JP5338304B2 - Glass top plate for heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass top plate for a heating cooker capable of sufficiently concealing structures inside the cooker even with a color of high brightness, enabling it to hardly discriminate a translucent part from a cooking face of the cooker when a light source is in non-luminous state, and enabling it to visually confirm the translucent part by emission of the light source when it is in a luminous state. <P>SOLUTION: The glass top plate for a heating cooker is provided with a substrate 2 made of translucent and low-expansion glass ceramics, a pearl-tone layer 3 formed on a rear side surface 22 that is an opposite side surface of the cooking face 21 on the substrate 2, a covering layer 4 formed on the pearl-tone layer 3, a shading part 6 composed of a protective layer 61 made of resin containing inorganic pigments arranged on the covering layer 4, and the transparent part 5 composed of a transparent resin layer 51 made of transparent resin arranged on the covering layer 4. It is so structured that the translucent part 5 transmits light from the light source 81 arranged under the glass top plate 1, and the shading part 6 shields the light from the light source 81. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a glass top plate for a cooker that is disposed on an upper portion of a heating cooker.

  In recent years, with the spread of all-electric homes, the demand for electromagnetic cookers continues to expand. In such a background, the electromagnetic cooker has evolved into one having various functions, and the structure inside the apparatus has become complicated accordingly. For such reasons, it has become necessary to conceal the structure inside the electromagnetic cooker more than ever for the top plate for the electromagnetic cooker.

  Further, a glass touch type top surface operation type electromagnetic cooker that enables main operations on the cooking surface of the electromagnetic cooker has been widespread. Then, the top operation of the glass touch method can be performed, for example, by forming a carbon electrode, a wiring circuit, or the like on the back side surface of the substrate in a portion to be a switch.

  And as a method of visually recognizing the switch of the top surface operation, a portion having a light-transmitting property is provided around a dark and highly light-shielding carbon electrode, and a light source disposed inside the electromagnetic cooker is caused to emit light. There is a demand for a method in which a switch forming portion appears and is identified only when light is emitted from a light source by irradiating a portion having translucency and floating.

  Further, not only the switch forming portion but also the display portion of the thermal power and the timer has a structure that transmits light from the light source provided below the glass top plate. For this reason, there is a need for a system that makes these portions appear and be identified only when the light source emits light.

  And as a glass top plate that can conceal the structure inside the electromagnetic cooker and realize the recognition method such as the above-described switch forming part, a dark raster layer is formed on the back side of the glass substrate, Some have a configuration in which a carbon electrode is provided in a necessary portion on top, or a light shielding layer is provided in a portion other than a display portion or the like.

This glass top plate can conceal an internal structure by providing a dark raster layer.
Further, the portion where the carbon electrode and the light shielding layer are not formed can sufficiently transmit the light when the light source disposed under the glass top plate emits light. And the formation part (top switch part of a top surface operation) of a carbon electrode and the formation part of a light shielding layer do not permeate | transmit the light from a light source by the high light-shielding property of a carbon electrode and a light shielding layer. For this reason, when the light source emits light, the carbon electrode and the unshielded portion of the light-shielding layer emerge, and the formation position of the carbon electrode, the display portion, and the like can be clearly identified.

  Furthermore, from the cooking surface side of the glass top plate, there is no color difference between the portion where the carbon electrode or light shielding layer and the dark raster layer overlap and the portion where only the dark raster layer is formed, and the light source When the light is not emitted, it is difficult to distinguish between the two, and the switch portion, the display portion, and the like can be identified only when the light source emits light.

Japanese Patent No. 3758445

However, with the above glass top plate configuration, only dark colors can be expressed, and it is difficult to express color tone with high brightness such as white.
On the other hand, in kitchen counters where electromagnetic cookers are placed, there is a great demand for white systems, and there is a glass top plate for heating cookers with high brightness such as white that expresses a pearl effect that can be harmonized with the counter color. It is strongly desired. However, from the above situation, this cannot be met.

  As a glass top plate for heating cooker of pearl tone silver gray system, it is possible to demonstrate a pearl tone effect with a configuration in which a pearl tone paint layer is formed on a translucent low expansion glass ceramic in Patent Document 1, and a translucent low expansion A pearl-tone glass ceramic having the inherent strength of glass ceramic is described. Further, Patent Document 1 describes that a light shielding property for concealing the structure inside the electromagnetic cooker can be obtained by providing a light shielding layer on the pearl color paint layer.

  In the configuration in which the pearl tone paint layer is formed on the translucent low expansion ceramic of Patent Document 1, when a carbon electrode or a wiring circuit is formed on the pearl tone paint layer, a pearl tone effect is obtained. The design function that the concealment property by the paint layer is weak, the concealment property of the structure inside the cooker is insufficient, or the formation pattern such as the carbon electrode is transmitted, and the switch is made visible through the light. Decreases.

  And in the structure which provides the light shielding layer on the said pearl color paint layer of the said patent document 1, the design expression which has a brightness | luminance of a silver tone is attained, and the structure inside a cooking appliance is reduced by reducing the light transmittance. A sufficient light-shielding property can be obtained to conceal the light and prevent the formation pattern of the carbon electrode or the like from being transmitted. However, when such a structure is adopted, even when the light source is caused to emit light, it is difficult to transmit the light, so that the design function of allowing the switch to be visually recognized by transmitting the light is deteriorated. There is.

In addition, in the case of having a configuration in which a light shielding layer is provided on the pearl color paint layer, concealment of the structure inside the cooker, prevention of transmission of a formation pattern such as a carbon electrode, and transmission of light during light emission of the light source In order to obtain visibility, the pearl-colored paint layer or the light-shielding layer is formed discontinuously in the vicinity of the carbon electrode or in a portion where light such as a display part of a thermal power or a timer is desired to be transmitted. A method of transmitting light to a portion where the light shielding layer is not formed (light transmitting portion) is also conceivable.
However, in this case, the light-transmitting portion and other portions have a color difference, and even when the light source is not emitting light, the position of the light-transmitting portion can be recognized, which is inferior in design. There is a problem.

  And now, a combination of a configuration in which a light-shielding layer is provided on a pearl-colored paint layer and a configuration in which the above-described dark color raster layer is provided, and a portion including a light transmitting portion such as the vicinity of a carbon electrode or a display portion of a thermal power or timer Provides a top plate having a structure in which a dark raster layer is formed in a strip shape, and a light shielding layer is provided on a pearl-colored paint layer in a portion where the other internal structures are required to be concealed. Thereby, the visibility of the translucent part by the concealment of the structure inside a cooking appliance, the permeation | transmission prevention of formation patterns, such as a carbon electrode and a light shielding layer, and the permeation | transmission of the light at the time of light emission of a light source can be acquired. However, even if it is partial, since the dark color raster layer is formed, the design of the entire glass top plate is lowered, for example, the quality of the pearl tone is lowered.

  The carbon electrode layer and the wiring circuit are generally formed using a carbon paste obtained by kneading a conductive material and a heat resistant resin. Therefore, when a carbon electrode or the like is formed on a painting layer having a high color tone, printing and curing (curing) at the time of formation may cause a gap between a formed portion and a non-formed portion of the carbon electrode layer. Some color difference due to wettability described later occurs. For this reason, even when the light source is not emitting light, there is a problem that the switch portion is conspicuous due to the color difference. Further, although the color difference due to the wettability will be described later, it is a problem that also occurs in the light shielding layer provided to conceal the structure and the like inside the cooker.

  Light scattering does not occur in the part where the carbon electrode layer or light shielding layer is formed, but light scattering occurs in the part where the carbon electrode layer or light shielding layer is not formed. A color difference is produced. The color difference referred to here is the color difference due to wettability.

  For this reason, the entire glass top plate, including the light-transmitting parts such as the switch forming part and the display part of the thermal power and timer, is expressed with a high color tone, and the structure inside the cooker can be sufficiently concealed. There is a demand for a glass top plate for a cooking appliance having a design function that only a translucent portion appears.

  The present invention has been made in view of such conventional problems, and can sufficiently conceal the structure inside the cooker even in a light color tone, and when the light source is not emitting light. The glass top plate for a heating cooker is characterized in that it is difficult to identify the translucent part from the cooking surface and that the translucent part can be clearly seen by the light emission of the light source when the light source emits light. Is.

The present invention, in a glass top plate disposed on the top of the heating cooker,
A substrate made of translucent low-expansion glass ceramics, a pearly layer formed on the back side opposite to the cooking surface of the substrate, and a coating layer formed on the pearly layer Have
A light shielding part constituted by disposing a protective layer made of a resin containing an inorganic pigment on the coating layer;
A translucent part constituted by disposing a transparent resin layer made of a transparent resin on the coating layer;
The visible light transmittance of the translucent part is 3.5% or more,
In the translucent part, it is configured to transmit light from a light source disposed below the glass top plate, and to shield light from the light source in the light shielding part ,
Having an electrode part configured by disposing a carbon electrode layer on the coating layer;
The electrode part is a switch part for the top operation of the glass top plate,
The translucent part is for displaying the switch part,
In the glass top plate for a heating cooker , the color difference ΔE between the light transmitting portion and the light shielding portion on the cooking surface of the substrate when the light source is not emitting light is 1.5 or less. ).

  The glass top plate for a heating cooker according to the present invention is configured to have all of the above-described requirements, so that even if it has a highly light color tone such as a white system that has been strongly desired in recent years, This structure can be sufficiently concealed, and the light-transmitting portion can be revealed only during light emission, which can be particularly excellent in design.

  The said glass top plate for heating cookers can provide a pearl tone color tone to the glass top plate for heating cookers by providing a pearl tone layer on the back side surface of the said board | substrate. The transmittance and brightness can be adjusted by the composition, thickness, etc. of the pearl tone layer.

  Moreover, a coating layer is laminated on the pearl tone layer. The said coating layer suppresses the permeation | transmission of the deep color of the said protective layer, ensuring translucency, without inhibiting the texture of the said pearl tone layer. Moreover, the said coating layer also has a role which protects the said pearl tone layer.

In addition, a light transmitting part that transmits light from a light source disposed below the top plate and a light shielding part that blocks light from the light source are provided.
The translucent part is a part that transmits light from a light source disposed below the top plate. That is, it is a portion that stands out so that it can be identified when the light source emits light.
Therefore, the translucent part must be configured to transmit the light from the light source, and the pearl tone layer and the covering layer must be laminated so as to transmit the light from the light source. Don't be.
Further, the light source may be arranged in any manner as long as it is arranged below the top plate so as to irradiate the light transmitting part.

  Moreover, the said light shielding part is comprised by arrange | positioning the protective layer which consists of resin containing an inorganic pigment on the said coating layer. Thereby, it can prevent that the light from a light source is scattered in parts other than a translucent part. Moreover, it has the effect of hiding the said structure by forming in the part etc. in which the structure inside a cooking appliance is arrange | positioned below, and providing light-shielding property. In addition, in an electromagnetic cooker with high function, there are some in which the internal parts are close to the glass top plate and there is only a narrow gap. In such a case, for example, there is a possibility that a wear mark may be generated in the pearl tone layer or the coating layer laminated on the back side surface of the glass top plate due to vibration during transportation. And the said protective layer also has the protective effect which suppresses the damage of the back side surface of the said glass top plate for heating cookers.

Moreover, the said light-shielding part is comprised by arrange | positioning the protective layer which consists of resin containing an inorganic pigment on the above-mentioned coating layer. A color difference due to wettability is generated between the protective layer forming portion and the protective layer non-forming portion due to the print curing at the time of forming the protective layer.
As described above, the wettability is a color difference caused by light scattering not occurring in the protective layer forming portion and light scattering occurring in the protective layer non-forming portion. And when the color difference has arisen, when it observes from the cooking surface side, it will be in the state changed to the color tone which the said protective layer formation part (light-shielding part) was wet.

  And the said translucent part is comprised by arrange | positioning the transparent resin layer which consists of transparent resin on the said coating layer. Therefore, by forming a transparent resin layer on the coating layer, wettability can be imparted to the translucent part without reducing translucency or improving translucency. By imparting wettability to the light-transmitting part as well as the light-shielding part, the color difference from the protective layer forming part (light-shielding part) can be reduced. That is, when the light source is not emitting light, the color difference between the translucent part and the light-shielding part is small, making it difficult to identify the translucent part from the cooking surface. On the other hand, when the light source emits light, only the translucent part transmits light and emerges, so that the translucent part can be clearly seen.

  In addition, since the pearl tone layer itself has a certain degree of light-shielding property, the texture of the pearl tone effect is hindered even if the coating layer and the protective layer may be affected by some color. There is nothing. Therefore, the glass top plate for a heating cooker can realize a pearly color with relatively high brightness due to the pearly effect of the pearly layer.

  Thus, according to the present invention, the structure inside the cooker can be sufficiently concealed even when the color tone has high brightness, and when the light source is not emitting light, the translucent part is removed from the cooking surface. The glass top plate for a cooking device can be provided in which the light-transmitting portion can be clearly seen by the light emission of the light source when the light source emits light.

As described above, the glass top plate for a heating cooker according to the present invention includes a substrate made of translucent low-expansion glass ceramics, and a pearl tone formed on the back side surface of the substrate opposite to the cooking surface. And a coating layer formed on the pearl tone layer.
The translucent low expansion glass ceramic is not particularly limited as long as it is translucent and has a low expansion coefficient. For example, there is one in which a β-quartz solid solution is precipitated in the main crystal phase.

  The crystallinity of the translucent low expansion glass ceramics on which the β-quartz solid solution is deposited is, for example, about 70% by volume 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.

When the pearl tone layer is not formed, there is a problem that a pearl tone effect cannot be exhibited and a color tone with high brightness cannot be realized.
The pearl tone layer may be composed of only one layer, but may be laminated in two or more layers. And in order to express the pearl tone effect by a pearl tone layer strongly, it is preferable that the said pearl tone layer consists of two layers.
Further, the pearl tone layer is not necessarily provided on the entire back surface.
Moreover, it is preferable that the film thickness of the said pearl tone layer exists in the range of 3-30 micrometers.

  When the film thickness of the pearl tone layer is less than 3 μm, the transmittance may be increased, and the translucent part cannot have a sufficient hiding power. There is a risk that it may be difficult to conceal, and it may be difficult to prevent transmission of the protective layer and the carbon electrode layer described later when the light source is not emitting light. On the other hand, when the film thickness of the pearl tone layer exceeds 30 μm, the pearl tone layer may be peeled off due to a difference in thermal expansion. The film thickness of the pearl tone layer is more preferably 5 to 15 μm.

  Further, in the case where the covering layer is not formed, a protective layer is formed on the pearl tone layer, but dark color transmission of the protective layer cannot be suppressed. Even if the transparent resin layer is formed, there is a problem that the color difference between the light transmitting portion and the light shielding portion when the light source is not emitting light and a carbon electrode layer described later cannot be eliminated.

Moreover, the said light shielding part is comprised by arrange | positioning the protective layer which consists of resin containing an inorganic pigment on the said coating layer.
When not providing the said protective layer, there exists a possibility that the concealment of the structure inside a cooking appliance may become inadequate. Moreover, it cannot prevent that the light from a light source is scattered in parts other than a translucent part, and there exists a possibility that the designability may be inferior.
Further, it is preferable that the light shielding part is formed in a desired pattern in a place that is easily affected by wear even if it is a part that does not need to shield light from the light source.
It is preferable that the protective layer is provided on the entire surface of the coating layer excluding the light transmitting portion and an electrode portion described later.

Moreover, the said translucent part is comprised by arrange | positioning the transparent resin layer which consists of transparent resin on the said coating layer.
As the transparent resin, a silicone resin, a phenol resin, a fluorine resin, a polyimide resin, a polyamide resin, or the like can be used.
In the transparent resin layer, the term “transparent” means that the light transmittance in a wavelength region of 380 to 780 nm is 65% or more from JIS R 3106.

  And if it is a range which satisfies the definition of the above-mentioned transparency, the above-mentioned resin may contain an inorganic pigment. Further, it is preferable that the amount of the inorganic pigment added is small, and if the inorganic pigment is not sufficiently dispersed when light is transmitted through the light transmitting portion, the inorganic pigment may appear as a foreign substance. The upper limit of the pigment addition amount is 20% by mass or less. The transparent resin layer preferably does not contain an inorganic pigment.

When the transparent resin layer is not disposed on the covering layer in the light transmitting part, a color difference is generated between the light transmitting part and the light shielding part, and the light transmitting part is identified even when the light source is not emitting light. There is a problem that it will be in a state of being.
Further, when the resin is not transparent, the transmittance of the light transmitting portion is reduced, and when the light source emits light, the light from the light source is difficult to pass through the light transmitting portion, and the visibility of the light transmitting portion is improved. There is a problem of lowering.
Moreover, there is no problem even if the transparent resin layer partially overlaps the protective layer and a carbon electrode layer described later.

The glass top plate for a heating cooker preferably has a color difference ΔE of 1.5 or less between the light transmitting portion and the light shielding portion on the cooking surface of the substrate when the light source is not emitting light .
In this case, particularly when the light source is not emitting light, the light transmitting portion can be made inconspicuous.

If the transparent resin layer is provided in the light transmitting part, it is possible to reduce the color difference between the light transmitting part and the light shielding part when the light source is not emitting light, compared to the case where the transparent resin layer is not provided. However, when the color difference ΔE exceeds 1.5, the color difference is not sufficiently reduced, and the light-transmitting portion may be easily recognized when the light source is not emitting light. Further, the color difference ΔE is 2.0. In the case where the light source is over, the switch part may be easily recognized from the cooking surface when the light source is not emitting light.
The color difference is a numerical value represented by ΔE = {(ΔL) ² + (Δa) ² + (Δb) ² } ^1/2 in the Lab surface dye.

Moreover, it is preferable that the visible light transmittance of the said translucent part is 3.5% or more .
In this case, in particular, the light transmitting part can be clearly recognized when the light source emits light.
In addition, the said visible light transmittance | permeability means the transmittance | permeability of the light in the wavelength range of 380-780 nm from JISR3106. Further, the transmittance of the translucent part is affected by the thickness of the overlapping of the pearl tone layer and the covering layer.

When the transmittance of the light is less than 3.5%, the light above SL source is not easily transmitted through the light transmitting portion during light emission of the light source, the visibility of the light transmitting portion at the time of light emission of the light source May decrease.
In view of the function of transmitting light at the time of light source emission, the visible light transmittance of the light-transmitting portion is preferably higher as long as the light transmittance is high. In view of the color difference, it is more preferably 5 to 15%.

Moreover, it is preferable that the visible light transmittance | permeability at the time of forming only a pearl tone layer and a coating layer in the said board | substrate is 3.5 to 15%.
When the visible light transmittance is less than 3.5% when only the pearl tone layer and the coating layer are formed on the substrate, the light from the light source is difficult to transmit through the light transmitting part when the light source emits light. There is a possibility that the visibility of the switch part for the top surface operation may be lowered. On the other hand, when the visible light transmittance exceeds 15%, the color difference ΔE between the light-shielding part and the light-transmitting part on the cooking surface exceeds 1.5, and even if a transparent resin layer is disposed on the light-transmitting part, the light-transmitting part The color difference between the light-shielding part and the light-shielding part cannot be eliminated, and the light-transmitting part may become noticeable when the light source is not emitting light.
The visible light transmittance when the pearl tone layer and the coating layer alone are formed on the substrate is more preferably 5 to 12%.

  And in order to implement | achieve the above-mentioned visible light transmittance | permeability, the visible light transmittance | permeability at the time of forming only the said pearl tone layer in the said board | substrate is 20-35%, and formed only the said coating layer in the said board | substrate. The visible light transmittance at that time is preferably 10 to 55%.

By providing the pearl tone layer having the specific transmittance, a pearl tone color having high brightness can be imparted to the top plate.
When the visible light transmittance when only the pearl tone layer is formed on the substrate is less than 20%, the lightness (L value) on the cooking surface may be less than 70, and the color tone is white. It may become difficult to exhibit (white color tone). In addition, the translucency required for the translucent part cannot be obtained, and when the light source emits light, the light from the light source becomes difficult to transmit through the translucent part, and the visibility of the switch unit may be reduced. . On the other hand, when the transmittance exceeds 35%, the light shielding property by the pearl layer is lowered, and the coating layer needs to have a light shielding property in order to have a sufficient hiding power in the light transmitting part. If the coating layer has light shielding properties, the brightness on the cooking surface may be less than 70, and it may be difficult to exhibit a white tone (white color tone).
The visible light transmittance when only the pearl tone layer is formed on the substrate is more preferably 20 to 30%.

In addition, by laminating the coating layer having the specific transmittance, the carbon electrode layer has a dark color transmission and the protection without impairing the texture of the pearl tone layer, while maintaining the translucency. Transmission of the dark color of the layer can be suppressed.
When the visible light transmittance is less than 10% when only the light shielding layer is formed on the substrate, the coating layer exhibits light shielding properties, and the lightness (L value) on the cooking surface may be less than 70. There is a possibility that it becomes difficult to exhibit a white tone (white color tone). In addition, when the light source emits light, the light from the light source is difficult to transmit through the light transmitting part, and the visibility of the light transmitting part is reduced. On the other hand, when the visible light transmittance when only the light shielding layer is formed on the substrate exceeds 55%, the visible light transmittance when the pearl tone layer and the coating layer are overlapped may exceed 15%. The color difference ΔE between the light-shielding part and the light-transmitting part on the cooking surface exceeds 1.5, and the function of the design surface that makes the switch part inconspicuous when the light source does not emit light may be deteriorated.
Further, it is more preferable that the visible light transmittance is 15 to 50% when only the coating layer is formed on the substrate.

Moreover, it is preferable to have the electrode part comprised by arrange | positioning a carbon electrode layer on the said coating layer .
Thereby, it can be made possible to deal with a glass touch type top surface operation type electromagnetic cooker that enables main operations on the cooking surface of the electromagnetic cooker.
The carbon electrode layer is not limited to the electrode of the switch portion for the top operation of the glass top plate, but also includes a wiring circuit and the like.

  The carbon electrode layer is generally formed using a carbon paste obtained by kneading a conductive material and a heat resistant resin. Then, when the carbon electrode layer is formed on the coating layer, a color difference due to wettability occurs between the carbon electrode layer forming portion and the carbon electrode layer non-forming portion due to the print curing at the time of formation, similar to the light shielding layer. . However, there is almost no color difference between the light-shielding part and the electrode part, and since the transparent resin layer is disposed in the light-transmitting part, the light-transmitting part, the light-shielding part, and the electrode part when the light source is not emitting light Can be difficult to identify.

  Further, when the light transmitting portion is provided in the vicinity of the electrode portion (switch portion), the light transmitting portion in the vicinity of the carbon electrode layer is raised so that the switch portion can be identified when the light source emits light. Therefore, when the light source is not emitting light, the electrode part (switch part) is not identified from the cooking surface, and the switch part appears only during light emission and has a design function that can be clearly seen. Can do.

Moreover, it is preferable that the lightness (L value) in the said cooking surface is 70 or more (Claim 2 ).
In this case, the glass top plate for a heating cooker can exhibit a white tone (white color tone).
Even if the lightness is less than 70, the structure inside the cooker can be sufficiently concealed, and when the light source is not emitting light, it is difficult to identify the translucent part from the cooking surface. In some cases, the object of the present invention can be achieved if the light-transmitting portion can be clearly visually recognized by the light emission of the light source. However, as described above, the conventional technology can only express dark colors, and it is difficult to express a color tone with a high brightness such as a white color. Therefore, the present invention has a high brightness such as a white color. It is particularly suitable for expressing color tone.
The lightness (L value) is a degree of lightness and darkness, and can be measured using, for example, a spectrocolorimeter X-rite SP60 manufactured by X-Rite.

The pearl tone layer has a pearl tone material content of more than 10% by mass and 30% by mass or less, a silicone resin or siliceous sol of 10% by mass to 30% by mass, and an organic binder of 40% by mass to 80% by mass. It is preferable that a pearl color paint having a weight of less than% by mass is fired with a picture on the substrate (claim 3 ).

In this case, by providing the pearl tone layer using the pearl tone paint having the specific composition, a sufficient pearl tone effect can be exhibited at low cost.
Since the said pearl color paint contains the said pearl-like material more than 10 mass% and 30 mass% or less, it can express sufficient pearl tone effect in the said glass top plate for cookers. Moreover, concealment power can also be provided.

  The pearl tone paint contains the specific amount of silicone resin or siliceous sol. These serve as a binding material for bonding between the pearl color paint and the substrate, and can be a pearl layer having excellent durability that can withstand an impact from a cooking surface, a thermal shock, or the like.

  Further, the specific amount of the organic binder contained in the pearl-colored paint imparts fluidity to the pearl-colored paint containing a relatively large amount of the pearl-colored material, and in the formation of the pearl-colored layer on the substrate, unevenness and It is possible to suppress defects such as scumming and obtain good paintability.

  That is, by adding a specific amount of the silicone resin or siliceous sol and the organic binder to the pearl tone paint, a large amount of pearl tone material can form a pearl tone layer that adheres well to the substrate. it can. Therefore, it has a sufficient pearl tone effect, has a hiding power, and has a strength with no practical problem.

  Moreover, when forming the said pearl tone layer using the said pearl tone paint, since it consists of a pearl tone material, a silicone resin or a siliceous sol, and an organic binder, it can obtain at low cost.

The pearl tone material is, for example, coated with an inorganic pigment with titanium oxide, zirconium oxide, iron oxide or the like. The color of the inorganic pigment may be any number, and the pearl tone material exhibits a color obtained by adding a pearl tone to the color.
The inorganic pigment is not particularly limited, but kaolin, talc, sericite, pyroferrite, natural mica, synthetic mica, aluminum oxide and the like are preferably used.

  Moreover, a well-known technique can be used for coating methods, such as a titanium oxide, a zirconium oxide, and an iron oxide. For example, when coating titanium oxide with mica as an inorganic pigment, the mica powder is suspended in a dilute titanic acid aqueous solution, heated to 70 to 100 ° C., and the titanium salt is hydrolyzed to mica powder. There is a method in which hydrated titanium oxide particles are deposited on the surface and then fired at a high temperature of 700 ° C to 1000 ° C.

  Moreover, when content of the said pearl tone material is 10 mass% or less, there exists a possibility that sufficient pearl tone effect cannot be exhibited. On the other hand, when the content of the pearl-like material exceeds 30% by mass, the amount of the organic binder decreases, and the viscosity as a paste deteriorates. There is a risk that problems such as unevenness and blurring may occur in film formation. Or there exists a possibility that content of the said silicone resin or siliceous sol may fall, and the adhesive force of a pearl tone layer and a board | substrate may fall remarkably.

The silicone resin refers to a polymer of an organosilicon compound having a siloxane bond as a main skeleton. If necessary, an organic solvent in which the silicone resin can be dissolved is used.
As the siliceous sol, for example, a silica sol obtained by hydrolyzing ethyl silicate or the like, a colloidal silica sol, or the like can be used.

  Further, when the content of the silicone resin or siliceous sol is less than 10% by mass, the adhesion between the pearly layer and the substrate may be significantly reduced. On the other hand, when the content of the silicone resin or siliceous sol exceeds 30% by mass, the silicone resin or siliceous sol may cover the pearl tone material, and the pearl tone effect may be reduced. Moreover, the ratio of the pearl-like material in a pearl-colored paint will fall, and there exists a possibility that sufficient pearl-like effect cannot be exhibited. In addition, since the amount of the organic binder is reduced and the viscosity as a paste is deteriorated, there is a possibility that problems such as unevenness and scumming may occur in the coating film formation on the translucent low expansion glass ceramic. is there.

  As the organic binder, for example, an acrylic resin, an amide resin, an alkyd resin, a cellulose resin, or the like can be used. Moreover, you may add an organic solvent as needed.

In addition, when the content of the organic binder is less than 40% by mass, a paste having fluidity cannot be obtained, and in the formation of a coating film on the translucent glass ceramic, problems such as unevenness and scumming occur. There is a possibility. In addition, the ratio of the pearl-like material increases, and as described above, there is a possibility that problems such as unevenness and blurring may occur in the coating film formation on the translucent low expansion glass ceramic. On the other hand, when the content of the organic binder is 80% by mass or more, a fluid paste can be obtained, but the ratio of the pearl-like material may be reduced, and the pearl-like effect may not be obtained. There is a possibility that the content of the resin or siliceous sol is lowered, and the adhesion between the pearly layer and the substrate is significantly lowered.
In addition, also when forming the said pearl tone layer in multiple layers, the said baking is sufficient once.

  Further, in order to adjust the color of the pearl tone material, an inorganic pigment may be added to the pearl tone paint in a weight of 50% or less with respect to the weight of the pearl tone material. However, when an inorganic pigment is contained, the content of the powder combining the pearly material and the inorganic pigment should not exceed 30% by mass.

Examples of the inorganic pigment include a white inorganic pigment, a black inorganic pigment, a gray inorganic pigment, a yellow inorganic pigment, a brown inorganic pigment, a green inorganic pigment, a blue inorganic pigment, and a pink inorganic pigment.
Specifically, examples of the white inorganic pigment include TiO ₂ , ZrO ₂ , ZrSiO ₄ , Al ₂ O ₃ , 3Al ₂ O ₃ -2SiO ₂ , and Al ₂ TiO ₅ .

Examples of the black inorganic pigment include Cr-Fe-based oxides, Co-Mn-Cr-Fe-based oxides, Co-Ni-Cr-Fe-based oxides, and Co-Ni-Cr-Fe-Mn-based materials. An oxide etc. are mentioned.
Examples of the gray inorganic pigment include Sn-Sb-based oxides and Sn-Sb-V-based oxides.

Examples of the yellow inorganic pigment include Sn-V oxides, Zr-V oxides, Zr-Si-Pr oxides, Ti-Cr-Sb oxides, and the like.
Examples of the brown inorganic pigment include Zn-Al-Cr-Fe-based oxides and Zn-Mn-Al-Cr-Fe-based oxides.

Examples of the green inorganic pigment include Ca—Cr—Si oxides, Cr—Al oxides, Co—Zn—Al—Cr oxides, and Zr—Si—Pr—V oxides. It is done.
Examples of the blue powder include Co—Al—Zn-based oxides, Co—Al-based oxides, and Zr—Si-based oxides.
Examples of the pink inorganic pigment include Mn—Al oxides, Ca—Sn—Si—Cr oxides, Sn—Cr oxides, and Zr—Si—Fe oxides.
These pigments can be mixed in an arbitrary ratio so as to obtain a desired color.

  When an inorganic pigment is contained in the pearl-colored paint, the content of the inorganic pigment is 7.5% at the maximum when the pearl-like material is 15%. When the content of the powder including the pearly material and the inorganic pigment is 30% by mass, the content of the inorganic pigment is 10% at the maximum.

And when making a pearl tone paint contain an inorganic pigment, when content of the said inorganic pigment exceeds 50%, there exists a problem that a pearl tone falls.
In addition, when the content of the powder combining the pearl tone material and the inorganic pigment exceeds 30% by mass, the content of the silicone resin or the siliceous sol is decreased, and the adhesion between the pearl tone layer and the substrate is reduced. Because the content of the organic binder is reduced and the viscosity of the paste is deteriorated, the coating film is formed on the translucent glass ceramic. There is a possibility that.

  In the present invention, a glass top plate that can be applied to a cooker with a relatively high brightness can be obtained by having the above-described configuration, but a pearl tone having a desired color can be obtained. It goes without saying that by using materials and inorganic pigments, various color tones can be expressed, not limited to white.

Moreover, it is preferable that the said coating layer apply | coats the dilute solution of an organometallic compound on the said pearl tone layer, and is baked (Claim 4 ).
In this case, not only the above-mentioned effect but also heat resistance can be imparted to the glass top plate for a heating cooker.

  Examples of the diluted solution of the organometallic compound include Au, Pt, Pd, Rh, Ru, Bi, Sn, Ni, Fe, Cr, Ti, Ca, Si, Ba, Sr, Mg, Ag, Zr, In, Examples include diluted solutions of organometallic compounds such as Mn, Zn, and Al. These dilute solutions of organometallic compounds may be used alone or in combination at a desired ratio.

Moreover, the said coating layer can be formed by apply | coating the diluted solution of the said organometallic compound on the said pearl tone layer, and baking. The application of the diluted solution of the organometallic compound is preferably performed by screen printing.
The coating layer may be fired simultaneously with the pearl tone layer, or may be separately fired after firing the pearl tone layer.

Further, the protective layer is preferably formed by a heat resistant resin and an inorganic pigment coated and baked (claim 5).
In this case, not only the above-mentioned effect but also heat resistance can be imparted to the glass top plate.

The protective layer is preferably formed by applying a paste made of a heat-resistant resin and an inorganic pigment on the coating layer and baking at 200 to 450 ° C.
The paste is preferably applied by screen printing.
Moreover, the said paste may contain the organic solvent as needed.

When the baking temperature is less than 200 ° C., the heat-resistant resin layer is hardly baked sufficiently, and the heat-resistant resin layer is easily peeled after baking, and the function as a protective layer may not be sufficiently exhibited. On the other hand, when the calcination temperature exceeds 450 ° C., the heat-resistant resin disappears and the protective effect may be lost.
The firing temperature is more preferably 250 to 400 ° C.

  The heat resistant resin is preferably a silicone resin, a phenol resin, a polyimide resin, a fluororesin, or a composite thereof. In this case, the above-described protective effect can be obtained particularly well.

Moreover, the above-mentioned inorganic pigment etc. can be used for the said inorganic pigment.
Moreover, it is preferable that content of an inorganic pigment is 50 mass% or less. When the content of the inorganic pigment exceeds 50% by mass, the content of the heat-resistant resin becomes insufficient, the adhesion may be lowered, and it becomes difficult to exhibit the above function.

Also, the carbon electrode layer is preferably formed by firing by applying a conductive carbon paste (claim 6).
The conductive carbon paste contains spherical and flaky graphite powder and acetylene black as a conductive material, and contains a polyester silicone resin as a vehicle, and the spherical graphite powder, flaky graphite powder, acetylene black, When the total content of the polyester silicone resin is 100 parts by weight, the conductive carbon paste contains 15 to 25 parts by weight of the spherical graphite powder, 15 to 25 parts by weight of the flaky graphite powder, and the acetylene. The conductive carbon paste having an average particle size of 10 μm to 20 μm is used for the spherical and scaly graphite powders containing 10 to 20 parts by weight of black and 40 to 55 parts by weight of the polyester silicone resin. preferable.

  In the wiring circuit of the touch operation panel of an electromagnetic cooker, it is assumed that the wiring circuit becomes hot. However, when the wiring circuit is formed using the conductive carbon paste, the characteristic of excellent heat resistance is maximized. Can be demonstrated.

In addition, in a touch operation panel of an electromagnetic cooker, a wiring circuit formed of carbon paste may be peeled off due to wear, but the conductive carbon paste has excellent adhesion, so that Rarely happen.
Further, the conductive carbon paste can be adhered with sufficient adhesion strength to a resin layer such as silicone.

The carbon electrode layer is preferably formed by applying a conductive carbon paste on the coating layer and baking at 200 to 450 ° C.
The conductive carbon paste is preferably applied by screen printing according to a necessary place such as an electrode or a wiring circuit.

Moreover, it is preferable that the painting glass decoration layer which consists of a glass composition or a glass composition, and an inorganic pigment is laminated | stacked on the cooking surface of the said board | substrate partially or the whole surface.
In this case, the effect of preventing the cooking surface from being damaged by wear of the heated object such as a pan and the cooking surface of the glass top plate for a heating cooker, or obtaining the effect of making the heated object difficult to slip. Can do.
Moreover, diversity can be imparted to the design.

Moreover, it is preferable that the ratio which occupies for the said painting glass decoration layer to the said cooking surface is 80% or less. In this case, the wear strength can be maintained without impairing the design. When the area occupied by the decorative glass decorative layer exceeds 80%, the exposed portion of the cooking surface of the glass top plate for a cooker becomes small, which may reduce the design.
The occupied area of the decorative glass decorative layer is more preferably 50% or less.

Moreover, it is preferable that the said decorating glass decoration layer is 1-15 micrometers in thickness. When the film thickness of the decorative glass decorative layer is less than 1 μm, the above-described effects may not be sufficiently obtained. On the other hand, when the film thickness of the said decorative glass decoration layer exceeds 15 micrometers, there exists a possibility that the said decorative glass decoration layer may peel.
The film thickness of the decorative glass decorative layer is more preferably 2 to 10 μm.

The glass composition is preferably a lead-free glass composition in consideration of recyclability and the like.
Moreover, it is preferable that the said glass composition is 650 degrees C or less in a softening point. The glass composition contains SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , Li ₂ O, and K ₂ O as essential components, and Na ₂ O, CaO, SrO, BaO, as necessary. It is more preferable to use a lead-free glass composition that contains one or more of ZnO, TiO ₂ , and ZrO ₂ as an additive component and is welded by heat treatment at 750 to 900 ° C.
The inorganic pigment described above can be used as the inorganic pigment.

Moreover, it is preferable that the said decoration glass decoration layer is formed so that it may become an arbitrary pattern.
In this case, the wear strength can be maintained without impairing the design.
Examples of the arbitrary pattern include a dot shape, a line shape, and a stone shape having a certain area.

Example 1
In this example, a glass top plate for a cooking device according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 is a cross-sectional view showing a glass top plate for a heating cooker of this example, and FIG. 2 is a view seen from the back side of the glass top plate for a heating cooker.

As shown in FIG.1 and FIG.2, the glass top plate 1 for heating cookers of this example is the glass top plate 1 arrange | positioned at the upper part of a heating cooker, Comprising: The board | substrate 2 which consists of translucent low expansion glass ceramics And the pearl tone layer 3 formed on the back side surface 22 which is the surface of the substrate 2 opposite to the cooking surface 21, and the coating layer 4 formed on the pearl tone layer 3.
Constructed by disposing a protective layer 61 made of a resin containing an inorganic pigment on the covering layer 4 and a transparent resin layer 51 made of a transparent resin on the covering layer 4. The translucent part 5 is provided.
The light transmitting portion 5 is configured to transmit light from the light source 81 disposed below the glass top plate 1, and the light blocking portion 6 is configured to block light from the light source 81.
This will be described in detail below.

  In producing the glass top plate 1 for a heating cooker, first, as the substrate 2, a light-transmitting low expansion crystallized glass ceramic (Neoceram N-0) having a β-quartz solid solution as a main crystal was prepared.

  Further, as a pearly layer forming material for forming the pearly layer 3, a pearl composed of 20% by mass of a commercially available white pearly material (particle size: 4 to 50 μm), 15% by mass of a silicone resin and 65% by mass of an acrylic resin. Toning tools were prepared.

  In addition, as a coating layer forming material for forming the coating layer 4, a diluted solution of an organometallic oxide composed of Au, Ti, and Bi was prepared. When only the coating layer 4 was formed on the substrate 2 using this coating layer forming material, the visible light transmittance was 25%.

Moreover, the material which consists of 70 mass% of silicone varnishes and 30 mass% of black inorganic pigments as a protective layer forming material which forms the said protective layer 61 was prepared.
Moreover, a silicone varnish was prepared as a transparent resin layer forming material constituting the transparent resin layer 51.

  Further, as a carbon electrode layer forming material for forming a carbon electrode layer 71 described later, a conductive carbon paste made of a conductive material and a vehicle was prepared. The conductive carbon paste contains 15 to 25 parts by weight of spherical graphite powder, 15 to 25 parts by weight of scaly graphite powder, and 10 to 20 parts by weight of acetylene black as the conductive material, and polyester as the vehicle. Contains 40 to 55 parts by weight of silicone resin. The average particle size of the graphite powder is 15 μm.

The conductive carbon paste is specifically prepared as follows.
First, spherical graphite powder, scaly graphite powder, and acetylene black were prepared as conductive materials. As the spherical graphite powder and the scaly graphite powder, those having an average particle diameter of 15 μm were used. In addition, a polyester silicone resin was prepared as a vehicle. In this example, “KR-5230” manufactured by Shin-Etsu Chemical Co., Ltd. was used as the polyester silicone resin.
Subsequently, the conductive carbon paste is mixed by mixing the above-mentioned spherical graphite powder: 19 parts by weight, scaly graphite powder: 19 parts by weight, acetylene black: 15.5 parts by weight, and polyester silicone resin: 46.5 parts by weight. Produced.

Then, two layers of the pearl tone layer forming material were printed on the back side surface 22 of the substrate 2 with a stainless steel 250 mesh. Thereafter, it was fired at 850 ° C. to form a pearl tone layer 3 composed of two layers. The pearl tone layer 3 had a thickness of 18 μm. Further, the visible light transmittance (light transmittance in the wavelength region of 380 to 780 nm) of the pearl tone layer 3 was 25%. The film thickness of the pearl tone layer 3 was measured using SEM (scanning electron microscope).
Thereafter, the coating layer forming material was printed on the pearl tone layer 3 with stainless steel 250 mesh. Thereafter, the coating layer 4 was formed by firing again at 850 ° C.

Next, the protective layer forming material was printed on the coating layer 4 with a stainless steel 250 mesh on the portion to be the light shielding portion 6.
In addition, the silicone varnish was printed with a Tetron 250 mesh on the coating layer 4 on the portion to be the light transmitting portion 5.

And the said carbon electrode layer forming material was printed with the stainless steel 250 mesh on required parts (electrode part 7), such as a site | part equivalent to the switch of the top surface operation of the back side surface 22. FIG.
Thereafter, curing is performed at 250 ° C. to form a protective layer 61 constituting the light shielding part 6, a carbon electrode layer 71 (electrode, wiring circuit, etc.) constituting the electrode part 7, and a transparent resin layer 51 constituting the light transmitting part 5, A glass top plate 1 for a heating cooker for a top surface operation type heating cooker was obtained.
At this time, a part of the transparent resin layer 51 and a part of the carbon electrode layer 71 may overlap each other.

  The glass top plate 1 for a heating cooker obtained in this example exhibited a silver tone with a strong whiteness.

  The glass top plate 1 for a heating cooker of this example can impart a pearly color tone to the glass top plate 1 for a heating cooker by providing a pearl tone layer 3 on the back side surface of the substrate 2.

  A covering layer 4 is laminated on the pearl tone layer 3. The covering layer 4 can suppress the dark color transmission of the protective layer 61 while ensuring translucency without impairing the texture of the pearl tone layer. The covering layer 4 also has a role of protecting the pearl tone layer 3.

  Further, the light shielding part 6 is configured by disposing a protective layer 61 made of a resin containing an inorganic pigment on the coating layer 4. Thereby, it is possible to prevent light from the light source 81 from being scattered in a portion other than the light transmitting portion 5. Moreover, it has the effect that the said structure is concealed also at the time of light emission of the light source 81 by forming in the part etc. in which the structure inside a cooking appliance is arrange | positioned below, and providing light-shielding property. Moreover, in the high-function addition electromagnetic cooker, there are some in which an internal part approaches the glass top plate 1 and there is only a narrow gap. In such a case, for example, there is a possibility that a wear mark may be generated in the pearl tone three layer or the coating layer 4 laminated on the back side surface of the substrate 2 due to vibration during transportation. And the said protective layer 61 also has the protective effect which suppresses the damage of the back side surface of the said glass top plate 1 for heating cookers.

  And the said translucent part 5 is comprised by arrange | positioning the transparent resin layer 51 which consists of transparent resin on the said coating layer 4. FIG. By forming the transparent resin layer 51 on the coating layer 4, wettability can be imparted to the translucent part 5 without reducing the translucency or improving the translucency. By imparting wettability to the light-transmitting part 5 as well as the light-shielding part 6, the color difference from the protective layer 61 forming part (light-shielding part 6) can be reduced. That is, when the light source 81 is not emitting light, the color difference between the translucent part 5 and the light-shielding part 6 is small, and it is difficult to identify the translucent part 5 from the cooking surface 21. it can. On the other hand, when the light source 81 emits light, only the light transmitting part 5 transmits light and emerges, so that the light transmitting part 5 can be clearly seen.

  In addition, since the pearl tone layer 3 itself has a certain degree of light-shielding property, even if the coating layer 4 and the protective layer 61 may be affected by some color, the pearl tone effect texture is improved. There is no inhibition. Therefore, the glass top plate 1 for a heating cooker can realize a pearly color with relatively high brightness due to the pearly effect of the pearly layer 3.

  Moreover, it has the electrode part 7 comprised by arrange | positioning the carbon electrode layer 71 on the said coating layer 4. As shown in FIG. Thereby, it can be made possible to deal with a glass touch type top surface operation type electromagnetic cooker that enables main operations on the cooking surface of the electromagnetic cooker.

  Further, since the light transmitting part 5 is provided in the vicinity of the electrode part 7 (switch part), the light transmitting part 5 in the vicinity of the carbon electrode layer 71 protrudes so that the electrode part 7 can be identified when the light source 81 emits light. It will be. Therefore, when the light source 81 is not emitting light, the electrode part 7 is not identified from the cooking surface, and the electrode part 7 appears only at the time of light emission so that the switch portion can be clearly seen. Can have.

(Example 2)
In this example, as shown in FIG. 3, the glass top plate for a heating cooker in which the pearl tone layer 3 in the glass top plate 1 for a heating cooker manufactured in Example 1 is changed to a pearl tone layer 302 composed of one layer. In this example, 102 is manufactured.

  Specifically, a pearl tone layer forming material similar to that of the pearl tone paint of Example 1 was printed on the back side surface 22 of the substrate 2 similar to the substrate of Example 1 with a stainless steel 250 mesh. Thereafter, it was baked at 850 ° C. to form a pearl tone layer 302 composed of one layer. The pearl tone layer 302 had a thickness of 12 μm. The visible light transmittance was 30%.

Other steps were carried out in the same manner as in Example 1 above, and a glass top plate 102 for a heating cooker was produced.
The glass top plate 102 for a heating cooker obtained in this example exhibited a white-colored silver tone.

(Example 3)
In this example, as shown in FIG. 4, a decorative glass decoration layer 82 is formed on the cooking surface 21 of the substrate 2 of the glass top plate 1 for a heating cooker produced in the above-described Example 1.
In producing the glass top plate 103 for a heating cooker of this example, first, as a decorative layer forming material for forming the decorative glass decorative layer 82, glass flux 80% by mass, organic binder 100% by mass, inorganic A paste material to be mixed with 20% by mass of pigment was prepared.

Here, as the glass flux, a SiO ₂ 65 wt%, the Al ₂ O ₃ 5 wt%, B ₂ O ₃ of 23 wt%, 1 wt% of Li ₂ O, and Na ₂ O 2 wt% , ₂ % by mass of K ₂ O, 1% by mass of TiO ₂ and 1% by mass of ZrO ₂ were used. Further, acrylic resin was used as the organic binder, and titanium oxide powder was used as the inorganic pigment.

Then, the paste material for the decoration layer is made of stainless steel 350 mesh, φ0.8 mm, pitch 3... On the heater portion where the cooking device of the cooking surface 21 of the substrate 2 similar to the substrate 2 of Example 1 is installed. Printing was performed in the form of dots aligned at 5 mm. Thereafter, the glass decorative layer 82 was formed by baking at 850 ° C. The painted glass decorative layer 82 had a thickness of 6 μm. The thickness of the decorative glass decorative layer 82 was measured by the same method as the pearl tone layer.
Thereafter, in the same manner as in Example 1, the pearl tone layer 3, the coating layer 4, the protective layer 61, the transparent resin layer 51, and the carbon electrode layer 71 are formed on the back side surface 22 of the substrate 2, and cooking is performed. A glass top plate 103 was obtained.
The glass top plate 103 for a heating cooker obtained in the present example exhibited a silver color with a strong whiteness as in Example 1.

Example 4
In this example, as shown in FIG. 5, the glass top plate for a heating cooker in which the pearl tone layer 3 in the glass top plate 103 for a heating cooker manufactured in Example 3 is changed to a pearl tone layer 302 composed of one layer. 104 is an example of manufacturing 104. That is, this is an example in which the same decorative glass decoration layer 82 as in Example 3 is formed on the cooking surface 21 of the substrate 2 of the glass top plate 1 for a heating cooker manufactured in Example 2.

In producing the glass top plate 104 for a heating cooker of the present example, the pearl tone layer 302 was formed in the same manner as in the above Example 2 except that the pearl tone layer 302 was formed in the same manner as in the above Example 3. It carried out by the method similar to Example 3, and produced the glass top plate 104 for heating cookers.
The glass top plate 104 for a heating cooker obtained in the present example exhibited a white tinted silver color as in Example 2.

(Example 5)
This example is an example in which the pearl tone layer forming material in Example 1 was changed to produce a glass top plate for a heating cooker.
Specifically, in this example, a pearl tone paint having a visible light transmittance of 28% when only the pearl tone layer is formed on the substrate using the pearl tone layer forming material was used. Specifically, the pearl color paint is composed of 12% by mass of a commercially available white pearl color material (particle size 4 to 50 μm), 15% by mass of silicone resin, and 73% by mass of acrylic resin.

Other steps were performed in the same manner as in Example 1.
The glass top plate for a heating cooker obtained in this example exhibited a silver-blue color tone with a slight bluish tinge.

(Example 6)
This example is an example in which the coating layer forming material in Example 1 was changed to produce a glass top plate for a cooking device.
Specifically, in this example, as a coating layer forming material, an organometallic oxide composed of Au, Ti, Bi, or the like having a visible light transmittance of 15% when only the coating layer is formed on the substrate using the coating layer forming material. A diluted solution of was used.

Other steps were carried out in the same manner as in Example 1 to produce a glass top plate for a heating cooker.
The glass top plate for a heating cooker obtained in this example exhibited a gray silver color with a slight bluish tint.

(Comparative Example 1)
In this example, a glass top plate for a heating cooker as a comparative example of the present invention will be described.
As shown in FIG. 6, the glass top plate 901 for the heating cooker of this example has a configuration in which the transparent resin layer 51 is not disposed in the light transmitting portion 5 in the glass top plate 1 for the heating cooker of the first embodiment. is there.

In this example, a glass top plate 901 for a heating cooker was produced by performing the same method as in Example 1 except that the transparent resin layer 51 was not disposed.
The glass top plate 901 for a heating cooker obtained in this example exhibited a silver color with a strong whiteness.

(Comparative Example 2)
In this example, as shown in FIG. 7, a glass top plate 902 for a heating cooker having a configuration in which the protective layer 61 in the glass top plate 1 for the heating cooker of Example 1 was not formed.

In this example, a glass top plate 902 for a heating cooker was produced by performing the same method as in Example 1 except that no protective layer was disposed.
The glass top plate 902 for a heating cooker obtained in this example exhibited a color tone of silver with a strong whiteness.

(Comparative Example 3)
In this example, as shown in FIG. 8, the glass top plate 903 for heating cookers which has the structure which has not formed the pearl tone layer 3 in the glass top plate 1 for heating cookers of the said Example 1 was produced.

In this example, a glass top plate 903 for a heating cooker was produced by performing the same method as in Example 1 except that no pearl tone layer was disposed.
The glass top plate 903 for a heating cooker obtained in this example exhibited a blue color tone not exhibiting a pearl tone.

(Comparative Example 4)
In this example, as shown in FIG. 9, a glass top plate 904 for a heating cooker having a configuration in which the coating layer 4 in the glass top plate 1 for the heating cooker of Example 1 was not formed was produced.

In this example, a glass top plate 904 for a cooking device was manufactured by performing the same method as in Example 1 except that no coating layer was disposed.
The glass top plate 904 for a heating cooker obtained in this example exhibited a slightly blackish gray silver color tone.

(Comparative Example 5)
In this example, as shown in FIG. 10, a raster layer 91 formed on the back side surface 22 of the substrate 2 and a carbon electrode layer 71 formed so as to have the light transmitting portion 6 on the raster layer 91 are provided. A glass top plate 905 for a cooker having was prepared.
In producing the glass top plate 905 for the heating cooker of this example, first, a black raster paste L-900 (trade name) is used by using stainless steel 250 mesh on the back side surface 22 of the substrate 2 as in Example 1 above. ) Was applied. Thereafter, firing was performed at 850 ° C. to form a raster layer 91. The raster layer 91 had a thickness of 2 μm.
Then, the electrode part 7 was formed on the said raster layer 91 by the method similar to the said Example 1, and the glass top plate 905 for heating cookers was obtained.
The glass top plate 905 for a heating cooker obtained in this example exhibited a black color that is the color of the raster layer 91.

(Comparative Example 6)
In this example, as shown in FIG. 11, a pearl tone layer 3 is formed between the substrate 2 and the raster layer 91 in the glass top plate 905 for a cooker obtained in Comparative Example 5 above.
In producing the glass top plate 906 for the heating cooker of this example, first, the pearl tone layer 3 was formed on the back side surface 22 of the substrate 2 similar to that of Example 1 by the same method as in Example 1 above. . Thereafter, a raster layer 91 and a carbon electrode layer 71 were formed on the pearl tone layer 3 in the same manner as in Comparative Example 7, thereby producing a glass top plate 906 for a heating cooker.
The glass top plate 906 for a heating cooker obtained in this example exhibited a pearly silver gray in which the color of the raster layer 91 affected the pearly effect of the pearly layer 3.

(Experimental example 1)
About the glass top plate for heating cookers obtained in Examples 1 to 6 and Comparative Examples 1 to 6, measurement of lightness on the cooking surface of the glass top plate for heating cookers at a wavelength of 380 nm to 780 nm The transmissivity of the translucent part of the glass top plate for a heating cooker, the color difference ΔE between the translucent part and the light-shielding part, and the concealability of the internal components of the electromagnetic cooker were evaluated.

<Lightness>
The brightness on the cooking surface of the glass top plate for a heating cooker is a spectral colorimetry made by X-Rite Co., Ltd. for the glass top plate for a heating cooker obtained in Examples 1 to 6, Comparative Examples 1 and 2, and Comparative Examples 5 and 6. Lightness (L value) was measured using a total X-rite SP60. The results are shown in Table 1.
Table 1 also shows the appearance color of the glass top plate for a heating cooker.

<Transmissivity>
The transmittance of the translucent part is measured by JASCO V manufactured by JASCO Corporation for the translucent part of the glass top plate for a heating cooker obtained in Examples 1 to 6, Comparative Examples 1 and 2, and Comparative Examples 5 and 6. The transmittance was measured using -570. The results are shown in Table 1.

<Color difference>
The color difference ΔE between the light transmitting part and the light shielding part (protective layer forming part) is the glass top plate for a heating cooker obtained in Examples 1 to 6, Comparative Examples 1 to 3, and Comparative Examples 5 and 6. Measurement was performed using a spectrocolorimeter X-rite sp60 manufactured by X-Rite. L, a, and b values were measured at each site and calculated by ΔE = {(ΔL) ² + (Δa) ² + (Δb) ² } ^1/2 .
In addition, about the glass top plate for heating cookers in which the said light-shielding part is not formed (Comparative Example 2, Comparative Example 5, and Comparative Example 6), Comparative Example 2 is a part where nothing is laminated on the coating layer. The color difference between the electrode part or the light transmitting part was measured, and Comparative Example 5 and Comparative Example 6 measured the color difference between the light transmitting part and the electrode part.
The case where the color difference ΔE was 1.5 or less was evaluated as “Good”, and the case where the color difference ΔE exceeded 1.5 was evaluated as “Poor”.

<Concealment of internal components of electromagnetic cooker>
The concealability of the internal components of the electromagnetic cooker is the electromagnetic in which the glass top plate for the heating cooker is arranged with respect to the glass top plate for the heating cooker obtained in Examples 1 to 6, Comparative Examples 1 and 2, and Comparative Examples 4 to 6. In the cooking device, it was evaluated by visually judging whether or not the internal parts permeate from the upper part (cooking surface) of the plate. If the internal parts can be sufficiently concealed, the evaluation is ○, if the internal parts can be confirmed slightly transparently, the evaluation is △, and if the internal parts are clearly visible, the evaluation is ×. . A case where the evaluation was ○ was accepted, and a case where the evaluation was Δ or × was rejected.

  As can be seen from Table 1, since the glass top plate for a heating cooker obtained in Examples 1 to 6 has a transmissivity of 8% or more in the light-transmitting part, at the time of light emission of the light source, The switch portion can be clearly visually recognized by the light emission of the light source. It can also be seen that the internal parts can be sufficiently concealed and the color difference ΔE is 1.5 or less, so that the switch part can be made inconspicuous from the cooking surface when the light source is not emitting light. Furthermore, the L value showed high brightness of 70 or more, and exhibited a color tone reflecting the color of the pearl tone layer.

Further, as is known from Table 1, the glass top plate for a heating cooker obtained in Comparative Example 1 does not have a transparent resin layer disposed in the light-transmitting portion, so the color difference ΔE is large and the color difference is unacceptable. It was.
Moreover, since the glass top plate for heating cookers obtained in Comparative Example 2 does not have a protective layer, the concealing property of the internal components of the electromagnetic cooker is insufficient, and light diffuses to the periphery when the light source emits light. The design was inferior. Further, a color difference was generated between the portion where nothing was laminated on the coating layer and the light transmitting portion or the electrode portion, which was unacceptable.

Moreover, since the glass top plate for heating cookers obtained in Comparative Example 3 does not have a pearl layer, the concealability of the internal components of the electromagnetic cooker is insufficient and the pearl layer is not formed. Therefore, it did not have a pearl tone.
Moreover, since the glass top plate for heating cookers obtained in Comparative Example 4 does not have a coating layer, the dark color of the protective layer and the carbon electrode layer is slightly transmitted when the light source is not emitting light. The color difference ΔE between the light-shielding part and the light-shielding part was increased, and the color difference was not acceptable.

Moreover, since the glass top plate for heating cookers obtained in Comparative Example 5 is provided with a raster layer on the substrate, good results are obtained with respect to the transmissivity of the translucent part, the concealability of the cooker internal parts, and the color difference. However, since the brightness was less than 70% and no pearl tone layer was formed, it did not have a pearl tone.
Moreover, since the glass top plate for heating cookers obtained in Comparative Example 6 has a raster layer formed on the pearl tone layer, the transmissivity of the translucent part is low, and the switch part is clearly defined when the light source emits light. It was insufficient in the function of making it visually recognized.

  Moreover, with respect to the glass top plate for heating cookers obtained in the said Example 1- Example 6, it does an impact test and a thermal shock test, and does it have intensity | strength required as a glass top plate for heating cookers? Evaluated whether or not.

<Impact test>
The impact test was performed assuming that a pan or the like dropped on the plate when the glass top plate for a heating cooker was actually used.
About each glass top plate for cooking-by-heating machines, the board of the magnitude | size of 40 cm x 50 cm square was prepared, and 4 corners were supported and fixed by the 2 cm chip | tip.
And the test which drops 500g of hard balls with respect to the said plate was done. The drop height started from 50 mm and increased every 400 mm to 400 mm. If it passes 400 mm, the strength is practically acceptable.
The results are shown in Table 2. In Table 2, when it passed 400 mm, it displayed as (circle).

<Thermal shock test>
The thermal shock test was conducted assuming that when the glass top plate for a heating cooker is actually used, the plate may be heated to close to 600 ° C., so that water is spilled on the heated top plate. .
About each glass top plate for heating cookers, the plate cut out to 10 square cm was prepared.
And the test which heats the said plate with a furnace so that it may become 620 degreeC, and drops this in 20 degreeC water was repeated 5 times.
The results are shown in Table 3. In Table 3, it can be said that when there is no crack in the substrate (evaluation ◯) and when the pearly layer is not peeled off from the substrate (evaluation ◯), the substrate has a strength with no practical problem.

  As can be seen from Table 2 and Table 3, it can be seen that any of the glass top plates for a heating cooker obtained in Examples 1 to 6 has a strength that causes no problem in practice.

  As described above, according to this example, the structure inside the cooker can be sufficiently concealed even when the color tone is high in brightness, and when the light source is not lit, the translucent part is formed from the cooking surface. When the light source emits light, it can be seen that a glass top plate for a heating cooker can be provided in which the light-transmitting portion can be clearly visually recognized by the light emission of the light source.

Sectional drawing which shows the glass top plate for heating cookers in Example 1. FIG. Explanatory drawing which shows the glass top plate for heating cookers in Example 1. FIG. Sectional drawing which shows the glass top plate for heating cookers in Example 2. FIG. Sectional drawing which shows the glass top plate for heating cookers in Example 3. FIG. Sectional drawing which shows the glass top plate for heating cookers in Example 4. FIG. Sectional drawing which shows the glass top plate for heating cookers in the comparative example 1. FIG. Sectional drawing which shows the glass top plate for heating cookers in the comparative example 2. FIG. Sectional drawing which shows the glass top plate for heating cookers in the comparative example 3. FIG. Sectional drawing which shows the glass top plate for heating cookers in the comparative example 4. FIG. Sectional drawing which shows the glass top plate for heating cookers in the comparative example 5. FIG. Sectional drawing which shows the glass top plate for heating cookers in the comparative example 6. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass top plate for heating cookers 2 Board | substrate 21 Cooking surface 22 Back side surface 3 Pearl tone layer 4 Coating layer 5 Light transmission part 51 Transparent resin layer 6 Light-shielding part 61 Protection layer 81 Light source

Claims (6)

In the glass top plate placed at the top of the heating cooker,
A substrate made of translucent low-expansion glass ceramics, a pearly layer formed on the back side opposite to the cooking surface of the substrate, and a coating layer formed on the pearly layer Have
A light shielding part constituted by disposing a protective layer made of a resin containing an inorganic pigment on the coating layer;
A translucent part constituted by disposing a transparent resin layer made of a transparent resin on the coating layer;
The visible light transmittance of the translucent part is 3.5% or more,
In the translucent part, it is configured to transmit light from a light source disposed below the glass top plate, and to shield light from the light source in the light shielding part ,
Having an electrode part configured by disposing a carbon electrode layer on the coating layer;
The electrode part is a switch part for the top operation of the glass top plate,
The translucent part is for displaying the switch part,
The glass top plate for a heating cooker , wherein a color difference ΔE between the light transmitting portion and the light shielding portion on the cooking surface of the substrate when the light source is not emitting light is 1.5 or less . In Claim 1, the lightness (L value) in the said cooking surface is 70 or more, The glass top plate for heating cookers characterized by the above-mentioned. 3. The pearl tone layer according to claim 1 , wherein the content of the pearl tone material is more than 10% by mass and 30% by mass or less, the silicone resin or siliceous sol is 10% by mass to 30% by mass, and the organic binder is A glass top plate for a heating cooker, characterized in that a pearl-colored paint of 40% by mass or more and less than 80% by mass is baked with a picture on the substrate. The glass top plate for a heating cooker according to any one of claims 1 to 3, wherein the coating layer is formed by applying a dilute solution of an organometallic compound onto the pearl tone layer and baking it. 5. The glass top plate for a heating cooker according to claim 1, wherein the protective layer is formed by applying and baking a heat-resistant resin and an inorganic pigment. The glass top plate for a heating cooker according to any one of claims 1 to 5, wherein the carbon electrode layer is formed by applying a conductive carbon paste and baking.

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