MXPA96001660A - Preparation of pigme - Google Patents

Abstract

A pigment preparation is described comprising: (i) from 10 to 80% by mass of a support material in the form of plates, coated with an oxide, and (ii) from 20 to 60% by mass of an active pigment. The support material coated with metal oxide is preferably a mica coated with titanium dioxide or iron oxide. The active pigment is preferably zinc phosphate, zinc borate, calcium metaphosphate, phthalocyanine or a material that binds hydroxide ions, such as silica gel, silicate, aluminosilicate, calcite, metaphosphate or bi- or triphosphate.

Description

PREPARATION OF PIGMENT DESCRIPTION OF THE INVENTION The present invention relates to pigment preparations that are free of lead compounds, chromate compounds and toxic organic compounds, and are intended for the formulation of coating materials, especially corrosion-resistant coating materials. In the protection of metallic articles against corrosion by means of organic coatings, the dresser is, as is well known, of particular importance. Its main function is to ensure the perfect and energetically stable adhesion on the metal substrate, especially under the action of wet or water atmospheres. In addition, its permeability to water and oxygen must be minimal, and finally it must be highly suitable as a substrate for subsequent coatings. Since the development of the adhesive bond with the metal surface to be protected, and the binding reactions of the primer with a subsequently applied organic coating, can be regulated mainly by the choice of the so-called film former (organic linker) in cooperation with auxiliary formers of film, suitable (for example, catalysts for the crosslinking of the polymeric film), the permeation properties of the coatings are also substantially affected by the introduction of pigments. It is particularly advantageous to use typical barrier pigments, whose overall or plate structure means that they are so favorably incorporated into the organic coating, that they result in a significant enlargement of the diffusion pathways and, consequently, an acute reduction in permeability . A precondition for the optimal expression of this effect is, of course, that the pigment / linker interactions are sufficiently stable to water. Good anti-corrosion primers contain not only barrier pigments but also active pigments, which are not intended to show their action until local coating effects have formed on the coating through the metal substrate. Before this, they also go to contribute to the barrier effect, or they must at least not reduce the effect caused by the barrier pigments. The manner in which and the degree to which an active pigment reacts in such local defects in the case of the penetration of corrosive aqueous media, and can ultimately cause a "cure" of the defect, naturally depends on a large number of parameters. Examples include the size of the defect, the nature of the pigment, the volume composition of the pigment (c.v.p.) and the composition of the corrosive medium that has penetrated into the defect. In zinc-rich planters, for example, zinc particles act as a sacrificial anode. In addition, relatively insoluble corrosion products are produced, zinc, which are deposited as solid compounds in the defects of the coatings on the steels and plug these defects. Red lead and zinc chromate, on the other hand, are strong oxidizing agents and have a passivating effect on metal surfaces exposed within the coatings in the presence of water. The reaction products, finally, lead to the formation of relatively insoluble compounds (metallic soaps) which plug the defects in the organic coatings and, in addition, chemically bond with the corrosion-promoting ions, of the adjacent aqueous media (eg sulfate and chloride example).

The use of zinc rich planters is associated with various disadvantages. This requires an extremely high pigment volume concentration, in terms of zinc, which is very expensive. In addition, the action of zinc as a sacrificial anode is guaranteed only at the normal temperature with respect to certain ferrous materials. In warmer waters (greater or equal to 60 ° C), the potential is reversed, thus resulting in more severe corrosion, as a consequence of the local element formation, of the steel substrate exposed in the defects of a coating. A further disadvantage is that the zinc particles themselves have a tendency to corrosion if the coating has absorbed moisture. The gaseous hydrogen that is produced in this case can destroy the coating mechanically and by this means can even promote the progressive penetration of the corrosive media downwardly towards the metal substrate to be protected. The use of lead compounds and chromate compounds as pigments in coating materials is no longer allowed, as these are classified as toxic and carcinogenic. Among the alternative active pigments proposed to date, the list has been headed by various zinc solids of relatively low solubility, such as zinc phosphate, zinc borate or zinc gluconate. Zinc phosphate in particular is being applied to an increasing degree. This can not, of course, exert any electrochemical effect. As already stated, the activity in zinc phosphate pigments in anti-corrosion primers is based mainly on the fact that it converts corrosion products from ferrous substrates, whose products are initially formed under the action of an aggressive aqueous medium in the defects of the organic coating, in virtually insoluble compounds, solids, for example, in basic phosphates of Fe (I?) -zinc, which in turn leads to plugging or sealing of the defects. Contrary to the aforementioned active pigments, therefore, the action of zinc phosphate is directed to the preceding corrosion of the metal substrate to be protected, at the defect sites of the organic coating in the porous base. As expected, therefore, the anti-corrosion effect of zinc phosphate is usually much lower than that of zinc chromate or red lead and, in addition, is highly dependent on the composition of the aqueous medium in the defect. The same applies in principle to all other active pigments whose mechanism of action, like that of zinc phosphate, consists in the reactive transformation of the primary products of the corrosion of the relevant metallic substrate, with the formation of solid salts or compounds complexes, in local defects of an organic coating, examples being zinc borate or zinc gluconate. In order to compensate for this disadvantage it has been proposed to formulate the pigment volume concentration of such active pigments, at levels much higher than was the case for zinc chromate with the previous coating formulations, and, in addition, to employ particularly finely dispersed pigment powders, in order to achieve uniform distribution within the coating (U.S. Patent No. 4,243,707). However, since the pigments involved are to a limited degree soluble in water, and this tendency to dissolve is markedly increased when there is an acute reduction in the particle size, the coatings formulated with these, as their concentration in volume is increased. pigment, show an increasing tendency towards osmotically stimulated swelling. This in turn results in a relatively rapid delamination of the coating from the metal substrate over a large area, with the consequence of reduced anticorrosion properties (Progr. In Org. Coatings _1_8 (1990) 123). In the case of pigments such as zinc phosphate and zinc borate, an additional factor is that these may contain different amounts of water of hydration. In order to prepare them in finely dispersed form, they must be dried more intensively, and may then contain only a minor amount of water of hydration. The zinc phosphate pigment, for example, is then in the form of the dihydrate, Zn (PO),) ~ • H ~ 0. When coatings pigmented with this pigment are exposed to water, there is an affinity for the conversion to the tetrahydrate, which likewise promotes swelling of the coating and reduces its anti-corrosion properties. Similar effects are also known for zinc borates. Effects of this type, of course, occur mostly the higher the concentration in volume chosen, of such pigments. In order to limit these effects sufficiently, the starting point for other proposals is to formulate the pigment volume concentration of such pigments only at about the level that was customary for zinc chromate in the previous coating formulations, but employing these pigments in a form in which these are surface modified with a second substrate, or contain said substance as an additional component. Although the surface modification of the pigments having a low proportion of water of hydration with organic or inorganic coatings, is able to oppose the aforementioned incorporation of additional water of hydration, this does not necessarily lead to an improvement in the activity of the pigment. Methods that have proven to be better than this include combinations of an active pigment with an additional solid component, which supports the conversion process of the primary corrosion products, into a virtually insoluble compound, for example by establishing a favorable pH in the defect of the organic coating. Mention may be made here, by way of example, of zinc phosphate / zinc borate combinations (US Patent No. 3,829,395), zinc phosphate / zinc molybdate, zinc phosphate / zinc oxide, zinc phosphate / aluminum phosphate. (or polyphosphate) and barium metaborate / zinc oxide. To improve the action of phosphate, DD 245 892 proposes the incorporation in the coating material of 8 to 16% of a mixture comprising 30 to 70% of natural calcite and 70 to 30% of synthetic calcium carbonate, and that in this way it is intended to ensure that in the defects of the coating on the steel, if the water penetrates, the pH is favorable for the formation of phosphate of Zn-Fe and basic carbonates. The anti-corrosion properties of the precursors that are achieved with such pigment combinations, however, are less than with the use of the classic active pigments of red lead or zinc chromate, especially in the case of exposure in media that They contain clolide. In addition, the use of calcium carbonate entails the risk that the swelling capacity of the coatings will be increased. Finally, the hydrolysis of this filler can result in the aqueous medium within the coating adopting a pH of about 12, whereby its desadhesion (delamination) is promoted, and the anti-corrosion effect is relatively lost. fast For the formulation of water-dilutable polymer dispersions, as anti-corrosion primer coating materials, as compared to solvent-containing binders or binders, it should be further taken into account that the water-soluble solubility pigments may deteriorate the stability of the dispersion. Above certain specific ionic concentrations of the system, in fact, coagulation may occur in the container, rendering the coating material unusable. Similar effects should be expected if the pigments force a change in the pH of the polymer dispersion. The action of active pigments, which like phosphates, borates, molybdates, gluconates, etc., point to the conversion of primary corrosion products into solid compounds that plug or plug the defects of a coating organic, intensifies, as expected, when these are combined with an oxidizing agent. Sufficiently strong oxidizing agents, such as red lead or chromates, subsequently passivate the metallic substrate that is exposed to the defects of an organic coating, so that the additional pigment, such as phosphate, borate or molybdate, has only that convert the Fe (III) ions, which are produced in small quantities in the case of passive steel substrates. Since lead compounds and chromate compounds can no longer be applied, it has been proposed to employ zinc phosphates or zinc borates in combination with organic nitro compounds, especially their relatively insoluble zinc salts. Products of this type are still used in commerce today (SICORINE; BASF). These nitro compounds are weaker oxidizing agents than, for example, the chromates, and accelerate the corrosion of the exposed metallic substrate in the pores of a coating, for example in accordance with Fe - * Fe2 + + 2e ~ and, whereby these are by themselves reduced, for example in accordance with: R-N02 + 2H + 2e - * R-NO + H20 By this means it is certain that the products of the corrosion of the metal substrate to be protected are relatively quickly and sufficiently available for the formation of solid compounds which plug the defects of an organic coating, and it is on this phenomenon that it appears to be based on the relatively good anti-corrosion effect of the zinc phosphate or zinc borate pigments, mobilized in this way. Under the strictest environmental legislation of today, however, these nitro-organic compounds and probably to a greater degree the resulting reduction products (nitrous compounds) must be classified as toxicologically objectionable, so that the active modified pigments of this can not be accepted as a true alternative for the substitution of toxic chromates. The German Patent Application No. P 44 11 568. 7 describes a pigment preparation for anti-corrosion coating materials, which comprises a material in the form of plates and a material that binds hydroxide ions. This pigment preparation can also comprise a conductive pigment in the form of plates. Protective coatings on ferrous materials that are produced with the pigment preparation provide better protection against corrosion than protective coatings comprising chromate pigments. Given the choice of an appropriate binder or linker, these protective coatings can also be used for other metals that corrode, for effective protection against corrosion, under atmospheric exposure and in aerated aqueous media. The pigment preparation is not, however, suitable for waterborne coating materials. There is therefore a need for pigment combinations that are free of lead compounds, chromate compounds and toxic organic compounds, and which when used in coating primers on metals susceptible to corrosion, show an anti-corrosion effect that at least equals that of the lead and chromate pigments. The object of the invention is to provide a pigment preparation that can be incorporated into either coating formulations based on customary binders or binders and within coating materials that carry water and, as a primer on a very wide variety of substrates metallic, especially on surfaces of ferrous materials, which possess anti-corrosion properties which are compatible with the protective effect of pigments containing lead and containing chromate. This pigment preparation must have pronounced anti-corrosion properties, not only under atmospheric exposure but also in aerated aqueous media. This objective is achieved, in accordance with the present invention, by a pigment preparation comprising: (i) from 10 to 80% by mass, preferably from 30- (by mass, of a support material in the form of plates of high electrical resistance and pronounced chemical resistance, which is coated with a metal oxide, and (ii) from 20 to 90% by mass, preferably from 40 to 80% by mass, of an active pigment.

The term "metal oxide coated plate carrier material" includes mixtures of support materials coated with different metal oxides. The support materials in the form of plates, used, are natural or synthetic mica and other phyllosilicates, such as talc, kaolin, sericite or even glass plates. Preferred plate-shaped support materials are mica and plate-shaped pigment prepared according to the international application NB PCT / EP92 / 02 351. These consist of a matrix in the form of plates, inorganic, transparent, preferably dioxide of silicon. The matrix is produced by the solidification of a liquid precursor on a continuous band. Additional constituents can also be incorporated into this matrix. The insert-shaped support materials typically have a thickness between 0.05 and 5 microns and >; in particular, between 0.2 and 2 microns. Its extension in the other two dimensions is between 1 and 250 microns and, in particular, between 5 and 60 microns. The proportion of the extension in the main dimension to the thickness (aspect ratio) is greater than 3 and preferably greater than 5. The support materials in the form of plates can be coated with Ti02, Fe ^ O-, Cr20 ~, Zr02, Si02, A1203 and ZnO. The metal oxide layers are preferably applied by a wet chemical method, in which context it is possible to use the wet chemical coating method developed for the preparation of pearlescent luster pigments; such methods are described, for example in the documents Nos. DE 14 67 468, DE 19 59 988, DE 20 09 566, DE 22 14 545, DE 22 15 191, DE 22 44 298, DE 23 13 331, DE 25 22 572, of 31 37 808, DE 31 37 809, DE 31 51 343, DE 31 51 354, DE 31 51 355, DE 32 11 602, DE 32 35 017 or even additional patent documents and other publications. Suitable metal oxide-coated plate-shaped support materials are mica-based pearlescent pigments which are commercially available under the designation "Iriodin" (product of E. Merck, Darmstadt). The oxide cover which adheres firmly to the chemically inert support material in the form of plates, preferably micas, is resistant to contact with aqueous media in the range of 2 < pH < 12 and forms only amphoteric surface hydroxyl groups, which are characterized by an isoelectric point p vHi.so < 5. Pigment particles of this type can be suspended well and uniformly in organic binders comprising polymers having appropriate functional groups, such as carboxyl and C-C alkenyl double bonds. In this context, they enter into acid-base interactions with the binder polymers, a consequence of which is the development of a preferential orientation of the solid constituents within the fluid mixed phase. This has a beneficial effect on the uniformity of the distribution of the additional pigments and additives in the coating material, and becomes much more intense as, during the formation of the film on the substrates, the solvent evaporates from the coating initially still wet. The preferential orientation of the polymer-containing particles within the organic film formers which is originated, in accordance with the invention, by the solid pigments covered with oxides creates at the end particularly advantageous conditions for the uniform adhesion, of intense energy, of the coatings produced with these on the metal substrates, and for the crosslinking of the functional polymers of the binder with one another to form a cohesive coating of extremely low structural porosity, giving rise entirely to coatings with a remarkably high barrier effect. The specific electric resistance R "p (S * cm) of the support material in the form of plates, coated with a metal oxide, must be greater than or equal to 10 (S · cm) at 25 ° C. The values measured on compressed powder mounds, using the capacitor discharge method and the four-point method at 25 ° C gave for Iriodin 9504 (pearl luster pigment, manufacturer: E. Merck) an average of 2.3x10 IL- cm and for Iriodin 9103 an average of 5.5x 10? • cm. The term "active pigment" refers to compounds that are capable of converting the primary corrosion products, which are formed into the defects of an organic coating, into a stable compound in water, solid and, in doing so, ensures that the defects are plugged or sealed, while the anti-corrosion properties of the coating are retained. Examples of this type of active pigment are zinc phosphate, zinc borate and calcium metaphosphate. The term "active pigment" further refers to monomeric and / or polymeric, metal-free or metal-containing chelate complex compounds, according to the general formulas I and II: wherein A and B each independently of the other are an aromatic or cycloaliphatic radical, which may also contain heteroatoms, such as sulfur, selenium, oxygen and nitrogen, and aryl, alkyl, halogen, oxygen-containing, sulfur-containing groups or containing nitrogen, as additional substituents, R3 and R4 are hydrogen atoms alkyl radicals, I am iron, nickel, cobalt, manganese, bismuth, tin, zinc or H2, these complex chelate compounds exert a passivating effect on the metal surface. As complex chelate compounds it is preferred to employ phthalocyanines, tetraarylporphyrins and tetraazaanulenes. Among the phthalocyanines, metal phthalocyanines and, in particular, phthalocyanine iron are preferred. The problem of the higher preparation costs involved by the metal phthalocyanine, can be counteracted by the use of this active component for conductive support materials, such as surface modified mica and / or graphite, and thus the desired objective is achieved with much less of the effective active substance, metal phthalocyanine, with an equal or even greater anti-corrosion effect. The term "active pigment" also refers, according to the invention, to materials that bind hydroxide ions, examples being metaphosphates, bi-and triphosphates, silica gels, silicates, alumino-silicates, calcite and all salts Relatively insoluble metals, which form relatively insoluble basic salts or complex compounds with OH ions. For example Ca [Si0"] collects the hydroxide ions to form Ca" (OH) [Si, 0.]. It is also possible to use those compounds which, on their surface, form a buffer system which fixes the pH of the adjacent aqueous medium in the range of 6 < pH 8.5, which is considered as non-harmful for the delamination of organic coatings on steel substrates: R-C00 ~ + H20 «* R-C00H + 0H ~ Preference is given to the use of calcium metaphosphate, which binds the hydroxide ions that are formed during the reduction of oxygen. According to the invention, it is also possible to use mixtures of the active pigments described above. The preparation of the pigment according to the invention is produced from individual components using the machinery and methods which are customary in the pigment and coating industry, and dispersed in coating formulations based on customary binders. It is also possible, however, for the individual components in succession, to be dispersed in the binder. For the incorporation of the pigments in the form of plates, covered with oxide, the methods to be used should not lead to the destruction of these particles, for example to their breaking by grinding. It has been found appropriate to select these pigments in the form of oxide-coated inserts, in a fraction of particle size which is favorable for the consistency of the coating material involved, and then to incorporate the pigments into the coating material by means of dispersants. The binders used are alkyd resins, polyurethanes, chlorinated rubber or melamine resins, which are present in the coating formulations in an amount of from 35 to 55% by mass. The selection of binders requires carrying out optimization studies, although this is customary in the art. It is necessary to ensure that a sufficient quantity of the oxygen dissolved in the electrolyte of the defect of a coating is reduced, in the so-called 4-electron passage, to form OH ions and to "dampen" against these OH ions that are formed. If only a relatively small amount of dissolved oxygen is available and this is reduced only according to a two-electron step, for example according to: 02 + 2H + 2e H2 ° 2 then it does not act as a passivator but merely promotes the discontinuity or anodic breakdown of the metallic substrate. An excess concentration of inert substances, for example the auxiliaries required in the specific system, can also be an impediment, since this counteracts adequate subsequent supply of oxygen (incipient diffusion), or the amount of locally available Ca-MP, is too little to dampen the OH ions. The concomitant effect of dissolved oxygen as a passivator is necessary in practice with all the indicated effects, when the intention is for the aforementioned activity to take place in defects of the relevant coating. This also applies mainly to coatings pigmented with zinc phosphate or zinc borate, although in that case a "plugging or clogging process" may also be present as a result of various precipitation reactions. Pigment preparations according to the invention, which contain a catalyst, for example phthalocyanine iron, have the advantage that the above-mentioned four-electron pass catalysis, even in the presence of relatively little dissolved oxygen, ensures reliable passivation of the metallic surface. The aforementioned additives and substances that are required for the specific system must not in any way always be mixed with a coating formulation, but are only used if they improve the useful properties and the processing properties of the coating material. Examples of the additives and substances required for the specific systems are inert substances such as fixed white, talc or mica. However, although these are not active pigments per se, even if they are of natural origin, as a result of their dispersion interactions with the other pigments, they ensure the fine dispersion of these pigments and counteract the agglomeration. The pigment preparation according to the invention is present in the coating materials in concentrations from 10 to 45% by mass. The pigment preparation according to the invention is produced from the individual components, using machines that are customary in the pigment and coating industry, such as sand mills or ball mills, ball mills and mills. roll, in which they are ground to a fineness that corresponds to what is usual in practice, and are dispersed in coating formulations based on customary binders. It is also possible, however, for the individual components in succession, to be dispersed in the binder. Such binders are alkyd resins, polyurethanes, chlorinated rubber or melamine resins, which are present in the coating formulations in an amount from 35 to 55% by mass. The additional constituents, in an amount of up to 2% by mass, are drying and auxiliary, for example dispersants, release agents, anti-settling agents, adhesives or thixotropic agents. Solvents are also present, in a proportion of 10 to 20% by mass, which must be matched - in a manner customary in the art - to the respective binder. The customary solvents are butyl acetate, xylene and mixtures of paraffinic hydrocarbons in the boiling range of 120 to 180 ° C. Since the functional groups with affinity for water of the polymers of the organic binders involved are linked, as a result of the acid-base interactions, with the solid pigment particles coated with oxide, present according to the invention, and the crosslinking reactions that are promoted as a result, to a much greater extent than in the coating quantities that do not contain the additive according to the invention, the films produced with these have a tendency - >; much smaller when, in the cured state, they are brought into contact with aqueous media, to absorb water (swelling) and to allow their diffusion or permeation down the metallic substrate. Finally, this is true even if the coating material comprises active pigments with affinity for water, such as zinc phosphate, zinc borate or calcium metaphosphate, for example. The addition according to the invention of a solid pigment covered with oxide, in fact, ensures that such active pigments are embedded within the coating in uniform and fine distribution, and not in agglomerates of size-adjustable particles, without any loss in their activity. This activity is in fact promoted, since the organic coatings comprising an addition according to the invention are, on the other hand, more slowly packed and, on the other hand, have a greater adhesion strength to the metal substrate. This ensures that the breaking or discontinuity reactions that occur in such a film under the influence of aggressive aqueous media, lead only to defects of relatively small dimension, from which the active pigment is not washed. Finally, if the local breakage of the film has advanced down the metallic substrate, the persistent high adhesion strength of the coating in the adjacent regions prevents the initiation of corrosion under the film (in the case of ferrous materials: sub-moldy). Corrosion of the exposed metal substrate over a relatively small area in the porous base of such a defect can, under these conditions, be apparently effectively and rapidly inhibited by the active pigment present in the electrolyte-filled defect, as evidenced by the results of the corrosion tests carried out accordingly. In this case there is no need for the concomitant effect of an oxidizing agent, which promotes the formation of a solid compound in the defect of the organic coating, either by stimulating the corrosion of the exposed metal substrate or by mediating its passivation. The simultaneous existence of such an effect, however, is not in any way harmful to the anti-corrosion effect that can be achieved. If the pigment preparation according to the invention contains as active pigment a quelatq-forming compound and a material that binds hydroxyl ions, according to German Patent Application No. 44 11 568.7, by means of which the atmospheric oxygen that is present in the aqueous medium of the defective organic coating is enabled to passivate the metal substrate that is exposed in the porous base, then these sites "heal" particularly quickly and the anti-corrosion properties of the coating remain completely safeguarded after this. It has already been emphasized that the activity of the pigments in the form of oxide-coated plates used according to the invention in anti-corrosion primers is mainly attributable to the acid-base properties of the surface hydroxyl groups present on the surface. the oxide coating, whose action is documented in the isoelectric points pHi.so < 5. The basis for this is the so-called hard-soft principle (HSAP) which goes back to Pearson (see for example: Acid-Base Interactions: Relevance to Adhesion Science an (l Technology (Edited by KL Mittal and HR Anderson, junior ), VSP Utrecht, The Netherlands 1991, 25 pages), according to which strong Lewis acids, for example the functional groups -MeOH ^ which are present above the oxide surfaces below pH., Preferably enter into interactions with the strong bases of Lewis, for example the polymeric particles that contain carboxyl functional group of an organic binder The Lewis weak acids, on the other hand, interact mainly with the weak bases of Lewis, an example of whose interaction is the adsorption of particles of resin containing vinyl groups, via the CC double bond of the alkenyl (TG electron system "as weak base) on the oxide-free surfaces of the transition metals ( weak) acid affinity for AR (= -.? ~ G °) of the first interactions, the relationship has already been theoretically supported (at 25 ° C: AR = 5.7 (pK.-pH.) in Kj / mol) (see, for example: Interface Conversion for Polymer Coatings (Edited by P. Weiss and GD Cheever) Elsevier Ltd. New York 1968, pages 3-60). Consequently, AR is larger the greater the difference between the isoelectric point of the oxide, pHi.so, and the negative decimal logarithm of the dissociation constant K, of the relevant base (value of pK,). The pigments used according to the invention having the trade name Iriodin 103 or 9103 WR consisting of 42% titanium dioxide (rutile) on mica, have prHi.so = (4.7 ± 0.2), while those designated Iriodin 504 or 9504 WR, which consist of 46% ferric oxide (Fe20-) (hematite) on mica, have p ^ H i .so = (3.6 ± 0.2). Consequently, due to pH I.SO < 5, these bring about substantially better preconditions for energy-intensive interactions with strong Lewis bases, for example polymeric particles containing carboxyl functional group, than in the relevant oxide powders. However, the pH. (isoelectric point, foot, approximately identical with the point of zero charge, pcc) in the case of titanium oxide Ti0"(rutile) is always 5.8, and in the case of oxides of Fe (III) is even _5_ 6.5 (see, for example: Chem. Rev. 65 (1965) page 177 ff., and Progr. in Org. Coatings 19 (1991) page 227 ff.). In the coatings produced with the coating materials whose pigment combination comprised ferric oxide powder (Fe20o) (for example Bayferrox red iron oxide 140) and / or titanium dioxide powder (Ti0") (white pigment) in addition to a active pigment such as zinc phosphate or zinc borate, the effect according to the invention did not occur, and the anti-corrosion properties found were in each case poorer than those achieved with the pigmentation using red lead or zinc chromate. The ferric oxide (Fe20"deposited on the support material in the form of plates, such as mica, in a manner contrary to oxide powders containing Fe (III) ions) is not electrochemically reducible. operate cathodically, for example with Fe203 + H20 + 2H t 2e 2Fe (0H) and cause corrosion in the Fe metal, for example in accordance with Fe + 2H2Q -? 2Fe (0H) + 2H + + 2e ~, giving the total reaction Fe + Fe203 + 3H20 3Fe (0H) which has actually been shown to take place. In the present lies an additional advantage of the application, in accordance with the invention, of the pigments in the form of oxide-coated plates, in the anti-corrosion primers. The improvement in the anti-corrosion properties of the active pigment containing precursors, which can be achieved with the pigments in the form of oxide-coated plates, especially on surfaces of ferrous materials, is in no way limited only to their use in non-aqueous coating materials, which are formulated on the basis of organic solvents, but are also properly obtained in waterborne coating materials, especially since these pigments have complete chemical resistance in the range of pH 4.0 < pH < 9.0 which is typical of waterborne coating materials. Accordingly, using the pigment preparations according to the invention, the anti-corrosion properties of the coating materials are also considerably improved, which have been formulated with polymer dispersions dilutable in water, especially when used for ferrous materials. The pigment preparations according to the invention are used for coating formulations which are applied as a primer to a wide variety of metal substrates, especially to ferrous materials. Once the formation of the film is complete, the aprestador is distinguished under atmospheric exposure or exposure to aerated aqueous media, for the anti-corrosion properties. The pigment preparations according to the present invention meet all the requirements that are imposed on the pigments for anticorrosive fasteners. They also do not damage the leveling of the film-forming properties of the coating material and, instead, lead to uniform coatings which have a high barrier effect, resist aging and adhere particularly firmly to metal substrates. Furthermore, they do not restrict the coating capacity of the resulting finisher for the construction of multiple coating systems and, in particular, are capable of counteracting the diffusion and permeation of the aqueous media within the organic coating, and of protecting the substrate. metallic against corrosion in the pores or defects of the coating, by causing rapid deposition of relatively insoluble compounds, and thereby plugging or plugging the defect sites. This also ensures that corrosion below the film does not occur, and that the anti-corrosion properties of the entire organic coating are maintained. A further advantage of the pigment preparations according to the invention is that they can be used in coating formulations based on polymer dispersions dilutable in water as well, without jeopardizing the stability of these waterborne coating systems. The pigment preparations according to the invention were incorporated in various binder systems, the particle size being less than 20 microns. By means of suitable diluents for the respective binder, and in the case of the water-borne coating material by the addition also of thickener, the coating materials containing the pigment preparations according to the invention received the processing viscosity. necessary In this way, five coating materials were prepared and used to coat metal sample panels consisting of steel produced in large quantities after complete pretreatment of the surface (mechanical polishing, degreasing with aqueous / organic cleaning agent, rinsing, These sample panels with comparable film thicknesses (60 ± 5 microns) were subjected to the following tests, during which they were compared in each case with a commercially customary reference system, including a coating containing zinc chromate: a) Exposure to the weather in accordance with DIN 53166 b) MACHU test, alternate exposure after 8 hours of immersion in a solution comprising 50 g of sodium chloride, 10 ml of glacial acetic acid and 5 g of 30% hydrogen peroxide solution per liter of water (fresh daily ) at 40 ° C and 16 hours of exposure in dry air at room temperature per cycle. c) Alternating weather test according to VDA [German Association of Automobile Manufacturers] 621-415.

Results of anti-corrosion tests a) Exposure to the weather in accordance with DIN 53166 After a period of outdoor storage, of 12 months, the slit that was made is surrounded, in the case of the samples covered by reference systems I, II and III, to a degree of 2 to 3 millimeters in width, by numerous small bubbles or blisters, while with the coatings of Examples 1 and 2, which comprise the pigment preparations according to the invention, only a few small blisters or bubbles have appeared isolated in the direct vicinity of the slit . On the samples with the pigment combination of Example 3 according to the invention, no formation of bubbles or blisters can be observed after 12 months. In the case of the samples coated with a coating system carrying water, the exposure to the weather was completed after 6 months as the reference system IV not only showed distinctive blistering but also had a number of penetration sites of moldiness. The evaluation of the degree of formation of blisters or bubbles of the coating according to DIN 53209 and of the corroded area provided, based on the total area after the release of the coating, gave the following average results: Coating Formation of Area proportion blisters corroded in% Reference System IV m 4 // g4 approximately 75 Example 4 m 1 // g! approximately 20 Test MACHU In the case of coatings produced with a solvent-containing coating material, the samples were evaluated after exposure for 8 cycles. The parameters determined were, again, the degree of formation of blisters or bubbles of the coatings in accordance with DIN 53209 and the corroded area provided, based on the entire area of the metal sample panels, after the release of the coating Coating Formation of area proportion ampoules corroded in% Reference system I m 3 /, g3 42 Reference system II m 4 /, g4 60 Reference system III 3, 3, p > / g 38 Example 1 m 1 // g approximately 5 Example 2 m 1 // g1 approximately 8 Example 3 0/0 < 1 The coatings produced with a coating material that carries water were evaluated only after 3 cycles: Coating Formation of area proportion ampoules corroded in% Reference system IV m V g 4 approximately 60 Example 4 m! / G approximately 10 Alternate climate test according to VDA 621 - 415 After 9 cycles of alternating climate exposure, the reference systems I, II and III show sub-molding in the slit, which at some points has progressed up to 3 mm, while coated Examples 1, 2 and 3 according to the process of this invention they can not be clearly evaluated at this stage (<1 mm). The samples coated with a coating material carrying water were evaluated after 6 cycles. In this evaluation, it was found that the coatings of the reference system IV have not only sub-milling in the groove, which had progressed to about 4 mm, but also initial corrosion penetrations in the form of broken lines. With the coatings prepared according to Example 4, the sub-molding that extends from the slit was minimal (<; 1 mm), but the degree of bubble formation or blistering of the coatings was rated on average as m2 / g. The results show that the protective coatings produced on the surfaces of ferrous materials with the pigment preparations according to the invention, in comparison to the reference system, they give rise to a markedly better protection against corrosion, despite the fact that the reference system II contains a highly effective chromate pigment. The full description of all applications, patents and publications mentioned above and below is included in this application by reference. The following examples are intended to illustrate the invention in more detail, but without limiting it.

Example 1% mass Zinc phosphate 7.41 Zinc white (zinc oxide) 11.97 Iriodin® 9504 WR 10.82 Microtalc N 6.38 Fixed white 6.37 60% resin solution in xylene (alkyd resin with short drying oil by air and heat drying) 42.85 Solvent 12.9 Driers and Auxiliary 1.3 Example 2 in mass Zinc Borate 11.22 IriodinR 9103 WR 16.6 Microtalc N 6.32 Fixed white 5.28 Plexigum resin solution PM 685 (acrylic resin in xylene) 42.72 Solvent 16.45 Driers and auxiliaries 1.51 Example 3 in mass Phthalocyanine iron 6.45 Calcium metaphosphate 12.8 Zinc phosphate 7.22 IriodinR 9504 WR 9.9 Resin solution as in Example 1 47.6 Solvent 14.6 Driers and auxiliaries 1.43 E emplo 4% en mass Zinc Phosphate 7.24 IriodinR 9504 WR 10.5 Microtalc AT extra 6.37 Micro fixed white 6.1 Zinc white 7.44 Water dispersible polymer dispersion, as a binder, consisting of a styrene-butadiene copolymer containing finely dispersed carboxyl functional group, with anionic emulsifier, 50% solids content, pH 8.5 52.7 Corrosion inhibitor containing nitrite. 2.5 Butylglycol 2.5 Antifoam, wetting agent, thickener 4.65 Comparative Example 1 in mass Zinc phosphate 7.20 Zinc white (oxide) 11.63 Microtalc N 6.19 Bayferrox 140 (red iron oxide) 13.36 Fixed white 6.19 Resin solution as in Example 1 41.64 Solvent 12.50 Driers and auxiliaries 1.29 Comparative Example 2 in mass Zinc yellow (zinc chromate) 7.63 Zinc white 11.63 Microtalc AT 1 6.19 Bayferrox 140 13.36 Fixed white 6.19 Resin solution as in Example 1 41.21 Solvent 12.50 Secant and auxiliaries 1.29 Comparative Example 3% by mass Zinc Borate 12.2 Microtalc N 6.7 Bayferrox 140 12.5 Fixed white 7.7 Resin solution as in Example 2 42.8 Solvent 16.5 Secant and auxiliary 1.6 Comparative Example 4 in mass Zinc Phosphate 7.0 Microtalc AT extra 6.0 Bayferrox 140 8.0 ' Fixed white 12.0 Polymer dispersion dilutable in water as a binder, as in Example 4 56.3 Nitrite-containing corrosion inhibitor, 2.5 Butylglycol 3.0 Antifoam, wetting agent, thickener 5.2 - Example 5 A mass Iron phthalocyanine 6.30 Calcium metaphosphate 11.25 Zinc phosphate 6.25 Iriodin® 9504 WR 10.25 Micro-fixed white 6.2 Polymer dispersion dilutable in water, as in Example 4 50.8 Nitrite-containing corrosion inhibitor 2.0 Butyl glycol 2.7 Antifoam, wetting agent, thickener 4.25 a) Exposure to the weather in accordance with DIN 53166 after 6 months: Coating Formation of area proportion ampoules corroded in% Example 5 m! // g 1 approximately 5 b) MACHU test after 3 cycles Coating Formation of area proportion ampoules corroded in% Example 5 m // g < 5 c) VDA 621-415 after 6 cycle; Coating Formation of area proportion ampoules corroded in% Example 5 m / g < 1 mm It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (10)

- 4ó - CLAIMS

1. A pigment preparation, characterized in that it comprises: (i) from 10 to 80% by mass of a support material in the form of plates, coated with a metal oxide, and (ii) from 20 to 60% by mass of an active pigment .

2. The pigment preparation according to claim 1, characterized in that the support material in the form of plates, coated with a metal oxide, is a mica which is coated with titanium dioxide or iron oxide.

3. The pigment preparation according to claims 1 and 2, characterized in that the active pigment is a compound that is capable of converting the primary products of corrosion, which are formed in the defects of an organic coating, into solid compounds that are stable to water.

4. The pigment preparation according to at least one of claims 1 to 3, characterized in that the active pigment is zinc phosphate, zinc borate or calcium metaphosphate.

5. The pigment preparation according to at least one of claims 1 to 4, characterized in that the active pigment is a compound that forms chelate complex, monomeric and / or polymeric, free of metal or containing metal, according to the formulas General I and II: in which A and B each independently of the other are an aromatic or cycloaliphatic radical, which may also contain heteroatoms, such as sulfur, selenium, oxygen and nitrogen, and aryl, alkyl, halogen groups, or which contain -? have oxygen, which contain sulfur or contain nitrogen, as additional substituents, 1 2 R, R, R3 and R4 are hydrogen atoms or alkyl radicals, and Me is iron, nickel, cobalt, manganese, bismuth, tin, zinc or H .

6. The pigment preparation according to at least one of claims 1 to 5, characterized in that the active pigment is a phthalocyanine, tetraarylporphyrin or a tetraazaanulene.

7. The pigment preparation according to at least one of claims 1 to 6, characterized in that the active pigment is a material that binds hydroxide ions.

8- The pigment preparation according to at least one of claims 1 to 7, characterized in that the active pigment is a metaphosphate, bi- or triphosphate, silica gel, silicate, alumino-silicate or calcite.

9. The use of the pigment preparation according to claims 1 to 8, characterized in that it is for anti-corrosion primers.

10. The anti-corrosion coating material, characterized in that it comprises the pigment preparation according to claims 1 to 8.