Substrate element for coating with an easy-to-clean coating

Substrate element for coating with an easy-to-clean coating

description

The invention relates to a substrate element for coating with an easy-to-clean coating, which comprises a carrier plate and an adhesive layer arranged on the carrier plate, which is suitable for interacting with an easy-to-clean coating. The invention further relates to a method for producing such a substrate element and the use of such a substrate element.

The coating of surfaces, in particular of a transparent material such as glass or glass ceramic, is becoming increasingly important, not least because of the rapidly growing market for touch screens or touch screens, for example in the area of ​​touch panel applications with interactive input. Here, the touch surfaces must meet the requirements of transparency and functionality, which are becoming ever higher, for example in the area of ​​multi-touch applications. Touchscreens are used, for example, to operate smartphones, ATMs or as information monitors, such as for information on timetables at train stations. In addition, touchscreens are also used, for example, in gaming machines or for the control of machines in industry (industrial PCs). A remuneration for transparent glass or glass ceramic surfaces comes into focus for all cover plates, but in particular also for cover plates of mobile electronic products, such as for displays of notebooks, laptop computers, watches or mobile phones. But surface treatment is also becoming increasingly important for glass or glass ceramic surfaces, for example of refrigerated furniture, shop windows, counters or showcases. All applications are concerned with ensuring good transparency and a high aesthetic effect with good and hygienic functionality without high cleaning effort, which is impaired, for example, by dirt and residues from fingerprints.

A surface coating is an etching of the glass surface, as is known, for example, with anti-glare panes, such as the Antiglare screens. A disadvantage here, however, is a high loss of transparency and image resolution, since due to the structured surface, the imaging light from the device to the viewer is refracted and scattered on the display pane. In order to achieve a high image resolution, other solutions are sought in the area of ​​coating the surface with an easy-to-clean coating.

In the foreground of the required properties, the tactile and haptic perceptibility of the touch surface, which should be smooth, especially for multi-touch applications, is particularly important for touchscreens. What matters here is what can be felt by the user, less what is measurable roughness. The focus is also on high transparency with low reflectivity, high dirt repellency and ease of cleaning, above all long-term durability of the easy-to-clean coating after use and many cleaning cycles, scratch and abrasion resistance, for example when using stylus, resistance to chemical stress caused by finger sweat containing salts and fats as well as the durability of a coating even when exposed to the climate and UV. The easy-to-clean effect ensures that dirt that comes to the surface through the environment or through natural use can be easily removed again or is so designed that the dirt does not stick to the surface. In this case, the easy-to-clean surface has the property that dirt, for example by fingerprints, are largely no longer visible and so the user surface appears clean even without cleaning. As a special case of the easy-to-clean surface, this case is an anti-fingerprint surface. A touch surface must be resistant to water, salt and grease deposits, which occur, for example, from residues of fingerprints when used by users. The wetting properties of a contact surface must be such that the surface is both hydrophobic and oleophobic.

Most of the known easy-to-clean coatings are essentially fluoroorganic compounds with a high contact angle with water. DE 19848591, for example, describes the use of an organofluorine compound of the formula R for producing such a protective layer_rV in the form of a liquid substance system from the organofluorine compound in a carrier liquid, wherein in the formula R_rV, R_f represents an aliphatic hydrocarbon radical which can be partially or completely fluorinated and can be straight-chain, branched-chain or cyclic, the hydrocarbon radical being interrupted by one or more oxygen, nitrogen or sulfur atoms. V stands for a polar or dipolar group which is selected from -COOR, -COR, -COF, -CH₂OR, -OCOR, -CONR₂, -CN, -CONH-NO₂, - CON = C (NH₂)₂, -CH = NOR, -NRCONR₂, -NO₂COR, NO_W, -SO₃R, -OSO₂R, -OH, - SH, = B, -OP (OH)₂, -OPO (OH)₂, -OP (ONH₄)₂, -OPO (ONH₄)₂, -CO-CH = CH₂, in which R in a group V can be identical or different and represents hydrogen, a phenyl radical or a straight-chain or branched-chain alkyl or alkyl ether radical, which can be partially or completely fluorinated or chlorofluorinated, with up to 12, preferably up to 8, carbon atoms and w is 2 or 3, or for -R_v-V- stands. In the formula -R_v-V- is V for the polar or dipolar group previously indicated and R_v for a straight-chain or branched-chain alkylene radical, which can be partially or fully fluorinated or chlorofluorinated, with 1 to 12, preferably up to 8, carbon atoms.

Furthermore, EP 0 844 265 describes a silicon-containing organic fluoropolymer for coating substrate surfaces such as metal, glass and plastic materials in order to have a sufficient and long-lasting antifouling property, sufficient weather resistance, lubricity, non-stick property, water repellency and resistance to oily soiling and give fingerprints. There is also provided a treatment solution for a surface treatment method, which comprises a silicon-containing organic fluoropolymer, a fluorine-containing organic solvent and a silane compound. Nothing has been said about the suitability of a substrate surface for coating with such an organic fluoropolymer.

US 2010/0279068 describes a fluoropolymer or a fluorosilane as an anti-fingerprint coating. In this context, the US already points

2010/0279068 indicates that the coating of a surface alone with such a coating is insufficient to provide the required surface properties for an anti-fingerprint coating. To solve the problem, US 2010/0279068 suggests embossing a structure into the surface of the glass article or pressing it into these particles. Preparing the surface in this way for coating with an anti-fingerprint coating is very complex and costly and, because of the thermal processes required, creates undesirable stresses in the glass articles.

US 2010/0285272 describes an anti-fingerprint coating as a polymer with a low surface tension or an oligomer, such as a fluoropolymer or a fluorosilane. To prepare the surface for coating with an anti-fingerprint coating, it is proposed to sandblast the glass surface and then to apply a metal or metal oxide, such as tin oxide, zinc oxide, cerium oxide, aluminum or zirconium, by means of physical or chemical vapor deposition. To prepare the surface for an anti-fingerprint coating, it is also proposed to etch the sputtered metal oxide film or to anodize the vapor-deposited metal film. A graduated surface structure with two topological levels is to be provided. The anti-fingerprint coating then contains a further graduated topological structure. These processes are also complex and cost-intensive and only lead to a hydrophobic and oleophobic surface with mechanical anchoring of the polymer by the structured surface, without taking sufficient account of the other required properties.

US 2009/0197048 describes an anti-fingerprint or easy-to-clean coating on a cover glass in the form of an outer coating with fluorine end groups, such as perfluorocarbon or a residue containing perfluorocarbon, which gives the cover glass a degree of hydrophobicity and oleophobia gives, so that the wetting of the glass surface with water and oils is minimized. For the application of this layer to a glass surface, it is proposed to harden the surface chemically by means of ion exchange, in particular by incorporating potassium ions instead of sodium and / or lithium ions. Furthermore, the cover glass under the anti-fingerprint or easy-to-clean coating can be an anti-reflective layer made of silicon dioxide, quartz glass, fluorine-doped silicon dioxide, fluorine-doped quartz glass, MgF₂, HfO₂, TiO₂, ZrO₂, Y₂O₃ or Gd₂O₃ contain. It is also proposed to produce a texture or a pattern on the glass surface before the anti-fingerprint coating by means of etching, lithography or particle coating. It is also proposed to subject the glass surface to an acid treatment after hardening by means of ion exchange before the anti-fingerprint coating. These processes are also complex and do not lead to an easy-to-clean coating that meets the sum of the required properties.

A particular disadvantage of such prior art easy-to-clean layers is the limited long-term durability of the layers, so that a rapid decrease in the easy-to-clean properties is observed due to chemical and physical attack. This disadvantage depends not only on the type of easy-to-clean coating, but also on the type of substrate surface to which it is applied.

The object of the invention is therefore to provide a substrate element which has a special surface which is suitable for interacting with a large number of easy-to-clean coatings in such a way that the properties of an easy-to-clean coating are improved and the Touch surface has the required properties to a sufficient extent and the manufacture of such a substrate is inexpensive and simple.

The invention solves this problem in a surprisingly simple manner with the features of claim 1, claim 15, claim 20 and claims 22 to 24. Further advantageous refinements of the invention are described in dependent claims 2 to 14, 16 to 19 and 21.

The inventors have found that for an easy-to-clean coating that satisfies all the required properties satisfactorily, a special adhesion promoter layer must be provided on the substrate element to be coated, which is arranged on a carrier substrate, consists of a mixed oxide and has the property to interact with an easy-to-clean coating to be applied later.

The interaction is a chemical, in particular covalent bond between the adhesion promoter layer of the substrate according to the invention and an easy-to-clean coating to be applied later, which acts in such a way that the long-term stability of an easy-to-clean coating is increased. “Easy-to-clean (ETC) coating”, such as, in particular, an “anti-fingerprint (AFP) coating”, is understood to mean a coating which has a high dirt-repellent property, is easy to clean and also has an anti-graffiti effect can. The material surface of such an easy-to-clean coating shows a resistance to deposits, for example fingerprints, such as liquids, salts, greases, dirt and other materials. This relates both to the chemical resistance to such deposits and to a low wetting behavior against such deposits. Furthermore, it relates to the suppression, avoidance or reduction of fingerprints when touched by a user. Fingerprints mainly contain salts, amino acids and fats, substances such as talc, sweat, residues of dead skin cells, cosmetics and lotions and possibly dirt in the form of liquids or particles of all kinds.

Such an easy-to-clean coating must therefore be resistant to both water with salt as well as grease and oil deposits and have a low wetting behavior towards both. Particular attention should be paid to high resistance in a salt water spray test. The wetting characteristics of a surface with an easy-to-clean coating must be such that the surface is both hydrophobic, ie the contact angle between surface and water is greater than 90 ° and is also oleophobic, ie the contact angle between surface and oil is greater than 50 °.

State-of-the-art solutions in particular use the so-called lotus effect to increase the contact angle. This is based on a double structure of the surface, as a result of which the contact area and thus the adhesive force between the surface and particles and water drops lying on it is greatly reduced. This double structure is formed from a characteristically shaped surface structure in the range of approximately 10 to 20 micrometers and an easy-to-clean coating applied to it. The wetting behavior of liquids on solid roughened surfaces can either be described with the Wenzel model for low contact angles or with the Cassie-Baxter model for high contact angles, as described, for example, by US 2010/0285272. In contrast to this structural effect, the invention achieves the object in a chemically based way.

In a preferred embodiment, the adhesion promoter layer is a liquid phase coating, in particular a thermally solidified sol-gel layer. However, the adhesion promoter layer can also be a CVD coating (layer application by plasma-assisted chemical vapor deposition), which is produced, for example, by means of PECVD, PICVD, low-pressure CVD or chemical vapor deposition at atmospheric pressure. The adhesion promoter layer can, however, also be a PVD coating (layer application by plasma-assisted physical vapor deposition), which is produced, for example, by means of sputtering, thermal evaporation, laser beam, electron beam or arc evaporation. The adhesion promoter layer can also be a flame pyrolysis layer.

In a preferred embodiment, the adhesion promoter layer is a silicon mixed oxide layer, the admixture preferably being an oxide of at least one of the elements aluminum, tin, magnesium, phosphorus, cerium, zirconium, titanium, cesium, barium, strontium, niobium, zinc, boron and / or Magnesium fluoride, preferably containing at least one oxide of the element aluminum. In the case of a silicon-aluminum mixed oxide layer, the molar ratio of aluminum to silicon in the mixed oxide is between approximately 3% to approximately 30%, preferably between approximately 5% and approximately 20%, particularly preferably between approximately 7% and approximately 12%. For the purposes of this invention, silicon oxide is understood to mean any silicon oxide between silicon mono- and silicon dioxide. Silicon in the sense of the invention is understood as metal and as semimetal. Mixed silicon oxide is a mixture of a silicon oxide with an oxide of at least one other element, which can be homogeneous or non-homogeneous, stoichiometric or non-stoichiometric.

Such an adhesion promoter layer has a layer thickness of greater than 1 nm, preferably greater than 10 nm, particularly preferably greater than 20 nm. It is important here that, taking into account the depth of the interaction with the easy-to-clean coating, the adhesion promoter function of the layer can be fully utilized.

Such an adhesion promoter layer has a refractive index in the range from 1.35 to 1.7, preferably in the range from 1.35 to 1.6, particularly preferably in the range from 1.35 to 1.56 (at 588 nm reference wavelength).

The adhesion promoter layer according to the invention can preferably be applied using a sol-gel method or else using a method with chemical or physical vapor deposition, in particular by sputtering.

It is a great advantage of the invention that, if the substrate consists of glass or comprises glass, it can also be thermally tempered after the coating and thus thermally hardened without the coating being significantly damaged. Thermal curing is preferably carried out in that at least the area of ​​the glass to be hardened, depending on the glass thickness, is preferably heated to a temperature of about 600 ° C. to about 750 ° C. for a period of, for example, about 2 minutes to 6 minutes, preferably 4 minutes is brought to a temperature of about 670 ° C. Another great advantage of the invention lies in the fact that when the adhesive-thickener layer is produced by a liquid phase coating, in particular by a sol-gel coating, the thermal consolidation of the coating can take place in situ with a thermal prestressing of the carrier material. This includes inexpensive manufacture.

If the surface of the carrier material is activated before the application of the adhesion promoter layer, in particular as a sol-gel layer, this can improve the adhesiveness of the applied layer. The treatment can advantageously be carried out by a washing process or as activation by corona discharge, flame treatment, UV treatment, plasma activation and / or mechanical processes such as roughening, sandblasting and / or chemical processes such as etching.

In one embodiment, at least one barrier layer is arranged between the anti-reflective layer and the carrier material, the barrier layer being in particular in the form of an alkali barrier layer, in particular in the form of a sodium barrier layer. The thickness of such a barrier layer is in the range between 3 and 100 nm, preferably between 5 and 50 nm and particularly preferably between 10 and 35 nm. The barrier layer preferably comprises a metal and / or semimetal oxide. In particular, a barrier layer is essentially formed from silicon oxide and / or titanium oxide and / or tin oxide. Such a barrier layer is applied by means of flame pyrolysis, a physical (PVD) process or a chemical vapor deposition (CVD) process, or else using a sol-gel process. Such a barrier layer is preferably essentially designed as a glass layer. Another component of the invention is an adhesion promoter layer which is divided into partial layers by one or more very thin intermediate layers. This serves above all to avoid stress within the bonding agent layer. For example, it can be divided by one or more pure silicon oxide intermediate layers. The thickness of such an intermediate layer is 0.3 to 10 nm, preferably 1 to 3 nm, particularly preferably 1.5 to 2.5 nm.

In one embodiment, the adhesion promoter layer can be provided with a cover layer. Such a cover layer must be designed in such a way that an interaction between the adhesion promoter layer and an easy-to-clean layer, ie a chemical, in particular covalent, bond between the adhesion promoter layer and an easy-to-clean coating to be applied later is sufficiently possible . Such layers are, for example, porous sol-gel layers or thin, partially permeable flame-pyrolytically applied oxide layers. It can also provide a supportive structure for the easy-to-clean coating that can be applied later. Such a cover layer can be designed as a particulate or porous layer. In particular, it is advantageous to produce such a cover layer from silicon oxide, the silicon oxide also being a silicon mixed oxide, in particular one with an oxide of at least one of the elements aluminum, tin, magnesium, phosphorus, cerium, zirconium, titanium, cesium, barium, strontium, niobium , Zinc, boron or silicon oxide mixed with magnesium fluoride. A flame-pyrolytic coating, other thermal coating processes, cold gas spraying or, for example, sputtering, for example, are suitable for producing such a cover layer.

In principle, all suitable materials are suitable as carrier material for applying an adhesion promoter layer according to the invention, such as a metal, a plastic, a crystal, a ceramic or a composite material. However, a glass or a glass ceramic is preferred. A glass that is toughened for its use is particularly preferably used here. This glass can be chemically toughened by ion exchange or thermally toughened. In particular, low-iron soda-lime glasses, borosilicate glasses, aluminosilicate glasses, lithium aluminum silicate glasses and glass ceramics are preferred, which are obtained, for example, by means of drawing processes such as updraw or downdrawing processes, overflow fusion, float technology or from a cast or rolled glass. Especially in the case of the casting or rolling process or a floated glass, it may be that the necessary optical quality of the surface, which is required, for example, for a display front pane, can be achieved via a polishing technology.

Low-iron or iron-free glass, in particular with an Fe, can be advantageous₂O₃Content of less than 0.05% by weight, preferably less than 0.03% by weight, because this has reduced absorption and thus in particular enables increased transparency.

Gray glasses or colored glasses are also preferred for other applications. The carrier materials, in particular glasses, can be transparent, translucent or even opaque. For example, for use as a "White

Boards ", the use of a milky-looking glass is preferred, as is the Schott AG, Mainz under Opalika^® offers.

Excellent optical properties in the ultraviolet spectral range can be achieved if the carrier material is quartz glass. An optical glass can also serve as the carrier material, such as, for example, a heavy flint glass, lanthanum heavy flint glass, flint glass, light flint glass, crown glass, borosilicate crown glass, barium crown glass, heavy crown glass or fluor crown glass.

Lithium aluminum silicate glasses of the following glass compositions are preferably used as the carrier material, consisting of (in% by weight) SiO₂ 55-69

AI₂O₃ 19-25

Li₂O 3-5

Sum na₂O + K₂O 0-3

Total MgO + CaO + SrO + BaO: 0-5

ZnO 0-4

TiO₂ 0-5

ZrO₂ 0-3

Total TiO₂+ ZrO₂+ SnO₂ 2-6

P₂O₅ 0-8

F 0-1

B₂O₃ 0-2 ,

and optionally additions of coloring oxides, such as Nd₂O₃, Fe₂O₃, CoO, NiO, V₂O₅, Nd₂O₃, MnO2, TiO2, CuO, CeO2, Cr₂O₃, Rare earth oxides in contents of 0-1% by weight, as well as refining agents such as As₂O₃, Sb₂O₃, SnO₂, SO₃, Cl, F, CeO₂ from 0-2% by weight.

Lime-soda-silicate glasses of the following glass compositions are also preferably used as the carrier material, consisting of (in% by weight)

SiO₂ 40-80

AI₂O₃ 0-6

B₂O₃ 0-5

Sum Li₂O + well₂O + K₂O 5-30

Sum MgO + CaO + SrO + BaO + ZnO: 5-30

Total TiO₂+ ZrO₂ 0-7

P₂O₅ 0-2,

and optionally additions of coloring oxides, such as Nd₂O₃, Fe₂O₃, CoO, NiO, V₂O₅, Nd₂O₃, MnO2, TiO2, CuO, CeO2, Cr₂O₃, Rare earth oxides in contents of 0-5% by weight or for "black glass" of 0-15% by weight, as well as refining agents such as As₂O₃, Sb₂O₃, SnO₂, SO₃, Cl, F, CeO₂ from 0-2% by weight. Borosilicate glasses of the following glass compositions are also preferably used as the carrier material, consisting of (in% by weight)

SiO₂ 60-85

AI₂O₃ 1 -10

<img file="WO2012163947A1_D0001.tif" />

Sum Li₂O + well₂O + K₂O 2-16

Total MgO + CaO + SrO + BaO + ZnO: 0-15

Total TiO₂+ ZrO₂ 0-5

P₂O₅ 0-2,

and optionally additions of coloring oxides, such as Nd₂O₃, Fe₂O₃, CoO, NiO, V₂O₅, Nd₂O₃, MnO2, TiO2, CuO, CeO2, Cr₂O₃, Rare earth oxides in contents of 0-5% by weight or for "black glass" of 0-15% by weight, as well as refining agents such as As₂O₃, Sb₂O₃, SnO₂, SO₃, Cl, F, CeO₂ from 0-2% by weight.

Alkali-aluminosilicate glasses of the following glass compositions are also preferably used as the carrier material, consisting of (in% by weight)

SiO₂ 40-75

AI₂O₃ 10-30

B₂O₃ 0-20

Sum Li₂O + well₂O + K₂O 4-30

Total MgO + CaO + SrO + BaO + ZnO: 0-15

Total TiO₂+ ZrO₂ 0-15

P₂O₅ 0-10,

and optionally additions of coloring oxides, such as Nd₂O₃, Fe₂O₃, CoO, NiO, V₂O₅, Nd₂O₃, MnO2, TiO2, CuO, CeO2, Cr₂O₃, Rare earth oxides in contents of 0-5% by weight or for "black glass" of 0-15% by weight, as well as refining agents such as As₂O₃, Sb₂O₃, SnO₂, SO₃, Cl, F, CeO₂ from 0-2% by weight. Alkali-free aluminosilicate glasses of the following glass compositions are also preferably used as the carrier material, consisting of (in% by weight)

SiO₂ 50-75

AI₂O₃ 7-25

<img file="WO2012163947A1_D0002.tif" />

Sum Li₂O + well₂O + K₂O 0.1-0

Total MgO + CaO + SrO + BaO + ZnO: 5-25

Total TiO₂+ ZrO₂ 0-10

P₂O₅ 0-5,

and optionally additions of coloring oxides, such as Nd₂O₃, Fe₂O₃, CoO, NiO, V₂O₅, Nd₂O₃, MnO2, TiO2, CuO, CeO2, Cr₂O₃, Rare earth oxides in contents of 0-5% by weight or for "black glass" of 0-15% by weight, as well as refining agents such as As₂O₃, Sb₂O₃, SnO₂, SO₃, Cl, F, CeO₂ from 0-2% by weight.

Furthermore, low-alkali aluminosilicate glasses of the following glass compositions are preferably used as the carrier material, consisting of (in% by weight)

SiO₂ 50-75

AI₂O₃ 7-25

B₂O₃ 0-20

Sum Li₂O + well₂O + K₂O 0-4

Total MgO + CaO + SrO + BaO + ZnO: 5-25

Total TiO₂+ ZrO₂ 0-10

P₂O₅ 0-5,

and optionally additions of coloring oxides, such as Nd₂O₃, Fe₂O₃, CoO, NiO, V₂O₅, Nd₂O₃, MnO2, TiO2, CuO, CeO2, Cr₂O₃, Rare earth oxides in contents of 0-5% by weight or for "black glass" of 0-15% by weight, as well as refining agents such as As₂O₃, Sb₂O₃, SnO₂, SO₃, Cl, F, CeO₂ from 0-2% by weight.

For applications with display glasses, in particular touch panels or touch screens, of small formats, it is preferred if the substrate has a thickness of &lt;1 mm and in particular is a thin substrate. Thin glasses and thinnest glasses such as those sold by Schott AG, Mainz under the designations D263, B270, Borofloat, Xensation Cover or Xensation cover 3D are particularly preferred. The thinnest glasses have a thickness of 0.02 to 1.3 mm. Thicknesses of 0.03 mm, 0.05 mm, 0.07 mm, 0.1 mm, 0.145 mm, 0.175 mm, 0.21 mm, 0.3 mm, 0.4 mm, 0.55 mm are preferred. 0.7 mm, 0.9 mm, 1, 1 mm, 1, 2 mm or 1, 3 mm.

Is an application for cover panels for displays, as touch panels or touchscreens for larger areas, for example areas with more than 1 m² provided, carrier materials with a thickness of 3 to 6 mm are preferably used, so that a mechanical protective function of the display is also taken over.

The carrier materials can be single disks as well as composite disks. A composite pane comprises, for example, a first and a second pane, which are connected, for example, to a PVB film. At least one surface of the outward-facing surfaces of the composite pane is provided with an adhesion promoter layer according to the invention. The use of direct lamination, for example on the polarizer of a display, is particularly preferred.

The surfaces of the carrier materials can be polished or structured, for example etched, depending on which surface properties are required in order to meet the requirements for good haptics. In one embodiment, the anti-reflective layer can be used in combination with the anti-glare layer. The anti-reflective layer and an easy-to-clean layer applied to it maintain the roughness of the anti-glare layer, while maintaining the ETC or AFP and anti-reflective properties, especially their long-term durability. A partially mirrored or fully mirrored surface is also suitable as a carrier material. This is where the effect of a long-term easy-to-clean or anti-fingerprint coating comes into its own.

Furthermore, the surface of the carrier material can also have a scratch-resistant coating, such as a silicon nitride coating.

Furthermore, a carrier material, in particular the surface of a carrier material, can also have an electrically conductive coating, as is advantageous for various applications, for example in the case of capacitive touch screens. Such coatings are primarily coatings with one or more metal oxides such as ZnO: Al, ZnO: B, ZnO: Ga, ZnO: F, SnO_x: F, SnO_x: Sb and ITO (ln₂O₃: SnO₂). However, one or more thin metal layers can also be applied as a conductive coating on a carrier material, such as aluminum, silver, gold, nickel or chromium.

The invention also relates to a method for producing a substrate for coating with an easy-to-clean coating. Such a procedure comprises the following steps:

First of all, a carrier material, in particular made of a glass or a glass ceramic, is provided. However, a metal, a plastic or any material that meets the requirements of the coating process can also be provided. The surface or surfaces to be coated are cleaned. Cleaning with liquids is a common procedure in connection with glass substrates. Various cleaning liquids are used here, such as demineralized water or aqueous systems such as dilute alkalis (pH&gt; 9) and acids, detergent solutions or non-aqueous solvents such as alcohols or ketones. In a further embodiment of the invention, the carrier material can also be activated before the coating. Such activation processes include oxidation, corona discharge, flame treatment, UV treatment, plasma activation and / or mechanical processes, such as roughening, sandblasting, and plasma treatments or also treatment of the substrate surface to be activated with an acid and / or an alkali.

The adhesion promoter layer is applied by means of a process of physical or chemical vapor deposition, by means of flame pyrolysis or a so-gel process. In the latter case, the adhesion promoter layer can be applied to the surface by dipping, steam coating, spraying, printing, roller application, in a wiping process, a brushing or rolling process and / or a lapping process or another suitable method. Immersion and spraying are preferred.

In the preferred sol-gel process, a reaction of organometallic starting materials in the dissolved state is used for the formation of the layer. A controlled hydrolysis and condensation reaction of the organometallic starting materials builds up a metal oxide network structure, ie a structure in which the metal atoms are connected to one another by oxygen atoms, along with the elimination of reaction products such as alcohol and water. The hydrolysis reaction can be accelerated by adding catalysts.

In a preferred embodiment, the carrier material is pulled out of the solution during the sol-gel coating at a drawing speed of approximately 200 mm / min to approximately 900 mm / min, preferably approximately 300 mm / min, the moisture content of the atmosphere being between approximately 4 g / m3 and about 12 g / m3, particularly preferably about 8 g / m3. If the sol-gel coating solution is to be used or stored for a longer period of time, it is advantageous to stabilize the solution by adding one or more complexing agents. These complexing agents must be soluble in the immersion solution and should advantageously be related to the solvent in the immersion solution. Organic solvents which have complexing properties at the same time, such as methyl acetate, ethyl acetate, acetylacetone, acetoacetic ester, ethyl methyl ketone, acetone and similar compounds, are preferred. These stabilizers are added to the solution in amounts of 1 to 1.5 ml / l.

In a preferred embodiment corresponding to, for example, FIG. 1, in order to produce a substrate element 11, such an adhesion promoter layer 3 is applied by dip coating according to the sol-gel principle. Here, for the production of a silicon mixed oxide layer as an adhesion promoter layer 3 on the at least one surface 20 of the prepared, washed carrier material 2, for. B. a glass pane, dipped in an organic solution containing a hydrolyzable compound of silicon. The carrier material is then pulled out of this solution evenly into an atmosphere containing moisture. The layer thickness of the silicon mixed oxide bonding agent precursor layer which forms is determined via the concentration of the silicon starting compound in the dipping solution and the drawing speed. The layer can be dried after application in order to achieve a higher mechanical strength when transferred to the high-temperature furnace. This drying can take place in a wide temperature range. Typically, drying times of a few minutes are required at temperatures in the range of 200 ° C. Lower temperatures result in longer drying times. It is also possible to go to the thermal solidification step in the high-temperature furnace immediately after the layer has been applied. The drying step serves to mechanically stabilize the coating. The essentially oxidic adhesion promoter layer is formed from the applied gel film in the high-temperature step, in which organic components of the gel are burned out. In this case, the final silicon mixed oxide layer or Mixed oxide layer as bonding agent layer, the bonding agent precursor layer baked at temperatures below the softening temperature of the carrier material, preferably at temperatures below 550 ° C., in particular between 350 and 500 ° C., particularly preferably between 400 and 500 ° C. substrate surface temperature. Depending on the softening temperature of the base glass, temperatures above 550 ° can also be used. However, these do not contribute to further increasing the adhesive strength.

The generation of thin oxide layers from organic solutions has been well known for many years. BH Schröder, Physics of Thin Films 5, Academic Press New York and London (1967, pages 87-141) or US Pat. No. 4,568,578.

The inorganic sol-gel material from which the sol-gel layer is produced is preferably a condensate, in particular comprising one or more hydrolyzable and condensable or condensed silanes and / or metal alkoxides, preferably of Si, Ti, Zr, Al, Nb, Hf and / or Ge. The groups crosslinked in the sol-gel process via inorganic hydrolysis and / or condensation can preferably be, for example, the following functional groups: TiR4, ZrR4, SiR4, AIR3, TiR3 (OR), TiR2 (OR) 2, ZrR2 (OR ) 2, ZrR3 (OR), SiR3 (OR), SiR2 (OR) 2, TiR (OR) 3, ZrR (OR) 3, AIR2 (OR), AIR1 (OR) 2, Ti (OR) 4, Zr ( OR) 4, AI (OR) 3, Si (OR) 4, SiR (OR) 3 and / or Si2 (OR) 6, and / or one of the following substances or groups of substances with OR: Alkoxy such as preferably methoxy, ethoxy, n-propoxy, i-propoxy, butoxy, isopropoxyethoxy, methoxypropoxy, phenoxy, acetoxy, propionyloxy, ethanolamine, diethanolamine, triethanolamine, methacryloxypropyl, acrylate, methacrylate, acetylacetone, ethyl acetate, ethyl acetate , Methoxyacetate, methoxyethoxyacetate and / or methoxyethoxyethoxyacetate, and / or one of the following substances or groups of substances with R: Cl, Br, F, methyl, ethyl, phenyl, n-propyl, butyl, ally, vinyl, glycidylpropyl, methacryloxypropyl, aminopropyl and / or fluoroctyl.

It is common to all sol-gel reactions that molecular-disperse precursors initially react via hydrolysis, condensation and polymerization reactions to form particle-disperse or colloidal systems. Depending on the selected conditions, the "primary particles" that are formed first can continue to grow, aggregate to form clusters or form more linear chains. The units thus created require microstructures that result from the removal of the solvent. In the ideal case, the material can be completely thermally compressed, but in reality often a z. T considerable degree of residual porosity. For this reason, the chemical conditions during the target production have a decisive influence on the properties of a sol-gel coating, as described by P. Löbmann, "Sol-Gel Coatings", training course 2003 "Surface finishing of glass", metallurgical association of the German glass industry .

Si starting materials have been best studied so far, see C. Brinker, G. Scherer, “Sol-Gel-Science - The Physic and Chemistry of Sol-Gel Processing (Academic Press, Boston 1990), R. liier, The Chemistry of Silica (Willey, New York, 1979). The most used Si starting materials are silicon alkoxides in the formula Si (OR) 4, which hydrolyze when water is added. Linear dressings are preferred under acidic conditions. Under basic conditions, the silicon alkoxides react to form more highly crosslinked “globular” particles. The sol-gel coatings contain precondensed particles and clusters. Typically, silicic acid tetraethyl ester or methyl silicate is used as the starting compound for the preparation of a silicon oxide immersion solution B. Ethanol, hydrolysis water and acid as a catalyst are added in the order given and mixed well. For this purpose, mineral acids such as ENT are preferably added to the hydrolysis water₃, HCl, H₂SO₄ or organic acids such as acetic acid, ethoxyacetic acid, methoxyacetic acid, polyether carboxylic acids (eg ethoxyethoxyacetic acid), citric acid, paratoluenesulfonic acid, lactic acid, methyl acrylic acid or acrylic acid.

In a particular embodiment, the hydrolysis is wholly or partly in alkaline, for example using NH₄OH and / or tetramethyl ammonium hydroxide and / or NaOH carried out.

To produce the adhesion promoter layer for the substrate according to the invention, the dipping solution is prepared as follows: The silicon starting compounds are dissolved in an organic solvent. All organic solvents which dissolve the silicon starting compound and which are able to continue to dissolve a sufficient amount of water which is required for hydrolysis of the silicon starting compound can be used as the solvent. Suitable solvents are e.g. As toluene, cyclohexane or acetone, but especially C1 - C6 alcohols such. B. methanol, ethanol, propanol, butanol, pentanol, hexanol or their isomers. Lower alcohols, in particular methanol and ethanol, are usually used because they are easy to handle and have a relatively low vapor pressure.

In particular, C1 - C4 alkyl esters, ie methyl esters, ethyl esters, propyl esters or butyl esters of silica, are used as the starting silicon compound. The silicic acid methyl ester is preferred.

The concentration of the silicon starting compound in the organic solvent is usually about 0.05-1 mol / liter. To this solution, 0.05-12% by weight of water, preferably distilled water and 0.01-7% by weight of an acid catalyst, is added for the hydrolysis of the starting silicon compound. Organic acids such as acetic acid, ethoxyacetic acid, methoxyacetic acid, polyether carboxylic acids (e.g. Ethoxyethoxyacetic acid) citric acid, paratoluenesulfonic acid, lactic acid, methyl acrylic acid or acrylic acid or mineral acids such as ENT₃, HCl, H₂SO₄ or admitted.

The pH value of the solution should be between pH 0.5 and pH 3. If the solution is not acidic enough (ph&gt; 3), there is a risk that the polycondensates / clusters will enlarge. If the solution becomes too acidic, there is a risk that the solution will gel.

In a further embodiment, the solution can be prepared in two steps. The first step is as described above. This solution is now left to mature. The ripening time is achieved by diluting the ripened solution with additional solvent and stopping the ripening by shifting the pH of the solution to the strongly acidic range. Shifting into a pH range of 1.5 to 2.5 is preferred. The shift of the pH into the strongly acidic range is preferably carried out by adding an inorganic acid, in particular by adding hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid or else organic acids, such as. B. oxalic acid or the like. The strong acid is preferably added in an organic solvent, in particular in the solvent in which the silicon starting compound is also dissolved. It is also possible to add the acid in so much solvent, especially again in alcoholic solution, that the starting solution is diluted and stopped in one step. In a particular embodiment, the hydrolysis is wholly or partly in alkaline, for example using NH₄OH and / or tetramethyl ammonium hydroxide and / or NaOH carried out.

The sol-gel coatings contain precondensed particles and clusters, which can have different structures. In fact, these structures can be demonstrated with scattered light experiments. These structures can be produced in brines by process parameters such as temperature, dossier rates, stirring speed, but especially by the pH value. It has been shown that with the aid of small silicon oxide polycondensates / clusters with a diameter of less than or equal to 20 nm, preferably less than or equal to 4 nm, and particularly preferably in the range from 1 to 2 nm, immersion layers which are more densely packed can be produced , than conventional silicon oxide layers. This alone leads to an improvement in chemical resistance.

A further improvement in the chemical resistance and the function as an adhesion promoter layer is achieved by adding small amounts of an admixture to the solution, which is distributed homogeneously in the solution and is likewise distributed in the later layer and forms a mixed oxide. Suitable admixtures are hydrolyzable or Dissociating inorganic salts of tin, aluminum, phosphorus, boron, cerium, zirconium, titanium, cesium, barium, strontium, niobium or magnesium, e.g. B. SnCI₄, SnCI₂, AICI₃, AI (N0₃)₃, Mg (NO₃)₂, MgCI₂, MgSO₄, TiCI₄, ZrCI₄, CeCI₃, Ce (NO₃)₃ and the same. These inorganic salts can be used both in water-containing form and with water of crystallization. They are generally preferred because of their low price.

In a further embodiment according to the invention, one or more of the metal alkoxides of tin, aluminum, phosphorus, boron, cerium, zirconium, titanium, cesium, barium, strontium, niobium or magnesium, preferably titanium, zirconium, aluminum or niobium, be used. Also suitable are phosphoric acid esters, such as phosphoric acid methyl or Ethyl esters, phosphorus halides, such as chlorides and bromides, boric acid esters, such as ethyl, methyl, butyl or propyl ester, boric anhydride, BBr₃, BCI₃, Magnesium methylate or ethylate and the like.

This one or more admixtures is added, for example, in a concentration of about 0.5-20% by weight, calculated as oxide, based on the silicon content of the solution, calculated as SiO '.

The admixtures can also be used in any combination with one another.

If the immersion solution is to be used or stored for a longer period of time, it can be advantageous if the solution is stabilized by adding one or more complexing agents. These complexing agents must be soluble in the immersion solution and should advantageously be related to the solvent in the immersion solution.

Examples of complexing agents which can be used are ethyl acetoacetate, 2,4-pentanedione (acetylacetone), 3,5-heptanedione, 4,6-nonanedione or 3-methyl-2,4-pentanedione, 2-methylacetylacetone, triethanolamine, diethanolamine, Ethanolamine, 1,3-propanediol, 1,5-pentanediol, carboxylic acids such as acetic acid, propionic acid, ethoxyacetic acid, methoxyacetic acid, polyether carboxylic acids (e.g.

Ethoxyethoxyacetic acid) citric acid, lactic acid, methyl acrylic acid, acrylic acid.

The molar ratio of complexing agent to semimetal oxide and / or metal oxide precursor is 0.1 to 5.

Examples:

The production of the finished layers was carried out as follows: A float glass pane with a size of 10 x 20 cm, which had been carefully cleaned in a washing process, was dipped into the respective immersion solution. The disc was then moved at a speed of 6 mm / sec. pulled out again, the moisture content of the ambient atmosphere between 4 g / m³ and 12 g / m³ lies, preferably 8 g / m³ amounted to. The solvent was then evaporated at 90 to 100 ° C and then the layer was baked at a temperature of 450 ° C for 20 minutes. The layer thickness of the layers produced in this way was approximately 90 nm.

Production of sample solutions:

1 . Diving solution

125 ml of ethanol are introduced. 45 ml of silica, 48 ml of dist. Water and 6 ml of glacial acetic acid. After the addition of water and acetic acid, the solution is stirred for 4 hours, the temperature not being allowed to exceed 40 ° C. G are egebenenfalls has the solution cooled. The reaction solution is then diluted with 675 ml of ethanol and 1 ml of HCl is added. 10 g of SnCI are then added to this solution₄ x 6H₂O dissolved in 95 ml of ethanol and 5 ml of acetylacetone.

2nd Diving solution

125 ml of ethanol are introduced. 45 ml of silica, 48 ml of dist. Water and 1.7 g of 37% HCl added. After the addition of water and hydrochloric acid, the solution is stirred for 10 minutes, the temperature not being allowed to exceed 40 ° C. The solution may need to be cooled. The reaction solution is then diluted with 675 ml of ethanol. 10 g of SnCI are then added to this solution₄ x 6H₂O dissolved in 95 ml of ethanol and 5 ml of acetylacetone.

3rd Diving solution

60.5 ml of tetraethyl silicate, 30 ml of distilled water and 11.5 g of 1N nitric acid are added to 125 ml of ethanol with stirring. After the addition of water and nitric acid, the solution is stirred for 10 minutes, the temperature not being allowed to exceed 40 ° C. The solution may need to be cooled. The solution is then diluted with 675 ml of ethanol. After 24 h, 10.9 g of AI (NO₃)₃ x 9 H₂O dissolved in 95 ml of ethanol and 5 ml of acetylacetone.

4th Diving solution

60.5 ml of tetraethyl silicate, 30 ml of distilled water and 11.5 g of 1N nitric acid are added to 125 ml of ethanol with stirring. After the addition of water and nitric acid, the solution is stirred for 10 minutes, the temperature not exceeding 40 ° C. The solution may need to be cooled. The solution is then diluted with 675 ml of ethanol. 9.9 g of tetrabutyl orthotitanate dissolved in 95 ml of ethanol and 4 g of ethyl acetate are added to this solution.

In a further preferred embodiment, a solution of silicon mixed oxide is applied to a carrier substrate and thermally solidified in the course of a thermal tempering process. The thermal solidification of the sol-gel layer takes place in situ with a subsequent thermal prestressing of the substrate at substrate surface temperatures above 500 ° C. This involves a very cost-effective production, since the prestressing and the thermal hardening of the adhesion promoter layer take place in one process. Depending on the temperature-time curve, the furnace temperature is around 650 ° C. After the temperature treatment, shock cooling takes place.

With the aforementioned solutions, chemically and mechanically stable mixed oxide layers are obtained as an adhesion promoter layer, the molar ratio of aluminum to silicon in the mixed oxide being between about 3% and about 30%, preferably between about 5% and preferably in the case of admixing to form aluminum-silicon mixed oxide layers about 20%, particularly preferably between about 7% and about 12%.

In a further embodiment of the invention, in order to produce a substrate element 12, as shown, for example, in FIG. 2, in addition to the example in accordance with FIG. 1, a cover layer 4 is applied to the adhesive layer 3 as a particulate or porous layer. This takes place in particular by means of a flame-pyrolytic coating, a thermal coating process, cold gas spraying or sputtering, the cover layer 4 preferably consisting of silicon oxide. The cover layer can also consist of a silicon mixed oxide. An admixture is, for example, an oxide of at least one of the elements aluminum, tin, magnesium, phosphorus, cerium, zirconium, titanium, cesium, barium, strontium, niobium, zinc, boron or magnesium fluoride.

Due to the sufficient open porosity of the cover layer 4, when an easy-to-clean layer is applied when using the substrate element 12, there can be an interaction between the molecules of the easy-to-clean coating and the adhesion promoter layer, which has the higher long-term stability of the easy-to-clean Coating ensures.

The invention also relates to the use of a substrate element according to the invention for coating with an easy-to-clean coating, in particular with an organofluorine compound. The substrate element comprises a carrier plate, in particular made of glass or glass ceramic, and an adhesion promoter layer, which comprises a mixed oxide, preferably a silicon mixed oxide, particularly preferably one with an oxide of at least one of the elements aluminum, tin, magnesium, phosphorus, cerium, zirconium, titanium, cesium , Barium, strontium, niobium, zinc, boron or silicon oxide mixed with magnesium fluoride, preferably containing at least one oxide of the element aluminum. In one embodiment of the use of a substrate element according to the invention for coating with an easy-to-clean coating, a cover layer is arranged over the adhesion promoter layer. This cover layer is a particulate or porous layer, in particular made of silicon oxide, wherein the silicon oxide can also be a mixed silicon oxide.

Such substrates according to the invention are used for coating with an easy-to-clean coating. In particular, this easy-to-clean coating can be an anti-fingerprint coating or a non-stick coating. In the case of non-stick coatings, the layers appear very smooth, so that mechanical surface protection is achieved. The layers mentioned below usually have several properties from the area of ​​easy-to-clean, non-stick, anti-fingerprint, anti-glare or smoothing surface. Each of the products is better suited in one area, so that by choosing the right type of easy-to-clean coating in conjunction with the substrate element according to the invention, products with optimized easy-to-clean properties of particularly long-term durability can be achieved.

Easy-to-clean coatings are widely available on the market. In particular, they are organofluorine compounds, as described, for example, by DE 19848591. Known easy-to-clean coatings are products based on perfluoropolyether under the name “Fluorolink^® PFPE "such as" Fluorolink^® S10 "from Solvay Solexis or also" Optool ™ DSX "or" Optool ™ AES4-E "from Daikin Industries LTD," Hymocer^® EKG 6000N "from ETC products GmbH or fluorosilanes under the designation" FSD ", such as" FSD 2500 "or" FSD 4500 "from Cytonix LLC or Easy Clean Coating" ECC "- products such as" ECC 3000 "or" ECC 4000 "from 3M Deutschland GmbH. These are layers applied in liquid form. Anti-fingerprint coatings, for example as nano-layer systems, which are applied by means of physical vapor deposition, are Cotec GmbH is offered under the name "DURALON UltraTec".

In the continuation of the invention, substrates coated with the products have better properties, in particular long-term properties, when they are applied to the inventive substrate element. The following examples are intended to illustrate this. After the coating had been applied, the test substrates were subjected to the following tests for characterization:

1 . Neutral salt spray test according to DIN EN 1096-2: 2001 -05 (NSS test)

The neutral salt spray test, in which the coated glass samples are exposed to a neutral salt water atmosphere at constant temperature for 21 days, has proven to be a particularly challenging test. The salt water spray causes the coating to be stressed. The glass samples are placed in a sample holder so that the samples form an angle of 15 ± 5 ° with the vertical. The neutral salt solution is prepared by dissolving pure NaCI in deionized water so that a concentration of (50 ± 5) g / l at (25 ± 2) ° C is reached. The saline solution is atomized through a suitable nozzle to create a salt spray. The operating temperature in the test chamber must be 35 ± 2 ° C.

Before the test and after 168 h, 336 h and 504 h test time, the contact angle to water is measured in order to characterize the stability of the hydrophobic property. If the contact angle fell below 60 °, the test was stopped because this correlated with a loss of the hydrophobic property.

2nd Contact angle measurement The contact angle measurement was carried out with the PCA100 device, which enables determination of the contact angle with various liquids and the surface energy.

The measuring range ranges from 10 to 150 ° for the contact angle and 1 for the surface energy ^*10^"2 up to 2^*10³ mN / m. Depending on the procurement of the surfaces (cleanliness, uniformity of the surface), the contact angle can be determined to within 1 °. The accuracy of the surface energy depends on how exactly the individual contact angles are on a regression line calculated according to Owens-Wendt-Kaelble and is also given as a regression value.

Samples of any size can be measured because it is a portable device and it can be placed on large slices for measurement. The sample must be at least large enough that a drop can be placed on it without interfering with the edge of the sample. The program can handle different drop methods. Here the Sessil Drop method (lying drop) is usually used and evaluated with the "ellipse fitting" (Ellipse method).

Before the measurement, the sample surface is cleaned with ethanol. Then the sample is positioned, the measuring liquid is dripped on and the contact angle is measured. The surface energy (polar and disperse fraction) is determined from a regression line adjusted according to Owens-Wendt-Kaelble.

To get a measure of the long-term durability, a contact angle measurement is carried out after a long-lasting NSS test.

For the measurement results shown here, deionized water was used as the measuring liquid. The error tolerance of the measurement results is ± 4 °

3rd Fingerprint test The fingerprint test is used for the reproducible application of a fingerprint to a substrate surface and for assessing the cleanability.

The experiment shows the intensity of a fingerprint on a corresponding sample surface. With a stamp, a reproducible, reproducible fingerprint is applied to a substrate surface to assess fingerprint abnormality. The stamp with a stamp plate made of solvent-resistant material has a base area of ​​3.5x3.9 cm² and has a structure of concentric rings with a groove spacing of approximately 1.2 mm and a groove depth of approximately 0.5 mm. The following 3 test media are applied to the stamp surface:

A hand welding solution according to BMW test specification 506, made from 50 g alkaline artificial welding according to DIN ISO 105-E04, 2 g paraffin oil, 1, 5 g lecithin (Fluid Lecithin Super, from Brennnessel Munich) and 0.3 g gel former (PNC400, from. Nettle Munich) used.

To apply the test medium, a felt is soaked in a Petri dish with the medium and the stamp with a weight of 1 kg is pressed onto the soaked felt. The stamp is then pressed onto the substrate surface to be stamped with 3 kg. The substrate surface must be free of dust, grease and dry before starting the test. The stamp image as an impression in the form of individual rings must not be smeared afterwards. At least three fingerprints are stamped. Before the assessment, the fingerprints are dried for approx. 12 hours. When evaluating the print, it should be determined how much of a print medium remains on the sample surface and how flat it can spread out. For this purpose, the print is illuminated with a KL1500LCD cold light lamp (from Schott) with a split ring light in a camera measuring station, photographed and analyzed via an image evaluation using the Nl Vision image evaluation software. The prints are only taken without gloss in order to make an image evaluation possible. The intensity values ​​of the light scattered by the fingerprint, the scattered light, are determined and the mean value and scatter width are calculated. The spread should be less than or equal to 0.065.

Production of sample sample 1 - substrate element according to the invention corresponding to FIG. 1:

To prepare the immersion solution, 60.5 ml of tetraethyl silicate, 30 ml of distilled water and 1 1.5 g of 1 N nitric acid are added in 125 ml of ethanol with stirring. After the addition of water and nitric acid, the solution is stirred for 10 minutes, the temperature not exceeding 40 ° C. The solution may need to be cooled. The solution is then diluted with 675 ml of ethanol. After 24 h, 10.9 g of AI (NO₃)₃ x 9 H₂O dissolved in 95 ml of ethanol and 5 ml of acetylacetone.

A carefully cleaned borosilicate float glass pane 2 in the format 10 x 20 cm was immersed in the immersion solution. The disc was moved at a speed of 6 mm / sec. pulled out again, the moisture content of the ambient atmosphere between 5 g / m³ and 12 g / m³, preferably 8 g / m³ lay. The solvent was then evaporated at 90 to 100 ° C and then the layer was baked at a temperature of 450 ° C for 20 minutes. The layer thickness of the adhesion promoter layer 3 thus produced was approximately 90 nm.

Production of sample sample 2 - comparative sample:

For comparison, a conventional silicon coating using the sol-gel immersion process is to be used as an adhesion promoter layer according to the prior art.

125 ml of ethanol are introduced to prepare the immersion solution. 45 ml of silicic acid methyl ester, 40 ml of dist. Water and 5 ml of glacial acetic acid. After the addition of water and acetic acid, the solution is stirred for 4 hours, the temperature not being allowed to exceed 40 ° C. The solution may need to be cooled. The reaction solution is then diluted with 790 ml of ethanol and 1 ml of HCl is added.

A carefully cleaned 10 x 20 cm borosilicate float glass pane was immersed in the immersion solution. The disc was then moved at a speed of 6 mm / sec. pulled out again, the moisture content of the ambient atmosphere between 5 g / m³ and 10 g / m³, preferably at 8g / m³ lay. The solvent was then evaporated at 90 to 100 ° C and then the layer was baked at a temperature of 450 ° C for 20 minutes. The layer thickness of the layer produced in this way was approximately 90 nm.

Production of sample sample 3 - comparative sample:

A cleaned borosilicate float glass pane without an adhesive layer was provided as a substrate for a coating with an easy-to-clean coating.

The substrates produced in this way were each coated with the following easy-to-clean coatings. The substrates of sample example 1 according to the invention have the designations sample 1 -1 to 1 -4, the comparison substrates have the designations sample 2-1 to 2-4 or sample 3-1 to 3-4

Sample 1 -1, 2-1 and 3-1:

"Optool ™ AES4-E" from Daikin Industries LTD, a perfluoroether with terminal silane residue

Sample 1 -2, 2-2 and 3-2: "Fluorolink" S10 "from Solvay Solexis, a perfluoroether with two terminal silane residues

Sample 1 -3, 2-3 and 3-3:

A separate coating formulation with the designation “F5” was also used for the test of the substrate element according to the invention for coating with an easy-to-clean coating, Dynasylan being the precursor^® F 8261 was used by Evonik. 5 g Precursor Dynasylan were used to prepare the concentrate^® F 8261, 10 g ethanol, 2.5 g H₂O and 0.24 g HCL mixed and stirred for 2 min. 3.5 g of concentrate were mixed with 500 ml of ethanol to form coating formulation F5.

Sample 1 -4, 2-4 and 3-4:

"Duralon UltraTec" from Cotec GmbH, Frankenstrasse 19, 0-63791 Karlstein With this coating, the substrate glasses are treated in a vacuum process. The substrate glasses coated with the respective adhesive layer are placed in a vacuum container, which is then evacuated to a rough vacuum. Duralon UltraTec "is bound in the form of a tablet (14 mm in diameter, 5 mm in height) and placed in an evaporator which is located in the vacuum container. From this evaporator, the coating material is then evaporated out of the packing of the tablet at temperatures of 100 ° C. to 400 ° C. and is deposited on the surface of the adhesion promoter layer of the substrate. The time and temperature profiles are set as specified by Cotec GmbH for vaporizing the tablet made of the material "Duralon UltraTec".

In the process, the substrates reach a slightly elevated temperature, which is in the range between 300K to 370K.

Test results The samples were examined before, during and after the neutral salt spray test (NSS test) and the constant climate test (KK test). The water contact angle and fingerprint properties were determined on the samples before and during the neutral salt spray test (NSS test). The results are shown in Tables 1 to 3.

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Table 1: Results after neutral salt spray test (NSS test)

Description: Samples 1 -X with adhesion promoter layer, Samples 2-X with silicon oxide layer according to the state of the art, Samples 3-X without coating

Contact angle measurement [°]

Coating

drawing (one-sided) before after after after

Test 168 h 336 h 504 h

Sample 1 -1 Optool ™ AES4-E 102 95 93 90 Sample 2-1 Optool ™ AES4-E 100 58 - -

Sample 3-1 Optool ™ AES4-E 104 67 - -

Sample 1 -2 Fluorolink^® S10 102 100 97 98

Sample 2-2 Fluorolink^® S10 103 56 - -

Sample 3-2 Fluorolink^® S10 105 63 - -

Sample 1 -3 F5 103 89 81 79

Sample 2-3 F5 103 59 - -

Sample 3-3 F5 101 51 - -

Sample 1 -4 Duralon UltraTec 106 104 102 101

Sample 2-4 Duralon UltraTec 109 32 - -

Sample 3-4 Duralon UltraTec 104 45 - -

Table 2: Water contact angle measurements before and in the course of the neutral salt spray test (NSS test) as a function of time.

Description: Samples 1 -X with adhesion promoter layer, Samples 2-X with silicon oxide layer according to the state of the art, Samples 3-X without coating

Medium 7 BMW hand welding solution

Coating mean value intensity

Average value of intensity (one-sided) on the evaluation areas on the evaluation area after 405 h exposure before the test

in the NSS test

Sample 1 -1 Optool ™ AES4-E 0.05 0.20

Sample 2-1 Optool ™ AES4-E 0.06 0.25

Sample 3-1 Optool ™ AES4-E 0.07 0.26

Sample 1 -2 Fluorolink^® S10 0.06 0.13

Sample 2-2 Fluorolink^® S10 0.06 0.25

Sample 3-2 Fluorolink^® S10 0.06 0.25

Sample 1 -3 F5 0.06 0.17

Sample 2-3 F5 0.06 0.25

Sample 3-3 F5 0.06 0.23

Sample 1 -5 Duralon UltraTec 0.08 0.06 Sample 2-5 Duralon UltraTec 0.05 0.09

Sample 3-5 Duralon UltraTec 0.07 0.10

Table 3: Results after fingerprint test with Medium 7 BMW hand perspiration solution before and after three weeks of exposure to neutral salt spray (NSS test). Description: Samples 1 -X with adhesion promoter layer, Samples 2-X with silicon oxide layer according to the state of the art, Samples 3-X without coating

The samples with an inventive adhesion promoter layer as the base for an easy-to-clean coating do not show any noticeable attack (OK = OK) with only a slight change in color even after a test period of 504 hours. In contrast, a state-of-the-art sol-gel silicon oxide coating as the substrate for an easy-to-clean coating already shows a strong attack (not ok = not OK) with a strong color change after only 168 hours of testing. The resistance of the ETC layer in the NSS test could be increased to greater than 21 days by application to the substrate according to the invention without any visible attack.

The inventive adhesion promoter layer on a substrate as the basis for the different easy-to-clean coatings gives them a significant improvement in their long-term durability in all cases. In comparison, an easy-to-clean coating on a substrate without an adhesion promoter layer shows a loss of the hydrophobic property after only 168 hours of the NSS test. To maintain a high contact angle, for practically relevant easy-to-clean properties, this should be over 80 °. This was recognized as a good indicator to determine the preservation of the properties after a stress test. As a widely recognized test, the NSS test is one of the critical tests for such coatings. It reflects stresses that arise, for example, from touching fingerprints. The salt content of finger sweat is a typical influence for layer failure. Long-term durability is considered a key property. Overall, a lower anti-fingerprint property with longer durability is rated better than a very good anti-fingerprint property with poor long-term durability. The NSS test has a significant relevance with regard to real touch and outdoor applications such as touch panels and touch screens.

After an easy-to-clean coating has been applied to the adhesion promoter layer according to the invention, the water contact angle to the easy-to-clean coating after a three times longer exposure in the neutral salt spray test is higher than with the same easy-to-clean coating which is applied without an adhesion promoter layer with a correspondingly shorter load in the neutral salt spray test. If the water contact angle drops by up to 10% in the long-term NSS test, the easy-to-clean layer is not yet significantly attacked; if the water contact angle drops to less than 50 °, it can be concluded that the easy-to-clean layer is not exists more or only severely damaged and has lost its effect.

For example, the measurement results in Table 2 for all different easy-to-clean coatings on a clean glass surface or on a silicon oxide coating according to the prior art show a largely to complete loss of the easy-to-clean or anti-fingerprint property after only 7 days, whereas the same coatings on the adhesion promoter layer according to the invention have partially retained their effectiveness in full even after 21 days.

The results show that for all investigated organofluorine compounds, the inventive substrate element with an adhesion promoter layer causes a significant increase in the resistance.

Nevertheless, differences can naturally be observed between the different easy-to-clean systems, since in addition to the adhesion promoter layer, the basic stability of the easy-to-clean layer also has an influence on the resistance. Regardless of the particular fluoroorganic compound, however, a continuous effect can be observed, which in particular significantly improves the long-term effect of an easy-to-clean coating. The effect arises from the fact that the easy-to-clean coating interacts with the adhesion promoter layer.

Antifingerprint test results confirm the advantage of the inventive substrate elements as the basis for an easy-to-clean coating. Table 3 n shows the analysis of the intensity of the scattered light from the applied standard fingerprint for the samples with and without an adhesion promoter layer before and after exposure for 17 days in a neutral salt spray test (NSS test). Depending on the type of ETC coating, the results show an improvement in the anti-fingerprint property immediately after coating. But above all, the results show a significant improvement in the AFP property after long-term exposure in the NSS test, ie the AFP effect of an ETC coating is significantly more stable in the long term using a substrate element according to the invention for the coating than for a conventional substrate without an adhesion promoter layer.

Inventive substrate elements coated with an easy-to-clean coating are used as a cover with a protective function. In this case, all base materials of the conventional covers and protective devices can serve as carrier material for a substrate element according to the invention and can be provided with an adhesion promoter layer and an easy-to-clean coating.

Inventive substrate elements coated with an easy-to-clean coating continue to be used as a substrate with a touch function. All suitable materials, such as metals, plastics, glasses or composite materials, which are equipped with a touch function, can be used as the carrier material. Displays with a touchscreen function are particularly important here. The long-term resistance to abrasion and chemical attack in the form of finger sweat such as salts and fats is particularly noteworthy here.

Applications are, for example, display screens from monitors or display front screens, each of which is used as a front screen with an air gap or as a front screen bonded directly to a display screen, optionally with a laminated polarizer.

Substrate elements according to the invention coated with an easy-to-clean coating can be used for all types of display applications, such as display applications with touchscreen function as single, dual or multi-touch displays, 3D displays or flexible displays.

Substrate elements according to the invention coated with an easy-to-clean coating are used as a substrate for all types of interactive input elements, which are in particular designed as a touch function, preferably with resistive, capacitive, optical, by means of touch technology acting by means of infrared or surface acoustic wave. Systems that work with light coupling, such as infrared or optical touch technologies, are particularly sensitive to the presence of dirt and deposits on the contact surface, since deposits can cause undesirable reflections. The use of a substrate element according to the invention coated with an easy-to-clean coating has particular advantages here. Other applications with long-term ETC or AFP properties are panes for interior and exterior architecture such as shop windows, glazing of pictures, showcases, counters, refrigeration units or with problematic accessibility for cleaning. In addition to good adhesion, scratch resistance and long-term durability, the UV resistance of the ETC layer is also important in architecture.

Other applications are, for example, stove front panels, decorative glass elements, in particular in areas with a high risk of contamination, such as kitchens, bathrooms or laboratories, or even covers for solar modules.

Inventive substrates coated with an easy-to-clean coating, in some cases also with an etched carrier material surface, are used as usage surfaces with anti-fingerprint, anti-graffity or anti-glare properties.

Especially decorative elements, which have a print on the back of the glass or have a reflective coating, benefit particularly from an easy-to-clean coating. These elements, which are used, for example, as stove top panes or in other kitchen appliances, repeatedly come into contact with fingerprints or greasy substances during use. In these cases, the surface quickly looks unsightly and unsanitary. The easy-to-clean coating already provides good visual results for suppression and is easier to clean. The longevity of the effect can be significantly increased by the substrate according to the invention in such an application and the utility value of an object is increased. It goes without saying that the invention is not restricted to a combination of the features described above, but that the person skilled in the art will combine any features of the invention as far as this makes sense.