JP5569732B2 - Conductive silver paste, conductive pattern forming method, and printed conductive pattern - Google Patents

Description

  The present invention relates to a conductive silver paste for forming a conductive film, a conductive pattern printing method, and a printed conductive pattern.

Printing methods or etching methods are known as methods for forming conductive patterns such as conductive circuits and electrodes used in touch panels, electronic paper, and various electronic components.
When forming a conductive pattern by an etching method, after forming a resist film patterned by photolithography on a substrate on which various metal films are vapor-deposited, an unnecessary vapor-deposited metal film is dissolved and removed chemically or electrochemically, Finally, it is necessary to remove the resist film, and the process is very complicated and poor in mass productivity.
On the other hand, in the printing method, a desired pattern can be mass-produced at low cost, 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, ink jet printing, and the like have been proposed in accordance with the line width, thickness, and production speed of the pattern to be formed.

As a printed pattern, formation of a high-definition conductive pattern having a line width of 50 μm or less is required from the viewpoint of miniaturization of an electronic device and improvement in design.
In addition, in order to respond to the increasing demand for thinner, lighter, more flexible electronic devices, and high-productivity roll-to-roll printing, high conductivity is achieved by printing on plastic films and firing at low temperature and short time. There is a need for conductive inks that can provide good properties, substrate adhesion, film hardness, and the like. Furthermore, among plastic films, there is a need for a conductive ink that can provide the above-mentioned physical properties when printed on an inexpensive and highly transparent PET film or a transparent conductive film in which an ITO film is formed on the PET film. Yes.

In Patent Documents 1 and 2, when the baking temperature is 150 ° C. and the printing substrate is a PET film, there is a problem that the substrate is deformed.
In Patent Document 3, although the firing temperature is 120 ° C. and a relatively low temperature, the firing time is as long as 30 minutes and the productivity is poor. Moreover, the adhesiveness of the transparent conductive film to the ITO film has not been studied.
In patent document 4, although high electroconductivity is obtained by baking at low temperature for a short time, since the organic solvent with high drying property is used, it is inferior to on-machine stability. Also, the printed line width is as thick as 3 mm, and high-definition patterning has not been studied.

JP 2009-62523 A JP 2005-56778 A JP 2006-302825 A WO2006 / 095611 JP 2007-119682 A

  As described above, in the prior art, a conductive silver paste that can obtain a conductive pattern excellent in adhesion to a substrate in a short time of 10 minutes or less even at a low temperature of less than 150 ° C. has not been obtained yet. It was the actual situation.

  Therefore, as a result of intensive studies, the present inventors have solved the above-mentioned drawbacks by using specific silver particles and a vinyl chloride-vinyl acetate copolymer having a specific composition in combination. As a result, the present invention has been completed.

That is, the present invention relates to a silver particle (A) having a median diameter (D50) of 0.2 to 0.9 μm, a vinyl chloride-vinyl acetate copolymer, and vinyl alcohol and / or (meth) acrylic in the copolymer. A vinyl chloride-vinyl acetate copolymer (B) containing 3 to 9% by weight of a polymer unit of acid hydroxyalkyl ester, and the copolymer (B) is dissolved to have reactivity with the copolymer (B). A conductive silver paste containing an organic compound (C) that is liquid at 25 ° C. as an essential component is provided.
Moreover, this invention provides the formation method of the electroconductive pattern which carries out gravure printing or gravure offset printing on the base material with the above-mentioned electroconductive silver paste.
Furthermore, this invention provides the electroconductive pattern printed matter formed with the electroconductive silver paste of the said description.

The conductive silver paste of the present invention uses a vinyl chloride-vinyl acetate copolymer having specific silver particles and a specific composition, so that a conductive pattern having excellent adhesion to a substrate can be obtained at low temperature for a short time. It has a particularly remarkable effect that it can be obtained with
The conductive pattern forming method of the present invention uses a vinyl chloride-vinyl acetate copolymer having specific silver particles and a specific composition, so that the conductive pattern excellent in adhesion to the substrate and its There is an especially remarkable effect that the printed matter can be obtained at low temperature in a short time.

  The conductive silver paste of the present invention comprises a silver particle (A) having a median diameter (D50) of 0.2 to 0.9 μm, a vinyl chloride-vinyl acetate copolymer, vinyl alcohol and / or in the copolymer. A vinyl chloride-vinyl acetate copolymer (B) containing 3 to 9% by weight of a polymerization unit of hydroxyalkyl ester (meth) acrylate, and the copolymer (B) by dissolving the copolymer (B) It is a conductive silver paste containing, as an essential component, an organic compound (C) that is not reactive and is liquid at 25 ° C.

As the silver particles (A) used in the conductive silver paste of the present invention, spherical silver powder having a median particle diameter (D50) of 0.2 to 0.9 μm can be used.
As such silver particles (A), for example, 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), Sylbest C-34 (Tokuriku Chemical Laboratory Co., Ltd., average particle size D50: 0.35 μm) and the like. It is done.

  Silver particles (A) having a median diameter (D50) of 0.2 to 0.9 μm can be used alone, but when used in combination with silver particles having a median diameter (D50) of 1.0 to 10.0 μm, high definition It is preferable because it is possible to combine the formation of a thin conductive pattern with sufficient conductivity by firing at less than 150 ° C.

  Examples of such silver particles having a median diameter (D50) of 1.0 to 10.0 μm include AG2-1 (manufactured by DOWA Electronics Co., Ltd., average particle diameter D50: 1.3 μm), Sylbest AgS-050 (( For example, manufactured by Tokuru Chemical Laboratory Co., Ltd., average particle diameter D50: 1.4 μm).

  By using together 50 to 200 parts of silver particles (A) per 100 parts of silver particles having a median diameter (D50) of 1.0 to 10.0 μm in terms of mass, the flowability of the conductive silver paste is further improved. In a specific printing method such as flexographic printing, screen printing, gravure printing, or gravure offset printing, even when continuously printing on these printing machines, trouble is unlikely to occur and the conductive pattern is stably stable. Since it becomes easy to obtain printed matter, it is especially preferable.

  In the conductive silver paste of the present invention, silver particles are used as an essential component. However, if necessary, other single metal or alloy particles may be used in combination.

  In recent years, as a base material for forming a conductive pattern, use of a plastic film material having high flexibility (flexible) has been demanded so that electronic parts can be filled in a narrow casing with high density. Under such a demand, high adhesion is required so that the conductive pattern does not peel from the substrate even if it is held for a long time in a warped state. When the base material forming the conductive pattern of the conductive silver paste is, for example, polyethylene terephthalate (hereinafter referred to as PET), a vinyl chloride-vinyl acetate copolymer is used as the resin that is solid at 25 ° C. Has been.

  Therefore, in the present invention, as the vinyl chloride-vinyl acetate copolymer, a vinyl chloride-vinyl acetate copolymer (B) containing 3 to 9% by weight of polymer units of vinyl alcohol and / or hydroxyalkyl ester (meth) acrylate. Was selectively used. Vinyl chloride-vinyl acetate copolymers of various chemical compositions have been used in the preparation of conductive silver pastes, but the inventors differed significantly in adhesion to the substrate depending on their composition. It has been found that only the specific vinyl chloride-vinyl acetate copolymer described above is remarkably excellent in adhesion to the substrate. As a result, the dispersibility of the silver particles can be promoted as compared with the case where the hydrophilic group such as a hydroxyl group is not present, and it is possible to improve the adhesion particularly to the PET.

  In the vinyl chloride-vinyl acetate copolymer (B) used in the present invention, the vinyl chloride-vinyl acetate copolymer containing a vinyl alcohol polymer unit in the copolymer is, for example, a vinyl chloride-vinyl acetate copolymer. Can be easily obtained by partial saponification to contain a necessary amount of vinyl alcohol polymerized units, and a vinyl chloride-vinyl acetate copolymer containing polymerized units of hydroxyalkyl ester (meth) acrylate in the copolymer. In addition to vinyl chloride and vinyl acetate, the polymer is copolymerized using a required amount of hydroxyalkyl (meth) acrylate such as hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate as a comonomer. Can be easily obtained.

  As the vinyl chloride-vinyl acetate copolymer, Nisshin Chemical Industry Co., Ltd., Union Carbide Co., and Wacker Polymer Co., Ltd. are known, and straight (unmodified) vinyl chloride-vinyl acetate copolymer. And vinyl chloride-vinyl acetate copolymer containing polymer units of vinyl alcohol and / or hydroxyalkyl ester (meth) acrylate. Examples of the vinyl chloride-vinyl acetate copolymer (B) containing 3 to 9% by weight of polymer units of vinyl alcohol and / or hydroxyalkyl ester (meth) acrylate include Solvain AL, Solvain TAO (above, Nissin) Chemical Industry Co., Ltd.), VAGD, VAGH (manufactured by Union Carbide), LL4310 (manufactured by Wacker Polymer).

  The vinyl chloride-vinyl acetate copolymer (B) is capable of forming a tack-free resin film by itself, but is itself solid at 25 ° C., and thus usually dissolved in a liquid medium. Above, it is necessary to apply or print a fine line pattern on the substrate. Therefore, in selecting the copolymer (B), it is necessary to consider the solubility in the liquid medium.

  From such a viewpoint, in the conductive silver paste of the present invention, the organic compound (C), which is liquid at 25 ° C., dissolves the copolymer (B) and has no reactivity with the copolymer (B). , Used in combination with this copolymer (B).

  Such an organic compound (C) is a so-called organic solvent, and the type thereof is not limited, and examples thereof include ester, ketone, chlorine, alcohol, ether, hydrocarbon, and ether ester. Specifically, for example, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, n-butanol, iso-butanol, isophorone, γ-butyrolactone, DBE (manufactured by Invista Japan), N-methyl-2-pyrrolidone, ethyl carbitol acetate, butyl cellosolve Examples thereof include acetate and propylene glycol monoalkyl ether acetate. These may be used individually by 1 type, or may use 2 or more types together. Among these, in order to easily obtain a conductive pattern regardless of the type of printing method to be described later, it is preferable from the viewpoint of drying speed that the organic compound (C) has a boiling point of 100 to 250 ° C. .

  As will be described later, when the gravure printing method or the gravure offset printing method is employed, the organic compound (C) preferably has a silicone blanket swelling ratio of 5 to 20%, particularly preferably diethylene glycol. Ether ester organic solvents such as monobutyl ether acetate and diethylene glycol monoethyl ether acetate.

  The conductive silver paste of the present invention is a reaction between the silver particles (A), the vinyl chloride-vinyl acetate copolymer (B), and the copolymer (B) by dissolving the copolymer (B). However, if necessary, in addition to the vinyl chloride-vinyl acetate copolymer (B), other components may be used. A resin that is solid at 25 ° C. and can form a tack-free resin film alone can be used in combination. Examples of such other resins include polyester resins, vinyl chloride resins, acrylic resins, polyester resins, polyurethane resins, and the like. These may be used alone or in combination of two or more.

  The conductive silver paste of the present invention is a reaction between the silver particles (A), the vinyl chloride-vinyl acetate copolymer (B), and the copolymer (B) by dissolving the copolymer (B). It can be prepared by mixing a liquid organic compound (C) as an essential component at 25 ° C., which has no properties. The conductive silver paste can be produced by kneading and homogenizing the above raw materials as essential components.

  In preparing the conductive silver paste of the present invention, in terms of mass, the vinyl chloride-vinyl acetate copolymer (B) is 1 to 10 parts as a nonvolatile component per 100 parts of silver particles, and the copolymer (B). It is possible to use 20 to 35 parts of the organic compound (C) that is liquid at 25 ° C., which has no reactivity with the copolymer (B), and the performance of the conductive pattern finally obtained It is preferable from the point which can raise a conductive pattern formation condition and the point which can be improved.

  The content of silver particles in the conductive silver paste is preferably 60 to 95% by mass, and more preferably 70 to 90% by mass. Within this range, the density of the silver particles in the film is sufficient, good electrical conductivity can be obtained, and it becomes easy to prepare a fluid paste.

  The content of the vinyl chloride-vinyl acetate copolymer (B) in the conductive silver paste is preferably 1 to 10% by mass, and more preferably 2 to 7% by mass. This range is preferable in that the adhesion to the substrate on which the conductive pattern is provided can be further increased.

  The content in the conductive silver paste of the organic compound (C), which is liquid at 25 ° C. and dissolves the copolymer (B) and has no reactivity with the copolymer (B), is 10 to 40% by mass. Is preferably 15 to 25% by mass. In this range, the paste viscosity becomes more appropriate, and in gravure printing or gravure offset printing, a higher-definition conductive pattern can be formed without causing pinhole defects at the corners of the image lines or at the intersections of the matrix. Can be formed.

  In the conductive silver paste of the present invention, various additives such as a curing agent, a dispersant, an antifoaming agent, and a plasticizer can be appropriately blended as needed in addition to the above-described components.

  In the conductive silver paste of the present invention, a vinyl chloride-vinyl acetate copolymer containing a hydroxyl group based on a polymerization unit of vinyl alcohol and / or hydroxyalkyl ester (meth) acrylate as described above is used. Therefore, by using together a curing agent containing a functional group capable of reacting with the hydroxyl group of the copolymer (B), both can be cross-linked, and the solvent resistance of the resulting conductive pattern is further improved. be able to.

  Examples of such curing agents include amino resins such as methylated melamine resins, butylated melamine resins, benzoguanamine resins, and urea resins, acid anhydrides, imidazoles, epoxy resins, phenol resins, and polyisocyanate compounds. . These may be used alone or in combination of two or more.

  However, at room temperature, using a curing agent containing a functional group capable of reacting with a hydroxyl group of the vinyl chloride-vinyl acetate copolymer (B) containing a hydroxyl group, the curing reaction gradually proceeds over time, Since the paste thickens, it becomes difficult to stably apply and print on the base material. Therefore, once the conductive silver paste is prepared, it is necessary to apply and print the base material as soon as possible. On the other hand, when a curing agent that does not proceed unless the reaction with the hydroxyl group of the vinyl chloride-vinyl acetate copolymer (B) is performed at a high temperature, warping may occur depending on the type, shape, or size of the substrate used. Inconvenience that a large amount of energy is consumed when heating for curing occurs.

  From such a viewpoint, for example, when a conductive pattern is formed on a plastic film as a base material, for example, at 50 to 140 ° C. with the hydroxyl group of the vinyl chloride-vinyl acetate copolymer (B) It is preferable to use a curing agent that initiates the reaction. As such a curing agent, a blocked polyisocyanate compound (D) in which the blocking agent is thermally dissociated to generate a free isocyanate group is preferable because it is easier to handle.

  In particular, when a PET film is used as a plastic film as a plastic film, the block polyisocyanate compound (D) using a blocking agent such that the temperature at which an isocyanate group is generated is 70 to 125 ° C. is used as a conductive silver. If it is made to contain in a paste, a conductive pattern can be formed on it, without generating curvature etc. to a PET film.

  Preparation of the conductive silver paste of the present invention is slightly different depending on the amount of hydroxyl group in the vinyl chloride-vinyl acetate copolymer (B) used and the combination of the blocking agent and the polyisocyanate compound constituting the blocked polyisocyanate compound (D). Therefore, the block polyisocyanate compound (D) is finally obtained by using 20 to 30 parts in terms of mass per 100 parts of the nonvolatile content of the vinyl chloride-vinyl acetate copolymer (B). From the viewpoint of improving the performance of the conductive pattern such as conductivity, toughness, and solvent resistance.

  The block polyisocyanate compound (D) used in the present invention, in which the blocking agent is thermally dissociated to generate a free isocyanate group, is composed of a blocking agent and a polyisocyanate compound.

  The diisocyanate used as a raw material for the polyisocyanate compound is not particularly limited, and examples thereof include aromatic, aliphatic, and alicyclic diisocyanates. It may be used alone or in combination. Examples of the aromatic diisocyanate include 2,4-toluene diisocyanate, 2,6-triene diisocyanate, diphenylmethane-4,4′-diisocyanate, diphenylmethane-2,4′-diisocyanate, and dianisidine diisocyanate. Examples of the aliphatic diisocyanate include 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate (hereinafter referred to as HMDI), 2,2,4-trimethyl-1,6-hexamethylene. And diisocyanate. Examples of the alicyclic diisocyanate include lysine diisocyanate, isophorone diisocyanate (hereinafter referred to as IPDI), 1,3-bis (isocyanatemethyl) -cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, and the like.

  On the other hand, examples of blocking agents include phenolic, active methylene, mercaptan, acid amide, acid imide, imidazole, urea, oxime, amine, imide, and bisulfite compounds. You may use individually or in mixture. Specifically, phenols such as phenol, cresol, ethylphenol, butylphenol, nonylphenol, dinonylphenol, styrenated phenol, oxybenzoate, dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, etc. Active methylenes, mercaptans such as butyl mercaptan, dodecyl mercaptan, acetanilide, acetic acid amide, ε-caprolactam, δ-valerolactam, γ-butyrolactam and other acid amides, succinimide, maleic acid imide and other acid imides Imidazole such as imidazole and 2-methylimidazole, urea such as urea, thiourea and ethyleneurea, formal oxime, acetal oxime, acetoxime, methyl ethyl ketoxy There are oximes such as cyclohexanone oxime, amines such as diphenylamine, aniline and carbazole, imines such as ethyleneimine and polyethyleneimine, and bisulfites such as sodium bisulfite, but stability and dissociation as blocking agents. From the viewpoint of excellent balance, styrenated phenol, oxybenzoic acid ester, acetooxime, methyl ethyl ketoxime, and ε-caprolactam are preferable.

  Such a blocked polyisocyanate compound (D) in which the blocking agent is thermally dissociated to generate a free isocyanate group is converted into an isocyanate group while monitoring the infrared absorption spectrum of the polyisocyanate compound having a free isocyanate group. It can be easily obtained by reacting the blocking agent until the intrinsic absorption spectrum based thereon disappears.

  The conductive silver paste of the present invention is preferably prepared so as to have a viscosity applicable to various printing methods regardless of whether the block polyisocyanate compound (D) is contained or not. ˜30 Pa · S is preferable in order to enable application to a printing method such as gravure printing or gravure offset printing. The viscosity of the conductive silver paste in the present invention is a value measured with a rheometer.

  The conductive silver paste of the present invention can form a conductive pattern by any method, for example, by applying or printing on a plastic film, ceramic film, glass or metal plate substrate. .

  The conductive silver paste of the present invention can form a conductive pattern on an arbitrary substrate by, for example, printing by flexographic printing, screen printing, gravure printing, or gravure offset printing.

  The method of forming a conductive pattern from the conductive silver paste of the present invention includes at least a step of supplying a conductive ink to an intaglio printing plate having a conductive pattern, pressing a silicone blanket, and placing the conductive ink on the blanket. A gravure offset printing method having a step of transferring to a substrate and a step of transferring the conductive ink on the blanket to a substrate can be suitably employed.

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

  The silicone blanket is a sheet having a layer structure such as a silicone rubber layer, a PET layer, or a sponge layer. Usually, it can be used in a state of being wound around a rigid cylinder called a blanket cylinder.

  In the method for forming a conductive pattern from the conductive silver paste of the present invention, when the gravure offset printing method is employed, the silicone blanket is required to have transferability from the intaglio and transferability to the substrate. In order to obtain sufficient transferability to the substrate, it is necessary to absorb the liquid component in the conductive silver paste at a certain rate on the blanket surface. If the absorption is insufficient, the conductive silver paste layer is likely to delaminate at the time of transfer to the substrate, and conversely if absorbed above a certain percentage, the conductive silver paste dries on the blanket surface, There was a problem that transfer defects were likely to occur.

  By setting the viscosity of the conductive silver paste at 25 ° C. to 3 to 30 Pa · s, when the conductive pattern is continuously printed using the gravure offset printing method, Pinhole defects are likely to occur at the intersections of the matrix, a good conductive fine line pattern can be formed, and problems of inking to the intaglio and transfer from the intaglio to the blanket are less likely to occur.

  The conductive pattern formed from the conductive silver paste of the present invention may be a solid line having a solid line width, but the characteristics when the conductive silver paste of the present invention is used are as described above. This is particularly noticeable when a narrower line width than conventional ones is provided on a substrate.

  In addition, since the conductive pattern from the conductive silver paste of the present invention can be formed at a lower temperature and in a shorter time than conventional, the conductive silver paste of the present invention is characterized by heat resistance such as ceramic film, glass or metal plate. When the conductive pattern is formed on a general-purpose plastic film such as PET, which has a lower heat resistance and is more easily thermally deformed than a substrate having a high thickness, it is particularly prominent.

  Thus, using the conductive silver paste of the present invention, the base material provided with the conductive pattern by printing on various base materials by various printing methods can be used as a printed conductive pattern, with wiring or the like as necessary. By carrying out, it can be set as various electrical components and electronic components. Specifically, the conductive silver paste of the present invention is excellent in adhesion to a transparent conductive film such as a transparent ITO electrode.

  Examples of the final product include a touch panel extraction electrode, a display extraction electrode, electronic paper, a solar battery, and other wiring products.

  Hereinafter, the present invention will be specifically described with reference to examples. Here, “%” is “% by mass” unless otherwise specified.

A silver particle, a vinyl chloride-vinyl acetate copolymer, an organic compound (C) which is liquid at 25 ° C. at 25 ° C., in which the copolymer (B) is dissolved and has no reactivity with the copolymer (B); The block polyisocyanate compound (D) in which the agent is thermally dissociated by heat dissociation so as to have the mass parts listed in Table 1 below, and these raw materials are sufficiently mixed together, and this is an example. Each conductive silver paste of the invention and each conventional conductive silver paste as a comparative example were prepared. Each of the conductive silver pastes of Examples and Comparative Examples was in the range of a viscosity of 3 to 30 Pa · S at 25 ° C.
About each of these electroconductive silver paste, the characteristic of electroconductive silver paste itself and the electroconductive pattern obtained from it were evaluated in the following measurement items. The evaluation results are also summarized in Table 1 below.

(Specific resistance)
Specific resistance means volume resistivity. Using an applicator, the conductive silver paste was applied onto the transparent conductive film (ITO film surface) so that the film thickness after drying was 6 μm and dried at 120 ° C. for 10 minutes. Using the dried coating film, measurement was performed by a four-terminal method using Loresta GP MCP-T610 (manufactured by Mitsubishi Chemical Corporation). The smaller this value, the better the conductivity.

(Base material adhesion)
A test was carried out in accordance with the procedure of ISO 2409 (Paints and varnishes-Cross-cut test) using a dry coating film prepared from the paste, which was produced in the same manner as the evaluation of the specific resistance, and was evaluated according to the following criteria.
Pass: Class 0 or Class 1 (coating peeling is within 5%)
Fail: Classification 2-5 (peeling film exceeds 5%)

(Solvent resistance)
The ink coating film produced in the same manner as the evaluation of the specific resistance was rubbed 30 times with a cotton swab impregnated with methyl ethyl ketone, and the state of the ink coating film was observed and evaluated according to the following criteria.
Pass: No peeling of paint film Fail: There is peeling of paint film

In Table 1, the details of each raw material used for the preparation of the conductive silver paste are as follows.
・ Silvesto AGS-050:
Silver particle dry powder with a median diameter (D50) of 1.4 μm (manufactured by Tokuri Chemical Laboratory Co., Ltd.)
・ Sylvest C-34:
Silver particle dry powder having a median diameter (D50) of 0.35 μm (manufactured by Tokuru Chemical Laboratory Co., Ltd.)
・ Solvine AL:
Vinyl chloride-vinyl acetate copolymer with a vinyl chloride / vinyl acetate / vinyl alcohol copolymer mass ratio of 93/2/5 (manufactured by Nissin Chemical Industry Co., Ltd.)
・ Solvine TAO:
Vinyl chloride / vinyl acetate copolymer having a vinyl chloride / vinyl acetate / vinyl alcohol copolymer mass ratio of 91/2/7 (manufactured by Nissin Chemical Industry Co., Ltd.)
・ Solvine C:
Vinyl chloride-vinyl acetate copolymer having a vinyl chloride / vinyl acetate copolymer mass ratio of 87/13 (manufactured by Nissin Chemical Industry Co., Ltd.)
・ Solvine TA5R:
Vinyl chloride / vinyl acetate copolymer having a vinyl chloride / vinyl acetate / vinyl alcohol copolymer mass ratio of 88/1/11 (manufactured by Nissin Chemical Industry Co., Ltd.)
Death module BL-3475:
Block diisocyanate (manufactured by Sumika Bayer Urethane Co., Ltd.) masked with a blocking agent that thermally dissociates at 70 to 120 ° C, based on HMDI and IPDI
・ BDGAc:
Diethylene glycol monobutyl ether acetate

As can be seen from the evaluation results in Table 1, the conductive silver pastes of Examples 1 and 2 using a vinyl chloride-vinyl acetate copolymer containing 3 to 9% by weight of vinyl alcohol polymerized units have a specific resistance and a base material. The conductive silver pastes of Comparative Examples 1 and 2 using a vinyl chloride-vinyl acetate copolymer that does not contain vinyl alcohol polymerized units or contains 11% by weight, whereas the adhesion is satisfactory. It is clear that the substrate adhesion is at an unsatisfactory level.
Further, from the comparison between Example 1 and Example 3, those using a blocked polyisocyanate compound in which the blocking agent is thermally dissociated to generate a free isocyanate group are more resistant to solvent as compared to the case without it. It is clear that it is excellent.

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

Claims (6)

A median diameter (D50) 0.2~0.9μm silver particles (A), vinyl chloride - containing 3-9% by weight of polymerized units of vinyl alcohol in a vinyl acetate copolymer copolymer Essentially a vinyl chloride-vinyl acetate copolymer (B) and an organic compound (C) that is liquid at 25 ° C. and dissolves the copolymer (B) and has no reactivity with the copolymer (B). conductive silver paste you containing as components.   The conductive silver paste according to claim 1, wherein the organic compound (C) which is liquid at 25 ° C and dissolves the copolymer (B) is an ether ester organic solvent. Blocking agent comprises further blocked polyisocyanate compound capable of generating free isocyanate groups to thermally dissociate the (D), according to claim 1 or according to 2 conductive silver paste.   The conductive silver paste according to any one of claims 1 to 3, which has a viscosity of 3 to 30 Pa · S at 25 ° C.   The formation method of the electroconductive pattern which carries out gravure printing or gravure offset printing on the base material with the electroconductive silver paste as described in any one of Claims 1-4.   The electroconductive pattern printed matter formed with the electroconductive silver paste as described in any one of Claims 1-4.