JPH05311103A - Printing ink for silver conductor circuit and method for forming silver conductor circuit - Google Patents

Abstract

PURPOSE:To obtain the product containing a specific resin component, a silver component and a flux component, high in accuracy of position after backing high in resolving power of line/space and capable of forming a fine pattern having good leveling property on a substrate. CONSTITUTION:The product contains (A) a resin component selected from a (modified) alkyd resin, a fatty acid epoxy resin, an urethanated oil, rosin and maleated oil, (B) a silver component (preferably metallic silver powder singly dispersed and having 0.1-0.5mum particle diameter) and (C) a flux component. As the component C, e.g. a PbO-B2O3-SiO2 based glass frit having 350-600 deg.C softening point is used when a glass substrate is used as a substrate for printing a pattern or SiO2-Al2O3-CaO based glass frit having high softening point is used when an alumina substrate is used as the substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing ink and a forming method for forming a silver conductor circuit on various substrates used as electronic industrial materials.

[0002]

2. Description of the Related Art Conventionally, a screen printing method using a silver paste has been widely used for forming a silver conductor circuit on a substrate. Although this method is inexpensive and can produce a large amount of printed patterns, it has a drawback that it is difficult to form a fine pattern having a line / space of 50 μm. Further, in screen printing, since a screen mesh is used for the printing plate, there is a drawback that the positional accuracy is deteriorated because of positional deviation when printing on a large base material.

On the other hand, a photolithography method is used as a method for forming a fine pattern. Although this method can form a fine pattern, it requires a large amount of equipment for manufacturing, has complicated processes, and requires labor, resulting in high production cost and low cost of supplying products. .. Further, when a film is formed by using only metallic silver powder for the resin, there is no leveling property and the ink does not spread to the details, so the surface becomes rough.
There was also a drawback that the base was so rough that it was transparent. As a result, there are also problems such as abnormal discharge from the conductor portion and an increase in resistance value.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the conventional method, and dissolves a resin component, a solvent component, an additive component, a silver component and a flux component,
PROBLEM TO BE SOLVED: To provide a method for offset printing of a pattern on a substrate using a kneaded offset printing ink for a silver conductor circuit to form a fine pattern with high positional accuracy after firing, high line / space resolution and good leveling property. With the goal.

[0005]

The method of the present invention comprises at least one resin component selected from alkyd resin, modified alkyd resin, fatty acid epoxy resin, urethanized oil, rosin and maleated oil, a solvent component and an additive component. A step of offset-printing a pattern on a substrate using an offset printing ink for a silver conductor circuit in which a silver component and a flux component are dissolved and kneaded, and the printing pattern is left as it is or / or by irradiation with active energy rays and / or heating. A method of forming a silver conductor circuit comprising a step of curing, a step of overprinting the cured print pattern as it is or the same pattern, and a step of firing the print pattern.

As the resin of the present invention, it is necessary to select a resin that suits the printability of offset printing, and alkyd resin, modified alkyd resin, fatty acid modified epoxy resin, urethanized oil, rosin and maleated oil, etc. are preferable, and they may be used alone or as a mixture. Use the one that you made. Although the amount of resin varies depending on the content of silver, it is preferably 3 to 40% in consideration of printability.

The solvent used in the present invention is not particularly limited, but it has the purpose of dissolving a solid resin and additives in a liquid state and the role of a thickener for lowering the viscosity. Xylene, toluene, butanol, mineral spirits, petroleum solvents (solveso, naphtha), methyl isobutyl ketone, pine oil, terpinol, etc. are used to dissolve solid resins. No. 6 solvent is used.

The metallic silver powder is spherical with a particle size of 0.05 to 1.0 μm,
It is preferably monodispersed with a particle size of 0.1 to 0.5 μm. The flake powder is 0.1-10 μm, more preferably
0.5 to 5 μm is preferable, and spherical ones may be used alone or flakes may be mixed in a silver ratio of 10% to 75%, preferably 20% to 50%. The silver powder used at this time has a purity of 95-99.9%. The particle size of the spherical silver powder was set to 0.05 to 1.0 μm because if the particle size is less than 0.05 μm, the particle size is too small and the printability is unsatisfactory due to lack of elasticity, and the particle size is less than submicron. This is because the difficulty of

On the other hand, when the thickness exceeds 1.0 μm, there is a problem that ink cannot be uniformly deposited on the roller during inking and stable printing cannot be performed. The reason why the flake powder is mixed with the spherical powder is that when the flakes are located on the line, there is a large contact between the powders and the resistance of the conductor is reduced.

The silver-containing organometallic compound of the present invention is preferably a carboxylate, an acetylacetate or a metal alkoxide. The carboxylic acid salt may be 2-ethylhexanoic acid, octylic acid, neodecanoic acid, naphthenic acid or the like, and is not particularly limited as long as it is a carboxylic acid. The alcohol used for the metal alkoxide may be one having 1 to 12 carbon atoms.

The silver-containing colloid of the present invention may have a colloidal particle size of 100 to 1000Å, and a colloidal solution existing in an organic solvent may be used for the ink. By adding the above-mentioned silver-containing organometallic compound or colloid other than the metallic silver powder, the silver component is sufficiently spread to the details, and the undercoat is not transparent. As a result, fine pattern disconnection can be prevented and the resistance value can be reduced. Further, since the smoothness is improved, the surface roughness of the film is also reduced.

The additive components of the present invention are a leveling agent, a polymerization initiator, an oxidation promoter, an anti-skinning agent, a thickener, a metal chelate resin, a dispersant and a filler, which are added depending on the suitability of the ink. For example, if it is a leveling agent, it is advisable to add 0.1 to several% of a silicon compound. Acrylic oligomer as polymerization initiator, cobalt naphthenate and manganese naphthenate as oxidation promoter, methyl ethyl ketone oxime as anti-skinning agent, thickening varnish as thickener, linseed oil fatty acid salt, stearate, oleic acid as metal chelate resin. There is salt etc.

The filler is Al ₂ O ₃ , TiO ₂ , BiO
₂ , fine powder such as SnO ₂ may be used, and from 0.05 μm
A powder of 10 μm or less may be used. The filler removes the strain generated in the silver thin film and the interface between the silver and the substrate during firing,
Alternatively, it is added for the purpose of reduction. It also leads to improved chemical resistance. The flux component may be added with an organometallic compound and / or a glass frit. Pb, B, Si, Zn, Bi, Sn, Cr as metal components,
A material containing Mn, Ti, Al, alkali, alkaline earth or the like is selected. As the organic metal compound, 2-ethylhexanoate, naphthenate, neodecanoate, metal alkoxide, linseed oil fatty acid salt, oleate, stearate, acetylacetone salt and the like are used.

The flux component is added for the purpose of improving the adhesion between the silver conductor thin film and the base material. For example, if the base material is a glass substrate, PbO-B ₂ O ₃ -SiO ₂ , Pb.
A glass frit with a softening point of OB ₂ O ₃ —ZnO ₂ system of about 350 to 600 ° C. may be used. For an alumina substrate, SiO ₂ —Al ₂ O ₃ —CaO, SiO ₂ —PbO—
A CaO-based glass frit having a high softening point may be used.

The above-mentioned resin, solvent, additive flux component and silver component are premixed and then melted and kneaded by a three-roll mill until they are sufficiently homogeneous. A predetermined pattern is obtained by offset printing using the printing ink for a silver conductor circuit thus adjusted. The printing method of the predetermined pattern is offset printing, which may be a flat plate or an intaglio plate, and the predetermined pattern is obtained by transferring the ink from the plate to the blanket or from the blanket to the substrate. 1 pattern ink transfer
If the number of times is not sufficient, overprinting may be performed. By performing this overprinting, the total amount of ink transfer and the film thickness can be increased. Overprinting may be continued, but if backtrapping does not increase the transfer amount during overprinting, prevent backtrapping by curing the ink on the pattern before overprinting. You can The curing method can be curing by irradiation with active energy rays and / or heating. Active energy rays mean ultraviolet rays, infrared rays, and electron rays, and curing proceeds by combining these active energy rays and heating. To further accelerate the curing, it is advisable to add an ultraviolet curable resin, a polymerization initiator and an oxidation accelerator.

When the printed pattern on the base material is not smooth as described above, it is possible to promote the smoothing of the surface by pressing the printed pattern. In the pressing method, a sheet or thin plate is placed on the base material so that force is uniformly applied to the whole base material, and pressure is applied to the whole base material. At this time, increasing the number of presses and the press pressure leads to thickening of the line.

The predetermined pattern obtained by offset printing is subjected to a firing process. The firing temperature is a temperature at which the organic substances contained in the resin component, the solvent component, the additive component and the like must be evaporated, sublimated or decomposed, and is preferably 300 ° C. or higher. Further, in order to improve the adhesion between silver and the base material, the flux component must be melted and a reaction phase must be formed at the interface with the base material, and the temperature must be raised to the temperature required for melting and baked. ..

[0018]

EXAMPLES Examples of the present invention and conventional examples will be described below.

[0019]

[Production Example 1] 16 g of alkyd resin (Dainippon Ink and Chemicals: Becksol EL-8001), 80 g of 0.3 μm spherical metallic silver powder, 4 g of glass frit (1350, Asahi Glass),
After premixing silver 2-ethylhexanoate with 9.3 g, the mixture was kneaded with a three-roll mill to prepare a silver ink.

[0020]

[Production Example 2] 10 g of phenol-modified alkyd resin (manufactured by Dainippon Ink and Chemicals, Inc .: Beccosol 1341), 85 g of 0.3 μm spherical metallic silver powder, glass frit (1370 manufactured by Asahi Glass)
4.5 g of acetyl acetate silver and 10 g of methyl ethyl ketone oxime were kneaded to prepare an ink.

[0021]

[Production Example 3] 10 g of fatty acid-modified epoxy resin (manufactured by Dainippon Ink and Chemicals, Inc .: Beckosol P-786-50), 85 g of 0.5 μm spherical metallic silver powder, 1 g of methyl ethyl ketone oxime,
Ink was prepared by kneading 1.5 g of cobalt naphthenate, 3.5 g of glass frit (1307 manufactured by Asahi Glass Co., Ltd.), and 9 g of silver colloid containing 30% silver.

[0022]

[Production Example 4] To 10 g of rosin (manufactured by Dainippon Ink and Chemicals, Inc .: Heckaside J-896) was added a 30% silver-containing silver colloid terpyol solution to dissolve the rosin, and then 0.3 μm spherical metallic silver powder 40 g, 5 μm 40 g of flaky silver powder, 1 g of methyl ethyl ketone oxime, and 3 g of glass frit (1350 manufactured by Asahi Glass) were mixed and kneaded to prepare an ink.

[0023]

[Production Example 5] Urethane oil (manufactured by Dainippon Ink and Chemicals:
BURNOCK TD-125) 0.1 μm spherical metallic silver powder per 15 g
75 g, eugenol 1 g, thickening varnish 3.5 g lead octylate 1.5 g, bismuth octylate 1 g, silver naphthenate 10 g
Was kneaded to prepare an ink.

[0024]

[Production Example 6] 16 g of alkyd resin (manufactured by Dainippon Ink and Chemicals, Inc .: Beckosol EL-8001), 80 g of spherical metallic silver powder of 0.3 μm, and 4 g of glass frit (manufactured by Asahi Glass: 1350).
After being premixed with each other, they were kneaded with a triple roll to prepare a silver ink.

[0025]

[Production Example 7] Phenol-modified alkyd resin (manufactured by Dainippon Ink & Chemicals, Inc .: Beckol 1341) 10 g, 0.3 μm spherical metallic silver powder 85 g, glass frit (Asahi Glass: 1370)
Knead 4.5 g and 1 g of methyl ethyl ketone oxime,
An ink was made.

[0026]

[Production Example 8] 10 g of fatty acid-modified epoxy resin (manufactured by Dainippon Ink and Chemicals, Inc .: Beckozol P-786-50), 85 g of 0.5 μm spherical metallic silver powder, 1 g of methyl ethyl ketone oxime,
Ink was prepared by kneading 1.5 g of cobalt naphthenate and 3.5 g of glass frit (1307 manufactured by Asahi Glass).

[0027]

Example 1 The inks of Production Examples 1 to 5 were offset-printed on a glass substrate with a predetermined pattern of 50 cm × 50 cm four times by overprinting and then irradiated with ultraviolet rays for 1 minute. Similarly, printing was repeated 4 times and UV irradiation was repeated, and printing was performed 20 times in total. 550 ° C,
Table 1 shows the measurement results of the surface roughness after firing for 10 minutes.

[0028]

[Table 1]

[0029]

Conventional Example 1 Example 1 using the inks of Production Examples 6 to 8
Table 1 shows the result of performing the same operation as.

[0030]

[Example 2] Using the inks of Production Examples 1 to 5, a predetermined pattern of 50 cm x 50 cm was overprinted 10 times by offset printing on a glass substrate, heated and cured at 120 ° C for 5 minutes, and then printed 10 times more. It was The results of measuring the surface roughness are shown in Table 1.

[0031]

Conventional Example 2 Example 2 using the inks of Production Examples 6 to 8
Table 1 shows the result of performing the same operation as.

[0032]

As described above, when the printing ink for silver conductor circuits and the method for forming silver conductor circuits of the present invention are used,
The leveling property is significantly improved, the fine pattern can be prevented from being broken, and the resistance value can be reduced, which is an epoch-making effect.

Claims (13)

[Claims] 1. An alkyd resin, a modified alkyd resin,
A printing ink for a silver conductor circuit, comprising at least one resin component selected from fatty acid epoxy resin, urethanized oil, rosin and maleated oil, and a silver component and a flux component. 2. A solvent component, a leveling agent, a polymerization initiator, an oxidation promoter, an anti-skinning agent, a thickener, a metal chelate resin, a dispersant, and one or more selected from fillers. The printing ink for a silver conductor circuit according to 1. 3. The silver component is a spherical powder having a particle size of 0.05 to 1.0 μm and / or a flake powder having a particle size of 0.5 to 5 μm, and an organometallic compound containing silver and / or a colloid containing silver. Alternatively, the printing ink for a silver conductor circuit according to claim 2. 4. The printing ink for silver conductor circuits according to claim 3, wherein the silver-containing organometallic compound is a carboxylate, an acetylacetate or a metal alkoxide. 5. The flux component is an organometallic compound and / or
Alternatively, the printing ink for silver conductor circuits according to claim 1, claim 2, claim 3 or claim 4, which is a glass frit. 6. An alkyd resin, a modified alkyd resin,
A pattern is offset onto a substrate using a printing ink for a silver conductor circuit containing at least one resin component selected from fatty acid epoxy resin, urethanized oil, rosin and maleated oil, and a silver component and a flux component. From the step of printing, the step of curing this print pattern as it is / or by irradiation with active energy rays and / or heating, the step of overprinting the cured print pattern as it is / or the same pattern, and the step of baking the print pattern. A method for forming a silver conductor circuit, which comprises: 7. The silver conductor circuit printing ink further comprises one or more of a solvent component, a leveling agent, a polymerization initiator, an oxidation accelerator, an anti-skinning agent, a thickener, a metal chelate resin, a dispersant and a filler. 7. The method for forming a silver conductor circuit according to claim 6, containing at least one kind. 8. The silver component is a spherical powder having a particle size of 0.05 to 1.0 μm and / or a flake powder having a particle size of 0.5 to 5 μm, and an organometallic compound containing silver and / or a colloid containing silver. Alternatively, the method for forming a silver conductor circuit according to claim 7. 9. The method for forming a silver conductor circuit according to claim 8, wherein the organometallic compound containing silver is a carboxylate, an acetylacetate or a metal alkoxide. 10. The organometallic compound and / or the flux component
Alternatively, the method for forming a silver conductor circuit according to claim 6, claim 7, claim 8, or claim 9 is a glass frit. 11. The firing temperature is 300 ° C. or higher, 6.
The method for forming a silver conductor circuit according to claim 7, claim 8, claim 9, or claim 10. 12. The method according to claim 6, claim 7, claim 8, claim 9, and claim 9, wherein after the predetermined pattern is printed on the base material, the print pattern is pressed to promote smoothing of the surface of the print pattern. The method for forming a silver conductor circuit according to claim 10 or 11. 13. The method according to claim 6, claim 7, claim 8, claim 9, claim 10, claim 11 or claim 12, wherein the active energy ray is at least one of ultraviolet ray, infrared ray and electron beam. A method for forming the silver conductor circuit described.