DE10164636A1 - Mixture for coating glass or ceramics contains coating components and a component convertible to a glass, in the form of a solution, dispersion or gel - Google Patents

Abstract

A mixture for coating preparation contains at least (a) coating components and (b) components which can be converted to a glass, either in a solvent-soluble form, or in a form dispersible in a dispersion medium of particle size below 1 micron, or in the form of sol capable of gelation. An Independent claim is also included for a process for preparation of a coating in which the mixture is first applied to the surface of an object and the coated object is subjected to heat treatment.

Description

The invention relates to a mixture and a method to create a coating.

Coatings can, for example, on glass or Ceramics, for example to create a decor, be applied.

As coating components are, for example Precious metals in the form of polished gold, shiny gold, or matt gold Chandelier known that directly on the surface to be coated Surface can be applied. precious metal preparations can also from solutions of platinum, or palladium Gold resinates with or without flux or adhesive in Powder form exist. As a flux or adhesive, Cr, Ni, Bi or V used in organic compounds become. Rh is mostly used as a brightener.

If such a coating becomes a decor on a Applied on the surface, it exists after baking from a very thin metal film with a thickness of about 0.01 to 2 µm, which by ion diffusion at the Surface adheres. Because of the different Composition of the surface on the one hand and the Metal films, on the other hand, are special Trouble. For example, liability is only very unsatisfactory. It turned out to be particularly bad Adhesive strength of such decorations on glass objects, which are baked at temperatures of around 580 ° C. Such a thin one tends to ceramic with soft glazes Cracking film.

In the case of interference and metallic colors, it is known to burn in mica particles coated with an oxide or a noble metal preparation as luster pigments, mixed into a glass flow. As a glass flow, frits consisting, for example, of SiO ₂ , Al ₂ O ₃ , PbO, B ₂ O ₃ , Na ₂ O and other oxides are premelted and ground.

Such decors are mostly overglaze decors.

When creating a decor using in one Glass flow distributed gloss pigments mostly result however, the problem is that the luster pigment flakes in the raw material mix for creating the decor very much are distributed irregularly and therefore not uniform Can form a layer on the surface.

Due to the irregular distribution of the gloss pigments, mostly with a particle size distribution between 10 and 60 microns, their share can be a maximum amount to only about 25% by weight of the total mixture. The milled glass flow usually has one Particle size distribution between 1 and 60 microns. With such a grain distribution between Coating component and glass flow can use of platelets with a reflective surface as Coating component in a glass flow, for example cause the platelets to have no continuous, level surface Form surface so that the glossy effect caused by the platelets to be created, aesthetically extreme is unsatisfactory.

A corresponding method is known from DE 38 35 402 C1 known for the production of decors. Doing so with a metal oxide coated mica plate into one Glass flow mixed in and then on a so coated surface baked. Because here too Mica flakes are very irregular in the glass flow, can contain a maximum of 25 wt .-% mica flakes in the Total mixture is available. The gloss effect of this decor is also unsatisfactory.

The invention has for its object a mixture and a method for creating a coating for To provide, the mixture well on a Surface adheres and being an improved arrangement of the coating component on the surface becomes.

Among other things, it has been recognized in the context of the invention that that improved alignment of the Coating component on the to be coated Surface can be reached when the Component in which the coating component for Apply to the surface, either liquid (pastos) is present or in a specific Particle size.

• - Beschichtungskomponente und
• - einer in ein Glas überführbaren Komponente, die
• - entweder in einer in einem Lösungsmittel lösbaren Form vorliegt
• - oder die in einer in einem Dispersionsmittel dispergierbaren Form und in einer Partikelgröße unter einem Mikrometer vorliegt.

To achieve this object, the invention proposes a mixture for creating a coating with the following components:

• - coating component and
• - a component that can be transferred into a glass, the
• - either in a form that is soluble in a solvent
• - Or which is in a form dispersible in a dispersant and in a particle size below one micrometer.

In such a mixture, the Coating component, for example particles in the form of platelets from a coated substrate, align slightly, because the component of the Coating component when not aligned "in Way ". So the coating component can in particular form a continuous layer. Equal in time the mixture can surface to which it is applied should be applied, adjusted.

Because the degree of order of the coating component can be much higher than before - the Coating component can be in the mixture according to the application essentially in one or several essentially parallel to the coated Align surface trending layers while they are in the previously known mixtures "House of cards structure" showed - can Coating component a high proportion of the Make up the total mix. The share of Coating component in the overall mixture can for example between 20 and 90 percent by weight Example also between 30 and 90 percent by weight, between 50 and 90 percent by weight or between 70 and 85 percent by weight, each based on the weight of the Total mix, lie. Overall, the share of Coating component thus significantly above the proportions lie in which he with the usual glass flows was applicable.

The coating component can, for example, in a average particle size between 1 and 100 µm, thus also between 20 and 80 µm or between 30 and 60 µm are present. It can thus far exceed the average particle size of the dispersible, in a glass transferable component is present.

The component which can be converted into a glass can be constructed, for example, on the basis of SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , other components forming a glass network (“network formers”) or mixtures thereof.

In contrast to the prior art, the glass in the Burn-in process "in-situ" on the surface to be coated Surface formed from the raw materials. The so far necessary additional melting and grinding process for This eliminates the need to manufacture the glass frit.

According to the application, "can be transferred into a glass" means that this component through suitable treatment steps, especially drying and temperature Treatment steps, in a glassy (isotropic) solidifying Melt (a glass) can be transferred.

The component that can be transferred into a glass can also cumulatively both components in one in one Solvent-soluble form as well as components in a form dispersible in a dispersant contain.

As far as the component that can be transferred into a glass in one is in a solvent soluble form, this can Component must first be dissolved in a solvent. In this form, the coating can be applied to the coating surface can be applied. Anschießend can the solvent, especially by Drying steps, at least partially removed, and the component that can be transferred into a glass Heat treatment steps transferred into a glass become.

As a solvent for dissolving the soluble component For example, polar or non-polar solvents, for example in the form of Shellsol® (brand of the German Shell Chemie GmbH), cyclohexanol, each individually or in Have mixture. These solvents can be found under also for dissolving temporary binders in serve the mixture (see below). Basically anything can Solvents are used, but especially organic solvents. Depending on the application Solvents with different degrees of dryness are used become. For example, cyclohexane is good for screen printing suitable and dichloromethane for brush application.

As far as the component that can be transferred into a glass in one in a dispersible form (one Suspension) is present, this component can initially be in be dissolved in a dispersant. In this form can apply the coating to the surface to be coated be applied. Then that can Dispersing agents, in particular by drying steps, at least partially removed and put in a jar now convertible component Heat treatment steps transferred into a glass become.

The average particle size of the dispersible Particles can, for example, be under a micrometer are, for example, also less than 800 nanometers, less than 500 nanometers, less than 200 nanometers, less than 100 Nanometers, less than 50 nanometers or even less than 30 Nanometers.

To the coating, especially after volatilization of the solvent or the dispersant and before fire, improved strength too can give binders added to the coating become.

Temporary binders can be used Binding agent that initially binds after it has hardened Have properties and later, especially after a heat treatment of the mixture, at least can partially go into the gas phase.

For example, organic (temporary) binders, such as polymeric binders based on a natural or synthetic resin may be provided.

As a further component, the mixture can be a or several network converters, for example one or more Salts, for example metal salt or at least the salt a polycarboxylic acid (polycarboxylic acid salt) or a Organometal included.

These so-called network converters are in the network the components forming the glass ("network builder") built-in.

Through the network converter, for example Temperature at which the components forming the glass must be heated to melt affected become. Examples of network converters are Na, K, Li, Zn, Co, Bi or B. Many of these network converters, for example metal ions of Fe, Cr, Ti, Ce, Au, Ag, Sn or Go, can also have a coloring effect on the glass exercise what can be used specifically.

The coating component can be decorative and serve cumulatively or alternatively technical purposes.

The coating component can be, for example coated substrate or pigment, each individually or in combination with each other.

The coated substrate can be in platelet form available. Because it turned out that Coating platelets after being in the mixture according to the invention on a surface have been applied, essentially flat, that is Align parallel to the surface. They form through it a good reflective surface for light what a aesthetically extremely appealing impression. Correspondingly by a mixture according to the application a surface applied coating component therefore creates a beautiful gloss effect on the coated surface.

In principle, any substance that is stable in the mixture can be used as the substrate, for example glass, ceramic or a mineral. The mineral can be, for example, a mica. In particular, oxide ceramics based on SiO ₂ , Al ₂ O ₃ , ZrO ₂ , individually or in combination, can also be used as the ceramic.

The substrate can be coated, for example, with a noble metal, for example gold, platinum, palladium or silver and alternatively or cumulatively with an oxide, for example a metal oxide, for example Fe ₂ O ₃ or TiO ₂ .

Correspondingly coated platelets are, for example under the Variocrom® brands (BASF brand) or Iriodin® (trademark of Merck KGaA) known.

The mixture can have different other components can be added, for example in the form of Defoamers, plasticizers or wax additives.

The mixture can be offered ready for application, So, as far as the component that can be transferred into glass can be detached is already dissolved in a solvent or, as far as the glass can be transferred Component is dispersible in a dispersant dispersed.

According to one embodiment it is provided that the in a glass transferable component in the form of a gelable sol is present, i.e. in the form of a sol that can react to a gel.

For the purposes of the invention, sol is generally one Understood solution in which a solid or liquid substance in fine to very fine distribution in a liquid Medium is dispersed or dissolved.

The pre-made remarks on solvable respectively dispersible components that can be transferred into a glass apply accordingly to what can be transferred into a glass, Solvable or dispersible, gellable sol.

By solidification reactions, for example a Polymerization of components of the sol can result from gel the sol.

Procedures in which a gel is made from a sol can be found under the term "sol-gel process" especially from glass and ceramic technology known. Because sol-gel processes can be used for glass or use ceramic synthesis.

In a sol-gel process, a solution is more soluble Components, especially monomeric components, by Hydrolysis steps first a sol. This sol can be under Solidification to a gel react further and finally into a polymeric inorganic solid be transferred.

For the synthesis of a glass using the sol-gel process several methods are known.

In one method, a sol is made by Metal alcoholates with water or organic compounds can react, resulting in hydrolysis of the metal alcoholate leads. Before the hydrolysis, the metal alcoholate an additional organic compound, for example a base or an acid such as Acetic acid, to be added to its stabilization complete hydrolysis of the metal alcoholate prevent. The (partially) hydrolyzed metal alcoholates can polymerize with each other. It is formed three-dimensional networks. To gel the sol this destabilizes, for example by withdrawing the Solvent. Polymerization can now be carried out via the entire volume of the sol take place. It imagines Gel, which is essentially characterized in that every particle is built into a network and all Particles are interconnected.

Another sol-gel process, the so-called Alkoxide processes, organometallic compounds, for example monomeric silanes such as tetraethyl ortho Silicate (tetraethoxysilane; TEOS) used in organic Solvents are used. In the sol can Mixtures of tetra and trifunctional Matrix formers, for example tetraethoxysilane or Trimethoxymethylsilane, or difunctional reactants, for example dimethoxydimethylsilane. It is also possible, for example, with relative silanes long organic residues, for example alkyl chains or Phenyl residues to condense into the matrix.

Here too, hydrolysis steps are followed polymeric structures built up to form a gel to lead. The macroscopic properties of the after Gelation of the resulting solid, such as Porosity, specific surface or degree of crosslinking, can by the used in the sol-gel process Components and through the choice of reaction conditions to be influenced.

The sol can also be in the form of one in one Dispersant dispersed component are present. The colloidal process is followed, in which one of a dispersion of existing solid Colloids in a liquid phase. The transition There are two ways to go from sol to gel. To the one by destabilizing a sol due to the Change in the surface charge of the colloids. at slow coagulation leads to flocculation of denser agglomerates, which then sediment. Only at very rapid coagulation forms filling the space "Agglomerates" which include solvents and build a gel with it. The second way is further polymerization of the molecular solution via the Sol out to a space-filling fixed too Structure, which then also the solvent and builds up the gel. Both processes can also run in parallel if, for example, the agglomerated colloids through polymerization reactions be chemically bound together.

The gel can be dried by Heat treatment steps transferred into a glass become.

The use of a mixture according to the application is, for example, as follows:
First, the components of the mixture are mixed with one another, the component which can be converted into a glass, insofar as it is soluble, being dissolved in a solvent or, insofar as it can be dispersed, dispersed in a dispersing agent.

Through the selection, also possibly additional ones, Components as well as the choice of the ratio of Components can have the properties of each other Mix can be set.

For example, the rheology and viscosity the mixture can be adjusted. Blends with Lower viscosity can, for example, on the Surface printed, sprayed on or with a brush be applied. Mixtures with higher viscosity can, for example, with decals, Direct screen printing, screen printing, offset printing or pad printing Pressure is applied to the surface.

The mixture applied to the surface becomes Drying (and if necessary gelation of the sol) subjected to a temperature treatment.

This can be, for example, between 450 ° and 1,400 ° C, for example between 480 ° C and 1,250 ° C or between 750 and 880 ° C.

The mixture is then allowed to cool.

Basically, the mixture can be applied to the surface of a any object, for example an object made of ceramic, glass, metal or Plastic.

The mixture as well as the process for producing the The coating is attached to the base material to which the Mixture should be applied, adjusted. So can for example for high-temperature decor mixes selected for temperatures up to 1,250 ° C are suitable. For example, at Base materials that can withstand higher temperatures for example ceramics, in the heat treatment higher temperatures can be chosen, for example up to 1,400 ° C. For base materials, the lower one Can withstand temperatures, such as glass for example temperatures between 480 ° C and 600 ° C or with enamel, for example, between 750 ° C and 880 ° C to get voted.

In addition to the advantages mentioned above, the Coatings, among other things, due to their high strength and high adhesion resistance on the coated Surface.

With a suitable selection of the coating component can Decors are made for microwave ovens are suitable. Most precious metal decors with classical methods are not suitable for microwaves.

It has been found that the mixture becomes Applying a coating on circuit boards is suitable. The mixture can be applied, for example a noble metal layer, for example one Gold layer, used on a circuit board by precious metal or a coating component Component containing precious metal is used.

Claims (15)

1. Mixture for creating a coating with at least the following components: a) coating component and b) a component that can be transferred into a glass, the c) either in a form that is soluble in a solvent d) or which is in a form dispersible in a dispersing agent and in a particle size of less than one micrometer e) or which is in the form of a gelable sol. 2. Mixture according to claim 1 with a further component in Form of a salt or an organometallic compound. 3. Mixture according to claim 2, wherein the salt or organometallic compound one or more components of the series Si, Al, B, Bi, Ca, Zn, K, Na, Ti, Fe, Co, Sr, Li, Mg, Cr, Ce, Sn, Au, Pt, Pd or Ag. 4. Mixture according to claim 1 with a Coating component in the form of a coated Substrate. 5. Mixture according to claim 4 with a substrate made of ceramic, Glass or a mineral. 6. Mixture according to claim 4 with a plate-like Substrate. 7. Mixture according to claim 4, wherein the substrate with a Precious metal or a metal oxide is coated. 8. Mixture according to claim 1 with a further component in the form of a binder. 9. Mixture according to claim 8 with a temporary Binder. 10. Mixture according to claim 9 with a temporary binder in Form of a resin. 11. Mixture according to claim 1 with a further component in the form of a solvent. 12. Mixture according to claim 1 with a further component in the form of a defoamer, a plasticizer or one Wax additives, individually or in a mixture. 13. Mixture according to claim 1, wherein the in a glass convertible, solvent-soluble component is dissolved in a solvent. 14. Mixture according to claim 1, wherein the in a glass convertible, dispersible in a dispersant Component is dispersed in a dispersant. 15. Process for creating a coating, in which a Mixture according to claim 1 first on the surface an object is applied and the coated Subsequent heat treatment is subjected.