JP2021060156A - Cooker top plate and method for manufacturing the same - Google Patents

Abstract

To provide a cooker top plate that is less likely to cause a mottle due to a vaporized adhesive agent when being viewed from a cooking surface side, and is excellent in external appearance property.SOLUTION: A cooker top plate 1 includes: a glass substrate 2 including a cooking surface 2a on which cooking equipment is placed and a rear surface 2b on an opposite side to the cooking surface 2a; and a heat resistant resin layer 4 disposed on the rear surface 2b of the glass substrate 2. The heat resistant resin layer 4 includes a silicone resin. The silicone resin is cross-linked by at least one kind of cross-linking agent selected from the group comprising a phenyltrialkoxysilane, a methyltrialkoxysilane and a tetraalkoxysilane.SELECTED DRAWING: Figure 1

Description

The present invention relates to a top plate for a cooker and a method for manufacturing the top plate for a cooker.

A heat-resistant glass substrate made of crystallized glass or borosilicate glass having a low coefficient of thermal expansion is used for a top plate for a cooker such as an electromagnetic cooker, a radiant heater cooker, or a gas cooker. The glass substrate of such a top plate for a cooker has a cooking surface and a back surface located on the inner side of the cooker.

On the back surface of the glass substrate in the top plate for a cooker, a painting film or a light-shielding layer is generally formed for the purpose of improving the design or concealing the structure inside the cooker. Further, a heat-resistant resin layer is formed on the painting film and the light-shielding layer for the purpose of further enhancing the internal hiding property and heat resistance. Patent Document 1 describes a heat-resistant resin layer containing a silane coupling agent as such a heat-resistant resin layer.

Japanese Unexamined Patent Publication No. 2010-40171

By the way, the top plate for a cooker may be adhered to the cooker by using an adhesive such as a silicone adhesive on the back surface of the top plate. Further, a temperature sensor (thermocouple) for acquiring temperature information may be attached to the heated portion on the back surface of the top plate using an adhesive such as a silicone adhesive. However, these adhesives may evaporate when heated to high temperatures by a heat source. As a result, the evaporation material that has exuded to the painting layer, the light-shielding layer, the heat-resistant resin layer, etc. on the glass substrate side is easily noticeable as a stain when viewed from the cooking surface side, and the aesthetic appearance of the top plate may be impaired. is there.

Patent Document 1 describes a heat-resistant resin layer containing a silane coupling agent. The silane coupling agent prevents deterioration (generation of cracks) of the heat-resistant resin layer and softens and spreads at a high temperature. Even if it is possible to prevent the agent from penetrating into the light-shielding layer through the gaps between the heat-resistant resin layers, there is a problem that stains due to the evaporated adhesive cannot be sufficiently suppressed. Further, when an amine-based silane coupling agent or the like is used, there is also a problem that the heat-resistant resin layer is discolored by heating.

An object of the present invention is to provide a cooking top plate and a method for manufacturing the cooking top plate, which are less likely to cause stains due to the evaporated adhesive and are excellent in aesthetics when viewed from the cooking surface side. is there.

The top plate for a cooker according to the present invention has a glass substrate having a cooking surface on which a cooking utensil is placed and a back surface opposite to the cooking surface, and a heat-resistant resin layer arranged on the back surface of the glass substrate. The heat-resistant resin layer contains a silicone resin, and the silicone resin is crosslinked with at least one cross-linking agent selected from the group consisting of phenyltrialkoxysilane, methyltrialkoxysilane, and tetraalkoxysilane. It is characterized by being.

In the present invention, it is preferable to further provide an inorganic light-shielding layer provided between the glass substrate and the heat-resistant resin layer.

The method for producing a top plate for a cooker according to the present invention is a method for producing a top plate for a cooker configured according to the present invention, wherein a silicone resin precursor and a phenyltrialkoxysilane are formed on the back surface of the glass substrate. The paste is coated by a step of applying a paste containing at least one cross-linking agent selected from the group consisting of methyltrialkoxysilane and tetraalkoxysilane, and by heating the glass substrate to which the paste is applied. It is characterized by comprising a step of drying and cross-linking the silicone resin precursor with the cross-linking agent.

In the present invention, the ratio of the cross-linking agent to the silicone resin precursor is preferably 100: 0.2 to 100: 30 in terms of mass ratio.

According to the present invention, it is possible to provide a cooking top plate and a method for manufacturing the cooking top plate, which are less likely to cause stains due to the evaporated adhesive and are excellent in aesthetics when viewed from the cooking surface side. it can.

It is a schematic cross-sectional view which shows the top plate for a cooker which concerns on one Embodiment of this invention. It is a schematic cross-sectional view which shows the structure which attached the temperature sensor to the back surface of the top plate for a cooker which concerns on one Embodiment of this invention.

Hereinafter, preferred embodiments will be described. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. Further, in each drawing, members having substantially the same function may be referred to by the same reference numerals.

FIG. 1 is a schematic cross-sectional view showing a top plate for a cooker according to an embodiment of the present invention. As shown in FIG. 1, the cooker top plate 1 (hereinafter, “cooker top plate 1” is simply referred to as “top plate 1”) includes a glass substrate 2. The glass substrate 2 has a cooking surface 2a and a back surface 2b facing each other. The cooking surface 2a is a surface on which cooking utensils such as a pot and a frying pan are placed. The back surface 2b is a surface facing the light source and the heating device on the inner side of the cooker. Therefore, the cooking surface 2a and the back surface 2b are in a front-to-back relationship.

The glass substrate 2 transmits at least a part of light at a wavelength of 450 nm to 700 nm. The glass substrate 2 may be colored and transparent, but is preferably colorless and transparent from the viewpoint of further enhancing the aesthetic appearance of the top plate 1. In the present specification, "transparent" means that the light transmittance in the visible wavelength range in the wavelength range of 450 nm to 700 nm is 70% or more.

In the top plate 1, heating and cooling are repeated. Therefore, the glass substrate 2 preferably has high heat resistance and a low coefficient of thermal expansion. Specifically, the softening temperature of the glass substrate 2 is preferably 700 ° C. or higher, more preferably 750 ° C. or higher. The average coefficient of linear thermal expansion of the glass substrate 2 at 30 ° C. to 750 ° C. ^{is preferably in the range of −10 × 10 −7} / ° C. to + 60 × 10 ⁻⁷ / ° C., preferably −10 × 10 ^−7. more preferably in the range of ^{/ ℃ ~ + 50 × 10 -7} / ℃, and even more preferably within the range of ^{-10 × 10 -7 / ℃ ~ +} 40 × 10 -7 / ℃. Therefore, the glass substrate 2 preferably has a high glass transition temperature and is made of low-expansion glass or low-expansion crystallized glass. Specific examples of the low-expansion crystallized glass include "N-0" manufactured by Nippon Electric Glass Co., Ltd. As the glass substrate 2, borosilicate glass or the like may be used.

The thickness of the glass substrate 2 is not particularly limited. The thickness of the glass substrate 2 can be appropriately set according to the light transmittance and the like. The thickness of the glass substrate 2 can be, for example, about 2 mm to 6 mm.

An inorganic light-shielding layer 3 is provided on the back surface 2b of the glass substrate 2. Further, a heat-resistant resin layer 4 is provided on the inorganic light-shielding layer 3. In the present embodiment, the heat-resistant resin layer 4 is formed on the entire back surface 2b of the glass substrate 2.

The inorganic light-shielding layer 3 is a light-shielding layer provided for the purpose of concealing the structure inside the cooker. Therefore, by providing the inorganic light-shielding layer 3 together with the heat-resistant resin layer 4, the structure inside the cooker can be more effectively concealed when viewed from the cooking surface 2a side, and the aesthetic appearance of the top plate 1 can be further enhanced. Can be done.

The inorganic light-shielding layer 3 is not particularly limited as long as it is made of an inorganic substance and has a low visible light transmittance. The inorganic light-shielding layer 3 can be formed of, for example, a layer containing an inorganic pigment powder and glass. In this case, as the inorganic pigment powder, for example, a Cu—Cr—Mn-based black inorganic pigment can be used. Further, as the glass, for example, B ₂ O _3- SiO ₂ system glass powder can be used. The inorganic light-shielding layer 3 can also be formed of a metal film such as titanium.

In the present embodiment, the inorganic light-shielding layer 3 is a porous film containing an inorganic pigment powder and glass. As described above, the inorganic light-shielding layer 3 is preferably a porous film, but may be a dense film having substantially no voids. If the inorganic light-shielding layer 3 is a dense film, the evaporated adhesive is less likely to seep out to the glass substrate 2 side, and is less noticeable as stains when viewed from the cooking surface 2a side.

The thickness of the inorganic light-shielding layer 3 is not particularly limited. The thickness of the inorganic light-shielding layer 3 can be appropriately set according to, for example, the light transmittance of the inorganic light-shielding layer 3, the mechanical strength, the coefficient of thermal expansion, and the like. The inorganic light-shielding layer 3 usually has a coefficient of thermal expansion different from that of the glass substrate 2. Therefore, the inorganic light-shielding layer 3 may be damaged by repeated heating and cooling.

From the viewpoint of further suppressing this damage, the inorganic light-shielding layer 3 is preferably thin. The thickness of the inorganic light-shielding layer 3 is preferably in the range of 1 μm or more and 15 μm or less, and more preferably in the range of 2 μm or more and 10 μm or less.

The method for forming the inorganic light-shielding layer 3 is not particularly limited. The inorganic light-shielding layer 3 can be formed, for example, by the following method.

First, a solvent is added to a mixed powder of an inorganic pigment powder and a glass powder to form a paste. The obtained paste is applied onto the back surface 2b of the glass substrate 2 by a screen printing method or the like, and dried. After that, the inorganic light-shielding layer 3 can be formed by firing. The firing temperature and firing time can be appropriately set according to the composition of the glass powder used. The firing temperature can be, for example, about 200 ° C. to 900 ° C. The firing time can be, for example, about 10 minutes to 1 hour.

When the inorganic light-shielding layer 3 is made of a metal film, it can be formed by a sputtering method, a CVD method, or the like.

The heat-resistant resin layer 4 contains a silicone resin. In the present embodiment, the silicone resin is crosslinked with at least one cross-linking agent selected from the group consisting of phenyltrialkoxysilane, methyltrialkoxysilane and tetraalkoxysilane.

As described above, in the top plate 1 of the present embodiment, the silicone resin contained in the heat-resistant resin layer 4 provided on the back surface 2b side of the glass plate 2 is crosslinked by the above-mentioned cross-linking agent, so that the cooking surface 2a When viewed from the side, stains due to the evaporated adhesive are unlikely to occur, and it is excellent in aesthetics. This point will be described in more detail below with reference to FIG.

As shown in FIG. 2, a temperature sensor 5 (thermocouple) for acquiring temperature information may be attached to the heated portion of the back surface 2b of the top plate 1 by using an adhesive 6 such as a silicone adhesive. is there. Such an adhesive 6 may evaporate when heated at a high temperature by a heat source or the like. In the conventional top plate, the evaporation of this adhesive may, for example, pass through the heat-resistant resin layer and seep out to the inorganic light-shielding layer side of the glass substrate. Therefore, when viewed from the cooking surface side, it is easily noticeable as a stain, and the aesthetic appearance of the top rate may be impaired.

On the other hand, in the top plate 1 of the present embodiment, the silicone resin contained in the heat-resistant resin layer 4 is crosslinked by the above-mentioned cross-linking agent, so that the silicone resin forms a net-like network and the heat-resistant resin. The layer 4 can be a dense layer. Therefore, it is difficult for the evaporated adhesive 6 to permeate through the heat-resistant resin layer 4, and it is possible to prevent the evaporated adhesive 6 from seeping out to the inorganic light-shielding layer 3 side close to the glass substrate 2. Therefore, in the top plate 1, when viewed from the cooking surface 2a side, it is possible to make it difficult for stains due to the adhesive to occur, and it is possible to improve the aesthetic appearance.

When the above alkoxysilane is used as the cross-linking agent, since it has many alkoxy groups that dehydrate and condense with the silicone, it easily functions as a cross-linking point between the silicones, and the heat-resistant resin layer 4 can be made into a more dense layer. Therefore, it is possible to make it more difficult for stains caused by the adhesive or the like of the top plate 1 to occur, and it is possible to further improve the aesthetic appearance.

The alkoxy group of alkoxysilane is preferably a methoxy group, an ethoxy group, a propoxy group, or a butoxy group, more preferably a methoxy group or an ethoxy group, and even more preferably a methoxy group. One of these alkoxy groups may be used alone, or a plurality of types may be used in combination.

Further, the above-mentioned alkoxysilane may be used alone or in combination of two or more.

The cross-linking agent preferably contains one selected from the group of phenyltrimethoxysilane, phenyltriethoxysilane, methyltrimethoxysilane and tetraethoxysilane among the above alkoxysilanes, and contains phenyltrimethoxysilane. Is more preferable.

The silicone resin is not particularly limited, but is preferably one having high heat resistance. The silicone resin is preferably, for example, a silicone resin in which the functional group directly bonded to the silicon atom is at least one of a methyl group and a phenyl group. In this case, discoloration of the heat-resistant resin layer 4 when the top plate 1 becomes hot can be suppressed more effectively. Of these, a silicone resin in which the functional group directly bonded to the silicon atom is a methyl group is more preferable.

The content of the silicone resin in the heat-resistant resin layer 4 is not particularly limited, but is preferably 20% by mass or more, more preferably 30% by mass or more, preferably 70% by mass or less, and more preferably 60% by mass or less. When the content of the silicone resin is at least the above lower limit value, the heat resistance and impact resistance of the top plate 1 can be further enhanced. Further, when the content of the silicone resin is not more than the above upper limit value, the mechanical strength of the top plate 1 can be further increased.

The heat-resistant resin layer 4 may further contain an inorganic pigment powder. In this case, the structure inside the cooker can be concealed more effectively.

The inorganic pigment powder includes, for example, _{a white pigment powder such as TiO 2} powder, ZrO ₂ powder, and ZrSiO ₄ powder, a blue or green inorganic pigment powder containing Co, a green inorganic pigment powder containing Co, and Ti-Sb-Cr. Examples thereof include Ti-Ni-based yellow inorganic pigment powders, Co-Si-based red inorganic pigment powders, brown inorganic pigment powders containing Fe, and black inorganic pigment powders containing Cu.

Specific examples of the blue inorganic pigment powder containing Co include Co-Al-based and Co-Al-Ti-based inorganic pigment powders. Specific examples of the Co-Al-based inorganic pigment powder include CoAl ₂ O ₄ powder. Specific examples of the Co-Al-Ti-based inorganic pigment powder include CoAl ₂ O ₄ : TiO ₂ : Li ₂ O powder.

Specific examples of the green inorganic pigment powder containing Co include Co—Al—Cr-based and Co—Ni—Ti—Zn-based inorganic pigment powders. Specific examples of the inorganic pigment powder Co-Al-Cr-based, Co (Al, _Cr), etc. 2 _{O 4} powder. Specific examples of the Co-Ni-Ti-Zn-based inorganic pigment powder include (Co, Ni, Zn) ₂ TiO ₄ powder.

Specific examples of the brown inorganic pigment powder containing Fe include Fe—Zn-based inorganic pigment powder. Specific examples of the Fe—Zn-based inorganic pigment powder include (Zn, Fe) Fe ₂ O ₄ powder.

Specific examples of the black inorganic pigment powder containing Cu include Cu—Cr-based inorganic pigment powder. Specific examples of the Cu—Cr-based inorganic pigment powder include Cu (Cr, Mn) ₂ O ₄ powder.

These inorganic pigment powders may be used alone or in combination of two or more.

The content of the inorganic pigment powder in the heat-resistant resin layer 4 is not particularly limited, but is preferably 20% by mass or more, more preferably 30% by mass or more, preferably 70% by mass or less, and more preferably 60% by mass or less. .. When the content of the inorganic pigment powder is within the above range, the structure inside the cooker can be more effectively concealed.

The thickness of the heat-resistant resin layer 4 is not particularly limited. The thickness of the heat-resistant resin layer 4 is preferably 5 μm or more, more preferably 10 μm or more, preferably 30 μm or less, and more preferably 25 μm or less. When the thickness of the heat-resistant resin layer 4 is within the above range, stains caused by the adhesive or the like on the top plate 1 can be made less likely to occur, and the aesthetic appearance can be further improved.

The method for forming the heat-resistant resin layer 4 is also not particularly limited. First, a paste containing a silicone resin precursor, the above-mentioned cross-linking agent, and, if necessary, a solvent or an inorganic pigment powder is prepared. Next, the prepared paste is applied directly onto the inorganic light-shielding layer 3 and dried. Thereby, the silicone resin precursor can be crosslinked to form the heat-resistant resin layer 4. Depending on the composition of the heat-resistant resin layer 4, the top plate 1 may be obtained by firing after drying.

The coating speed and viscosity of the paste can be appropriately set according to the content of the inorganic pigment contained in the heat-resistant resin layer 4. For example, when the content of the inorganic pigment in the heat-resistant resin layer 4 is high, it is preferable to lower the viscosity of the silicone resin precursor and slow down the coating speed of the silicone resin precursor.

The silicone resin precursor is not particularly limited, but is preferably one having high heat resistance. The silicone resin precursor is preferably, for example, a silicone resin in which the functional group directly bonded to the silicon atom is at least one of a methyl group and a phenyl group. In this case, discoloration of the heat-resistant resin layer 4 when the top plate 1 becomes hot can be suppressed more effectively. Of these, a silicone resin in which the functional group directly bonded to the silicon atom is a methyl group is more preferable.

The ratio of the cross-linking agent to the silicone resin precursor is not particularly limited, but preferably the silicone resin precursor: cross-linking agent is 100: 0.2 to 100:30, more preferably 100: 5 to 100: in terms of mass ratio. 20. When the ratio of the cross-linking agent to the silicone resin precursor is at least the above lower limit value, the heat-resistant resin layer 4 can be made into a denser layer. Therefore, it is possible to make it more difficult for stains caused by the evaporated adhesive of the top plate 1 to occur, and it is possible to further improve the aesthetic appearance. Further, when the ratio of the cross-linking agent to the silicone resin precursor is not more than the above upper limit value, it is possible to further suppress the heat-resistant resin layer 4 from becoming hard or brittle, and cracks in the heat-resistant resin layer 4 are further suppressed. It can be made less likely to occur. Therefore, even in this case, it is possible to make it more difficult for stains caused by the adhesive or the like of the top plate 1 to occur, and it is possible to further improve the aesthetic appearance.

The firing temperature of the applied paste can be, for example, 200 ° C. or higher and 450 ° C. or lower. The firing time can be, for example, 10 minutes or more and 1 hour or less.

In the above embodiment, the inorganic light-shielding layer 3 is provided between the glass substrate 2 and the heat-resistant resin layer 4, but the inorganic light-shielding layer 3 may not be provided. Therefore, the heat-resistant resin layer 4 may be provided directly above the glass substrate 2.

Further, in the above embodiment, the heat-resistant resin layer 4 is formed on the entire back surface 2b of the glass substrate 2, but the heat-resistant resin layer 4 is formed on a part of the back surface 2b of the glass substrate 2. May be. For example, the heat-resistant resin layer 4 may be provided below the adhesive portion of the temperature sensor 5 attached to the heated portion on the back surface 2b of the top plate 1.

Further, in the above embodiment, the film is not formed on the cooking surface 2a of the glass substrate 2, but a decorative film or the like is formed on the cooking surface 2a for the purpose of improving the aesthetic appearance and displaying the heater position. May be formed.

Further, on the back surface 2b side of the glass substrate 2, an adhesion layer or the like may be formed between the heat-resistant resin layer 4 and the inorganic light-shielding layer 3, and the heat-resistant resin layer 4 may be formed on the heat-resistant resin layer 4. A protective layer or the like may be formed. Alternatively, another heat-resistant resin layer may be formed on the heat-resistant resin layer 4.

Hereinafter, the present invention will be described in more detail based on examples. However, the following examples are merely examples. The present invention is not limited to the following examples.

(Example 1)
First, the glass powder, the Cu—Cr-based black inorganic pigment powder, and the resin binder are mixed at a mass ratio (glass powder: inorganic pigment powder: resin binder) of 3: 7:10. And made a paste.

Next, this paste is used as a glass substrate on a transparent crystallized glass plate (manufactured by Nippon Electric Glass Co., Ltd., trade name "N-0", average coefficient of linear thermal expansion at 30 ° C to 750 ° C: 0.5 × ^10-7 / (° C., thickness: 4 mm), screen printing was performed on the entire surface so that the thickness was 5 μm. Then, it was dried by heating at 830 ° C. for 10 minutes. As a result, an inorganic light-shielding layer was formed on the glass substrate.

Next, the mass ratios of the silicone resin precursor, phenyltrimethoxysilane (PTMS) as a cross-linking agent, Cu-Fe-Mn-based black inorganic pigment powder, extender pigment (talc), and organic solvent, respectively. (Silicone resin precursor: PTMS: inorganic pigment powder: extender pigment: organic solvent) at a ratio of 34.3: 0.2: 19.9: 19.9: 25.7 (silicone resin precursor in a dry coating film). A paste was prepared by mixing so that the ratio of PTMS to the body was 100: 0.6) in terms of mass ratio. This paste was screen-printed on the entire inorganic light-shielding layer so as to have a thickness of 15 μm. Then, it dried by heating at 300 degreeC for 20 minutes. As a result, a heat-resistant resin layer was formed on the inorganic light-shielding layer to obtain a top plate.

(Examples 2 to 3)
A top plate was obtained in the same manner as in Example 1 except that the content of the cross-linking agent was changed as shown in Table 1.

(Examples 4 to 5)
A top plate was obtained in the same manner as in Example 1 except that the type and content of the cross-linking agent were changed as shown in Table 1.

(Comparative Example 1)
A top plate was obtained in the same manner as in Example 2 except that 3-aminopropyltrimethoxysilane as a silane coupling agent was used instead of the cross-linking agent.

(Comparative Example 2)
A top plate was obtained in the same manner as in Example 1 except that no cross-linking agent was used.

(Evaluation)
1.5 g of a silicone adhesive was applied onto the heat-resistant resin layers of the top plates obtained in Examples 1 to 5 and Comparative Examples 1 and 2, respectively. After applying the silicone adhesive, the top plate was placed on a hot plate at 230 ° C. with the cooking surface side, which is the surface on the top plate not provided with the heat-resistant resin layer, facing down. After the placement, the top plate was picked up at predetermined time intervals, and the presence or absence of stains was visually confirmed while irradiating light from the cooking surface side, and the time until the stains were generated was measured.

The results are shown in Table 1.

As is clear from Table 1, in each of the samples of Examples 1 to 5 containing the cross-linking agent, the time until stains were formed was as long as 600 hours or more, and stains due to the evaporated adhesive were less likely to occur. On the other hand, in each of the samples of Comparative Examples 1 and 2, the time until stains were formed was as short as 300 hours or less, and stains due to the adhesive evaporated in a short time were likely to occur.

1 ... Top plate for cooker 2 ... Glass substrate 2a ... Cooking surface 2b ... Back surface 3 ... Inorganic light-shielding layer 4 ... Heat-resistant resin layer 5 ... Temperature sensor 6 ... Adhesive

Claims (4)

A glass substrate having a cooking surface on which cooking utensils are placed and a back surface opposite to the cooking surface.
A heat-resistant resin layer arranged on the back surface of the glass substrate,
With
The heat-resistant resin layer contains a silicone resin and contains
A top plate for a cooker in which the silicone resin is crosslinked with at least one cross-linking agent selected from the group consisting of phenyltrialkoxysilane, methyltrialkoxysilane and tetraalkoxysilane. The top plate for a cooker according to claim 1, further comprising an inorganic light-shielding layer provided between the glass substrate and the heat-resistant resin layer. The method for manufacturing a top plate for a cooker according to claim 1 or 2.
A step of applying a paste on the back surface of the glass substrate, which comprises a silicone resin precursor and at least one cross-linking agent selected from the group consisting of phenyltrialkoxysilane, methyltrialkoxysilane and tetraalkoxysilane. When,
A step of drying the paste by heating the glass substrate to which the paste is applied and cross-linking the silicone resin precursor with the cross-linking agent.
A method of manufacturing a top plate for a cooker. The method for producing a top plate for a cooker according to claim 3, wherein the ratio of the cross-linking agent to the silicone resin precursor is 100: 0.2 to 100:30 in terms of mass ratio.

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