Resin composition, dry film, cured product, and light-emitting element mounting substrate

Abstract

The invention provides a resin composition. The resin composition can be used for manufacturing a white solder resist which has high reflectivity and is not easy to generate defective products. One embodiment of the present invention is a resin composition. The resin composition contains: an alkali-soluble polymer (A) containing a cyclohexyl group and a carboxyl group; a urethane polymer (B); a thiol group-containing compound (C); and a white pigment (D).

Description

Technical Field

[0001] This invention relates to resin compositions, dry films, cured products, and light-emitting element mounting substrates. Background Technology

[0002] In the display industry, white solder resist is sometimes used. By using white solder resist, not only can it fulfill the function of a permanent protective film for circuits as required by ordinary solder resists, but it can also improve reflectivity and brightness when mounting LEDs, etc.

[0003] For example, Patent Document 1 discloses a technique for manufacturing a white solder resist using a resin composition containing cyclohexyl methacrylate as a copolymer raw material and also using titanium dioxide, etc.

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 11-087927 Summary of the Invention

[0005] The problem to be solved by the present invention However, it is known that the white solder resist involved in the existing technology is prone to producing defective products when trying to achieve high reflectivity.

[0006] Therefore, the objective of this invention is to provide a resin composition capable of producing a white solder resist with high reflectivity and low susceptibility to defects.

[0007] Methods for solving problems The inventors of this invention have discovered that by combining specific components, the above-mentioned problems can be solved, thereby completing this invention. That is, this invention is as follows.

[0008] One aspect of the present invention is a resin composition.

[0009] The resin composition comprises: an alkali-soluble polymer (A) containing cyclohexyl and carboxyl groups; a urethane polymer (B); a compound containing thiol groups (C); and a white pigment (D).

[0010] Preferably, the white pigment (D) contains titanium dioxide.

[0011] Preferably, the urethane polymer (B) contains a carboxyl group.

[0012] Preferably, when the total mass of the alkali-soluble polymer (A), the urethane polymer (B), and the compound (C) is 100 parts by mass, the content of the white pigment (D) is 200-500 parts by mass in terms of solid components.

[0013] Preferably, the resin composition contains a polymerization initiator.

[0014] Another aspect of the invention is to coat the resin composition onto a first film to obtain a dry film.

[0015] Another aspect of the invention is a cured product obtained using the resin composition or the dry film.

[0016] Another aspect of the present invention is a light-emitting element mounting substrate having the cured material.

[0017] The effects of the invention According to the present invention, a resin composition can be provided that can produce a white solder resist with high reflectivity and low susceptibility to defects. Attached Figure Description

[0018] Figure 1 A top-view concept diagram showing a portion of the substrate on which the light-emitting element is mounted. Detailed Implementation

[0019] In this specification, where isomers of the described compounds exist, all possible isomers may be used in this invention unless otherwise stated.

[0020] In this specification, where the upper and lower limits of the numerical range are recorded separately, it is considered, to the extent that no contradiction exists, that all combinations of the lower and upper limits are actually recorded.

[0021] Unless otherwise stated, all measurements in this specification are performed at room temperature (25°C).

[0022] In this specification, the number-average molecular weight and weight-average molecular weight are determined by gel permeation chromatography (GPC) and converted according to the calibration curves made using standard polystyrene.

[0023] In this specification, the components contained in the resin composition and the components contained in the resin layer, which is a dried coating film of the resin composition, are sometimes not described separately.

[0024] In this specification, "(meth)acrylic acid" means that it includes both "acrylic acid" and "methacrylic acid". Additionally, "(meth)acrylate" means that it includes both "acrylate" and "methacrylate".

[0025] In this specification, acid value refers to the value calculated by dissolving the sample in a titration solvent in a 1:1 mass ratio of xylene and dimethylformamide, titrating it using a 0.1 mol / L potassium hydroxide-ethanol solution via potentiometric titration, with the inflection point on the titration curve as the endpoint, based on the titration volume of potassium hydroxide solution up to the endpoint.

[0026] The composition and usage / application of the resin composition disclosed herein are described below.

[0027] <<<Composition of the Resin Composition>>> The resin composition disclosed herein preferably comprises: an alkali-soluble polymer (A) containing cyclohexyl and carboxyl groups; a urethane polymer (B); a compound (C) containing thiol groups (hereinafter also referred to as thiol-containing compound (C)); and a white pigment (D).

[0028] The resin compositions disclosed herein preferably comprise a thermosetting resin (E).

[0029] The resin compositions disclosed herein preferably contain a polymerization initiator (F).

[0030] The resin compositions disclosed herein may also contain other components (G).

[0031] The following is a description of each component.

[0032] <<Alkali-soluble polymer (A)>> Examples of alkali-soluble polymers (A) include: copolymers of monomers containing cyclohexyl groups and monomers containing carboxyl groups; modified products in which the terminal portions of a polymer containing cyclohexyl groups are replaced with functional groups containing carboxyl groups; and modified products in which the terminal portions of a polymer containing carboxyl groups are replaced with functional groups containing cyclohexyl groups. Preferably, the alkali-soluble polymer (A) is a copolymer of monomers having cyclohexyl groups and monomers containing carboxyl groups.

[0033] As monomers containing cyclohexyl groups, without particular limitation, examples include: cyclohexyl (meth)acrylate, 1,4-cyclohexanediethanol mono(meth)acrylate, 3,4-epoxycyclohexyl (meth)acrylate, and other compounds containing cyclohexyl and (meth)acryloyl groups.

[0034] As monomers containing carboxyl groups, without particular limitation, examples include: (meth)acrylic acid, carboxyethyl (meth)acrylate, mono(2-(meth)acryloyloxyethyl) succinate, monohydroxyethyl (meth)acrylate of phthalate, and other compounds containing carboxyl and (meth)acryloyl groups.

[0035] An alkali-soluble polymer (A) can be produced by copolymerizing these monomers under known conditions. The ratio of the cyclohexyl monomer to the carboxyl monomer can be arbitrary, but from the perspective of resolution and reflectivity, a ratio of 30:70 to 70:30 by mass is preferred.

[0036] In addition, in this case, the monomers used to copolymerize the alkali-soluble polymer (A) may also include monomers other than monomers with cyclohexyl groups and monomers containing carboxyl groups.

[0037] Other monomers are not specifically limited. Examples of other monomers include: methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-methylbutyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and other methacrylates that do not contain a cyclohexyl group.

[0038] The proportion of other monomers relative to all monomers constituting the alkali-soluble polymer (A) is, for example, 50 mol% or less, 30 mol% or less, 25 mol% or less, or 20 mol% or less. The lower limit of the proportion of other monomers is, for example, 1 mol%, 2 mol%, 5 mol%, or 10 mol%.

[0039] The alkali-soluble polymer (A) is preferably a vinyl unsaturated group (a hydrocarbon group having an unsaturated double bond). As a vinyl unsaturated group, (meth)acryloyl group is preferred.

[0040] Alkali-soluble polymers (A) having vinyl unsaturated groups can be manufactured, for example, by further adding glycidyl (meth)acrylate, α-methylglycidyl (meth)acrylate, or other compounds having an epoxy group and one or more vinyl unsaturated groups (preferably (meth)acryloyl) in the molecule to the copolymer of the aforementioned cyclohexyl monomer and a carboxyl monomer.

[0041] Alkali-soluble polymer (A) can be used alone or in combination.

[0042] The acid value of the alkali-soluble polymer (A) is preferably 20-300 (mgKOH / g), more preferably 40-250 (mgKOH / g), and particularly preferably 50-200 (mgKOH / g). By setting the acid value of the alkali-soluble polymer (A) to this range, it is easier to obtain cured products with excellent developability, resolution, and reflectivity.

[0043] The carboxylic acid equivalent of the alkali-soluble polymer (A) is preferably 100-1000 (g / eq), more preferably 200-800 (g / eq), and particularly preferably 300-500 (g / eq). By making the carboxylic acid equivalent of the alkali-soluble polymer (A) within this range, it is easier to obtain cured products with excellent developability, resolution, and reflectivity.

[0044] The cyclohexyl equivalent of the alkali-soluble polymer (A) is preferably 100-1000 (g / eq), more preferably 200-800 (g / eq), and particularly preferably 300-600 (g / eq). By making the cyclohexyl equivalent of the alkali-soluble polymer (A) within this range, it is easier to obtain cured products with excellent properties.

[0045] When the alkali-soluble polymer (A) contains (meth)acryloyl groups, the (meth)acrylic acid equivalent of the alkali-soluble polymer (A) is preferably 100-2000 (g / eq), more preferably 200-1800 (g / eq), and particularly preferably 300-1500 (g / eq). By making the carboxylic acid equivalent of the alkali-soluble polymer (A) within this range, it is easier to obtain cured products with excellent properties.

[0046] The weight-average molecular weight of the alkali-soluble polymer (A) can be 1,500-150,000, preferably 1,500-100,000, more preferably 1,500-50,000, and particularly preferably 1,500-40,000. By making the weight-average molecular weight of the alkali-soluble polymer (A) fall within this range, it is easier to obtain cured products with excellent properties.

[0047] The content of alkali-soluble polymer (A) in the resin composition is based on the total mass of the solid components of the resin composition after removing the white pigment, and is preferably 5% or more by mass, 8% or more by mass, or 10% or more by mass, and is also preferably 50% or less by mass, 45% or less by mass, or 40% or less by mass.

[0048] <<Carbamate Polymer (B)>> The urethane polymer (B) is a reaction product of a polyol having two or more hydroxyl groups in one molecule and a polyisocyanate having two or more isocyanate groups in one molecule.

[0049] The urethane polymer (B) can be any known material and is not particularly limited thereto. The urethane polymer (B) is preferably a carboxyl-containing urethane polymer (hereinafter referred to as a carboxyl-containing urethane resin). The following provides a detailed description of the carboxyl-containing urethane resin preferred as the urethane polymer (B).

[0050] The carboxyl-containing urethane resin is preferably obtained using a compound having an isocyanate group not directly linked to an aromatic ring. The resin composition, by including a carboxyl-containing urethane resin, improves adhesion to the substrate and developability. The carboxyl-containing urethane resin can be either a carboxyl-containing urethane resin with vinyl unsaturated groups or a carboxyl-containing urethane resin without vinyl unsaturated groups. Among these, a carboxyl-containing urethane resin with vinyl unsaturated groups is preferred due to its excellent photocurability and developability.

[0051] Specifically, the carboxyl-containing urethane resin is preferably a urethane resin having a terminal phenolic hydroxyl group introduced by reacting a compound (a) having an isocyanate group not directly connected to an aromatic ring with a compound (b) having two or more alcoholic hydroxyl groups in one molecule and a compound (c) having one alcoholic hydroxyl group and one or more phenolic hydroxyl groups in one molecule, which acts as a reaction terminator. However, it can also be obtained by reacting a compound (a) having an isocyanate group not directly connected to an aromatic ring with a compound (b) having two or more alcoholic hydroxyl groups in one molecule. The compound (b) includes: a urethane resin in which phenolic hydroxyl groups are introduced on the molecular side chain using a compound having phenolic hydroxyl groups and two or more alcoholic hydroxyl groups, or a urethane resin in which carboxyl groups are introduced on the molecular side chain using a compound having a carboxyl group and two or more alcoholic hydroxyl groups in one molecule, etc. In the latter urethane resin, as a capping agent (reaction terminator), a compound (c) having one or more alcoholic hydroxyl groups and one or more phenolic hydroxyl groups in one molecule can be used. In addition, various known reaction terminators such as aliphatic alcohols, monohydroxyl mono(meth)acrylate compounds, and monocarboxylic acids having functional groups such as alcoholic hydroxyl groups, amino groups, and mercapto groups that can undergo addition or condensation reactions with isocyanate groups can also be used.

[0052] When the carboxyl-containing urethane resin is, for example, the suitable urethane resin, the compound (a) having an isocyanate group not directly attached to the aromatic ring, the compound (b) having two or more alcoholic hydroxyl groups in one molecule, and the compound (c) having one alcoholic hydroxyl group in one molecule, which acts as a reaction terminator, can be reacted together. Alternatively, the compound (a) having an isocyanate group not directly attached to the aromatic ring and the compound (b) having two or more alcoholic hydroxyl groups in one molecule can be reacted together, and then reacted with the compound (c) having one alcoholic hydroxyl group in one molecule, which acts as a reaction terminator. In the case of other urethane resins, a compound (a) having an isocyanate group not directly attached to an aromatic ring and a compound (b) having a phenolic hydroxyl group and / or a carboxyl group and two or more alcoholic hydroxyl groups in one molecule can be reacted together with a reaction terminator. However, from the viewpoint of molecular weight adjustment, the above-mentioned compound (a) having an isocyanate group not directly attached to an aromatic ring can be reacted with the above-mentioned compound (b), and then reacted with a reaction terminator.

[0053] The reaction is carried out under catalyst-free conditions by stirring and mixing at room temperature to 100°C, but heating to 70-100°C is preferred to increase the reaction rate. The reaction ratio (molar ratio) of the above components (a)-(c) is appropriately set as (a):(b) = 1:1-2:1, preferably 1:1-1.5:1, and (a+b):(c) = 1:0.01-0.5, preferably 1:0.02-0.3.

[0054] As the compound (a) having an isocyanate group not directly linked to the aromatic ring, various known compounds having an isocyanate group not directly linked to the aromatic ring can be used, and the compound is not limited to a specific compound. Specific examples of the compound (a) having an isocyanate group not directly linked to the aromatic ring include, for example, aliphatic diisocyanates such as hexamethylene diisocyanate, branched aliphatic diisocyanates such as trimethylhexamethylene diisocyanate, isophorone diisocyanate, (ortho, meta, or para)-(hydrogenated)xylene diisocyanate, methylene bis(cyclohexyl isocyanate), cyclohexane-1,3-dimethylene diisocyanate, and cyclohexane-1,4-dimethylene diisocyanate. Among these, hexamethylene diisocyanate as an aliphatic diisocyanate and trimethylhexamethylene diisocyanate as a branched aliphatic diisocyanate are preferred. These compounds having an isocyanate group not directly linked to the aromatic ring can be used alone or in mixtures of two or more. When using this diisocyanate compound, a cured product with excellent environmental resistance and low warpage can be obtained. Furthermore, aromatic diisocyanates can also be used without compromising the effects of the present invention.

[0055] Next, as a compound (b) having two or more alcoholic hydroxyl groups, various known polyols can be used, without limitation to specific compounds, but the following can be appropriately used: polycarbonate-based polyols such as polycarbonate diols, polyether-based polyols, polyester-based polyols, polyolefin-based polyols, acrylic-based polyols, polybutadiene-based polyols, polyisoprene-based polyols, hydrogenated polybutadiene-based polyols, hydrogenated isoprene-based polyols, phosphorus-containing diols, bisphenol A-based alkylene oxide adduct diols, compounds containing carboxyl and alcoholic hydroxyl groups, compounds containing phenolic and alcoholic hydroxyl groups, phosphorus-containing polyols, etc. Among these, polycarbonate-based polyols are preferred because they can produce cured products with excellent weather resistance and flexibility. Examples of polycarbonate diols include: polycarbonate diols containing one or more repeating units derived from linear aliphatic diols as constituent units (b-1); polycarbonate diols containing one or more repeating units derived from alicyclic diols as constituent units (b-2); and polycarbonate diols containing repeating units derived from both linear aliphatic diols and alicyclic diols as constituent units (b-3). Furthermore, when using compounds having a carboxyl group and two or more alcoholic hydroxyl groups (b-4), or further using compounds having phenolic hydroxyl groups and two or more alcoholic hydroxyl groups (b-5), the molecular side chains can be endowed with functional groups (phenolic hydroxyl groups, carboxyl groups). When using phosphorus-containing polyols (b-6), flame retardancy can be imparted to urethane resins. These compounds (b-1)-(b-6) can be used alone or in mixtures of two or more.

[0056] Specific examples of polycarbonate diols (b-1) that contain one or more repeating units derived from linear aliphatic diols as constituent units include: polycarbonate diols derived from 1,6-hexanediol, polycarbonate diols derived from 1,5-pentanediol and 1,6-hexanediol, polycarbonate diols derived from 1,4-butanediol and 1,6-hexanediol, polycarbonate diols derived from 3-methyl-1,5-pentanediol and 1,6-hexanediol, and polycarbonate diols derived from 1,9-nonanediol and 2-methyl-1,8-octanediol.

[0057] As a specific example of the polycarbonate diol (b-2) that contains one or more repeating units derived from alicyclic diols as constituent units, examples include polycarbonate diols derived from 1,4-cyclohexanediethanol.

[0058] As a specific example of the polycarbonate diol (b-3) that comprises repeating units derived from both linear aliphatic diols and alicyclic diols, examples include polycarbonate diols derived from 1,6-hexanediol and 1,4-cyclohexanediol.

[0059] Specific examples of the compounds (b-4) having a carboxyl group and two or more alcoholic hydroxyl groups include dimethylolpropionic acid and dimethylolbutyric acid. By using such compounds having a carboxyl group and two or more alcoholic hydroxyl groups, carboxyl groups can be readily introduced into urethane resins.

[0060] Specific examples of compounds (b-5) having phenolic hydroxyl groups and two or more alcoholic hydroxyl groups include: 6-hydroxy-5-methyl-1,3-benzyl alcohol, 2,4-di(hydroxymethyl)-6-cyclohexylphenol, 3,3'-methylenebis(2-hydroxy-5-methylbenzyl alcohol), 4,4'-(1-methylethylidene)bis[2-methyl-6-hydroxymethylphenol], 4,4'-[1,4-phenylenebis(1-methylethylidene)bis[2-methyl-6-hydroxymethylphenol], 2-hydroxy-5-fluoro- 1,3-Benzenediethanol, 4,4'-Methyl-2-methyl-6-hydroxymethylphenol, 4,4'-Methylenebis(2,5-dimethyl-3-hydroxymethylphenol), 4,4'-Cyclohexylmethylenebis(2-methyl-6-hydroxymethylphenol), 4,4'-Cyclohexylmethylenebis(2-cyclohexyl-6-hydroxymethylphenol), 2,6-bis[(2-hydroxy-3-hydroxymethyl-5-methylphenyl)methyl]-4-methylphenol, 2-hydroxy-5-ethyl-1,3-benzenedimethanol, 2-H-dihydroxy-4,5- Dimethyl-1,3-benzyl alcohol, 2-hydroxy-5-(1-methylpropyl)-1,3-benzyl alcohol, 4-(1,1-dimethylethyl)-2-hydroxy-1,3-benzyl alcohol, 2-hydroxy-5-cyclohexyl-1,3-benzyl alcohol, 2-hydroxy-5-(1,1,3,3-tetramethylbutyl)-1,3-benzyl alcohol, 2,6-bis[(4-hydroxy-3-hydroxymethyl-2,5-dimethylphenyl)methyl]-3,4-dimethylphenylcresol, 2,6-bis[(4-hydroxy-3-hydroxymethyl-2,5-dimethylphenyl)methyl]-3,4-dimethylphenylcresol, Compounds containing phenolic and alcoholic hydroxyl groups, such as methyl-2,5-dimethylphenyl[methyl]-4-cyclohexylphenol, 2-hydroxy-1,3,5-benzenetriethanol, 3,5-dimethyl-2,4,6-tris(hydroxymethyl)phenol, 4,4',4"-ethidintris(2-methyl-6-hydroxymethyl)phenol, 2,3,5,6-tetra(hydroxymethyl)-1,4-benzenediol, and 4,4'-methylenebis[2,6-bis(hydroxymethyl)phenol], can be readily introduced into urethane resins through the use of these compounds.

[0061] The polycarbonate diol is preferably of number average molecular weight of 200-5000. When the polycarbonate diol contains repeating units derived from linear aliphatic diols and alicyclic diols as constituent units, and the copolymerization ratio of linear aliphatic diols to alicyclic diols is 3:7-7:3 by mass, it is preferably of number average molecular weight of 400-2000.

[0062] Examples of bisphenol A-based alkylene oxide adduct diols include: ethylene oxide adducts, propylene oxide adducts, and butane oxide adducts of bisphenol A.

[0063] Specific examples of the aforementioned phosphorus-containing polyols include: FC-450 (manufactured by Asahi Denka Kogyo Co., Ltd.), M-Ester (manufactured by Sanko Co., Ltd.), and M-Ester-HP (manufactured by Sanko Co., Ltd.). By using these phosphorus-containing polyols, phosphorus compounds can be introduced into urethane resins, thereby imparting flame retardancy.

[0064] Next, as a compound (c) having an alcoholic hydroxyl group, various known monohydroxy compounds can be used, without limitation to specific compounds, including: methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, pentanol, hexanol, octanol, 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, cyclohexanediethanol mono (meth)acrylate, caprolactone or alkylene oxide adducts of the above (meth)acrylates, glycerol di (meth)acrylate, trimethylolpropane di (meth)acrylate, pentaerythritol tri (meth)acrylate, dipentaerythritol penta (meth)acrylate, ditrimethylolpropane tri (meth)acrylate, allyl alcohol, aryloxyethanol, glycolic acid, hydroxypentanoic acid, etc., but not limited to these compounds.

[0065] Compound (c), which has a phenolic hydroxyl group and an alcoholic hydroxyl group in one molecule, is used for the purpose of introducing phenolic hydroxyl groups into polyurethane and also acts as a capping agent for polyurethane. In particular, compounds having both an alcoholic hydroxyl group and a phenolic hydroxyl group in the molecule that can react with isocyanates also act as reaction terminators. Specific examples of such compounds (c) include: hydroxymethylphenol, hydroxymethylcresol, hydroxymethyl di-tert-butylphenol, p-hydroxyphenyl-2-methanol, p-hydroxyphenyl-3-propanol, p-hydroxyphenyl-4-butanol, hydroxyethylcresol, 2,6-dimethyl-4-hydroxymethylphenol, 2,4-dimethyl-6-hydroxymethylphenol, 2,3,6-trimethyl-4-hydroxymethylphenol, 2-cyclohexyl-4-hydroxymethyl-5-methylphenol, and 4-methyl-6-hydroxymethylphenol. Hydroxyalkylphenols or hydroxyalkylcresols such as 1,2-diol and 4-(1,1-dimethyl(ethyl))-6-hydroxymethylbenzene-1,2-diol; esters of phenols with carboxyl substituents such as hydroxybenzoic acid, hydroxyphenylbenzoic acid, or hydroxyphenoxybenzoic acid with ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, etc.; monoethylene oxide adducts of bisphenols, monopropylene oxide adducts of bisphenols, p-hydroxyphenylethanol, etc., but not limited to these compounds. These compounds (c) can be used alone or in mixtures of two or more.

[0066] The weight-average molecular weight of the carboxyl-containing urethane resin is preferably 500-100,000, more preferably 8,000-50,000. Here, the weight-average molecular weight is the polystyrene equivalent value determined by gel permeation chromatography. By setting the weight-average molecular weight of the carboxyl-containing urethane resin to 500 or higher, the elongation, flexibility, and strength of the cured film are all improved. By setting it to below 100,000, development is possible, and the solubility is improved without the viscosity after dissolution being too high.

[0067] The acid value of the carboxyl-containing urethane resin is preferably in the range of 10-120 mg KOH / g, more preferably in the range of 20-80 mg KOH / g. With an acid value of 10 mg KOH / g or higher, the reactivity with thermosetting components is further enhanced, and the heat resistance is further improved. On the other hand, with an acid value of 120 mg KOH / g or lower, the properties of the cured film as a corrosion resist, such as alkali resistance and electrical properties, are further improved. Furthermore, the acid value of the resin is a value determined according to JIS K5601-1-2-1:1999 standard.

[0068] These carboxyl-containing urethane resins can be used alone or in combination.

[0069] The urethane polymer (B) can also be a carboxyl-free urethane resin obtained by means of synthesizing urethane resins without using a compound (b-4) having a carboxyl group and two or more alcoholic hydroxyl groups. The urethane polymer (B) can also be a substance obtained using a compound having an isocyanate group directly attached to an aromatic ring (e.g., toluene diisocyanate, diphenylmethane diisocyanate, etc.).

[0070] In the synthesis of urethane polymer (B), when a compound having a reactive group such as (meth)acryloyl group is used as the aforementioned compound (c) having an alcoholic hydroxyl group, a urethane polymer (B) with a reactive group introduced at the end can be easily obtained.

[0071] The urethane polymer (B) can be used alone or in combination.

[0072] When the urethane polymer (B) contains a carboxyl group, the acid value of the urethane polymer (B) is preferably 10-300 (mgKOH / g), more preferably 20-200 (mgKOH / g), and particularly preferably 30-100 (mgKOH / g). By making the acid value of the urethane polymer (B) within this range, it is easier to obtain cured products with excellent properties.

[0073] When the urethane polymer (B) contains a carboxyl group, the carboxylic acid equivalent of the urethane polymer (B) is preferably 100-2500 (g / eq), more preferably 200-2000 (g / eq), and particularly preferably 500-1500 (g / eq). By making the carboxylic acid equivalent of the urethane polymer (B) fall within this range, it is easier to obtain cured products with excellent properties.

[0074] The weight-average molecular weight of the urethane polymer (B) is preferably 2,000-150,000, more preferably 3,000-100,000, and particularly preferably 4,000-50,000. By making the weight-average molecular weight of the urethane polymer (B) fall within this range, it is easier to obtain cured products with excellent properties.

[0075] The content of urethane polymer (B) in the resin composition is based on the total mass of the solid components of the resin composition after removing the white pigment, and is preferably 5% or more by mass, 8% or more by mass, or 10% or more by mass, and is also preferably 50% or less by mass, 45% or less by mass, or 40% or less by mass.

[0076] Here, the ratio (B / A) of the content of alkali-soluble polymer (A) to the content of urethane polymer (B) in the resin composition is preferably 0.1 or more, 0.2 or more, or 0.5 or more, and more preferably 10.0 or less, 5.0 or less, or 4.0 or less.

[0077] The ratio (C / A) of the content of alkali-soluble polymer (A) to the content of thiol-containing compound (C) is preferably 0.10 or more, or 0.20 or more, and even more preferably 2.00 or less, 1.50 or less, 1.00 or less, or 0.60 or less.

[0078] The ratio (C / B) of the content of urethane polymer (B) to the content of thiol-containing compound (C) is preferably 0.10 or more, or 0.20 or more, and more preferably 2.00 or less, 1.50 or less, 1.00 or less, or 0.60 or less.

[0079] <<Thiol-containing compounds (C)>> The thiol-containing compound (C) is a compound having at least one (preferably two or more) thiol group in one molecule.

[0080] Examples of thiol-containing compounds (C) include: alkyl thiols; polyethers having terminal thiol groups (thiol groups); polysulfides having terminal thiol groups (thiol groups); thiol compounds obtained by reacting an epoxy compound with hydrogen sulfide; thiol compounds having terminal thiol groups obtained by reacting a polythiol compound with an epoxy compound; esters of polyols and thiol organic acids; thiol-modified (meth)acrylates, etc.

[0081] Specific examples of monofunctional thiol-containing compounds (C) include: β-mercaptopropionic acid, methyl 3-mercaptopropionic acid, 2-ethylhexyl 3-mercaptopropionic acid, octyl 3-mercaptopropionic acid, 3-mercaptomethoxybutylpropionic acid, octadecyl 3-mercaptopropionic acid, etc.

[0082] Specific examples of multifunctional thiol-containing compounds (C) include: 1,4-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetra(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]isocyanate, tetraethylene glycol bis(3-mercaptopropionate), bispentaerythritol hexa(3-mercaptopropionate), pentaerythritol tetra(3-mercaptobutyrate), 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,4-bis(3-mercaptobutyryloxy)butane, etc.

[0083] The thiol-containing compound (C) preferably includes a mercapto-modified (meth)acrylate. The mercapto-modified (meth)acrylate is a compound obtained by reacting a polythiol compound with a multifunctional (meth)acrylate. Examples of mercapto-modified (meth)acrylates include, for instance, the compound disclosed in Japanese Patent Application Publication No. 2023-097118.

[0084] Thiol-containing compounds (C) can be used alone or in combination.

[0085] The content of thiol-containing compounds (C) in the resin composition is based on the total mass of the solid components of the resin composition after removing the white pigment, and is preferably 2% or more by mass, 5% or more by mass, 10% or more by mass, or 15% or more by mass, and is also preferably 40% or less by mass, 30% or less by mass, or 20% or less by mass.

[0086] <<White Pigment (D)>> White pigment (D) can be any existing, known white pigment.

[0087] Examples of white pigments (D) include oxides such as titanium dioxide, zinc oxide, aluminum oxide, silicon dioxide, and magnesium oxide; sulfides such as zinc sulfide; hydroxides such as lead hydroxide and aluminum hydroxide; sulfates such as barium sulfate; and carbonates such as calcium carbonate. Additionally, white pigments can also be coated particles whose surfaces are coated with a white material. Surface treatments can also be applied to white pigments to improve reflectivity, etc.

[0088] White pigment (D) can be used alone or in combination.

[0089] The white pigment (D) is preferably composed of titanium dioxide.

[0090] The crystal form of titanium dioxide is not particularly limited. For example, titanium dioxide can be rutile titanium dioxide or anatase titanium dioxide.

[0091] The average particle size of titanium dioxide is not particularly limited. The volume average particle size (D50) of titanium dioxide can be, for example, 100–1000 nm, 120–500 nm, or 150–400 nm.

[0092] When the total mass of the alkali-soluble polymer (A), the urethane polymer (B), and the thiol-containing compound (C) is 100 parts by mass, the content of white pigment (D) (or titanium dioxide content), converted to solid components, is preferably 100 parts by mass or more, 150 parts by mass or more, 200 parts by mass or more, or 250 parts by mass or more; more preferably 600 parts by mass or less, 550 parts by mass or less, 500 parts by mass or less, 450 parts by mass or less, or 400 parts by mass or less. More specifically, the content of white pigment (D) (or titanium dioxide content) is preferably 200-500 parts by mass, or 250-400 parts by mass.

[0093] <<Thermosetting Resins (E)>> Examples of thermosetting resins (E) include: epoxy resins, polyfunctional oxobutane compounds, cyclic sulfide resins having two or more cyclic ether groups and / or cyclic thioether groups in the molecule, polyisocyanate compounds (or blocked isocyanate compounds) having two or more isocyanate groups (or blocked isocyanate groups) in one molecule, amine resins (or their derivatives) such as melamine resins and benzoguanamine resins, bismaleimide, oxazine, cyclic carbonate compounds, carbodiimide resins, and other known thermosetting resins.

[0094] The thermosetting resin (E) is preferably an epoxy resin.

[0095] Examples of epoxy resins include: bisphenol type epoxy resins (such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, bisphenol M type epoxy resin, bisphenol P type epoxy resin, bisphenol Z type epoxy resin, etc.), phenolic type epoxy resins (bisphenol A phenolic type epoxy resin, phenolic type epoxy resin, cresol phenolic type epoxy resin, etc.), biphenyl type epoxy resin, biphenyl phenolic type epoxy resin, biphenyl aralkyl type epoxy resin, arylalkylene type epoxy resin, tetraphenylethane type epoxy resin, naphthalene type epoxy resin, and anthracene type epoxy resin. Epoxy-based epoxy resins, dicyclopentadiene-based epoxy resins, norbornene-based epoxy resins, trihydroxyphenylmethane-based epoxy resins, hydantoin-based epoxy resins, tetraphenylethane-based epoxy resins, brominated epoxy resins, glycidylamine-based epoxy resins, alicyclic epoxy resins, diglycidyl phthalate resins, tetraglycidyl dimethyl ethane resins, glycidyl methacrylate copolymer epoxy resins, cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resins, epoxy-modified polybutadiene rubber derivatives, CTBN-modified epoxy resins, etc.

[0096] Thermosetting resins (E) can be used alone or in combination.

[0097] The content of thermosetting resin (E) (or epoxy resin content) in the resin composition is based on the total mass of the solid components of the resin composition after removing the white pigment, and is preferably 5% or more by mass, 10% or more by mass, or 15% or more by mass, and preferably 40% or less by mass, 30% or less by mass, or 25% or less by mass.

[0098] <<Polymerization Initiator (F)>> Examples of polymerization initiators (F) include photopolymerization initiators and thermal polymerization initiators. Preferably, the polymerization initiator includes a photopolymerization initiator.

[0099] Examples of photopolymerization initiators include: halogenated hydrocarbon derivatives (e.g., compounds with a triazine skeleton, compounds with an oxadiazole skeleton, compounds with a trihalomethyl skeleton, etc.), acylphosphine compounds such as acylphosphine oxides, hexaaryl diimidazoles, oxime compounds such as oxime derivatives, organic peroxides, thio compounds, ketone compounds, aromatic onium salts, ketoxime ethers, aminoacetophenone compounds, hydroxyacetophenone, azo compounds, azido compounds, metallocene compounds, organoboron compounds, iron aromatic complexes, and other known compounds.

[0100] Polymerization initiators (F) can be used alone or in combination.

[0101] The content of polymerization initiator (F) in the resin composition (preferably the content of photopolymerization initiator) is based on the total mass of the solid components of the resin composition after removing the white pigment, and is preferably 5% or more by mass, 10% or more by mass, or 15% or more by mass, and is also preferably 30% or less by mass, 25% or less by mass, or 20% or less by mass.

[0102] <<Other Ingredients (G)>> Other components, without impairing the effects of the present invention, include: crosslinking agents, crosslinking aids, defoamers, rust inhibitors, catalysts (reaction catalysts for epoxy resins, thermosetting catalysts), antioxidants, leveling agents, inorganic fillers such as silica, sensitizers, adhesive aids, surfactants, plasticizers, flame retardants, cellulose nanofibers, dispersants, adhesiveness enhancers, and other additives.

[0103] In addition, the resin composition (G) may also contain organic solvents as other components. Examples of organic solvents include: ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetates such as ethyl acetate, butyl acetate, acetic acid cellosolve, propylene glycol monomethyl ether acetate, and carbitol acetate; cellosolves such as butyl cellosolve; carbitols such as carbitol and butyl carbitol; aromatics such as toluene and xylene; and other organic solvents such as dimethylformamide and dimethylacetamide.

[0104] Other ingredients (G) may be used alone or in combination of two or more.

[0105] In addition, the total content of other components (G) in the resin composition (excluding organic solvents) is preferably 1% or more, 5% or more, or 10% or more by mass, based on the total mass of the solid components of the resin composition after removing the white pigment. It is also preferably 40% or less, 30% or less, or 20% or less by mass.

[0106] In white solder resists, a high proportion of white pigments such as titanium dioxide can be added to achieve high reflectivity. In this case, a large amount of white pigment may also be present near the surface of the cured product. It is known that, due to the large amount of white pigment on the surface of the cured product, there is a possibility of scratching items that come into contact with the cured product (clamps, metal conveyor belts, etc.), and contact marks from these items are more likely to remain on the cured product side, thus easily resulting in defective products. The ability to resist the occurrence of such contact marks is called scratch resistance. According to the resin composition disclosed herein, by including white pigment (D) as a component of the resin composition, it is combined with an alkali-soluble polymer (A), a urethane polymer (B), and a mercaptan-containing compound (C). The cyclohexyl group derived from the alkali-soluble polymer (A) helps to improve hydrophobicity, compatibility between components, and also provides developability. Furthermore, by using the urethane polymer (B) in combination, the resulting cured product can be given flexibility. Additionally, by including the mercaptan-containing compound (C), it can react rapidly with other polymerizable components, and impart surface curing properties to the resulting cured product. Furthermore, it is known that the cured product obtained using the resin composition disclosed herein has a lower white pigment (D) concentration compared to conventionally known cured products. While the reason for this is uncertain, it is considered that by improving photocurability and developability, titanium dioxide is less likely to be exposed during development; and by using urethane polymers to induce swelling, it tends to remain as a film on the titanium dioxide surface. Therefore, it is speculated that the resin composition containing the alkali-soluble polymer (A), urethane polymer (B), and thiol-containing compound (C), even when containing (especially in high amounts) white pigment (D), can yield a cured product with excellent scratch resistance, low warpage, and undercut performance. Additionally, according to the resin composition disclosed herein, by including these components, discoloration during reflow soldering can be suppressed. It is further speculated that by including the thermosetting resin (E) and polymerization initiator (F), the resin composition improves reactivity and curability, thereby further enhancing the above-mentioned effects. When using the resin composition disclosed herein to form a cured product, it can be treated in the same way as other solder resists. Furthermore, since the cured material has minimal impact when in contact with other items (clamps, metal conveyor belts, etc.) (the arrangement of the surface with the cured material has minimal influence), the same processing can be performed whether the cured material is on one side or both sides. As a result, the cured material formed using the resin composition disclosed herein is easy to handle and can improve production efficiency.

[0107] The resin composition disclosed herein can be manufactured, for example, by mixing the raw materials simultaneously or sequentially and kneading them appropriately using conventionally known methods. Alternatively, the raw materials can be prepared in advance as solutions or dispersions before mixing.

[0108] <<<Uses / Applications of Resin Compositions>>> The following describes the use / method of using the resin composition, including the dry film obtained by using the resin composition and the cured product obtained by using the resin composition.

[0109] <<Dry Film>> The dry film has a resin layer obtained by applying the resin composition of the present disclosure to at least one side of a first film (substrate film) and then drying it. The dry film is used by laminating the resin layer to the substrate.

[0110] A resin composition is uniformly coated onto a first film using a suitable method such as a doctor blade coater, lip coater, comma coater, or thin film coater, and then dried to form the aforementioned resin layer, thereby enabling the manufacture of a dry film. Preferably, a second film (protective film) is laminated onto the resin layer. The first and second films can be made of the same film material or different film materials.

[0111] The membrane materials used for the first and second membranes can be any known materials that can be used for dry membranes.

[0112] As the first membrane, thermoplastic films such as polyethylene terephthalate (PET) films with a thickness of 2-150 μm can be used.

[0113] As the second membrane, polyethylene membrane, polypropylene membrane, etc. can be used, but it is preferable that the adhesion to the resin layer is smaller than that of the first membrane.

[0114] The thickness of the resin layer on the first membrane is preferably less than 100 μm, and more preferably in the range of 5-50 μm.

[0115] <<Cured product>> Cured products can be obtained by using the resin composition disclosed herein or a dry film having a resin layer obtained from the resin composition disclosed herein. The following describes methods for manufacturing cured products and their uses.

[0116] <Method for manufacturing solidified products> The following is an example of a method for manufacturing a cured product according to the present disclosure, which describes a method of using the resin composition according to the present disclosure as a photosensitive resin composition (a resin composition containing a component having photosensitive parts) in a negative photolithography process to manufacture a patterned film as a cured product of the resin composition according to the present disclosure.

[0117] First, as step 1, a resin layer is formed by coating a resin composition onto a substrate and drying it. Alternatively, in the case of a dry film, the resin layer is bonded to the substrate in contact with the substrate by means of lamination or the like, thereby forming a resin layer on the substrate.

[0118] As a method for coating a resin composition onto a substrate, conventional methods for coating resin compositions can be used, such as coating methods using spin coaters, bar coaters, doctor blade coaters, curtain coaters, screen printing machines, etc., spray coating methods using spray coaters, and further methods using inkjet printing, etc.

[0119] Furthermore, the method for laminating the dry film onto the substrate is preferably performed using a vacuum laminator or similar device under pressure and heat. By using such a vacuum laminator, even if the surface of the circuit board has irregularities, the dry film adheres tightly to the board, preventing air bubbles from entering, and also improving the filling performance of recesses on the board surface. The pressure conditions are preferably between 0.1 and 2.0 MPa, and the heating conditions are preferably between 40 and 120°C.

[0120] As a drying method after coating the resin composition, methods such as air drying, oven drying or heating with a hot plate, and vacuum drying are used. In addition, the drying conditions are not particularly limited, but natural drying, air drying, or heating drying can be carried out at 60-130°C for 1-30 minutes.

[0121] The substrate on which the resin layer is formed is not particularly limited. In addition to printed wiring boards and flexible printed wiring boards that have circuits formed in advance with copper, examples include: paper-based phenolic resin, paper-based epoxy resin, glass cloth epoxy resin, glass cloth polyimide, glass cloth / non-woven epoxy resin, glass cloth / paper-based epoxy resin, synthetic fiber epoxy resin, fluororesin / polyethylene / polyphenylene ether, copper-clad laminates for high-frequency circuits using polyphenylene ether / cyanate, and copper-clad laminates of all grades (FR-4, etc.). Other materials include metal substrates, polyimide films, cyclic olefin polymer films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, and wafer boards.

[0122] Next, as step 2, the resin layer formed on the substrate is irradiated (exposed) with light using a patterned photomask or by direct patterning. Furthermore, when using a dry film, the first film is peeled off from the dry film after exposure. Alternatively, the resin layer exposed after peeling off the first film from the dry film can be exposed before exposure, provided it does not impair the properties. During exposure, any device equipped with a high-pressure mercury lamp, ultra-high-pressure mercury lamp, metal halide lamp, mercury short-arc lamp, etc., that irradiates ultraviolet light in the 350-450 nm range is acceptable. Furthermore, a direct drawing device (e.g., a laser direct imaging device that directly draws an image using laser light from CAD data from a computer) can also be used. The light source or laser source used in the direct drawing device can be any light source with a maximum wavelength in the 350-450 nm range. Although the exposure amount varies depending on the film thickness, it is generally in the range of 10-1000 mJ / cm², preferably in the range of 20-800 mJ / cm².

[0123] Next, as step 3, the exposed resin layer is treated with a developing solution. This removes the unexposed portions of the resin, forming a patterned, cured film. After development, the resin layer can also be cleaned with a rinsing solution if necessary.

[0124] The developing method can be any of the following: immersion, spraying, misting, brushing, etc.

[0125] Examples of developing solutions include: inorganic bases such as sodium hydroxide, sodium carbonate, sodium silicate, and ammonia; organic amines such as ethylamine, diethylamine, triethylamine, and triethanolamine; and aqueous solutions of quaternary ammonium salts such as tetramethylammonium hydroxide and tetrabutylammonium hydroxide. Additionally, water-soluble organic solvents such as methanol, ethanol, and isopropanol, as well as surfactants, can be added to these components as needed. Afterward, the coating is rinsed with a rinsing solution as required to obtain a patterned film. Distilled water, methanol, ethanol, and isopropanol can be used alone or in combination as rinsing solutions. Furthermore, the aforementioned solvents can also be used as developing solutions.

[0126] Additionally, as needed, step 4 can further involve irradiating the patterned curing film with active energy lines followed by heat curing, or heat curing followed by irradiation with active energy lines, or simply heat curing to achieve final curing (formal curing). The heating temperature is not particularly limited; for example, it can be heated at 100-220°C for 30-120 minutes. The ambient atmosphere (gas) can be air, or inert gases such as nitrogen or argon.

[0127] <Uses of cured products> The cured product disclosed herein can be used in various electronic components including printed wiring boards. Due to its excellent reflectivity and low rate of defective products, the cured product disclosed herein is preferably used as a mounting substrate for light-emitting elements.

[0128] Figure 1 This is an example of a light-emitting element mounting substrate 100 (light-emitting device). More specifically, Figure 1 A top-view conceptual diagram showing a portion of the light-emitting element mounting substrate 100. (See diagram below.) Figure 1 As shown, the light-emitting element mounting substrate 100 includes: a substrate 10; a circuit (not shown) disposed on the substrate 10; a reflective layer 11 disposed in a manner that covers the circuit; and a plurality of light-emitting elements 12 mounted on the substrate 10.

[0129] The light-emitting element 12 is, for example, a light-emitting diode.

[0130] The reflective layer 11 is a white solder resist formed from a cured product of the resin composition disclosed herein. While protecting the circuit, the reflective layer 11 efficiently reflects light irradiated from the light-emitting element 12 to the front (top), thereby improving luminous efficiency. Furthermore, the reflective layer 11 exhibits excellent scratch resistance, making it less likely to scratch items in contact with the light-emitting element mounting substrate 100. Additionally, the reflective layer 11, as a cured product of the resin composition disclosed herein, possesses excellent low warpage and undercut properties, thereby improving the reliability of the light-emitting element mounting substrate 100.

[0131] In addition, Figure 1 In this embodiment, the light-emitting element mounting substrate 100 has a plate-like structure, but at least part or all of the light-emitting element mounting substrate 100 may also have a curved or bent structure, or it may also be a flexible wiring substrate. In addition, the density of the light-emitting elements 12, the distance between the light-emitting elements 12, and other arrangements of the light-emitting elements 12 can be freely changed as appropriate.

[0132] Example <<<Preparation of Resin Compositions>>> The resin compositions described below were prepared using the raw materials shown in Table 1, in the mixing amounts shown. Table 1 shows the content (parts by mass) of the solid components of each raw material.

[0133] <<Alkali-soluble polymers containing cyclohexyl and carboxyl groups (A)>> <A1> A base-soluble polymer (A) containing cyclohexyl and carboxyl groups is manufactured under the following conditions.

[0134] In a four-necked flask equipped with a reflux condenser, thermometer, nitrogen-purged glass tube, and stirrer, 223.8 parts by weight (2.6 mol) of methacrylic acid, 100.1 g (1.0 mol) of methyl methacrylate, 246.7 parts by weight (1.6 mol) of cyclohexyl acrylate, 1400 parts by weight of dipropylene glycol methyl ether, and 16.4 parts by weight (0.1 mol) of azobisisobutyronitrile were added. The mixture was heated at 75°C for 5 hours under a nitrogen atmosphere to carry out the polymerization reaction. After adding 17.0 parts by weight (0.07 mol) of triphenylphosphine, 156.4 parts by weight (1.1 mol) of glycidyl methacrylate were added, and the mixture was heated at 90-100°C for 6 hours to carry out the addition of acrylate groups. Triphenylphosphine was deactivated by air bubbling to obtain an alkali-soluble polymer (A1) containing cyclohexyl and carboxyl groups (solid component acid value: 110 mg KOH / g, solid component concentration: 35% by mass, weight-average molecular weight Mw: 15000, acrylic acid equivalent: approximately 800, cyclohexyl equivalent: approximately 500).

[0135] <<Carbamate Polymer (B)>> <B1> The urethane polymer (B1) is manufactured under the following conditions.

[0136] In a reaction vessel equipped with a stirrer, thermometer, and condenser, 360 g (0.45 mol) of polycarbonate diol (number average molecular weight 800) derived from 1,5-pentanediol and 1,6-hexanediol, 81.4 g (0.55 mol) of dimethylolbutyric acid, and 22.1 g (0.16 mol) of hydroxyphenylethanol, a compound having one alcoholic hydroxyl group and one or more phenolic hydroxyl groups per molecule, were added.

[0137] Next, as a compound having an isocyanate group not directly attached to the aromatic ring, 200.9 g (1.08 mol) of trimethylhexamethylene diisocyanate was added. The mixture was heated to 60 °C while stirring, and then the heating was stopped. When the temperature inside the reaction vessel began to drop, the mixture was heated again and stirred continuously at 80 °C. The reaction was terminated after the absorption peak (2280 cm⁻¹) of the isocyanate group disappeared, as confirmed by infrared absorption spectroscopy.

[0138] Subsequently, carbitol acetate was added to make the solids content 50 wt%, resulting in a carboxyl-containing urethane polymer (B1).

[0139] The obtained urethane polymer (B1) has an acid value of 48.8 mg KOH / g, a carboxylic acid equivalent of 1200, and a weight-average molecular weight of 16000.

[0140] <B2> Carbamate polymers Product Name: ART RESIN UN-3320HA (manufactured by Nejou Kogyo Co., Ltd.)

[0141] <<Thiol-containing compounds (C)>> <C1> Thiol-modified acrylates Product Name: ADDITOL LED 01 (manufactured by Daicel Co., Ltd.)

[0142] <C2> Secondary polyfunctional thiols Product name: KarenzMT PE1 (manufactured by Lisennoco).

[0143] <<White Pigment (D)>> <D1> Titanium dioxide Product Name: TIPAQUE PFC107 (manufactured by Ishihara Sangyo Co., Ltd., average particle size D50=250nm).

[0144] <<Thermosetting Resins (E)>> <E1> Biphenyl-type phenolic epoxy resin Product Name: NC-3000H-CA75 (manufactured by Nippon Kayaku Co., Ltd.)

[0145] <E2> Biphenyl-based bifunctional epoxy resin Product Name: YX-4000 (Manufactured by Mitsubishi Chemical Corporation, pulverization grade).

[0146] <<Polymerization Initiator (F)>> <F1> Acylphosphine-based photopolymerization initiators Product Name: Omnirad TPO H (manufactured by Omnirad Resins Pte Ltd).

[0147] <F2> Oxime ester photopolymerization initiators Product Name: Irgacure OXE04 (manufactured by BASF Japan Co., Ltd.)

[0148] <<Other Ingredients (G)>> <G1> Crosslinking agent EO9 Bisphenol A dimethacrylate Product Name: BPE-900 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0149] <<<Evaluation>>> For the resin compositions involved in each embodiment and comparative example, reflectivity, scratch resistance, low warpage, undercut resistance, and reflow soldering colorfastness were evaluated based on the following evaluation methods. The evaluation results are shown in Table 1.

[0150] <<Substrate Fabrication Conditions>> The substrate should be fabricated under the following conditions.

[0151] A copper-clad laminate (ESPANEX; manufactured by Nippon Steel Chemical Materials Co., Ltd.; double-sided product with 12 μm copper thickness and 25 μm polyimide thickness) with a thickness of 50 μm and a size of 150 mm × 100 mm was cleaned with sulfuric acid and hydrogen peroxide. Then, the resin compositions of Examples 1-4 and Comparative Examples 1-5 were coated using a 100-mesh screen printing plate to a film thickness of 20 μm, and dried at 70°C for 30 minutes in a hot air circulating drying oven. Afterwards, exposure was performed using an exposure machine equipped with a high-pressure mercury lamp (short arc lamp) at a cumulative exposure dose of 500 mJ / cm². Finally, formal curing was performed by heating at 150°C for 60 minutes in a hot air circulating drying oven to obtain the test substrate.

[0152] <<Reflectivity>> For the test substrates obtained by the above method, the Y value (%) in the XYZ color system at a wavelength of 450 nm was measured using a spectrophotometer (CM-2600d, manufactured by Konica Minolta) in the SCI mode (including specular reflection) to serve as the reflectance.

[0153] (Evaluation Benchmark) A (Excellent): Reflectivity is above 87%.

[0154] B (Good): Reflectivity is above 84% but less than 87%.

[0155] C (Unacceptable): Reflectivity less than 84%.

[0156] <<Scratch Resistance>> Scratch resistance is used to assess the ease with which defects are produced.

[0157] On the obtained test substrate, a double-sided copper-clad flexible substrate (a substrate with copper foil on both sides of a 100mm × 100mm polyimide film of 18μm thickness) was placed. A circular, flat-bottomed weight (1kg) with a diameter of 12mm was then placed on top of the substrate. In this state, the double-sided copper-clad flexible substrate was pulled approximately 10cm parallel to the surface within 10 seconds. The presence of black marks on the coating was evaluated according to the following criteria.

[0158] (Evaluation Benchmark) A (Excellent): No contact marks (black lines) appeared after more than 5 tests.

[0159] B (Good): Contact marks (black lines) appear after 2-4 tests.

[0160] C (Fail): Contact marks (black lines) appear after only one test.

[0161] <<Low Warp>> The obtained test substrate was cut into 50mm × 50mm pieces and placed on a cutting pad at room temperature. The warpage at the four corners was calculated. The test was conducted with n=5, and the average value was calculated and evaluated according to the following criteria.

[0162] (Evaluation Benchmark) A (Excellent): Warpage less than 1mm.

[0163] B (Good): Warpage is 1mm or more but less than 4mm.

[0164] C (Unacceptable): Warping is 4mm or more.

[0165] <<Undercut>> A copper-clad laminate (ESPANEX; manufactured by Nippon Steel Chemical Materials Co., Ltd.; double-sided product with a copper thickness of 12 μm and a polyimide thickness of 25 μm) with conductor circuits formed at L / S intervals of 10 μm / 10 μm to 20 μm / 20 μm to 100 μm / 100 μm was subjected to sulfuric acid-hydrogen peroxide cleaning treatment. Then, the resin compositions of Examples 1-4 and Comparative Examples 1-5 were coated with a 100-mesh screen printing plate with a film thickness of 20 μm and dried at 70°C for 30 minutes in a hot air circulating drying oven. Subsequently, an exposure machine equipped with a high-pressure mercury lamp (short arc lamp) was used to expose the substrate at a cumulative exposure dose of 500 mJ / cm², forming patterns with L / S intervals ranging from 20 μm / 20 μm to 100 μm / 100 μm. Afterward, the substrate was formally cured at 150°C for 60 minutes in a hot air circulating drying oven to obtain the substrate for undercut testing.

[0166] The line width of the obtained undercut test substrate was calculated and measured using an optical microscope (DIGITAL MICROSCOPE VHX-6000, manufactured by Keyence) at a measurement magnification of 500x, and evaluated according to the following criteria.

[0167] (Evaluation Benchmark) A (Excellent): A 50μm line remains on the substrate used for the undercut test.

[0168] B (Good): Although there are no 50μm lines remaining on the substrate used for the undercut test, there are 60μm lines remaining.

[0169] C (Failure): No 60μm lines remain on the substrate used for the undercut test.

[0170] <<Reflow Soldering Discoloration Resistance>> For the obtained test substrates, a reflow soldering device (manufactured by Hachi Machinery Co., Ltd., NIS-20-82S) was used to perform 1-5 reflow soldering processes in an air atmosphere, maintaining a peak temperature of 260°C for 60 seconds, and the discoloration was evaluated by visual observation.

[0171] (Evaluation Benchmark) A (Excellent): No discoloration after 5 reflow soldering cycles.

[0172] B (Good): No color change after 3 reflow soldering cycles, but color change after 4 reflow soldering cycles.

[0173] C (Unacceptable): Discoloration occurs after 1-3 reflow soldering cycles.

[0174] [Table 1]

[0175] Industrial utilization The resin composition disclosed herein can produce a white solder resist with high reflectivity and low defect rate. Therefore, the resin composition disclosed herein is preferably used for manufacturing various electronic components (especially light-emitting element mounting substrates) including printed wiring boards.

[0176] Cross-reference to related applications This application claims priority based on Japan Patent Application No. 2023-187237, filed with the Japan Patent Office on October 31, 2023, the entire disclosure of which is incorporated herein by reference.

Claims

1. A resin composition, characterized in that, Include: Alkali-soluble polymers containing cyclohexyl and carboxyl groups (A); Carbamate polymer (B); Compounds containing thiol groups (C); and White pigment (D).

2. The resin composition according to claim 1, wherein, The white pigment (D) contains titanium dioxide.

3. The resin composition according to claim 1, wherein, The urethane polymer (B) contains a carboxyl group.

4. The resin composition according to claim 1 or 2, wherein, When the total mass of the alkali-soluble polymer (A), the urethane polymer (B), and the compound (C) is 100 parts by mass, the content of the white pigment (D) is 200-500 parts by mass in terms of solid components.

5. The resin composition according to claim 1 or 2, wherein, It contains a polymerization initiator.

6. A dry film, characterized in that, The resin composition according to claim 1 is coated onto the first film to obtain the product.

7. A cured product, characterized in that, It is obtained using the resin composition according to claim 1 or the dry film according to claim 6.

8. A light-emitting element mounting substrate, characterized in that, It has the cured product as described in claim 7.

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