KR101250602B1 - Photosensitive conductive paste and method for producing the same - Google Patents

Abstract

The present invention provides a photosensitive conductive paste capable of forming an electrode pattern of a thin film having good resistivity value and compactness.
According to the present invention, there is provided a photosensitive conductive paste containing an organic binder, silver powder, a photopolymerization monomer, a photopolymerization initiator, an organic solvent, and a glass frit, wherein the silver powder has a primary particle size of 0.7 µm or less and a specific surface area. 1.4-2.0 m <2> / g and tap density 2.0-5.0 g / cm <3> are satisfy | filled, and 15 mass% or more and less than 35 mass% of the said photosensitive electrically conductive paste are contained, The said glass frit has an average particle diameter of 0.3-1,5 micrometers, In addition, the softening point is characterized in that the 530 to 650 ℃.

Description

Photosensitive conductive paste and its manufacturing method {PHOTOSENSITIVE CONDUCTIVE PASTE AND METHOD FOR PRODUCING THE SAME}

The present invention relates to, for example, a photosensitive conductive paste used to form an address electrode on a circuit board of a plasma display panel (hereinafter referred to as a PDP) and a manufacturing method thereof.

Generally, when forming a conductor pattern such as an electrode on a circuit board, a method of printing a conductive paste material obtained by mixing a metal powder with an organic binder on a circuit board by screen printing or the like is used (for example, See Patent Document 1, etc.).

In recent years, for example, with large screens and high precision of PDPs, it is required to form high-precision address electrodes having a line width of 100 µm or less stably even on circuit boards of more than 30 inches. However, such a printing technique is difficult to form a high precision conductor pattern on a large circuit board.

Therefore, the method of forming a conductor pattern by the photolithographic technique using the photosensitive electrically conductive paste is proposed (for example, refer patent document 2, patent document 3, etc.). In the photosensitive electrically conductive paste used for such a method, electroconductive precious metals, such as silver, are used as electroconductive powder. In particular, when used for a large screen PDP, since the amount of use thereof is proportional to the size, there is a problem that the production cost increases. Therefore, reduction of content of silver powder and thinning of the conductor pattern have been studied to reduce the cost.

However, in the conductor pattern of the thin film with such a low silver powder content, it is difficult to obtain good compactness, and there exists a problem that a specific resistance value rises.

Japanese Patent Laid-Open No. 10-269848 (claims, etc.) Japanese Patent Laid-Open No. 11-224531 (claims, etc.) Japanese Patent No. 3520798 (claims, etc.)

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and provides a photosensitive conductive paste capable of forming a conductive pattern of a thin film having a high precision, high resistivity and good density, and reducing the content of silver powder. The purpose.

The photosensitive conductive paste of one embodiment of the present invention is a photosensitive conductive paste containing an organic binder, silver powder, a photopolymerization monomer, a photopolymerization initiator, an organic solvent, and a glass frit, and the silver powder has a primary particle diameter of 0.7 μm. Hereinafter, the specific surface area of 1.4 to 2.0 m 2 / g and the tap density of 2.0 to 5.0 g / cm 3 are all satisfied, and 15 to 35% by mass of the photosensitive conductive paste is contained, and the glass frit has an average particle diameter (D50) of 0.3 to 1.5 µm, and a softening point of 530 to 650 ° C.

By this structure, it becomes possible to form the ultra-thin conductor pattern which has high precision, favorable specific resistance value, and compactness, while reducing content of silver powder.

It is preferable that content of the glass frit in such a photosensitive electrically conductive paste is 0.01-35 mass parts with respect to 100 mass parts of silver powder. By making content of a glass frit into this range, favorable specific resistance value and compactness can also be obtained with the conductor pattern formed. When glass frit is less than 0.01 mass part, it becomes difficult to obtain favorable adhesiveness with respect to a board | substrate, and when it exceeds 35 mass parts, it will become difficult to obtain favorable compactness and a specific resistance value.

In one embodiment of the present invention, such a photosensitive conductive paste can be used to form a conductor pattern. And in the obtained conductor pattern, it can be set as a high-definition thin film which has favorable specific resistance value and compactness with content of a little silver powder.

Moreover, more preferable specific resistance value and compactness can be obtained by making content of the glass frit of the obtained conductor pattern into 0.01-35 mass parts with respect to 100 mass parts of silver powder.

And the film thickness of such a conductor pattern can be 1.2 micrometers or less, and it becomes possible to reduce the usage-amount of silver powder, and to aim at cost reduction.

In addition, such a conductor pattern can be preferably used for PDP.

According to one aspect of the present invention, it is possible to reduce the content of silver powder and to form a conductor pattern of a thin film having high precision and good specific resistance value and compactness.

Hereinafter, the photosensitive electrically conductive paste of this embodiment is demonstrated in detail.

The photosensitive conductive paste of this embodiment is a photosensitive conductive paste containing an organic binder, silver powder, a photopolymerization monomer, a photopolymerization initiator, an organic solvent, and a glass frit, wherein the silver powder has a primary particle size of 0.7 μm or less, It satisfies all of the specific surface area 1.4-2.0 m <2> / g and tap density 2.0-5.0 g / cm <3>, and contains 15 mass% or more and less than 35 mass% of the photosensitive electrically conductive paste, and the glass frit has an average particle diameter (D50) of 0.3-1.5 micrometers. , Characterized in that the softening point is 530 to 650 ℃.

In such a photosensitive electrically conductive paste, an organic binder is used in order to form a pattern in a coating film by disperse | distributing silver powder, making it applyable on a board | substrate, and developing by pattern exposure.

As the organic binder, both a resin having a carboxyl group, specifically, a carboxyl group-containing photosensitive resin having an ethylenic double bond and a carboxyl group-containing resin not having an ethylenically unsaturated double bond can be used. Examples of the resin (which may be either oligomer or polymer) that can be preferably used include the following ones.

(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) Ethylene by glycidyl (meth) acrylate, (meth) acrylic acid chloride or the like in a copolymer of an unsaturated carboxylic acid such as (meth) acrylic acid and an unsaturated double bond such as methyl (meth) acrylate Carboxyl group containing photosensitive resin obtained by adding a unsaturated unsaturated group as a pendant.

(3) unsaturated carboxyl such as (meth) acrylic acid in a copolymer of a compound having an unsaturated double bond such as methyl (meth) acrylate with an epoxy group such as glycidyl (meth) acrylate; A carboxyl group-containing photosensitive resin obtained by making an acid react and making polybasic acid anhydrides, such as tetrahydrophthalic anhydride, react with the produced | generated secondary hydroxyl group.

(4) Compounds having an unsaturated double bond, such as 2-hydroxyethyl (meth) acrylate, in 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 Carboxyl group containing photosensitive resin obtained by making it react.

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

(6) An organic acid having one carboxyl group in one molecule of an epoxy group of a copolymer having a unsaturated double bond such as methyl (meth) acrylate and a glycidyl (meth) acrylate and having no ethylenically unsaturated bond. The carboxyl group-containing photosensitive resin obtained by making it react and making polybasic acid anhydride react with the produced | generated secondary hydroxyl group.

(7) Carboxyl group-containing resin obtained by making polybasic 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 further reacted with a carboxyl group-containing resin obtained by reacting a polybasic acid anhydride such as tetrahydrophthalic anhydride with a hydroxyl group-containing polymer such as polyvinyl alcohol. Carboxyl group-containing photosensitive resin obtained by making it stand.

Among these, especially 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 it is the same also about another similar expression below.

Although these carboxyl group-containing photosensitive resin and carboxyl group-containing resin can be used individually or in mixture, in any case, it is preferable that these are mix | blended in 10-50 mass parts with respect to 100 mass parts of photosensitive electrically conductive pastes in total. When the blending amount of these polymers is less than 10 parts by mass, the distribution of these resins in the coating film to be formed tends to be uneven, and it becomes difficult to obtain sufficient photocurability and photocuring depth, and patterning by selective exposure and development becomes difficult. On the other hand, when it exceeds 50 mass parts, it becomes easy to produce the twist of a pattern at the time of baking, or shrinkage of a line width.

Moreover, it is preferable that weight average molecular weights are 1,000-100,000 as carboxyl group-containing photosensitive resin and carboxyl group-containing resin, respectively. When the weight average molecular weight of these resins is less than 1,000, the adhesiveness of the coating film at the time of image development will deteriorate, and when it exceeds 100,000, it will become easy to produce developing defects. More preferably, it is 5,000-70,000.

And it is preferable that the acid value of these resin is 50-250 mgKOH / g. If the acid value is less than 50 mgKOH / g, the solubility in an aqueous alkali solution is insufficient to cause development defects. On the other hand, if the acid value is more than 250 mgKOH / g, deterioration of adhesion of the coating film at the time of development, Dissolution occurs.

Moreover, it is preferable that the double bond equivalent of carboxyl group-containing photosensitive resin is 350-2,000 g / equivalent. When the double bond equivalent of carboxyl group-containing photosensitive resin is less than 350 g / equivalent, the residue will remain easily at the time of baking. On the other hand, when it exceeds 2,000 g / equivalent, the work margin at the time of image development is narrow, and high exposure amount is required at the time of photocuring. More preferably, it is 400-1,500 g / equivalent.

In addition, in the photosensitive electrically conductive paste of this embodiment, in order to provide electroconductivity to a conductor pattern, silver powder is used.

The primary particle diameter (SEM diameter) of silver powder shall be 0.7 micrometer or less. If the primary particle size is 0.7 µm or less, shrinkage occurs uniformly during firing, and the line shape is sharp, thereby forming a dense film. When the primary particle size is larger than 0.7 µm, pinholes and gaps are likely to occur in the conductive coating film after firing, and it becomes difficult to obtain sufficient conductivity. Although there is no restriction | limiting in particular about a minimum, Since it becomes more expensive when a particle diameter becomes small, 0.5 micrometer or more is preferable from a viewpoint of cost reduction.

In addition, in this embodiment, the primary particle diameter of silver powder can be calculated | required as an average particle diameter which observed and measured ten silver powders at random 10,000 times using an electron microscope (SEM).

In addition, the specific surface area shall be 1.4-2.0 m <2> / g. By setting it as this range, light scatters little, hardening fully advances to the lower part of a coating film, and peeling of a coating film at the time of image development can be suppressed.

In addition, the tap density shall be 2.0-5.0 g / cm <3>. By setting it as this range, the paste applicability | paintability is favorable and a compact conductor pattern can be obtained. More preferably, it is 2.4 to 4.2 g / cm <3>.

As such a silver powder, various shapes, such as spherical shape, a flake shape, and a dendrite shape, can be used, but in consideration of optical characteristics and dispersibility, it is preferable to use a spherical thing.

The silver powder which satisfies the conditions of such a primary particle diameter of 0.7 micrometer or less, specific surface area 1.4-2.0 m <2> / g, and tap density 2.0-5.0 g / cm <3> is mix | blended so that it may be 15 mass% or more and less than 35 mass% of the photosensitive electrically conductive paste. do. When less than 15 mass%, the electrode after baking becomes a porous state, and it becomes difficult to acquire sufficient electroconductivity. Moreover, when it is 35 mass% or more, it will become a cost increase.

In the photosensitive electrically conductive paste of this embodiment, in order to promote photocurability and to improve developability, a photopolymerizable monomer is used.

As a photopolymerizable monomer, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethyleneglycol diacrylate, polyurethane diacrylamide, for example. Latex, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, trimethylolpropane ethylene oxide modified triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate and the above Methacrylates corresponding to acrylates; 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. have.

In addition, a photopolymerizable monomer is not limited to these, 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 preferable.

20-100 mass parts is suitable for the compounding quantity of such a photopolymerizable monomer per 100 mass parts of organic binders. When the compounding quantity of a photopolymerizable monomer is less than 20 mass parts, it becomes difficult to obtain sufficient photocurability, and when it exceeds 100 mass parts, photocuring of the surface part will become quick compared with the core part of a coating film, and it will become easy to produce a hardening nonuniformity.

In the photosensitive electrically conductive paste of this embodiment, in order to generate | occur | produce a radical by pattern exposure and to accelerate photocuring, a photoinitiator is used.

As a photoinitiator, As a specific example, Benzoin and 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-methyl anthraquinone, 2-ethyl anthraquinone, 2-t-butyl anthraquinone, and 1-chloro anthraquinone; Thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone and 2,4-diisopropylthioxanthone; 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.

As a commercial item, the Irgacure 184, Irgacure 819, Irgacure 907, Irgacure 369, Irgacure 379, the BASF company made, for example, the Irgacure 184 by Chiba Japan Can be. In addition, it is not limited to these, These photoinitiators can be used individually or in combination of 2 or more types.

As for the compounding ratio of these photoinitiators, 1-30 mass parts is preferable per 100 mass parts of organic binders. If it is less than 1 mass part, it will become difficult to fully accelerate photocuring, and when it exceeds 30 mass parts, a line will become thick easily, and it will become difficult to obtain reproduction of the line width with respect to an exposure pattern. More preferably, it is 5-20 mass parts.

Such photoinitiators are similar to 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 photosensitizers.

Moreover, when deeper photocuring depth is required, titanocene type photoinitiators, such as Irgacure (trademark) 784 (made by Chiba Japan company) by Chiba Japan Inc. which start radical polymerization in a visible region as needed, A leuco dye etc. can be used in combination as a hardening adjuvant.

Moreover, in combination with such a photoinitiator, a thermal polymerization catalyst can be used in order to react an uncured photopolymerizable monomer as needed. This thermal polymerization catalyst can react the uncured photopolymerizable monomer by aging at high temperature for several minutes to 1 hour.

Specifically, it is an azo compound, such as a peroxide, such as benzoyl peroxide, and isobutyronitrile, Preferably it is 2.2'- azobisisobutyronitrile, 2,2'- azobis-2-methylbutyronitrile, 2, 2'-azobis-2,4-divaleronitrile, 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, and the like, and more preferably, an environmentally friendly non-cyanide, non-halogen type. And 1,1'-azobis (1-acetoxy-1-phenylethane).

In the photosensitive electrically conductive paste of this embodiment, in order to adjust a viscosity and to form a uniform coating film, the organic solvent is used.

As an organic solvent, 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, are mentioned, These can be used individually or in combination of 2 or more types.

It is preferable that such an organic solvent (including an organic solvent in a glass slurry) is mix | blended so that it may be less than 40 weight% with respect to the organic component in the photosensitive electrically conductive paste. If it is 40 weight% or more, a viscosity will become low and applicability | paintability will deteriorate. In addition, sedimentation and the like occur, and storage stability is lowered.

In addition, an organic component is an organic compound (including an organic metal compound) mix | blended in the photosensitive electrically conductive paste. Specifically, it is all organic compounds, such as a dispersing agent and a stabilizer other than an organic binder, a photopolymerization monomer, a photoinitiator, and an organic solvent.

In the photosensitive electrically conductive paste of this embodiment, in order to improve the adhesiveness with respect to the board | substrate of the conductor pattern after baking, a glass frit is used.

The average particle diameter (D50) of the glass frit is 0.3 to 1.5 m. If the average particle diameter is less than 0.3 m, the yield is considerably lowered and the cost is increased. If the average particle diameter is more than 1.5 m, uniform shrinkage during formation or firing of the thin film becomes difficult, resulting in deterioration of line shape and compactness.

In addition, the softening point of a glass frit shall be 530-650 degreeC. If the glass softening point is less than 530 ° C, it is difficult to obtain sufficient compactness in the conductor pattern obtained, and if it exceeds 650 ° C, the resistance value rises.

As such a glass frit, one having lead oxide, bismuth oxide, zinc oxide, lithium oxide or alkali borosilicate as a main component is preferably used.

A glass frit mainly composed of lead oxide, for example in terms of percent by mass of the oxide-based, PbO 48 to 82%, B ₂ O ₃ is 0.5 to 22%, SiO ₂ is from 3 to 32%, Al ₂ O ₃ An amorphous glass frit having a composition of 0 to 12%, BaO of 0 to 15%, TiO ₂ of 0 to 2.5%, and Bi ₂ O ₃ of 0 to 25%.

As a glass frit containing bismuth oxide as a main component, in mass% on the basis of oxide, Bi ₂ O ₃ is 6 to 88%, B ₂ O ₃ is 5 to 30%, SiO ₂ is 5 to 25%, and Al ₂ O ₃ An amorphous glass frit having a composition of 0 to 5%, BaO of 0 to 20% and ZnO of 1 to 20% is preferable.

As a glass frit containing zinc oxide as a main component, 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. An amorphous glass frit having a composition of 0%, Al ₂ O ₃ of 0 to 10%, BaO of 0 to 20%, and MgO of 0 to 10% is preferred.

It is preferable that the compounding quantity of this glass frit is 0.01-35 mass parts with respect to 100 mass parts of silver powder. If it is less than 0.01 mass part, it will become difficult to obtain favorable adhesiveness with respect to the board | substrate of the conductor pattern after baking. On the other hand, when it exceeds 35 mass parts, it will become difficult to obtain favorable density and a specific resistance value. More preferably, it is 1-20 mass parts. Moreover, it is preferable that the thermal expansion coefficient (alpha) 300 of such a glass frit is 60-110x10 <^-7> .

In such a photosensitive electrically conductive paste, in order to disperse | distribute the glass frit uniformly in a photosensitive electrically conductive paste, a dispersing agent can be further added.

The dispersant may be any one capable of uniformly dispersing the glass frit, and is not particularly limited. For example, polycarboxylic acid type polymer surfactant, modified acrylic block copolymer, acrylic copolymer having a pigment affinity group, block copolymer having a basic or acidic pigment adsorbent, modified polyalkoxylate having a pigment affinity group, poly Aminoamide salt and polyester, a combination of a polar acid ester and a polymer alcohol, the alkylammonium salt of an acidic polymer, a high molecular weight block copolymer which has a pigment affinity group, a special modified urea, etc. are mentioned, but it is not specifically limited to this.

Particularly preferably usable in commercially available dispersants (including rheology control agents for preventing sedimentation) are Modaflow (manufactured by Monsanto), Disperbyk (registered trademark) -101, -103, -110, -111, -160, -171, -174, -182, -184, -190, -300, BYK®-P105, -P104, -P104S, -240, -410 Manufactured), EFKA-polymer 150, Efka-44, -63, -64, -65, -66, -71, -764, -766, and N (all are manufactured by Efka Corporation).

In addition, a dispersing agent is not limited to these, These dispersing agents can be used individually or in combination of 2 or more types.

In such a photosensitive electrically conductive paste, a stabilizer can be further added in order to improve storage stability and to suppress deterioration of coating workability by gelatinization and fluidity fall.

As such a stabilizer, the compound which has the effect of complexing with metal or oxide which is a component of inorganic powders, such as silver powder and glass frit, or salt formation, in a photosensitive electrically conductive paste can be used.

Specifically, for example, various inorganic acids such as nitric acid, sulfuric acid, hydrochloric acid and 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 and organic phosphoric acid), such as an acid phosphate, are mentioned.

In addition, a stabilizer is not limited to these and can also use these individually or in combination of 2 or more types. It is preferable to add such a stabilizer in the ratio of 0.1-10 mass parts with respect to 100 mass parts of inorganic powders.

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 water at 25 degreeC is 20 g or less. If 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, in the photosensitive electrically conductive paste of this embodiment, other additives, such as a vesicle-leveling agent, such as a silicone type and an acryl type, and a silane coupling agent for improving the adhesiveness of a coating film, can be mix | blended as needed. Moreover, if necessary, a known antioxidant, a thermal polymerization inhibitor for improving the thermal stability at the time of storage, etc. can also be added.

In this embodiment, although the photosensitive electrically conductive paste comprised in this way is manufactured by mixing each component, in order to make a glass frit fine and to disperse | distribute it uniformly, it is preferable to manufacture a glass slurry previously.

First, the glass slurry of the soft frit point 530-650 degreeC, an organic solvent, a dispersing agent, etc. are mixed, and it is wet-dispersed, and the glass slurry of 0.3-1.5 micrometers of average particle diameters (D50) of a glass frit is manufactured. 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 the glass was grind | pulverized at the time of dispersion.

Examples of the wet disperser used for the production of such glass slurry include sand mills, ball mills, bead mills, attritors, and the like, but bead mills are preferable from productivity and dispersibility. The dispersant may be added at the time of wet dispersion (including pulverization) or at a later time. However, since the viscosity of the glass frit is high, the dispersant may have a deterioration effect at the time of wet dispersion (including pulverization). Preference is given to adding high dispersants.

In addition, the glass slurry is preferably subjected to high-precision filtration according to the degree of grinding thereof in order to form a dense film without the occurrence of pinholes or the like. At this time, it is preferable to use the filtration filter used as 98 mass% filtration accuracy of 2-40 micrometers.

The photosensitive electrically conductive paste is manufactured by mixing an organic binder, a photopolymerization monomer, a photoinitiator, an organic solvent, and predetermined | prescribed silver powder to the glass slurry produced in this way. At this time, after stirring with a stirrer, it can be made into a paste by a triaxial roll mill or the like.

The photosensitive conductive paste thus prepared is applied to a substrate such as a glass substrate, which becomes a front substrate of a PDP, by a suitable coating method such as a screen printing method, a bar coder or a blade coater to form a coating film.

Subsequently, in order to obtain a touch drying property, the obtained coating film is dried in a hot air circulation drying furnace, a far-infrared drying furnace, etc., for example at about 70 to 120 ° C. for about 5 to 40 minutes, and the organic solvent is evaporated to obtain a tack-free coating film (drying). Coating film). At this time, when a photosensitive electrically conductive paste is apply | coated on a film previously, and a dry film is formed, you may laminate a dry film on a board | substrate.

And the obtained dry coating film is pattern-exposed. As the exposure method, contact exposure and non-contact exposure using a negative mask having a predetermined 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.

Furthermore, the coating film exposed to the predetermined pattern is developed. As the developing method, a spray method, an immersion method, or the like is used. As the developing solution, the carboxyl group of the carboxyl group-containing resin of the photosensitive conductive paste may be saponified, and the uncured portion (unexposed portion) may be removed. For example, aqueous metal alkali solutions such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate and sodium silicate, and aqueous amine solutions such as monoethanolamine, diethanolamine, and triethanolamine, in particular, diluted aqueous alkali solution at a concentration of about 1.5% by weight or less. Is preferably used. Further, in order to remove unnecessary developing solution after development, it is preferable to conduct the acid treatment or acid neutralization.

Then, the substrate on which the pattern is developed is fired to form a conductor pattern. Firing conditions can be about 400-600 degreeC, for example in air atmosphere or nitrogen atmosphere. At this time, it is preferable to set the temperature increase rate to 20 degrees C / min or less.

<Examples>

Hereinafter, although an Example and a comparative example are given and this embodiment is demonstrated concretely, this invention is not limited to these Examples.

(Synthesis of Organic Binder)

Methyl methacrylate and methacrylic acid were charged to a flask equipped with a thermometer, a stirrer, a dropping lot, and a reflux condenser at a molar ratio of 0.76: 0.24, and dipropylene glycol monomethyl ether as a solvent and azobisisobutyronitrile as a catalyst. It put, and stirred at 80 degreeC for 2 to 6 hours in nitrogen atmosphere, and obtained the resin solution.

The resin solution was cooled, and glycidyl methacrylate was used at 95 to 105 캜 for 16 hours using methylhydroquinone as a polymerization inhibitor and tetrabutylphosphonium bromide as a catalyst. The reaction was carried out at an addition molar ratio of 0.12 mol relative to, and after cooling, the organic binder A was taken out.

The organic binder obtained 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 measurement of a weight average molecular weight measures pump LC-6AD (made by Shimadzu Corporation) and column Shodex (trademark) KF-804, KF-803, and KF-802 (made by Showa Denko). It measured by the high speed liquid chromatography which connected three.

(Production of Glass Slurry)

50 mass parts of glass frits of (F-1)-(F-4) shown in following Table 1, 49 mass parts of organic solvents, and 1 mass part of dispersing agents are mixed, and this is wet-dispersed by the bead mill, and it shows in Table 1 The glass slurry containing the glass frit of the average particle diameter (D50) shown was produced.

Using the organic binder A and the said glass slurry or glass frit (F-5), each component was mix | blended in the composition ratio shown to Tables 2 and 3 below, stirred with a stirrer, and then ground by a triaxial roll mill to paste into paste. And photosensitive conductive pastes of Examples 1 to 5 and Comparative Examples 1 to 5 were prepared. In addition, Table 2 shows that the parameter of the silver powder was changed, and Table 3 shows the parameter of the glass frit was changed.

* 1: CA Carbitol Acetate (manufactured by Dow Chemical Co., Ltd.)

* 2: TMPTA trimethylolpropane triacrylate (manufactured by Nippon Kayaku)

* 3: Irg 369 (made by Chiba Japan)

* 4: Modaflow (Monsanto Chemical Co., Ltd.)

* 5: P-1M (Kyoeisha Chemical Co., Ltd.)

In addition, the average particle diameter of the glass frit was measured by the Horiba laser diffraction / scattering particle size distribution analyzer LA-920.

The test piece was produced using each photosensitive electrically conductive paste manufactured in this way.

(Test piece production)

Each photosensitive electrically conductive paste was apply | coated to the whole surface using the 200-mesh polyester screen on the glass substrate, and it dried for 20 minutes at 100 degreeC in IR drying furnace, and formed the dry coating film.

Subsequently, using a short arc lamp as a light source, pattern exposure so that the accumulated light amount on a dry coating film might be 300 mJ / cm <2> through a negative mask, image development was performed using the 0.4 weight% sodium carbonate aqueous solution, and it washed with water.

Thus, the board | substrate with a pattern was baked at 590 degreeC for 10 minutes in air atmosphere at the temperature increase rate of 14 degreeC / min, and the test piece in which the conductor pattern for each evaluation was formed was produced.

Evaluation was performed as follows using each test piece manufactured in this way.

(Film thickness)

The film thickness of the conductor pattern in each test piece was measured using the surface roughness meter (SE700, manufactured by Kosaka Shosho).

(Density)

About the conductor pattern of 300 micrometers of line widths in each test piece, the conductor pattern was observed by the optical microscope (STM5-MJS, Olympus company) at the magnification 500 using the transmitted light, and the density was evaluated. The evaluation criteria are as follows.

Dense: The conductor pattern is made dense and uniform.

Roughness: The conductor pattern is sparse and uneven.

(Resistance value)

The resistance value and the film thickness in the line pattern of 0.4x10 cm were measured, and the specific resistance value was computed. The specific resistance value was measured by a myriam under tester (HIOKI 3540 mΩ, manufactured by Hioki Co., Ltd.).

These evaluation results are shown in Tables 4 and 5 below.

From Examples 1 to 5 shown in Tables 4 and 5, it can be seen that by using the photosensitive conductive paste of the present embodiment, a conductor pattern of a thin film having good density and specific resistance can be formed.

On the other hand, in the comparative examples 1 and 2 which do not satisfy | fill the conditions of the silver powder of this embodiment, it turns out that favorable density and a specific resistance value are not obtained. Moreover, it turns out that favorable compactness is not obtained in the comparative examples 3 and 4 whose softening point of a glass frit is out of the range of this embodiment. In addition, in the comparative example 5 in which the relative ratio of glass frit is large, it turns out that a favorable specific resistance value is not obtained.

Claims (6)

As a photosensitive electrically conductive paste containing an organic binder, silver powder, a photopolymerization monomer, a photoinitiator, an organic solvent, and a glass frit,
The silver powder satisfies a primary particle size of 0.7 μm or less, a specific surface area of 1.4 to 2.0 m 2 / g, and a tap density of 2.0 to 5.0 g / cm 3, and contains 15% by mass to 35% by mass of the photosensitive conductive paste.
The glass frit has an average particle diameter (D50) of 0.3 to 1.5 µm and a softening point of 530 to 650 ° C. The photosensitive conductive paste according to claim 1, wherein the content of the glass frit is 0.01 to 35 parts by mass with respect to 100 parts by mass of the silver powder. It formed using the photosensitive electrically conductive paste of Claim 1 or 2, The conductor pattern characterized by the above-mentioned. The conductor pattern according to claim 3, wherein the content of the glass frit in the conductor pattern is 0.01 to 35 parts by mass with respect to 100 parts by mass of the silver powder. The conductor pattern according to claim 3, wherein the thickness of the conductor pattern is 1.2 µm or less. The conductor pattern of Claim 3 is provided, The plasma display panel characterized by the above-mentioned.