JP7811097B2 - Undercoat paint for plating, substrate with coating layer, and method for manufacturing plated product using these - Google Patents

Description

The present invention relates to a primer coating for plating, a substrate with a coating layer, and a method for producing plated products using these.

In recent years, fine-line printing of electrode materials for printed circuit boards, touch sensors, and the like has progressed in order to achieve higher integration and reduce visibility. Touch sensors are also increasingly being made three-dimensional, rather than just flat. A known method for providing electrode materials on substrates with complex three-dimensional shapes is to form the electrode materials on the substrate and then shaping them three-dimensionally by vacuum forming or other methods. Metal materials such as copper, silver, and gold, or non-flexible metal oxide materials such as indium tin oxide, are generally used for electrode materials used in printed circuit boards and touch sensors.
However, when a substrate having an electrode member made of such a non-flexible material is three-dimensionally molded, the non-flexible material cannot follow the deformation of the substrate, resulting in a problem of breakage.
On the other hand, it is known to use flexible materials such as conductive paste as electrode members, but even flexible materials such as conductive paste lack extensibility, and when attempting to form three-dimensional shapes after printing fine lines on a substrate, problems arise such as broken lines or increased resistance.

As a means to solve these problems, Patent Document 1 describes a plated product that has been three-dimensionally molded using a specific coating layer. Specifically, the coating layer (plating base coating layer) is formed on a substrate and is composed of reducible or conductive polymer microparticles, a binder (synthetic resin), and an inorganic filler. The binder (synthetic resin) content is in the range of 0.1 to 60 parts by weight per 1 part by weight of reducible or conductive polymer microparticles, and the inorganic filler content is in the range of 0.05 to 1.5 parts by weight per 1 part by weight of synthetic resin, in terms of solids content. The coating layer is then used to form a straight line with a line width of 1.0 mm by screen printing. The substrate with the coating layer is then biaxially stretched to a stretch ratio of 200 to 800% relative to its original size, followed by plating, to obtain a three-dimensional plated product with a plating film on the coating layer.

Patent Document 2 also describes a plating undercoat layer that exhibits excellent crack-free plating deposition and adhesion. Specifically, the plating undercoat layer is composed of conductive or reducing polymer microparticles, a synthetic resin, and an inorganic filler. The synthetic resin content is 0.1 to 60 parts by mass per 1 part by mass of the polymer microparticles, and the inorganic filler content is 0.1 to 0.7 parts by mass per 1 part by mass of the synthetic resin, in terms of solids content. The synthetic resin in the plating undercoat layer contains a synthetic resin with a Tg of 30°C or less in an amount of 15% by mass or more, in terms of solids content. The patent proposes that a straight line with a line width of 1.0 mm is formed by screen printing using the plating undercoat layer, and the substrate with the coating layer is then stretched and plated. This results in a plated product with excellent plating deposition and adhesion on the plating undercoat layer, without the occurrence of cracks in the coating.

JP 2011-74407 A JP 2012-241208 A

However, with the changing times, there is a demand for even thinner lines in electrode components, specifically line widths of 50 μm or less. However, while it has been shown that the use of the plating primer coating layer described in Patent Documents 1 and 2 makes it possible to print and draw fine lines with a line width of 1.0 mm, it is not possible to print line widths of 50 μm or less, and there is no known primer coating for plating that can print and draw fine lines with a line width of 50 μm or less.

Furthermore, as wires become thinner, the area of contact between the substrate with a coating layer and the metal plating film decreases, and the adhesion between the substrate with a coating layer and the metal plating film described in Patent Documents 1 and 2 is not sufficient for drawing thin wires of 50 μm or less, so further improvements in adhesion are required.

The present invention aims to provide an undercoat paint for plating that enables fine line printing with a line width of 50 μm or less and prevents the plating undercoat layer from breaking even when the substrate with the coating layer is stretched after printing the fine line with a line width of 50 μm or less.
Another object of the present invention is to provide a substrate with a coating film layer that has excellent adhesion to a metal plating film and plating deposition even when the line width is 50 μm or less, by using the undercoat coating for plating of the present invention.
A further object of the present invention is to provide a method for producing plated articles using the undercoat coating for plating of the present invention.

The plating primer coating according to claim 1 of the present invention is a plating primer coating for forming a plated object having a three-dimensional shape, and is characterized in that the plating primer coating contains conductive or reducing polymer microparticles, synthetic resin, and inorganic filler, the polymer microparticles are polypyrrole microparticles, the synthetic resin is a polyester-based resin, the inorganic filler is one of silica particles, carbon black, and titanium oxide, the content of the conductive or reducing polymer microparticles is 5 parts by mass or more and 19 parts by mass or less per 100 parts by mass of synthetic resin, in terms of solid content, and the content of the inorganic filler is 11 parts by mass or more and 45 parts by mass or less per 100 parts by mass of synthetic resin, in terms of solid content, and is capable of forming a plating primer coating layer having a line width of 50 μm or less .
The substrate with a coating layer according to claim 2 of the present invention is characterized in that a plating undercoat coating layer made of the undercoat paint for plating according to claim 1 is formed on the substrate, and the line width of the plating undercoat coating layer is 50 μm or less .
A method for producing a plated product according to a third aspect of the present invention is characterized in that the substrate with the coating layer according to the second aspect is three-dimensionally formed, and then electroless plating is performed.

The present invention can provide a primer coating for plating that enables fine line printing with a line width of 50 μm or less and prevents the plating primer coating layer from breaking even when the substrate with the coating layer is stretched after printing of fine lines with a line width of 50 μm or less. Furthermore, by using the primer coating for plating of the present invention, a substrate with a coating layer that has excellent adhesion to the metal plating film and plating deposition even with a line width of 50 μm or less and that does not break even when three-dimensionally molded can be provided.
It is also possible to provide a method for producing a plated product using the undercoat paint for plating.

The present invention relates to a primer coating for plating containing conductive or reducing polymer microparticles, synthetic resin, and inorganic filler, characterized in that the content of the conductive or reducing polymer microparticles is, in terms of solid content, 5 to 19 parts by mass per 100 parts by mass of synthetic resin, and the content of the inorganic filler is, in terms of solid content, 11 to 45 parts by mass per 100 parts by mass of synthetic resin.

<Plating primer>
(Conductive or reducing polymer fine particles)
The conductive or reducing polymer fine particles used in the present invention are not particularly limited as long as they are a polymer having a conductive or reducing π-conjugated double bond, and examples thereof include pyrrole, N-methylpyrrole, N-ethylpyrrole, N-phenylpyrrole, N-naphthylpyrrole, N-methyl-3-methylpyrrole, N-methyl-3-ethylpyrrole, N-phenyl-3-methylpyrrole, N-phenyl-3-ethylpyrrole, 3-methylpyrrole, 3-ethylpyrrole, 3-n-butylpyrrole, 3-methoxypyrrole, 3-ethoxypyrrole, 3-n-propoxypyrrole, 3-n-butoxypyrrole, 3-phenylpyrrole, 3-toluylpyrrole, 3-naphthylpyrrole, 3-phenoxypyrrole, 3-methylphenoxypyrrole, 3-aminopyrrole, 3-dimethylaminopyrrole, 3-diethylaminopyrrole, 3-diphenylaminopyrrole, 3-methylphenylaminopyrrole, and 3-phenylnaphthylaminopyrrole. aniline derivatives such as aniline, o-chloroaniline, m-chloroaniline, p-chloroaniline, o-methoxyaniline, m-methoxyaniline, p-methoxyaniline, o-ethoxyaniline, m-ethoxyaniline, p-ethoxyaniline, o-methylaniline, m-methylaniline, and p-methylaniline; and thiophene derivatives such as thiophene, 3-methylthiophene, 3-n-butylthiophene, 3-n-pentylthiophene, 3-n-hexylthiophene, 3-n-heptylthiophene, 3-n-octylthiophene, 3-n-nonylthiophene, 3-n-decylthiophene, 3-n-undecylthiophene, 3-n-dodecylthiophene, 3-methoxythiophene, 3-naphthoxythiophene, and 3,4-ethylenedioxythiophene, of which pyrrole, aniline, thiophene, and 3,4-ethylenedioxythiophene are preferred, and pyrrole is more preferred.

The conductive or reducing polymer microparticles contained in the undercoat paint for plating of the present invention are capable of reducing and adsorbing a catalytic metal such as palladium onto the conductive or reducing polymer microparticles when forming a metal plating film by electroless plating, and then forming a metal plating film starting from the conductive or reducing polymer microparticles to which the catalytic metal such as palladium is adsorbed.
Furthermore, when forming a plating undercoat layer by applying a plating undercoat to a substrate, either conductive polymer fine particles or reducing polymer fine particles can be used as the conductive or reducing polymer fine particles. When a plating undercoat layer is formed by applying a plating undercoat containing conductive polymer fine particles and a synthetic resin to a substrate, it is preferable to then carry out a dedoping treatment described below before reducing and adsorbing the catalytic metal.
In addition, when a metal plating film is formed on a plated product by electroless plating, catalytic metals such as palladium are reduced and adsorbed onto conductive or reducing polymer fine particles, so that the plated product becomes conductive polymer fine particles.

(Conductive polymer fine particles)
The conductive polymer fine particles are particles having electrical conductivity, specifically, fine particles having a conductivity of 0.01 S/cm or more.
The conductive polymer fine particles may be spherical fine particles, and the average particle size (measured by a laser diffraction/scattering method) is preferably 10 to 100 nm.

Conductive polymer particles can also be made of, for example, polypyrrole or polypyrrole derivatives that have conductive π-conjugated double bonds. They can also be synthesized from pyrrole monomers that have π-conjugated double bonds, but commercially available conductive polypyrrole particles can also be used.

(Reducible polymer fine particles)
As the reducing polymer fine particles, for example, polypyrrole or polypyrrole derivatives having π-conjugated double bonds and a conductivity of less than 0.01 S/cm can be used.
As the reducing polymer fine particles, polypyrrole fine particles having a conductivity of 0.005 S/cm or less are preferred.
The reducible polymer fine particles can be synthesized from a monomer having a π-conjugated double bond, but commercially available reducible polypyrrole fine particles can also be used.
The reducing polymer fine particles may be spherical fine particles, and the average particle size (measured by laser diffraction/scattering method) is preferably 10 to 100 nm.

<Synthetic resin>
Examples of synthetic resins that can be used in the present invention include polycarbonate resins, polyvinyl chloride resins, polystyrene resins, polymethyl methacrylate resins, polyester resins, polysulfone resins, polyphenylene oxide resins, polybutadiene resins, poly(N-vinylcarbazole) resins, hydrocarbon resins, ketone resins, phenoxy resins, polyamide resins, ethyl cellulose resins, vinyl acetate resins, ABS resins, polyurethane resins, melamine resins, acrylic resins, unsaturated polyester resins, alkyd resins, epoxy resins, and silicone resins.

It is also preferable that the synthetic resin in the undercoat layer (described below) contains at least 15% by mass of a synthetic resin with a glass transition temperature (Tg) of 30°C or lower. If the content is less than 15% by mass, cracks may occur in the undercoat layer after it is formed. Furthermore, there is a risk that the adhesion between the substrate with the coating layer and the metal plating film may decrease, and the stretchability of the substrate with the coating layer may decrease.

(inorganic filler)
Examples of inorganic fillers used in the present invention include silica particles, carbon black, and titanium oxide.

(solvent)
The undercoat for plating of the present invention may contain a solvent in addition to the conductive or reducing polymeric fine particles, synthetic resin, and inorganic filler.
Examples of solvents that can be contained in the primer coating include aliphatic esters such as butyl acetate, aromatic solvents such as toluene and xylene, ketones such as methyl ethyl ketone and cyclohexanone, cyclic saturated hydrocarbons such as cyclohexane, linear saturated hydrocarbons such as n-octane, linear saturated alcohols such as methanol, ethanol and n-octanol, aromatic esters such as methyl benzoate, aliphatic ethers such as diethyl ether, and mixtures thereof. When a dispersion liquid in which conductive or reducing polymer fine particles are dispersed in an organic solvent in advance is used, the organic solvent used in the dispersion liquid can be used as part or all of the solvent in the primer coating for plating.

Furthermore, the primer coating may contain dispersion stabilizers, thickeners, pigments, dyes, inorganic fillers, etc., depending on the application and the object to be coated.

(Various contents)
The content of the conductive or reducing polymer fine particles is, in terms of solid content, 5 to 19 parts by mass, preferably 7 to 11 parts by mass, of the conductive or reducing polymer fine particles per 100 parts by mass of the synthetic resin. If the content exceeds 19 parts by mass, peeling between the substrate with the coating layer and the metal plating film, as described below, becomes extremely likely, and good adhesion cannot be obtained. In addition, there is a risk of wire breakage when the substrate with the coating layer is stretched. If it is less than 5 parts by mass, there is a risk of significant deterioration in plating deposition properties. If the content of the conductive or reducing polymer fine particles is 7 to 11 parts by mass, the adhesion between the substrate with the coating layer and the metal plating film and the plating deposition properties of the substrate with the coating layer are superior. In addition, the substrate with the coating layer can be stretched without wire breakage even when stretched at a high ratio.
The content of the inorganic filler is, in terms of solid content, 11 to 45 parts by mass, preferably 16 to 27 parts by mass, per 100 parts by mass of synthetic resin. If the content exceeds 45 parts by mass, peeling between the substrate with the coating layer and the metal plating film, as described below, becomes extremely likely, and good adhesion cannot be obtained. In addition, there is a risk of wire breakage when the substrate with the coating layer is stretched. If the content is less than 11 parts by mass, there is a risk of significant deterioration in plating deposition properties. If the content is 16 to 27 parts by mass, the adhesion between the substrate with the coating layer and the metal plating film and the plating deposition properties of the substrate with the coating layer are superior. In addition, the substrate with the coating layer can be stretched without wire breakage even when stretched at a high ratio.

<Plating base coating layer>
The plating undercoat layer of the present invention can be obtained by printing a plating undercoat containing conductive or reducing polymer particles, a synthetic resin, and an inorganic filler onto a substrate.
Examples of printing methods include gravure printing, screen printing, flexographic printing, offset printing, dry offset printing, pad printing, and inkjet printing. For printing fine lines of 50 μm or less, gravure offset printing and screen printing are preferred, and screen printing is more preferred.
When the undercoat for plating is printed on a substrate, it is preferable that the undercoat be printed in a pattern with a line width of 50 μm or less.

<Base material>
The substrate is not particularly limited, but examples thereof include polycarbonate resin, polyester resin such as polyethylene terephthalate, acrylic resin such as polymethyl methacrylate, polypropylene resin, polystyrene resin, polyvinyl chloride resin, polyamide resin, polyimide resin, and glass, and may be appropriately selected when three-dimensional molding is performed.

The thickness of the plating base coating layer is not particularly limited, but is preferably in the range of 0.1 μm to 100 μm. If the thickness of the plating base coating layer is less than 0.1 μm, there is a risk that the adhesion between the substrate with the plating base coating layer (substrate with a coating layer) and the metal plating film will decrease, as will the plating deposition properties. If the thickness of the plating base coating layer exceeds 100 μm, there is a risk that the adhesion between the substrate with the coating layer and the metal plating film will decrease.

<Stretching of substrate with coating layer>
The substrate with a coating layer of the present invention can be stretched to form a three-dimensional shape. The substrate with a coating layer in the present invention is a substrate on which a plating primer coating layer made of the plating primer of the present invention is formed. Stretching in the present invention refers to stretching the substrate with a coating layer to a predetermined ratio.
The stretching ratio in the present invention is expressed as (thickness of substrate with coating layer before stretching/thickness of substrate with coating layer after stretching by vacuum forming)×100[%].
Specifically, the substrate with the coating layer is stretched by vacuum molding using a mold, and the thickness of the substrate with the coating layer after stretching is measured, and the stretching ratio can be calculated.
The three-dimensional molding in the present invention refers to three-dimensional molding (making the substrate with a coating layer into a three-dimensional shape) by vacuum molding, press molding, pressure molding or the like.
Furthermore, by using the undercoat coating for plating of the present invention, the substrate with the coating layer can be stretched without breaking even at a stretch ratio of 100% or more but less than 1000%.

<Method of manufacturing plated items>
The present invention provides a plated article having a metal plating film formed on the above-mentioned plating undercoat layer by electroless plating. When the plated article has a three-dimensional shape, the substrate with the coating layer may be three-dimensionally formed, and then plated.
In a method for producing a plated product, first, a substrate with a coating layer is treated with an alkaline dedoping treatment solution as needed. Then, the dedoped substrate is immersed in a catalyst solution for imparting a catalytic metal such as palladium chloride. Then, the substrate to which the catalytic metal such as palladium chloride has been imparted is immersed in a plating solution for depositing the metal, thereby obtaining a plated product.

(undoping)
The method for producing a plated product when using conductive polymer fine particles will be described below. Note that when using reducing polymer fine particles, the dedoping step is not required.
First, the substrate with the coating layer is treated with an alkaline dedoping solution. Note that "alkaline" refers to a value of 10 measured using a personal pH meter (manufactured by Yokogawa Electric Corporation). Specifically, a plating primer coating layer formed by applying a plating primer containing conductive polypyrrole microparticles and a synthetic resin to a substrate is dedoped from reducing to conductive. An example of the dedoping treatment is a method in which the substrate with the coating layer is immersed in a dedoping solution. For example, the treatment is carried out in an alkaline dedoping solution with a pH of 10 at a temperature of 20°C to 70°C, preferably 30°C to 40°C, for 1 minute to 30 minutes, preferably 3 minutes to less than 10 minutes.

(Catalyst Application)
The substrate with the dedoped coating layer is then immersed in a catalyst solution to impart a catalytic metal such as palladium chloride. The catalyst solution is a solution containing a precious metal (catalytic metal) that has catalytic activity for electroless plating. Examples of the catalytic metal include palladium, gold, platinum, and rhodium. These metals may be in the form of a single metal or a compound. Palladium compounds are preferred in terms of stability, including the catalytic metal, and palladium chloride is particularly preferred. A specific example of the catalyst solution is a 0.05 wt% palladium chloride-0.005 wt% hydrochloric acid aqueous solution (pH 3). The treatment temperature is 20 to 50°C, preferably 30 to 40°C, and the treatment time is 0.1 to 20 minutes, preferably 1 to 10 minutes. Through the above procedure, the reducing polypyrrole microparticles in the plating undercoat layer adsorb the catalytic metal, thereby becoming conductive polypyrrole microparticles.

(metal precipitation)
The substrate with the coating layer provided with a catalytic metal such as palladium chloride is then immersed in a plating solution for depositing the metal, resulting in a plated product with a metal plating film. The plating solution is not particularly limited as long as it is a plating solution typically used in electroless plating. That is, any metal usable for electroless plating, such as copper, gold, silver, or nickel, can be used, although copper is preferred. A specific example of an electroless copper plating solution is ATS Add Copper IW Bath (manufactured by Okuno Chemical Industries, Ltd.). The treatment temperature is 20 to 50°C, preferably 30 to 40°C, and the treatment time is 1 to 60 minutes, preferably 10 to 30 minutes. The resulting plated product is preferably aged for several hours or more, e.g., 2 hours or more, at a temperature lower than the Tg of the substrate used.

(resistance value)
The resistance value of the plated thin wire of the present invention was measured to check for breakage. The resistance value of the metal plating film is preferably less than 1.0× ¹⁰ Ω/cm, and more preferably less than 5.0× ¹⁰ Ω/cm. A resistance value of less than 1.0× ¹⁰ Ω/cm allows it to be used as an electrode member for sensors, etc., and a resistance value of less than 5.0× ¹⁰ Ω/cm provides good sensitivity as an electrode member for sensors, etc.

(peel strength)
In the plated product of the present invention, the peel strength between the substrate with the coating layer and the metal plating film is preferably 0.3 N/mm or more, more preferably 0.6 N/mm or more. If the peel strength is 0.3 N/mm or more, when fine line printing with a line width of 50 μm or less is performed, the adhesion between the substrate with the coating layer and the metal plating film is excellent, so that the substrate with the coating layer can be stretched without breaking.
Furthermore, if the peel strength is 0.6 N/mm or more, when fine line printing with a line width of 50 μm or less is performed, the adhesion between the substrate with the coating film layer and the metal plating film is better, and therefore the substrate with the coating film layer can be stretched without breakage.

The present invention will be explained based on examples. The reducing polymer microparticles, synthetic resin, and inorganic filler, which are components of the plating primer in Table 1, are as shown in the following examples. The numerical values indicating the composition of materials in Table 1 are in parts by mass.

Production Example 1: Preparation of plating primer A Anionic surfactant PEREX OT-P (Kao Corporation) 0.42 mmol, polyoxyethylene alkyl ether-based nonionic surfactant EMULGEN 409P (Kao Corporation) 2.1 mmol, toluene 10 mL, ion-exchanged water 100 mL were added and stirred until emulsified while maintaining the temperature at 20 ° C. 21.2 mmol of pyrrole monomer was added to the resulting emulsion and stirred for 1 hour, followed by addition of 6.0 mmol of ammonium persulfate and carrying out a polymerization reaction for 2 hours. After completion of the reaction, the organic phase was recovered and washed several times with ion-exchanged water to obtain reducing polypyrrole microparticles having reducing properties dispersed in toluene. The solid content of the reducing polypyrrole microparticles in the resulting toluene dispersion was 5.0%.
Separately, a synthetic resin: [VYLON 23CS: polyester-based (manufactured by Toyobo Co., Ltd.)] and an inorganic filler: [Black #5500: carbon black (manufactured by Tokai Carbon Co., Ltd.)] were mixed so that the solid content ratio was 45 parts by mass of inorganic filler per 100 parts by mass of synthetic resin, and after pre-stirring, the mixture was dispersed using a three-roll mill.
Next, the previously prepared dispersion containing synthetic resin and inorganic filler was mixed with the previously prepared dispersion of reducing polypyrrole microparticles so that the solids ratio was synthetic resin:conductive or reducing polymer microparticles:inorganic filler = 100:19:45, and the mixture was stirred and degassed to prepare primer coating A for plating.

Production Example 2: Preparation of primer coating B for plating A primer coating B for plating was prepared in the same manner as in Production Example 1, except that the solid content ratio of synthetic resin:conductive or reducing polymer fine particles:inorganic filler was 100:14:34.

Production Example 3: Preparation of primer coating C for plating A primer coating C for plating was prepared in the same manner as in Production Example 1, except that the solid content ratio of synthetic resin:conductive or reducing polymer fine particles:inorganic filler was 100:11:27.

Production Example 4: Preparation of primer coating D for plating A primer coating D for plating was prepared in the same manner as in Production Example 1, except that the solid content ratio of synthetic resin:conductive or reducing polymer fine particles:inorganic filler was 100:9:22.

Production Example 5: Preparation of primer coating E for plating A primer coating E for plating was prepared in the same manner as in Production Example 1, except that the solid content ratio of synthetic resin:conductive or reducing polymer fine particles:inorganic filler was 100:7:16.

Production Example 6: Preparation of primer coating F for plating A primer coating F for plating was prepared in the same manner as in Production Example 1, except that the solid content ratio of synthetic resin:conductive or reducing polymer fine particles:inorganic filler was 100:5:11.

Production Example 7: Preparation of primer coating G for plating A primer coating G for plating was prepared in the same manner as in Production Example 1, except that the solid content ratio of synthetic resin:conductive or reducing polymer fine particles:inorganic filler was 100:33:80.

Production Example 8: Preparation of primer coating H for plating A primer coating H for plating was prepared in the same manner as in Production Example 1, except that the solid content ratio of synthetic resin:conductive or reducing polymer fine particles:inorganic filler was 100:4:10.

The plating deposition properties and adhesion of Paints A to H obtained in the manufacturing examples were evaluated using the methods described below. The evaluation results are shown in Table 1. Furthermore, Paint H was rated "X" for plating deposition properties, so adhesion was not evaluated.

(Plating Deposition Properties)
Using a 0.5 mm thick PC film (Teijin Chemical Co., Ltd., Panlite PC1151: polycarbonate film), the above-prepared plating primer coatings A to H were printed using a screen printer in a fine line pattern with a thickness of 3.0 μm and an L/S of 50 μm/50 μm. The resulting substrate with the coating layer was then immersed in an electroless copper plating bath (ATS Add Copper IW) at 35°C for 20 minutes, yielding a plated product on which a metal plating film (copper plating film) with a line width of 50 μm was formed. The proportion of the metal plating film formed relative to the plating primer coating layer of the resulting plated product was visually confirmed to evaluate plating deposition properties.
・Plating was deposited on the entire surface of the plating base coating layer ... 〇 ・There were some parts of the plating base coating layer where plating was not deposited ... △
・There were areas where plating did not deposit in most of the plating base coating layer... ×

(Adhesion)
A 0.5 mm thick PC film (Teijin Chemical Co., Ltd., Panlite PC1151: polycarbonate film) was coated with the above-prepared plating primer coatings A to H to a thickness of 0.30 μm. The resulting substrate with the coating layer was then immersed in an electroless copper plating bath (ATS Add Copper IW) at 35 °C for 20 minutes, followed by electroplating to obtain a plated product with a 30 μm thick metal plating film (copper plating film). The resulting metal plating film was cut into a 5.0 x 12.0 cm rectangular test piece. A 5.0 mm wide cut was made in the test piece with a utility knife, and the stress (N/mm) when peeled off in a 180° direction at a pulling rate of 50 mm/min using a tensile tester (Imada Seisakusho: SV-52NA-5HH) was measured in accordance with JIS C 6471-1995.
In the present invention, a coating having a peel strength of 0.3 N/mm or more was used as a primer coating for plating, which has excellent adhesion.

Example 1
A 0.5 mm thick PC film (Panlite PC1151: polycarbonate film manufactured by Teijin Chemical Co., Ltd.) was used as the substrate, and the above-prepared plating primer coating A was printed with a fine line pattern of L/S = 50 μm/50 μm using a screen printing machine. The substrate was then heated and dried in a hot air oven at 100°C for 10 minutes, yielding a substrate with a coating layer having a plating primer coating layer thickness of 3.0 μm.

The substrate with the coating layer was then vacuum molded using various molds designed to achieve elongation rates of 140%, 250%, 330%, and 530%.

The formed substrate with the coating layer was then immersed in a 0.05% palladium chloride-0.005% hydrochloric acid aqueous solution at 35°C for 5 minutes, and then rinsed with cleaning water. The film was then immersed in an electroless copper plating bath, ATS Adcopper IW bath (manufactured by Okuno Chemical Industries Co., Ltd.), at 35°C for 20 minutes, rinsed with cleaning water, and then dried to obtain a plated product with a metal plating film.

Example 2
A plated product having a metal plating film formed thereon was obtained in the same manner as in Example 1, except that undercoat paint B for plating was used.

Example 3
A plated product having a metal plating film formed thereon was obtained in the same manner as in Example 1, except that the undercoat coating C for plating was used.

Example 4
A plated product having a metal plating film formed thereon was obtained in the same manner as in Example 1, except that undercoat paint D for plating was used.

Example 5
A plated product having a metal plating film formed thereon was obtained in the same manner as in Example 1, except that undercoat paint E for plating was used.

Example 6
A plated product having a metal plating film formed thereon was obtained in the same manner as in Example 1, except that undercoat paint F for plating was used.

(Comparative Example 1)
A plated product having a metal plating film formed thereon was obtained in the same manner as in Example 1, except that undercoat coating G for plating was used.

(Comparative Example 2)
The same procedure as in Example 1 was carried out except that undercoat paint H for plating was used, but no plating was deposited and no plated product was obtained.

The resistance values of the plated products obtained in Examples 1 to 6 and Comparative Example 1 were measured, and the results are shown in Table 2.
In Comparative Example 1, the substrate with the coating layer was split, resulting in a resistance value of 1.0 × ¹⁰ or more, and the resistance value was evaluated as "x." In Comparative Example 2, a plated product could not be obtained, and therefore the resistance value after stretching could not be measured, and therefore "-" was shown for "resistance value after stretching."

(resistance value)
The plated products obtained in Examples 1 to 6 and Comparative Example 1 were measured for resistance within 1.0 cm of the metal plating film using a digital multimeter (Custom Co., Ltd., CDM-2000D).
Resistance value less than 5.0 x 10 ¹ Ω/cm: Good. Resistance value 5.0 x 10 ¹ Ω/cm or more and less than 1.0 x 10 ⁶ Ω/cm: Fair.
Resistance value is 1.0 x 10 ⁶ Ω/cm or more... x

From the examples, it was confirmed that the undercoat for plating of the present invention enables printing of fine lines with a line width of 50 μm or less, and is excellent in plating deposition properties and adhesion after printing of fine lines with a line width of 50 μm or less.
Furthermore, the plating primer of the present invention provides a plating primer that does not cause the plating primer layer to break even when the substrate with the coating layer is stretched, since the resistance value of the plated product obtained by electroless plating after three-dimensional molding of the substrate with the coating layer is "less than 5.0 x 10 ¹ Ω/cm" or "5.0 x 10 ¹ Ω/cm or more but less than 1.0 x 10 ⁶ Ω/cm."
In addition, it has been possible to provide a method for producing a substrate with a coating layer and a plated product that do not break even when formed into a three-dimensional shape.

The plating primer of the present invention can be used for flat touch sensors, metal mesh, fine circuits, antennas, coils, etc. In addition, by combining it with three-dimensional molding, it can be used for curved touch sensors, three-dimensional circuits, etc.

Claims (3)

It is a base coating for plating to form three-dimensional plated objects,
The undercoat for plating contains conductive or reducing polymer particles, synthetic resin, and inorganic filler,
the polymer fine particles are polypyrrole fine particles,
the synthetic resin is a polyester-based resin,
the inorganic filler is made of any one of silica particles, carbon black, and titanium oxide;
the content of the conductive or reducing polymer fine particles is, in terms of solid content, 5 parts by mass or more and 19 parts by mass or less per 100 parts by mass of the synthetic resin;
The content of the inorganic filler is, in terms of solid content ratio, 11 parts by mass or more and 45 parts by mass or less with respect to 100 parts by mass of the synthetic resin ,
A primer coating for plating, capable of forming a plating primer coating layer having a line width of 50 μm or less . A plating undercoat layer made of the undercoat paint for plating according to claim 1 is formed on a substrate,
A substrate with a coating layer, characterized in that the line width of the plating undercoat layer is 50 μm or less . A method for producing a plated product, comprising three-dimensionally molding the substrate with the coating layer described in claim 2 and then subjecting it to electroless plating.