Resin composition, prepreg, resin-coated film, resin-coated metal foil, metal-clad laminate, and printed wiring board

Abstract

The present disclosure addresses the problem of providing a resin composition, a cured product of which has a high glass transition temperature and good desmear resistance, wherein a solder resist formed on a printed wiring board including the cured product has good small-diameter opening properties. This resin composition contains a thermosetting resin (A), a coumarin compound (B), and an inorganic filler (C). The thermosetting resin (A) contains an epoxy resin (A1) and a maleimide resin (A2). The content of the maleimide resin (A2) is 8-60 mass% with respect to the total amount of the thermosetting resin (A).

Description

Resin composition, prepreg, resin-coated film, resin-coated metal foil, metal-clad laminate, and printed wiring board

[0001] The present disclosure generally relates to a resin composition, a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a printed wiring board, and more particularly to a resin composition, a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a printed wiring board that contain an epoxy resin.

[0002] Printed wiring boards are widely used in various fields, such as electronic devices, communication devices, and computers. In recent years, small devices, particularly recording media, mobile communication terminals, and notebook PCs, have rapidly become more multifunctional, higher-performance, thinner, and smaller. Accordingly, printed wiring boards used in these products are also required to have finer conductor wiring, higher density, more multi-layered conductor wiring layers, thinner, and higher performance in terms of mechanical properties.

[0003] Patent Document 1 discloses a resin composition as a material for such printed wiring boards. This resin composition contains an epoxy compound, a maleimide compound having an N-phenylmaleimide structure, a phenol compound, a core-shell rubber, and an inorganic filler. The content of the maleimide compound is within a range of 10 parts by mass or more and less than 40 parts by mass per 100 parts by mass of the total of the epoxy compound, maleimide compound, and phenol compound.

[0004] However, although the cured product of the resin composition described in Patent Document 1 has a high glass transition temperature and good desmear resistance, it is prone to reflecting light rays in the 365 nm to 405 nm wavelength range, which is the main wavelength range of metal halide lamps and UV LED light sources used to cure common UV-curable resins. That is, light rays in this wavelength range are reflected and scattered on the surface of the cured product. Therefore, in a solder resist formed on a printed wiring board having an insulating layer containing the cured product, undesired reactions occur due to the reflection and scattering of light rays in this wavelength range on the surface of the insulating layer. That is, the reaction of the solder resist due to exposure to light in this wavelength range cannot be controlled. As a result, when a solder resist is formed on a printed wiring board manufactured using the resin composition and openings are formed by exposing and developing the solder resist to light in this wavelength range, the smaller the inner diameter of the opening, the more likely the shape of the opening will be poor. That is, there may be a problem of poor small-diameter opening properties.

[0005] International Publication No. 2020 / 121734

[0006] An object of the present disclosure is to provide a resin composition, a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a printed wiring board, which have a high glass transition temperature and good desmear resistance when cured, and which provide a solder resist with good small-diameter opening properties when formed on a printed wiring board containing the cured product.

[0007] A resin composition according to one embodiment of the present disclosure includes a thermosetting resin (A), a coumarin compound (B), and an inorganic filler (C). The thermosetting resin (A) includes an epoxy resin (A1) and a maleimide resin (A2). The content of the maleimide resin (A2) is 8% by mass or more and 60% by mass or less, based on the total amount of the thermosetting resin (A).

[0008] A prepreg according to one aspect of the present disclosure includes at least one of the resin composition and a semi-cured product of the resin composition, and a fibrous base material.

[0009] A resin-coated film according to one embodiment of the present disclosure comprises a resin layer containing at least one of the resin composition and a semi-cured product of the resin composition, and a support film.

[0010] A resin-coated metal foil according to one embodiment of the present disclosure includes a resin layer containing at least one of the resin composition and a semi-cured product of the resin composition, and a metal foil.

[0011] A metal-clad laminate according to one embodiment of the present disclosure includes an insulating layer containing a cured product of the resin composition, and a metal layer.

[0012] A metal-clad laminate according to one embodiment of the present disclosure includes an insulating layer containing a cured product of the prepreg, and a metal layer.

[0013] A printed wiring board according to one embodiment of the present disclosure includes an insulating layer containing a cured product of the resin composition, and conductor wiring.

[0014] A printed wiring board according to one aspect of the present disclosure includes an insulating layer containing a cured product of the prepreg, and conductor wiring.

[0015] FIG. 1 is a schematic cross-sectional view showing a prepreg according to an embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view of a resin-coated film (without a cover film) according to an embodiment of the present disclosure. FIG. 3 is a schematic cross-sectional view of the resin-coated film (with a cover film) according to the same embodiment. FIG. 4 is a schematic cross-sectional view of a resin-coated metal foil according to an embodiment of the present disclosure. FIG. 5 is a schematic cross-sectional view of a metal-clad laminate according to an embodiment of the present disclosure. FIG. 6 is a schematic cross-sectional view of a printed wiring board according to an embodiment of the present disclosure. FIG. 7 is a schematic view showing the results of evaluation S or A in the small hole opening property evaluation criteria according to an example of the present disclosure. FIG. 8 is a schematic view showing an example of the results of evaluation B in the small hole opening property evaluation criteria according to an example of the present disclosure. FIG. 9 is a schematic view showing an example of the results of evaluation B in the small hole opening property evaluation criteria according to an example of the present disclosure.

[0016] 1. Overview The resin composition according to this embodiment contains a thermosetting resin (A), a coumarin compound (B), and an inorganic filler (C). The thermosetting resin (A) contains an epoxy resin (A1) and a maleimide resin (A2). The content of the maleimide resin (A2) is 8% by mass or more and 60% by mass or less, based on the total amount of the thermosetting resin (A).

[0017] As described above, when the resin composition contains the above components, the glass transition temperature (Tg) of the cured product of the resin composition increases.

[0018] Furthermore, when the resin composition contains the above-mentioned components, the cured product of the resin composition has good desmear resistance. When the cured product of the resin composition has good desmear resistance, deformation of the processed portion of the printed wiring board 5 produced using the resin composition or peeling of the metal foil can be suppressed, and therefore a decrease in the conductor reliability of the printed wiring board 5 produced using the resin composition can be suppressed.

[0019] Furthermore, by containing the above-mentioned components in the resin composition, the small-diameter opening property of the solder resist (SR) 8 formed on the printed wiring board 5 manufactured using the resin composition can be improved (see FIG. 7). That is, the reflectance of the cured product of the resin composition can be reduced to 20% or less for light with a wavelength of 365 nm or more and 405 nm or less, thereby improving the small-diameter opening property of the solder resist 8 formed on the printed wiring board 5 manufactured using the resin composition. Specifically, first, a solder resist 8 is formed on the printed wiring board 5 manufactured using the resin composition. The formed solder resist 8 is exposed to irradiation light in the wavelength range of 365 nm or more and 405 nm or less through a photomask, causing desired portions of the solder resist 8 to react. Here, the insulating layer 50 of the printed wiring board 5 manufactured using this resin composition can suppress reflection and scattering of the irradiation light in that wavelength range that reaches its surface. Therefore, reaction of undesired portions of the solder resist 8 formed on the printed wiring board 5 can be suppressed or prevented. The solder resist 8 can then be formed into the desired shape using a developer. That is, the solder resist 8 having good small diameter opening properties means that the solder resist 8 can be removed more precisely and accurately. In other words, use of this resin composition in the production of the printed wiring board 5 can contribute to making the conductor wiring 51 on the printed wiring board 5 finer and denser.

[0020] The solder resist 8 may have a known composition and may contain, for example, epoxy resin, polyimide resin, polyphenylene ether resin, aromatic polyene resin, etc. A solder resist that reacts with the light irradiated portion and does not dissolve in the developer is called a negative type solder resist, while a solder resist that reacts with the light irradiated portion and dissolves in the developer is called a positive type solder resist.

[0021] In the present disclosure, the term "small diameter opening" means that the openings 7 formed by exposing the solder resist 8 to irradiation light in the wavelength range and developing the exposed openings 7 have a good shape. The term "small diameter" refers to a substantially circular shape with a diameter of 100 μm or less.

[0022] That is, according to the present embodiment, it is possible to obtain a resin composition, prepreg 1, resin-coated film 2, resin-coated metal foil 3, metal-clad laminate 4, and printed wiring board 5, in which the cured product of the resin composition has a high glass transition temperature and good desmear resistance, and in which the solder resist 8 formed on the printed wiring board 5 manufactured using the resin composition has good small-diameter opening properties. It is believed that using at least one of the resin composition, prepreg 1, resin-coated film 2, resin-coated metal foil 3, and metal-clad laminate 4 in the manufacture of the printed wiring board 5 is effective in miniaturizing and densifying the conductor wiring 51 on the surface of the printed wiring board 5.

[0023] 2. Details (1) Resin Composition The resin composition according to this embodiment is used, for example, as a material for the prepreg 1, the resin-coated film 2, the resin-coated metal foil 3, the metal-clad laminate 4, the printed wiring board 5, and the like.

[0024] The resin composition contains a thermosetting resin (A), a coumarin compound (B), and an inorganic filler (C). Therefore, the resin composition can be thermosetting. The thermosetting resin (A) contains an epoxy resin (A1) and a maleimide resin (A2).

[0025] The glass transition temperature of the cured product of the resin composition is 200°C or higher. In this case, the cured product of the resin composition has a high glass transition temperature and can have excellent heat resistance. The glass transition temperature is preferably 210°C or higher, more preferably 220°C or higher. The upper limit of the glass transition temperature is, for example, 400°C or lower, but is not particularly limited.

[0026] The resin composition is prepared, for example, as follows: A thermosetting resin (A) containing an epoxy resin (A1) and a maleimide resin (A2), a coumarin compound (B), and an inorganic filler (C) are blended and diluted with an appropriate solvent, and the mixture is stirred and mixed to be homogenized.

[0027] The components of the resin composition will be described below. In this disclosure, parts by mass and % by mass refer to the mass of each component only, and do not include the mass of the solvent.

[0028] (1.1) Constituents of Resin Composition <Thermosetting Resin (A)> As described above, the resin composition contains the thermosetting resin (A). The thermosetting resin (A) contains a thermosetting compound. When the thermosetting compound is heated, a polymerization reaction occurs, causing molecular chains to crosslink with each other, forming a three-dimensional polymer network structure, and then curing.

[0029] The thermosetting resin (A) includes an epoxy resin (A1) and a maleimide resin (A2). The thermosetting resin (A) may also include a thermosetting compound other than the epoxy resin (A1) and the maleimide resin (A2). A specific example of such a thermosetting compound is a phenolic resin (A3). Furthermore, the thermosetting resin (A) may further include a thermosetting compound other than the epoxy resin (A1), the maleimide resin (A2), and the phenolic resin (A3). Examples of such a thermosetting compound include, but are not limited to, benzoxazine resins, polyphenylene ether resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, silicone resins, polyurethane resins, polyimide resins, acrylic resins, and methacrylic resins. The thermosetting resin (A) contained in the resin composition may be one type or two or more types.

[0030] <Epoxy Resin (A1)> As described above, the thermosetting resin (A) contains the epoxy resin (A1). The epoxy resin (A1) is a component that can increase the glass transition temperature, adhesion to metals, glass, etc., heat resistance, electrical insulation, flame retardancy, etc. of a cured product of the resin composition.

[0031] The epoxy resin (A1) is a compound having one or more epoxy groups in one molecule. The epoxy resin (A1) may be solid or liquid at 25°C.

[0032] Examples of the epoxy resin (A1) include, but are not limited to, bisphenol-type epoxy resins, novolac-type epoxy resins, biphenyl-type epoxy resins, xylylene-type epoxy resins, aryl alkylene-type epoxy resins, naphthalene-type epoxy resins, naphthalene-skeleton-modified epoxy resins, triphenylmethane-type epoxy resins, anthracene-type epoxy resins, dicyclopentadiene-type epoxy resins, norbornene-type epoxy resins, fluorene-type epoxy resins, stilbene-type epoxy resins, and phosphorus-containing epoxy resins obtained by introducing phosphorus atoms into the above epoxy resins. The epoxy resin (A1) contained in the thermosetting resin (A) may be one type or two or more types.

[0033] Examples of bisphenol type epoxy resins include, but are not limited to, bisphenol A type epoxy resins, bisphenol F type epoxy resins, and bisphenol S type epoxy resins.

[0034] Examples of novolac epoxy resins include, but are not limited to, phenol novolac epoxy resins and cresol novolac epoxy resins.

[0035] Examples of aryl alkylene type epoxy resins include, but are not limited to, phenol aralkyl type epoxy resins, biphenyl aralkyl type epoxy resins, biphenyl novolac type epoxy resins, biphenyl dimethylene type epoxy resins, trisphenol methane novolac type epoxy resins, and tetramethyl biphenyl type epoxy resins.

[0036] Examples of naphthalene skeleton-modified epoxy resins include, but are not limited to, naphthalene skeleton-modified cresol novolac epoxy resins, naphthalene diol aralkyl epoxy resins, naphthol aralkyl epoxy resins, methoxynaphthalene-modified cresol novolac epoxy resins, and methoxynaphthalene dimethylene epoxy resins.

[0037] The epoxy resin (A1) is not necessarily classified into only one type. For example, a biphenyl aralkyl epoxy resin is classified not only as an aryl alkylene epoxy resin but also as a biphenyl epoxy resin.

[0038] The epoxy resin (A1) preferably contains at least one selected from the group consisting of biphenyl-type epoxy resins, naphthalene-type epoxy resins, and dicyclopentadiene-type epoxy resins. In this case, the glass transition temperature, heat resistance, and flame retardancy of the cured product of the resin composition can be improved. Furthermore, the biphenyl-type epoxy resin more preferably contains at least one of a biphenyl novolac-type epoxy resin and a biphenyl aralkyl-type epoxy resin.

[0039] The content of the epoxy resin (A1) is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, based on the total amount of the thermosetting resin (A). In this case, the glass transition temperature, adhesion to metals, glass, etc., heat resistance, flame retardancy, and electrical insulation of the cured product of the resin composition can be improved. Furthermore, the content of the epoxy resin (A1) is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less, based on the total amount of the thermosetting resin (A). In this case, deterioration of adhesion to metals, glass, etc. and electrical insulation can be suppressed.

[0040] The epoxy equivalent of the epoxy resin (A1) is preferably 100 g / eq. or more, more preferably 150 g / eq. or more. The epoxy equivalent of the epoxy resin (A1) is preferably 350 g / eq. or less, more preferably 300 g / eq. or less.

[0041] <Maleimide Resin (A2)> As described above, the thermosetting resin (A) contains the maleimide resin (A2). The maleimide resin (A2) is a component that can increase the glass transition temperature, heat resistance, and desmear resistance of a cured product of the resin composition.

[0042] The maleimide resin (A2) is a compound capable of reacting with the epoxy resin (A1). The maleimide resin (A2) has one or more maleimide groups in one molecule. The maleimide resin (A2) may be solid or liquid at 25°C.

[0043] The maleimide resin (A2) may contain only a single compound, or may contain two or more compounds. Examples of the maleimide resin (A2) include, but are not limited to, monofunctional maleimide resins having one maleimide group in the molecule and polyfunctional maleimide resins having two or more maleimide groups. The maleimide resin (A2) contained in the thermosetting resin (A) may be one type or two or more types.

[0044] Examples of monofunctional maleimide resins having one maleimide group in the molecule include, but are not particularly limited to, chlorophenylmaleimides such as o-chlorophenylmaleimide, methylphenylmaleimides such as o-methylphenylmaleimide, hydroxyphenylmaleimides such as p-hydroxyphenylmaleimide, carboxyphenylmaleimides such as p-carboxyphenylmaleimide, N-dodecylmaleimide, and phenylmethanemaleimide.

[0045] Examples of polyfunctional maleimide resins having two or more maleimide groups in the molecule include, but are not limited to, 4,4'-diphenylmethane bismaleimide, bisphenol A bis(4-maleimidophenyl ether), 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 1,6-bismaleimide-(2,2,4-trimethyl)hexane, 4,4'-diphenylether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, polyphenylmethane maleimide, and polyphenylmethane maleimide.

[0046] The maleimide resin (A2) preferably contains at least polyphenylmethane maleimide, which can increase the glass transition temperature and heat resistance of the cured product of the resin composition.

[0047] The content of the maleimide resin (A2) is 8% by mass or more, preferably 15% by mass or more, and more preferably 25% by mass or more, based on the total amount of the thermosetting resin (A). In this case, the glass transition temperature of the cured product of the resin composition can be increased. Furthermore, the content of the maleimide resin (A2) is 60% by mass or less, preferably 55% by mass or less, and more preferably 45% by mass or less, based on the total amount of the thermosetting resin (A). In this case, the decrease in desmear resistance of the cured product of the resin composition can be suppressed.

[0048] The mass ratio of the epoxy resin (A1) to the maleimide resin (A2) is preferably 10:1 to 2:5, more preferably 5:1 to 1:2, and even more preferably 3:2 to 2:3. In this case, the glass transition temperature and heat resistance of the cured product of the resin composition can be increased, and a decrease in desmear resistance can be suppressed.

[0049] <<Phenol Resin (A3)>> The thermosetting resin (A) may contain a phenol resin (A3). The phenol resin (A3) is a component that can increase the glass transition temperature, heat resistance, and the like of a cured product of the resin composition.

[0050] The phenolic resin (A3) can react with the epoxy resin (A1) and the maleimide resin (A2). The phenolic resin (A3) has a phenolic hydroxyl group in the molecule. The phenolic resin (A3) may be solid or liquid at 25°C.

[0051] Examples of the phenolic resin (A3) include, but are not limited to, biphenylaralkyl phenolic resins, phenylaralkyl phenolic resins, novolac phenolic resins, cresol novolac phenolic resins, bisphenol A novolac phenolic resins, naphthalene phenolic resins, tetrakisphenol phenolic resins, and phosphorus-containing phenolic resins obtained by introducing phosphorus atoms into the above phenolic resins. The phenolic resin (A3) contained in the thermosetting resin (A) may be one type or two or more types.

[0052] The phenolic resin (A3) preferably contains at least one of a naphthalene-type phenolic resin and a biphenyl-type phenolic resin, which can increase the glass transition temperature and heat resistance of the cured product of the resin composition.

[0053] The content of the phenolic resin (A3) is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, based on the total amount of the thermosetting resin (A). In this case, the glass transition temperature and heat resistance of the cured product of the resin composition can be increased. Furthermore, the content of the phenolic resin (A3) is preferably 65% ​​by mass or less, more preferably 55% by mass or less, and even more preferably 45% by mass or less, based on the total amount of the thermosetting resin (A). In this case, a decrease in the brittleness of the cured product of the resin composition can be suppressed.

[0054] The phenolic hydroxyl group equivalent of the phenolic resin (A3) is preferably 100 g / eq. or more, more preferably 120 g / eq. or more. The phenolic hydroxyl group equivalent of the phenolic resin (A3) is preferably 650 g / eq. or less, more preferably 600 g / eq. or less.

[0055] When the thermosetting resin (A) contains the phenolic resin (A3), the mass ratio of the epoxy resin (A1) to the phenolic resin (A3) is preferably 5:1 to 1:2, more preferably 5:2 to 2:3. In this case, the glass transition temperature and heat resistance of the cured product of the resin composition can be increased.

[0056] <Coumarin Compound (B)> As described above, the resin composition contains the coumarin compound (B). The coumarin compound (B) has a coumarin skeleton. The coumarin skeleton is an aromatic compound in which a lactone ring and an aromatic ring are condensed. The coumarin compound (B) has good absorbance for irradiation light in the above wavelength range, and therefore can reduce the reflectance of a cured product of the resin composition for light with a wavelength of 365 nm or more and 405 nm or less.

[0057] The coumarin compound (B) preferably contains a coumarin compound (B1) represented by at least one of the following formulas (1) and (2):

[0058]

[0059]

[0060] In formula (1) and formula (2), R1 and R2 each independently represent a hydrogen atom, an alkyl group, an aryl group, or a hydroxyalkyl group. R3, R4, and R5 each independently represent a hydrogen atom, an alkyl group, or an aryl group. The number of carbon atoms in the alkyl group and hydroxyalkyl group is not particularly limited. The alkyl group and hydroxyalkyl group may be linear or branched, and the number of carbon atoms is, for example, 8 or less, but is not particularly limited. R1 to R5 may bond to other substituents to form a ring structure.

[0061] Examples of the coumarin compound (B1) include, but are not limited to, coumarin, 4-methylcoumarin, 7-amino-4-methylcoumarin, etc. The coumarin compound (B1) contained in the resin composition may be one type or two or more types.

[0062] The absorbance and absorption wavelength of the coumarin compound (B) can be changed by introducing a substituent. For example, by introducing an electron-donating group at the 7-position of the coumarin compound (B), an electron-donating group and an electron-withdrawing group coexist in the molecule of the coumarin compound (B), and charge transfer occurs within the molecule, resulting in higher absorbance.

[0063] The absorbance of the coumarin compound (B) depends on the number of molecules, and the greater the number of molecules, that is, the greater the number of moles of molecules, the greater the absorbance that can be exhibited.

[0064] The content of the coumarin compound (B) is preferably 0.1% by mass or more, more preferably 1.5% by mass or more, and even more preferably 2.0% by mass or more, based on the total amount of the thermosetting resin (A) and the coumarin compound (B). In this case, the reflectance of the cured product of the resin composition can be reduced at wavelengths of 365 nm to 405 nm. Furthermore, the content of the coumarin compound (B) is preferably 10% by mass or less, more preferably 9% by mass or less, and even more preferably 8% by mass or less, based on the total amount of the thermosetting resin (A) and the coumarin compound (B). In this case, a decrease in the glass transition temperature of the cured product of the resin composition can be suppressed.

[0065] <Inorganic Filler (C)> As described above, the resin composition contains the inorganic filler (C), which can reduce the coefficient of thermal expansion of a cured product of the resin composition.

[0066] Examples of the inorganic filler (C) include, but are not limited to, silica such as fused silica or crystalline silica, talc, boehmite, magnesium hydroxide, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, clay, mica, etc. The inorganic filler (C) contained in the resin composition may be one type or two or more types.

[0067] The inorganic filler (C) preferably contains at least one filler selected from the group consisting of silica, talc, boehmite, magnesium hydroxide, and aluminum hydroxide, which can reduce the coefficient of thermal expansion of the cured resin composition.

[0068] The inorganic filler (C) may be surface-treated to improve affinity with the thermosetting resin (A) and prevent aggregation. Examples of the surface treatment include, but are not limited to, aminosilane treatment, mercaptosilane treatment, and alkoxysilane treatment.

[0069] The inorganic filler (C) preferably has an average particle size (D50) of 0.1 μm or more. The inorganic filler (C) preferably has an average particle size of 10 μm or less. In the present disclosure, the term "average particle size" refers to the particle size at 50% of the cumulative total in a volume-based particle size distribution determined by a laser diffraction / scattering method.

[0070] The content of the inorganic filler (C) is preferably 50 parts by mass or more, more preferably 75 parts by mass or more, per 100 parts by mass of the total of the thermosetting resin (A) and the coumarin compound (B). In this case, the thermal expansion coefficient of the cured product of the resin composition can be reduced. Furthermore, the content of the inorganic filler (C) is preferably 300 parts by mass or less, more preferably 250 parts by mass or less, per 100 parts by mass of the total of the thermosetting resin (A) and the coumarin compound (B). In this case, a decrease in adhesion and a decrease in crack resistance of the cured product of the resin composition can be suppressed.

[0071] <Amine Compound (D)> The resin composition may contain an amine compound (D) that does not have a coumarin skeleton. Therefore, the amine compound (D) is a compound different from the coumarin compound (B1) represented by formula (2). The amine compound (D) acts as a curing agent or curing accelerator for the crosslinking (curing) reaction of the thermosetting resin (A), and plays a role in assisting the crosslinking reaction.

[0072] Examples of the amine compound (D) include aromatic amine compounds and fatty acid amine compounds.

[0073] Examples of the aromatic amine compound include, but are not limited to, imidazole compounds such as 2-methylimidazole and 2-ethyl-4-methylimidazole. The aromatic amine compound preferably contains an imidazole compound.

[0074] Examples of the aliphatic amine compound include, but are not limited to, alicyclic amine compounds such as dicyandiamide (DICY), diazabicycloundecene (DBU), and isophoronediamine (IPDA), and chain aliphatic amine compounds such as diethylenetriamine (DTA) and triethylenetriamine (TTA). The aliphatic amine compound preferably contains dicyandiamide.

[0075] The resin composition may contain one or more types of amine compound (D).

[0076] The content of the amine compound (D) is preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and even more preferably 0.05 parts by mass or more, per 100 parts by mass of the total of the thermosetting resin (A) and the coumarin compound (B). The content of the amine compound (D) is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 7 parts by mass or less, per 100 parts by mass of the total of the thermosetting resin (A) and the coumarin compound (B).

[0077] <Core-shell rubber (E)> The resin composition may contain a core-shell rubber (E). The core-shell rubber (E) can increase the glass transition temperature, heat resistance, flame retardancy, impact resistance, etc., and suppress a decrease in the thermal expansion coefficient, desmear resistance, etc. The core-shell rubber (E) is composed of a core which is a filler-like rubber and a shell which is a graft layer and covers the core.

[0078] The core preferably contains at least one selected from the group consisting of a (meth)acrylic acid polymer, a (meth)acrylic acid ester polymer, an olefin compound polymer, polybutadiene, and silicone. The shell preferably contains at least one selected from the group consisting of a styrene-acrylonitrile copolymer, a (meth)acrylic acid polymer, polybutadiene, and silicone. An example of such a core-shell rubber (E) is a silicone-acrylic composite rubber. In the silicone-acrylic composite rubber, the core is a silicone / acrylic polymer and the shell is a styrene-acrylonitrile copolymer. In this disclosure, "(meth)acrylic acid" means at least one of acrylic acid and methacrylic acid. The core-shell rubber (E) contained in the resin composition may be one type or two or more types.

[0079] Commercially available core-shell rubbers (E) can be used. Examples of such commercially available products include those manufactured by Mitsubishi Chemical Corporation under the trade names "S-2001," "S-2006," "S-2501," "S-2030," "S-2100," "S-2130," "S-2200," "SRK200A," "SX-006," and "SX-005"; those manufactured by Aica Kogyo Co., Ltd. under the trade names "AC3816," "AC3816N," "AC3832," "AC4030," "AC3364," and "IM101"; and those manufactured by Hitachi Chemical Industries, Ltd. Examples of such acrylic resins include, but are not limited to, those manufactured by Kaneka Corporation under the trade names "MX-153," "MX-257," [MX-154], "MX-960," "MX-136," "MX-965," "MX-217," and "MR-01"; those manufactured by Dow Chemical Japan under the trade names "EXL-2655," "TMS-2670J," and "TMS-2670S"; and those manufactured by Nissin Chemical Industry Co., Ltd. under the trade names "R-170S," [R-180S], and "R-200."

[0080] The average particle diameter of the core-shell rubber (E) is, for example, 0.001 μm or more and 1 μm or less, and preferably 0.5 μm or less.

[0081] The content of the core-shell rubber (E) is preferably 10% by mass or more, more preferably 17.5% by mass or more, based on the total amount of the resin components of the resin composition. The content of the core-shell rubber (E) is preferably 50% by mass or less, more preferably 40% by mass or less, based on the total amount of the resin components of the resin composition. In the present disclosure, the term "resin component" refers to the non-volatile components in the resin composition excluding the inorganic filler (C).

[0082] <Additives> The components and the content of the additives are not particularly limited as long as they do not impair the effects of this embodiment.

[0083] Examples of the additives include, but are not limited to, curing agents and curing accelerators other than the amine compound (D), thermoplastic resins, flame retardants, colorants, coupling agents, heat stabilizers, antioxidants, reaction initiators, antifoaming agents, antistatic agents, dyes, pigments, polymerization inhibitors, and lubricants.

[0084] Examples of the curing agent and curing accelerator other than the amine compound (D) include acid anhydrides, cyanate ester compounds, triphenylphosphine, thiol compounds, and organic acid metal salts such as metal soaps.

[0085] (1.2) Method for preparing resin composition

[0033] Examples of methods for preparing a resin composition include, but are not limited to, a method of mixing an epoxy resin (A1) and a maleimide resin (A2) as the thermosetting resin (A), a coumarin compound (B), and an inorganic filler (C) to a predetermined content. If necessary, a phenolic resin (A3), an amine compound (D), a core-shell rubber (E), and additives may be appropriately added and mixed.

[0086] Furthermore, the resin composition may contain an organic solvent. That is, the resin composition is preferably used as a resin composition in a varnish state containing an organic solvent. Note that the resin composition in a varnish state is a resin composition in which an organic solvent is further added in addition to the components contained in the above resin composition.

[0087] The varnish-state resin composition is prepared as follows. First, among the components contained in the resin composition, components that are soluble in an organic solvent are added to an organic solvent and stirred and mixed to prepare a mixture. Alternatively, this mixture may be prepared by stirring and mixing while heating. Next, components that are insoluble in an organic solvent are added to the mixture and dispersed using a ball mill, bead mill, planetary mixer, or the like until the desired dispersion state is achieved, thereby preparing a varnish-state resin composition. The organic solvent used here is not particularly limited, but is preferably one that can dissolve the thermosetting resin (A), the coumarin compound (B), etc., and does not inhibit the curing reaction of the resin composition. Examples of organic solvents include, but are not limited to, toluene and methyl ethyl ketone (MEK).

[0088] (2) Application Examples of Resin Composition Application examples of the resin composition will be described with reference to FIGS. 1 to 6. FIG.

[0089] By using the resin composition, a prepreg 1, a resin-coated film 2, a resin-coated metal foil 3, a metal-clad laminate 4, and a printed wiring board 5 can be obtained.

[0090] More specifically, the resin layer 10 of the prepreg 1 contains at least one of a resin composition and a semi-cured product of the resin composition. The resin layer 20 of the resin-coated film 2 contains at least one of a resin composition and a semi-cured product of the resin composition. The resin layer 30 of the resin-coated metal foil 3 contains at least one of a resin composition and a semi-cured product of the resin composition. The insulating layer 40 of the metal-clad laminate 4 contains a cured product of the resin composition. The insulating layer 50 of the printed wiring board 5 contains a cured product of the resin composition.

[0091] In this embodiment, the resin composition is an uncured product, and is in an early stage where it is soluble and fusible in a certain liquid, i.e., the uncured resin composition is in the A stage.

[0092] In this embodiment, the semi-cured product refers to a resin composition that has been partially cured to the extent that it can be further cured. For example, when the resin composition according to this embodiment is heated, the viscosity gradually decreases at the beginning of heating, but as the curing of the resin composition begins, the viscosity gradually increases. In this way, the semi-cured product refers to a resin composition that has been semi-cured, that is, a resin composition that has been brought to a B-stage.

[0093] (2.1) Prepreg Fig. 1 shows an example of a prepreg 1 according to this embodiment. The prepreg 1 is in a film or sheet shape as a whole. The prepreg 1 is used to manufacture a metal-clad laminate 4 and a printed wiring board 5. Specifically, the prepreg 1 is used as a material for the metal-clad laminate 4, a material for the printed wiring board 5, and for multi-layering the printed wiring board 5 (build-up method), etc.

[0094] The prepreg 1 includes at least one of a resin composition and a semi-cured product of the resin composition. The prepreg 1 may also include a resin layer 10, as shown in FIG. 1 . That is, the resin layer 10 includes at least one of a resin composition and a semi-cured product of the resin composition. The resin layer 10 further includes a fibrous base material 11. That is, the prepreg 1 may also include a resin layer 10 that includes at least one of a resin composition and a semi-cured product of the resin composition in the fibrous base material 11.

[0095] Furthermore, the prepreg 1 obtained using the resin composition may contain a semi-cured resin composition, as described above, or may contain an uncured resin composition, i.e., an uncured resin composition.

[0096] As described above, the prepreg 1 may include a resin layer 10 obtained by impregnating a fibrous base material 11 with at least one of a resin composition and a semi-cured product of a resin composition. When impregnating the fibrous base material 11 with at least one of a resin composition and a semi-cured product of a resin composition, it is preferable to use a varnish produced from the resin composition.

[0097] As shown in FIG. 1 , the prepreg 1 has one fibrous base material 11 , but may have two or more fibrous base materials 11 .

[0098] The fibrous substrate 11 is a reinforcing material, and examples thereof include, but are not limited to, glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. In particular, the use of glass cloth can result in a laminate with excellent mechanical strength. The glass type of the glass cloth is not particularly limited, but examples include E glass, S glass, Q glass, T glass, TS glass, NE glass, and L glass. When the prepreg 1 uses glass cloth as the fibrous substrate 11, the prepreg 1 can achieve the effects of the present application regardless of the glass type of the glass cloth. The glass cloth is preferably flattened. Specifically, flattening processing can be performed by continuously pressing the glass cloth with a press roll at an appropriate pressure to compress the yarns flat. The thickness of the fibrous substrate 11 typically used is, for example, 10 μm to 180 μm, but is not particularly limited. The glass cloth contains glass fibers, but may also contain reinforcing fibers other than glass fibers. The glass cloth may be surface-treated with a coupling agent or the like before being impregnated with the resin composition in a varnish state. When the glass cloth is surface-treated, the adhesion between the glass cloth and the resin composition can be improved. Examples of surface treatments include those that can be used to treat the inorganic filler (C) described above, but are not particularly limited.

[0099] The thickness of the prepreg 1 is, for example, in the range of 10 μm to 200 μm, but is not particularly limited.

[0100] Furthermore, in obtaining the resin layer 10, the fibrous substrate 11 is impregnated with the varnish by immersing the fibrous substrate 11 in the varnish or by applying the varnish to the fibrous substrate 11, and the impregnation can be repeated multiple times as necessary. In this case, by repeating the impregnation using multiple varnishes with different compositions and concentrations, it is possible to obtain a resin layer 10 containing a resin composition or a semi-cured product of a resin composition with a desired composition and impregnation amount.

[0101] Furthermore, in the method for producing the prepreg 1, for example, a resin layer 10 produced by impregnating a fibrous substrate 11 with a varnish containing a resin composition and an organic solvent may be heated to reduce or remove the organic solvent from the resin layer 10. Conditions for reducing or removing the organic solvent from the resin layer 10 by heating the resin layer 10 include, for example, a temperature of 80°C or higher and 180°C or lower and a time of 1 minute or higher and 10 minutes or lower.

[0102] The method for producing the prepreg 1 including at least one of the resin composition and the semi-cured resin composition according to the present embodiment and the fibrous base material 11 is not limited to the above-described method. In other words, the prepreg 1 produced using the resin composition according to the present embodiment can be produced by any appropriate method.

[0103] Furthermore, if the prepreg 1 is manufactured using a general manufacturing method, the surface roughness of the cured product does not affect the reflectance. In other words, the reflectance of the cured prepreg 1 is not affected by the surface roughness and depends only on the composition of the resin composition. Therefore, the cured prepreg 1 manufactured using the above-mentioned resin composition can have a reflectance of 20% or less for light with a wavelength of 365 nm or more and 405 nm or less, regardless of the surface roughness. The surface roughness of the cured prepreg 1 is expressed, for example, by the arithmetic mean roughness Sa. This arithmetic mean height Sa is not particularly limited, but is, for example, 0.01 μm or more and 2 μm or less.

[0104] Because the prepreg 1 according to this embodiment is produced using the resin composition according to this embodiment, it is possible to achieve the following: a glass transition temperature of a cured product of the resin composition of 200°C or higher; good desmear resistance of the cured product of the resin composition; and a reflectance of the cured product of the resin composition of 20% or lower for light with a wavelength of 365 nm or higher and 405 nm or lower, and good small-diameter opening properties of the solder resist 8 formed on the printed wiring board 5 produced using the resin composition. Furthermore, the prepreg 1 according to this embodiment is not limited to use in the production of printed wiring boards 5, but is applicable to a variety of uses.

[0105] The prepreg 1 is a type of resin-impregnated substrate. The resin-impregnated substrate is a fibrous substrate impregnated with a resin composition or a semi-cured resin composition. Examples of resin-impregnated substrates other than the prepreg 1 include resin cloth.

[0106] (2.2) Resin-Coated Film Figures 2 and 3 show an example of the resin-coated film 2 according to this embodiment. The resin-coated film 2 is generally in the form of a film or sheet. The resin-coated film 2 is used for multi-layering (build-up method) of a printed wiring board 5, etc.

[0107] The resin-coated film 2 comprises a resin layer 20 containing at least one of a resin composition and a semi-cured product of a resin composition, and a support film 21. That is, the resin-coated film 2 comprises a resin layer 20 containing at least one of a resin composition and a semi-cured product of a resin composition, and a support film 21 overlapping the resin layer 20. The resin-coated film 2 may comprise another layer between the resin layer 20 and the support film 21.

[0108] Furthermore, as described above, the resin layer 20 may contain a semi-cured product of the resin composition, or may contain an uncured product of the resin composition. That is, the resin-coated film 2 may be a resin-coated film 2 including a resin layer 20 including a semi-cured product of the resin composition and a support film 21, or a resin-coated film 2 including a resin layer 20 including an uncured product of the resin composition before curing and a support film 21.

[0109] The resin layer 20 may or may not include a fibrous base material (not shown). When the resin layer 20 includes a fibrous base material, the same fibrous base material as the fibrous base material 11 of the prepreg 1 can be used. In other words, the resin layer may be produced from the prepreg 1.

[0110] The support film 21 supports the resin layer 20. In this way, the support film 21 supports the resin layer 20, which can make the resin layer 20 easier to handle.

[0111] The support film 21 is, for example, an electrically insulating film, but is not particularly limited to, for example, a polyethylene terephthalate (PET) film, a polyimide film, a polyester film, a polyparabanic acid film, a polyether ether ketone film, a polyphenylene sulfide film, a polyamide film, a polycarbonate film, a polyarylate film, or the like.

[0112] A release agent layer (not shown) may be provided on the surface of the support film 21 that supports the resin layer 20. This release agent layer allows the support film 21 to be peeled from the resin layer 20 as needed. Preferably, the resin layer 20 is cured to form an insulating layer, and then the support film 21 is peeled from this insulating layer.

[0113] 2, one surface of the resin layer 20 is covered with a support film 21, but as shown in Fig. 3, the other surface of the resin layer 20 may be covered with a cover film 22. By covering both surfaces of the resin layer 20, the resin layer 20 can be made easier to handle and adhesion of foreign matter to the resin layer 20 can be suppressed.

[0114] The cover film 22 is, for example, an electrically insulating film, but is not particularly limited thereto. Examples of the cover film 22 include, but are not particularly limited to, polyethylene terephthalate (PET) film, polyolefin film, polyester film, and polymethylpentene film. A release agent layer (not shown) may be further provided between the resin layer 20 and the cover film 22. The release agent layer allows the cover film 22 to be peeled from the resin layer 20 as necessary.

[0115] The support film 21 and the cover film 22 may be subjected to surface treatment such as matte treatment, corona treatment, release treatment, or roughening treatment, if necessary.

[0116] The thickness of the resin layer 20 is not particularly limited, but is preferably 120 μm or less, more preferably 100 μm or less, even more preferably 60 μm or less, and even more preferably 40 μm or less. This allows the thickness of the insulating layer to be thin, thereby realizing a thinner printed wiring board 5. In addition, the thickness of the resin layer is preferably 10 μm or more.

[0117] The resin layer 20 is produced by applying a resin composition to the support film 21. Examples of methods for applying the resin composition include, but are not limited to, methods using a bar coater, a die coater, a doctor blade, a baker applicator, etc. When applying the resin layer 20 to the support film 21, it is preferable to use a resin composition in a varnish state. As described above, by heating the varnish applied to the support film 21, the organic solvent can be volatilized from the varnish, thereby reducing or removing the organic solvent. The applied varnish is heated, for example, at a temperature of 80°C or higher and 180°C or lower for a time period of 1 minute to 10 minutes. In other words, the conditions for reducing or removing the organic solvent from the resin layer 20 by heating the resin layer 20 may be the same as the conditions for reducing or removing the organic solvent from the resin layer 10 by heating the resin layer 10 when producing the prepreg 1. In this way, a resin layer 20 containing at least one of a resin composition and a semi-cured product of a resin composition is formed on the support film 21, thereby producing a resin-coated film 2.

[0118] The method for producing the resin-coated film 2 including the resin layer 20 containing the resin composition or semi-cured product of the resin composition according to this embodiment and the support film 21 supporting the resin layer 20 is not limited to the above-described method. In other words, the resin-coated film 2 produced using the resin composition according to this embodiment can be produced by any appropriate method.

[0119] Furthermore, for resin-coated films 2 manufactured using a typical manufacturing method, the surface roughness of the cured resin layer 20 does not affect reflectance. That is, the reflectance of the cured resin layer 20 is not affected by surface roughness and depends only on the composition of the resin composition. Therefore, the cured resin layer 20 manufactured using the above-mentioned resin composition can have a reflectance of 20% or less for light with a wavelength of 365 nm or more and 405 nm or less, regardless of surface roughness. The surface roughness of the cured resin layer 20 is expressed, for example, by the arithmetic mean roughness Sa. This arithmetic mean height Sa is not particularly limited, but is, for example, 0.01 μm or more and 2 μm or less.

[0120] Because the resin layer 20 of the resin-fitted film 2 according to this embodiment is produced using the resin composition according to this embodiment, it is possible to achieve the following: a glass transition temperature of a cured product of the resin composition of 200° C. or higher; good desmear resistance of the cured product of the resin composition; and a reflectance of the cured product of the resin composition of 20% or lower for light with a wavelength of 365 nm or higher and 405 nm or lower, and good small-diameter opening properties of the solder resist 8 formed on the printed wiring board 5 produced using the resin composition. Furthermore, the resin-fitted film 2 according to this embodiment is not limited to use in the production of printed wiring boards 5, but is applicable to a variety of uses.

[0121] (2.3) Resin-Coated Metal Foil Fig. 4 shows an example of the resin-coated metal foil 3 according to this embodiment. The resin-coated metal foil 3 is generally in the form of a film or sheet. The resin-coated metal foil 3 is used for multilayering of a printed wiring board 5 (build-up method), etc.

[0122] The resin-coated metal foil 3 includes a resin layer 30 containing at least one of a resin composition and a semi-cured product of a resin composition, and a metal foil 31. The resin-coated metal foil 3 may also include another layer between the resin layer 30 and the metal foil 31.

[0123] As described above, the resin layer 30 may contain a semi-cured resin composition, or may contain an uncured resin composition. That is, the resin-coated metal foil 3 may be a resin-coated metal foil 3 including a resin layer 30 including a semi-cured resin composition and a metal foil 31, or a resin-coated metal foil 3 including a resin layer 30 including an uncured resin composition before curing and a metal foil 31.

[0124] The resin layer 30 may or may not include a fibrous base material (not shown). When the resin layer 30 includes a fibrous base material, the same fibrous base material as the fibrous base material 11 of the prepreg 1 can be used. In other words, the resin layer 30 can be produced from the prepreg 1.

[0125] Examples of the metal foil 31 include, but are not limited to, copper foil and aluminum foil. The metal foil 31 can be used as the conductor wiring 51 of the printed wiring board 5 by removing unnecessary portions by etching using a subtractive method or the like.

[0126] Furthermore, the resin-coated metal foil 3 may be provided with a cover film (not shown) or the like, if necessary. The cover film may be the same as that used in the resin-coated film 2 described above.

[0127] The resin layer 30 is produced by applying a resin composition to the metal foil 31. Methods for applying the resin composition include, but are not limited to, methods using a bar coater, a die coater, a doctor blade, a baker applicator, etc. When applying the resin composition to the metal foil 31, it is preferable to use a resin composition in a varnish state.

[0128] As described above, by heating the varnish applied to the metal foil 31, the organic solvent can be volatilized from the varnish, thereby reducing or removing the organic solvent. The applied varnish can be heated, for example, at a temperature of 80°C or higher and 180°C or lower for a period of 1 minute or higher and 10 minutes or shorter. In other words, the conditions for reducing or removing the organic solvent from the resin layer 30 by heating the resin layer 30 may be the same as the conditions for reducing or removing the organic solvent from the resin layer 10 by heating the resin layer 10 when producing the prepreg 1.

[0129] The method for producing the resin-coated metal foil 3 including the resin layer 30 containing the resin composition or a semi-cured product of the resin composition according to the present embodiment and the metal foil 31 adhered to the resin layer 30 is not limited to the above-described method. In other words, the resin-coated metal foil 3 produced using the resin composition according to the present embodiment can be produced by any appropriate method.

[0130] Furthermore, for resin-coated metal foil 3 manufactured by a typical manufacturing method, the surface roughness of the cured resin layer 30 does not affect the reflectance. In other words, the reflectance of the cured resin layer 30 is not affected by the surface roughness and depends only on the composition of the resin composition. Therefore, the cured resin layer 30 manufactured using the above-mentioned resin composition can have a reflectance of 20% or less for light with a wavelength of 365 nm or more and 405 nm or less, regardless of the surface roughness. The surface roughness of the cured resin layer 30 is expressed, for example, by the arithmetic mean roughness Sa. This arithmetic mean height Sa is not particularly limited, but is, for example, 0.01 μm or more and 2 μm or less.

[0131] The resin layer 30 of the resin-coated metal foil 3 according to this embodiment is produced using the resin composition according to this embodiment, and therefore it is possible to achieve the following: a glass transition temperature of a cured product of the resin composition of 200°C or higher; good desmear resistance of the cured product of the resin composition; and a reflectance of the cured product of the resin composition of 20% or lower for light with a wavelength of 365 nm or higher and 405 nm or lower, and good small-diameter opening properties of the solder resist 8 formed on the printed wiring board 5 produced using the resin composition. Furthermore, the resin-coated metal foil 3 according to this embodiment is not limited to use in the production of printed wiring boards, but is applicable to a variety of other applications.

[0132] (2.4) Metal-clad laminate Fig. 5 shows an example of a metal-clad laminate 4 according to this embodiment. The metal-clad laminate 4 includes an insulating layer 40 containing a cured product of the resin composition according to this embodiment, and a metal layer 41 overlapping the insulating layer 40. The metal-clad laminate 4 is used as a material for a printed wiring board 5, etc.

[0133] Examples of methods for producing the metal-clad laminate 4 include a method of producing the metal-clad laminate 4 by overlapping a resin composition or a semi-cured product of the resin composition with a metal layer 41, and heating and pressurizing the resin composition to cure the resin composition and form the insulating layer 40. More specifically, a metal layer 41 such as copper foil is overlapped on one or both sides of the resin composition or the semi-cured product of the resin composition, and the resin composition or the semi-cured product of the resin composition and the metal layer 41 are molded under heat and pressure to cure the resin composition and form the insulating layer 40. By laminating and integrating the insulating layer 40 including the cured product of the resin composition and the metal layer 41, a metal-clad laminate 4 can be produced in which the metal layer 41 is adhered to one or both sides of the insulating layer 40 including the cured product of the resin composition.

[0134] The insulating layer 40 may also be manufactured using the above-described prepreg 1. More specifically, the prepreg 1 and the metal layer 41 are heated and pressurized to harden the prepreg 1 and form the insulating layer 40, and the insulating layer 40 containing the cured prepreg 1 and the metal layer 41 are laminated together to manufacture a metal-clad laminate 4 in which the metal layer 41 is adhered to one or both sides of the insulating layer 40 containing the cured prepreg 1. When the metal-clad laminate 4 is manufactured using the prepreg 1, the insulating layer 40 has a fibrous base material 42 as shown in FIG. 5 . The metal-clad laminate 4 may have only one fibrous base material 42, or two or more fibrous base materials 42.

[0135] Furthermore, the insulating layer 40 may be manufactured using the resin-coated film 2 and resin-coated metal foil 3 described above. More specifically, the resin layer 20 of the resin-coated film 2 or the resin layer 30 of the resin-coated metal foil 3 and the metal layer 41 are heated and pressurized to cure the resin layer 20 of the resin-coated film 2 or the resin layer 30 of the resin-coated metal foil 3 to form the insulating layer 40, and the insulating layer 40 containing the cured product of the resin layer 20 of the resin-coated film 2 or the cured product of the resin layer 30 of the resin-coated metal foil 3 is laminated integrally with the metal layer 41 to manufacture a metal-clad laminate 4 in which the metal layer 41 is adhered to one or both sides of the insulating layer 40 containing the cured product of the resin layer 20 of the resin-coated film 2 or the cured product of the resin layer 30 of the resin-coated metal foil 3. Here, when manufacturing using the resin-coated metal foil 3, the metal foil 31 of the resin-coated metal foil 3 becomes the metal layer 41 in the metal-clad laminate 4.

[0136] The heating and pressing conditions when producing the metal-clad laminate 4 can be appropriately set depending on the thickness of the metal-clad laminate 4 to be produced and the type and components of the resin composition that forms the insulating layer 40 .

[0137] The heating temperature when manufacturing the metal-clad laminate 4 is, for example, 200° C. or higher and 250° C. or lower. The pressure when manufacturing the metal-clad laminate 4 is, for example, 1 MPa or higher and 5 MPa or lower. The heating and pressing time when manufacturing the metal-clad laminate 4 is, for example, 30 minutes or higher and 120 minutes or lower.

[0138] When manufacturing the metal-clad laminate 4, the thickness of the metal layer 41 can be appropriately set depending on the desired purpose. The thickness of the metal layer 41 is, for example, 5 μm or more and 35 μm or less, but is not particularly limited. When an ultrathin metal foil is used as the metal layer 41, a carrier-attached metal foil having a release layer and a carrier may be used to improve handling properties.

[0139] The method for producing the metal-clad laminate 4 including the insulating layer 40 containing the cured product of the resin composition or prepreg 1 according to the present embodiment and the metal layer 41 adhered to the insulating layer 40 is not limited to the above method. In other words, the metal-clad laminate 4 produced using the resin composition or prepreg 1 according to the present embodiment can be produced by any appropriate method.

[0140] Furthermore, for metal-clad laminates 4 manufactured using a typical manufacturing method, the surface roughness of the insulating layer 40 does not affect the reflectance. In other words, the reflectance of the insulating layer 40 is not affected by the surface roughness and depends only on the composition of the resin composition. Therefore, the insulating layer 40 manufactured using the above-mentioned resin composition can have a reflectance of 20% or less for light with a wavelength of 365 nm or more and 405 nm or less, regardless of the surface roughness. The surface roughness of the insulating layer 40 is expressed, for example, by the arithmetic mean roughness Sa. This arithmetic mean height Sa is not particularly limited, but is, for example, 0.01 μm or more and 2 μm or less.

[0141] The insulating layer 40 of the metal-clad laminate 4 according to this embodiment is manufactured using the resin composition or prepreg 1 according to this embodiment, and therefore it is possible to achieve the following: a glass transition temperature of the cured product of the resin composition of 200° C. or higher; good desmear resistance of the cured product of the resin composition; and a reflectance of the cured product of the resin composition of 20% or lower for light with a wavelength of 365 nm or higher and 405 nm or lower, and good small-diameter opening properties of the solder resist 8 formed on the printed wiring board 5 manufactured using the resin composition or prepreg 1. Furthermore, the metal-clad laminate 4 according to this embodiment is not limited to use in the manufacture of printed wiring boards 5, but is applicable to a variety of uses.

[0142] (2.5) Printed Wiring Board Fig. 6 shows an example of a printed wiring board 5 according to this embodiment. The printed wiring board 5 includes an insulating layer 50 containing a cured product of a resin composition, and conductor wiring 51 overlapping the insulating layer 50. The conductor wiring 51 may be formed on only one side of the insulating layer 50, or on both sides.

[0143] The insulating layer 50 may include a cured product of the above-described prepreg 1. That is, the printed wiring board 5 includes an insulating layer 50 manufactured using the prepreg 1 and conductor wiring 51 overlapping the insulating layer 50. The conductor wiring 51 may be formed on only one side of the insulating layer 50, or may be formed on both sides. When the printed wiring board 5 is manufactured using the prepreg 1, it has a fibrous base material 52 as shown in FIG. 6. The printed wiring board 5 may have only one fibrous base material 52, or two or more fibrous base materials 52.

[0144] The printed wiring board 5 may also be manufactured using the above-described metal-clad laminate 4. More specifically, the conductor wiring 51 can be formed by subjecting the metal layer 41 on the surface of the metal-clad laminate 4 to etching or the like. That is, the conductor wiring 51 can be formed in the printed wiring board 5 by partially removing the metal layer 41 on the surface of the metal-clad laminate 4. In this manner, a printed wiring board 5 can be manufactured that includes an insulating layer 50 and conductor wiring 51 as a circuit on one or both sides of the insulating layer 50.

[0145] Furthermore, examples of methods for forming a circuit other than the above-mentioned methods include, but are not limited to, circuit formation by a semi-additive process (SAP) and a modified semi-additive process (MSAP).

[0146] In addition, for printed wiring board 5 manufactured by a typical manufacturing method, the surface roughness of insulating layer 50 does not affect reflectance. In other words, the reflectance of insulating layer 50 is not affected by surface roughness and depends only on the composition of the resin composition. Therefore, insulating layer 50 manufactured using the above-mentioned resin composition can have a reflectance of 20% or less for light with a wavelength of 365 nm or more and 405 nm or less, regardless of surface roughness. The surface roughness of insulating layer 50 is expressed, for example, by arithmetic mean roughness Sa. This arithmetic mean height Sa is not particularly limited, but is, for example, 0.01 μm or more and 2 μm or less.

[0147] Since the insulating layer 50 of the printed wiring board 5 according to the present embodiment is produced using the resin composition or prepreg 1 according to the present embodiment, it is possible to achieve the following: the glass transition temperature of the cured product of the resin composition is 200°C or higher; the desmear resistance of the cured product of the resin composition is good; the reflectance of the cured product of the resin composition for light with a wavelength of 365 nm or higher and 405 nm or lower is 20% or lower; and the small diameter opening property of the solder resist 8 formed on the printed wiring board 5 produced using the resin composition or prepreg 1 is good.

[0148] 3. Aspects As is clear from the above embodiment, the present disclosure includes the following aspects. In the following, reference numerals are given in parentheses only to clarify the correspondence with the embodiment.

[0149] The resin composition according to a first aspect contains a thermosetting resin (A), a coumarin compound (B), and an inorganic filler (C). The thermosetting resin (A) contains an epoxy resin (A1) and a maleimide resin (A2). The content of the maleimide resin (A2) is 8% by mass or more and 60% by mass or less, based on the total amount of the thermosetting resin (A).

[0150] According to this embodiment, the cured product of the resin composition has a high glass transition temperature and good desmear resistance, and the solder resist (8) formed on the printed wiring board (5) produced using the resin composition has good small-diameter opening properties.

[0151] A second aspect is a resin composition based on the first aspect. In the second aspect, the coumarin compound (B) includes a coumarin compound (B1) represented by at least one of formula (1) and formula (2):

[0152]

[0153]

[0154] (In formula (1) and formula (2), R1 and R2 each independently represent a hydrogen atom, an alkyl group, an aryl group, or a hydroxyalkyl group. R3, R4, and R5 each independently represent a hydrogen atom, an alkyl group, or an aryl group.)

[0155] A third aspect is a resin composition based on the first or second aspect. In the third aspect, the mass ratio of the epoxy resin (A1) to the maleimide resin (A2) is 10:1 to 2:5.

[0156] A fourth aspect is a resin composition based on any one of aspects 1 to 3. In the fourth aspect, the epoxy resin (A1) includes at least one selected from the group consisting of biphenyl-type epoxy resins, naphthalene-type epoxy resins, and dicyclopentadiene-type epoxy resins.

[0157] A fifth aspect is a resin composition based on any one of aspects 1 to 4. In the fifth aspect, the thermosetting resin (A) further contains a phenolic resin (A3).

[0158] A sixth aspect is a resin composition based on any one of aspects 1 to 5. In the sixth aspect, the content of the coumarin compound (B) is 0.4% by mass or more and 10% by mass or less, based on the total amount of the thermosetting resin (A) and the coumarin compound (B).

[0159] A seventh aspect is a resin composition based on any one of aspects 1 to 6. In the seventh aspect, the content of the inorganic filler (C) is 50 parts by mass or more and 300 parts by mass or less per 100 parts by mass of the total of the thermosetting resin (A) and the coumarin compound (B).

[0160] An eighth aspect is a resin composition based on any one of aspects 1 to 7. In the eighth aspect, the resin composition further contains an amine compound (D) that does not have a coumarin skeleton.

[0161] A ninth aspect is a resin composition based on any one of the first to eighth aspects. In the ninth aspect, the resin composition further contains a core-shell rubber (E).

[0162] A tenth aspect is a resin composition based on any one of aspects 1 to 9. In the tenth aspect, the inorganic filler (C) includes at least one filler selected from the group consisting of silica, talc, boehmite, magnesium hydroxide, and aluminum hydroxide.

[0163] The prepreg (1) according to the eleventh aspect comprises at least one of a resin composition and a semi-cured resin composition based on any one of the first to tenth aspects, and a fibrous base material (11).

[0164] The resin-coated film (2) according to the twelfth aspect comprises a resin layer (20) containing at least one of a resin composition based on any one of the first to tenth aspects and a semi-cured product of the resin composition, and a support film (21).

[0165] The resin-coated metal foil (3) according to the thirteenth aspect comprises a resin layer (30) containing at least one of a resin composition based on any one of the first to tenth aspects and a semi-cured product of the resin composition, and a metal foil (31).

[0166] The metal-clad laminate (4) according to the fourteenth aspect comprises an insulating layer (40) containing a cured product of a resin composition based on any one of the first to tenth aspects, and a metal layer (41).

[0167] A metal-clad laminate (4) according to a fifteenth aspect includes an insulating layer (40) containing a cured product of the prepreg (1) according to the eleventh aspect, and a metal layer (41).

[0168] A printed wiring board (5) according to a sixteenth aspect includes an insulating layer (50) containing a cured product of a resin composition based on any one of the first to tenth aspects, and conductor wiring (51).

[0169] A printed wiring board (5) according to a seventeenth aspect comprises an insulating layer (50) containing a cured product of the prepreg (1) according to the eleventh aspect, and conductor wiring (51).

[0170] The present disclosure will be specifically described below using examples, but the present disclosure is not limited to the following examples.

[0171] (1) Resin Composition The components shown in Tables 1 and 2 were used as raw materials for the resin compositions. The thermosetting resin (A), coumarin compound (B), inorganic filler (C), amine compound (D), and core-shell rubber (E) were blended in the amounts shown in Tables 1 and 2, diluted with a solvent (methyl ethyl ketone), and homogenized by stirring and mixing to prepare each resin composition in a varnish state for the Examples and Comparative Examples. Details of each component used are as follows:

[0172] (1.1) Thermosetting Resin (A) <Epoxy Resin (A1)> - Epoxy Resin #1: Manufactured by DIC Corporation, product name "EPICLON HP-9500", naphthalene type epoxy resin, epoxy equivalent 220 to 240 g / eq. - Epoxy Resin #2: Manufactured by Nippon Kayaku Co., Ltd., product name "NC-3500", biphenyl type epoxy resin, epoxy equivalent 209 g / eq. - Epoxy Resin #3: Manufactured by Nippon Kayaku Co., Ltd., product name "NC-3000H", biphenyl type epoxy resin, epoxy equivalent 280 to 300 g / eq.

[0173] <Maleimide resin (A2)> Maleimide resin #1: manufactured by Daiwa Chemical Industry Co., Ltd., product name "BMI-2300" Maleimide resin #2: manufactured by Nippon Kayaku Co., Ltd., product name "MIR-3000-70MT".

[0174] <Phenolic Resin (A3)> Phenolic Resin #1: Manufactured by Nippon Kayaku Co., Ltd., product name "GPH-103", biphenyl-type phenolic resin, phenolic hydroxyl group equivalent 231 g / eq. Phenolic Resin #2: Manufactured by Dow Chemical Japan, product name "XZ92741", phosphorus-containing phenolic resin, phenolic hydroxyl group equivalent 550 g / eq. Phenolic Resin #3: Manufactured by Meiwa Kasei Co., Ltd., product name "MEHC-7403H", biphenyl-type phenolic resin, phenolic hydroxyl group equivalent 132 g / eq.

[0175] (1.2) Coumarin Compound (B) Coumarin Compound #1: manufactured by Tokyo Chemical Industry Co., Ltd., compound name "7-amino-4-methylcoumarin".

[0176] (1.3) Inorganic Filler (C) - Inorganic Filler #1: manufactured by Admatechs Co., Ltd., product name "SC2500-SXJ", aminosilane-treated silica, average particle size (D50): 0.5 μm.

[0177] (1.4) Amine Compound (D) - Amine Compound #1: manufactured by Shikoku Chemicals Corporation, product name "2E4MZ", compound name "2-ethyl-4-methylimidazole".

[0178] (1.5) Core-shell rubber (E) - Core-shell rubber #1: manufactured by Mitsubishi Chemical Corporation, product name "SRK200A", core; silicone, shell; styrene-acrylonitrile copolymer, average particle size (D50); 0.15 μm.

[0179] (2) Prepreg A glass cloth (Nitto Boseki Co., Ltd., #2118 type, WEA2118T-107-S199, E-glass) was prepared as a fibrous substrate. This glass cloth was made of a woven fabric in which warp and weft threads were woven so that they intersected approximately perpendicularly. This glass cloth was impregnated with a varnish-state resin composition so that the thickness of the cured prepreg was 100 μm. The resin composition impregnated into the glass cloth was heated and dried at 130°C using a non-contact heating unit until it became a semi-cured product. This removed the solvent from the resin composition, and a prepreg was obtained that included glass cloth and a semi-cured product of the resin composition impregnated into the glass cloth. The content of the resin layer 10 in the prepreg was 46% by mass, with the entire prepreg being 100% by mass.

[0180] (3) Metal-clad laminate Two prepregs obtained as described above were stacked to obtain a laminate, and copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm, 3EC-VLP-12) was stacked on both sides of the obtained laminate as a metal layer to obtain a copper foil-attached laminate. This copper foil-attached laminate was heated and press-molded to obtain a 0.2 mm-thick metal-clad laminate having metal layers on both sides. The conditions for the heat and pressure molding were 220°C, 2 MPa, and 90 minutes.

[0181] (4) Test (4.1) Glass Transition Temperature The copper foils adhered to both sides of the metal-clad laminate were removed by etching to obtain an unclad plate, which was then cut at an angle of 45° (bias direction) relative to the warp or weft of the glass cloth to obtain test pieces measuring 50 mm × 5 mm × 0.2 mm.

[0182] The tan δ of this test piece was measured using a dynamic viscoelasticity measuring device (manufactured by SII NanoTechnology Inc., "DMS6100") under a temperature increase condition of 5°C / min (DMA method), and the peak temperature was taken as the glass transition temperature.

[0183] (4.2) Reflectance The copper foils adhered to both sides of the metal-clad laminate were removed by etching to obtain an unclad plate. A test piece measuring 50 mm x 50 mm x 0.2 mm was obtained from this unclad plate.

[0184] For this test piece, the reflectance of light rays with wavelengths of 365 nm, 385 nm, 395 nm, and 405 nm in the thickness direction of the test piece was measured using an ultraviolet-visible spectrophotometer (Shimadzu Corporation, "UV-2500PC") The reflectance was measured by relative total light reflectance measurement using an integrating sphere attachment (integrating sphere inner diameter: Φ60 mm, barium sulfate paint type) at an incident angle of 5° and in reflectance measurement mode.

[0185] (4.3) Small-Diameter Opening Property of Solder Resist First, the copper foil adhered to a 5 cm × 5 cm metal-clad laminate was removed by etching to obtain an unclad plate. A photosensitive dry film solder resist (PSR-800 AUS410, manufactured by Taiyo Ink Mfg. Co., Ltd., thickness: 20 μm, negative type) was attached to the entire surface of this unclad plate using a vacuum laminator under the conditions of a lamination temperature of 75°C, a vacuum holding time of 20 seconds, and a pressing time of 60 seconds to obtain a test piece.

[0186] Next, the obtained test piece was exposed to light through a photomask on which an opening pattern with a spot diameter of 100 μm or 60 μm was drawn, using an exposure device equipped with a metal halide lamp (manufactured by ORC Manufacturing Co., Ltd., "HMW-680 GW20") at 20°C with an accumulated exposure dose of 600 mJ / cm. ２ 7 to 9, the non-irradiated inner edge portion 6 refers to the inner edge portion of the portion that is not irradiated with light having a wavelength of 365 nm or more and 405 nm or less due to the photomask.

[0187] After exposure, the test pieces were subjected to a development process by spray development. The development process involved spraying a 1% by mass aqueous solution of sodium bicarbonate at 30°C as a developer at a spray pressure of 0.2 MPa for 120 seconds. After the development process, the test pieces were washed with water at 25°C and a spray pressure of 0.1 MPa for 45 seconds. After the water washing process, the test pieces were post-cured at 150°C for 60 minutes and then exposed to a high-pressure mercury lamp at 1000 mJ / cm. ２The dry film solder resist was cured by post-UV treatment under the conditions of (a) and (b). The post-cure treatment and post-UV treatment are intended to further cure the dry film solder resist after exposure. By these treatments, a solder resist 8 was formed on the test piece.

[0188] The unirradiated inner edge 6 of the test piece was then observed with a scanning electron microscope (SEM), and the observation results were classified according to the following evaluation criteria to evaluate the solder resist openability of each test piece.

[0189] <Evaluation Criteria> S: Solder resist opening shape is good for spot diameters of 60 μm and 100 μm. A: Solder resist opening shape is good for spot diameter 100 μm. B: Solder resist opening shape is poor for spot diameter 100 μm.

[0190] The evaluation criterion of "good solder resist opening shape" refers to a state in which, at each spot diameter, no solder resist 8 remains inside the inner edge portion 6 of the unirradiated portion, and the opening portion 7 is formed in a substantially circular shape, as shown in Figure 7. On the other hand, the evaluation criterion of "poor solder resist opening shape" refers to a state in which, at a spot diameter Φ of 100 μm, solder resist 8 remains inside the inner edge portion 6 of the unirradiated portion, the opening portion 7 is not circular, and only a portion of the inner edge portion 6 of the unirradiated portion is opened, as shown in Figure 8, or a state in which no opening 7 is formed, and solder resist 8 remains on the entire inside of the inner edge portion 6 of the unirradiated portion, as shown in Figure 9. Note that evaluation A indicates that the opening shape is good at a spot diameter Φ of 100 μm, but is not good at a spot diameter Φ of 60 μm.

[0191] If the evaluation is S or A, the solder resist has good small diameter opening properties.

[0192] (4.4) Desmear Resistance The desmear resistance was evaluated from the calculated value of the desmear etching amount calculated from the difference between the mass of the test piece before the desmear treatment and the mass of the test piece after the desmear treatment with permanganate.

[0193] Specifically, the copper foil adhered to a metal-clad laminate having a size of 5 cm x 5 cm was removed by etching to obtain a test piece. The difference (unit: mg / cm) between the mass of the test piece before desmearing (initial mass) and the mass of the test piece after desmearing under the following conditions was calculated. ２ ) The amount of desmear etching was calculated.

[0194] The initial mass of the test piece before treatment was measured after drying the test piece at 130°C for 30 minutes and then air-cooling it in a desiccator for 2 hours. The desmear treatment consisted of the following steps (a) to (d).

[0195] (a) Swelling Step First, the initial mass of the untreated test piece is measured and then swelled for 5 minutes in "Swelling Dip Securigant P (500 ml / L)" manufactured by Atotech and an aqueous solution of sodium hydroxide (40 g / L).

[0196] (b) Desmearing Step Next, microetching treatment is carried out for 10 minutes using "Concentrate Compact CP (580 ml / L)" manufactured by Atotech and an aqueous solution of sodium hydroxide (40 g / L).

[0197] (c) Neutralization Step Next, the solution is neutralized for 5 minutes with "Reduction Solution Securigant P500 (70 ml / L)" manufactured by Atotech and sulfuric acid (98%, 50 ml / L).

[0198] (d) Drying step Finally, the product is dried at 130°C for 30 minutes.

[0199] The above series of steps (a) to (c) was repeated twice, and then step (d) was carried out, after which the treated test piece was air-cooled in a desiccator for 2 hours and the mass of the treated test piece was measured. In this way, the amount of desmear etching was calculated.

[0200] The amount of desmear etching is 0.5 mg / cm ２ If the value is below, the desmear resistance is good.

[0201]

[0202]

[0203] REFERENCE SIGNS LIST 1 Prepreg 10 Resin layer 11 Fibrous base material 2 Resin-attached film 20 Resin layer 21 Support film 3 Resin-attached metal foil 30 Resin layer 31 Metal foil 4 Metal-clad laminate 40 Insulating layer 41 Metal layer 42 Fibrous base material 5 Printed wiring board 50 Insulating layer 51 Conductive wiring 52 Fibrous base material 6 Inner edge of unirradiated portion 7 Opening 8 Solder resist

Claims

1. A resin composition comprising a thermosetting resin (A), a coumarin compound (B), and an inorganic filler (C), wherein the thermosetting resin (A) comprises an epoxy resin (A1) and a maleimide resin (A2), and the content of the maleimide resin (A2) is 8% by mass or more and 60% by mass or less relative to the total amount of the thermosetting resin (A).

2. The resin composition according to claim 1, wherein the coumarin compound (B) includes a coumarin compound (B1) represented by at least one of formulas (1) and (2). (In formula (1) and formula (2), R1 and R2 each independently represent a hydrogen atom, an alkyl group, an aryl group, or a hydroxyalkyl group. R3, R4, and R5 each independently represent a hydrogen atom, an alkyl group, or an aryl group.) 3. The resin composition according to claim 1, wherein the mass ratio of the epoxy resin (A1) to the maleimide resin (A2) is 10:1 to 2:

5.

4. The resin composition according to claim 1, wherein the epoxy resin (A1) comprises at least one selected from the group consisting of biphenyl-type epoxy resins, naphthalene-type epoxy resins, and dicyclopentadiene-type epoxy resins.

5. The resin composition according to claim 1, wherein the thermosetting resin (A) further contains a phenolic resin (A3).

6. The resin composition according to claim 1, wherein the content of the coumarin compound (B) is 0.4 mass % or more and 10 mass % or less based on the total amount of the thermosetting resin (A) and the coumarin compound (B).

7. The resin composition according to claim 1, wherein the content of the inorganic filler (C) is 50 parts by mass or more and 300 parts by mass or less per 100 parts by mass of the total of the thermosetting resin (A) and the coumarin compound (B).

8. The resin composition according to claim 1, further comprising an amine compound (D) not having a coumarin skeleton.

9. The resin composition according to claim 1, further comprising a core-shell rubber (E).

10. The resin composition according to claim 1, wherein the inorganic filler (C) comprises at least one filler selected from the group consisting of silica, talc, boehmite, magnesium hydroxide, and aluminum hydroxide.

11. A prepreg comprising at least one of the resin composition according to any one of claims 1 to 10 and a semi-cured product of said resin composition, and a fibrous base material.

12. A resin-coated film comprising a resin layer containing at least one of the resin composition according to any one of claims 1 to 10 and a semi-cured product of said resin composition, and a support film.

13. A resin-coated metal foil comprising a resin layer containing at least one of the resin composition according to any one of claims 1 to 10 and a semi-cured product of said resin composition, and a metal foil.

14. A metal-clad laminate comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 10, and a metal layer.

15. A metal-clad laminate comprising an insulating layer containing the cured product of the prepreg according to claim 11 and a metal layer.

16. A printed wiring board comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 10, and conductor wiring.

17. A printed wiring board comprising an insulating layer containing the cured product of the prepreg according to claim 11 and conductor wiring.

Images