JP6206024B2 - Glass top plate for gas cooker - Google Patents

Description

  The present invention relates to a glass top plate used in a gas cooker.

  A top plate for a cooker is installed on the top of an electromagnetic cooker or a gas cooker. An object to be heated such as a pan is placed on the cooking surface side of the top plate for the cooker, and the object to be heated is heated by a heating device inside the cooker. As a top plate for an electromagnetic cooker, a glass top plate (glass top plate) is widely used. On the other hand, an enamel top plate has been used as a top plate for a gas cooker, but in recent years, a glass top plate has attracted attention from the viewpoint of excellent design and easy cleaning.

  As a glass top plate for a cooker, a technique (Patent Documents 1 to 3) has been developed in which a decorative layer having a pearly luster and a metallic luster is provided on the back side of a substrate glass. By applying such a glossy decorative layer, the glass top plate for a cooker can exhibit excellent design properties.

JP 2001-213642 A JP 2001-233636 A Japanese Patent Laid-Open No. 2001-233637

  However, when a conventional glass top plate for a cooker is applied to a gas cooker, cooking stains such as cooking broth adhere to the back side of the glass top plate with a decorative layer, and the deposits are heated, so that cooking spots There was a problem that occurred. Specifically, it is necessary to form a heat source opening that penetrates the top plate in the thickness direction on the top plate for the gas cooker, but the simmered juice flows from the cooking surface side through the heat source opening to the back side. If it adheres to the surface, the soup will be gasified and soaked into the decorative layer to form a cooking spot. Since this cooking spot is visually recognized from the cooking surface side, there is a problem that the design of the glass top plate is impaired.

  In particular, in the glass top plate for a gas cooker, since there is an opening for the heat source for exposing the flame of the burner to the cooking surface side, the spilled juice and the heat source adhering to the back side through this heat source opening The position of becomes closer. Therefore, the above-mentioned problem that the squeezed juice is easily heated to a high temperature and cooking stains are easily formed.

  This invention is made | formed in view of this background, and it aims at providing the glass top plate for gas cookers which can suppress generation | occurrence | production of a cooking spot while being excellent in the designability.

One embodiment of the present invention is a glass for a gas cooker having a glass plate, a decoration layer having a thickness of 0.2 to 5 μm laminated on the back surface side of the glass plate, and a light shielding layer laminated on the decoration layer. In the top plate,
An opening for a heat source that penetrates the glass top plate for the gas cooker in the thickness direction;
The decoration layer is composed of silica as a main component, and includes a silica film containing at least one metal oxide selected from manganese oxide, cobalt oxide, and a composite oxide of Mn and Co, and dispersed in the silica film. Inorganic pigments,
In the decoration layer, the amount of Mn and / or Co in the metal oxide contained in the silica film is 0.5 to 50 parts by mass with respect to 100 parts by mass of silica. Located on the glass top plate.

  The glass top plate for a gas cooker includes a silica film containing silica as a main component and containing at least one metal oxide selected from manganese oxide, cobalt oxide, and a composite oxide of Mn and Co, and the silica film. The decorative layer having an inorganic pigment dispersed therein. Therefore, the decorative layer is excellent in denseness. For this reason, for example, even if the spilled juice flows through the opening for the heat source and adheres to the back surface of the glass top plate for the gas cooker, the end surface of the opening for the heat source, etc., the liquid spilled juice will permeate the decorative layer. It is possible to prevent cooking spots from being formed. Moreover, even if the spilled juice adhering to the back surface of the glass top plate for a gas cooker or the end face of the opening for the heat source is heated and gasified, the penetration into the decorative layer can be suppressed and a cooking spot will be formed. Can be suppressed.

That is, the glass top plate for a gas cooker exhibits excellent design properties of the decorative layer and can suppress the occurrence of cooking spots. Further, the light shielding layer can serve to conceal the internal structure of the gas cooker and can make the above-mentioned cooking stains inconspicuous.
Therefore, the said glass top plate for gas cookers can maintain the design property which was excellent in the decoration layer over a long period of time.

The partial top view of the glass top plate for gas cookers in an Example. The fragmentary sectional view of the glass top plate for gas cookers in an Example (II-II arrow directional cross-sectional view in FIG. 1). The partial expanded sectional view of the glass top plate for gas cookers in an Example. Explanatory drawing which shows the relationship between the kind and addition amount of the metal in the decoration layer in an experiment example, and color difference (DELTA) E. The digital camera photograph of the cooking surface side of the glass top plate (samples E1-E3 and samples E6-E8) for gas cookers after the cooking spot test in an experiment example. The digital camera photograph of the cooking surface side of the glass top plate (sample C1-sample C3) for gas cookers after the cooking spot test in an experiment example.

Next, a preferred embodiment of the glass top plate for a gas cooker will be described.
In the plate-shaped glass top plate for a gas cooker, a pan or the like is arranged, and the surface on the side visually recognized by the user is the cooking surface, and the opposite surface of the cooking surface is the back surface. The back surface is a surface facing an internal device of the gas cooker such as a gas pipe or an ignition device when the top plate is disposed on the gas cooker.

As described above, the glass top plate for a gas cooker includes a glass plate, a decorative layer laminated on the back side of the glass plate, and a light shielding layer laminated on the decorative layer.
The glass plate is preferably made of a transparent low expansion glass ceramic. The transparent low-expansion glass ceramics are preferably translucent and have a low expansion coefficient. For example, there is one in which a β-quartz solid solution is precipitated in the main crystal phase. The volume crystallinity of the low expansion glass ceramics on which the β-quartz solid solution is precipitated is about 70%, and the crystal size is 0.1 μm or less. The β-quartz solid solution exhibits a negative expansion characteristic and cancels out the positive expansion characteristic of the remaining glass phase, so that the thermal expansion coefficient becomes almost zero. The refractive index (nD) is 1.541, the size of the precipitated crystal of β-quartz solid solution is 0.1 μm or less, which is smaller than the wavelength of visible light, and the refractive indices of the crystal phase and the remaining glass phase are almost the same. Therefore, there is no scattering of light, it is transparent in appearance, and transmits light from the visible light region to the infrared region well.

The glass plate is preferably made of lithium aluminosilicate glass.
In this case, the mechanical strength and heat resistance required for the glass top plate for a gas cooker can be sufficiently ensured. Moreover, the thickness of a glass plate can be 2-6 mm, for example.

  The decorative layer includes a silica film and an inorganic pigment dispersed in the silica film. The silica film contains silica as a main component and contains at least one metal oxide selected from manganese oxide, cobalt oxide, and a composite oxide of Mn and Co. It is considered that the fact that the silica film containing this specific metal oxide is excellent in denseness contributes to the excellent denseness of the decorative layer described above.

The amount of Mn and / or Co in the metal oxide contained in the silica film is preferably 0.5 to 50 parts by mass with respect to 100 parts by mass of silica. If the lower limit is not reached, the effect of improving the denseness by the metal oxide may be insufficient. On the other hand, when this upper limit is exceeded, there is a possibility that the decorative layer has a deep yellowish tint. Furthermore, even if this upper limit is exceeded, the addition effect commensurate with the addition amount cannot be obtained. From the viewpoint of further improving the denseness, the amount of Mn and / or Co is more preferably 1 part by mass or more, further preferably 5 parts by mass or more, with respect to 100 parts by mass of silica. It is even more preferable that the amount is at least part by mass. Moreover, from a viewpoint of suppressing the yellowishness in a decoration layer more, it is more preferable that the amount of Mn and / or Co is 30 mass parts or less with respect to 100 mass parts of silica, and is 15 mass parts or less. Is more preferable. In addition, although the above-mentioned Mn amount and Co amount are not amounts as oxides but amounts of metal elements, Mn and Co in the silica film are actually manganese oxide, cobalt oxide, Mn and Co. It exists as a complex oxide. In addition, when the amount of Mn and / or Co described above contains only one of manganese oxide and cobalt oxide as a metal oxide, it is the amount of Mn or Co. Manganese oxide, cobalt oxide, and Mn When two or more kinds of complex oxides of Co and Co are contained, the total amount of all Mn amounts and Co amounts. From the viewpoint of lower cost, the metal oxide is preferably cobalt oxide.
The silica film can contain a metal oxide other than manganese oxide, cobalt oxide, and a composite oxide of Mn and Co as long as the effects of the present invention are not impaired.

The inorganic pigment is preferably a white pigment or a silver pigment.
In this case, the glass top plate for a gas cooker can exhibit a white, silver, or gold-based luxury design. Moreover, in the top plate having a white, silver or gold decorative layer, the above-mentioned cooking stain tends to be noticeable, but the above-mentioned glass top plate for a gas cooker has a high-density decoration as described above. Since it has a layer, even if it is a white type or silver type in which cooking spots are easily noticeable, formation of cooking spots can be suppressed. That is, in this case, the above-described effect that the occurrence of cooking spots can be suppressed becomes remarkable. As an inorganic pigment, a commercial item etc. can be utilized according to a desired color.

The inorganic pigment is preferably a pearl pigment.
In this case, the glass top plate for a gas cooker exhibits a glossy pearly color tone and can exhibit a more excellent design. Since the decorative layer contains the above-described metal oxide, it is possible to form a glossy decorative layer of silver to gold color tone by selecting a pearl pigment as the inorganic pigment as described above. The color tone of silver to gold can be adjusted by adjusting the amount of pearl pigment or metal oxide. Moreover, in the top plate having a pearl-like decorative layer, cooking spots tend to be noticeable. However, in the glass top plate for a gas cooker, the cooking spots are conspicuous because of the dense decorative layer as described above. Even if it has a decorative layer of easy color tone, the formation of cooking spots can be suppressed.

  As the pearl pigment, for example, an inorganic pigment coated with at least one selected from titanium oxide, zirconium oxide, and iron oxide can be used. That is, as the pearl-like pigment, for example, an inorganic pigment and a pearl-like film covering the inorganic pigment can be used. Examples of the inorganic pigment to be coated include kaolin, talc, sericite, pyroferrite, natural mica, synthetic mica, and aluminum oxide. A commercially available product can also be used as the pearl pigment.

  The decorative layer is produced by baking a coating material for forming a decorative layer containing at least a silica forming material composed of a silicone resin and / or silica sol, an inorganic pigment, and a metal resinate composed of Mn resinate and / or Co resinate. Can do. By this baking, a silica film is formed from the silica-forming material, and a metal oxide is generated from the metal resinate. The inorganic pigment is dispersed as particles in the silica film.

Silicone resin refers to a polymer of an organosilicon compound having a siloxane bond as the main skeleton.
Examples of the silicone resin include straight silicone varnish KR282 (manufactured by Shin-Etsu Chemical Co., Ltd.), straight silicone varnish KR271 (manufactured by the company), straight silicone varnish KR311 (manufactured by the company), modified silicone varnish KR211 (manufactured by the company), and silicone alkyd varnish. Commercial products such as (manufactured by the company) and silicone epoxy varnish ES100N (manufactured by the company) can be used.
As the silica sol, for example, a silica sol obtained by hydrolyzing ethyl silicate or the like, a colloidal silica sol, or the like can be used.

The amount of the silica-forming material and the metal resinate in the decorative layer-forming coating material can be appropriately adjusted according to the above-described Mn amount and / or Co amount with respect to the silica amount in the silica film after baking. The decorative layer-forming coating material can contain a metal resinate other than Mn resinate and Co resinate as long as the effects of the present invention are not impaired.
Further, the amount of the inorganic pigment in the decorative layer forming coating can be appropriately adjusted according to the color tone of the decorative layer to be formed. Specifically, the amount of the inorganic pigment can be, for example, in the range of 150 to 400 parts by mass with respect to 100 parts by mass of the silica-forming material (solid content).

Moreover, it is preferable that the decoration layer forming coating material further contains an organic binder (thickening resin). In this case, it becomes possible to adjust the viscosity of the coating material for forming a decorative layer, and it becomes easy to apply the coating material for forming a decorative layer to a glass plate during baking. As the organic binder, a resin that is easier to burn than the silica-forming material and is compatible with the silica-forming material can be used. The decorative layer-forming coating material can further contain an organic solvent. As the organic solvent, a solvent in which the silica-forming material can be dissolved can be used. The addition amount of the organic binder and the organic solvent can be appropriately adjusted in consideration of the viscosity of the decorative layer forming coating material.
The organic components in the decorative layer forming paint such as the organic binder, the organic solvent, the resin component in the silica forming material, the sol component, and the resin component of the metal resinate can be eliminated when the decorative layer forming paint is baked. .

  When the baking temperature of the decorative layer-forming paint is too low, the organic components remain, and the strength of the decorative layer generated after baking may be reduced. If the baking temperature is too high, the inorganic pigment in the decorative layer-forming coating material reacts with the silica-forming material, and the strength of the decorative layer may be reduced due to the difference in expansion coefficient between the two. Therefore, the decoration layer is preferably formed by baking the coating material for forming the decoration layer at a temperature of 500 to 900 ° C. The baking time is preferably 2 to 60 minutes from the viewpoint of productivity. Moreover, the thickness of a decoration layer can be 0.2-5 micrometers, for example.

The light shielding layer can be formed of a black film that does not transmit light.
Various materials can be used for the light shielding layer as long as they are black heat-resistant films, and a laminate of two or more layers may be used.
As the light shielding layer, for example, a black metallic luster film can be formed. The metallic gloss film can be composed of a noble metal and / or a metal oxide. Examples of metal components of noble metals and metal oxides include Au, Pt, Pd, Rh, Ru, Bi, Sn, Ni, Fe, Cr, Ti, Ca, Si, Ba, Sr, Mg, Ag, Zr, and In. , Mn and the like. The metallic gloss film can be composed of any of these noble metals, metals, metal oxides, or combinations thereof. When forming a metallic glossy film, the thickness is preferably 2 μm or less in order to prevent an increase in cost. If the light shielding property can be obtained, the thickness of the metallic gloss film is preferably as small as possible.

  The metallic gloss film is made of a metal such as Au, Pt, Pd, Rh, Ru, Bi, Sn, Ni, Fe, Cr, Ti, Ca, Si, Ba, Sr, Mg, Ag, Zr, In, and Mn. It can be formed by baking a diluted solution of an organometallic compound. These dilute solutions of organometallic compounds may be used alone or in combination at a desired ratio. The baking temperature of the diluted solution of the organometallic compound can be set to 600 to 900 ° C., for example.

In addition, the light shielding layer is preferably made of a silica film or a heat resistant resin film in which a black inorganic pigment is dispersed from the viewpoint that it can be produced at low cost and is excellent in heat resistance and light shielding properties.
In the case of forming a silica film in which a black inorganic pigment is dispersed, a light shielding layer coating material containing the silica forming material and the black inorganic pigment can be baked. As the silica-forming material, a silicone resin and / or silica sol can be used in the same manner as the decorative layer described above. Examples of the black inorganic pigment include Cr—Fe oxide, Cu—Cr—Mn oxide, Co—Mn—Cr—Fe oxide, Co—Ni—Cr—Fe oxide, Co A -Ni-Cr-Fe-Mn-based oxide or the like can be used. As the black inorganic pigment, a commercially available product can be used specifically, and the blending ratio can be appropriately adjusted according to the light shielding property of the light shielding layer. In addition, since these black inorganic pigments are generally composed of particles having a spherical shape or a shape close to a spherical shape, the light shielding layer containing the black inorganic pigment may have low adhesion to the decorative layer. Therefore, an additive composed of scaly particles such as mica can be added to the light shielding layer together with the black pigment. As such an additive, for example, the above-mentioned pearlescent pigment can be used in addition to a mineral such as mica. In addition, an organic solvent, an organic binder, or the like can be added to the coating material for the light shielding layer.

  In addition, when forming a heat-resistant resin film in which a black inorganic pigment is dispersed as a light-shielding layer, it contains at least a heat-resistant resin raw material that is cured by heating during baking to generate a heat-resistant resin, and a black inorganic pigment The shading paint can be baked. As the heat resistant resin, a silicone resin, a polyimide resin, a polyamide resin, a fluororesin, or a composite thereof can be used. As the black inorganic pigment, those described above can be used, and the blending ratio thereof can be appropriately adjusted according to the light shielding property of the light shielding layer.

  When a silica film or a heat-resistant resin film in which the above-described black inorganic pigment is dispersed is formed as the light shielding layer, the thickness of the light shielding layer can be set to 1 to 50 μm, for example. If the thickness is too large, the cost increases. If the thickness is too small, the light shielding effect may be insufficient. In addition, a silica film and a heat-resistant resin film can be laminated as the light shielding layer. Furthermore, the above-mentioned metallic glossy film can be formed between the silica film or the heat-resistant resin film and the decorative layer.

  Moreover, the said glass top plate for gas cookers has the opening part for heat sources which penetrates the plate-shaped glass top plate for gas cookers in the thickness direction. The opening for heat source can be formed in the glass plate in advance, and the decorative layer and the light shielding layer described above can be formed on the glass plate having the opening for heat source. In addition, the heat source opening may be formed after the decorative layer and the light shielding layer are formed on the glass plate.

Example 1
Next, the Example of the glass top plate for gas cookers is described using FIGS. As shown in FIGS. 1-3, the glass top plate 1 for gas cookers of this example is a glass plate 2 made of transparent low-expansion glass ceramics, a decorative layer 3 laminated on the back surface 22 side thereof, and a top thereof. And a laminated light shielding layer 4. The glass plate 2 is made of lithium aluminosilicate glass, and the main crystal phase is formed by depositing β-quartz solid solution. Specifically, as the glass substrate 2, a product name “Neoceram N-0” (hereinafter referred to as “Neoceram N-0”) manufactured by Nippon Electric Glass Co., Ltd. having a thermal expansion coefficient of −1 × 10 ⁻⁷ / ° C. (30 to 380 ° C.). N-0 ").

  As shown in FIGS. 2 and 3, the decorative layer 3 includes a silica film 31 and a number of pearl pigments 32 dispersed in the silica film 31. The silica film 31 is mainly composed of silica and contains cobalt oxide. The pearl tone pigment 32 includes a scale-like inorganic pigment 321 made of mica and a pearl tone coating 322 made of titanium oxide covering the pigment. At least part of the silica present in the silica film 31 forms Si—O—Si bonds (not shown) with at least part of the silanol groups present on the surface of the glass plate 2. In addition, at least a part of the silica present in the silica film 31 forms a Si—O—Ti bond (not shown) with at least a part of Ti present in the pearly coat 322 of the pearlescent pigment 32. Yes. The decorative layer 3 is formed by baking a decorative layer forming paint containing a silicone resin, a pearl pigment, and a Co resinate.

  As shown in FIGS. 2 and 3, the light shielding layer 4 includes a silica film 41, and a large number of black inorganic pigments 42 and pearlescent pigments 43 dispersed in the silica film 41. The light shielding layer 4 is formed by baking a coating material for a light shielding layer containing a silicone resin, a commercially available black inorganic pigment, a pearly pigment, and an organic solvent.

  Moreover, as shown in FIG.1 and FIG.2, the plate-shaped glass top plate 1 for gas cookers has the opening part 11 for heat sources which penetrates this in the thickness direction. This heat source opening 11 is an opening for exposing the flame of the burner arranged inside the gas cooker to the cooking surface side, and an object to be heated such as a pan is arranged around the heat source opening 11. Five virtues (not shown) are set up.

Next, the manufacturing method of the glass top plate 1 for gas cookers of this example is demonstrated.
Specifically, first, mica powder was suspended in a dilute titanic acid aqueous solution to obtain a suspension. This suspension was heated to a temperature of 70 to 100 ° C. to hydrolyze the titanium salt to precipitate hydrated titanium oxide on the surface of the mica powder. Thereafter, the mica powder was fired at a temperature of 700 ° C to 1000 ° C. As a result, a pearly pigment 32 formed by coating a pearly coating 322 made of titanium oxide on an inorganic pigment 321 made of mica was obtained (see FIG. 3).

  Next, 17.5 parts by mass of a pearl pigment, 17.5 parts by mass of a silicone resin (straight silicone varnish “KR282” manufactured by Shin-Etsu Chemical Co., Ltd.), 60 parts by mass of an organic binder (ethyl cellulose), and Co-containing A paste-like decorative layer-forming coating material was prepared by kneading 5 parts by mass of Co resinate having an amount of 12% by mass. Next, a paste-like coating material for forming a decorative layer is formed on the entire surface of one side 22 of the glass plate 2 having a thickness of 4 mm made of translucent low expansion glass ceramics (N-0) by screen printing using a stainless steel 250 mesh screen. Was applied (see FIGS. 2 and 3). The glass plate 2 is previously provided with a heat source opening 11 that penetrates the glass plate 2 in the thickness direction. The heat source opening 11 can also be formed after the formation of a decoration layer and a light shielding layer, which will be described later.

  Next, the glass layer 2 to which the decorative layer forming coating material was applied was baked at a temperature of 800 ° C. so that the decorative layer forming coating material was sintered and baked onto the glass plate 2. Thus, the decoration layer 3 was formed in the back surface 22 side of the glass substrate 2 (refer FIG.2 and FIG.3). When the thickness of the decorative layer 3 was measured with a film thickness meter, the thickness was 1.2 μm.

  Next, 60 parts by mass of a silicone resin (straight silicone varnish “KR311” manufactured by Shin-Etsu Chemical Co., Ltd.), 25 parts by mass of a black inorganic pigment, 5 parts by mass of a pearl pigment, and 10 parts by mass of an organic solvent The paint for mixing and forming the light shielding layer 4 was produced. As the pearl pigment, the same pigment as that used for forming the decorative layer 3 was used. A commercially available product was adopted as the black inorganic pigment. The paste-like paint was applied onto the decorative layer 3 by screen printing using a stainless steel 250 mesh screen, and baked at a temperature of 400 ° C. Thereby, the light shielding layer 4 was formed on the decoration layer 3 (refer FIG.2 and FIG.3). Thus, the glass top plate 1 for gas cookers which has the glass plate 2, the decoration layer 3 laminated | stacked on the back surface side, and the light shielding layer 4 laminated | stacked on it was produced.

As shown in FIG. 1 to FIG. 3, the glass top plate 1 for a gas cooker of this example has at least one metal selected from manganese oxide, cobalt oxide, and a composite oxide of Mn and Co with silica as a main component. The decorative layer 3 having an excellent denseness has a silica film 31 containing an oxide and an inorganic pigment 32 dispersed in the silica film 31. Therefore, even if, for example, the squeezed juice is attached from the cooking surface 21 side through the heat source opening 11 to the back surface 22 of the glass top plate for the gas cooker, the end surface 110 of the heat source opening 11, etc. And the like can be prevented from penetrating into the decorative layer 3 and forming a cooking spot. Moreover, even if the spilled juice adhering to the back surface 22 of the glass top plate 1 for a gas cooker or the end surface 110 of the opening 11 for the heat source is heated and gasified, it is possible to suppress the penetration into the decorative layer 3. It can suppress that a cooking spot will be formed.
That is, the glass cooker glass top plate 1 can exhibit excellent design properties of the decorative layer 3 and can suppress the occurrence of cooking spots. Moreover, the light shielding layer 4 can serve to conceal the internal structure of the gas cooker and can make the above-mentioned cooking stains inconspicuous.
Therefore, the glass top plate 1 for gas cookers of this example can maintain the excellent designability of the decoration layer 3 over a long period of time.

In this example, a pearl pigment 32 is used as the inorganic pigment in the decorative layer 3. In this case, the glass top plate 1 for a gas cooker can exhibit a pearly color tone having a glossy feeling and exhibit more excellent design. In addition, the pearl-like decorative layer 3 tends to be noticeable in cooking stains. However, the glass top plate 1 for the gas cooker of this example has the dense decorative layer 3 as described above. Even if it has the easy pearl-like decoration layer 3, formation of a cooking spot can fully be suppressed.
In the shielding layer 4 of this example, not only the black inorganic pigment 42 but also scaly particles (pearl pigment 43) are dispersed. Therefore, the adhesion of the shielding layer 4 is improved.

  In this example, by using Co resinate, the decorative layer 3 having the silica film 31 containing cobalt oxide and the pearl-like pigment 32 dispersed in the silica film 31 was formed (see FIG. 3). . By using Mn resinate instead of Co resinate, a decorative layer having a silica film containing manganese oxide and a pearl-like pigment dispersed in the silica film can be formed. Also in this case, the same effect as the case where the above-described Co resinate is used can be obtained.

(Experimental example)
In this example, the type and amount of the metal resinate are changed to form a decorative layer on a glass plate, and the formation of cooking spots is evaluated.
Specifically, first, the same glass plate (“N-0”) as in Example 1 was prepared. Next, a pearly pigment, a silicone resin, an organic binder, and a metal resinate were kneaded to prepare a paste-like coating material for forming a decorative layer. The same pearl-like pigment, silicone resin, and organic binder as those used in Example 1 were used. As the metal resinate, in addition to the same Co resinate as in Example 1, Mn resinate with an Mn content of 8% by mass, Ti resinate with a Ti content of 15% by mass, or an Ag content of 28.5% by mass. Of Ag resinate was used. In this example, 13 kinds of paints were prepared by mixing pearl pigment, silicone resin, organic binder, and metal resinate at the blending ratio shown in Table 1 described later. One of these is a paint that does not contain a metal resinate (see Table 1).

Next, a decorative layer and a light shielding layer were formed on the glass plate in the same manner as in Example 1 except that the above-described coating materials for forming the decorative layer were used. Thus, 13 types of test plates (samples E1 to E10 and samples C1 to C3) for glass top plates for gas cookers were obtained.
Samples E1 to E5 are test plates for a glass top plate having a silica film containing silica as a main component and containing cobalt oxide as a decorative layer, and a pearl pigment dispersed in the silica film. Samples E6 to E10 are test plates for a glass top plate having a silica film containing silica as a main component and containing manganese oxide as a decorative layer, and a pearl pigment dispersed in the silica film.
Sample C1 is a glass top plate test plate having a silica film made of silica as a decorative layer and a pearlescent pigment dispersed in the silica film. Sample C2 is a test plate for a glass top plate having, as a decoration layer, a silica film containing silica as a main component and containing titanium oxide, and a pearlescent pigment dispersed in the silica film. Sample C3 is a test plate for a glass top plate having, as a decoration layer, a silica film containing silica as a main component and containing silver and a pearl pigment dispersed in the silica film.

  About the test plate of each sample, the amount (mass part) of the metal element (Co, Mn, Ti, Ag) derived from the metal resinate with respect to 100 parts by mass of silica in the silica film was measured by X-ray photoelectron spectroscopy (XPS). In XPS, “PHI5000” manufactured by ULVAC-PHI Co., Ltd. was used. The results are shown in Table 1.

Next, the following cooking spot test was implemented about each sample E1-E10 and sample C1-C3.
"Cooking spot test"
These were mixed in sake: soy sauce: mirin: oil = 1: 1: 1: 1 (volume ratio at a temperature of 25 ° C.) to prepare a cooking juice test solution. Using a dropper, the test solution was hung on the back surface (formation surface of the decoration layer and light shielding layer) side of each sample (samples E1 to E10 and samples C1 to C3) to form a liquid reservoir having a diameter of about 1 cm. Next, each sample coated with the test solution was heated in a kiln having a temperature of 250 ° C. for 1 hour.

And the color difference (DELTA) E of the part which apply | coated the test liquid after a cooking spot test, and the part which is not apply | coated was measured from the cooking surface (surface on the opposite side to the formation surface of a decoration layer and a light shielding layer). The color difference ΔE was determined by the following equation (1).
ΔE = √ (L ₁ −L ₀ ) ² + (a ₁ −a ₀ ) ² + (b ₁ −b ₀ ) ² Formula (1)
Here, each variable is a value measured by a spectrocolorimeter (“SP60” manufactured by X-Rite Co., Ltd.), and all of L ₀ , a ₀ , and b ₀ are the portions where the test solution is not applied. L ₁ , a ₁ , and b ₁ are all values measured at the portion where the test solution was applied. The color difference ΔE of each sample is shown in Table 1 and FIG. In addition, the horizontal axis in FIG. 4 is a metal amount (mass part) derived from the metal resinate with respect to 100 parts by mass of silica in the decorative layer (silica film), and the vertical axis is the color difference ΔE.
Moreover, the digital camera photograph from the cooking surface (surface in which the decoration layer and the light shielding layer are not formed) after the cooking spot test is shown in FIG. 5 (samples E1 to E3 and samples E6 to E8) and FIG. 6 (samples C1 to C1). C3).

  As can be seen from Table 1 and FIG. 4, Samples E1 to E10 have a smaller color difference ΔE than Samples C1 to C3, and the formation of cooking spots is suppressed. Samples E1 to E10 had a pearly decorative layer and exhibited excellent design properties. That is, by using Co resinate and Mn resinate as the metal resinate, a decorative layer having a silica film containing cobalt oxide and manganese oxide is formed. As a result, while maintaining the excellent design of the decorative layer, the cooking stain is maintained. It can be seen that the formation of can be suppressed. From the photographs of FIGS. 5 and 6, by using Co resinate and Mn resinate (samples E1 to E10), when metal resinate is not used (sample C1) or when other metal resinates are used (sample C2 and It can be seen that the cooking spots are less noticeable compared to sample C3). In the decorative layer, the amount of Mn and Co with respect to 100 parts by mass of silica contained in the silica film is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, further preferably 5 parts by mass or more, and 12 parts by mass. The above is more preferable. By increasing the amount of Mn and the amount of Co, the AA class tolerance, that is, a level at which slight color difference is felt in the adjacent color comparison, up to the allowable color difference range including instrumental differences between general colorimetric instruments. Cooking spots can be made inconspicuous.

DESCRIPTION OF SYMBOLS 1 Glass top plate for gas cookers 11 Opening part for heat sources 2 Glass plate 22 Back surface 3 Decoration layer 4 Light shielding layer

Claims (6)

In a glass top plate for a gas cooker having a glass plate, a decorative layer having a thickness of 0.2 to 5 μm laminated on the back side of the glass plate, and a light shielding layer laminated on the decorative layer,
An opening for a heat source that penetrates the glass top plate for the gas cooker in the thickness direction;
The decoration layer is composed of silica as a main component, and includes a silica film containing at least one metal oxide selected from manganese oxide, cobalt oxide, and a composite oxide of Mn and Co, and dispersed in the silica film. Inorganic pigments,
In the decoration layer, the amount of Mn and / or Co in the metal oxide contained in the silica film is 0.5 to 50 parts by mass with respect to 100 parts by mass of silica. Glass top plate.   The glass top plate for a gas cooker according to claim 1, wherein the inorganic pigment is a white pigment or a silver pigment.   The glass top plate for a gas cooker according to claim 1 or 2, wherein the inorganic pigment is a pearl pigment.   The decorative layer is formed by baking a paint for forming a decorative layer containing at least a silica-forming material composed of a silicone resin and / or silica sol, an inorganic pigment, and a metal resinate composed of Mn resinate and / or Co resinate. The glass top plate for a gas cooker according to any one of claims 1 to 3.   The glass top plate for a gas cooker according to claim 4, wherein the decoration layer is formed by baking the coating material for forming the decoration layer at a temperature of 500 to 900 ° C.   The glass top plate for a gas cooker according to any one of claims 1 to 5, wherein the light shielding layer is made of a silica film or a heat resistant resin film in which a black inorganic pigment is dispersed.