JP2023150460A - Method for manufacturing circuit board - Google Patents

Abstract

To provide a method for manufacturing a circuit board having a smoothed surface formed of an upper surface of a circuit and an upper surface of a hardened material of a resin layer and further excellent insulation reliability about the hardened material of the resin layer embedding a gap between circuits.SOLUTION: A method for manufacturing a circuit board includes the steps of: preparing a laminate structure including a resin layer containing a carboxy group-containing resin; laminating the resin layer of the laminate structure on the circuit board; generating a hardened material of the resin layer by exposing the resin layer laminated on the circuit board; developing the circuit board including a hardened material of a post-exposure resin layer; and heating the circuit board including a hardened material of a post-development resin layer. The carboxy group-containing resin contains a carboxy group-containing resin having an urethane skeleton. A water absorption coefficient about the hardened material of the post-exposure resin layer is 1.0 to 4.0.

Description

The present invention uses a laminated structure having a resin layer, the carboxyl group-containing resin contained in the resin layer includes a carboxyl group-containing resin having a urethane skeleton, and the water absorption rate of the cured product of the resin layer after exposure is 1.0 to 4.0, and relates to a method for manufacturing a circuit board.

As shown in FIG. 1, a circuit board 10 includes a substrate 1, a copper circuit 2 provided on the substrate, and a cured resin layer 3 provided to fill the gaps between the copper circuits. It has been known. In this circuit board, as shown in FIG. 1, the height of the copper circuit and the height of the cured resin layer are the same, that is, the upper surface of the copper circuit and the upper surface of the cured resin layer are It is desirable that the surface be smooth when viewed from the side. The reason for this is that if the height of the cured resin layer becomes higher than the height of the copper circuit, for example, the surface formed by the top surface of the copper circuit and the top surface of the cured resin layer On the other hand, there arises an inconvenience that another new member cannot be properly arranged or a desired solder resist cannot be further formed. On the other hand, if the height of the cured resin layer becomes lower than the height of the copper circuit, that is, if the cured resin layer becomes depressed, for example, solder may enter the depression. This is because there are disadvantages in that the insulation reliability is deteriorated, and the insulation reliability is easily cracked when another new member is laminated.

As a prior art invention for smoothing the surface formed by the upper surface of a copper circuit and the upper surface of a cured resin layer, Patent Document 1 discloses a flexible insulating film, an adhesive layer, and an electrically conductive film. A flexible circuit board is disclosed in which a cured product of ultraviolet curable ink is provided in the gaps between the electrically conductive circuits. The cured product of this ultraviolet curable ink is obtained by filling the gap between the electrically conductive circuits with the ultraviolet curable ink, and then irradiating the ink with ultraviolet rays from the flexible insulating film side.

Japanese Patent Application Publication No. 7-73739

However, in the invention described in Patent Document 1, the ultraviolet rays are irradiated to the ultraviolet curable ink through the flexible insulating film and the adhesive layer, so even if the exposure amount is adjusted, the ultraviolet rays are There is a risk that the upper surface of the ink will not be uniformly irradiated, and as a result, it is difficult to smooth the surface formed by the upper surface of the circuit and the upper surface of the cured resin layer.

In addition to the smooth surface formed by the top surface of the above circuit and the top surface of the cured resin layer, the cured resin layer that fills the gaps between the circuits also has excellent insulation reliability. It is desirable that

Therefore, an object of the present invention is to smooth the surface formed by the upper surface of the circuit and the upper surface of the cured resin layer, and further improve the insulation reliability of the cured resin layer that fills the gaps between the circuits. An object of the present invention is to provide an excellent method for manufacturing a circuit board.

As a result of intensive studies, the present inventors have focused on using a laminated structure including a resin layer instead of using a liquid curable resin composition as in the invention described in Patent Document 1, and Furthermore, as a result of paying attention to the type of carboxyl group-containing resin contained in the resin layer in the laminated structure and the water absorption rate of the cured product after exposure, the inventors found that the above problems could be solved, and completed the present invention.

That is, the above object, according to the present invention,
preparing a laminated structure having a resin layer containing a carboxyl group-containing resin, a photocurable compound having no carboxyl group, a photopolymerization initiator, an inorganic filler, and a thermosetting resin;
Laminating the resin layer of the laminated structure on a circuit board;
a step of exposing the resin layer laminated on the circuit board to produce a cured product of the resin layer;
Developing a circuit board having a cured product of the resin layer after exposure;
A method for manufacturing a circuit board, the method comprising: heating a circuit board having a cured product of the resin layer after development,
The carboxyl group-containing resin includes a carboxyl group-containing resin having a urethane skeleton, and the water absorption rate of the cured product of the resin layer after exposure is 1.0 to 4.0. This can be achieved by a circuit board manufacturing method.

According to a preferred embodiment of the method for manufacturing a circuit board according to the present invention, the carboxyl group-containing resin having a urethane skeleton is a carboxyl group-containing resin having an urethane skeleton having an acid value in the range of 20 to 70 mgKOH/g, and/or Contains a carboxyl group-containing resin having a urethane skeleton with an acid value in the range of 80 to 150 mgKOH/g.

According to a preferred embodiment of the method for manufacturing a circuit board according to the present invention, the resin layer of the laminated structure contains a flame retardant.

According to the method for manufacturing a circuit board of the present invention, the surface formed by the upper surface of the circuit and the upper surface of the cured resin layer is smoothed, and the insulation of the cured resin layer that fills the gaps between the circuits is further improved. A method for manufacturing a circuit board with excellent reliability can be provided.

FIG. 3 is a schematic cross-sectional side view showing a state in which the surface formed by the upper surface of the circuit and the upper surface of the cured resin layer is smoothed. FIG. 3 is a schematic cross-sectional side view showing a state in which the surface formed by the upper surface of the circuit and the upper surface of the cured resin layer is not smoothed.

The method for manufacturing a circuit board of the present invention includes a step of preparing a laminated structure having a resin layer, a step of laminating the resin layer of the laminated structure on a circuit board, and a step of laminating the resin layer on the circuit board. A step of exposing a layer to light to produce a cured product of the resin layer, a step of developing a circuit board having the cured product of the resin layer after exposure, and a circuit board having the cured product of the resin layer after development. and a step of heating.
Each step can be performed under known conditions. An example of each step will be explained below.

[Step of preparing a laminated structure having a resin layer]
(Laminated structure)
The laminated structure used in the present invention preferably has a resin layer and also a first film (also referred to as a support or carrier film). This laminated structure can be obtained by coating a curable resin composition on a first film and drying it using a known drying means to form a resin layer. In some cases, in order to prevent dust from adhering to the surface of the resin layer of the laminated structure and to improve handling, a second film (protective film) may be added to the surface of the resin layer opposite to the first film. It is also possible to provide a film (also called a cover film).

(first film)
The first film has a role of supporting the resin layer of the laminated structure. As this first film, a plastic film is generally used, and for example, a polyester film such as polyethylene terephthalate (PET), a polyimide film, a polyamide-imide film, a polypropylene film, a polystyrene film, etc. can be used. The thickness of the first film is preferably in the range of 10 to 150 μm.

(resin layer)
By exposing and developing the resin layer, the surface formed by the upper surface of the circuit and the upper surface of the cured product of the resin layer is smoothed, and the cured product is provided between the circuits of the circuit board. Note that each component contained in the resin layer will be explained after each step is explained.

[Step of laminating the resin layer of the laminated structure on the circuit board]
The step of stacking can include a laminating step.
In the lamination process, the resin layer and the first film that make up the laminated structure are pressed against the circuit board under vacuum at a lamination temperature within a specific range, with the resin layer facing the circuit board. . By applying this pressure, the resin layer and the first film are laminated on the circuit board, and the resin layer is embedded between the circuits.
The lamination process can be performed using a vacuum laminator (for example, Laminator CVP-300 (fully automatic 2-stage laminator) manufactured by Nikko Materials Co., Ltd.). Here, in the present invention, under vacuum is preferably a state obtained by maintaining the vacuum state for an additional 10 to 40 seconds after reaching a vacuum state of preferably 4.0 hPa or less. The lamination temperature is preferably 60 to 110°C. The press pressure is preferably 0.3 to 0.5 MPa. The pressing time is preferably 10 to 120 seconds.
Note that the second lamination step may be performed successively if necessary. In the second lamination step, for example, the circuit board is opened to atmospheric pressure, the lamination temperature is set to 60 to 110° C., and the resin layer and the first film laminated on the circuit board are further pressurized. The second lamination step can be performed using the same vacuum laminator as above. Under atmospheric pressure means a standard atmospheric pressure (1013 hPa) and a pressure state in which extreme pressurization or extreme pressure reduction is not performed, and is, for example, 992 to 1033 hPa. The pressing pressure is, for example, 6.0 to 10.0 kgf/cm ² and the pressing time is, for example, 10 to 120 seconds.
Note that the circuit material may be any conductive material such as copper, silver, or gold.

[Process of exposing the resin layer laminated on the circuit board]
In the exposure step, the resin layer is irradiated with light in a predetermined pattern to photocure the resin layer between the circuits, leaving the resin layer on the circuits in an uncured state. The exposure amount of light irradiation is preferably 250 to 500 mJ/cm ² . The environmental temperature of the circuit board on which the resin layer and the first film are laminated (ambient temperature of the circuit board on which the resin layer and the first film are laminated) during exposure is preferably 10 to 40°C. The light irradiation is performed by irradiation with active energy rays such as ultraviolet rays, electron beams, and actinic rays. As a method of irradiating active energy rays to a predetermined portion, a method of selectively irradiating active energy rays through a photomask formed with a predetermined pattern may be used, or a method of irradiating active energy rays selectively through a photomask on which a predetermined pattern is formed, or a method using a direct drawing device (for example, a method using a direct laser using CAD data from a computer). A laser direct imaging device (which draws images) may also be used. Exposure can be done through the first film. However, the exposure may be performed after peeling the first film from the resin layer.

[Step of developing a circuit board having a cured resin layer after exposure]
In the developing step, the resin layer exposed to light in a predetermined pattern is developed. That is, in the development step, after the first film is peeled off, the uncured resin layer on the circuits can be removed by development with an alkaline aqueous solution, and a cured product can be formed only between the circuits. Examples of the developing method include known methods such as spray development. In addition, as a developer, an alkaline aqueous solution (for example, 1% by mass aqueous sodium carbonate solution, potassium carbonate, potassium hydroxide, amines, imidazoles such as 2-methylimidazole, tetramethylammonium hydroxide aqueous solution (TMAH)), Alternatively, a mixture of these can be used. The temperature of the developer is preferably 25 to 35°C, the development time is preferably 40 to 90 seconds, and the spray pressure of the developer is preferably 0.1 to 0.3 MPa.

[Step of heating the circuit board having the cured resin layer after development]
After the development process, a thermosetting process is performed. In the heat curing step, the curing temperature is preferably 150 to 170°C, and the curing time is preferably 30 to 90 minutes. In the heat curing step, known equipment can be used.

[Optional process]
After the development step, an optional water rinsing step and/or an optional ultraviolet irradiation step can be performed. In the water rinsing step, the water temperature is preferably 20-30°C, the spray pressure is preferably 0.05-0.15 MPa, and the rinsing time is preferably 30-120 seconds. In the ultraviolet irradiation step, the amount of ultraviolet irradiation is preferably 1 to 2 J/cm ² .

[Each component contained in the resin layer]
The resin layer contains a carboxyl group-containing resin, a photocurable compound that does not have a carboxyl group, a photopolymerization initiator, an inorganic filler, and a thermosetting resin. Moreover, the resin layer can also contain a flame retardant.
Each component contained in the resin layer will be explained below.

[Carboxyl group-containing resin]
As the carboxyl group-containing resin, various conventionally known resins having a carboxyl group in the molecule can be used, but this carboxyl group-containing resin must include a carboxyl group-containing resin having a urethane skeleton. be. The carboxyl group-containing resin may or may not have an ethylenically unsaturated double bond in its molecule, but in particular, a carboxyl group-containing photosensitive resin having an ethylenically unsaturated double bond in its molecule is , is preferable from the viewpoint of photocurability and development resistance. When the molecule contains an ethylenically unsaturated double bond, the carboxyl group-containing resin corresponds to a photocurable resin. Preferably, the ethylenically unsaturated double bond is derived from acrylic acid or methacrylic acid or derivatives thereof. When using only a carboxyl group-containing resin that does not have an ethylenically unsaturated double bond, it is necessary to use a photopolymerizable compound that does not have a carboxyl group, which will be described later, in order to make the composition photocurable. be.

In the present invention, considering that the surface formed by the upper surface of the circuit and the upper surface of the cured resin layer tends to be smooth, the acid value of the carboxyl group-containing resin should be in the range of 20 to 150 mgKOH/g. is preferred.

The weight average molecular weight of the carboxyl group-containing resin varies depending on the resin skeleton, but is generally in the range of 2,000 to 150,000, preferably in the range of 5,000 to 100,000. By using a carboxyl group-containing resin having a weight average molecular weight of 2,000 or more, the tack-free performance of the resin layer can be improved. Further, by using a carboxyl group-containing resin having a weight average molecular weight of 150,000 or less, developability and storage stability can be improved.

The content of the carboxyl group-containing resin is preferably 20 to 70% by mass based on the total mass of the resin layer in terms of solid content.

(Carboxyl group-containing resin with urethane skeleton)
Specific examples of the carboxyl group-containing resin having a urethane skeleton include the following resins (which may be either oligomers or polymers). The following resins may be used alone or in combination of two or more. Note that in this specification, (meth)acrylate is a term that collectively refers to acrylate, methacrylate, and mixtures thereof, and the same applies to other similar expressions.
(1) Diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, polycarbonate polyols, and polyethers. Carboxyl group-containing photosensitive urethane produced by polyaddition reaction of diol compounds such as polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A-based alkylene oxide adduct diols, and compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups. resin.

(2) Diisocyanate and bifunctional epoxy resins such as bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, bixylenol epoxy resin, and biphenol epoxy resin ( A carboxyl group-containing photosensitive urethane resin produced by a polyaddition reaction of meth)acrylate or its partially modified acid anhydride, a carboxyl group-containing dialcohol compound, and a diol compound.

(3) During the synthesis of the resin of (1) or (2) above, a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as hydroxyalkyl (meth)acrylate, is added, and the terminal ( meth)acrylated carboxyl group-containing photosensitive urethane resin.

(4) During the synthesis of the resin of (1) or (2) above, one isocyanate group and one or more (meth)acryloyl groups are added in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate. A carboxyl group-containing photosensitive urethane resin that is terminally (meth)acrylated by adding a compound that has a carboxyl group.

(5) A carboxyl group-containing photosensitive urethane resin obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule to the resins (1) to (4) above.

As the carboxyl group-containing resin having a urethane skeleton, it is preferable to use a bisphenol A type or bisphenol F type carboxyl group-containing urethane resin.

In the above carboxyl group-containing resin having a urethane skeleton, the carboxyl group-containing resin having a urethane skeleton (hereinafter referred to as urethane skeleton) has an acid value in the range of 20 to 70 mgKOH/g (preferably in the range of 30 to 60 mgKOH/g). carboxyl group-containing resin A) having an acid value of 80 to 150 mgKOH/g (preferably 90 to 120 mgKOH/g) (hereinafter referred to as a carboxyl group-containing resin having a urethane skeleton) Preference is given to using carboxyl group-containing resins B). In the present invention, the acid value of the carboxyl group-containing resin means the acid value of the solid content of the resin.
Since the carboxyl group-containing resin B having a urethane skeleton has a higher acid value, a cleaner and smoother surface can be obtained. Therefore, when using only carboxyl group-containing resin B having a urethane skeleton as the carboxyl group-containing resin having a urethane skeleton, the surface formed by the top surface of the circuit and the top surface of the cured resin layer can be made smoother. It can be done.
When using both carboxyl group-containing resin A having a urethane skeleton and carboxyl group-containing resin B having a urethane skeleton, the mass of carboxyl group-containing resin A having a urethane skeleton and carboxyl group-containing resin B having a urethane skeleton The ratio (carboxyl group-containing resin A having a urethane skeleton: carboxyl group-containing resin B having a urethane skeleton) is preferably 1:0.01 to 1:100, more preferably 1:0.1 to 1:10. .
Note that the specific acid value of the carboxyl group-containing resin having a urethane skeleton can be obtained based on the information on the acid value of each resin contained in the carboxyl group-containing resin having a urethane skeleton, and in this specification, , acid value and weight average molecular weight are values measured by the following methods.
<Method for measuring acid value>
About 0.5 g of carboxyl group-containing resin is taken, completely dissolved in 50 ml of 2-butoxyethanol, and titrated with 0.1N ethanolic potassium hydroxide solution to calculate the acid value using the following formula.
Acid value (mgKOH/g) = {N×f×56100×(V-BL}}/(1000×W)
W: Sample amount (g)
N: concentration of potassium hydroxide solution (mol/l)
f: titer V: titer volume (ml)
BL: Blank titration <method for measuring weight average molecular weight (Mw)>
The weight average molecular weight (Mw) is determined by gel permeation chromatography (GPC) (polystyrene standard) using the following measuring device and measuring conditions.
Measuring device: “Waters 2695” manufactured by Waters
Detector: “Waters2414” manufactured by Waters, RI (differential refractometer)
Column: Waters “HSPgel Column, HR MB-L, 3μm, 6mm x 150mm” x 2 + Waters “HSPgel Column, HR1, 3μm, 6mm x 150mm” x 2
Measurement condition:
Column temperature: 40℃
RI detector setting temperature: 35℃
Developing solvent: Tetrahydrofuran Flow rate: 0.5ml/min Sample amount: 10μl
Sample concentration: 0.5wt%

Examples of commercially available carboxyl group-containing resins having a urethane skeleton include SN-172 (acid value 45 mgKOH/g) manufactured by Nippon Kayaku Co., Ltd. and UXE-3002 (acid value 100 mgKOH/g) manufactured by Nippon Kayaku Co., Ltd. g).

The content of the carboxyl group-containing resin having a urethane skeleton is preferably 20 to 80% by mass, more preferably 40 to 65% by mass, based on the total mass of the carboxyl group-containing resin, in terms of solid content.

(Carboxyl group-containing resin without urethane skeleton)
The carboxyl group-containing resin can include carboxyl group-containing resins that do not have a urethane skeleton as well as carboxyl group-containing resins that have a urethane skeleton.
Specific examples of carboxyl group-containing resins that do not have a urethane skeleton include the following resins (which may be either oligomers or polymers).

(1) A carboxyl group-containing resin obtained by copolymerizing an unsaturated carboxylic acid such as (meth)acrylic acid with an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth)acrylate, or isobutylene ( Examples of lower alkyl (meth)acrylates include methyl (meth)acrylate, etc.).

(2) A carboxyl group-containing photosensitive resin obtained by reacting (meth)acrylic acid with a bifunctional or higher polyfunctional epoxy resin and adding a dibasic acid anhydride to the hydroxyl group present in the side chain.

(3) A carboxyl group-containing photosensitive material in which (meth)acrylic acid is reacted with a polyfunctional epoxy resin in which the hydroxyl groups of a bifunctional epoxy resin are further epoxidized with epichlorohydrin, and a dibasic acid anhydride is added to the resulting hydroxyl groups. sex resin.

(4) A bifunctional oxetane compound is reacted with a dicarboxylic acid such as adipic acid, phthalic acid, hexahydrophthalic acid, etc., and the resulting primary hydroxyl group is converted to a dibase such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, etc. Carboxyl group-containing polyester resin with acid anhydride added.

(5) An epoxy resin having multiple epoxy groups in one molecule, a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenethyl alcohol, and (meth) Maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, adipine are reacted with an unsaturated group-containing monocarboxylic acid such as acrylic acid, and the alcoholic hydroxyl group of the resulting reaction product is A carboxyl group-containing photosensitive resin obtained by reacting polybasic acid anhydrides such as acids.

(6) Reaction obtained by reacting a reaction product obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide with an unsaturated group-containing monocarboxylic acid. A carboxyl group-containing photosensitive resin obtained by reacting a product with a polybasic acid anhydride.

(7) Obtained by reacting a reaction product obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate with an unsaturated group-containing monocarboxylic acid. A carboxyl group-containing photosensitive resin obtained by reacting a reaction product with a polybasic acid anhydride.

(8) A carboxyl group-containing photosensitive resin obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule to the resins (1) to (7) above.

Specific examples of carboxyl group-containing resins that do not have a urethane skeleton include carboxyl group-containing epoxy (meth)acrylate resins that have a biphenyl skeleton and bisphenol A-type or bisphenol F-type carboxyl group-containing epoxy (meth)acrylate resins. Among these, carboxyl group-containing epoxy (meth)acrylate resins having a biphenyl skeleton are particularly preferred.

Examples of commercially available carboxyl group-containing resins without a urethane skeleton include ZFR-1491H and ZCR-1569H (both manufactured by Nippon Kayaku Co., Ltd.).

The content of the carboxyl group-containing resin that does not have a urethane skeleton is preferably 20 to 80% by mass, more preferably 35 to 60% by mass, based on the total mass of the carboxyl group-containing resin in terms of solid content.

[Photocurable compound without carboxyl group]
A photocurable compound that does not have a carboxyl group is a compound that has an ethylenically unsaturated group, and includes photocurable polymers, photocurable oligomers, photocurable monomers, etc., and may be a mixture thereof. . By including a photocurable compound that does not have a carboxyl group, the strength of the cured product can be improved. The photocurable compounds having no carboxyl group can be used alone or in combination of two or more.

Examples of the photocurable oligomer include unsaturated polyester oligomers, (meth)acrylate oligomers, and the like. Examples of (meth)acrylate oligomers include epoxy (meth)acrylates such as phenol novolak epoxy (meth)acrylate, cresol novolac epoxy (meth)acrylate, and bisphenol type epoxy (meth)acrylate, urethane (meth)acrylate, and epoxyurethane (meth)acrylate. ) acrylate, polyester (meth)acrylate, polyether (meth)acrylate, polybutadiene-modified (meth)acrylate, and the like.

Examples of photocurable monomers include alkyl (meth)acrylates such as 2-ethylhexyl (meth)acrylate and cyclohexyl (meth)acrylate; such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate. Hydroxyalkyl (meth)acrylates; mono- or di(meth)acrylates of alkylene oxide derivatives such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol; hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipenta Polyhydric alcohols such as erythritol, trishydroxyethyl isocyanurate, or polyvalent (meth)acrylates of their ethylene oxide or propylene oxide adducts; Phenols such as phenoxyethyl (meth)acrylate, polyethoxydi(meth)acrylate of bisphenol A Examples include (meth)acrylates of ethylene oxide or propylene oxide adducts; (meth)acrylates of glycidyl ethers such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate; and melamine (meth)acrylate. It will be done. One type of photopolymerizable monomer may be used alone, or two or more types may be used in combination.
In addition, as a photocurable compound without a carboxyl group, phenol is a phenol compound having two or more phenolic hydroxyl groups in the molecule, which is obtained by a condensation reaction of a polymethylol form of bisphenol A or bisphenol F with phenols. A photocurable compound obtained by converting some or all of the hydroxyl groups into an oxyalkyl group having an alcoholic hydroxyl group and adding acrylic acid and/or methacrylic acid to the terminal hydroxyl group of the resulting oxyalkyl group. preferable.

Commercially available products include, for example, DPCA-60 manufactured by Nippon Kayaku Co., Ltd.

The content of the photocurable compound having no carboxyl group is preferably 0.1 to 30% by mass based on the total mass of the resin layer in terms of solid content.

[Photopolymerization initiator]
The photopolymerization initiator is used to react a carboxyl group-containing resin and/or a photocurable compound that does not have a carboxyl group by exposure to light. As the photopolymerization initiator, any known ones can be used. The photopolymerization initiators may be used alone or in combination of two or more.

Examples of the photopolymerization initiator include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, and bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide. dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,6-dimethoxy) benzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide Bisacylphosphine oxides such as; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, Monoacylphosphine oxides such as pivaloylphenylphosphinic acid isopropyl ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide; ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate, 1-hydroxy-cyclohexylphenyl ketone , 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2 Hydroxyacetophenones such as -methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzoin, benzyl, benzoin methyl ether , benzoins such as benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether; benzoin alkyl ethers; benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4 , 4'-bisdiethylaminobenzophenone and other benzophenones; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-Methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-(dimethylamino )-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone, acetophenones such as N,N-dimethylaminoacetophenone; thioxanthone, 2-ethylthioxanthone, Thioxanthone such as 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, Anthraquinones such as 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone; Ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; Ethyl-4-dimethylaminobenzoate, 2-(dimethyl Benzoic acid esters such as amino) ethyl benzoate and p-dimethylbenzoic acid ethyl ester; 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyloxime)], ethanone, 1- Oxime esters such as [9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-,1-(O-acetyloxime); bis(η5-2,4-cyclopentadiene-1 -yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1 Titanium such as phenyl disulfide 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, and tetramethylthiuram disulfide.

Commercially available α-aminoacetophenone photopolymerization initiators include Omnirad 907, 369, 369E, and 379 manufactured by IGM Resins. Further, as a commercially available acylphosphine oxide photopolymerization initiator, Omnirad 819 manufactured by IGM Resins, etc. may be mentioned. Commercially available oxime ester photopolymerization initiators include Irgacure OXE01 and OXE02 manufactured by BASF Japan Co., Ltd., N-1919 manufactured by ADEKA Co., Ltd., NCI-831 and NCI-831E manufactured by ADEKA Co., Ltd., and Irgacure NCI-831 and NCI-831E manufactured by Changzhou Strong Electronics New Materials Co., Ltd. Examples include TR-PBG-304. A commercially available titanocene photopolymerization initiator includes Omnirad 784 manufactured by IGM Resins. A commercially available thioxanthone photopolymerization initiator includes KAYACURE DETX-S manufactured by Nippon Kayaku Co., Ltd.

In addition, JP 2004-359639, JP 2005-097141, JP 2005-220097, JP 2006-160634, JP 2008-094770, JP 2008-509967, Examples include carbazole oxime ester compounds described in Japanese Patent Application Publication No. 2009-040762 and JP-A No. 2011-80036.

The content of the photopolymerization initiator is 0.01 to 30% by mass based on the total mass of the resin layer in terms of solid content.

A photoinitiation aid or sensitizer may be used in combination with the photopolymerization initiator described above. Examples of the photoinitiation aid or sensitizer include benzoin compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, tertiary amine compounds, and xanthone compounds. Although these compounds can be used as a photopolymerization initiator in some cases, it is preferable to use them in combination with a photopolymerization initiator. Moreover, one type of photoinitiation aid or sensitizer may be used alone, or two or more types may be used in combination.

[Inorganic filler]
As the inorganic filler, known inorganic fillers can be used. Examples of inorganic fillers include amorphous silica, crystalline silica, Neuburg silica, aluminum hydroxide, glass powder, talc, clay, magnesium carbonate, calcium carbonate, natural mica, synthetic mica, aluminum hydroxide, barium sulfate, Inorganic fillers such as barium titanate, iron oxide, non-fibrous glass, hydrotalcite, mineral wool, aluminum silicate, calcium silicate, and zinc white can be used, and combinations thereof may also be used. The inorganic filler preferably contains at least one of aluminum hydroxide and hydrotalcite.
Commercially available products include, for example, BF013 (aluminum hydroxide) manufactured by Nippon Light Metal Co., Ltd. and IXEPLAS-A1 (hydrotalcite-based ion scavenger) manufactured by Toagosei Co., Ltd.

The content of the inorganic filler is not particularly limited, but from the viewpoint of viscosity, coatability, moldability, etc., it is preferably 0.1 to 50 mass based on the total mass of the resin layer in terms of solid content. %. Note that the filler may be surface-treated with a coupling agent in order to improve dispersibility in the curable resin composition.

[Thermosetting resin]
As the thermosetting resin, any known thermosetting resin can be used. When the resin layer of the laminated structure contains a thermosetting resin, the heat resistance of the cured product can be improved. Examples of thermosetting resins include amino resins such as melamine resins, benzoguanamine resins, melamine derivatives, and benzoguanamine derivatives, isocyanate compounds, blocked isocyanate compounds, cyclocarbonate compounds, epoxy resins, oxetane compounds, episulfide resins, bismaleimide, and carbodiimide resins. It is possible to use known thermosetting resins such as . Particularly preferred are thermosetting resins having a plurality of cyclic ether groups or cyclic thioether groups (hereinafter abbreviated as cyclic (thio)ether groups) in the molecule. The thermosetting resin can be used alone or in combination of two or more.

The above-mentioned thermosetting resin having a plurality of cyclic (thio)ether groups in the molecule is a resin having a plurality of 3-, 4-, or 5-membered cyclic (thio)ether groups in the molecule, for example, Examples include resins having multiple epoxy groups, ie, polyfunctional epoxy resins, compounds having multiple oxetanyl groups in the molecule, ie, polyfunctional oxetane compounds, and resins having multiple thioether groups in the molecule, ie, episulfide resins.

Examples of such epoxy resins include bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, brominated bisphenol A epoxy resin, bisphenol S epoxy resin, phenol novolak epoxy resin, Cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin and the like.

Commercially available epoxy resins include, for example, jER 806, 807, 828, 834, YX8000, YX8034 manufactured by Mitsubishi Chemical Corporation, YD-128, YDF-170, ZX-1059 manufactured by Nippon Steel Chemical & Materials Corporation, ST-3000, EPICLON 830, 835, 840, 850, N-730A, N-695, N-870-75EA, HP-7200L manufactured by DIC Corporation, and RE-306, NC- manufactured by Nippon Kayaku Co., Ltd. Examples include 3000H and NC-3000L.

Examples of polyfunctional oxetane compounds include bis[(3-methyl-3-oxetanylmethoxy)methyl]ether, bis[(3-ethyl-3-oxetanylmethoxy)methyl]ether, and 1,4-bis[(3- Methyl-3-oxetanylmethoxy)methyl]benzene, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, (3-methyl-3-oxetanyl)methyl acrylate, (3-ethyl-3- In addition to polyfunctional oxetanes such as (oxetanyl) methyl acrylate, (3-methyl-3-oxetanyl) methyl methacrylate, (3-ethyl-3-oxetanyl) methyl methacrylate, and their oligomers or copolymers, oxetane alcohol and novolac resins , poly(p-hydroxystyrene), cardo-type bisphenols, calixarenes, calixresorcinarenes, and etherification products with resins having hydroxyl groups such as silsesquioxane. Other examples include copolymers of unsaturated monomers having an oxetane ring and alkyl (meth)acrylates.

Examples of the resin having a plurality of cyclic thioether groups in the molecule include bisphenol A episulfide resin. Furthermore, an episulfide resin in which the oxygen atom of the epoxy group of a novolac type epoxy resin is replaced with a sulfur atom can also be used using a similar synthesis method.

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

As the isocyanate compound, a polyisocyanate compound can be blended. Examples of the polyisocyanate compound include 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,5-diisocyanate, o-xylylene diisocyanate, m-xylylene diisocyanate, and Aromatic polyisocyanates such as 2,4-tolylene dimer; aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, methylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4-methylene bis(cyclohexyl isocyanate) and isophorone diisocyanate; bicyclo Examples include alicyclic polyisocyanates such as heptane triisocyanate; and adducts, biurets, and isocyanurates of the above-mentioned isocyanate compounds.

As the blocked isocyanate compound, an addition reaction product of an isocyanate compound and an isocyanate blocking agent can be used. Examples of the isocyanate compound that can react with the isocyanate blocking agent include the above-mentioned polyisocyanate compounds. Isocyanate blocking agents include, for example, phenolic blocking agents; lactam blocking agents; active methylene blocking agents; alcohol blocking agents; oxime blocking agents; mercaptan blocking agents; acid amide blocking agents; imide blocking agents; Examples include amine blocking agents, imidazole blocking agents, and imine blocking agents.

The content of the thermosetting resin is preferably 1 to 50% by mass based on the total mass of the resin layer in terms of solid content.

[Flame retardants]
As the flame retardant, compounds shown in the following flame retardant embodiments A to C can be used alone or in combination of two or more.
(Aspect A of flame retardant)
As one embodiment of the flame retardant that can be included in the resin layer of the laminated structure, a compound having a hexaphenoxycyclotriphosphazene structure as a basic skeleton can be used.

Compounds in which none of the six phenoxy groups in the structure are substituted can be used.
At least one hydrogen atom (preferably one hydrogen atom) of the six phenoxy groups in the structure is substituted with a cyano group (-CN) or a hydroxyl group (-OH). Compounds can also be used.
For example, only one of the two phenoxy groups bonded to the phosphorus atom in the hexaphenoxycyclotriphosphazene structure is substituted with one cyano group (-CN), and the phenoxy group substituted in this way A compound having 2 or more and 4 or less hexaphenoxycyclotriphosphazene structures as a whole can be used as a flame retardant.

Each of the two phenoxy groups bonded to the phosphorus atom in the hexaphenoxycyclotriphosphazene structure is substituted with one cyano group (-CN), and the thus substituted phenoxy group is replaced with the hexaphenoxycyclotriphosphazene structure. Compounds having all six in total can be used as flame retardants.

Only one of the two phenoxy groups bonded to the phosphorus atom in the hexaphenoxycyclotriphosphazene structure is substituted with one hydroxyl group (-OH), and the thus substituted phenoxy group is Compounds having a total of three phenoxycyclotriphosphazene structures can be used as flame retardants.

Examples of commercially available flame retardants in the flame retardant embodiment A include FP-100, FP-300B, FP-300, and SPH-100 (all manufactured by Fushimi Pharmaceutical Co., Ltd.).

For example, a compound in which none of the six phenoxy groups is substituted and a compound in which the hydrogen atom in at least one of the six phenoxy groups is substituted with a cyano group (-CN) or a hydroxyl group (-OH) When both compounds are used, the ratio of the former compound to the latter compound is preferably 1:0.01 to 1:100, more preferably 1:0.1 to 1:10.

(Aspect B of flame retardant)
Embodiment B of the flame retardant includes a phosphorus-containing compound that does not have a phosphazene structure.

（式中、Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立に、ハロゲン原子以外の置換基を示す。） Examples of phosphorus-containing compounds that do not have a phosphazene structure include those known as organic phosphorus flame retardants that do not have a phosphazene structure, and suitable ones include phosphoric acid esters, condensed phosphoric acid esters, and phosphorus element-containing (meth) ) Reactive phosphorus-containing compounds such as acrylates, phosphorus compounds having a carboxyl group, phosphorus-containing compounds having a phenolic hydroxyl group, and compounds represented by the following chemical formulas.

(In the formula, R ¹ , R ² and R ³ each independently represent a substituent other than a halogen atom.)

Specific examples of the phosphorus element-containing (meth)acrylate include compounds in which R ¹ and R ² in the above general formula (I) are hydrogen atoms, and R ³ is a (meth)acrylate derivative. Generally, it can be synthesized by a Michael addition reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and a known and commonly used polyfunctional (meth)acrylate monomer. Commercially available phosphorus element-containing (meth)acrylates include RAYLOCK1722 (manufactured by Daicel Allnex Corporation).

Preferred flame retardants include, in the above chemical formula, R ¹ and R ² are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ³ is a 2,5-dihydroxyphenyl group or a 3,5-di- Examples include, but are not limited to, t-butyl-4-hydroxyphenyl groups.

を有する難燃剤である。 A particularly preferred flame retardant in flame retardant embodiment B has the following chemical formula:

It is a flame retardant with

Commercial products of the phosphorus-containing compound represented by the above chemical formula include HCA, SANKO-220, M-ESTER, and HCA-HQ (all manufactured by Sanko Co., Ltd.).

Furthermore, phosphorus-containing compounds that are oligomers or polymers having phenolic hydroxyl groups can be used. As the oligomer having a carboxylic acid, a phosphorus element-containing dicarboxylic acid represented by the following general formula (II) or its anhydride can also be used.

Examples of the hydrocarbon group having 1 to 6 carbon atoms represented by R ⁴ and R ⁵ in the above general formula (II) include an alkyl group having 1 to 6 carbon atoms, and an alkenyl group having 1 to 6 carbon atoms. group, cycloalkyl group, and phenyl group. Examples of alkyl groups having 1 to 6 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, pentyl group, isopentyl group, hexyl group, and alkenyl groups having 1 to 6 carbon atoms. Examples include vinyl group, allyl group, 3-butenyl group, isobutenyl group, 4-pentenyl group, and 5-hexenyl group. The hydrocarbon group having 1 to 6 carbon atoms may be branched or substituted.

Examples of the above-mentioned phosphorus element-containing dicarboxylic acid or its anhydride include a compound obtained by reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with itaconic acid and its anhydride. Examples include things.

(Aspect C of flame retardant)
As aspect C of the flame retardant, which is different from aspects A and B, a phosphorus-containing compound having a metal salt such as a phosphinate metal salt can be used. Specific examples of phosphinic acids constituting phosphinic acid metal salts include phosphinic acid, dimethylphosphinic acid, ethylmethylphosphinic acid, diethylphosphinic acid, methyl-n-propylphosphinic acid, methanedi(methylphosphinic acid), benzene-1, 4-(dimethylphosphinic acid), methylphenylphosphinic acid, phenylphosphinic acid, diphenylphosphinic acid and mixtures thereof.

Examples of the metal components constituting the phosphinate include calcium, magnesium, aluminum, zinc, bismuth, manganese, sodium, and potassium. Preferred are calcium, magnesium, aluminum, and zinc.

Commercially available phosphinate metal salts include, for example, EXOLIT OP 930 and EXOLIT OP 935 (both manufactured by Clariant).

The content of the flame retardant (total content of the flame retardant embodiments A to C actually used) is preferably 0.1 to 60% by mass based on the total mass of the resin layer in terms of solid content, More preferably, it is 1 to 30% by mass.

For example, when using the above flame retardant embodiment A and the above flame retardant embodiment B, the mass ratio of flame retardant embodiment A and flame retardant embodiment B is preferably 1:0.01 to 1. :100, more preferably 1:0.01 to 1:30.
For example, when using the above flame retardant embodiment A and the above flame retardant embodiment C, the mass ratio of flame retardant embodiment A and flame retardant embodiment C is preferably 1:0.01 to 1. :100, more preferably 1:0.01 to 1:50.

[Colorant]
A coloring agent can be added to the resin layer of the laminated structure of the present invention. The coloring agent is not particularly limited, and one or a combination of known coloring agents such as red, blue, green, and yellow may be used, and any of pigments, dyes, and dyes may be used; A coloring agent that does not contain halogen is preferable from the viewpoint of reducing the amount of oxidation and having little effect on the human body.

Red coloring agents include monoazo, disazo, azo lake, benzimidazolone, perylene, diketopyrrolopyrrole, condensed azo, anthraquinone, and quinacridone.Specifically, the following colors are used. - Index (C.I.; published by The Society of Dyers and Colorists) numbered.

Examples of monoazo red colorants include Pigment Red 1, 2, 3, 4, 5, 6, 8, 9, 12, 14, 15, 16, 17, 21, 22, 23, 31, 32, 112, 114, 146, 147, 151, 170, 184, 187, 188, 193, 210, 245, 253, 258, 266, 267, 268, 269 and the like. Further, examples of the disazo red coloring agent include Pigment Red 37, 38, and 41. In addition, as monoazo lake red colorants, Pigment Red 48:1, 48:2, 48:3, 48:4, 49:1, 49:2, 50:1, 52:1, 52:2, 53: Examples include 1,53:2, 57:1, 58:4, 63:1, 63:2, 64:1, 68, and the like. Further, examples of the benzimidazolone red colorant include Pigment Red 171, 175, 176, 185, and 208. Examples of perylene-based red colorants include Solvent Red 135, 179, Pigment Red 123, 149, 178, 179, 190, 194, 224, and the like. Further, examples of the diketopyrrolopyrrole red colorant include Pigment Red 254, 255, 264, 270, 272, and the like. Further, examples of condensed azo red colorants include Pigment Red 220, 144, 166, 214, 220, 221, 242, and the like. Further, examples of the anthraquinone red colorant include Pigment Red 168, 177, 216, Solvent Red 149, 150, 52, 207, and the like. In addition, examples of the quinacridone-based red colorant include Pigment Red 122, 202, 206, 207, and 209.

Blue colorants include phthalocyanine and anthraquinone, and pigments include compounds classified as pigments, such as Pigment Blue 15, 15:1, 15:2, 15:3, 15: 4,15:6,16,60. As the dye system, Solvent Blue 35, 63, 68, 70, 83, 87, 94, 97, 122, 136, 67, 70, etc. can be used. In addition to the above, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

Examples of yellow colorants include monoazo, disazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone. For example, anthraquinone yellow colorants include Solvent Yellow 163, Pigment Yellow 24, 108, 193, 147, 199, 202 and the like. Examples of the isoindolinone yellow colorant include Pigment Yellow 110, 109, 139, 179, 185, and the like. Examples of condensed azo yellow colorants include Pigment Yellow 93, 94, 95, 128, 155, 166, and 180. Examples of the benzimidazolone yellow colorant include Pigment Yellow 120, 151, 154, 156, 175, 181, and the like. In addition, as the monoazo yellow colorant, Pigment Yellow 1, 2, 3, 4, 5, 6, 9, 10, 12, 61, 62, 62:1, 65, 73, 74, 75, 97, 100, 104, 105, 111, 116, 167, 168, 169, 182, 183 and the like. In addition, examples of the disazo yellow colorant include Pigment Yellow 12, 13, 14, 16, 17, 55, 63, 81, 83, 87, 126, 127, 152, 170, 172, 174, 176, 188, 198, etc. can be mentioned.

In addition, coloring agents such as purple, orange, brown, and black may be added. Specifically, Pigment Black 1, 6, 7, 8, 9, 10, 11, 12, 13, 18, 20, 25, 26, 28, 29, 30, 31, 32, Pigment Violet 19, 23, 29 , 32, 36, 38, 42, Solvent Violet 13, 36, C. I. Pigment Orange 1, 5, 13, 14, 16, 17, 24, 34, 36, 38, 40, 43, 46, 49, 51, 61, 63, 64, 71, 73, Pigment Brown 23, 25, carbon black, etc. can be mentioned. In addition, a plurality of the above-mentioned colorants may be combined to create a color mixture. For example, a red colorant, a blue colorant, and a yellow colorant may be combined to form an amber colorant.

The content of the colorant is preferably 0.01 to 15% by mass based on the total mass of the resin layer in terms of solid content.

[Thermosetting catalyst]
A thermosetting catalyst can be blended into the resin layer of the laminated structure of the present invention. Examples of the thermosetting catalyst include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- Imidazole derivatives such as (2-cyanoethyl)-2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzyl Examples include amines, amine compounds such as 4-methyl-N,N-dimethylbenzylamine, hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide, and phosphorus compounds such as triphenylphosphine. In addition, commercially available products include, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, and 2P4MHZ (all brand names of imidazole compounds) manufactured by Shikoku Kasei Kogyo Co., Ltd., and U-CAT 3513N (manufactured by San-Apro Co., Ltd.). (trade name of dimethylamine compound), DBU, DBN, U-CAT SA 102 (all bicyclic amidine compounds and salts thereof), and DICY7 (trade name of dicyandiamide) manufactured by Mitsubishi Chemical Corporation.

Furthermore, guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino S-triazine derivatives such as -S-triazine/isocyanuric acid adduct and 2,4-diamino-6-methacryloyloxyethyl-S-triazine/isocyanuric acid adduct can also be used. One type of thermosetting catalyst may be used alone, or two or more types may be used in combination.

The content of the thermosetting catalyst is preferably 0.01 to 30% by mass based on the total mass of the resin layer in terms of solid content.

[Organic solvent]
The curable resin composition for obtaining the resin layer of the laminated structure of the present invention may contain an organic solvent for the purpose of preparing the composition or adjusting the viscosity when coating it on the first film. . Examples of organic solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, and propylene glycol monomethyl ether. , dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, tripropylene glycol monomethyl ether, and other glycol ethers; ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, diethylene glycol monoethyl ether acetate, Esters such as butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, propylene carbonate; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, and solvent naphtha, etc. , well-known and commonly used organic solvents can be used.

The content of the organic solvent is not particularly limited, and can be appropriately set according to the desired viscosity so as to facilitate the preparation of the curable resin composition.

[Other additive ingredients]
The resin layer of the laminated structure of the present invention may further contain substances known in the field of electronic materials, such as polymerization inhibitors, cyanate compounds, elastomers, mercapto compounds, thixoating agents, adhesion promoters, and blocks. Copolymers, chain transfer agents, copper inhibitors, antioxidants, rust inhibitors, finely divided silica, organic bentonite, thickeners (e.g. montmorillonite), silicone-based, fluorine-based, polymer-based antifoaming agents, etc. , a dispersant, and a leveling agent can be blended.
Commercially available dispersants include, for example, DisperBYK145 and BYK-361N (both manufactured by BYK Chemie Japan Co., Ltd.).

[Water absorption rate of cured resin layer after exposure]
The water absorption rate of the cured product of the resin layer after exposure is the water absorption rate of the cured product of the resin layer that has been exposed but has not been developed after exposure or heated after development.
This water absorption rate indicates how much water the cured product of the resin layer absorbs after exposure, and is expressed by the following formula:
Water absorption rate = [[(Weight (g) after immersing the cured product after exposure in water for 24 hours) - (Weight (g) before immersing the cured product after exposure in water)] / (Weight after immersion in water after exposure) Weight (g) of cured product before immersing it in water] x 100
It can be calculated using
A specific method for measuring this water absorption rate is as follows.
First, a 25 μm thick polyethylene terephthalate film (“E5041” manufactured by Toyobo Co., Ltd.) is prepared as a first film. Next, a curable resin composition containing a carboxyl group-containing resin containing a carboxyl group-containing resin having a urethane skeleton, a photocurable compound having no carboxyl group, a photopolymerization initiator, an inorganic filler, and a thermosetting resin is prepared. It is 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. In this way, a laminated structure having the first film and the resin layer is obtained. The obtained laminated structure was cut into a size of 100 mm in width and 80 mm in length, and the resin layer was placed on a glass substrate of 160 mm in width, 110 mm in length, and 1 mm in thickness using a vacuum laminator (Laminator CVP manufactured by Nikko Materials Co., Ltd.). -300) to paste. The lamination temperature is 70°C, the vacuum holding time is 20 seconds, and the pressurization time is 90 seconds. In this way, an evaluation substrate having a resin layer on a glass substrate is produced.
The obtained evaluation substrate was irradiated with light using an exposure device equipped with a metal halide lamp (manufactured by Oak Seisakusho Co., Ltd., HMW-680-GW20) at 20°C and at an optimal exposure dose (400 mJ/cm ² ), and cured after exposure. Obtain an evaluation board having a substance. After the first film is peeled off from the cured product, the weight of the evaluation substrate is measured, and the weight of the glass substrate itself is subtracted to obtain the weight of the cured product, i.e., the weight of the cured product after exposure before being immersed in water. Get weight.
Thereafter, a large amount of pure water (20° C.) in which the cured product is sufficiently immersed is put into a beaker, and the evaluation substrate is immersed therein. After 24 hours, the evaluation substrate is taken out. After removing the water on the surface of the glass substrate and the cured product, measure the weight of the evaluation substrate, subtract the weight of the glass substrate itself, and calculate the weight of the cured product after immersion, that is, the cured product after exposure. Obtain the weight after soaking in water for an hour. The water absorption rate is calculated using the above formula based on the weight of the obtained cured product.

The water absorption rate of the cured product of the resin layer after exposure is determined by the components with high water absorption among the components contained in the resin layer (mainly carboxy-containing resins (for example, in the case of the examples described later, carboxyl group-containing urethane skeletons). It can be determined by considering the water absorption rate of resin) and any flame retardant).
The water absorption rate of the cured resin layer after exposure is 1.0 to 4.0, preferably 1.0 to 3.0.
If the water absorption rate of the cured product of the resin layer after exposure is less than 1.0, for example, as shown in FIG. However, there is a residue of the cured product (reference number 4) after exposure, making it impossible to smooth the surface formed by the top surface of the circuit and the top surface of the cured product of the resin layer. Although this phenomenon is speculative, it is thought that this phenomenon occurs because the cured product of the resin layer after exposure becomes difficult to dissolve in the developer.
If the water absorption rate of the cured resin layer after exposure exceeds 4.0, for example, as shown in FIG. 2(b), the cured resin layer between the circuits will be dented. The surface formed by the upper surface of the circuit and the upper surface of the cured resin layer cannot be smoothed. Although this phenomenon is speculative, it is thought that this phenomenon occurs because the cured product of the resin layer after exposure becomes easily soluble in the developer (that is, overdevelopment occurs).
Note that if the water absorption rate of the cured resin layer after exposure is between 1.0 and 4.0, it is possible to wash off the cured resin layer that covers the edges of the circuit as shown in Figure 1. The surface formed by the upper surface of the circuit and the upper surface of the cured resin layer can be smoothed.

Hereinafter, the present invention will be specifically explained using Examples, but the present invention is not limited to these Examples.

<Preparation of curable resin composition>
Each component was blended in the proportions shown in Table 1 (Examples 1 to 9) and Table 2 (Comparative Examples 1 to 4), and these were stirred with a dissolver (room temperature, rotation speed 500 rpm, 5 minutes). Thereafter, dispersion was performed using zirconia beads (1 mm) using a bead mill for 2 hours, and the curable resin compositions for Examples (Examples 1 to 9) and the curable resin compositions for Comparative Examples (Comparative Examples 1 to 9) were dispersed for 2 hours. 4) was obtained.
<Preparation of laminated structure>
A 25 μm thick polyethylene terephthalate film (“E5041” manufactured by Toyobo Co., Ltd.) was prepared as the first film. The curable 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. In this way, laminated structures of Examples 1 to 9 and Comparative Examples 1 to 4 having the first film and the resin layer were obtained.

<Water absorption rate of cured product after exposure>
Regarding the resin layers of the obtained laminated structures of Examples 1 to 9 and Comparative Examples 1 to 4, the water absorption rates of the cured products after exposure were measured by the following method. The measurement results are shown in Tables 1 and 2.
(Method of measuring water absorption rate)
The laminated structures of Examples 1 to 9 and Comparative Examples 1 to 4 were cut out to a size of 100 mm in width and 80 mm in length, and the resin layer of the obtained laminated structure was placed on a glass substrate (160 mm in length x 110 mm x 1 mm in thickness). A vacuum laminator (Laminator CVP-300 manufactured by Nikko Materials Co., Ltd.) was used to affix the film. The lamination temperature was 70°C, the vacuum holding time was 20 seconds, and the pressurization time was 90 seconds. In this way, an evaluation substrate having a resin layer and a first film on a glass substrate was produced.
The obtained evaluation substrate was irradiated with light at 20°C and at the optimum exposure amount (400 mJ/cm2) using an exposure device equipped with a metal halide lamp (manufactured by Oak Seisakusho Co., Ltd., HMW-680-GW20) to remove the resin after exposure. A cured product of the layer was obtained. After the first film is peeled off from the cured product, the weight of the evaluation substrate is measured, and the weight of the glass substrate itself is subtracted to obtain the weight of the cured product, i.e., the weight of the cured product after exposure before being immersed in water. Got the weight. Thereafter, a large amount of pure water (20° C.) to sufficiently immerse the cured product was placed in a beaker, and the evaluation board was immersed therein. After 24 hours, the evaluation board was taken out. After removing the water on the surface of the glass substrate and cured product, measure the weight of the evaluation substrate, subtract the weight of the glass substrate itself, and calculate the weight of the cured product after immersion, that is, the cured product after exposure for 24 hours. The weight after immersion in water was obtained. The water absorption rate was calculated using the following formula based on the weight of the obtained cured product.
Water absorption rate = [[(Weight (g) after immersing the cured product after exposure in water for 24 hours) - (Weight (g) before immersing the cured product after exposure in water)] / (Weight after immersion in water after exposure) Weight (g) of cured product before immersing it in water] x 100

The obtained laminated structures of Examples 1 to 9 and Comparative Examples 1 to 4 were subjected to the following tests for flame retardancy, cross-sectional smoothness, and insulation reliability. The test results are shown in Tables 1 and 2.

<Flame retardancy>
The resin layer of the laminated structure of each of the above Examples and Comparative Examples was made of polyimide films of 25 μm and 12.5 μm thick (manufactured by DuPont-Toray Co., Ltd., Kapton (registered trademark) 100H (25 μm), Kapton (registered trademark) 50H). (12.5 μm)) using a vacuum laminator (Laminator CVP-300 manufactured by Nikko Materials Co., Ltd.). The lamination temperature was 70°C, the vacuum holding time was 20 seconds, and the pressing time was 90 seconds. The resin layer was exposed on the entire surface of the obtained double-sided substrate at 20°C using an exposure device equipped with a metal halide lamp (HMW-680-GW20, manufactured by Oak Seisakusho Co., Ltd.) at an optimum exposure dose of 400 mJ/cm ^{2 .} % Na ₂ CO ₃ aqueous solution was developed for 60 seconds at a spray pressure of 0.2 MPa, and thermally cured at 150° C. for 60 minutes to obtain an evaluation sample. This sample for flame retardancy evaluation was subjected to a thin material vertical combustion test in accordance with the UL94 standard.
The flame retardancy test was evaluated based on the following criteria.
◎: Achieved VTM-0 with UL94. Extinguishes within 2 seconds on first ignition.
○: Achieved VTM-0 with UL94. Extinguishes in more than 2 seconds but less than 5 seconds after the first ignition.
×: VTM-0 not achieved with UL94.

<Cross-sectional smoothness>
The resin layer of the laminated structure of each of the above examples and comparative examples was coated on a 25 μm thick polyimide film (Kapton (registered trademark) 100H manufactured by DuPont-Toray Co., Ltd.) using a vacuum laminator (laminator CVP- manufactured by Nikko Materials Co., Ltd.). 300). The lamination temperature was 70°C, the vacuum holding time was 20 seconds, and the pressurization time was 90 seconds. The resin layer on the obtained substrate was exposed to light at 20°C using an exposure device equipped with a metal halide lamp (HMW-680-GW20 manufactured by Oak Seisakusho Co., Ltd.) at an optimum exposure dose of 400 mJ/ ^cm2 , and 1 wt% Na was added at 30°C. ₂ CO ₃ aqueous solution was developed for 60 seconds at a spray pressure of 0.2 MPa, and the resin layer was cured by heating at 150° C. for 60 minutes.
The circuit board after thermosetting was sealed with a sealing material "cold embedding resin manufactured by Struers Co., Ltd.", and then a cross section was cut out and observed with an optical microscope.
Cross-sectional smoothness was evaluated using the following criteria.
◎: There is no residue on the circuit, and the circuits are completely smooth. The edges of the circuit are well filled.
○: There is no residue on the circuit, and the area between the circuits is smooth to the extent that it does not interfere with the subsequent process. The edges of the circuit are well filled.
×: There is a residue on the circuit, or the circuits are not smooth. The edges of the circuit are not filled sufficiently.
Note that "residues of cured product present" in Comparative Example 1 is the state shown in FIG. 2(a), and "concavities of cured product present" in Comparative Examples 2 and 3 is the state shown in FIG. 2(b).

<Insulation reliability>
The resin layer of the laminated structure of each of the above examples and comparative examples was placed on a polyimide substrate (Espanex (registered trademark) manufactured by Nippon Steel Chemical & Materials Co., Ltd.) with L/S = 50/50 μm using a vacuum laminator (Nikko). It was pasted using a laminator CVP-300 manufactured by Materials Co., Ltd. The lamination temperature was 70°C, the vacuum holding time was 20 seconds, and the pressurization time was 90 seconds. The resin layer on the obtained substrate was exposed to light at 20°C using an exposure device equipped with a metal halide lamp (HMW-680-GW20 manufactured by Oak Seisakusho Co., Ltd.) at an optimum exposure dose of 400 mJ/ ^cm2 , and 1 wt% Na was added at 30°C. ₂ CO ₃ aqueous solution was developed for 60 seconds at a spray pressure of 0.2 MPa, and cured by heating at 150° C. for 60 minutes. A bias voltage of 50 V DC was applied to the obtained evaluation board, and the temperature was 85° C. and 85% R. H. The resistance value was confirmed by continuous measurement in a constant temperature and humidity chamber (manufactured by ESPEC Co., Ltd., highly accelerated life test device). Insulation reliability was evaluated using the following criteria.
○: No short circuit occurred after 1000 hours.
×: Short circuit occurred within 1000 hours.

＊１：日本化薬株式社製のＺＦＲ－１４９１Ｈ：固形分６２．５質量％、ビスフェノールＦ骨格を有するカルボキシル基含有エポキシアクリレート樹脂（酸価：１００ｍｇＫＯＨ／ｇ、重量平均分子量：１５，０００）
＊２：日本化薬株式社製のＺＣＲ－１５６９Ｈ：固形分７０質量％、ビフェニル骨格を有するカルボキシル基含有エポキシアクリレート樹脂（酸価：１００ｍｇＫＯＨ／ｇ、重量平均分子量：４５，０００）
＊３：日本化薬株式社製のＳＮ－１７２：固形分６０質量％、ウレタン骨格を有するカルボキシル基含有樹脂（酸価：４５ｍｇＫＯＨ／ｇ、重量平均分子量：１０，０００）
＊４：日本化薬株式社製のＵＸＥ－３００２：固形分６５質量％、ウレタン骨格を有するカルボキシル基含有樹脂（酸価：１００ｍｇＫＯＨ／ｇ、重量平均分子量：７，５００）
＊５：日本化薬株式会社製のＫＡＹＡＲＡＤ ＤＰＣＡ－６０、６個のアクリロイル基を有し、カルボキシル基を有しない光硬化性化合物
＊６：ビックケミー・ジャパン株式会社製のＤｉｓｐｅｒＢＹＫ１４５
＊７：ビックケミー・ジャパン株式会社製のＢＹＫ－３６１Ｎ
＊８：日産化学株式会社製のメラミン
＊９：日本軽金属株式会社製のＢＦ０１３：水酸化アルミニウム
＊１０：東亜合成株式会社製のＩＸＥＰＬＡＳ－Ａ１：ハイドロタルサイト系のイオン捕捉剤
＊１１：日本化薬株式会社製のＮＣ－３０００Ｌ－ＣＡ７５：固形分７５質量％、ビフェニルアラルキル型エポキシ樹脂
＊１２：三菱ケミカル株式会社製のｊＥＲ８２８：ビスフェノールＡ型エポキシ樹脂
＊１３：２，４，６－トリメチルベンゾイルジフェニルホスフィンオキサイド
＊１４：日本化薬株式社製のＫＡＹＡＣＵＲＥ ＤＥＴＸ－Ｓ、チオキサントン系光重合開始剤
＊１５：ＩＧＭ Ｒｅｓｉｎｓ社製のＯｍｎｉｒａｄ ７８４、チタノセン系光重合開始剤
＊１６：ダイセル・オルネクス株式会社製のＲＡＹＬＯＫ１７２２、難燃剤の態様Ｂ、リン元素含有アクリレート
＊１７：伏見製薬株式会社製のＦＰ－１００、難燃剤の態様Ａ、ヘキサフェノキシシクロトリホスファゼン構造を有する化合物
＊１８：伏見製薬株式会社製のＦＰ－３００Ｂ、難燃剤の態様Ａ、ヘキサフェノキシシクロトリホスファゼン構造を有し、その構造を構成するフェノキシ基における水素原子がシアノ基に置換されている化合物
＊１９：三光株式会社製のＨＣＡ－ＨＱ、難燃剤の態様Ｂ
＊２０：クラリアント社製のＥＸＯＬＩＴ ＯＰ ９３５、難燃剤の態様Ｃ、ホスフィン酸金属塩
＊２１：アンバー系着色剤（Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ １４７：Ｐｉｇｍｅｎｔ Ｒｅｄ １４９：フタロシアニンブルー＝７．５：２．５：１の混合物）
＊２２：ＤＩＣ株式会社製のＰｉｇｍｅｎｔ Ｂｌｕｅ １５：３
＊２３：ＤＩＣ株式会社製のＰｉｇｍｅｎｔ Ｙｅｌｌｏｗ １４７
＊２４：三菱ケミカル株式会社製のカーボンブラック Table 1: Examples

*1: ZFR-1491H manufactured by Nippon Kayaku Co., Ltd.: solid content 62.5% by mass, carboxyl group-containing epoxy acrylate resin having a bisphenol F skeleton (acid value: 100 mgKOH/g, weight average molecular weight: 15,000)
*2: ZCR-1569H manufactured by Nippon Kayaku Co., Ltd.: solid content 70% by mass, carboxyl group-containing epoxy acrylate resin having a biphenyl skeleton (acid value: 100 mgKOH/g, weight average molecular weight: 45,000)
*3: SN-172 manufactured by Nippon Kayaku Co., Ltd.: Solid content 60% by mass, carboxyl group-containing resin with urethane skeleton (acid value: 45 mgKOH/g, weight average molecular weight: 10,000)
*4: UXE-3002 manufactured by Nippon Kayaku Co., Ltd.: Solid content 65% by mass, carboxyl group-containing resin with urethane skeleton (acid value: 100 mgKOH/g, weight average molecular weight: 7,500)
*5: KAYARAD DPCA-60 manufactured by Nippon Kayaku Co., Ltd., a photocurable compound having 6 acryloyl groups and no carboxyl group *6: DisperBYK145 manufactured by BYK Chemie Japan Co., Ltd.
*7: BYK-361N manufactured by BYK Chemie Japan Co., Ltd.
*8: Melamine manufactured by Nissan Chemical Co., Ltd. *9: BF013 manufactured by Nippon Light Metal Co., Ltd.: Aluminum hydroxide *10: IXEPLAS-A1 manufactured by Toagosei Co., Ltd.: Hydrotalcite-based ion scavenger *11: Nipponka NC-3000L-CA75 manufactured by Yakuza Co., Ltd.: Solid content 75% by mass, biphenylaralkyl type epoxy resin *12: jER828 manufactured by Mitsubishi Chemical Corporation: Bisphenol A type epoxy resin *13: 2,4,6-trimethylbenzoyldiphenyl Phosphine oxide *14: KAYACURE DETX-S manufactured by Nippon Kayaku Co., Ltd., thioxanthone-based photoinitiator *15: Omnirad 784 manufactured by IGM Resins, titanocene-based photoinitiator *16: manufactured by Daicel Allnex Co., Ltd. RAYLOK1722, flame retardant aspect B, phosphorus element-containing acrylate *17: FP-100 manufactured by Fushimi Pharmaceutical Co., Ltd., flame retardant aspect A, compound having a hexaphenoxycyclotriphosphazene structure *18: FP manufactured by Fushimi Pharmaceutical Co., Ltd. -300B, flame retardant embodiment A, a compound having a hexaphenoxycyclotriphosphazene structure, in which the hydrogen atom in the phenoxy group constituting the structure is substituted with a cyano group *19: HCA-HQ manufactured by Sanko Co., Ltd. Aspect B of flame retardant
*20: EXOLIT OP 935 manufactured by Clariant, flame retardant embodiment C, phosphinate metal salt *21: Amber colorant (Pigment Yellow 147: Pigment Red 149: Phthalocyanine Blue = 7.5:2.5:1) blend)
*22: Pigment Blue 15:3 manufactured by DIC Corporation
*23: Pigment Yellow 147 manufactured by DIC Corporation
*24: Carbon black manufactured by Mitsubishi Chemical Corporation

上記表２における＊１～＊２４の化合物に関する情報は、表１における＊１～＊２４の化合物に関する情報と同様である。 Table 2: Comparative example

The information regarding the compounds *1 to *24 in Table 2 above is the same as the information regarding the compounds *1 to *24 in Table 1.

1... Substrate; 2... Circuit; 3... Cured product of resin layer; 4... Residue of cured product after exposure; 10... Circuit board

Claims (3)

preparing a laminated structure having a resin layer containing a carboxyl group-containing resin, a photocurable compound having no carboxyl group, a photopolymerization initiator, an inorganic filler, and a thermosetting resin;
Laminating the resin layer of the laminated structure on a circuit board;
a step of exposing the resin layer laminated on the circuit board to produce a cured product of the resin layer;
Developing a circuit board having a cured product of the resin layer after exposure;
heating the circuit board having the cured resin layer after development;
A method for manufacturing a circuit board, the method comprising:
The carboxyl group-containing resin includes a carboxyl group-containing resin having a urethane skeleton, and the water absorption rate of the cured resin layer after exposure is 1.0 to 4.0. Method of manufacturing circuit boards. The carboxyl group-containing resin having a urethane skeleton has a carboxyl group-containing resin having an acid value of 20 to 70 mgKOH/g, and/or a urethane skeleton having an acid value of 80 to 150 mgKOH/g. The method for manufacturing a circuit board according to claim 1, comprising a carboxyl group-containing resin having a carboxyl group-containing resin. The method for manufacturing a circuit board according to claim 1 or 2, wherein the resin layer of the laminated structure contains a flame retardant.

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