH) were presented in a laboratory kneader from IKA. At the same time, 3.1 g of epoxide group-containing compound (Cyracure 6110, Dow Corning, epoxide equivalent weight 131 to 143) were dissolved in 60 g of ethanol having an H ₂ O content of 25% by weight and then mixed with the pigment in the kneader. After mixing for 20 minutes, the batch was dried at 120 ° C. The resulting surface-modified effect pigment with a specific epoxide equivalent weight of 118,000 served as starting material for the subsequent powder coating applications.

Inventive Example 2:

150 g of commercially available silver pearlescent pigment based on natural mica (Phoenix PX 3001, Eckart GmbH) were presented in a laboratory kneader from IKA. At the same time, 3.5 g of epoxide group-containing compound (GE 100, Raschig, epoxide equivalent weight 140 to 170) were dissolved in 60 g of ethanol with an H ₂ O content of 35% by weight and then mixed with the pigment in the kneader. After mixing for 20 minutes, the batch was dried at 100 ° C. The resulting surface modified effect pigment with a specific epoxide equivalent weight of 106,000 served as the starting material for the subsequent powder coating applications.

Inventive Example 3:

150 g of commercially available weather-stabilized silver pearlescent pigment based on natural mica (Phoenix XT 3001, Eckart GmbH) were presented in a laboratory kneader from IKA. At the same time, 4.1 g of epoxide group-containing compound (GE 500, Raschig, epoxide equivalent weight 160 to 180) were dissolved in 60 g of ethanol having an H ₂ O content of 35% by weight and then mixed with the pigment in the kneader. After mixing for 20 minutes, the batch was dried at 120 ° C. The resulting surface-modified effect pigment with a specific epoxide equivalent weight of 62,000 served as starting material for the subsequent powder coating applications.

Inventive Example 4:

150 g of commercially available stabilized aluminum pigment (standard special PCU 3500, Eckart GmbH) were presented in a laboratory kneader from IKA. In parallel, 2.5 g of epoxide-containing compound (Cyracure 6105, Dow Corning, epoxy equivalent weight 130 to 135) were dissolved in 60 g of ethanol with an H ₂ O content of 8 wt .-% and then mixed with the pigment in the kneader. After mixing for 20 minutes, the batch was dried at 100 ° C. The resulting surface-modified effect pigment with a specific epoxide equivalent weight of 9200 served as starting material for the subsequent powder coating applications.

Inventive Example 5:

100 g of commercially available, silver pearlescent pigment based on TiO ₂ -coated mica with a fineness of 5-25 μm (PHOENIX PX 2001, Eckart) were suspended in 300 ml of isopropanol and brought to the boiling point. With stirring, initially 2.0 g of H ₂ O and then within one hour a solution of 2.17 g of Ce (NO ₃ ) ₃ in 100 g of isopropanol was added. Subsequently, a solution of 0.45 g of ethylenediamine in 3.0 g of H ₂ O was added. Then, over a period of 2 hours, 10.6 g of tetraethoxysilane and 22 g of isopropanol were introduced continuously by means of a metering pump. Then the suspension was allowed to react for a further 6 hours. The mixture was stirred at room temperature overnight and filtered on a Buchner funnel the next day. The pigment filter cake was submitted in a laboratory kneader Fa. IKA. At the same time, 2.5 g of epoxide group-containing compound (Cyracure 6107, Dow Corning, epoxide equivalent weight 131 to 140) were dissolved in 30 g of isopropanol with an H ₂ O content of 10% by weight and then mixed with the pigment in the kneader. After mixing for 20 minutes, the batch was dried at 120 ° C. The resulting surface-modified effect pigment with a specific epoxide equivalent weight of 20,000 served as starting material for the subsequent powder coating applications.

In the following comparative examples, the effect pigments to be used in a powder coating are mentioned.

Comparative Example 1

Phoenix XT 3001 (Eckart GmbH): commercially available weather-stabilized silver pearlescent pigment based on natural mica

Comparative Example 2:

Phoenix PX 3001 (Eckart GmbH): commercially available silver pearlescent pigment based on natural mica

Comparative Example 3

100 g of commercially available silver pearlescent pigment based on TiO ₂ -coated mica of fineness 1-15 μm (PHOENIX PX 3001, Eckart) were suspended in 300 ml of isopropanol and brought to the boiling point. With stirring, initially 2.0 g of H ₂ O and then within one hour a solution of 2.17 g of Ce (NO ₃ ) ₃ in 100 g of isopropanol was added. Subsequently, a solution of 0.45 g of ethylenediamine in 3.0 g of H ₂ O was added. Then, over a period of 2 hours, 10.6 g of tetraethoxysilane and 22 g of isopropanol were introduced continuously by means of a metering pump. Then the suspension was allowed to react for a further 6 hours. The mixture was stirred overnight at room temperature and filtered the next day through a Buchner funnel. The pigment filter cake was dried at 120 ° C in a vacuum oven. The resulting effect pigment served as comparison material for the subsequent powder coating applications.

Comparative Example 4

100 g of commercially available silver pearlescent pigment based on TiO ₂ -coated mica of fineness 1-15 μm (PHOENIX PX 3001, Eckart) were suspended in 300 ml of isopropanol and brought to the boiling point. With stirring, initially 2.0 g of H ₂ O and then within one hour a solution of 2.17 g of Ce (NO ₃ ) ₃ in 100 g of isopropanol was added. Subsequently, a solution of 0.45 g of ethylenediamine in 3.0 g of H ₂ O was added. Then, over a period of 2 hours, 10.6 g of tetraethoxysilane and 22 g of isopropanol were introduced continuously by means of a metering pump. Then the suspension was allowed to react for a further 6 hours. Then 2.0 g of 3- (2,3-epoxypropoxy) propyltrimethoxysilane (Dynasylan GLYMO, Evonik) were added and allowed to cool slowly. The mixture was stirred overnight at room temperature and filtered the next day through a Buchner funnel. The pigment filter cake was dried at 120 ° C in a vacuum oven.

The resulting surface-modified effect pigment served as reference material for the subsequent powder coating applications.

Comparative Example 5:

Standart Spezial PCU 3500 (Eckart GmbH): commercially available stabilized aluminum pigment.

Comparative Example 6:

The starting material used is Standart Spezial PCU 3500, a commercially available stabilized aluminum pigment (from Eckart GmbH), corresponding to Example 1 of WO 2005/063897 A2 the further layer was applied by spray drying. However, instead of the standard used there special PCR 501 standard special PCU 3500 was used.

II. Application behavior of the powder coatings

The respective effect pigment was incorporated together with the highly weather-resistant powder coating 059/82170 shade black (from Tiger) and with 0.2% Acematt OK 412 (from Evonik) by means of ThermoMix for 4 minutes at stage 4. The pigmentation level was 5.0% by weight, since with higher pigmentation a verifiable application behavior can be achieved. As a result, the powder paint was weighed out to 95.0% by weight. The total amount of powder coating in the mixer was 300 g plus 0.6 g of Acematt OK 412. The ThermoMix is a commercially available kitchen mixer (Vorwerk). The additive Acematt OK 412 is SiO ₂ particles with a mean agglomerate particle size of 6.0 μm, which in this application assumes the function of a pouring agent. The powder coatings were applied with the OptiSelect (ITWGema) in a commercially available powder booth. In order to assess the application properties, spraying was carried out in the powder booth for 20 seconds according to the parameters given in Table 1, then the coating of the substrate was carried out and then the adhesions to the electrodes and to the impact plate were assessed. This method allows a conclusion on the long-term behavior of the pigments during the practice-oriented coating. Furthermore, the spray pattern was evaluated on the basis of the baked powder coating. The focus was mainly on the course, so the smoothness of the surface structure, and on black, microscopic flaws, so-called black spots thrown. Black spots are areas on the powder coating surface that are caused by an inhomogeneous distribution of the effect pigments. Since these phenomena are in the macroscopic range, the appearance is assessed paint technically trained look needed. In particular, very smooth structures with a very smooth course without the appearance of black spots are preferred. The application behavior, the presence of black spots and the structure or the course of the powder coatings were assessed visually.

At low application voltage (40 kV-10 μA), powder coatings containing effect pigments from the comparative examples had significantly stronger adhesions to the impact plate and electrode than powder coatings containing surface-modified effect pigments according to the examples according to the invention. In powder coatings containing effect pigments according to the comparative examples, markedly black spots were to be recognized after the application, whereas powder coatings containing surface-modified effect pigments from the examples according to the invention did not or only to a very small extent do so. Furthermore, the course of the powder coating and the structure of the appearance was positively influenced by the surface-modified effect pigments according to the inventive examples. Both the course and the structure were perceived much more uniformly by the viewer.

Particularly evident were the improved optical properties in the direct comparison of applications, which with powder coatings containing surface-modified effect pigments according to the inventive examples and applications, which with powder coatings containing the corresponding non-surface-modified effect pigment expressed. In Table 1, therefore, the respective letter in the column precursor refers to the same starting material, which was then surface-modified according to the inventive examples or was used according to the comparative examples.

At a higher application voltage of 100 kV-100 μA, almost all tested powder coatings comprising effect pigments as indicated showed good to very good application properties. However, the appearance of the baked powder paint on the sheet was very different. Powder coatings which contained surface-modified effect pigments according to the examples according to the invention had, in comparison with the corresponding powder coatings with effect pigments from the comparative examples, a significantly more uniform structure and a smoother course of the pigmented powder coating. Again, black spots were seen only in the applications of powder coatings containing effect pigments according to the comparative examples. For applications of powder coatings containing surface-modified effect pigments according to the examples of the invention. These did not occur.

Comparative Example 6 was one according to WO 2005/063897 A2 manufactured effect pigment. Such effect pigments produced can be applied very well in a powder coating application because of the same electrostatic properties of the powder coating particles and the effect pigment coated with the corresponding binder. In contrast to powder coating applications which contain the effect pigments to be used according to the invention, these powder coating applications are distinguished by their optical depth effect. An observer perceives a certain glittering effect over the entire viewing angle. A powder coating comprising effect pigments according to Comparative Example 6 therefore has an overall more lively effect than the powder coating containing a uniform appearance containing the surface-modified effect pigments to be used according to the invention. This difference can also be detected by light microscopic images. shows a light micrograph (light microscope Axio (lean Z1m, Zeiss) of the effect pigment of Comparative Example 5. shows a corresponding light micrograph of the effect pigment from Comparative Example 6 are the effect pigments unlike largely arranged plane-parallel to the ground. This is perceived by the human eye when looking at the corresponding powder coating application as a homogeneous appearance. Due to the rather statistical distribution of effect pigments in the corresponding powder coating application is seen by the human eye as alive and with depth effect.

III. Facade cleaning test

To assess the facade cleaning ability, a paint panel coated with the correspondingly pigmented powder coating was tested for resistance to abrasion by cleaning agents. To carry out a square tube (1 = 12 cm / B = 6 cm / H = 4 cm / weight 500 g) was once wrapped with a soft cloth. 2 ml of the cleaning solution Ambruch 2 Kunststoff Intensivreiniger (Rudolf Ambruch GmbH) were evenly distributed on the cloth. The paint panel with the coating to be tested was fixed on a table and the square tube moved back and forth without exerting any additional weight on the coating. Here, once back and forth corresponds to a cycle. After every 10 cycles, the detergent was removed with a dry cloth. This sequence was repeated until 30 cycles were reached.

To assess the paint panels were visually inspected for color and / or effect shift. Table 2 Example or comparative example Structure / History Effect loss after cleaning test Ambruch 2 30 cycles Req. gem. example 1 very uniform, no black spots, no pigment agglomerates light Req. gem. Example 2 uniform, no pigment agglomerates light Req. gem. Example 3 very uniform, no black spots, no pigment agglomerates light Comparative Example 1 Black spots, inconsistent, pigment agglomerates medium Comparative Example 3 Black spots, inconsistent, bad edge wrap strongly Comparative Example 4 uniform, black spots, isolated pigment agglomerates, insufficient coating of the substrate edges easy to medium

Powder coatings containing effect pigments from Comparative Examples 1, 3 and 4 had a medium to strong loss of effect. On the corresponding paint panels a very clear discoloration towards black was observed. The paint panels looked extremely uneven after the test and visually very unattractive.

Powder coatings containing surface-modified effect pigments according to the examples according to the invention also had an effect loss. This was less pronounced. There was only a slight discoloration towards black. The desired gloss effect (produced by the respective surface-modified effect pigment) was virtually retained. The paint panels appeared much more uniform to the viewer.

A possible explanation for this could be that the surface-modified effect pigments, because of the additional epoxide groups, are much better able to interact with the surrounding coating and form covalent bonds. The surface-modified effect pigments are thus better integrated into the powder coating matrix, which is reflected in an improved cleanability of the facade.

IV. Determination of the Specific Epoxy Equivalent Weight of the Surface-Modified Effect Pigments

The specific epoxide equivalent weight is understood to mean the amount of pigment in grams which contains 16 grams of epoxide oxygen (epoxide oxygen). The determination of the specific epoxide equivalent weight was carried out as follows:
Exactly 10 g of surface-modified effect pigment was weighed into an 80 ml beaker and concentrated in about 10 ml of chloroform and about 40 ml of conc. Stirred up acetic acid. Approximately 2.5 g of cetyltrimethylammonium bromide were added and dissolved with stirring, if necessary also heating. The sample was placed on the magnetic stirrer and the electrode immersed. The sample was titrated with 0.1 N acetic perchloric acid. The consumption thus determined is included as VB (1) in the calculation of the specific epoxide equivalent weight.

Since different occupied effect pigments enter into a neutralization reaction with the perchloric acid even without epoxide coating, it is necessary to call a so-called zero value or also amine number, to determine the respective starting pigments. The consumption VB (2) of Titrand for determining the zero value is then subtracted from the consumption VB (1) for determining the epoxide content.

To determine the zero value or amine number, exactly 10 g of non-surface-modified effect pigment were weighed into an 80 ml beaker and concentrated in about 10 ml of chloroform and about 40 ml of conc. Stirred up acetic acid. The sample was placed on the magnetic stirrer and the electrode immersed. The sample was titrated with 0.1 N acetic perchloric acid. The consumption thus obtained is included as VB (2) in the calculation of the specific epoxide equivalent weight.

N

= Normalität des Titrationsmittels

f

= Faktor des Titrationsmittels

The weight in grams of the respective pigment depends on the expected specific epoxide equivalent weight and is equal to the determination of the zero value. The respective weight can be shown below Table 3 are taken. Table 3 Expected specific epoxide equivalent weight Weighing in grams <1000 0.7 g 1000 to 10,000 4 g 10,000 to 100,000 10 g Evaluation:

N

= Normality of the titrant

f

= Factor of the titrant

V. Determination of the epoxide equivalent weight of the compound containing epoxide groups

N

= Normalität des Titrationsmittels

f

= Faktor des Titrationsmittels

By epoxide equivalent weight is meant the amount of pigment in grams containing 16 grams of epoxide oxygen (epoxide oxygen). The determination of the epoxide equivalent weight was carried out as follows:
Depending on the expected epoxide equivalent weight, the amounts of epoxide group-containing compound were weighed into an 80 ml beaker according to Table 3 and in about 10 ml of chloroform and about 40 ml of conc. Acetic acid dissolved. Approximately 2.5 g of cetyltrimethylammonium bromide were added and dissolved with stirring, if necessary also heating. The sample was placed on the magnetic stirrer and the electrode immersed. The sample was titrated with 0.1 N acetic perchloric acid.
Evaluation:

N

= Normality of the titrant

f

= Factor of the titrant

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1812518 B1 [0011]
• EP 1339806 B1 [0012, 0013]
• EP 1646693 B1 [0013]
• WO 2006/136435 A2 [0014, 0015, 0031, 0031, 0085]
• WO 2005/063897 A2 [0015, 0031, 0031, 0085, 0145, 0150]
• EP 0764191 B1 [0016]
• EP 2098574 A2 [0017]
• WO 98/46682 Al [0018]
• US 7618489 B2 [0019]
• EP 1980594 B1 [0042]
• EP 1682622 B1 [0125]

Cited non-patent literature

• Hans Pfeifer, Journal of Surface Technology 01/2003, S. 24-27 [0126]

Claims (16)

Use of surface-modified effect pigments in a solvent-free coating composition, characterized in that the surface-modified effect pigments have a platelet-shaped substrate and at least one dielectric layer, wherein at least one optional protective layer can be arranged on the at least one dielectric layer, and the effect pigments on the effect pigment surface have at least one epoxide group-containing Surface-modified compound, with the proviso that the at least one epoxide group-containing compound does not contain silicon atoms. Use according to claim 1, characterized in that the platelet-shaped substrate is a non-metallic platelet-shaped substrate and is preferably selected from the group consisting of natural mica, synthetic mica, glass flakes, SiO ₂ platelets, Al ₂ O ₃ platelets and mixtures thereof , Use according to claim 1, characterized in that the platelet-shaped substrate is a metallic substrate and the metal of the metallic substrate is preferably selected from the group consisting of aluminum, copper, zinc, iron, stainless steel, their alloys and mixtures thereof. Use according to any one of the preceding claims, characterized in that the at least one dielectric layer is selected from the group consisting of metal oxides, metal oxide hydrates, metal hydroxides, organic dielectric materials and mixtures thereof. Use according to any one of the preceding claims, characterized in that it comprises at least one optional protective layer of metal oxides and / or metal hydroxides of aluminum, cerium, chromium, silicon, zirconium and / or mixtures thereof. Use according to one of the preceding claims, characterized in that the at least one optional protective layer comprises metal oxides and / or metal hydroxides of silicon and / or acrylates and / or mixtures thereof. Use according to one of the preceding claims, characterized in that the at least one epoxide group-containing compound has at least two epoxide groups. Use according to one of the preceding claims, characterized in that the proportion of the at least one epoxide group-containing compound in a range of 0.5 to 8 wt .-%, based on the total weight of the surface-modified effect pigment is. Use according to one of the preceding claims, characterized in that the surface-modified effect pigments have an average diameter D ₅₀ from a range of 2 to 100 μm. Use according to any one of the preceding claims, characterized in that the surface-modified effect pigments have a specific epoxide equivalent weight in the range from 119,000 to 800, based on the total weight of the surface-modified effect pigment. Use according to one of the preceding claims, characterized in that the solvent-free coating agent is a powder coating or toner. Surface-modified effect pigments comprising platelet-shaped substrates with at least one dielectric layer, it being possible for at least one optional protective layer to be arranged on the at least one dielectric layer, characterized in that the effect pigments are present on the effect pigment surface with at least one epoxide group-containing compound are surface-modified, with the proviso that the at least one epoxide group-containing compound contains no silicon atoms, and the surface-modified effect pigments have a specific epoxide equivalent weight from a range of 119000 to 800, based on the total weight of the surface-modified effect pigments. Solvent-free coating composition comprising surface-modified effect pigments, characterized in that the surface-modified effect pigments have a platelet-shaped substrate and at least one dielectric layer, wherein at least one optional protective layer can be arranged on the at least one dielectric layer, and the effect pigments are surface-modified on the effect pigment surface with at least one compound containing epoxide groups with the proviso that the at least one epoxide group-containing compound contains no silicon atoms. Solvent-free coating composition according to claim 13, characterized in that the surface-modified effect pigments have a specific epoxide equivalent weight from a range of 119,000 to 800, based on the total weight of the surface-modified effect pigments. Solvent-free coating composition according to claim 13 or 14, characterized in that the solvent-free coating agent is a powder coating or a toner. Coated article, characterized in that the article is coated with a solvent-free coating agent according to any one of claims 13 to 15.

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