Structure, electronic part, and display

Abstract

To provide a structure that uses a white support which is not a metal substrate, improves a reflectance of the support itself, and can realize a thin and lightweight display without impairing a luminance of the display.SOLUTION: A structure according to the present invention comprises: a white support formed by using a curable resin composition containing a white colorant; and a white resin layer formed by using a curable resin composition containing a white colorant and provided on the white support.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a structure, an electronic component, and a display. [Background technology]

[0002] In the past, in order to improve the brightness of displays and reduce power consumption, it has been considered to form a highly reflective layer around light-emitting elements on a substrate. In recent years, there has been a demand for higher reflectance in order to further reduce power consumption and improve brightness. For example, Patent Document 1 proposes using a metal plate made of a metal such as aluminum as the substrate. Patent Document 2 proposes providing a solder resist layer on a substrate, the solder resist layer including a layer made of a white alkali-developable photosensitive resin composition and a layer made of a white thermosetting resin composition provided so as to be superimposed on the layer, in order to improve reflectance.

[0003] There is also a demand for thinner and lighter displays, and the use of films and prepregs for substrates is being considered. For example, Patent Document 3 proposes a film-based white substrate having a resin layer and a metal layer, in that order, on at least one side of an organic insulating film, and the resin layer is made up of a resin composition that contains at least one type of (A) thermoplastic resin, (B) epoxy resin, and (C) white particles. Furthermore, Patent Document 4 proposes a white substrate that contains a cured transparent resin, glass fibers, and a light-scattering filler and has a light reflectance of 70% or more at a wavelength of 550 nm. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-228137 A [Patent Document 2] JP 2011-49476 A [Patent Document 3] JP 2011-5714 A [Patent Document 4] JP 2012-177877 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the circuit boards described in Patent Documents 1 and 2 leave room for improvement in terms of making displays thinner and lighter. In addition, for the white substrates described in Patent Documents 3 and 4, although the reflectance of the substrate itself has been examined, there is still room for improvement in the reflectance when used as a backlight substrate from the viewpoints of further improving the brightness of the display and saving power.

[0006] Therefore, an object of the present invention is to provide a structure that uses a white support instead of a metal substrate, and that can realize a thin and lightweight display without impairing the brightness by forming a white resin layer on the white support while improving the reflectance of the support itself. Another object of the present invention is to provide an electronic component including the structure and a display including the electronic component. [Means for solving the problem]

[0007] As a result of intensive research into achieving the above-mentioned object, the inventors have discovered that by using a white support that is not a metal substrate and improving the reflectance of the support itself while forming a white resin layer on the white support, the above-mentioned problem can be solved by making the display thinner and lighter without impairing its brightness, and have thus completed the present invention.

[0008] That is, according to the present invention, the following inventions are provided. [1] A white support formed using a curable resin composition containing a white colorant; a white resin layer formed by using a curable resin composition containing a white colorant provided on the white support; A structure comprising: [2] The structure according to [1], wherein the white colorant contains titanium oxide. [3] The structure according to [1] or [2], wherein the white support is a resin film formed from the curable resin composition. [4] The structure according to [1] or [2], wherein the white support is a prepreg formed by impregnating a fiber base material with the curable resin composition. [5] The structure according to any one of [1] to [4], which is a circuit board having a plurality of electrodes arranged at predetermined intervals on the white support. [6] The structure described in [5], wherein the white resin layer has a plurality of openings in the upper region of the electrodes of the circuit board. [7] The structure according to [6], further comprising a light-emitting element mounted in the opening. [8] An electronic component comprising the structure according to any one of [1] to [7]. [9] A display comprising the electronic component described in [8]. Effect of the Invention

[0009] According to the present invention, a structure can be provided that can realize a thin and lightweight display without impairing the brightness by using a white support that is not a metal substrate and forming a white resin layer on the white support while improving the reflectance of the support itself. Also, according to the present invention, an electronic component including the structure and a display including the electronic component can be provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Structure] The structure of the present invention includes a white support formed using a curable resin composition containing a white colorant, and a white resin layer formed on the white support using a curable resin composition containing a white colorant. The structure of the present invention uses a white support that is not a metal substrate, and while improving the reflectance of the support itself, a white resin layer is formed on the white support, thereby making it possible to realize a thinner and lighter display without impairing the brightness.

[0011] (white support) The white support is formed using a curable resin composition containing a white colorant, and can be used alone as a substrate for a circuit board. More specifically, the white support may be a resin film formed from a thermosetting resin composition, or a prepreg formed by impregnating a fiber substrate with the thermosetting resin composition. In the present invention, the white support excludes supports including a metal layer or a metal substrate.

[0012] (Curable resin composition for white support) The curable resin composition contains at least a curable resin and a white colorant, and may further contain a curing catalyst, a photopolymerization initiator, and other components.

[0013] (curable resin) The curable resin can be used without any particular limitation as long as it is a resin that is cured by the action of heat, light, or the like. Specifically, a thermosetting resin, a photocurable resin, or the like can be used. The curable resin may be used alone or in combination of two or more. For example, a thermosetting resin or a photocurable resin may be used alone or in combination, but it is preferable to include a photocurable resin.

[0014] (thermosetting resin) Any known thermosetting resin can be used as the thermosetting resin. The curable resin composition contains a thermosetting resin, thereby improving the heat resistance of the cured coating film. As the thermosetting resin, for example, known thermosetting resins such as amino resins such as melamine resins, benzoguanamine resins, melamine derivatives, and benzoguanamine derivatives, isocyanate compounds, blocked isocyanate compounds, cyclocarbonate compounds, epoxy compounds, oxetane compounds, episulfide resins, bismaleimide, and carbodiimide resins can be used. Particularly preferred is a thermosetting resin having a plurality of cyclic ether groups or cyclic thioether groups (hereinafter abbreviated as cyclic (thio)ether groups) in the molecule. The thermosetting resin can be used alone or in combination of two or more types.

[0015] The thermosetting resin having a plurality of cyclic (thio)ether groups in the molecule is a compound having a plurality of 3-, 4-, or 5-membered cyclic (thio)ether groups in the molecule, and examples thereof include a compound having a plurality of epoxy groups in the molecule, i.e., a polyfunctional epoxy resin, a compound having a plurality of oxetanyl groups in the molecule, i.e., a polyfunctional oxetane compound, and a compound having a plurality of thioether groups in the molecule, i.e., an episulfide resin.

[0016] Examples of such epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, brominated bisphenol A type epoxy resins, bisphenol S type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, biphenyl type epoxy resins, naphthalene type epoxy resins, dicyclopentadiene type epoxy resins, triphenylmethane type epoxy resins, and the like.

[0017] Examples of commercially available epoxy resins include jER 828, 806, 807, YX8000, YX8034, and 834 manufactured by Mitsubishi Chemical Corporation; YD-128, YDF-170, ZX-1059, and ST-3000 manufactured by Nippon Steel Chemical & Material Co., Ltd.; EPICLON 830, 835, 840, 850, N-730A, and N-695 manufactured by DIC Corporation; and RE-306 manufactured by Nippon Kayaku Co., Ltd.

[0018] Examples of the polyfunctional oxetane compound include bis[(3-methyl-3-oxetanylmethoxy)methyl]ether, bis[(3-ethyl-3-oxetanylmethoxy)methyl]ether, 1,4-bis[(3-methyl-3-oxetanylmethoxy)methyl]benzene, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, (3-methyl-3-oxetanyl)methyl acrylate, and (3-ethyl-3-oxetanyl)methyl acrylate. Examples of the oxetanes include polyfunctional oxetanes such as acrylate, (3-methyl-3-oxetanyl)methyl methacrylate, (3-ethyl-3-oxetanyl)methyl methacrylate, and their oligomers or copolymers, as well as ethers of oxetane alcohols and novolac resins, poly(p-hydroxystyrene), cardo-type bisphenols, calixarenes, calixresorcinarenes, or resins having hydroxyl groups such as silsesquioxane. Other examples include copolymers of unsaturated monomers having an oxetane ring and alkyl (meth)acrylates.

[0019] Examples of compounds having multiple cyclic thioether groups in the molecule include bisphenol A episulfide resins, etc. Using a similar synthesis method, episulfide resins in which the oxygen atoms of the epoxy groups of novolac epoxy resins are replaced with sulfur atoms can also be used.

[0020] Examples of amino resins such as melamine derivatives and benzoguanamine derivatives include methylolmelamine compounds, methylolbenzoguanamine compounds, methylolglycoluril compounds, and methylolurea compounds.

[0021] The isocyanate compound may be a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, o-xylylene diisocyanate, m-xylylene diisocyanate, and 2,4-tolylene dimer; aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4-methylenebis(cyclohexyl isocyanate) and isophorone diisocyanate; alicyclic polyisocyanates such as bicycloheptane triisocyanate; and adducts, biurets, and isocyanurates of the above-mentioned isocyanate compounds.

[0022] The blocked isocyanate compound may be an addition reaction product of an isocyanate compound and an isocyanate blocking agent. Examples of isocyanate compounds that can react with an isocyanate blocking agent include the polyisocyanate compounds described above. Examples of isocyanate blocking agents include phenol-based blocking agents, lactam-based blocking agents, active methylene-based blocking agents, alcohol-based blocking agents, oxime-based blocking agents, mercaptan-based blocking agents, acid amide-based blocking agents, imide-based blocking agents, amine-based blocking agents, imidazole-based blocking agents, and imine-based blocking agents.

[0023] The amount of the thermosetting resin is preferably 10% by mass or more and 60% by mass or less, more preferably 15% by mass or more and 50% by mass or less, and even more preferably 20% by mass or more and 40% by mass or less, calculated as a solid content based on the total amount of the curable resin composition. If the amount of the thermosetting resin is within the above numerical range, a free-standing film can be formed.

[0024] (light curing resin) The photocurable resin is a compound having an ethylenically unsaturated group, and may be a polymer, an oligomer, a monomer, or a mixture thereof. By including the photocurable resin, the strength of the cured film can be improved. The photocurable resin may be used alone or in combination of two or more kinds. In addition, the photocurable resin may be a carboxyl group-containing photosensitive resin described later.

[0025] As the compound having an ethylenically unsaturated group, a known and commonly used photopolymerizable oligomer, photopolymerizable monomer, etc. can be used. Among these, it is preferable to use a photopolymerizable monomer, since it can impart more crosslinking property and curing property to the cured coating film.

[0026] The photopolymerizable oligomer is an oligomer having an ethylenically unsaturated double bond. Examples of the photopolymerizable oligomer include unsaturated polyester oligomers and (meth)acrylate oligomers. Examples of the (meth)acrylate oligomer include epoxy (meth)acrylates such as phenol novolac epoxy (meth)acrylate, cresol novolac epoxy (meth)acrylate, and bisphenol type epoxy (meth)acrylate, urethane (meth)acrylate, epoxy urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, and polybutadiene modified (meth)acrylate.

[0027] The photopolymerizable monomer is a monomer having an ethylenically unsaturated double bond. Examples of such photopolymerizable monomers include alkyl (meth)acrylates such as 2-ethylhexyl (meth)acrylate and cyclohexyl (meth)acrylate; hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; mono- or di(meth)acrylates of alkylene oxide derivatives such as ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol; hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, and the like. Examples of the photopolymerizable monomer include polyhydric alcohols such as tris(hydroxyethyl)isocyanurate and the like, polyhydric (meth)acrylates of their ethylene oxide or propylene oxide adducts, (meth)acrylates of ethylene oxide or propylene oxide adducts of phenols such as phenoxyethyl (meth)acrylate and polyethoxy di(meth)acrylate of bisphenol A, (meth)acrylates of glycidyl ethers such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether and triglycidyl isocyanurate, and melamine (meth)acrylate. One type of photopolymerizable monomer may be used alone, or two or more types may be used in combination.

[0028] The amount of the photopolymerizable monomer is preferably 2% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 15% by mass or less, and even more preferably 4% by mass or more and 10% by mass or less, calculated as a solid content based on the total amount of the curable resin composition. When the amount of the photopolymerizable monomer is within the above numerical range, the photocurability is good.

[0029] The curable resin preferably contains an alkali-soluble resin having an alkali-soluble group, in that it can impart alkali developability to the curable resin composition. Examples of the alkali-soluble resin include a compound having two or more phenolic hydroxyl groups, a carboxyl group-containing resin, a compound having a phenolic hydroxyl group and a carboxyl group, and a compound having two or more thiol groups. Among them, a carboxyl group-containing resin or a phenolic resin is preferable because it improves adhesion to the base, and a carboxyl group-containing resin is more preferable because it is particularly excellent in developability. The carboxyl group-containing resin will be described below.

[0030] (Carboxyl group-containing resin) As the carboxyl group-containing resin, various conventionally known resins having a carboxyl group in the molecule can be used. The carboxyl group-containing resin may or may not have an ethylenically unsaturated double bond in the molecule, but in particular, a carboxyl group-containing photosensitive resin having an ethylenically unsaturated double bond in the molecule is preferred in terms of photocurability, development resistance, and resolution. When the curable resin composition of the present invention contains a carboxyl group-containing resin, it may be used not only for applications in which alkaline development is performed, but also for applications in which alkaline development is not performed. The ethylenically unsaturated double bond is preferably derived from acrylic acid or methacrylic acid or a derivative thereof. When only a carboxyl group-containing resin without an ethylenically unsaturated double bond is used, in order to make the composition photocurable, it is necessary to use a compound having a plurality of ethylenically unsaturated groups in the molecule, i.e., a photopolymerizable monomer, in combination as described above. Specific examples of the carboxyl group-containing resin include the following compounds (which may be either oligomers or polymers).

[0031] (1) Carboxyl group-containing resins obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with unsaturated group-containing compounds such as styrene, α-methylstyrene, lower alkyl (meth)acrylates, and isobutylene (lower alkyl (meth)acrylates include methyl (meth)acrylate, etc.).

[0032] (2) A carboxyl group-containing urethane resin obtained by polyaddition reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, etc., carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid, dimethylolbutanoic acid, and polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A-based alkylene oxide adduct diols, compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups, etc.

[0033] (3) A carboxyl group-containing photosensitive urethane resin obtained by polyaddition reaction of diisocyanates with (meth)acrylates of bifunctional epoxy resins such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin, etc. or their partial acid anhydride-modified products, carboxyl group-containing dialcohol compounds and diol compounds.

[0034] (4) A carboxyl group-containing photosensitive urethane resin with terminal (meth)acrylation, obtained by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as hydroxyalkyl (meth)acrylate, during the synthesis of the resin of (2) or (3) above.

[0035] (5) A carboxyl group-containing photosensitive urethane resin with terminal (meth)acrylation, obtained by adding a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate, during the synthesis of the resin of (2) or (3) above.

[0036] (6) A carboxyl group-containing photosensitive resin obtained by reacting a bifunctional or higher polyfunctional (solid) epoxy resin with (meth)acrylic acid and adding a dibasic acid anhydride to the hydroxyl groups present in the side chains.

[0037] (7) A carboxyl group-containing photosensitive resin obtained by reacting a multifunctional epoxy resin with the hydroxyl groups of a bifunctional (solid) epoxy resin further epoxidized with epichlorohydrin, with (meth)acrylic acid, and then adding a dibasic acid anhydride to the resulting hydroxyl groups.

[0038] (8) Carboxyl group-containing polyester resins obtained by reacting a dicarboxylic acid such as adipic acid, phthalic acid, or hexahydrophthalic acid with a bifunctional oxetane resin and then adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the resulting primary hydroxyl groups.

[0039] (9) A carboxyl group-containing photosensitive resin obtained by reacting an epoxy compound having multiple epoxy groups in one molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenethyl alcohol, and an unsaturated group-containing monocarboxylic acid, such as (meth)acrylic acid, and then reacting the alcoholic hydroxyl group of the resulting reaction product with a polybasic acid anhydride, such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, adipic acid, or the like.

[0040] (10) A carboxyl group-containing photosensitive resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide, reacting the reaction product obtained with an unsaturated group-containing monocarboxylic acid, and reacting the resulting reaction product with a polybasic acid anhydride.

[0041] (11) A carboxyl group-containing photosensitive resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate, reacting the reaction product obtained with an unsaturated group-containing monocarboxylic acid, and reacting the resulting reaction product with a polybasic acid anhydride.

[0042] (12) A carboxyl group-containing photosensitive resin obtained by further adding a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule to any one of the resins (1) to (11).

[0043] In this specification, (meth)acrylate is a term that collectively refers to acrylate, methacrylate, and mixtures thereof, and the same applies to other similar expressions.

[0044] The carboxyl group-containing resins that can be used in the present invention are not limited to those listed above. The carboxyl group-containing resins listed above may be used alone or in combination.

[0045] In the present invention, in consideration of the developability and drawing ability of the resist pattern when using a weak alkaline developer such as an aqueous sodium carbonate solution, the acid value of the carboxyl group-containing resin is preferably in the range of 30 to 150 mgKOH / g, more preferably in the range of 50 to 120 mgKOH / g. The higher the acid value of the carboxyl group-containing resin, the better the developability, but the exposed area is more likely to be dissolved by the developer, and the exposed area may be dissolved and peeled off by the developer without distinction between the exposed area and the unexposed area.

[0046] The weight average molecular weight of the carboxyl group-containing resin varies depending on the resin skeleton, but is generally in the range of 1,500 to 150,000, preferably in the range of 1,800 to 100,000. By using a carboxyl group-containing resin having a weight average molecular weight of 2,000 or more, it is possible to improve the resolution and tack-free performance. In addition, by using a carboxyl group-containing resin having a weight average molecular weight of 150,000 or less, it is possible to improve the developability and storage stability. The weight average molecular weight can be measured by gel permeation chromatography (GPC).

[0047] The amount of the carboxyl group-containing resin is, in terms of solid content, preferably 3% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 30% by mass or less, and even more preferably 10% by mass or more and 20% by mass or less, based on the total amount of the curable resin composition. If the amount of the carboxyl group-containing resin is within the above numerical range, the developability is good.

[0048] (White colorant) Examples of white colorants include titanium oxide, zinc oxide, potassium titanate, zirconium oxide, antimony oxide, white lead, zinc sulfide, lead titanate, silica, etc. These white colorants can be used alone or in combination of two or more.

[0049] (Titanium dioxide) Among the white colorants, titanium oxide is preferably used. Examples of titanium oxide include rutile titanium oxide and anatase titanium oxide, but in the present invention, rutile titanium oxide is preferably used. Anatase titanium oxide, which is the same titanium oxide, has a higher whiteness than rutile titanium oxide and is usually used as a white colorant. However, since anatase titanium oxide has photocatalytic activity, it may cause discoloration of the resin in the resin layer, especially due to light irradiated from an LED. On the other hand, although rutile titanium oxide has a slightly lower whiteness than anatase titanium oxide, it has almost no photoactivity, so that deterioration (yellowing) of the resin due to light caused by the photoactivity of titanium oxide is significantly suppressed, and it is also stable against heat. Therefore, when used as a white colorant in the resin layer of a connection structure in which an LED is mounted, high reflectance can be maintained for a long period of time.

[0050] Rutile titanium oxide may be a known one. There are two methods for producing rutile titanium oxide: the sulfuric acid method and the chlorine method. Either method may be used in the present invention. The sulfuric acid method is a method in which ilmenite ore or titanium slag is used as a raw material, which is dissolved in concentrated sulfuric acid to separate the iron content as iron sulfate, and the solution is hydrolyzed to obtain a hydroxide precipitate, which is then calcined at a high temperature to extract rutile titanium oxide. On the other hand, the chlorine method is a method in which synthetic rutile or natural rutile is used as a raw material, which is reacted with chlorine gas and carbon at a high temperature of about 1000°C to synthesize titanium tetrachloride, which is then oxidized to extract rutile titanium oxide. Among these, rutile titanium oxide produced by the chlorine method has a particularly remarkable effect in suppressing deterioration (yellowing) of resins due to heat, and is more preferably used in the present invention.

[0051] The rutile type titanium oxide may be a titanium oxide whose surface is treated with hydrous alumina, aluminum hydroxide, and / or silicon dioxide. By using the surface-treated rutile type titanium oxide, it is possible to improve dispersibility, storage stability, flame retardancy, etc. in the resin composition.

[0052] The average particle size of rutile-type titanium oxide is preferably 0.1 μm or more and 1.0 μm or less, more preferably 0.2 μm or more and 0.8 μm or less. In particular, it is preferable that rutile-type titanium oxide having a particle size of 0.25 μm is contained in 1% or more of the total particles. In this specification, the average particle size of rutile-type titanium oxide is the average particle size (D50) including not only the particle size of primary particles but also the particle size of secondary particles (aggregates), and is the value of D50 measured by laser diffraction method. As an example of a measuring device using the laser diffraction method, Microtrac MT3300EXII manufactured by Microtrac-Bell Co., Ltd. is mentioned. In addition, the average particle size of titanium oxide refers to the value measured as described above for the powder before preparing (pre-stirring, kneading) the curable resin composition.

[0053] Rutile titanium oxide may be a commercially available product. Examples of commercially available rutile titanium oxide include Typek R-820, Typek R-830, Typek R-930, Typek R-550, Typek R-630, Typek R-680, Typek R-670, Typek R-680, Typek R-670, Typek R-780, Typek R-850, Typek CR-50, Typek CR-57, Typek CR-80, Typek CR-90, and Typek 90. -2, Typek CR-93, Typek CR-95, Typek CR-97, Typek CR-63, Typek CR-58, Typek UT771 (manufactured by Ishihara Sangyo Co., Ltd.), Typek R-101, Typek R-103, Typek R-104, Typek R-105, Typek R-108, Typek R-900, Typek R-902+, Typek R-960, Typek R-706, (manufactured by DuPont Co., Ltd.), TITONE R-25, R-21, R-32, R-7E, R-5N, R-62N, R-42, R-45M, GTR-100, D-918 (manufactured by Sakai Chemical Industry Co., Ltd.), etc. can be used.

[0054] The amount of the white colorant is preferably 30% by mass or more and 90% by mass or less, more preferably 40% by mass or more and 80% by mass or less, and even more preferably 50% by mass or more and 70% by mass or less, calculated as a solid content based on the total amount of the curable resin composition. When the amount of the white colorant is within the above numerical range, the reflectance is good.

[0055] (curing catalyst) Examples of the curing catalyst include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; amine compounds such as dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, and 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; and phosphorus compounds such as triphenylphosphine. In addition, examples of commercially available compounds include 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, and 2P4MHZ (all trade names of imidazole-based compounds) manufactured by Shikoku Chemical Industry Co., Ltd., and U-CAT 3513N (a trade name of a dimethylamine-based compound), DBU, DBN, and U-CAT SA 102 (all bicyclic amidine compounds and their salts) manufactured by San-Apro Co., Ltd. In addition, S-triazine derivatives such as guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine·isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine·isocyanuric acid adduct can also be used, and preferably, compounds that also function as adhesion-imparting agents are used in combination with the heat curing catalyst. The thermosetting catalyst may be used alone or in combination of two or more kinds.

[0056] The amount of the curing catalyst is preferably 0.01% by mass or more and 2% by mass or less, more preferably 0.05% by mass or more and 1% by mass or less, and even more preferably 0.1% by mass or more and 0.5% by mass or less, calculated as a solid content based on the total amount of the curable resin composition. If the amount of the curing catalyst is within the above numerical range, the thermosetting property is good.

[0057] (Photopolymerization initiator) The photopolymerization initiator is for reacting the carboxyl group-containing photosensitive resin or the photopolymerizable monomer by exposure to light. Any known photopolymerization initiator can be used. The photopolymerization initiator may be used alone or in combination of two or more.

[0058] Specific examples of the photopolymerization initiator include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, 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, and bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentane. Bisacylphosphine oxides such as 2,6-dimethoxybenzoyldiphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloyl monoacylphosphine oxides such as phenylphosphinic acid isopropyl ester and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate, 1-hydroxy-cyclohexyl phenyl ketone, 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 benzoin, benzil, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether, and other benzoins; benzoin alkyl ethers; benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone, and other benzophenones;Acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone acetophenones such as acetophenone, N,N-dimethylaminoacetophenone; thioxanthones such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, Anthraquinones such as 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzil dimethyl ketal; benzoic acid esters such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, and p-dimethylbenzoic acid ethyl ester; 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetylacetone) oxime esters such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyrrol-1-yl)ethyl)phenyl]titanium, and other titanocenes; phenyl disulfide 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, tetramethylthiuram disulfide, and the like.

[0059] The amount of the photopolymerization initiator is preferably 0.01% by mass or more and 2% by mass or less, more preferably 0.05% by mass or more and 1% by mass or less, and even more preferably 0.1% by mass or more and 0.5% by mass or less, calculated as a solid content based on the total amount of the curable resin composition. When the amount of the photopolymerization initiator is within the above numerical range, the photocurability is good.

[0060] (Organic solvent) The curable resin composition may contain an organic solvent for the purpose of adjusting the viscosity when preparing the composition or when applying it to a support or film. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, and tripropylene glycol monomethyl ether; esters such as ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, diethylene glycol monoethyl ether acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha. Known and commonly used organic solvents can be used. These organic solvents may be used alone or in combination of two or more kinds.

[0061] The amount of the organic solvent to be added is not particularly limited, and can be appropriately set according to the target viscosity so as to facilitate the preparation of the curable resin composition.

[0062] (Other added ingredients) The thermosetting resin composition may further contain, as necessary, components such as cyanate compounds, elastomers, mercapto compounds, urethanization catalysts, thixotropic agents, adhesion promoters, block copolymers, chain transfer agents, polymerization inhibitors, copper inhibitors, antioxidants, rust inhibitors, thickeners, at least one of silicone-based, fluorine-based, and polymer-based defoamers and leveling agents, imidazole-based, thiazole-based, and triazole-based silane coupling agents, phosphinates, phosphate ester derivatives, and phosphorus compounds such as phosphazene compounds, and the like. These may be known in the field of electronic materials.

[0063] (Method for preparing curable resin composition) In preparing the curable resin composition, each component is weighed, mixed, and then pre-mixed with a mixer, and then each component is dispersed and kneaded with a kneader to prepare the curable resin composition.

[0064] Examples of the kneading machine include a bead mill, a ball mill, a sand mill, a three-roll mill, and a two-roll mill. Among these, it is preferable to use a bead mill in order to improve dispersibility. Dispersion conditions such as the type and particle size of the beads of the bead mill can be appropriately set according to the desired viscosity.

[0065] (Method of forming a white support) In one embodiment of a method for forming a white support, for example, the above-mentioned curable resin composition is molded into a film shape by a conventionally known method to form a white support (resin film).

[0066] In another embodiment of the method for forming the white support, for example, the above-mentioned curable resin composition is used to impregnate a fiber substrate by a conventional method, followed by curing, to form a white support (prepreg). The fiber substrate is not particularly limited, and examples thereof include inorganic fibers such as carbon fiber, silicon carbide fiber, and glass fiber, and organic fibers such as aramid fiber.

[0067] The thickness of the white support is not particularly limited, but is preferably 5 mm or less, more preferably 3 mm or less, and even more preferably 2 mm or less, and is preferably 0.05 mm or more, more preferably 0.08 mm or more, and even more preferably 0.1 mm or more. If the thickness of the white support is within the above range, the thickness of the entire mounting substrate can be reduced while maintaining its strength.

[0068] (Circuit board) The circuit board may be a white support on which a plurality of electrodes are arranged at a predetermined interval. The interval between the electrodes can be appropriately set depending on the size, application, etc. of the circuit board.

[0069] (white resin layer) The white resin layer is formed on the white support using a curable resin composition. The white resin layer may have a plurality of openings in the upper region of the electrode of the circuit board. A conventional light-emitting element can be mounted in the opening of the white resin layer. The shape of the opening of the resin layer as viewed from the top is not particularly limited, and examples thereof include quadrangles such as squares, rectangles, and trapezoids, polygons, ellipses, and circles, with a quadrangle being preferred. The quadrangle may also have rounded corners (rounded quadrangle).

[0070] (Curable resin composition for white resin layer) As the curable resin composition for the white resin layer, the same curable resin composition as the above-mentioned curable resin composition for the white support can be used.

[0071] (Method of forming white resin layer) In one embodiment of the method for forming the white resin layer, for example, the above-mentioned curable resin composition is applied to the above-mentioned white support by a conventionally known method, and then cured to form the white resin layer. The method for applying the curable resin composition is not particularly limited, and examples of the method include a screen printing method, a flow coating method, a roll coating method, a blade coating method, and a bar coating method.

[0072] The thickness of the white resin layer is not particularly limited, but is preferably 1 mm or less, more preferably 0.5 mm or less, even more preferably 0.1 mm or less, and is preferably 0.01 mm or more, more preferably 0.02 mm or more, even more preferably 0.03 mm or more. If the thickness of the white resin layer is within the above range, the thickness of the entire structure can be reduced while maintaining the strength.

[0073] [Electronic components] The electronic component of the present invention includes the above-mentioned structure. By using the structure of the present invention, it is possible to realize a thinner and lighter electronic component. The electronic component of the present invention is not particularly limited, and can be used, for example, in a mini-LED backlight of a liquid crystal monitor, a panel of a μ-LED display, etc. EXAMPLES

[0074] The present invention will be described in more detail below using examples, but the present invention is not limited to the following examples. In the following, "parts" and "%" are all based on mass unless otherwise specified.

[0075] (Carboxyl Group-Containing Resin 1 Synthesis Example 1) Into a reaction vessel equipped with a stirrer, a thermometer, and a condenser, 2400g (3 mol) of polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol (manufactured by Asahi Kasei Corporation, TJ5650J, number average molecular weight 800), 603g (4.5 mol) of dimethylolpropionic acid, and 238g (2.6 mol) of 2-hydroxyethyl acrylate as a monohydroxyl compound were added. Next, 1887g (8.5 mol) of isophorone diisocyanate was added as a polyisocyanate, and the mixture was heated to 60°C while stirring and stopped. When the temperature in the reaction vessel began to decrease, the mixture was heated again and continued to stir at 80°C. The reaction was terminated by confirming that the absorption spectrum (2280cm-1) of the isocyanate group disappeared in the infrared absorption spectrum. Carbitol acetate was added so that the solid content became 50% by mass, and a solution of carboxyl group-containing resin 1 having an acid value of 50 mgKOH / g of the solid content and a weight average molecular weight Mw of about 17,000 was obtained.

[0076] (Carboxyl Group-Containing Resin 2 Synthesis Example 2) 220 parts of cresol novolac epoxy resin (EPICLON N-695, epoxy equivalent: 220, manufactured by DIC Corporation) was placed in a four-neck flask equipped with a stirrer and a reflux condenser, and 214 parts of carbitol acetate was added and dissolved by heating. Next, 0.1 parts of hydroquinone as a polymerization inhibitor and 2.0 parts of dimethylbenzylamine as a reaction catalyst were added. This mixture was heated to 95-105°C, and 72 parts of acrylic acid were gradually added dropwise and reacted for 16 hours. This reaction product was cooled to 80-90°C, and 106 parts of tetrahydrophthalic anhydride was added, reacted for 8 hours, cooled, and then removed. In this way, a solution of carboxyl group-containing resin 2 was obtained having a solid content of 65%, an acid value of the solid content of 100 mgKOH / g, and a weight average molecular weight Mw of about 3,500. The weight average molecular weight of the resulting resin was measured by GPC.

[0077] <Preparation of Thermosetting Resin Composition for White Support> [Examples 1 to 7] The components were mixed according to the recipe shown in Table 1 below and dispersed using a triple roll mill to obtain the thermosetting resin compositions of Examples 1-7.

[0078] <Preparation of Curable Resin Composition for White Resin Layer> [Examples 1 to 7, Comparative Examples 1 to 2] The components were mixed according to the recipe shown in Table 2 below and dispersed using a three-roll mill to obtain thermosetting resin compositions of Examples 1-7 and Comparative Examples 1-2.

[0079] [Table 1]

[0080] [Table 2]

[0081] The blend amounts in Tables 1 and 2 are shown in parts by mass (solid content equivalent). Details of each component in Tables 1 and 2 are as follows. *1: Carboxyl group-containing resin 1 in Synthesis Example 1 *2: Carboxyl group-containing resin 2 from Synthesis Example 2 *3: jER834, manufactured by Mitsubishi Chemical Corporation *4: DICY7, manufactured by Mitsubishi Chemical Corporation *5: Diserbyk-111, manufactured by BYK Japan Co., Ltd. *6: KS-66, manufactured by Shin-Etsu Chemical Co., Ltd. *7: CR-90, manufactured by Ishihara Sangyo Kaisha, Ltd. *8: BPE-900, manufactured by Shin-Nakamura Chemical Co., Ltd. *9: 2,4,6-trimethylbenzoyldiphenylphosphine oxide

[0082] <How to fabricate the structure> [Examples 1 to 7] A thermosetting resin composition for a white support was applied onto a copper foil and heated at 150°C for 60 minutes to form a white cured film. The white cured film was then peeled off from the copper foil to obtain a white support having the thickness shown in Table 3. Copper foil was formed on the obtained white support by sputtering to form wiring. Next, a curable resin composition for a white resin layer was applied onto the white support on which the wiring was formed, and the white support was heated in a hot air circulation drying oven at 150°C for 60 minutes for Examples 1 to 4, 6, and 7 and Comparative Examples 1 and 2, and exposed to light at an exposure dose of 400 mJ / cm for Example 5. 2 After exposure to light at 400° C., the coating was cured by heating for 60 minutes at 150° C. in a hot air circulation drying oven to form a white resin layer having a thickness shown in Table 3, thereby obtaining a structure.

[0083] [Comparative Examples 1 to 2] Copper foil was formed on a metal substrate by sputtering to form wiring. Next, a curable resin composition for a white resin layer was applied onto the substrate on which the wiring was formed, and the substrate was heated at 150°C for 60 minutes in a hot air circulation drying oven for Examples 1 to 4, 6, and 7 and Comparative Examples 1 and 2, and exposed to 400 mJ / cm for Example 5. 2 After exposure to light at 400° C., the coating was cured by heating for 60 minutes at 150° C. in a hot air circulation drying oven to form a white resin layer having a thickness shown in Table 3, thereby obtaining a structure.

[0084] [Comparative Example 3] The white support obtained in Example 1 was used to form a structure without forming a white resin layer.

[0085] <Performance evaluation> <Reflectance> The reflectance at 450 nm of the white resin layer side of the structure produced above was measured using a spectrophotometric colorimeter CM-5. The reflectance was evaluated according to the following criteria. (Evaluation Criteria) ⊚: Reflectance was 93% or more. ◯: Reflectance was greater than 90% and less than 93%. ×: The reflectance was 90% or less.

[0086] <Pencil hardness> The pencil hardness of the white resin layer side of the structure produced above was measured in accordance with JIS-K5600-5-4:1999, and the highest pencil hardness that did not cause scratches on the white resin layer was taken as the pencil hardness. The pencil hardness was evaluated according to the following criteria. Note that the structure of Comparative Example 3 did not have a white resin layer formed thereon, so the pencil hardness was not measured (indicated as "-" in Table 3). (Evaluation Criteria) ⊚: Pencil hardness was 4H or more. ◯: Pencil hardness was 3H. ×: The pencil hardness was 2H or less.

[0087] The above evaluation results are shown in Table 3.

[0088] [Table 3]

Claims

1. A white support formed using a curable resin composition containing a white colorant; a white resin layer formed by using a curable resin composition containing a white colorant provided on the white support; A structure comprising:

2. The structure of claim 1 , wherein the white colorant comprises titanium dioxide.

3. The structure according to claim 1 , wherein the white support is a resin film formed from the curable resin composition.

4. The structure according to claim 1 , wherein the white support is a prepreg formed by impregnating a fiber base material with the curable resin composition.

5. 2. The structure according to claim 1, which is a circuit board having a plurality of electrodes arranged at predetermined intervals on the white support body.

6. The structure according to claim 5 , wherein the white resin layer has a plurality of openings in the upper regions of the electrodes of the circuit board.

7. The structure of claim 6 further comprising a light emitting element mounted in the opening.

8. An electronic component comprising the structure according to any one of claims 1 to 7.

9. A display comprising the electronic component according to claim 8.

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