CN1690852A - Glass composition for silver paste, photosensitive silver paste using same, electrode pattern and plasma display panel - Google Patents

Abstract

The present invention researches out an electric conductive slurry used glass composition which can do restraint to the inducing of the suppressor electrode in the state that the composition is used for high-precision electric conductor, with the using of the photosensitive silver slurry of the glass composition the high-precision electric conductor pattern which has excellent long-term reliability because of the low mobility can be provided. The present invention relates to a silver slurry used glass composition and the photosensitive silver slurry containing the glass composition, wherein the glass composition uses boron and silicon dioxide as the compulsory component, and the content of boron is less than or equal to 10wt 1n the glass composition when conversed with B2O3, when conversed with oxide the composition ratio satisfies the formula (I) or (II): B2O3 wt<=SiO2 wt(I) B2O3 wtnOwt<=SiO2 wt(II).

Description

Glass composition for silver paste, photosensitive silver paste using same, electrode pattern and plasma display panel

technical field

The invention relates to a glass composition for silver paste and a photosensitive silver paste using the glass composition, in particular to a glass composition for silver paste suitable as an electrode material and a glass composition using the glass composition. Photosensitive silver paste, in which the electrode material is obtained by firing a graphic coating film formed by screen printing or photolithography.

Background technique

Conventionally, electrodes on non-alkaline glass and other various glass substrates have been formed by vapor deposition in components such as plasma display panels, CCD sensors, and image sensors. However, this vapor deposition method deposits the electrode forming material in a vacuum container and deposits the metal film, which has the disadvantages of large equipment, high cost, troublesome parts in and out, and poor operability, such as time required for vacuum introduction. In addition, it is difficult to increase the thickness of the electrode by the vapor deposition method, and it is not suitable for the low resistance of the circuit.

Correspondingly, as other methods of forming an electrode pattern layer on a substrate, printing techniques such as screen printing have been proposed to mix conductive powder into a non-photosensitive organic binder to form a paste, such as a dry type and A method of patterning a thermosetting conductive paste on a substrate, and a method of forming a conductor pattern with a photosensitive conductive paste by photolithography (for example, refer to Patent Documents 1 and 2). The advantage of this technique is that it can form conductor patterns without going through complicated steps. However, when it is used to form high-precision patterns with small gaps between electrode lines, migration is induced and long-term reliability cannot be obtained.

Patent Document 1: Japanese Unexamined Patent Publication No. H10-269848

Patent Document 2: Japanese Unexamined Patent Publication No. 11-224531

Contents of the invention

The problem to be solved by the present invention

The present invention has been developed in view of the above-mentioned problems of the prior art, and its main purpose is to develop a glass composition for conductive paste that can suppress induction of electrode migration even when used in a high-precision conductor pattern, By using the photosensitive silver paste using this glass composition, it is possible to provide a highly accurate conductor pattern with low mobility and excellent long-term reliability.

The solution to this problem

The inventors of the present invention conducted intensive studies to achieve the above objects, and found that the induction of migration of high-precision patterns formed with conductive paste has an important relationship with the composition of low-melting glass frit contained in the conductive paste. Furthermore, by limiting the composition ratio within a specific range, it was found that a conductor pattern with low mobility conductivity and excellent high-precision pattern formability can be easily obtained without going through complicated steps, and thus completed the present invention.

That is, according to the present invention, there is provided a glass composition for silver paste, which composition contains boron and silicon dioxide as essential components, and the content of boron in the glass composition in terms of B ₂ O ₃ is less than or equal to 10 wt. %, characterized in that: its composition ratio satisfies the following formula (I) or (II) in terms of oxides

B ₂ O ₃ wt% ≤ SiO ₂ wt% (I)

B ₂ O ₃ % by weight + ZnO by weight ≦ SiO ₂ % by weight (II).

In one embodiment of the present invention, the ZnO content in the glass composition for silver paste is preferably less than or equal to 12% by weight.

In one embodiment of the present invention, the SiO ₂ content in the glass composition for silver paste is preferably 8-30% by weight.

And, according to the present invention, a kind of photosensitive silver paste is provided, and this silver paste contains silver powder, photosensitive organic component and above-mentioned glass composition, wherein relative to the silver powder of 100 weight parts, the content of this glass composition is 2-15 weight parts within the range of parts.

In addition, according to the present invention, an electrode pattern is provided, which is formed by firing the aforementioned photosensitive silver paste.

Also, according to the present invention, there is provided a plasma display panel using the aforementioned photosensitive silver paste to form electrodes.

Invention effect

According to the present invention, it is also possible to provide a photosensitive silver paste excellent in migration characteristics (migration suppression effect) when used for high-precision electrode patterns. Therefore, the silver paste of the present invention can be effectively used for plasma displays.

Detailed ways

As a conductive paste for electrodes formed on a glass substrate, in order to obtain excellent conductivity by firing at a temperature below 620°C in an air environment, the selection of conductive powder is very important, and the commonly used noble metals are not easily susceptible Oxidation affects the price of cheaper silver powder. By using the screen printing method and the photolithography method, although it is possible to form a pattern like a line/space = 40/40 (μm), there is a problem that the silver paste used in such a high-precision pattern will migrate, so there is a problem. High precision limit as mentioned above.

The low-melting-point glass powder used in the silver paste, known its softening point (hereinafter referred to as "SP" value) and the amount added have a very large impact on the adhesion and resistance value of conductive pastes such as silver paste, the present invention et al. conducted in-depth research on low-melting point glass powder from the perspective of low migration, and as a result, it was confirmed that the following three components have a great influence on the suppression of migration. That is, increasing the composition ratio (parts by weight) of SiO ₂ can effectively suppress the migration, while increasing the composition ratio of B ₂ O ₃ and ZnO makes the migration significantly worse. Furthermore, the inventors of the present invention have found that the migration characteristics are the best when the composition ratio of these components is satisfied by measuring the composition ratio of these components, and thus completed the present invention.

B ₂ O ₃ wt% ≤ SiO ₂ wt% (I)

B ₂ O _3wt %+ZnOwt%≤SiO _2wt % (II)

Among them, B ₂ O ₃ is less than or equal to 10% by weight.

The glass composition for silver paste of the present invention, the photosensitive silver paste using the glass composition, and the electrode pattern are described in detail below.

The glass composition for silver paste of the present invention contains boron and silicon dioxide as essential components, and its composition ratio satisfies the following formula (I) or (II) in terms of oxides.

B ₂ O ₃ wt% ≤ SiO ₂ wt% (I)

B ₂ O _3wt %+ZnOwt%≤SiO _2wt % (II)

The _SiO2 component has the effect of inhibiting the migration of silver paste, and its content is not particularly limited, as long as it satisfies the formula (I) or (II), it is preferably mixed in the range of 8-30% by weight. If it is less than 8% by weight, the migration characteristics will be lowered. On the other hand, if it exceeds 30% by weight, the softening point will be too high, for example, it may be difficult to sinter on a glass substrate at a temperature of 620° C. or lower.

B ₂ O ₃ and ZnO, which are components whose content is increased to deteriorate migration characteristics, must satisfy the formula (I) or (II).

In order to lower the softening point of the glass composition, B ₂ O ₃ is used as an essential component of the present invention. The preferable softening point of the glass composition of this invention is 400-590 degreeC, and it _is preferable to adjust the addition amount of _B2O3 in order to make a softening point fall in this range. However, since the reduction in migration characteristics is very large when the _B2O3 content exceeds 10% by weight, _its content cannot exceed 10% by weight. The preferred content of B ₂ O ₃ is 1-8% by weight, more preferably 2-6% by weight or less.

ZnO is not an essential component, but is a constituent element of the above-mentioned general formula (II), and when it is contained, this formula must be satisfied. Also, its content is desirably equal to or less than 12% by weight. The reason is that when the content exceeds 12% by weight, the glass becomes unstable due to crystallization, and also turns yellow when fired at a high temperature, and the migration characteristics decrease.

The above-mentioned glass composition of the present invention may be a lead-based or bismuth-based glass composition, and each is preferably mixed in a range of 40 to 90% by weight in terms of Pb ₂ O ₃ or Bi ₂ O ₃ . When it is less than 40% by weight, the bonding strength of the conductive film to the substrate is insufficient when the silver paste is sintered on the glass substrate. As a result, the sinterability of the conductor film is lowered, and the bonding strength with the substrate may be lowered. The glass composition of the present invention used as the material for silver paste has a preferred softening point of 400-590° C. from the viewpoint of the adhesion and resistance of the silver paste, and the silver powder in 100 parts by weight of the paste is less than the silver paste. Among them, the preferred mixing ratio is 2 to 15 parts by weight.

The glass composition of the present invention may also contain BaO and Al ₂ O ₃ . The preferred content is 0-20% by weight of BaO and 0-5% by weight of Al ₂ O ₃ , more preferably 0.5-2.5% by weight. If the content of BaO exceeds 20% by weight, the expansion coefficient of the glass composition is too large, so it is not preferred, and when the _Al2O3 content exceeds 5% by weight, the softening point of the glass composition becomes high, and the silver paste is formed on _the glass substrate. In the case of over-sintering, the adhesive strength of the conductor film to the substrate is insufficient, so it is not preferable.

Furthermore, the inventors of the present invention have found that, in addition to the above-mentioned components, alkali metal oxides such as Na ₂ O, Li ₂ O, and K ₂ O are also involved in inducing migration of high-precision patterns. It is therefore preferred that alkali metal oxides are absent from the glass composition of the invention, and where they are present, they are preferably contained in relatively low amounts. Moreover, since an alkaline component will react with the silver powder in a silver paste, and a glass substrate will turn yellow, it is preferable not to contain them also from a viewpoint of suppressing yellowing.

The powder particle size of the glass composition of the present invention is preferably less than 10 μm in average particle size measured using a laser diffraction scattering particle size distribution measuring device such as a micro track or a particle size distribution measuring device using a laser Doppler method from the viewpoint of clarity. , and either crystallinity or non-crystallinity is acceptable.

The glass composition of the present invention can suppress migration in high-precision electrode patterns formed by screen printing and photolithography when used together with silver powder as a material for silver paste and an organic component.

The organic component contains an organic binder that functions as a material that binds the components before firing and a material that imparts photocurability and developability to the composition. The organic binder may be photosensitive or non-photosensitive, and is a resin having a carboxyl group. Specifically, one of a carboxyl group-containing photosensitive resin having an ethylenically unsaturated double bond and a carboxyl group-containing resin not having an ethylenically unsaturated double bond can be used by itself. Examples of suitable resins (both oligomers and polymers) are listed below.

A carboxyl-containing resin obtained by copolymerization of (a) an unsaturated carboxylic acid and (b) a compound having an unsaturated double bond;

A carboxyl-containing photosensitive resin obtained by adding an ethylenically unsaturated group as a side group to a copolymer of (a) an unsaturated carboxylic acid and (b) a compound having an unsaturated double bond;

On the copolymer of (c) a compound having an epoxy group and an unsaturated double bond and (b) a compound having an unsaturated double bond, the (a') saturated or unsaturated carboxylic acid is reacted, and the resulting secondary hydroxyl The carboxyl-containing resin obtained by making (d) polybasic acid anhydride reaction;

On the copolymer of (e) an acid anhydride having an unsaturated double bond and (b) a compound having an unsaturated double bond, make (f) a carboxyl-containing resin obtained by reacting a compound having a hydroxyl group;

On the copolymer of (e) an acid anhydride having an unsaturated double bond and (b) a compound having an unsaturated double bond, the carboxyl-containing photosensitive resin obtained by reacting (f') a compound having a hydroxyl group and an unsaturated double bond;

Carboxyl group-containing photosensitive resin obtained by reacting (g) epoxy compound with (h) unsaturated monocarboxylic acid, and reacting (d) polybasic acid anhydride on the generated secondary hydroxyl group;

On the epoxy group of a copolymer of (b) a compound having an unsaturated double bond and glycidyl (meth)acrylate, react (i) an organic acid having a carboxyl group in one molecule and having no ethylenically unsaturated bond , make (d) polybasic acid anhydride reaction obtain carboxyl-containing resin on the secondary hydroxyl group that generates;

On the (j) hydroxyl-containing polymer, (d) polybasic acid anhydride is reacted to obtain carboxyl-containing resin;

On the (j) hydroxyl-containing polymer, (d) polybasic acid anhydride is reacted to obtain a carboxyl-containing resin, and on the carboxyl-containing resin, (c) is reacted with a compound having an epoxy group and an unsaturated double bond to obtain a carboxyl-containing photosensitive Sexual resin.

In addition, printing resins can also be used as organic components, such as cellulose resins such as nitrocellulose, ethyl cellulose, and hydroxyethyl cellulose; polybutyl acrylate, polymethacrylate, etc.; Acrylic resin; acrylic copolymer; polyvinyl alcohol; polyvinyl butyral, etc., which may be used alone or in combination of two or more.

The above-mentioned photosensitive organic components containing carboxyl group-containing photosensitive resins, and carboxyl group-containing resins or non-photosensitive organic components containing printing resins can be used alone or in combination, but in any case, the organic components containing them The binder may be mixed in a proportion of 5-50% by weight of the total composition. When the mixing amount of these resins is less than or equal to the above range, the distribution of the above resins in the formed coating film tends to be uneven, and it is difficult to obtain sufficient photocurability and photocurability depth, so it is difficult to pattern through selective exposure and development. On the other hand, if it exceeds the above range, pattern shrinkage and line width shrinkage tend to occur during firing, so it is not preferable.

Moreover, as the above-mentioned carboxyl group-containing photosensitive resin and carboxyl group-containing resin, resins each having a weight average molecular weight of 1,000-100,000, more preferably 5,000-70,000 and an acid value of 30-250 mgKOH/g can be suitably used, and the carboxyl group-containing In the case of a photosensitive resin, a resin having a double bond equivalent of 350-2000, more preferably 400-1500 can be suitably used. When the molecular weight of the resin is less than or equal to 1,000, the adhesion of the film during development is adversely affected. On the other hand, when it is higher than 100,000, poor development tends to occur, which is not preferable. In addition, when the acid value is less than or equal to 30 mgKOH/g, due to insufficient solubility in alkaline aqueous solution, poor development is likely to occur. On the other hand, when the acid value is higher than 250 mgKOH/g, poor adhesion of the film during development occurs. And since the photocured part (exposed part) melt|dissolves, it is not preferable. Moreover, when it is a carboxyl-containing photosensitive resin, when the double bond equivalent of the photosensitive resin is less than 350, residues tend to remain during firing; High exposure levels may be required for curing and are not preferred.

In the photosensitive silver paste formed by the glass composition, silver powder and photosensitive organic components according to the present invention, in order to promote the photocurability and developability of the composition, a photopolymerizable monomer may be included. Examples of the photopolymerizable monomer include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, polyurethane diacrylate ester, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, trimethylolpropane ethylene oxide modified triacrylate, trimethylolpropane propylene oxide modified triacrylate esters, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate and the respective methacrylates corresponding to the above acrylates; phthalic acid, adipic acid, maleic acid, itaconic acid, succinic acid, trimellitic acid Acids, polybasic acids such as terephthalic acid and mono-, di-, tri- or above polyesters of hydroxy (meth)acrylates, etc., but are not limited to these specific substances, and they can be used alone Or mix two or more. Among these photopolymerizable monomers, polyfunctional monomers having two or more acryloyl groups or methacryloyl groups in one molecule are preferable.

The mixing ratio of the photopolymerizable monomer is suitably 20 to 100 parts by weight relative to 100 parts by weight of the aforementioned organic binder. When the mixing amount of the photopolymerizable monomer is equal to or less than the above-mentioned range, it is difficult to obtain sufficient curability of the composition. On the other hand, when it exceeds the above-mentioned range, the surface layer part is prematurely photocured compared with the inside of the film, so it is easy to Produces cured stains.

The photosensitive silver paste of the present invention contains a photopolymerization initiator as a component for initiating a photoreaction. Specific examples of photopolymerization initiators that mainly absorb ultraviolet rays to generate free radicals include benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether. and benzoin alkyl ethers; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1 -Acetophenones such as dichloroacetophenone; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-di Methylamino-1-(4-morpholinophenyl)-butanone-1 and other aminoacetophenones; 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1 -Anthraquinones such as chloroanthraquinone; 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone, etc. Thioxanthones; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone; or xanthones; (2,6-dimethoxy Benzoyl)-2,4,4-pentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl di Phine oxides such as phenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphinate; various peroxides, etc., but are not limited to these specific substances, and they may be used alone Use or mix two or more.

The mixing ratio of these photopolymerization initiators in the slurry is suitably 1 to 30 parts by weight, preferably 5 to 20 parts by weight, relative to 100 parts by weight of the aforementioned organic binder. When it is less than the above range, it is difficult to obtain sufficient photocurability of the paste, and on the other hand, when it is greatly exceeded, it is difficult to obtain internal photocurability because light transmission is prevented.

Moreover, in the case where a deeper photocuring depth is required, if necessary, dinuclear titanocene (titanocene) photopolymerization initiators such as イルガキュュア 784 manufactured by Chiba Specialty Chemikarls Co., Ltd. that initiates radical polymerization in the visible region can be Agents, leuco dyes, etc. are used in combination as curing aids.

The silver powder contained in the photosensitive silver paste of the present invention is not affected by oxidation, and firing at 450-620° C. makes the paste have excellent conductivity, so it is the selected conductive powder in the present invention. As the particle shape, various shapes such as spherical shape, flake shape, and dendritic shape can be used, but spherical particles are particularly preferably used in view of optical characteristics and dispersibility. The average particle diameter of the silver powder may be 0.5-5.0 μm as measured by a laser diffraction scattering type particle size distribution measuring device such as a micro track or a particle size distribution measuring device using a laser Doppler method. When the average particle diameter is less than or equal to 0.1 μm, the light transmittance is poor and it is difficult to draw a high-precision pattern, so it is not preferable. On the other hand, when the average particle diameter exceeds 5 μm, it is difficult to obtain the linearity of the line edge, which is also not preferable. The specific surface area can be suitably used in the range of 0.1 to 2.0 m ² /g. When the specific surface area is less than 0.1 m ² /g, it is not preferable because problems such as sedimentation occur during storage. On the other hand, when the specific surface area exceeds 2.0 m ² /g, the oil absorption is large and the fluidity of the slurry is impaired, so it is also not preferable. .

The mixing ratio of the silver powder is suitably 45-90 parts by weight relative to 100 parts by weight of the photosensitive silver paste. When the mixing ratio of the conductive powder is less than or equal to the above range, sufficient conductivity cannot be obtained in the conductor pattern formed using this slurry. On the other hand, if it exceeds the above range, the adhesion to the base material is poor, so it is not preferable. of.

In addition, for the purpose of adjusting the color tone, black pigments composed of metal oxides or composite metal oxides containing one or more of Fe, Co, Cu, Cr, Mn, Al, Ru, and Ni as main components can be added. , cobalt tetroxide (Co ₃ O ₄ ), ruthenium oxide, lanthanum composite oxide and other black materials.

Furthermore, the photosensitive silver paste of the present invention may also be mixed with acidic compounds such as phosphoric acid, phosphoric acid ester, carboxylic acid-containing compounds, silicones, acrylics, and other defoaming and leveling agents for ensuring storage stability, if necessary. , Thixotropy imparting agent for adjusting fluidity, silane coupling agent and other additives for improving film adhesion. In addition, if necessary, known and commonly used oxidation inhibitors for preventing oxidation of conductive metal powder, thermal polymerization inhibitors for improving thermal stability during storage, and metals as bonding components to the substrate during firing may be added. Particles such as oxides, silicon oxides, boron oxides, and low-melting glass. Furthermore, inorganic powders such as silica, bismuth oxide, alumina, and titanium oxide, organometallic compounds, metal organic acid salts, metal alkoxides, and the like may be added for the purpose of adjusting firing shrinkage.

The photosensitive silver paste of the present invention is obtained by mixing the above-mentioned essential components and optional components in a certain ratio, and uniformly dispersing them through kneading machines such as three rolls and agitators. The photosensitive silver paste of the present invention thus obtained is formed on a substrate as a conductor pattern through the following steps, for example. Such a conductor pattern can be suitably used as an electrode pattern of a front substrate and/or a rear substrate of a plasma display panel.

(1) First, the photosensitive silver paste of the present invention is applied to a substrate, such as a plasma display panel (PDP), through suitable coating methods such as screen printing, bar coating, and knife coating. On the glass substrate of the front substrate, etc., in order to obtain finger-touch dryness, dry at about 60-120°C for about 5-40 minutes in a hot air circulation drying oven or a far-infrared drying oven, etc., and let the organic solvent Evaporation gave a tack-free film.

Here, the substrate is not particularly limited, but for example, heat-resistant substrates such as glass substrates and ceramic substrates can be used.

In addition, the slurry may be formed into a film in advance, and in this case, the film may be laminated on the substrate.

(2) Next, the dried coating film formed on the substrate is developed by pattern exposure. As the exposure step, contact exposure or non-contact exposure using a negative mask having a certain exposure pattern may be used. As the exposure light source, a halogen lamp, a high-pressure mercury lamp, a laser, a metal halide lamp, a black light lamp, an electrodeless lamp, or the like can be used. The exposure amount is preferably about 50-1000 mJ/cm ² .

A spray method, a dipping method, etc. are used for a developing process. As the developing solution, metal alkaline aqueous solution such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium silicate, and amine aqueous solution such as monoethanolamine, diethanolamine, triethanolamine are suitably used, especially about 1.5% by weight or less The dilute alkaline aqueous solution of concentration can also saponify the carboxyl group in the carboxyl group-containing resin in the composition to remove the uncured part (unexposed part), but it is not limited to the above-mentioned developing solution. Furthermore, in order to remove unnecessary developing solution after development, it is preferable to perform washing with water and acid neutralization.

(3) Next, after firing the pattern of the obtained photosensitive silver paste, the organic component contained in the paste is debindered to obtain a fixed conductor pattern.

Example

The present invention is described in detail below by examples, however, the present invention is not limited to the following examples. In addition, the following "parts" all mean parts by weight unless otherwise specified.

(Synthesis example of organic binder)

In a flask equipped with a thermometer, a stirrer, a dropping funnel and a reflux cooler, add the solvent diethylene glycol monoethyl ether acetate, the catalyst azobisisobutyronitrile, and heat to 80°C under a nitrogen atmosphere. Within 2 hours, a monomer mixture of methacrylic acid and methyl methacrylate in a molar ratio of 0.4 mol:0.6 mol was added dropwise, and after stirring for 1 hour, the temperature was raised to 115° C. to inactivate it to obtain a resin solution.

After cooling the resin solution, use the catalyst tetrabutylammonium bromide to add 0.4 mol of butyl glycidyl ether to the carboxyl group of the obtained resin under the condition of 95-105°C for 30 hours. ,cool down.

Moreover, the OH group of the obtained resin was subjected to an addition reaction with 0.26 mol of tetrahydrophthalic anhydride at 95-105° C. for 8 hours, and was taken out after cooling to obtain an organic compound with a solid content of 55%. Adhesive A.

(composition example 1-5, comparative combination example 1-4)

Using the organic binder A obtained as described above, it is mixed with the glass powder A shown in Table 1 at the composition ratio shown below, stirred with a mixer, and then ground with a 3-roll pulverizer to make a slurry to obtain a photosensitive permanent silver paste (composition example 1). Furthermore, glass powder A was replaced with 22-55 parts of glass powder B-H described in Table 1 to prepare composition examples 2-5 and comparative composition examples 1-4. Furthermore, the average particle diameters of these glass powders A-H were measured to be in the range of 1.2 to 3.4 μm using a laser diffraction scattering type particle size distribution measuring device: LMS-30 (manufactured by Seishin Co., Ltd.).

Table 1

(composition example 1)

Organic Adhesive A 180.0 parts

Trimethylolpropane triacrylate 45.0 parts

2-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1 10.0 parts

Isopropylthioxanthone 1.0 parts

Dipropylene glycol monomethyl ether 90.0 parts

Silver powder A ^* 550.0 parts

Glass powder A 38.5 parts

Phosphate 2.0 parts

Antifoaming agent (BYK-354: ビツクケミミー・Japan Co., Ltd.) 1.0 parts

^* The average particle size (measured by a laser diffraction scattering particle size distribution measuring device: Microtrac HRA): 2.0 μm, and the specific surface area (measured by BET 1-point method): 0.42 m ² /g were used.

Migration characteristics were evaluated by examining the insulation resistance value of the photosensitive electroconductive paste obtained in this way for Composition Examples 1-5 and Comparative Composition Examples 1-4, and whether dendrites were generated.

The evaluation method is as follows.

Production of experimental films:

On the glass substrate, each photosensitive silver paste for evaluation was fully coated with a 180-mesh polyester sieve, and then dried at 90°C for 20 minutes in a heat-sealing circulation drying oven to form a silver paste with good finger-drying properties. coating film. Then, using a metal halide lamp as a light source, pass through a negative mask so that the cumulative light intensity on the dry coating film is 300mJ/ ^cm2 After _pattern exposure, develop with a 0.5% by weight _Na2CO3 aqueous solution at a liquid temperature of 30°C , washed with water. Then, the substrate thus formed with the coating film pattern was heated up to 570° C. at 5° C./minute in the air environment, and fired at 570° C. for 30 minutes to prepare a test piece on which a conductor pattern was formed.

(insulation resistance value)

The comb-shaped pattern with L/S=120/80 μm was exposed, developed and imaged until fired, and the pattern was coated with a UV-curable moisture-proof agent, and then cured to prepare an evaluation sheet. After that, it was treated in a 65°C, 95% RH constant temperature and high humidity chamber for 144 hours while applying a direct current of 80V, and the insulation resistance value after the treatment was measured to evaluate the degradation of insulation. The insulation resistance value is a measured value after applying a voltage of 500V for 1 minute.

(dendritic evaluation)

With respect to the test piece subjected to insulation evaluation, it was confirmed whether or not silver branches were generated between the comb electrodes after the evaluation.

These evaluation results are shown in Table 2.

It can be seen from Table 2 that the silver paste of the present invention has excellent migration characteristics when used for high-precision conductor patterns.

Table 1 continued Glass powder A Glass powder B Glass powder C Glass powder D Glass powder E Glass powder F Glass powder G Glass powder H Bi ₂ O ₃ - 68 44 71 - 53 58 49 Pb ₂ O ₃ 70 - - - 60 - - - B ₂ O ₃ 1.5 5 5 5 20 5 15 15 ZnO - 6 11 4 - 18 11 4 SiO ₂ twenty three 13 20 12 15 12 4 12 BaO 4 6 20 5 - 12 12 20 Al ₂ O ₃ 1.5 2 - - 5 - - - SP(°C) 524 519 517 490 525 550 508 572

Table 2 Composition Example 1 Composition Example 2 Composition Example 3 Composition Example 4 Composition Example 5 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 glass powder A B C D. D. E. f G h Capacity of glass to silver powder (wt%) 7 7 7 4 10 7 7 7 7 Insulation resistance (Ω) 7.8× ^10-12 6.4× ^10-12 8.0×10 ^-12 5.6× ^10-12 8.3× ^10-12 3.6×10 ^-4 3.7×10 ^-4 2.0×10 ^-7 4.8×10 ^-7 Whether branching occurs no no no no no yes yes yes yes

Claims (10)

1. A glass composition _for silver paste, which contains boron and silicon dioxide as essential components, and the content of boron in the glass composition in terms of _B2O3 is less than or equal to 10% by weight, characterized in that: The composition ratio satisfies the following formula (I) in terms of oxides B ₂ O ₃ % by weight ≦ SiO ₂ % by weight (I). 2. A glass composition _for silver paste, which contains boron and silicon dioxide as essential components, and the content of boron in the glass composition in terms of _B2O3 is less than or equal to 10% by weight, characterized in that: The composition ratio satisfies the following formula (II) in terms of oxides B ₂ O ₃ % by weight + ZnO by weight ≦ SiO ₂ % by weight (II). 3. The glass composition for silver paste according to claim 2, characterized in that the ZnO content is less than or equal to 12% by weight. 4. The glass composition for silver paste according to any one of claims 1-3, characterized in that the content of SiO ₂ is 8-30% by weight. 5. A photosensitive silver paste, which contains silver powder, photosensitive organic components and the glass composition according to any one of claims 1-3, relative to 100 parts by weight of silver powder, the glass composition The content is in the range of 2-15 parts by weight. 6. A photosensitive silver paste, the photosensitive silver paste contains silver powder, photosensitive organic components and the glass composition according to claim 4, relative to 100 parts by weight of silver powder, the content of the glass composition is 2-15 within the range of parts by weight. 7. An electrode pattern, characterized in that it is composed of the pattern of fired photosensitive silver paste according to claim 5. 8. An electrode pattern, characterized in that it consists of the pattern of fired photosensitive silver paste according to claim 6. 9. A plasma display panel, characterized in that the photosensitive silver paste according to claim 5 is used to form electrodes. 10. A plasma display panel, characterized in that the photosensitive silver paste according to claim 6 is used to form electrodes.