Conductive paste and glass article

Abstract

Provided are: an electrically conductive paste that, even if applied to a ceramic layer and sintered, can suppress sintering shrinkage and can suppress decreases in specific resistance after sintering; and a glass article in which this electrically conductive paste is used.　This electrically conductive paste is for forming an electrical conduction pattern on a ceramic layer that includes a glass constituent, wherein: at least an electrically conductive powder, a glass frit, an organic vehicle, and a sintering retardant are included; the sintering retardant is a silicon resinate; and the silicon resinate content relative to 100 wt% of the electrically conductive powder is at least 0.005 wt% by metal conversion. Moreover, an anti-fogging glass 10, as this glass article, comprises a glass substrate 12, a ceramic layer 14 formed on a surface of the glass substrate 12, and a conductor circuit that includes an electrically conductive film 20 formed on a surface of the ceramic layer 14, the electrically conductive film 20 being formed using this electrically conductive paste.

Description

[Technical Field]

[0001] The present invention relates to a conductive paste and a glass article, and more particularly to a conductive paste for forming an anti-fogging heating wire or antenna pattern attached to a window glass of a vehicle such as an automobile, and to a glass article such as an anti-fogging glass or a glass antenna that uses this conductive paste. [Background technology]

[0002] Glass articles such as anti-fogging glass equipped with anti-fogging heating wires and glass equipped with an antenna for receiving radio waves from outside the vehicle have been used in window glass for automobiles and other vehicles. These glass articles, such as anti-fogging glass, are typically formed by applying a conductive paste in lines onto a glass substrate as a raw material and firing the applied paste to form a conductive film with a predetermined pattern. Various types of conductive pastes of this type have been developed and proposed.

[0003] For example, Patent Document 1 discloses a conductive paste containing glass frit, a paste-forming medium, silver conductive particles, and non-precious metal-containing particles for producing a conductive coating on glass, ceramics, or enameled steel, a method for producing the coating, and an article coated with the coating. The conductive paste disclosed in Patent Document 1 relates to the field of conductive coatings fired onto substrates, where window glass and ceramic substrates are provided with conductor tracks for electrical and electronic purposes.

[0004] The conductive paste disclosed in Patent Document 1 contains non-precious metal-containing conductive particles that account for up to 80% by weight of the total conductive particles, and is substantially composed of iron, cobalt, nickel, copper, zinc, or an alloy containing at least one of these elements, particularly nickel, and has an average particle size d 50 is in the range of 0.1 to 15 μm, and the specific surface area is 0.5 to 10 m 2 / g range. The glass frit begins to soften at 350°C to 600°C and has a hemisphere temperature of 450°C to 700°C. By using such a conductive paste, the resistivity of a conductive coating on glass fired using fast firing at a temperature in the range of 660°C to 680°C varies by less than 10%, preferably less than 5%. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2004-525490 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when an electrode is formed by placing a conductive paste as proposed in Patent Document 1 on an amorphous ceramic layer, there is a problem that sintering shrinkage of silver occurs and cracks occur in the ceramic layer.

[0007] Furthermore, conductive pastes used to form anti-fogging heating wires and antenna patterns attached to window glass for vehicles such as automobiles have had the challenge of suppressing cracks in the ceramic layer to which they are applied, as well as suppressing a decrease in resistivity even in thin conductive patterns.

[0008] Therefore, the main object of the present invention is to provide a conductive paste that can suppress sintering shrinkage even when applied to a ceramic layer and sintered, and can suppress a decrease in resistivity after sintering, and a glass article using this conductive paste. [Means for solving the problem]

[0009] The conductive paste according to the present invention comprises: It is used to form an anti-fogging heating wire or antenna pattern attached to a vehicle window glass, and is formed on the surface of a glass substrate.A conductive paste for forming a conductive pattern on a ceramic layer containing a glass component, the conductive paste containing at least a conductive powder, a glass frit, an organic vehicle, and a sintering retarder, the sintering retarder being silicon resinate, the silicon resinate content being 0.02 wt% or more and 0.2 wt% or less in terms of metal relative to 100 wt% of the conductive powder, and the glass frit having a softening point of 350°C or more and 600°C or less.

[0010] The conductive paste according to the present invention contains a predetermined amount of silicon resinate as a sintering retarder, so that the silicon component is adsorbed to the conductive powder and inhibits the sintering of the conductive powder. As the sintering process progresses, the adsorbed silicon component generates silicon oxide. Furthermore, as the sintering process progresses, the glass frit contained in the conductive paste melts and flows, dissolving the silicon oxide and promoting the sintering of the conductive powder. As a result, it is possible to delay the timing of the sintering of the conductive powder. Furthermore, the conductive paste of the present invention contains a predetermined amount of silicon resinate as a sintering retarder, so that when silicon oxide is dissolved in the glass frit, the sintering of the conductive powder is not inhibited. As a result, the film density of the conductive film formed from the conductive paste increases with sintering, and as a result, the resistivity can be sufficiently reduced.

[0011] A glass article according to the present invention comprises a glass substrate, a ceramic layer formed on the surface of the glass substrate, and a conductor circuit including a conductive film formed on the surface of the ceramic layer, wherein the conductive film is formed by firing the conductive paste according to the present invention.

[0012] In the glass article according to the present invention, the sintering of the conductive powder contained in the conductive paste used to form the conductive film is delayed, so that the glass frit can flow sufficiently into the underlying ceramic layer before the conductive powder shrinks during sintering, thereby strengthening the bonding strength with the ceramic layer, which allows the ceramic layer to withstand the stress associated with the sintering shrinkage of the conductive powder and suppresses the occurrence of cracks in the ceramic layer. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a conductive paste that can suppress sintering shrinkage even when applied to a ceramic layer and sintered, and can also suppress a decrease in resistivity after sintering, and a glass article using this conductive paste.

[0014] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention, which proceeds with reference to the accompanying drawings. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a front view showing an embodiment of anti-fogging glass as a glass article manufactured using the conductive paste according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] Next, an embodiment of the present invention will be described in detail.

[0017] FIG. 1 is a front view showing one embodiment of anti-fogging glass as a glass article manufactured using the conductive paste according to the present invention, and FIG. 2 is a cross-sectional view taken along line II-II in FIG.

[0018] 1.Anti-fogging glass As shown in Figures 1 and 2, this anti-fogging glass 10 has a ceramic layer 14 formed on the surface of a glass substrate 12, and a conductive film 20 formed in a predetermined pattern on the surface of the ceramic layer 14. A plurality of thin, linear conductive films 20 are formed in parallel at predetermined intervals on the surface of the ceramic layer 14. Busbar electrodes 30a, 30b are formed on both ends of the conductive film 20, and the busbar electrodes 30a, 30b are connected to power supply terminals (not shown) via solder. In this way, the anti-fogging glass 10 comprises a conductor circuit made up of the conductive film 20 formed on the surface of the ceramic layer 14 and the busbar electrodes 30a, 30b.

[0019] 2. Anti-fogging glass manufacturing method The anti-fogging glass 10 can be manufactured as follows.

[0020] First, a ceramic paste containing ceramic powder including glass frit and an organic vehicle is prepared.

[0021] Here, the ceramic powder containing glass frit is not particularly limited, and can be appropriately selected from ZnO, Al2O3, BO, SiO2, TiO2, ZrO2, alkali metal oxides, alkaline earth metal oxides, etc. as needed, and mixed to a predetermined composition for use.

[0022] The glass frit is preferably amorphous. Amorphous glass frit is easily softened during firing and has good fluidity, so that it can be fired at a relatively low temperature.

[0023] Moreover, since the anti-fogging glass 10 is usually installed in the rear of a vehicle, it is preferable to add a black pigment having an anti-glare effect to the ceramic paste.

[0024] The organic vehicle may be the same as that used in the conductive paste of the present invention, which will be described later.

[0025] Then, the ceramic powder containing the glass frit and the organic vehicle are weighed and mixed to a predetermined mixing ratio, and the mixture is dispersed and kneaded using a three-roll mill or the like to produce a ceramic paste.

[0026] Next, this ceramic paste is applied onto a glass substrate 12 and dried, thereby forming a ceramic dry film. Next, the conductive paste of the present invention, which will be described later, is applied in lines onto the dried ceramic film and dried, and then a firing process is carried out to turn the dried ceramic film into a ceramic layer 14, and a conductive film 20 having a predetermined pattern is formed on the surface of the ceramic layer 14. As a result, the conductive film 20 is fixed onto the ceramic layer 14.

[0027] Thereafter, bus bar electrodes 30a, 30b are electrically connected to both ends of the conductive film 20, and the bus bar electrodes 30a, 30b are soldered to power supply terminals (not shown), thereby producing the anti-fogging glass 10 of this embodiment.

[0028] The anti-fogging glass thus formed is installed as, for example, the windshield or rear glass of a vehicle such as an automobile, and can perform the functions of preventing fogging of the window glass and functioning as an antenna by supplying power from the power supply terminals to the conductive film 20 via the bus bar electrodes 30a, 30b and generating heat. Furthermore, if the ceramic layer 14 is black, it has an anti-glare function.

[0029] 3.Conductive paste Next, the conductive paste for forming the conductive film 20 will be described in detail.

[0030] The conductive paste according to the present invention contains a conductive powder, a glass frit, an organic vehicle, and a sintering retarder.

[0031] The conductive powder that can be used in the conductive paste of the present invention is preferably a metal powder with good conductivity, such as silver (Ag), Ag alloy, palladium (Pd), silver-palladium alloy, copper (Cu), or Cu alloy. Among these, Ag powder is particularly preferred because it maintains good conductivity without being oxidized even when fired in air. Alternatively, the paste may contain 80 wt% or more Ag powder and various metal powders, such as Pd, Pt, Cu, or Ni, as additives.

[0032] The content of the conductive powder in the conductive paste is not particularly limited, but is preferably 50.0 wt% or more and 95.0 wt% or less. If the content of the conductive powder is less than 50.0 wt%, the content of the organic vehicle increases relatively, which may result in a thinner conductive film 20 and higher electrical resistance. Furthermore, solder erosion may occur easily during soldering, potentially reducing the bonding strength with the power supply terminal. On the other hand, if the content of the conductive powder exceeds 95.0 wt%, the conductive powder may become excessive, making it difficult to form a paste. Thus, the content of the conductive powder is preferably 50.0 wt% or more and 95.0 wt% or less, taking into account the ability to form a conductive paste and low line resistance.

[0033] The shape of the conductive powder is not particularly limited either, and may be, for example, spherical, flat, irregular, or a mixture of these.

[0034] Average particle size of conductive powder D 50 Although there is no particular limitation on the average particle diameter D 50 The average particle size D of the conductive powder is preferably 0.05 μm or more and 10 μm or less in terms of spherical powder. 50 However, if the particle size is less than 0.05 μm, it becomes difficult to make a paste. 50 If the thickness exceeds 10 μm, the electrical resistance tends to increase.

[0035] The conductive paste according to the present invention contains glass frit to bond the ceramic layer 14 and the conductive film 20 together.

[0036] The glass material used for the glass frit is not particularly limited, but from the viewpoint of promoting the adsorption of specific metal elements to the glass frit, it is preferable that it contains B or Bi, and it is preferable to use, for example, a Bi-B-Si-O based or Bi-B-Al-Si-O based glass frit.

[0037] Furthermore, the glass frit needs to be melted and flowable at the firing temperature to avoid a decrease in sintered density and insufficient sealing at the interface with the conductive film 20. Since glass articles such as the anti-fogging glass 10 are typically fired at a temperature of about 500°C or higher and 800°C or lower, it is preferable to use glass frit whose composition is adjusted so that its softening point is about 350°C or higher and 600°C or lower. Here, the "softening point" refers to the softening point obtained by the fiber elongation method of ASTM C338-57.

[0038] In the present invention, various oxides such as Zn, Ti, Zr, Cu, Fe, Sb, P, Te, Mg, Ca, Sr, Ba, Li, Na, K, and F may be contained in the above-mentioned Bi-B-Si-O-based, Bi-B-Al-Si-O-based, or other glass frits, as needed.

[0039] In addition, the average particle size of the glass frit D 50 The (median diameter) is not particularly limited, but is preferably 0.1 μm or more and 5.0 μm or less from the viewpoint of adhesion between the ceramic layer 14 and the conductive film 20 and sinterability of the conductive paste.

[0040] The organic vehicle is prepared so that the volume ratio of the binder resin to the organic solvent is, for example, 1 to 3:7 to 9. The binder resin is not particularly limited, and examples that can be used include ethyl cellulose resin, nitrocellulose resin, acrylic resin, alkyd resin, butyral resin, polyvinyl alcohol resin, polyester resin, epoxy resin, urethane resin, vinyl resin, amide resin, phenolic resin, and combinations thereof. The organic solvent is also not particularly limited, and examples thereof include α-terpineol, dihydroterpineol, hydrogenated terpineol acetate, texanol, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monohexyl ether, diethylene glycol monobenzyl ether, diethylene glycol dibutyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, triethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monobenzyl ether, and the like, which may be used alone or in combination.

[0041] Silicon resinate is used as the sintering retarder. The content of silicon resinate is 0.005 wt% or more relative to 100 wt% of the conductive powder. More preferably, it is 0.5 wt% or less. Within this range, the occurrence of cracks in the ceramic layer 14 can be suppressed and the resistivity can be reduced. Even more preferably, it is 0.02 wt% or more and 0.2 wt% or less. Within this range, the occurrence of cracks in the ceramic layer 14 can be further suppressed and the resistivity can be further reduced.

[0042] In addition to the conductive powder, glass frit, organic vehicle, and sintering retarder, the conductive paste of the present invention may contain additives containing specific metal elements to adjust the electrode properties as needed. It may also contain various additives, such as dispersants, plasticizers, anti-settling agents, and thixotropic agents, to adjust the properties of the conductive paste. The composition of the additives is not particularly limited, but the content is preferably 5 wt% or less of the total paste amount.

[0043] The conductive paste comprises a conductive powder, Bi-B- It can be easily produced by weighing and mixing Si-O type glass frit, organic vehicle, and sintering retarder in a predetermined ratio, and dispersing and kneading them using a three-roll mill or the like.

[0044] If silicon resinate is not added to the conductive paste, the glass frit melts after the Ag particles, which are the conductive powder, begin to sinter. This causes the Ag particles to shrink during sintering before the glass frit can bond them to the underlying ceramic layer, resulting in cracks in the ceramic layer. On the other hand, the conductive paste according to the present invention contains a predetermined amount of silicon resinate as a sintering retarder, so that the silicon component adsorbs to the Ag particles and inhibits the sintering of the Ag particles. As the sintering process progresses, the adsorbed silicon component generates silicon oxide. Furthermore, as the sintering process progresses, the glass frit contained in the conductive paste melts and flows, dissolving the silicon oxide and promoting the sintering of the Ag particles. As a result, it is possible to delay the timing of the sintering of the Ag particles. In this way, the delay in sintering of the Ag particles allows the glass frit to flow sufficiently into the underlying ceramic layer 14 before the Ag particles shrink during sintering, thereby strengthening the bonding strength with the ceramic layer 14. This allows the ceramic layer 14 to withstand the stress associated with the sintering shrinkage of the Ag particles, and the occurrence of cracks in the ceramic layer 14 can be suppressed.

[0045] Furthermore, the conductive paste of the present invention contains a predetermined amount of silicon resinate as a sintering retarder, so that when silicon oxide is dissolved in the glass frit, the sintering of the Ag particles is not inhibited. As a result, the film density of the conductive film 20 formed from the conductive paste increases with sintering, and as a result, the resistivity can be sufficiently reduced.

[0046] Furthermore, in the above embodiment, anti-fogging glass 10 is used as an example of a glass article, but the present invention can be widely used for various glass articles other than anti-fogging glass 10, such as glass antennas and other glass articles that require sulfur resistance.

[0047] 4. Experimental Example Next, experimental examples of the present invention will be specifically described.

[0048] A. Sample Preparation As the conductive metal, Ag powder was prepared, with an average particle size of 1 μm.

[0049] As the glass frit, Bi-B-Si-O based glass frit was prepared, and the average particle size of the prepared Bi-B-Si-O based glass frit was set to 2 μm.

[0050] Next, an organic vehicle was prepared by mixing ethyl cellulose resin and Texanol so that the binder resin was 10 wt % and the organic solvent was 90 wt %.

[0051] As resinate species further added as sintering retarders, samples containing silicon resinate (Si resinate) and samples containing various types of Rh resinate, Ni resinate, and Cu resinate were prepared.

[0052] The conductive paste for sample number 1 was prepared by compounding 80 wt% Ag powder, 4 wt% glass frit, and 16 wt% organic vehicle in a planetary mixer, and then dispersing and kneading the mixture in a three-roll mill to prepare a conductive paste sample.

[0053] The conductive pastes of sample numbers 2 to 9 were made of 80 wt% Ag powder, 4 wt% glass frit, and silicon resinate with a 10% Si content, with the Si content varying between 0.001 and 0.5 parts by weight per 100 parts by weight of Ag, with the remainder being an organic vehicle. These blends were then mixed in a planetary mixer and dispersed and kneaded in a three-roll mill to produce conductive paste samples.

[0054] The conductive paste for sample number 10 was made up of 80 wt% Ag powder, 4 wt% glass frit, and 0.1 parts by weight of Rh resinate with a 5% Rh content per 100 parts by weight of Ag, with the remainder being an organic vehicle. The resulting mixture was mixed in a planetary mixer and then dispersed and kneaded in a three-roll mill to produce a conductive paste sample.

[0055] The conductive paste for sample number 11 was made up of 80 wt% Ag powder, 4 wt% glass frit, and 0.1 parts by weight of Ni resinate with a 10% Ni content per 100 parts by weight of Ag, with the remainder being an organic vehicle. The resulting mixture was mixed in a planetary mixer and then dispersed and kneaded in a three-roll mill to produce a conductive paste sample.

[0056] The conductive paste for sample number 12 was made up of 80 wt% Ag powder, 4 wt% glass frit, and 0.1 parts by weight of Cu resinate with an 8% Cu content per 100 parts by weight of Ag, with the remainder being an organic vehicle. The resulting mixture was mixed in a planetary mixer and then dispersed and kneaded in a three-roll mill to produce a conductive paste sample.

[0057] B. Sample Evaluation (a) Evaluation by resistivity A soda-lime glass slide measuring 76.0 mm in length, 26.0 mm in width, and 1.4 mm in thickness was prepared. Using the conductive pastes corresponding to samples 1 to 12, a conductive pattern measuring 100 mm in length (L) and 0.5 mm in width (W) was printed onto the glass slide. The glass slide was then dried at 150°C for 10 minutes and then baked at a maximum baking temperature of 600°C for approximately 5 minutes to produce samples with conductive films corresponding to samples 1 to 12.

[0058] The line resistance value R (Ω) of the conductive film was measured using a micro-ohmmeter (Agilent Technologies, model number: 34420A), and the cross-sectional area A (μm 2 ) was measured using a surface roughness meter (Tokyo Seimitsu Kogyo Co., Ltd., model number: Surfcom1400D), and calculated using the line length L (mm) according to the following formula. Specific resistance (μΩ cm)=R×A / L / 10 Here, resistivity less than 2.8 μΩ·cm was judged as "◎", 2.8 μΩ·cm or more but less than 3.0 μΩ·cm was judged as "○", 3.0 μΩ·cm or more but less than 3.5 μΩ·cm was judged as "△", and 3.5 μΩ·cm or more was judged as "×".

[0059] (b) Crack evaluation A soda-lime glass slide measuring 76.0 mm in length, 26.0 mm in width, and 1.4 mm in thickness was prepared, along with black ceramic paste. The black ceramic paste was then screen-printed onto the glass slide and dried at 150°C for 10 minutes to produce a dried ceramic film (ceramic layer). Next, conductive patterns with a line length L of 100 mm and width W of 0.5 mm were printed on the black ceramic layer using the conductive pastes of Samples No. 1 to No. 12. The slide glasses were then dried at 150°C for 10 minutes and then fired at a maximum firing temperature of 650°C for approximately 5 minutes, producing samples with conductive films formed thereon, Samples No. 1 to No. 12. The peripheral edge of the conductive film on the black ceramic layer was observed under a microscope to check for the presence of cracks in the black ceramic layer. The presence of cracks was confirmed by irradiating light from the Ag electrode side to the glass substrate side and observing the transmitted light. Here, the case where there was no crack was judged as "A", the case where there was a slight crack was judged as "O", and the case where there was a crack was judged as "X".

[0060] Table 1 shows the resinate type, the amount of each resinate added, the resistivity, the presence or absence of cracks, and the overall evaluation results for Sample Nos. 1 to 12.

[0061] [Table 1]

[0062] C. Experimental Results In the sample No. 1, the resistivity was good, but since it did not contain silicon resinate, which is a sintering retardant, cracks occurred in the black ceramic layer.

[0063] In sample No. 2, the resistivity was good and the same as that of sample No. 1, but because the content of the sintering retarder silicon resinate was 0.001 wt%, sintering retardation did not occur and cracks occurred in the black ceramic layer.

[0064] In sample No. 3, 0.005 wt% of silicon resinate, a sintering retarder, was added, which reduced cracking in the black ceramic layer. Furthermore, the resistivity was the same as that of sample No. 1, which had no sintering retarder added. This is presumably because the addition of 0.005 wt% of silicon resinate, a sintering retarder, retarded the sintering of Ag.

[0065] In sample No. 4, 0.010 wt% of silicon resinate, a sintering retarder, was added, which reduced cracking in the black ceramic layer. Furthermore, the resistivity was the same as that of sample No. 1, which had no sintering retarder added. This is presumably because the addition of 0.010 wt% of silicon resinate, a sintering retarder, retarded the sintering of Ag.

[0066] In the samples Nos. 5 to 9, the amount of silicon resinate added as a sintering retarder was 0.02 wt % or more and 0.5 wt % or less, and therefore cracks in the black ceramic layer were further suppressed.

[0067] In samples No. 5 to No. 7, the amount of silicon resinate added as a sintering retarder was between 0.02 wt% and 0.1 wt%, so the resistivity was the same as that of sample No. 1, which had no sintering retarder added. On the other hand, in samples 8 and 9, the amount of silicon resinate added as a sintering retarder was 0.2 wt% and 0.5 wt%, respectively, so the resistivity tended to increase slightly. This is presumably because the sintering retardation effect of Ag becomes greater as the amount of silicon resinate added increases. Furthermore, if the amount of silicon resinate added as a sintering retarder is 0.2 wt% or more, the amount of silicon oxide, which is an insulator, increases, and it is presumed that conductivity decreases.

[0068] In sample No. 10, the addition of Rh resinate suppressed cracking in the black ceramic layer, but a significant increase in resistivity was observed. This is presumably because the addition of Rh resinate suppressed the sintering of Ag, which in turn suppressed the shrinkage that accompanies sintering, thereby reducing stress on the underlying black ceramic layer and thus suppressing cracking. On the other hand, it was confirmed that the suppression of sintering reduced film density, resulting in a decrease in conductivity.

[0069] Sample No. 11 contained Ni resinate, and sample No. 12 contained Cu resinate, so cracks occurred similarly to those observed in sample No. 1, where no sintering retardant was added. In both samples, the sintering-suppressing effect of Ag was confirmed, but it is presumed that the sintering shrinkage of Ag began before the glass frit melted, which meant that cracks in the black ceramic layer could not be suppressed.

[0070] The above experimental results show that when the conductive paste according to the present invention contains a predetermined amount of silicon resinate as a sintering retarder, the silicon component adsorbs to the Ag particles, inhibiting the sintering of the Ag particles. As the sintering process progresses, the adsorbed silicon component generates silicon oxide. Furthermore, as the sintering process progresses, the glass frit contained in the conductive paste melts and flows, dissolving the silicon oxide and promoting the sintering of the Ag particles. As a result, it is possible to delay the timing of the sintering of the Ag particles. In this way, it was revealed that delaying the sintering of the Ag particles allows the glass frit to flow sufficiently into the underlying black ceramic layer before the Ag particles shrink during sintering, strengthening the bonding force with the black ceramic layer, allowing the black ceramic layer to withstand the stress associated with the sintering shrinkage of the Ag particles and suppressing the occurrence of cracks in the black ceramic layer. Furthermore, it has been revealed that when the conductive paste of the present invention contains a predetermined amount of silicon resinate as a sintering retarder, silicon oxide is dissolved in the glass frit and the sintering of Ag particles is not inhibited, and therefore the film density of the conductive film formed from the conductive paste increases with sintering, thereby enabling the resistivity to be sufficiently reduced. [Explanation of symbols]

[0071] 10 Anti-fog glass 12 Glass substrate 14 ceramic layer 20 Conductive film 30a, 30b busbar electrodes

Claims

1. A conductive paste used to form an anti-fogging heating wire or antenna pattern attached to a vehicle window glass, the conductive paste forming a conductive pattern on a ceramic layer containing a glass component formed on the surface of a glass substrate, Contains at least a conductive powder, a glass frit, an organic vehicle, and a sintering retarder; the sintering retarder is a silicon resinate; The content of the silicon resinate is 0.02 wt % or more and 0.2 wt % or less in terms of metal with respect to 100 wt % of the conductive powder, The conductive paste is characterized in that the glass frit has a softening point of 350°C or higher and 600°C or lower.

2. 2. The conductive paste according to claim 1, wherein the glass frit is a Bi-B-Si-O system or a Bi-B-Al-Si-O system.

3. A glass substrate; a ceramic layer formed on the surface of the glass substrate; a conductor circuit including a conductive film formed on the surface of the ceramic layer, The conductive film is formed by firing the conductive paste according to claim 1 or 2. A glass article formed by this.

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