JP6232168B2 - Solder resist composition, film, coated printed wiring board, film manufacturing method, and coated printed wiring board manufacturing method - Google Patents

Description

  The present invention relates to a solder resist composition, a film, a coated printed wiring board, a method for producing a film, and a method for producing a coated printed wiring board.

  A film such as a solder resist layer is formed on the printed wiring board to protect the wiring and prevent a short circuit when mounting the component. In addition, characters, symbols or the like that display product information may be marked on the printed wiring board.

  As a coated wiring board having excellent marking visibility, a coated wiring board in which a second coating and a first coating are formed in this order on a printed wiring board is known (Japanese Patent No. 5634416). The second coating functions as a colored layer. The first coating includes a first region and a second region having higher light transmittance than the first region. The first film is formed from a photosensitive film-forming composition containing an organic compound having a specific melting point and not having photopolymerizability. In this case, a first film having the first region and the second region can be produced only by partially varying the exposure amount when exposing the coating film formed from the film forming composition.

  In this coated wiring board, for example, when the first film (solder resist layer) contains a green colorant and the second film (solder resist layer) contains a black colorant, The appearance color of the area appears green, and the appearance color of the second area is black by mixing the color of the first film (green) and the color of the second film that is visible through the first film (black). Or it looks dark green. Thereby, the difference between the first region and the second region is clearly visually recognized, and the marking visibility is increased.

  However, in the coated wiring board described in Patent Document 1, since a two-layered film including the first film and the second film is formed on the printed wiring board, the productivity is lowered. Moreover, since the film thickness of the entire coating covering the printed wiring board is thick, it is difficult for exposure (UV light) to sufficiently reach from the surface layer to the deep part of the two-layer coating film when the coated wiring board is manufactured. As a result, the film was not sufficiently cured, and there was a possibility that the adhesion between the printed wiring board and the two-layer film was not sufficient.

  The present invention has been made in view of the above reasons, and a solder resist composition capable of producing a film having a marking having excellent visibility even in a single layer only by partially varying the exposure amount during exposure. It is an object of the present invention to provide a product, a coating produced from this solder resist composition, a coated printed wiring board provided with this coating, a method for producing a coating, and a method for producing a coated printed wiring board.

  The solder resist composition according to one aspect of the present invention includes one or more photopolymerizable compounds (B) selected from the group consisting of a carboxyl group-containing resin (A), a photopolymerizable monomer, and a photopolymerizable prepolymer, light It contains a polymerization initiator (C), a crystalline epoxy resin (D) having a melting point of 130 ° C. or higher, and a blue dispersant (E).

  The film which concerns on 1 aspect of this invention consists of hardened | cured material of the said soldering resist composition, and contains the 1st area | region and the 2nd area | region where the light transmittance is higher than a said 1st area | region.

The covering printed wiring board concerning one mode of the present invention is provided with a printed wiring board and the above-mentioned coat. The printed wiring board includes an insulating layer and a copper wiring on the insulating layer. The coating covers the insulating layer and the wiring.

The method for producing a coating according to one aspect of the present invention includes:
<a> forming a coating film comprising the solder resist composition, <b> exposing the coating film, and <c> forming the coating film by heating the exposed coating film. . In the step <b>, the first portion of the coating film is irradiated with light, and the second portion of the coating film different from the first portion is not irradiated with light, or the first portion In the step <c>, by generating light bubbles in the first portion by heating, a first bubble containing bubbles in the coating is irradiated. A region and a second region that does not contain bubbles or have a lower bubble ratio than the first region are formed.

The method for producing a coated printed wiring board according to one aspect of the present invention,
<D> The solder resist composition according to any one of the first to fourth aspects, the insulating layer and the wiring on a printed wiring board including an insulating layer and a copper wiring on the insulating layer. The process of forming a coating film by arranging to cover,
<E> a step of exposing the coating film;
<F> The process of developing the said coating film after exposure with an alkaline developing solution, <g> The process of forming the said coating film by heating the said coating film after image development.

In the step <e>, the first part of the coating film is irradiated with light, and the second part different from the first part of the coating film has an exposure amount that is higher than that of the first part. Irradiate with light to lower it,
In the step <g>, by generating bubbles in the first portion by heating, the first region containing bubbles in the coating and the ratio of bubbles not containing bubbles or the first ratio A second region lower than the first region is formed.

  According to the present invention, the coating film formed from the solder resist composition is exposed, and it has a marking having excellent visibility even if it is a single layer only by partially varying the exposure amount at the time of exposure. A coating can be made.

It is general | schematic sectional drawing which shows the manufacturing method of the film printed wiring board provided with a film and a film in one Embodiment of this invention. It is general | schematic sectional drawing which shows the manufacturing method of the film printed wiring board provided with a film and a film in one Embodiment of this invention. It is general | schematic sectional drawing which shows the manufacturing method of the film printed wiring board provided with a film and a film in one Embodiment of this invention.

  Embodiments of the present invention will be described below. In the present specification, acryloyl and / or methacryloyl may be represented as (meth) acryloyl. In addition, acrylate and / or methacrylate may be represented as (meth) acrylate. Moreover, acrylic acid and / or methacrylic acid may be represented as (meth) acrylic acid.

{Solder resist composition}
The solder resist composition of the present embodiment includes one or more photopolymerizable compounds (B) selected from the group consisting of a carboxyl group-containing resin (A), a photopolymerizable monomer, and a photopolymerizable prepolymer, a photopolymerization initiator. (C), a crystalline epoxy resin (D) having a melting point of 130 ° C. or higher and a blue dispersant (E) are contained.

  When a coating film is formed from the solder resist composition of the present embodiment, and this coating film is exposed and the exposure amount at the time of this exposure is partially different, it has a marking with excellent visibility even in a single layer. A film can be formed. When a film is formed on a printed wiring board provided with copper wiring, the marking visibility is particularly excellent.

  The composition of the solder resist composition will be described in more detail.

[Carboxyl group-containing resin (A)]
The carboxyl group-containing resin (A) can impart developability with an alkaline solution, that is, alkali developability, to the coating film formed from the solder resist composition.

(Carboxyl group-containing resin (A1))
The carboxyl group-containing resin (A) can also contain a carboxyl group-containing resin (A1) having a photopolymerizable functional group (hereinafter also referred to as component (A1)). The photopolymerizable functional group is, for example, an ethylenically unsaturated group.

  As the component (A1), for example, an ethylenically unsaturated compound (a2) having a carboxyl group reacts with at least one of the epoxy groups in the epoxy compound (a1) having two or more epoxy groups in one molecule. Furthermore, a resin having a structure to which at least one compound (a3) selected from a polyvalent carboxylic acid and an anhydride thereof is added (hereinafter referred to as the first resin (a)) can be contained.

  The epoxy compound (a1) is, for example, a cresol novolak type epoxy resin, a phenol novolak type epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol A novolak type epoxy resin, a naphthalene type epoxy resin, a biphenyl type epoxy resin, or biphenyl. Contains at least one compound selected from the group consisting of aralkyl-type epoxy resins, triglycidyl isocyanurates, alicyclic epoxy resins, bisphenolfluorene-type epoxy resins, and polymers of ethylenically unsaturated compounds including compounds having an epoxy group be able to.

  The epoxy compound (a1) may contain a polymer of an ethylenically unsaturated compound (p) including the compound (p1) having an epoxy group. The raw material used for the synthesis of the polymer of the ethylenically unsaturated compound (p) may contain only the compound (p1) having an epoxy group, and does not have the compound (p1) having an epoxy group and the epoxy group. You may contain a compound (p2).

  The compound (p1) having an epoxy group can contain a compound selected from appropriate polymers and prepolymers. Specifically, the compound (p1) having an epoxy group is an epoxy cyclohexyl derivative of acrylic acid, an epoxy cyclohexyl derivative of methacrylic acid, an alicyclic epoxy derivative of acrylate, an alicyclic epoxy derivative of methacrylate, or β-methylglycidyl acrylate. And one or more compounds selected from the group consisting of β-methylglycidyl methacrylate. In particular, it is preferable that the compound (p1) having an epoxy group contains glycidyl (meth) acrylate which is widely used and easily available.

  The compound (p2) not having an epoxy group may be a compound copolymerizable with the compound (p1) having an epoxy group. Examples of the compound (p2) having no epoxy group include 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl-2-hydroxyethyl phthalate, 2- (meth) acryloyloxypropyl phthalate, Benzyl (meth) acrylate, neopentyl glycol benzoate (meth) acrylate, paracumylphenoxyethylene glycol (meth) acrylate, EO-modified cresol (meth) acrylate, ethoxylated phenyl (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate ( Degree of polymerization n = 2 to 17), ECH-modified phenoxy (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxyhexaeth Glycol (meth) acrylate, phenoxytetraethylene glycol (meth) acrylate, tribromophenyl (meth) acrylate, EO-modified tribromophenyl (meth) acrylate, EO-modified bisphenol A di (meth) acrylate, PO-modified bisphenol A di ( (Meth) acrylate, modified bisphenol A di (meth) acrylate, EO modified bisphenol F di (meth) acrylate, ECH modified phthalic acid di (meth) acrylate, trimethylolpropane benzoate (meth) acrylate, EO modified phthalic acid (meth) acrylate , EO, PO modified phthalic acid (meth) acrylate, vinyl carbazole, styrene, N-phenylmaleimide, N-benzylmaleimide, 3-maleimidobenzoic acid N-succinimid , (Meth) acrylic acid ester, hydroxyalkyl (meth) acrylate, alkoxyalkyl (which may have a linear or branched aliphatic or alicyclic group (but may partially have an unsaturated bond in the ring)) One or more compounds selected from the group consisting of (meth) acrylates and N-substituted maleimides can be contained. Examples of N-substituted maleimides include N-cyclohexylmaleimide.

  The compound having no epoxy group (p2) may further contain a compound having two or more ethylenically unsaturated groups in one molecule. By using this compound and adjusting the amount of the compound, the hardness and oiliness of the coating can be easily adjusted. Examples of the compound having two or more ethylenically unsaturated groups in one molecule include polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and pentaerythritol tri (meth). One or more compounds selected from the group consisting of acrylates can be contained.

  A polymer is obtained by polymerizing the ethylenically unsaturated compound (p) by a known polymerization method such as a solution polymerization method or an emulsion polymerization method. Specific examples of the solution polymerization method include a method of heating and stirring the ethylenically unsaturated compound (p) in a suitable organic solvent in the presence of a polymerization initiator in a nitrogen atmosphere and an azeotropic polymerization method.

  The organic solvent used for the polymerization of the ethylenically unsaturated compound (p) is, for example, one or more compounds selected from the group consisting of ketones, aromatic hydrocarbons, acetic acid esters, and dialkyl glycol ethers Can be contained. Examples of ketones include methyl ethyl ketone and cyclohexanone. Examples of aromatic hydrocarbons include toluene, xylene and the like. Examples of acetates include ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, and propylene glycol monomethyl ether acetate.

  Polymerization initiators used for the polymerization of the ethylenically unsaturated compound (p) are, for example, hydroperoxides, dialkyl peroxides, diacyl peroxides, ketone peroxides, alkyl peresters, peroxydi. One or more compounds selected from the group consisting of carbonates, azo compounds, and redox initiators can be contained. Examples of hydroperoxides include diisopropylbenzene hydroperoxide. Examples of dialkyl peroxides include dicumyl peroxide, 2,5-dimethyl-2,5-di- (t-butylperoxy) -hexane, and the like. Examples of diacyl peroxides include isobutyryl peroxide. Examples of ketone peroxides include methyl ethyl ketone peroxide. Examples of alkyl peresters include t-butyl peroxypivalate. Examples of peroxydicarbonates include diisopropyl peroxydicarbonate. Examples of the azo compound include azobisisobutyronitrile.

  The ethylenically unsaturated compound (a2) can contain a compound selected from the group consisting of appropriate polymers and prepolymers. The ethylenically unsaturated compound (a2) can contain a compound having only one ethylenically unsaturated group. Examples of the compound having only one ethylenically unsaturated group include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2 -Methacryloyloxyethylphthalic acid, β-carboxyethyl acrylate, acryloyloxyethyl succinate, methacryloyloxyethyl succinate, 2-propenoic acid, 3- (2-carboxyethoxy) -3-oxypropyl ester, 2-acryloyl Consists of oxyethyl tetrahydrophthalic acid, 2-methacryloyloxyethyl tetrahydrophthalic acid, 2-acryloyloxyethyl hexahydrophthalic acid, and 2-methacryloyloxyethyl hexahydrophthalic acid It can contain one or more compounds selected from. The ethylenically unsaturated compound (a2) can further contain a compound having a plurality of ethylenically unsaturated groups. The compound having a plurality of ethylenically unsaturated groups is, for example, one or more compounds selected from the group consisting of a polyfunctional acrylate having a hydroxyl group, and a compound obtained by reacting a difunctional anhydride with a polyfunctional methacrylate. Can be contained. Examples of the polyfunctional acrylate having a hydroxyl group and the polyfunctional methacrylate include pentaerythritol triacrylate, pentaerythritol trimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, dipentaerythritol pentaacrylate, dipentaerythritol pentamethacrylate and the like. Is mentioned.

  In particular, the ethylenically unsaturated compound (a2) preferably contains at least one of acrylic acid and methacrylic acid. In this case, since the ethylenically unsaturated group derived from acrylic acid and methacrylic acid is particularly excellent in photoreactivity, the photoreactivity of the first resin (a) is increased.

  The amount of the ethylenically unsaturated compound (a2) used is such that the carboxyl group of the ethylenically unsaturated compound (a2) is in the range of 0.4 to 1.2 mol with respect to 1 mol of the epoxy group of the epoxy compound (a1). It is preferable that the amount is such that the carboxyl group is in the range of 0.5 to 1.1 mol.

  The compound (a3) selected from the group consisting of polyvalent carboxylic acids and anhydrides thereof is, for example, selected from the group consisting of dicarboxylic acids; tribasic acid or higher polycarboxylic acids; and anhydrides of these polycarboxylic acids One or more compounds can be included. Examples of the dicarboxylic acid include phthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, methylnadic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, succinic acid, methylsuccinic acid, maleic acid, citraconic acid, glutaric acid, and itacone. An acid etc. are mentioned. Examples of the polybasic carboxylic acid having a tribasic acid or higher include cyclohexane-1,2,4-tricarboxylic acid, trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, and methylcyclohexene tetracarboxylic acid.

  The compound (a3) is used mainly for imparting redispersion and resolubility with a dilute alkaline aqueous solution to the solder resist composition by giving an acid value to the first resin (a). The amount of the compound (a3) used is adjusted so that the acid value of the first resin (a) is preferably 30 mgKOH / g or more, particularly preferably 60 mgKOH / g or more. The amount of the compound (a3) used is adjusted so that the acid value of the first resin (a) is preferably 160 mgKOH / g or less, particularly preferably 130 mgKOH / g or less.

  When the first resin (a) is synthesized, an addition reaction between the epoxy compound (a1) and the ethylenically unsaturated compound (a2), and a product (addition reaction product) and a compound (a3) obtained by the addition reaction. In the case of proceeding the addition reaction with (), a known method may be employed. For example, in the addition reaction between the epoxy compound (a1) and the ethylenically unsaturated compound (a2), the ethylenically unsaturated compound (a2) is added to the solvent solution of the epoxy compound (a1), and thermal polymerization is prohibited as necessary. A reactive solution is obtained by adding an agent and a catalyst and stirring and mixing. An addition reaction product is obtained by reacting this reactive solution at a reaction temperature of preferably 60 to 150 ° C., particularly preferably 80 to 120 ° C., by a conventional method. Examples of the thermal polymerization inhibitor include hydroquinone and hydroquinone monomethyl ether. Examples of the catalyst include tertiary amines, quaternary ammonium salts, triphenylphosphine, and triphenylstibine. Examples of tertiary amines include benzyldimethylamine and triethylamine. Examples of the quaternary ammonium salts include trimethylbenzylammonium chloride and methyltriethylammonium chloride.

  In proceeding the addition reaction between the addition reaction product and the compound (a3), the compound (a3) is added to the solvent solution of the addition reaction product, and a thermal polymerization inhibitor and a catalyst are further added as necessary, followed by stirring and mixing. By doing so, a reactive solution is obtained. The first resin (a) is obtained by reacting this reactive solution by a conventional method. The reaction conditions may be the same as in the addition reaction of the epoxy compound (a1) and the ethylenically unsaturated compound (a2). As the thermal polymerization inhibitor and the catalyst, the compound used in the addition reaction between the epoxy compound (a1) and the ethylenically unsaturated compound (a2) having a carboxyl group can be used as it is.

  The component (A1) may contain the second resin (b). The second resin (b) is obtained by reacting an ethylenically unsaturated compound having an epoxy group with a part of the carboxyl group in a polymer of ethylenically unsaturated monomers including an ethylenically unsaturated compound having a carboxyl group. It is obtained by. The ethylenically unsaturated monomer may contain an ethylenically unsaturated compound having no carboxyl group, if necessary.

  The ethylenically unsaturated compound having a carboxyl group for obtaining the second resin (b) can contain an appropriate polymer and prepolymer. For example, an ethylenically unsaturated compound having a carboxyl group can contain a compound having only one ethylenically unsaturated group. More specifically, the ethylenically unsaturated compound having a carboxyl group is acrylic acid, methacrylic acid, ω-carboxy-polycaprolactone (n≈2) monoacrylate, crotonic acid, cinnamic acid, 2-acryloyloxyethyl succinic acid. 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl phthalic acid, β-carboxyethyl acrylate, acryloyloxyethyl succinate, methacryloyloxyethyl succinate, 2-propenoic acid, 3- (2-carboxyethoxy) -3-oxypropyl ester, 2-acryloyloxyethyl tetrahydrophthalic acid, 2-methacryloyloxyethyl tetrahydrophthalic acid, 2-acryloyloxyethyl hexahydride One or more compounds selected from the group consisting of lophthalic acid and 2-methacryloyloxyethyl hexahydrophthalic acid can be contained. The ethylenically unsaturated compound having a carboxyl group can also contain a compound having a plurality of ethylenically unsaturated groups. More specifically, the ethylenically unsaturated compound having a carboxyl group can contain a compound obtained by reacting a difunctional acid anhydride with a polyfunctional (meth) acrylate having a hydroxyl group. These compounds are used individually by 1 type, or multiple types are used together. The polyfunctional (meth) acrylate having a hydroxyl group is, for example, pentaerythritol triacrylate, pentaerythritol trimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol pentamethacrylate. One or more compounds selected from the group consisting of:

  The ethylenically unsaturated compound having no carboxyl group for obtaining the second resin (b) may be any compound that can be copolymerized with the ethylenically unsaturated compound having a carboxyl group. The ethylenically unsaturated compound having no carboxyl group can contain both a compound having an aromatic ring and a compound having no aromatic ring.

  Examples of the compound having an aromatic ring include 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl-2-hydroxyethyl phthalate, 2- (meth) acryloyloxypropyl phthalate, and benzyl (meth). Acrylate, neopentyl glycol benzoate (meth) acrylate, paracumylphenoxyethylene glycol (meth) acrylate, EO-modified cresol (meth) acrylate, ethoxylated phenyl (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate (n = 2 to 2) 17), ECH-modified phenoxy (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxyhexaethylene glycol (meth) Acrylate, phenoxytetraethylene glycol (meth) acrylate, tribromophenyl (meth) acrylate, EO modified tribromophenyl (meth) acrylate, EO modified bisphenol A di (meth) acrylate, PO modified bisphenol A di (meth) acrylate, modified Bisphenol A di (meth) acrylate, EO modified bisphenol F di (meth) acrylate, ECH modified phthalic acid di (meth) acrylate, trimethylolpropane benzoate (meth) acrylate, EO modified phthalic acid (meth) acrylate, EO, PO modified One or more compounds selected from the group consisting of phthalic acid (meth) acrylate, vinyl carbazole, styrene, vinyl naphthalene, and vinyl biphenyl can be contained.

  The compound having no aromatic ring is, for example, a linear or branched aliphatic or alicyclic (however, the ring may partially have an unsaturated bond) (meth) acrylic acid ester, hydroxyalkyl One or more compounds selected from the group consisting of (meth) acrylates, alkoxyalkyl (meth) acrylates; and N-substituted maleimides can be contained. Examples of N-substituted maleimides include N-cyclohexylmaleimide. Compounds that do not have an aromatic ring include ethylene glycol in one molecule such as polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and pentaerythritol tri (meth) acrylate. You may contain the compound which has 2 or more of unsaturated unsaturated groups. These compounds are used individually by 1 type, or multiple types are used together. These compounds are preferable in that the hardness and oiliness of the film can be easily adjusted.

  As the ethylenically unsaturated compound having an epoxy group for obtaining the second resin (b), an appropriate polymer or prepolymer may be mentioned. Specific examples of the ethylenically unsaturated compound having an epoxy group include epoxycyclohexyl derivatives of acrylic acid or methacrylic acid; alicyclic epoxy derivatives of acrylate or methacrylate; β-methylglycidyl acrylate, β-methylglycidyl methacrylate, and the like. . These compounds are used individually by 1 type, or multiple types are used together. In particular, it is preferable to use glycidyl (meth) acrylate which is widely used and easily available.

  The component (A1) may contain a third resin (c). The third resin (c) is prepared by adding a part or all of hydroxyl groups in a polymer of ethylenically unsaturated monomers including an ethylenically unsaturated compound having a carboxyl group and an ethylenically unsaturated compound having a hydroxyl group. It is obtained by adding a compound having an ethylenically unsaturated group and an isocyanate group. The ethylenically unsaturated monomer may contain an ethylenically unsaturated compound having no carboxyl group and hydroxyl group, if necessary.

  The ethylenically unsaturated compound having a carboxyl group for obtaining the third resin (c) may be, for example, the same as the ethylenically unsaturated compound having a carboxyl group for obtaining the second resin (b).

  Specific examples of the ethylenically unsaturated compound having a hydroxyl group for obtaining the third resin (c) include hydroxyalkyl (meth) acrylate, hydroxybutyl vinyl ether, hydroxyethyl vinyl ether, and N-hydroxyethyl (meth) acrylamide. Etc. Examples of the hydroxyalkyl (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, cyclohexanedimethanol mono (meth) acrylate, 2- ( (Meth) acryloyloxyethyl-2-hydroxyethyl phthalate, caprolactone (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, Examples include dipentaerythritol penta (meth) acrylate.

  Specific examples of the compound having an ethylenically unsaturated group and an isocyanate group for obtaining the third resin (c) include 2-acryloyloxyethyl isocyanate (as a specific example, Showa Denko KK; product name “Karenz AOI”), 2-Methacryloyloxyethyl isocyanate (specific example Showa Denko KK; product name “Karenz MOI”), methacryloyloxyethoxyethyl isocyanate (specific example Showa Denko KK; product name “Karenz MOI-EG”), isocyanate block of Karenz MOI Body (as a specific example Showa Denko KK; product name “Karenz MOI-BM”), Karenz MOI isocyanate block (as a specific example Showa Denko KK; product name “Karenz MOI-BP”), and 1,1- (bis Acryloyloxymethyl) Le isocyanate) (Examples Showa Denko KK; product name "Karenz BEI") and the like.

  The weight average molecular weight of the entire component (A1) is preferably in the range of 800 to 100,000. Within this range, particularly excellent photosensitivity and resolution are imparted to the solder resist composition.

  The acid value of the entire component (A1) is preferably 30 mgKOH / g or more. In this case, good developability is imparted to the solder resist composition. The acid value is more preferably 60 mgKOH / g or more. The acid value of the entire component (A1) is preferably 160 mgKOH / g or less. In this case, the residual amount of carboxyl groups in the coating formed from the solder resist composition is reduced, and the coating has good electrical properties. In addition, electric corrosion resistance and water resistance are maintained. The acid value is more preferably 130 mgKOH / g or less.

(Carboxyl group-containing resin (A2))
The carboxyl group-containing resin (A) can contain a carboxyl group-containing resin (A2) (hereinafter also referred to as component (A2)) that has a carboxyl group and does not have a photopolymerizable functional group.

  (A2) A component contains the polymer of the ethylenically unsaturated monomer containing the ethylenically unsaturated compound which has a carboxyl group, for example. The ethylenically unsaturated monomer may further contain an ethylenically unsaturated compound having no carboxyl group.

  The ethylenically unsaturated compound having a carboxyl group can contain an appropriate polymer and prepolymer, for example, a compound having only one ethylenically unsaturated group. More specifically, the ethylenically unsaturated compound having a carboxyl group is acrylic acid, methacrylic acid, ω-carboxy-polycaprolactone (n≈2) monoacrylate, crotonic acid, cinnamic acid, 2-acryloyloxyethyl succinic acid. 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl phthalic acid, β-carboxyethyl acrylate, acryloyloxyethyl succinate, methacryloyloxyethyl succinate, 2-propenoic acid, 3- (2-carboxyethoxy) -3-oxypropyl ester, 2-acryloyloxyethyl tetrahydrophthalic acid, 2-methacryloyloxyethyl tetrahydrophthalic acid, 2-acryloyloxyethyl hexahydride One or more compounds selected from the group consisting of lophthalic acid and 2-methacryloyloxyethyl hexahydrophthalic acid can be contained. The ethylenically unsaturated compound having a carboxyl group can also contain a compound having a plurality of ethylenically unsaturated groups. More specifically, the ethylenically unsaturated compound having a carboxyl group can contain a compound obtained by reacting a difunctional acid anhydride with a polyfunctional (meth) acrylate having a hydroxyl group. These compounds are used individually by 1 type, or multiple types are used together. Examples of the polyfunctional (meth) acrylate having a hydroxyl group include pentaerythritol triacrylate, pentaerythritol trimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol pentamethacrylate. Selected from the group consisting of

  The ethylenically unsaturated compound which does not have a carboxyl group should just be a compound copolymerizable with the ethylenically unsaturated compound which has a carboxyl group. The ethylenically unsaturated compound having no carboxyl group can contain both a compound having an aromatic ring and a compound having no aromatic ring.

  Examples of the compound having an aromatic ring include 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxyethyl-2-hydroxyethyl phthalate, 2- (meth) acryloyloxypropyl phthalate, and benzyl (meth). Acrylate, neopentyl glycol benzoate (meth) acrylate, paracumylphenoxyethylene glycol (meth) acrylate, EO-modified cresol (meth) acrylate, ethoxylated phenyl (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate (n = 2 to 2) 17), ECH-modified phenoxy (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxyhexaethylene glycol (meth) Acrylate, phenoxytetraethylene glycol (meth) acrylate, tribromophenyl (meth) acrylate, EO modified tribromophenyl (meth) acrylate, EO modified bisphenol A di (meth) acrylate, PO modified bisphenol A di (meth) acrylate, modified Bisphenol A di (meth) acrylate, EO modified bisphenol F di (meth) acrylate, ECH modified phthalic acid di (meth) acrylate, trimethylolpropane benzoate (meth) acrylate, EO modified phthalic acid (meth) acrylate, EO, PO modified One or more compounds selected from the group consisting of phthalic acid (meth) acrylate, vinyl carbazole, styrene, vinyl naphthalene, and vinyl biphenyl can be contained.

  The compound having no aromatic ring is, for example, a linear or branched aliphatic or alicyclic (however, the ring may partially have an unsaturated bond) (meth) acrylic acid ester, hydroxyalkyl One or more compounds selected from the group consisting of (meth) acrylates, alkoxyalkyl (meth) acrylates, etc .; and N-substituted maleimides such as N-cyclohexylmaleimide can be contained. The compound having no aromatic ring may further contain a compound having two or more ethylenically unsaturated groups in one molecule. Examples of the compound having two or more ethylenically unsaturated groups in one molecule include polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meta ) Acrylate and the like. These compounds are used individually by 1 type, or multiple types are used together. These compounds are preferable in that the hardness and oiliness of the film can be easily adjusted.

  The type, ratio, and the like of the compound used to obtain the component (A2) are appropriately selected so that the acid value of the component (A2) becomes an appropriate value. The acid value of the component (A2) is preferably in the range of 20 to 180 mgKOH / g, more preferably in the range of 35 to 165 mgKOH / g.

[Photopolymerizable compound (B)]
The photopolymerizable compound (B) imparts photocurability to the solder resist composition. The photopolymerizable compound (B) contains one or more compounds selected from the group consisting of a photopolymerizable monomer and a photopolymerizable prepolymer.

  The photopolymerizable monomer has, for example, an ethylenically unsaturated group. The photopolymerizable monomer can contain, for example, one or more compounds selected from the group consisting of monofunctional (meth) acrylates; and polyfunctional (meth) acrylates. As monofunctional (meth) acrylate, 2-hydroxyethyl (meth) acrylate etc. are mentioned, for example. Examples of the polyfunctional (meth) acrylate include diethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol tetra (meth). Examples thereof include acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and ε-caprolactone-modified pentaerythritol hexaacrylate.

  It is also preferred that the photopolymerizable monomer contains a phosphorus-containing compound (phosphorus-containing photopolymerizable compound). In this case, the flame retardancy of the cured product of the solder resist composition is improved. Phosphorus-containing photopolymerizable compounds include, for example, 2-methacryloyloxyethyl acid phosphate (as specific examples, product names Light Ester P-1M and Light Ester P-2M manufactured by Kyoeisha Chemical Co., Ltd.), 2-acryloyloxyethyl acid phosphate ( As specific examples, product name light acrylate P-1A manufactured by Kyoeisha Chemical Co., Ltd., diphenyl-2-methacryloyloxyethyl phosphate (product name MR-260 manufactured by Daihachi Industry Co., Ltd.), and Showa Polymer Co., Ltd. HFA series (specifically, product names HFA-6003 and HFA-6003, which are addition reaction products of dipentaerystol hexaacrylate and HCA, product name HFA which is an addition reaction product of caprolactone-modified dipentaerystol hexaacrylate and HCA) -30 3, and it can contain one or more compounds selected from the group consisting of HFA-6127, etc.).

  Examples of the photopolymerizable prepolymer include a prepolymer obtained by polymerizing a photopolymerizable monomer and an ethylenically unsaturated group added thereto, and oligo (meth) acrylate prepolymers. Examples of the oligo (meth) acrylate prepolymers include epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) acrylate, alkyd resin (meth) acrylate, silicone resin (meth) acrylate, and spirane resin (meth). An acrylate etc. are mentioned.

[Photoinitiator (C)]
The photopolymerization initiator (C) is, for example, benzoin and its alkyl ethers; acetophenones; anthraquinones; thioxanthones; benzophenones; xanthones; compounds containing a nitrogen atom; α-hydroxyalkylphenones; One or more components selected from the group consisting of phenones; monoacylphosphine oxide photopolymerization initiators; acylphosphine photopolymerization initiators; and oxime ester photopolymerization initiators can be contained. Examples of acetophenones include acetophenone and benzyl dimethyl ketal. Examples of anthraquinones include 2-methylanthraquinone. Examples of the thioxanthones include 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diisopropylthioxanthone, and the like. Examples of benzophenones include benzophenone and 4-benzoyl-4′-methyldiphenyl sulfide. Examples of xanthones include 2,4-diisopropylxanthone. Examples of the compound containing a nitrogen atom include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanone. Examples of α-hydroxyalkylphenones include 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and 1- [4- (2-hydroxyethoxy). -Phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2 -Methyl-propan-1-one, phenylglyoxylic acid methyl ester and the like. Examples of α-aminoalkylphenones include 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholino Phenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone and the like. Examples of the monoacylphosphine oxide photopolymerization initiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,4,6-trimethylbenzoyl-ethyl-phenyl-phosphinate, and the like. Examples of the acylphosphine photopolymerization initiator include bis- (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis- (2,6-dichlorobenzoyl) phenylphosphine oxide, and bis- (2,6- Dichlorobenzoyl) -2,5-dimethylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -4-propylphenylphosphine 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-dimethyl Phenylphosphine oxide (2,5,6-trimethylbenzoyl) -2,4,4-trimethylpentyl phosphine oxide and the like. Examples of the oxime ester photopolymerization initiator include 1,2-octanedione, 1- [4- (phenylthio)-, 2- (О-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (0-acetyloxime) and the like. The photopolymerization initiator (C) includes two or more components selected from the group consisting of α-hydroxyalkylphenones, α-aminoalkylphenones, thioxanthones, and acylphosphine oxide photopolymerization initiators. It is particularly preferable.

[Crystalline epoxy resin (D)]
The crystalline epoxy resin (D) facilitates the formation of bubbles in the film formed from the solder resist composition.

  The crystalline epoxy resin (D) has a melting point of 130 ° C or higher, preferably 138 ° C to 230 ° C.

  The crystalline epoxy resin (D) can contain one or more compounds selected from the group consisting of monomers, prepolymers and polymers having an epoxy group and crystallinity. Such compounds are commercially available and are readily available. For example, crystalline epoxy resin (D) is 1,3,5-tris (2,3-epoxypropyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione (high Melting point type), product name YDC-1312 (hydroquinone type crystalline epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., product name GTR-1800 (tetrakisphenol ethane type crystalline epoxy resin) manufactured by Nippon Kayaku Co., Ltd. One or more compounds can be included.

[Blue dispersant (E)]
The blue dispersant (E) is not classified as a colorant, but can impart a color to the coating. When the solder resist composition does not contain a colorant (F), the coating becomes blue due to the blue dispersant (E). Further, the blue dispersant (E) improves the dispersibility of the crystalline epoxy resin (D). Therefore, it becomes easy to generate air bubbles more uniformly in the film formed from the solder resist composition than when the blue dispersant (E) is not contained. Thereby, the film which has the marking excellent in visibility can be produced.

  The blue dispersant (E) can contain a copper phthalocyanine sulfonate derivative. Specific examples of the copper phthalocyanine sulfonate derivative include product names Solsperse 5000, Solsperse 12000, Solsperse 22000 (all of which are copper phthalocyanine sulfonate derivatives) manufactured by Lubrizol.

[Colorant (F)]
The solder resist composition of this embodiment can contain a colorant (F). Thereby, the color of the film can be adjusted, and in particular, the visibility of the marking can be further improved when the film is formed on a printed wiring board having a copper wiring. The colorant (F) can contain both pigments and dyes.

  The colorant (F) may be appropriately selected according to the color of the insulating layer of the printed wiring board. For example, a blue colorant, a black colorant, a red colorant, a green colorant, a yellow colorant, a purple colorant, An orange colorant, a brown colorant and the like can be contained.

  In particular, the colorant (F) preferably contains at least one of a black colorant and a red colorant. Thereby, when forming a film on a printed wiring board provided with copper wiring, the visibility of the marking in a film becomes high especially.

  The black colorant can contain a perylene-based black colorant. The perylene-based black colorant can contain, for example, one or more components selected from the group consisting of a color index (CI) pigment black 31 and a color index (CI) pigment black 32. . In addition to the above components, the perylene-based black colorant has no color index number, but “Lumogen Black FK 4280” and “Lumogen Black FK” manufactured by BASF are known as perylene-based near-infrared transmitting black colorants. At least one of “4281” can be contained.

  The red colorant can contain, for example, one or more components selected from the group consisting of an anthraquinone red pigment, an azo red pigment, a lake red pigment, a quinacridone red pigment, and a diketopyrrole red pigment. Anthraquinone red pigments include, for example, Color Index (CI) Pigment Red 83, Color Index (CI) Pigment Red 168, Color Index (CI) Pigment Red 177, Color Index (C.I). .) Pigment Red 216 and the like. When the red colorant is an anthraquinone-based red colorant, it is particularly easy to ensure the concealability of the conductor wiring by the film formed from the solder resist composition. Moreover, it is excellent in dispersibility and weather resistance.

  The blue colorant can contain a colorant such as a phthalocyanine blue colorant and an anthraquinone blue colorant.

  The green colorant contains, for example, one or more colorants selected from the group consisting of phthalocyanine green colorants, anthraquinone green colorants, perylene green colorants, and metal-substituted or unsubstituted phthalocyanine compounds. Can do. More specific examples of the green colorant include pigment green 7; pigment green 36.

[Other ingredients]
The solder resist composition may contain a crystalline epoxy resin having a melting point of less than 130 ° C. The crystalline epoxy resin having a melting point of less than 130 ° C. is, for example, product name YSLV-80XY (bisphenol type crystalline epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., product name YSLV-120TE (thioether type crystalline epoxy manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) Resin), bisphenolfluorene type crystalline epoxy resin, product name YX-4000 (biphenyl type crystalline epoxy resin) manufactured by Mitsubishi Chemical Corporation, and 1,3,5-tris (2,3-epoxypropyl) -1,3 , 5-triazine-2,4,6 (1H, 3H, 5H) -trione (low melting point type) can be contained.

  The solder resist composition may contain an amorphous epoxy resin. The amorphous epoxy resin includes, for example, an amorphous cresol novolac type epoxy resin (specifically, product name EPICLON N-695 manufactured by DIC Corporation), and an amorphous phenol novolac type epoxy resin (specifically, DIC Corporation). Product name EPICLON N-775), amorphous bisphenol A novolak type epoxy resin (specifically, product name EPICLON N-865 manufactured by DIC Corporation), amorphous bisphenol A type epoxy resin (specifically Mitsubishi Chemical) Product name jER1001), amorphous bisphenol F epoxy resin (specifically, product name jER4004P manufactured by Mitsubishi Chemical Corporation), amorphous bisphenol S type epoxy resin (specifically, product name manufactured by DIC Corporation) EPICLON EXA-1514), amorphous Sphenol AD type epoxy resin, amorphous hydrogenated bisphenol A type epoxy resin, amorphous biphenyl novolac type epoxy resin, and amorphous special bifunctional type epoxy resin (specifically, manufactured by Mitsubishi Chemical Corporation) Product names EPICLON TSR-960, EPICLON TER-601, EPICLON TSR-250-80BX, EPICLON 1650-75MPX, EPICLON EXA-4850, EPICLON EXICA4816, manufactured by DIC Corporation EXA-4822, and EPICLON EXA-9726; product name YSLV-120T manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., and other than the above-mentioned amorphous bisphenol-based epoxy resins It is the may contain one or more compounds.

  The solder resist composition may contain an organic solvent. The organic solvent is used for the purpose of liquefaction or varnishing of the solder resist composition, viscosity adjustment, application property adjustment, film formation property adjustment, and the like.

  Organic solvents include, for example, linear, branched, secondary or polyhydric alcohols; ketones; aromatic hydrocarbons; petroleum-based aromatic mixed solvents; cellosolves; carbitols; propylene glycol alkyl ethers; One or more compounds selected from the group consisting of glycol alkyl ethers; acetate esters; and dialkyl glycol ethers can be contained. Examples of linear, branched, secondary or polyhydric alcohols include ethanol, propyl alcohol, isopropyl alcohol, hexanol, and ethylene glycol. Examples of ketones include methyl ethyl ketone and cyclohexanone. Examples of aromatic hydrocarbons include toluene, xylene and the like. Examples of the petroleum-based aromatic solvent mixture include the Swazol series (manufactured by Maruzen Petrochemical Co., Ltd.) and the Solvesso series (manufactured by Exxon Chemical Co., Ltd.). Examples of cellosolves include cellosolve and butyl cellosolve. Examples of carbitols include carbitol and butyl carbitol. Examples of propylene glycol alkyl ethers include propylene glycol methyl ether. Examples of polypropylene glycol alkyl ethers include dipropylene glycol methyl ether. Examples of acetates include ethyl acetate, butyl acetate, cellosolve acetate, carbitol acetate and the like.

  The ratio of the organic solvent in the solder resist composition is adjusted so that when the coating film formed from the solder resist composition is dried, the organic solvent is volatilized quickly, that is, the organic solvent does not remain in the dry film. It is preferred that In particular, the organic solvent is preferably in the range of 5 to 99.5% by mass and more preferably in the range of 15 to 80% by mass with respect to the entire solder resist composition. In addition, since the suitable ratio of an organic solvent changes with application methods etc., it is preferable that a ratio is suitably adjusted according to the application method.

  Unless it deviates from the main point of this invention, the soldering resist composition may further contain components other than the said component.

  For example, the solder resist composition includes a blocked isocyanate; an amino resin; various other thermosetting resins; an ultraviolet curable epoxy (meth) acrylate; a resin obtained by adding (meth) acrylic acid to an epoxy resin; You may contain 1 or more types of resin selected from the group which consists of a high molecular compound. Examples of the blocked isocyanate include tolylene diisocyanate-based, morpholine diisocyanate-based, isophorone diisocyanate-based, hexamethylene diisocyanate-based blocked isocyanate blocked with caprolactam, oxime, malonic acid ester and the like. Examples of amino resins include melamine resins, n-butylated melamine resins, isobutylated melamine resins, butylated urea resins, butylated melamine urea cocondensation resins, benzoguanamine-based cocondensation resins, and the like. Examples of the epoxy resin include bisphenol A type, phenol novolac type, cresol novolac type, and alicyclic type epoxy resin. Examples of the polymer compound include diallyl phthalate resin, phenoxy resin, urethane resin, and fluororesin.

  When the solder resist composition contains an epoxy compound, the solder resist composition may further contain a curing agent for curing the epoxy compound. The curing agent may contain, for example, one or more components selected from the group consisting of an imidazole derivative; an amine compound; a hydrazine compound; a phosphorus compound; an acid anhydride; a phenol; a mercaptan; a Lewis acid amine complex; it can. Examples of imidazole derivatives include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- ( 2-cyanoethyl) -2-ethyl-4-methylimidazole and the like. Examples of amine compounds include dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N-dimethylbenzylamine, 4-methyl-N, N-dimethylbenzyl. An amine etc. are mentioned. Examples of the hydrazine compound include adipic acid hydrazide and sebacic acid hydrazide. Examples of the phosphorus compound include triphenylphosphine. Examples of commercially available products of these components include 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ (both trade names of imidazole compounds) manufactured by Shikoku Kasei Co., Ltd., U-CAT3503N, U manufactured by San Apro Co., Ltd. -CAT3502T (all are trade names of blocked isocyanate compounds of dimethylamine), DBU, DBN, U-CATSA102, U-CAT5002 (all are bicyclic amidine compounds and salts thereof).

  The solder resist composition may contain an adhesion promoter. Examples of the adhesion-imparting agent include guanamine, acetoguanamine, benzoguanamine, melamine, and S-triazine derivatives. Examples of S-triazine derivatives include 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-4,6-diamino-S-triazine, 2-vinyl-4,6-diamino-S. -Triazine-isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxyethyl-S-triazine-isocyanuric acid adduct, and the like.

  The solder resist composition comprises a curing accelerator; a copolymer; a leveling agent; an adhesion-imparting agent; a thixotropic agent; a polymerization inhibitor; an antihalation agent; a flame retardant; an antifoaming agent; One or more components selected from the group consisting of a dispersant; and an inorganic filler may be contained. Examples of the copolymer include silicone and acrylate. Examples of the adhesion imparting agent include a silane coupling agent. Examples of the inorganic filler include barium sulfate, crystalline silica, nano silica, carbon nanotube, talc, bentonite, aluminum hydroxide, magnesium hydroxide, magnesium oxide, and calcium carbonate.

  The solder resist composition may further contain a known photopolymerization accelerator, sensitizer and the like. For example, the solder resist composition may contain p-dimethylbenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamyl ester, 2-dimethylaminoethylbenzoate and the like.

[Blend amount and preparation method of each component contained in solder resist composition]
The amount of the components in the solder resist composition is appropriately adjusted so that the solder resist composition has photocurability and can be developed with an alkaline solution.

  The content ratio of the carboxyl group-containing resin (A) is preferably in the range of 20 to 65% by mass with respect to the solid content of the solder resist composition, more preferably in the range of 25 to 55% by mass, 30 More preferably, it is in the range of ˜50 mass%. The solid content here means the total amount of all components excluding components such as a solvent that volatilizes in the process of forming a film from the solder resist composition.

  The content of the photopolymerizable compound (B) is preferably in the range of 5 to 60% by mass, and in the range of 10 to 50% by mass with respect to the carboxyl group-containing resin (A) contained in the solder resist composition. It is more preferable if it is in the range of 15 to 40% by mass.

  The content of the photopolymerization initiator (C) is preferably in the range of 1 to 50% by mass, and in the range of 3 to 40% by mass with respect to the carboxyl group-containing resin (A) contained in the solder resist composition. It is more preferable if it is in the range, and it is more preferable if it is in the range of 5 to 25% by mass.

  The content of the crystalline epoxy resin (D) is preferably in the range of 15 to 200% by mass with respect to the carboxyl group-containing resin (A) contained in the solder resist composition, and in the range of 20 to 100% by mass. It is more preferable if it is within the range, more preferably within the range of 25 to 80% by mass, and particularly preferably within the range of 30 to 60% by mass.

  The content of the blue dispersant (E) is preferably 0.1 to 10% by mass, and 0.5 to 5% by mass with respect to the carboxyl group-containing resin (A) contained in the solder resist composition. It is more preferable, and it is still more preferable that it is 1-3 mass%. If the content ratio of the blue dispersant (E) is within the above range, the adhesion between the printed wiring board 1 and the coating 3 described later can be further increased, and further, the first region 33 and the second region described later are provided. The boundary with the region 34 can be made clearer. In particular, when the content of the blue dispersant (E) is 5% by mass or less, the adhesion between the printed wiring board 1 and the coating 3 can be particularly increased. If the content of the blue dispersant (E) is 3% by mass or less, the adhesion between the printed wiring board 1 and the coating 3 can be particularly increased, and the first region 33 and the second region 34 The boundaries can be made particularly clear.

  When a soldering resist composition contains a coloring agent (F), the content rate of a coloring agent (F) is 0.01-5 mass% with respect to carboxyl group containing resin (A) contained in a soldering resist composition. It is preferably within the range, and more preferably within the range of 0.05 to 1% by mass. If the content rate of a coloring agent (F) is in the said range, the visibility of the marking in a film can be made higher. The content of the black colorant is preferably in the range of 0.01 to 5% by mass, and in the range of 0.05 to 1% by mass with respect to the carboxyl group-containing resin (A) contained in the solder resist composition. If it is in, it is more preferable. The content ratio of the red colorant is preferably in the range of 0.01 to 5% by mass, and in the range of 0.05 to 1% by mass with respect to the carboxyl group-containing resin (A) contained in the solder resist composition. If it is in, it is more preferable.

  The raw material of the solder resist composition as described above is blended, and the solder resist composition can be prepared by kneading by a known kneading method using, for example, a three roll, ball mill, sand mill or the like. By roll kneading the solder resist composition, good dispersibility of the crystalline epoxy resin (D) and the inorganic pigment can be obtained, and visibility can be improved.

  In consideration of storage stability and the like, the first agent may be prepared by mixing a part of the raw material of the solder resist composition, and the second agent may be prepared by mixing the remainder of the raw material. For example, the first agent is prepared by previously mixing and dispersing the photopolymerizable compound (B), a part of the organic solvent, and the crystalline epoxy resin (D) among the raw materials of the solder resist composition. The second agent may be prepared by mixing and dispersing the remainder of the raw material of the solder resist composition. In this case, a solder resist composition can be prepared by mixing the necessary amount of the first agent and the second agent in a timely manner.

{Coating and coated printed wiring board}
As shown in FIG. 3, the coated printed wiring board includes a printed wiring board 1 and a coating 3 formed from a solder resist composition. The printed wiring board 1 includes an insulating layer and copper wiring on the insulating layer. The coating 3 covers the insulating layer and the wiring.

  The color of an insulating layer is not specifically limited, For example, it is preferable that they are yellow, yellowish green, white, cream color, brown, orange, green, or black.

  As the printed wiring board 1, for example, a paper phenol substrate (FR-1, FR-2), a paper epoxy substrate (FR-3, ivory color), a glass epoxy substrate (glass cloth epoxy) (FR-4, FR-5). ), Glass mat polyester substrate (FR-6), glass composite substrate (glass paper epoxy) (CEM-1), glass composite substrate (glass base epoxy) (CEM-3), glass polyimide substrate, polyimide film, fluororesin (Teflon (registered trademark)) substrate, metal substrate (mainly aluminum), ceramic substrate and the like.

  The printed wiring board 1 preferably includes at least one of a rigid material and a flexible material.

  As shown in FIG. 3, the coating 3 includes a first region 33 and a second region 34 having a higher light transmittance than the first region 33. The first region 33 contains bubbles. The second region 34 does not contain bubbles or the ratio of bubbles is lower than that of the first region 33. For this reason, the first region 33 is less light transmissive than the second region 34.

  When the coating 3 is observed from the outside, light scattering due to bubbles occurs in the first region 33, resulting in a whitish color tone, and the color of the printed wiring board 1 as a base is difficult to see through. On the other hand, in the second region 34, the color of the printed wiring board 1 is easily seen through because there is little or no light scattering due to bubbles. Therefore, the appearance color of the second region 34 is a color in which the color of the second region 34 itself and the color of the printed wiring board 1 are mixed. That is, there is a difference in appearance between the first region 33 and the second region 34. In the present embodiment, since the coating 3 contains the blue dispersant (E), the appearance color of the second region 34 (that is, the color of the second region 34 itself and the color of the printed wiring board 1 is mixed). And the color tone of the appearance color of the first region 33 are greatly different. For this reason, marking with high visibility can be obtained using the first region 33 and the second region 34. When the coating 3 further contains a colorant (F), the difference in color tone between the appearance color of the first region 33 and the appearance color of the second region 34 is further increased, and the visibility of the marking is further improved.

  By forming the first region 33 and the second region 34 in the coating 3 in this way, a highly visible marking can be easily formed on the coating 3. For example, the first region 33 is formed into an appropriate figure, character, or the like, so that the marking by the first region 33 is formed. Moreover, the marking by the 2nd area | region 34 may be formed by forming the 2nd area | region 34 in shapes, such as a suitable figure and a character. For this reason, marking can be performed simultaneously with the formation of the coating 3.

  The thickness of the coating 3 is, for example, in the range of 5 to 60 μm. Thus, since the coating 3 can make the thickness of the whole coating thinner than the conventional two-layer coating, for example, when producing the coated printed wiring board 1, exposure (UV light) is applied from the surface layer of the coating 3. It is easy to reach the deep part sufficiently, and the adhesion between the printed wiring board 1 and the coating 3 can be improved. Further, in this thickness range, the difference between the appearance color of the first region 33 and the appearance color of the second region 34 is clearly visible.

  The ratio of bubbles in the first region 33 is preferably in the range of 3 to 70%, and more preferably in the range of 5 to 60%. Moreover, it is preferable that the ratio of the value of the bubble ratio in the second region 34 to the value of the bubble ratio in the first region 33 is in the range of 0 to 5%.

The ratio of the bubbles is the area ratio of bubbles having a major axis of 0.5 μm or more on the surface appearing by polishing the surface of the coating 3 (that is, the cross section of the coating 3 along the surface of the coating 3). This area ratio is derived, for example, based on the area of bubbles having a major axis of 0.5 μm or more on the surface having a surface area of 20 μm ^{2 in} the coating film.

  These ratios are controlled by appropriately adjusting the exposure amount of the first portion 21 and the exposure amount of the second portion 22 at the time of exposure in the manufacturing method of the coated printed wiring board including the coating film and the coating film described later. sell.

{Film and method for producing printed wiring board provided with film}
The manufacturing method of a printed wiring board provided with the film and film of this embodiment is demonstrated with reference to FIGS.

The method for producing the coating of the present embodiment is as follows:
<a> forming the coating film 2 comprising the solder resist composition of the present embodiment,
<B> The process of exposing the coating film 2 and <c> The process of forming the coating film 3 by heating the coating film 2 after exposure.

  In the step <b>, the first portion 21 in the coating film 2 is irradiated with light, and the second portion 22 different from the first portion 21 in the coating film 2 is not irradiated with light. Light is irradiated so that the exposure amount is lower than that of the first portion 21.

  In the step <c>, by generating bubbles in the first portion 21 by heating, the first region 33 containing bubbles in the coating 3 and the ratio of the bubbles not containing bubbles are first. The second region 34 lower than the region 33 is formed.

  The coating film production method described above may not include the step of developing the coating film 2 with a developer after the step <b> and before the step of <c>, and developing the coating film 2 with the developer. The process of carrying out may be included.

The method for producing the coated printed wiring board of the present embodiment is as follows:
A method for producing a coated printed wiring board, comprising:
<D> a step of forming the coating film 2 by disposing the solder resist composition of the present embodiment on the printed wiring board 5 so as to cover the insulating layer and the wiring;
<E> a step of exposing the coating film 2;
<F> A step of developing the exposed coating film 2 with an alkaline developer, and <g> a step of forming the coating film 3 by heating the coated film 2 after development.

  In the step <e>, the first portion 21 in the coating film 2 is irradiated with light, and the second portion 22 different from the first portion 21 in the coating film 2 is exposed more than the first portion 21. Light is irradiated so that the amount is low.

  In the step <g>, by generating bubbles in the first portion 21 by heating, the first region 33 containing bubbles in the coating 3 and the ratio of the bubbles not containing bubbles are first. The second region 34 lower than the region 33 is formed.

[Process <a>, <d>]
In the steps <a> and <d>, the solder resist composition of the present embodiment is applied onto the printed wiring board 1, and the coating film 2 made of the solder resist composition of the present embodiment is applied as shown in FIG. Form. At this time, in the step <d>, the coating film 2 is formed by disposing the solder resist composition of the present embodiment on the printed wiring board so as to cover the insulating layer and the wiring.

  The method for applying the solder resist composition is selected from the group consisting of known methods such as dipping, spraying, spin coating, roll coating, curtain coating, and screen printing.

  As needed, in order to volatilize the organic solvent in a soldering resist composition, the coating film 2 is heated (preliminary drying). The heating temperature in this case is preferably a temperature lower than the melting point of the crystalline epoxy resin (D) in the solder resist composition, and in particular 30 from the melting point of the crystalline epoxy resin (D) in the solder resist composition. It is preferable that the temperature is lower than the temperature reduced by ° C. This heating temperature is, for example, in the range of 60 to 100 ° C.

  In forming the coating film 2 on the printed wiring board 1, a dry film is formed by applying a solder resist composition on an appropriate support in advance and then drying. The drying condition is preferably a temperature lower than the melting point of the crystalline epoxy resin (D) in the solder resist composition, particularly 30 ° C. lower than the melting point of the crystalline epoxy resin (D) in the solder resist composition. It is preferable that the temperature is lower than the temperature. This heating temperature is, for example, in the range of 60 to 100 ° C. After the dry film is overlaid on the printed wiring board 1, the dry film may be transferred onto the printed wiring board 1 by applying pressure to the dry film and the printed wiring board 1 (dry film method). This dry film becomes the coating film 2. In this case, preliminary drying may be omitted.

[Process <b>, <e>]
In steps <b> and <e>, as shown in FIG. 2, the coating film 2 is exposed by irradiating the coating film 2 with light through a mask 4. Thereby, photocuring reaction advances efficiently from the surface layer of the coating film 2 to the deep part. In particular, since the coating film 2 is a single layer, the entire film thickness is thinner than the conventional two-layer coating film, and the coating film 2 is sufficiently cured from the surface layer to the deep part.

  At this time, the first portion 21 in the coating film 2 is irradiated with light so that the second portion 22 different from the first portion 21 in the coating film 2 has a lower exposure amount than the first portion 21. Irradiate light. Further, the third portion 23 different from the first portion 21 and the second portion 22 in the coating film 2 is not irradiated with light. When light is thus irradiated, the photopolymerization reaction of the photopolymerizable compound proceeds in the first portion 21 of the coating film 2. On the other hand, in the second portion 22, although the degree is lower than that of the first portion 21, the photopolymerization reaction of the photopolymerizable compound proceeds. In the third portion 23, the photopolymerization reaction of the photopolymerizable compound does not proceed.

  The exposure amount in the first portion 21 may be uniform, or a plurality of portions having different exposure amounts may exist in the first portion 21. Moreover, when irradiating light to the 2nd part 22, the exposure amount in the 2nd part 22 may be uniform, and even if the several part from which the exposure amount differs in the 2nd part 22 exists, Good.

  The light for exposure is selected so that the photopolymerization reaction of the photopolymerizable compound in the solder resist composition proceeds upon irradiation with this light. For example, ultraviolet light, visible light, or near infrared light is selected as light for exposure. When ultraviolet light is selected, the ultraviolet light source is selected from the group consisting of, for example, chemical lamps, low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, ultra high pressure mercury lamps, xenon lamps and metal halide lamps.

  The mask 4 includes three types of portions having different degrees of light transmission. For example, the mask 4 includes a light transmissive portion (hereinafter referred to as a transmissive portion 41), a light transmissive portion lower than the transmissive portion 41 (hereinafter referred to as a low transmissive portion 42), and a light transmissive property. A portion (hereinafter referred to as a non-permeable portion 43).

  When the coating film 2 is exposed through the mask 4, light is irradiated to a portion (first portion 21) corresponding to the transmissive portion 41 in the coating film 2. The portion (second portion 22) corresponding to the low-permeability portion 42 in the coating film 2 is irradiated with light at an exposure amount lower than that of the first portion 21. The portion (third portion 23) corresponding to the non-permeable portion 43 in the coating film 2 is not irradiated with light. The first portion 21 is a portion irradiated with light at the time of exposure, the second portion 22 is a portion irradiated with light at an exposure amount lower than that of the first portion 21 at the time of exposure, It can also be said that the third portion 23 is a portion that is not irradiated with light during exposure. The mask 4 is designed so that the first portion 21, the second portion 22, and the third portion 23 are located at predetermined positions in the coating film 2.

  The ratio of the exposure amount of the second portion 22 to the exposure amount of the first portion 21 is, for example, in the range of 1 to 75%, and particularly preferably in the range of 1.2 to 60%.

The exposure amount of the first portion 21 is, for example, in the range of 100 to 5000 mJ / cm ² , and the exposure amount of the second portion 22 is, for example, in the range of ^{20 to} 500 mJ / cm ² .

  In the present embodiment, the mask 4 is used. However, if the exposure amounts in the first portion 21, the second portion 22, and the third portion 23 can be controlled to desired values, the mask 4 as described above is used. May not be used. For example, first, the coating film 2 is irradiated with light through a mask (first mask) that shields the third portion 23 and does not shield the first portion 21 and the second portion 22. Subsequently, a mask (second mask) that shields the second portion 22 and does not shield the first portion 21 is superimposed on the first mask, and through the first mask and the second mask, Further, light may be irradiated. Even in this case, the first portion 21 is irradiated with light, the second portion 22 is irradiated with light at a lower exposure amount than the first portion 21, and the third portion 23 is irradiated with light. Not irradiated.

  From the time when the coating film 2 made of the solder resist composition is formed on the printed wiring board 1 to the time when the exposure of the coating film 2 is completed, the temperature of the coating film 2 is changed to that of the crystalline epoxy resin (D). It is preferable to maintain the temperature lower than the melting point. In this case, the ratio of bubbles in the first region 33 is higher. For this reason, the difference in appearance color between the first region 33 and the second region 34 becomes more prominent. This is because when the crystalline epoxy resin (D) melts in the first portion 21 before the photopolymerizable compound in the first portion 21 is polymerized, the crystalline epoxy resin (D Therefore, even if the first portion 21 is heated after the coating film 2 is exposed, the first portion 21 is less likely to be deformed. More preferably, the temperature of the coating film 2 is determined from the melting point of the crystalline epoxy resin (D) from the time when the solder resist composition is disposed on the printed wiring board 1 until the time when the exposure of the coating film 2 is completed. Maintain a temperature lower than the temperature reduced by 30 ° C.

[Process <f>]
In step <f>, the exposed coating film 2 is developed with an alkaline developer. Thereby, the third portion 23 of the coating film 2, which is a portion corresponding to the non-permeable portion 43 in the coating film 2, is removed from the printed wiring board 1. The first portion 21 and the second portion 22 of the coating film 2 remain on the printed wiring board 1.

  Specific examples of the alkaline developer include sodium carbonate aqueous solution, potassium carbonate aqueous solution, ammonium carbonate aqueous solution, sodium hydrogen carbonate aqueous solution, potassium hydrogen carbonate aqueous solution, ammonium hydrogen carbonate aqueous solution, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, ammonium hydroxide aqueous solution, Examples include tetramethylammonium hydroxide aqueous solution and lithium hydroxide aqueous solution. An organic amine or the like can also be used as the developer. Examples of the organic amine include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine and the like. The solvent in the alkaline developer may be water alone or a mixture of water and a hydrophilic organic solvent such as lower alcohols.

[Process <c>, <g>]
In steps <c> and <g>, the coating film 3 is formed by heating the coating film 2 after exposure on the printed wiring board 1. When the coating film 2 is heated in this way, bubbles are formed in the first portion 21. In particular, since the solder resist composition of the present embodiment contains a blue dispersant (E) and the dispersibility of the crystalline epoxy resin (D) is high, the solder resist composition is more first than the case of not containing the blue dispersant (E). Bubbles are easily formed in the portion 21. On the other hand, bubbles are not formed in the second portion 22 even when heated, or bubbles are formed, but the ratio of the bubbles is lower than that of the first portion 21. For this reason, the light transmittance of the first region 33 in the coating 3 is lower than that of the second region 34. Further, light scattering is more likely to occur in the first region 33 than in the second region 34. Moreover, when the coating film 2 is heated in this way, when the solder resist composition contains an epoxy compound, a thermosetting reaction of the epoxy compound proceeds.

  The reason why bubbles are formed in the first portion 21 in this way is assumed to be due to the following reason.

  Since the first portion 21 is irradiated with light when the coating film 2 is exposed, the first portion 21 contains a polymer generated by a photopolymerization reaction of a photopolymerizable compound. When the coating film 2 is heated in this state, the crystalline epoxy resin (D) in the coating film 2 is melted so that the coating film 2 tends to deform, but the first portion 21 contains a polymer. Therefore, it hardly deforms following the melting of the crystalline epoxy resin (D). For this reason, it is considered that bubbles are generated in the first portion 21. On the other hand, the 2nd part 22 does not contain the polymer of a photopolymerizable compound, or the ratio of this polymer is lower than a 1st part. For this reason, when the coating film 2 is heated, the second portion 22 is more easily deformed following the melting of the crystalline epoxy resin (D) than the first portion 21. For this reason, it is considered that bubbles are not generated in the second portion 22, or the ratio of bubbles in the second portion 22 is lower than that of the first portion 21.

  The heating temperature of the coating film 2 preferably satisfies the relationship of Th ≧ Tm−30, more preferably satisfies the relationship of Tm + 100 ≧ Th ≧ Tm−30. When the heating temperature of the coating film 2 is within the above range, deterioration of components in the solder resist composition due to heat can be suppressed. In this formula, Th (° C.) is the heating temperature of the coating film 2, and Tm (° C.) is the melting point of the crystalline epoxy resin (D). The heating temperature is, for example, in the range of 100 to 200 ° C. The heating time is in the range of 10 minutes to 5 hours.

  In addition, even if the heating temperature at the time of heating the coating film 2 is lower than the melting point of the crystalline epoxy resin (D), if it is equal to or higher than the temperature obtained by subtracting 30 ° C. from the melting point of the crystalline epoxy resin (D), Bubbles are generated in the first portion 21. The reason is not clearly understood, but the melting point drop (freezing point depression) of the crystalline epoxy resin (D) occurs when another compound is mixed into the crystalline epoxy resin (D) in the coating film 2. This is presumed to be one of the reasons.

  After the coating film 2 is heated, the entire coating film 2 may be irradiated with light. In this case, the photopolymerization reaction of the photopolymerizable compound remaining unreacted in the coating film 2 proceeds.

  Hereinafter, the present invention will be specifically described by way of examples.

[Preparation of carboxyl group-containing resin solution]
In a four-necked flask equipped with a reflux condenser, a thermometer, an air blowing tube and a stirrer, 203 parts by mass of a cresol novolac type epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., product name YDCN-700-5, epoxy equivalent 203), A mixture was prepared by adding 103 parts by mass of diethylene glycol monoethyl ether acetate, 0.2 parts by mass of methylhydroquinone, 72 parts by mass of acrylic acid, and 1.5 parts by mass of triphenylphosphine. This mixture was heated under the conditions of a heating temperature of 110 ° C. and a heating time of 10 hours, thereby allowing the addition reaction to proceed. Subsequently, 60.8 parts by mass of tetrahydrophthalic anhydride and 78.9 parts by mass of diethylene glycol monoethyl ether acetate were added to the mixture, and the mixture was further heated under the conditions of a heating temperature of 80 ° C. and a heating time of 3 hours. This obtained the 65 mass% solution (carboxyl group containing resin solution A) of carboxyl group containing resin.

[material]
In addition to the carboxyl group-containing resin solution A, the following raw materials were prepared.
Crystalline epoxy compound A: 1,3,5-tris (2,3-epoxypropyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione (high melting point type) , Melting point 150-158 ° C
Crystalline epoxy compound B: Hydroquinone type crystalline epoxy resin, product name YDC-1312 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., melting point 138-145 ° C.
Crystalline epoxy compound C: Bisphenol type crystalline epoxy resin, product name YSLV-80XY, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., melting point 75-85 ° C.
-Amorphous epoxy compound solution: Amorphous cresol novolac type epoxy resin, a solution obtained by dissolving DIC Corporation product name EPICLON N-695 at a solid content of 70% in diethylene glycol monoethyl ether acetate-Photopolymerizable compound: Di Pentaerythritol hexaacrylate (product name KAYARAD DPHA manufactured by Nippon Kayaku Co., Ltd.)
Photopolymerization initiator A: Product name Irgacure TPO manufactured by BASF
Photopolymerization initiator B: Product name Irgacure 184 manufactured by BASF
-Barium sulfate: Product name Variace B30 manufactured by Sakai Chemical Industry Co., Ltd.
・ Fine silica: Product name Leoroseal MT-10C manufactured by Tokuyama Corporation
・ Melamine: Product name Melamine HM manufactured by Nissan Chemical Industries, Ltd.
-Antifoaming agent: Product name KS-66 manufactured by Shin-Etsu Chemical Co., Ltd.
Solvent: Diethylene glycol monoethyl ether acetate Blue dispersant: Copper phthalocyanine sulfonate derivative, product name Solsperse 5000 manufactured by Lubrizol
Blue colorant: phthalocyanine blue, product name cyanine blue 4940 manufactured by Dainichi Seika Kogyo Co., Ltd.
Black colorant: Perylene-based black pigment, product name Paliogen Black S 0084 manufactured by BASF
Red colorant: Anthraquinone red pigment, product name Palogen Red L 4045 manufactured by BASF
Green colorant: Product name Lionol Green 6Y-501 manufactured by Toyo Ink Manufacturing Co., Ltd.

[Examples and Comparative Examples]
The raw materials shown in Tables 1 and 2 below were mixed and dispersed by a three roll to prepare a solder resist composition. The crystalline epoxy compounds A and B were previously pulverized by a jet mill or a mortar so that the average particle size was 20 μm or less.

In Examples 1 to 12 and Comparative Examples 1 to 4, the following printed wiring boards were prepared, and by applying the obtained solder resist composition on each printed wiring board by a screen printing method, the insulating layer and A one-layer coating film was formed covering the copper wiring on the insulating layer.
・ Printed wiring board (glass epoxy board) with copper wiring with a thickness of 35μm, whose insulating layer surface is yellow in color
・ Printed wiring board (glass epoxy board) with copper wiring with a thickness of 35μm, and the color of the insulating layer surface is yellow-green
・ A printed wiring board (glass composite board) with copper wiring with a thickness of 35 μm and a white insulating surface color (cream)
・ Printed wiring board (paper phenolic board) with 35μm thick copper wiring and a light brown color on the insulating layer surface
・ Printed wiring board (polyimide substrate) with copper wiring with a thickness of 35μm and an insulating layer surface of orange
・ Printed wiring board (blackened glass epoxy board) with 35μm thick copper wiring and black insulating layer surface

  In Comparative Example 5, a printed wiring board (glass epoxy board) having a copper wiring having a thickness of 35 μm and having a yellow insulating layer surface color is prepared, and a black negative type is provided on the printed wiring board. A photo solder resist ink (mixed with raw materials shown in Comparative Example 5U in Table 2) was applied and heated at 80 ° C. for 15 minutes. The thickness of the coating film of the photo solder resist ink on the copper wiring after heating was 15 μm. On the coating film of this photo solder resist ink, the obtained mixture (mixed raw materials shown in Comparative Example 5T in Table 2) was applied by a screen printing method to form a two-layer coating film.

  This coating film was preheated at 80 ° C. for 30 minutes.

Subsequently, the coating film is passed through a mask having a light-transmissive part, a low-light part having a light transmittance lower than that of the light-transmissive part, and a non-light-transmissive part having no light permeability. The coating film was exposed by irradiating with ultraviolet rays. The exposure amount in the portion irradiated with light that passes through the transmissive part in the coating film is 500 mJ / cm ² (first region), and the exposure amount in the part that is irradiated with light that passes through the low transmissive part is 80 mJ / cm ² (second region).

The exposed coating film was developed by spraying a 1% Na ₂ CO ₃ aqueous solution at a pressure of 0.2 MPa for 60 seconds.

  Subsequently, the coating film was heated at 160 ° C. for 1 hour. Thus, in Examples 1 to 12 and Comparative Examples 1 to 4, a film having a thickness of 25 μm was formed on the copper wiring. In Comparative Example 5, a film having a thickness of 40 μm was formed on the copper wiring.

  In addition, in the evaluation items of dam residue, adhesion, acid resistance, alkali resistance, plating resistance, solder heat resistance, pencil hardness and electric corrosion resistance, a printed wiring board (glass epoxy board) whose insulating layer surface color is yellow ) Evaluation was performed using the film formed above.

[Evaluation]
1. Appearance color The appearance of the film formed in each Example and Comparative Example was visually observed, and it was confirmed whether the first region and the second region could be clearly distinguished. As a result, it was evaluated that “A” was clearly distinguishable, “B” was distinguishable, and “C” was unclear.

2. Form a dam on an insulating layer using a mask that has a portion that is exposed at an irradiation dose of 500 mJ / cm ² and a portion that is not exposed and that forms solder dams with widths of 40 μm, 50 μm, 60 μm, and 70 μm. did. A cellophane adhesive tape was applied to the formed solder dam, and then a peeling test (tape test) was performed to peel it off. As a result of this peeling test, the remaining solder dam having the narrowest line width (dam remaining) was measured and determined as follows.
A: The line width of the thinnest solder dam is 40 μm B: The line width of the thinnest solder dam is 50 μm or 60 μm C: The line width of the thinnest solder dam is 70 μm or 70 μm

3. Adhesiveness According to the test method of JIS D0202, a cross cut of 100 squares was made in a grid pattern on the coating on the copper wiring of the test piece, and then the state of peeling after the peeling test with a cellophane adhesive tape was visually observed. The results were evaluated according to the following evaluation criteria.
A: Cross cut residual rate is 81 to 100%
B: Cross cut residual ratio is 71 to 80%
C: Cross-cut remaining rate is 70% or less

4). Acid resistance After immersing the test piece in 10% sulfuric acid for 30 minutes at room temperature, the appearance of the coating was visually observed. The results were evaluated according to the following evaluation criteria.
A: No abnormality is observed.
B: A little change is recognized.
C: A large change such as peeling of the film is observed.

5. Alkali resistance After immersing the test piece in 10% sodium hydroxide for 1 hour at room temperature, the appearance of the coating was visually observed. The results were evaluated according to the following evaluation criteria.
A: No abnormality is observed.
B: A little change is recognized.
C: A large change such as peeling of the film is observed.

6). Plating resistance The test piece was plated using a commercially available electroless nickel plating bath and electroless gold plating bath. The state of plating was observed. Furthermore, the cellophane adhesive tape peeling test was done with respect to the film after plating. The results were evaluated according to the following evaluation criteria.
A: Neither change in appearance due to plating, peeling due to tape peeling test, or penetration of plating is observed in the coating.
B: Appearance change due to plating is not recognized in the coating, but some peeling by the tape peeling test is recognized.
C: Lifting due to plating is recognized on the coating, and peeling by a tape peeling test is also recognized.

7). Solder heat resistance A water-soluble flux (product name: LONCO 3355-11, manufactured by London Chemical Co., Ltd.) was applied to the test piece, and the test piece was subsequently immersed in a molten solder bath at 260 ° C. for 10 seconds, followed by washing with water. The appearance of the coating on the test piece after repeating this series of operations three times was observed and evaluated according to the following evaluation criteria.
A: No abnormality is observed.
B: A little change is recognized.
C: A large change such as peeling of the film is observed.

8). Pencil Hardness The pencil hardness of the coating on the test piece was measured and evaluated in accordance with JIS K5400 using Mitsubishi High Uni (manufactured by Mitsubishi Pencil Co., Ltd.).

9. Electrolytic Corrosion Resistance A printed wiring board for evaluation was obtained by forming a film on the IPC B-25 comb-type electrode B coupon under the same conditions as in the test piece. While applying a DC 100V bias voltage to the comb-shaped electrode of this evaluation printed wiring board, the evaluation printed wiring board was placed at 40 ° C. and 90% R.D. H. For 500 hours. The presence or absence of migration in the printed wiring board for evaluation after this test was confirmed. The results were evaluated as follows.
A: Migration is not confirmed at all.
B: Some migration is confirmed.
C: Migration has occurred.

10. The difference between the L value (brightness) evaluation L value of the first region on the copper wiring by a color difference meter _{(L a)} and L value of the second region and _{(L b) (ΔL = L} a -L b ) Was measured and the results were evaluated as follows. The L value (brightness) refers to the lightness index “L ^* ” in the CIE 1976 L ^* a ^* b ^* color space defined in JIS 8781-4: 2013.
A: ΔL is +6 or more B: ΔL is +4 or more and less than +6 C: Less than ΔL + 4

11. The Y value evaluation colorimeter measures the difference (ΔY ₌ Y a -Y _b) the Y value of the first region on the copper wiring _{(Y a)} and Y value of the second region and _{(Y b)} The results were evaluated as follows. The Y value refers to the stimulus value “Y” in the XYZ color system.
A: ΔY is +3 or more B: ΔY is +1.5 or more and less than +3 C: ΔY is less than +1.5

  According to Table 1 and Table 2, in Examples 1-12 in which the crystalline epoxy resin (D) having a melting point of 130 ° C. or higher and the blue dispersant (E) are used, on the copper wiring, on the yellow insulating layer, The appearance color of the coating on the yellow-green insulating layer, the white insulating layer, the brown insulating layer, and the orange insulating layer is evaluated as “A” or “B”. On the other hand, in Comparative Examples 1 to 3 in which the blue dispersant (E) is not used and Comparative Example 4 in which the crystalline epoxy resin (D) having a melting point of 130 ° C. or higher is not used, on the yellow insulating layer, The appearance color of the coating on the yellow-green insulating layer, the white insulating layer, the brown insulating layer, and the orange insulating layer is evaluated as “C”. In Comparative Example 4, the appearance color on the black insulating layer is also evaluated as “C”.

  In Examples 1 to 12, the use of the blue dispersant (E) improves the dispersibility of the crystalline epoxy resin (D), which is more than the case where the blue dispersant (E) is not used. Because the air bubbles are generated more uniformly in the region, that is, the light transmittance of the first region is lower, the boundary between the first region and the second region regardless of the color of the insulating layer that is the background color. It is thought that became clear. In Comparative Example 4, since the crystalline epoxy resin (D) having a melting point of 130 ° C. or higher was not used, almost no bubbles were generated in the first region, and the first region and the first region were also formed on the black insulating layer. It seems that the boundary between the two areas was unclear.

  According to Table 1 and Table 2, in Examples 1-12 provided with the film obtained by hardening the coating film of one layer, the dam remainder and adhesiveness are evaluated as "A" or "B". On the other hand, in the comparative example 5 provided with the coating film obtained by curing the two-layer coating film, both the dam residue and the adhesiveness are evaluated as “C”.

  This is because the film of Comparative Example 5 is a film obtained by curing a two-layer coating film, so the film thickness is thicker than the coating films of Examples 1 to 12, and the coating film is deeper than the surface layer during exposure. It is thought that this is because the resin is not sufficiently cured over the entire area.

  According to Table 1 and Table 2, in Examples 1-12 in which the crystalline epoxy resin (D) having a melting point of 130 ° C. or higher is used, the L value evaluation and the Y value evaluation are evaluated as “A” or “B”. ing. On the other hand, in Comparative Example 4 in which the crystalline epoxy resin (D) having a melting point of 130 ° C. or higher is not used, both the L value evaluation and the Y value evaluation are evaluated as “C”.

  In Examples 1 to 12, bubbles were formed in the first region by using a crystalline epoxy resin (D) having a melting point of 130 ° C. or higher than when not using a crystalline epoxy resin (D) having a melting point of 130 ° C. or higher. It is considered that the L value evaluation and the Y value evaluation were highly evaluated because many bubbles were generated and the bubbles reflected light.

  According to Table 1 and Table 2, in Example 2 where the content ratio of the blue dispersant with respect to the carboxyl group-containing resin is 1.9% by mass, and in Example 8 where the content is 3% by mass, yellow wiring is formed on the copper wiring. The appearance color of the coating on the insulating layer, the yellow-green insulating layer, the white insulating layer, the brown insulating layer, the orange insulating layer and the black insulating layer, as well as the dam residue and adhesion are A ”. In Example 9 in which the content of the blue dispersant with respect to the carboxyl group-containing resin is 5% by mass, the yellow insulating layer, the yellow-green insulating layer, the white insulating layer, the brown insulating layer, and orange The appearance color on the insulating layer on the color insulating layer is evaluated as “B”, and the remaining dam and adhesion are evaluated as “A”. In Example 10 in which the content of the blue dispersant with respect to the carboxyl group-containing resin is 9.6% by mass, and in Example 11 which is 11.5% by mass, the copper wiring, the yellow insulating layer, the yellow green The appearance color on the insulating layer, on the white insulating layer, on the brown insulating layer, and on the orange insulating layer is evaluated as “B”, and the rest of the dam is evaluated as “B”.

  From these results, the adhesiveness between the printed wiring board and the coating is particularly high if the content of the blue dispersant with respect to the carboxyl group-containing resin is 5% by mass or less, and the first region and the second region are 3% by mass or less. It can be seen that the boundary with the second region is particularly clear.

  The blue dispersant (E) is preferably 0.1 to 10% by mass and more preferably 0.5 to 5% by mass with respect to the carboxyl group-containing resin (A) contained in the solder resist composition. Preferably, it is 1 to 3 mass%.

Claims (11)

Carboxyl group-containing resin (A),
One or more photopolymerizable compounds (B) selected from the group consisting of photopolymerizable monomers and photopolymerizable prepolymers,
Photopolymerization initiator (C),
Crystalline epoxy resin (D) having a melting point of 130 ° C. or higher and blue dispersant (E)
A solder resist composition comprising:   The solder resist composition according to claim 1, wherein the blue dispersant (E) contains a copper phthalocyanine sulfonate derivative.   The soldering resist composition of Claim 1 or 2 containing the coloring agent (F) containing at least one among a black coloring agent and a red coloring agent.   The solder resist composition according to any one of claims 1 to 3, wherein the carboxyl group-containing resin (A) includes a carboxyl group-containing resin (A1) having a photopolymerizable functional group. It consists of a cured product of the solder resist composition according to any one of claims 1 to 4.
A film comprising a first region and a second region having a light transmittance higher than that of the first region. The first region contains air bubbles;
The coating according to claim 5, wherein the second region does not contain bubbles or a ratio of bubbles is lower than that of the first region. Comprising a printed wiring board and the coating according to claim 5 or 6,
The printed wiring board includes an insulating layer and a copper wiring on the insulating layer,
The coated film is a coated printed wiring board covering the insulating layer and the wiring.   The coated printed wiring board according to claim 7, wherein the color of the insulating layer is yellow, yellow-green, white, cream, brown, orange, green, or black.   The coated printed wiring board according to claim 7 or 8, wherein the printed wiring board includes at least one of a rigid material and a flexible material. <a> a step of forming a coating film comprising the solder resist composition according to any one of claims 1 to 4,
<B> including the step of exposing the coating film, and <c> forming the coating film by heating the coating film after exposure,
In the step <b>, the first portion of the coating film is irradiated with light, and the second portion of the coating film different from the first portion is not irradiated with light, or the first portion Irradiate light so that the exposure amount is lower than the part of
In the step <c>, by generating bubbles in the first portion by heating, the first region containing bubbles in the coating and the ratio of bubbles not containing bubbles or the first ratio A method for producing a film, wherein a second region lower than the region is formed. <D> The solder resist composition according to any one of claims 1 to 4, wherein the insulating layer and the wiring are disposed on a printed wiring board including an insulating layer and a copper wiring on the insulating layer. The process of forming a coating film by arranging to cover,
<E> a step of exposing the coating film;
<F> a step of developing the coating film after exposure with an alkaline developer, and <g> a step of forming the coating film by heating the coating film after development,
In the step <e>, the first part of the coating film is irradiated with light, and the second part different from the first part of the coating film has an exposure amount that is higher than that of the first part. Irradiate with light to lower it,
In the step <g>, by generating bubbles in the first portion by heating, the first region containing bubbles in the coating and the ratio of bubbles not containing bubbles or the first ratio A method for producing a coated printed wiring board, wherein a second region lower than the region is formed.

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