DE102012108398B4 - Hob, Aperture, Geräteeinhausung and fireplace or furnace panel with a hologram and method for its or their preparation, and use of a substrate on which a phase hologram is applied - Google Patents

Abstract

A method for producing a hob, a panel, a device housing or a fireplace or stove window, comprising the steps: - providing a substrate, - applying a sol-gel layer, - embossing a phase hologram in the sol-gel layer, which is in this way is designed so that it is only visible when light falls from the side facing the hologram onto the hob or the panel or the device housing or the fireplace or stove window, - curing of the sol-gel layer.

Description

Field of the invention

The invention relates to decorative applications in the home appliance sector on high-temperature-resistant glass or glass ceramic substrates, such as a hob, a panel or a chimney panel. More particularly, the invention relates to cooktops or a chimney panel comprising a high temperature glass or glass ceramic substrate.

Background of the invention

Decorative applications are also playing an increasingly important role in the so-called hot area in the home appliance sector. For cooktops, screens and chimney windows, for example, transparent glass or glass-ceramic substrates are typically used. The glasses or glass ceramics used have a low coefficient of thermal expansion and are permanently temperature-resistant up to more than 500 ° C.

In order to provide such substrates with a decor, it is necessary that this decor is also permanently high temperature resistant.

Marking, also referred to as branding, for counterfeiting of products by holograms, as well as the use of recognition codes, for example as a manufacturer's proof, is widespread (eg bank notes, ID cards, data carriers). For this purpose, so-called embossed holograms are frequently used which have surface structures, preferably in the micro or nanometer structure range.

For this purpose, in particular hologram stickers or foils in which holograms or similar structures have been embossed are used. Furthermore, the embossing of preheated bodies (so-called hot stamping) such as in WO 2001/62494 A1 described, or known layers.

However, such holograms produced are not suitable to be used at the Einsatztemperturen with which, for example, hobs and fireplace viewing windows are used.

Other methods include, for example, the so-called. Explosive embossing of holograms, which, however, destroyed due to the short-term high energy usually the embossing template and high security measures needed.

Furthermore, the substrates used for home appliance high temperature applications such as cooktops and chimney panels often have scratches or minor defects on the substrate surface which desirably should be concealed or filled by means of a coating. However, this complicates the application of a decorative element, for example, in the form of a hologram due to the optical defect image.

In addition, it is often not possible to produce substrates with uneven surface morphology due to the production process, i. H. Surface structures of a few microns to a few hundred nm, to impress, because the embossing disappears due to the intrinsic roughness.

The document DE 10 2010 004 741 A1 shows an embossed sol-gel layer on which a metal layer is applied. The document US 4 856 857 A shows a phase hologram made of a polymer material.

Object of the invention

The invention is based on the object to provide for thermally loaded applications in the field of home appliance, such as hobs and / or Kaminsichtscheiben, decorative elements or other structures, such as a manufacturer or type plate, which have a high temperature stability.

Summary of the invention

The object of the invention is already achieved by a method for producing a hob, a panel, device housing or a furnace disc and by a hob or a fireplace visor according to one of the independent claims.

Preferred embodiments and further developments of the invention are to be taken from the respective subclaims.

The invention relates on the one hand to a method for producing a hob or a fireplace or oven window.

The hob is usually a glass-ceramic substrate, under which cooking plates are arranged, for example in the form of electric heating elements. It is understood that the invention can also be used for induction fields.

Such hobs are subject during operation of a high thermal load.

Furthermore, the invention relates to a fireplace or furnace window.

In particular, the invention relates to fireplace and furnace windows, in which the disc has direct contact with the working space of the furnace or chimney, so is exposed directly to heat.

Such Kaminsichtscheiben be used in particular in ovens, in which solid fuels are burned, such as wood stoves. But it is also conceivable to use the chimney panel for an oven for preparing food.

Such discs are usually also formed as glass ceramic discs, wherein a glass ceramic is used with a low coefficient of thermal expansion.

For this purpose, a lithium aluminosilicate (LAS) glass ceramic is preferably used with a crystal phase content of greater than 50% by volume, more preferably greater than 60% by volume. The preferred crystal phase is high quartz mixed crystal or keatite.

Depending on the temperature load, there are also heat-resistant or shock-resistant glasses, which are used at least for some applications in which the disc has direct contact with the working space. Exemplary heat shock resistant glasses may be borosilicate glasses.

In particular, substrates having a thermal coefficient of linear expansion α of less than 4.5 × 10 ^-6 K ^-1 , preferably of less than 4.1 × 10 ^-6 K ^-1 , particularly preferably less than 3.4 × 10 ^-6 K, are used ^{. 1} , used.

According to the invention, a sol-gel layer is first applied to the substrate, which is preferably transparent.

Preferably, a sol-gel layer based on UV-crosslinkable hydride polymer alkoxysilane is applied. Very particular preference is given to applying a hybrid-polymer sol-gel layer functionalized with chain-shaped oxidic nanoparticles.

Sol-gel layers are known in the art. Particularly suitable and preferably used sol gels or sol gel precursors are described in detail below.

In the sol-gel layer, a phase hologram is impressed.

A phase hologram is a hologram that has a surface relief, taking advantage of the fact that the light waves in the layer have a different propagation velocity than in the air.

In principle, it is known to generate the impression of a three-dimensional object via such phase holograms. The ideal viewing angle is usually in a range of 20 to 70 °, preferably from 30 to 50 °.

Within this viewing range, the hologram is very visible and brilliant. The brilliance depends on the lighting angle and the light source used. Particularly good effects are achieved when the hologram is illuminated with an approximately punctiform light source. For this purpose, in particular LED or halogen lamps can be used. With special optics even flatter illumination angles can be realized.

It is further known to the person skilled in the art that such phase holograms can be calculated by computer programs. The appearance of the desired three-dimensional object is entered into a computer program. Furthermore, material properties, in particular the refractive index of the material used, are entered and then a surface relief can be calculated by means of the computer which produces the impression of the desired three-dimensional object.

The embossing is done by means of a stamp. Thus, the structure of a master is transferred to the sol-gel layer in a mechanical way. It is understood that, during the production of the master, shrinkage occurring during subsequent processing steps must be taken into account and that, if appropriate, the structure depths of the master deviate from the desired structure depths of the later produced hologram.

The embossed structure is cured. The curing can be carried out in particular in two steps, wherein preferably first the sol-gel layer is cured by means of heating or by electromagnetic radiation such as UV radiation in such a way that the embossed structure is maintained. In a further step, the resulting composite material can be heated in such a way that organic constituents of the sol are predominantly removed and a heat-resistant (stable) layer is formed.

The inventors have found that with the manufacturing method according to the invention it is not only possible to produce holograms on a chimney panel or a hob in a very simple and efficient way, but at the same time that the sol-gel layer can serve for unevenness of the substrate, especially scratches and other depressions, to conceal by filling them.

In particular, valleys and scratches having a depth of more than 50 nm, preferably more than 100 nm and particularly preferably more than 300 nm, can be filled up by the sol and laminated in this way.

It is thus possible to use a substrate with a roughness R _a > 0.06 μm, an rms value of 0.08 μm and a PV value of 0.5 μm.

The surface values can be determined with the White Light Interference Microscope (WLI), the WLI is a 3D surface measurement and analysis system.

As such a device, for example, a ZYGO New View 200 CHR image zoom scanning white light interference microscope can be used.

The rms value is the English term for the R _q value (rms = root mean square and the q for R _q stands for square)

The average roughness value R _a is the arithmetic mean of the amounts of all profile values of the roughness profile and can be calculated in accordance with DIN EN ISO 4287, ASME B46.1.

The average roughness R _q / rms is the root mean square of all profile values of the roughness profile and can likewise be calculated in accordance with DIN EN ISO 4287, ASME B46.1.

The PV value denotes the vertical distance between the maximum peak and the maximum valley (lowest valley).

The invention makes it possible for the first time to use an at least partially transparent substrate on which a hologram is applied, as a hob or chimney pane, which is exposed to a temperature of over 300 ° C.

The temperature load can be done permanently during operation, d. H. Also, temperature loads of many hours do not lead to a degeneration of the layer or the composite of substrate and layer.

In most cases, it is advantageous for the production process, in particular from an economic point of view, to apply a structure to the finished substrate or precursor substrate.

In one embodiment of the invention, after the application of the sol-gel layer, a hot process such as ceramization, biasing of the substrate, or a substrate deforming process such as bending of the substrate is performed. Furthermore, there is a resistance to exposure to chemical agents, such as alcoholic or acidic or alkaline detergents.

With the method according to the invention, it is possible holograms, for example, designed as nameplate or other desired structures, eg. As decorative structures such as a flame pattern, flower pattern, logo or nameplate to apply to a substrate, which have a high temperature resistance due to their material composition.

Surprisingly, the chemical material composition or the microstructure of a sol-gel layer according to the invention makes it possible for the already embossed substrates to be ceramified, to be prestressed or deformed with little or no loss of the structure.

Furthermore, the layers, especially if they are baked at a temperature of at least 250 ° C, are particularly scratch-resistant and resistant to chemical cleaning agents.

This can be further improved by adding nanoparticles to the correspondingly used sol-gel material. Preferably, inorganic chain-like SiO ₂ nanoparticles having a chain length of 50-200 nm, preferably 60-150 nm, are added to the sol-gel material.

Furthermore, transparent scratch-resistant coatings can be applied. These can be oxidic, nitridic, oxynitiridic or carbidic layers or contain corresponding nanoparticles.

Conceivable, especially in addition, are also graphene, graphite particles or carbon nanotubes (CNT) and graphite or graphene layers or similar layers.

Surprisingly, it has also been found that the sol-gel layer, which is preferably applied by means of a liquid-phase coating method, fills existing scratches or cracks by penetrating the material and thus concealing it.

Such cracks can show depths of a few 100 nm. The critical crack / scratch depth is usually 1 μm.

By adjusting the refractive index of the sol-gel material to the substrate they can be completely laminated. Preferably, the difference in refractive index of the cured sol-gel layer and substrate is less than 0.35, preferably less than 0.25, and more preferably less than 0.15.

It has been found that when using other materials, as a rule, uneven surfaces can be embossed with a layer, but this embossing, in particular when the depths are in the range of surface inhomogeneities, is often no longer or only very slightly recognizable.

Surprisingly, it has been found that the SolGel material used in combination with the described embossing process allows to demonstrate the existing inhomogeneities of the substrate surface with a homogeneous film and then to emboss it below without a compensation of the inhomogeneities in total and thus the Reduction of the embossing.

Thus, the substrate used can be provided with an embossment which is transparent to visible light.

By the invention, a chimney panel can be provided with a hologram, which is not noticeable when firing the chimney or is not visible, but clearly when not fired fireplace, possibly via an external light source can be seen. The external light sources can be of a variety of designs and types, such as point, area or linear light sources based on LEDs or halogen systems or other systems known to those skilled in the art.

In addition, further decorative elements or markings, in particular manufacturer's markings, are conceivable.

A glass or glass-ceramic substrate may be provided in which the hologram has texture depths of a few μm to a few tens of nm.

The structures of the Phasenholgramms withstand a temperature load of at least 500 ° C for at least 60 minutes, preferably temperatures greater than 600 ° C, more preferably> 650 ° C.

• (i) Herstellung des Prägewerkzeugs,
• (ii) Beschichtung des Substrates mit dem zu prägenden Film (Sol-Gel-Schicht),
• (iii) Prägen,
• (iv) Aushärten der Struktur,
• (v) Aufbringen zusätzlicher dekorativer und/oder funktioneller Schichten.

The fabrication of a holgrammed substrate may include in detail the following steps:

• (i) production of the embossing tool,
• (ii) coating the substrate with the film to be embossed (sol-gel layer),
• (iii) embossing,
• (iv) curing the structure,
• (v) applying additional decorative and / or functional layers.

It is also possible to combine and repeat individual steps, such as, for example, combining steps (iii) and (iv) or applying a plurality of additional layers (v). Furthermore, the substrate used for step (ii) may already be partially or completely coated with further decorative or functional layers.

The embossing tool can be produced with a stamping template, wherein the stamping template is preferably made of a rigid material, which is suitable for multiple use. The embossing template comprises the structure to be embossed and the embossing tool is shaped as a negative mold. The embossing template can also be designed such that it is composed of several individual parts in order, for example, to realize a larger area or to allow combinations of different structures.

The embossing tool is preferably made of a soft elastic material, such as silicone or other plastics. It may be formed in a thickness of 0.5 mm to 20 mm, in particular embodiments as a film of a few microns thickness.

In other embodiments, the use of a rigid embossing tool is conceivable, for example in the form of a roller provided with the desired structure, then eliminates the production of the negative mold. In particular embodiments, the embossing tool may be provided with a functional layer, such as a hydrophobic, hydrophilic, oleophobic, oleophilic, anti-static or anti-adhesion layer.

After a so-called embossing process series, which may include some 1000 embossing steps, these embossing tools can be optionally cleaned by means of common cleaning solutions, such as ethanol or isopropanol or alkaline detergent, and subsequently used again.

The embossing template and thus the embossing tool can also be provided with several different structures, depending on the desired appearance or function.

Thus, for example, a hologram can be applied together with brushing optics or matting optics in a wide variety of geometries, such as, for example, a hologram in the middle of the substrate to be embossed later and a frame made of a matting optic.

The application of the layer to be embossed can take place over the entire surface, locally or partially structured.

Preferably, the sol-gel layer is applied to the substrate via a liquid coating process such as screen printing, dipping, flooding, spraying, spin coating, pad printing, inkjet, roller coating, slot casting, drop-on-demand, transfer technology, dip coating.

Particularly preferred is a continuous process.

In particular embodiments, the substrate coated with the layer to be embossed may already be provided with other decorative or functional layers or layer packages, such as colored, metallic, metallic-appearing, mirrored, partially mirrored, matted, Farbanpass-, adhesion promoter, barrier, Brechzahlvariations- Antireflective, infrared radiation reflecting, scratch protection, hard coatings, immersion layers and the combinations of these layers. It is also conceivable to apply one or more of these layers to the sol-gel layer.

Preferably, the layer to be embossed and the layers optionally arranged underneath are at least partially transparent to light in the visible range.

In special embodiments, however, semitransparent and opaque coatings are conceivable or combinations of transparent and / or semi-transparent and / or opaque regions, such as, for example, an opaque edge region with a transparent region in the middle of the substrate.

In one embodiment, the layer to be embossed, that is to say the applied sol-gel layer, is precured before the actual embossing step.

Pre-hardening is preferably carried out by means of photochemical or thermal processes, with particular preference being given to pre-hardening by means of IR radiation.

For embossing the hologram, the embossing tool is applied to the layer to be embossed, preferably starting continuously from one side.

But it is also the removal of the embossing tool conceivable, as static (at all points of the substrate at the same time) or depositing from the middle to the outside.

Also, the embossing tool may be provided with a layer of the material to be embossed. Subsequently, under defined pressure, the composite substrate / layer to be embossed / embossing tool is cured thermally and / or photochemically, preferably photochemically.

In a further embodiment, any resulting bubbles are removed by hand, a roller or by means of a slight negative pressure.

After removal of the embossing tool, a structured layer is obtained with a layer thickness in the range of less. The structures are predetermined by the structure of the stamping die.

This embossed layer, as provided in a further embodiment of the invention, can be structuring for at least one subsequent deposited layer. This follows the relief of the embossed sol-gel layer.

The structures are preferably cured depending on the required temperature resistance of the end product at temperatures of 50-1000 ° C, preferably at 130-700 ° C.

The structure is retained even if the organic constituents of the embossed layer are burned out, as provided in a preferred embodiment of the invention.

The structure depth or the structural shrinkage in relation to the structure of the embossing template decreases depending on the processing temperature and the material used of the layer to be embossed between 0-80%.

In a further development of the invention additional decorative and / or functional layers are applied.

The hologram can now be provided with at least one coloring and / or compensating and / or functional layer with a conventional coating method, such as CVD (chemical vapor deposition), PVD (physical vapor deposition) or liquid coating methods, preferably via sputtering processes.

For this purpose, the embossed sol-gel layer z. B. combined with an IR-reflecting layer, so that the impression of the hologram is not changed, but in addition by means of the IR reflective coating a pyrolysis effect, d. H. an increase in the temperature, for example, in the furnace interior can be achieved.

Furthermore, functional layers or layer packages are conceivable which include an antireflective, infrared radiation-reflecting, non-stick, anti-scratch, hard-material, barrier, catalytic, easy-to-clean (ETC), hydrophobic, hydrophilic, oleophobic, oleophilic, cracked resp. scratch-healing or sealing effect or combinations.

Additionally or alternatively, decorative layers, such as colored, metallic, seemingly metallic, mirrored, partially mirrored, matted layers are conceivable.

For example, a glass-ceramic substrate is conceivable which has a hologram in the middle and a frosted region on the edge, the complete substrate being provided with an additional IR-reflecting layer and the matted edge region having a metallic appearance.

These additional decorative and / or functional layers also meet the requirements for temperature and chemical resistance without loss of effect, such as the patterned layer of more than 500 ° C for at least 60 minutes, especially when deposited via a PVD or CVD process.

The embossing can be applied to the viewer facing or facing away. The additional decorative and / or functional layers or layer packages may be disposed below or above the embossed layer or on the side opposite the substrate of the embossment.

As sol-gel precursors preferably hydrolyzed and condensed epoxy- or methacrylate-functionalized alkoxysilanes filled with glassy and or crystalline nanoparticles of alcoholic dispersion are used, which can achieve a shrinkage of 0-25%.

Particularly preferred are irregularly shaped, fibrous particles (preferably SiO ₂ ) having a diameter of 15-5 nm and a length of 5-150 nm.

In another preferred embodiment of the sol-gel precursor, mixtures of spherical particles of various sizes of 5-125 nm are employed.

Other preferably used fibrous inorganic nanoparticles consist for example of TiO ₂ , ZrO ₂ , C, Si, ZnO, Al ₂ O ₃ , CeO ₂ .

About the chemical nature of the inorganic paint components (molecular disperse sol-gel shares + inorganic nanoparticles), the mechanical strength of the structured layer can be adjusted.

Preference is given in particular to material compositions which have a high sintering activity. Both glassy-crystalline compositions of, for example, molecularly disperse SiO ₂ from sol-gel precursors and crystalline and / or amorphous inorganic nanoparticles can be used.

Also, in the sol-gel embossing lacquer formulation, a composition can be adjusted directly via the choice of the sol-gel precursors, which makes it possible to produce particularly crack-resistant layers. By choosing the chain-shaped nanoparticles, it is possible to produce a high crack-free single layer thickness of up to 4 μm.

In a further embodiment, fluorescent and / or "up-down" or "down-up conversion" particles can also be added to the sol-gel precursor. These can serve as additional license plate protection.

The layer thickness of the sol-gel layer is preferably between 0.05-8 microns.

The layer material preferably consists predominantly of amorphous or hybrid polymer SiO ₂ with optionally proportions of amorphous or nanocrystalline oxide and / or non-oxide metal oxides (eg TiO ₂ , MgF ₂ , MgO _x F _y , CaF ₂ , CaO _x F _y , CaO, MgO, LiO, NaO, ZrO ₂ , 8YSZ, Al ₂ O ₃ , CeO ₂ , Gd ₂ O ₃ , Bi ₂ O ₃ , B ₂ O ₃ , ZnO, ITO, SiN, SiON, SiC, SiOC, TiN, TiC, TiON, TiOC ZrC, ZrN, ZrON, ZrOC) or their hydride polymeric derivatives or compounds or particles.

The coating solution for the sol-gel layer is preferably based on amorphous or crystalline molecular or colloidally disperse or hybrid polymer sol-gel precursors of silicon, titanium, boron, bismuth, sodium, lithium, zirconium, phosphorus, niobium, Hafnium, yttrium, aluminum, zinc, magnesium, calcium, tin (especially SiOR _x R _y TiOR _x X _y , ZrOR _x X _y , AlOR _x X _y , ZnOR _x X _y , MgOR _x X _y , CaOR _x X _y , SnOR _x X _y ). With OR: alcoholate, for example ethylate, methylate, propylate, butylate, with X: Cl, Br, I, F, with R: methyl, ethyl, butyl, propyl, phenyl, glycidyloxypropyl, methacryloxypropyl, Aly, vinyl,) In one particular embodiment, the average particle size of the sol-gel precursor is in a range of 0.05-200 nm, particularly preferably 1-100 nm. The particle shape may be both spherical and irregular.

A preferred embodiment is based on the use of a UV-curable sol-gel coating, in particular on a hybrid polymer hydrolyzed and condensed alkoxysilane precursor (glycidylpropyltriethoxysilane - GPTES, methacryloxypropyltriethoxysilane MPTES, allylsilane, vinylsilane), which acts as a binder for SiO ₂ nanoparticles.

Preferably, the hybrid polymeric alkoxysilane precursor is reacted with a tetraalkoxysilane, e.g. Tetraalkoxysilane, reacted by hydrolysis and condensation. The molar ratio of hybrid polymer silane precursor to tetraalkoxysilane is preferably 2: 1 to 5: 1.

Preference is further given to using SiO ₂ nanoparticles which are fixed with a binder whose degree of condensation is greater than 60%. The volume fraction of the SiO ₂ nanoparticles is preferably greater than 30%, preferably> 50%.

A characteristic of a thermally treated layer at temperatures greater than 200 ° C is that it is microporous or mesoporous and has an open porosity of 1-50%, preferably 20-40%, most preferably 25-35%.

If a layer is treated at 500 ° C., it is microporous or mesoporous, depending on the degree of filling, with a pore diameter of, for example, 0.5-15 nm, preferably 1.0 nm-8 nm, diameter.

In one embodiment, a sol-gel precursor complexed with methacrylic acid, such as, for example, titanium alkoxide and / or zirconium alkoxide reacted with methacrylic acid, can be used as the UV-crosslinking component.

In order to be able to produce screen-printable coating systems, preference is given to sol-gel precursors with a low solvent content. Preferred solvents for this purpose are those having a low vapor pressure, preferably less than 2 bar. For this purpose, for example, in the preparation of the sol-gel precursor, a solvent exchange of highly volatile alcohols against ethylene glycol monoethyl ether and / or ethylene glycol monoisopropyl ether and / or 4-hydroxy-4-methyl-2-pentanone and or terpineol and or diethylene glycol monoethyl ether.

In one embodiment, the embossing lacquer has a high content of polysiloxanes. In particular, branched or linear methyl and / or phenylpolysiloxanes are used for this purpose. In particular, these polysiloxanes are provided with UV-crosslinking organic functionalities.

Preference is given to using polysiloxanes which have a high inorganic solids content of more than 50% by mass and an average chain length of from 2,000 to 30,000 g / mol.

In one embodiment, the layer may also contain UV or thermally crosslinking organic or hybrid polymeric components.

In a preferred embodiment, the structured layer consists of more than 90% by mass, preferably 95%, very particularly preferably> 99% of SiO ₂ .

In this case, the layer-forming SiO _{2 is} preferably greater than 50% by mass, more preferably greater than 70% by mass, of the SiO ₂ nanoparticles used.

In one particular embodiment, the layers according to the invention simultaneously have a barrier effect, in particular with respect to diffusion.

A first curing step during the embossing process can take place by means of UV radiation and / or thermally in a temperature range of 30-270 ° C., preferably between 50-150 ° C.

In one embodiment, the curing takes place during the embossing process exclusively by UV light, in particular can be precured by a UV-permeable embossing tool, the sol-gel layer, while the embossing tool is in contact with the layer.

In a further embodiment, the final curing takes place thermally in a temperature range of 100-1000 ° C, preferably between 450-740 ° C.

The embossing tool is preferably applied with a contact pressure of 0.01-5 bar. In a particular embodiment, the embossing step takes place under vacuum.

In further embodiments, the liquid coating solutions are accompanied by compounds which have a wetting or wetting effect. In particular, these may be, for example, fluoroorganosilane compounds. In further embodiments, a special primer is used before the coating or a preconditioning step of the surface to be coated is carried out.

In further embodiments, the master structure and / or the stamp are coated with a monolayer-forming solutions which have a wetting or entendenenden effect.

In one embodiment, the embossing lacquer can be used as a 2 or 3-component lacquer system to avoid pot life problems.

The invention may be used as a decorative element or license plate protector for home appliance high temperature applications such as oven windows, attachment panes and cooktops.

Embodiment 1

In a vessel 22.3 g (0.08 mol) of GPTES (glycidyloxypropyltriethoxysilane) with 4.1 g (0.02 mol TEOS (tetraethoxysilane) are introduced and with 2.3 g Water, in which 0.344 g PTSH (paratoluene sulfonic acid) are dissolved, hydrolyzed. After stirring for 2 minutes, 110 g of a 15% by mass alcoholic dispersion of chain-shaped shaped SiO ₂ nanoparticles in isopropanol are added to this hydrolyzate.

The nanoparticles, for example, have a chain-like shape with a diameter of 5-15 nm and a length of 50-150 nm. To this solution 15 g Tripropylengycolmonomethylether be given and the volatile solvent removed at 100 mbar and 50 ° C bath temperature on a rotary evaporator. The Prägesol 0.6 g of the cationic photoinitiator Irgacure ^® 250 is added in 1 g Ethylenglycolisopropylether subsequently.

By means of screen printing using a 180% fabric, layers can be applied to borosilicate glass (Borofloat 33 from SCHOTT AG) with the paint system on one side. After drying the solvent at RT - 80 ° C with or without circulating air is structured with a phase hologram structured silicone stamp (PDMS) applied and then cured by means of a UV lamp through the stamp. After removal of the stamp, the structure of the stamp has been transferred to the nanoparticle-functionalized lacquer. The layers are now thermally cured at temperatures of 480 ° C for 10 min. The final layer thickness is 2.5-3 μm.

Embodiment 2:

In a vessel 22.3 g (0.08 mol) of GPTES (Methacryloxypropyltriethoxysilane) with 4.1 g (0.02 mol TEOS (tetraethoxysilane) are introduced and with 2.3 g of water in which dissolved 0.344 g of PTSH (paratoluene sulfonic acid) After stirring for 2 minutes, 110 g of a 15% by mass alcoholic dispersion of chain-shaped SiO ₂ nanoparticles in isopropanol are added to this hydrolyzate.

The nanoparticles, for example, have a chain-like shape with a diameter of 5-15 nm and a length of 50-150 nm. To this solution 15 g Tripropylengycolmonomethylether be given and the volatile solvent removed at 100 mbar and 50 ° C bath temperature on a rotary evaporator. Then 0.6 g of a radical photoinitiator are added to the embossing sol.

By means of screen printing using a 180% fabric, the lacquer system can be used to apply layers on transparent lithium aluminosilicate glass ceramics with a partial black enamel decoration. After drying the solvent at RT - 80 ° C with or without circulating air is structured with a phase hologram structured silicone stamp (PDMS) applied and then cured by means of a UV lamp through the stamp. After removal of the stamp, the structure of the stamp has been transferred to the nanoparticle-functionalized lacquer. The layers are now thermally cured at temperatures of 670 ° C for 4 min. The final layer thickness is 2.5-3 μm.

Description of the drawings

The invention will be described below with reference to the drawings 1 to 3 will be explained with reference to schematically illustrated embodiments. 1 shows a schematic view of a furnace 1 , It is an oven in this embodiment 1 in which an open flame burns in a working room during operation.

Typically, such ovens are operated with solid fuels, such as logs or pellets.

The working space of the furnace 1 is by a Kaminbeziehungsweise furnace window 2 visible. The fireplace visor 2 has direct contact with the working space of the furnace 1 and thus can have direct contact with the flames.

Especially in solid fuel furnaces such Kaminsichtscheiben are subject to high thermal loads, among other things, therefore, because the solid fuels burn unevenly and it comes at times to a large flame formation, in which the flames occur directly to the disc.

The fireplace visor 2 is therefore made of a heat-resistant glass-ceramic substrate.

On the fireplace visor 2 is a phase hologram in this embodiment of the invention 3 applied by a method described above.

The phase hologram 3 has in this embodiment, the visual impression of a blazing flame and is only visible when the chimney Sichtscheibe 2 is irradiated from the front with a light source. If, on the other hand, it is brighter in the working space of the furnace due to the blazing fire than by light sources outside the furnace, this is the phase hologram 3 not or hardly visible, so that in operation the appearance of the blazing fire is not disturbed by the hologram.

Is the oven 1 On the other hand, it is not in operation and if it is illuminated from the front, ideally with a substantially punctiform light source, the hologram creates the visual impression of a fire, which, due to the changing viewing angle, changes in such a way as to give the viewer the impression of a blazing flame ,

The fireplace visor 2 also has an edge 4 which is provided with an additional layer, in this embodiment a deposited metal layer. The deposited metal layer can be applied to an embossed sol-gel layer, which in this case is structuring the deposited metal layer, so that the visual impression of a metal frame can be produced. It is conceivable to provide a frameless designed as such disc ready, which has the edge of the optical impression of a frame due to the coating. phase hologram 3 and structuring layer of the frame 4 can be applied in one step.

2 schematically shows a further Auführungsbeispiel the invention, in which case a hob 5 is shown. The stove top 5 comprises a glass-ceramic substrate 6 , which due to underlying heating elements hotplates 7 having.

In this Auführungsbeispiel is on a hotplate 7 a phase hologram 8th applied in the form of a three-dimensional appearing lettering.

By virtue of the invention, heat-resistant holograms can be provided, even in the area of the plates 7 can be applied.

In addition to a decorative function, the hologram can also function as a tamper-evident and security feature.

Large-area holograms can be applied by the invention, in particular in a range of 2 × 2 cm to 100 × 100 cm.

3 shows a flow chart of the essential process steps in the manufacture of a hob according to the invention or a chimney panel.

First, a heat-resistant glass-ceramic substrate is provided. Due to the heat resistance of the coatings described, the glass-ceramic substrate can initially also be provided as so-called green glass, ie as a precursor substrate, in which the ceramization process still has to be carried out.

A sol-gel layer is applied to the glass-ceramic substrate.

Then, a previously calculated phase hologram is impressed by means of a stamping die, wherein in this embodiment of the invention pre-hardening is carried out by curing the sol used by means of UV light upon contact with the stamping die. This curing is preferably carried out by a UV-transparent transparent stamp.

The sol-gel layer is now dimensionally stable as far as it does not run when removing the stamp.

After removal of the embossing stamp, the sol-gel layer is thermally cured, whereby organic components of the sol are predominantly removed. There remains a substantially inorganic layer formed, which is highly temperature resistant.

Subsequently, in this embodiment of the invention, a thin silicon oxide layer is applied as a scratch-resistant layer.

By means of the invention, a simple and efficient method could be provided by means of which fireplace viewing windows and hobs can be provided with a hologram.

Claims (10)

A method of making a cooktop, panel, appliance enclosure, or fireplace or oven panel, comprising the steps of: Providing a substrate, Application of a sol-gel layer, Imprinting a phase hologram into the sol-gel layer, which is designed such that it is only visible when light from the side facing the hologram falls on the hob or the panel or the device housing or the chimney or furnace window, - curing the sol-gel layer. A method for producing a hob or a panel or a device housing or a fireplace or furnace panel according to the preceding claim, characterized in that a substrate made of glass ceramic is used. Process for the production of a hob or a cover or a device housing or a Fireplace or furnace window according to one of the preceding claims, characterized in that the embossed sol-gel layer is heated in such a way that organic constituents are predominantly removed. Method for producing a hob or a panel or a device housing or a fireplace or furnace window according to one of the preceding claims, characterized in that the substrate is bent at least in sections, in particular after the embossing. A method for producing a hob or a panel or a device housing or a fireplace or furnace panel according to any one of the preceding claims, characterized in that an uneven substrate is used, which valleys, in particular scratches, with a depth of more than 50 nm, preferably more than 100 nm, and more preferably more than 300 nm. A method for producing a hob or a panel or a device housing or a fireplace or furnace window according to one of the preceding claims, characterized in that the substrate has a roughness R _a greater than 0.1 microns, preferably greater than 0.2 microns. A process for producing a hob or a panel or a device housing or a fireplace or furnace panel, characterized in that substrate and sol-gel layer are coordinated such that the refractive index of the cured sol-gel layer less than 0.3 , preferably less than 0.2, more preferably less than 0.1, differs from the refractive index of the substrate. A method for producing a hob or a panel or a device housing or a fireplace or furnace panel according to any one of the preceding claims, characterized in that on the phase hologram, a further layer is arranged, in particular a Antikratzschicht, color layer or metallic layer. Cooktop or panel or device housing or fireplace or furnace panel, produced, in particular produced by a method according to any one of the preceding claims. Use of an at least partially transparent substrate on which a phase hologram is applied, as a hob or panel housing or fireplace or furnace panel, which is exposed to a temperature of about 300 ° C, wherein the Phasenholgramm is designed such that it is only visible when light from the side facing the hologram falls on the hob or the panel or the equipment housing or the chimney or furnace panel.

Images