KR20130111314A - Conductive paste and conductive circuit - Google Patents

Abstract

PURPOSE: A conductive paste is provided to obtain a conductive circuit with low resistance and to improve the resolution of a conductive circuit together with photosensitivity. CONSTITUTION: A conductive paste contains conductive powder, an organic binder, and at least one of thiodiglycolic acid and derivatives thereof. The conductive powder includes silver powder. The amount of the one of the thioglycolic acid and derivatives thereof used is 0.01-10 parts by weight per 100 parts by weight of the organic binder in a solid phase. The conductive paste is photosensitive or non-photosensitive. A photosensitive conductive paste additionally contains a photopolymerization initiator.

Description

Conductive Paste and Conductive Circuits {CONDUCTIVE PASTE AND CONDUCTIVE CIRCUIT}

The present invention relates to a conductive paste and a conductive circuit using the same.

Conventionally, as a technique for forming a conductive circuit for a flat panel display (hereinafter also referred to as "FPD") such as a plasma display panel (hereinafter also referred to as "PDP"), a conductive paste obtained by mixing conductive powder such as silver powder with an organic binder is used. An organic component is formed on a substrate by, for example, a method using a printing technique such as screen printing, or a method using a photolithography technique using a conductive paste imparting photosensitivity, and then firing at 550 ° C. or higher for the organic component. It is known to burn out and to form a conductive circuit composed of only inorganic components by fusing the conductive powder onto a substrate (see Patent Documents 1 and 2, for example). However, since this method is performed at very high temperature conditions, the applicable substrate is limited.

In contrast, as a technique for forming a conductive circuit for a flexible device such as electronic paper using PET or the like for a substrate, or a device having low heat resistance such as a touch panel, a conductive paste is pattern-formed on the substrate to form a temperature of 250 ° C. or lower. The method of hardening | curing and forming the electrically conductive circuit containing an electroconductive powder and an organic component is proposed (for example, refer patent document 3 etc.).

In order to obtain high conductivity in the conductive circuit formed of these conductive pastes, for example, the content of the conductive powder in the conductive paste is increased, or the shape such as flake-like conductive powder is examined to examine the low resistance of the conductive circuit. Although anger is planned, there is still room for improvement as it is not enough.

On the other hand, the demand for miniaturization, high density, high precision, etc. is increasing in FPDs such as a multilayer circuit board for mounting a large number of highly integrated LSIs and various electronic components, or PDPs. It is even more demanding.

With respect to such a demand, a photolithography method which is capable of achieving high precision of a conductive circuit in comparison with a screen printing method is preferable. In the photolithography method, however, the conductive powder hardly sufficiently hardens to the inside (deep portion) There is a problem in that diffusion of the radicals or active species generated in the reaction proceeds and the resolution of the conductive circuit is deteriorated.

Japanese Patent Laid-Open No. 10-269848 (claims, etc.) Japanese Patent No. 3520798 Japanese Patent Laid-Open No. 2004-355933 (patent claims, etc.)

This invention is made | formed in order to solve the said subject, The objective is to provide the electrically conductive paste which can form the electrically conductive circuit of low resistance. Moreover, it is providing the electrically conductive paste which provided the said photosensitive property and which can achieve high resolution of an electrically conductive circuit as a electrically conductive paste which provided the photosensitivity.

The electrically conductive paste which concerns on this embodiment contains an electroconductive powder, an organic binder, and at least 1 sort (s) of a thiodiglycolic acid and a thiodiglycolic acid derivative. It is characterized by the above-mentioned. This configuration can achieve lower resistance of the conductive circuit. Particularly, in a conductive circuit which does not burn out the organic component, a low resistance which can not be achieved conventionally can be achieved.

As a preferable aspect of the electrically conductive paste which concerns on this embodiment, it is preferable that the said electroconductive powder is silver powder. Moreover, it is preferable that the compounding quantity of at least 1 sort (s) of the said thioglycolic acid and the thioglycolic acid derivative is 0.01-10 mass parts per 100 mass parts of said organic binder resins in solid content conversion in the electrically conductive paste which concerns on this embodiment. Such a configuration can achieve further low resistance of the conductive circuit.

Moreover, the electrically conductive paste which concerns on this embodiment is characterized by containing a photopolymerizable monomer and an oxime ester system photoinitiator in addition to the said structure. With such a configuration, it is possible to achieve a low resistance of the obtained conductive circuit and to achieve high resolution.

Moreover, the electrically conductive circuit which concerns on this embodiment is formed using the above electrically conductive paste, It is characterized by the above-mentioned.

According to the electrically conductive paste which concerns on this invention, the electrically conductive circuit of low resistance can be formed. In addition, in the electrically conductive paste which provided the photosensitivity, while providing the said characteristic, high resolution of a conductive circuit can be achieved.

As a result of earnestly examining the above subjects, the inventors of the present invention have a low resistance by containing at least one of a conductive powder, an organic binder, and a thiodiglycolic acid and a thiodiglycolic acid derivative in a paste used for forming a conductive circuit. When it was found that the conductive circuit can be formed, and the photosensitive property is imparted to the paste, by containing an oxime ester photopolymerization initiator as the photopolymerization initiator, the inventors have found that not only the low resistance but also the high resolution of the conductive circuit obtained can be achieved. The present invention has been completed.

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

The electroconductive powder in the electrically conductive paste of this embodiment gives electroconductivity to the formed electrically conductive circuit, Specifically, For example, Ag, Au, Pt, Pd, Ni, Cu, Al, Sn, Pb, Zn, Fe, Ir, Os, Rh, W, Mo, Ru, etc. are mentioned. These conductive powders may be used in the form of a single body, or may be an alloy of any of these, or a multilayer body having any of these as a core or a coating layer. Oxides such as tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ ), and ITO (indium tin oxide) may also be used. Ag is preferably used among these electroconductive powders.

As a shape of electroconductive powder, in addition to a spherical shape and a flake (flake shape) shape, various shapes, such as a dendrite shape, can be used, It does not specifically limit.

Although there is no restriction | limiting in particular as particle size of electroconductive powder, For example, when using spherical electroconductive powder, an average particle diameter is 0.1-5 micrometers, Preferably it is 0.2-3 micrometers. In addition, when using flake shaped electroconductive powder, an average particle diameter is 0.1-5 micrometers, Preferably it is 0.3-3 micrometers.

In addition, an average particle diameter is calculated | required by measuring ten random electroconductive powders observed using SEM (scanning electron microscope), and calculating an average.

In addition, a flake silver powder means the silver powder which an aspect ratio is three or more specifically. Aspect ratio can be calculated | required by (average particle diameter / average thickness T).

Here, "average particle diameter" shows the average long diameter L of ten particles measured in the longitudinal direction with the scanning electron microscope, and "average thickness T" shows the average thickness T of ten particles measured with the scanning electron microscope in the thickness direction. Indicates.

It is preferable that such an electroconductive powder is 30-90 mass% based on the non volatile component of a electrically conductive paste (component which does not volatilize from the paste in a drying process, and remains in a film | membrane). If it is less than 30 mass%, it will become difficult to obtain sufficient electroconductivity, and if it exceeds 90 mass%, printability will fall and it becomes difficult to form a coating film. In addition, when the electrically conductive paste is photosensitive, since the light at the time of exposure does not permeate | transmit to a coating film core part, the photocurability of a core part deteriorates and formation of a thin wire pattern becomes impossible. More preferably, it is 50-85 mass%.

The organic binder in the electrically conductive paste of this embodiment is used in order to form a pattern in a coating film by developing by pattern exposure, when the electrically conductive paste disperse | distributes electroconductive powder and makes it applyable on a board | substrate, and when a electrically conductive paste is photosensitive. .

As the organic binder, any of a non-photosensitive resin and a photosensitive resin can be used. As an organic binder, what contains any 1 type of a dry organic binder, a thermosetting organic binder, and a photocurable organic binder can be used. It does not necessarily need to be used in a group, and can also use 2 or more types together.

Among these, a dry organic binder and a thermosetting organic binder are used for a non-photosensitive electrically conductive paste. A dry organic binder is used together with the organic solvent mentioned later, and an organic solvent is removed by heat drying, and a dry coating film is formed. In addition, the thermosetting organic binder is cured by crosslinking between molecules under the action of heat or a catalyst to form a cured coating film.

Such dry organic binders and thermosetting organic binders include olefinic hydroxyl group-containing polymers such as acrylic polyols, polyvinyl alcohols, polyvinyl acetals, styrene-allyl alcohol resins, and phenol resins, methyl cellulose, ethyl cellulose, and hydroxyethyl cellulose. Cellulose derivatives such as ethylene, vinyl acetate copolymers, alkyd resins, alkydphenol resins, butyral resins, epoxy resins, modified epoxy resins, acrylic resins, polyurethane resins, polyester resins and the like can be used. In particular, when forming a cured coating film by thermosetting as a thermosetting organic binder, it is preferable to use together the thermal polymerization catalyst of a peroxide mentioned later.

In addition, a photocurable organic binder is used when providing photosensitivity, and it hardens by intermolecular crosslinking under the action of active energy rays, such as an ultraviolet-ray and an electron beam, and forms a cured coating film.

As such a photocurable organic binder, resin which has ethylenically unsaturated bonds, such as a vinyl group, an allyl group, acryloyl group, and methacryloyl group, and photosensitive groups, such as a propargyl group, for example, an acryl type which has an ethylenically unsaturated group in a side chain Various conventionally well-known photosensitive resins (photosensitive prepolymers), such as a copolymer, unsaturated carboxylic acid modified epoxy resin, or resin which added polybasic acid anhydride to it, can be used.

These photocurable organic binders can be used in combination with the compound which has 1 or more ethylenically unsaturated bond in a molecule | numerator, ie, the photopolymerizable monomer mentioned later. In addition, in order for a photocurable organic binder to advance photopolymerization more efficiently, it is preferable to use together the photoinitiator mentioned later.

When using for the photolithographic method, resin which has a carboxyl group is especially preferable among the said resin etc. from a developable viewpoint. As resin (which may be any of an oligomer and a polymer) which has such a carboxyl group, the following are mentioned specifically ,, for example.

(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) Ethylenic by glycidyl (meth) acrylate, (meth) acrylic acid chloride, etc. in the copolymer of unsaturated carboxylic acids, such as (meth) acrylic acid, and a compound which has unsaturated double bonds, such as methyl (meth) acrylate, etc. Carboxyl group containing photosensitive resin obtained by adding an 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 and not having an ethylenically unsaturated bond is reacted with an epoxy group of a compound having an unsaturated double bond such as methyl (meth) acrylate and a copolymer of glycidyl (meth) acrylate. The carboxyl group-containing photosensitive resin obtained by making polyhydric anhydride react with the produced | generated secondary hydroxyl group.

(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 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, these resin can be used individually or in mixture. In addition, in this specification, a (meth) acrylate is a term which generically mentions acrylate, methacrylate, and mixtures thereof, and the same also about other similar expression.

As a compounding quantity of resin which has such a carboxyl group, it is preferable to mix | blend at 1-50 mass% based on a non volatile component (component which does not volatilize in a paste in a drying process, and remains in a film | membrane). When it is less than 1 mass%, developability will deteriorate significantly by lack of these resin in the coating film to form, and patterning by image development will become difficult. On the other hand, when it exceeds 50 mass%, the ratio of electroconductive powder runs short and there exists a tendency for a resistance value to deteriorate.

Moreover, as a weight average molecular weight, it is preferable that it is 1,000-100,000. When the weight average molecular weight is less than 1,000, the adhesiveness of the coating film at the time of development deteriorates, and when it exceeds 100,000, it becomes easy to produce developing defects. More preferably, it is 5,000-70,000. In addition, a weight average molecular weight is the value of polystyrene conversion measured by gel permeation chromatography (GPC).

Moreover, it is preferable that the acid value of resin which has a carboxyl group 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 / eq. When the double bond equivalent of carboxyl group-containing photosensitive resin is less than 350 g / eq, a pattern becomes easy to be thick and the sharpness of a line tends to deteriorate. On the other hand, when it exceeds 2,000 g / eq, the working 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 / eq.

Thiodiglycolic acid is added for imparting stability of a metal plating solution. In this embodiment mode, formation of a low-resistance conductive circuit can be achieved by containing it in a conductive paste used for forming a conductive circuit. In addition, when providing photosensitivity to a electrically conductive paste, by using together with the oxime ester system photoinitiator mentioned later, not only the low resistance of the said electrically conductive circuit but high resolution can be achieved. As the thiodiglycolic acid, thiodiglycolic acid such as CICA (Chemicals, Industrial products, Collect, Associate) grade 1 manufactured by Kanto Chemical Co., Ltd. can be used.

In addition, the above-described conductive circuit can also be formed by using a thiodiglycolic acid derivative. In addition, a derivative means the compound produced by the small change in the structure of a certain compound, and generally refers to the compound in which the hydrogen atom or the specific atomic group of the compound was substituted by the other atom or atomic group.

Examples of the thiodiglycolic acid derivative include 3,3'-thiodipropionic acid, thiodiacetate diallyl, thiobis (butyl acetate), disothiothioglycolate, and 2,2'-thiodiacetic acid bis ( 2-ethylhexyl), thiodioctyl acetate, 2,2'- thiobis (methyl acetate), the dithiodi glycolate potassium etc. are mentioned.

The blending ratio of at least one of the thiodiglycolic acid and the thiodiglycolic acid derivative is preferably from 0.01 to 10 parts by mass per 100 parts by mass of the organic binder in terms of solid content. If it is less than 0.01 mass part, electroconductivity will deteriorate. On the other hand, when it exceeds 10 mass parts, electroconductivity will deteriorate similarly, and patterning property will deteriorate by the characteristic of at least any 1 type of thioglycolic acid and the derivative of thioglycolic acid which are very developable. More preferably, it is 0.1-5 mass parts.

In addition, when providing photosensitive property to the electrically conductive paste of this embodiment, a photopolymerizable monomer can be used.

Examples of the photopolymerizable monomer include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, and polyurethane diacrylate. , Trimethylol propane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, trimethylol propane 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 Can be.

These photopolymerizable monomers can be used individually or in combination of 2 or more types. Moreover, the polyfunctional monomer which has two or more acryloyl group or a methacryloyl group in 1 molecule among these photopolymerizable monomers is preferable.

As a compounding quantity of such a photopolymerizable monomer, 5-200 mass parts is preferable per 100 mass parts of organic binders in conversion of solid content.

In addition, when providing photosensitive property to a conductive paste, a photoinitiator can be used for the purpose of promoting photocuring.

As a photoinitiator, For 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 jade Phosphine oxides such as seeds and ethyl-2,4,6-trimethylbenzoyldiphenylphosphinate; Various peroxides are mentioned.

As a commercial item, for example, Irgacure (IRGACURE) 184, Irgacure 819, Irgacure 907, Irgacure 369, Irgacure 379, Irgacure 389, Lucirin (registered trademark) made by BASF Japan ) TPO and the like.

As a compounding quantity of a photoinitiator, 0.01-50 mass parts is preferable per 100 mass parts of organic binders in conversion of solid content. If it is less than 0.01 mass part, photocurability will become inadequate and a shift | offset | difference will arise easily in a pattern. In addition, the surface curability is insufficient, and the surface of the coating film is damaged at the time of development, thereby affecting the conductivity. On the other hand, when 50 mass parts is exceeded, the pattern will halt, and the sharpness of a pattern edge part will deteriorate. In addition, the pattern's extractability is deteriorated, and a pattern with a small space cannot be drawn.

Among the photoinitiators, in particular, the oxime ester photoinitiator has a high photosensitivity, and therefore even a paste containing a large amount of conductive powder can be sufficiently cured with a small exposure amount, thereby forming a conductive circuit having high resolution.

As an oxime ester system photoinitiator, For example, the compound which has group represented by following General formula (I),

(Wherein R ¹ is a hydrogen atom, a phenyl group (may be substituted with an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom), an alkyl group having 1 to 20 carbon atoms (may be substituted with one or more hydroxyl groups, the middle of the alkyl chain) May have one or more oxygen atoms), a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms, or a benzoyl group (which may be substituted with an alkyl group having 1 to 6 carbon atoms or a phenyl group), R ² may be substituted with a phenyl group (which may be substituted with an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom), an alkyl group having 1 to 20 carbon atoms (which may be substituted with one or more hydroxyl groups, and at least one oxygen atom in the middle of the alkyl chain; Or a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms, or a benzoyl group (which may be substituted with an alkyl group having 1 to 6 carbon atoms or a phenyl group)

2- (acetyloxyiminomethyl) thioxanthene-9-one represented by the following formula (II),

A compound represented by the following formula (III),

(Wherein, R ³ and R ⁴ each independently represent an alkyl group having 1 to 12 carbon atoms, M represents S, O or NH, and R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently Hydrogen atom or an alkyl group having 1 to 6 carbon atoms, m and n represent an integer of 0 to 5)

A compound represented by the following formula (IV),

(In formula, R <^10> is a hydrogen atom, a halogen atom, a C1-C12 alkyl group, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, a C2-C12 alkanoyl group, a C2-C12 thing. An alkoxycarbonyl group (when the alkyl group constituting the alkoxyl group has 2 or more carbon atoms, the alkyl group may be substituted with one or more hydroxyl groups and may have one or more oxygen atoms in the middle of the alkyl chain), or a phenoxycarbonyl group , R ¹¹ , R ¹³ are each independently a phenyl group (may be substituted with an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom), an alkyl group having 1 to 20 carbon atoms (may be substituted with one or more hydroxyl groups, and in the middle of the alkyl chain May have one or more oxygen atoms), a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms, or a benzoyl group (alkyl group having 1 to 6 carbon atoms or phenyl group) Represents May hwandoel), R ¹² may be substituted with a hydrogen atom, a phenyl group (alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom may be substituted), a hydroxyl group (at least one C 1 -C 20 alkyl May have one or more oxygen atoms in the middle of the chain), a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms, or a benzoyl group (may be substituted with an alkyl group having 1 to 6 carbon atoms or a phenyl group) Indicates

The compound represented by the following general formula (V),

(In formula, R <^14> represents a C1-C20 alkyl group, a C6-C30 aryl group, a C7-C30 arylalkyl group, or CN, and the hydrogen atom of an alkyl group, an aryl group, and an arylalkyl group is further OR <^41> , COR ⁴¹ , SR ⁴¹ , NR ⁴² R ⁴³ , -NCOR ⁴² -OCOR ⁴³ , CN, a halogen atom, -CR ⁴¹ = CR ⁴² R ⁴³ or CO-CR ⁴¹ = CR ⁴² R ⁴³ , and may be substituted with R ⁴¹ , R ⁴² and R ⁴³ each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, or a heterocyclic group having 2 to 20 carbon atoms, and R ¹⁵ is R ⁵¹ Or OR ⁵¹ , R ⁵¹ represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an arylalkyl group having 7 to 30 carbon atoms, and the hydrogen atoms of the alkyl group, aryl group and arylalkyl group are further substituted with halogen atoms. may be, R ¹⁶ is an alkyl group having 1 to 20 carbon atoms, having 6 to 30 carbon atoms An aryl group, or an aryl alkyl group having 7 to ^{30, R 14, R 16,} R 41, R 42 and R ⁴³ alkylene methylene group unsaturation of the portion of the substituent represented by the ether bond, a thioether bond, an ester bond May be interrupted 1 to 5 times by a thioester bond, an amide bond or a urethane bond, the alkyl moiety of the substituent may be a branched side chain, a cyclic alkyl, or the alkyl terminal of the substituent may be an unsaturated bond. And R ¹⁶ may be combined with an adjacent benzene ring to form a ring, R ¹⁷ and R ¹⁸ each independently represent R ⁵¹ , OR ⁵¹ , CN or a halogen atom, and a and b each independently represent 0 to 3 being),

The compound which has carbazole dimer represented by the following general formula (VI) can be used.

(In formula, R <^19> is a hydrogen atom, a C1-C17 alkyl group, a C1-C8 alkoxy group, a phenyl group, a phenyl group (C1-C17 alkyl group, a C1-C8 alkoxy group, an amino group, C1-C8). Substituted by an alkylamino or dialkylamino group having an alkyl group of 1), a naphthyl group (an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an amino group, an alkylamino group having 1 to 8 carbon atoms or a dialkyl group) R ²⁰ and R ²¹ each represent a hydrogen atom, an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a halogen group, a phenyl group, and a phenyl group (alkyl group having 1 to 17 carbon atoms) Substituted by an alkylamino group or dialkylamino group having 1 to 8 alkoxy groups, amino groups, alkyl groups having 1 to 8 carbon atoms, naphthyl groups (alkyl groups having 1 to 17 carbon atoms, and carbon atoms) And an alkyl group having 1 to 8 alkoxy, an amino group, an alkylamino group having 1 to 8 carbon atoms or a dialkylamino group), an anthryl group, a pyridyl group, a benzofuryl group, a benzothienyl group, and Ar represents a carbon number 1-10 alkylene, vinylene, phenylene, biphenylene, pyridylene, naphthylene, anthylene, thienylene, furylene, 2,5-pyrrole-diyl, 4,4'-stilbene-diyl , 4,2'-styrene-diyl, n is an integer of 0 or 1)

As a commercial item, CGI-325 by the BASF Japan company, Irgacure (registered trademark) OXE01, Irgacure OXE02, NCI-831 by Adeka Corporation, etc. can be used, for example.

As for the compounding quantity of an oxime ester system photoinitiator, as for solid content conversion, 0.01-30 mass parts is preferable per 100 mass parts of organic binders. If it is less than 0.01 mass part, similarly to the photoinitiator mentioned above, photocurability will become inadequate and defects will arise easily in a pattern. In addition, the surface curability is insufficient, and the surface of the coating film is damaged during development, resulting in deterioration of the resistance value. On the other hand, when it exceeds 30 mass parts, the pattern halation generate | occur | produces similarly to the photoinitiator mentioned above, and the sharpness of a pattern edge part deteriorates. In addition, the pattern's extractability is deteriorated, and a pattern with a small space cannot be drawn. More preferably, it is 0.05-5 mass parts.

The photoinitiator described above includes 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.

Moreover, a thermal polymerization catalyst can be used as needed for the purpose of accelerating hardening of an electrically conductive paste. The thermal polymerization catalyst can react the uncured polymerizable component by aging at a high temperature of several minutes to one hour.

Examples of such thermal polymerization catalysts include azo compounds such as peroxides such as benzoyl peroxide and isobutyronitrile, and preferably 2,2'-azobisisobutyronitrile and 2,2'-azobis-2. -Methylbutyronitrile, 2,2'-azobis-2,4-divaleronitrile, 1,1'-azobis-1-cyclohexanecarbonitrile, dimethyl-2,2'-azobisisobutylate , 4,4'-azobis-4-cyanovaleric acid, 2-methyl-2,2'-azobispropanenitrile, 2,4-dimethyl-2,2,2 ', 2'-azobispentane Nitrile, 1,1'-azobis (1-acetoxy-1-phenylethane), 2,2,2 ', 2'-azobis (2-methylbutanamide oxime) dihydrochloride, and the like.

In addition, an organic solvent can be used for the electrically conductive paste of this embodiment in order to adjust a viscosity and to form a uniform coating film.

As such an organic solvent, For example, ketones, such as methyl ethyl ketone and cyclohexanone; 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.

In such a conductive paste, a stabilizer can be further added in order to improve storage stability and to suppress deterioration of coating workability due to gelation or deterioration of fluidity.

As such a stabilizer, a compound having an effect such as complexing with conductive powder or salt formation in the 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. These stabilizers can be used individually or in combination of 2 or more types.

Moreover, other additives, such as a defoaming and 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 with the electrically conductive paste of this embodiment. Moreover, a well-known antioxidant, the thermal polymerization inhibitor, etc. for improving the thermal stability at the time of storage can also be added.

The electrically conductive paste comprised as mentioned above is manufactured by mixing each component, and can be hardened and pasted by a triaxial roll mill etc. after stirring with a stirrer etc.

As for the electrically conductive paste manufactured in this way, in the case of a non-photosensitive electrically conductive paste, a desired conductive circuit is printed on base materials, such as a glass substrate, by printing methods, such as screen printing and offset printing, and the base material with which the conductive circuit was printed after that The desired conductive circuit is formed on the substrate by drying or curing at 80 to 300 ° C. for 5 to 60 minutes.

On the other hand, in the case of the photosensitive electrically conductive paste, a electrically conductive circuit is formed by the following methods other than the said method.

First, it is apply | coated to base materials, such as a glass substrate, by appropriate coating methods, such as a screen printing method, a bar coater, and a blade coater, and a coating film is formed.

Subsequently, the obtained coating film is dried in a hot air circulation drying furnace, a far-infrared drying furnace, or the like for about 5 to 40 minutes, for example, at about 70 to 120 ° C. in order to obtain the touch drying property, thereby forming a tack free coating film (dry coating film). At this time, when electrically conductive paste is formed into a film in advance, you may laminate on a base material.

Then, selective exposure is performed to the obtained dry coating film. As selective exposure, contact exposure and non-contact exposure using the negative mask which has a predetermined exposure pattern are possible. As an exposure light source, a halogen lamp, a high pressure mercury lamp, a laser beam, a metal halide lamp, a black lamp, an electrodeless lamp etc. are used, for example. As an exposure amount, about 10-700 mJ / cm <2> is preferable.

Development is performed on the coating film after selective exposure. Spraying, dipping and the like are used for the development. As a developing solution, the carboxyl group contained in the organic binder contained in an electrically conductive paste may saponify, and what is necessary is just to be able to remove an uncured part (unexposed part), For example, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium silicate, etc. Aqueous metal alkali aqueous solution, aqueous amine solutions, such as monoethanolamine, diethanolamine, and triethanolamine, especially the aqueous alkali solution of the density | concentration of about 1.5 weight% or less are used preferably. In addition, it is preferable to perform washing with water or acid neutralization in order to remove unnecessary developer after development.

Thereafter, a desired conductive circuit is formed on the substrate by drying or curing the substrate on which the desired conductive pattern is formed by development at 80 to 300 ° C. for 5 to 60 minutes.

[Example]

Hereinafter, although an Example and a comparative example are given and this embodiment is demonstrated concretely, this invention is not limited to these Examples. In addition, below "%" is a basis of all unless there is particular notice.

<Synthesis example of organic binder resin solution>

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 0.87: 0.13, dipropylene glycol monomethyl ether as a solvent, and azobisisobutyronitrile as a catalyst. It put, and it stirred at 80 degreeC for 2 to 6 hours in nitrogen atmosphere, and obtained the resin solution containing an organic binder. This organic binder had a weight average molecular weight of about 10,000, an acid value of 74 mgKOH / g, and a solid content of 57%.

In addition, for the measurement of the weight average molecular weight of an organic binder, the high speed which connected Shimazu Seisakusho pump LC-6AD and Showa Denko column Shodex (trademark) KF-804, KF-803, and KF-802 three was carried out. Liquid chromatography was used.

[Conductive Paste]

<Production of Conductive Paste>

After mix | blending with each component and composition ratio shown in following Table 1, stirring with a stirrer, it was ground by the triaxial roll mill and pasteurized, and each electrically conductive paste of Examples 1-3 and Comparative Examples 1-4 was manufactured.

<Resistance resistance evaluation>

Each prepared conductive paste was pattern printed on a glass substrate to form a pattern of 0.4 cm x 10 cm, and heat-treated at 170 ° C x 30 minutes to form a conductive circuit of 0.4 cm x 10 cm. About this electrically conductive circuit, sheet resistance value was measured by the four-terminal method using a milliohm high tester, and the specific resistance value was computed.

* 1: average particle diameter = 1.5 mu m

* 2: 2,2'- thiodiglycolic acid (manufactured by Kanto Chemical Co., Ltd .; standard CICA Grade 1)

* 3: 3,3'- thiodipropionic acid (Kanto Chemical Co., Ltd .; standard CICA 1st class)

* 4: glycolic acid (manufactured by Kanto Chemical Co., Ltd .; standard CICA Grade 1)

* 5: Thioglycolic acid (manufactured by Kanto Chemical Co., Ltd .; standard CICA Grade 1)

* 6: malonic acid (manufactured by Kanto Chemical Co., Ltd .; standard CICA Grade 1)

* 7: BYK-354 (manufactured by Big Chemi Japan Co., Ltd.)

As shown in Table 1, in Examples 1 to 3 using thiodiglycolic acid or derivatives thereof, the specific resistance values of 10 ⁻⁵ (Ω · cm) orders were all obtained, and it was confirmed that the resistance was low. On the other hand, in place of at least one of Comparative Example 1, a thiodiglycolic acid and a thiodiglycolic acid derivative, which does not use at least one of thiodiglycolic acid and thiodiglycolic acid derivatives, glycolic acid and thioglycolic acid In Comparative Examples 2, 3, and 4 using malonic acid, respectively, the specific resistance values of 10 ⁻⁵ (Ω · cm) orders were not obtained, and it was confirmed that the specific resistance values were higher than those in Examples.

[Photosensitive conductive paste]

<Production of Photosensitive Conductive Paste>

After mix | blending with each component and composition ratio shown in following Table 2, stirring with a stirrer, it was ground by the triaxial roll mill and pasteurized, and each photosensitive electrically conductive paste of Examples 4-6 and Comparative Example 5 was manufactured. In addition, the brightness L ^* value of the electroconductive powder used for the photosensitive electrically conductive paste is the value measured according to JIS standard Z8722.

* 1: silver powder; Brightness L ^* = 70, Average Particle Size = 2 μm

* 2: silver powder; Brightness L ^* = 58, average particle size = 1.5 μm

* 3: oxime ester type photoinitiator; NCI-831 (made by Adeca)

* 4: thioxanthone type photopolymerization initiator; Kayakure (KAYACURE) DETX-S (manufactured by Nippon Kayaku Co., Ltd.)

* 5: acetoaminophenone series polymerization initiator; Irgacure 379 (manufactured by BASF Japan)

* 6: 2,2'- thiodiglycolic acid (manufactured by Kanto Chemical Co., Ltd .; standard CICA Grade 1)

* 7: M-350 (manufactured by Toago Kosei Co., Ltd.)

* 8: Carbitol Acetate

* 9: BYK-354 (manufactured by Big Chemie Japan)

* 10: calculated on the basis of nonvolatile components

(Resolution evaluation)

Each photosensitive electrically conductive paste was apply | coated to the whole surface so that the wet film thickness might be set to 14 micrometers on the glass substrate using the 200-mesh polyester screen, and it dried for 20 minutes at 100 degreeC in IR drying furnace, and formed the dry coating film. In addition, the film thickness of the coating film after drying was 10 micrometers.

Next, the ultra-high pressure mercury lamp was used as a light source for the obtained dry coating film, and the resolution which remained through the negative mask used the straight line pattern negative mask of a line = 10/20 / -90 / 100 micrometer. As the extraction resolution, a negative / positive inverse pattern of the negative pattern of the remaining resolution was used. About each dry coating film, after pattern-exposure at 200 mJ / cm <2>, image development was performed with 10 and 20 second developing time using the 0.4% sodium carbonate aqueous solution of 30 degreeC of liquid temperature, and it washed with water.

Remaining resolution; Negative mask design value of minimum residual pattern.

Launch resolution; Negative mask design with minimal space patterned.

The measurement results are shown in Table 3 below.

(Resistance resistance evaluation)

The rectangular pattern of negative design 0.4 * 10 (cm) was formed, and the specific resistance value was computed from the resistance value and film thickness after thermosetting. The measurement results are shown in Table 3.

As shown in Table 3, it turns out that all the Examples 4, 5, and 6 which used the photosensitive electrically conductive paste of this embodiment which used thioglycolic acid have low resistance compared with the comparative example 5 which does not use thioglycolic acid. In addition, in Examples 4 and 5 using the oxime ester system as the photopolymerization initiator, it can be seen that in addition to being low resistance, the remaining resolution and the extraction resolution are better than those in Example 6 in which the oxime ester system is not used as the photopolymerization initiator. . In addition, it is understood from the results of Examples 4 and 5 that the photosensitive conductive paste of the present embodiment has good patterning regardless of the brightness L ^* value of the conductive powder.

Claims (9)

A conductive paste containing at least any one of an electroconductive powder, an organic binder, and a thiodiglycolic acid and a thiodiglycolic acid derivative. The conductive paste of claim 1, wherein the conductive powder comprises silver powder. The conductive paste according to claim 1, wherein at least one of the thiodiglycolic acid and the thiodiglycolic acid derivative is 0.01 to 10 parts by mass per 100 parts by mass of the organic binder in terms of solid content. The conductive paste according to any one of claims 1 to 3, which is non-photosensitive. The conductive paste according to any one of claims 1 to 3, which is photosensitive. The electrically conductive paste of Claim 5 containing a photoinitiator further. The electrically conductive paste of Claim 6 with which the said photoinitiator contains an oxime ester type photoinitiator. The electrically conductive paste of Claim 5 containing a photopolymerizable monomer further. It is formed using the electrically conductive paste of Claim 1, The electrically conductive circuit characterized by the above-mentioned.