JP2008016318A - Glass top plate for electromagnetic cooker, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass top plate for an electromagnetic cooker capable of showing a mat without having luster without losing original strength of substrate glass. <P>SOLUTION: This glass top plate is composed by stacking one or more layers of mat decorating glass 3 formed of a glass composition on the back surface 22 of the substrate glass 2 formed of transparent low-expansion glass, and stacking one or more layers of glossy layers or shading layers 4. The linear thermal expansion coefficient of the substrate glass 2 is -10 to 30×10<SP>-7</SP>/°C (30-500°C), and that of the mat decorating glass 3 is -10 to 30×10<SP>-7</SP>/°C (30-500°C). The glass composition contains at least one kind of low-expansion crystal such as β-quartz, β-spodumene, aluminum titanate or cordierite. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a glass top plate for a cooker disposed on the top of the cooker and a method for manufacturing the same.

  Conventionally, a top plate for a cooker made of a glass plate is installed on the top of a cooker such as an electromagnetic cooker or a gas cooker. An object to be heated such as a pan is installed on the top plate for the cooker, and the object to be heated can be cooked by a heating device inside the cooker. In particular, electromagnetic cookers tend to be increasingly demanded in recent years because of their high safety, and accordingly, the demand for top plates for cookers is also increasing.

As such a top plate for a cooker, techniques (Patent Documents 1 and 2) for decorating colors on a substrate glass have been reported in order to enhance the design.
In view of the concealability of the internal structure, the technique described in Patent Document 1 can only express a change in color tone of a raster color. Further, in order to change the color tone with the raster color, it is necessary to laminate the raster paint, which may impair the original strength of the translucent glass plate. Moreover, the expression of matte (matte) or glossy (bright) was difficult due to the nature of the raster.

The technique described in Patent Document 2 is for painting a pearl-colored paint composed of a pearl-colored material and a silicone resin or a siliceous sol on a translucent low-expansion glass ceramic. However, the expression with the pearl tone paint and the light shielding layer can express the bright, but cannot express the mat.
Therefore, establishment of a decoration technique capable of expressing a matte matte has been desired.

JP-A-3-065532 JP 2001-213642 A

  The present invention has been made in view of such conventional problems, and intends to provide a glass top plate for an electromagnetic cooker capable of expressing a matte mat without losing the original strength of the substrate glass. It is.

In the first invention, one or more layers of a mat decorative glass made of a glass composition are laminated on the back surface of a substrate glass made of transparent low expansion glass, and further, a glossy layer or a light shielding layer is laminated in one or more layers. And
The substrate glass has a linear thermal expansion coefficient of −10 to 30 × 10 ⁻⁷ / ° C. (30 to 500 ° C.),
The glass for mat decoration has a linear thermal expansion coefficient of −10 to 30 × 10 ⁻⁷ / ° C. (30 to 500 ° C.).

  As described above, the glass top plate for an electromagnetic cooker is formed by laminating one or more layers of the mat decorative glass on the back surface of the substrate glass, and further laminating one or more layers of a glossy layer or a light shielding layer. It is. That is, the presence of the mat decoration glass between the substrate glass and the glossy layer or the light shielding layer allows the glass top plate for the electromagnetic cooker to express a matte matte. .

The substrate glass has a linear thermal expansion coefficient of −10 to 30 × 10 ⁻⁷ / ° C. (30 to 500 ° C.), and the mat decorative glass has a linear thermal expansion coefficient of −10 to 30 × 10 ^{− 7} / ° C (30-500 ° C).
Thus, since the difference in the coefficient of linear thermal expansion between the substrate glass and the mat decoration glass is small, it is possible to reduce the occurrence of cracks due to the difference in thermal expansion between the substrate glass and the mat decoration glass, The original strength of the substrate glass is not lost. Therefore, the glass top plate for an electromagnetic cooker of the present invention was able to obtain an excellent effect that a matte mat can be expressed without losing the original strength of the substrate glass.

The second invention is for an electromagnetic cooker by laminating one or more layers of a mat decorative glass on the back surface of a substrate glass made of transparent low expansion glass, and further laminating one or more layers of a glossy layer or a light shielding layer. A method for producing a glass top plate, comprising:
A paste in which an organic resin is added to a glass composition containing at least one low expansion crystal such as β-quartz, β-spodumene, aluminum titanate, cordierite, etc. is applied to the back surface of the substrate glass,
By performing a heat treatment in the range of 700 to 900 ° C., a mat decorative glass is formed,
Thereafter, the paste for forming the glossy layer or the light shielding layer is further applied to the back surface of the substrate glass and heat-treated to form the glossy layer or the light shielding layer. It exists in a manufacturing method (Claim 11).

  In the method for producing a glass top plate for an electromagnetic cooker according to the present invention, as described above, at least one kind of low expansion crystal such as β-quartz, β-spodumene, aluminum titanate, cordierite, or the like is formed on the back surface of the substrate glass. The paste for which the organic resin was added to the glass composition to contain is apply | coated, and the glass for mat | matte decorations is formed by heat-processing at 700-900 degreeC.

  And the paste for forming the said glossy layer or light-shielding layer is further apply | coated to the back surface of the said substrate glass, and it heat-processes, thereby laminating | stacking 1 layer or multiple layers of a glossy layer or light-shielding layer. Thereby, the glass top plate for electromagnetic cookers with a matte tone can be obtained without losing the original strength of the substrate glass.

In order to form the mat decoration layer into a paste containing a glass composition, for example, a coating method having excellent film forming properties such as a screen printing method can be performed.
Examples of the organic resin include acrylic resins, amide resins, alkyd resins, and cellulose resins.
Moreover, the said paste may contain the organic solvent as needed.

  The gloss layer or the light shielding layer can be formed by various known methods. The light shielding layer can be formed, for example, by applying a raster paste or a paste made of a glass composition and an inorganic pigment and performing a heat treatment. The gloss layer can be formed, for example, by applying a paste made of a pearl tone material and a glass composition, or a paste made of a pearl tone material and a silicone resin or siliceous sol and heat-treating it. .

As described above, the glass top plate for an electromagnetic cooker according to the first aspect of the present invention has a linear thermal expansion coefficient outside the range of −10 to 30 × 10 ⁻⁷ / ° C. (30 to 500 ° C.). There is a problem that it is not suitable as a substrate glass used for a glass top plate for cooking.
Moreover, when the said glass for mat | matte decorations remove | deviate from the range whose linear thermal expansion coefficient is -10-30 * 10 < ^-7 > / degreeC (30-500 degreeC), the difference with the linear thermal expansion coefficient of the said board | substrate glass is. There arises a problem that it is generated, which causes cracks and deteriorates the strength of the glass top plate for an electromagnetic cooker.

  The glass composition of the present invention preferably contains at least one low expansion crystal such as β-quartz, β-spodumene, aluminum titanate, cordierite, etc. (Claim 2).

  Since the glass composition contains at least one kind of low expansion crystal such as β-quartz, β-spodumene, aluminum titanate, cordierite, etc., the coefficient of thermal expansion becomes small as described above. Therefore, by adopting the glass composition as a glass for mat decoration, an excellent effect that the original strength of the substrate glass is not lost can be obtained.

Moreover, it is preferable that the said mat | matte decoration glass contains 80 wt% or less of inorganic pigments (Claim 3).
In this case, the mat decorative glass can be expressed in an arbitrary color without reducing the original strength of the substrate glass, and the design can be improved.
Further, when the inorganic pigment exceeds 80 wt%, the adhesion to the substrate glass may be deteriorated, and a part of the mat decorative glass is lost when the glossy layer and the light shielding layer are laminated. There is a fear.

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, as the white inorganic pigment, for _{example, TiO 2, ZrO 2, ZrSiO} 4, Al 2 O 3, 3Al 2 O 3 -2SiO 2, Li 2 O · Al 2 O 3 · 8SiO 2 or the like can be mentioned It is done.

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.

Further, the mat decorative glass is preferably laminated so as to form an arbitrary pattern.
In this case, the matte glass is laminated in the portion where the mat decorative glass is laminated, and the other portion can express the glossy bright. Therefore, the design is excellent. .
Examples of the pattern include a dot shape, a line shape, a solid with a certain area, etc., and it is possible to adopt a technique such as gradation expression.

Moreover, it is preferable that the said glossy layer consists of a pearl tone paint which consists of a pearl tone material and a glass composition.
In this case, the designability can be improved without reducing the original strength of the substrate glass.

Moreover, as said pearl tone material, it is preferable to use what coated the inorganic pigment with titanium oxide, zirconium oxide, iron oxide etc., for example.
Further, the gloss layer may contain an inorganic pigment as an outer coating of 20 wt% or less when the total content of the pearly material and glass is 100 wt%.

  Moreover, as the glass composition for the gloss layer, it is preferable to employ the same glass composition as that used for the mat decorative glass.

The glossy layer is preferably composed of a pearl color material made of a pearl color material and a silicone resin or siliceous sol.
In this case, the designability can be improved without reducing the original strength of the substrate glass.
Examples of the pearl tone material include the pearl tone materials described above.

The silicone resin is a polymer of an organosilicon compound having a siloxane bond as a main skeleton.
Moreover, as a siliceous sol, the silica sol obtained by hydrolyzing ethylsilicate etc., colloidal silica sol, etc. can be used, for example.

  Further, the gloss layer may contain an inorganic pigment in a range of 20 wt% or less when the total content of the pearl tone material and the silicone resin or siliceous sol is 100 wt%.

Moreover, it is preferable that the said light shielding layer consists of a raster color.
Examples of the raster colors include organic materials such as Au, Pt, Pd, Rh, Ru, Bi, Sn, Ni, Fe, Cr, Ti, Ca, Si, Ba, Sr, Mg, Ag, Zr, In, and Mn. A diluted solution of a metal compound can be mentioned. A plurality of these organometallic compound diluted solutions can be mixed at an arbitrary ratio.

Moreover, it is preferable that the said light shielding layer consists of an inorganic pigment and a glass composition (Claim 8).
In this case, the design can be improved without reducing the original strength of the substrate glass.

The inorganic pigment described above can be used as the inorganic pigment.
The glass composition for the light shielding layer is preferably the same as the glass composition used for the mat decorative glass.

The substrate glass is preferably a transparent low expansion crystallized glass plate having a main crystal of β-quartz solid solution or β-spodumene (Claim 9).
The transparent low expansion crystallized glass plate having the β-quartz solid solution or β-spodumene as a main crystal is particularly suitable as a substrate glass for a glass top plate for an electromagnetic cooker.

Moreover, it is preferable that the cooking surface decoration glass which consists of a glass composition is formed in the cooking surface side part or whole surface of the glass top plate for electromagnetic cookers (Claim 10).
In this case, it is possible to obtain an effect that the design property can be improved without reducing the original strength of the substrate glass.

Moreover, it is preferable to use the same glass composition as the glass composition used for the glass for mat decoration, as the glass composition for cooking surface decoration glass. More specific composition is preferably adjusted so that the linear thermal expansion coefficient becomes −10 to 50 × 10 ⁻⁷ / ° C. (30 to 500 ° C.).
Moreover, the said decoration layer may contain 30 wt% or less of inorganic pigments.

Moreover, the glass top plate for electromagnetic cookers of this invention may adhere | attach a temperature sensor on the surface of the said glossy layer or light shielding layer using an adhesive agent. In this case, a glass layer or a heat resistant resin may be further formed at the place where the adhesive is applied.
The glass layer may contain 10 wt% or less of an inorganic pigment, and the heat resistant resin may contain 50 wt% or less of an inorganic pigment.

Moreover, it is preferable that the said glass layer consists of a thing similar to the glass composition used for the said mat | matte decoration glass. A more specific composition of the glass composition includes at least one low expansion crystal such as β-quartz, β-spodumene, aluminum titanate, cordierite, etc., and a linear thermal expansion coefficient of −10 to 30. It is preferable to adjust so that it may become x10 < ^-7 > / degreeC (30-500 degreeC).
Moreover, as said heat resistant resin, a silicone resin, a phenol resin, a polyimide resin etc. are mentioned, for example.

Moreover, it is preferable that the conductive layer is formed in at least one of the surface or the back surface of the glass top plate for electromagnetic cookers.
In this case, the main operation can be performed on the cooking surface of the glass top plate for an electromagnetic cooker.

  The conductive layer is made of, for example, carbon paste, lead-free solder, raster paste containing at least one of Au, Pt, Pd, noble metal powder such as Ag, Au, Pt, Pd, and glass flux powder made of acrylic resin, amide Resin, alkyd resin, paste kneaded with cellulose resin, paste kneaded noble metal powder such as Ag, Au, Pt, Pd with resin such as silicon resin, phenol resin, polyimide, Zn-Sn metal paste, In-Sn metal paste or the like can be applied by screen printing or the like and baked.

Also, do not form a light-shielding layer or a glossy layer on a part of the glass top plate for an electromagnetic cooker or display the thickness of the light-shielding layer or the glossy layer so that precautions (handling instructions) are displayed from the cooking surface side. The thickness may be reduced, or a transparent heat-resistant resin or glass layer may be formed instead of the light shielding layer and the glossy layer.
In this case, it can be clearly recognized from the indicator cooking surface that displays the amount of applied electric power. In addition, the light shielding property may be adjusted in accordance with the function.

  In the method for producing a glass top plate for an electromagnetic cooker according to the second invention, as described above, at least one low expansion crystal such as β-quartz, β-spodumene, aluminum titanate, cordierite or the like is formed on the back surface of the substrate glass. The glass for mat | matte decoration is formed by apply | coating the glass composition containing seed | species or more, and performing heat processing in the range of 700-900 degreeC.

  When heat treatment is performed at a temperature lower than 700 ° C., the glass composition is not easily melted and the mat decorative glass may be lost. On the other hand, when the heat treatment is performed at a temperature higher than 900 ° C., the substrate glass is There is a problem of cloudiness.

The glass composition is preferably a low expansion glass having a linear thermal expansion coefficient of −10 to 30 × 10 ⁻⁷ / ° C. (30 to 500 ° C.).

  In this case, the linear thermal expansion coefficient difference between the substrate glass and the mat decorative glass is reduced. Therefore, even if it is a precise | minute film | membrane, the glass top plate for electromagnetic cookers which can suppress intensity deterioration with respect to the load from the surface can be manufactured.

(Example 1)
This example demonstrates the Example concerning the glass top plate for electromagnetic cookers of this invention using FIG.
In this example, one or more layers of a mat decoration glass 3 made of a glass composition are laminated on the back surface 22 of a substrate glass 2 made of transparent low expansion glass, and further, one light shielding layer 4 is laminated.
The substrate glass 2 has a linear thermal expansion coefficient of −10 to 30 × 10 ⁻⁷ / ° C. (30 to 500 ° C.), and the mat decorative glass 3 includes β-quartz, β-spodumene, aluminum titanate, It contains at least one low expansion crystal such as cordierite and has a linear thermal expansion coefficient of −10 to 30 × 10 ⁻⁷ / ° C. (30 to 500 ° C.).
This will be described in detail below.

The manufacturing method of the glass top plate 1 for electromagnetic cookers of this example is demonstrated. First, SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , and Li ₂ O are SiO ₂ : 56.5 wt%, Al ₂ O ₃ : 21.5 wt%, B ₂ O ₃ : 13 wt%, Li ₂ O: 9 wt. A glass composition containing a mixing ratio of% was prepared.

Here, the obtained glass composition contained β-spodumene and became a low expansion glass having a linear thermal expansion coefficient of 15 × 10 ⁻⁷ / ° C. (30 to 500 ° C.).

A glass paste was produced by kneading 100 parts by weight of the glass composition and 100 parts by weight of an organic resin. And the said glass paste is apply | coated to the whole back surface 22 of the board | substrate glass 2 by a screen-printing method using stainless steel # 400 mesh, it baked as heat processing at 850 degreeC, and a linear thermal expansion coefficient is 15 * 10 < ^-7 > /. The glass 3 for mat | matte decoration of 30 degreeC (30-500 degreeC) was formed.
As the organic resin, an acrylic resin is used. As the substrate glass 2, the main crystal is β-quartz solid solution, and the linear thermal expansion coefficient is −5 × 10 ⁻⁷ / ° C. (30 to 500 ° C.). The product name Neoceram N-0 was used.

Next, a black raster paste was applied to the surface of the mat decorative glass 3 using stainless steel # 250 mesh. This was baked again at 850 ° C. to form the light shielding layer 4. As the raster paste, a commercially available black raster paste was used.
Thereby, the glass top plate 1 for electromagnetic cookers of the black mat | matte with black gloss was able to be obtained.

(Example 2)
In this example, as shown in FIG. 2, the mat decorative glass 3 in Example 1 is laminated in an arbitrary pattern.
Others are the same as in the first embodiment.
The glass 102 for mat decoration of this example is applied to the back surface 22 of the substrate glass 2 by a screen printing method using a glass paste similar to that of Example 1 in an arbitrary pattern using a stainless steel # 400 mesh and baked at 850 ° C. By doing so, the glass for mat decoration 3 having a linear thermal expansion coefficient of 15 × 10 ⁻⁷ / ° C. (30 to 500 ° C.) was formed.

  As a result, a black mat was obtained on the mat decoration glass 3 and a glossy black bright glass top plate 102 for the electromagnetic cooker was obtained on the other portions.

(Example 3)
In this example, as shown in FIG. 3, the light shielding layer 4 in Example 2 is changed to a glossy layer 5. Others are the same as in the second embodiment.
Specifically, Engelhard's Magna Pearl # 3000 is used as the pearl tone material 51, 5 parts by weight of this pearl tone material, 15 parts by weight of glass powder, 76 parts by weight of an organic solvent, and 4 parts by weight of an organic resin. And paste-like pearl paint.
On the surface on which the mat decorative glass 3 was formed, the pearl color paint was applied by screen printing using stainless steel # 250 mesh, and baked as a heat treatment at 850 ° C. to form the gloss layer 5.

As the organic solvent, butyl cellosolve was used, and as the organic resin, thickening ethylcellulose was used.
As a result, a glass top plate 103 for an electromagnetic cooker having a pearl tone mat on the mat decoration glass 3 and a pearl tone bright on the other portions could be obtained.

Example 4
In this example, as shown in FIG. 4, a gloss layer 5 is formed between the substrate glass 2 and the light shielding layer 4 of Example 2.
Others are the same as in the second embodiment.

Specifically, Engelhard's Magna Pearl # 3000 is used as the pearl tone material 51, 5 parts by weight of this pearl tone material, 15 parts by weight of glass powder, 76 parts by weight of an organic solvent, and 4 parts by weight of an organic resin. And paste-like pearl paint.
On the surface on which the mat decorative glass 3 was formed, the pearl color paint was applied by screen printing using stainless steel # 250 mesh, and baked as a heat treatment at 850 ° C. to form the gloss layer 5.
As the organic solvent, butyl cellosolve was used, and as the organic resin, thickening ethylcellulose was used.

Next, a black raster paste was applied to the surface of the gloss layer 5 by screen printing using stainless steel # 250 mesh. This was baked again at 850 ° C. to form the light shielding layer 4. As the raster paste, a commercially available black raster paste was used.
As a result, a silver gray pearl tone mat on the mat decoration layer 3 and a silver gray pearl tone bright glass top plate 104 for the electromagnetic cooker were obtained on the other portions.

(Example 5)
In this example, as shown in FIG. 5, the light shielding layer 4 of Example 4 is changed to a light shielding layer 6. Others are the same as in Example 4.
The light shielding layer 6 in this example is composed of 20 parts by weight of a pearl material, 20 parts by weight of an inorganic pigment (including 18 parts by weight of a white inorganic pigment and 2 parts by weight of a black inorganic pigment), 60 parts by weight of a glass composition, and an organic resin. 100 parts by weight was kneaded to prepare a paste-like light shielding material. This light shielding material was applied to the surface of the glossy layer 5 by screen printing using stainless steel # 250 mesh. This was baked again at 850 ° C. to form the light shielding layer 6.

As the pearl material 51, Engelhard's Magna Pearl # 3000 is used, and as the inorganic pigment 61, TiO ₂ powder as a white inorganic pigment and Fe—Cr—Co-based oxide as a black inorganic material are used. An acrylic resin was used as the organic resin.
As a result, a silver gray pearl tone mat on the mat decoration layer 3 was obtained, and a silver gray pearl tone bright glass top plate 105 for the electromagnetic cooker was obtained at the other portions.

(Example 6)
This example is an example in which the gloss layer 5 in Example 4 is changed. Others are the same as in Example 4.
Specifically, Engelhard's Magna Pearl # 3000 is used as a pearl tone material, 5 parts by weight of this pearl tone material, 15 parts by weight of a silicone resin (containing 50 parts by weight of an organic solvent), and 76 parts by weight of an organic solvent. And 4 parts by weight of an organic resin were kneaded to prepare a paste-like pearl color paint.

  In the same manner as in Example 4, the pearl color paint was applied to the surface on which the mat decorative glass was formed by a screen printing method using stainless steel # 250 mesh, and baked as a heat treatment at 850 ° C. A gloss layer made of resin was formed.

As the organic solvent, butyl cellosolve was used, and as the organic resin, thickening ethylcellulose was used.
Thereby, a silver gray pearl tone mat was obtained on the mat decoration layer, and a silver gray pearl tone bright glass top plate for an electromagnetic cooker was obtained on the other portions.

(Example 7)
In this example, the gloss layer of Example 5 is changed. Others are the same as in the fifth embodiment.
Specifically, Engelhard's Magna Pearl # 3000 is used as a pearl tone material, 5 parts by weight of this pearl tone material, 15 parts by weight of a silicone resin (containing 50 parts by weight of an organic solvent), and 76 parts by weight of an organic solvent. And 4 parts by weight of an organic resin were kneaded to prepare a paste-like pearl color paint.

  In the same manner as in Example 5, the above pearl color paint was applied by screen printing using stainless steel # 250 mesh on the surface on which the mat decorative glass was formed, and baked as a heat treatment at 850 ° C. A gloss layer made of resin was formed.

As the organic solvent, butyl cellosolve was used, and as the organic resin, thickening ethylcellulose was used.
Thereby, a silver gray pearl tone mat was obtained on the mat decoration layer, and a silver gray pearl tone bright glass top plate for an electromagnetic cooker was obtained on the other portions.

(Comparative Example 1)
In this example, the mat decorative glass of Example 1 is changed.
Specifically, the mixing ratio is SiO ₂ : 65 wt%, Al ₂ O ₃ : 5 wt%, B ₂ O ₃ : 25 wt%, Li ₂ O: 1 wt%, Na ₂ O: 2 wt%, K ₂ O: 2 wt%. A glass composition was prepared.

The obtained glass composition had a linear thermal expansion coefficient of 40 × 10 ⁻⁷ / ° C. (30 to 500 ° C.).
Using this glass composition and the same substrate glass, organic resin, and raster paste as in Example 1, a glass top plate for an electromagnetic cooker was produced in the same manner as in Example 1.

<Evaluation>
In this example, an impact test was performed on the glass top plate for an electromagnetic cooker produced in Examples 1 to 7 and Comparative Example 1 to evaluate the strength.
The impact test was performed assuming that a pan or the like dropped on the glass top plate for an electromagnetic cooker.

  The test method was as follows. For the glass top plate for an electromagnetic cooker produced in Examples 1 to 7 and Comparative Example 1, a plate having a thickness of 4 mm and a size of 400 mm × 550 mm square (sample E1 to sample E7 and sample C1). ), And four corners were supported and fixed by 20 mm square tips.

Thereafter, 500 g of hard balls were dropped on the plate, the state of the substrate glass and the decorative glass was observed, and the strength was evaluated. The height of the drop starts from 50 mm and increases every 50 m up to 400 mm.
The evaluation results are shown in Table 1. ○ is passed and × is rejected.
Moreover, when it passes at 400 mm, it can be said that the strength has no practical problem.

(Evaluation criteria)
○: When no crack or crack occurs ×: When a crack or crack occurs

  As shown in Table 1, Sample E1 to Sample E7, which are examples of the present invention, showed good results in the impact test. From this, the glass top plate for electromagnetic cookers of matte tone was obtained without losing the original strength of the substrate glass.

  Moreover, as is known from Table 1, the sample C1 as a comparative example of the present invention has a coefficient of linear thermal expansion of the glass for mat decoration exceeding the upper limit of the present invention. Therefore, since the difference in thermal expansion between the substrate glass and the glass for back surface decoration becomes large, cracks and cracks occurred due to a drop from a height of 300 mm, which was unacceptable.

Explanatory drawing which shows the glass top plate for electromagnetic cookers in Example 1. FIG. Explanatory drawing which shows the glass top plate for electromagnetic cookers in Example 2. FIG. Explanatory drawing which shows the glass top plate for electromagnetic cookers in Example 3. FIG. Explanatory drawing which shows the glass top plate for electromagnetic cookers in Example 4. FIG. Explanatory drawing which shows the glass top plate for electromagnetic cookers in Example 5. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass top plate for electromagnetic cookers 2 Substrate glass 22 Back surface 3 Glass for mat decoration 4 Light shielding layer

Claims (12)

One or more layers of a mat decorative glass made of a glass composition are laminated on the back surface of a substrate glass made of transparent low expansion glass, and further, a glossy layer or a light shielding layer is laminated in one or more layers,
The substrate glass has a linear thermal expansion coefficient of −10 to 30 × 10 ⁻⁷ / ° C. (30 to 500 ° C.),
A glass top plate for an electromagnetic cooker, wherein the mat decorative glass has a linear thermal expansion coefficient of -10 to 30 x ^10-7 / ° C (30 to 500 ° C).   2. The glass top plate for an electromagnetic cooker according to claim 1, wherein the glass composition contains at least one kind of low expansion crystal such as β-quartz, β-spodumene, aluminum titanate, cordierite and the like.   3. The glass top plate for an electromagnetic cooker according to claim 1, wherein the mat decorative glass contains an inorganic pigment in an amount of 80 wt% or less.   The glass top plate for an electromagnetic cooker according to any one of claims 1 to 3, wherein the mat decorative glass is laminated so as to form an arbitrary pattern.   The glass top plate for an electromagnetic cooker according to any one of claims 1 to 4, wherein the glossy layer is made of a pearl color paint composed of a pearl color material and a glass composition.   The glass top plate for an electromagnetic cooker according to any one of claims 1 to 5, wherein the gloss layer is made of a pearl-colored paint made of a pearl-colored material and a silicone resin or a siliceous sol.   The glass top plate for an electromagnetic cooking device according to any one of claims 1 to 6, wherein the light shielding layer is made of a raster color.   The glass top plate for an electromagnetic cooker according to any one of claims 1 to 7, wherein the light shielding layer is composed of an inorganic pigment and a glass composition.   The glass top plate for an electromagnetic cooker according to any one of claims 1 to 8, wherein the substrate glass is a transparent low expansion crystallized glass plate having a β-quartz solid solution or β-spodumene as a main crystal. .   In any one of Claims 1-9, the glass for cooking surface decoration which consists of a glass composition is formed in the cooking surface side part or whole surface of the glass top plate for electromagnetic cookers, The electromagnetic cooking characterized by the above-mentioned. Glass top plate for dexterity. A glass top plate for an electromagnetic cooker is manufactured by laminating one or more layers of a mat decoration glass on the back surface of a substrate glass made of transparent low expansion glass, and further laminating one or more layers of a glossy layer or a light shielding layer. A method,
A paste in which an organic resin is added to a glass composition containing at least one low expansion crystal such as β-quartz, β-spodumene, aluminum titanate, cordierite, etc. is applied to the back surface of the substrate glass,
By performing a heat treatment in the range of 700 to 900 ° C., a mat decorative glass is formed,
Thereafter, the paste for forming the glossy layer or the light shielding layer is further applied to the back surface of the substrate glass and heat-treated to form the glossy layer or the light shielding layer. Production method. 12. The glass top plate for an electromagnetic cooker according to claim 11, wherein the glass composition is a low expansion glass having a linear thermal expansion coefficient of −10 to 30 × 10 ⁻⁷ / ° C. (30 to 500 ° C.). Manufacturing method.

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