KR20230161432A - Laminated structure, cured resin layer in the laminate structure, electronic component, and method for forming the cured product - Google Patents

Abstract

[Problem] A laminated structure in which both the peelability and bonding properties of the resin layer and the second film are good even under the condition that the environmental temperature around the laminated structure rises to a certain temperature (in particular, about 40°C), and the development of the laminated structure. A cured product of the resin layer, an electronic component having the cured product, and a method of forming the cured product are provided.
[Solution] The laminated structure sequentially includes a first film, a resin layer, and a second film, and the resin layer includes (A) an alkali-soluble resin, (B) a polyfunctional photopolymerizable monomer, and (C) a photopolymerization initiator. and (D) a thermosetting resin, and the peeling strength of the second film and the resin layer at an environmental temperature of 40°C is 0.4 to 1.5 N/cm.

Description

Laminated structure, cured resin layer in the laminate structure, electronic component, and method for forming the cured product

The present invention relates to a laminated structure, a cured product of a resin layer in the laminated structure, an electronic component having the cured product, and a method of forming the cured product. In particular, the present invention relates to a laminated structure having good peelability and bonding properties between the resin layer and the second film, a cured product of the resin layer in the laminated structure, an electronic component having the cured product, and the formation of the cured product. It's about method.

An insulating film (solder resist) is formed on printed wiring boards used in various electronic devices. This insulating film is formed using, for example, a laminated structure including a first film, a resin layer, and a second film in that order. The method of forming an insulating film using this laminated structure includes a step of peeling the second film from the laminated structure, and through this step, an insulating film is finally formed on the circuit-formed substrate.

Cited Document 1 discloses an adhesive sheet with a protective film in which the relationship between the peeling strength of the protective film (second film) with respect to the resin composition layer and the peeling strength of the support (first film) with respect to the resin composition layer is specified.

Japanese Patent Publication No. 2018-123331

However, in the case of the adhesive sheet with a protective film described in Patent Document 1, since the peeling strength is a small value, there was a concern that when this adhesive sheet was rolled into a roll, there would be a problem that wrinkles would easily occur due to winding misalignment. That is, there still remains a problem in terms of adhesion between the resin layer and the second film (peel strength is inadequate).

In addition, for the laminated structure, considering the process of peeling the second film from the laminated structure, good peelability between the resin layer and the second film is required, and on the other hand, good bonding properties between the resin layer and the second film (e.g. , good bonding properties when the laminated structure is in roll form) are also required. In other words, it is important to obtain a laminated structure in which both of these conflicting properties are good.

In particular, depending on the laminating device, the environmental temperature around the laminated structure may rise to about 40°C due to radiant heat, and even under these conditions, the laminated structure has good peelability and bonding properties of the resin layer and the second film. It is important to get

The object of the present invention, made in view of the above problems, is to provide peelability and adhesion between the resin layer and the second film, especially under the condition that the environmental temperature around the laminated structure rises to a certain temperature (in particular, about 40°C). The object is to provide a laminated structure that is both good, a cured product of the resin layer in the laminated structure, an electronic component having the cured product, and a method of forming the cured product.

As a result of intensive study, the present inventor has found that, in a laminated structure including a first film, a resin layer containing a specific component, and a second film, the peeling strength of the second film and the resin layer at an environmental temperature of 40°C is within a specific range. By doing so, it was found that the above object can be achieved, and the present invention was completed.

That is, the above object is achieved by the present invention.

A laminated structure sequentially including a first film, a resin layer, and a second film,

The resin layer includes (A) an alkali-soluble resin, (B) a multifunctional photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting resin,

This can be achieved by a laminated structure wherein the peeling strength of the second film and the resin layer at an environmental temperature of 40°C is 0.4 to 1.5 N/cm.

According to a preferred form of the laminated structure according to the present invention, the thickness of the resin layer is 5 to 100 μm.

According to another preferred form of the laminated structure according to the present invention, the arithmetic mean surface roughness Ra of the surface on the resin layer side of the second film is 0.1 μm or less.

According to another preferred form of the laminated structure according to the present invention, the alkali-soluble resin (A) has a melt viscosity at 90°C in the range of 100 to 1,000 Pa·s.

According to another preferred form of the laminated structure according to the present invention, the alkali-soluble resin (A) having the above melt viscosity is an alkali-soluble urethane resin having the above melt viscosity, an acid-modified epoxy acrylate resin having the above melt viscosity, or Includes combinations of them.

According to another preferred form of the laminated structure according to the present invention, the solid content of the alkali-soluble urethane resin having the above melt viscosity, the solid content of the acid-modified epoxy acrylate resin having the above melt viscosity, or the solid content of a combination thereof is, Each is 5 to 50% by mass based on 100% by mass of solid content of the resin layer.

Additionally, the present invention is a cured product characterized by curing the resin layer in the laminated structure.

Furthermore, the present invention also relates to electronic components characterized by having the above-mentioned cured product.

In addition, the present invention

A step of peeling off the second film in the laminated structure, attaching the resin layer to a circuit-formed substrate, and disposing the first film and the resin layer on the substrate;

An exposure process of irradiating active energy rays through the first film to a predetermined portion of the resin layer,

A development process of peeling off the first film and removing an area not irradiated with active energy rays in the resin layer after the exposure process, and

A cured product forming process of heating the resin layer after the developing process.

It also relates to a method of forming a cured product comprising:

According to the present invention, in particular, even under the condition that the environmental temperature surrounding the laminated structure rises to a certain temperature (in particular, about 40 ° C.), both the peelability of the resin layer and the second film and their bonding properties are good. The object is to provide a structure, a cured product of a resin layer in the laminated structure, an electronic component having the cured product, and a method of forming the cured product.

The laminated structure of the present invention is a laminated structure that sequentially includes a first film, a resin layer, and a second film, wherein the resin layer includes (A) an alkali-soluble resin, (B) a multifunctional photopolymerizable monomer, and (C) It contains a photopolymerization initiator and (D) a thermosetting resin, and the peeling strength of the second film and the resin layer at an environmental temperature of 40°C is 0.4 to 1.5 N/cm. This configuration provides a laminated structure in which both the peelability and bonding properties of the resin layer and the second film are good, even under the condition that the environmental temperature surrounding the laminated structure rises to a certain temperature (in particular, about 40° C.). You can get it. Additionally, since the peel strength is 0.4 to 1.5 N/cm, winding misalignment is unlikely to occur in the roll-shaped laminated structure, and the generation of wrinkles can be prevented.

Between the first film and the resin layer, one or more other resin layers may be further included. This additionally included other resin layer may be the same as or different from the resin layer mainly disposed between the first film and the second film. That is, the resin composition for forming another resin layer may be the same as or different from the resin composition for forming the resin layer mainly disposed between the first film and the second film.

[First film]

The first film has a role of supporting the resin layer when laminating the resin layer in the laminated structure to the circuit-formed substrate, and when forming the resin layer, the resin composition for forming the resin layer is applied. It will happen. Examples of the first film include thermoplastic resins such as polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyimide films, polyamideimide films, polyethylene films, polytetrafluoroethylene films, polypropylene films, and polystyrene films. A film formed by can be used. Among these, polyester film can be suitably used from the viewpoint of heat resistance, mechanical strength, handleability, etc. The thickness of the first film is not particularly limited, but is preferably in the range of 10 to 150 ㎛, more preferably in the range of 15 to 100 ㎛, and even more preferably in the range of 20 to 75 ㎛, and selected appropriately depending on the application. do. A mold release treatment may be performed on the surface on which the resin layer of the first film is provided. Additionally, sputtering or ultra-thin copper foil may be formed on the surface of the first film where the resin layer is provided. As a commercial item, for example, Toyobo Co., Ltd. product "E5041" (polyethylene terephthalate film; thickness 25 micrometers) is mentioned.

[Peel strength of first film and resin layer]

The peeling strength of the first film and the resin layer at an environmental temperature of 40°C is preferably higher than the peeling strength of the second film and the resin layer at an environmental temperature of 40°C, and is more preferably 0.5 to 2.5 N/cm.

The peel strength of the first film and the resin layer is measured at an environmental temperature of 40°C in a 90° peel test based on JIS K6854-1:1999. As a testing device used in the 90° peel test, Autograph AG-X manufactured by Shimadzu Seisakusho can be used. This peeling strength can be measured at the average peeling strength at a peeling speed of 50 mm/min and a stroke of 35 mm.

Specifically, the laminated structure of the present invention is cut to a size of 15 mm in width and 95 mm in length, and then the second film is peeled off, and the exposed resin layer is placed on a glass epoxy plate with a width of 15 mm, a length of 95 mm, and a thickness of 1.6 mm. Attach using a vacuum laminator (Laminator CVP-300 manufactured by Nikko Materials Co., Ltd.). Here, the laminate temperature is 70°C, the vacuum holding time is 20 seconds, and the pressurizing time is 90 seconds.

Next, a cut is formed in the longitudinal direction so that the 15 mm width of the first film is divided into 10 mm width and 5 mm width. Subsequently, a part of the first film is peeled off, held with a holding tool, left in a constant temperature bath at 40°C for 5 minutes, and then 30 mm in a 90 degree direction with respect to the glass epoxy plate from one end in the longitudinal direction at a speed of 50 mm/min. The load when torn is measured, and the peeling strength of the first film and the resin layer at an environmental temperature of 40°C is determined. The thermostat uses TCR2W-200T.

[Resin layer]

The resin layer contains (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 to 100 μm, more preferably 10 to 90 μm, and even more preferably 25 to 85 μm. By setting it within this range, it is possible to meet the demand for thinning printed wiring boards. In addition, although printed wiring boards have various circuit thicknesses depending on the purpose, the laminated structure of the present invention can be sufficiently applied even to printed wiring boards with a large circuit thickness. The resin layer in the laminated structure of the present invention is a resin composition containing (A) an alkali-soluble resin, (B) a multifunctional photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting resin, on the first film. It is formed by applying and drying at 50 to 150°C for 1 to 30 minutes. Hereinafter, the components related to the resin composition for forming the resin layer will be described.

[(A) Alkali-soluble resin]

Alkali-soluble resin has an alkali-soluble group that is soluble in an aqueous alkaline solution. The alkali-soluble group is, for example, any one of a phenolic hydroxyl group, a thiol group, and a carboxyl group. Examples of the alkali-soluble resin include compounds having two or more phenolic hydroxyl groups, carboxyl group-containing resins, compounds having a phenolic hydroxyl group and a carboxyl group, and compounds having two or more thiol groups.

If the alkali-soluble resin is a carboxyl group-containing resin or a phenol resin, the adhesion to the substrate improves. In particular, if the alkali-soluble resin is a carboxyl group-containing resin, developability is excellent. The carboxyl group-containing resin is preferably a carboxyl group-containing photosensitive resin having an ethylenically unsaturated group, but it may be a carboxyl group-containing resin that does not have an ethylenically unsaturated group.

Specific examples of the carboxyl group-containing resin include the compounds listed below (which may be either oligomers or polymers).

(1) Carboxyl group-containing resin obtained by copolymerization of an unsaturated carboxylic acid such as (meth)acrylic acid and an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth)acrylate, and isobutylene.

(2) Diisocyanates such as aliphatic diisocyanate, branched aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate, carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, and polycarbonate-based polyol and polyether-based polyol. , polyester polyol, polyolefin polyol, acrylic polyol, bisphenol A alkylene oxide adduct diol, carboxyl group-containing urethane resin by polyaddition reaction of diol compounds such as compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups. .

(3) Diisocyanate compounds such as aliphatic diisocyanate, branched aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate, polycarbonate-based polyol, polyether-based polyol, polyester-based polyol, polyolefin-based polyol, acrylic polyol, and bisphenol. A urethane resin containing a terminal carboxyl group, which is obtained by reacting an acid anhydride at the terminal of a urethane resin through a polyaddition reaction of a diol compound such as an A-based alkylene oxide adduct diol and a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

(4) Diisocyanate and 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, and biphenol-type epoxy resin. A urethane resin containing a carboxyl group obtained by polyaddition reaction of (meth)acrylate or its partial acid anhydride modified product, a dialcohol compound containing a carboxyl group, and a diol compound.

(5) During the synthesis of the resin of (2) or (4) above, a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule such as hydroxyalkyl (meth)acrylate is added to form the terminal. (meth)acrylated urethane resin containing a carboxyl group.

(6) During the synthesis of the resin of (2) or (4) above, an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate, etc., has one isocyanate group and one or more (meth)acryloyl groups in the molecule. A urethane resin containing a carboxyl group whose ends have been (meth)acrylated by adding a compound.

(7) Carboxyl group-containing resin (acid-modified epoxy acrylic) obtained by reacting (meth)acrylic acid with a polyfunctional epoxy resin and adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the hydroxyl group present in the side chain. rate resin).

(8) Carboxyl group-containing resin (acid-modified epoxy acrylic) obtained by reacting (meth)acrylic acid with a polyfunctional epoxy resin in which the hydroxyl group of the bifunctional epoxy resin was further epoxidized with epichlorohydrin, and dibasic acid anhydride was added to the hydroxyl group generated. rate resin).

(9) A polyester resin containing a carboxyl group obtained by reacting dicarboxylic acid with a polyfunctional oxetane resin and adding a dibasic acid anhydride to the primary hydroxyl group generated.

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

(11) A polybasic acid anhydride is added to the reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate, and reacting a monocarboxylic acid containing an unsaturated group. Carboxyl group-containing resin obtained by reaction.

(12) Epoxy compounds having multiple epoxy groups in one molecule, compounds having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule such as p-hydroxyphenethyl alcohol, and unsaturated compounds such as (meth)acrylic acid. A product obtained by reacting a group-containing monocarboxylic acid and 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, and adipic anhydride. Carboxyl group-containing resin.

(13) In addition to the carboxyl group-containing resins described in (1) to (12) above, one epoxy group and one or more molecules such as glycidyl (meth)acrylate, α-methylglycidyl (meth)acrylate, etc. A carboxyl group-containing resin obtained by adding a compound having a (meth)acryloyl group.

Compounds having a phenolic hydroxyl group include, for example, compounds having a biphenyl skeleton, a phenylene skeleton, or both skeletons, phenol, orthocresol, paracresol, metacresol, 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, phloroglucinol, etc. are used to synthesize phenolic resins having various skeletons.

Additionally, compounds having a phenolic hydroxyl group include, for example, phenol novolak resin, alkylphenol novolak resin, bisphenol A novolak resin, dicyclopentadiene type phenol resin, Xylok type phenol resin, terpene-modified phenol resin, and polyvinyl phenol resin. Known and commonly used phenol resins such as phenols, bisphenol F, bisphenol S type phenol resins, poly-p-hydroxystyrene, condensates of naphthol and aldehydes, and condensates of dihydroxynaphthalene and aldehydes can be mentioned.

As an alkali-soluble resin, one type of the above compound can be used individually or in combination of two or more types.

The melt viscosity of the alkali-soluble resin at 90°C is preferably in the range of 100 to 1,000 Pa·s, more preferably in the range of 120 to 700 Pa·s, and even more preferably in the range of 150 to 500 Pa·s. By setting this range, it not only becomes easier to adjust the peel strength of the second film and the resin layer to the range of 0.4 to 1.5 N/cm at an environmental temperature of 40°C, but also makes it easier to laminated the resin layer to the circuit-formed substrate at 90°C. Air mixing (air bubble mixing) in the shoulder portion of the circuit can be suppressed. The melt viscosity measurement method follows the melt viscosity measurement method below. Additionally, if the measuring device to be used is difficult to obtain due to a discontinued product or the like, another device having equivalent performance can be used, and the same applies to other measuring devices in this specification. The above range regarding the melt viscosity of the alkali-soluble resin can be controlled, for example, by the melt viscosity of the main component constituting the alkali-soluble resin and/or the compounding amount of the main component.

(Method for measuring melt viscosity)

The alkali-soluble resin was diluted with propylene glycol monomethyl ether acetate to obtain a resin solution, which was potted onto fluororesin (Aplex 50 HK NT manufactured by aGC) and heated in an oven at 100°C for 10 hours to form a solution with a thickness of approximately 1 mm and a diameter. A 25 mm dried resin plate is formed. Next, melt viscosity is measured under the following measurement conditions using RS-6000 manufactured by Thermo Scientific.

(Measurement conditions for melt viscosity)

Sensor: Φ20mm parallel plate type

Temperature increase rate: 5℃/min

Measurement frequency: 1Hz

Measuring pressure: 3Pa

As the main component of the alkali-soluble resin having the above-described melt viscosity, an alkali-soluble resin having a (meth)acryloyl group having the above-mentioned melt viscosity is preferable, and specifically, an alkali-soluble urethane resin (as the urethane resin, more specifically, The urethane resins of (2) to (6) above are preferred), acid-modified epoxy acrylate resins having the above melt viscosity (the acid-modified epoxy acrylate resins include, more specifically, the alkali resins of (7) and (8) above. soluble resins are preferred), or combinations thereof. The range of the melt viscosity of the main components constituting the alkali-soluble resin (for example, alkali-soluble urethane resin and acid-modified epoxy acrylate resin) can be controlled according to the technical knowledge of those skilled in the art.

The solid content of the alkali-soluble urethane resin having the melt viscosity, the solid content of the acid-modified epoxy acrylate resin having the melt viscosity, or the solid content of the combination thereof is preferably, respectively, relative to 100% by mass of the solid content of the resin layer. It is 5 to 50 mass%. In addition, in the case of a combination of an alkali-soluble urethane resin having the melt viscosity and an acid-modified epoxy acrylate resin having the melt viscosity, the solid content of the alkali-soluble urethane resin having the melt viscosity and the acid-modified epoxy having the melt viscosity are The ratio of the solid content of the acrylate resin 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 bonding properties of the resin layer and the second film can be improved.

The acid value of the alkali-soluble resin is suitably in the range of 40 to 200 mgKOH/g, and more preferably in the range of 45 to 120 mgKOH/g. If the acid value of the alkali-soluble resin is 40 mgKOH/g or more, alkali development becomes easy.

On the other hand, it is preferable because it becomes easier to draw a normal cured material pattern of 200 mgKOH/g or less.

The weight average molecular weight of the alkali-soluble resin varies depending on the resin skeleton, but is preferably in the range of 1,500 to 150,000, and more preferably 1,500 to 100,000. When the weight average molecular weight is 1,500 or more, tack-free performance is good, the moisture resistance of the coating film after exposure is good, film reduction during development can be suppressed, and degradation of resolution can be suppressed.

On the other hand, when the weight average molecular weight is 150,000 or less, developability is good and storage stability is also excellent.

[(B) Multifunctional photopolymerizable monomer]

As the multifunctional photopolymerizable monomer, it is a compound having two or more ethylenically unsaturated groups in the molecule, and photopolymerizable oligomers and photopolymerizable vinyl monomers, which are known and commonly used photocurable monomers, can be used.

Examples of photopolymerizable oligomers include unsaturated polyester-based oligomers and (meth)acrylate-based oligomers. As (meth)acrylate-based oligomers, epoxy (meth)acrylates such as phenol novolac epoxy (meth)acrylate, cresol novolac epoxy (meth)acrylate, and bisphenol-type epoxy (meth)acrylate, and urethane (meth)acrylate. Acrylate, epoxyurethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, polybutadiene modified (meth)acrylate, etc. can be mentioned. In addition, in this specification, (meth)acrylate is a general term for acrylates, methacrylates, and mixtures thereof, and the same applies to other similar indications.

Photopolymerizable vinyl monomers include known and commonly used ones, such as polyfunctional allyl compounds such as triallyl isocyanurate, diallyl phthalate, and diallyl isophthalate; Ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate , alkylene polyol poly(meth)acrylates such as pentaerythritol tetra(meth)acrylate and dipentaerythritol hexa(meth)acrylate; Polyoxyalukirene glycol polys such as diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, ethoxylated trimethylolpropane triacrylate, and propoxylated trimethylolpropane tri(meth)acrylate. (meth)acrylates; Poly(meth)acrylates such as hydroxypivalic acid neopentyl glycol ester di(meth)acrylate; Isocyanurate-type poly(meth)acrylates, such as tris[(meth)acryloxyethyl]isocyanurate, are mentioned. These can be used individually or in combination of two or more, depending on the required characteristics. As a commercial item, for example, "Aronix M-350" (trimethylolpropane EO modified triacrylate) manufactured by Toago Se Co., Ltd.

The solid content of the polyfunctional photopolymerizable monomer is preferably 10 to 40% by mass, for example, based on 100% by mass of the solid content of the resin layer.

[(C) Photopolymerization initiator]

As the photopolymerization initiator, any photopolymerization initiator known as a photopolymerization initiator or a photo radical generator can be used.

As a photopolymerization initiator, for example, 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, bis-(2,4, Bisacylphosphine oxides such as 6-trimethylbenzoyl)-phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine methyl ester, 2-methylbenzoyldiphenylphosphine oxide, P monoacylphosphine oxides such as valoylphenylphosphinic acid isopropyl ester and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; 1-Hydroxy-cyclohexylphenylketone, 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, 2-hydroxy-2-methyl-1-phenylpropane- Hydroxyacetophenones such as 1-one; Benzoins such as benzoin, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and benzoin n-butyl ether; Benzoin alkyl ethers; Benzophenones such as benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bisdiethylaminobenzophenone; Acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl- 1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2- Acetophenones such as (dimethylamino)-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone and N,N-dimethylaminoacetophenone; Thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-di Thioxanthone such as isopropylthioxanthone; Anthraquinones such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone; Ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; Benzoic acid esters such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethylbenzoate, and p-dimethylbenzoic acid ethyl ester; 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-car oxime esters such as basol-3-yl]-, 1-(O-acetyloxime); Bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium, bis(cyclopentadienyl)- Titanocenes such as bis[2,6-difluoro-3-(2-(1-phil-1-yl)ethyl)phenyl]titanium; Phenyl disulfide 2-nitrofluorene, butyloin, anisoin ethyl ether, azobisisobutyronitrile, tetramethylthiuram disulfide, etc. are mentioned. The photopolymerization initiator may be used individually by 1 type, or may be used in combination of 2 or more types. Among them, monoacylphosphine oxides and oxime esters are preferable, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H -carbazol-3-yl]-, 1-(O-acetyloxime) is more preferable.

The content of the photopolymerization initiator is preferably 0.1 to 40% by mass, more preferably 0.3 to 20% by mass, based on 100% by mass of solid content of the resin layer.

[(D) Thermosetting resin]

The resin layer preferably contains a thermosetting resin. The thermosetting resin may be any resin that hardens by heating and exhibits electrical insulation properties, and examples include epoxy compounds, oxetane compounds, melamine resins, and silicone resins. In particular, in the present invention, epoxy compounds and oxetane compounds can be suitably used, and these may be used together.

As the epoxy compound, known and common compounds having one or more epoxy groups can be used, and among them, compounds having two or more epoxy groups are preferable. For example, monoepoxy compounds such as butyl glycidyl ether, phenyl glycidyl ether, and glycidyl (meth)acrylate, bisphenol A type epoxy resin, bisphenol S type epoxy resin, and bisphenol F type. Epoxy resin, phenol novolac type epoxy resin, cresol novolak type epoxy resin, alicyclic epoxy resin, trimethylolpropane polyglycidyl ether, phenyl-1,3-diglycidyl ether, biphenyl-4,4' -Diglycidyl ether, 1,6-hexanediol diglycidyl ether, diglycidyl ether of ethylene glycol or propylene glycol, sorbitol polyglycidyl ether, tris(2,3-epoxypropyl)isocyanu Compounds having two or more epoxy groups in one molecule, such as triglycidyltris(2-hydroxyethyl)isocyanurate, can be mentioned. These can be used individually or in combination of two or more, depending on the required characteristics.

Moreover, as an epoxy resin, for example, jER828, jER834, jER1001, jER1004 manufactured by Mitsubishi Chemical Corporation, EPICLON 840, 850, 850-S, 1050, 2055 manufactured by DIC Corporation, and EPOTOT YD-011 manufactured by Nittetsu Chemical & Materials Corporation. , YD-013, YD-127, YD-128, D.E.R.317, D.E.R.331, D.E.R.661, D.E.R.664 manufactured by Dow Chemical Co., Ltd., sumi-epoxy ESA-011, ESA-014, ELA-115, ELA manufactured by Sumitomo Chemical Co., Ltd. Bisphenol A type epoxy resins such as -128 (all brand names); jERYL903 manufactured by Mitsubishi Chemical Corporation, EPICLON 152, 165 manufactured by DIC Corporation, EPOTOT YDB-400, YDB-500 manufactured by Nittetsu Chemical & Materials Corporation, D.E.R.542 manufactured by Dow Chemical Corporation, Sumi-Epoxy ESB-400 manufactured by Sumitomo Chemical Corporation. Brominated epoxy resins such as , ESB-700 (all brand names); jER152, jER154 manufactured by Mitsubishi Chemical Corporation, D.E.N.431, D.E.N.438 manufactured by Dow Chemical Corporation, EPICLON N-730, N-770, N-865 manufactured by DIC Corporation, Epotot YDCN-701, YDCN- manufactured by Nittetsu Chemical & Materials Corporation. 704, EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306, NC-3000, NC-3000L manufactured by Nippon Kayaku, Sumi-epoxy ESCN-195X, ESCN-220 manufactured by Sumitomo Chemical. , YDCN-700-2, YDCN-700-3, YDCN-700-5, YDCN-700-7, YDCN-700-10, YDCN-704 YDCN-704A manufactured by Nittetsu Chemical & Materials, and EPICLON N manufactured by DIC. Novolak-type epoxy resins such as -680, N-690, and N-695 (all brand names); Bisphenol F-type epoxy resins such as EPICLON 830 manufactured by DIC, jER807 manufactured by Mitsubishi Chemical Corporation, and EPOTOT YDF-170, YDF-175, and YDF-2004 manufactured by Nittetsu Chemical & Materials Corporation (all brand names); Hydrogenated bisphenol A type epoxy resins such as Epotot ST-2004, ST-2007, and ST-3000 (brand name) manufactured by Nittetsu Chemical & Materials, and YX8034 manufactured by Mitsubishi Chemical Corporation; glycidylamine-type epoxy resins such as jER604 manufactured by Mitsubishi Chemical Corporation, Epotot YH-434 manufactured by Nittetsu Chemical & Materials Corporation, and Sumi-Epoxy ELM-120 manufactured by Sumitomo Chemical Corporation (all brand names); Hidanto doll epoxy resin; Alicyclic epoxy resins such as Celoxide 2021 manufactured by Daicel Corporation (all brand names); Trihydroxyphenylmethane type epoxy resins such as YL-933 manufactured by Mitsubishi Chemical Corporation, EPPN-501 and EPPN-502 manufactured by Nippon Kayaku Corporation (all brand names); bixylenol-type or biphenol-type epoxy resins such as YL-6056, YX-4000, and YL-6121 (all brand names) manufactured by Mitsubishi Chemical Corporation, or mixtures thereof; bisphenol S-type epoxy resins such as EBPS-200 manufactured by Nippon Kayaku Corporation, EPX-30 manufactured by ADEKA Corporation, and EXA-1514 (brand name) manufactured by DIC Corporation; Bisphenol A novolak-type epoxy resins such as jER157S (brand name) manufactured by Mitsubishi Chemical Corporation; tetraphenylolethane type epoxy resins such as jERYL-931 manufactured by Mitsubishi Chemical Corporation (all brand names); Heterocyclic epoxy resins such as TEPIC manufactured by Nissan Chemical Industries, Ltd. (all brand names); diglycidyl phthalate resins such as Blemmer DGT manufactured by Nichiyu Corporation; Tetraglycidyl xylenoyl ethane resin, such as ZX-1063 manufactured by Nittetsu Chemical &Materials; Naphthalene skeleton-containing epoxy resins such as ESN-190 and ESN-360 manufactured by Nittetsu Chemical & Materials, and HP-4032, EXA-4750 and EXA-4700 manufactured by DIC Corporation; Epoxy resins having a dicyclopentadiene skeleton such as HP-7200 and HP-7200H manufactured by DIC Corporation; Glycidyl methacrylate copolymerization epoxy resins such as CP-50S and CP-50M manufactured by Nichiyu Corporation; Also, a copolymer epoxy resin of cyclohexylmaleimide and glycidyl methacrylate; CTBN modified epoxy resins (for example, YR-102, YR-450, etc. manufactured by Nittetsu Chemical & Materials), etc. are included, but are not limited to these.

These epoxy resins may be used individually, or may be used in combination of two or more types.

Next, the oxetane compound is explained. The following general formula (I),

A specific example of an oxetane compound containing an oxetane ring represented by (wherein R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) is 3-ethyl-3-hydroxymethyloxetane (manufactured by Toagosei Co., Ltd.) OXT-101), 3-ethyl-3-(phenoxymethyl)oxetane (OXT-211, manufactured by Toago Chemicals Co., Ltd.), 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane (OXT-212, manufactured by Toago Chemicals Co., Ltd.) ), 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene (OXT-121 manufactured by Toago Se Co., Ltd.), bis(3-ethyl-3-oxetanylmethyl)ether ( OXT-221) manufactured by Toa Kosei Co., Ltd., etc. may be mentioned. Additionally, phenol novolac type oxetane compounds and the like can also be mentioned. These oxetane compounds may be used in combination with the epoxy compound, or may be used individually.

The solid content of the thermosetting resin is preferably an equivalent ratio of the functional group (alkali-soluble group such as carboxyl group) of the alkali-soluble resin and the functional group (thermosetting group such as epoxy group) of the thermosetting resin that can react with this functional group, preferably 1:0.1. The ratio is preferably 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, developability is good and a fine cured product pattern can be formed.

[Second film]

The second film is provided on the side of the resin layer opposite to the first film for the purpose of preventing dust and the like from adhering to the surface of the resin layer of the laminated structure and improving handling properties. As the second film, for example, a film formed of the thermoplastic resin exemplified in the first film can be used. Among these, polyester films, polyethylene films, polypropylene films, and films whose surfaces have been subjected to release treatment are preferable. The thickness of the second film is not particularly limited, but is preferably in the range of 10 to 150 ㎛, more preferably in the range of 12.5 to 100 ㎛, and even more preferably in the range of 15 to 50 ㎛, and selected appropriately depending on the application. do. A mold release treatment may be performed on the surface on which the resin layer of the second film is provided.

The second film preferably has an arithmetic mean surface roughness Ra of 0.1 μm or less. By setting this range (by smoothing the surface of the second film), the second film can be properly affixed to the resin layer having high adhesiveness. That is, the peelability of the resin layer and the second film can be improved.

Hereinafter, a specific method of measuring the arithmetic mean surface roughness Ra will be described. Arithmetic average surface roughness Ra can be measured using a shape measurement laser microscope (for example, VK-X100 manufactured by Keyence Corporation). After starting the main body (control unit) of the shape measurement laser microscope (VK-X100) and the VK observation application (VK-H1VX, manufactured by Keyence Corporation), the sample to be measured (second film) is placed on the x-y stage. Turn the lens revolver on the microscope unit (VK-X110, manufactured by Keyence Corporation) to select an objective lens with a magnification of 10x, and roughly adjust the focus and brightness in the image observation mode of the VK observation application (VK-H1VX). . Manipulate the x-y stage so that the part of the sample surface to be measured is at the center of the screen. Change the objective lens from 10x magnification to 50x magnification, and use the autofocus function in the image observation mode of the VK observation application (VK-H1VX) to focus on the surface of the sample. You can select the simple mode in the shape measurement tab of the VK observation application (VK-H1VX), press the measurement start button, measure the surface shape of the sample, and obtain a surface image file. The VK analysis application (VK-H1XA, manufactured by Keyence Corporation) is started, the obtained surface image file is displayed, and then tilt correction is performed. Additionally, the horizontal observation and measurement range in measuring the surface shape of the sample is set to 270 μm. Display the line roughness window, select JIS B0601-1994 in the parameter setting area, select a horizontal line from the measurement line button, display a horizontal line anywhere in the surface image, and press the OK button to obtain the arithmetic mean surface roughness. Obtain the value of Ra. Additionally, horizontal lines are displayed at four other locations in the surface image to obtain the numerical value of each arithmetic average surface roughness Ra. The average value of the five obtained values is calculated, respectively, and is set as the arithmetic average surface roughness Ra of the sample surface.

When using a thermoplastic resin film as the second film having the arithmetic mean surface roughness Ra, filler is added to the resin when forming the film, the film surface is blasted, hairline processing, mat coating, or By chemical etching or the like, the surface can be formed into a predetermined shape, and a thermoplastic resin film having the above-mentioned arithmetic mean surface roughness Ra can be obtained. For example, when adding a filler to a resin, the arithmetic mean surface roughness Ra can be controlled by adjusting the particle diameter or addition amount of the filler. Additionally, in the case of blast processing, the arithmetic mean surface roughness Ra can be controlled by adjusting processing conditions such as blast material and blast pressure. Commercially available products include, for example, “E-201F” (biaxially stretched polypropylene film) manufactured by Oji Ftex Corporation, “TN100” and “TN200” (release-treated polyethylene terephthalate film) manufactured by Toyobo Corporation, or “Ceraphil” manufactured by Toray Corporation. PJ271” and “Ceraphil PJ111” (mold release treated polyethylene terephthalate film).

[Peel strength of second film and resin layer]

The peeling strength of the second film and the resin layer at an environmental temperature of 40°C is 0.4 to 1.5 N/cm. The combination of this range of peeling strength and the resin layer having a specific component allows peeling of the resin layer and the second film, especially under the condition that the environmental temperature around the laminated structure rises to a certain temperature (in particular, about 40°C). Both stability and bonding properties can be improved. The peel strength of the second film and the resin layer was measured at an environmental temperature of 40°C in a 90° peel test based on JIS K6854-1:1999. As a testing device used in the 90° peel test, Autograph AG-X manufactured by Shimadzu Seisakusho can be used. This peeling strength can be measured at the average peeling strength at a peeling speed of 50 mm/min. and a stroke of 35 mm.

Specifically, after cutting the laminated structure of the present invention to 15 mm in width and 95 mm in length, a 15 mm wide double-sided tape (“Nystack NW-K15” manufactured by Nichiban Co., Ltd.) is generously applied to the surface of the first film in the longitudinal direction. After attaching, cut the extra part of the double-sided tape so that it is the same as the size of the laminated structure (width 15 mm, length 95 mm) and stick it on the surface of the first film against a glass epoxy plate with a width of 15 mm, a length of 95 mm, and a thickness of 1.6 mm. Attach a piece of double-sided tape. A cut is formed in the longitudinal direction so that the width of 15 mm of the second film is divided into a width of 10 mm and a width of 5 mm. Subsequently, a part of the second film is peeled off, held with a holding tool, left in a constant temperature bath at 40° C. for 5 minutes, and then tilted 90 degrees from one end in the longitudinal direction with respect to the glass epoxy plate at a speed of 50 mm/min and a stroke of 35 mm. The load when torn 30 mm in each direction is measured, and the peeling strength of the second film and the resin layer at an environmental temperature of 40°C is determined. The thermostat uses TCR2W-200T.

The above range (0.4 to 1.5 N/cm) of the peel strength of the second film and the resin layer can be additionally adjusted mainly by changing the melt viscosity at 90°C of the alkali-soluble resin or adjusting its blending amount, for example. For example, it can be controlled by considering 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.

On the other hand, the peeling strength of the first film and the resin layer at an environmental temperature of 40°C is preferably 1.6 to 2.5 N/cm. Within this range, the effect of preventing destruction of the resin layer during peeling of the second film can be obtained. In addition, the peeling strength of the first film and the resin layer at an environmental temperature of 40°C can be measured by a method similar to the above.

[Inorganic filler]

The resin layer may contain an inorganic filler. As the inorganic filler, it is preferable to contain a surface-treated inorganic filler. Here, surface treatment of the inorganic filler means treatment to improve compatibility with the resin component. The surface treatment of the inorganic filler is preferably a surface treatment capable of introducing a curing reactive group to the surface of the inorganic filler.

The inorganic filler is not particularly limited and includes commonly known fillers such as silica, crystalline silica, Neuburg silica, aluminum hydroxide, glass powder, talc, clay, magnesium carbonate, calcium carbonate, natural mica, synthetic mica, and aluminum hydroxide. Inorganic fillers such as barium sulfate, barium titanate, iron oxide, non-fibrous glass, hydrotalcite, mineral wool, aluminum silicate, calcium silicate, and zinc oxide can be used. Among them, silica is preferable, and spherical silica is more preferable because it has a small surface area and is difficult to become the origin of cracks because stress is distributed throughout. Examples of commercially available products include “Aluminum Hydroxide” manufactured by Showa Denko Co., Ltd.

The content of the inorganic filler is preferably 1 to 300% by mass, more preferably 5 to 150% by mass, based on 100% by mass of solid content of the resin layer.

[Other Random Ingredients]

The resin layer may be blended with other curing ingredients or additives commonly known in the field of electronic materials. Other curing components include cyanate ester resin, active ester resin, maleimide compound, and alicyclic olefin polymer. Other additives include non-silicone release agents, photobase generators, heat curing catalysts, colorants, organic solvents, thermal polymerization inhibitors, ultraviolet absorbers, silane coupling agents, plasticizers, flame retardants, antistatic agents, anti-aging agents, antibacterial and fungicide agents, and anti-foaming agents. , leveling agents, thickeners, adhesion imparting agents, thixotropic imparting agents, photoinitiation aids, sensitizers, thermoplastic resins, organic fillers, mold release agents, surface treatment agents, dispersants, dispersion aids, surface modifiers, stabilizers, phosphors, etc. .

[Method of forming laminated structure]

When forming a laminated structure, first, a resin composition containing (A) an alkali-soluble resin, (B) a multifunctional photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting resin is prepared using a comma coater, blade coater, etc. 1 Apply a uniform thickness onto the film. After that, the applied resin composition can be usually dried at a temperature of 40 to 130°C for 1 to 30 minutes to form a resin layer. Thereafter, a second film is bonded to the surface of the resin layer opposite to the first film to form a laminated structure. Additionally, a resin layer may be formed by applying and drying the resin composition on the second film, and then the first film may be bonded together. Additionally, when the laminated structure is long, it may be wound into a roll to form a roll-shaped laminated structure. The roll-shaped laminated structure may be cut to a predetermined width as needed.

[Method for forming cured product of resin layer on circuit board]

The method of forming a cured resin layer on a circuit board (specifically, the method of forming a cured resin layer in the laminate structure) includes the following steps:

A step of peeling off the second film in the laminated structure, attaching the resin layer to a circuit-formed substrate, and disposing the first film and the resin layer on the substrate;

An exposure process of irradiating active energy rays through the first film to a predetermined portion of the resin layer,

A development process of peeling off the first film and removing an area not irradiated with active energy rays in the resin layer after the exposure process, and

A cured product forming process of heating the resin layer after the developing process.

It can be done by a method including.

(Process of attaching a resin layer to a circuit board)

As a step of attaching the resin layer to the substrate on which the circuit is formed, it is preferable to peel the second film from the resin layer using a vacuum laminator or the like and bond it under pressure and heating. By using such a vacuum laminator, the laminated structure is brought into close contact with the surface of the circuit board on which the circuit is formed, so there is no mixing of air bubbles, and the hole filling property of the concave portion of the circuit board surface is also improved. Pressurizing conditions are preferably about 0.1 to 2.0 MPa, and heating conditions are preferably 40 to 120°C.

(Exposure process)

In the exposure process, the resin layer containing a photopolymerization initiator can be photocured by, for example, irradiating light under conditions where the exposure amount is 50 mJ/cm ² to 1000 mJ/cm ² . Light irradiation is performed by irradiation of active energy rays such as ultraviolet rays, electron beams, and actinic rays. The method of irradiating active energy rays to a predetermined portion may be a method of selectively irradiating active energy rays through a photomask forming a predetermined pattern, or may be applied directly using a drawing device (for example, directly using CAD data from a computer). You can also use a laser direct imaging device that creates images with a laser.

(Development process)

In the development process, after peeling of the first film, the unexposed portion is removed by alkaline development to form a cured film in the form of a negative pattern. As a developing method, a known method such as dipping can be used. Additionally, as a developing solution, sodium carbonate, potassium carbonate, potassium hydroxide, amines, imidazoles such as 2-methylimidazole, alkaline aqueous solutions such as tetramethylammonium hydroxide aqueous solution (TMAH), or a mixture thereof can be used.

(Hured product formation process)

In the cured product formation step, the resin layer after photocuring is thermoset by using a known heating means, for example, a heating furnace such as a hot stove, an electric furnace, or an infrared induction heating furnace. As heating conditions, it is preferable to heat at 150°C to 170°C for 5 to 120 minutes.

Examples of the substrate on which the circuit is formed include films containing glass polyimide, polyimide, polyethylene terephthalate, liquid crystal polymer, polycarbonate, etc., but are not limited to these and a known and commonly used circuit board can be used.

[Hured product of resin layer]

The cured product of the resin layer on the circuit board (i.e., the cured product obtained by curing the resin layer without the first film and the second film in the laminated structure) has excellent flexibility, and is therefore particularly useful for flexible printed wiring boards. It is also suitable as a cover layer or solder resist (insulating cured film).

[Electronic components characterized by having a cured product of the resin layer]

The present invention also provides electronic components having a cured resin layer. In the present invention, electronic components refer to components used in electronic circuits, and include active components such as printed wiring boards, especially flexible printed wiring boards, transistors, light-emitting diodes, and laser diodes, as well as passive components such as condensers, inductors, and connectors. do. The cured product of the resin layer of the present invention is suitable as an insulating cured film.

Example

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to the following examples. In addition, in the following, “part” and “%” are all based on mass unless otherwise specified.

(Synthesis of alkali-soluble urethane resin A-1)

In a 2L flask equipped with a stirring device and a reflux tube, 378.0 g of a bisphenol A-type epoxy compound (“828” manufactured by Mitsubishi Chemical Corporation; bifunctional bisphenol A-type epoxy resin, epoxy equivalent: 189 g/equivalent) and acrylic acid (molecular weight: 72.06) 142.7 g, 2.94 g of 2,6-di-tert-butyl-p-cresol as a thermal polymerization inhibitor, and 1.53 g of triphenylphosphine as a reaction catalyst were added, and the acid value of the reaction solution was 0.5 at a temperature of 98°C. The reaction was allowed to reach mgKOH/g or less, and epoxy acrylate compound (a) (theoretical molecular weight: 510.7) was obtained.

Next, 594.0 g of carbitol acetate and 105.5 g of dimethylolpropionic acid (b) (molecular weight: 134.16) as reaction solvents were added to this reaction liquid, and the temperature was raised to 45°C. To this solution, 264.7 g of isophorone diisocyanate (c) (molecular weight: 222.28) was added dropwise little by little so that the reaction temperature did not exceed 65°C. After the dropwise addition was completed, the temperature was raised to 80°C and the reaction was performed for 6 hours until the isocyanate group absorption around 2250 cm ^-1 disappeared according to an infrared absorption spectrum measurement method, and the reaction was further performed at a temperature of 98°C for 2 hours. In this way, a resin solution (alkali-soluble urethane resin A-1) containing 60% by mass of alkali-soluble urethane resin (A) as a solid content concentration was obtained. As a result of measuring the acid value, it was 28.9 mgKOH/g (solid acid value: 48.2 mgKOH/g).

(Synthesis of alkali-soluble urethane resin A-2)

In a reaction vessel equipped with a stirring device, thermometer, and condenser, polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol as a compound having two or more alcoholic hydroxyl groups (Asahi Kasei Chemicals Co., Ltd.) ) agent "TJ5650J", number average molecular weight 800) 3600 g (4.5 mol), 814 g (5.5 mol) of dimethylolbutanoic acid, and 186 g (1.6 mol) of 2-hydroxyethyl acrylate as a molecular weight regulator (reaction terminator) were added. Next, 2009 g (10.8 mol) of trimethylhexamethylene diisocyanate as an isocyanate compound without an aromatic ring was added, heated to 60°C while stirring, stopped, and when the temperature in the reaction vessel began to decrease, heated again to 80°C. Stirring was continued, and the reaction was terminated after confirming that the absorption spectrum of the isocyanate group (2280 cm ^-1 ) disappeared in the infrared absorption spectrum. Next, carbitol acetate was added so that the solid content was 60% by mass, and a viscous liquid carboxyl group-containing alkali-soluble urethane resin (alkali-soluble urethane resin A-2) containing a diluent was obtained. The solid acid value of the obtained carboxyl group-containing alkali-soluble urethane resin A-2 was 49.8 mgKOH/g.

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

380 parts of bisphenol F-type epoxy resin (epoxy equivalent weight 950 g/eq, softening point 85°C) 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 dissolved in 98.5% NaOH at 70°C while stirring. 60.9 parts were added over 100 minutes. After addition, reaction was further performed at 70°C for 3 hours. After completion of the reaction, 250 parts of water were added and water washing was performed. After oil-water separation, most of the dimethyl sulfoxide and excess unreacted epichlorohydrin were distilled and recovered from the oil layer under reduced pressure, and the reaction product containing the remaining subsalt and dimethyl sulfoxide was dissolved in 750 parts of methyl isobutyl ketone. , 10 parts of 30% NaOH were also added and reacted at 70°C for 1 hour. After completion of the reaction, it was washed twice with 200 parts of water. After oil-water separation, methyl isobutyl ketone was distilled and recovered from the oil layer to obtain epoxy resin (a) with an epoxy equivalent weight of 310 g/eq and a softening point of 69°C. Calculating from the epoxy equivalent weight of the obtained epoxy resin (a), about 5 of the 6.2 alcoholic hydroxyl groups in the 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, heated and stirred at 90°C, and dissolved. The obtained solution was once cooled to 60°C, 72 parts (1 mole) of acrylic acid, 0.5 parts of methylhydroquinone, and 2 parts of triphenylphosphine were added, heated to 100°C, and reacted for about 60 hours to obtain an acid value of 0.2 mgKOH/. g reactant was obtained. 140 parts (0.92 mol) of tetrahydrophthalic anhydride was added to this, heated to 90°C, reaction was performed, and acid-modified epoxy acrylate resin (acid-modified epoxy acrylate resin A-3) was obtained. The solid content concentration of the obtained acid-modified epoxy acrylate resin A-3 was 62% by mass, and the solid acid value (mgKOH/g) was 100.

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

220 parts of a cresol novolak-type epoxy resin (“EPICLON N-695” manufactured by DIC Corporation; epoxy equivalent: 220) was placed in a four-necked flask equipped with a stirrer and a reflux condenser, and 214 parts of carbitol acetate were added and heated to dissolve. Next, 0.1 part of hydroquinone as a polymerization inhibitor and 2.0 parts of dimethylbenzylamine as a reaction catalyst were added. This mixture was heated to 95 to 105°C, 72 parts of acrylic acid was added dropwise, and reacted for 16 hours. This reaction product was cooled to 80 to 90°C, 106 parts of tetrahydrophthalic anhydride was added, it was allowed to react for 8 hours, and after cooling, it was taken out.

The acid-modified epoxy acrylate resin (acid-modified epoxy acrylate resin A-4) obtained in this way had a solid content of 65%, a solid acid value of 100 mgKOH/g, and a weight average molecular weight Mw of about 3,500.

(Measurement of melt viscosity of alkali-soluble resin obtained in synthesis example)

Resin solutions for alkali-soluble urethane resin A-1, alkali-soluble urethane resin A-2, acid-modified epoxy acrylate resin A-3, and acid-modified epoxy acrylate resin A-4 were mixed with a fluororesin (Aplex 50 HK NT manufactured by aGC). ) and heated in an oven at 100°C for 10 hours to form a dried resin plate with a thickness of about 1 mm and a diameter of 25 mm. Melt viscosity was measured using RS-6000 manufactured by Thermo Scientific under the following measurement conditions. The results of this measurement are shown in Table 1 below.

(Measurement conditions for melt viscosity)

Sensor: Φ20mm parallel plate type

Temperature increase rate: 5℃/min

Measurement frequency: 1Hz

Measuring pressure: 3Pa

(Examples 1 to 18 and Comparative Examples 1 to 7)

A laminated structure was produced by the following method.

(Preparation of resin composition for forming resin layer)

According to the formulation shown in Table 2, the components described in Examples and Comparative Examples were mixed, premixed with a stirrer, and then kneaded with a three-roll mill to prepare a resin composition for forming a resin layer in a laminated structure. did. Unless otherwise specified, the values in the table are mass% and solid content.

(Production of laminated structure)

As a first film, a polyethylene terephthalate film (“E5041” manufactured by Toyobo Co., Ltd.) with a thickness of 25 μm was prepared. The resin composition obtained above was applied onto the film and dried at a temperature of 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 Ftex Co., Ltd.) was bonded as a second film, and Examples 1 to 4 and comparison in which a resin layer was disposed between the first film and the second film. The laminated structures of Examples 1 and 2 were obtained.

※1 Trimethylolpropane EO modified triacrylate (manufactured by Toagosei Co., Ltd.)

※2 2,4,6-trimethylbenzoyldiphenylphosphine oxide

※3 Biphenyl aralkyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.)

※4 Aluminum hydroxide (made by Showa Denko)

(Adhesion between second film and resin layer)

In the case of manufacturing the above-described laminated structure using a roll laminator (VA-770 manufactured by Taisei Laminator Co., Ltd.) with the laminate roll temperature set to 50°C and the pressing force set to 0.2 MPa, the second film was bonded to the resin layer. The attached state of the second film was evaluated. The results of this evaluation are shown in Table 3 below.

○: No peeling of the second film.

×: Floating and peeling of the second film occur.

(Measurement of peel strength of the second film and resin layer at an environmental temperature of 40°C)

After cutting the laminated structures produced in Examples 1 to 4 and Comparative Examples 1 to 2 to a width of 15 mm and a length of 95 mm, a double-sided tape (Nystack NW-K15, manufactured by Nichiban Co., Ltd.) with a width of 15 mm was applied to the surface of the first film. 」) in the longitudinal direction, then cut the excess part of the double-sided tape to be the same as the size of the laminated structure (width 15 mm, length 95 mm), and attach it to a glass epoxy plate with a width of 15 mm, a length of 95 mm, and a thickness of 1.6 mm. The double-sided tape attached to the surface of the first film was adhered. A cut was formed in the longitudinal direction so that the 15 mm width of the second film was divided into 10 mm width and 5 mm width. Subsequently, a part of the second film is peeled off, held with a holding tool, left in a constant temperature bath at 40° C. for 5 minutes, and then 30 mm in a 90 degree direction with respect to the glass epoxy plate from one end in the longitudinal direction at a speed of 50 mm/min. The load when torn was measured, and the peeling strength of the second film and the resin layer at an environmental temperature of 40°C was determined. For the measurement, AG-X manufactured by Shimadzu Seisakusho Co., Ltd. was used, and TCR2W-200T was used as a thermostat. The results of this measurement are shown in Table 3 below.

(Evaluation of handleability of the second film)

The laminated structures produced in Examples 1 to 4 and Comparative Examples 1 to 2 were cut to a width of 10 cm and a length of 30 cm. Next, a hot plate set to 40°C was prepared, and the second film of the laminated structure was left in contact with the hot plate for 10 minutes. After that, the second film was torn off at once, and the presence or absence of destruction of the resin layer was observed. The results of this evaluation are shown in Table 3 below. Additionally, if the second film can be peeled without the resin layer being destroyed, it can be said that the peelability of the resin layer and the second film at an environmental temperature of 40°C is good.

Evaluation standard:

○: Destruction of the resin layer was not confirmed.

×: Destruction of the resin layer is confirmed.

As is clear from Table 3, a resin layer having an appropriate peel strength can obtain a good laminated structure without lifting or peeling of the second film.

Subsequently, using various types of second films shown in Table 4 and changing the thickness of the resin layer, in each case, the peeling strength of the second film and the resin layer and the handleability of the second film were determined. The influence of the arithmetic average surface roughness (Ra) of the second film (on the resin layer side) and the thickness of the resin layer was evaluated. The results of this evaluation are shown in Table 5 below. Additionally, as the resin composition, the resin composition of Example 4 was used.

E-201F: Biaxially stretched polypropylene film manufactured by Oji Ftex Co., Ltd.

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

MA-411: Biaxially stretched polypropylene film manufactured by Oji Ftex Co., Ltd.

MA-430: Biaxially stretched polypropylene film manufactured by Oji Ftex Co., Ltd.

MAM-430: Biaxially stretched polypropylene film manufactured by Oji Ftex Co., Ltd.

As is clear from Table 5, in the case of the laminated structures of Comparative Examples 3 to 6, the peeling strength of the second film and the resin layer at an environmental temperature of 40°C is greater than 1.5 N/cm, and there is a problem with the handleability of the second film. There was.

On the other hand, the peeling strength of the second film and the resin layer in the laminated structures of Examples 5 to 12 at an environmental temperature of 40°C was 1.5 N/cm or less, and it was confirmed that the second film had good handleability.

(Production of roll-shaped laminated structure)

As a first film, a polyethylene terephthalate film (“E5041” manufactured by Toyobo Co., Ltd.) with a thickness of 25 μm was prepared. The resin composition of Example 4 was uniformly applied to the surface of the first film using a die coater 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 on the surface of the resin layer at 50°C under normal pressure to produce a laminated structure. The obtained laminated structure was wound into a roll (winding length 50 m). The obtained roll-shaped body was slitted to a width of 247 mm to obtain a roll-shaped laminated structure. Roll-shaped laminated structures of Examples 13 to 18 were produced by adjusting the film thickness at the time of application and changing the arithmetic mean surface roughness Ra of the second film. Additionally, a roll-shaped laminated structure of Comparative Example 7 was produced using MA-411 as the second film. Table 6 shows the composition of the manufactured roll-shaped laminated structure.

E-201F: Biaxially stretched polypropylene film manufactured by Oji Ftex Co., Ltd.

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

MA-411: Biaxially stretched polypropylene film manufactured by Oji Ftex Co., Ltd.

(Evaluation of roll laminability)

The obtained roll-shaped laminated structure was set on a roll laminator (“VA-770A type laminator” manufactured by Taisei Laminator Co., Ltd.). The lamination conditions were lamination roll temperature: 90°C, lamination pressure: 0.3 MPa, conveyance speed: 0.5 m/min, laminated structure unwinding tension: 20 N, and separator winding tension: 15 N. The second film is peeled off while transporting the laminated structure, and the surface where the resin layer is exposed is used as a single-sided flexible printed wiring board on which a circuit is formed (three types of circuit thickness = 18, 35, and 70 ㎛ are prepared, base imide thickness = 25 ㎛). Lamination was performed so that it was in contact with . The peeling state of the second film at this time was observed and evaluated based on the following criteria. The evaluation results are shown in Table 7.

Evaluation standard:

◎: Peeling off more smoothly than the evaluation of ○ below.

○: Peeling off.

×: No peeling (not laminated).

As is clear from Tables 5 and 7, the laminated structure in which the peeling strength of the second film at an environmental temperature of 40°C was 1.5 N/cm or less showed good roll lamination properties.

On the other hand, Comparative Example 7, in which the peeling force of the second film exceeded 1.5 N/cm, could not be peeled and was not laminated.

(Measurement of peel strength of the first film and the resin layer at an environmental temperature of 40°C)

Regarding the measurement of the peel strength of the first film and the resin layer at an environmental temperature of 40°C, the second film of the laminated structure of Example 1 was peeled and the exposed resin layer was peeled off with a glass having a width of 15 mm, a length of 95 mm, and a thickness of 1.6 mm. It was attached to the epoxy plate using a vacuum laminator (Laminator CVP-300 manufactured by Nikko Materials Co., Ltd.). Here, the laminate temperature was 70°C, the vacuum holding time was 20 seconds, and the pressurization time was 90 seconds.

Next, a cut was formed in the longitudinal direction so that the 15 mm width of the first film was divided into 10 mm width and 5 mm width. Subsequently, a part of the first film is peeled off, held with a holding tool, left in a constant temperature bath at 40°C for 5 minutes, and then 30 mm in a 90 degree direction with respect to the glass epoxy plate from one end in the longitudinal direction at a speed of 50 mm/min. The load when torn was measured, and the peeling strength of the first film and the resin layer at an environmental temperature of 40°C was determined. For the measurement, AG-X manufactured by Shimadzu Seisakusho Co., Ltd. was used, and TCR2W-200T was used as a thermostat. The laminated structures of Examples 2 to 4 and Comparative Examples 1 and 2 were similarly measured. The measurement results are shown in Table 8.

In addition, since the type of the first film and the composition of the resin layer of the laminated structures of Examples 5 to 18 are the same as those of the laminated structure of Example 4, the peel strength of the first film and the resin layer is the same as that of Example 4. (2.0N/cm). For the laminated structures of Comparative Examples 3 to 7, the second film could not be peeled off satisfactorily, and the peel strength of the first film and the resin layer at an environmental temperature of 40°C could not be measured.

Claims (9)

A laminated structure sequentially including a first film, a resin layer, and a second film,
The resin layer includes (A) an alkali-soluble resin, (B) a multifunctional photopolymerizable monomer, (C) a photopolymerization initiator, and (D) a thermosetting resin,
A laminate structure, characterized in that the peeling strength of the second film and the resin layer at an environmental temperature of 40° C. is 0.4 to 1.5 N/cm. The laminated structure according to claim 1, wherein the resin layer has a thickness of 5 to 100 ㎛. The laminated structure according to claim 1 or 2, wherein the arithmetic mean surface roughness Ra of the surface on the resin layer side of the second film is 0.1 μm or less. The laminated structure according to any one of claims 1 to 3, wherein the alkali-soluble resin (A) has a melt viscosity at 90°C in the range of 100 to 1,000 Pa·s. The method of claim 4, wherein the alkali-soluble resin (A) having the melt viscosity includes an alkali-soluble urethane resin having the melt viscosity, an acid-modified epoxy acrylate resin having the melt viscosity, or a combination thereof. Laminated structure. The solid content of the resin layer according to claim 5, wherein the solid content of the alkali-soluble urethane resin having the melt viscosity, the solid content of the acid-modified epoxy acrylate resin having the melt viscosity, or the combination thereof are each 100% solid content of the resin layer. A laminated structure characterized in that it is 5 to 50% by mass based on mass%. A cured product obtained by curing the resin layer in the laminated structure according to any one of claims 1 to 6. An electronic component comprising the cured product according to claim 7. The second film in the laminate structure according to any one of claims 1 to 6 is peeled off, the resin layer is attached to a circuit-formed substrate, and the first film and the resin layer are applied to the substrate. process of placing,
An exposure process of irradiating active energy rays through the first film to a predetermined portion of the resin layer,
A development process of peeling off the first film and removing an area not irradiated with active energy rays in the resin layer after the exposure process, and
A cured product forming process of heating the resin layer after the developing process.
A method of forming a cured product comprising: