CN103571275B - Conductive ink composition, the manufacture method of conductive pattern and electroconductive circuit - Google Patents

Abstract

The present invention provides a conductive ink composition having low viscosity and excellent printing adaptability, which can be cured at a lower temperature and shorter time, and which can obtain a high-conductivity and high-definition pattern, a method for producing a conductive pattern, and a conductive circuit. The conductive ink composition is characterized in that the conductive ink composition contains a conductive filler, a thermosetting resin composition, and an organic solvent as essential components, and further contains a phosphoric acid group, a phosphate group, a phosphate ester An organic compound with at least one functional group selected from the group consisting of groups.

Description

Conductive ink composition, method for producing conductive pattern, and conductive circuit

technical field

The present invention relates to a conductive ink composition for forming a conductive film, a method for producing a conductive pattern, and a conductive circuit.

Background technique

A printing method or an etching method is known as a method for forming conductive patterns such as conductive circuits and electrodes used in touch panels, electronic paper, and various electronic components.

In the case of forming a conductive pattern by etching, after forming a patterned resist film by photolithography on a substrate on which various metal films have been deposited, it is necessary to chemically or electrochemically dissolve the unnecessary deposited metal film Remove, and finally remove the resist film, this process is very complicated and cannot be mass-produced.

On the other hand, a desired pattern can be mass-produced at low cost by the printing method, and conductivity can be easily imparted by drying or curing the printed coating film.

As these printing methods, flexographic printing, screen printing, gravure printing, gravure offset printing, inkjet, etc. are proposed depending on the line width, thickness, and production speed of the pattern to be formed.

As a printed pattern, it is required to form a high-definition conductive pattern with a line width of 50 μm or less from the viewpoint of miniaturization of electronic equipment, improvement of design, and the like.

In addition, in order to respond to the increased demand for thinner, lighter, and softer electronic devices, and roll-to-roll printing with high productivity, printing on plastic films is required, and high conductivity and substrates can be obtained by firing at low temperature and short time. Conductive ink for adhesion, film hardness, etc. Furthermore, among plastic films, it is required to be used on non-heat-resistant substrates such as PET (polyethylene terephthalate) film with low cost and high transparency, and transparent conductive film formed with ITO film on PET film. When printing, a conductive ink having the above physical properties can be obtained.

In such a case, various conductive ink compositions are known as heat-curable conductive paste compositions containing silver powder, a heat-curable (thermosetting resin composition) component, and a solvent. The above-mentioned heat-curable (thermosetting resin composition) Composition) components include blocked polyisocyanate compound and thermoplastic resin, the thermoplastic resin is at least one thermoplastic resin selected from the group consisting of epoxy resin, linear polyester resin and vinyl chloride vinyl acetate copolymer Resin (Patent Documents 1 to 6).

However, all of these conductive ink compositions have high viscosity and are not excellent in printability. In addition, in order to improve only the printability, a surfactant or the like may be added to the conductive ink composition, but in many cases, although the printability can be improved, the conductivity is conversely impaired.

Patent Document 1: Japanese Patent Laid-Open No. 2002-161123

Patent Document 2: Japanese Patent Laid-Open No. 2006-302825

Patent Document 3: JP 2009-26558

Patent Document 4: JP 2009-24066

Patent Document 5: JP 2012-38614

Patent Document 6: JP 2012-38615

Contents of the invention

The problem to be solved by the invention

The problem to be solved by the present invention is to provide a conductive ink composition having a low viscosity, excellent printing suitability, and a pattern having high conductivity.

method used to solve the problem

In order to solve the above-mentioned problems, the inventors of the present invention have conducted intensive studies and found that by including a compound having a phosphoric acid group in the conventional conductive ink composition, the high conductivity of the obtained conductive pattern will not be damaged even after thermal curing. The present invention has been completed by obtaining a conductive ink composition capable of forming a conductive pattern with low viscosity and excellent printing adaptability.

That is, the present invention provides a conductive ink composition, which is characterized in that it is a conductive ink composition containing a conductive filler, a thermosetting resin composition, and an organic solvent as essential components, and further contains An organic compound with at least one functional group selected from the group consisting of a group and a phosphate group.

In addition, the present invention provides a method for producing a conductive pattern, which comprises applying the above-mentioned conductive ink composition on a non-heat-resistant substrate and heating it.

Furthermore, the present invention provides a conductive circuit including a conductive pattern in which a cured film of the above-mentioned conductive ink composition is formed on a non-heat-resistant substrate.

The effect of the invention

Since the conductive ink composition of the present invention contains an organic compound having at least one functional group selected from the group consisting of a phosphoric acid group, a phosphate group, and a phosphoric ester group, low viscosity and printability can be achieved. Excellent such a particularly noticeable effect. Thereby, even when using non-heat-resistant base materials, such as a PET film, a highly conductive conductive pattern can be manufactured.

detailed description

(conductive filler)

As the conductive filler used in the present invention, known ones can be used. Examples include nickel, copper, gold, silver, aluminum, zinc, tin, lead, chromium, platinum, palladium, tungsten, molybdenum, etc., and alloys, mixtures, or compounds of two or more of these metals that have good electrical conductivity. Substance etc. In particular, silver powder is preferable because it can easily achieve stable electrical conductivity and also has good thermal conductivity.

(silver powder)

When silver powder is used as the conductive filler of the present invention, the average particle diameter is preferably spherical silver powder having a median diameter (D50) of 0.1 to 10 μm, more preferably 0.1 to 3 μm. Within this range, the fluidity of the conductive ink composition can be improved by using together with an organic compound containing at least one functional group selected from the group consisting of a phosphoric acid group, a phosphate group, and a phosphoric acid ester group. Greater effect, better fluidity, in certain printing methods such as flexographic printing, screen printing, gravure printing or gravure offset printing, it is easy to obtain difficult to break down, even when printing is performed continuously on these printing machines Stable and good conductive pattern.

Examples of such silver powders include AG2-1C (manufactured by DOWA Electronics Co., Ltd., average particle diameter D50: 0.8 μm), SPQ03S (manufactured by Mitsui Metal Mining Co., Ltd., average particle diameter D50: 0.5 μm), EHD ( Mitsui Metal Mining Co., Ltd., average particle size D50: 0.5 μm), SYLVESTER C-34 (manufactured by Tori Chemical Research Institute, average particle size D50: 0.35 μm), AG2-1 (DOWA Electronics Co., Ltd. ), average particle diameter D50: 1.3 μm), SYLVESTER AgS-050 (manufactured by Tori Chemical Research Institute, average particle diameter D50: 1.4 μm), etc.

The conductive filler may be a conductive filler formed by previously covering the surface with an organic compound containing at least one functional group selected from the group consisting of a phosphoric acid group, a phosphate group, and a phosphoric acid ester group, which will be described later.

In the conductive ink composition of the present invention, the ratio of the conductive filler to the thermosetting resin composition described later is not particularly limited, but from the viewpoint of the conductivity of the conductive pattern obtained, it is preferably calculated in terms of mass per 100 parts The conductive filler thermosetting resin composition is prepared in such a manner that it is 3 to 15 parts.

(thermosetting resin composition)

A thermosetting resin composition is used in the present invention. The so-called thermosetting resin composition is only a composition composed of a combination of an uncurable main ingredient and a curing agent. The main ingredient and curing agent are selected so that they do not react even if they are mixed at room temperature, and curing starts only when heated. As the main ingredient, a thermoplastic resin which itself has film-forming properties is often used because it is easy to obtain a high-definition conductive pattern. As such a thermosetting resin composition, for example, a combination of an epoxy compound as a main ingredient and an epoxy resin curing agent such as an acid anhydride, an amine, or a phenol resin, a hydroxyl-containing vinyl chloride-vinyl acetate resin as a main ingredient, A combination of a hydroxyl-containing film-forming thermoplastic resin such as a hydroxyl-containing polyester resin, a hydroxyl-containing acrylic resin, and an isocyanate curing agent such as blocked polyisocyanate. When preparing a thermosetting resin composition, the main ingredient and curing agent exemplified above may be used alone or in combination of two or more.

Examples of commercially available hydroxyl-containing film-forming thermoplastic resins include, for example, hydroxyl-containing vinyl chloride-vinyl acetate resins such as the SOLBIN series manufactured by Nissin Chemical Industry, and examples of hydroxyl-containing polyester resins include Toyobo Co., Ltd. Made BYRON series, etc.

In particular, a combination of a blocked polyisocyanate and a film-forming thermoplastic resin having a hydroxyl group is preferable, because the dispersibility of the conductive filler can be excellent, and if more of the combination is contained in the composition, the conductivity can be further improved as a result, and the The adhesiveness of the base material at the time of hardening is excellent. This adhesiveness is extremely advantageous in terms of improving the flexibility of electrical and electronic components provided with conductive circuits and enabling high integration when the object for forming the conductive pattern is a soft non-heat-resistant substrate.

(blocked polyisocyanate)

The blocked polyisocyanate used in the present invention, which thermally dissociates a blocking agent to generate free isocyanate groups, consists of a polyisocyanate compound and a blocking agent.

The type of polyisocyanate compound is not particularly limited, and may be aromatic, aliphatic, or cycloaliphatic diisocyanate, dimer or trimer obtained by modification of diisocyanate, compounds containing terminal isocyanate groups, and the like. They can be used alone or in combination. Examples of aromatic diisocyanate include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate , Dianisidine diisocyanate, etc. Examples of aliphatic diisocyanates include 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate (hereinafter HMDI), 2,2, 4-trimethyl-1,6-hexamethylene diisocyanate, etc. Examples of alicyclic diisocyanates include lysine diisocyanate, isophorone diisocyanate (hereinafter IPDI), 1,3-bis(isocyanatomethyl)-cyclohexane, 4,4'- Dicyclohexylmethane diisocyanate and the like, further 2- or 3-mers obtained by modifying these diisocyanates are exemplified. Examples of modification methods include biuretization, isocyanuration, and the like. Alternatively, the above di- or polyisocyanate compounds are reacted with active hydrogen compounds such as ethylene glycol, propylene glycol, trimethylolpropane, ethanolamine, polyester polyol, polyether polyol, polyamide, etc., which contain terminal isocyanate groups. compounds, etc.

Examples of the blocking agent include known and commonly used blocking agents such as phenol, methyl ethyl ketone oxime, and sodium bisulfite. When the conductive pattern formed by the conductive ink composition of the present invention is provided on a heat-resistant substrate such as glass, metal, silica, or ceramics, as these sealing agents, any substance can be used, but in the When it is installed on a non-heat-resistant substrate such as a PET film, a PP film, or a transparent ITO electrode film, it is preferable to use a blocked polyisocyanate that dissociates a blocking agent at a lower temperature to release isocyanate groups. In particular, when PET film is used as the plastic film on the substrate, as long as the conductive ink composition contains a blocked polyisocyanate compound using a blocking agent such that the temperature at which isocyanate groups are generated is 70 to 125°C, Then, no warping or the like occurs on the PET film, and a conductive pattern can be formed thereon.

Examples of such blocking agents capable of dissociation at lower temperatures include active methylene compounds and pyrazole compounds. Examples of active methylene compounds include isopropylidene malonate (meldrum's acid), dialkyl malonate, alkyl acetoacetate, ethyl methacrylate 2-acetoacetate, acetylacetone , ethyl cyanoacetate, etc., as the pyrazole compound, pyrazole, 3,5-dimethylpyrazole, 3-methylpyrazole, 4-benzyl-3,5-dimethylpyrazole, 4 -nitro-3,5-dimethylpyrazole, 4-bromo-3,5-dimethylpyrazole, 3-methyl-5-phenylpyrazole and the like. Among them, diethyl malonate, 3,5-dimethylpyrazole, and the like are preferable.

With regard to the blocked polyisocyanate compound that thermally dissociates the blocking agent to generate free isocyanate groups, it is possible to monitor the infrared absorption spectrum of the polyisocyanate compound having free isocyanate groups by reacting with the blocking agent until the inherent isocyanate group is formed. The absorption spectrum disappears and thus is easily obtained.

Preferred commercially available blocked polyisocyanates include DURANATE MF-K60B (manufactured by Asahi Kasei Chemicals Co., Ltd.) and DESMODUR BL-3475 (manufactured by Sumika Bayer Polyurethane Co., Ltd.) whose blocking agent is an active methylene compound. The blocking agent was TRIXENE BI-7982 (manufactured by Baxenden) of a pyrazole compound, and TRIXENE BI-7992 (manufactured by Baxenden) of a mixed type of active methylene and pyrazole compound.

The main agent and curing agent constituting the thermosetting resin composition can be selected according to the consumption of their functional groups after curing. In simple terms, for example, per 100 parts of the main agent in terms of mass conversion of non-volatile components , the curing agent can be 30 to 800 parts.

In a thermosetting resin composition comprising a combination of a hydroxyl group-containing film-forming thermoplastic resin and an isocyanate curing agent such as blocked polyisocyanate as essential components, in terms of excellent printability, the non-volatility of the isocyanate curing agent is reduced in terms of mass. The non-volatile content of the hydroxyl group-containing film-forming thermoplastic resin is more preferably 5 to 50 parts per 100 parts of components.

(epoxy compound)

As the thermosetting resin composition in the present invention, when a combination of blocked polyisocyanate and hydroxyl group-containing film-forming thermoplastic resin is used, the viscosity can be reduced and the crosslinking density can be increased by using an epoxy compound in combination. , Further improve the adhesiveness and solvent resistance to the substrate of the cured conductive pattern. The epoxy compound used is not particularly limited, but an aliphatic epoxy compound is preferably used. Specifically, epoxides such as polyethylene glycol, polypropylene glycol, hexylene glycol, trimethylolpropane, glycerin, pentaerythritol, sorbitol, and other glycidyl etherified compounds, and alicyclic epoxy compounds are preferably used. Among them, glycidyl etherified products such as polyethylene glycol, polypropylene glycol, and trimethylolpropane are more preferable.

Since the aliphatic epoxy compound is liquid or semi-solid at room temperature, it is possible to reduce the amount of the main ingredient that constitutes the thermosetting resin composition with high viscosity or solid without impairing the conductivity, so that the conductivity can be improved. The fluidity of the ink composition becomes good, and in a specific printing method such as flexographic printing, screen printing, gravure printing, or gravure offset printing, even in the case of continuous printing on these printing machines, it is easy to obtain And stable and good conductive pattern. Partially aromatic epoxy compounds are liquid or semisolid, but are not preferably used from the viewpoint of safety.

When preparing the conductive ink composition of the present invention, when an epoxy compound is used in combination as a constituent of the thermosetting resin composition, the performance of the conductive pattern such as conductivity, toughness, and solvent resistance that is finally obtained can be improved. On the other hand, in terms of mass, it is preferable to use 5 to 50 parts per 100 parts of the total non-volatile components of the thermosetting resin composition contained in the ink composition.

(reaction catalyst for blocked polyisocyanates)

In the blocked polyisocyanate used in the present invention, a reaction catalyst may be used in combination if necessary. The reaction catalyst is not particularly limited, but the reaction catalyst for blocked polyisocyanate is preferably an organic ammonium salt or an organic amidine salt. Specifically, tetraalkylammonium halides, tetraalkylammonium hydroxides, tetraalkylammonium organic acids, etc. as organic ammonium salts, 1,8-diazabicyclo[5.4.0 ]Undecene-7 (below DBU), 1,5-diazabicyclo[4.3.0]nonene-5 (below DBN) phenate, octanoate, oleate, p-toluenesulfonate , formate. Among them, DBU-octanoate and DBN-octanoate are preferably used. Examples of commercially available organic ammonium salts include TOYOCAT-TR20 (manufactured by Tosoh Corporation), and examples of organic amidine salts include U-CAT SA1, U-CAT SA102, U-CAT SA106, U-CAT SA506, U-CAT SA603, U-CATSA1102 (manufactured by San-APRO).

The reaction catalyst of blocked polyisocyanate is preferably 3 to 30 parts per 100 parts of blocked polyisocyanate in terms of mass conversion from the aspect of improving the performance of the conductive pattern such as conductivity and solvent resistance obtained finally.

(Organic solvents)

Since most of the various raw materials used in the present invention are solid at 25° C., it is usually necessary to apply or print a fine line pattern of the conductive ink composition on the substrate after dissolving in a liquid medium or the like. Therefore, when selecting a main ingredient and a curing agent constituting a thermosetting resin composition, it is preferable to consider solubility in a liquid medium.

From such a viewpoint, an organic compound that is liquid at 25° C. is used for the conductive ink composition of the present invention, which is soluble in the thermosetting resin composition and has no reactivity therewith. Such an organic compound is an organic solvent, and its type is not limited, and examples thereof include ester-based, ketone-based, chlorine-based, alcohol-based, ether-based, hydrocarbon-based, ether-ester-based, and the like. Specifically, for example, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, n-butanol, isobutanol, isophorone, γ-butyrolactone, DBE (manufactured by INVISTA Japan) , N-methyl-2-pyrrolidone, ethyl carbitol acetate, butyl cellosol acetate, propylene glycol monoalkyl ether acetate, etc. These may be used alone or in combination of two or more. However, regardless of the type of printing method described later, it is preferable to use a solvent having a boiling point of 100 to 250° C. as the organic solvent in terms of drying speed in order to easily obtain a conductive pattern.

As will be described later, in the case of gravure printing or gravure offset printing, it is preferable to make the silicone cloth swelling rate of such an organic solvent 5 to 20%, particularly preferably diethylene glycol monobutyl ether acetic acid Ether ester organic solvents such as esters, diethylene glycol monoethyl ether acetate, etc.

The content of the organic solvent in the conductive ink composition is preferably 5 to 30% by mass, more preferably 7 to 15% by mass. If it is within this range, the viscosity of the paste will become more appropriate. Especially in gravure printing or gravure offset printing, pinhole defects will not occur at the corners of the drawn lines and the intersections of the matrix, and higher fineness can be formed. Conductive pattern.

The conductive ink composition of the present invention is characterized in that, in addition to the above-mentioned known and commonly used raw material components, it further contains at least A functional organic compound. Phosphate group refers to the group represented by -H ₂ PO ₄ (P atom is valence 5), and phosphate group refers to at least one of the hydrogen atoms in -H ₂ PO ₄ being covered by alkali metal ions, alkaline earth metals A group that is substituted by an ion to form a salt form. In addition, the phosphate group refers to a group in which at least one hydrogen atom in -H ₂ PO ₄ is substituted with an alkyl group or a phenyl group.

Organic compounds containing phosphate groups, organic compounds containing phosphate groups, and organic compounds containing phosphate groups are collectively abbreviated as organic compounds containing phosphate groups.

As such an organic compound containing a phosphoric acid group, for example, polyalkylene glycol monophosphate, polyalkylene glycol monoalkyl ether monophosphate, perfluoroalkyl polyoxyalkylene phosphate, Low-molecular-weight compounds such as perfluoroalkylsulfonamide polyoxyalkylene phosphate, vinylphosphonic acid, acidic phosphoroethyl mono(meth)acrylate, acidic phosphoropropyl mono(meth)acrylate, A phosphoric acid group-containing polymer such as a homopolymer of acidic phosphoryl polyoxyalkylene glycol mono(meth)acrylate or a copolymer of the above-mentioned monomer and other comonomers is used as a polymer compound.

In addition, in the above as a specific example, only the organic compound containing the phosphoric acid group has been exemplified, but the organic compound containing the phosphoric acid salt group can be obtained by combining an alkali metal hydroxide, an alkaline earth metal hydroxide and an organic compound containing a phosphoric acid group. Organic compounds are easy to obtain by reaction. Organic compounds containing phosphate groups can be condensed by dehydration condensation of organic compounds containing phosphate groups and alcohols, and condensed organic compounds containing phosphate groups and alcohols through the action of bases. easily available.

As an organic compound containing a phosphoric acid group, in the comparison of the amount of non-volatile components used in the same amount, from the perspective of being able to have both lower viscosity and lower volume resistivity, compared with an organic compound containing a phosphoric acid ester group, One of an organic compound containing a phosphoric acid group and an organic compound containing a phosphate group is preferable.

As the above-mentioned low-molecular-weight compounds, for example, EFKA series manufactured by Ciba Specialty Chemicals Co., Ltd. can be used. On the other hand, high-molecular compounds can be selected from, for example, DISPERBYK series manufactured by BYK Corporation.

As the above-mentioned polymer compound, a number-average molecular weight of 1,000 or more is preferable, and a polymer containing a phosphoric acid group having a number-average molecular weight of 1,000 to 10,000 is preferable because it is more effective than the above-mentioned low-molecular compound in the same amount of use without impairing conductivity. In this case, the effect of improving the fluidity of the conductive ink composition is high.

The amount of the phosphoric acid group-containing organic compound used in the present invention is preferably 0.1 to 3 parts per 100 parts in terms of mass conversion of the conductive filler, thermosetting resin composition and organic solvent.

In the conductive ink composition of the present invention, in addition to the above-mentioned components, various additives such as dispersants, defoamers, release agents, leveling agents, and plasticizers may be added in appropriate amounts as necessary.

The conductive ink composition of the present invention can be formed by any method, such as coating or printing on any substrate of plastic film, ceramic film, silicon wafer, glass or metal plate to form a corresponding conductive pattern. However, in order to bring out the true value of the conductive ink composition of the present invention, transparent conductive films such as PET films, PP films, or ITO films that cannot be exposed to high temperatures are used when obtaining conductive patterns.

The conductive ink composition of the present invention can be printed on any substrate using a printing method such as flexographic printing, screen printing, gravure printing, or gravure offset printing, and the printed pattern is cured by heating to form a cured film, thereby forming Conductive pattern.

As a method of forming a conductive pattern composed of the conductive ink composition of the present invention, a method of applying the conductive ink composition of the present invention on a non-heat-resistant base material and heating it is exemplified. The conductive ink composition of the present invention can more easily set the viscosity at 25° C. at a shear rate of 10 s ⁻¹ to 1 to 50 Pa·s by containing the above-mentioned organic compound having a phosphoric acid group. As a result, the gravure is filled with a conductive ink composition, the filled ink composition is transferred to a blanket roll, and the ink composition is transferred from the blanket roll to a non-heat-resistant substrate. , so that a desired pattern is printed on the surface of a non-heat-resistant substrate, so-called gravure offset printing is performed, and then a conductive pattern is formed by heating.

As the gravure printing plate at this time, a general gravure plate, a gravure plate formed by exposing, developing, and washing a photosensitive resin on a glass plate, or a plate formed by chemical etching or laser etching on a glass plate, metal plate, or metal roll can be used. intaglio.

In addition, the silicone cloth is a thin plate having a layer structure such as a silicone rubber layer, a PET layer, and a sponge layer, and is usually used in a state wound on a rigid cylinder called a tape roll.

In the method of forming a conductive pattern composed of the conductive ink composition of the present invention, when the above-mentioned gravure offset printing method is used, the transfer from the gravure and the transferability to the substrate are required for the silicone cloth. . In order to obtain sufficient transferability to the base material, it is necessary to absorb the liquid component in the conductive ink composition at a certain ratio on the surface of the adhesive tape. If the absorption is insufficient, the conductive ink composition layer will easily produce interlayer peeling when transferring to the substrate. Conversely, if the absorption exceeds a certain ratio, the conductive ink composition will dry on the surface of the adhesive tape, which will easily cause damage to the substrate. Problems such as poor transfer printing.

By setting the viscosity of the conductive ink composition at 25°C to 1 to 50 Pa·s, when the conductive pattern is continuously printed by the gravure offset printing method, the corners of the drawn lines and the intersections of the matrix Pinhole defects are easy to occur on the surface, good conductive fine line patterns can be formed, and it is difficult to produce inking to the gravure plate, and the transferability from the gravure plate to the adhesive tape is a problem.

The conductive ink composition of the present invention can be applied on a substrate to form a printed pattern such that the line width is in the range of 10 to 150 μm, and cured by heating to form a conductive pattern.

Then, the printed pattern provided on the substrate is heated, for example, at 100 to 130° C. for 20 to 5 minutes to form a cured film and form a conductive pattern to express conductivity.

The conductive pattern formed by the conductive ink composition of the present invention may be a line with a thick line width as β, but the characteristics in the case of using the conductive ink composition of the present invention are as described above. Especially when the thinner line width than before is set on the base material, it is particularly effective.

As described above, since the conductive pattern composed of the conductive ink composition of the present invention can be formed at a lower temperature and in a shorter time than before, the characteristic of the conductive ink composition of the present invention is that it is compatible with ceramic films, glass or metal Compared with a substrate with high heat resistance such as a board, the conductive pattern is particularly exhibited when the conductive pattern is formed on a non-heat-resistant substrate that has lower heat resistance and is easily thermally deformed. Therefore, a conductive pattern in which a cured film of the conductive ink composition of the present invention is formed on a non-heat-resistant substrate can be preferably used as a conductive circuit formed on a non-heat-resistant substrate.

In this way, with regard to the use of the conductive ink composition of the present invention, a substrate provided with a conductive pattern is formed by printing and heating on various substrates using various printing methods, and as a conductive circuit, if necessary, by wiring, etc. , can form various electrical components and electronic components. Specifically, the conductive ink composition of the present invention is also excellent in adhesion to a transparent conductive film such as a transparent ITO electrode.

Examples of final products include lead-out electrodes for touch panels, lead-out electrodes for displays, electronic paper, solar cells, and other wiring products.

Example

The present invention will be specifically described below through examples. Here, "%" means "mass%" unless otherwise specified.

Each raw material was used in the parts by mass described in Table 1, and these raw materials were thoroughly mixed to prepare each conductive ink composition of the present invention as an example and each conventional conductive ink composition as a comparative example.

Regarding each of these conductive ink compositions, the characteristics of the conductive ink composition itself and the characteristics of the conductive pattern obtained therefrom were evaluated by the following measurement items. The evaluation results are also collectively shown in Table 1 and Table 2 below.

(viscosity)

The viscosity of the conductive ink composition of the present invention was measured at 25° C. and a shear rate of 10 s ⁻¹ using a rotational rheometer.

(printing suitability)

Using the conductive ink composition of the present invention, gravure offset printing was performed by the following method to produce a conductive circuit.

After applying the conductive ink composition to a glass intaglio plate using a doctor blade, it is pressed and touched on a cylinder wound with an adhesive tape to transfer a desired pattern onto the adhesive tape. Thereafter, the coating film on the adhesive tape is extruded and transferred onto a transparent conductive film as a base material to fabricate a conductive circuit with a line width of 30 μm to 100 μm. In the conductive circuit described above, lines with a line width of 30 μm were observed microscopically, and thin line reproducibility was evaluated according to the following criteria.

◎: The linearity of the thread is particularly excellent, and there is no broken thread

○: The linearity of the thread is excellent, and there is no broken thread

×: The linearity of the line is poor, and there are broken lines

(volume resistivity)

The conductive ink composition was applied on the transparent conductive film (ITO film surface) using an applicator so that the film thickness after drying was 4 μm, and dried at 125° C. for 10 minutes. Using this ink coating film, it measured by the four-probe method using LORESTA GP MCP-T610 (made by Mitsubishi Chemical Corporation). Volume resistivity is the standard of high or low conductivity.

[Table 1]

[Table 2]

Silver powder:

AG-2-1C (manufactured by DOWA Electronics Co., Ltd., average particle size D50: 0.8 μm)

BYRON 200: Molecular weight 17,000, hydroxyl value 6, glass transition temperature (Tg) 67°C, thermoplastic polyester resin (manufactured by Toyobo Co., Ltd.)

SOLBIN AL: A vinyl chloride-vinyl acetate copolymer with a number average molecular weight of 22,000, a glass transition temperature (Tg) of 76°C, and a copolymerization mass ratio of vinyl chloride/vinyl acetate/vinyl alcohol of 93/2/5 (Nissin Chemical Co., Ltd. industrial company)

DENACOL EX-321: Trimethylolpropane polyglycidyl ether (manufactured by Nagasechemtex Co., Ltd.)

TRIXENE BI7982: Blocked isocyanate whose blocking agent is 3,5-dimethylpyrazole (manufactured by Baxenden)

DISPER BYK-111: Phosphate group-containing polymer (polymer compound) with a number average molecular weight in the range of 1,000 to 10,000 (manufactured by BYK Corporation)

EFKA-8512: Phosphate ester (low molecular weight compound) containing polyoxyalkylene group (manufactured by Ciba Specialty Chemicals Co., Ltd.)

U-CAT SA 102: DBU-octanoate (manufactured by San-APRO)

U-CAT SA 603: DBU-formate (manufactured by San-APRO)

CUREZOL 2E4MZ: 2-Ethyl-4-methylimidazole (manufactured by Shikoku Chemicals Co., Ltd.)

EDGAc: Diethylene glycol monoethyl ether acetate

As can be seen from the evaluation results in Table 1, the conductive ink composition of Example 4 containing an organic compound having a phosphate group, compared with the conductive ink composition of Comparative Example 1 that does not contain it, has lower viscosity and printing adaptability. All excellent. As can be seen from the comparison of Examples 3 and 4, when a polymer compound is used as the phosphoric acid group-containing organic compound, the viscosity and conductivity are significantly better than the case of using a phosphoric acid ester group-containing low-molecular compound.

It can be seen that, with regard to the conductive ink compositions of Examples 3 to 4, the ratio of the non-volatile components of the hydroxyl-containing film-forming thermoplastic resin and the isocyanate curing agent is such that the latter has more curing agent and is lower than the former thermoplastic resin. Compared with the conductive ink composition of many Examples 1-2, printing suitability was more excellent.

In addition, since the conductive ink compositions of the examples all block the isocyanate, the blocking agent is a low-temperature dissociated active methylene compound and/or pyrazole compound, so even in non-resistant films such as transparent conductive films and PET films A conductive pattern made of a cured film can also be formed on a thermal substrate at a low temperature and in a short time without warping, and the obtained conductive pattern is also sufficiently satisfactory in terms of conductivity and substrate adhesion.

industry availability

The conductive ink composition of the present invention can be used as a conductive silver paste for forming conductive patterns of various electric components and electronic components.

Claims (8)

1. A conductive ink composition, it is characterized in that, described conductive ink composition contains conductive filler, thermosetting resin composition, organic solvent as essential component, further contains from phosphoric acid group, phosphate group , an organic compound with at least one functional group selected from the group consisting of phosphate groups, the thermosetting resin composition is a thermosetting resin composition containing a film-forming thermoplastic resin having a hydroxyl group and a blocked polyisocyanate, and the blocked polyisocyanate Blocking agents for isocyanates are active methylene compounds or pyrazole compounds. 2. The conductive ink composition according to claim 1, wherein the organic compound contains at least one functional group selected from the group consisting of a phosphoric acid group, a phosphate group, and a phosphoric acid ester group, and several A polymer with an average molecular weight of 1,000 or more. 3. The conductive ink composition according to claim 1, wherein the conductive filler is spherical silver powder with an average particle diameter of 0.1-3 μm. 4. The conductive ink composition according to claim 1, further using an epoxy compound in combination. 5 . The conductive ink composition according to claim 1 , which has a viscosity of 1 to 50 Pa·s at 25° C. and a shear rate of 10 s ⁻¹ . 6. A method for producing a conductive pattern, comprising applying the conductive ink composition according to any one of claims 1 to 4 on a non-heat-resistant base material, followed by heating. 7. The manufacturing method of the conductive pattern according to claim 6, filling the conductive ink composition according to any one of claims 1 to 4 in the gravure, and transferring the filled conductive ink composition to After printing on the blanket roll, the conductive ink composition is transferred from the blanket roll to a non-conductive support to print a desired pattern on the surface of the non-heat-resistant substrate, followed by heating. 8 . A conductive circuit comprising a conductive pattern in which a cured film of the conductive ink composition according to claim 1 is formed on a non-heat-resistant substrate.