EP1206165B1 - Cooking hob with transparent, not one-color glass ceramic panel or alternatively with a glass panel made with special tempered glass used as cooktop - Google Patents

Abstract

The cooking installation comprises a plate (1) whose bottom surface is provided with a unicolored layer (6), while the plate top has a decorative layer (7) covering its entire surface.

Description

The invention relates to a hob with a transparent, not colored glass ceramic plate or alternatively with a glass plate tempered special glass as cooking surface, with radiant heating elements has heated cooking zones, are attached to the decors and their Bottom of an IR-permeable layer of a temperature-resistant color wearing.

Hobs with a glass ceramic plate as a cooking surface are common Technology. Typically, as is apparent from EP 0 220 333, a glass ceramic plate, which is used with coloring ions to reduce the Transmission is colored so that the below the glass ceramic plate housed functional components of the hob practically from above are not visible. These cooking surfaces are therefore practically not transparent and appear black in supervision.

Cooking surfaces formed from the aforementioned glass ceramic plates are in provided with decors, be it purely for aesthetic reasons or around functional areas, such as the cooking zones, opposite other areas the cooking surface to delineate. These decors and their application to the Glass ceramic plate, for example, in DE 44 26 234 C 1 (= EP 0 693 464 B 1 and DE 34 33 880 C 2 described.

Because of the nontransparency of the colored glass ceramic plate therefore the decors on the cooking surface, including the so-called, for example from DE 197 28 881 C 1 (= DE 297 11 916.8 U 1) known vollflächendekorierten Cooking surfaces where the decor is almost completely the top the cooking surface covers, according to the o.a. State of the art with ceramic Enamel-based colors on the top, either typically by means of Screen printed, or there applied by the decal technique and then baked.

From DE-200 05 461 U1 it is known to serve as cooking surfaces Glass ceramic plates made of a transparent, non-colored glass ceramic and their underside with a temperature resistant paint too print. This color layer is once used to make the Nontransparency, i. it replaces the usual coloring, so that the plate in supervision also appears dark. The other is the bottom layer designed as a coloring decoration, whereas the top of the Glass ceramic plate without decoration, i. not so far coated.

By the sole coating of the underside of the glass ceramic plate with a dark color impression has this well-known hob once some conspicuousness to soiling, e.g. of fingerprints, and on the other hand, no protection against surface scratches, from metal abrasion and signs of wear.

The invention is based on the object, the aforementioned conspicuousness reduce and specify a surface protection or in a simple way to realize given color impressions.

The solution to this problem is achieved starting from the initially described Hob with a transparent, non-colored glass ceramic plate or Glass plate made of toughened special glass as cooking surface, with Radiant heating elements has heated cooking zones, on the decors are applied and whose underside carries an IR-permeable layer, according to the invention characterized in that the underside layer is plain is formed and the top of the glass ceramic or glass plate with a Full-surface decorative layer is provided. Through this combination you have the Possibility to achieve predetermined color impressions, otherwise only by the very complex coloring of the molten glass can be realized.

According to an essential development of the invention are the color pigments the plain-colored lower layer and the upper side Vollflächendekorschicht selected so that in plan view, a whitish or creamy or bisquitartiger color impression results.

The creamy or bisquitartige color impression in connection with the top-side full-surface decorative layer reduces in a special way Abnormalities of contamination, in particular of Fingerprints. The top-side full-surface decorative layer also provides protection from surface scratches, from metal abrasion and signs of wear.

According to one embodiment of the invention, the temperature-resistant Colors printed and baked. This method of printing allows a simple and thus economical production of the decorated Glass or glass ceramic plate, wherein in the case of glass ceramic plates the typical nub structure makes it difficult to paint.

As temperature-resistant colors come according to the development of Invention inks based on dissolved in organic solvents Metal and / or precious metal compounds are based and / or colloidal metals contain, so-called chandelier colors, precious metal resinates or in general "organometallic" colors, as well as organometallic colors, in addition can be pigmented as desired, as well as colors with a sol-gel-based matrix, which either have a characteristic intrinsic color and / or In addition, can be pigmented arbitrarily, being in the hot area preferably conventional, inorganic pigments or chandelier, pearlescent interference pigments or any mixtures of these pigments used can be.

For the cold range also come the above-mentioned organometallic Colors, luster colors, precious metal resinates, and / or additionally arbitrary pigmented organometallic colors, luster colors, precious metal resinates in Question, and / or organic colors, lakes, colors based on organic modified glasses and / or colors made from an organic binding matrix or sol-gel based matrix and conventional, organic Dyes or inorganic pigments, chandelier, metallic effect, pearlescent or Interference pigments or different mixtures of these pigments. The first mentioned "organometallic" colors and colors based on a Sol-gel matrix have the necessary temperature resistance, too the direct irradiation by the cooking zones heated To be able to withstand radiation elements permanently.

The aforementioned colors are, depending on the color material, at different Temperatures burned.

According to one embodiment of the invention are to achieve special Color effects in some cases from the aforementioned organometallic Solutions formed with metal and / or precious metal components as colors Decors that are usually opaque enough with organic colors or Colors consisting of an organic, preferably polymeric binding matrix or Matrix based on sol-gel and conventional, inorganic pigments, Chandelier, metallic effect, pearlescent or interference pigments or various Mixtures of these pigments contain deposited.

Depending on the required temperature resistance, i. depending on whether the Decors applied in the heated zone or in the cold area of the cooking surface is, are in accordance with a further embodiment of the invention combinations used of different colors. Because basically, each of the o. G. Colors individually or - as far as compatibility is given - in combination with every other one of the o. g. Colors are used, with the Temperature resistance of each color types, the degree of transparency the color layers and the desired color impressions the scope and affect the color combinations.

The organometallic solutions with metal and / or precious metal components formed colors can also be used to create new effects conventional, inorganic pigments, chandelier, metallic effect, perglaze or Interference pigments or various mixtures of these pigments be offset and, if necessary, with organic colors, paints, colors based on organically modified glasses and / or colors that come from a organic, preferably polymeric binding matrix or sol-gel based matrix exist and are pigmented arbitrarily, be backprinted.

Furthermore, combinations of transparent chandelier colors with Precious metal colors as negative pressure, especially in the cold range conceivable.

Depending on the required temperature resistance, i. depending on if it is is the heated zone or the cold zone of the cooking surface, only the aforementioned "organometallic" colors or a Combination of these colors with an organic color, a color coat, a color based on organically modified glasses or with colors that look good an organic, preferably polymeric binding matrix or a matrix Sol-gel-based and conventional, inorganic pigments, chandelier, Metallic effect, pearlescent or interference pigments or various Mixtures of these pigments are used.

According to one embodiment of the invention, the underside layer is through applied a multiple printing multiple layers. This can be advantageous, je according to the number of printing layers in multiple printing, the Transmittance can be adjusted, which in particular special Functional areas, such as display windows, can be displayed on the cooking surface. Furthermore, metallic effects can also be achieved in this way especially with regard to the possible combinations with stainless steel Kundsenseite are desired.

According to another embodiment of the invention, the hob is so designed that in the cold region of the glass or glass ceramic plate a laminated film, e.g. a thin aluminum foil or a temperature-resistant polyester or melamine resin film, with highly transparent Glue and only in the cooking zone hot areas a color layer the temperature-resistant colors applied, in particular a single-layered or multilayer precious metal and / or chandelier paint layer, the latter is preferred due to higher IR transparency.

Further embodiments of the invention will become apparent from the description an embodiment shown in the drawing, which is also the invention explained in more detail.

The single FIGURE shows a schematic sectional view of a Section of a hob with a transparent, not colored Glass ceramic plate 1 as a cooking surface.

This glass ceramic plate 1 has at least one indicated by dashed lines Cooking zone 2, the hot area, on which an electrically operated radiant heating element 3 is assigned. The hot region 2 typically has a Temperature of> about 350 ° C. It is surrounded by a dashed line indicated annular transition zone 4 with a thickness of 0 - 25 mm and the cold zone 5, in which the temperature is usually below 220 ° C is.

On the underside of the transparent glass ceramic plate 1 is a solid color Layer 6 applied from temperature-resistant colors. This layer 6, the may be formed multi-layered, consists of colors or Color combinations, one depending on the area of the plate on which they are are applied, have adapted high temperature resistance and their Applying to the underside of the plate is preferably done by printing.

In the hot region 2, the layer 6 consists of a layer section 6 a Colors made of organometallic solutions with metal and / or precious metal be formed. These are film-forming colors, the one or several precious metals - especially platinum, palladium, gold and silver - as well other metallic compounds dissolved in organic solvents, and / or metals colloidally containing and which substances such as resins, Cosolventien, and / or any additives are added which the color, Affect color intensity, adhesion or solubility of the chandelier colors. Manufacturers of such colors are e.g. Heraeus, Johnson Matthey, Cerdec. These colors are characterized by high color intensity at low Layer thickness and thus affect the strength of the cooking surfaces only slightly. The temperature resistance is between 500 depending on the color and 950 ° C in continuous operation and can with more temperature resistant colors temporarily up to 1000 ° C.

By printing twice or more times, the transmission in the visible spectral range can be further reduced. The infrared transmission depends on the simple printing - depending on the type of glass ceramic and the used Pressure screen - typically between 60 - 85%, resulting in heat transfer when cooking, especially when using bad dishes, contributes. This effect is supported by the material of the Glass ceramic plate 1 itself already has a very high IR transparency. Of the Branding occurs either in the primary fire, during the so-called Ceramization, as described in DE 35 05 922 C1, or in a special secondary firing at typ. 200 ° C to 900 ° C, preferably at approx. 460 to 650 ° C for less temperature resistant inks for about 5 to 60 minutes, or at about 460 ° C - 900 ° C for more temperature resistant colors, also for approx. 5 - 60 min. Further usable are the vorg. "Organometallic" Colors also in the transition region 4 and in the cold region 5 of the cooking surface, i. outside the cooking zone 2, where the temperature load of about 350 ° C at Edge of the cooking zone to approx. Room temperature at the outer edge of the cooking surface drops.

Here are mainly "organometallic", in particular chandelier colors used, which have a lower temperature resistance and of which have a wider color spectrum in the white / yellowish range stands.

For color distinction is in a preferred embodiment a others, e.g. lighter "organometallic" color used, if necessary, with a Cover layer is backprinted. The cover layer is in one case an organic Colour. The temperature resistance is common in this type of paint Max. 180 to 300 ° C. This causes between the cooking zone and the organic outer layer a gap of about 0 to 25 mm recessed must be in conjunction with the usually bright insulation ring the heating elements 3 as an additional design element for design Marking of the cooking zone, the cooking zone marking, is used, and both unprinted and with a more temperature resistant color can be printed.

When using e.g. Inks, the inorganic pigments, chandelier, Pearlescent, metallic effect or interference pigments or mixtures containing various pigments, and characterized by metallic luster may stand out due to the purely organic colors significantly higher temperature resistance of about 500 to 650 ° C on the top be omitted mentioned recess.

O. g. Colors can be used in the cold area both in conjunction with the Use "organometallic" colors as well as use alone.

Depending on the used topcoat color will be in connection with the different "organometallic" colors different color effects in white / yellowish Scored area.

Other possibilities of color design result from an addition of so-called effect pigments. The effect pigments are Chandelier, pearlescent or interference pigments, in contrast to conventional pigments, layers with different refractive indices own and therefore do not absorb and scatter light, but in Reflect dependence of the layer structure more or less strongly and transmit as well as metallic effect pigments, which like a mirror the light reflect directionally. Manufacturers are e.g. E. Merck, Darmstadt, BASF, Ludwigshafen - both Germany - as well as Mearl Corp., N.Y. USA, Karrira OY, Porl Finland, Tayca, Osaka, Japan.

It has been found that by addition of 0 to 20 wt .-% Effect pigments highlight the metallic effect. on the other hand showed too high a proportion of effect pigments (> 20 wt .-%) one Deterioration of adhesive properties, so that the preferred range between 0.1 and 10%.

Further design options arise through the use of organic colors in the lower-layer portions 6 b in the cold area 5. Depending on the hiding power of the colors, an additional topcoat may be required become.

As glass ceramic plates are both those with back-pimpled structure as well as smooth plates on both sides. The former own in generally a higher mechanical strength. The smooth plates on both sides but have the advantage that display elements, such as LED LCD displays, appear easy to read without additional immersion layers.

The number of layers can be in the range of functional zones, such as e.g. Display windows that specifically set transparency.

It is also conceivable another embodiment with a plain colored colored film in the cold region 5 instead of a color layer. The film is glued with transparent temperature-resistant adhesives on the underside of the glass ceramic plate 1. Examples of adhesives used are: acrylate adhesive coatings, for example from 3M, UV-curing adhesives, or highly transparent silicone adhesives, preferably 2-component systems. When lamination, attention must be paid to a bubble-free application. The adhesive layers must thereby possibly the knob structure (typ. 50 to 150 pm high) offset, a minimum layer thickness of 150 μ m thereby obtained. Furthermore, in the selection of the adhesive to ensure a sufficiently high water vapor resistance, since 3 steam is released during the heating of the insulating ring of the heating elements.

Instead of a glass ceramic plate 1, the cooking surface can also by a Tempered special glass sheet, e.g. Lithium aluminosilicate glass (LAS glass) or borosilicate glass.

1. Für den Heißbereich 6 a:

a: Lüsterfarben von Heraeus, D. Johnson Matthey, NL

b: Lüsterfarben, die konventionelle anorganische Pigmente, Lüster-Metalleffekt-, Perlglanz-, oder Interferenz-Pigmenten oder verschiedenste Mischungen dieser Pigmente enthalten

c: Sol-Gel-Schichten oder pigmentierte Sol-Gel-Schichten, die konventionelle anorganische Pigmente, Lüster-, Metalleffekt-, Perlglanz-, oder Interferenz-Pigmenten oder verschiedenste Mischungen dieser Pigmente enthalten

d: Edelmetallfarben, -resinate oder andere Farben, die auf Grund einer geringen IR-Transparenz stark aufgerastert gedruckt werden

e: Bevorzugt Borosilikatglas als Fluß mit TiO2 oder CeO2 als Pigment

2. Für den Kaltbereich 5:

• Mindestens bis 350° C, d.h. in direkten Anschluß an den Heißbereich druckbar (ohne Spalt) z.B.:
• a: Antikorrosionsfarben mit Metallpigmenten
• b: Lüsterfarben mit Temperaturstabilität bis zu 500° C, z.B. von Heraeus, D.; Johnson Matthey, NL.
• c: Lüsterfarben mit Temperaturstabilität bis zu 500° C, die konventionelle anorganische Pigmente, Lüster-, Metalleffekt-, Perlglanz-, oder Interferenz-Pigmenten oder verschiedenste Mischungen dieser Pigmente enthalten
• d: Edelmetallfarben, -resinate mit Temperaturstabilität bis zu 900° C, z. B. von Johnson Matthey, Heraeus, D., Cerdec
• e: Sol-Gel-Schichten oder pigmentierte Sol-Gel-Schichten, die konventionelle anorganische Pigmente, Lüster-, Metalleffekt-, Perlglanz-, oder Interferenz-Pigmenten oder verschiedenste Mischungen dieser Pigmente enthalten.
• Bis 300° C:
• f: organische Farben mit anorganischen Farbstoffen z.B.: Farblacke oder Hydroglasuren von der Firma Diegel, Alsfeld, D.
• Bis 180° C - 220° C:
• g: organische Farben mit organischen Farbstoffen, z.B. von Heraeus, D.
• h: Farben auf Basis organisch modifizierter Gläser
• i: auflaminierte Folien, z.B. Aluminiumfolien, Polyesterfolien, Melaminharzfolien
  • Desweiteren alle denkbaren Kombinationen aus den in 1 und 2 genannten Beschichtungsmitteln, z.B. im Kaltbereich 2b+2f, 2c+2f, 2b+2a, 2b+2d, 2b+2e etc.

In the following, the possible coating compositions for the individual sections 6 a, 6 b of the underside layer 6 are compiled:

1. For the hot area 6 a:

a: Luster colors by Heraeus, D. Johnson Matthey, NL

b: Luster colors containing conventional inorganic pigments, chandelier-metallic effect, pearlescent, or interference pigments or various mixtures of these pigments

c: Sol-gel layers or pigmented sol-gel layers containing conventional inorganic pigments, chandelier, metallic effect, pearlescent, or interference pigments or various mixtures of these pigments

d: Precious metal paints, resinates or other colors that are printed heavily rastered due to low IR transparency

e: Prefers borosilicate glass as flux with TiO 2 or CeO 2 as pigment

2. For cold area 5:

• At least up to 350 ° C, ie in direct connection to the hot area printable (without gap) eg:
• a: Anti-corrosion paints with metallic pigments
• b: Luster colors with temperature stability up to 500 ° C, eg from Heraeus, D .; Johnson Matthey, NL.
• c: Luster colors with temperature stability up to 500 ° C containing conventional inorganic pigments, chandeliers, metallic effect, pearlescent, or interference pigments or various mixtures of these pigments
• d: Precious metal paints, resorates with temperature stability up to 900 ° C, z. By Johnson Matthey, Heraeus, D., Cerdec
• e: sol-gel layers or pigmented sol-gel layers containing conventional inorganic pigments, luster, metal effect, pearlescent, or interference pigments or various mixtures of these pigments.
• Up to 300 ° C:
• f: organic colors with inorganic dyes, for example: color lakes or hydroglazes from Diegel, Alsfeld, D.
• Up to 180 ° C - 220 ° C:
• g: organic colors with organic dyes, eg from Heraeus, D.
• h: colors based on organically modified glasses
• i: laminated films, eg aluminum foils, polyester foils, melamine resin foils
  • Furthermore, all conceivable combinations of the coating agents mentioned in 1 and 2, for example in the cold area 2b + 2f, 2c + 2f, 2b + 2a, 2b + 2d, 2b + 2e, etc.

Depending on the type of coating is at different temperatures baked / dried / cured.

In addition to the lower-side, single-colored layer 6, the upper side of the glass-ceramic plate 1 is provided with a full-surface decorative layer 7, which preferably extends in the same way over the hot and cold regions 2, 5. This decorative layer 7 is preferably formed in accordance with DE 197 28 881 C1, ie ceramic inks are printed on the upper side of the glass-ceramic plate in such a way that at least two rater-shaped complementary and complementary to a closed, full-surface decorative covering of the surface Structural elements are applied as juxtaposed paint jobs. This decorative layer is preferably single-colored, and consists for example of a color layer with borosilicate glass as glass flow and ceramic pigments of TiO 2 and / or CeO 2. Also, a glass color according to DE 197 21 737 C1 with SiO ₂ and Al ₂ O ₃ as main components is applicable.

The color pigments of the unifarbenen underside layer 6 and the top-side full-surface decorative layer 7 are chosen so that in plan view on the coated glass ceramic plate 1 alternatively a whitish, covered whitish, creamy or bisquitartiges color impression results.

Claims (11)

1. Hob having a cooking area comprising a transparent, uncoloured glass-ceramic plate (1) or special prestressed glass plate and having cooking zones (2) which are heated with radiant heating elements (3), on which decorations have been applied and whose bottom face carries an IR-transparent layer (6), characterized in that the bottom-face layer (6) is of solid-colour design and the top face of the glass-ceramic or glass plate (1) has been provided with a full-area decorative layer (7).
2. Hob according to Claim 1, characterized in that the colour pigments of the solid-colour bottom-face layer (6) and those of the top-face full-area decorative layer (7) have been chosen so that the impression when viewed from above is of a whitish or creamy whitish or bisquelike colour.
3. Hob according to Claim 1 or 2, characterized in that the solid-colour bottom-face layer (6)

   is composed in the heating area (6a) of the cooking zones (2) of a material which is stable at temperatures greater than about 350°C, typically greater than 500°C, and

   is composed in the cold area (6b) of the cooking surface, outside the cooking zones (2), of a material which is stable at temperatures below about 350°C.
4. Hob according to one of Claims 1 to 3, characterized in that the bottom-face layer (6) has been built up, at least in the hot area (6a), from colours consisting of organometallic solutions having complexed and/or colloidal metal and/or noble-metal fractions, optionally comprising pigments or pigment mixtures.
5. Hob according to one of Claims 1 to 3, characterized in that the bottom-face layer (6) is composed at least in the hot area (6a) of sol-gel layers optionally comprising pigments or pigment mixtures.
6. Hob according to one of Claims 3 to 5, characterized in that in the cold area (5) and/or in the transition area (4), in which temperatures up to about 350°C are reached, the bottom-face layer (6b) is composed of lustre colours, with or without pigmentation, or of other organometallic colours, especially noble-metal resinates, anticorrosive colours, with or without pigmentation, or of sol-gel layers, with or without pigmentation, which are stable at least up to the said temperature.
7. Hob according to one of Claims 3 to 5, characterized in that in the cold area (5) and/or in the transition area (4), in which temperatures up to about 350°C are reached, the bottom-face layer (6b) is composed of organic colours, such as colour lakes, colours based on organically modified glasses and/or colours which are composed of an organic, preferably polymeric binding matrix or sol-gel-based matrix and comprise conventional, inorganic pigments, lustre pigments, metallic pigments, pearlescent or interference pigments or various mixtures of these pigments.
8. Hob according to one of Claims 4 to 7, characterized in that the bottom-face layer (6) in the hot, transition and cold areas (2, 4, 5) is composed in each case of a combination of the colours that are temperature-stable for that area.
9. Hob according to one of Claims 1 to 8, characterized in that the bottom-face layer (6) is of multi-ply design.
10. Hob according to one of Claims 1 to 9, characterized in that the bottom-face layer (6) is backed with a cover layer (8) made from a different colour.
11. Hob according to one of Claims 1 to 10, characterized in that in the cold area (5) of the glass or glass-ceramic plate (1) a sheet, preferably an aluminium sheet or a stainless-steel sheet or an appropriately temperature-stable polymeric sheet, such as a polyester sheet or melamine resin sheet, for example, is laminated on using high-transparency adhesives and that only in the hot areas (2) has a colour layer (6) made from the appropriate temperature-stable colours been applied.

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