Layered structure, cured product of a resin layer in the layered structure, electronic component, and method for forming a cured product

Abstract

[Problem] To provide a laminate in which both the peelability and the adhesiveness of a resin layer to a second film are good under conditions in which the ambient temperature of the periphery of the laminate rises to a certain temperature (particularly, around 40°C), a cured product of the resin layer in the laminate, an electronic component having the cured product, and a method for forming the cured product. [Solution] A laminate comprising, in this order, a first film, a resin layer, and a second film, the resin layer comprising: (A) an alkali-soluble resin, (B) a multifunctional photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting resin, the peel strength of the second film to the resin layer at an ambient temperature of 40°C being 0.4 to 1.5 N / cm.

Description

Technical Field

[0001] This invention relates to a laminated structure, a cured resin layer thereof, an electronic component having the cured resin, and a method for forming the cured resin. In particular, this invention relates to a laminated structure exhibiting good peelability and adhesion between the resin layer and a second film, a cured resin layer thereof, an electronic component having the cured resin, and a method for forming the cured resin. Background Technology

[0002] An insulating film (solder resist layer) is formed on printed circuit boards used in various electronic devices. This insulating film is formed, for example, by using a laminated structure comprising a first thin film, a resin layer, and a second thin film in sequence. A method for forming the insulating film based on this laminated structure includes a step of peeling the second thin film from the laminated structure; after this step, an insulating film is finally formed on a substrate on which circuitry is formed.

[0003] Compared with the adhesive sheet with protective film disclosed in Reference 1, which defines the relationship between the peel strength of the protective film (second film) relative to the resin composition layer and the peel strength of the support (first film) relative to the resin composition layer.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-123331 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, in the case of the adhesive sheet with a protective film described in Patent Document 1, the peel strength is low. Therefore, when the adhesive sheet is rolled up, there is a concern that it may become prone to wrinkling due to misalignment during winding. In other words, there is still a problem regarding the adhesion between the resin layer and the second film (inadequate peel strength).

[0009] Furthermore, for laminated structures, considering the process of peeling the second film from the laminated structure, good peelability between the resin layer and the second film is required. On the other hand, good adhesion between the resin layer and the second film is also required (e.g., good adhesion when the laminated structure is rolled). That is, it is important to obtain a laminated structure with both of these opposite properties being good.

[0010] In particular, due to radiant heat from the lamination device, the ambient temperature around the laminated structure can sometimes rise to around 40°C. Under these conditions, it is also important to obtain a laminated structure with good peelability and adhesion between the resin layer and the second film.

[0011] In view of the above-mentioned problems, the object of the present invention is to provide: a laminated structure in which both the peelability and adhesion of the resin layer and the second film are good under conditions where the ambient temperature around the laminated structure rises to a certain temperature (especially around 40°C), a cured resin layer in the laminated structure, an electronic component having the cured product, and a method for forming the cured product.

[0012] Solution for solving the problem

[0013] The inventors conducted in-depth research and found that in a laminated structure containing a first film, a resin layer containing specific components, and a second film, the peel strength between the second film and the resin layer at an ambient temperature of 40°C is within a specific range, thereby achieving the above-mentioned objective and completing the present invention.

[0014] That is, the aforementioned objective can be achieved through the stacked structure of the present invention.

[0015] The laminated structure is characterized in that it sequentially comprises a first film, a resin layer, and a second film.

[0016] The aforementioned resin layer comprises: (A) an alkali-soluble resin, (B) a multifunctional photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting resin.

[0017] The peel strength between the aforementioned second film and the aforementioned resin layer at an ambient temperature of 40°C is 0.4 to 1.5 N / cm.

[0018] According to a preferred embodiment of the laminated structure of the present invention, the thickness of the aforementioned resin layer is 5 to 100 μm.

[0019] According to another preferred embodiment of the laminated structure of the present invention, the arithmetic mean surface roughness Ra of the surface of the aforementioned resin layer side in the aforementioned second film is less than 0.1 μm.

[0020] According to another preferred embodiment of the laminated structure of the present invention, the melt viscosity of the aforementioned alkali-soluble resin at 90°C is in the range of 100 to 1000 Pa·s.

[0021] According to another preferred embodiment of the laminated structure of the present invention, the alkali-soluble resin (A) having the aforementioned melt viscosity comprises: an alkali-soluble polyurethane resin having the aforementioned melt viscosity, an acid-modified epoxy acrylate resin having the aforementioned melt viscosity, or a combination thereof.

[0022] According to another preferred embodiment of the laminated structure of the present invention, the solid content of the alkali-soluble polyurethane resin having the aforementioned melt viscosity, the solid content of the acid-modified epoxy acrylate resin having the aforementioned melt viscosity, or the solid content of a combination thereof, is 5 to 50% by mass relative to 100% by mass of the solid content of the aforementioned resin layer.

[0023] In addition, the present invention is a cured product, characterized in that it is obtained by curing the aforementioned resin layer in the aforementioned laminated structure.

[0024] In addition, the present invention relates to an electronic component characterized by having the aforementioned cured material.

[0025] In addition, the present invention also relates to a method for forming a cured product, characterized by comprising the following steps:

[0026] The process of peeling off the second film in the aforementioned laminated structure, attaching the resin layer to the substrate on which the circuit is formed, and depositing the first film and the resin layer on the aforementioned substrate.

[0027] In the exposure process, a specified portion of the aforementioned resin layer is irradiated with active energy rays through the aforementioned first thin film;

[0028] In the developing process, the first film is peeled off, and the areas in the resin layer that were not irradiated with active energy rays after the exposure process are removed; and

[0029] In the cured material formation process, the aforementioned resin layer after the aforementioned development process is heated.

[0030] The effects of the invention

[0031] According to the present invention, a laminated structure in which both the peelability and adhesion of the resin layer and the second film are good, particularly when the ambient temperature around the laminated structure rises to a certain temperature (especially around 40°C), a cured resin layer in the laminated structure, an electronic component having the cured product, and a method for forming the cured product are provided. Detailed Implementation

[0032] The laminated structure of the present invention sequentially comprises a first film, a resin layer, and a second film. The resin layer comprises: (A) an alkali-soluble resin, (B) a multifunctional photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting resin. The peel strength between the second film and the resin layer at an ambient temperature of 40°C is 0.4–1.5 N / cm. According to this configuration, a laminated structure exhibits good peel strength and adhesion between the resin layer and the second film, particularly under conditions where the ambient temperature around the laminated structure rises to a certain temperature (especially around 40°C). Furthermore, the peel strength of 0.4–1.5 N / cm prevents misalignment and wrinkles in the rolled laminated structure.

[0033] Between the first film and the resin layer, one or more other resin layers may be included. These additional resin layers may be the same as or different from the resin layer primarily configured between the first film and the second film. That is, the resin composition used to form the other resin layers may be the same as or different from the resin composition used to form the resin layer primarily configured between the first film and the second film.

[0034] [1st film]

[0035] The first film refers to a film that supports the resin layer when a resin layer in a laminated structure is laminated onto a substrate on which a circuit is formed. It is obtained by coating a resin composition used to form the resin layer during its formation. Examples of the first film include polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyimide films, polyamide-imide films, polyethylene films, polytetrafluoroethylene films, polypropylene films, and polystyrene films, all formed from thermoplastic resins. Among these, polyester films are suitable from the viewpoints of heat resistance, mechanical strength, and operability. The thickness of the first film is not particularly limited and can be preferably selected in the range of 10 to 150 μm, more preferably in the range of 15 to 100 μm, and even more preferably in the range of 20 to 75 μm, depending on the application. A demolding process can be performed on the surface of the first film where the resin layer is located. Furthermore, a sputtered layer or an extremely thin copper foil can be formed on the surface of the first film where the resin layer is located. As a commercially available product, one example is "E5041" (polyethylene terephthalate film; 25μm thick) manufactured by Toyobo Co., Ltd.

[0036] [Peel strength between the first film and the resin layer]

[0037] The peel strength between the first film and the resin layer at an ambient temperature of 40°C is preferably higher than that between the second film and the resin layer at an ambient temperature of 40°C, and more preferably 0.5 to 2.5 N / cm.

[0038] The peel strength between the first film and the resin layer can be determined as follows: A 90° peel test according to JIS K6854-1:1999 is performed at an ambient temperature of 40°C. The test apparatus used in the aforementioned 90° peel test can be the Autograph AG-X manufactured by Shimadzu Corporation. This peel strength can be measured at an average peel strength of 50 mm / min and a stroke of 35 mm.

[0039] Specifically, the laminated structure of the present invention is cut into pieces 15 mm wide and 95 mm long. Then, the second film is peeled off, and the exposed resin layer is adhered to a glass epoxy board 15 mm wide, 95 mm long, and 1.6 mm thick using a vacuum laminator (Nikko-Materials Co., Ltd. CVP-300 laminator). Here, the lamination temperature is 70°C, the vacuum holding time is 20 seconds, and the pressurization time is 90 seconds.

[0040] Next, a 15mm wide incision was made along the length of the first film, with sections of 10mm and 5mm width. Then, a portion of the first film was peeled off, clamped, and placed in a 40°C constant temperature bath for 5 minutes. The load at which 30mm was peeled off from one end along a 90-degree angle relative to the glass epoxy board at a speed of 50mm / min was measured, and the peel strength between the first film and the resin layer at an ambient temperature of 40°C was determined. A TCR2W-200T constant temperature bath was used.

[0041] [Resin Layer]

[0042] The resin layer comprises: (A) an alkali-soluble resin, (B) a multifunctional photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting resin. The thickness of this resin layer is preferably 5–100 μm, more preferably 10–90 μm, and even more preferably 25–85 μm. By setting it within this range, the requirements for thinner printed circuit boards can be met. Furthermore, printed circuit boards sometimes have various circuit thicknesses depending on the application, but the laminated structure of the present invention can also be fully applied to printed circuit boards with large circuit thicknesses. The resin layer in the laminated structure of the present invention is formed as follows: a resin composition comprising (A) an alkali-soluble resin, (B) a multifunctional photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting resin is coated onto a first film and dried at 50–150°C for 1–30 minutes. The composition of the resin composition used to form the resin layer will be described below.

[0043] [(A) Alkali-soluble resin]

[0044] Alkali-soluble resins have alkali-soluble groups that are soluble in alkaline aqueous solutions. Alkali-soluble groups include, for example, any one of phenolic hydroxyl groups, thiol groups, and carboxyl groups. Examples of alkali-soluble resins include compounds having two or more phenolic hydroxyl groups, carboxyl-containing resins, compounds having both phenolic hydroxyl and carboxyl groups, and compounds having two or more thiol groups.

[0045] If the alkali-soluble resin is a carboxyl-containing resin or a phenolic resin, its adhesion to the substrate is improved. In particular, if the alkali-soluble resin is a carboxyl-containing resin, its developability is excellent. The carboxyl-containing resin is preferably a carboxyl-containing photosensitive resin with olefinic unsaturated groups, but it can also be a carboxyl-containing resin without olefinic unsaturated groups.

[0046] Specific examples of carboxyl-containing resins include the following compounds (both oligomers and polymers).

[0047] (1) A carboxyl-containing resin obtained by copolymerization of unsaturated carboxylic acids such as (meth)acrylic acid with styrene, α-methylstyrene, lower alkyl esters of (meth)acrylic acid, isobutylene and other compounds containing unsaturated groups.

[0048] (2) A carboxyl-containing polyurethane resin obtained by addition polymerization of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates, and carboxyl-containing diol compounds such as dimethylolpropionic acid and dimethylolbutyric acid, as well as diol compounds such as polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A epoxy alkyl adduct diols, and compounds with phenolic hydroxyl and alcoholic hydroxyl groups.

[0049] (3) A polyurethane resin is obtained by addition polymerization of diisocyanate compounds such as aliphatic diisocyanate, branched aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate, and diol compounds such as polycarbonate polyol, polyether polyol, polyester polyol, polyolefin polyol, acrylic polyol, bisphenol A epoxy alkyl adduct diol, and compounds with phenolic hydroxyl and alcoholic hydroxyl groups, and the end of the polyurethane resin is reacted with an acid anhydride to form a polyurethane resin containing a terminal carboxyl group.

[0050] (4) A carboxyl-containing polyurethane resin obtained by addition polymerization of diisocyanate, 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., meth)acrylate or its partial anhydride modified product, carboxyl-containing diol compound and diol compound.

[0051] (5) The carboxyl-containing polyurethane resin that has been terminally (meth)acrylated by adding compounds such as (meth)acrylic acid hydroxyalkyl esters with one hydroxyl group and one or more (meth)acryloyl groups to the synthesis of the resin in (2) or (4) above.

[0052] (6) The carboxyl-containing polyurethane resin that has been terminally (meth)acrylated by adding equimolar reactants of isophorone diisocyanate and pentaerythritol triacrylate to the synthesis of the resin in (2) or (4) above, and a compound having one isocyanate group and one or more (meth)acryloyl groups in its molecule.

[0053] (7) A carboxyl-containing resin (acid-modified epoxy acrylate resin) is formed by reacting a multifunctional epoxy resin with (meth)acrylic acid to add phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride and other dibasic acid anhydrides to the hydroxyl groups present in the side chain.

[0054] (8) A multifunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of a difunctional epoxy resin with epichlorohydrin is reacted with (meth)acrylic acid to form a carboxyl-containing resin (acid-modified epoxy acrylate resin) by adding a dibasic acid anhydride to the generated hydroxyl groups.

[0055] (9) A carboxyl-containing polyester resin is formed by reacting a polyfunctional oxocyclic butane resin with a dicarboxylic acid and adding a dicarboxylic acid anhydride to the generated primary hydroxyl group.

[0056] (10) A compound having multiple phenolic hydroxyl groups in one molecule is reacted with ethylene oxide, propylene oxide and other epoxides to obtain a reaction product, the reaction product is reacted with a monocarboxylic acid containing an unsaturated group, and the reaction product obtained therefrom is reacted with a polyacid anhydride to obtain a carboxyl-containing resin.

[0057] (11) A compound having multiple phenolic hydroxyl groups in one molecule is reacted with cyclic carbonate compounds such as ethylene carbonate and propylene carbonate to obtain a reaction product. The reaction product is then reacted with a monocarboxylic acid containing an unsaturated group, and the resulting reaction product is then reacted with a polyacid anhydride to obtain a carboxyl-containing resin.

[0058] (12) An epoxy compound having multiple epoxy groups in one molecule is reacted with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenylethanol, and a monocarboxylic acid containing unsaturated groups, such as (meth)acrylic acid, so that the alcoholic hydroxyl group of the reaction product reacts with maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, adipic anhydride, etc., to obtain a carboxyl-containing resin.

[0059] (13) A carboxyl-containing resin formed by further adding compounds having one epoxy group and one or more (meth)acryloyl groups to the carboxyl-containing resins described in (1) to (12) above.

[0060] Examples of compounds having phenolic hydroxyl groups include: compounds having a biphenyl skeleton or a phenylene skeleton or both; phenolic resins having various skeletons synthesized using phenol, o-cresol, p-cresol, m-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, catechol, resorcinol, hydroquinone, methylhydroquinone, 2,6-dimethylhydroquinone, trimethylhydroquinone, pyrogallol, resorcinol, etc.

[0061] In addition, common phenolic resins that are known to be compounds with phenolic hydroxyl groups include phenolic varnish resins, alkylphenolic varnish resins, bisphenol A phenolic varnish resins, dicyclopentadiene-type phenolic resins, Xylok-type phenolic resins, terpene-modified phenolic resins, polyvinylphenols, bisphenol F, bisphenol S-type phenolic resins, poly-p-hydroxystyrene, condensates of naphthol and aldehydes, and condensates of dihydroxynaphthalene and aldehydes.

[0062] As an alkali-soluble resin, one of the above compounds can be used alone or in combination of two or more.

[0063] The melt viscosity of the alkali-soluble resin at 90°C is preferably in the range of 100–1000 Pa·s, more preferably in the range of 120–700 Pa·s, and even more preferably in the range of 150–500 Pa·s. By setting this range, it becomes easier to adjust the peel strength between the second film and the resin layer at an ambient temperature of 40°C to a range of 0.4–1.5 N / cm. Furthermore, when the resin layer is laminated onto a substrate with circuitry formed at 90°C, air entrainment (bubble entrapment) in the shoulder portion of the circuitry can be suppressed. The melt viscosity is measured according to the following melt viscosity measurement method. It should be noted that if the measuring equipment used is difficult to obtain due to defective printing plates, etc., other equipment with equivalent performance can be used; the same applies to other measuring equipment described in this specification. The above-mentioned range of melt viscosity of the alkali-soluble resin can be controlled, for example, based on the melt viscosity of the main component constituting the alkali-soluble resin and / or the mixing amount of the main component.

[0064] (Methods for determining melt viscosity)

[0065] An alkali-soluble resin was diluted with propylene glycol monomethyl ether acetate to form a resin solution, which was then encapsulated onto a fluoropolymer (AGC Arflex 50HK NT). The solution was heated in an oven at 100°C for 10 hours to form a dried resin plate approximately 1 mm thick and 25 mm in diameter. The melt viscosity was then measured using a Thermo Scientific RS-6000 under the following conditions.

[0066] (Conditions for determining melt viscosity)

[0067] Sensor: Φ20mm parallel plate type

[0068] Heating rate: 5℃ / minute

[0069] Measurement frequency: 1Hz

[0070] Measured pressure: 3 Pa

[0071] As the main component of the alkali-soluble resin having the aforementioned melt viscosity, an alkali-soluble resin having (meth)acryloyl groups with the aforementioned melt viscosity is preferred. Specifically, it is preferred to include an alkali-soluble polyurethane resin (more specifically, the polyurethane resins of (2) to (6) above), an acid-modified epoxy acrylate resin having the aforementioned melt viscosity (more specifically, the alkali-soluble resins of (7) and (8) above), or a combination thereof. The range of melt viscosity of the main component constituting the alkali-soluble resin (e.g., alkali-soluble polyurethane resin, acid-modified epoxy acrylate resin) can be controlled based on the technical knowledge of those skilled in the art.

[0072] The solid content of the alkali-soluble polyurethane resin having the aforementioned melt viscosity, the solid content of the acid-modified epoxy acrylate resin having the aforementioned melt viscosity, or a combination thereof, is preferably 5 to 50% by mass relative to 100% by mass of the solid content of the aforementioned resin layer. It should be noted that, in the case of a combination of the alkali-soluble polyurethane resin having the aforementioned melt viscosity and the acid-modified epoxy acrylate resin having the aforementioned melt viscosity, the ratio of the solid content of the alkali-soluble polyurethane resin having the aforementioned melt viscosity to the solid content of the acid-modified epoxy acrylate resin having the aforementioned melt viscosity is preferably 15 to 85:85 to 15, more preferably 40 to 60:60 to 40, and most preferably 50:50. By setting it within this range, both the peelability and adhesion between the resin layer and the second film are good.

[0073] An acid value of 40–200 mg KOH / g is suitable for alkali-soluble resins, and more preferably 45–120 mg KOH / g. If the acid value of the alkali-soluble resin is above 40 mg KOH / g, alkali development becomes easier.

[0074] On the other hand, when the concentration is below 200 mg KOH / g, it becomes easier to depict normal cured product patterns, which is therefore preferred.

[0075] The weight-average molecular weight of alkali-soluble resins varies depending on the resin skeleton, preferably in the range of 1500 to 150,000, and more preferably in the range of 1500 to 100,000. When the weight-average molecular weight is above 1500, the non-stick properties are good, the moisture resistance of the coating after exposure is good, film loss during development is suppressed, and the reduction in resolution can be suppressed.

[0076] On the other hand, when the weight-average molecular weight is below 150,000, it exhibits good developability and excellent storage stability.

[0077] (B) Multifunctional photopolymerizable monomers

[0078] As a multifunctional photopolymerizable monomer, it is a compound having two or more olefinic unsaturated groups in its molecule. It can be photopolymerizable oligomers, photopolymerizable vinyl monomers, etc., which are known and commonly used photocurable monomers.

[0079] Examples of photopolymerizable oligomers include unsaturated polyester oligomers and (meth)acrylate oligomers. Examples of (meth)acrylate oligomers include phenolic varnish epoxy (meth)acrylate, cresol phenolic varnish epoxy (meth)acrylate, bisphenol-type epoxy (meth)acrylate, urethane (meth)acrylate, epoxy urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, and polybutadiene-modified (meth)acrylate. It should be noted that in this specification, (meth)acrylate is a general term encompassing acrylates, methacrylates, and mixtures thereof, and the same applies to other similar expressions.

[0080] Examples of photopolymerizable vinyl monomers include commonly known and frequently used compounds such as triallyl isocyanurate, diallyl phthalate, and diallyl isophthalate, which are polyfunctional allyl compounds; ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate, etc. Alkylene polyol poly(meth)acrylates; diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane tri(meth)acrylate, and other polyoxyalkylene glycol poly(meth)acrylates; neopentyl glycol hydroxypentanoate di(meth)acrylate and other poly(meth)acrylates; tri[(meth)acryloyloxyethyl]isocyanurate and other isocyanurate-type poly(meth)acrylates, etc. These can be used alone or in combination of two or more, depending on the required properties. For example, commercially available products include "Aronix M-350" (trimethylolpropane EO-modified triacrylate) manufactured by Toa Synthetic Co., Ltd.

[0081] The solid content of the multifunctional photopolymerizable monomer is preferably 10 to 40% by mass relative to 100% by mass of the solid content of the aforementioned resin layer.

[0082] [(C) Photopolymerization initiator]

[0083] As a photopolymerization initiator, any photopolymerization initiator known as a photopolymerization initiator or a photoradical generator can be used.

[0084] Examples of photopolymerization initiators 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, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, etc., all of which are diacylphosphine oxides; 2,6-dimethoxy... Benzoyl diphenylphosphine oxide, 2,6-dichlorobenzoyl diphenylphosphine oxide, methyl 2,4,6-trimethylbenzoylphenylphosphine acid ester, 2-methylbenzoyl diphenylphosphine oxide, isopropyl neopentanoyl phenylphosphine acid ester, 2,4,6-trimethylbenzoyl diphenylphosphine oxide and other monoacylphosphine oxides; hydroxyacetophenones such as 1-hydroxy-cyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanoyl)-benzyl]phenyl}-2-methyl-propane-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1-one and other hydroxyacetophenones; benzoin, benzoyl... Benzoin derivatives include benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and benzoin n-butyl ether; benzoin alkyl ethers; benzophenones such as p-methylbenzophenone, mifepristone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bis(diethylamino)benzophenone; acetophenones, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, and 2-(dimethylamino)-2-[ (4-Methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone, N,N-dimethylaminoacetophenone and other acetophenone derivatives; thioxanone derivatives such as 2-ethylthioxanone, 2-isopropylthioxanone, 2,4-dimethylthioxanone, 2,4-diethylthioxanone, 2-chlorothioxanone, 2,4-diisopropylthioxanone and other thioxanone derivatives; anthraquinone derivatives such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-pentylanthraquinone, 2-aminoanthraquinone and other anthraquinone derivatives; acetophenone dimethyl ketal, benzoyl dimethyl ketal and other ketals; benzoate derivatives such as ethyl 4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, ethyl p-dimethylbenzoate and other benzoate derivatives;Oxime esters such as 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-acetone 1-(O-acetyl oxime); titanium oxides such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrolo-1-yl)phenyl)titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyrrolo-1-yl)ethyl)phenyl]titanium; 2-nitrofluorene disulfide, butylin, anisolein ethyl ether, azobisisobutyronitrile, tetramethylthiuram disulfide, etc. Photopolymerization initiators can be used alone or in combination of two or more. Among them, monoacylphosphine oxides, preferably oxime esters, and more preferably 2,4,6-trimethylbenzoyl diphenylphosphine oxide and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-acetone 1-(O-acetyl oxime).

[0085] The content of the photopolymerization initiator is preferably 0.1 to 40% by mass, more preferably 0.3 to 20% by mass, relative to 100% by mass of the solid content of the aforementioned resin layer.

[0086] [(D) Thermosetting resin]

[0087] The aforementioned resin layer preferably comprises a thermosetting resin. As a thermosetting resin, any resin that exhibits electrical insulation properties upon curing by heating is suitable; examples include epoxy compounds, oxetane compounds, melamine resins, and silicone resins. In particular, in this invention, epoxy compounds and oxetane compounds can be used, and they can be used in combination.

[0088] As the aforementioned epoxy compounds, commonly known compounds having one or more epoxy groups can be used, among which compounds having two or more epoxy groups are preferred. Examples include: monoepoxy compounds such as butyl glycidyl ether, phenyl glycidyl ether, and glycidyl (meth)acrylate; bisphenol A type epoxy resin, bisphenol S type epoxy resin, bisphenol F type epoxy resin, phenolic varnish type epoxy resin, cresol phenolic varnish type epoxy resin, alicyclic epoxy resin, trimethylolpropane polyglycidyl ether, phenyl-1,3-diglycidyl ether, biphenyl-4,4'-diglycidyl ether, 1,6-hexanediol diglycidyl ether, ethylene glycol or propylene glycol diglycidyl ether, sorbitol polyglycidyl ether, tris(2,3-epoxypropyl) isocyanurate, and triglycidyl tri(2-hydroxyethyl) isocyanurate, etc., which have two or more epoxy groups per molecule. They can be used individually or in combination of two or more, depending on the required characteristics.

[0089] In addition, examples of epoxy resins include: Mitsubishi Chemical Corporation's jER828, jER834, jER1001, and jER1004; DIC Corporation's EPICLON 840, 850, 850-S, 1050, and 2055; NIPPON STEEL Chemical & Material Co., Ltd.'s EPOTOHTO YD-011, YD-013, YD-127, and YD-128; Dow Chemical's DER317, DER331, DER661, and DER664; and Sumitomo Chemical Corporation's SUMI-EPOXY. Bisphenol A type epoxy resins such as ESA-011, ESA-014, ELA-115, and ELA-128 (all trade names); brominated epoxy resins such as jERYL903 (Mitsubishi Chemical Corporation), EPICLON 152 and 165 (DIC Corporation), EPOTOHTO YDB-400 and YDB-500 (NIPPON STEEL Chemical & Material Co., Ltd.), DER542 (Dow Chemical), and SUMI-EPOXY ESB-400 and ESB-700 (Sumitomo Chemical Corporation); and brominated epoxy resins such as jER152 and jER154 (Mitsubishi Chemical Corporation), DEN431 and DEN438 (Dow Chemical), EPICLON N-730, N-770, and N-865 (DIC Corporation). EPOTOHTO YDCN-701 and YDCN-704 manufactured by Chemical & Material Co., Ltd.; EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306, NC-3000, and NC-3000L manufactured by Nippon Kayaku Co., Ltd.; SUMI-EPOXY ESCN-195X and ESCN-220 manufactured by Sumitomo Chemical Co., Ltd.; YDCN-700-2, YDCN-700-3, YDCN-700-5, YDCN-700-7, YDCN-700-10, YDCN-704, and YDCN-704A manufactured by NIPPON STEEL Chemical & Material Co., Ltd.; and EPICLON manufactured by DIC Co., Ltd. Phenolic varnish-type epoxy resins such as N-680, N-690, and N-695 (all trade names); EPICLON 830 manufactured by DIC Corporation; jER807 manufactured by Mitsubishi Chemical Corporation; and NIPPON STEEL Chemical & Material Co.Bisphenol F type epoxy resins such as EPOTOHTO YDF-170, YDF-175, and YDF-2004 (all trade names) manufactured by NIPPONSTEEL Chemical & Material Co., Ltd.; hydrogenated bisphenol A type epoxy resins such as EPOTOHTO ST-2004, ST-2007, and ST-3000 (trade names) manufactured by NIPPONSTEEL Chemical & Material Co., Ltd., and YX8034 manufactured by Mitsubishi Chemical Corporation; glycidylamine type epoxy resins such as jER604 manufactured by Mitsubishi Chemical Corporation, EPOTOHTO YH-434 manufactured by NIPPON STEEL Chemical & Material Co., Ltd., and SUMI-EPOXY ELM-120 manufactured by Sumitomo Chemical Co., Ltd.; hydantoin type epoxy resins; and CELLOXIDE manufactured by Daicel Corporation. Alicyclic epoxy resins such as 2021, etc. (all trade names); trihydroxyphenylmethane type epoxy resins such as YL-933 manufactured by Mitsubishi Chemical Corporation, and EPPN-501 and EPPN-502 manufactured by Nippon Kayaku Co., Ltd. (all trade names); bixylenol type or biphenol type epoxy resins or mixtures thereof manufactured by Mitsubishi Chemical Corporation, such as YL-6056, YX-4000, and YL-6121 (all trade names); EBPS-200, A, etc. manufactured by Nippon Kayaku Co., Ltd. EPX-30 manufactured by DEKA Corporation, EXA-1514 (trade name) manufactured by DIC Corporation, and other bisphenol S type epoxy resins; jER157S (trade name) manufactured by Mitsubishi Chemical Corporation, and other bisphenol A phenolic varnish type epoxy resins; jERYL-931 (all trade names) manufactured by Mitsubishi Chemical Corporation, and other tetrahydroxyphenyl ethane type epoxy resins; TEPIC (all trade names) manufactured by Nissan Chemical Corporation, and other heterocyclic epoxy resins; BLEMMER DGT (phthalic acid diglycidyl ester) resins manufactured by Nippon Oil Co., Ltd.; ZX-1063 (tetraglycidyl dimethylbenzeneyl ethane) resin manufactured by NIPPON STEEL Chemical & Material Co., Ltd.; NIPPON STEEL Chemical & Material Co., Ltd.Epoxy resins containing a naphthalene backbone, such as ESN-190, ESN-360, HP-4032, EXA-4750, and EXA-4700 manufactured by DIC Corporation; epoxy resins with a dicyclopentadiene backbone, such as HP-7200 and HP-7200H manufactured by DIC Corporation; glycidyl methacrylate copolymer epoxy resins such as CP-50S and CP-50M manufactured by Nippon Oil Co., Ltd.; and copolymer epoxy resins of cyclohexylmaleimide and glycidyl methacrylate; CTBN-modified epoxy resins (such as YR-102 and YR-450 manufactured by NIPPON STEEL Chemical & Material Co., Ltd.), etc., but not limited to these.

[0090] These epoxy resins can be used alone or in combination of two or more.

[0091] Next, oxetane compounds will be described. Specific examples of oxetane compounds containing an oxetane ring as shown in the following general formula (I) will be provided.

[0092]

[0093] (where R is in the formula) 1 Examples of oxetane compounds (representing hydrogen atoms or alkyl groups having 1 to 6 carbon atoms) include 3-ethyl-3-hydroxymethyloxetane (TOA Synthetic Co., Ltd. OXT-101), 3-ethyl-3-(phenoxymethyl)oxetane (TOA Synthetic Co., Ltd. OXT-211), 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane (TOA Synthetic Co., Ltd. OXT-212), 1,4-bis{[(3-ethyl-3-oxetane)methoxy]methyl}benzene (TOA Synthetic Co., Ltd. OXT-121), and bis(3-ethyl-3-oxetane)methyl ether (TOA Synthetic Co., Ltd. OXT-221). Furthermore, examples include phenolic varnish-type oxetane compounds. These oxetane compounds can be used in combination with the aforementioned epoxide compounds, or they can be used alone.

[0094] The solid content of the thermosetting resin is preferably in the following ratio: the equivalent ratio of the functional groups (alkali-soluble groups such as carboxyl groups) of the alkali-soluble resin to the functional groups (thermosetting groups such as epoxy groups) of the thermosetting resin that can react with the functional groups is preferably 1:0.1 to 1:10, more preferably 1:0.2 to 1:5, and even more preferably 1:0.5 to 1:2.5. With this equivalent ratio, finely patterned cured products with good developability can be formed.

[0095] [Second film]

[0096] The second film is disposed on the side of the resin layer opposite to the first film for the purpose of preventing dust and other contaminants from adhering to the surface of the resin layer of the laminated structure and improving operability. As the second film, for example, a film formed from a thermoplastic resin as exemplified in the first film described above can be used. Among these, polyester film, polyethylene film, polypropylene film, and films whose surfaces have undergone a release treatment are preferred. The thickness of the second film is not particularly limited and can be suitably selected according to the application, preferably in the range of 10 to 150 μm, more preferably in the range of 12.5 to 100 μm, and even more preferably in the range of 15 to 50 μm. A release treatment can be performed on the side of the second film where the resin layer is disposed.

[0097] The second film preferably has an arithmetic mean surface roughness Ra of less than 0.1 μm. By setting it to this range (by smoothing the surface of the second film), a state can be formed in which the second film moderately adheres to the resin layer with high adhesiveness. That is, the resin layer and the second film can be peeled off well.

[0098] The following describes the specific method for measuring the arithmetic mean surface roughness Ra. The arithmetic mean surface roughness Ra can be measured using a shape measurement laser microscope (e.g., KEYENCE CORPORATION VK-X100). After starting the shape measurement laser microscope (same VK-X100) main body (control unit) and the VK observation application (KEYENCE CORPORATION VK-H1VX), place the sample (second thin film) to be measured on the xy stage. Rotate the lens rotation lever of the microscope unit (KEYENCE CORPORATION VK-X110), select a 10x objective lens, and roughly adjust the focus and brightness in the image observation mode of the VK observation application (same VK-H1VX). Operate the xy stage, adjusting it so that the part of the sample surface to be measured is centered in the image. Replace the 10x objective lens with a 50x objective lens, and use the autofocus function in the image observation mode of the VK observation application (same VK-H1VX) to focus on the surface of the sample. Select the simple mode for shape measurement of the pellet in the VK observation application (same as VK-H1VX), press the measurement start button to measure the surface shape of the sample, and obtain a surface image file. Start the VK analysis application (KEYENCE CORPORATION VK-H1XA), and after the obtained surface image file is displayed, perform slope correction. It should be noted that the transverse observation measurement range in the sample surface shape measurement is set to 270μm. Display the line roughness window, select JISB0601-1994 in the parameter setting area, select the horizontal line from the measurement line button, display the horizontal line at any position in the surface image, and press the OK button to obtain the arithmetic mean surface roughness Ra value. Then, display the horizontal line at four different locations in the surface image to obtain the arithmetic mean surface roughness Ra values ​​for each location. Calculate the average of the five obtained values ​​as the arithmetic mean surface roughness Ra of the sample surface.

[0099] As a second thin film having the aforementioned arithmetic mean surface roughness Ra, when using a thermoplastic resin film, a thermoplastic resin film having the aforementioned arithmetic mean surface roughness Ra can be obtained by adding fillers to the resin during film formation, sandblasting the film surface, or forming a specified morphology through hairline processing, matte coating, or chemical etching. For example, when adding fillers to the resin, the arithmetic mean surface roughness Ra can be controlled by adjusting the filler particle size and amount. Furthermore, when performing sandblasting, the arithmetic mean surface roughness Ra can be controlled by adjusting the sandblasting material, sandblasting pressure, and other processing conditions. Commercially available products include, for example, "E-201F" (biaxially stretched polypropylene film) manufactured by Oji F-Tex Co., Ltd., "TN100" and "TN200" (molding-treated polyethylene terephthalate film) manufactured by Toyobo Co., Ltd., or "CeraPure PJ271" and "CeraPure PJ111" (molding-treated polyethylene terephthalate film) manufactured by Toray Industries, Ltd.

[0100] [Peel strength between the second film and the resin layer]

[0101] The peel strength between the second film and the resin layer at an ambient temperature of 40°C is 0.4–1.5 N / cm. This range of peel strength, combined with a resin layer having specific components, allows for good peel strength and adhesion between the resin layer and the second film, especially when the ambient temperature around the laminated structure rises to a certain temperature (particularly around 40°C). The peel strength between the second film and the resin layer is measured in a 90° peel test according to JIS K6854-1:1999 at an ambient temperature of 40°C. The test apparatus used in the aforementioned 90° peel test can be the Autograph AG-X manufactured by Shimadzu Corporation. The peel strength can be measured at an average peel strength of 50 mm / min and a travel distance of 35 mm.

[0102] Specifically, after cutting the laminated structure of the present invention into pieces 15 mm wide and 95 mm long, a 15 mm wide double-sided adhesive tape (Nicetack NW-K15, manufactured by NICHIBAN Co., Ltd.) is adhered along the length direction to the surface of the first film with a margin. Then, the margin of the double-sided adhesive tape is cut in the same manner as the size of the laminated structure (15 mm wide and 95 mm long) to bond the double-sided adhesive tape to the surface of the first film for a glass epoxy board with a width of 15 mm, a length of 95 mm, and a thickness of 1.6 mm. Cuts are made along the length direction of the second film, with a width of 15 mm, spaced 10 mm wide and 5 mm wide. Then, a portion of the second film was peeled off, clamped, and placed in a constant temperature bath at 40°C for 5 minutes. The load was then measured when peeling 30mm from one end of the glass epoxy board along a 90-degree angle at a speed of 50mm / min and a stroke of 35mm. The peel strength between the second film and the resin layer at an ambient temperature of 40°C was determined. A TCR2W-200T constant temperature bath was used.

[0103] The aforementioned range (0.4–1.5 N / cm) of the peel strength between the second film and the resin layer can be controlled primarily by changing the melt viscosity of the alkali-soluble resin at 90°C or adjusting its mixing amount, thereby additionally taking into account, for example, the thickness of the second film, the arithmetic mean surface roughness Ra of the second film, and / or the compatibility between the alkali-soluble resin and the second film.

[0104] On the other hand, the peel strength between the first film and the resin layer at an ambient temperature of 40°C is preferably 1.6 to 2.5 N / cm. If this range is met, the effect of preventing damage to the resin layer during the peeling of the second film can be achieved. It should be noted that the peel strength between the first film and the resin layer at an ambient temperature of 40°C can be measured using the same method as described above.

[0105] [Inorganic packing]

[0106] The aforementioned resin layer may also contain inorganic fillers. Preferably, it contains surface-treated inorganic fillers. Here, surface treatment of the inorganic filler refers to a treatment used to improve compatibility with the resin components. Preferably, the surface treatment of the inorganic filler involves introducing curable reactive groups onto its surface.

[0107] There are no particular limitations on the inorganic filler used; commonly known fillers such as silica, crystalline silica, Noiburg silica, aluminum hydroxide, glass powder, talc, clay, magnesium carbonate, calcium carbonate, natural mica, synthetic mica, aluminum hydroxide, barium sulfate, barium titanate, iron oxide, non-fibrous glass, hydrotalcite, mineral wool, aluminum silicate, calcium silicate, and zinc oxide are acceptable. Silica is preferred, and spherical silica is more preferred due to its small surface area and the fact that stress is dispersed throughout the structure, making it less likely to become the initiation point of cracks. Commercially available products include, for example, aluminum hydroxide manufactured by Showa Denko Co., Ltd.

[0108] The content of inorganic filler is preferably 1 to 300% by mass, more preferably 5 to 150% by mass, relative to 100% by mass of the solid content of the aforementioned resin layer.

[0109] [Any other ingredients]

[0110] Other curing components and additives commonly known in the field of compounding electronic materials into the aforementioned resin layer include cyanate ester resins, reactive ester resins, maleimide compounds, and alicyclic olefin polymers. Other additives include non-silicone release agents, photoalkalizing agents, thermosetting catalysts, colorants, organic solvents, thermal polymerization inhibitors, ultraviolet absorbers, silane coupling agents, plasticizers, flame retardants, antistatic agents, antioxidants, antibacterial and antifungal agents, defoamers, leveling agents, thickeners, adhesion promoters, thixotropic agents, photoinitiating agents, sensitizers, thermoplastic resins, organic fillers, mold release agents, surface treatment agents, dispersants, dispersing aids, surface modifiers, stabilizers, and phosphors.

[0111] [Methods for forming layered structures]

[0112] When forming a laminated structure, firstly, a resin composition comprising (A) an alkali-soluble resin, (B) a multifunctional photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting resin is coated onto a first film at a uniform thickness using a comma-type coater or a scraper coater. Then, the coated resin composition is dried at a temperature of 40–130°C for 1–30 minutes to form a resin layer. Next, a second film is bonded to the surface of the resin layer opposite to the first film to form the laminated structure. It should be noted that by coating and drying the resin composition onto the second film to form a resin layer, the first film can then be bonded. Furthermore, if the laminated structure is elongated, it can be rolled into a roll to form a rolled laminated structure. The rolled laminated structure can be cut to a specified width as needed.

[0113] [Method for forming a resin layer on a cured circuit board]

[0114] The method for forming a cured resin layer on a circuit board (specifically, the method for forming a cured resin layer in the above-mentioned laminated structure) can be performed by a method including the following steps:

[0115] The process of peeling off the second film in the aforementioned laminated structure, attaching the resin layer to the substrate on which the circuit is formed, and depositing the first film and the resin layer on the aforementioned substrate.

[0116] In the exposure process, a specified portion of the aforementioned resin layer is irradiated with active energy rays through the aforementioned first thin film;

[0117] In the developing process, the first film is peeled off, and the areas in the resin layer that were not irradiated with active energy rays after the exposure process are removed; and

[0118] In the cured material formation process, the aforementioned resin layer after the aforementioned development process is heated.

[0119] (The process of attaching a resin layer to a substrate on which circuitry is formed)

[0120] As a process for attaching the resin layer to a substrate on which the circuit is formed, a vacuum laminator or similar device is preferably used to peel off the second film from the resin layer and bond it under pressure and heat. By using such a vacuum laminator, the laminated structure is tightly bonded to the surface of the substrate on which the circuit is formed, thus preventing the incorporation of air bubbles and improving the filling of recesses on the surface of the circuit substrate. The pressure conditions are preferably around 0.1 to 2.0 MPa, and the heating conditions are preferably 40 to 120°C.

[0121] (Exposure process)

[0122] In the exposure process, the resin layer containing the photopolymerization initiator is exposed at an exposure dose of, for example, 50 mJ / cm. 2 ~1000mJ / cm 2 Under certain conditions, light irradiation can be applied to cure the resin layer. Light irradiation is performed using active energy rays such as ultraviolet rays, electron beams, and chemical rays. As a method for irradiating a specified area with active energy rays, one approach is to selectively irradiate the active energy rays using a photomask with a specified pattern. Direct tracing devices (e.g., laser direct imaging devices that directly draw images using lasers based on CAD data from a computer) can be used.

[0123] (Developing process)

[0124] In the development process, after the first film is peeled off, alkaline development is used to remove the unexposed areas, forming a negative patterned cured film. The development method can be based on known methods such as immersion. Furthermore, the developing solution can be sodium carbonate, potassium carbonate, potassium hydroxide, amines, imidazoles such as 2-methylimidazole, alkaline aqueous solutions such as tetramethylammonium hydroxide (TMAH), or mixtures thereof.

[0125] (Cure formation process)

[0126] In the curing process, the photocured resin layer can be thermally cured using known heating methods, such as hot air furnaces, electric furnaces, infrared induction heating furnaces, etc. As for heating conditions, heating at 150°C to 170°C for 5 to 120 minutes is preferred.

[0127] Examples of substrates on which circuits are formed include thin films formed of glass polyimide, polyimide, polyethylene terephthalate, liquid crystal polymers, polycarbonate, etc., but are not limited to these; conventionally known circuit substrates may be used.

[0128] [Cure of the resin layer]

[0129] The cured resin layer of the circuit board (i.e., the cured resin layer in the laminated structure that does not have the aforementioned first film and the aforementioned second film) also has excellent flexibility, and therefore is particularly suitable as a cover layer and solder resist layer (insulating curing film) for flexible printed circuit boards.

[0130] [Electronic components characterized by a cured resin layer]

[0131] This invention also provides electronic components having a cured resin layer. In this invention, "electronic component" refers to a component used in electronic circuits, including active components such as printed circuit boards, particularly flexible printed circuit boards, transistors, light-emitting diodes, and laser diodes, as well as passive components such as resistors, capacitors, inductors, and connectors. The cured resin layer of this invention is suitable as an insulating cured film for these components.

[0132] Example

[0133] The present invention will now be described in more detail with reference to the embodiments, but the present invention is not limited to the embodiments described below. It should be noted that, unless otherwise specified, "parts" and "%" all refer to mass.

[0134] (Synthesis of alkali-soluble polyurethane resin A-1)

[0135] In a 2L flask equipped with a stirrer and a reflux duct, 378.0g of bisphenol A type epoxy compound (Mitsubishi Chemical Corporation "828"; difunctional bisphenol A type epoxy resin, epoxy equivalent: 189g / equivalent), 142.7g of acrylic acid (molecular weight: 72.06), 2.94g of 2,6-di-tert-butyl-p-cresol as a heat inhibitor, and 1.53g of triphenylphosphine as a reaction catalyst were added. The reaction was carried out at 98°C until the acid value of the reaction solution became below 0.5mgKOH / g, yielding epoxy acrylate compound (a) (theoretical molecular weight: 510.7).

[0136] Then, 594.0 g of carbitol acetate and 105.5 g of dimethylolpropionic acid (b) (molecular weight: 134.16) were added to the reaction solution as a solvent, and the temperature was raised to 45°C. Then, 264.7 g of isophorone diisocyanate (c) (molecular weight: 222.28) was slowly added dropwise to the solution, ensuring the reaction temperature did not exceed 65°C. After the addition was complete, the temperature was raised to 80°C, and the reaction was carried out for 6 hours until the concentration of 2250 cm⁻¹ was reached, according to infrared absorption spectroscopy. -1 The absorption of the nearby isocyanate groups disappeared, and the reaction was further carried out at 98°C for 2 hours. This yielded a resin solution (alkali-soluble polyurethane resin A-1) containing 60% by mass of alkali-soluble polyurethane resin (A) based on the solids content concentration. The acid value was measured and found to be 28.9 mg KOH / g (solids content acid value: 48.2 mg KOH / g).

[0137] (Synthesis of alkali-soluble polyurethane resin A-2)

[0138] In a reaction vessel equipped with a stirrer, thermometer, and condenser, 3600 g (4.5 mol) of polycarbonate diol (manufactured by Asahi Kasei Chemicals Co., Ltd., "TJ5650J", number average molecular weight 800), a compound having two or more alcoholic hydroxyl groups derived from 1,5-pentanediol and 1,6-hexanediol, was added; 814 g (5.5 mol) of dimethylolbutyric acid; and 186 g (1.6 mol) of 2-hydroxyethyl acrylate as a molecular weight regulator (reaction terminator). Next, 2009 g (10.8 mol) of trimethylhexamethylene diisocyanate, an isocyanate compound without an aromatic ring, was added. The mixture was heated to 60°C while stirring and then stopped. Heating was resumed when the temperature inside the reaction vessel began to decrease, and stirring was continued at 80°C. The absorption spectrum of the isocyanate group in the infrared absorption spectrum (2280 cm⁻¹) was confirmed. -1The reaction ended when the solids disappeared. Next, carbitol acetate was added at a solid content of 60% by mass to obtain a viscous liquid containing a carboxyl-containing alkali-soluble polyurethane resin (alkali-soluble polyurethane resin A-2). The acid value of the solids component of the obtained carboxyl-containing alkali-soluble polyurethane resin A-2 was 49.8 mg KOH / g.

[0139] (Synthesis of acid-modified epoxy acrylate resin A-3)

[0140] 380 parts of bisphenol F type epoxy resin (epoxy equivalent 950 g / eq, softening point 85℃) with an average degree of polymerization n of 6.2 and 925 parts of epichlorohydrin were dissolved in 462.5 parts of dimethyl sulfoxide. Then, 60.9 parts of 98.5% NaOH were added over 100 minutes at 70℃ with stirring. The reaction was further carried out at 70℃ for 3 hours after the addition. After the reaction was completed, 250 parts of water were added for washing. After oil-water separation, most of the dimethyl sulfoxide and excess unreacted epichlorohydrin were recovered from the oil layer by distillation under reduced pressure. The reaction product, containing residual by-product salts and dimethyl sulfoxide, was dissolved in 750 parts of methyl isobutyl ketone. Then, 10 parts of 30% NaOH were added, and the reaction was carried out at 70℃ for 1 hour. After the reaction was completed, the product was washed twice with 200 parts of water. After oil-water separation, methyl isobutyl ketone was recovered by distillation from the oil layer to obtain epoxy resin (a) with an epoxy equivalent of 310 g / eq and a softening point of 69 °C. When the epoxy resin (a) was calculated based on the epoxy equivalent, approximately 5 out of the 6.2 alcoholic hydroxyl groups in the aforementioned starting material, bisphenol F type epoxy resin, were epoxidized. 310 parts of this epoxy resin (a) and 282 parts of carbitol acetate were added to a flask and heated and stirred at 90 °C to dissolve. The resulting solution was temporarily cooled to 60 °C, and 72 parts (1 mol) of acrylic acid, 0.5 parts of methylhydroquinone, and 2 parts of triphenylphosphine were added. The mixture was heated to 100 °C and reacted for approximately 60 hours to obtain a reactant with an acid value of 0.2 mg KOH / g. 140 parts (0.92 mol) of tetrahydrophthalic anhydride were added to this reactant, and the mixture was heated to 90 °C to react, yielding an acid-modified epoxy acrylate resin (acid-modified epoxy acrylate resin A-3). The obtained acid-modified epoxy acrylate resin A-3 has a solid content concentration of 62% by mass and a solid content acid value (mgKOH / g) of 100.

[0141] (Synthesis of acid-modified epoxy acrylate resin A-4)

[0142] In a four-necked flask equipped with a stirrer and a reflux condenser, 220 parts of cresol phenolic varnish-type epoxy resin (DIC Corporation "EPICLON N-695"; epoxy equivalent: 220) and 214 parts of carbitol acetate were added and heated to dissolve. Next, 0.1 parts of hydroquinone as a polymerization inhibitor and 2.0 parts of dimethylbenzylamine as a reaction catalyst were added. The mixture was heated to 95–105°C, and 72 parts of acrylic acid were slowly added dropwise, reacting for 16 hours. The reaction product was cooled to 80–90°C, and 106 parts of tetrahydrophthalic anhydride were added, reacting for 8 hours. After cooling, the product was removed.

[0143] The acid-modified epoxy acrylate resin (acid-modified epoxy acrylate resin A-4) obtained in this way is as follows: solid content 65%, acid value of solids 100 mg KOH / g, and weight-average molecular weight Mw approximately 3500.

[0144] (Determination of the melt viscosity of the alkali-soluble resin obtained in the synthesis example)

[0145] Resin solutions of alkali-soluble polyurethane resin A-1, alkali-soluble polyurethane resin A-2, acid-modified epoxy acrylate resin A-3, and acid-modified epoxy acrylate resin A-4 were encapsulated onto fluoropolymer resin (AGC Arflex 50HK NT) and heated in an oven at 100°C for 10 hours to form a dried resin plate approximately 1 mm thick and 25 mm in diameter. The melt viscosity was measured using a ThermoScientific RS-6000 under the following conditions. The results are shown in Table 1 below.

[0146] (Conditions for determining melt viscosity)

[0147] Sensor: Φ20mm parallel plate type

[0148] Heating rate: 5℃ / minute

[0149] Measurement frequency: 1Hz

[0150] Measured pressure: 3 Pa

[0151] [Table 1]

[0152]

[0153] (Examples 1-18 and Comparative Examples 1-7)

[0154] Create a stacked structure using the method described below.

[0155] (Preparation of resin compositions for forming resin layers)

[0156] Based on the formulations described in Table 2, the components described in the Examples and Comparative Examples were mixed, premixed in a mixer, and then kneaded using a three-roll mill to prepare resin compositions for forming resin layers in laminated structures. Unless otherwise specified, the values ​​in the table are by mass (%), representing the amount of solids.

[0157] (Construction of layered structures)

[0158] A 25 μm thick polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., "E5041") was prepared as the first film. The resin composition obtained above was coated onto this film and dried at 80°C for 15 minutes to form a resin layer with a thickness of 25 μm. Next, E-201F (biaxially stretched polypropylene film manufactured by Oji F-Tex Co., Ltd.) was laminated as the second film to obtain the laminated structures of Examples 1-4 and Comparative Examples 1-2, in which a resin layer is disposed between the first film and the second film.

[0159] [Table 2]

[0160]

[0161] ※1 Trimethylolpropane EO-modified triacrylate (manufactured by Toa Synthetic Co., Ltd.)

[0162] ※2 2,4,6-Trimethylbenzoyldiphenylphosphine oxide

[0163] ※3-Biphenylaryl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.)

[0164] ※4 Aluminum hydroxide (manufactured by Showa Denko Co., Ltd.)

[0165] (Adhesion between the second film and the resin layer)

[0166] When the above-mentioned laminated structure was manufactured using a roller laminator (VA-770, manufactured by Taisei Laminator Co., Ltd.) with the lamination roller temperature set at 50°C and the pressure set at 0.2 MPa, the adhesion of the second film to the resin layer was evaluated. The evaluation results are shown in Table 3 below.

[0167] ○: No second film peeling.

[0168] ×: The second film floats up and peels off.

[0169] (Determination of peel strength between the second film and resin layer at an ambient temperature of 40°C)

[0170] After cutting the laminated structures prepared in Examples 1-4 and Comparative Examples 1-2 into pieces 15 mm wide and 95 mm long, a 15 mm wide double-sided adhesive tape (Nicetack NW-K15, manufactured by NICHIBAN Co., Ltd.) was adhered along the length of the first film surface with the allowance remaining. Then, the allowance of the double-sided adhesive tape was cut in the same manner as the size of the laminated structure (15 mm wide and 95 mm long) to bond the double-sided adhesive tape to the surface of the first film for a glass epoxy board with a width of 15 mm, a length of 95 mm, and a thickness of 1.6 mm. Cuts were made along the length of the second film with a width of 15 mm, separated by widths of 10 mm and 5 mm. Then, a portion of the second film was peeled off, clamped, and placed in a constant temperature bath at 40°C for 5 minutes. The load at which the film peeled 30 mm from one end of the glass epoxy board along a 90-degree angle at a speed of 50 mm / min was measured. The peel strength between the second film and the resin layer at an ambient temperature of 40°C was then determined. The test used an AG-X thermostat manufactured by Shimadzu Corporation, and the constant temperature bath was a TCR2W-200T. The test results are shown in Table 3 below.

[0171] (Evaluation of the operability of the second film)

[0172] The laminated structures prepared in Examples 1-4 and Comparative Examples 1-2 were cut into pieces 10 cm wide and 30 cm long. Next, a hot plate set to 40°C was prepared and placed in contact with the second film of the laminated structure for 10 minutes. Afterward, the second film was peeled off in one go, and the presence or absence of resin layer damage was observed. The evaluation results are shown in Table 3 below. It should be noted that if the second film can be peeled off without resin layer damage, it can be said that the peelability between the resin layer and the second film at an ambient temperature of 40°C is good.

[0173] Evaluation Criteria:

[0174] 〇: No damage to the resin layer can be confirmed.

[0175] ×: Damage to the resin layer has been confirmed.

[0176] [Table 3]

[0177]

[0178] Table 3 shows that a resin layer with appropriate peel strength can produce a good laminated structure without the second film floating and peeling.

[0179] Then, using the various types of second films shown in Table 4, and by varying the thickness of the resin layer, the effects of the arithmetic mean surface roughness (Ra) of the second film (on the resin layer side) and the thickness of the resin layer on the peel strength between the second film and the resin layer and the operability of the second film were evaluated. The evaluation results are shown in Table 5 below. It should be noted that the resin composition of Example 4 was used as the resin composition.

[0180] [Table 4]

[0181]

[0182] E-201F: Biaxially stretched polypropylene film manufactured by Oji F-Tex Co., Ltd.

[0183] TN100: Release PET film manufactured by Toyobo Co., Ltd.

[0184] MA-411: Biaxially stretched polypropylene film manufactured by Oji F-Tex Co., Ltd.

[0185] MA-430: Biaxially stretched polypropylene film manufactured by Oji F-Tex Co., Ltd.

[0186] MAM-430: Biaxially stretched polypropylene film manufactured by Oji F-Tex Co., Ltd.

[0187] [Table 5]

[0188]

[0189] As shown in Table 5, in the case of the laminated structures of Comparative Examples 3 to 6, the peel strength between the second film and the resin layer at an ambient temperature of 40°C becomes greater than 1.5 N / cm, and the operability of the second film is problematic.

[0190] On the other hand, it was confirmed that the peel strength between the second film and the resin layer in the laminated structures of Examples 5 to 12 at an ambient temperature of 40°C is less than 1.5 N / cm, and the second film has good operability.

[0191] (Fabrication of a roll-shaped layered structure)

[0192] A 25 μm thick polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., "E5041") was prepared as the first film. The resin composition of Example 4 was uniformly coated onto the surface of the first film using a die-coating machine and dried at 80°C to 105°C (average 90°C) for 5 minutes to form a resin layer. Next, the second film shown in Table 6 was laminated onto the surface of the resin layer at 50°C under normal pressure to create a laminated structure. The resulting laminated structure was rolled into a roll (roll length 50 m). The resulting roll was slit into sections 247 mm wide to obtain a roll-shaped laminated structure. By adjusting the film thickness during coating, the arithmetic mean surface roughness Ra of the second film was varied to produce the roll-shaped laminated structures of Examples 13 to 18. Additionally, MA-411 was used as the second film to produce the roll-shaped laminated structure of Comparative Example 7. The structure of the prepared roll-shaped laminated structures is shown in Table 6.

[0193] [Table 6]

[0194]

[0195] E-201F: Biaxially stretched polypropylene film manufactured by Oji F-Tex Co., Ltd.

[0196] TN100: Release PET film manufactured by Toyobo Co., Ltd.

[0197] MA-411: Biaxially stretched polypropylene film manufactured by Oji F-Tex Co., Ltd.

[0198] (Evaluation of roll lamination properties)

[0199] The obtained roll-shaped laminated structure was mounted on a roller laminator (VA-770A type laminator manufactured by Taisei Laminator Co., Ltd.). The lamination conditions were: lamination roller temperature: 90°C, lamination pressure: 0.3 MPa, conveyor speed: 0.5 m / min, laminated structure roll-out tension: 20 N, and diaphragm roll-up tension: 15 N. While conveying the laminated structure, the second film was peeled off, and lamination was performed with the exposed resin layer surface onto a single-sided flexible printed circuit board with circuitry formed (circuit thicknesses of 18, 35, and 70 μm were prepared, and the substrate imide thickness was 25 μm). The peeling state of the second film was observed and evaluated according to the following criteria. The evaluation results are shown in Table 7.

[0200] Evaluation Criteria:

[0201] ◎: The following evaluation of 〇 can be more smoothly carried out.

[0202] 〇: Able to peel off.

[0203] ×: Cannot be peeled (cannot be laminated)

[0204] [Table 7]

[0205] Evaluation Project Example 13 Example 14 Example 15 Example 16, Example 17, Example 18, Comparative Example 7 Circuit thickness of the substrate [μm] 18 35 35 18 / 357035 Roller lamination ○ ○ ○ ◎◎◎×

[0206] Tables 5 and 7 show that the laminated structure with a peel strength of less than 1.5 N / cm for the second film at an ambient temperature of 40°C exhibits good roll lamination properties.

[0207] On the other hand, Comparative Example 7, where the peel force of the second film exceeded 1.5 N / cm, could not be peeled and could not be laminated.

[0208] (Determination of peel strength between the first film and resin layer at an ambient temperature of 40°C)

[0209] Regarding the determination of the peel strength between the first film and the resin layer at an ambient temperature of 40°C, the second film of the laminated structure of Example 1 was peeled off, and the exposed resin layer was adhered to a glass epoxy board with a width of 15 mm, a length of 95 mm, and a thickness of 1.6 mm using a vacuum laminator (Nikko-Materials Co., Ltd. CVP-300 laminator). Here, the lamination temperature was set to 70°C, the vacuum holding time was set to 20 seconds, and the pressurization time was set to 90 seconds.

[0210] Next, a cut was made along the length of the first film, with a width of 15 mm, separated by cuts of 10 mm and 5 mm. Then, a portion of the first film was peeled off, clamped, and placed in a constant temperature bath at 40°C for 5 minutes. The load at which the film was peeled 30 mm from one end of the length along a 90-degree angle at a speed of 50 mm / min was measured, and the peel strength between the first film and the resin layer at an ambient temperature of 40°C was determined. An AG-X thermostat manufactured by Shimadzu Corporation was used for the measurement, and a TCR2W-200T thermostat was used. The same measurements were performed on the laminated structures of Examples 2-4 and Comparative Examples 1 and 2. The measurement results are shown in Table 8.

[0211] It should be noted that the laminated structures of Examples 5-18 have the same type of first film and resin layer composition as the laminated structure of Example 4. Therefore, the peel strength between the first film and the resin layer is the same as that of Example 4 (2.0 N / cm). For the laminated structures of Comparative Examples 3-7, the second film could not be peeled off well, and the peel strength between the first film and the resin layer at an ambient temperature of 40°C could not be measured.

[0212] [Table 8]

[0213]

Claims

1. A layered structure, characterized in that, It consists of a first film, a resin layer, and a second film, in sequence. The resin layer comprises: (A) an alkali-soluble resin, (B) a multifunctional photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting resin. The second film is a film formed using thermoplastic resin. The arithmetic mean surface roughness Ra of the resin layer side surface in the second film is less than 0.1 μm. The peel strength between the second film and the resin layer at an ambient temperature of 40°C is 0.4~1.5 N / cm. The melt viscosity of the alkali-soluble resin (A) at 90°C is in the range of 100~1000 Pa·s. The alkali-soluble resin (A) having the said melt viscosity comprises: an alkali-soluble polyurethane resin having the said melt viscosity, an acid-modified epoxy acrylate resin having the said melt viscosity, or a combination thereof. The solid content of the alkali-soluble polyurethane resin having the aforementioned melt viscosity, the solid content of the acid-modified epoxy acrylate resin having the aforementioned melt viscosity, or a combination thereof, relative to 100% by mass of the solid content of the resin layer, are 5 to 50% by mass, respectively. The solid content of the (B) multifunctional photopolymerizable monomer is 10-40% by mass relative to 100% by mass of the solid content of the resin layer. The content of the photopolymerization initiator (C) is 0.1% to 40% by mass relative to 100% of the solid content of the resin layer. The equivalent ratio of the functional group of the alkali-soluble resin (A) to the functional group of the thermosetting resin (D) reacting with the functional group is 1:0.1 to 1:

10.

2. The laminated structure according to claim 1, characterized in that, The thickness of the resin layer is 5~100μm.

3. A cured product, characterized in that, It is obtained by curing the resin layer in the laminated structure according to claim 1 or 2.

4. An electronic component, characterized in that, It has the cured product as described in claim 3.

5. A method for forming a solidified material, characterized in that, The process includes the following steps: The process of peeling off the second film in the laminated structure according to claim 1 or 2, so that the resin layer is attached to the substrate on which the circuit is formed, and configuring the first film and the resin layer on the substrate; In the exposure process, a designated portion of the resin layer is irradiated with active energy rays through the first thin film; In the developing process, the first film is peeled off, and the areas in the resin layer that were not irradiated with active energy rays after the exposure process are removed. and In the curing process, the resin layer after the developing process is heated.

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