Vehicle glass

Abstract

The present invention pertains to a vehicle glass comprising a glass plate, a ceramic color layer formed on a surface of the glass plate, and an electrically conductive layer that contains silver and that is formed on the surface of the ceramic color layer. The ceramic color layer is a firing layer that contains a glass frit and a pigment. The glass frit contains Bi. A lead-free solder layer is formed in at least a partial region on the surface of the electrically conductive layer containing silver. The Bi / Ag mass ratio in the outermost surface of the electrically conductive layer containing silver is less than 0.10.

Description

[Technical Field]

[0001] The present invention relates to vehicle glass. [Background technology]

[0002] 2. Description of the Related Art Glass for vehicles such as automobiles may have a ceramic color layer, which is a colored opaque layer, or a conductive layer formed on the peripheral edge of the glass plate. By forming a ceramic color layer around the periphery of the glass plate, it is possible to protect the urethane sealant that bonds and holds the glass plate to the body of the automobile from deterioration due to ultraviolet rays, and to make conductive layers such as antennas and heating wires formed around the periphery of the glass plate, and mounted components such as mirror bases and brackets adhered to the glass plate, invisible from outside the vehicle.

[0003] The conductive layer is formed for the purpose of forming an antenna, circuit wiring, heating wire, power supply wiring, etc. The conductive layer must have low resistance, and is generally a conductive layer containing silver.

[0004] When forming a silver-containing conductive layer on the surface of the ceramic color layer, one method involves overprinting a paste-like ceramic color composition that will become the ceramic color layer and a silver-containing conductive paste, followed by baking. However, during baking, the silver in the silver-containing conductive paste is prone to pass through the ceramic color layer, a phenomenon known as migration. When the silver migrates to the surface of the glass plate and becomes silver colloid, a phenomenon of color development such as brown is observed. The color development by silver colloid not only impairs the hiding effect intended by the ceramic color layer, but also highlights the presence of the conductive layer and mounted components, detracting from the aesthetic appearance.

[0005] In response to this, Patent Document 1 discloses that by simultaneously blending specific amounts of BaO and MgO in Bi2O3-SiO2-B2O3-based lead-free glass, the melting point of the glass can be lowered without containing alkali oxides. By blending powder of glass with a lower melting point as a glass component in a ceramic color composition, silver migration can be suppressed.

[0006] Meanwhile, with growing concern about the environment worldwide, and in response to the ELV (End-of-Life Vehicles) Directive and other directives, the solder used to connect conductive wires and metal terminals to conductive layers is being replaced by lead-free solder. Lead-free solder is solder with a lead content of 0.1% by mass or less. With the use of lead-free solder, some properties that were previously met without problems when using conventional leaded solder are no longer met, such as glass strength, moisture resistance, peel strength due to deterioration of solder wettability, and heat cycle properties.

[0007] When using leaded solder, a known method is to first apply a thin layer of low-melting-point solder to the surface of the conductive layer with a soldering iron or similar to ensure the connection strength of the terminals. This method maintains high peel strength of the terminals regardless of the solder wettability of the conductive layer surface.

[0008] However, low melting point solders are limited to lead-containing solders, and it is difficult to lower the melting point of lead-free solders due to their composition. Furthermore, lead-free solder has inferior solder wettability compared to leaded solder. This is thought to be due to the following reasons: (i) its high melting point reduces solder wettability at the same operating temperature as conventional solders, (ii) eutectic systems other than bismuth (Bi), which are added in place of lead, have higher surface tension than Sn-Pb eutectic, (iii) Bi and indium (In), which are added in place of lead, are difficult to reduce and remove, reducing solder wettability, and (iv) the high electrode potential, which is close to the potential of the joining base material, makes it difficult for contact corrosion to occur, making it difficult to dissolve and remove the oxide film on the surface of lead-free solder. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2008-266056 Summary of the Invention [Problem to be solved by the invention]

[0010] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a glass for a vehicle that has excellent solder wettability, particularly excellent solder wettability with lead-free solder. [Means for solving the problem]

[0011] As a result of intensive research by the present inventors, it was found that in a conventional vehicle glass having a ceramic color layer and a silver-containing conductive layer on the surface of a glass plate, the higher the firing temperature range, the more likely it is that not only the silver-containing conductive layer will migrate into the ceramic color layer, but also the glass frit constituting the ceramic color layer will migrate into the conductive layer.

[0012] When the glass phase in the glass frit migrates to the outermost surface of the silver-containing conductive layer, the solder wettability of the conductive layer surface is impaired. When solder wettability is impaired and adhesion is poor, stress concentration can easily cause glass cracking and peeling of the ceramic color layer when lead-free solder is used. Weather resistance, i.e., peeling of the ceramic color layer and glass cracking after humidity resistance and heat cycle tests, also become issues. This is due to the fact that lead-free solder is harder than leaded solder.

[0013] If the migration of the glass frit constituting the ceramic color layer to the conductive layer can be suppressed, the resulting decrease in solder wettability can be suppressed, and excellent solder wettability can be achieved for vehicle glass. In other words, the above problem can be solved by reducing the amount of components derived from the glass frit on the outermost surface of the silver-containing conductive layer.

[0014] Based on the above, the present invention relates to the following [1] to

[15] . [1] A vehicle glass comprising a glass plate, a ceramic color layer formed on a surface of the glass plate, and a silver-containing conductive layer formed on the surface of the ceramic color layer, wherein the ceramic color layer is a fired layer containing glass frit and a pigment, the glass frit contains Bi, a lead-free solder layer is formed in at least a partial region on the surface of the silver-containing conductive layer, and the mass ratio of Bi / Ag on the outermost surface of the silver-containing conductive layer is less than 0.10. [2] The vehicle glass according to [1], wherein the migration amount expressed as the product of the mass concentration of O (oxygen) at the outermost surface of the silver-containing conductive layer and the thickness of the silver-containing conductive layer is 75% μm or less. [3] The vehicle glass according to [1] or [2], wherein the silver-containing conductive layer includes a crystallized region derived from the glass frit. [4] The vehicle glass according to any one of the above [1] to [3], wherein the mass ratio of SiO2 / Bi2O3 in the ceramic color layer is 0.3 to 1.0. [5] The vehicle glass according to any one of the above [1] to [4], wherein the ceramic color layer further contains a filler. [6] The vehicle glass according to [5], wherein the filler contains at least one selected from the group consisting of cordierite, zircon, and silica. [7] The vehicle glass according to any one of [1] to [6], wherein the thickness of the ceramic color layer is less than 15 μm, and the contents of Na2O, K2O and Bi2O3 on the outermost surface of the ceramic color layer after a humidity resistance test under conditions of 80°C and a humidity of 96% RH for 500 hours satisfy the relationship {(Na2O + K2O) / Bi2O3}<0.20. [8] The thermal expansion coefficient of the ceramic color layer at 50 to 350 ° C. is 60 × 10 -7 ~77×10 -7 / °C. The vehicle glass according to any one of the above [1] to [7]. [9] The vehicle glass according to any one of the above [1] to [8], wherein the softening point Ts of the glass frit is 500 to 580°C.

[10] The vehicle glass according to any one of the above [1] to [9], wherein the 0.1% breakage strength in a Weibull plot of static load strength is 20 MPa or more.

[11] The vehicle glass according to

[10] , wherein a terminal is joined via the lead-free solder layer, and after a humidity resistance test in which the terminal is subjected to an elapsed time of 500 hours under conditions of 80°C and a humidity of 96% RH, the peel strength of the terminal is 100 N or more.

[12] The vehicle glass according to any one of the above [1] to

[11] , wherein the lead-free solder layer contains 95 mass % or more of Sn.

[13] The vehicle glass according to any one of the above [1] to

[12] , wherein the lead-free solder layer is formed via a halogen-free flux.

[14] The vehicle glass according to any one of [1] to

[13] , wherein the ceramic color layer contains, in mass % on an oxide basis, 15 to 30% SiO2, 30 to 55% Bi2O3, 0 to 4% B2O3, 1 to 4% Al2O3, 0 to 3% Li2O, 0 to 1.8% Na2O+K2O, 1 to 10% MgO+CaO+BaO+SrO, 0 to 10% ZnO, 0 to 5% TiO2, 0 to 1% CeO2, 0 to 2% ZrO2, and 10 to 20% CuO+CrO+MnO+NiO+CoO, and the contents of the respective components satisfy the relationships of Na2O+K2O+B2O3: 0.1 to 4.0%, B2O3 / Bi2O3: 0 to 0.08, and SiO2 / Bi2O3: 0.3 to 1.0.

[15] The vehicle glass according to any one of the above [1] to

[14] , which is used as a laminated glass for a windshield. [Effects of the Invention]

[0015] According to the present invention, a vehicle glass having a ceramic color layer and a conductive layer and excellent solder wettability can be realized. Therefore, terminals can be bonded with high strength via a lead-free solder layer without the need for a thin coating of low-melting-point solder containing lead. This prevents the glass phase (amorphous phase) in the glass frit from floating from the ceramic color layer to the conductive layer surface, even when lead-free solder is used, and also prevents cracking of the glass due to stress concentration and peeling of the ceramic color layer. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a vehicle glass according to this embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view showing an example of a vehicle glass according to this embodiment. [Figure 3] FIG. 3 is a graph showing the Bi / Ag mass ratio in the outermost surface of the conductive layer of the vehicle glass according to Examples 6, 8, and 9 in the firing temperature range of 590 to 650°C. [Figure 4] FIG. 4 is a scanning electron microscope (SEM) image of a cross section of the conductive layer and the ceramic color layer of the vehicle glass according to Example 5. [Figure 5] FIG. 5 is an SEM image of a cross section of the conductive layer and the ceramic color layer of the vehicle glass according to Example 8. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be modified as desired without departing from the spirit of the present invention. Furthermore, the symbol "to" indicating a numerical range is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0018] <Vehicle glass> As shown in Fig. 1, the vehicle glass 10 according to this embodiment has a ceramic color layer 2 formed on the surface of a glass plate 1, and a silver-containing conductive layer 3 formed on the ceramic color layer 2. As shown in Fig. 2, a lead-free solder layer 4 is preferably formed on at least a partial region of the surface of the silver-containing conductive layer 3. The ceramic color layer 2 is a fired layer containing glass frit and pigment, and the glass frit contains bismuth (Bi).

[0019] The ceramic color layer may be formed on at least a portion of the surface of the glass plate. A paste-like ceramic color composition that serves as a precursor of the ceramic color layer is applied to a desired area of ​​the surface of the glass plate and then baked to form a fired layer. In this specification, the ceramic color layer refers to a fired product of the ceramic color composition, and the ceramic color composition is an inorganic component that includes glass frit and pigment. When this ceramic color composition is applied to the surface of the glass plate, a mixture of the ceramic color composition with an organic component to form a paste is referred to as a paste-like ceramic color composition.

[0020] By forming the ceramic color layer as a fired layer, the ceramic color layer is bonded to the glass plate, and as a result, even if a silver-containing conductive layer (hereinafter sometimes simply referred to as a "conductive layer"), a solder layer, or the like is further formed on the surface of the ceramic color layer, peeling of the ceramic color layer from the glass plate can be prevented. Furthermore, when the ceramic color layer is fired, a curved surface may be formed on the glass plate by a bending process using heat, which is called firing bending.

[0021] The silver-containing conductive layer may be formed on at least a portion of the surface of the ceramic color layer. A film of a silver-containing conductive paste is formed on a desired area of ​​the surface of the ceramic color layer by coating or the like, and then heated and dried. Alternatively, a film of a silver-containing conductive paste may be formed on a film of the ceramic color composition, and the conductive layer may be formed at the same time as firing to form the ceramic color layer. Furthermore, when forming the conductive layer, a curved surface may be formed on the glass plate by firing bending.

[0022] The glass plate of the vehicle glass according to this embodiment often has a curved surface due to its intended use, and may be subjected to the aforementioned firing bending when the ceramic color layer and the conductive layer are formed. Alternatively, firing bending may be performed after the ceramic color layer and the conductive layer are formed. Alternatively, firing bending may be performed after the ceramic color layer and the conductive layer are formed, and then calcination may be performed once.

[0023] If the heating temperature during the formation of the ceramic color layer or the conductive layer, the calcination, or the firing bending exceeds the softening point of the glass frit, the glass frit constituting the ceramic color layer migrates, i.e., diffuses, causing the glass phase in the glass frit to rise to the surface of the conductive layer and remain on the surface. This lifting of the glass phase in the glass frit reduces the solder wettability of the conductive layer surface. Generally, the higher the heating temperature, the greater the amount of migration. The heating temperature varies depending on the desired radius of curvature of the glass plate, and there is also a temperature distribution within a single glass plate. Therefore, it is necessary to control the amount of glass frit migration into the conductive layer over a wide desired temperature range.

[0024] When leaded solder is used, the low-melting-point leaded solder is thinly applied to the surface of the conductive layer with a soldering iron or the like before the leaded solder is bonded, so it is less susceptible to migration. On the other hand, when lead-free solder is used, it is susceptible to the effects of migration because the low-melting point lead-free solder cannot be applied to the surface of the conductive layer. Also, if the ceramic color layer used with leaded solder is applied to lead-free solder as is, migration will occur in the temperature range of 550-600°C and above, causing the glass phase in the glass frit to rise to the surface of the conductive layer, reducing solder wettability, making it difficult to apply lead-free solder.

[0025] Therefore, in order to obtain good solder wettability in the vehicle glass having the ceramic color layer and the conductive layer according to this embodiment, the mass ratio of Bi / Ag on the outermost surface of the conductive layer is less than 0.10, more preferably less than 0.09, even more preferably 0.05 or less, and even more preferably 0.04 or less. The mass ratio of Bi / Ag can be determined by quantifying the detected elements including Bi in mass% from the outermost surface side of the conductive layer using SEM-EDX (energy dispersive X-ray spectroscopy) or XPS (X-ray photoelectron spectroscopy) and normalizing it with Ag.

[0026] The firing temperature in the manufacturing process of vehicle glass is generally 500°C to 700°C. To achieve the desired color within this temperature range, the glass frit must be made to flow from a low temperature range. To achieve this, the Bi content is generally increased. However, the higher the firing temperature, the more likely the glass phase (amorphous phase) in the glass frit migrates to the conductive layer, and the Bi / Ag mass ratio at the outermost surface of the conductive layer tends to increase. However, we have newly discovered that crystallization of the glass frit in the ceramic color layer reduces the glass phase itself in the glass frit, suppressing its migration to the conductive layer, thereby reducing the Bi / Ag mass ratio at the outermost surface of the conductive layer. We have also newly discovered that crystallization of the glass phase that has migrated into the conductive layer can also suppress the migration of the glass phase to the outermost surface of the conductive layer. In other words, by increasing the crystallized region derived from the glass frit in the ceramic color layer, or by including a crystallized region derived from the glass frit in the conductive layer, migration of the glass frit to the outermost surface of the conductive layer can be effectively suppressed. As a result, the Bi / Ag mass ratio on the outermost surface of the conductive layer can be lowered compared to conventional methods, achieving good solder wettability with lead-free solder. We also newly discovered that controlling the SiO2 / Bi2O3 ratio in the ceramic color layer is also important in achieving the above-mentioned crystallized region in the ceramic color layer and conductive layer.

[0027] Since the firing temperature and firing bending temperature of the ceramic color layer are usually about 500 to 700°C, if the Bi / Ag mass ratio of a vehicle glass that has undergone a firing process at a temperature of at least 500°C or higher is less than 0.10, it can be said that the solder wettability is good, and is preferably less than 0.09, more preferably 0.05 or less, and even more preferably 0.04 or less. Furthermore, the Bi / Ag mass ratio of a vehicle glass that has undergone a firing process at a temperature of 590°C or higher is preferably less than 0.10, more preferably less than 0.09, even more preferably 0.05 or less, and even more preferably 0.04 or less. Furthermore, the Bi / Ag mass ratio of a vehicle glass that has undergone a firing process at a temperature of 630°C or higher is preferably less than 0.10, more preferably less than 0.09, even more preferably 0.05 or less, and even more preferably 0.04 or less. Furthermore, the average value of the Bi / Ag mass ratio of the vehicle glass that has undergone the firing process over the entire temperature range of 590 to 650° C. is preferably less than 0.10, more preferably less than 0.09, even more preferably 0.05 or less, and even more preferably 0.04 or less. Furthermore, the maximum value of the Bi / Ag mass ratio of the vehicle glass that has undergone the firing process over the entire temperature range of 590 to 650° C. is preferably less than 0.10, more preferably less than 0.09, even more preferably 0.05 or less, and even more preferably 0.04 or less.

[0028] The concentration of glass frit that migrates into the conductive layer, typically the Bi concentration, has a gradient. Specifically, in the conductive layer, the closer to the ceramic color layer the Bi content is. Also, in the conductive layer, the Bi content gradually decreases as you approach the surface. However, Bi that migrates to the outermost surface has nowhere to go and remains there. Therefore, the Bi / Ag mass ratio at a certain depth from the outermost surface of the conductive layer may be smaller than the Bi / Ag mass ratio at the outermost surface of the conductive layer. Therefore, when the layer where Bi remains is referred to as the outermost layer, the thickness of the outermost layer in the depth direction from the outermost surface of the conductive layer is preferably 0 to 2 μm, more preferably 0 to 1.5 μm, even more preferably 0 to 1 μm, and even more preferably 0 to 0.5 μm. The thinner the outermost layer, the less Bi remains, and it can be determined that the amount of Bi that migrates to the conductive layer is smaller.

[0029] The migration can be quantified as the amount of migration by the value expressed as the product of the mass concentration of O (oxygen) at the outermost surface of the silver-containing conductive layer and the thickness of the silver-containing conductive layer {(mass concentration of O) × (thickness of the silver-containing conductive layer)}. The migration amount expressed by the above product is preferably 75% μm or less, more preferably 70% μm or less, and even more preferably 60% μm or less, from the viewpoint of obtaining good solder wettability. Furthermore, the migration amount is preferably 25% μm or more, more preferably 40% μm or more, and even more preferably 50% μm or more, from the viewpoint of increasing the bonding strength at the interface between the ceramic color layer and the conductive layer. As mentioned above, if Bi is present on the outermost surface of the conductive layer, the migration amount expressed by the above product will be overestimated compared to when Bi is not present, resulting in a higher migration amount than the actual migration amount. However, since the presence of Bi on the outermost surface means that a large amount of migration occurs in the first place, it is preferable that the migration amount expressed by the above product be 75% μm or less, regardless of whether Bi is present or not. The migration amount is the value when the vehicle glass is heated at 630°C. However, although the migration amount of vehicle glass varies depending on the heating temperature, the difference is not so large. Therefore, for example, if the migration amount when heated at 630±30°C is within ±2% of the above range, it can be assumed that the migration amount when heated at 630°C will also be within the above range. The mass concentration (mass %) of oxygen at the outermost surface of the conductive layer is determined from the outermost surface side of the conductive layer using SEM-EDX (energy dispersive X-ray spectroscopy) or the like. The thickness of the conductive layer can be measured using a cross-sectional SEM. It is also possible to use a value obtained by measuring the step height using an integrated contour measuring instrument in the area where the conductive layer is formed, between the area where the conductive layer is formed and the area where the conductive layer is not formed, i.e., the area where only the ceramic color layer is formed.

[0030] The Bi / Ag mass ratio on the outermost surface of the conductive layer can be controlled by the composition and crystallinity of the ceramic color composition, which is the precursor of the ceramic color layer, firing conditions, etc. Increasing the crystallized region in the ceramic color layer, i.e., increasing the crystallinity, reduces the glass phase in the ceramic color layer, and as a result, the amount of glass phase in the glass frit that migrates into the conductive layer can be reduced. In addition, by crystallizing the glass phase itself that has migrated into the conductive layer and forming a crystallized region, it is possible to prevent the glass phase, which is a component containing Bi in the glass frit, from floating up to the outermost surface of the conductive layer. The crystallized region in the ceramic color layer and the conductive layer can be controlled, for example, by the SiO2 / Bi2O3 ratio of the ceramic color layer. As a result, the mass ratio of Bi / Ag on the outermost surface of the conductive layer can be reduced.

[0031] For the above reasons, it is preferable that the ceramic color layer contains many crystallized regions derived from the glass frit, and it is also preferable that the conductive layer contains crystallized regions derived from the glass frit. The crystallized region derived from the glass frit in the ceramic color layer is a region where the glass frit in the ceramic color composition has become a crystalline phase. The crystallized region derived from the glass frit in the conductive layer is a region where the glass phase in the glass frit that has migrated from the ceramic color layer or its precursor, the ceramic color composition, into the conductive layer has become a crystalline phase. The presence of the crystallized region eliminates the glass phase on the outermost surface of the conductive layer, or, if present, significantly reduces its amount, thereby reducing the Bi / Ag mass ratio on the outermost surface of the conductive layer.

[0032] The glass frit crystallizes when it is heated at a temperature higher than the crystallization temperature during firing to form the ceramic color layer or the conductive layer, or when the glass is fired and bent. That is, the glass phase in the glass frit that has migrated into the conductive layer can also be crystallized by the heat treatment depending on the composition.

[0033] From the above viewpoints, it is preferable to add a crystallization accelerator to the ceramic color composition. The presence of the crystallization accelerator facilitates the formation of a crystalline phase derived from the glass frit. In other words, the crystallization accelerator acts as a nucleus, so that crystallization begins in a temperature range lower than the temperature at which glass frit normally begins to crystallize, making it easier for the glass phase of the glass frit to crystallize. Furthermore, crystallization tends to occur more uniformly within the ceramic color layer. These actions reduce the absolute amount of glass phase that migrates into the conductive layer. As a result, the glass phase in the glass frit can be prevented from migrating to the outermost surface of the conductive layer.

[0034] The crystallization accelerator varies depending on the composition of the glass frit. However, since the glass frit contains Bi, a bismuth silicate-based crystallization accelerator is preferred, such as Bi4Si3O 12 , Bi 12 SiO 20 Furthermore, when the crystalline phases have a similar pattern, crystallization may be promoted even if the compositions are different. For example, when the content of each component on an oxide basis in the ceramic color layer satisfies the relationship SiO2 / Bi2O3≧0.3, low expansion Bi4Si3O 12 The crystals precipitate, reducing the expansion of the ceramic color layer. Therefore, the same crystallization promoter Bi4Si3O as the precipitated crystals is used. 12 However, it is preferable to add Bi, which has a different crystal system. 12 SiO 20 Even in the ceramic color layer, when the temperature reaches 500°C or higher, Bi4Si3O 12 To transform into a crystal, Bi 12 SiO 20 However, since the crystallization accelerator has a large effect even when added in small amounts, if the crystallization accelerator has the same crystal system as the crystal to be precipitated, it is recommended to use Bi4SiO 12 is more preferred.

[0035] The glass phase in the glass frit that has migrated into the ceramic color layer or conductive layer preferably exists as a crystallized region, and it is more preferable that the amount of precipitation is large, i.e., the degree of crystallization is high. The presence of a crystallized region can be confirmed as rod-shaped crystals, needle-shaped crystals, granular crystals, etc. in a cross-sectional SEM photograph. Furthermore, when measured by X-ray diffraction (XRD) or grazing incidence X-ray diffraction measurement, it is preferable that the diffraction peak of bismuth silicate crystals derived from the glass frit is detected. In this case, Bi4Si3O is used as a crystallization promoter. 12 Since the crystallization promoter and the like are added, diffraction peaks of bismuth silicate crystals may be detected at a very low intensity. However, when the components in the glass frit crystallize, the intensity becomes much higher than the intensity of the added crystallization promoter alone, making it possible to fully distinguish between the components added as a crystallization promoter and those resulting from precipitation. Specifically, a crystallization degree that is several tens of times or more stronger than the intensity of the crystallization promoter alone is preferred, and a crystallization degree that is several hundred times or more stronger is more preferred.

[0036] In XRD and grazing incidence X-ray diffraction measurements, the diffraction lines from the crystalline phase appear as peaks, and the scattered light from the amorphous phase appears as a halo. The degree of crystallinity can be calculated by fitting this halo to the crystalline peak, analyzing the intensities, and using the following formula: Crystallinity X=I c / (I c +I a ) x 100 (I c :Crystalline scattering integrated intensity, I a :Amorphous scattering integrated intensity)

[0037] In this embodiment, the crystallinity X derived from the glass frit in the ceramic color layer and the conductive layer is preferably 10% or more, more preferably 20% or more, even more preferably 30% or more, and even more preferably 40% or more. On the other hand, if the crystallinity is too high, the amount of glass component in the amorphous phase becomes too small, which may make it difficult to achieve the characteristics required for vehicle glass, such as color tone. Therefore, the crystallinity X is preferably 70% or less, more preferably 60% or less, and even more preferably 50% or less. The crystallinity in the ceramic color layer and the crystallinity in the conductive layer may be the same or different.

[0038] The softening point Ts of the glass frit is also related to the temperature at which the glass is fired and bent. From the viewpoint of good firing, the softening point Ts of the glass frit is preferably 500°C or higher, more preferably 520°C or higher. On the other hand, the higher the firing and bending temperature, the more active the glass frit is in migrating into the conductive layer. From the viewpoint of reducing the amount of migration, the softening point Ts of the glass frit is preferably 580°C or lower, more preferably 540°C or lower. The softening point Ts of the glass frit can be controlled by the composition of the glass frit. In this specification, the softening point Ts is the temperature at the fourth inflection point in a DTA chart obtained by differential thermal analysis (DTA) of the glass frit. Although it is difficult to directly measure the softening point Ts of the glass frit from the vehicle glass after firing, the softening point Ts can be estimated by inferring the composition of the glass frit from the composition of the ceramic color layer, and then performing a regression calculation using the composition of the glass frit.

[0039] Glass frit particle size D 50 The particle size of the glass frit D is also related to the temperature at which the glass is fired and bent. 50 The smaller the particle size of the glass frit, the more the glass flows at low temperatures and the easier it is to achieve the desired color tone, but the amount of migration to the conductive layer also tends to increase. On the other hand, if the particle size of the glass frit is large, the flow of the glass shifts to the high temperature side, making it difficult to achieve the desired color tone, but it contributes to suppressing the amount of migration to the conductive layer. In addition, the particle size of the glass frit D 50 Even when the crystallinity is small, the amount of migration into the conductive layer can be adjusted while maintaining the desired color tone by increasing the crystallinity. Furthermore, by making the particle size distribution curve show two maxima, i.e., a bimodal curve, the amount of migration into the conductive layer can be adjusted while maintaining the desired color tone. The particle size distribution curve may also show three or more maxima, i.e., a trimodal or higher curve.

[0040] Specifically, the particle diameter D of the glass frit 50However, when the volume-based particle size distribution curve measured by a laser diffraction scattering method is bimodal, the first peak of the bimodal curve is preferably between 0.1 and 1.0 μm, more preferably between 0.3 and 1.0 μm, even more preferably between 0.3 and 0.9 μm, even more preferably between 0.3 and 0.8 μm, and particularly preferably between 0.5 and 0.8 μm. The second peak of the bimodal curve is preferably between 1.0 and 3.0 μm, more preferably between 1.0 and 2.5 μm, and even more preferably between 1.0 and 2.0 μm.

[0041] Conventional pigments can be used in the ceramic color layer. For example, combinations of CuO·Cr2O3 (black), CoO·Cr2O3 (black), Fe2O3 (brown), TiO2 (white), CoO·Al2O3 (blue), and NiO·Cr2O3 (green) can be used. The use of such pigments can impart the desired color, gloss, and opacity, i.e., transmittance, characteristics. Among these, it is preferable to use a black pigment to form a black ceramic layer for the purpose of providing a ceramic color layer.

[0042] When forming a black ceramic layer, the pigment is preferably at least one oxide pigment selected from the group consisting of Cu, Fe, Co, Ni, Cr, Si, Mn, Al, and Zn, more preferably a composite oxide pigment containing two or more of these, and even more preferably at least one composite oxide pigment selected from the group consisting of Cu(Cr,Mn)2O4, CuCrO4, Cr2O3:Fe2O3, Cr2O3:Fe2O3:CoO, (Fe,Mn)(Mn,Fe)2O4, (Co,Fe)(Fe,Cr)2O4, (Co,Fe,Mn)(Fe,Cr,Mn)2O4, (Co,Fe)(Ni,Cr)2O4, and (Cu,Fe,Mn)(Fe,Mn,Al)2O4.

[0043] When the ceramic color layer is a black ceramic layer, its color quality can be expressed by its lightness index L* value in the CIE 1976 (L*a*b*) color space (CIELAB) standardized by the International Commission on Illumination (CIE). The lightness index L* value indicates the brightness of the color tone and can be measured in accordance with JIS Z 8722 (2009). A higher L* value indicates a brighter color tone, while a lower L* value indicates a darker color tone. When the L* value of the black ceramic layer is in the range of 0 to 30, the color is black, achieving its intended purpose as vehicle glass. Furthermore, from the viewpoint of further enhancing the sense of luxury and aesthetic satisfaction, taking into account the blackness of the L* value, an L* value of 18 or more is preferred, more preferably 20 or more, and even more preferably 21 or more. On the other hand, an L* value exceeding 30 results in an increased whiteness, so an L* value of 30 or less is preferred, more preferably 25 or less, and even more preferably 23 or less.

[0044] The ceramic color layer preferably contains a filler in addition to the glass frit and the pigment, and the above-mentioned crystallization accelerator is contained in the filler. As the filler other than the crystallization accelerator, a so-called low-expansion filler is preferred from the viewpoint of improving the strength of the vehicle glass, because glass frit and pigments generally have a higher thermal expansion coefficient than the glass plate.

[0045] When providing a solder layer on vehicle glass, in addition to thermal stress caused by localized heating of the glass sheet during soldering and residual stress after cooling, stress caused by the difference in thermal expansion coefficient between the glass sheet and the solder can occur, which can reduce the strength of the vehicle glass. In response to this, by incorporating a low-expansion filler into the ceramic color layer interposed between the glass sheet and the solder layer, the expansion of the ceramic color layer caused by localized heating of the glass sheet during soldering can be suppressed. This reduces the stress caused by the difference in thermal expansion coefficient between the glass sheet and the solder, and prevents a decrease in the strength of the vehicle glass.

[0046] In terms of the thickness of the ceramic color layer, the particle diameter D of the low expansion filler 50On the other hand, from the viewpoint of preventing excessive particle size reduction that would result in poor sinterability, the particle size D 50 is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 4 μm or more.

[0047] The low-expansion filler may have a bimodal or trimodal distribution, which shows two or more peaks, in a volumetric particle size distribution curve measured by a laser diffraction scattering method, or a unimodal distribution, which shows one peak. However, as mentioned above, a large amount of fine particles reduces sinterability, so if sinterability is important, a unimodal distribution without fine particles is preferred. If the distribution is unimodal, it is more preferable that the maximum peak is between 4 and 8 μm. In order to achieve a unimodal particle size distribution, optimization of the grinding conditions or classification may be performed.

[0048] The low-expansion filler preferably has a spherical or crushed shape. Because the spherical shape has a small specific surface area per unit volume, it has excellent fluidity and high sinterability when the ceramic color layer is fired. Therefore, a relatively large amount of low-expansion filler can be contained in the ceramic color layer. On the other hand, crushed fillers are preferred because they can be mass-produced at low cost and are easily available, although their sinterability is slightly inferior to that of spherical fillers.

[0049] Examples of low expansion fillers include cordierite, zircon, alumina, titania, zirconium phosphate, silica, and forsterite. One of these may be used alone, or two or more may be mixed together. Among these, it is more preferable to use at least one selected from the group consisting of cordierite, zircon, and silica. Cordierite, zircon, and silica may be in a pulverized form, but spherical form is more preferable, and in the case of silica, spherical silica is more preferable.

[0050] Silica can be either crystalline or amorphous (non-crystalline). Silica surfaces contain silicon (Si-OH) bonded to hydroxyl groups called silanol groups, which are a major factor in the physical properties of water repellency and hydrophilicity. Amorphous silica has a higher amount of silicon (Si-OH) bonded to hydrogen than crystalline silica, which increases the bonding strength when bonding with urethane sealants, etc. For this reason, amorphous silica is more preferable.

[0051] The ceramic color layer may further contain an oxidizing agent within a range that does not impair the effects of the present invention. The oxidizing agent can be a conventionally known one, for example, CeO2, MnO2, etc. The average particle diameter D of the oxidizing agent 50 From the viewpoint of productivity, the average particle diameter D of the oxidizing agent is preferably 0.1 μm or more, and from the viewpoint of sinterability, the average particle diameter D is more preferably 1 μm or more, and even more preferably 3 μm or more. 50 is preferably 15 μm or less, more preferably 10 μm or less.

[0052] The thermal expansion coefficient of the ceramic color layer needs to be equal to or less than that of the glass plate, but is preferably close to that of the glass plate from the viewpoint of obtaining high strength as a vehicle glass. By making the thermal expansion coefficient close to that of the glass plate, even if residual stress occurs in the glass plate when a solder layer is provided on the vehicle glass, expansion of the ceramic color layer and the conductive layer can be suppressed, and a decrease in the strength of the vehicle glass can be suppressed.

[0053] Therefore, the thermal expansion coefficient of soda lime glass is 85 x 10 -7 ~90×10 -7 / °C, for example, the thermal expansion coefficient of the ceramic color layer at 50 to 350°C is 40 × 10 -7 / ℃ or more is preferable, and 50×10 -7 / ℃ or more is more preferable, and 60×10 -7 / °C or more. The thermal expansion coefficient of the ceramic color layer at 50 to 350°C is more preferably 85×10 -7 / ℃ or less is preferable, and 80 × 10 -7 / ℃ or less is more preferable, and 77×10 -7 / °C or less is more preferable. Since it is difficult to directly measure the thermal expansion coefficient of the ceramic color layer, the thermal expansion coefficient in this specification is a value measured using a differential thermal dilatometer as the average value of the rate of elongation per 1°C when the ceramic color composition is heated in the range of 50 to 350°C.

[0054] The ceramic color layer will be distorted if there is a difference in the thermal expansion coefficient between the ceramic color layer and the glass plate. The distortion of the glass plate can be measured using polarized light, and the residual stress applied to the glass plate can be calculated from this measurement. Specifically, the magnitude of birefringence is measured, and the residual stress is calculated using the separately determined photoelastic constant of the glass plate. Commercially available birefringence measurement devices are available from Luceo Co., Ltd., Orihara Manufacturing Co., Ltd., and HINDS Instruments Inc. (USA), and employ methods such as the crossed Nicols method, circular polarization method, sensitive color method, Senarmont method, and rotating analyzer method. It is important to note that these residual stress measurement devices can only measure the stress in the transparent glass plate, and cannot measure the stress in the ceramic color layer. The ceramic color layer must be considered assuming a residual stress that balances the stress in the glass plate.

[0055] Soda-lime glass, a typical glass used in vehicles, has a composition expressed in mass percent oxides: silica (SiO2): 70-73 mass%, alumina (Al2O3): 0.6-2.4 mass%, iron oxide (Fe2O3): 0.08-0.14 mass%, lime (CaO): 7-12 mass%, magnesia (MgO): 1.0-4.5 mass%, and alkali metals (R2O: Na2O + K2O): 13-15 mass%. Because of the high R2O content, trace amounts of Na (sodium ions) and K (potassium ions) are known to dissolve in water at the interface between the glass and water. The dissolved Na and K react with carbon dioxide in the air to form salts such as sodium carbonate and potassium carbonate. This is the typical water-induced corrosion of the glass surface, known as glass burn. Furthermore, the reacted sodium and potassium carbonates themselves are also easily redissolved in water.

[0056] In the moisture resistance test of the ceramic color layer, as with the glass plate, a reaction between the ceramic color layer and moisture may occur. In other words, if the ceramic color layer contains a large amount of sodium or potassium components that are easily soluble in water, glass burning may occur on the surface of the ceramic color layer. However, although it belongs to the same alkali metal group, lithium salts such as lithium carbonate have low solubility in water, so glass burning is unlikely to occur even when the sodium and potassium component contents are the same.

[0057] The peel strength at the interface between the ceramic color layer and the conductive layer is correlated with the bonding strength at the interface between the ceramic color layer and the conductive layer. Furthermore, during a humidity resistance test, the bonding strength may be reduced by water, so in order to maintain a high peel strength, it is necessary to prevent the reduction in bonding strength. From the perspective of increasing the bonding strength at the interface between the ceramic color layer and the conductive layer, it is advantageous to increase the amount of migration from the ceramic color layer to the conductive layer. However, increasing the amount of migration also deteriorates solder wettability. On the other hand, to improve solder wettability, it is necessary to suppress migration from the ceramic color layer to the conductive layer. To achieve this, it is preferable to increase the crystallinity of the ceramic color layer. However, if the crystallinity is increased too much, migration from the ceramic color layer to the conductive layer is suppressed, but as mentioned above, the bonding (adhesion) strength between the ceramic color layer and the conductive layer weakens. As such, there is a trade-off between the two, so it is important to allow an appropriate amount of migration from the ceramic color layer to the conductive layer.

[0058] The peel strength after the moisture resistance test is also affected by the amount of hydrophilic components at the interface between the ceramic color layer and the conductive layer. In other words, moisture during the moisture resistance test penetrates between the interface between the ceramic color layer and the conductive layer, dissolving the hydrophilic components, creating voids between the ceramic color layer and the conductive layer, resulting in a decrease in tensile strength during the peel test. Therefore, it is important to control the composition of the interface between the ceramic color layer and the conductive layer, particularly the hydrophilic components.

[0059] It is difficult to directly measure the amount of hydrophilic components at the interface between the ceramic color layer and the conductive layer. However, in the region of the ceramic color layer extending from the edge of the conductive layer to a distance of several hundred micrometers where the conductive layer is not formed, migration spreads in both directions, so the composition can be considered to be equivalent to the composition at the outermost surface of the ceramic color layer where the conductive layer is not formed. Therefore, the concentration of hydrophilic components at the interface between the ceramic color layer and the conductive layer can be determined by analyzing the composition at the outermost surface of the ceramic color layer in a region within a few hundred micrometers from the edge of the conductive layer. Although the ceramic color composition before firing, the ceramic color layer after firing, and the outermost surface of the ceramic color layer after the moisture resistance test may have the same composition, the outermost surface composition may change due to phase separation between the crystalline phase and the glass phase caused by crystallization, or because alkali metals and the like may move or dissolve within the ceramic color layer.

[0060] Na2O and K2O are hydrophilic components, but B2O3 is also a hydrophilic component. From the viewpoint of obtaining good peel strength after a moisture resistance test, it is preferable to keep the total content expressed as (Na2O + K2O + B2O3) in the ceramic color composition low. On the other hand, since it is difficult to quantify boron (B) by surface analysis, the amount of B2O3 / Bi2O3 in the ceramic color composition, i.e., the total composition including glass frit, filler, and pigment, is controlled. Specifically, the value of B2O3 / Bi2O3 in the composition of the ceramic color composition is preferably 0.08 or less.

[0061] On the other hand, the contents of Na2O, K2O, and Bi2O3 at the outermost surface of the ceramic color layer are determined by SEM-EDX analysis or XPS of the surface portion of the ceramic color layer. Therefore, the Na2O, K2O, and Bi2O3 analytical values ​​are used for the determination. Specifically, the value of {(Na2O + K2O) / Bi2O3}, which is expressed as the contents of Na2O, K2O, and Bi2O3 at the outermost surface of the ceramic color layer after the moisture resistance test, is preferably less than 0.20, more preferably 0.10 or less, and the smaller the better. The moisture resistance test is conducted under conditions of 80°C and 96% RH for 500 hours. In SEM-EDX, lowering the acceleration voltage makes it possible to analyze only the layer closer to the surface of the ceramic color layer. Considering the thickness of the ceramic color layer, the acceleration voltage for sufficient excitation is preferably 5 to 15 kV or less, more preferably 5 to 10 kV or less. In this case, the thickness of the ceramic color layer is preferably less than 15 μm.

[0062] The ceramic color layer preferably satisfies, for example, the following composition. The composition of the ceramic color layer in this specification refers to the total composition of the glass frit and pigment, and when the ceramic color layer further contains other inorganic components such as fillers, it refers to the total composition including these inorganic components. The composition of the ceramic color layer may be considered to be the same as the composition of the ceramic color composition before firing. In terms of oxide mass%, SiO2 15~30%, Bi2O3 30~55%, B2O3 0~4%, Al2O3 1-4%, Li2O 0~3%, Na2O+K2O 0~1.8%, MgO+CaO+BaO+SrO 1~10% ZnO 0-10%, TiO20-5%, CeO20~1%, ZrO20~2%, and CuO+CrO+MnO+NiO+CoO 10~20% Contains The content of each ingredient is Na2O+K2O+B2O30.1~4.0% B2O3 / Bi2O3 0~0.08, and SiO2 / Bi2O3 0.3~1.0 Satisfy the relationship.

[0063] The ceramic color layer more preferably satisfies, for example, the following composition. In terms of oxide mass%, SiO2 15~30%, Bi2O3 30~55%, B2O3 0~4%, Al2O3 1-4%, Li2O 0~3%, Na2O+K2O 0~1.8%, MgO+CaO+BaO+SrO 1~10% ZnO 0-10%, TiO20-5%, CeO20~1%, ZrO20~2%, and CuO+CrO+MnO+NiO+CoO 10~20% Contains The content of each ingredient is Na2O+K2O+B2O30.1~3.0% B2O3 / Bi2O3 0~0.08, and SiO2 / Bi2O3 0.3~1.0 Satisfy the relationship.

[0064] It is more preferable that the ceramic color layer satisfies, for example, the following composition. In terms of oxide mass%, SiO2 15~28.6%, Bi2O3 40~55%, B2O3 0~4%, Al2O3 1-4%, Li2O 0~3%, Na2O+K2O 0~1.8%, MgO+CaO+BaO+SrO 1~10% ZnO 0-10%, TiO20-5%, CeO20~1%, ZrO20~2%, and CuO+CrO+MnO+NiO+CoO 10~20% Contains The content of each ingredient is Na2O+K2O+B2O30.1~3.0% B2O3 / Bi2O3 0~0.08, and SiO2 / Bi2O3 0.3~0.65 Satisfy the relationship.

[0065] It is more preferable that the ceramic color layer satisfies, for example, the following composition. In terms of oxide mass%, SiO2 20~28.6%, Bi2O3 49~55%, B2O3 0~3%, Al2O3 1-4%, Li2O 0~3%, Na2O+K2O 0~1.4%, MgO+CaO+BaO+SrO 1~10% ZnO 0-6%, TiO2 0.1-1.5%, CeO20~1%, ZrO20~0.5%, and CuO+CrO+MnO+NiO+CoO 10~15% Contains The content of each ingredient is Na2O+K2O+B2O30.1~3.0% B2O3 / Bi2O3 0~0.07, and SiO2 / Bi2O3 0.35~0.65 Satisfy the relationship.

[0066] It is particularly preferable that the ceramic color layer satisfies, for example, the following composition. In terms of oxide mass%, SiO2 20-25%, Bi2O3 49~55%, B2O3 0~2%, Al2O3 2-4%, Li2O 0~1.5%, Na2O+K2O 0~1% MgO+CaO+BaO+SrO 4~10% ZnO 0-1%, TiO2 0.1-1%, CeO20~1%, ZrO20~0.5%, and CuO+CrO+MnO+NiO+CoO 10~15% Contains The content of each ingredient is Na2O+K2O+B2O30.1~2.0% B2O3 / Bi2O30~0.04, and SiO2 / Bi2O3 0.4~0.65 Satisfy the relationship.

[0067] SiO2 in the glass frit forms the glass network and is also a crystallization component. In addition, a high SiO2 content in the glass frit is preferable in order to control the chemical, thermal, and mechanical properties. On the other hand, a low SiO2 content in the glass frit is preferable from the viewpoint of preventing the softening point Ts of the glass frit from becoming too high, which would reduce the fluidity of the glass. The SiO2 component in the filler is a component necessary for maintaining the strength and controlling the crystallinity of the ceramic color layer that covers the glass plate. 12 On the other hand, if the content of the SiO2 component in the filler is too high, the sinterability of the ceramic color layer decreases. From these viewpoints, the SiO2 content in the ceramic color layer, which is the total of inorganic components including glass frit, pigment, filler, etc., is preferably 15% by mass or more, and more preferably 20% by mass or more. The SiO2 content is preferably 30% by mass or less, more preferably 28.6% by mass or less, and even more preferably 25% by mass or less.

[0068] Bi2O3 in glass frit is a component that forms the glass network and is also effective as a low-softening component. Furthermore, when it coexists with SiO2 in glass frit, bismuth silicate crystals tend to precipitate. From the perspective of glass fluidity, a high Bi2O3 content in glass frit is preferable. On the other hand, if the Bi2O3 content in glass frit is too high, chemical durability decreases. In addition, adding a component containing Bi2O3 to the filler makes it easier to control the crystallinity. 12 It is also possible to include Bi2O3 as a compound such as From these viewpoints, the Bi2O3 content in the ceramic color layer is preferably 30 mass % or more, more preferably 40 mass % or more, and even more preferably 49 mass % or more. The Bi2O3 content is preferably 55 mass % or less.

[0069] Although B2O3 is not essential in glass frit, its inclusion acts as a flux and can improve the melting properties of glass. On the other hand, if the B2O3 content in the glass frit is too high, the mold releasability, acid resistance, and moisture resistance decrease. Furthermore, although the greater the amount of B2O3 in the filler, the better the strength retention of the coating layer. However, the reaction between the Bi2O3 in the glass frit and the B2O3 in the filler can inhibit crystallization, resulting in an increase in the glass phase and reduced releasability. From these viewpoints, the B2O3 content in the ceramic color layer is preferably 4% by mass or less, more preferably 3% by mass or less, and even more preferably 2% by mass or less.

[0070] Although the Al2O3 component in the glass frit or filler is not essential, in order to maintain the strength of the coating layer, the Al2O3 content in the ceramic color layer is preferably 1 mass% or more, more preferably 2 mass% or more. On the other hand, from the viewpoint of preventing a decrease in sinterability, the Al2O3 content is preferably 4 mass% or less. Note that Al2O3 may be contained not only as Al2O3 alone but also as a composite such as cordierite.

[0071] Although Li2O in the glass frit is not essential, its inclusion can significantly improve the melting property of the glass as a flux component. Furthermore, compared to Na and K, which react with water to form carbonates, Li has low solubility in water and is therefore less likely to form carbonates, making it an advantageous flux. On the other hand, from the viewpoint of preventing the thermal expansion coefficient from becoming too large, it is preferable that the amount of Li2O in the glass frit is small. From these viewpoints, the Li2O content in the ceramic color layer can be more than that of Na2O or K2O, and the content is preferably 3 mass% or less, more preferably 1.5 mass% or less, while the Li2O content is preferably 0.1 mass% or more, more preferably 0.5 mass% or more.

[0072] Although Na2O and K2O are not essential in the glass frit, their inclusion can improve the melting property of the glass, similar to Li2O in the glass frit. However, their tendency to increase the thermal expansion coefficient is stronger than that of Li2O in the glass frit. Furthermore, because Na2O and K2O in the glass frit are hydrophilic components, they affect moisture resistance. Therefore, it is necessary to reduce the total content of Na2O and K2O in the glass frit, and as a result, it is also necessary to reduce the total content of Na2O and K2O in the ceramic color layer. From these viewpoints, the total content of Na2O and K2O in the ceramic color layer is preferably 1.8 mass % or less, more preferably 1.4 mass % or less, even more preferably 1.0 mass % or less, and even more preferably 0.5 mass % or less.

[0073] The alkaline earth metal oxides in the glass frit are optional components. They facilitate vitrification. However, if the content is too high, the stability of the glass decreases and it becomes more susceptible to devitrification. Furthermore, the MgO component contained in the cordierite filler maintains the strength of the coating layer. However, as the content of alkaline earth metal oxides in the ceramic color layer increases, the sinterability decreases. From these viewpoints, the total content of alkaline earth metal oxides in the ceramic color layer is preferably 1% by mass or more, more preferably 4% by mass or more. On the other hand, the total content of alkaline earth metal oxides in the ceramic color layer is preferably 10% by mass or less. In this specification, the total content of alkaline earth metal oxides is the content expressed as (MgO + CaO + BaO + SrO). In addition to alkaline earth metal oxides alone, alkaline earth metal oxides may be contained as a composite, such as cordierite.

[0074] Although ZnO is not essential in the glass frit, its inclusion can reduce the thermal expansion coefficient. On the other hand, if the ZnO content in the glass frit is too high, the stability of the glass decreases and it becomes more susceptible to devitrification. From these viewpoints, the content of ZnO in the ceramic color layer is preferably 10% by mass or less, more preferably 6% by mass or less, and even more preferably 1% by mass or less.

[0075] Although TiO2 is not essential in the glass frit, it can be appropriately contained within a range that does not impair the homogeneity of the crystal phase derived from the glass frit for the purpose of adjusting the sintering temperature, chemical durability, thermal expansion coefficient, etc. On the other hand, if Bi2O3 is contained in the glass frit, it may react with the TiO2 component in the glass frit to precipitate bismuth titanate crystals, which may increase the thermal expansion coefficient. From these viewpoints, when TiO2 is contained, the TiO2 content in the ceramic color layer is preferably 0.1 mass% or more, while the TiO2 content in the ceramic color layer is preferably 5 mass% or less, more preferably 3 mass% or less, even more preferably 1.5 mass% or less, and even more preferably 1 mass% or less.

[0076] CeO2 in the glass frit is not essential, but can be included for the purpose of adjusting the firing temperature, thermal expansion coefficient, etc. On the other hand, there is a possibility that the homogeneity of the crystalline phase derived from the glass frit may be impaired, so it is preferable that the amount of CeO2 in the glass frit is small. From these viewpoints, the CeO2 content in the ceramic color layer is preferably 1 mass % or less.

[0077] In addition to the above components, glass frit contains CuO, Fe2O3, CoO, Nb2O5, Ta2O5, Sb2O3, Cs2O, P2O5, ZrO2, La2O3, SnO X (x is 1 or 2) and metal fluorides such as BiF3, NaF, KF, LiF, MgF2, CaF2, SrF2, BaF2, AlF3, and TiF4 can be contained as optional components. However, if the content of optional components is too high, the glass in the glass frit may become unstable and devitrify. Also, the glass transition point Tg and softening point Ts may increase. Therefore, when the glass frit contains these optional components, the total content thereof is preferably 10 mass% or less in the glass frit and 5 mass% or less in the ceramic color layer.

[0078] Although ZrO2 is not essential in the ceramic color layer, including it as a filler such as zircon can reduce the thermal expansion coefficient of the ceramic color layer. On the other hand, from the viewpoint of preventing a decrease in the sinterability of the ceramic color layer and suppressing crystallization due to reaction with Bi2O3 contained in the glass frit, the ZrO2 content in the ceramic color layer is preferably 2 mass% or less, more preferably 1 mass% or less, and even more preferably 0.5 mass% or less. Note that ZrO2 may be contained not only as ZrO2 alone but also as a composite such as zircon.

[0079] CuO, CrO, MnO, NiO, and CoO in the ceramic color layer are mainly pigments that are coloring components and contribute to the desired color, gloss, and opacity, i.e., transmittance. In the case of a black ceramic color layer, at least one component constituting the pigment is preferably CuO, CrO, MnO, NiO, or CoO to achieve the desired black color.

[0080] The total content of CuO, CrO, MnO, NiO, and CoO in the ceramic color layer is preferably 5% by mass or more, more preferably 10% by mass or more, from the viewpoint of obtaining a desired color tone, and is preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, and even more preferably 15% by mass or less, from the viewpoint of not inhibiting the sinterability of the ceramic color layer.

[0081] The total content represented by (Na2O + K2O + B2O3) in the ceramic color layer is preferably 0.1% by mass or more, from the viewpoint of obtaining good glass fluidity even in a low temperature range equivalent to 500° C. On the other hand, from the viewpoint of preventing the thermal expansion coefficient from becoming too high and obtaining high peel strength and good releasability after a humidity resistance test, the total content is preferably 5.0% by mass or less, more preferably 4.0% by mass or less, even more preferably 3.0% by mass or less, and even more preferably 2.0% by mass or less. Among Na2O, K2O, and B2O3, the content of B2O3 in the ceramic color layer is difficult to quantify by surface analysis. Therefore, considering that the difference between the total content in the ceramic color layer and the total content in the ceramic color composition before firing is small, the total content in the ceramic color composition can be considered to be the total content in the ceramic color layer. Therefore, the total content expressed as (Na2O + K2O + B2O3) in the ceramic color composition is preferably within the above range.

[0082] From the viewpoint of obtaining good moisture resistance, the content ratio expressed as B2O3 / Bi2O3 in the ceramic color layer is preferably 0 to 0.08, more preferably 0 to 0.07, and even more preferably 0 to 0.04. As with the total content expressed as (Na2O + K2O + B2O3), the content ratio expressed as B2O3 / Bi2O3 in the ceramic color composition can also be regarded as the ratio in the ceramic color layer. Therefore, the content ratio expressed as B2O3 / Bi2O3 in the ceramic color composition is also preferably within the above range.

[0083] From the viewpoint of obtaining good solder wettability, glass strength, and weather resistance, the content ratio (mass ratio) expressed by SiO2 / Bi2O3 in the ceramic color layer is preferably 0.3 or more, more preferably 0.35 or more, and even more preferably 0.4 or more, and is preferably 1.0 or less, more preferably 0.65 or less. This range of the mass ratio expressed by SiO2 / Bi2O3 is particularly suitable when the conductive layer contains a crystallized region derived from the glass frit. In addition, Bi4Si3O 12 The stoichiometry of SiO2 / Bi2O3 is 0.19 by mass ratio, but in the case of stoichiometry, Bi 12 SiO 20 Therefore, by increasing the SiO2 content in the ceramic color layer, Bi4Si3O 12The crystallinity of the glass increases, resulting in improved solder wettability and improved glass strength and weather resistance. On the other hand, if the SiO2 / Bi2O3 mass ratio is too high, the amount of Bi2O3 is small, and the proportion of elements other than SiO2 and Bi2O3 inevitably becomes large, which may result in the glass not meeting other properties required for vehicle glass.

[0084] The thickness of the ceramic color layer affects UV transmittance, acid resistance, weather resistance, glass strength, and cost. That is, if the ceramic color layer is too thin, for example, acid rain may seep in and cause the black color to discolor or become transparent, potentially preventing the ceramic color layer from fulfilling its intended function. From these perspectives, the thickness of the ceramic color layer is preferably 5 μm or more, more preferably 10 μm or more. Furthermore, a thicker ceramic color layer may be more susceptible to stress and increase costs. From these perspectives, the thickness of the ceramic color layer is preferably 30 μm or less, more preferably 20 μm or less, and more preferably less than 15 μm. The thickness of the ceramic color layer can be measured by cross-sectional SEM in the area where the conductive layer is not formed. Alternatively, the thickness can be measured by a contour measurement device in the area where the conductive layer is not formed, between the area where the ceramic color layer is formed and the area where the ceramic color layer is not formed, i.e., the area where only the glass plate is present.

[0085] The conductive layer is not particularly limited as long as it contains silver, and any conventionally known conductive layer can be used. For example, the conductive layer may be made of only silver. The conductive layer may also contain copper in addition to silver. In consideration of the influence of oxidation, a conductive layer made of silver, which is made of components that are resistant to oxidation, is more preferable.

[0086] The thickness of the conductive layer after firing is preferably 4 μm or more, more preferably 6 μm or more, and even more preferably 8 μm or more, from the viewpoint of bonding with solder. Furthermore, when solder wettability is taken into consideration, the thickness of the conductive layer is increased as much as possible, and in some cases, the surface layer can be scraped to improve solder wettability. On the other hand, an increase in the thickness of the conductive layer increases costs, and the increased stress caused by bonding the ceramic and metal reduces strength. Therefore, from these viewpoints, the thickness of the conductive layer is preferably 14 μm or less, more preferably 12 μm or less, and even more preferably 10 μm or less.

[0087] The glass plate may be any known glass that has been conventionally used for vehicle glass, such as soda lime glass, aluminosilicate glass, borosilicate glass, alkali-free glass, or quartz glass. Alternatively, the laminated glass may be formed by laminating two or more glass plates together via an interlayer film, and the glass plates that make up the laminated glass may be the same or different.

[0088] The material of the intermediate film is not particularly limited, but is preferably, for example, a thermoplastic resin. Examples of thermoplastic resins include plasticized polyvinyl acetal resins, plasticized polyvinyl chloride resins, saturated polyester resins, plasticized saturated polyester resins, polyurethane resins, plasticized polyurethane resins, ethylene-vinyl acetate copolymer resins, ethylene-ethyl acrylate copolymer resins, cycloolefin polymer resins, ionomer resins, etc. Furthermore, a resin composition containing a modified hydrogenated block copolymer, as described in Japanese Patent No. 6065221, can also be suitably used as a material for the interlayer film. The above thermoplastic resins may be used alone or in combination. The term "plasticized" refers to a resin that has been plasticized by adding a plasticizer. The material of the interlayer film may be a resin that does not contain a plasticizer, such as an ethylene-vinyl acetate copolymer resin.

[0089] Among these, plasticized polyvinyl acetal resins are more preferred because they have an excellent balance of various properties such as transparency, weather resistance, strength, adhesive strength, penetration resistance, impact energy absorbency, moisture resistance, heat insulation, and sound insulation. Examples of polyvinyl acetal resins include polyvinyl formal resins obtained by reacting polyvinyl alcohol (PVA) with formaldehyde, polyvinyl acetal resins in the narrow sense obtained by reacting PVA with acetaldehyde, and polyvinyl butyral resins (PVB) obtained by reacting PVA with n-butylaldehyde. PVB is particularly preferred because it offers an excellent balance of various properties, such as transparency, weather resistance, strength, adhesive strength, penetration resistance, impact energy absorption, moisture resistance, heat insulation, and sound insulation. These polyvinyl acetal resins may be used alone or in combination.

[0090] The glass plate may be tempered as needed. In particular, when the vehicle glass is an automobile window glass, such as a side glass or a rear glass, the glass may be tempered in accordance with required safety standards. The strengthening treatment may be a chemical strengthening treatment or a physical strengthening treatment (air-cooling strengthening treatment), but the physical strengthening treatment is preferred in terms of the strengthening treatment time and cost.

[0091] Physical tempering treatment can strengthen the glass surface by generating a compressive stress layer on the glass surface due to the temperature difference between the glass surface and the glass interior. Specifically, a compressive stress layer is generated by a temperature difference by a procedure other than slow cooling, such as by spraying a cooling medium onto a glass plate heated to a temperature above the softening point of the glass to rapidly cool it.

[0092] Chemical strengthening is a process in which glass is brought into contact with a metal salt by, for example, immersing the glass in a melt of a metal salt containing metal ions with a large ionic radius, and metal ions with a small ionic radius in the glass are replaced with metal ions with a large ionic radius. Typically, lithium ions are replaced with sodium ions or potassium ions, and sodium ions are replaced with potassium ions.

[0093] When chemical strengthening is performed, a conventionally known melt of metal salt, i.e., a molten salt, can be used. The conditions for the chemical strengthening treatment are appropriately selected taking into account the glass composition, the type of molten salt, etc. In addition, the chemical strengthening treatment may be performed in multiple stages, and cleaning with an alkaline solution or cleaning by plasma irradiation may also be performed.

[0094] The thickness of the glass plate is not particularly limited and may be set depending on the purpose. For example, when used in automobiles, the thickness of the glass plate is generally 0.2 to 5.0 mm, and preferably 0.3 to 3.0 mm. In laminated glass for use in automobiles, particularly as a windshield, the thickness of the glass plate located on the exterior side of the vehicle when installed in the automobile is preferably 1.1 mm or more, more preferably 1.8 mm or more, from the viewpoint of strength such as stone chip resistance. Furthermore, the thickness of the glass plate is preferably 3.0 mm or less, more preferably 2.8 mm or less, from the viewpoint of lightweight laminated glass. The thickness of the glass plate located on the interior side of the laminated glass when installed in the automobile is preferably 0.3 mm or more, from the viewpoint of handleability, and preferably 2.3 mm or less, from the viewpoint of lightweight laminated glass. The thicknesses of the two glass plates used in the laminated glass may be the same or different.

[0095] The vehicle glass may have a solder layer formed on at least a portion of the surface of the silver-containing conductive layer. The solder layer may be a lead-containing solder layer or a lead-free solder layer, but from the perspective of reducing environmental impact as exemplified by the ELV Directive, it is preferable to form a lead-free solder layer 4 as shown in Figure 2. Furthermore, since the vehicle glass according to this embodiment exhibits good solder wettability, a lead-free solder layer, which cannot form a thin coating film using low-melting-point solder, is preferable because it can enjoy the benefits of this effect. Since lead-free solder is harder than leaded solder, forming a lead-free solder layer tends to concentrate stress, making weather resistance an issue. However, the vehicle glass according to this embodiment can address the weather resistance issue without any problems.

[0096] The lead-free solder layer is a layer made of solder with a lead (Pb) content of 0.1% by mass or less, preferably 0.05% by mass or less, and the tin (Sn) content in the lead-free solder layer is preferably 95% by mass or more.

[0097] Examples of lead-free solder layers containing Sn as the main component include layers made of lead-free solder such as Sn-Ag, Sn-Ag-Cu, Sn-Zn-Bi, Sn-Cu, Sn-Ag-In-Bi, Sn-Zn-Al, Sn-Ag-In-Cu, and Sn-Ag-In-Cu-Zn-Ni solders. Of the above, Sn-Ag and Sn-Ag-Cu solders are preferred.

[0098] The solder wettability of vehicle glass is determined by the amount of glass frit that constitutes the ceramic color layer that migrates to the conductive layer. In the examples described below, Bi-based glass is used as the glass frit, and an Ag electrode is used as the conductive layer. All elements that migrate to the conductive layer surface are measured, and the quantitative value of Bi, which migrates more easily and has a higher concentration, is used to determine the wettability by the mass ratio of Bi to Ag (Bi / Ag). It is sufficient that the Bi / Ag mass ratio on the surface of the conductive layer is less than 0.10, preferably less than 0.09, more preferably 0.05 or less, and even more preferably 0.04 or less; the smaller the better. The Bi and Ag contents used to determine the Bi / Ag mass ratio are the ratio of the compositions (mass%) determined by surface SEM-EDX analysis or XPS in the area where the conductive layer is formed.

[0099] In SEM-EDX analysis, lowering the accelerating voltage makes it possible to analyze only the layer closer to the surface of the conductive layer. Considering the thickness of the ceramic color layer, the accelerating voltage for sufficient excitation is preferably 5 to 15 kV or less, more preferably 5 to 10 kV or less. Furthermore, since the conductive layer is a metal containing Ag, when quantifying by SEM-EDX analysis, the mass % of each element is quantified rather than converted into oxide. Furthermore, when measuring the mass concentration of O on the outermost surface of the conductive layer to determine the amount of migration, the accelerating voltage is preferably in the same range as above. Furthermore, solder wettability can be evaluated by measuring the peel strength of the lead-free solder layer after adhering it to the surface of the conductive layer. A correlation is found between a lower Bi / Ag mass ratio and a higher peel strength.

[0100] In addition to the glass plate, ceramic color layer, silver-containing conductive layer, and solder layer, the vehicle glass may also include a low-reflection film layer, a heat-insulating film layer, a UV-cut film layer, etc., within a range that does not impair the effects of the present invention.

[0101] Vehicle glass often has a curved surface due to its intended use, and it is preferable that the glass plate has a curved surface. The curved surface is preferably formed by the firing bending method described above. By forming a curved surface on the glass plate by heating, the ceramic color layer can be better bonded to the glass plate as a fired layer and simultaneously bent. However, this does not exclude the possibility of separately performing firing bending after forming the ceramic color layer and the conductive layer, or of providing the ceramic color layer and the conductive layer on a glass plate that already has a curved surface.

[0102] Furthermore, when the vehicle glass is an automobile glass, the glass plate is laminated and is used mainly as an automobile windshield or an automobile roof glass. That is, the vehicle glass according to the present embodiment is also suitably used as a laminated glass for a windshield or a roof glass.

[0103] The 0.1% fracture strength in a Weibull plot of static load strength at a portion where a silver-containing conductive layer is formed on the surface of the ceramic color layer of the vehicle glass is preferably 20 MPa or more, more preferably 30 MPa or more, even more preferably 35 MPa or more, and even more preferably 40 MPa or more. The upper limit of the 0.1% fracture strength is not particularly limited, but is usually 70 MPa or less. The 0.1% breaking strength in the Weibull plot of static load strength was determined by taking the value corresponding to 1 / 1000 strength from the Weibull plot obtained in accordance with JIS 1625 (2010).

[0104] The weather resistance of a terminal joined to vehicle glass via a lead-free solder layer can be determined by a tensile strength test and a heat cycle strength test after a humidity resistance test. In the moisture tensile strength test, terminals are joined via a lead-free solder layer, and the peel strength is measured after 500 hours under conditions of 80°C and 96% RH. If this peel strength is 100 N or more, it can be determined that peeling is unlikely to occur in actual commercial applications and that the moisture resistance is excellent. Therefore, the peel strength is preferably 100 N or more, more preferably 150 N or more, and even more preferably 200 N or more. There is no particular upper limit for the peel strength.

[0105] The appearance is inspected visually at the peel interface. If the peel strength is 100 N or more, the adhesive strength is sufficient, so the terminal is forcibly peeled off with a force greater than the peel strength. In this case, the peeling occurs due to cohesive failure of the ceramic color layer or the glass plate. On the other hand, if the peel strength is 100 N or less, peeling occurs at the interface between the ceramic color layer and the conductive layer, cohesive failure occurs within the conductive layer, or peeling occurs at the interface between the conductive layer and the solder layer. In these cases, peeling of the terminal occurs over time, and if the terminal is a heating wire, for example, this means that it is difficult to stably pass electricity through it.

[0106] The heat cycle strength test involves heating a terminal joined via a lead-free solder layer to 105°C and then cooling it to -40°C, with one cycle consisting of 60 cycles, followed by an appearance inspection and measurement of static load strength. The material's resistance to thermal cycles can lead to cracks or breakage as a result of repeated stress and strain caused by thermal cycles. Therefore, the appearance inspection involves visually observing the ceramic color layer from the glass plate side to check for the presence of cracks or breakage.

[0107] The static load strength after the heat cycle strength test is measured by measuring the 0.1% fracture strength in a Weibull plot of the static load strength at a portion where a silver-containing conductive layer is formed on the surface of the ceramic color layer. The 0.1% fracture strength in the Weibull plot after the heat cycle strength test is preferably 20 MPa or more, more preferably 30 MPa or more, even more preferably 35 MPa or more, and even more preferably 40 MPa or more. There is no particular upper limit, but it is usually 70 MPa or less. The 0.1% breaking strength in the Weibull plot of static load strength was determined by taking the value corresponding to 1 / 1000 strength from the Weibull plot obtained in accordance with JIS 1625 (2010).

[0108] <Method of manufacturing vehicle glass> The glass plate for the vehicle glass may be either a manufactured product or a commercially available product. The size of the glass plate may be determined appropriately depending on the application. For example, when the vehicle glass is used as a windshield for an automobile, a glass plate measuring 500 to 1300 mm x 1200 to 1700 mm x 1.6 to 2.5 mm is prepared. The glass plate may be a single sheet or may be a laminated glass in which two or more sheets of glass are bonded together.

[0109] A ceramic color layer is formed on at least a partial area of ​​the surface of the glass plate. The ceramic color layer is prepared using a paste-like ceramic color composition as a precursor, which contains glass frit, a pigment, and, if necessary, various fillers.

[0110] The glass frit in the ceramic color composition is selected so as to have a composition that satisfies the properties described above in <Vehicle Glass>. The ceramic color composition containing this glass frit, filler, and pigment becomes a ceramic color layer at a temperature near the bending temperature of the glass sheet, i.e., in the temperature range of 500 to 700°C. By precipitating a large amount of crystals with bismuth silicate as the main crystalline phase in this temperature range, strength and releasability can be ensured.

[0111] In order to obtain various properties, the glass frit in the ceramic color composition may be one type of glass frit or a mixture of two or more types of glass frits.Furthermore, two or more types of glass frits having the same composition but different particle sizes may be mixed and used as appropriate.

[0112] From the viewpoint of good baking, the softening point Ts of the glass frit is preferably 500° C. or higher, more preferably 520° C. or higher, and more preferably 580° C. or lower, more preferably 540° C. or lower. When two or more types of glass frits are used in combination, it is more preferable that at least one of the glass frits has a softening point within the above range, and it is even more preferable that the softening points of all the glass frits are within the above range.

[0113] Glass frit particle diameter D 50 If the particle size is too small, the specific surface area will increase, making it more likely to adsorb moisture and carbon dioxide from the atmosphere. In this case, bubbles may form within the ceramic color layer when it is formed in the temperature range of 500 to 700°C, which may result in a decrease in transmittance, strength, etc. From these viewpoints, when the volume-based particle size distribution curve measured by the laser diffraction scattering method shows two peaks, the first peak is preferably between 0.1 and 1.0 μm, more preferably between 0.3 and 1.0 μm, even more preferably between 0.3 and 0.9 μm, even more preferably between 0.3 and 0.8 μm, and particularly preferably between 0.5 and 0.8 μm. From the viewpoint of sinterability, the second peak of the bimodal distribution is preferably between 1.0 and 3.0 μm, more preferably between 1.0 and 2.5 μm, and even more preferably between 1.0 and 2.0 μm.

[0114] When the particle size distribution of the glass frit is bimodal or more, the ceramic color composition in paste form can be more closely packed when screen-printed, which is advantageous in terms of sinterability. In order to make the particle size distribution of the glass frit bimodal or more, the conditions for pulverizing the glass frit may be optimized, or a mixture of glass frits of each single particle size may be used. Furthermore, the glass frit may be classified to obtain a single particle size distribution. The particle size of the glass frit is the cumulative median diameter D of the volume-based particle size distribution. 50 and is a value measured by a laser diffraction scattering method.

[0115] Maximum particle diameter of glass frit D max From the viewpoint of preventing clogging when forming on the surface of a glass plate by screen printing, the maximum particle diameter D of the glass frit is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 15 μm or less. Furthermore, when the ceramic color composition is sintered, if coarse particles remain undissolved, this may cause deterioration of sinterability and a decrease in strength. From these viewpoints, the maximum particle diameter D of the glass frit max is even more preferably 10 μm or less.

[0116] The glass frit content in the ceramic color composition is preferably 60% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 70% by mass or more from the viewpoint of obtaining good sinterability. On the other hand, from the viewpoint of preventing the thermal expansion coefficient of the ceramic color layer from becoming too high and reducing the strength of the vehicle glass, the glass frit content is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. In this specification, the content in the ceramic color composition means the content in the total amount of inorganic components among the components constituting the ceramic color composition, and does not take into account the content of organic components. Therefore, the content of glass frit in the ceramic color composition is the amount excluding the content of fillers and pigments contained in the ceramic color composition.

[0117] The content of the pigment in the ceramic color composition is preferably 5% by mass or more, more preferably 10% by mass or more, from the viewpoint of obtaining a desired color tone. Also, from the viewpoint of not inhibiting the sinterability of the ceramic color layer, the content of the pigment is preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0118] Among the fillers, the content of the crystallization accelerator in the ceramic color composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 1% by mass or more, from the viewpoint of obtaining good crystallinity of the glass frit. Furthermore, if the crystallinity of the ceramic color layer becomes too high, the amount of glass phase present becomes too small, and the color tone of the ceramic color layer becomes cloudy due to diffuse reflection. Therefore, the content of the crystallization accelerator is preferably 10% by mass or less, more preferably 5% by mass or less.

[0119] When the amount of the crystallization accelerator added is large, the presence or absence of the crystallization accelerator can be confirmed by cross-sectional analysis of the crystallized region in the obtained ceramic color layer by SEM-EDX. The powder added as a crystallization accelerator is often pulverized and remains in a crushed form in the ceramic color layer. In contrast, the precipitated crystals have shapes such as single needle, needle-like, plate-like, square plate-like, fan-like, star-like, etc., and can be distinguished from the added powder. However, since the amount of the crystallization accelerator actually added is small, it is difficult to determine its presence or specific content from the ceramic color layer. In this case, the entire crystallized region can be considered to be the crystallized region derived from the glass frit.

[0120] Crystallization accelerator particle size D 50 In order to disperse the particles uniformly throughout the ceramic color composition, the particle size is preferably 2 μm or less, more preferably 1.5 μm or less, even more preferably 1.0 μm or less, and even more preferably 0.8 μm or less. On the other hand, if the particles are made too fine, the specific surface area becomes too large, making it easier to adsorb moisture and carbon dioxide gas from the atmosphere, and from the viewpoint of preventing a decrease in transmittance, strength, etc. due to foaming within the layer during ceramic color layer formation, the particle size is preferably 0.02 μm or more, more preferably 0.1 μm or more, and even more preferably 0.3 μm or more.

[0121] Of the fillers, the content of the low expansion filler in the ceramic color composition is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, from the viewpoints of controlling the thermal expansion coefficient, good fluidity, maintaining the strength of the glass plate, releasability, etc. Furthermore, from the viewpoint of not inhibiting the sinterability of the glass frit, the content of the low expansion filler is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.

[0122] The thermal expansion coefficient of the ceramic color composition at 50 to 350°C is set to 50 × 10 -7 / ℃ or more is preferable, 55 × 10 -7 / ℃ or more is more preferable, and 60×10 -7 / °C or more is more preferable, and 130 × 10 -7 / ℃ or less is preferable, and 100 × 10 -7 / ℃ or less is more preferable, and 85×10 -7 / ℃ or less is more preferable, and 77×10 -7 / °C or less is even more preferable.

[0123] An oxidizing agent may be added as a filler to sufficiently decompose the organic vehicle, but considering the deterioration of the sinterability of the ceramic color layer, the content of the oxidizing agent is preferably 10 mass % or less.

[0124] The ceramic color composition is prepared by dispersing glass frit, pigment, and optionally filler in the above-mentioned ratio in an organic vehicle to form a paste. The organic vehicle is a vehicle containing an organic binder and is used to form the ceramic color composition into a paste.

[0125] An organic vehicle is a polymer compound dissolved in a solvent. Conventional polymer compounds and solvents can be used. Examples of polymer compounds that can be used include ethyl cellulose, acrylic resin, styrene resin, phenolic resin, and butyral resin. Examples of solvents that can be used include α-terpineol, butyl carbitol, butyl carbitol acetate, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether, and diethylene glycol monobutyl ether.

[0126] The concentration of the polymer compound in the organic vehicle is not particularly limited, but is usually 0.5 to 15% by mass. Furthermore, in consideration of printability during screen printing, the organic vehicle containing the polymer compound in the paste ceramic color composition is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. Meanwhile, in consideration of binder removal, the organic vehicle is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0127] The paste-like ceramic color composition is applied to at least a partial area of ​​the surface of the glass plate. The ceramic color layer is applied by screen printing, ink jet printing, electronic printing, etc. and adjusted to a desired thickness. For example, it is preferable to print using a #150 to #400 mesh screen.

[0128] Next, the applied ceramic color composition is dried and baked onto the glass plate. Drying is carried out, for example, at room temperature to 200°C for 20 to 40 minutes. Baking is carried out, for example, using a heating furnace such as a far-infrared (IR) heating furnace, but baking may also be carried out after applying a silver-containing conductive layer to at least a portion of the surface of the dried ceramic color composition. Furthermore, baking and bending of the glass may also be carried out simultaneously.

[0129] The conductive layer containing silver is formed by preparing a conductive paste containing silver and applying it by screen printing, ink jet printing, electronic printing, etc. For example, it is preferable to apply it by screen printing. The organic vehicle for forming the paste can be the same as that for the ceramic color composition. The conductive paste layer has a thickness of, for example, 1 to 20 μm, and is then dried, for example, at a temperature of 80 to 140° C. for 1 to 15 minutes.

[0130] The heating temperature for firing the ceramic color composition or the conductive paste layer is preferably 500° C. or higher, more preferably 590° C. or higher, and preferably 700° C. or lower, more preferably 650° C. or lower. The heating time is preferably 3 minutes or longer, more preferably 10 minutes or longer, and preferably 30 minutes or shorter, more preferably 20 minutes or shorter.

[0131] By firing, the ceramic color composition is fired onto the glass plate to form a fired layer, and at least a portion of the glass frit is crystallized to form a ceramic color layer containing the glass frit, a pigment, and optionally a filler, and the conductive paste becomes a conductive layer, thereby obtaining a vehicle glass. Heating may be carried out in two or more stages, with baking and crystallization being carried out in sequence.

[0132] The overall structure (composition) of the ceramic color layer can be determined by direct analysis of the surface or cross section using fluorescent X-rays, SEM-EDX, EPMA (electron probe microanalyzer), SIMS (secondary ion mass spectrometry), and XPS. In addition, all elements can be measured by cutting out only the ceramic color layer using a micromanipulator or similar tool and combining this with ICP-AES (inductively coupled plasma atomic emission spectrometry) or ICP-MS (inductively coupled plasma mass spectrometry).

[0133] The amount of crystalline pigment and filler is determined by quantitative analysis of standard samples using SEM-EDX and XRD, and the remainder is calculated as the amount of glass frit. This allows the ratio of glass frit, pigment, and filler in the ceramic color layer to be determined.

[0134] The particle size and particle size distribution of the filler in the ceramic color layer can be determined by observing the filler components with cross-sectional SEM-EDX, performing image analysis of the filler particle size distribution with WinROOF manufactured by Mitani Shoji, and deriving a frequency distribution graph. Furthermore, the glass composition can be determined from the above combination, and thermal properties such as the softening point can also be calculated by regression calculation of the determined glass composition.

[0135] From the viewpoint of cost, it is preferable to perform firing bending at the same time as the firing to make the glass sheet into a vehicle glass having a curved surface. However, this does not exclude the firing bending of the glass sheet being performed separately from the firing of the ceramic color layer. When firing bending is performed simultaneously with firing the ceramic color layer, the glass sheet is bent while being maintained at the firing temperature. The heating temperature during bending is preferably near the softening point Ts of the glass sheet, and preferably about Ts±100°C.

[0136] Methods for bending glass sheets include press bending, in which the glass sheet is heated to or above its softening point and then pressed against a mold of a desired shape to bend it, and gravity bending, in which the glass sheet is bent by its own weight. Press bending using a press such as a hot press is preferred from the viewpoint of cleaning the surfaces of the ceramic color layer and the conductive layer and obtaining a desired shape. Also, in terms of UV reflection, press bending is preferred from the viewpoint of suppressing high-angle distortion.

[0137] In gravity bending, a glass sheet is bent using a gravity bending device, but unlike press bending, it does not require a mold of the desired shape, which is advantageous in terms of cost. The glass sheet may have a single-bend shape formed by bending only in one direction, for example, only in the longitudinal direction or the vertical direction of the automobile when attached to an opening of the automobile. Alternatively, the glass sheet may have a compound-bend shape formed by bending only in the longitudinal direction and the vertical direction. When the glass sheet is bent and curved to a predetermined curvature, the radius of curvature of the glass sheet is, for example, 1,000 to 100,000 mm.

[0138] In this embodiment, the Bi / Ag mass ratio can be set to less than 0.10 without grinding or polishing the surface of the conductive layer, and good solder wettability can be maintained. However, when the above-mentioned retention is taken into consideration, in order to obtain better solder wettability, the surface of the conductive layer may be ground or polished to reduce the thickness of the outermost layer and further reduce the Bi / Ag mass ratio. The grinding or polishing range is preferably 0 to 2 μm from the surface of the fired conductive layer, more preferably 0 to 0.15 μm, even more preferably 0 to 0.1 μm, and even more preferably 0 to 0.05 μm. However, in order to fulfill the role of the conductive layer, the thickness to be ground or polished is preferably 1 / 20 or less of the thickness of the fired conductive layer, more preferably 1 / 50 or less, and even more preferably 1 / 100 or less.

[0139] In order to improve the solder wettability of the glass plate after firing, it is preferable to grind or polish the surface layer side within 0 to 2 μm from the surface of the conductive layer after firing to make the Bi / Ag mass ratio of the outermost surface 0.05 or less, more preferably to grind or polish within 0 to 0.5 μm to make the Bi / Ag mass ratio of the outermost surface 0.05 or less, more preferably to grind or polish within 0 to 0.1 μm to make the Bi / Ag mass ratio of the outermost surface 0.05 or less, and even more preferably to grind or polish within 0 to 0.05 μm to make the Bi / Ag mass ratio of the outermost surface 0.05 or less. Note that it is more preferable that the Bi / Ag mass ratio of the outermost surface after the grinding or polishing is 0.04 or less, and the smaller the better. However, in order for the conductive layer to function, the thickness to be ground or polished is preferably 1 / 20 or less of the thickness of the conductive layer after firing, more preferably 1 / 50 or less, and even more preferably 1 / 100 or less. This allows the metal atoms of the conductive layer to spread and cover the glass phase portion in the glass frit floating on the surface, thereby reducing the area of ​​the glass phase portion in the glass frit and improving solder wettability.

[0140] Grinding or polishing the surface of the conductive layer can also have an anchoring effect, improving the adhesive strength of the solder on the conductive layer. When grinding or polishing the conductive layer, steel wool, sandpaper, a sand eraser, or an abrasive disk made of felt or sponge material with abrasive stones can be used.

[0141] The vehicle glass may have a solder layer formed on at least a partial region on the surface of the silver-containing conductive layer, and more preferably has a lead-free solder layer formed thereon.

[0142] The lead-free solder layer is preferably formed via a flux from the viewpoint of removing foreign matter and oxide films on the surface of the conductive layer and realizing good bonding, and more preferably formed via a halogen-free flux from the viewpoint of environmental protection.

[0143] According to the JPCA ES01 (2003) standard, for example, halogen-free flux is a flux with a chlorine (Cl) content of 900 ppm or less, a bromine (Br) content of 900 ppm or less, and a combined Cl and Br content of 1500 ppm or less. Also, according to the JEITA ET 7304 (2009) standard, it is a flux with a Cl content of 1000 ppm or less, a Br content of 1000 ppm or less, and a fluorine (F) content of 1000 ppm or less.

[0144] The flux may be pre-contained in the lead-free solder or may be applied separately, but it is preferable to apply it separately from the viewpoint of surface cleanliness and ease of solder adhesion. The presence or absence of flux can often be determined by visual inspection. [Example]

[0145] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these. Example 8 is a comparative example, and Example 9 is a reference example.

[0146] [Example 1 to Example 9] Glass raw materials were prepared and mixed according to the composition shown in Table 1, and melted at 1100 to 1500° C. to obtain a vitrified product. The obtained vitrified product was pulverized in a ball mill to obtain glass frit. The softening point of the obtained glass frit was measured using a differential thermal analyzer (Rigaku Thermo plus EV02 differential type differential thermobalance TG-DTA8122) by raising the temperature to 700°C at a rate of 10°C / min, and the softening point (unit: °C) corresponding to the fourth inflection point was measured. The particle size distribution of the glass frit and filler was measured using a particle size distribution analyzer (Microtrac MT3300EXII, manufactured by Microtrac Bell). The measurement conditions were as follows: Solvent: 20 mL of water, Ultrasonic dispersion for 2 minutes, transparent, non-spherical, Particle refractive index 1.75, Solvent refractive index 1.33. The particle size distribution curve on a volume basis measured by the laser diffraction scattering method was judged to be unimodal or bimodal.

[0147] The resulting glass frit was mixed with the pigment Cu(CrMn)2O4 (TOMATEC, manufactured by Asahi Kasei Kogyo Co., Ltd.) or (Co,Fe)(Ni,Cr)2O4 (manufactured by Nitto Pigment Co., Ltd.), a low-expansion filler, a crystallization accelerator, and an oxidizing agent or reducing agent in the ratios shown in Table 1 so that the resulting ceramic color layer would have the composition shown in Table 2. The crystallization accelerator was added so that it was 0.1% by mass relative to the resulting ceramic color layer. The oxidizing agent was added so that it was 0.1% by mass relative to the resulting ceramic color layer. Note that "---" in Tables 1 and 2 means that it was not added. In Example 9, zirconium boride was used as the reducing agent, and it was added so that it was 2% by mass relative to the resulting ceramic color layer. The thermal expansion coefficient of the ceramic color composition was calculated as the average linear thermal expansion coefficient at 50 to 350° C. using a differential thermal dilatometer (Rigaku Corporation, Thermo plus EV02, horizontal dilatometer TDL8411). The results are shown in Table 1.

[0148] To 80 parts by mass of the mixture that will become the ceramic color composition, 20 parts by mass of a vehicle solution such as α-terpineol in which ethyl cellulose has been dissolved was added and kneaded, and the mixture was uniformly dispersed using a three-roll mill to obtain a paste-like ceramic color composition adjusted to the desired paste viscosity.

[0149] The paste-like ceramic color composition obtained above was screen-printed on the entire surface of a 10 cm × 10 cm × 3.5 mm soda lime silica glass plate in a size of 9 cm × 9 cm using a #180 mesh, and dried at 120 ° C. Next, silver paste (silver paste manufactured by DuPont) was screen-printed on the surface of the dried ceramic color composition layer in a size of 3 cm × 3 cm or 9 cm × 9 cm, and dried to form a conductive paste layer. The glass plate on which the ceramic color composition layer and the conductive paste layer were formed was then fired at 590 to 650°C for 4 or 7 minutes and cooled to room temperature. Next, terminals were joined via a lead-free solder layer. The lead-free solder layer was formed using lead-free solder with an Sn content of 98% by mass and an Ag content of 2% by mass. As a result, a vehicle glass having a ceramic color layer as a fired layer, a silver-containing conductive layer, and a lead-free solder layer formed thereon was obtained. The thickness of each ceramic color layer was 11 to 13 μm.

[0150] [Table 1]

[0151] [Table 2]

[0152] [evaluation] The ratios of glass frit, pigment, and filler in the ceramic color layer were confirmed to be the ratios shown in Table 1 by XRD and SEM-EDX quantitative analysis.

[0153] The overall composition of the ceramic color layer, except for B2O3 and Li2O, was confirmed to be the same as the original composition by SEM-EDX and quantitative analysis.

[0154] The ceramic color layer was subjected to X-ray powder diffraction measurement to identify the precipitated crystalline phase. The measurement was performed using a Rigaku MiniFlex600 under the conditions of CuKα radiation, voltage 40 kV, current 15 mA, scan width 0.02°, 2θ = 10 to 60°, and scan speed 2° / min. The results are shown in Table 1. In Examples 1 to 8, Bi4Si3O 12 The thermal expansion coefficient of this crystal is low, 7 × 10 -7 / °C. On the other hand, Bi2SiO5 crystals were observed in Example 9. Even in light of the above thermal expansion coefficient values, it is presumed that Bi2SiO5 crystals exhibit a high thermal expansion coefficient. Also, the crystallinity X=I c / (I c +I a )×100 (I c :Crystalline scattering integrated intensity, I a The crystallinity of each sample was calculated according to the formula (crystallinity = amorphous scattering integrated intensity), and is shown in Table 2.

[0155] Vehicle glass with a conductive layer applied on a ceramic color layer was fired at 590 to 650°C, and the Bi / Ag mass ratio on the outermost surface of the silver-containing conductive layer was measured using SEM-EDX analysis (Hitachi High-Tech, FE-SEM / EDX Regulus 8220) at an accelerating voltage of 10 kV. SEM-EDX analysis was performed on the outermost surface of the conductive layer to quantify the amount of elements including Bi, and the Bi / Ag mass ratio was calculated by normalizing the Bi with Ag. The results are shown in Table 3. Figure 3 shows a graph of the Bi / Ag mass ratio over the firing temperature range.

[0156] In addition, the amount of migration after firing the vehicle glass at 630°C was calculated by multiplying the mass concentration of O (oxygen) at the outermost surface of the silver-containing conductive layer by the thickness of the silver-containing conductive layer. The mass concentration of O (oxygen) at the outermost surface of the silver-containing conductive layer was measured by SEM-EDX analysis (Hitachi High-Tech, SEM / EDX TM4000Plus AZtecOne) at an acceleration voltage of 15 kV, similar to the Bi / Ag mass ratio. The thickness of the silver-containing conductive layer was also measured by cross-sectional SEM using the same device. The amounts of migration obtained as above are shown in Table 3.

[0157] The Bi / Ag mass ratio in Table 3 is shown for a representative temperature of 630°C within the firing temperature range, as well as the maximum and average values ​​for firing temperatures in the range of 590 to 650°C. In Examples 1 to 7, which are working examples, the Bi / Ag mass ratio was less than 0.10 over the entire temperature range of 590 to 650° C., based on the maximum value of the Bi / Ag mass ratio in the temperature range of 590 to 650° C. On the other hand, in Example 8, which is a comparative example, the value at 630° C. was 0.10, with a maximum value of 0.23 and an average value of 0.10, all of which were values ​​above 0.10, indicating poor solder wettability.

[0158] A more detailed study will be carried out. Example 6 is shown as an example of the working example. The Bi / Ag mass ratio was a low value of 0.04 or less throughout the entire temperature range of 590 to 650°C. On the other hand, in Example 8, which is a comparative example, the Bi / Ag mass ratio was 0.16 when the firing temperature was 640°C and 0.23 when the firing temperature was 650°C, resulting in poor solder wettability, especially at high temperatures. Furthermore, in Example 9, which is a reference example, the Bi / Ag mass ratio was 0.09 when the firing temperature was 630°C, which was less than 0.10, but the Bi / Ag mass ratio was 0.12 when the firing temperature was 610°C and 0.11 when the firing temperature was 650°C. This resulted in poor solder wettability not only at the maximum and average values ​​shown in Table 3, but also at low temperatures.

[0159] Furthermore, when the amount of migration, which is expressed as the product of the mass concentration of O (oxygen) on the outermost surface of the conductive layer and the thickness of the conductive layer, shown in Table 3, was examined, it was found that the amount of migration was 75% μm or less in all of Examples 1 to 5 and 7, suggesting a correlation with the total content of Na2O + K2O + B2O3 shown in Table 1. That is, when the total content of Na2O + K2O + B2O3 was 4.0 mass% or less, the amount of migration decreased, and when this total content was 3.0 mass% or less, the amount of migration tended to decrease even more significantly.

[0160] Since solder wettability is determined by the amount of glass frit that constitutes the ceramic color layer that migrates to the conductive layer, the Bi / Ag mass ratio in the outermost layer of the ceramic color layer can be used as an indicator to determine whether the solder wettability is good or bad. Meanwhile, the amount of migration expressed as the product can also be used as an indicator to determine whether the solder wettability is good or bad. Therefore, Table 3 also shows the results of solder wettability based on the Bi / Ag mass ratio and the amount of migration expressed as the product. That is, when lead-free solder is soldered onto the conductive layer, if it is easy to adhere and the solder wets and spreads sufficiently, the solder wettability is very good and is indicated by "○", if it is possible to adhere to the lead-free solder but the solder does not wet and spread easily, the solder wettability is good and is indicated by "△", and if the solder does not wet and spread when lead-free soldering, the solder wettability is poor and is indicated by "×".

[0161] As a result, the vehicle glasses of Examples 1 to 7 achieved better solder wettability, and even though the solder layer formed on at least a portion of the surface of the silver-containing conductive layer was a lead-free solder layer, it was shown that the terminals could be bonded with high strength, and this was particularly notable for the vehicle glasses of Examples 1 to 5 and 7. Such vehicle glasses further suppress the floating of the glass phase in the glass frit from the ceramic color layer to the conductive layer surface, and can also suitably suppress cracking of the glass due to stress concentration and peeling of the ceramic color layer.

[0162] [Table 3]

[0163] [Table 4]

[0164] All ceramic color layers were black ceramic layers, and their color tones were measured in terms of the lightness index L* value in the CIE 1976 (L*a*b*) color space (CIELAB) in accordance with JIS Z 8722 (2000). A Konica Minolta CR-400 color difference meter was used, with the light source set to CIE standard illuminant D65, the illumination and light receiving method set to condition a ((45-n) [45-0]), and the measurement diameter set to 3 mm. The results are shown in Table 4, and since an L* value in the range of 20 to 25 is preferred, values ​​within the range of 20 to 25 are marked with a circle.

[0165] The static load strength of the vehicle glass was measured using a general-purpose compression tester with a ring-on-ring method at a compression rate of 1 mm / min. A Weibull plot was performed according to JIS 1625 (2010) to determine the 0.1% fracture strength, which corresponds to 1 / 1000 of the strength. The results are shown in Table 4. For vehicle glass having a conductive layer formed on a ceramic color layer, a 0.1% fracture strength of 20 MPa or more in the Weibull plot of static load strength is sufficient, and is therefore indicated by "O." However, a value of 30 MPa or more is more preferable, and the higher the better.

[0166] The vehicle glass to which the terminals of Examples 1 to 9 were bonded was left for 500 hours under conditions of 80°C and 96% RH, after which the peel strength of the terminals was measured by pulling them vertically using a general-purpose tensile / compression tester manufactured by Shimadzu Corporation, and the value at the time of peeling was determined. The results are shown in "Peel strength after humidity resistance test" in Table 4. Furthermore, in Example 9, the solder wettability of the lead-free solder and the 0.1% fracture strength in the Weibull plot were both low, and the peel strength could not be measured properly, so it was marked "---".

[0167] The vehicle glass to which the terminals of Examples 1 to 9 were joined was heated to 105°C and then cooled to -40°C, which constituted one cycle. After 60 cycles, the appearance was inspected and the peel strength was measured. The results are shown in the "Heat cycle test result" in Table 4. In addition, in Example 9, the solder wettability of the lead-free solder and the 0.1% fracture strength in the Weibull plot were low, and the peel strength could not be measured properly, so it was marked "---". A peel strength of 100 N or more after the moisture resistance test was evaluated as "Good", and a peel strength of less than 100 N was evaluated as "Poor". Furthermore, a vehicle glass that showed no visible change in appearance after the heat cycle test was evaluated as "Good", while a glass with a change in appearance such as cracks was evaluated as "Poor".

[0168] Table 5 shows the composition of the ceramic color layer surface after a humidity resistance test for vehicle glass with a conductive layer formed on top of the ceramic color layer. The peeling interface after the humidity resistance test is the interface between the ceramic color layer and the conductive layer, and the concentration at this interface should be determined. However, in the area of ​​the ceramic color layer where the conductive layer is not formed, migration occurs in both directions in a region approximately several hundred microns from the edge of the conductive layer. Therefore, the composition can be considered to be the same as that of the outermost surface of the ceramic color layer where the conductive layer is not formed. Therefore, the concentration of hydrophilic components at the interface between the ceramic color layer and the conductive layer can be determined by analyzing the composition of the outermost surface of the ceramic color layer in a region within several hundred microns from the edge of the conductive layer.

[0169] Therefore, the composition measured by SEM-EDX for a portion of the ceramic color layer where no conductive layer was formed, 50 μm away from the end of the conductive layer, is shown in Table 5. These are expressed as mass% on an oxide basis. Also, blank cells in Table 5 indicate that the content was below the detection limit. Table 5 does not list boron (B), but this does not mean that B is not contained, but rather that it was not measured due to the difficulty of quantifying it. Because B is a light element, the count number of the EDX detector decreases, which reduces the reliability of the quantitative analysis value. Therefore, we quantified the elements after oxygen (O) in the periodic table. Note that while XPS generally allows for the quantification of B, the binding energy of boron oxide (B1s: 180 eV) and the binding energy of barium oxide (Ba 4p 3 / 2 Since the peak overlaps with that at 180 eV, it is difficult to quantify B in this system using XPS.

[0170] [Table 5]

[0171] The cross sections of the vehicle glasses of Examples 5 and 8 were observed with a scanning microscope (FE-SEM / EDX Regulus8220, manufactured by Hitachi High-Technologies, and SEM / EDX SU3500, manufactured by Hitachi High-Technologies). The SEM image of Example 5 is shown in FIG. 4, and the SEM image of Example 8 is shown in FIG. 5.

[0172] In Figure 4, a small amount of glass phase a, which is residual glass, has migrated from the ceramic color layer 2 to the silver-containing conductive layer 3, but many voids remain within the conductive layer 3, and the cross-sectional SEM image also shows that the amount of migration is small. Furthermore, crystallized regions b derived from the glass frit were confirmed near the surface of the silver-containing conductive layer 3, and almost no glass phase was confirmed on the outermost surface. On the other hand, in Figure 5, a large amount of glass phase a, which is residual glass, migrates from the ceramic color layer 2 to the silver-containing conductive layer 3. There are also fewer voids in the conductive layer 3, and the cross-sectional SEM image also shows that a large amount has migrated. Note that the glass phase a in Figure 5 is enclosed by a lead line and a circle for ease of understanding. In other words, this represents only a portion of the glass phase that has migrated to the conductive layer, and does not represent the entirety of it. Furthermore, no crystallized regions like those in Figure 4 were observed on the surface of the silver-containing conductive layer 3, and a large amount of amorphous glass phase a was confirmed on its outermost surface.

[0173] This indicates that during the process of forming the ceramic color layer and the conductive layer, a large amount of the glass frit contained in the ceramic color composition and the ceramic color layer migrates to the conductive layer in the glass phase without crystallizing. In this way, migration in the glass phase increases the Bi / Ag mass ratio on the outermost surface of the conductive layer, and the solder wettability decreases. On the other hand, in the present invention, it was found that by suppressing the migration in the glass phase, the mass ratio of Bi / Ag on the outermost surface of the conductive layer can be reduced, and good solder wettability can be achieved.

[0174] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2021-025595) filed on February 19, 2021, the contents of which are incorporated herein by reference. [Explanation of symbols]

[0175] 1 glass plate 2 Ceramic color layer 3 Conductive layer 4 Lead-free solder layer 10 Vehicle glass a Glass phase b Crystallization region

Claims

1. A vehicle glass comprising a glass plate, a ceramic color layer formed on a surface of the glass plate, and a conductive layer containing silver formed on the surface of the ceramic color layer, the ceramic color layer is a fired layer containing glass frit and a pigment, the glass frit contains Bi, a lead-free solder layer is formed on at least a portion of the surface of the silver-containing conductive layer; The vehicle glass, wherein the mass ratio of Bi / Ag at the outermost surface of the silver-containing conductive layer is less than 0.

09.

2. 2. The vehicle glass according to claim 1, wherein a migration amount represented by the product of a mass concentration of O (oxygen) at an outermost surface of the silver-containing conductive layer and a thickness of the silver-containing conductive layer is 75% μm or less.

3. The vehicle glass according to claim 1 or 2, wherein the conductive layer containing silver includes a crystallized region derived from the glass frit.

4. SiO in the ceramic color layer ２ / Bi ２ O ３ The vehicle glass according to any one of claims 1 to 3, wherein the mass ratio of

5. The vehicle glass according to any one of claims 1 to 4, wherein the ceramic color layer further comprises a filler.

6. 6. The vehicle glass according to claim 5, wherein the filler contains at least one selected from the group consisting of cordierite, zircon, and silica.

7. The thickness of the ceramic color layer is less than 15 μm, After a humidity resistance test in which the ceramic color layer was left standing for 500 hours under conditions of 80° C. and 96% RH, the outermost surface of the ceramic color layer was ２ O.K. ２ O and Bi ２ O ３ The content of {(Na ２ O+K ２ O) / Bi ２ O ３ 7. The vehicle glass according to claim 1, wherein the relationship of .lamda.<0.20 is satisfied.

8. The thermal expansion coefficient of the ceramic color layer at 50 to 350°C is 60 x 10 －７ ~77 x 10 －７ The vehicle glass according to any one of claims 1 to 7, wherein the temperature is 100°C.

9. The vehicle glass according to any one of claims 1 to 8, wherein the softening point Ts of the glass frit is 500 to 580°C.

10. The vehicle glass according to any one of claims 1 to 9, wherein the 0.1% breakage strength in a Weibull plot of static load strength is 20 MPa or more.

11. 11. The vehicle glass according to claim 10, wherein a terminal is joined via the lead-free solder layer, and after a humidity resistance test in which the terminal is subjected to an elapsed time of 500 hours under conditions of 80°C and a humidity of 96% RH, the peel strength of the terminal is 100 N or more.

12. The vehicle glass according to any one of claims 1 to 11, wherein the lead-free solder layer contains 95 mass% or more of Sn.

13. The vehicle glass according to any one of claims 1 to 12, wherein the lead-free solder layer is formed via a halogen-free flux.

14. The ceramic color layer is, in terms of mass % on an oxide basis, Yes ２ 15-30%, Yes ２ Oh ３ 30-55%, B ２ O ３ 0~4%、 Al ２ O ３ 1~4%、 Li ２ O 0~3%、 Na ２ O+K ２ O 0~1.8%、 MgO+CaO+BaO+SrO 1-10%, ZnO 0-10%, TO ２ 0~5%, CeO ２ 0~1%、 ZrO ２ 0-2%, and CuO+CrO+MnO+NiO+CoO 10-20% Contains The content of each ingredient is Na ２ O+K ２ O+B ２ O ３ 0.1~4.0% B ２ O ３ / Bi ２ O ３ 0 to 0.08, and SiO ２ / Bi ２ O ３ 0.3~1.0 The vehicle glass according to any one of claims 1 to 13, which satisfies the following relationship:

15. The vehicle glass according to any one of claims 1 to 14, which is used as a laminated glass for a windshield.

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