JPH0630818Y2 - Electric heating glass - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention forms a surface heating element on a glass surface for the purpose of preventing dew condensation, melting adhering ice and snow, and defrosting and defrosting.
In addition, the present invention relates to an electrothermal glass for improving electric durability.

[Prior Art] Conventionally, since it is necessary to prevent dew condensation and melt adhering ice and snow,
There were various types of electrothermal glass in which a transparent conductive coating as a surface heating element was formed on the glass surface.

FIG. 7 shows an example of such a conventional technique.

That is, in the laminated glass in which the outer glass sheet 50 and the inner glass sheet 52 are joined by the laminated intermediate film 51 made of polyvinyl butyral or the like, the outer glass sheet 50 and the laminated intermediate film 51 are joined together.
At the peripheral edge of the boundary surface with the
However, a transparent conductive coating 53 as a surface heating element is formed on the same boundary.

On the other hand, a bus bar 55 for power supply is laminated on the colored coating layer 54, and the transparent conductive coating 53 is energized through the bus bar 55 to heat the glass surface.

However, as shown in FIG. 7, the bus bar 55 has a colored coating layer.
A part is extended from 54 (extension part 56)
Therefore, most of the coating film breakage that occurs during energization occurs at the boundary between the bus bar print 55 and the transparent conductive film 53.

At such a boundary, it is sufficient to improve the boundary. Therefore, most of the measures against the film breakage are related to the bus bar, for example, the one in which the edge is tapered (Actual No. Sho 62-457). JP-A-62-456), a two-stage bus bar (Japanese Utility Model Laid-Open No. 62-456), a protective print (Japanese Utility Model Laid-Open No. 62-99191), and the like are known.

[Problems to be Solved by the Invention] Conventionally, as shown in FIG. 7, the bus bar 55 partially protrudes from the colored coating layer 54.

Further, the adhered state of both of them is not always sufficient.

Therefore, in response to this, a considerable potential difference is generated between the two, which often leads to film breakage in a form induced by the potential difference.

Therefore, the above-mentioned prior art was devised to improve the boundary between the bus bar 55 and the transparent conductive film 53.

That is, these prior arts have the bus bar 55 and the transparent conductive film.
Progress will be made in improving the boundaries of 53 and preventing film breakage between them.

On the other hand, the fact that the bus bar partially protrudes from the colored coating layer means that the color of the bus bar can be clearly seen from the outside of the vehicle, which may violate domestic safety standards.

In view of these social situations, there has been a demand to completely hide the bus bar on the colored coating layer.

However, the conventional technology (including the above-mentioned prior art with improvement) does not consider the case where the bus bar is entirely on the colored coating layer, and thus it can be said that the performance of the electrothermal glass is insufficient.

That is, as shown in the comparative example (Fig. 10), in the electrothermal glass, when all the busbars were on the colored coating layer, the colored coating layer and the transparent layer were transparent when energized after being left at high temperature (80 ° C for 28 days). The result is that the transparent conductive film is cut off at the portion where the conductive film is in contact, particularly near the end of the colored coating layer closer to the center of the glass plate.

The inventors investigated the cause and found that pigment particles of about 1 μm existed on the colored coating layer after firing, and the film thickness of the transparent conductive coating was as thin as 0.1 μm. It has been clarified that this occurs, and in particular, the unevenness due to the pigment particles is remarkable at the end of the colored coating layer near the center of the glass plate.

As the coloring coating layer, a ceramic color print, or a coloring layer formed by printing an organic paint is used. The ceramic color print is a glass frit,
It is composed of pigments and other additives. Among them, the glass frit melts, so that the adhesive strength with glass can be increased and baked.

However, at this time, there is no problem because the glass frit melts and becomes smooth by firing, but the larger the particle size of components other than the glass frit or the insufficient firing, the more it is on the ceramic color print, that is, the surface of the colored coating layer. The unevenness becomes remarkable, and there arises a problem that electric current distortion occurs in the colored coating layer and resistance between terminals increases due to a bonding process of the laminated glass. This causes the film breakage at the boundary between the colored coating layer and the transparent conductive coating, as described above.

Therefore, the first object of the present invention is to prevent the film breakage by covering the irregularities due to the pigment component of the colored coating layer when the bus bar is on the colored coating layer.

Further, it is an object of the present invention to provide electric heating glass which is not only a countermeasure against film breakage but also improves the durability against electric current, and has good performance and appearance.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following configuration.

That is, according to the present invention, a transparent conductive coating (13) is formed on a surface of a laminated glass, which is formed by joining two glass plates through an intermediate film, to the intermediate film, and a transparent conductive film (13) is formed on the bonding surface. In the electrothermal glass for heating the glass by energizing the coating through the bus bar (15), a colored coating layer such as a ceramic color print is formed on the peripheral portion of the surface of the one glass plate in contact with the intermediate film. 14) is formed, the bus bar (15) is formed without protruding onto the colored coating layer (14), and the protective layer is formed so as to cover the end of the colored coating layer (14) closer to the center of the glass plate. The present invention provides an electrothermal glass characterized in that (16) is formed and a transparent conductive film (13) is formed thereon.

The present invention is characterized in that a specific protective layer 16, that is, a protective layer 16 providing a substantially smooth surface is formed so as to cover the end portion of the colored coating layer 14 closer to the center of the glass plate.
The protective layer fills the irregularities due to the pigment component or the like on the surface of the colored coating layer, and solves the conventional problems. At the end of the colored coating layer after firing, components other than the glass frit, for example pigment particles, tend to be exposed without being almost covered by the layer formed by welding the glass frit contained in the colored coating layer. Is recognized, and it is considered that unevenness is generated on the end surface. In the portion other than the end portion of the colored coating layer, most of the particles of the components other than the glass frit are covered with a layer formed by welding the glass frit contained in the colored coating layer. It is considered that the difficulty due to the unevenness is less likely to occur than at the edge of the layer.

Therefore, it is the colored coating layer end that is most prone to film breakage of the transparent conductive coating. In the present invention, the protective layer that fills the irregularities of the end and provides a substantially smooth surface.
16 is formed.

The protective layer 16 may fill the irregularities at the ends of the colored coating layer so as to provide a “practically” smooth surface to the extent that the transparent conductive coating 13 does not break. With such a protective layer 16, the unevenness of the colored coating layer 14 is such that the convex portions thereof have a more rounded shape than the acute angle shape, the number of the convex portions is smaller, and the depth of the concave and convex portions is shallower. Is preferred. “Implementable”
The smooth surface means that the surface of the transparent conductive coating 13 does not cause deterioration such as film breakage, and the shape of the convex portions, the number of convex portions, the depth of the irregularities, and the density of the irregularities. It is not always easy to specify numerical values because it is determined comprehensively considering various factors such as. Taking the maximum height of the unevenness as an example, the result is as follows. If the transparent conductive film 13 is formed with a film thickness of X (μm), the maximum surface height (R _max ) given by the protective layer 16
(The “maximum height” here means the maximum height (R _max ) defined in JIS B 0601-1982)) is 9 × X
(Μm) or less, preferably 5 × X (μm) or less, particularly preferably X (μm) or less.

When the protective layer 16 fills the irregularities of the colored coating layer 14 and becomes a certain thickness or more, the surface smoothness becomes constant regardless of the thickness. On the other hand, if the protective layer 16 is too thick, it may be noticeable in appearance. Therefore, the thickness of the protective layer 16 is preferably 5 μm or less.

For example, in the colored coating layer 14, pigment particles having a particle size of about 1 μm are scattered, and a transparent conductive coating is formed on the colored coating layer 14 by about 0.1 μm.
In the case of being formed with a thickness of μm, the above colored coating layer
The maximum height of the surface of the protective layer 16 formed so as to cover the end portions of 14 is preferably about 0.1 μm or less.

In the protective layer 16 that provides a substantially smooth surface of the present invention,
In order to make the protective layer 16 inconspicuous in appearance, the refractive index of the protective layer is
It is preferably composed of a transparent substance of 2.0 or less. A refractive index of 2.0 or less, particularly preferably in the range of 1.4 to 1.6,
By making the refractive index of the glass that is the substrate close, it is preferable that the occurrence of interference by the protective layer is suppressed and the appearance becomes inconspicuous. As the substance having such a refractive index of 2.0 or less,
For example, SnO ₂ (refractive index n = 2.0), SiO ₂ (n = 1.5), Zr
O ₂ (n = 2.0), In ₂ O ₃ · SnO ₂ (n = 1.9) and other metal oxides alone or in a mixture, or TiO ₂ (n = 2.3), Ta ₂ O ₅
A high refractive index oxide such as (n = 2.1) and a complex oxide having the above low refractive index oxide in an appropriate ratio can be given.

The method of forming the protective layer 16 in the present invention includes the following four methods. First, a method in which a glass frit is mixed with a thickener, applied by printing or the like, baked and baked, and secondly, a metal acetylacetonate of a metal oxide formed as the protective layer 16, an alkoxide, or the like. A solution (hereinafter referred to as a metal salt solution) in which a metal salt such as an organic metal salt, a halide, an acetate salt, nitric acid or a chelate compound is dissolved in an alcohol salt, an aromatic compound such as benzene, or a solvent such as a chlorine-based solvent. After coating, a method of thermally decomposing to form a metal oxide, thirdly, a metal alkoxide of the metal oxide, water for hydrolyzing the metal alkoxide, and a solvent compatible with the metal alkoxide and water. Solution dissolved in a mixed solution with alkoxide as
A metal alkoxide solution), and heating and baking to form a metal oxide film by the sol-gel method,
Fourth, a method of forming a metal oxide film by a sol-gel method by applying a sol (hereinafter referred to as a metal oxide sol) in which fine particles of a metal oxide are dispersed as colloidal particles in water or an organic solvent, and heating and drying. Is.

The glass frit used in the first method may be the same as the glass frit contained in the ceramic color print 14 or the bus bar 15, and the melting point of the glass frit is equal to or lower than the bending temperature (600 to 640 ° C.) of the laminated glass. Is desirable. This is because the glass frit needs to have a melting point equal to or lower than the firing temperature in order to bring the surface close to a smooth surface by firing.

Further, it is preferable that the glass frit is printed by a screen printing method in the same manner as the ceramic color print or the bus bar print in the process, and is baked together at the time of baking.

It is preferable that the glass frit is mixed with a thickener or the like, adjusted to have a viscosity suitable for screen printing, for example, about 1000 to 20000 cp (centipoise), and screen printed.

Since the main component of the layer formed by welding glass frit is silicon oxide, it is transparent and has a refractive index of about 1.5, which is preferable as the protective layer of the present invention.

In the second to fourth methods described above, as a method for applying a metal salt solution, a metal alkoxide solution, a metal oxide sol or the like (including a substance that can be converted into a metal oxide by firing), a screen printing method, A spray method, a roll coater method, a meniscus coater method, a printing method, a brush coating method and the like are possible.

Among the above methods using the second to fourth liquids, the third method in which a liquid containing a metal alkoxide is fired to form is preferable because it can be applied by a screen printing method that is simple in the manufacturing process and is therefore efficient. In this case, the metal alkoxide may be appropriately adjusted to obtain the desired metal oxide. And containing such desired metal alkoxide,
Viscosity preferred for screen printing with thickeners, eg 10
It is desirable to form a protective layer 16 of the present invention by screen-printing a liquid having a viscosity adjusted to about 00 to 20000 cp (centipoise) and firing it.

Furthermore, by placing one end of the protective layer 16 in the gradation print of the ceramic color print, the effect is more inconspicuous in appearance and does not cause a feeling of strangeness.

Above, these details are shown in the accompanying drawings,
This will be described in Examples.

[Operation] With the above-mentioned configuration, the protective layer 16 is seized by firing, the boundary between the ceramic color print 14 and the glass,
The surface of the ceramic color print 14, the boundary between the bus bar 15 and the ceramic color print 14, and the part of the bus bar, which is the base of the transparent conductive film 13, is smoothed,
Reduce unevenness.

Therefore, even if the transparent conductive film 13 that is much thinner than the ceramic color print 14 is coated, there is no local resistance increase, and film breakage can be prevented.

[Embodiment] An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a partially enlarged vertical sectional view of an electric heating glass according to an embodiment of the present invention.

First, the electrothermal glass forms a laminated glass in which an outer glass sheet 10 and an inner glass sheet 12 are joined by a laminated intermediate film 11 made of polyvinyl butyral or the like.

A transparent conductive coating 13 as a surface heating element is formed on one of the glass-bonded surfaces of the laminated glass (the glass-bonded surface of the outer glass 10 in FIG. 1), and the ceramic plays a role of concealment. A bus bar 15 for power supply is placed and laminated on the color print 14 without protruding from the color print 14, and the transparent conductive film 13 is energized via the bus bar to heat the glass surface.

Further, the most important feature of the present invention is the insertion of the protective layer boundary, which first covers the end of the ceramic color print 14 closer to the center of the glass plate, and further, the ceramic color print 14 which is the base of the transparent conductive film 13. And covering the boundary portion of the bus bar 15 and the ceramic color print 14, further covering a part of the bus bar 15 which is the base of the transparent conductive coating 13 to make the surface smooth, and locally cause a film breakage. Prevents resistance rise and improves current durability. For easy understanding, FIG. 2 shows a plan view of the outer plate, and FIG. 3 shows a cross section taken along the line AA 'in FIG.

As shown in FIG. 3, a ceramic color print 14
It is also preferable to form a taper on the ceramic color print in the vicinity of the print edge 19 and to form the protective layer 16 thereon.

Further, it is effective to prevent film breakage of the transparent conductive film by making the edge 20 closer to the glass center of the surface portion of the protective layer 16 in contact with the transparent conductive film smaller so as to reduce the step.

The bus bar 15 used in the present invention is preferably silver paste containing silver and glass frit and the like, and any other suitable one can be used as long as the effects of the present invention can be sufficiently exhibited.

On the other hand, the ceramic color print 14 is a glass frit,
Appropriate methods such as mixing pigments such as CuO-Cr ₂ O ₃ , TiO ₂ , Fe ₂ O ₃ , CoO, and Cr ₂ O ₃ and fillers such as alumina and printing the ink are used.

Further, as a method for producing the protective layer, it is most efficient in terms of the production process that it is preferably applied by screen printing in the same manner as in ceramic color printing or bus bar printing, and then baked together.

Further, as described above, the print thickness of the protective layer is not limited as long as the protective layer provides a practically smooth surface. For example, the particle size of the pigment, which is a component of the ceramic color print, is usually 5
Taking into consideration that pigment particles having a particle size of ˜15 μm and having a size of about 1 μm are present even after firing, the film thickness after firing is about 0.
It can be said that it is preferable to set it in the range of 1 to 5 μm, especially about 1 μm. Also, if the thickness is more than 5 μm, the end portion of the protective layer becomes conspicuous and the appearance is not preferable. 0.
If it is less than 1 μm, a substantially smooth surface may not be provided, so 0.1 μm or more is preferable.

The ceramic color print is necessary because it is important in terms of concealing properties and appearance when the busbars are laminated, but it is necessary to smooth the print surface in order to improve current-carrying performance. In view of this, it can be said that the print thickness of the protective layer described above is optimum.

Further, the print width of the protective layer is, for various reasons described above,
1-3 from the in-plane bus bar edge 18 toward the glass edge 17
mm, a distance of 1 to 3 mm in the in-plane direction from the in-plane ceramic color print edge 19 is desirable.

The transparent conductive film is not particularly limited,
A multilayer film composed of a metal such as Ag or Au sandwiching a metal oxide such as SnO ₂ , ITO, ZnO, TiO ₂ on both sides, an ITO film, or SnO ₂ : F
A film, a SnO ₂ : Sb film, a single-layer film such as a ZnO: Al film is generally used, and a sheet resistance value is preferably 10Ω or less. Further, as the film thickness, a color tone in appearance and a spectral value (T _V , T _E , R _V , R
_Since it depends on _E ), it may be adjusted according to the purpose (the total film thickness is often 500 to 1000Å).

This transparent conductive coating 13 is provided on one side of the glass bonding surface, but is provided on the side surface of the laminated interlayer 11 inside the outer glass plate 10 so that ice, snow, etc. attached to the outer surface of the outer glass plate 10 can be easily thawed. It is better to have As a forming method thereof, an appropriate method such as a vacuum vapor deposition method or a sputtering method can be used.

In addition to the above, by containing one end (print edge) of the protective layer in the gradation print of the ceramic color print, it is possible to provide a good electrothermal glass without the protective layer being conspicuous in appearance. it can. An example thereof is shown in FIG. 5, and a CC 'sectional view thereof is shown in FIG. Reference numeral 14 is a colored coating layer such as a ceramic color print, and 24 is a foundation print of the colored coating layer.

Although FIG. 5 shows an example in which the ground print 24 is formed in a dot shape, other shapes may be used. It may be formed as a whole so as to be blurred from the ceramic color print edge 19 in the in-plane direction.

The protective layer 16 of the present invention covers the print edge 19 of the colored coating layer and prevents the transparent conductive coating 13 from being broken. Since sufficient conductivity is ensured in the portion of the transparent conductive coating 13 that is directly coated on the glass plate around the foundation print 24, film breakage hardly occurs at the edge of the foundation print 24. Since the print edge 20 of the protective layer 16 is inside the ground print 24, the protective layer is visually unnoticeable.

Since the present invention is configured as described above, it is possible to completely prevent the film breakage that has occurred in the past.

Example 1 A ceramic color print was screen-printed on the peripheral portion of the outer glass 50 as shown in FIG. 2 and pre-dried, and then an Ag paste for a bus bar was screen-printed as shown in FIG. 2 and pre-dried. As shown in FIG. 4, glass frit is mixed with a thickener, screen-printed, and then dried.
It was baked at 630 ° C., then laminated with an inner plate glass and subjected to bending.

The thickness of the ceramic color print after firing is 15 μm, the thickness of the bus bar is 20 μm, and the thickness of the protective layer formed by welding the glass frit is about 1 μm.
_{The maximum was} 0.1 μm or less. Next, a transparent conductive film (total film thickness of about 0.1 μm) having a structure of ZnO / Ag / ZnO is formed, and a fourth film is formed.
As shown in the figure, the laminated glass was formed by bonding it to the inner glass plate through the intermediate film. The resistance between the terminals of the laminated glass bus bar was 9.53Ω.

The resistance after holding this laminated glass at 80 ° C for 30 days was 9.26.
In Ω, no film breakage was observed even when electricity was applied. Electric current distortion did not occur.

Example 2 The protective layer of Example 1 was screen-printed with a sol-gel reaction solution containing a small amount of water obtained by diluting silicon alkoxide with alcohol instead of the glass frit, and then baked simultaneously with the ceramic color print and the bus bar. Formed.

The thickness of the protective layer after firing is 0.5 μm, and its surface has R _max.
Was about 0.2 μm. A laminated glass was formed in the same manner as in Example 1 except that the resistance between terminals was 11.3.
It was 1 Ω and 11.54 Ω after 30 days at 80 ° C, and no film breakage was observed even when current was applied. Electric current distortion did not occur.

Comparative Example The same procedure as in Example 1 was repeated except that no protective layer was formed.
A laminated glass as shown in Fig. 10 was formed. The initial resistance between terminals was 9.53Ω, but the resistance after leaving at 80 ° C for 30 days was
It was 11.63 Ω, and film breakage occurred when current was applied.

[Effects of the Invention] With the above-described structure, the invention has the following effects.

That is, by covering the ceramic color print and the bus bar, which are the base of the transparent conductive film, with a specific protective layer, the end of the ceramic color print near the center of the glass plate where the film breakage of the transparent conductive film is particularly noticeable. By covering
It is possible to prevent film breakage and increase in sheet resistance of the transparent conductive coating in this portion, and to suppress the occurrence of energization strain.

Therefore, even if a transparent conductive film that is much thinner than the ceramic color print is coated, there is no local resistance increase and film breakage can be prevented.

Furthermore, by printing the protective layer 16 also on the boundary between the bus bar 15 and the ceramic color print 14, the prevention of film breakage and the improvement of durability against electric current become more effective.

Further, by placing the print edge of the protective layer 16 away from the bus bar in the gradation print of the ceramic color print 14, it is possible to provide an electrically heated glass having a good appearance.

Furthermore, the refractive index of the protective layer is 2.0 or less, preferably 1.4 to 1.
By setting the range to 6 and approaching the refractive index of the glass that is the substrate, the occurrence of interference is reduced and an electrothermal glass having a good appearance is provided.

[Brief description of drawings]

FIG. 1 is a partially enlarged vertical sectional view of an electric heating glass for automobiles according to an embodiment of the present invention, FIG. 2 is a plan view of an outer glass sheet, and FIG.
FIG. 4 is a sectional view taken along the line AA 'in FIG. 2, and FIG. 4 is the first embodiment.
5 is a partial cross-sectional view of the electric heating glass of the present invention formed in FIGS. 2 and 3, FIG. 5 is a partial plan view of the electric heating glass of the present invention when a ground print of a colored coating layer is formed, and FIG. 5 is a sectional view taken along the line CC 'in FIG. 5, FIG. 7 is a partially enlarged vertical sectional view of a conventional example in which the bus bar partially protrudes from the colored coating layer, and FIG. 8 shows it in the bus bar or ceramic color print. FIG. 9 is a plan view of the outer sheet glass in the case where they are laminated without each other, FIG. 9 is a sectional view taken along the line BB ′ in FIG. 8, and FIG. 10 is a partial sectional view of the electrothermal glass formed in the comparative example.

Claims (9)

[Scope of utility model registration request] 1. A bus bar for power supply, wherein a transparent conductive film (13) is formed on the adhesive surface of one glass plate of laminated glass formed by joining two glass plates through an intermediate film to the intermediate film. (15)
In the electrothermal glass for heating the glass by energizing the coating through the glass, a colored coating layer such as a ceramic color print is provided on the peripheral portion of the surface of the one glass plate in contact with the intermediate film.
(14) is formed, the bus bar (15) is formed without protruding on the colored coating layer (14), and the end portion of the colored coating layer (14) closer to the center of the glass plate is covered so as to be protected. An electrothermal glass comprising a layer (16) and a transparent conductive coating (13) formed thereon. 2. A protective layer (16) is formed so as to cover an end of the colored coating layer (14) closer to the center of the glass plate and to provide a substantially smooth surface. Claim 1
The described electrothermal glass. 3. The electrothermal glass according to claim 1, wherein the protective layer (16) is made of a transparent substance having a refractive index of 2.0 or less. 4. The protective layer (16) is a metal oxide film formed by firing a liquid containing a substance capable of forming a metal oxide by firing. Electrothermal glass as described in the item. 5. The electrothermal glass according to claim 1, wherein the protective layer (16) is a layer formed by welding glass frit. 6. The electrothermal glass according to claim 1, wherein the protective layer (16) has a thickness of 5 μm or less. 7. A protective layer (16) is formed so as to cover the colored coating layer (14) in a region where the transparent conductive coating (13) overlaps with the colored coating layer (14). Claim 1
6. The electrothermal glass according to any one of 6 above. 8. The busbar (15) in the region where the transparent conductive coating (13) overlaps the colored coating layer (14) and the busbar (15).
And a protective layer (16) so as to cover the colored coating layer (14) and the bus bar (15) except for a portion where the transparent conductive coating (13) is in contact with
The electrothermal glass according to claim 1, wherein the electrothermal glass is formed. 9. Electric heating according to claim 1, characterized in that one end of the protective layer (16) is in the gradation print of the colored coating layer (14) such as a ceramic color print. Glass.