Laminate, cured product, and substrate

Abstract

This laminate comprises a first film and a resin layer which is formed from a curable resin composition and provided on one surface of the first film, wherein the curable resin composition contains: three or more kinds of (meth) acrylate resins; a photopolymerization initiator; a thermosetting resin; and a colorant, the (meth) acrylate resins include: a carboxyl group-containing resin (A) having a weight-average molecular weight of 2,000 or more and less than 8,000; a carboxyl group-containing resin (B) having a weight-average molecular weight of 8,000 to 14,000 inclusive; and a carboxyl group-free resin (C) having a weight-average molecular weight of 2,000 to 8,000 inclusive, the content of the carboxyl group-containing resin (B) in the curable resin composition is 30 mass% or more in terms of solid content with respect to 100 mass% of the total solid content of the (meth) acrylate resins, and in a cured product obtained by exposing the laminate to light to cure the resin layer and then completely curing with light and / or heat the resin layer peeled from the first film, the skewness Rsk (μm), the maximum peak height Rp (μm), and the maximum valley depth Rv (μm) of a surface in contact with the first film satisfy the following relational expressions: -3 ≤ Rsk ≤ -1; and 2 ≤ Rv / Rp ≤ 5.

Description

Laminates, cured products, and substrates

[0001] The present invention relates to laminates, cured products, and substrates.

[0002] Generally, in printed circuit boards used in electronic devices, a solder resist layer is formed on the substrate on which the circuit pattern is formed in order to prevent solder from adhering to areas other than where it is needed when mounting electronic components onto the printed circuit board.

[0003] In recent years, the surface of the solder resist layer has been roughened to improve its functionality. The advantages of roughening the surface of the solder resist layer include, for example, the following: (1) It can improve solder adhesion resistance and wiring concealment during solder flow. (2) By roughening the surface of the solder resist layer, the glossiness can be appropriately suppressed, resulting in good design aesthetics. Furthermore, (3) scratches are less visible on a roughened surface than on a glossy surface, which is also good for quality control. As a technique for roughening the surface of the solder resist layer, for example, Patent Document 1 describes that when forming a solder resist layer using a photosensitive dry film, the surface of the solder resist layer can be roughened by setting the surface roughness Ra of the support film to a range of 0.2 to 3 μm.

[0004] Japanese Patent Publication No. 2012-141605

[0005] However, the technology described in Patent Document 1 had room for improvement in terms of achieving both a good matte finish and characteristics such as resolution, scratch resistance, opacity, and insulation reliability.

[0006] The present invention aims to provide a laminate that can form a cured product that has a good matte finish and also exhibits good properties such as resolution, scratch resistance, opacity, and insulation reliability. Furthermore, the present invention aims to provide a cured product of the resin layer of the laminate, and a substrate equipped with the cured product.

[0007] In order to solve the above problems, the inventors have conducted extensive research and have found that a laminate comprising a first film and a resin layer formed from a curable resin composition of a specific composition, provided on one surface of the first film, can be made to have a good matte finish when the skewness Rsk (μm), maximum peak height Rp (μm), and maximum valley depth Rv (μm) of the surface of the cured resin layer that was in contact with the first film satisfy a specific range, and that the characteristics such as resolution, scratch resistance, opacity, and insulation reliability are also good.

[0008] This invention was completed based on these findings and includes the following broad embodiments of the invention.

[0009] [Item 1] A laminate comprising a first film and a resin layer formed from a curable resin composition provided on one surface of the first film, wherein the curable resin composition comprises a (meth)acrylate resin, a photopolymerization initiator, a thermosetting resin, and a colorant, wherein the (meth)acrylate resin comprises a carboxyl group-containing resin (A) with a weight-average molecular weight of 2000 or more and less than 8000, a carboxyl group-containing resin (B) with a weight-average molecular weight of 8000 or more and 14000 or less, and a carboxyl group-free resin (C) with a weight-average molecular weight of 2000 or more and 8000 or less, wherein the content of the carboxyl group-containing resin (B) in the curable resin composition is 30% by mass or more with respect to 100% by mass of the total solid content of the (meth)acrylate resin, [Item 2] A laminate obtained by exposing the laminate to light to cure the resin layer, and then further curing the resin layer peeled off from the first film with light and / or heat, wherein the skewness Rsk (μm), maximum peak height Rp (μm), and maximum valley depth Rv (μm) of the surface that was in contact with the first film satisfy the following relation: -3 ≤ Rsk ≤ -1 and 2 ≤ Rv / Rp ≤ 5. [Item 2] The laminate according to Item 1, wherein the skewness Rsk (μm) of the surface of the first film in contact with the resin layer satisfies the following relation: 1 ≤ Rsk ≤ 2.5. [Item 3] The laminate according to Item 1 or 2, wherein the mass ratio (A):(B):(C) of the solid content of the (meth)acrylate resin in the curable resin composition is 15 to 50:30 to 65:10 to 30. [Item 4] A cured product of the resin layer of the laminate according to any one of Items 1 to 3. [Item 5] A substrate comprising the cured product described in Item 4.

[0010] According to the present invention, it is possible to provide a laminate that can form a cured product that has a good matte finish and also exhibits good properties such as resolution, scratch resistance, opacity, and insulation reliability. Furthermore, the present invention can also provide a cured product of the resin layer of the laminate, and a substrate equipped with the cured product.

[0011] In this specification, the singular form (a, an, the, etc.) includes both singular and plural forms unless otherwise explicitly stated or the context clearly contradicts it. In this specification, "comprise" is a concept that also includes "consist essentially of" and "consist of."

[0012] In this specification, (meth)acrylate means at least one selected from the group consisting of acrylate (acrylic acid ester) and methacrylate (methacrylic acid ester). Furthermore, when a numerical range is expressed using "~" such as "A~B", unless otherwise specified, this means "A or greater and B or less".

[0013] 1. Laminate: The laminate comprises a first film of the present invention and a resin layer formed from a curable resin composition, provided on one surface of the first film.

[0014] In one embodiment, the laminate may comprise layers other than the first film and the resin layer. For example, a second film may be provided on the surface of the resin layer. The laminate of the present invention is preferably used as a dry film. Furthermore, the laminate of the present invention can preferably be used to form a solder resist layer on a printed circuit board, and more preferably a matte solder resist layer on a printed circuit board.

[0015] In the present invention, after exposing the laminate to the light to cure the resin layer, the resin layer peeled off the first film is further cured by light and / or heat to obtain a cured product in which the skewness Rsk (μm), maximum peak height Rp (μm), and maximum valley depth Rv (μm) of the surface that was in contact with the first film satisfy the following relationship: -3 ≤ Rsk ≤ -1 and 2 ≤ Rv / Rp ≤ 5. Conventionally, surface roughening has been performed to impart a matte feel to cured products, but simply defining the range of surface roughness Ra makes it difficult to stably achieve both a matte feel and the characteristics of the cured resin layer (resolution, scratch resistance, opacity, insulation reliability, etc.). In the present invention, it has been found that if the surface shape satisfies the above formula for skewness Rsk, maximum peak height Rp, and maximum valley depth Rv, rather than surface roughness Ra, a good matte feel can be obtained, and characteristics such as resolution, scratch resistance, opacity, and insulation reliability are also good. The reason for this is not clear, but it can be inferred as follows: By satisfying the above relationship, sharp valleys are formed on the surface that was in contact with the first film, so the edges of the pattern are less likely to become uneven, making pattern formation easier and resulting in good properties. In addition, gentle peaks are formed on the surface that was in contact with the first film, so it is inferred that scratch resistance will also be good. However, this is merely speculation and may not be the case.

[0016] In this specification, the skewness Rsk, maximum peak height Rp, and maximum valley depth Rv of the cured resin layer of the laminate described above can be measured as follows. First, the resin layer of the laminate is bonded to the copper-clad laminate using a vacuum laminator so that it is in contact with the copper-clad laminate. Then, exposure is measured at 23.5 ± 0.5°C using a high-pressure mercury lamp at an exposure dose of 300 mJ / cm². ２ After exposure, the first film is peeled off. Then, 1% by mass of Na at 30°C ２ CO ３ The film is developed using an aqueous solution at a spray pressure of 0.2 MPa, and then washed with deionized water at 25°C at a spray pressure of 0.1 MPa. Afterwards, exposure is applied using a high-pressure mercury lamp at an exposure dose of 1000 mJ / cm². ２After exposure, the resin layer is cured by heat curing in a hot air circulating box-type drying oven at 160°C for 60 minutes. Next, the skewness Rsk, maximum peak height Rp, and maximum valley depth Rv are measured in accordance with JIS B 0601 using a shape measuring laser microscope (VX-100) manufactured by Keyence Corporation. An observation image is acquired using the observation application (VK-H1XV) in shape measurement mode with a 100x objective lens. Then, the values ​​of Rsk, Rp, and Rv are measured at five locations within a 50 μm × 50 μm area using the analysis application (VK-H1XA), and their averages are defined as "skewness Rsk," "maximum peak height Rp," and "maximum valley depth Rv" in this invention.

[0017] The skewness Rsk in the above description is -3 μm to -1 μm, and preferably -2.5 μm to -1.1 μm. Furthermore, the ratio of the maximum peak height to the maximum valley depth (Rv / Rp) in the above description is 2 to 5, and preferably 2.2 to 4.1. By being within the above range, a good matte finish is obtained, and characteristics such as resolution, scratch resistance, opacity, and insulation reliability are also good.

[0018] In one embodiment, after exposing the laminate of the present invention to curing the resin layer, the resin layer peeled off from the first film is further cured by light and / or heat to obtain a cured product, in which the 60° gloss of the surface that was in contact with the first film is preferably 5 to 30, and more preferably 19 to 26, from the viewpoint of matte finish.

[0019] In this specification, the glossiness of the cured resin layer of the laminate can be measured as follows. First, the resin layer of the laminate is bonded to the copper-clad laminate using a vacuum laminator so that it is in contact with the copper-clad laminate. Then, exposure is measured at 23.5 ± 0.5°C using a high-pressure mercury lamp at an exposure dose of 300 mJ / cm². ２ After exposure, the first film is peeled off. Then, 1% by mass of Na at 30°C ２ CO ３The film is developed using an aqueous solution at a spray pressure of 0.2 MPa, and then washed with deionized water at 25°C at a spray pressure of 0.1 MPa. Afterwards, exposure is applied using a high-pressure mercury lamp at an exposure dose of 1000 mJ / cm². ２ After exposure, the resin layer is cured by heat curing in a hot air circulating box-type drying oven at 160°C for 60 minutes. Next, the glossiness at 60° is measured in accordance with JIS Z 8741-1997. First, as a premise, on a surface with a refractive index of 1.567, the intensity of light with a reflectivity of 10% at an incident angle of 60° is set to glossiness 100, and the intensity of light with a reflectivity of 0% is set to 0. Thus, a value of 1 / 100th of the intensity of light with a reflectivity of 10% corresponds to glossiness 1. The intensity of light on the surface of the cured film provided on the substrate is measured using a reflectometer with geometric conditions at an incident angle of 60°. Then, the glossiness is calculated by dividing the obtained light intensity by the value of 1 / 100th of the intensity of light with a reflectivity of 10% as described above. For a simpler approach, the glossiness of the surface of a cured material can be measured using a digital angle-bending gloss meter (Micro-Tri-Gloss, manufactured by BYK Gardener). Note that "60° glossiness (Gs(60°))" is the glossiness value when the incident angle is 60° and the receiving angle is 60°.

[0020] The following describes each element that constitutes the laminate of the present invention.

[0021] <First Film> The laminate of the present invention comprises a first film. The first film preferably serves as a support for the resin layer described later, and when the resin layer provided on one side of the first film is laminated so as to be in contact with the substrate, it is at least adhered to the resin layer. In the present invention, it is preferable that the first film is peeled off from the resin layer in a process after lamination of the substrate and the resin layer.

[0022] As the first film, films made of thermoplastic resins such as polyester films (e.g., polyethylene terephthalate, polyethylene naphthalate), polyimide films, polyamide-imide films, polypropylene films, and polystyrene films can be suitably used. Among these, polyester films are preferred from the viewpoint of heat resistance, mechanical strength, and handling, and polyethylene terephthalate films are particularly preferred. A laminate of the above films can also be used as the first film. The above film may be a film stretched in one or two axes from the viewpoint of improving mechanical strength.

[0023] Furthermore, the first film may be one in which a filler is added to the resin during film formation (mixing treatment), a matte coating (coating treatment) is applied, the film surface is subjected to a blast treatment such as sandblasting, or a hairline finish or chemical etching treatment is applied. In the first film that has been matte coated, the coating agent used for the coating layer may include, for example, a resin commonly used as a coating agent such as acrylic melamine resin or acrylic resin, along with a filler, a solvent, etc.

[0024] The skewness Rsk (μm) of the surface of the first film in contact with the resin layer preferably satisfies the following relationship: 1 ≤ Rsk ≤ 2.5. The skewness Rsk is preferably 1 μm or more and 2.5 μm or less, and more preferably 1.3 μm or more and 2 μm or less. Having this range makes it easy to adjust the skewness Rsk, maximum peak height Rp, and maximum valley depth Rv of the cured resin layer of the laminate to the above range. The reason for this is not clear, but it can be inferred as follows: It is presumed that by using a first film with sharp peaks on its surface, it is possible to give the resin layer side good surface roughness and shape. Also, it is presumed that because the sharp peaks are in contact with the resin layer, light scattering during exposure is reduced and the reaction proceeds uniformly, so that there are no areas where photocuring is insufficient and a cured product with a stable uneven shape can be obtained. However, this is merely in the realm of speculation and is not limited to this.

[0025] There are no particular limitations on the method for setting the skewness Rsk of the surface of the first film in contact with the resin layer to 1 μm or more and 2.5 μm or less, but examples include adjusting the average particle size and content of the added filler, and the film thickness of the first film and the coating layer. Alternatively, commercially available films with a skewness Rsk of 1 μm or more and 2.5 μm or less may be used.

[0026] In this specification, the skewness Rsk of the surface of the first film in contact with the resin layer can be measured in accordance with JIS B 0601 using a shape measuring laser microscope (VX-100) manufactured by Keyence Corporation. An observation image is acquired using the observation application (VK-H1XV) in shape measurement mode with a 100x objective lens. Then, the Rsk values ​​of five locations within a 50 μm × 50 μm area are measured using the analysis application (VK-H1XA), and the average of these values ​​is defined as the "skewness Rsk" in this invention.

[0027] The thickness of the first film is not particularly limited, but considering flexibility and bendability, it is usually about 1 to 1000 μm, preferably 5 to 500 μm, more preferably 10 to 200 μm, and especially preferably 20 to 200 μm.

[0028] <Resin Layer> The laminate of the present invention comprises a resin layer provided on one side of the first film. The resin layer is formed from a curable resin composition. Here, the resin layer is formed by applying and drying the curable resin composition. Preferably, the resin layer forms a cured layer by a curing process, and particularly preferably a solder resist layer.

[0029] The components of the curable resin composition are described below.

[0030] (Meth)acrylate resin) The curable resin composition used in the present invention contains a (meth)acrylate resin. A (meth)acrylate resin is a polymer compound having one or more (preferably two or more) (meth)acrylate groups in one molecule.

[0031] The curable resin composition used in the present invention contains the following resins (A) to (C) as (meth)acrylate resins. The following resins (A) to (C) may be used individually or in combination of two or more. • (A) A carboxyl group-containing resin with a weight-average molecular weight of 2000 or more and less than 8000 (hereinafter also referred to as resin (A)). • (B) A carboxyl group-containing resin with a weight-average molecular weight of 8000 or more and 14000 or less (hereinafter also referred to as resin (B)). • (C) A carboxyl group-free resin with a weight-average molecular weight of 2000 or more and 8000 or less (hereinafter also referred to as resin (C)).

[0032] The above resin (A) is a polymer compound having one or more (preferably two or more) (meth)acrylate groups and one or more (preferably two or more) carboxyl groups per molecule. The weight-average molecular weight is 2000 or more and less than 8000, preferably 2100 or more and 5000 or less, and more preferably 2300 or more and 3000 or less. The weight-average molecular weight can be measured using gel permeation chromatography (GPC) with standard polystyrene as the standard substance.

[0033] The above resin (B) is a polymer compound having one or more (preferably two or more) (meth)acrylate groups and one or more (preferably two or more) carboxyl groups per molecule. The weight average molecular weight is not less than 8000 and not more than 14000, preferably not less than 8500 and not more than 12000, and more preferably not less than 9000 and not more than 11000. The weight average molecular weight can be measured by gel permeation chromatography (GPC) using standard polystyrene as a standard substance.

[0034] As the above resins (A) and (B), for example, oligomers or polymers listed below are preferred, but the resins are not limited thereto and can be used.

[0035] (1) A carboxyl group-containing resin obtained by reacting a difunctional or higher polyfunctional epoxy resin with (meth)acrylic acid, and adding a dibasic acid anhydride (e.g., phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, etc.) to a hydroxyl group present in a side chain.

[0036] (2) A carboxyl group-containing resin obtained by further epoxidizing the hydroxyl groups of a difunctional epoxy resin with epichlorohydrin to obtain a polyfunctional epoxy resin, reacting the polyfunctional epoxy resin with (meth)acrylic acid, and adding a dibasic acid anhydride to the resulting hydroxyl groups.

[0037] (3) A carboxyl group-containing resin obtained by reacting an epoxy compound having two or more epoxy groups per molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group per molecule and an unsaturated group-containing monocarboxylic acid such as (meth)acrylic acid, and then reacting a polybasic acid anhydride (e.g., maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, adipic anhydride, etc.) with the alcoholic hydroxyl groups of the obtained reaction product.

[0038] (4) A carboxyl group-containing resin obtained by reacting a compound having two or more phenolic hydroxyl groups in one molecule (e.g., bisphenol A, bisphenol F, bisphenol S, novolac-type phenolic resins, poly-p-hydroxystyrene, condensates of naphthol and aldehydes, condensates of dihydroxynaphthalene and aldehydes, etc.) with an alkylene oxide (e.g., ethylene oxide, propylene oxide, etc.), reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid such as (meth)acrylic acid, and then reacting the obtained reaction product with a polybasic acid anhydride.

[0039] (5) A carboxyl group-containing resin obtained by reacting a compound having two or more phenolic hydroxyl groups in one molecule with a cyclic carbonate compound (e.g., ethylene carbonate, propylene carbonate, etc.), reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the obtained reaction product with a polybasic acid anhydride.

[0040] (6) A carboxyl group-containing resin obtained by adding a compound having a cyclic ether group and a (meth)acryloyl group in one molecule to a terminal carboxyl group-containing urethane resin, wherein the terminal carboxyl group-containing urethane resin is obtained by reacting an acid anhydride with the terminal of a urethane resin formed by polyaddition reaction of a diisocyanate compound (e.g., aliphatic diisocyanate, branched aliphatic diisocyanate, alicyclic diisocyanate, aromatic diisocyanate, etc.) and a polyol compound (e.g., polycarbonate-based polyol, polyether-based polyol, polyester-based polyol, polyolefin-based polyol, acrylic polyol, bisphenol A-based alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group, etc.).

[0041] (7) A carboxyl group-containing resin with terminal (meth)acrylation obtained by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups in a molecule such as hydroxyalkyl (meth)acrylate during the synthesis of a carboxyl group-containing urethane resin via polyaddition reaction of a diisocyanate, a carboxyl group-containing dialcohol compound (e.g., dimethylolpropionic acid, dimethylolbutyric acid, etc.) and a diol compound.

[0042] (8) A carboxyl group-containing resin obtained by adding a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate, to the synthesis of a carboxyl group-containing urethane resin by polyaddition reaction of diisocyanate, a carboxyl group-containing dialcohol compound, and a diol compound, thereby terminating (meth)acrylically formed carboxyl group-containing resin.

[0043] (9) A carboxyl group-containing resin obtained by copolymerizing an unsaturated carboxylic acid such as (meth)acrylic acid with an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth)acrylate, or isobutylene, to which a compound having a cyclic ether group and a (meth)acryloyl group in one molecule is added.

[0044] (10) A carboxyl group-containing polyester resin obtained by reacting a polyfunctional oxetane resin with a dicarboxylic acid (e.g., adipic acid, phthalic acid, hexahydrophthalic acid, etc.), adding a dibasic acid anhydride to the resulting primary hydroxyl group, and then adding a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule (e.g., glycidyl (meth)acrylate, α-methylglycidyl (meth)acrylate, etc.) to the carboxyl group-containing polyester resin.

[0045] (11) A carboxyl group-containing photosensitive resin obtained by adding a compound having a cyclic ether group and a (meth)acryloyl group in one molecule to any of the carboxyl group-containing photosensitive resins described in (1) to (5), (7), (8), and (10) above.

[0046] Of the carboxyl group-containing resins exemplified as (1) to (11) above, resin (A) and (B) are preferred from the viewpoint of improving insulation reliability, as is (4).

[0047] The acid value of resins (A) and (B) is preferably 20 to 200 mg KOH / g, more preferably 40 to 150 mg KOH / g, and even more preferably 45 to 120 mg KOH / g, from the viewpoint of improving the alkali developability of the curable resin composition.

[0048] The resin (C) is a polymer compound having one or more (preferably two or more) (meth)acrylate groups per molecule and no carboxyl groups. The weight-average molecular weight is 2000 to 8000, preferably 3000 to 7500, and more preferably 4000 to 7000. The weight-average molecular weight can be measured using gel permeation chromatography (GPC) with standard polystyrene as the standard substance.

[0049] Examples of the above resin (C) include (meth)acrylate-modified phenolic resins such as phenol novolac (meth)acrylate, cresol novolac (meth)acrylate, and bisphenol-type (meth)acrylate; epoxy (meth)acrylates such as phenol novolac epoxy (meth)acrylate, cresol novolac epoxy (meth)acrylate, and bisphenol-type epoxy (meth)acrylate; urethane (meth)acrylate, epoxy urethane (meth)acrylate, and polybutadiene urethane (meth)acrylate; polyether (meth)acrylates such as polyoxyethylene (meth)acrylate and polyoxypropylene (meth)acrylate; polyester (meth)acrylate; polybutadiene-modified (meth)acrylate; and polycarbonate methacrylate. These may be used individually or in combination of two or more types.

[0050] In one embodiment, when resins (A) and (B) are carboxyl group-containing resins as described in (4) above, resin (C) is preferably a (meth)acrylate-modified phenol resin from the viewpoint of compatibility and the properties of the resin layer.

[0051] From the viewpoint of improving coating hardness, the content of (meth)acrylate resin in the curable resin composition is preferably 30 to 45% by mass, and more preferably 35 to 43% by mass, based on 100% by mass of the solid content of the curable resin composition.

[0052] In the curable resin composition, the content of resin (A) is preferably 15 to 50% by mass, and more preferably 20 to 40% by mass, based on the total solid content of the (meth)acrylate resin, from the viewpoint of improving resolution and scratch resistance.

[0053] In the curable resin composition, the content of resin (B) is preferably 30% by mass or more, and more preferably 30 to 65% by mass, and more preferably 40 to 60% by mass, based on the total solid content of the (meth)acrylate resin, with respect to 100% by mass of the solid content.

[0054] In the curable resin composition, the content of resin (C) is preferably 10 to 30% by mass, and more preferably 15 to 25% by mass, in terms of solid content, relative to 100% by mass of the total solid content of the (meth)acrylate resin, from the viewpoint of improving resolution and insulation reliability.

[0055] In a curable resin composition, the mass ratio (A):(B):(C) of the solid content of resin (A), resin (B), and resin (C) is preferably 15-50:30-65:10-30, and more preferably 20-40:40-60:15-25, from the viewpoint of improving resolution, scratch resistance, and insulation reliability.

[0056] (Photopolymerization initiator) The curable resin composition used in the present invention contains a photopolymerization initiator. Known and commonly used photopolymerization initiators can be used in the curable resin composition without particular limitations.

[0057] Examples of photopolymerization initiators include α-aminoacetophenone-based photopolymerization initiators such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, N,N-dimethylaminoacetophenone, 1-hydroxycyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2 Hydroxyacetophenone-based photopolymerization initiators such as -hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, and bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide. Fin oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenyl Acylphosphine oxide-based photopolymerization initiators such as luchosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinate methyl ester, 2-methylbenzoyl diphenylphosphine oxide, pivaloylphenylphosphinate isopropyl ester, and 2,4,6-trimethylbenzoyl diphenylphosphine oxide; benzoin-based photopolymerization initiators such as benzoin, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and benzoin n-butyl ether;Benzoin alkyl ether photopolymerization initiators; Benzophenone-based photopolymerization initiators such as benzophenone, p-methylbenzophenone, Michla's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone; Acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2- Acetophenone-based photopolymerization initiators such as morpholino-1-propanone; thioxanthone-based photopolymerization initiators such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2- Anthraquinone-based photopolymerization initiators such as aminoanthraquinone; ketal-based photopolymerization initiators such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzoic acid ester-based photopolymerization initiators such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, and p-dimethylbenzoate ethyl ester; 2-(O-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]ethanone 1- Oxime ester-based photopolymerization initiators such as (O-acetyloxime); titanocene-based photopolymerization initiators such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl)titanium, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl)titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1H-pyrrole-1-yl)ethyl)phenyl]titanium;Examples include the following. Among these, acylphosphine oxide-based photopolymerization initiators, titanocene-based photopolymerization initiators, α-aminoacetophenone-based photopolymerization initiators, anthraquinone-based photopolymerization initiators, and oxime-based photopolymerization initiators are preferred. These may be used individually or in combination of two or more.

[0058] Commercially available acylphosphine oxide photopolymerization initiators include TPO from Kusumoto Chemicals, Inc. and Omnirad 819 from IGM Resins. Commercially available titanocene photopolymerization initiators include, for example, JMT-784 from Yueyang Kimoutain Sci-tech Co., Ltd. Commercially available α-aminoacetophenone photopolymerization initiators include Omnirad 907, 369, 369E, and 379 from IGM Resins. Commercially available anthraquinone photopolymerization initiators include 2-ethylanthraquinone from Tokyo Chemical Industry Co., Ltd. Commercially available oxime ester-based photopolymerization initiators include Irgacure OXE01 and OXE02 from BASF Japan Ltd., N-1919 from ADEKA Corporation, ADEKA Arcles NCI-831 and NCI-831E, and TR-PBG-304 from Changzhou Strong Electronic New Materials Co., Ltd.

[0059] From the viewpoint of photocurability and the physical properties of the cured product, the content of the photopolymerization initiator in the curable resin composition is preferably 1 to 5% by mass, and more preferably 2.5 to 3.5% by mass, based on the solid content of 100% by mass of the solid content of the curable resin composition.

[0060] (Thermosetting Resin) The curable resin composition used in the present invention includes a thermosetting resin. Known and commonly used thermosetting resins can be used, such as isocyanate compounds, blocked isocyanate compounds, amino resins, maleimide compounds, benzoxazine resins, carbodiimide resins, cyclocarbonate compounds, epoxy resins, oxetane compounds, episulfide resins, etc. Among these, epoxy resins are preferred. The thermosetting resin may be used alone or in combination of two or more types.

[0061] As the epoxy resin mentioned above, known and conventional compounds having one or more epoxy groups can be used, and among them, compounds having two or more epoxy groups are preferred. Examples include monoepoxy compounds such as butyl glycidyl ether, phenyl glycidyl ether, and glycidyl (meth)acrylate; bisphenol A type epoxy resin, bisphenol S type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, trisphenolmethane type epoxy resin, alicyclic epoxy resin, trimethylolpropane polyglycidyl ether, phenyl-1,3-diglycidyl ether, biphenyl-4,4'-diglycidyl ether, 1,6-hexanediol diglycidyl ether, ethylene glycol or propylene glycol diglycidyl ether, sorbitol polyglycidyl ether, tris(2,3-epoxypropyl) isocyanurate, and triglycidyltris(2-hydroxyethyl) isocyanurate, which are compounds having two or more epoxy groups in one molecule.

[0062] Compounds having two or more epoxy groups include, specifically, jER® 828, jER 834, jER 1001, jER 1004 from Mitsubishi Chemical Corporation, EPICLON® 840, EPICLON 850, EPICLON 1050, EPICLON 2055 from DIC Corporation, Epotote YD-011, YD-013, YD-127, YD-128 from Nippon Steel Chemical & Material Corporation, and D.E.R. 317, D.E.R. 331, D.E.R. 661, D.E.R. Bisphenol A type epoxy resins such as 664, Sumi-Epoxy ESA-011, ESA-014, ELA-115, ELA-128 manufactured by Sumitomo Chemical Co., Ltd., A.E.R. 330, A.E.R. 331, A.E.R. 661, A.E.R. 664 manufactured by Asahi Kasei Corporation; jERYL903 manufactured by Mitsubishi Chemical Corporation, EPICLON152, EPICLON165 manufactured by DIC Corporation, Epotote YDB-400, YDB-500 manufactured by Nippon Steel Chemical & Material Co., Ltd., D.E.R. 542 manufactured by Dow Chemical Japan Ltd., Sumi-Epoxy ESB-400, ESB-700 manufactured by Sumitomo Chemical Co., Ltd., A.E.R. 711, A.E. Brominated epoxy resins such as R. 714; jER152, jER154 from Mitsubishi Chemical Corporation; D.E.N. 431, D.E.N. 438 from Dow Chemical Japan Ltd.; EPICLONN-730, EPICLONN-770, EPICLONN-865 from DIC Corporation; Epotote YDCN-701, YDCN-704 from Nippon Steel Chemical & Material Corporation; EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306, NC-3000, NC-3000H from Nippon Kayaku Co., Ltd.; Sumi-Epoxy ESCN-195X, ESCN-220 from Sumitomo Chemical Co., Ltd.; A.E.R. from Asahi Kasei Corporation. Novolac-type epoxy resins such as ECN-235, ECN-299, YDCN-700-2, YDCN-700-3, YDCN-700-5, YDCN-700-7, YDCN-700-10, YDCN-704, YDCN-704A from Nippon Steel Chemical & Material Co., Ltd., and EPICLONN-680, N-690, N-695, N-870 from DIC Corporation;Bisphenol F type epoxy resins such as EPICLON830 from DIC Corporation, jER807 from Mitsubishi Chemical Corporation, and Epotote YDF-170, YDF-175, and YDF-2004 from Nippon Steel Chemical & Material Corporation; hydrogenated bisphenol A type epoxy resins such as Epotote ST-2004, ST-2007, and ST-3000 from Nippon Steel Chemical & Material Corporation; jER604 from Mitsubishi Chemical Corporation and Epotote YH-434 from Nippon Steel Chemical & Material Corporation; glycidylamine type epoxy resins such as Sumi-Epoxy ELM-120 from Sumitomo Chemical Co., Ltd.; hydantoin type epoxy resins; alicyclic epoxy resins such as Celoxide 2021 from Daicel Corporation; YL-933 from Mitsubishi Chemical Corporation and T.E.N. from Dow Chemical Japan Ltd. Trihydroxyphenylmethane type epoxy resins such as EPPN-501 and EPPN-502; bixylenol type or biphenol type epoxy resins or mixtures thereof, such as YL-6056, YX-4000, and YL-6121 from Mitsubishi Chemical Corporation; bisphenol S type epoxy resins such as EBPS-200 from Nippon Kayaku Co., Ltd., EPX-30 from ADEKA Corporation, and EXA-1514 from DIC Corporation; bisphenol A novolac type epoxy resins such as jER157S from Mitsubishi Chemical Corporation; tetraphenyloleethane type epoxy resins such as jERYL-931 from Mitsubishi Chemical Corporation; heterocyclic epoxy resins such as TEPIC from Nissan Chemical Corporation; and diglycidyl phthalate resins such as Brembo DGT from NOF Corporation. Tetraglycidyl xylenoylethane resins such as ZX-1063 manufactured by Nippon Steel Chemical & Material Co., Ltd.; Naphthalene group-containing epoxy resins such as ESN-190 and ESN-360 manufactured by Nippon Steel Chemical & Material Co., Ltd., and HP-4032, EXA-4750, and EXA-4700 manufactured by DIC Corporation; epoxy resins having a dicyclopentadiene skeleton such as HP-7200, HP-7200L, and HP-7200H manufactured by DIC Corporation; Glycidyl methacrylate copolymer epoxy resins such as CP-50S and CP-50M manufactured by NOF Corporation; further copolymer epoxy resins of cyclohexylmaleimide and glycidyl methacrylate; CTBN-modified epoxy resins (e.g., YR-102 and YR-450 manufactured by Nippon Steel Chemical & Material Co., Ltd.);Examples include trisphenolmethane-type epoxy resins, but are not limited to these.

[0063] From the viewpoint of ensuring the strength of the cured coating film, the content of thermosetting resin in the curable resin composition is preferably 10 to 30% by mass, and more preferably 12 to 20% by mass, based on the solid content of 100% by mass of the curable resin composition.

[0064] (Coloring agent) The curable resin composition used in the present invention contains a coloring agent. Known coloring agents such as red, blue, green, yellow, and black can be used as the coloring agent, and any of pigments, dyes, or pigments may be used, but from the viewpoint of reducing environmental impact and minimizing the impact on the human body, a halogen-free coloring agent is preferred.

[0065] Red colorants include monoazo, disazo, azolake, benzimidazolon, perylene, diketopyrrolopyrrole, condensed azo, anthraquinone, and quinacridone, and specifically those that are assigned a color index (C.I.; issued by The Society of Dyersan and Colorists) number, as follows: Examples of monoazo-based red colorants include Pigment Red 1, 2, 3, 4, 5, 6, 8, 9, 12, 14, 15, 16, 17, 21, 22, 23, 31, 32, 112, 114, 146, 147, 151, 170, 184, 187, 188, 193, 210, 245, 253, 258, 266, 267, 268, and 269. Examples of disazo-based red colorants include Pigment Red 37, 38, and 41. Examples of monoazolake-based red colorants include Pigment Red 48:1, 48:2, 48:3, 48:4, 49:1, 49:2, 50:1, 52:1, 52:2, 53:1, 53:2, 57:1, 58:4, 63:1, 63:2, 64:1, 68, etc. Examples of benzimidazolone-based red colorants include Pigment Red 171, 175, 176, 185, 208, etc. Examples of perylene-based red colorants include Solvent Red 135, 179, Pigment Red 123, 149, 166, 178, 179, 190, 194, 224, etc. Examples of diketopyrrolopyrrole-based red colorants include Pigment Red 254, 255, 264, 270, and 272. Examples of condensed azo-based red colorants include Pigment Red 220, 144, 166, 214, 220, 221, and 242. Examples of anthraquinone-based red colorants include Pigment Red 168, 177, and 216, and Solvent Red 52, 149, 150, and 207. Examples of quinacridone-based red colorants include Pigment Red 122, 202, 206, 207, and 209.

[0066] Blue colorants include phthalocyanine-based and anthraquinone-based compounds, while pigment-based compounds include those classified as pigments, such as Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, and 60. Dyes such as Solvent Blue 35, 63, 67, 68, 70, 83, 87, 94, 97, 122, and 136 can also be used. In addition to the above, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

[0067] Examples of yellow colorants include monoazo, disazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone. For example, anthraquinone yellow colorants include Solvent Yellow 163, Pigment Yellow 24, 108, 193, 147, 199, and 202. Isoindolinone yellow colorants include Pigment Yellow 110, 109, 139, 179, and 185. Condensed azo yellow colorants include Pigment Yellow 93, 94, 95, 128, 155, 166, and 180. Examples of benzimidazolone-based yellow colorants include Pigment Yellow 120, 151, 154, 156, 175, and 181. Examples of monoazo-based yellow colorants include Pigment Yellow 1, 2, 3, 4, 5, 6, 9, 10, 12, 61, 62, 62:1, 65, 73, 74, 75, 97, 100, 104, 105, 111, 116, 167, 168, 169, 182, and 183. Furthermore, examples of disazo-based yellow colorants include Pigment Yellow 12, 13, 14, 16, 17, 55, 63, 81, 83, 87, 126, 127, 152, 170, 172, 174, 176, 188, and 198.

[0068] Examples of black colorants include carbon black, Pigment Black 1, 6, 7, 8, 9, 10, 11, 12, 13, 18, 20, 25, 26, 28, 29, 30, 31, and 32.

[0069] Other colorants such as purple, orange, and brown may be added. Specifically, examples include Pigment Violet 19, 23, 29, 32, 36, 38, 42, Solvent Violet 13, 36, C. I. Pigment Orange 1, 5, 13, 14, 16, 17, 24, 34, 36, 38, 40, 43, 46, 49, 51, 61, 63, 64, 71, 73, Pigment Brown 23, 25, etc.

[0070] The content of the colorant in the curable resin composition is not particularly limited, but from the viewpoint of improving opacity, it is preferably 0.1 to 2.0% by mass, and more preferably 0.5 to 1.5% by mass, based on the solid content of 100% by mass of the curable resin composition.

[0071] In addition to the above, the curable resin composition may contain the following components, as long as they do not hinder the effects of the present invention.

[0072] (Meth)acrylate monomers: Curable resin compositions may contain (meth)acrylate monomers. By including (meth)acrylate monomers, photocurability and coating film hardness can be improved.

[0073] Examples of (meth)acrylate monomers include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate; aryl (meth)acrylates such as phenyl (meth)acrylate; hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; ethylene glycol; and methoxytetraethylene glycol. , di(meth)acrylates of glycols such as polyethylene glycol and propylene glycol; (meth)acrylamides such as N,N-dimethyl(meth)acrylamide, N-methylol(meth)acrylamide, and N,N-dimethylaminopropyl(meth)acrylamide; aminoalkyl(meth)acrylates such as N,N-dimethylaminoethyl(meth)acrylate and N,N-dimethylaminopropyl(meth)acrylate; hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, tris-hydroxy Polyhydric (meth)acrylates derived from polyhydric alcohols such as ethyl isocyanurate or their ethylene oxide adducts, propylene oxide adducts, or ε-caprolactone adducts; polyhydric (meth)acrylates such as phenoxyacrylate, bisphenol A diacrylate, and ethylene oxide adducts or propylene oxide adducts of these phenols; glycidyl ethers such as glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate. Polyvalent (meth)acrylates derived from methyl acrylates; not limited to the above, (meth)acrylates obtained by directly (meth)acrylateing polyols such as polyether polyols, polycarbonate diols, hydroxyl-terminated polybutadienes, and polyester polyols, or by urethane (meth)acrylateing via diisocyanate; melamine (meth)acrylate; polyester (meth)acrylate, polyether (meth)acrylate, urethane (meth)acrylate, carbonate (meth)acrylate, epoxy (meth)acrylate, etc.These may be used individually or in combination of two or more types.

[0074] From the viewpoint of improving photocurability and coating hardness, the content of (meth)acrylate monomer in the curable resin composition is preferably 5 to 7% by mass, and more preferably 5.5 to 6.0% by mass, based on the solid content of 100% by mass of the curable resin composition.

[0075] (Curing agent) A curable resin composition may contain a curing agent. The curing agent accelerates the thermosetting reaction and is used to further improve properties such as adhesion, chemical resistance, and heat resistance.

[0076] Examples of curing agents include imidazoles such as imidazole, alkyl-substituted imidazole, and benzimidazole; guanamines such as acetoguanamine and benzoguanamine; polyamines such as diaminodiphenylmethane, m-phenylenediamine, m-xylenediamine, diaminodiphenylsulfone, dicyandiamide, urea, urea derivatives, melamine, and polybasic hydrazides; organic salts and / or epoxy adducts thereof; amine complexes of boron trifluoride; and ethyldiamino-S-tri Triazine derivatives such as din, 2,4-diamino-S-triazine, and 2,4-diamino-6-xylyl-S-triazine; amines such as trimethylamine, triethanolamine, N,N-dimethyloctylamine, N-benzyldimethylamine, pyridine, N-methylmorpholine, hexa(N-methyl)melamine, 2,4,6-tris(dimethylaminophenol), tetramethylguanidine, and m-aminophenol; polyvinylphenol, polyvinylphenol brominated, and phenylphenol. Examples of conventionally known curing agents include polyphenols such as nol novolac and alkylphenol novolac; organic phosphins such as tributylphosphine, triphenylphosphine, and tris-2-cyanoethylphosphine; phosphonium salts such as tri-n-butyl(2,5-dihydroxyphenyl)phosphonium bromide and hexadecyltributylphosphonium chloride; quaternary ammonium salts such as benzyltrimethylammonium chloride and phenyltributylammonium chloride; the aforementioned polybasic acid anhydrides; photocationic polymerization catalysts such as diphenyliodonium tetrafluoroboroate, triphenylsulfonium hexafluoroantimonate, and 2,4,6-triphenylthiopyrillium hexafluorophosphate; styrene-maleic anhydride resins; equimolar reaction products of phenyl isocyanate and dimethylamine, equimolar reaction products of organic polyisocyanates such as tolylene diisocyanate and isophorone diisocyanate with dimethylamine, and metal catalysts. The curing agents can be used individually or in mixtures of two or more.

[0077] From the viewpoint of ensuring the strength of the cured coating film, the content of the curing agent in the curable resin composition is preferably 1.0 to 2.5% by mass, and more preferably 1.5 to 2.0% by mass, based on the solid content of 100% by mass of the thermosetting resin.

[0078] (Inorganic Filler) The curable resin composition used in the present invention may contain an inorganic filler. By including an inorganic filler, the opacity of the cured product can be improved and the matte finish of the surface can be adjusted.

[0079] Examples of inorganic fillers include silica such as talc, mica, amorphous silica, crystalline silica, fused silica, and spherical silica, as well as kaolin, montmorilloid, montmorillonite, clay, Neuburg silica particles, boehmite, hydrotalcite, zeolite, silicon nitride, aluminum nitride, calcium zirconate, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, barium titanate, calcium carbonate, calcium silicate, and lithium carbonate. Among these, silica and barium sulfate are preferred from the viewpoint of dispersibility. These may be used individually or in combination of two or more. The inorganic fillers may optionally be subjected to various surface treatments such as insulation treatment and high dispersibility treatment.

[0080] The shape of the inorganic filler is not particularly limited and may include spherical, fibrous, plate-like, irregular, balloon-like, and so on.

[0081] While inorganic fillers with an average particle size of 10 μm or less are preferably used, from the viewpoint of dispersibility, 0.01 to 3.0 μm is preferred, and 0.1 to 1.0 μm is more preferred. The average particle size can be measured using a laser diffraction / scattering device.

[0082] In a curable resin composition, the content of inorganic fillers is preferably 25 to 45% by mass, and more preferably 30 to 40% by mass, based on the solid content of 100% by mass of the solid content of the curable resin composition, from the viewpoint of improving scratch resistance and adjusting the matte finish.

[0083] (Organic Solvents) The curable resin composition may contain organic solvents for purposes such as its preparation or viscosity adjustment when applying the curable resin composition to the first film. Examples of organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, and petroleum-based solvents. More specifically, examples include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, diethylene glycol monoethyl ether acetate (carbitol acetate), dipropylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and propylene glycol monobutyl ether acetate; alcohols such as ethanol, propanol, ethylene glycol, and propylene glycol; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. Such organic solvents may be used individually or as a mixture of two or more types.

[0084] The amount of organic solvent in the curable resin composition can be appropriately changed depending on the components of the curable resin composition and is not particularly limited, but for example, it is preferably 35 to 60% by mass of the total amount of the curable resin composition. Similarly, the solid content concentration of the curable resin composition is not particularly limited, but for example, it is preferably 40 to 55% by mass, and more preferably 45 to 50% by mass.

[0085] (Other Additives) The curable resin composition may optionally contain further additives such as polymerization inhibitors, curing agents, surfactants, co-sensitizers, ultraviolet absorbers, antioxidants, ion catchers, coupling agents, tackifiers, and surface modifiers, to the extent that the effects of the present invention can be exhibited.

[0086] The content of other additives in the curable resin composition is preferably 0.01 to 10% by mass in terms of solid content, relative to 100% by mass of the solid content of the curable resin composition.

[0087] (Preparation of Curable Resin Composition) The curable resin composition is prepared as a homogeneous liquid composition by mixing a (meth)acrylate resin, a photopolymerization initiator, a thermosetting resin, a colorant, and optionally a (meth)acrylate monomer, a curing agent, an inorganic filler, an organic solvent, and other additives.

[0088] The viscosity of the curable resin composition at 25°C is preferably 1 to 10 dPa·s, and more preferably 4 to 8 dPa·s, from the viewpoint of coatability. The viscosity can be measured in accordance with JIS Z 8803:2011, section 10, "Method for measuring viscosity using a cone-plate rotational viscometer," at 25°C, 50 rpm, and 30 seconds, using a cone rotor of 1°34' × R24 and a cone-plate viscometer (Toki Sangyo Co., Ltd., TVE-33H).

[0089] <Method for Manufacturing a Laminate> The laminate of the present invention can be manufactured by applying the curable resin composition onto the first film and drying it to form a resin layer. Specifically, the curable resin composition constituting the resin layer can be diluted with an organic solvent of any choice to adjust to an appropriate viscosity, applied to the first film to a uniform thickness using a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, etc., and dried to volatilize the organic solvent in the curable resin composition, thereby forming a resin layer.

[0090] There are no particular restrictions on the amount of curable resin composition to be applied, but generally, the film thickness after drying is appropriately selected within the range of 1 to 150 μm, preferably 10 to 60 μm.

[0091] Drying after applying a curable resin composition is primarily performed to volatilize (evaporate drying) the solvent contained in the curable resin composition. Drying is preferably carried out at a temperature of 50 to 130°C for 1 to 30 minutes. Drying can be carried out using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, etc.

[0092] In one embodiment, after forming a resin layer on the first film, it is preferable to further laminate a peelable second film on the surface of the resin layer opposite to the first film, for purposes such as preventing dust from adhering to the surface of the resin layer. The second film is peeled off from the resin layer before lamination when laminating the substrate so that the resin layer side of the laminate is in contact with it. As the second film, for example, polyethylene film, polytetrafluoroethylene film, polypropylene film, surface-treated paper, etc., it is sufficient that the adhesive force between the resin layer and the second film is less than the adhesive force between the resin layer and the first film when the second film is peeled off.

[0093] The thickness of the second film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0094] 2. Cured product In one embodiment, a cured product of the resin layer of the laminate of the present invention is provided. The cured product of the present invention is obtained by curing the resin layer of the laminate of the present invention. The cured product of the present invention is preferably, for example, a solder resist layer with a thickness of 1 to 150 μm, and more preferably a matte solder resist layer.

[0095] The cured product of the present invention satisfies the following relationship between the skewness Rsk (μm), maximum peak height Rp (μm), and maximum valley depth Rv (μm) of the surface of the cured product: -3 ≤ Rsk ≤ -1 and 2 ≤ Rv / Rp ≤ 5.

[0096] The skewness Rsk of the cured product of the present invention is -3 μm or more and -1 μm or less, preferably -2.5 μm or more and -1.1 μm or less. Furthermore, the ratio of the maximum peak height to the maximum valley depth (Rv / Rp) of the cured product of the present invention is 2 or more and 5 or less, preferably 2.2 or more and 4.1 or less. By being within the above range, a good matte finish is obtained, and properties such as resolution, scratch resistance, opacity, and insulation reliability are also good.

[0097] In this specification, the skewness Rsk, maximum peak height Rp, and maximum valley depth Rv of the cured product can be measured in accordance with JIS B 0601 using a shape measuring laser microscope (VX-100) manufactured by Keyence Corporation. An observation image is acquired using the observation application (VK-H1XV) in shape measurement mode with a 100x objective lens. Then, using the analysis application (VK-H1XA), the values ​​of Rsk, Rp, and Rv are measured at five locations within a 50 μm × 50 μm area, and their averages are defined as the "skewness Rsk," "maximum peak height Rp," and "maximum valley depth Rv" in this invention.

[0098] In one embodiment, the 60° gloss of the cured product of the present invention is preferably 5 to 30, and more preferably 19 to 26, from the viewpoint of matte finish.

[0099] In this specification, the 60° gloss of the cured product can be measured in accordance with JIS Z 8741-1997. First, as a premise, on a surface with a refractive index of 1.567, the intensity of light with a reflectivity of 10% at an incident angle of 60° is set to gloss 100, and the intensity of light with a reflectivity of 0% is set to 0. Thus, one-hundredth of the intensity of light with a reflectivity of 10% corresponds to gloss 1. The intensity of light on the surface of the cured film provided on the substrate is measured using a reflectometer with geometric conditions at an incident angle of 60°. Then, the gloss is calculated by dividing the obtained light intensity by the value of one-hundredth of the intensity of light with a reflectivity of 10% as described above. In a simpler way, the gloss of the surface of the cured product can be measured using a digital angle-bending gloss meter (Micro-Tri-Gloss, manufactured by BYK Gardener). Note that "60° glossiness (Gs(60°))" is the glossiness value when the incident angle is 60° and the receiving angle is 60°.

[0100] 3. In one embodiment, a substrate is provided comprising a cured resin layer of the laminate of the present invention. In one embodiment, the substrate can be manufactured by the following method: i) The laminate is bonded to a substrate so that the resin layer of the laminate is in contact with the substrate. ii) Exposure is performed on the first film of the laminate. iii) The first film is peeled off the laminate and developed to form a patterned resin layer on the substrate. iv) The patterned curable resin layer is cured by light and / or heat to form a cured product.

[0101] Regarding step i) above, examples of the substrate include printed circuit boards with circuits pre-formed with copper, flexible printed circuit boards, paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / nonwoven fabric epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, copper-clad laminates using fluororesin / polyethylene / polyphenylene ether, polyphenylene oxide / cyanate, etc., metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate films, glass substrates, ceramic substrates, wafers, etc.

[0102] Lamination of the laminate onto a base material is preferably carried out under pressure and heating using a vacuum laminator or the like. When such a vacuum laminator is used, even if the surface of the circuit board has irregularities in the case of using a circuit-formed substrate, the film laminate adheres closely to the circuit board, so no air bubbles are incorporated, and the filling property for recesses on the substrate surface is also improved. The pressurization condition is preferably about 0.1 to 2.0 MPa, and the heating condition is preferably 40 to 120°C. When the laminate of the present invention comprises a second film, the second film is peeled from the laminate to expose the resin layer, and then the laminate is bonded onto the base material.

[0103] In the above step ii), exposure (light irradiation) is performed from above the first film of the laminate. Through this step, only the resin layer in the exposed area is cured. The exposure step is not particularly limited. For example, exposure may be selectively carried out with active energy rays through a photomask having a desired pattern formed thereon by a contact (or non-contact) method, or the desired pattern may be exposed with active energy rays by a direct drawing apparatus.

[0104] As an exposure machine used for exposure, any device equipped with a high-pressure mercury vapor lamp, an ultra-high pressure mercury vapor lamp, a metal halide lamp, a mercury short arc lamp or the like and capable of irradiating ultraviolet rays in a range of 350 to 450 nm is acceptable. Furthermore, a direct drawing apparatus (for example, a laser direct imaging apparatus that directly draws an image with a laser based on CAD data from a computer) can also be used. The lamp light source or laser light source of the direct drawing apparatus may have a maximum wavelength in the range of 350 to 450 nm. The exposure dose for image formation varies depending on the film thickness and the like, but is generally 10 to 1000 mJ / cm ２ , preferably 20 to 800 mJ / cm ２ .

[0105] In step iii) above, after exposure, the first film is peeled off the laminate and developed to form a patterned resin layer on the substrate. In the areas of the resin layer that are not patterned, the surface of the resin layer is formed to be uneven by exposure through the first film. If the properties are not impaired, the first film may be peeled off the laminate after bonding the laminate to the substrate and before exposure, and the exposed resin layer may be exposed and developed.

[0106] The development process is not particularly limited, and methods such as dipping, showering, spraying, and brushing can be used. Furthermore, alkaline aqueous solutions such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, and tetramethylammonium hydroxide can be used as the developing solution.

[0107] In step iv) above, the patterned resin layer is cured by light and / or heat to form a cured product. This step is called main curing or additional curing, and it promotes the polymerization of unreacted monomers in the exposed resin layer, and further, it can heat-cure the carboxyl group-containing photosensitive resin and epoxy resin to reduce the amount of remaining carboxyl groups.

[0108] Curing may be performed by heat curing after light irradiation, by light irradiation after heat curing, by light irradiation alone, or by heat curing alone, but it is preferable to perform heat curing after light irradiation. Performing light curing first can suppress the flow of the resin even during heat curing, and the formed surface may be maintained.

[0109] Light irradiation can be carried out in the same manner as the exposure described above, but it is preferable to use a stronger irradiation energy than that used during exposure. For example, 500 to 3000 mJ / cm². ２ This can be done. Furthermore, thermosetting can be carried out under heating conditions of 100 to 200°C for about 20 to 90 minutes.

[0110] The substrate of the present invention can be preferably used in applications such as automobiles, ships, trains, robots, machine tools, factory power distribution boards, solar cells, and electronic components (LEDs, sensors, semiconductors, circuit boards, displays, home appliances, optical communication / optical circuits, optical recording, magnetic recording, etc.).

[0111] The present invention will be further described below with reference to examples, but the present invention is not limited thereto.

[0112] <Manufacturing Example 1: Synthesis of Acrylate Resin A> In an autoclave equipped with a thermometer, a nitrogen introduction device / alkylene oxide introduction device, and a stirring device, 119.4 parts of cresol novolac resin (Shonol CRG-951, manufactured by Aica Kogyo Co., Ltd., OH equivalent: 119.4), 1.19 parts of potassium hydroxide, and 119.4 parts of toluene were introduced. The system was then heated and the temperature increased while stirring and purging with nitrogen. Next, 63.8 parts of propylene oxide were gradually added dropwise to 125-132°C and 0-4.8 kg / cm³. ２The mixture was reacted for 16 hours. After cooling to room temperature, 1.56 parts of 89% phosphoric acid were added to the reaction solution and mixed to neutralize the potassium hydroxide, yielding a propylene oxide reaction solution of novolac-type cresol resin with a solid content of 62.1% and a hydroxyl value of 182.2 mg KOH / g (307.9 g / eq.). This solution had an average of 1.08 moles of propylene oxide added per equivalent of phenolic hydroxyl groups. 293.0 parts of the obtained propylene oxide reaction solution of novolac-type cresol resin, 43.2 parts of acrylic acid, 11.53 parts of methanesulfonic acid, 0.18 parts of methylhydroquinone, and 252.9 parts of toluene were introduced into a reactor equipped with a stirrer, thermometer, and air blowing tube, and the mixture was reacted at 110°C for 12 hours while blowing air at a rate of 10 ml / min and stirring. The water produced by the reaction was distilled off as an azeotropic mixture with toluene, with 12.6 parts of water being distilled off. The mixture was then cooled to room temperature, neutralized with 35.35 parts of 15% sodium hydroxide aqueous solution, and then washed with water. Toluene was then removed by distillation in an evaporator while substituting with 118.1 parts of diethylene glycol monoethyl ether acetate to obtain a novolac-type acrylate resin solution. Next, 332.5 parts of the obtained novolac-type acrylate resin solution and 1.22 parts of triphenylphosphine were introduced into a reactor equipped with a stirrer, thermometer, and air blowing tube. Air was blown in at a rate of 10 ml / min, and while stirring, 60.8 parts of tetrahydrophthalic anhydride were gradually added, and the mixture was reacted at 95-101°C for 6 hours. After cooling, the mixture was removed. In this way, a solution of acrylate resin A with a solid content of 65% and an acid value of 87.7 mg KOH / g of solid content was obtained. Furthermore, the polymerization average molecular weight of acrylate resin A was measured by gel permeation chromatography (GPC) using polystyrene as a standard substance in accordance with JIS-K-7252-1 (published in 2008), and was found to be 2600.

[0113] <Production Example 2: Synthesis of Acrylate Resin B> In a flask equipped with a condenser and a stirrer, 456 parts of bisphenol A, 228 parts of water, and 649 parts of 37% formalin were charged. Maintaining a temperature of 40°C or lower, 228 parts of 25% sodium hydroxide aqueous solution were added. After the addition was complete, the mixture was reacted at 50°C for 10 hours. After the reaction was complete, the mixture was cooled to 40°C and neutralized to pH 4 with 37.5% phosphoric acid aqueous solution while maintaining a temperature of 40°C or lower. The mixture was then allowed to stand and the aqueous layer was separated. After separation, 300 parts of methyl isobutyl ketone were added and dissolved uniformly. The mixture was then washed three times with 500 parts of distilled water, and water, solvent, etc. were removed under reduced pressure at a temperature of 50°C or lower. The obtained polymethylol compound was dissolved in 550 parts of methanol to obtain 1230 parts of methanol solution of the polymethylol compound. A portion of the obtained methanol solution of the polymethylol compound was dried in a vacuum dryer at room temperature, and the solid content was 55.2%. 500 parts methanol solution of the obtained polymethylol compound and 440 parts 2,6-xylenol were charged and uniformly dissolved at 50°C. After uniform dissolution, methanol was removed under reduced pressure at a temperature below 50°C. Then 8 parts oxalic acid was added and the mixture was reacted at 100°C for 10 hours. After the reaction was complete, the distillate was removed under reduced pressure at 180°C and 50 mmHg to obtain 550 parts novolac resin B. Furthermore, 130 parts of the above novolac resin B, 2.6 parts 50% sodium hydroxide aqueous solution, and 100 parts toluene / methyl isobutyl ketone (mass ratio = 2 / 1) were charged into an autoclave equipped with a thermometer, a nitrogen introduction device / alkylene oxide introduction device, and a stirring device. The system was purged with nitrogen while stirring, and then heated to 150°C and 8 kg / cm². ２Ethylene oxide was gradually introduced and the reaction was carried out. The reaction continued for approximately 4 hours until the gauge pressure reached 0.0 kg / cm², after which it was cooled to room temperature. 3.3 parts of 36% hydrochloric acid aqueous solution were added to this reaction solution and mixed to neutralize the sodium hydroxide. The neutralization reaction product was diluted with toluene, washed three times with water, and desolvented using an evaporator to obtain an ethylene oxide adduct of novolac resin A with a hydroxyl value of 175 g / eq. This adduct contained an average of 1 mole of ethylene oxide per equivalent of phenolic hydroxyl groups. 175 parts of the ethylene oxide adduct of the novolac resin B obtained in this way, 50 parts of acrylic acid, 3.0 parts of p-toluenesulfonic acid, 0.1 parts of hydroquinone monomethyl ether, and 130 parts of toluene were charged into a reactor equipped with a stirrer, thermometer, and air blowing tube. The mixture was stirred while blowing air into it, and the temperature was raised to 115°C. The reaction was continued for another 4 hours while the water produced by the reaction was removed by distillation as an azeotrope with toluene, and then cooled to room temperature. The resulting reaction solution was washed with water using a 5% NaCl aqueous solution, and toluene was removed by distillation under reduced pressure. Diethylene glycol monoethyl ether acetate was then added to obtain an acrylate resin solution with a solid content of 68%. Next, 312 parts of the obtained acrylate resin solution, 0.1 part of hydroquinone monomethyl ether, and 0.3 parts of triphenylphosphine were charged into a four-necked flask equipped with a stirrer and reflux condenser. This mixture was heated to 110°C, 45 parts of tetrahydrophthalic anhydride were added, and the mixture was reacted for 4 hours. After cooling, the mixture was removed. In this way, a solution of acrylate resin B with a solid content of 72% and a solid content acid value of 65 mg KOH / g was obtained. Furthermore, the polymerization average molecular weight of acrylate resin B was measured by gel permeation chromatography (GPC) using polystyrene as a standard substance in accordance with JIS-K-7252-1 (published in 2008), and was found to be 9200.

[0114] <Production Example 3: Synthesis of Acrylate Resin C> In a flask equipped with a condenser and a stirrer, 456 parts of bisphenol A, 228 parts of water, and 649 parts of 37% formalin were charged. Maintaining a temperature of 40°C or lower, 228 parts of 25% sodium hydroxide aqueous solution were added. After the addition was complete, the mixture was reacted at 50°C for 10 hours. After the reaction was complete, the mixture was cooled to 40°C and neutralized to pH 4 with 37.5% phosphoric acid aqueous solution while maintaining a temperature of 40°C or lower. The mixture was then allowed to stand and the aqueous layer was separated. After separation, 300 parts of methyl isobutyl ketone were added and dissolved uniformly. The mixture was then washed three times with 500 parts of distilled water, and water, solvent, etc. were removed under reduced pressure at a temperature of 50°C or lower. The obtained polymethylol compound was dissolved in 550 parts of methanol to obtain 1230 parts of methanol solution of the polymethylol compound. A portion of the obtained methanol solution of the polymethylol compound was dried in a vacuum dryer at room temperature, and the solid content was 55.2%. 500 parts methanol solution of the obtained polymethylol compound and 440 parts 2,6-xylenol were charged and uniformly dissolved at 50°C. After uniform dissolution, methanol was removed under reduced pressure at a temperature below 50°C. Then 8 parts oxalic acid was added and the mixture was reacted at 100°C for 10 hours. After the reaction was complete, the distillate was removed under reduced pressure at 180°C and 50 mmHg to obtain 550 parts novolac resin C. Furthermore, 130 parts of the above novolac resin C, 2.6 parts 50% sodium hydroxide aqueous solution, and 100 parts toluene / methyl isobutyl ketone (mass ratio = 2 / 1) were charged into an autoclave equipped with a thermometer, a nitrogen introduction device / alkylene oxide introduction device, and a stirring device. The system was purged with nitrogen while stirring, and then heated to 150°C and 8 kg / cm². ２ Then, 45 parts of ethylene oxide were gradually introduced and the reaction was carried out. The reaction was carried out under a gauge pressure of 0.0 kg / cm². ２The reaction was continued for approximately 4 hours until the reaction reached a certain point, after which it was cooled to room temperature. 3.3 parts of 36% hydrochloric acid aqueous solution were added to this reaction solution and mixed to neutralize the sodium hydroxide. The neutralization reaction product was diluted with toluene, washed three times with water, and desolvented using an evaporator to obtain an ethylene oxide adduct of novolac resin A with a hydroxyl value of 175 g / eq. This adduct contained an average of 1 mole of ethylene oxide per equivalent of phenolic hydroxyl groups. 175 parts of the ethylene oxide adduct of novolac resin C obtained in this way, 75 parts of methacrylic acid, 3.0 parts of p-toluenesulfonic acid, 0.1 parts of hydroquinone monomethyl ether, and 130 parts of toluene were charged into a reactor equipped with a stirrer, thermometer, and air blowing tube. The mixture was stirred while blowing air into it, the temperature was raised to 115°C, and the reaction was continued for another 4 hours while distilling off the water produced by the reaction as an azeotropic mixture with toluene, after which it was cooled to room temperature. The resulting reaction solution was washed with a 5% NaCl aqueous solution, and toluene was removed by vacuum distillation. Diethylene glycol monoethyl ether acetate was then added to obtain a solution of acrylate resin C with a solid content of 68%. The polymerization average molecular weight of acrylate resin C was measured by gel permeation chromatography (GPC) using polystyrene as a standard substance in accordance with JIS-K-7252-1 (published in 2008), and was found to be 7400.

[0115] <Production Example 4: Synthesis of Acrylate Resin D> 650 parts by mass of diethylene glycol monoethyl ether acetate was charged with 1070 g of orthocresol novolac type epoxy resin (DIC Corporation, EPICLON N-695, softening point 95°C, epoxy equivalent 214, average number of functional groups 7.6), 360 g of acrylic acid, and 1.5 g of hydroquinone. The mixture was heated to 100°C and stirred until uniformly dissolved. Next, 4.3 parts by mass of triphenylphosphine was charged, and the mixture was heated to 110°C and reacted for 2 hours. Then, an additional 1.6 parts by mass of triphenylphosphine was added, and the temperature was raised to 120°C and the reaction was carried out for a further 12 hours. 525 g of aromatic hydrocarbon (Standard Petroleum Osaka Sales Office, T-Sol 150) and 608 g (4.0 mol) of tetrahydrophthalic anhydride were charged into the resulting reaction solution and the mixture was reacted at 110°C for 4 hours. Furthermore, 142.0 g of glycidyl methacrylate was added to the resulting reaction solution, and the reaction was carried out at 115°C for 4 hours. In this way, a solution of acrylate resin D with a solids content acid value of 77 mg KOH / g and a solids content of 65% was obtained. The polymerization average molecular weight of acrylate resin D was measured by gel permeation chromatography (GPC) using polystyrene as a standard substance in accordance with JIS-K-7252-1 (published in 2008), and was found to be 11000.

[0116] <Manufacturing Example 5: Manufacturing of Film 2> ISO-butylated melamine resin (Amidia L-125-60, 60% solids, manufactured by DIC Corporation) and acrylic resin for melamine baking (Acrydic A-405, 50% solids, manufactured by DIC Corporation) were mixed in a ratio of 25:75 by mass (on a solids basis), and pre-mixed with a stirrer to obtain acrylic melamine resin. Next, the obtained acrylic melamine resin was diluted with methyl ethyl ketone to prepare a resin solution with a solids concentration of 35% by mass. To this resin solution, methyl ethyl ketone was added to achieve an appropriate solid content concentration according to the thickness of the coating film. Then, a silicone resin (Cymac US-270, manufactured by Toagosei Co., Ltd.) and a filler (SOC2, spherical silica, manufactured by Admatex Co., Ltd.) adjusted to have a maximum particle size of 2 μm were added in a ratio of 59.7:0.3:108 by mass of acrylic melamine resin, silicone resin, and filler. The mixture was thoroughly stirred at room temperature to obtain a uniform coating solution. The obtained coating solution was applied to a 25 μm thick polyethylene terephthalate film (E5041, manufactured by Toyobo Co., Ltd.) and dried at 130°C for 20 seconds to produce film 2 with a coating layer. The thickness of film 2 was 27 μm.

[0117] <Materials Used> ・Acrylate resin A: Synthesized in the above manufacturing example 1. Carboxyl group-containing resin. Mw = 2600 ・Acrylate resin B: Synthesized in the above manufacturing example 2. Carboxyl group-containing resin. Mw = 9200 ・Acrylate resin C: Synthesized in the above manufacturing example 3. Carboxyl group-free resin. Mw = 7400 ・Acrylate resin D: Synthesized in the above manufacturing example 4. Carboxyl group-containing resin. Mw = 11000 ・Photopolymerization initiator 1: TPO, 2,4,6-trimethylbenzoyldipenylphosphine oxide, acylphosphine oxide-based photopolymerization initiator manufactured by Kusumoto Chemicals Co., Ltd. ・Photopolymerization initiator 2: Yueyang Kimoutain Sci-tech Co., Ltd. JMT-784, manufactured by DIC Corporation; bis(η5-2,4-cyclopentadiene-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl) titanium, oxime-based photopolymerization initiator; thermosetting resin 1: N-870, bisphenol A novolac type epoxy resin; thermosetting resin 2: NC-3000H, novolac type epoxy resin; thermosetting resin 3: HP-7200L, epoxy resin with a dicyclopentadiene skeleton; coloring agent 1: red pigment, Pigment red K3580; coloring agent 2: yellow pigment, Pigment yellow 147 • Coloring agent 3: Blue pigment, phthalocyanine blue • Coloring agent 4: Black pigment, carbon black • (meth)acrylate monomer 1: Neomer DA-600, dipentaerythritol hexaacrylate, manufactured by Sanyo Chemical Industries, Ltd. • (meth)acrylate monomer 2: Laromer LR8863, EO-modified trimethylolpropane triacrylate, manufactured by BASF Japan Ltd. • Hardener 1: Melamine • Hardener 2: Dicyandiamide (DICY) • Inorganic filler 1: B-100, barium sulfate, manufactured by Sakai Chemical Industry Co., Ltd. • Inorganic filler 2: SO-C6, spherical silica, manufactured by Admatex Co., Ltd. • Additive: Kinopower QS-30, polymerization inhibitor, manufactured by Air Water Performance Chemical Co., Ltd.

[0118] <Preparation of Curable Resin Compositions> Each component shown in Table 1 was mixed in the amounts shown in Table 1, pre-mixed using a stirrer, and then kneaded using a three-roll mill to prepare curable resin compositions 1 to 9. Unless otherwise specified, the values ​​in Table 1 represent the solid content in parts by mass.

[0119]

[0120] <Preparation of Films> The following films were prepared as the films (first films) that make up the laminate: • Film 1: Commercially available biaxially oriented polyester film, manufactured by Unitika Ltd., PTHA-25, Rsk = 1.98 • Film 2: Polyethylene terephthalate film produced in the above manufacturing example 5, Rsk = 0.44 of the coated surface

[0121] The skewness Rsk of the film was measured in accordance with JIS B 0601:2001 using a shape-measuring laser microscope VX-100 (manufactured by Keyence Corporation) in shape measurement mode. Specifically, in the shape measurement mode of the shape-measuring laser microscope, the observation application VK-H1XV was launched, film 1 was placed on the X-Y stage, and the focus was set using autofocus with a 100x objective lens in shape measurement mode. The Z axis was controlled by arbitrary selection to adjust the focus to the optimal position. Then, the observation image was acquired in either automatic measurement mode or manual measurement mode. Next, the analysis application VK-H1XA was launched, and the skewness Rsk was measured at five locations within a 50 μm x 50 μm area, and the average value was calculated to determine the film's Rsk.

[0122] <Preparation of Laminate> To the curable resin composition prepared as described above, propylene glycol monomethyl ether acetate was added and stirred so that the solid content concentration of the curable resin composition was 48% by mass. This mixture was then applied to the surface of each film (for film 2, the coated side) using an applicator (gap 50 μm), and dried in a hot air circulating drying oven at 80°C for 30 minutes to produce a laminate having a resin layer with a thickness of 15 ± 2 μm after drying.

[0123] <Example 1> A test substrate was fabricated using the laminate prepared above and evaluated. The results are shown in Table 2.

[0124] <Preparation of Test Substrate> The basic procedure for preparing the test substrate is described below. (i) The surface of a copper-clad laminate (95 mm x 150 mm x 0.8 mm thick) was etched, and the resin layer of the laminate was bonded to the etched side of the substrate. Subsequently, using a vacuum laminator (Nikko Materials Co., Ltd. CVP-300), the temperature was set to 80°C, vacuum at 3 hPa for 30 seconds, and pressure at 0.4 MPa for 30 seconds, followed by a temperature of 70°C and pressure of 8 kgf / cm². ２ (ii) Next, the substrate and the resin layer were heated and laminated for 60 seconds to ensure close contact. (ii) Then, using an exposure apparatus equipped with a high-pressure mercury lamp (DI exposure machine, Mns-60, manufactured by Oak Manufacturing Co., Ltd.), exposure was performed from the film side at 23.5 ± 0.5°C with an exposure dose of 300 mJ / cm². ２ After exposure, the film was peeled off. (iii) After peeling, the film was developed for 60 seconds at 30°C and a spray pressure of 0.2 MPa using a 1% sodium carbonate aqueous solution, and then washed with deionized water for 60 seconds at 25°C and a spray pressure of 0.1 MPa. (iv) Next, it was subjected to 1000 mJ / cm² in a UV conveyor furnace equipped with a high-pressure mercury lamp. ２ After photocuring the resin layer by irradiating it with the specified exposure level, the cured resin layer was heated at 160°C for 60 minutes to form a test substrate.

[0125] <Measurement of Rp, Rv, and Rsk on the surface of the cured material> The maximum peak height Rp, maximum valley depth Rv, and skewness Rsk of the cured surface of the test substrate prepared as described above were measured in accordance with JIS B 0601:2001 using a shape measurement laser microscope VX-100 (manufactured by Keyence Corporation) in shape measurement mode. Specifically, in the shape measurement mode of the shape measurement laser microscope, the observation application VK-H1XV was launched, film 1 was placed on the X-Y stage, and the focus was set using autofocus with a 100x objective lens in shape measurement mode. The Z axis was controlled by arbitrary selection to adjust the focus to the optimal position. Then, observation images were acquired in automatic measurement mode or manual measurement mode. Next, the analysis application VK-H1XA was launched, and measurements of Rp, Rv, and Rsk were taken at five locations within a 50 μm x 50 μm area. The average values ​​were then calculated to determine the maximum peak height Rp, maximum valley depth Rv, and skewness Rsk on the hardened surface. The results are shown in Table 2.

[0126] <Measurement of Glossiness of the Cured Surface> The Gs (60°) of the cured surface was measured three times using a digital angle-bending gloss meter (BYK Gardener, Micro-Tri-Gloss), and the average value was calculated. The results are shown in Table 2.

[0127] <Scratch Resistance: Roller Marks After Development> The appearance of the test substrate after step (iii) in the manufacturing process of the above test substrate was visually inspected to evaluate the presence or absence of roller marks from the developing machine. The results are shown in Table 2. A and B were judged as passing, and C as failing. A: No roller marks. B: Some roller marks present. C: Roller marks present across the entire surface.

[0128] <Scratch Resistance: Coating Cracks After Development> During step (ii) of the above test substrate preparation, exposure was performed through a photomask having a width of 100 μm and a space of 100 μm. Subsequently, the substrate that underwent step (iii) above was observed at 500x magnification using an optical microscope (VHX-6000, manufactured by Keyence Corporation) to evaluate whether or not there were cracks in the coating. The results are shown in Table 2. A was judged as pass and C as fail. A: No coating cracks. C: Coating cracks present.

[0129] <Resolution: Sensitivity> During process (ii) of the above test substrate preparation, exposure was performed via a step tablet (Stuffer 41-step step tablet). Subsequently, on the substrate that underwent process (iii) above, the number of steps of the step tablet corresponding to the remaining portion after development was checked, and the sensitivity was evaluated. The results are shown in Table 2. A and B were judged as passing, and C as failing. A: 7 steps or more. B: 4 to 6 steps. C: 3 steps or less.

[0130] <Resolution: SRO Accuracy> During process (ii) of the above test substrate fabrication, a φ80 μm SRO pattern was exposed. Subsequently, the φ80 μm portion of the SRO design value was observed and measured using a SEM (JSM-6610LV, magnification: 1000x) on the substrate after processes (iii) and (iv) above. Then, the rate of change from the design value was calculated and evaluated according to the following formula. The results are shown in Table 2. Note that A was judged as pass and C as fail. Formula: (Rate of change) = 100 - (SRO design value) / (Measured value) × 100 A: Rate of change within ±20%. C: Rate of change less than -20% or greater than 20%.

[0131] <Hiddenness> Before step (i) in the preparation of the test substrate described above, the substrate was scratched with a cutter, and then the test substrate was prepared according to the method for preparing the test substrate described above. The prepared test substrate was visually inspected, and the hidingness of scratches on the copper circuit was evaluated. The results are shown in Table 2. A and B were judged as passing, and C as failing. A: No scratches are visible. B: Scratches may be visible depending on the observation angle. C: Scratches are visible regardless of the observation angle.

[0132] <Insulation Reliability: B-HAST Resistance> The test substrate was manufactured according to the method for manufacturing the test substrate, except that a substrate with a comb-shaped electrode pattern of L / S = 20 μm / 20 μm was used in step (i) of the manufacturing process of the test substrate. A bias voltage of DC 5V was applied, and the insulation resistance value was 10 at 130°C / 85%RH. ６The time taken to reach the following conditions was measured. Five measurements were taken, and the average time was calculated and evaluated. The results are shown in Table 2. A and B were judged as passing, and C as failing. A: 300 hours or more. B: 200 hours or more but less than 300 hours. C: Less than 200 hours.

[0133] <Examples 2-5, Comparative Examples 1-5> Laminates were prepared in the same manner as in Example 1, except that the curable resin composition and film were changed as shown in Table 2. Test substrates were prepared using the obtained laminates and evaluated. The results are shown in Table 2.

[0134]

[0135] The laminates of Examples 1 to 5 exhibited good matte finish and also showed good characteristics such as scratch resistance, resolution, opacity, and insulation reliability. On the other hand, the laminates of Comparative Examples 1 to 5 were outside the scope of the present invention and therefore performed inferiorly to the present invention in at least one of the specified areas.

Claims

1. A laminate comprising a first film and a resin layer formed from a curable resin composition provided on one surface of the first film, wherein the curable resin composition comprises a (meth)acrylate resin, a photopolymerization initiator, a thermosetting resin, and a colorant, wherein the (meth)acrylate resin comprises a carboxyl group-containing resin (A) with a weight-average molecular weight of 2000 or more and less than 8000, a carboxyl group-containing resin (B) with a weight-average molecular weight of 8000 or more and 14000 or less, and a carboxyl group-free resin (C) with a weight-average molecular weight of 2000 or more and 8000 or less, wherein the content of the carboxyl group-containing resin (B) in the curable resin composition is 30% by mass or more in terms of solid content, relative to 100% by mass of the total solid content of the (meth)acrylate resin. A laminate in which, after exposing the laminate to cure the resin layer, the resin layer peeled off from the first film is further cured by light and / or heat, wherein the skewness Rsk (μm), maximum peak height Rp (μm), and maximum valley depth Rv (μm) of the surface that was in contact with the first film satisfy the following relationship: -3 ≤ Rsk ≤ -1 and 2 ≤ Rv / Rp ≤ 5.

2. The laminate according to claim 1, wherein the skewness Rsk (μm) of the surface of the first film in contact with the resin layer satisfies the following relationship: 1 ≤ Rsk ≤ 2.

5.

3. The laminate according to claim 1, wherein the mass ratio (A):(B):(C) of the solid content of the (meth)acrylate resin in the curable resin composition is 15-50:30-65:10-30.

4. A cured resin layer of the laminate according to claim 1.

5. A substrate comprising the cured product described in claim 4.

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