EP4347520A1

EP4347520A1 - Method for producing a color coating

Info

Publication number: EP4347520A1
Application number: EP22728638.2A
Authority: EP
Inventors: Marya KHAN; Dagmar Korbelarz; Andreas Schulz; Dietrich Speer
Original assignee: Ferro GmbH
Current assignee: Vibrantz GmbH
Priority date: 2021-05-31
Filing date: 2022-05-24
Publication date: 2024-04-10
Also published as: WO2022253624A1; DE102021114007A1

Abstract

The present invention relates to a method for producing a color coating on a glass surface by way of a printing method. According to the method, A) a printing substance is applied to a glass surface, the printing substance comprising at least one pigment precursor; and B) the pigment precursor applied to the glass surface is converted to pigment particles. The present invention also describes a printing substance for carrying out the method and a coated glass substrate.

Description

Method of making a colored coating

The present invention relates to a method for producing a colored coating, a printing substance for carrying out the same, and a coated glass substrate.

The use of enamel compositions on glass substrates, in particular glass panes for automobile construction, is known. This is done, for example, to achieve decorative and protective effects (EP1289897 by St. Gobain and EP3365291 by Pilkington). For this purpose, black screen printing color pastes are used, which contain approx. 80-90% solids, which in turn consist of approx. 80% of a glass frit, usually containing bismuth, and approx. 20% of a black pigment (preferably pigments of the spinel system , e.g. CuC^C ).

In EP1893541 and WO 2006/134356 by Pilkington, a method is claimed which is particularly suitable for use in roof glazing. These glasses have an optical transmission of 10-50%, which corresponds to an optical density of 1 to 0.3. (The optical density is the negative logarithm of the percentage transmission.) Inks are used here - also digitally printable - that are based on finely ground pigments and glass frits with particle sizes <1.2 pm with a pigment content of 5-15%. The compositions of such inks, which have a low viscosity of about 20 mPas, are described in WO 2005/019360 by Ind. Techno. logic. Solutions described.

The enamel compositions set forth above serve, among other things, to form the opaque perimeter band found on the windshield, side windows, skylight and rear window of a motor vehicle. By absorbing UV radiation, it preserves the integrity of the adhesive under the glass pane after it has been installed in the bodywork opening by means of a bonding operation. Such enamel colors are also suitable for the decoration of skylights.

In general, the enamel compositions are formed from a powder containing a glass frit, pigments, a solvent or suspending agent and others Additives included. The glass frit serves to form a glass matrix, with the pigments being able to be a component of the frit.

The pigments contained as colorants are, in particular, gray or black. The pigments are mostly metal oxides such as copper, chromium, cobalt, nickel and iron oxides, which do not react with the other components of the composition. The suspending agent and combination with suitable organic binders and viscosity-controlling additives ensure the necessary stable suspension of the solid particles and the adhesion of the ink or printing paste to the glass substrate. The suspension medium is generally based on organic solvents, such as are used in a wide variety of printing inks (alcohols, glycols, etc.).

The actual decoration firing, in which the enamel composition - i.e. ultimately the color layer - is firmly fused with the glass substrate, preferably takes place at temperatures of 600 to 700°C, with the glass plate being exposed to the maximum temperature for approx. 3.6 minutes.

The known enamel compositions can be used in accordance with the methods set out above for printing on glass. However, it is often necessary to produce small pigments in order to obtain a low viscosity. This is very time-consuming. A major problem, however, is that the coatings obtained with the enamel compositions presented above cause a sharp reduction in transverse rupture strength. This means that the uncoated glass substrate has a much higher transverse rupture strength than the glass substrate coated with conventional enamel compositions.

In view of the prior art, it is now the object of the present invention to provide a coated glass substrate with a coating which causes a slight decrease in the transverse rupture strength, based on the transverse fracture strength of the uncoated glass substrate.

In view of the state of the art, it is a further object of the present invention to provide a printing substance for coating glass surfaces, which provides a coating that causes a small decrease in transverse rupture strength relative to the transverse rupture strength of the uncoated glass substrate.

Furthermore, the coating should have high adhesion to the glass substrate. A further object is to provide a printing substance which results in a coating with high adhesion on a glass substrate.

In addition, the coating obtained from the printing substance should have the highest possible acid and scratch resistance. Furthermore, the printing substance should be able to be obtained as simply and inexpensively as possible. Furthermore, the printing method based on this should be able to be carried out with low costs and high efficiency.

These and other problems not explicitly mentioned, which can be easily derived or deduced from the context discussed in the introduction, are achieved by a coated glass substrate having all the features of patent claim 1. Appropriate modifications of the glass substrate according to the invention are protected in the subclaims. With regard to the method for producing a coated glass substrate and the printing substance for carrying out the method, the subject matter of claims 10 to 23 provide a solution to the underlying problem.

The subject matter of the present invention is a coated glass substrate, the coating comprising an inorganic glass matrix and pigment particles, characterized in that the coating in the burned-out state has a thickness in the range from 0.6 μm to 8 μm and the color values of the coating in the range for L * < 15, for a* between -5 and +6, for b* between -4 and +5.

As a result of these configurations, glass substrates with a colored coating exhibit a high bending strength. The colored coating shows high adhesion on the glass substrate. This coating essentially corresponds to coatings as are known from the prior art for corresponding purposes. The colored one Coating is based on a glass matrix that is inorganic in nature. The color is caused by pigment particles obtained in step B) of the process detailed later. Further details of the colored coating result from the description given later of the printing substance to be preferably used.

Furthermore, it can be provided that the part of the glass substrate provided with a coating has an optical density of at least 1.0, preferably at least 2.0, particularly preferably at least 3.0. The optical density can be measured using conventional methods, including using a transmission densitometer, for example a Gretag D 200-11. Measurement method 1, as set out in the operating instructions, can preferably be used here.

Furthermore, it can be provided that the coating of the glass substrate comprises pigment particles, the pigment particles having an average particle diameter in the range from 0.05 μm to 0.8 μm, preferably from 0.08 μm to 0.8 μm, particularly preferably from 0.1 to 0 .5 pm where the average size is determined from the numerical mean of scanning electron micrographs using at least 20 pigment particles.

In addition, it can be provided that the coating of the glass substrate has a scratch resistance of at least 5 N, measured with a scratch hardener model 318 with rollers 1.0 tip from Erichsen.

Furthermore, it can be provided that the glass substrate is selected from a front window, a side window, a rear window and/or a roof window of a motor vehicle. The usual skylights of a motor vehicle include, for example, panoramic roofs or panoramic sunroofs.

Furthermore, it can be provided that the glass substrate is only coated on part of the glass surface. Provision can also be made for at least one network former pre-connection and/or at least one network converter pre-connection to form a glass matrix. The glass matrix acts as an adhesion promoter or adhesion promoter between the substrate and the pigment.

It can advantageously be provided that the coating applied to the glass substrate does not completely cover the glass substrate, preferably the coating applied to the glass substrate covers the edge of the glass substrate, the edge covered by the coating preferably having a width in the range from 0.5 cm to 20 cm, preferably in the range 0.5 cm to 5 cm, and the glass substrate has an inner uncoated area surrounded by the rim.

In addition, it can be provided that the coating in the burned-out state has a thickness in the range from 0.8 to 4.0 mm and particularly preferably in the range from 1.0 to 3.0 mm.

Furthermore, it can be provided that the color values of the coating applied to the glass substrate are in the range for L*<5, for a* between −1 and +1 and for b* between −1.7 and +1.5. Further preferred color values of the coating applied to the glass substrate are set out later, and reference is made thereto.

Another object of the present invention is a method for producing a coated glass substrate according to the present invention with a printing process in which one

A) applying a print substance to a glass surface, the print substance comprising at least one pigment precursor; and

B) converting the pigment precursor applied to the glass surface into pigment particles by a heating step.

This configuration makes it possible to obtain a colored coating on glass surfaces which, in relation to the glass substrate, only decreases very slightly cause the transverse rupture strength. The colored coating obtained on a glass substrate shows high adhesion.

In addition, the colored coating obtained from the printing substance has a very high acid and scratch resistance. In particular, the colored coating withstands the usual loads.

Furthermore, the printing substance can be obtained simply and inexpensively, and the printing process based thereon can be carried out very easily using known systems. Furthermore, the printing process can be carried out with very high throughput rates.

In step A) a printing substance is applied to a glass surface. In principle, this can be done using any customary printing method, in which case the viscosity values of the printing substance can be adapted to the method with which the printing substance is applied to the glass surface. However, it has turned out to be preferred that the printing substance in step A) is applied to the glass surface by ink jet printing or screen printing, preferably screen printing.

The printing substance applied to a glass surface in step A) comprises at least one pigment precursor. Particularly suitable pigment precursors are described in connection with printing substances which are to be used with preference.

In step B), the pigment precursor applied to the glass surface is converted into pigment particles. This conversion of the pigment precursor into pigment particles can be accomplished by any suitable method, dictated by the nature of the pigment precursor. The pigment precursor applied to the glass surface in step B) can preferably be converted into pigment particles by a heating step.

The heating step which is preferably provided for converting the pigment precursor into pigment particles can comprise a number of sub-steps, ie especially steps or ramps to get to a suitable temperature. It can preferably be provided that the heating step involves firing the coated glass surface to a temperature in the range from 400° C. to 1000° C., preferably 550° C. to 750° C., particularly preferably 620° C. to 700° C., particularly preferably 650° C to 690°C.

Furthermore, it can be provided that the heating step is carried out over a period of 1 minute to 180 minutes, preferably 1 to 20 minutes, particularly preferably 1 to 5 minutes. A temperature in the range from 400° C. to 1000° C., preferably 550° C. to 750° C., particularly preferably 620° C. to 700° C., especially preferably 650° C. to 690° C., is particularly preferred for the times mentioned 1 minute to 180 minutes, preferably 1 to 20 minutes, more preferably 1 to 5 minutes.

The coating thickness with which the printing substance is applied to a glass surface in step A) (wet layer thickness) can be within a wide range. Provision can preferably be made for the printing substance in step A) to be applied to a glass surface in a thickness in the range from 0.5 μm to 40 μm, preferably from 1 to 20 μm. In a further preferred embodiment it can be provided that the coating thickness with which the printing substance is applied to a glass surface in step A) is in the range from 0.5 μm to 40 μm, preferably 10 to 30 μm.

The process of the present invention is particularly useful for forming an opaque perimeter band to be created on the windscreen, side windows, skylight and rear window of a motor vehicle in order to preserve the integrity of the adhesive underlying by absorbing UV radiation of the glass pane after it has been installed in the body opening by means of a bonding process. The process is also suitable for decorating skylights. It can therefore be provided that the printing substance in step A) is only applied to part of the glass surface.

Furthermore, it can be provided that the printing substance has at least one network former pre-connection and/or network converter pre-connection and comprises at least one pigment precursor, wherein the pigment precursor is soluble in an organic solvent, and the pigment precursor comprises at least one transition metal. The printing substance particularly preferably comprises at least one network former pre-compound.

The type and amount of pigment precursor depends on the pigment particles to be obtained from the pigment precursor. Here, the pigment precursor can be used as a single compound or as a mixture of two, three or more pigment precursors. The pigment precursor preferably comprises at least one transition metal convertible into pigment particles.

Provision can preferably be made for the transition metal contained in the pigment precursor to be selected from cobalt, iron, nickel, manganese,

Chromium, copper, aluminum, titanium, molybdenum, preferably cobalt, iron, chromium, copper, manganese, particularly preferably cobalt or iron.

Furthermore, it can be provided that the transition metal contained in the pigment precursor is selected from iron, nickel, manganese, chromium, copper, aluminum, titanium, molybdenum, ruthenium, preferably iron, chromium, copper, manganese, particularly preferably iron and chromium or copper, chromium, iron or copper, manganese, iron or copper and manganese.

Provision can particularly preferably be made for the transition metal contained in the pigment precursor to consist of cobalt or a mixture of cobalt and iron or a mixture of manganese, iron and copper or a mixture of manganese and copper or a mixture of copper and cobalt.

In step B) of the process set out above and below, the pigment precursor is converted into pigment particles. The pigment particles obtained preferably correspond to the pigments known from the prior art which are used for the purposes mentioned and are preferably metal oxides such as copper, chromium, cobalt, nickel and iron oxides, with mixed oxides also being known. Pigment particles that are preferably obtained are preferably oxides, such as, for example, spinels, for example CO 3 O 4 , and also silicates, etc., such as are used in the prior art set out in the introductory part of the present application.

The pigment precursor is preferably an organic solvent-soluble complex and/or an organic solvent-soluble salt of a transition metal. The ligand and/or salt component which can be used include amines such as diethyleneamine, bipyridyl, terpyridine,

ethanolamine, diethanolamine or triethanolamine; Alcoholates, hydroxides, sulfates, sulfonates, carbonates, carboxylates and / or other carbonyl compounds are used. Preferred sulfonates include salts and/or complexes of methanesulfonic acid. The preferred carboxylates, which particularly preferably correspond to the formula (CH C _n H _n COO- with n=0-18), include decanoate, neodecanoate, 2-ethylhexanoate, cyclohexanoate, acrylates, oleates, benzoates. Furthermore, dicarboxylic acids can be used to form the complexes and/or salts, which particularly preferably correspond to the formula (HOOCC _n H2nCOOH with n=0-10), such as oxalic acid, malonic acid, or sebacic acid, maleic acid or fumaric acid. Furthermore, as a ligand and / or salt component, hydroxycarboxylates such as derivatives of glycolic acid, lactic acid, malic acid, mandelic acid, tartaric acid, citric acid, and / or ketocarboxylates such as salts / complexes of glyoxylic acid, pyruvic acid, acetoacetic acid or ethyl acetoacetate and / or amino carboxylates such as salts/complexes of amino acids such as glycine, alanine, valine, leucine, isoleucine, phenylalanine, tyrosine, proline, hydroxyproline, serine, threonine, cysteine, cystine, methionine, tryptophan, aspartic acid; Glutamic acid, arginine, lysine, histidine can be used.

It can be provided here that the pigment precursor is a complex which is soluble in an organic solvent, for example: with the ligands diethyleneamine, bipyridyl, terpyridine, ethanolamine, diethanolamine or triethanolamine and/or alcoholates, acetylacetonates, carboxylates (CH C _n H _n COO- with n = 0-18), such as: decanoate, neodecanoate, 2-ethylhexanoate, cyclohexanoate; but also an unsaturated carboxylate such as salts/complexes of acrylic acid, oleic acid, benzoic acid, Etc.; and / or a dicarboxylate, such as salts / complexes of dicarboxylic acids (HOOCCnbhnCOOH with n = 0 - 10) such as oxalic acid, malonic acid, or sebacic acid or salts / complexes of unsaturated dicarboxylic acids such as maleic acid or fumaric acid and / or hydroxycarboxylates, such as example salts/complexes of glycolic acid, lactic acid, malic acid, mandelic acid, tartaric acid, citric acid; and/or ketocarboxylates, such as salts/complexes of glyoxylic acid, pyruvic acid, acetoacetic acid or ethyl acetoacetate; and/or amino carboxylates such as salts/complexes of amino acids such as glycine, alanine, valine, leucine, isoleucine, phenylalanine, tyrosine, proline, hydroxyproline, serine, threonine, cysteine, cystine, methionine, tryptophan, aspartic acid; glutamic acid, arginine, lysine, histidine, a transition metal.

The total amount of pigment precursors, one or more, is preferably 0.5 to 80% by weight, particularly preferably 10 to 70% by weight, especially preferably 25 to 60% by weight, based on the weight of the printing substance, depending on the type of pigment precursors and the desired opacity.

In a particularly preferred embodiment, it can be provided that the amount of pigment precursors, one or more, in total is preferably 0.5 to 95% by weight, particularly preferably 10 to 85% by weight, particularly preferably 25 to 60% by weight. % based on the weight of the printing substance, depending on the nature of the pigment precursors and the opacity desired.

In addition to one or more pigment precursors, it can be provided that the printing substance comprises at least one network former preliminary compound and/or network converter preliminary compound, the printing substance preferably having at least one network former preliminary compound, particularly preferably a mixture of network former preliminary compound and network converter preliminary compound. Here, the network-former pre-connection can be used as an individual component or as a mixture of two, three or more network-former pre-connections. Furthermore, the network converter pre-connection can be used as a single component or as a mixture of two, three or more network converter pre-connections. The terms "network former" and "network modifier" are widely known in the art, the expressions "network former pre-compound" and "network modifier pre-compound" being based thereon and a pre-compound, also called precursor, is a compound that can be converted into a desired substance, so that a network former connection can be converted into a network former by appropriate reactions. The same applies to the other terms, such as “pigment pre-connection” and “network converter pre-connection”.

An inorganic network is preferably formed by the network-forming precursor compound contained in the printing substance, which network can particularly preferably be formed by SiC> ₄ tetrahedrons. The cations that build up such network-forming polyhedra are therefore referred to as network formers, while the cations that break down or change the network are called network modifiers. Network formers include Si, Ge, B, Bi, Sb, As and P, network modifiers include the alkalis and alkaline earths. Al ₂ O ₃ , T1O ₂ , SnC> ₂ , ZrC> ₂ , MgO can partly replace the S1O ₂ in the glass structure, in this case they act as network formers. If they don't, they act as network converters.

It can preferably be provided that the network former compound comprises at least one silicon compound, a boron compound and/or a bismuth compound.

Furthermore, it can be provided that the network former compound comprises at least one silicon compound, preferably an alkoxysilane. Bevorzugte Alkoxysilane sind unter anderem Tetraethoxysilan, Tetramethoxysilan, Tetrabutoxysilan, Methyltrimethoxysilan, Methyltriethoxysilan, Methyltriisopropoxysilan, Methyltributoxysilan, Methyltriisopropenoxysilan, Dimethyldimethoxysilan, Dimethyldiethoxysilan, Dimethyldiisopropoxysilan, Dimethyldibutoxysilan, Dimethyldiisopropenoxysilan, Trimethylmethoxysilan, Trimethylethoxysilan, Trimethylisopropenoxysilan, Ethyltrimethoxysilan, Butyltrimethoxysilane, Hexyltrimethoxysilan, Dodecyltrimethoxysilan, Decyltrimethoxysilan, Dodecyltriethoxysilan, Decyltriethoxysilan , phenyltriethoxysilane, phenyltrimethoxysilane, cyclohexyltriethoxysilane, cyclohexyltrimethoxysilane, propylmethyldiethoxysilane, propylmethyldimethoxysilane, hexylmethyldiethoxysilane, hexylmethyldimethoxysilane, phenylmethyldiethoxysilane, phenylmethyldimethoxysilane, diphenyldiethoxysilane, diphenyldimethoxysilane, and dimethylphenylmethoxysilane; and alkoxysilanes that have functional organic groups such as: vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, 5-hexenyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3- (meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane,

3-(meth)acryloxypropylmethyldiethoxysilane, 4-vinylphenyltrimethoxysilane, 3-(4-vinylphenyl)propyltrimethoxysilane, 4-vinylphenylmethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3 -mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropylmethyldiethoxysilane. Boron compounds, such as, for example, boron alkyl esters, preferably trimethyl borate, triethyl borate, triisopropyl borate or tributyl borate or mixtures thereof, can be used as further network former precursor compounds. Preferably, the network former precursor is soluble in an organic solvent. Preferred organic solvents are set out later, with reference to these solvents.

Furthermore, it can be provided that the network converter preliminary compound comprises at least one alkali metal compound and/or alkaline earth compound, preferably a sodium and/or potassium compound, or magnesium, calcium, strontium or barium compound, particularly preferably a potassium compound.

Provision can preferably be made for the network converter preliminary compound to comprise at least one alkali metal compound, preferably a sodium or potassium compound, particularly preferably a potassium compound. Preferred sodium or potassium compounds, or magnesium, calcium, strontium or barium compounds include sodium carboxylates and potassium carboxylates, or magnesium carboxylates, calcium carboxylates, strontium carboxylates and barium carboxylates. The preferred carboxylates, which particularly preferably have the formula (CHsC _n Fh _n COO- with n = 0 - 18) include, inter alia, decanoate, neodecanoate, 2-ethylhexanoate, cyclohexanoate, acrylates, oleates, benzoates. Furthermore, dicarboxylic acids can be used to form the complexes and/or salts, which particularly preferably correspond to the formula (HOOCCnFhnCOOH with n=0-10), such as oxalic acid, malonic acid, or sebacic acid, maleic acid or fumaric acid. Furthermore, as a ligand and / or salt component, hydroxycarboxylates such as derivatives of glycolic acid, lactic acid, malic acid, mandelic acid, tartaric acid, citric acid, and / or ketocarboxylates such as salts / complexes of glyoxylic acid, pyruvic acid, acetoacetic acid or ethyl acetoacetate and / or amino carboxylates such as salts/complexes of amino acids such as glycine, alanine, valine, leucine, isoleucine, phenylalanine, tyrosine, proline, hydroxyproline, serine, threonine, cysteine, cystine, methionine, tryptophan, aspartic acid; Glutamic acid, arginine, lysine, histidine can be used.

Another object of the present invention is a printing substance for carrying out a method according to the present invention, wherein the printing substance comprises at least one network former precursor and network modifier precursor and at least one pigment precursor which is soluble in an organic solvent, and the pigment precursor comprises at least one transition metal, wherein the transition metal contained in the pigment precursor is selected from cobalt, iron, chromium, copper, manganese and the network former precursor comprises at least one silicon compound, boron compound and/or bismuth compound and the network modifier precursor comprises at least one alkali metal compound.

Surprising advantages can be achieved in that the molar ratio of network former compound, based on silicon, boron and/or bismuth, to the sum of the alkali metal/alkaline earth metal compound, based on the alkali metal or Alkaline earth metal is in the range of 120:1 to 1:140, preferably 12:1 to 1:14, more preferably in the range of 6:1 to 1:7.

Preferred network former precursors, network modifier precursors and pigment precursors have been set forth above, and reference is made to such network former precursors, network modifier precursors and pigment precursors to avoid repetition.

Preferably the network modifier precursor is soluble in an organic solvent. Preferred organic solvents are set out later, with reference to these solvents.

Surprising advantages can be achieved in that the network former pre-compound at least one silicon compound and the network modifier pre-compound at least one alkali metal compound and / or alkaline earth metal compound and the molar ratio of silicon compound, based on silicon, to the sum of the alkali / alkaline earth metal compound based on the alkali metal or alkaline earth metal in the range from 150:1 to 1:2, preferably from 12:1 to 1:1, more preferably in the range from 9:1 to 1:1.

Further surprising advantages can be achieved in that the network former pre-compound comprises at least one silicon compound and the network modifier pre-compound comprises at least one alkali metal compound and/or alkaline earth metal compound and the molar ratio of silicon compound, based on silicon, to the sum of the alkali metal/alkaline earth metal compound based on the alkali metal or alkaline earth metal range of 100:1 to 1:150, preferably 5:1 to 1:24, more preferably in the range of 3:2 to 1:12.

Furthermore, surprising advantages can be achieved in that the network former compound comprises at least one silicon compound and boron compound. Advantageously, it can be provided that the molar ratio of silicon compound, based on silicon, to boron compound, based on boron im The range is from 150:1 to 1:200, preferably from 12:1 to 1:25, more preferably in the range from 2:1 to 1:12.

Furthermore, it can be provided that the molar ratio of pigment precursor to network-former precursor is in the range from 600:1 to 1:2, preferably 30:1 to 1:1, particularly preferably in the range from 10:1 to 3:2.

In addition, it can be provided that the molar ratio of pigment precursor to network-former precursor is in the range from 600:1 to 1:2, preferably 30:1 to 2:3, particularly preferably in the range from 15:1 to 1:1.

Furthermore, it can be provided that the molar ratio of pigment precursor to network-former precursor is in the range from 600:1 to 1:2, preferably 30:1 to 1:1, particularly preferably in the range from 20:1 to 5:1.

Furthermore, it can be provided that the molar ratio of pigment precursor to network modifier precursor is in the range from 600:1 to 1:2, preferably 30:1 to 1:1, particularly preferably in the range from 22:1 to 3:2.

The network former pre-connection and/or network converter pre-connection preferably form a glass matrix, as is known from the prior art, which is exemplified above. In this case, the glass matrix is of an inorganic nature and is particularly preferably based on SiC>2. The glass matrix acts like an adhesion promoter or adhesion enhancer between the substrate and the pigment.

In general, a printing substance according to the invention can contain binders and other customary additives. These include, inter alia, defoamers, neutralizing agents, leveling agents, wetting agents, rheological additives and/or stabilizers. Defoamers, neutralizing agents, leveling agents, wetting agents, dispersants, rheological additives and/or stabilizers are preferably used in an amount of 0 to 50% by weight, particularly preferably 0.1 to 30% by weight and especially preferably 1 to 20% by weight. , based on the total mass of the printing substance. Defoamers can, for example, consist of modified acrylates or modified acrylate copolymers, but also, and preferably, of silicone-containing ones Connections selected. Leveling agents include, for example, modified polyacrylates and polysiloxanes.

Particularly preferred additives are homogenizing agents, which are used in particular in systems containing Co and/or Cu. They can also act as ligands here, since a color change from blue to violet is sometimes observed in systems containing Co, which is an indication of this. It can therefore be provided that the printing substance comprises a homogenizing agent, preferably an amine compound, particularly preferably ethanolamine, diethanolamine, triethanolamine and/or 2-amino-2-methyl-1-propanol. The proportion by weight of the homogenizing agent in the printing substance is preferably in the range from 0 to 40% by weight, particularly preferably in the range from 1.5 to 20% by weight.

The binders can be cellulose, cellulose derivatives, poly(meth)acrylates, polyvinyl alcoholates, polyvinyl pyrolidones, polyvinyl acetates, polyamides, polyurethanes and derivatives of these, as well as hydrocarbon resins, maleic acid resins, styrene resins, colophony resins, phenolic resins and combinations of these.

Particularly preferred binders are alkyl celluloses and hydroxyalkyl celluloses such as ethyl cellulose and hydroxypropyl cellulose.

Furthermore, the printing substance can contain organic solvents. As a result, the workability can be improved. Organic solvents are compounds containing carbon and hydrogen atoms that are removed from the coating after the printing substance is applied. This can be done by burning, i.e. heating the printed substrate to the temperatures set out above for the conversion of the pigment precursor into pigment particles, which are preferably in the range from 400° C. to 1000° C., preferably 550° C. to 750° C., particularly preferably 620 °C to 700 °C, especially preferably 650 °C to 690 °C.

Furthermore, it can be provided that the printing substance comprises a solvent, the solvent preferably being selected from glycols, glycol ethers, glycol acetates, terpineol, alcohols, water, ketones, esters, diacetone alcohol, Alkanolamines, aromatic hydrocarbons, aliphatic hydrocarbons and/or alkanoic acids and sulfonic acids. The pigment precursor and the are particularly preferred

Network converter pre-connection soluble in the solvent used, all of the components mentioned being particularly preferably soluble in the solvent used.

Furthermore, it can be provided that the proportion by weight of the solvent in the printing substance is in the range from 5 to 50% by weight, preferably 10 to 40% by weight, particularly preferably 7 to 40% by weight.

Furthermore, it can be provided that the pressure substance has a viscosity in the range of 3 mPas-20 Pas at a shear rate of 200 s-1 and 23° C., measured according to cone/plate 2°20.

In one embodiment, the printing substance is suitable for inkjet printing processes (inkjet processes). It can therefore be provided that the printing substance, preferably the ink, has a viscosity in the range from 3 mPas to 100 mPas at a shear rate of 600 s ¹ and 23° C., measured with a cone/plate (2°20) on a rotational viscometer.

In a preferred embodiment, the printing substance is suitable for screen printing processes. It can therefore be provided that the pressure substance has a viscosity in the range from 1.5 to 20 Pas at a shear rate of 200 s ¹ and 23° C., measured with a cone/plate (2°20) on a rotational viscometer.

Another object of the present invention is a coated glass substrate obtainable by a method according to the present invention, wherein the glass coating in the fired state has a thickness in the range from 0.6 μm to 8 μm, preferably in the range from 0.8 to 4.0 μm and more preferably in the range of 1.0 to 3.0 µm.

Surprisingly, due to the small thickness of the glass coating, an improvement in the transverse rupture strength of the coated glass is achieved, so that this compared to the flexural strength of the pure substrate only leads to a slight reduction in the same.

Furthermore, it can be provided that the coating of the glass substrate comprises pigment particles, the pigment particles preferably having an average particle diameter in the range from 0.05 μm to 0.8 μm, preferably 0.08 μm to 0, inter alia in the case of systems containing Co. 6 µm, particularly preferably 0.1 to 0.5 µm, the average size being determined from the numerical mean of scanning electron micrographs using at least 20 pigment particles. In general, the pigments are visible as bright spots in the SEM, without this being intended to be a limitation. Corresponding values apply to other pigment systems, although these should have a similar opacity.

Furthermore, it can be provided that the part of the glass substrate provided with a coating has an optical density of at least 1.0, preferably at least 2.0, particularly preferably at least 3.0, measured using a transmission densitometer, the measurement being taken at room temperature (20°C ) be performed. For example, the optical density can be measured using a Gretag D 200-11 transmission densitometer.

Glass substrates and coated glass substrates are exposed to different loads, so they are selected depending on the application. The resilience required for this is defined by corresponding standards or requirements of the buyer. The present coatings are preferably made and their components selected to meet these requirements and standards.

Furthermore, it can be provided that the coated glass substrate has a high acid resistance, so that wetting with an acid or base over a period of 5 minutes leads to at most a slight, preferably no significant, change in the coating (20° C.). The coating is particularly resistant to 10% by weight hydrochloric acid, 0.1N sulfuric acid, 10% by weight citric acid, 10% by weight acetic acid and/or 10% by weight sodium hydroxide solution. Furthermore, it can be provided that the coated glass substrate has an average flexural strength of at least 100 N/mm ² , preferably 130 N/mm ² , measured using the ring fracture test, which is presented as an example in the examples. These values relate to a board thickness of 1.9 mm. Thicker plates have correspondingly higher values, thinner plates have correspondingly lower values. A standard automotive glass paint such as 14510 from Ferro showed an average value of 75 N/mm ² on 1.9 mm thick glass plates.

Furthermore, it can be provided that the coating of the glass substrate has a scratch resistance of at least 5 N, preferably at least 20 N, measured with a scratch hardening pencil model 318 with rollers 1.0 tip from Erichsen.

The color of the coating applied to the glass substrate is not particularly limited and can be selected according to requirements. To protect adhesives that are used, for example, in the processing or installation of the coated glass substrate in an automobile, it is advantageous to choose dark colors that absorb as much light as possible. Provision can therefore preferably be made for the coating of the glass substrate to be black.

The color values are preferably measured using an X-Rite Model SP 964 colorimeter. The color measurement is based on DIN 5033 with a reflection spectrophotometer with circular illumination of 0° and an observation angle of 45°. The device measures the spectral reflectance within a range of 400 - 700 nm and calculates the colorimetric data. The color difference between the reference and the sample is calculated in accordance with DIN 6174.

Furthermore, it can be provided that the color values for L* < 15, a* between -5 and +6, b* between -4 and +5, preferably for L* < 14, a* between -4 and +4, b* between -3 and +3, particularly preferably when L* <8, a* between -4 and +4, b* between -3 and +3, particularly preferably L*<5, a* is between -1 and +1 and b* is between -1.7 and +1.5.

The present invention is explained in more detail below with reference to examples, without there being any intention to limit the invention as a result.

test procedure

transverse rupture strength

The transverse rupture strength is determined by the following method. The plates preferably have a size of 10 cm x 10 cm x 1.9 mm.

The glass plates are placed in the flexural fracture measuring apparatus with the colored side down on a silicon pad about 2 mm thick. This is on a 2 mm high metal ring. The ring is slightly smaller in diameter than the plates. A metal rod then presses down on the glass side of the plate with slowly increasing force until it breaks. The bending strength S is calculated from the required force F and the thickness of the glass plate using the formula

1.04s — ^{x F}

The transverse rupture strength must be determined on several panels, since individual panels could show previous damage, which would falsify the result. In fact, as a rule, there is a clear scattering of the values. You should measure about 20 samples and form the numerical mean in order to be able to make a significant statement.

Optical density

The optical density is measured using a Gretag D 200-11 transmission densitometer.

Acid and base resistance To test the chemical resistance of the glass colors, a drop of diluted acid or lye is placed on the finished color coating and this is only washed off again after 5 minutes. The solutions used are sulfuric acid 0.1 N hydrochloric acid 10%

citric acid 10%

acetic acid 10%

caustic soda 10%

The acid and alkali resistance of the color coatings is categorized as follows:

1 = no attack

2 = iridescence of the surface or just noticeable loss of gloss

S = clear matting without deeper color or surface changes

4 = deeper color or surface change or no longer scratch-resistant

5 = Coating removed, substrate is completely or partially exposed

scratch hardness

To determine the scratch hardness, an Erichsen hardness test rod, on which the compressive force can be set in Newton, is scratched onto the glass plates before and after the firing process. A metal spring in the test rod is set to the desired spring force with a slider. A few centimeters long scratch can then be drawn by hand with the tip of the rod on the surface to be examined. The maximum adjustable spring force of the hardness tester is 20 Newton.

The scratch hardness is the force from which the scratch can no longer be seen from the back of the glass plate.

The printing substances set out in the following tables are produced by mixing: example 1

Triethanolamine improves the homogenization of the components, which is carried out in a DISPERMAT type stirrer (5 min at approx. 1500-2000 rpm). AT45 (from Ferro) is a printing medium that is commonly used in the printing ink industry to set viscosity values suitable for screen printing.

To determine the flexural strength, glass plates measuring 10 cm x 10 cm x 2 mm are machine printed with a 90 nylon screen. The oven is preheated to around 300 °C and all the printed glass plates are placed in it. The furnace is then ramped up to 650 °C at maximum power and switched off after a holding time of 7 minutes. The glass plates are removed after a few hours as soon as their temperature is below approx. 200 °C. Otherwise, the glass plates are usually placed in the hot oven between 550° and 750°C, fired for 1 - 5 minutes and then taken out of the oven and cooled in the air.

The flexural strength is 145 +/-49 N/mm ² and is therefore in the range of 140 +/-42 N/mm ² for the unprinted panels. The coating has a high acid and base resistance. A rating of 1 (= no attack) is given for the acids and bases presented.

The scratch hardness is at least 20 N (upper measurement limit)

The optical density is: 2.05

example 2

The coating is printed with a 90T screen and then dried at 120°C for 20 minutes. The subsequent firing takes place at a temperature of 675° C. for 3 minutes, with a coating thickness of 1-2 mm being obtained. FIG. 1 shows a cross-section of an electron micrograph, from which the thickness can be seen. The coating is examined by electron microscopy, where the formation of pigment particles can be seen. This recording is shown in FIG. The optical density is: 2.39.

If the baked layer is printed again with a 90T screen, dried again at 120° C. for 20 minutes and then the glass plate is baked again for 3 minutes 675° C., a layer thickness of 2.5-3 mm is obtained, as can be seen in an electron micrograph, FIG. The further formation of pigment particles can also be observed in FIG. 4 by means of electron microscopy. The optical density is: 4.36.

Example 3

The coating is printed with a 61T screen and then dried at 130°C for 15 minutes. The subsequent firing takes place at a temperature of 670°C for 3 minutes.

The coating has a high acid and base resistance. A rating of 1 (= no attack) is given for the acids and bases presented above.

The optical density is 3.61.

The L* value was 13.26, the a* value -3.30 and the b* value +2.05.

The scratch hardness is 10 N.

FIG. 5 shows a cross section of an electron micrograph showing the thickness. The coating is visualized using electron microscopy examined, whereby the formation of pigment particles is visible. This recording is shown in FIG.

Example 4:

The preparation is applied with a 12 μm spiral squeegee and then fired at 675° C. for 3 minutes. The optical density is: 1.1.

Chemical resistance shows a rating of 1 (no attack).

The L* value was 4.56, the a* value -0.41 and the b* value -1.60.

The scratch hardness is 10 N.

FIG. 7 shows a cross section of an electron micrograph showing the thickness. Figure 8 shows the surface of the coating.

Example 5:

The preparation is applied with a 12 μm spiral squeegee and then fired at 675° C. for 3 minutes. The optical density is: 1.3. Example 6:

The optical density is: 1.2.

The L* value was 4.83, the a* value was +5.19 and the b* value was +4.32.

The scratch hardness is 10 N.

Comparative example 1

Printed all over, a ferrous product GSGA Black 14510 IR-9864-C that is on the market reduces the flexural strength to just S = 75 +/- 17 N/mm ² . The coating is obtained with the same printing and firing procedure as carried out in Example 1.

Example 7:

The coating is printed with a 77T screen and then dried at 130°C for 15 minutes. The subsequent firing takes place at a temperature of 670°C for 3 minutes.

FIG. 9 shows a cross-section of an electron micrograph, from which the thickness of about 1.7 μm can be seen. The coating is examined by electron microscopy, where the formation of pigment particles can be seen. This recording is set forth in FIG.

The optical density is: 2.91.

The L* value was 6.59, the a* value was -1.57 and the b* value was +1.39.

The scratch hardness is > 20N. Example 8:

FIG. 11 shows a cross-section of an electron micrograph, from which the thickness of about 2.3 μm can be seen. The coating is examined by electron microscopy, where the formation of pigment particles can be seen. This recording is set forth in FIG.

The optical density is: 4.37.

The L* value was 7.72, the a* value was +1.20 and the b* value was +2.63.

The scratch hardness is > 20N. Example 9:

FIG. 13 shows a cross-section of an electron micrograph, from which the thickness of about 1.5 μm can be seen. The coating is examined by electron microscopy, where the formation of pigment particles can be seen. This recording is set forth in FIG.

The optical density is: 3.11.

The L* value was 4.25, the a* value -1.04 and the b* value +1.18.

The scratch hardness is > 20N.

The examples show that the objects set out above are achieved by the present invention, in particular the transverse rupture strength of a through the Surprisingly, the decor obtained with the printing substance according to the invention can be significantly increased without other properties of the printing substance or of the decoration being adversely affected as a result.

Claims

Bl patent claims

1. Coated glass substrate, wherein the coating comprises an inorganic glass matrix and pigment particles, characterized in that the coating in the burned-out state has a thickness in the range from 0.6 mm to 8 mm and the color values of the coating in the range for L* < 15, for a* between -5 and +6, for b* between -4 and +5.

2. Coated glass substrate according to claim 1, characterized in that the part of the glass substrate provided with a coating has an optical density of at least 1.0, preferably at least 2.0, particularly preferably at least 3.0.

3. Coated glass substrate according to claim 1 or 2, characterized in that the coating of the glass substrate comprises pigment particles, the pigment particles having an average particle diameter in the range from 0.05 μm to 0.8 μm, preferably 0.08 μm to 0.8 μm , particularly preferably 0.1 to 0.5 μm, the average size being determined from the numerical mean of scanning electron micrographs using at least 20 pigment particles.

4. Coated glass substrate according to at least one of the preceding claims 1 to 3, characterized in that the coating of the glass substrate has a scratch resistance of at least 5 N, measured with a scratch hardening pin model 318 with rollers 1.0 tip from Erichsen.

5. Coated glass substrate according to at least one of the preceding claims 1 to 4, characterized in that the glass substrate is selected from a front window, a side window, a rear window and/or a roof window of a motor vehicle.

6. Coated glass substrate according to at least one of the preceding claims 1 to 5, characterized in that the glass substrate is coated only on a part of the glass surface.

7. Coated glass substrate according to at least one of the preceding claims 1 to 6, characterized in that the coating has a thickness in the range from 1.0 to 3.0 μm in the burned-out state.

8. Coated glass substrate according to at least one of the preceding claims 1 to 7, characterized in that the color values of the coating applied to the glass substrate are in the range for L*<5, for a* between -1 and +1 and for b* between -1, 7 and +1.5 lie.

9. Coated glass substrate according to at least one of the preceding claims 1 to 8, characterized in that the coating applied to the glass substrate does not completely cover the glass substrate, preferably the coating applied to the glass substrate covers the edge of the glass substrate, the edge covered by the coating preferably has a width in the range 0.5 cm to 20 cm, preferably in the range 0.5 cm to 5 cm, and the glass substrate has an inner uncoated area surrounded by the rim.

10. Coated glass substrate according to at least one of the preceding claims 1 to 9, characterized in that at least one network former pre-connection and/or at least one network converter pre-connection form a glass matrix.

11. A method for producing a coated glass substrate according to at least one of the preceding claims 1 to 10 with a printing process in which one

12. The method according to claim 11, characterized in that the heating step involves firing the coated glass surface to a temperature in the range from 400°C to 1000°C, preferably from 550°C to 750°C, particularly preferably 620°C to 700°C, particularly preferably 650°C to 690°C.

13. The method according to claim 11 or 12, characterized in that the heating step is carried out over a period of 1 minute to 180 minutes, preferably 1 to 20 minutes, particularly preferably 1 to 5 minutes.

14. The method according to at least one of the preceding claims 11 to 13, characterized in that the

Printing substance comprises at least one network former precursor and/or network modifier precursor and at least one pigment precursor which is soluble in an organic solvent, and the pigment precursor comprises at least one transition metal.

15. The method according to at least one of the preceding claims 11 to 14, characterized in that the transition metal contained in the pigment precursor is selected from cobalt, iron, nickel, manganese, chromium, copper, aluminum, titanium, molybdenum, preferably cobalt, iron, chromium , copper, manganese, particularly preferably cobalt or iron, particularly preferably cobalt alone or a mixture of iron and cobalt or a mixture of copper and cobalt.

16. The method according to at least one of the preceding claims 11 to 14, characterized in that the transition metal contained in the pigment precursor is selected from iron, nickel, manganese, chromium, copper, aluminum, titanium, molybdenum, ruthenium, preferably iron, chromium, copper , Manganese, particularly preferably manganese, iron and copper or copper, chromium, iron or copper, manganese, iron or copper and manganese.

17. The method according to at least one of the preceding claims 11 to 16, characterized in that the network former compound comprises at least one silicon compound, a boron compound and/or bismuth compound, preferably an alkoxysilane.

18. The method according to at least one of the preceding claims 11 to 17, characterized in that the network modifier precursor comprises at least one alkali metal compound, preferably a sodium or potassium compound, particularly preferably a potassium compound.

19. Printing substance for carrying out a method according to at least one of the preceding claims 11 to 18, characterized in that the printing substance comprises at least one network former precursor and network modifier precursor and at least one pigment precursor which is soluble in an organic solvent, and the pigment precursor comprises at least one transition metal, wherein the transition metal contained in the pigment precursor is selected from cobalt, iron, chromium, copper, manganese and the network former precursor comprises at least one silicon compound, boron compound and/or bismuth compound and the network modifier precursor comprises at least one alkali metal compound

20. Printing substance according to claim 19, characterized in that the molar ratio of network former compound, based on silicon, boron and/or bismuth, to the sum of the alkali metal/alkaline earth metal compound, based on the alkali metal or alkaline earth metal, is in the range from 120:1 to 1:140. preferably 12:1 to 1:14, more preferably in the range 6:1 to 1:7.

21. Printing substance according to claim 19 or 20, characterized in that the molar ratio of pigment precursor to network former precursor is in the range from 600:1 to 1:2, preferably 30:1 to 2:3, particularly preferably in the range from 15:1 to 1: 1 lies.

22. Printing substance according to at least one of the preceding claims 19 to 21, characterized in that the printing substance comprises a homogenizing agent, preferably an amine compound, particularly preferably ethanolamine, diethanolamine, triethanolamine and/or 2-amino-2-methyl-1-propanol.

23. Printing substance according to at least one of the preceding claims 19 to 22, characterized in that the printing substance comprises a solvent, the solvent preferably being selected from glycols, glycol ethers, glycol acetates, terpineol, alcohols, water, ketones, esters, diacetone alcohol, alkanolamines, aromatic hydrocarbons, aliphatic hydrocarbons and/or alkanoic acids and sulfonic acids.

24. Printing substance according to at least one of the preceding claims 19 to 23, characterized in that the printing substance has a viscosity in the range of 3 mPas - 20 Pas at a shear of 200 s-1 and 23°C, measured according to cone/plate 2° 20

25. Coated glass substrate obtainable by a method according to at least one of the preceding claims 11 to 18, characterized in that the glass coating in the fired state has a thickness in the range from 0.6 μm to 8 μm, preferably in the range from 0.8 to 4 0 μm and particularly preferably in the range from 1.0 to 3.0 μm.