DE10225979A1 - Coating agent, use and coated substrate surface - Google Patents

Abstract

The invention relates to a coating agent for cellulose-containing substrate surfaces with a liquid phase and binder, the coating agent comprising platelet-shaped pigments and an adhesion promoter, the platelet-shaped pigments being corrosion-resistant and impermeable to UV light, and wherein the adhesion promoter is a bond between pigment, binder and the Cellulose-containing substrate surface causes. The invention further relates to the use of the coating composition according to the invention and coated cellulose-containing substrate surfaces.

Description

The invention relates to a coating agent for cellulose-containing Substrate surfaces with a liquid phase and binder. The invention relates furthermore the use of the coating agent and with the coating agent coated substrate surfaces.

Wood is superficially changed in outdoor weathering and is preserved uneven appearance, which is reflected in brown spots and later in uneven graying manifested. Unprotected wood will last through Weather conditions completely destroyed. The destruction of wood by Weather influences include water or moisture, ultraviolet Attributed to light, oxygen, fungi and animal pests.

From the article "Natural finishes for exterior timber," in Pigment and Resin Technology, April 1986, p. 10 ff., It is known that wood, which rain and Exposed to sunlight, loses its original color. This is partly due to attributed to the extraction of water-soluble components, but especially on the degradation of lignin and other components in the wood by the influence of UV radiation component in sunlight. In practice, it always shows that Damage occurs especially when several influences are effective at the same time.

It is known from EP 0 113 150 to include substrates containing wood or wood fibers an oxidatively drying coating agent based on alkyd resins coat.

WO 91/04305 describes a water-repellent coating composition described the u. a. contains water-soluble metal complex crosslinker. in this connection it is particularly ammonium zirconium carbonate. In addition, you can the coatings contain waxes for further hydrophobization. This However, coating composition disadvantageously offers no protection from Wood versus UV light.

A transparent hydrophobic wood coating dispersion based on organofunctional silanes, is described in WO 93/08006, however due to the transparency no satisfactory long-term protection against UV Light provides.

In wood coating materials there are also UV absorbers, for example transparent iron oxides [symposium by Sachtleben, UV protection agent 2000] used, which keep part of the UV light from the wood, but none provide complete and long-lasting protection against UV light. More UV Protective agents are sterically hindered amines (HALS) from Ciba Geigy [symposium Sachtleben, UV protection agent 2000].

WO 98/22539 also describes nanoscale core-shell Si particles as UV Light absorber known. The particles have a diameter of less than 500 nm on. By suitable thicknesses of the Si core and the coating, the UV Absorption of these particles can be adapted to the incident UV light. Compared to the wavelength of electromagnetic radiation of the visible Range (400-700 nm) these particles behave transparently.

Platelet-shaped metal pigments can be in a coating parallel to Orient substrate. With a sufficiently high pigmentation level, a full coverage against the substrate can be achieved.

Aluminum pigments without a corrosion-resistant coating are suitable not for a coating of wood for outdoor applications, because of the influence of moisture in the wood corrode the aluminum pigments over time and eventually dissolve into alumina. This is particularly disadvantageous if the aluminum pigments of the coating still have a decorative effect lend because the corrosion is accompanied by an optical graying.

A very important aspect is the adhesion of the metal pigments in the coating. Platelet-shaped metal pigments always represent a disturbance in the coating. This can lead to adhesion problems, especially when exposed to water. DE 198 20 112 describes how such liability problems of Effect pigments can be solved by a suitable surface modification can. The surface modification is done with bifunctional additives carried out. On the one hand, these have suitable anchor groups for connection to the effect pigment and on the other hand via suitable terminal functional Groups that allow a connection to the binder of the paint.

The object of the present invention is to provide a reliable and long-term Weather protection for cellulose-containing surfaces, especially wood and Substrates containing wood fibers.

In particular, a coating agent for producing a coating is said to provides long-lasting protection against UV light.

The object on which the invention is based is achieved by a coating agent for Cellulose-containing substrate surfaces with a liquid phase and binder according to Claim 1 solved. The coating agent according to the invention comprises platelet-shaped pigments and an adhesion promoter, the platelet-shaped Pigments are corrosion-resistant and impermeable to UV light and the Adhesion promoter a bond between platelet-shaped pigments, binders and causes the cellulose-containing substrate surface.

Advantageous developments of the invention are in subclaims 2 to 24 specified.

The object is further enhanced by the use of a coating agent one of claims 1 to 24 for coating cellulose-containing Subtrate surfaces, preferably of wood, materials containing wood chips, in particular building materials, or paper or paper-containing materials, solved.

A preferred development of the invention is specified in dependent claim 26.

The object is further achieved by a cellulose-containing substrate surface, which a coating agent according to one of claims 1 to 24 is coated, solved.

A preferred embodiment is specified in claim 28.

The coating agent according to the invention provides an extremely effective UV Protection ready. By using pigments that are opaque to UV light are the cellulose-containing surface of a substrate, for example of wood, completely protected against UV light. The Coating agent contains platelet-shaped pigments, which leads to a complete covering of the substrate surface to be protected. The platelet-shaped pigments are preferably arranged one next to the other adjacent and / or in an overlapping form, d. H. scale-like, on the Substrate surface.

Generally, corrosion-resistant, opaque, platelet-shaped pigments are suitable are opaque to both visible light and UV light.

By using an adhesion promoter that creates a bond between platelet-shaped pigments, binders and cellulose-containing Causes substrate surface, the platelet-shaped pigments are surprising reliably fixed on the substrate surface. It has been shown that one under Use of the coating agent according to the invention Coating over a period of several years, for example more than five to six years, extremely stable under outdoor weather conditions or is stable. This surprising stability of the coating is due to the trained bond between the platelet-shaped pigments, the Cellulose-containing surface and the binder returned.

The coating composition according to the invention is extremely suitable both as Primer on which one or more color coating (s) can or can be applied later, as well as a top coat for Surfaces containing cellulose.

The one produced using the coating agent according to the invention Coating provides both an extremely effective protection of the surface of the Cellulose-containing substrate against UV radiation as well as against Damage caused by wetness. In addition, it has surprisingly been found that it in such a coating does not lead to cracking when the Cellulose-containing substrate, for example of wood, due to thermal Influences or swelling due to absorption of moisture or Water is coming.

Surprisingly, using the invention Coating agent produced coating over a vapor openness or Vapor permeability. This vapor permeability enables the delivery of in the cellulose-containing substrate or between the substrate surface and the applied coating of moisture. This will be extremely beneficial a build-up of pressure under the coating and consequently flaking or peeling off Avoid coating. The using the invention Coating agent applied to a substrate surface vapor-open Coating consequently has a micro- or nanoporous structure which is suitable for Water vapor is permeable.

It is preferred if the platelet-shaped pigments contain metal pigments with a are corrosion-resistant coating.

Metal pigments have proven to be very suitable for the invention Coating agent proven. Metal pigments are in terms of their thickness and their UV reflectivity impervious to UV light. Beyond that too Heat radiation reflected from these pigments. As a result, they contain cellulose Substrate surfaces, for example building materials made of wood or wood fibers, for example chipboard or fiberboard, against UV light and heat radiation (IR radiation) protected. Due to the reflection of the heat radiation it happens less thermal heating of the coated material than without one such coating. In this respect, the coated material is also suitable as Thermal protection or insulation material. Have proven to be very suitable for corrosion coated aluminum pigments.

It is further preferred that the corrosion-resistant coating is selected from the group consisting of an aluminum oxide layer, a silicate layer, preferably an SiO ₂ layer (ie SiO ₂ × nH ₂ O) produced using the sol-gel method, and a chromium oxide layer [EP 0 259 592], acrylate layer [EP 0 416 369], aluminum oxide layer [DE 195 20 312] and layers arranged one above the other.

Such coatings were preferably developed to corrosion-sensitive metal pigments, such as aluminum or zinc pigments, in to be able to use aqueous formulations.

Unprotected aluminum pigments, for example, react to form Hydrogen (gassing). With aluminum, the person skilled in the art has several processes known to protect the pigments with protective three-dimensional layers Mistake.

Coatings made of silicate are preferred. For the purposes of the invention, the term “silicate” is understood to mean both an essentially purely crystalline SiO ₂ coating and in particular a water-containing SiO ₂ layer, ie SiO ₂ × nH ₂ O, produced using the sol-gel process, as in A Kiehl and K. Greiwe, Progress in Organic Coatings 37, 1999, 179.

In particular, metal pigments have proven to be very suitable. Metal pigments coated with oxide layers, for example aluminum oxide, chromium oxide or silicate, preferably an SiO ₂ layer (ie SiO ₂ × nH ₂ O) produced using the sol-gel process, have a sufficient number of hydroxyl groups in the oxide layer which can react or interact with an adhesion promoter, such as the metal complexes described below and / or a functional organosilane.

There is also the possibility of additionally passing through the pigment surface suitable surface modifiers - as in DE 198 20 112 A1 and EP 10 84 198 A1 described - to influence. So in particular chemical functionalities on the surface of the above corrosion-resistant coatings are applied, which is a good Linking the pigment surface to the metal complex and / or the binder and thus an improved adhesive strength of the metal pigment in the applied Allow coating.

In a further development according to the invention, colored ones can also be used Aluminum pigments as described in DE 195 01 307 are used become. Here, color pigments are embedded in the silicate coating and thus on fixed on the surface of the aluminum pigment. These pigments allow more color variants of the coating composition according to the invention.

The above coatings essentially envelop the metal pigments completely, preferably completely. This makes the metal pigments reliable protected against corrosive influences, especially moisture.

According to a further preferred embodiment, the metal pigments are made of Metals selected from the group consisting of aluminum, zinc, tin, Copper, iron, titanium, steel, and alloys thereof, preferably gold bronze, is made.

Coated pigments are preferably used as coated metal pigments Aluminum and its alloys and / or zinc and its alloys used. Aluminum pigments are particularly preferred.

Such platelet-shaped metal pigments are oriented in the coating parallel to the substrate. The thickness of the metal pigments, which is approximately 100 nm to 500 nm is so high that neither UV nor IR radiation can be transmitted. Due to the preferably scale-like arrangement of the metal pigments according to the Application of the coating agent according to the invention on a Cellulose-containing substrate, therefore, is a practically complete UV protection of the underneath lying substrate reached. In particular, aluminum pigments have a high level IR Strahlungsreflektivität. This allows the radiated heat to reach the Environment. The coating suffers less from one through strong temperature changes caused cracking, such as in "paint on Wood: Influences and Interactions ", H. Pecina / O. Paprzycki, Curt R. Vincentz Verlag, Hanover, 1995, ed. Ulrich Zorll, p. 114.

The corrosion-resistant coating of the platelet-shaped pigments from the The aforementioned materials usually have a layer thickness in one area from 5 nm to 400 nm, preferably from 10 nm to 150 nm.

Such platelet-shaped pigments have not yet been used in Wood preservation formulations used.

The coated metal pigments used according to the invention, which are used for the UV Protection of cellulose-containing substrates used are essential circular or oval and preferably have a maximum diameter of 1 µm up to 250 µm, preferably from 5 µm to 70 µm.

The use of metal pigments in the invention Coating agent causes a metallic after application to wood materials Appearance. Coated in this way and therefore against weather influences protected wood materials, such as wooden panels, boards or wooden posts, are ideal as facade cladding instead of metal sheets, Steel beams, Eternit cladding or mineral building materials.

Modern architecture increasingly uses wood as a building material in industrial construction back. This manifests itself in the use of plywood panels, wafer boards, Plywood panels to chipboard. Compared to mineral plates such as Eternit or metallic plates such as aluminum or zinc must be made of wood Systems are usually coated. The currently known Coating systems for wooden facades offer protection for a maximum of 5 years. Afterwards, a post-treatment of the wood is necessary. The invention Coating agent protects wood or wood-like substrates for more than 5 to 6 years outdoor exposure. The with the coating agent according to the invention coated wooden building materials are therefore available for use in industrial construction Available.

A great advantage of such protected wood systems in industrial Facade construction is the lower price of the overall system, improved thermal Room properties when using the coated wood materials Availability of wood in wood-rich areas and the fact that wood is a is a renewable raw material and that the coated according to the invention Building materials metal only in very small quantities, for example in the form of Contain metal pigments.

Silicate-coated aluminum, zinc, Tin, copper, iron, titanium, steel, or gold bronze pigments are used.

According to a preferred embodiment, the adhesion promoter is a metal complex with one or more organic ligands, the metal complex as Central ion (s) contains one or more metal cations (s) from the group consisting of B, Al, Si, Ge, Sn, Pb, Ti, Zr, V, Cr, Mo, Mn, Fe, Zn and mixtures thereof, be selected and the metal complex at least two functional groups or has ligands which form a complex with hydroxyl groups or a form covalent bond or by hydroxyl groups to form a Oxygen central cation bond are displaced from the complex.

It is further preferred that the one or more metal cations Metal cations of the metal complex at least two hydrolyzable inorganic or organic ligands or two hydroxyl ions are coordinated.

Inorganic ligands, for example, can be used as hydrolyzable ligands Halogeno, preferably chloro, carbonato, hydrogencarbonato, etc., or organic ligands, for example alkoxyl ligands, such as methoxy, Ethoxy, propoxy, isopropoxy, butoxy, etc. can be used.

It is further preferred that at least one organic ligand on one Metal cation or the multiple metal cations of the metal complex via one Carboxyl group or several carboxyl groups is coordinated.

Fatty acids with 3 to 30 carbon atoms in particular have proven to be very useful for this proven suitable. It can be mono- or dicarboxylic acids or else Polycarboxylic acids are used.

At least one organic ligand is preferably hydrophobic.

For example, alkyl, aryl, alkylaryl and / or arylalkyl ligands will use. Waxes or fatty acids with at least 9 more preferably used with at least 12 carbon atoms and silicones.

It is further preferred that at least one organic ligand has at least one has functional group with optional components of the Coating agent can react. This ligand can also be added via the have the aforementioned hydrophobic properties. So it can for example a fatty acid with a reactive group or Functionality. This reactive group or functionality can be used with Amino-functionalized silicones are implemented, which increases the hydrophobicity of the ligand is further enhanced.

• a) Neutralisieren einer Carboxylgruppen-haltigen Verbindung, die 3 bis 30 Kohlenstoffatome, vorzugsweise 9 bis 24 Kohlenstoffatome, aufweist, mit einer flüchtigen basischen Stickstoffverbindung, vorzugsweise Ammoniak und/oder einer flüchtigen Aminverbindung,
• b) Zugeben wenigstens eines wasserlöslichen Salzes eines Metalls, das aus der Gruppe, die aus B, Al, Si, Ge, Sn, Pb, Ti, Zr, V, Cr, Mo, Mn, Fe, Zn und Mischungen davon besteht, ausgewählt wird zu der Mischung aus Schritt (a),
• c) gegebenenfalls Zugeben einer flüchtigen basischen Stickstoffverbindung, vorzugsweise von Ammoniak und/oder einer flüchtigen Aminverbindung, zu der Mischung aus Schritt (b).

According to a preferred development of the invention, the metal complex can be obtained by the following steps:

• a) neutralizing a compound containing carboxyl groups and having 3 to 30 carbon atoms, preferably 9 to 24 carbon atoms, with a volatile basic nitrogen compound, preferably ammonia and / or a volatile amine compound,
• b) adding at least one water-soluble salt of a metal selected from the group consisting of B, Al, Si, Ge, Sn, Pb, Ti, Zr, V, Cr, Mo, Mn, Fe, Zn and mixtures thereof becomes the mixture from step (a),
• c) optionally adding a volatile basic nitrogen compound, preferably ammonia and / or a volatile amine compound, to the mixture from step (b).

In step (a), both a mono-, di- or polycarboxylic acid as well as a mixture thereof.

A monocarboxylic acid is preferably used. Have also proven to be suitable Carboxyl group (s) containing wax, fatty acid or silicone resin with carboxyl group proved. The carboxyl group coordinates the carboxyl group (s) - containing compound on the metal cation and thus a fixation in the complex and thus in the applied coating.

The carboxyl group (s) -containing compound used, preferably one Monocarboxylic acid, preferably with ammonia or a volatile amine neutralized. The volatile amine used can be, for example, aminomethylpropanol, Diethanolamine, triethanolamine, etc. can be used

The neutralized mixture prepared in step (a) is washed with a water-soluble Metal salt of B, Al, Si, Ge, Sn, Pb, Ti, Zr, V, Cr, Mo, Mn, Fe, Zn or mixtures of which mixed in an aqueous environment, whereupon a metal complex is obtained.

Mixed metal complexes with different cations of the above-mentioned metals and in the manufacture of the invention Coating agent can be used.

Complexes with Si, Al, Zr and / or Ti as central cations are preferred used. For example, ammonium zirconium carbonate can be used as soluble Metal salt can be used.

Furthermore, those disclosed in European Patent 0 632 109 B1 can be used Coupling reagents, such as zirconium aluminates, in the manufacture of the coating agent according to the invention can be used. This Coupling reagents can be named according to EP 0 632 109 B1 MANCHEM® at MANCHEM LIMITED, Ashton New Road, Clayton, Manchester, M11 4AT, England.

Furthermore, those described in European Patent 0 491 773 B1 described metal complex crosslinking agent in the preparation of the coating agent according to the invention can be used.

A particularly suitable, highly hydrophobicized metal complex is the HF-200 Complex, available from Böhme AG, Bernische Lack- und Farbenfabrik, Stationsstrasse 37, 3097 Liebefeld, Switzerland.

The adhesion-promoting metal complex extremely advantageously causes both adhesion to the binder, to the cellulose-containing substrate surface as well as to Surface of the platelet-shaped pigment, preferably metal pigment, under Formation of a stable and stable network.

The mechanism of the surprising adhesion-promoting effect of the above described metal complex has not yet been clarified. It is believed that the Ligands of the metal complex with the hydroxyl groups of cellulose in the Cellulose-containing substrate surface are implemented. For example, ligands hydrolyze the metal complex under aqueous conditions and am Central cation of the metal complex lead to coordinated hydroxyl ions subsequently condense with the hydroxyl groups of the cellulose. It is also possible to use metal complexes that already coordinated at the central cation Have hydroxyl ions. These hydroxyl ions coordinated at the central cation can with the hydroxyl ions of cellulose with elimination of water Bind the metal complex to the cellulose via an oxygen bridge. Can too Metal complexes are used in which the hydroxyl group of the cellulose Ligands displaced from the metal complex. The metal complex can also over Hydrogen bonds bound to the hydroxyl groups of the cellulose become.

The platelet-shaped pigments show due to their nature Hydroxyl groups on the surface or on the surface of the corrosion-resistant coating on the, as above for the interaction or described with the hydroxyl groups of cellulose, analogously with react or interact with the metal complex.

The platelet-shaped pigments, preferably metal pigments, are preferably included coated at least one corrosion-resistant coating, the reactive Has groups. Of course it is also possible to change the surface of the platelet-shaped pigments or the surface of corrosion-resistant coated platelet-shaped pigments, for example of silicate-coated To provide metal pigments with reactive orientation agents, such as those in DE 198 20 112 are described, the disclosure of which is hereby incorporated by reference is included. Examples include OH group, silanol group, acrylate group, Methacrylate group, amino group, etc. can be specified.

Platelet-shaped pigments coated in this way, preferably metal pigments, react easily with the coupling agent, preferably metal complex and / or one functionalized organosilane (see below) in the invention Coating agents.

According to a further embodiment of the invention, the coupling agent can be a functionalized organosilane R _n SiX _4-n , where n = 0 to 2 and R is a substituted or unsubstituted organic radical, preferably alkyl, aryl, alkylaryl or arylalkyl, and X is functional Groups and / or substituted or unsubstituted organic radicals which form complexes with hydroxyl groups and / or react with hydroxyl groups to form a covalent bond and / or are displaced from the organosilane by hydroxyl groups with the formation of an oxygen-silicon bond. A mixture of different functionalized organosilanes is preferably used.

It is further preferred that in the coating agent as an adhesion promoter Metal complex and a functionalized organosilane is included.

It has been shown that the use of metal complex and functionalized Organosilane leads to a further improvement in the physical properties.

The coating agent according to the invention can be based on water, optionally with the addition of organic solvent, as well as pure solvent-based base. However, are particularly preferred ecological reasons aqueous systems, which preferably consist essentially of There are water and only a small amount of organic solvent contain.

In a preferred development according to the invention, metal complexes are used Silicon, titanium, zirconium and aluminum cations used as central cations.

Surprisingly, it was found that metal complexes with these metal cations result in a particularly significant improvement in rapid weathering tests. This Metal complexes are particularly well suited by reaction with the Hydroxyl groups of cellulose adhere well to the substrate surface cause to bind to functionalities on the pigment surface and optionally react with the binders in the coating composition.

This creates an excellent bond between all components the coating reached. In particular, the platelet-shaped pigments, preferably metal pigments, reliably anchored in the coating. This is This is particularly advantageous if there is a binder lying over the metal pigments the time should be reduced under the influence of UV and moisture.

Another effect of these metal complexes is an additional hydrophobization of the Coating. The water repellency is further improved if the metal complex a ligand with a long-chain branched or unbranched alkyl radical having. For example, the ligand can be a monocarboxylic acid with 9 or more Be carbon atoms such as B. with 16 (palmitic acid) or 18 carbon atoms (Stearic acid). Such fatty acids are neutralized by amines has long been used in wood protection coatings for water repellency. A disadvantage of this has so far been that these salts under the influence of water on the Coating can be washed out over time. With that, the The coating becomes hydrophobic over time Corrosion processes are increasing.

By complexing the preferably used fatty acid over the The fatty acid is fixed in the coating and carboxyl group on the metal cation reliably hydrophobicizes the substrate surface.

In a further embodiment according to the invention, the hydrophobic Properties of the metal complexes by turnover of one or more Ligands with suitably functionalized silicone oils or resins can be improved. The functionalized silicone oils are, for example amino-functional silicone oils, silicone resins or carboxyl-functional waxes.

Examples of such silicone oils and waxes are: Dow-Corning® 2-9034 (nonionic organosilicone emulsion), Baysilone® (available from Bayer AG, Leverkusen, Germany), Crodasil series (available from Croda Resins Ltd.), Silicophen series (available from Tego, Essen, Germany), Ceridust, Licowax (available from Clariant GmbH, Germany).

Among binders that are contained in the coating agent conventional binders equipped with certain functional groups are understood. This can be, for example, monomer functionalities, such as methacrylate or acrylate groups. Are suitable further binders which have one or more free carboxyl groups and / or hydroxyl groups and / or amino groups and therefore have one Implementation with the metal complex and / or the functionalized organosilane enable.

Preferably, the functional groups of the binder with the preferably functionalized surface of the pigments and / or with the Metal complexes are implemented with the formation of chemical bonds. According to the invention, a chemical bond is a covalent bond, Understand ion bonds, hydrogen bonding or complex formation.

Furthermore, those described in WO 93/08006 can also be used organofunctional silanes can be used as binders.

The proportion of binder in the coating composition should not be too high should be chosen, otherwise the vapor permeability of the coatings will suffer could.

Good vapor permeability is important for long periods of weather, because otherwise coatings can flake off due to infiltrating water. The Binder is preferably in proportions of 10 to 20 wt .-%, based on the Total weight of the coating agent contained in the coating agent.

Binders can be used for both aqueous and solvent-based dispersions be used. However, binders for aqueous are particularly preferred Systems.

Examples of such binders are: Mowilith LDM wood glazes (acrylate system available from Clariant GmbH, Division CP, Am Unionspark 1, D-65843 Sulzbach am Taunus, Germany), Primal AC 337 (acrylate dispersion available from Rohm & Haas, In der Kron 4, D-60489 Frankfurt, Germany) or Necowel 6262, Necowel 2275, Necowel 2329 or Necowel 5088 AMP (polyurethane modified alkyd resin; available from Ashland-Südchemie-Kernfest GmbH, Hildenstr. 16-18, P.O.Box 440, D-40721 Hilden, Germany).

The coating composition preferably has a solids content of 10 to 35% by weight, preferably at 15 to 30 wt .-%, based on the total weight of the Coating agent.

The content of metal pigment in the coating composition is 2 to 20% by weight, preferably at 4 to 16 wt .-%, based on the total weight of the Coating agent.

The ratio of platelet-shaped pigments to binder is preferred relatively high and is preferably in a range from 1: 5 to 1: 1, based on the respective parts by weight.

According to a further preferred embodiment, the coating agent can Additives such as fungicides, thickeners, defoamers, auxiliary solvents, Anti-settling agents, other auxiliary binders, etc. contain. Type and amount of this added additives used optionally correspond to the state of the Technology.

Insecticides and / or algicides can also be added.

The coating composition according to the invention is advantageously a 1-component system (One-component system) that after application without adding another Component cures. The hardening takes place after volatilization inhibiting Additives such as ammonia or volatile amines. The basic one The construction of 1K systems is known to the person skilled in the art.

The cellulose-containing substrate is primarily wood or woody fibers. The OH functions of cellulose can be Functions of the metal complex react under condensation and stable Form bonds.

The coating composition according to the invention is used as weather-resistant primer for the coating of wood or wood-like Fibers. The invention therefore also relates to the use of the invention Coated substrates and substrate surfaces produced by coating compositions, such as coated wooden panels, wooden posts, coated Building materials made of wood, etc.

The layer thickness on a substrate surface is extremely advantageous applied coating according to the invention with about 10 μm to 50 μm, preferably 20 µm to 45 µm, more preferably from 30 µm to 45 µm, very thin. In the prior art, covering coatings have a layer thickness of 100 μm and more that are expensive and easily flake off. The invention Coating agent advantageously allows a large saving Coating material.

The invention is explained in more detail below with the aid of a few examples. This However, examples are by no means limitative of the scope of the invention to watch.

Examples example 1 Preparation of a metal complex for use in the invention coating agents

2 g montan wax acid (available from Clariant GmbH, Germany (see above)) and 0.6 g Silicone resin emulsion with the designation Silicophen P40 / W (available from Fa. Tego, Essen, Germany) are added to 94 g of water with stirring. The suspension obtained is heated to 70 ° C to 75 ° C. To the warmed one Suspension is under an equimolar amount of 2-amino-2-methylpropan-1-ol Stirring at 2000 rpm added and the reaction mixture neutralized. Then a small excess of ammonia is added. Below is that Cooled reaction mixture to 30 ° C, and there are 3.4 g Ammonium zirconium carbonate added with gentle stirring. After about 1 hour the complex formation is complete. The complex produced can be used without further Workup can be used in the coating composition of the invention.

Example 2 Production of a coating agent according to the invention

400 g HF-200 (metal complex), 200 g HF 2253 (anti-settling agent) (HF-200 and HF 2253 are both available from Böhme AG, Switzerland (see above)) with intensive stirring with 225 g Necowel 5088 (available from Ashland-Südchemie-Kernfest GmbH, Germany (see above) and 150 g Mowilith LDM 7416 (available from Clariant GmbH (see above)). By adding 250 g of water, a viscosity of 19 to 20 seconds is set in the DIN 4 flow cup. 100 g of Stapa® IL Hydrolan 212 VP 54666 / G (available from Eckart GmbH & Co. KG, D-91235 Velden, Germany) are added to this mixture with stirring: a paste with aluminum pigments containing about 5% by weight SiO ₂ × nH ₂ O are coated) added with stirring. The coating composition of the invention thus produced can be used directly for coating.

Example 3 Artificial weathering test of coated samples

Spruce wood sample boards (21 × 9 cm) were coated by brush application, as indicated in Table 1. First, one or two primer layers (G) and then one or two cover layers (D) were applied, as indicated in the "Coating structure" column. A total of 3 layers were applied. After application of the respective primer, the coating was allowed to dry for 24 hours at room temperature. The top layers were then applied. Table 1

The coating agents Lignol WAB, Aqua-Stop satin, Aqua-Stop matt, Perl-Color gray, Perl-Color stain glaze PC-9 walnut, Satin-Color thick-layer glaze SC-9 walnut, ASS-Grund white, Satin-Color FF-5000 window color RAL 9010 are with the company Böhme AG, Switzerland (see above) are available and do not contain any platelet-shaped Pigments.

The Perl-Color coating system is available from Böhme AG, Switzerland (see above). Platelet-shaped aluminum pigments (Stapa® IL Hydrolan 212 VP 54666 / G (size of the pigment platelets: 60 µm), available from Eckart GmbH & Co KG (see above)) were added to this coating system. This mixture is referred to below as Perl-Color + 10% Stapa® Hydrolan 212. The proportion of Stapa® IL Hydrolan 212 in the Perl-Color mixture was 10% by weight of a paste with 65% by weight solids content and 35% by weight isopropanol. The aluminum pigment consists of approximately 95% by weight aluminum and 5% by weight SiO ₂ × nH ₂ O. The final concentration of aluminum pigment in the Perl-Color + 10% Stapa® Hydrolan 212 is approximately 6% by weight.

The aforementioned coating compositions 1 to 10 each contain the metal complex HF-200 (available from Böhme AG, Switzerland (see above)) in an amount of 40% by weight.

• - 24 h betauen bei 45°C
• - 6 Tage:

abwechselnd:

• - 2,5 h UV-Bestrahlung bei 60°C
• - 0,5 h Beregnen

The sample boards were subjected to rapid weathering based on ENISO 11507 with a QUV device. The tests were carried out by the Federal Materials Testing and Research Institute (EMPA), Überlandstr. 129, 8600 Dübendorf / Switzerland. The QUV device was obtained from Q-Panel Corporation in Cleveland, Ohio / USA and modified for the analysis of wood samples, as in J. Sell and K. Weiss, apparatus for the artificial weathering of wood and wood paints, color + lack, 6/1989, pages 417-418. The sample boards were first conditioned for one week at 23 ° C and 50% relative humidity. The sample boards were then weathered in a QUV device for 2400 h with the following weekly cycle:

• - Defrost for 24 h at 45 ° C
• - 6 days:

alternately:

• - 2.5 h UV radiation at 60 ° C
• - Sprinkling for 0.5 h

The result of the artificial weathering is shown in Table 2. The evaluation was carried out visually, the weathered samples being compared to an unweathered standard. The following evaluation scale was used:
0: no visible change
1: slightly visible change
2: clearly visible change
3: highly visible change
4: very visible change
5: Visible change on the entire sample area Table 2 Result of rapid weathering

The samples coated with aluminum pigments (samples No. 3, 7, 8 and 9) proved to be particularly stable and showed the best result. Surprisingly, samples Nos. 3 and 9, which were above the Aluminum-containing coating had no further top layer without aluminum pigment, the best results. Preservation of the gloss shows that there is no oxidation of the Aluminum pigments came. Furthermore, none of the samples Nos. 3, 7, 8 and 9 a loss of liability in the form of visually visible flaking or Detachments.

In summary, it can be stated that the coating compositions, the contain platelet-shaped pigments, a significant improvement in Weathering stability compared to the comparison samples showed.

Example 4 Weathering of coated wooden panels

• A) Perl-Color + 10% Stapa® Hydrolan 212 (Teilchengröße 60 µm), gleiche Zusammensetzung wie in Beispiel 3 oben
• B) Perl-Color + 10% Stapa® Hydrolan 212 (Teilchengröße 60 µm), Zusammensetzung wie bei Probe (B), jedoch ohne Metallkomplex HF 200
• C) Perl-Color + 10% Stapa® Roto Vario Aqua 610012 (Teilchengröße 18 µm, es handelt sich um ein Aluminiumpigment, welches lediglich durch organische Additive eingeschränkt gegenüber Korrosion stabilisiert ist, jedoch keine korrosionsbeständige Beschichtung aufweist. Das Aluminiumpigment Roto Vario Aqua 610012 wird üblicherweise in Druckfarben verwendet)
• D) Lasurfarbe aus Perl-Color mit 4 Gew.-% deckenden TiO₂- Pigmenten TRONOX CR-800 (erhältlich von Firma Kerr McGEE) und 2 Gew.-% mikronisierten transparenten TiO₂-Pigmenten Hombitec RM 400 WP (erhältlich von Firma Sachtleben (s. o.)) (Bei den TiO₂-Pigmenten handelt es sich um unförmig bis kugelförmige Pigmente, nicht jedoch um plättchenförmige Pigmente)
• E) Lasurfarbe aus Perl-Color mit 4 Gew.-% deckenden Eisenoxidgelb-Pigmente COLANYL-Oxidgelb R 131 (erhältlich von Clariant GmbH (s. o.)) und 4 Gew.-% mikronisierten transparenten Eisenoxidgelb-Pigmente Napronyl-Tr. Oxidyellow L 8020 (erhältlich von Clariant GmbH (s. o.)) (Bei den Eisenoxidgelb-Pigmenten handelt es sich um unförmig bis kugelförmige Pigmente, nicht jedoch um plättchenförmige Pigmente).

The following coating compositions (A) to (E) were used:

• A) Perl-Color + 10% Stapa® Hydrolan 212 (particle size 60 µm), same composition as in Example 3 above
• B) Perl-Color + 10% Stapa® Hydrolan 212 (particle size 60 µm), composition as for sample (B), but without HF 200 metal complex
• C) Perl-Color + 10% Stapa® Roto Vario Aqua 610012 (particle size 18 µm, it is an aluminum pigment which is only stabilized against corrosion by organic additives, but has no corrosion-resistant coating. The aluminum pigment Roto Vario Aqua 610012 is usually used in printing inks)
• D) Glaze paint made from Perl-Color with 4% by weight opaque TiO ₂ pigments TRONOX CR-800 (available from Kerr McGEE) and 2% by weight micronized transparent TiO ₂ pigments Hombitec RM 400 WP (available from Sachtleben (see above)) (The TiO ₂ pigments are bulky to spherical pigments, but not platelet-shaped pigments)
• E) Glaze paint made of Perl-Color with 4% by weight opaque iron oxide yellow pigments COLANYL oxide yellow R 131 (available from Clariant GmbH (see above)) and 4% by weight micronized transparent iron oxide yellow pigments Napronyl-Tr. Oxidyellow L 8020 (available from Clariant GmbH (see above)) (The iron oxide yellow pigments are bulky to spherical pigments, but not platelet-shaped pigments).

Coating agents (A) to (E) were prepared by following the indicated Pigments are introduced into the Perl-Color coating system in the specified amounts were. With the exception of the coating agent (B), the Perl color contained the HF 200 metal complex.

Spruce wood sample boards were coated with the aforementioned coating agents under identical conditions. The coated sample boards were exposed to outdoor exposure for several years. Outdoor weather conditions Location: Bern-Liebefeld, Switzerland
Residential area without large industry
45 ° angle, towards southwest
not a norm

The results are shown in Table 3, and the evaluation was made visually using the evaluation scale given in relation to Table 2. Table 3

A part of the sample boards coated with the coating agent (D) became removed from the weather after two years. Another part of that with the Coating agent (D) coated sample board was removed after four years taken from the weather.

The results shown in Table 3 are in agreement with those in Example 3 Results obtained in rapid weathering. The Coating agent (A) was the one used further for comparison purposes Clearly superior coating agents (B) to (E).

From the direct comparison of the coating compositions (A) and (B) it can be seen that the Using the metal complex HF 200 a very strong improvement in relation on the liability of the applied coating.

The result of the coating agent (C) used shows that the use of corrosion-resistant pigments is very important. In the case of Coating agent (C) already had a strong corrosion after two years Loss of gloss. Those used in the coating agent (A) Aluminum pigments are different from those in the coating agent (C) used aluminum pigments with a corrosion-resistant Silicate coating fully coated.

The results of the coating compositions (D) and (E) used show that the Use of platelet-shaped pigments is very important. in the Case of coating agents (D) and (E) were rated at all get very bad results.

In addition, it was found that the with the invention Coating agent (A) coated wooden boards a surprisingly low Surface contamination. The using the have coatings produced according to the invention (A) therefore a self-cleaning effect.

The coating composition of the invention is therefore also suitable for production of substrate surfaces with a dirt-repellent surface or of Surfaces with a self-cleaning effect.

Because of the reliable adhesion of the coating agent according to the invention on cellulose-containing surfaces and the long-term durability of the produced coating provides an extremely effective UV protection.

Claims (28)

1. Coating agent for cellulose-containing substrate surfaces with a liquid phase and binder, characterized in that the coating agent comprises platelet-shaped pigments and an adhesion promoter, the platelet-shaped pigments being corrosion-resistant and impermeable to UV light, and wherein the adhesion promoter is a bond between platelet-shaped pigments, binders and the cellulose-containing substrate surface. 2. Coating composition according to claim 1, characterized, that the platelet-shaped pigments metal pigments with a corrosion-resistant Coating are. 3. Coating composition according to claim 2, characterized, that the corrosion-resistant coating is selected from the group that made of aluminum oxide layer, silicate layer, chromium oxide-containing layer, acrylate layer and superimposed layers thereof. 4. Coating composition according to claim 2 or 3, characterized, that the metal pigments from metals and / or metal alloys, which from the Group made of aluminum, zinc, tin, copper, iron, titanium, steel, and alloys of which, preferably gold bronze, is selected, manufactured. 5. Coating composition according to claim 4, characterized, that the metal pigments silicate-coated aluminum, zinc, tin, copper, iron, Titanium, steel, gold bronze pigments are. 6. Coating composition according to one of the preceding claims, characterized, functionalized silane on the corrosion-resistant coating of the pigments Surface modifiers are applied. 7. Coating composition according to one of claims 3 to 6, characterized, that in the corrosion-stable coating, preferably a silicate layer, additional color pigments are stored. 8. Coating agent according to one of the preceding claims, characterized, that the corrosion-resistant platelet-shaped pigments, preferably Corrosion-stable metal pigments, which are essentially circular or oval and one maximum diameter from 1 to 250 µm, preferably from 5 µm to 70 µm, exhibit. 9. Coating composition according to one of the preceding claims, characterized, that the coupling agent is a metal complex with one or more organic Is ligand, the metal complex as central ion (s) one or more Contains metal cation (s) from the group consisting of B, Al, Si, Ge, Sn, Pb, Ti, Zr, V, Cr, Mo, Mn, Fe, Zn and mixtures thereof can be selected and the Metal complex has at least two functional groups or ligands with Hydroxyl groups form a complex or form a covalent bond or by hydroxyl groups to form an oxygen-central cation bond be displaced from the complex. 10. Coating composition according to claim 9, characterized, that on the one or more metal cations of the Metal complex at least two hydrolyzable inorganic or organic Ligands or two hydroxyl ions are coordinated. 11. Coating composition according to claim 9 or 10, characterized, that at least one organic ligand on the one metal cation or the several metal cations of the metal complex via a carboxyl group or several carboxyl groups is coordinated. 12. Coating composition according to one of the preceding claims 9 to 11, characterized, that at least one organic ligand is hydrophobic. 13. Coating composition according to one of the preceding claims 9 to 12, characterized, that at least one organic ligand has at least one functional group has, which can react with optional components of the coating agent. 14. Coating composition according to one of the preceding claims 9 to 13, characterized in that the metal complex is obtainable by the following steps: a) neutralizing a carboxylic acid which has 3 to 30 carbon atoms with a volatile basic nitrogen compound, preferably ammonia and / or a volatile amine compound, b) adding at least one water-soluble salt of a metal selected from the group consisting of B, Al, Si, Ge, Sn, Pb, Ti, Zr, V, Cr, Mo, Mn, Fe, Zn and mixtures thereof becomes the mixture from step (a), c) optionally adding a volatile basic nitrogen compound, preferably ammonia and / or a volatile amine compound, to the mixture from step (b). 15. Coating composition according to one of claims 1 to 8, characterized in that the adhesion promoter is a functionalized organosilane R _n SiX _4-n , where n = 0 to 2 and R for a substituted or unsubstituted organic radical, preferably alkyl, aryl, Alkylaryl or arylalkyl, and X represents functional groups and / or substituted or unsubstituted organic radicals which form complexes with hydroxyl groups and / or react with hydroxyl groups to form a covalent bond and / or through hydroxyl groups to form an oxygen-silicon bond are displaced from the organosilane. 16. Coating composition according to one of claims 1 to 8, characterized, that a metal complex according to one of the Claims 9 to 14 and a functionalized silane according to claim 15 is included. 17. Coating composition according to one of claims 1 to 16, characterized, that the liquid phase is selected from the group consisting of water, aqueous Phase, organic solvent or mixtures thereof, preferably Mixtures consisting essentially of water. 18. Coating composition according to claim 13, characterized, that the at least one ligand with the at least one functional group amino functional silicone oil, silicone resin or carboxyl functional wax is implemented. 19. Coating agent according to one of the preceding claims, characterized, that the coating agent additionally reactive binder with at least one contains free carboxyl group, hydroxyl group and / or amino group. 20. Coating composition according to one of the preceding claims, characterized, that in the coating agent about 2 to about 20 wt .-% corrosion resistant Pigments, preferably about 4 to 16% by weight, based on the Total weight of the coating agent are included. 21. Coating composition according to one of the preceding claims, characterized, that in the coating agent about 10% by weight to 20% by weight of binder, based on the total weight of the coating composition. 22. Coating agent according to one of the preceding claims, characterized, that the total solids content in the coating composition is about 10 to 35% by weight, preferably about 15 to 30 wt .-%, based on the total weight of the Coating agent. 23. Coating composition according to one of the preceding claims, characterized, that the coating composition also contains additives, such as fungicides, insecticides, Ablgicides, thickeners, defoamers, anti-settling agents, auxiliary binders and / or Auxiliary solvent. 24. Coating composition according to one of the preceding claims, characterized, that the cellulose-containing substrate surface contains wood, wood chips Contains materials, paper and / or paper-containing materials. 25. Use of a coating agent according to one of claims 1 to 24 for coating cellulose-containing substrate surfaces, preferably wood, Materials containing wood chips, in particular building materials, or paper or paper-containing materials. 26. Use of a coating composition according to claim 25 for priming of cellulose-containing substrate surfaces for the production of weather-resistant Components and cladding. 27. cellulose-containing substrate surface, characterized, that the substrate surface with a coating agent according to one of the Claims 1 to 24 is coated. 28. cellulose-containing substrate surface according to claim 27, characterized, that the substrate surface is the surface of wood material, wood-containing material, Paper, paper-containing material or of chemical and / or physical is modified wood material.