KR20120089615A - Photosensitive conductive paste, and electrode and plasma display panel formed using the same - Google Patents

Abstract

PURPOSE: A photosensitive conductive paste, electrode and a plasma display panel which is formed by using the same are provided to reduce use amount of silver used as conductive powder and to form thin electrode having a ling shape. CONSTITUTION: A photosensitive conductive paste has the film thickness of the electrode which is formed by using the paste is 1.2 microns or less. The paste comprises an organic binder, silver powder having the tap density of 2.0-5.0 g/cm^3, the specific surface area of 1.5-2.0 m^2/g and the primary particle diameter of 1.0 micron or less, a photo-polymerizable monomer, a photo-polymerizable initiator, an organic solvent, and a glass frit. The mixing amount of the glass frit is 1-30 mass unit based on 100.0 mass unit of Ag powder. The mixing amount of the silver powder is 30-45 mass unit based on 100.0 mass unit of photosensitive conductive paste.

Description

PHOTOSENSITIVE CONDUCTIVE PASTE, AND ELECTRODE AND PLASMA DISPLAY PANEL FORMED USING THE SAME}

The present invention is, for example, to a method of manufacturing a photosensitive conductive paste, an electrode, a plasma display panel, and a photosensitive conductive paste used to form a high-precision electrode circuit on a substrate of a plasma display panel (hereinafter, abbreviated as "PDP"). It is about.

Generally, a paste in which a metal powder is mixed with an organic binder as a method of forming a pattern of a conductor such as an electrode (hereinafter referred to as an “electrode”) on a printed wiring board or a substrate for a PDP (hereinafter referred to as a “substrate”). The screen printing method which manufactures a material and prints the said paste material on a board | substrate using a screen board and forms an electrode is used (for example, refer patent document 1 etc.).

In recent years, the demand for miniaturization, thin film formation, high density, high precision, and high reliability has been increasing in substrate materials, and accordingly, improvement of electrode processing technology is desired. In particular, regarding the electrode portion of the PDP substrate, unlike the printed wiring board, since the electrode is formed on a large PDP substrate larger than 30 inches, precision and high precision of the electrode are desired.

Here, the screen printing method described above has the advantage of low cost and good workability. However, since the precision of the printing mask depends on the precision of the mask plate making, the larger the printing mask, the larger the dimensional error of the mask pattern. For this reason, it is difficult to form a high precision electrode on the 30-inch or larger PDP board | substrate by the screen printing method, and production of the PDP in which the high precision electrode was formed became increasingly technically difficult. Moreover, in the screen printing method, it was difficult to form the electrode stably industrially stably with a line width of 100 micrometers or less.

Therefore, in recent years, as a method of obtaining an electrode more precise than the screen printing method, the formation method of the electrode using the photolithographic technique using the photosensitive electrically conductive paste is proposed (for example, refer patent document 2, patent document 3, etc.).

Here, it is necessary to mix | blend electroconductive powder with high concentration in the photosensitive electrically conductive paste used for the said method in order to ensure the electroconductivity. And as this electroconductive powder, since the noble metal with good electroconductivity like silver is generally used, there exists a problem that the cost reduction of the photosensitive electrically conductive paste is difficult. In particular, when the paste is used to form an electrode of a large-screen PDP, the cost of the paste and the PDP manufactured by using the paste is remarkably increased in proportion to its size, and further lowering of these costs is desirable in view of price competition of the PDP. It is becoming.

As a countermeasure to such a request, thinning an electrode and reducing the usage-amount of the photosensitive electrically conductive paste used for formation of an electrode is mentioned. However, there is a problem that when the electrode is made thin, the resistance of the formed electrode becomes high.

[Patent Document 1] Japanese Unexamined Patent Publication No. 10-269848 (claims)

[Patent Document 2] Japanese Patent Application Laid-Open No. 11-224531 (Patent Claims)

[Patent Document 3] Japanese Patent No. 3520798 (Patent Claims)

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and its main object is a photosensitive conductive paste capable of forming a thin film electrode having good line shape and compactness while reducing the amount of silver used as the conductive powder. To provide.

Another object of the present invention is to provide an electrode and a plasma display panel which are formed using the conductive paste.

Still another object of the present invention is to provide a method for producing the photosensitive conductive paste.

In order to achieve the said objective, the photosensitive electrically conductive paste of one aspect of this invention has the following structures.

That is, the photosensitive conductive paste of the present invention comprises an organic binder, a silver powder having a primary particle diameter of 1.0 μm or less, a specific surface area of 1.5 to 2.0 m ² / g, and a tap density of 2.0 to 5.0 g / cm ³ , a photopolymerization monomer, It is a photosensitive electrically conductive paste containing a photoinitiator, an organic solvent, and a glass frit.

Specifically, it is preferable that the compounding quantity of the said organic solvent is less than 40 mass% with respect to the organic component contained in the photosensitive electrically conductive paste. Here, this organic component refers to the organic compound (containing an organic metal compound) mix | blended with the said photosensitive electrically conductive paste, and an organic binder, a photoinitiator, a photoinitiator, an organic solvent, a dispersing agent, a stabilizer, etc. correspond specifically.

With such a configuration, the photosensitive conductive paste of the present invention can form a thin film electrode having good line shape and compactness.

In addition, specifically, it is preferable that the compounding quantity of the said silver powder is 30-45 mass parts with respect to 100 mass parts of said photosensitive electrically conductive pastes. By such a configuration, the electrode formed by using the photosensitive conductive paste of the present invention can obtain sufficient conductivity without becoming porous.

More specifically, it is preferable that the average particle diameter of the said glass frit is 1.5 micrometers or less. With such a configuration, since the shrinkage upon firing uniformly occurs in the photosensitive conductive paste of the present invention, the line shape of the electrode to be formed becomes clear, and a compact electrode can be formed.

In addition, the electrode of the present invention is characterized in that it is formed using the photosensitive conductive paste.

Specifically, the electrode formed using the photosensitive electrically conductive paste of this invention is characterized by the film thickness of 1.0 micrometer or less.

By such a configuration, the electrode of the present invention can reduce the amount of silver used, thereby achieving cost reduction of the photosensitive conductive paste and the PDP produced using the same.

In addition, the plasma display panel of the present invention is characterized by including the electrode.

In addition, in the method for producing a photosensitive conductive paste of the present invention, a glass slurry is prepared by wet dispersing or pulverizing a mixture containing a glass frit, an organic solvent, and a dispersant, wherein the glass slurry, the organic binder, and the primary particle diameter are 1.0 μm or less. And a specific surface area of 1.5 to 2.0 m ² / g and a tap density of 2.0 to 5.0 g / cm ³ , a photopolymerizable monomer, a photopolymerization initiator, and an organic solvent are mixed.

Specifically, it is preferable that the compounding quantity of the said organic solvent (containing the organic solvent contained in a glass slurry) is less than 40 mass% with respect to the organic component contained in the photosensitive electrically conductive paste manufactured by the said manufacturing method.

With such a configuration, the photosensitive conductive paste produced by the method for producing a photosensitive conductive paste of the present invention can form a thin film electrode having good line shape and compactness.

More specifically, it is preferable that the average particle diameter of the said glass frit is 1.5 micrometers or less. With such a configuration, the photosensitive conductive paste produced by the method for producing a photosensitive conductive paste of the present invention has a uniform shrinkage upon firing, so that the line shape of the electrode to be formed becomes clear, and a compact electrode can be formed.

The photosensitive electrically conductive paste of this invention can form the electrode of the thin film which has favorable line shape and compactness. Moreover, by thinning the electrode to form, the usage-amount of the photosensitive electrically conductive paste used for this electrode formation can be reduced, and also the compounding quantity of the silver contained in the said electrically conductive paste can be reduced. Thereby, the cost reduction of the photosensitive electrically conductive paste and the PDP manufactured using this can be aimed at.

Hereinafter, although an example of embodiment of this invention is described, this invention is not limited to this.

In addition, in this specification, a "coating film" means the coating film formed using the photosensitive electrically conductive paste of this invention below, and includes the thing hardened | cured by exposure.

The photosensitive conductive paste of this embodiment is characterized by containing silver powder having a primary particle diameter of 1.0 μm or less, a specific surface area of 1.5 to 2.0 m ² / g, and a tap density of 2.0 to 5.0 g / cm ³ .

Specifically, it is preferable that the compounding quantity of the said silver powder is 30-45 mass parts with respect to 100 mass parts of photosensitive electrically conductive pastes.

More specifically, it is preferable to mix | blend 40 mass% of organic solvent with the said photosensitive electrically conductive paste with respect to the organic component contained in the said photosensitive electrically conductive paste.

In addition, in the method for producing the photosensitive conductive paste of the present embodiment, a glass slurry is prepared by wet dispersing or pulverizing a mixture containing a glass frit, an organic solvent, and a dispersant, and the glass slurry, the organic binder, and the primary particle diameter are 1.0 μm or less. A silver powder having a specific surface area of 1.5 to 2.0 m ² / g and a tap density of 2.0 to 5.0 g / cm ³ is characterized by mixing a photopolymerization monomer, a photopolymerization initiator, and an organic solvent.

Specifically, it is preferable that the compounding quantity of the said organic solvent to the photosensitive electrically conductive paste is 40 mass% with respect to the organic component contained in the said photosensitive electrically conductive paste.

With such a configuration, the photosensitive conductive paste of the present embodiment and the photosensitive conductive paste produced by the method for producing the photosensitive conductive paste have a good line shape of the electrode to be formed and have a film thickness of 1.0 μm or less. can do. In addition, it is possible to form an excellent electrode having a dense coating.

Resin which has a carboxyl group is mentioned as an organic binder used for this embodiment. Specifically, it is possible to use any of the carboxyl group-containing photosensitive resin which itself has an ethylenic double bond, and the carboxyl group-containing resin which does not have an ethylenically unsaturated double bond. Moreover, the following are mentioned as resin (any of an oligomer and a polymer) which can be used suitably as an organic binder.

(1) Carboxyl group-containing resin obtained by copolymerizing unsaturated carboxylic acids, such as (meth) acrylic acid, and compounds which have unsaturated double bonds, such as methyl (meth) acrylate.

(2) About copolymers of unsaturated carboxylic acids, such as (meth) acrylic acid, and compounds which have unsaturated double bonds, such as methyl (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylic acid chloride, etc. The carboxyl group-containing photosensitive resin obtained by adding an ethylenically unsaturated group as a pendant by this.

(3) Unsaturation, such as (meth) acrylic acid, in the copolymer of the compound which has unsaturated double bonds, such as methyl (meth) acrylate, and the compound which has unsaturated double bonds, such as glycidyl (meth) acrylate The carboxyl group-containing photosensitive resin obtained by making polybasic acid anhydrides, such as tetrahydrophthalic anhydride, react with the secondary hydroxyl group produced by making carboxylic acid react.

(4) A hydroxyl group such as 2-hydroxyethyl (meth) acrylate and an unsaturated double bond are added to a copolymer of an acid anhydride having an unsaturated double bond such as maleic anhydride and a compound having an unsaturated double bond such as styrene. The carboxyl group-containing photosensitive resin obtained by making the compound which reacts carry out.

(5) The carboxyl group-containing photosensitive resin obtained by making polybasic acid anhydrides, such as tetrahydrophthalic anhydride, react with the secondary hydroxyl group produced by making a polyfunctional epoxy compound react with unsaturated carboxylic acids, such as (meth) acrylic acid.

(6) An organic acid having one carboxyl group in one molecule and not having an ethylenically unsaturated bond in an epoxy group of a copolymer of a compound having an unsaturated double bond such as methyl (meth) acrylate and glycidyl (meth) acrylate The carboxyl group-containing photosensitive resin obtained by making it react and making polybasic acid anhydride react with the secondary hydroxyl group produced by this.

(7) Carboxyl group-containing resin obtained by making polybasic acid anhydride react with hydroxyl-containing polymers, such as polyvinyl alcohol.

(8) A compound having an unsaturated double bond with an epoxy group such as glycidyl (meth) acrylate is added to a carboxyl group-containing resin obtained by reacting a hydroxyl group-containing polymer such as polyvinyl alcohol with a polybasic acid anhydride such as tetrahydrophthalic anhydride. The carboxyl group-containing photosensitive resin obtained by making it react with is mentioned. Among these, resin of (1), (2), (3), (6) is used preferably.

In addition, (meth) acrylate is a term which generically refers to acrylate, methacrylate, and mixtures thereof, and is the same also about other similar expression.

Such carboxyl group-containing photosensitive resin and carboxyl group-containing resin can also be used individually or in mixture. It is preferable that these compounding quantities are 10-50 mass parts with respect to 100 mass parts of photosensitive electrically conductive pastes. When the said compounding quantity is less than 10 mass parts, distribution of the said resin in the coating film formed using the photosensitive electroconductive paste of this invention tends to become nonuniform. In this case, it becomes difficult to obtain sufficient photocurability and photocuring depth, and the patterning by selective exposure and image development becomes difficult. On the other hand, when the said compounding quantity exceeds 50 mass parts, it becomes easy to produce the twist of the electrode at the time of baking, or shrinkage of a line width.

In addition, the resin having a carboxyl group used in the present invention preferably has a weight average molecular weight of 1,000 to 100,000 and an acid value of 50 to 250 mgKOH / g. In addition, when using carboxyl group-containing photosensitive resin as resin which has a carboxyl group, the double bond equivalent can use preferably 350-2,000g / equivalent, Preferably 400-1,500g / equivalent. When the weight average molecular weight of resin which has a carboxyl group is less than 1,000, it gives a bad influence on the adhesiveness of the coating film at the time of image development. On the other hand, when the said weight average molecular weight exceeds 100,000, it will become easy to produce the developing defect of a coating film. The more preferable range of the said weight average molecular weight is 5,000-70,000.

Moreover, when the acid value of resin which has a carboxyl group is less than 50 mgKOH / g, the solubility to aqueous alkali solution is inadequate and it is easy to produce developing defect. On the other hand, when the said acid value exceeds 250 mgKOH / g, deterioration of the adhesiveness of a coating film and dissolution of the photocurable part (exposure part) of a coating film will arise at the time of image development. Moreover, when using carboxyl group-containing photosensitive resin as resin which has a carboxyl group, if the double bond equivalent of the said resin is less than 350 g / equivalent, a residue will remain easily at the time of baking. On the other hand, when the said double bond equivalent exceeds 2,000 g / equivalent, the working margin at the time of image development of a coating film becomes narrow, and high exposure amount is needed at the time of photocuring a coating film.

The primary particle diameter of the silver powder used for this embodiment is 1.0 micrometer or less. If the primary particle size is 1.0 μm or less, shrinkage during firing occurs uniformly, so that the line shape of the electrode becomes clear, and a compact electrode can be formed. When the primary particle size is larger than 1.0 µm, pinholes and gaps are likely to occur in the conductive film after firing, and sufficient conductivity is difficult to be obtained. There is no restriction | limiting in particular about the minimum of this primary particle diameter. However, since the silver becomes more expensive when the primary particle size becomes smaller, 0.5 µm or more is preferable from the viewpoint of cost reduction. More preferable primary particle diameter is 0.5-0.7 micrometer. In addition, in this embodiment, the primary particle diameter of silver powder means the average particle diameter of ten random silver powders observed 10,000 times using the electron microscope (SEM).

In addition, the specific surface area of silver powder is 1.5-2.0 m <^2> / g. If the specific surface area of silver powder is in this range, since light scattering of silver powder is small and hardening advances fully to the lower part of a coating film, peeling does not arise at the time of image development of a coating film.

In addition, the tap density of silver powder is 2.0-5.0 g / cm <^3> . If the tap density of the silver powder is within this range, the applicability of the paste is good and a dense coating film is obtained. More preferred tap density is 2.4 to 4.2 g / cm ³ .

In addition, although the silver powder of this embodiment can use a thing of various shapes, such as spherical shape, a flake shape, and a dendrite shape, In consideration of an optical characteristic and dispersibility, it is preferable to use a spherical thing.

The compounding quantity of the silver powder to the photosensitive electrically conductive paste of this embodiment is 30-45 mass parts with respect to 100 mass parts of said electrically conductive pastes. When the compounding quantity of this silver powder is less than 30 mass parts, the electrode after baking will be in a porous state, and sufficient electroconductivity will become difficult to be obtained. Moreover, when the said compounding quantity exceeds 45 mass parts, the cost of the said electrically conductive paste and the PDP manufactured using this will increase.

The photopolymerizable monomer used for this embodiment is used in order to promote the photocurability of a composition, and to improve developability. Examples of the photopolymerizable monomer include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, polyurethane diacrylate, and trimethylolpropane. Triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, trimethylolpropane ethylene oxide modified triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and the acrylate Each of the methacrylates; Mono-, di-, tri-, or more polyesters of polybasic acids such as phthalic acid, adipic acid, maleic acid, itaconic acid, succinic acid, trimellitic acid and terephthalic acid with hydroxyalkyl (meth) acrylates Can be. These are not limited to a specific thing, Moreover, these can be used individually or in combination of 2 or more types. Among these photopolymerizable monomers, the polyfunctional monomer which has a 2 or more acryloyl group or a methacryloyl group in 1 molecule is used preferably.

The amount of such photopolymerizable monomer to be blended is suitably 20 to 100 parts by mass per 100 parts by mass of the organic binder. When the compounding quantity of the said photopolymerizable monomer is less than 20 mass parts, sufficient photocurability of a paste becomes difficult to be obtained. On the other hand, when the said compounding quantity exceeds 100 mass parts, since the photocuring of the surface part will be quick compared with the core part of a film, hardening nonuniformity will become easy to generate | occur | produce.

As a photoinitiator used for this embodiment, Specific examples include benzoin, benzoin alkyl ether, such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether; Acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, and 1,1-dichloroacetophenone; 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone- Aminoacetophenones such as 1, 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone; Anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone and 1-chloroanthraquinone; Thioxanthones, such as 2, 4- dimethyl thioxanthone, 2, 4- diethyl thioxanthone, 2-chloro thioxanthone, and 2, 4- diisopropyl thioxanthone; Ketal such as acetophenone dimethyl ketal and benzyl dimethyl ketal; Benzophenones such as benzophenone; Or xanthones; (2,6-dimethoxybenzoyl) -2,4,4-pentylphosphineoxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine Phosphine oxides such as oxide, ethyl-2,4,6-trimethylbenzoyldiphenylphosphinate; Various peroxides can be mentioned. These can be used individually or in combination of 2 or more types. As a commercial item, Irgacure-184, Irgacure-819, Irgacure -907, Irgacure-369, Irgacure-379, and the BASF company's lucy, manufactured by Ciba Specialty Chemicals Co., Ltd. Lean TPO, etc. are mentioned.

The compounding quantity of these photoinitiators is suitable 1-30 mass parts per 100 mass parts of organic binder, Preferably it is 5-20 mass parts.

In addition, such photoinitiators include light such as tertiary amines such as N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine and triethanolamine. It can be used in combination with 1 type, or 2 or more types of sensitizers.

In addition, when a deeper photocuring depth is required, a titanocene-based photopolymerization initiator (such as Irgacure-784, manufactured by Ciba Specialty Chemicals Co., Ltd.), leuco dye, and the like, which initiate radical polymerization in the visible region, is combined as a curing aid. Can be used.

Moreover, a thermal polymerization catalyst can be used together with the said photoinitiator. This thermal polymerization catalyst can react the uncured photopolymerizable monomer contained in a coating film by aging at high temperature over several minutes to about 1 hour. Specifically, it is azo compounds, such as peroxides, such as benzoyl peroxide, and isobutyronitrile. As the thermal polymerization catalyst, 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis-2,4-divalero Nitrile, 1'-azobis-1-cyclohexanecarbonitrile, dimethyl-2,2'-azobisisobutyrate, 4,4'-azobis-4-cyanovaleric acid, 2-methyl-2,2 ' Azobispropanenitrile, 2,4-dimethyl-2,2,2 ', 2'-azobispentanenitrile, 1,1'-azobis (1-acetoxy-1-phenylethane), 2,2, 2 ', 2'- azobis (2-methylbutanamide oxime) dihydrochloride, etc. are mentioned. As a more preferable example, 1,1'- azobis (1-acetoxy-1- phenyl ethane) of an environmentally friendly non-cyanide and non-halogen type is mentioned.

As an organic solvent used for this embodiment, Ketones, such as methyl ethyl ketone and cyclohexanone, specifically; Aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; Glycol ethers such as cellosolve, methyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monoethyl ether ; Ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, etc. Esters of; Alcohols such as ethanol, propanol, ethylene glycol, propylene glycol and terpineol; Aliphatic hydrocarbons such as octane and decane; Petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha and solvent naphtha. These can be used individually or in combination of 2 or more types.

It is preferable to mix | blend such an organic solvent so that it may become less than 40 mass% with respect to the organic component contained in the photosensitive electrically conductive paste. When the compounding quantity of an organic solvent is 40 mass% or more with respect to an organic component, the viscosity of a paste will become low and applicability | paintability will deteriorate. In addition, sedimentation or the like occurs and the storage stability of the paste is lowered.

It is preferable that the glass softening point used for this embodiment is a glass softening point of 420-580 degreeC. More preferably, the glass transition point is 360-500 degreeC. Moreover, it is preferable that average particle diameter is 0.2-1.0 micrometer. When the average particle diameter of the glass frit is 1.0 μm or less, shrinkage during firing occurs uniformly, and the line shape of the electrode becomes clear, so that an electrode of a dense film can be formed. Moreover, it is preferable that the thermal expansion coefficient (alpha) 300 of glass frit is 60-110x10 <^-7> .

As such glass frit, those having a main component of lead oxide, bismuth oxide, zinc oxide, lithium oxide, or alkali borosilicate are preferably used.

As a glass frit mainly composed of lead oxide, PbO is 48 to 82%, B ₂ O ₃ is 0.5 to 22%, SiO ₂ is 3 to 32%, and Al ₂ O ₃ is 0 to 12 by mass% based on oxide. %, BaO may be mentioned are the amorphous glass frit from 0 to 15%, TiO ₂ 0 to 2.5%, Bi ₂ O ₃ is a composition having from 0 to 25%, a softening point of 420 to 580 ℃.

Examples preferred for the glass frit mainly composed of bismuth oxide, in% by weight of the oxide basis, Bi ₂ O ₃ is from 6 to 88%, B ₂ O ₃ is from 5 to 30%, SiO ₂ is from 5 to 25%, Al ₂ O _An amorphous glass frit having a composition having _trivalent 0 to 5%, BaO 0 to 20% and ZnO 1 to 20%, and having a softening point of 420 to 580 ° C.

As a preferable example of the glass frit mainly containing zinc oxide, ZnO is 25 to 60%, K ₂ O is 2 to 15%, B ₂ O ₃ is 25 to 45%, and SiO ₂ is 1 to 7 by mass% based on the oxide. % Al ₂ O ₃ may be mentioned is the amorphous glass frit is 0-10%, BaO is 0 to 20%, having a composition of MgO is 0 to 10%, a softening point of 420 to 580 ℃.

The blending amount of such glass frit is 1 to 30 parts by mass, preferably 1 to 20 parts by mass with respect to 100 parts by mass of silver powder in terms of improving the adhesiveness of the electrode after firing and reducing the resistance.

In addition, a dispersing agent can be added to the photosensitive electrically conductive paste of this embodiment in order to disperse | distribute a glass frit uniformly to the said paste. The dispersant is not particularly limited as long as the glass frit can be uniformly dispersed in the paste, and may be used alone or in combination of two or more thereof. As a dispersing agent, a polycarboxylic acid type polymeric surfactant, a modified acrylic block copolymer, the acrylic copolymer which has a pigment affinity group, the block copolymer which has a basic or acidic pigment adsorption group, the modified polyalkoxylate which has a pigment affinity group, polyamino A combination of an amide salt and a polyester, or a combination of a polar acid ester and a polymer alcohol, an alkylammonium salt of an acidic polymer, a high molecular weight block copolymer having a pigment affinity group, a specially modified urea, and the like, but are particularly limited thereto. no.

Commercially available dispersants (including rheology control agents for preventing sedimentation) are particularly preferably used as modalflow (manufactured by Monsanto), Disperbyk (registered trademark) -101, -103,- 110, -111, -160, -171, -174, -182, -184, -190, -300, -BYK®-P105, -P104, -P104S, -240, -410 (all big chemies) Japan Co., Ltd.) is mentioned.

In addition, the glass slurry of this embodiment is manufactured by wet-dispersing a mixture containing 40-90 mass parts of glass frits, 10-60 mass parts of organic solvents, and 0.03-10 mass parts of a dispersing agent (it contains grinding | pulverization and is the same below). do. As a preferable aspect, it is a glass slurry which wet-disperses the mixture containing 50-85 mass parts of glass frits, 15-50 mass parts of organic solvents, and 0.1-8 mass parts of dispersing agents.

Moreover, as a wet disperser used for manufacture of a glass slurry, a sand mill, a ball mill, a bead mill, an attritor, etc. are mentioned. Among these, bead mill is preferable from productivity and dispersibility. The dispersant may be added at the time of wet dispersion, or after that. When the content of the glass frit is high, the viscosity of the glass slurry is also increased, and therefore it is preferable to add a dispersant having a high viscosity reducing effect during wet dispersion.

In addition, the glass slurry can perform high precision filtration according to the grinding degree. In particular, it is preferable to paste after filtering a glass slurry with the filtration filter which becomes 98 mass% filtration precision of 2-40 micrometers, Preferably it becomes 98 mass% filtration accuracy of 5 to 33 micrometers. Thereby, the electrode of the dense film which does not generate | occur | produce pinhole etc. can be formed. In addition, a glass slurry shows the solution in which the glass fine particle disperse | distributed (or suspended) in the liquid, and includes the thing by which glass was pulverized at the time of dispersion.

When a large amount of inorganic powder is mix | blended with the photosensitive electrically conductive paste of this embodiment, the storage stability of the composition obtained is bad, and there exists a tendency for coating workability to worsen by gelatinization and fluidity fall. Therefore, in the composition of this embodiment, in order to improve the storage stability of a composition, the compound which has the effect of complexing with the metal or oxide powder which is a component of an inorganic powder, or salt formation with these, can be added as a stabilizer.

As a stabilizer of this embodiment, Various inorganic acids, such as nitric acid, a sulfuric acid, hydrochloric acid, a boric acid; Various organic acids such as formic acid, acetic acid, acetoacetic acid, citric acid, stearic acid, maleic acid, fumaric acid, phthalic acid, benzenesulfonic acid and sulfamic acid; Phosphoric acid, phosphorous acid, hypophosphorous acid, methyl phosphate, ethyl phosphate, butyl phosphate, phenyl phosphate, ethyl phosphite, diphenyl phosphite, mono (2-methacryloyloxyethyl) acid phosphate, di (2-methacryloyloxyethyl Acids, such as various phosphoric acid compounds (inorganic phosphoric acid, organophosphoric acid), such as an acid phosphate, are mentioned. These can be used individually or in combination of 2 or more types. Such stabilizers are preferably added at a ratio of 0.1 to 10 parts by mass per 100 parts by mass of the glass powder and the inorganic powder.

In addition, when boric acid is mix | blended as a stabilizer, it is preferable to use the hydrophobic solvent whose solubility with respect to 100 g of 25 degreeC water is 20 g or less. When an organic solvent having high solubility in water is used, water dissolved in the organic solvent ionizes the metal contained in the glass frit, causing gelation.

Moreover, additives, such as a defoaming and leveling agent, such as a silicone type and an acryl type, and the silane coupling agent for the adhesive improvement of a film, can be mix | blended with the photosensitive electrically conductive paste of this embodiment. In addition, an antioxidant, a thermal polymerization inhibitor for improving the thermal stability at the time of storage, etc. can also be added to the photosensitive electrically conductive paste of this embodiment.

The photosensitive electrically conductive paste of this embodiment is apply | coated to a board | substrate, for example, a glass substrate used as a front substrate of a PDP by the screen printing method, the coating method, such as a bar coater and a blade coater. After coating, this is dried in a hot air circulation drying furnace, a far-infrared drying furnace, or the like for 5 to 40 minutes, for example, at 70 to 120 ° C. to evaporate the dryness, and the organic solvent contained in the paste is evaporated to obtain tack free. A coating film is formed. When a dry film is formed using the said paste previously, you may laminate the resin composition layer of this dry film on a board | substrate. After formation of the coating film, the coating film is subjected to selective exposure, development and firing to form an electrode.

In an exposure process, contact exposure and non-contact exposure using the negative mask which has an exposure pattern are possible. As the exposure light source, a halogen lamp, a high pressure mercury lamp, a laser light, a metal halide lamp, a black lamp, an electrodeless lamp and the like are used. As an exposure amount, about 100-800 mJ / cm <^2> is preferable.

In the developing step, a spraying method, an immersion method, or the like is used. As a developing solution, aqueous solution of metal alkalis, such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and sodium silicate, and aqueous solution of amines, such as monoethanolamine, diethanolamine, and triethanolamine, especially the rare alkaline aqueous solution of about 1.5 mass% or less Is preferably used. Moreover, as a developing solution, the carboxyl group of resin which has a carboxyl group contained in a coating film should be saponified, and the unhardened part (unexposed part) should just be removed, and it is not limited to the above-mentioned developing solution. In addition, it is preferable to wash with water and acid neutralize a board | substrate after image development, in order to remove the unnecessary developer.

In the firing step, the substrate after development is subjected to heat treatment at about 400 to 600 ° C. under an air atmosphere or a nitrogen atmosphere to form an electrode. In addition, it is preferable to set the temperature increase rate at this time to 20 degrees C / min or less.

<Examples>

Although an Example and a comparative example are described below and this embodiment is demonstrated concretely, of course, this invention is not limited to the following Example.

(Synthesis of Organic Binder)

Methyl methacrylate and methacrylic acid were charged to a flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser at a molar ratio of 0.76: 0.24, and dipropylene glycol monomethyl ether as a solvent and azobisisobutyro as a catalyst were added thereto. Nitrile was added and these were stirred at 80 degreeC for 2 to 6 hours in nitrogen atmosphere, and the resin solution was obtained. This resin solution is cooled, methylhydroquinone as a polymerization inhibitor and tetrabutylphosphonium bromide as a catalyst are used for this, and glycidyl methacrylate is further added under the conditions of 16 hours at 95 to 105 캜. The addition reaction was carried out at an addition molar ratio of 0.12 mol to 1 mol of the carboxyl groups. After cooling, these were taken out as organic binder A. This organic binder A had a weight average molecular weight of about 10,000, a solid acid value of 59 mgKOH / g, and a double bond equivalent of 950. In addition, the weight average molecular weight of binder A is three pump LC-6AD by the Shimadzu Corporation company and column Shodex (trademark) KF-804, KF-803, and KF-802 by Showa Denko Co., Ltd. It measured by the connected high performance liquid chromatography.

Using this organic binder A, each component is mix | blended in the composition ratio shown in Table 1, and after stirring with a stirrer, these are ground using a triaxial roll mill and pasteurized, Examples 1-6 and Comparative Example 1, Each photosensitive electrically conductive paste of 2 was produced. In addition, the unit of the compounding quantity of each component shown in Table 1 is a mass part.

As the low melting glass frit, Bi ₂ O ₃ 50%, B ₂ O ₃ 16%, ZnO 14%, SiO ₂ 2%, BaO 18%, thermal expansion coefficient α300 = 86 × 10 ⁻⁷ / ° C., glass softening point 501 ° C. Was used.

The glass frit was pulverized by a jet mill and measured by a Horiba laser diffraction / scattering particle size distribution analyzer LA-920, and the average particle diameter was 1.3 m.

[0067]

(Ag powder)

In this example, Ag powders A to E having different specific surface areas, tap densities, and primary particle sizes shown in Table 2 were used.

(Test piece production)

Each photosensitive electrically conductive paste for evaluation was apply | coated to the whole surface on the glass substrate using the 300-mesh polyester screen, Then, these were dried in IR drying furnace at 100 degreeC for 20 minutes, and the coating film with favorable dryness property was formed. It was. Next, using a shot arc lamp as a light source, pattern exposure of the dry coating film so that the accumulated light amount on a dry coating film may be 300 mJ / cm <^2> through a negative mask, and this image development using 0.4 mass% aqueous solution of sodium carbonate. And washed with water. And the said board | substrate was baked at 590 degreeC for 10 minutes in air atmosphere, and each test piece in which the electrode was formed was manufactured. These evaluation methods are as follows.

(Line shape and compactness);

The defect of the 100 micrometer-wide electrode formed by the said test piece manufacturing method was evaluated by microscope observation.

(Circle) and NG were made into x for favorable cases.

(Resistance value);

The test piece which has an electrode of 0.4x10 cm was produced by the said test piece manufacturing method, and the specific resistance value was computed from the resistance value and the film thickness of the formed electrode.

Resistance measurement: Measured by milliohm high tester.

(Preservation stability);

Each photosensitive electrically conductive paste of Examples 1-6 and Comparative Example 1 was left to stand on 25 degreeC for 7 days, and the sedimentation state after that was observed.

(Circle) and no sedimentation were made into x without sedimentation.

The evaluation results are shown in Table 2.

As is clear from Examples 1 to 6 and Comparative Example 1 shown in Table 2, according to the photosensitive conductive paste of the present embodiment, a thin film electrode having a good line shape, resistance value and compactness and having a film thickness of 1.0 μm or less is formed. I could confirm that I could.

Claims (5)

The film thickness of the electrode formed using a paste is 1.2 μm or less,
The paste
Organic binders,
Silver powder having a primary particle diameter of 1.0 μm or less, a specific surface area of 1.5 to 2.0 m ² / g, and a tap density of 2.0 to 5.0 g / cm ³ ,
Photopolymerization monomer,
Photopolymerization initiator,
With organic solvents,
Contains glass frit,
The compounding quantity of the said glass frit is 1-30 mass parts with respect to 100 mass parts of silver powders, The photosensitive electrically conductive paste characterized by the above-mentioned. The photosensitive conductive paste according to claim 1, wherein a compounding amount of the silver powder is 30 to 45 parts by mass with respect to 100 parts by mass of the photosensitive conductive paste. Organic binders,
Silver powder having a primary particle diameter of 1.0 μm or less, a specific surface area of 1.5 to 2.0 m ² / g, and a tap density of 2.0 to 5.0 g / cm ³ ,
Photopolymerization monomer,
Photopolymerization initiator,
With organic solvents,
Contains glass frit,
The photosensitive electrically conductive paste whose compounding quantity of the said glass frit is 1-30 mass parts with respect to 100 mass parts of silver powders.
An electrode having a film thickness of 1.2 μm or less, which is formed by using a film. A plasma display panel comprising the electrode according to claim 3. The film thickness of the electrode formed using a paste is 1.2 μm or less,
In the method for preparing the paste, a glass slurry is prepared by wet dispersing or pulverizing a mixture including a glass frit, an organic solvent, and a dispersant,
The glass slurry, an organic binder, a silver powder having a primary particle diameter of 1.0 μm or less, a specific surface area of 1.5 to 2.0 m ² / g, and a tap density of 2.0 to 5.0 g / cm ³ , a photopolymerization monomer, a photopolymerization initiator, Mixing organic solvents,
The compounding quantity of the said glass frit is 1-30 mass parts with respect to 100 mass parts of silver powders, The manufacturing method of the photosensitive electrically conductive paste characterized by the above-mentioned.