JP2025102638A - Coating agent for lift-off process and method for producing laminate - Google Patents

Abstract

To provide a coating agent for a lift-off process including a pattern formation step that does not need exposure to light, the coating agent being excellent in fine line reproducibility, immersion cleanability, printability and stability over time.SOLUTION: A coating agent for a lift-off process including a pattern formation step that does not need exposure to light includes an aqueous resin having acidic groups and inorganic fine particles. A laminate having a coating layer of 1 μm thickness formed on a substrate using the coating agent is treated under the following conditions, and the residual rate of the coating layer, expressed by the following (formula 1) is less than 80 mass%. (Treatment conditions) the laminate is immersed in ion-exchanged water at 40°C for 10 minutes, and then dried in an oven at 80°C for 1 minute. (Formula 1) the residual rate of coating layer (mass%)=(the mass of the coating layer after the treatment)/(the mass of the coating layer before the treatment)×100.SELECTED DRAWING: Figure 2

Description

The present invention relates to a coating agent for lift-off processes and a method for manufacturing a laminate.

Traditionally, lift-off and photolithography methods have been the main methods used to form finely patterned electrode layers on the substrates of electronic components such as semiconductors and solar cell panels. However, from the perspective of improving productivity, the lift-off method (lift-off process), which does not require an etching process, is attracting attention.

The lift-off process generally involves the steps of: (1) forming a resist layer by attaching a photoresist film or applying a photoresist liquid onto a substrate; (2) exposing the resist layer using a photomask; (3) removing unnecessary resist layer using a developer to form a resist pattern; (4) forming an electrode layer on the substrate and the resist layer by sputtering or vapor deposition; and (5) finally removing the resist pattern to form a patterned electrode layer.
However, this method still requires a large number of steps and is a bottleneck in the production of semiconductors and solar cell panels, so there is a demand for further improvements in production efficiency.
In order to improve productivity, a process has been developed in which a patterned resist layer is formed by printing in the above step (1) and does not include the above steps (2) and (3), and this process is also included in the lift-off process. Specifically, (1') a resist film (resist pattern) that is patterned without exposure is formed on a substrate by gravure printing or the like, (2') an electrode layer is formed on the substrate and on the resist layer by sputtering or vapor deposition, and (3') the resist pattern is finally removed to form a patterned electrode layer.

Patent Document 1 proposes a method of applying a pattern of a coating agent containing hydroxypropyl cellulose by gravure printing instead of the resist film formed in steps (1) to (3) of the lift-off process. Patent Document 2 proposes a method of applying a pattern of a coating agent containing hydroxypropyl cellulose and inorganic fine particles by silk screen printing instead of the resist film formed in steps (1) to (3) of the lift-off process. However, the coating agents containing hydroxypropyl cellulose described in Patent Documents 1 and 2 do not contain a resin with an acidic group and have low solubility in water, so there is a concern that they may not be sufficiently removed when washed with water.

JP 2002-200833 A JP 2013-258215 A

The present invention relates to a coating agent for lift-off processes, including a pattern formation process that does not involve exposure, that has excellent fine line reproducibility, immersion cleanability, printability, and stability over time.

As a result of extensive research into the above-mentioned problems, the inventors discovered that the above-mentioned problems could be solved by using the packaging material described below, which led to the creation of the present invention.

That is, the present invention relates to the following [1] to [13].

[1]
A coating agent for a lift-off process including a pattern formation step not involving exposure to light, the coating agent comprising an aqueous resin having an acidic group and inorganic fine particles.

[2]
The coating agent according to [1], wherein after a laminate having a coating layer with a thickness of 1 μm formed using the coating agent on a substrate is treated under the following conditions, the residual rate of the coating layer represented by the following formula (1) is less than 80 mass %. (Treatment conditions)
The laminate was immersed in ion-exchanged water at 40° C. for 10 minutes, and then dried in an oven at 80° C. for 1 minute.
(Formula 1)
Residual rate of coating layer (mass %)=(mass of coating layer after treatment)/(mass of coating layer before treatment)×100

[3]
The coating agent according to [1] or [2], wherein the aqueous resin having an acidic group is a polyvinyl alcohol-based resin (A) having an acidic group.

[4]
The coating agent according to any one of [1] to [3], further comprising an aqueous resin having no acidic group.

[5]
The coating agent according to [4], wherein the mass ratio of the aqueous resin having an acidic group to the aqueous resin not having an acidic group is 9:1 to 1:9.

[6]
The coating agent according to any one of [1] to [5], wherein the inorganic fine particles are at least one selected from the group consisting of calcium carbonate, barium sulfate, magnesium carbonate, silica, titanium oxide, talc, montmorillonite, kaolin, and mica.

[7]
The coating agent according to any one of [1] to [6], wherein the inorganic fine particles have an average particle size of 5 μm or less as measured by a laser scattering method.

[8]
The coating agent according to any one of [1] to [7], wherein a mass ratio of the aqueous resin having an acidic group to the inorganic fine particles is 1:0.2 to 1:3.

[9]
The coating agent according to any one of [1] to [8], further comprising an alcohol-based organic solvent.

[10]
The coating agent according to [9], wherein the alcohol-based organic solvent is at least one selected from the group consisting of methanol, ethanol, isopropanol, and n-propanol.

[11]
The coating agent according to any one of [1] to [10], which has a viscosity of 20 to 500 mPa·s at 25° C. and a solid content of 18% by mass, as measured in accordance with JIS K 7117-1.

[12]
The coating agent according to any one of [1] to [11], wherein the pH of the water in which the inorganic fine particles are extracted is 7.5 to 14.0.

[13]
A step of printing a coating agent for lift-off, which includes an aqueous resin having an acidic group and inorganic fine particles, on a part of a substrate to form a patterned coating layer without exposure to light;
forming an electrode layer on the substrate and on the coating layer to obtain a laminate (C) having a coating layer and an electrode layer on the substrate;
and a step of immersing the laminate (C) having a coating layer and an electrode layer on a substrate in a coating layer removal liquid to remove the coating layer, thereby obtaining a laminate (D) having a patterned electrode layer on a substrate.

The present invention makes it possible to provide a coating agent for lift-off processes, including a pattern formation process that does not require exposure, that has excellent fine line reproducibility, immersion cleanability, printability, and stability over time.

FIG. 2 is an image showing a state in which the coating agent of the present invention is printed on a substrate to form a pattern coating layer in a lift-off process. FIG. 2 is an image showing a state in which an electrode layer is formed on the substrate and the pattern coating layer shown in FIG. 1 in a lift-off process. FIG. 3 is an image showing a state in which an electrode layer is formed on a substrate by removing the pattern coating layer shown in FIG. 2 using a coating layer remover in a lift-off process.

The following describes in detail the embodiments of the present invention, but the embodiments and explanations of the requirements described are merely examples of the embodiments of the present invention, and the present invention is not limited to these contents as long as they do not exceed the gist of the present invention.

<Coating agent for lift-off process>
The coating agent of the present invention is characterized in that it contains an aqueous resin having an acidic group and inorganic fine particles, and is for a lift-off process including a pattern formation step not involving exposure. In a general lift-off process, the method for forming a patterned resist film is not limited, but the "lift-off process" in the present invention is a process in which a coating layer (resist film) made of a coating agent is removed to form a layer having a patterned electrode layer. Specifically, a process in which a patterned resist film is formed using a known printing method such as gravure printing and then removed can be mentioned. In the present invention, by forming a patterned resist film without exposure, an exposure step is not required when forming a patterned resist film, and this process is different from known techniques in which an exposure step is essential.
The present invention relates to a coating agent for a lift-off process including a pattern formation step not involving exposure to light, and is preferably used in a step of printing the coating agent of the present invention on a part of a substrate to form a patterned coating layer, a step of forming electrode layers on the substrate and on the coating layer to obtain a laminate (C) having a coating layer and an electrode layer on the substrate, and a step of immersing the substrate in a coating layer removal liquid to remove the coating layer and the electrode layer to obtain a laminate (D) having a patterned electrode layer on the substrate.

As described above, the lift-off process including a pattern formation step not involving exposure in the present invention is a process in which a layer of resist or the like is patterned using a known printing method such as gravure printing, a film of an electrode material is formed, and the layer of resist or the like is peeled off to form an electrode. Note that the lift-off process is also called the celite process or celite processing, but it is the same process.
The lift-off process including a pattern formation step not involving exposure includes, for example, a step of forming a pattern coating layer by gravure printing the coating agent of the present invention on a portion of a substrate where an electrode layer is not required (FIG. 1), then forming an electrode layer on the substrate and the pattern coating layer by a method such as sputtering using an electrode material such as indium tin oxide (FIG. 2), and finally removing the pattern coating layer using a coating layer removal liquid described later. This allows the electrode layer to be formed only in the required portion (FIG. 3).
The fine line reproducibility, which is the subject of the present invention, is evaluated by evaluating the presence or absence of breaks in the fine lines of the electrode layer finally obtained. By using the coating agent of the present invention, the above-mentioned pattern coating layer can be formed with high precision, thereby suppressing breaks in the electrode layer.
The coating agent of the present invention can be used in a lift-off process including a pattern formation step not involving exposure to light, and is preferably used to form a fine patterned electrode layer on the substrate of an electronic component used in the manufacture of, for example, a semiconductor or solar panel.

The coating agent of the present invention preferably has a viscosity of 20 to 450 mPa·s at 25°C and 18% solids by mass, measured according to JIS K7117-1, more preferably 100 to 300 mPa·s, and even more preferably 200 to 280 mPa·s. When the viscosity of the coating agent at 25°C and 18% solids by mass is within the above range, the viscosity can be adjusted while maintaining the necessary solids when adjusting the viscosity for printing, etc. using a dilution solvent, so that fine line reproducibility, printability, and stability over time are good. In addition, from the viewpoint of suitable viscosity for gravure printing and flexographic printing, which are capable of high-speed printing, the viscosity at 25°C and 10% solids by mass is preferably 20 to 200 mPa·s, and more preferably 50 to 150 mPa·s. When the viscosity of the coating agent at 25°C and 10% solids by mass is within the above range, fine line reproducibility and printability are good.

The coating agent of the present invention contains an aqueous resin having acidic groups and inorganic fine particles, and the acidic groups of the aqueous resin are adsorbed to the surface of the inorganic fine particles to form a highly stable inorganic fine particle dispersion, which has viscoelasticity suitable for high-speed printing and is highly soluble in water. Since the inorganic fine particle dispersion has viscoelasticity suitable for high-speed printing, a highly accurate pattern coating layer can be formed, and breaks in the electrode layer can be suppressed. Therefore, excellent fine line reproducibility, immersion cleanability, and stability over time can be achieved. However, the above action is based on scientific considerations, and the present invention is not limited to only those that exhibit this action.

For the reasons stated above, the coating agent of the present invention is suitable for printing at a printing speed of, for example, 10 m/min or more, and is also suitable for high-speed printing at 50 m/min or more, 100 m/min or more, or 120 m/min or more. The coating agent of the present invention can exhibit excellent fine-line reproducibility even in high-speed printing at a printing speed of 120 m/min or more, particularly in gravure printing, which is highly productive.

<Aqueous Resin Having Acidic Group>
The coating agent of the present invention contains an aqueous resin having an acidic group. The aqueous resin is a resin that is miscible with an aqueous solvent described below and has solubility in an aqueous coating layer removal liquid.
The acidic group is preferably one that has an ability to be adsorbed to inorganic fine particles, and known acidic groups such as sulfonic acid groups, carboxyl groups, and phenolic hydroxyl groups can be used, with the carboxyl group being preferred.

Examples of the resin skeleton of the aqueous resin having an acidic group include polyvinyl alcohol resin, acrylic resin, styrene-acrylic resin, styrene-maleic acid resin, urethane resin, polylactic acid resin, resol-type phenol resin, methylolated urea resin, methylolated melamine resin, polyethylene oxide, polyacrylamide, polysaccharide resin, and modified resins thereof. These aqueous resins having an acidic group can be used alone or in combination of two or more. Among the above, it is preferable to use one or more selected from the group consisting of polyvinyl alcohol resin, acrylic resin, and polysaccharide resin, more preferably polyvinyl alcohol resin and/or polysaccharide resin, and even more preferably polyvinyl alcohol resin.
The polysaccharide resin may be any compound in which two or more known monosaccharides are bonded together, such as cellulose resin, pullulan, starch, agarose, and gum arabic, and is preferably one or more selected from the group consisting of cellulose resin, pullulan, and starch.
In the case of a resin skeleton that does not have an acidic group, acidic groups can be imparted to the resin skeleton by acid modification using a known method.

From the viewpoints of fine line reproducibility, immersion washability, printability, and stability over time, the content of the aqueous resin having acidic groups is preferably 1 to 30 mass% of 100 mass% of the coating agent, more preferably 2 to 15 mass%, and even more preferably 3 to 8 mass%.

<Polyvinyl alcohol resin (A)>
As described above, the aqueous resin having an acidic group is preferably a polyvinyl alcohol resin (A) having an acidic group. The polyvinyl alcohol resin (A) may be any resin having the above-mentioned acidic group and vinyl alcohol unit, and may further be an ethylene-vinyl alcohol resin containing a structural unit derived from ethylene.

The degree of polymerization of the polyvinyl alcohol-based resin (A) is preferably 100 to 3,000, and more preferably 500 to 2,400. When the degree of polymerization of the polyvinyl alcohol-based resin (A) is within the above range, the immersion cleanability, fine line reproducibility, printability, and stability over time are good.

The content of ethylene-derived structural units in the polyvinyl alcohol resin (A) is preferably 1 to 40 mol%, more preferably 3 to 20 mol%, and even more preferably 5 to 15 mol%. When the content of ethylene-derived structural units is within the above range, the immersion cleanability and stability over time are good.

The polyvinyl alcohol resin (A) may be crosslinked with a crosslinking agent. Examples of the crosslinking agent include known crosslinking agents such as isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, oxazoline-based crosslinking agents, and silane coupling-based crosslinking agents, with oxazoline-based crosslinking agents and/or silane coupling-based crosslinking agents being preferred.

The degree of saponification of the polyvinyl alcohol-based resin (A) is represented by the following formula 2, and is preferably 80 mol% or more, more preferably 90 mol%, and more preferably 95 mol%. When the degree of saponification of the polyvinyl alcohol-based resin (A) is within the above range, the immersion cleanability and stability over time are good.
(Formula 2)
Degree of saponification: (number of hydroxyl groups)/{(number of hydroxyl groups)+(number of acetate groups)}×100 [mol %]

Commercially available polyvinyl alcohol resins (A) include, for example, Kuraray Poval 25-88KL (manufactured by Kuraray Co., Ltd., itaconic acid modified polyvinyl alcohol resin), 6-77KL (manufactured by Kuraray Co., Ltd., acid modified polyvinyl alcohol resin), Gohsenex L-3266, and CKS-50 (manufactured by Mitsubishi Chemical Co., Ltd., sulfonic acid modified polyvinyl alcohol resin).

<Aqueous resin having no acidic group>
The coating agent of the present invention preferably further contains an aqueous resin having no acidic groups.
Examples of aqueous resins that do not have an acidic group include polyvinyl alcohol resins, acrylic resins, styrene-acrylic resins, styrene-maleic acid resins, urethane resins, polylactic acid resins, polysaccharide resins, and modified resins thereof. These hydrophilic resins can be used alone or in combination of two or more. Among the above, it is preferable to use a polyvinyl alcohol resin.

From the viewpoints of fine line reproducibility, printability and immersion washability, the content of the aqueous resin without acidic groups is preferably 0.1 to 30 mass% of 100 mass% of the coating agent, more preferably 1 to 15 mass%, and even more preferably 2 to 8 mass%.

When the coating agent of the present invention contains both an aqueous resin having an acidic group and an aqueous resin not having an acidic group, the total content of the aqueous resin having an acidic group and the aqueous resin not having an acidic group is preferably 1 to 30% by mass, more preferably 3 to 20% by mass, and even more preferably 5 to 15% by mass, based on 100% by mass of the coating agent, from the viewpoints of fine line reproducibility, immersion cleanability, printability, and stability over time.

When the coating agent of the present invention contains both an aqueous resin having an acidic group and an aqueous resin not having an acidic group, the mass ratio of the aqueous resin having an acidic group to the aqueous resin not having an acidic group is preferably 9:1 to 1:9, and more preferably 7:3 to 3:7. When the mass ratio is within the above range, fine line reproducibility, immersion washability, printability, and stability over time are good.

<Polyvinyl alcohol resin (B)>
As described above, the coating agent of the present invention preferably contains a polyvinyl alcohol-based resin (B) that does not have an acidic group, in addition to the aqueous resin having an acidic group.
The polyvinyl alcohol-based resin (B) may be any resin having no acidic group and having a vinyl alcohol unit, and may further contain a structural unit derived from ethylene.
As for the preferred embodiments of the degree of polymerization, crosslinking and degree of saponification of the polyvinyl alcohol-based resin (B), the description of the above-mentioned <Polyvinyl alcohol-based resin (A)> can be cited.

The polyvinyl alcohol resin (B) preferably contains structural units derived from ethylene, and the content of structural units derived from ethylene in the polyvinyl alcohol resin (B) is preferably 1 to 40 mol%, more preferably 3 to 20 mol%, and even more preferably 5 to 15 mol%. When the content of structural units derived from ethylene is within the above range, the immersion cleanability and stability over time are good.

<Inorganic fine particles>
The coating agent of the present invention contains inorganic fine particles. Examples of inorganic fine particles include titanium oxide, zinc oxide, zinc sulfide chromium oxide, aluminum particles, mica, bronze powder, chrome vermilion, yellow lead, cadmium yellow, cadmium red, ultramarine, Prussian blue, red iron oxide, yellow iron oxide, iron black, silica, barium sulfate, mica, montmorillonite, kaolin clay, talc, calcium carbonate, magnesium carbonate, etc., and it is preferable that it is at least one selected from the group consisting of calcium carbonate, barium sulfate, magnesium carbonate, silica, titanium oxide, talc, montmorillonite, kaolin, and mica, and it is more preferable that it is calcium carbonate. Calcium carbonate is suitable because it has a small specific gravity and is difficult to settle, which improves the stability of the coating agent, and the viscosity increase of the coating agent due to the oil absorption amount and shape is small.

The average particle size of the inorganic microparticles measured by the laser scattering method is preferably 5 μm or less, more preferably 2 μm or less, even more preferably 1 μm or less, particularly preferably 0.5 μm or less, and most preferably 0.01 to 0.1 μm. When the average particle size of the inorganic microparticles measured by the laser scattering method is within the above range, the fine line reproducibility, printability, and stability over time are improved.

The pH of the water extracted from the inorganic fine particles is preferably neutral to alkaline, more preferably 7.5 to 14, more preferably 7.8 to 12, and even more preferably 8.0 to 9.0. In particular, when the water is alkaline, the acidic groups of the aqueous resin are easily adsorbed, improving fine line reproducibility, immersion cleaning properties, and stability over time. The pH of the water extracted from the inorganic fine particles can be determined by mixing 5 parts of the inorganic fine particles with 100 parts of ion-exchanged water, boiling for 5 minutes, stirring for 30 minutes, and measuring the pH of the supernatant water using a pH meter in accordance with JIS Z 8802.

The specific surface area of the inorganic fine particles is preferably 10 to 100 ^{m 2} /g, and more preferably 10 to 80 m ² /g. When the specific surface area of the inorganic fine particles is within the above range, fine line reproducibility, printability, and stability over time are improved.

The shape of the inorganic fine particles may be any known shape such as spherical, square, cubic, or lamellar, but from the viewpoint of dispersibility, spherical is preferable. When the inorganic fine particles are spherical, the fine line reproducibility, immersion washability, printability, and stability over time are improved.

<Calcium carbonate>
Calcium carbonate includes natural calcium carbonate (heavy calcium carbonate) and synthetic calcium carbonate (light calcium carbonate). Natural calcium carbonate is produced directly from limestone, for example by mechanically crushing and classifying limestone ore. Synthetic calcium carbonate is produced from calcium hydroxide, for example by reacting calcium hydroxide with carbon dioxide.
The calcium carbonate may also be surface-treated with a fatty acid, a resin acid, a silane coupling agent, or the like.

The content of inorganic fine particles in the coating agent is preferably 3 to 20% by mass, and more preferably 5 to 15% by mass, based on 100% by mass of the coating agent. When the content of inorganic particles is within the above range, fine line reproducibility, immersion cleanability, printability, and stability over time are improved.

The mass ratio of the aqueous resin having acidic groups to the inorganic fine particles is preferably 1:0.2 to 1:3, and more preferably 1:0.8 to 1:2. When the mass ratio of the aqueous resin having acidic groups to the inorganic fine particles is within the above range, fine line reproducibility, immersion washability, printability, and stability over time are improved.

<Aqueous Solvent>
The coating agent of the present invention preferably contains an aqueous solvent. The main component of the aqueous solvent is preferably water, but in addition to water, a water-soluble organic solvent can be used. Specifically, depending on the printing conditions (speed, plate depth, design, drying temperature), an alcohol-based organic solvent, a glycol-based organic solvent, etc. can be contained. Among them, from the viewpoints of fine line reproducibility, printability, and stability over time, it is preferable to contain an alcohol-based organic solvent.
In the present invention, the term "mainly water" means that the content of water is the largest in the aqueous solvent, and the term "water-soluble organic solvent" means that the solvent is liquid at 25° C. and has a solubility of 1% by mass or more in water at 25° C.

From the viewpoints of fine line reproducibility, printability and stability over time, the content of the aqueous solvent is preferably 50 to 95 mass% of 100 mass% of the coating agent, and more preferably 70 to 90 mass%.

From the viewpoints of fine line reproducibility, printability, and stability over time, the water content is preferably 70 to 100% by mass, and more preferably 85 to 95% by mass, out of 100% by mass of the aqueous solvent.

From the viewpoints of stability over time, printability, and fine line reproducibility, the content of water-soluble organic solvents such as alcohol-based organic solvents and glycol-based organic solvents is preferably 0.1 to 30% by mass, and more preferably 1 to 15% by mass, based on 100% by mass of the coating agent.

The above-mentioned alcohol-based organic solvents include methanol, ethanol, n-propanol, isopropanol, isobutanol, normal butanol, tertiary butanol, hexanol, octanol, decanol, etc. In the case of a coating method using gravure printing or flexographic printing, at least one selected from the group consisting of methanol, ethanol, n-propanol, and isopropanol is preferred, and n-propanol is even more preferred in terms of stability.

When the aqueous solvent contains water and an alcohol-based organic solvent, the mass ratio of water to alcohol-based organic solvent is preferably 70:30 to 97:3, and more preferably 85:15 to 95:5, from the viewpoints of stability over time, printability, and fine line reproducibility.

Examples of the glycol-based organic solvent include acetylene diol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monooctyl ether, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monobutyl ether, and dibutyl glycol. Among them, at least one selected from the group consisting of diethylene glycol monoethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol monopropyl ether is preferred, and propylene glycol and/or propylene glycol monopropyl ether is more preferred. These water-soluble organic solvents may be used alone or in combination of two or more.

When the aqueous solvent contains water and a glycol-based organic solvent, the mass ratio of water to glycol-based organic solvent is preferably 100:10 to 100:0.2, and more preferably 100:5 to 100:0.2. When the mass ratio of water to glycol-based organic solvent is within the above range, fine line reproducibility, printability, and stability over time are improved.

<Additives>
The coating agent of the present invention may contain known additives such as an isocyanate compound, a silane coupling agent, a dispersant, a stabilizer, a viscosity adjuster, a colorant, etc., within the scope of not impairing the effects of the present invention.

<Method of manufacturing coating agent for lift-off process>
The coating agent of the present invention can be produced, for example, by mixing an aqueous resin having an acidic group, inorganic fine particles, and, if necessary, an aqueous solvent, etc., dispersing the inorganic fine particles using a dispersing machine, and mixing the obtained dispersion with various additives, organic solvents, etc. As the dispersing machine, for example, a roller mill, a ball mill, a pebble mill, an attritor, or a sand mill that are commonly used can be used.

<Formation of Coating Layer>
The coating agent of the present invention is coated on a substrate, and a coating layer can be formed by removing volatile components. The coating method is preferably printing, and examples of the printing method include conventionally known methods such as gravure printing, flexographic printing, dipping, roll coating, screen printing, and spraying, but gravure printing and/or flexographic printing are preferred, and gravure printing is more preferred. That is, the coating agent of the present invention is preferably for gravure printing or flexographic printing, and more preferably for gravure printing.

For example, the coating agent is diluted with a diluting solvent to a viscosity and concentration suitable for gravure printing, and is supplied to each printing unit alone or in a mixture to be applied. Thereafter, the coating film is fixed by drying in an oven or the like to obtain a coating layer.
The thickness of the coating layer is preferably 0.1 μm to 10 μm, more preferably 0.2 to 5 μm, even more preferably 0.3 to 3 μm, and particularly preferably 0.6 to 2 μm. The printing speed is not particularly limited, but from the viewpoint of productivity, it is preferably 10 to 300 m/min, more preferably 50 to 200 m/min, and even more preferably 80 to 150 m/min.

<Gravure printing>
(Photogravure version)
The gravure plate is a cylindrical metal plate. The method of forming cells in the gravure plate includes engraving and etching (photosensitive film coating-exposure-development-etching). In terms of making the contour of the coating layer sharp, the etching method is preferred because it can form cells along the edge of the image. Furthermore, in the etching method, the accuracy of the cells can be improved by increasing the resolution during exposure. As the platemaking device, for example, the laser automatic platemaking system FXIII (laser drawing resolution: face length direction 3200 dpi/circumferential direction 12800 dpi) manufactured by Think Laboratory Co., Ltd. or the laser platemaking device/electronic engraving machine DIGILAS5000 manufactured by MDC Co., Ltd. is preferably used, and the laser platemaking device/electronic engraving machine DIGILAS5000 manufactured by MDC Co., Ltd. is more preferably used.

The line count, which is a parameter equivalent to the printing resolution, is preferably 200 to 350 lines/inch. If the line count is 200 or more lines/inch, the edge shape of the printed area will be good, which tends to improve fine line reproducibility, and if it is 350 or less lines/inch, the cell openings will be large, which will improve ink transfer and tend to improve fine line reproducibility.

The plate depth, which is a parameter that controls the amount of ink transfer, is preferably 15 to 25 μm. If the plate depth is 15 μm or more, smearing of the coating layer can be suppressed, which tends to improve fine-line reproducibility. If the plate depth is 25 μm or less, the amount of coating agent applied is appropriate, which suppresses bleeding of the coating layer, which tends to improve fine-line reproducibility. In addition, by setting the plate depth to 25 μm or less, the amount of coating agent applied can be reduced, which reduces drying energy and improves printing speed, i.e. productivity.

In the case of slow-drying water-based inks or polyester films with good wet spreadability, the pattern line width of the printed matter tends to be wider than the plate pattern line width due to the coating agent wetting and spreading on the film. In such cases, from the viewpoint of suppressing bleeding due to the wetting and spreading of the coating layer, the ratio of the plate pattern line width to the target pattern line width (plate pattern line width/target pattern line width) is preferably 75-90%, and more preferably 77-85%. When plate pattern line width/target pattern line width is within the above range, good thin line reproducibility is achieved.

(printing machine)
In the gravure printing press, one printing unit is equipped with the gravure plate and doctor blade. There are many printing units, and printing units corresponding to organic solvent-based printing inks and picture inks can be set, and each unit has an oven drying unit. Printing is performed by rotary printing, and a roll-to-roll printing method is used. The type of plate and the type of doctor blade are appropriately selected according to the specifications.

<Method for producing laminate (D) having a patterned electrode layer on a substrate>
A method for producing a laminate having a patterned electrode layer on a substrate using the coating agent for a lift-off process of the present invention is characterized by the following steps.
(1) A step of printing a coating agent for lift-off, which contains an aqueous resin having an acidic group and inorganic fine particles, on a part of a substrate to form a patterned coating layer without exposure to light; (2) A step of forming an electrode layer on the substrate and on the coating layer to obtain a laminate (C) having a coating layer and an electrode layer on the substrate; (3) A step of immersing the laminate (C) having a coating layer and an electrode layer on the substrate in a coating layer removal liquid to remove the coating layer and the electrode layer formed on the coating layer.

<Usage example>
The laminate (D) having an electrode layer patterned on a substrate can be used as a part of a semiconductor or a solar cell panel, and can be used, for example, as "substrate/transparent conductive film (-)" in the exemplary laminate structure of a perovskite solar cell, "substrate/transparent conductive film (-)/metal oxide layer/perovskite/hole transport layer/electrode (+)."

<Base material>
The substrate is not particularly limited, but in the application of next-generation solar cells, which have been developed in recent years to realize a decarbonized society, it is preferable to use a lightweight and flexible plastic film as the substrate. As the plastic film, polyester film, polyimide film, etc. are preferable for weather resistance, and examples of polyester films include polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). In order to provide the laminate with water vapor barrier properties, the substrate itself may have a barrier layer such as a transparent deposition layer of an inorganic oxide. In addition, the substrate may have a surface treatment such as corona treatment or frame treatment to provide easy adhesion for printing and post-processing, or may have a coating layer.

<Electrode layer>
The electrode layer can be formed by forming a conductor on the substrate by a dry method such as vapor deposition or sputtering. Among them, it is preferable to form the electrode layer by sputtering, which is excellent in forming a large-area film suitable for mass production. Examples of the conductor include metals such as Al, Ti, Pb, Ni, Cu, Ag, Au, Cr, Sn, and In, and oxides such as ITO, Al2O3, and SiO2. In particular, ITO, which is a transparent electrode and Pb-free, is suitable for use in next-generation solar cells.

<Method of Removing Coating Layer>
The coating layer is exposed to the coating layer removal liquid by an appropriate method. For example, the coating layer removal liquid is sprayed onto the conductor covering the coating layer, or the coating layer and the conductor covering the coating layer are immersed in the coating layer removal liquid, thereby exposing the coating layer to the coating layer removal liquid. The preferred method for removing the coating layer is immersion in the coating layer removal liquid.

<Coating Layer Removal Solution>
As the coating layer removal liquid, it is preferable to use water from the viewpoint of environmental friendliness, such as facilitating waste liquid treatment. In addition, as the coating layer removal liquid, a mixed liquid containing a water-soluble organic solvent can also be used. Examples of the water-soluble organic solvent include alcohols such as methanol, ethanol, 2-propanol, and 1,2-propanediol; glycol ethers such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethyl cellosolve, propylene glycol monopropyl ether, propylene glycol monoisopropyl ether, butyl cellosolve, ethylene glycol monoisobutyl ether, propylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and dipropylene glycol monomethyl ether; and cyclohexanone.
It is also preferred that the coating layer removal liquid contains at least one selected from the group consisting of nonionic surfactants, anionic surfactants, and cationic surfactants. When a mixture of the above solvents is used, the water content in the mixture is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, based on 100% by mass of the mixture. When the water content in the mixture is within the above range, fine line reproducibility tends to be improved.

<Residual rate of coating layer>
The residual rate of the coating layer in the present invention is a value represented by the following formula 1 after a laminate in which a coating agent is applied to a substrate to form a coating layer having a thickness of 1 μm is treated under the following conditions. The residual rate of the coating layer is preferably less than 80 mass%, more preferably less than 50 mass%, even more preferably less than 10 mass%, and particularly preferably less than 5 mass%. When the residual rate of the coating layer is within the above range, the removal rate of the coating layer and unnecessary electrode layer portions is improved during immersion cleaning, and thus fine line reproducibility tends to be improved.
(Processing conditions)
The laminate was immersed in ion-exchanged water at 40° C. for 10 minutes, and then dried in an oven at 80° C. for 1 minute.
(Formula 1)
Residual rate of coating layer (mass %)=(mass of coating layer after treatment)/(mass of coating layer before treatment)×100

In an embodiment of the coating agent of the present invention that satisfies the requirement for the residual rate of the coating layer represented by the above (Formula 1), the aqueous resin having an acidic group preferably has a sulfonic acid group, a carboxyl group, or a phenolic hydroxyl group as the acidic group, and the resin skeleton of the aqueous resin having an acidic group is preferably, for example, a polyvinyl alcohol-based resin (A), an acrylic resin, a styrene-acrylic resin, a styrene-maleic acid resin, a urethane resin, a polylactic acid resin, a resol-type phenolic resin, a methylolated urea resin, a methylolated melamine resin, a polyethylene oxide, a polyacrylamide, a polysaccharide-based resin, or a modified resin thereof, and the use of the resin having the above acidic group and resin skeleton improves the solubility in the coating agent removal liquid, thereby increasing the tendency to satisfy the above-mentioned residual rate of the coating layer.
In addition, the inorganic fine particles are preferably at least one selected from the group consisting of calcium carbonate, barium sulfate, magnesium carbonate, silica, titanium oxide, talc, montmorillonite, kaolin, and mica, and the shape of the inorganic fine particles is preferably spherical. When the inorganic fine particles are in the above-mentioned form, the dispersibility of the resin having an acidic group and the inorganic fine particle dispersion formed by the inorganic fine particles is improved, and the solubility in water is improved, so that the tendency to satisfy the residual rate of the coating layer is enhanced.

The content of the aqueous resin having an acidic group in the coating agent is preferably 1 to 30 mass %, more preferably 2 to 15 mass %, and even more preferably 3 to 8 mass %, based on 100 mass % of the coating agent.
Furthermore, the content of inorganic fine particles in the coating agent is preferably 3 to 20 mass% in 100 mass% of the coating agent, and the mass ratio of the aqueous resin having an acidic group to the inorganic fine particles is preferably 1:0.2 to 1:3.
When inorganic fine particles are dispersed in an aqueous resin having acidic groups, their solubility in solvents such as water is improved. Therefore, when the mass ratio of the aqueous resin having acidic groups and the aqueous resin having acidic groups to the inorganic fine particles in the coating agent is within the above range, the tendency to satisfy the above-mentioned residual rate of the coating layer is increased.

The coating agent of the present invention preferably further contains an aqueous resin having no acidic groups, and the aqueous resin is preferably a polyvinyl alcohol resin (B), and the polyvinyl alcohol resin (B) preferably contains a structural unit derived from ethylene, and the content of the structural unit derived from ethylene in the polyvinyl alcohol resin (B) is preferably 1 to 40 mol%, more preferably 3 to 20 mol%, and even more preferably 5 to 15 mol%. When dried, the aqueous resin tends to show a property of being difficult to dissolve in water due to hydrogen bonds. Therefore, by using resins with different structures in combination, the hydrogen bond strength is reduced, and the tendency to satisfy the residual rate of the coating layer is increased. In particular, by using a polyvinyl alcohol resin (B) containing a structural unit derived from ethylene as an aqueous resin having no acidic groups, the total amount of hydroxyl groups in the coating layer is reduced, and the tendency to satisfy the residual rate of the coating layer is increased.

The content of the aqueous resin having no acidic group is preferably 0.1 to 30 mass%, and particularly preferably 2 to 8 mass%, in 100 mass% of the coating agent. The mass ratio of the aqueous resin having an acidic group to the aqueous resin having no acidic group is preferably 9:1 to 1:9, and particularly preferably 7:3 to 3:7.
When the content of the aqueous resin that does not have acidic groups and the mass ratio of the aqueous resin that has acidic groups to the aqueous resin that does not have acidic groups are within the above ranges, the balance between the hydrogen bonding strength and the dispersibility of the inorganic fine particles is good, and the tendency to satisfy the above-mentioned residual rate of the coating layer is increased.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Note that parts and percentages in the present invention represent parts by mass and percentages by mass unless otherwise noted.

<Method for measuring pH of water extracted with inorganic fine particles>
Five parts of inorganic fine particles and 100 parts of ion-exchanged water were mixed and heated at 100° C. for 5 minutes. The mixture was then cooled to room temperature, and ion-exchanged water was added so that the total amount of the inorganic fine particles and the ion-exchanged water was 105 parts. After stirring, the pH was measured using a multi-pH meter (manufactured by AS ONE CORPORATION) in accordance with JIS Z 8802.

<Viscosity measurement>
The viscosity of the coating agent was measured under the following conditions in accordance with JIS K 7117-1 using a Viscometer TUB-10 manufactured by Toki Sangyo Co., Ltd. When the solid content concentration was low, the solid content was adjusted by leaving the coating agent in a storage container with the lid open and allowing the solvent to evaporate.
Measurement conditions
Rotor: M1
・Rotation speed: 6 rpm
Liquid temperature: 25°C
Solid content at time of viscosity measurement before dilution: 18% by mass
Solid content at the time of viscosity measurement after dilution: 10% by mass

<Weight average molecular weight measurement>
The weight average molecular weight was determined as a converted molecular weight using polyethylene glycol as a standard substance. The measuring device used was a GPC device: Shodex GPC-401 manufactured by Showa Denko K.K. The column was a Shodex OHpak LB-805 manufactured by Showa Denko K.K. The detector was an RI (differential refractometer). The eluent used was a 0.1N _NaNO3 aqueous solution, and the column temperature was 35°C and the flow rate was 3 mL/min.

<Preparation of resin solution>
(Preparation example 1) Resin solution V01
12 parts of polyvinyl alcohol resin PVA1 and 88 parts of ion-exchanged water were heated with stirring, and the mixture was heated and stirred at 90° C. for 1 hour. After that, heating was stopped and stirring was continued until the temperature returned to room temperature, to obtain resin solution V01.

(Preparation Examples 2 to 6) Resin solutions V02 to 06
Resin solutions V02 to V06 were obtained in the same manner as in Preparation Example 1, except that the raw materials and compounding ratios were changed to those shown in Table 1. The properties of the raw materials used in Preparation Examples 1 to 6 are as follows.
Polyvinyl alcohol resin PVA1: itaconic acid modified polyvinyl alcohol, polymerization degree = 1800, viscosity (20°C, 4% aqueous solution) = 25 mPa·s, saponification degree = 88%, solid content 100%
Polyvinyl alcohol resin PVA2: Sulfonic acid modified polyvinyl alcohol, polymerization degree = 300, viscosity (20°C, 4% aqueous solution) = 2.5 mPa·s, saponification degree = 98%, solid content 100%
Polyvinyl alcohol resin PVA3: ethylene vinyl alcohol resin, ethylene content: 8 mol%, polymerization degree = 400, viscosity (20°C, 4% aqueous solution) = 4 mPa·s, saponification degree = 98%, solid content 100%
Polyvinyl alcohol PVA4: Manufactured by Kuraray Co., Ltd., Poval 28-98, unmodified polyvinyl alcohol, polymerization degree = 1700, viscosity (20°C, 4% aqueous solution) = 28 mPa·s, saponification degree = 98%, solid content 100%
Cellulose-based resin CE1: Daicel Corporation, CMC Daicel #2200, carboxymethyl cellulose, viscosity (25°C, 1% aqueous solution) = 2200 mPa·s, solid content 100%
Cellulose-based resin CE2: Nippon Soda Co., Ltd., HPC-SL, hydroxypropyl cellulose, viscosity (25°C, 10% aqueous solution) = 150 mPa·s, solid content 100%

<Production of coating agent for lift-off process>
(Example 1) Coating agent C1 for lift-off process
75.0 parts of resin solution V01, 9.0 parts of calcium carbonate, 8.0 parts of ion-exchanged water, and 8.0 parts of n-propyl alcohol were mixed and dispersed in a bead mill for 20 minutes to obtain a coating agent C1 for lift-off process.

(Examples 2 to 29, Comparative Examples 1 and 2) Coating agents C2 to C31 for lift-off process
Coating agents C2 to C31 for lift-off process were obtained in the same manner as in Example 1, except that the raw materials and compounding ratios were changed to those shown in Table 2. The properties of the raw materials used are as follows. The pH is the pH of the respective extraction water.
Calcium carbonate CA1: manufactured by Shiraishi Calcium Co., Ltd., Homocal D, synthetic calcium carbonate, average particle size 0.08 μm, pH 8.6, solid content 100%
Calcium carbonate CA2: average particle size 0.3 μm, pH 8
Calcium carbonate CA3: average particle size 1.5 μm, pH 9
Calcium carbonate CA4: average particle size 4.5 μm, pH 8.9
Silica: Fuji Silysia Chemical Co., Ltd., Silica 310, gel method silica, average particle size 1.7 μm, pH 7.5
Barium sulfate: Sakai Chemical Industry Co., Ltd., Variace B31, precipitated barium sulfate, average particle size 0.3 μm, pH 7
Montmorillonite: Kunimine Kogyo Co., Ltd., Kunipia F, swelling montmorillonite, particle aspect ratio 500, particle thickness 1 μm, average particle diameter 0.5 μm, pH 8 to 8.5
Titanium oxide: Titanix JR-808, manufactured by Teika Corporation, average particle size 2.3 μm, pH 7.7
Mica: average particle size 6 μm, aspect ratio 100, specific surface area 9 m ² /g, pH 8
Kaolin: average particle size 1.2 μm, aspect ratio 100, specific surface area 10 m ² /g, pH 6
Talc: Specialty Minerals, AlBACAR 5970, average particle size 1.9 μm, pH 8

<Production of Laminate Using Coating Agent of Example 1>
A dilution solvent (water/n-propyl alcohol=92/8) was added to the coating agent C1 for lift-off process so that the solid content of the coating agent was 10%, and the mixture was stirred and mixed. Thereafter, a coating layer was formed by printing the diluted lift-off process coating agent C1 on the corona-treated surface of the corona-treated biaxially stretched polyester film (PET) film (thickness 50 μm) using a gravure printing machine equipped with a gravure plate having a fine-line stripe pattern with line widths of 20 μm, 50 μm, 100 μm, and 200 μm and a plate depth of 20 μm (cell formation method: corrosion method, laser platemaking device D1: MDC laser platemaking device/electronic engraving machine DIGILAS5000, number of lines: 300 lines/inch, plate depth: 20 μm, plate pattern line width/target pattern line width: 90%) under conditions of a printing speed of 120 m/min and an in-line oven temperature of 80° C., thereby obtaining an intermediate laminate having fine-line patterns with line widths of 20 μm, 50 μm, 100 μm, and 200 μm using the lift-off process coating agent.
On the surface of the intermediate laminate on which the fine line pattern was printed using the coating agent for the lift-off process, and on the substrate not having the pattern, ITO was deposited by sputtering under conditions of a vacuum degree of 10 ^-4 Pa and an applied voltage of 5.1 kV using an SPC series manufactured by Canon Anelva Corporation to form a transparent electrode layer having a thickness of 0.4 μm, thereby obtaining a laminate. Note that this laminate has a component part of substrate/coating layer/electrode layer and a component part of substrate/electrode layer.

<Production of Laminates Using Coating Agents of Examples 2 to 29 and Comparative Examples 1 and 2>
A laminate was produced in the same manner as in <Production of laminate using coating agent of Example 1>, except that the coating agent for lift-off process and dilution solvent in Table 2 were used.

<Production of Laminates of Examples 30 to 43>
A laminate was produced in the same manner as in <Production of a laminate using the coating agent of Example 1>, except for using the coating agent and plate for the lift-off process in Table 3. The plate production apparatus used is as follows.
・Laser plate making device D1: MDC DIGILAS5000
Laser plate making device D2: HelioKlischograph K500 G4 manufactured by Heliograph Japan
・Laser plate making device D3: Think Laboratory newFXIII

<Evaluation of Coating Agent and Laminate>
The obtained coating agent and laminate were evaluated as follows. The results are shown in Tables 2 and 3.

<Immersion cleaning properties>
The obtained laminate was cut into a size of 10 mm x 50 mm, immersed in 40°C ion-exchanged water for 10 minutes, and then dried in an oven at 80°C for 1 minute. The remaining rate (mass%) of the coating layer before and after washing was calculated and evaluated using the following formula 1. AA to C are practical levels.
When the coating agent of the present invention is used in a lift-off process, in order to achieve high productivity, it is preferable to remove the coating layer only by immersion in ion-exchanged water, so the immersion cleanability test of the present invention was performed by only immersion in ion-exchanged water. A conventional cleanability test is a test method in which the coating layer is removed by applying pressure from a water flow or the like, but the immersion cleanability test of the present invention differs from the conventional cleanability test in that no pressure from a water flow or the like is applied, and is a strict test method that requires higher solubility in the cleaning solution.
(Formula 1)
Residual rate of coating layer (mass %)=(mass of coating layer after treatment)/(mass of coating layer before treatment)×100
AA: Residual rate (mass%) of coating layer is less than 5% by mass A: Residual rate (mass%) of coating layer is 5% by mass or more and less than 10% by mass B: Residual rate (mass%) of coating layer is 10% by mass or more and less than 50% by mass C: Residual rate (mass%) of coating layer is 50% by mass or more and less than 80% by mass D: Residual rate (mass%) of coating layer is 80% by mass or more

<Fine line reproducibility>
After the immersion cleaning test of the obtained laminate, the thin stripe pattern was visually observed and evaluated according to the following criteria, with AA to C being practical levels.
AA: No breaks in any stripe pattern portion. A: There is a break in the 20 μm thin line stripe pattern portion, but there are no breaks in the 50 μm, 100 μm, and 200 μm thin line stripe pattern portions. B: There is a break in the 50 μm thin line stripe pattern portion, but there are no breaks in the 100 μm and 200 μm thin line stripe pattern portions. C: There is a break in the 100 μm thin line stripe pattern portion, but there are no breaks in the 200 μm thin line stripe pattern portion. D: There is a break in the 200 μm stripe pattern portion.

<Stability over time>
The coating agent for lift-off process was filled into a 225 g mayonnaise bottle (body diameter 62 mm/total length 109 mm), and layer separation was confirmed after 7 days at 40°C and evaluated according to the following criteria. The length in each criterion is the layer length measured when the mayonnaise bottle is viewed from the horizontal direction. A to C are practical levels.
A: No layer separation B: Layer separation occurs, and a layer of less than 10 mm is formed C: Layer separation occurs, and a layer of 10 mm or more and less than 20 mm is formed D: Layer separation occurs, and a layer of 20 mm or more is formed

<Printability>
The coating agent for the lift-off process diluted with the dilution solvent shown in Table 2 was poured into the printing ink container of a printing press, and the plate was rotated at a printing speed of 120 m/min for 60 minutes, after which the colored area of the non-image area on the plate was visually evaluated, and the printability was evaluated according to the following criteria. Note that in Examples 1 to 29 and Comparative Examples 1 and 2, plate D1 was used, and in Examples 30 to 45, the plates shown in Table 3 were used. Note that A to C are practical levels.
A: No coloring in non-image areas.
B: Coloring of non-image areas occurs, and the colored area is less than 5% by area. C: Coloring of non-image areas occurs, and the colored area is 5% to less than 30% by area. D: Coloring of non-image areas occurs, and the colored area is 30% or more by area.

From the above results, since Comparative Example 1 did not contain an aqueous resin having an acidic group, the fine line reproducibility, immersion cleanability, printability, and temporal stability were poor. Since Comparative Example 2 did not contain inorganic fine particles, the fine line reproducibility and immersion cleanability were poor.
On the other hand, in the examples, since the aqueous resin having an acidic group and inorganic fine particles were contained, the fine line reproducibility, immersion cleanability, printability and stability over time were good.

Claims (13)

A coating agent for a lift-off process including a pattern formation step not involving exposure to light,
A coating agent comprising an aqueous resin having an acidic group and inorganic fine particles. 2. The coating agent according to claim 1, wherein after a laminate having a coating layer having a thickness of 1 μm formed using the coating agent on a substrate is treated under the following conditions, a residual rate of the coating layer represented by the following formula (1) is less than 80 mass%.
(Processing conditions)
The laminate was immersed in ion-exchanged water at 40° C. for 10 minutes, and then dried in an oven at 80° C. for 1 minute.
(Formula 1)
Residual rate of coating layer (mass %)=(mass of coating layer after treatment)/(mass of coating layer before treatment)×100 The coating agent according to claim 1 or 2, wherein the aqueous resin having an acidic group is a polyvinyl alcohol-based resin (A) having an acidic group. The coating agent according to claim 1 or 2, further comprising an aqueous resin having no acidic groups. The coating agent according to claim 4, in which the mass ratio of the aqueous resin having an acidic group to the aqueous resin not having an acidic group is 9:1 to 1:9. The coating agent according to claim 1 or 2, wherein the inorganic fine particles are at least one selected from the group consisting of calcium carbonate, barium sulfate, magnesium carbonate, silica, titanium oxide, talc, montmorillonite, kaolin, and mica. The coating agent according to claim 1 or 2, wherein the inorganic fine particles have an average particle size of 5 μm or less as measured by a laser scattering method. The coating agent according to claim 1 or 2, in which the mass ratio of the aqueous resin having acidic groups to the inorganic fine particles is 1:0.2 to 1:3. The coating agent according to claim 1 or 2, further comprising an alcohol-based organic solvent. The coating agent according to claim 9, wherein the alcohol-based organic solvent is at least one selected from the group consisting of methanol, ethanol, isopropanol, and n-propanol. The coating agent according to claim 1 or 2, which has a viscosity of 20 to 450 mPa·s at 25°C and 18% solids by mass, measured according to JIS K 7117-1. The coating agent according to claim 1 or 2, wherein the pH of the water from which the inorganic fine particles are extracted is 7.5 to 14.0. A step of printing a coating agent for lift-off, which includes an aqueous resin having an acidic group and inorganic fine particles, on a part of a substrate to form a patterned coating layer without exposure to light;
A method for producing a laminate, comprising: a step of forming electrode layers on the substrate and on the coating layer to obtain a laminate (C) having a coating layer and an electrode layer on the substrate; and a step of immersing the laminate (C) having the coating layer and the electrode layer on the substrate in a coating layer removal liquid to remove the coating layer, thereby obtaining a laminate (D) having a patterned electrode layer on the substrate.