Resin composition, film with resin, metal foil with resin, prepreg, metal-clad laminate, and printed wiring boards

Abstract

The present invention discloses a resin composition having a high glass transition temperature, good resistance to solder slag removal, and good small-diameter opening properties for solder resist formation on a printed circuit board containing the aforementioned cured composition. The resin composition contains a thermosetting resin (A), a coumarin compound (B), and an inorganic filler (C). The thermosetting resin (A) comprises an epoxy resin (A1) and a maleimide resin (A2). The content of maleimide resin (A2) relative to the total amount of the thermosetting resin (A) is 8% by mass or more and 60% by mass or less.

Description

[Technical Field]

[0001] This disclosure generally relates to resin compositions, prepregs, resin-coated films, resin-coated metal foils, metal-clad laminates and printed wiring boards, and more specifically to resin compositions containing epoxy resins, prepregs, resin-coated films, resin-coated metal foils, metal-clad laminates and printed wiring boards. [Previous Technology]

[0002] Printed wiring boards are widely used in various fields such as electronic machines, communication machines, and computers. In recent years, in particular, the multi-functionality, high performance, thinness, and miniaturization of small machines such as recording media, portable communication terminals, and notebook PCs have progressed rapidly. Consequently, printed wiring boards used in these products are also pursuing high performance in terms of conductor wiring miniaturization, high density, multi-layer conductor wiring, thinness, and mechanical properties.

[0003] As a material for the printed wiring board, Patent Document 1 discloses a resin composition. This resin composition contains an epoxy compound, a maleimide compound having an N-phenylmaleimide structure, a phenolic compound, a core and outer shell rubber, and an inorganic filler. The content of the maleimide compound is in the range of 10 parts by mass or more and less than 40 parts by mass relative to a total of 100 parts by mass of the epoxy compound, maleimide compound, and phenolic compound.

[0004] However, the cured resin composition described in Patent Document 1 has a high glass transfer temperature and good resistance to slag removal, but it easily reflects light in the 365nm to 405nm wavelength range, which is the main wavelength region of metal halide lamps or UV LED light sources used for curing general UV-curable resins. That is, light in this wavelength range is reflected and scattered on the surface of the cured material. Therefore, for solder resist formed on a printed circuit board having an insulating layer containing the cured material, undesirable reactions may occur due to the reflection and scattering of light in this wavelength range on the surface of the insulating layer. In other words, the solder resist reaction caused by exposure to light in this wavelength range cannot be controlled. Accordingly, when forming solder resist on a printed circuit board manufactured using the above resin composition, and forming an opening by exposing and developing the solder resist with light in this wavelength range, the smaller the inner diameter of the opening, the worse its shape may be. That is, there may be a problem with poor small-diameter opening performance. Previous Art Documents

[0005] Patent Document Patent Document 1: International Publication No. 2020 / 121734 [Summary of the Invention]

[0006] The purpose of this 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 that has a high glass transfer temperature, good descaling resistance, and good small-diameter opening properties for solder resist forming on a printed wiring board containing the aforementioned cured material.

[0007] The resin composition disclosed herein contains a thermosetting resin (A), a coumarin compound (B), and an inorganic filler (C). The aforementioned thermosetting resin (A) comprises an epoxy resin (A1) and a maleimide resin (A2). The content of the aforementioned maleimide resin (A2) relative to the total amount of the aforementioned thermosetting resin (A) is 8% by mass or more and 60% by mass or less.

[0008] The prepreg disclosed herein comprises at least one of the aforementioned resin composition and the semi-cured form of the aforementioned resin composition; and a fibrous substrate.

[0009] The present invention discloses a resin-attached film comprising: a resin layer comprising at least one of the aforementioned resin composition and a semi-cured form of the aforementioned resin composition; and a support film.

[0010] The present invention discloses a resin-coated metal foil comprising: a resin layer comprising at least one of the aforementioned resin composition and a semi-cured form of the aforementioned resin composition; and a metal foil.

[0011] The metal-clad laminate disclosed herein comprises: an insulating layer comprising a cured form of the aforementioned resin composition; and a metal layer.

[0012] The present invention discloses a metal-clad laminate comprising: an insulating layer comprising a hardened prepreg; and a metal layer.

[0013] The printed wiring board disclosed herein comprises: an insulating layer comprising a hardened form of the aforementioned resin composition; and conductor wiring.

[0014] The present invention discloses a printed wiring board comprising: an insulating layer comprising a hardened prepreg; and conductor wiring.

Implementation Method

[0024] 1. Summary The resin composition of this embodiment contains 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 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).

[0025] As described above, by having the above-mentioned components in the resin composition, the glass transition temperature (Tg) of the cured resin composition will increase.

[0026] Furthermore, by containing the above-mentioned components in the resin composition, the descaling resistance of the cured resin composition will be improved. If the descaling resistance of the cured resin composition is good, deformation of the processing part or peeling of the metal foil in the printed wiring board 5 manufactured using the resin composition can be suppressed, thereby suppressing the reduction of conductor reliability in the printed wiring board 5 manufactured using the resin composition.

[0027] Furthermore, by including the aforementioned components in the resin composition, the small-diameter opening properties of the solder resist (SR) 8 formed on the printed circuit board 5 manufactured using the resin composition are improved (see Figure 7). That is, since the reflectivity of the cured resin composition for light with wavelengths of 365 nm and above to 405 nm is 20% or less, the small-diameter opening properties of the solder resist 8 formed on the printed circuit board 5 manufactured using the resin composition are improved. Specifically, the solder resist 8 is first formed on the printed circuit board 5 manufactured using the resin composition. The formed solder resist 8 is exposed to irradiation light in the wavelength range of 365 nm and above to 405 nm through a photomask, causing the desired portion of the solder resist 8 to react. Here, the insulating layer 50 of the printed circuit board 5 manufactured using the resin composition can suppress the reflection and scattering of irradiation light in that wavelength range reaching its surface. Therefore, the reaction of the undesired portion of the solder resist 8 formed on the printed circuit board 5 can be suppressed or prevented. Subsequently, the solder mask 8 can be shaped into the desired form using a developer. That is, the good small-diameter aperture properties of the solder mask 8 mean that the removal of the solder mask 8 can be carried out more precisely and accurately. In other words, by using this resin composition to manufacture the printed wiring board 5, it is possible to achieve miniaturization and high density of the conductor wiring 51 on the printed wiring board 5.

[0028] Furthermore, the solder resist 8 may use materials with known compositions, such as epoxy resin, polyimide resin, polyphenylene ether resin, aromatic polyene resin, etc. In addition, a negative solder resist is one that reacts in the light-irradiated part but does not dissolve in the developer; a positive solder resist is one that reacts in the light-irradiated part but dissolves in the developer.

[0029] Furthermore, in this disclosure, small-diameter aperture quality means that the aperture portion 7 formed on the solder mask 8 by exposure and development using irradiation light in that wavelength region has a good shape. Also, small diameter refers to a roughly circular shape with a diameter of 100µm or less.

[0030] That is, according to this embodiment, a resin composition with high glass transfer temperature, good descaling resistance, and good small-diameter opening of solder resist 8 formed on a printed wiring board 5 made of 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. We believe that by using at least one of the resin composition, the prepreg 1, the resin-coated film 2, the resin-coated metal foil 3, and the metal-clad laminate 4 to manufacture the printed wiring board 5, it is beneficial to miniaturize and increase the density of the conductor wiring 51 on the surface of the printed wiring board 5. 2. Detailed contents (1) Resin composition

[0031] The resin composition of this embodiment can be used, for example, as a material for a prepreg 1, a material for a resin-coated film 2, a material for a resin-coated metal foil 3, a material for a metal-coated laminate 4, a material for a printed wiring board 5, etc.

[0032] 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) includes an epoxy resin (A1) and a maleimide resin (A2).

[0033] The glass transition temperature of the cured resin composition is 200°C or higher. In this case, the cured resin composition has a high glass transition temperature and can exhibit excellent heat resistance. The aforementioned glass transition temperature is preferably 210°C or higher, and more preferably 220°C or higher. Furthermore, the upper limit of the aforementioned glass transition temperature is, for example, 400°C or lower, but there is no particular limitation.

[0034] The resin composition is adjusted, for example, in the following manner: a thermosetting resin (A) containing epoxy resin (A1) and maleimide resin (A2), a coumarin compound (B) and an inorganic filler (C) are blended, diluted with a suitable solvent, and then stirred and mixed to homogenize it.

[0035] The following describes the composition of the resin composition. Furthermore, in this disclosure, parts by mass and percentage by mass refer only to the mass of each component, excluding the mass of the solvent. (1.1) Composition of the resin composition <Thermosetting resin (A)>

[0036] The resin composition as described above contains a thermosetting resin (A). The thermosetting resin (A) contains a thermosetting compound. When heated, the thermosetting compound undergoes a polymerization reaction, causing the molecular chains to cross-link and form a three-dimensional polymer network structure, thus hardening.

[0037] The thermosetting resin (A) comprises epoxy resin (A1) and maleimide resin (A2). Furthermore, the thermosetting resin (A) may also comprise thermosetting compounds other than epoxy resin (A1) and maleimide resin (A2). Specifically, phenolic resin (A3) may be an example of such thermosetting compound. Moreover, the thermosetting resin (A) may further comprise thermosetting compounds other than epoxy resin (A1), maleimide resin (A2), and phenolic resin (A3). Examples of such thermosetting compounds include, for example, benzo[a]pyrene resin, polyphenylene ether resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, polysiloxane resin, polyurethane resin, polyimide resin, acrylic resin, methacrylic resin, etc., but there are no particular limitations. The thermosetting resin (A) contained in the resin composition may be only one type or may be two or more types. ≪Epoxy Resin (A1)≫

[0038] The thermosetting resin (A) includes epoxy resin (A1) as described above. Epoxy resin (A1) is a component that can improve the glass transition temperature, adhesion to metals and glass, heat resistance, electrical insulation, flame retardancy, etc. of the cured resin composition.

[0039] Epoxy resin (A1) is a compound having one or more epoxy groups in a molecule. Epoxy resin (A1) can be solid or liquid at 25°C.

[0040] Examples of epoxy resin (A1) include: bisphenol type epoxy resin, phenolic varnish type epoxy resin, biphenyl type epoxy resin, alkylene type epoxy resin, arylalkylene type epoxy resin, naphthalene type epoxy resin, naphthalene skeleton modified epoxy resin, triphenylmethane type epoxy resin, anthracene type epoxy resin, dicyclopentadiene type epoxy resin, norphenene type epoxy resin, stilbene type epoxy resin, and phosphorus-containing epoxy resins in which phosphorus atoms are introduced into the above epoxy resins, etc., but there is no particular limitation. The thermosetting resin (A) may contain only one type of epoxy resin (A1) or two or more types.

[0041] Examples of bisphenol type epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, etc., but there are no particular limitations.

[0042] Examples of phenolic varnish type epoxy resins include: phenolic varnish type epoxy resin, cresol varnish type epoxy resin, etc., but there are no particular limitations.

[0043] Examples of arylalkyl epoxy resins include: phenol arylalkyl epoxy resin, biphenyl arylalkyl epoxy resin, biphenyl phenolic varnish epoxy resin, biphenyl dimethyl epoxy resin, triphenol phenolic varnish epoxy resin, tetramethyl biphenyl epoxy resin, etc., but there are no particular limitations.

[0044] Examples of naphthalene skeleton modified epoxy resins include: naphthalene skeleton modified cresol phenolic varnish type epoxy resin, naphthalene glycol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, methoxynaphthalene modified cresol phenolic varnish type epoxy resin, methoxynaphthalene dimethylene type epoxy resin, etc., but there are no particular limitations.

[0045] Furthermore, epoxy resins (A1) are not necessarily classified into only one type. For example, biphenyl alkyl type epoxy resins can be classified not only as arylalkyl type epoxy resins, but also as biphenyl type epoxy resins.

[0046] The epoxy resin (A1) preferably includes 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 resin composition can be improved. Furthermore, the biphenyl-type epoxy resin preferably includes at least one of biphenyl phenolic varnish-type epoxy resins and biphenyl aralkyl-type epoxy resins.

[0047] The content of epoxy resin (A1) relative to the total amount of thermosetting resin (A) should preferably be 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more. In this case, the glass transition temperature, adhesion to metals and glass, heat resistance, flame retardancy, and electrical insulation of the cured resin composition can be improved. Furthermore, the content of epoxy resin (A1) relative to the total amount of thermosetting resin (A) should preferably be 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. In this case, the reduction in adhesion to metals and glass and electrical insulation can be suppressed.

[0048] The epoxy equivalent of the epoxy resin (A1) should preferably be 100 g / eq. or more, and more preferably 150 g / eq. or more. Furthermore, the epoxy equivalent of the epoxy resin (A1) should preferably be 350 g / eq. or less, and more preferably 300 g / eq. or less. ≪Maleimine Resin (A2)≫

[0049] The thermosetting resin (A) includes maleimide resin (A2) as described above. Maleimide resin (A2) is a component that can improve the glass transition temperature, heat resistance, and desizing resistance of the cured resin composition.

[0050] Maleimine resin (A2) is a compound that can react with epoxy resin (A1). Maleimine resin (A2) has one or more maleimine groups in one molecule. Maleimine resin (A2) can be solid or liquid at 25°C.

[0051] The maleimide resin (A2) may contain only a single compound or may contain two or more compounds. Examples of maleimide resin (A2) include monofunctional maleimide resins having one maleimide group in the molecule and polyfunctional maleimide resins having two or more maleimide groups, but there are no particular limitations. The maleimide resin (A2) contained in the thermosetting resin (A) may be only one type or may be two or more types.

[0052] Examples of monofunctional maleimide resins having one maleimide group in the molecule include: chlorophenyl maleimide such as o-chlorophenyl maleimide, methylphenyl maleimide such as o-methylphenyl maleimide, hydroxyphenyl maleimide such as p-hydroxyphenyl maleimide, carboxyphenyl maleimide such as p-carboxyphenyl maleimide, N-dodecyl maleimide, phenylmethane maleimide, etc., but there are no particular limitations.

[0053] Examples of multifunctional maleimide resins having two or more maleimide groups in the molecule include: 4,4'-diphenylmethane bismaleimide, bisphenol A bis(4-maleimide phenyl ether), 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, and 4-methyl-1,3-epenylphenyl bismaleimide. 1,6-bismaleimide-(2,2,4-trimethyl)hexane, 4,4'-diphenyl ether bismaleimide, 4,4'-diphenyl monazine bismaleimide, 1,3-bis(3-maleimide phenoxy)benzene, 1,3-bis(4-maleimide phenoxy)benzene, polyphenylmethane maleimide, polyphenylmethane maleimide, etc., but without particular limitation.

[0054] The maleimide resin (A2) preferably contains at least polyphenylmethane maleimide. In this case, the glass transition temperature and heat resistance of the cured resin composition can be improved.

[0055] The content of maleimide resin (A2) relative to the total amount of thermosetting resin (A) is 8% by mass or more, preferably 15% by mass or more, and more preferably 25% by mass or more. In this case, the glass transition temperature of the cured resin composition can be increased. Furthermore, the content of maleimide resin (A2) relative to the total amount of thermosetting resin (A) is 60% by mass or less, preferably 55% by mass or less, and more preferably 45% by mass or less. In this case, the reduction in the desizing resistance of the cured resin composition can be suppressed.

[0056] The mass ratio of epoxy resin (A1) to 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. Under these conditions, the glass transition temperature and heat resistance of the cured resin composition can be increased, and the reduction in desizing resistance can be suppressed. ≪Phenolic resin (A3)≫

[0057] The thermosetting resin (A) may also include phenolic resin (A3). Phenolic resin (A3) is a component that can improve the glass transition temperature, heat resistance, etc. of the cured resin composition.

[0058] Phenolic resin (A3) can react with epoxy resin (A1) and maleimide resin (A2). Phenolic resin (A3) has phenolic hydroxyl groups in its molecule. Phenolic resin (A3) can be solid or liquid at 25°C.

[0059] Examples of phenolic resins (A3) include: biphenyl aryl phenolic resins, phenyl aryl phenolic resins, phenolic varnish-type phenolic resins, cresol phenolic varnish-type phenolic resins, bisphenol A phenolic varnish-type phenolic resins, naphthol-type phenolic resins, tetraphenol-type phenolic resins, and phosphorus-containing phenolic resins in which phosphorus atoms are introduced, but there are no particular limitations. The thermosetting resin (A) may contain only one type of phenolic resin (A3) or two or more types.

[0060] The phenolic resin (A3) preferably includes at least one of a naphthyl phenolic resin and a biphenyl phenolic resin. In this case, the glass transition temperature and heat resistance of the cured resin composition can be improved.

[0061] The content of phenolic resin (A3) relative to the total amount of thermosetting resin (A) should preferably be 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more. In this case, the glass transition temperature and heat resistance of the cured resin composition can be improved. Furthermore, the content of phenolic resin (A3) relative to the total amount of thermosetting resin (A) should preferably be 65% by mass or less, more preferably 55% by mass or less, and even more preferably 45% by mass or less. In this case, the reduction of brittleness of the cured resin composition can be suppressed.

[0062] The phenolic hydroxyl equivalent of the phenolic resin (A3) should preferably be 100 g / eq. or more, and more preferably 120 g / eq. or more. Furthermore, the phenolic hydroxyl equivalent of the phenolic resin (A3) should preferably be 650 g / eq. or less, and more preferably 600 g / eq. or less.

[0063] When the thermosetting resin (A) contains phenolic resin (A3), the mass ratio of epoxy resin (A1) to phenolic resin (A3) is preferably 5:1 to 1:2, and more preferably 5:2 to 2:3. In this case, the glass transition temperature and heat resistance of the cured resin composition can be improved. <Coumarin compound (B)>

[0064] The resin composition as described above contains coumarin compound (B). Coumarin compound (B) has a coumarin skeleton. The coumarin skeleton is an aromatic compound formed by the condensation of a lactone ring and an aromatic ring. Since coumarin compound (B) has good absorbance for irradiation light in the above-mentioned wavelength region, the reflectivity of the cured resin composition for light with wavelengths above 365 nm and below 405 nm can be reduced.

[0065] The coumarin compound (B) preferably comprises at least one of the following formulas (1) and (2): [Chemical Formula 1][Chemical Formula 2]

[0066] In formulas (1) and (2), R1 and R2 independently represent hydrogen atoms, alkyl groups, aryl groups, or hydroxyalkyl groups, respectively. R3, R4, and R5 independently represent hydrogen atoms, alkyl groups, or aryl groups, respectively. Furthermore, there is no particular limitation on the number of carbon atoms in alkyl and hydroxyalkyl groups. Also, alkyl and hydroxyalkyl groups can be straight-chain or branched, and the number of carbon atoms can be, for example, 8 or less, but there is no particular limitation. R1 to R5 can also be bonded to other substituents to form a ring structure.

[0067] Examples of coumarin compounds (B1) include coumarin, 4-methylcoumarin, 7-amino-4-methylcoumarin, etc., but there are no particular limitations. The resin composition may contain only one or more coumarin compounds (B1).

[0068] The absorbance and absorption wavelength of coumarin compound (B) can be changed by introducing substituents. For example, by introducing an electron-donating group into the 7-position of coumarin compound (B), the electron-donating group and the electron-withdrawing group will coexist in the molecule of coumarin compound (B) and generate charge transfer within the molecule, thus resulting in greater absorbance.

[0069] The absorbance of coumarin compound (B) depends on the number of molecules. The more molecules there are, that is, the larger the mole number of the molecules, the greater the absorbance.

[0070] The content of coumarin compound (B) is preferably 0.1% by mass or more, more preferably 1.5% by mass or more, and more preferably 2.0% by mass or more, relative to the total amount of thermosetting resin (A) and coumarin compound (B). In this case, the reflectivity of the cured resin composition at wavelengths of 365 nm or more and 405 nm or less can be reduced. Furthermore, the content of coumarin compound (B) is preferably 10% by mass or less, more preferably 9% by mass or less, and more preferably 8% by mass or less, relative to the total amount of thermosetting resin (A) and coumarin compound (B). In this case, the decrease in the glass transition temperature of the cured resin composition can be suppressed. <Inorganic filler (C)>

[0071] The resin composition as described above contains inorganic filler (C). Inorganic filler (C) can reduce the coefficient of thermal expansion of the cured resin composition.

[0072] Inorganic filler (C) may include, for example, fused silica or crystalline silica, talc, boehmite, magnesium hydroxide, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, clay, mica, etc., but is not particularly limited. The resin composition may contain only one type of inorganic filler (C) or two or more types.

[0073] The inorganic filler (C) preferably includes at least one filler selected from the group consisting of silica, talc, boehmite, magnesium hydroxide, and aluminum hydroxide. In this case, the coefficient of thermal expansion of the cured resin composition can be reduced.

[0074] In order to improve the affinity with thermosetting resins (A) and prevent aggregation, the inorganic filler (C) may also be surface-treated. Examples of surface treatments include: aminosilane treatment, mercaptosilane treatment, alkoxysilane treatment, etc., but there are no particular limitations.

[0075] The average particle size (D50) of the inorganic filler (C) should preferably be 0.1 µm or more. Furthermore, the average particle size of the inorganic filler (C) should preferably be 10 µm or less. Here, in this disclosure, "average particle size" means the particle size that accounts for 50% of the cumulative value in the particle size distribution of the volume reference obtained by laser diffraction scattering method.

[0076] The content of inorganic filler (C) should preferably be 50 parts by mass or more, and more preferably 75 parts by mass or more, relative to 100 parts by mass of the total thermosetting resin (A) and coumarin compound (B). In this case, the coefficient of thermal expansion of the cured resin composition can be reduced. Furthermore, the content of inorganic filler (C) should preferably be 300 parts by mass or less, and more preferably 250 parts by mass or less, relative to 100 parts by mass of the total thermosetting resin (A) and coumarin compound (B). In this case, the reduction in adhesion and crack resistance of the cured resin composition can be suppressed. <Amine compound (D)>

[0077] The resin composition may also contain an amine compound (D) that does not have a coumarin skeleton. Thus, the amine compound (D) is a different compound from the coumarin compound (B1) shown in formula (2). The amine compound (D) has the following function: it acts as a hardener or hardening accelerator in the crosslinking (hardening) reaction of the thermosetting resin (A), thereby assisting the crosslinking reaction.

[0078] Amino compounds (D) can be exemplified by aromatic amine compounds, fatty acid amine compounds, etc.

[0079] Examples of aromatic amine compounds include imidazole compounds such as 2-methylimidazole and 2-ethyl-4-methylimidazole, but there are no particular limitations. Aromatic amine compounds preferably include imidazole compounds.

[0080] Examples of aliphatic amine compounds include, for example, alicyclic amine compounds such as dicyandiamide (DICY), diazabicycloundecene (DBU), and isophorone diamine (IPDA), and chain aliphatic amine compounds such as diethylenetriamine (DTA) and triethylenetriamine (TTA), but there are no particular limitations. Aliphatic amine compounds preferably include dicyandiamide.

[0081] The amine compound (D) contained in the resin composition may be only one type or may be two or more types.

[0082] Relative to 100 parts by mass of the thermosetting resin (A) and the coumarin compound (B), the content of the amine compound (D) should preferably be 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. Furthermore, relative to 100 parts by mass of the thermosetting resin (A) and the coumarin compound (B), the content of the amine compound (D) should preferably be 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 7 parts by mass or less. <Core and Outer Shell Rubber (E)>

[0083] The resin composition may also contain core and shell rubber (E). Core and shell rubber (E) can improve glass transition temperature, heat resistance, flame retardancy, impact resistance, etc., and can suppress the decrease in coefficient of thermal expansion and desizing resistance. Core and shell rubber (E) is composed of a filler-like rubber core and a grafted layer covering the core.

[0084] The core preferably comprises at least one selected from the group consisting of polymers of (meth)acrylic acid, polymers of (meth)acrylates, polymers of olefin compounds, polybutadiene, and polysiloxane. The outer shell preferably comprises at least one selected from the group consisting of styrene-acrylonitrile copolymers, polymers of (meth)acrylic acid, polybutadiene, and polysiloxane. An example of the core and outer shell rubber (E) is a polysiloxane-acrylic acid composite rubber. The polysiloxane-acrylic acid composite rubber has a core of polysiloxane / acrylic acid polymer and an outer shell of styrene-acrylonitrile copolymer. Furthermore, in this disclosure, "(meth)acrylic acid" means at least one of acrylic acid and methacrylic acid. The core and outer shell rubber (E) contained in the resin composition may be only one type or may be two or more types.

[0085] The core shell rubber (E) can be commercially available. Examples of commercially available products include: products manufactured by Mitsubishi Chemical Co. under the brands "S-2001", "S-2006", "S-2501", "S-2030", "S-2100", "S-2130", "S-2200", "SRK200A", "SX-006", and "SX-005"; products manufactured by Aica Kogyo Co., Ltd. under the brands "AC3816", "AC3816N", "AC3832", "AC4030", "AC3364", and "IM101"; products manufactured by KANEKA CORPORATION under the brands "MX-153", "MX-257", "MX-154", "MX-960", "MX-136", "MX-965", "MX-217", and "MR-01"; and Dow The product names are "EXL-2655", "TMS-2670J", and "TMS-2670S" manufactured by Chemical Japan Limited; and "R-170S", "R-180S", and "R-200" manufactured by Nissin Chemical Industry Co., Ltd., but there are no special restrictions.

[0086] The average particle size of the core and outer shell rubber (E) is, for example, 0.001µm or more and 1µm or less. The average particle size is preferably 0.5µm or less.

[0087] The content of the core and outer shell rubber (E) should preferably be 10% by mass or more, and more preferably 17.5% by mass or more, relative to the total amount of resin components in the resin composition. Furthermore, the content of the core and outer shell rubber (E) should preferably be 50% by mass or less, and more preferably 40% by mass or less, relative to the total amount of resin components in the resin composition. In addition, in this disclosure, "resin components" means components other than inorganic fillers (C) among the non-volatile components of the resin composition. <Additives>

[0088] As long as the additives do not impair the effect of this embodiment, there are no particular limitations on their composition and content.

[0089] Examples of additives include, for example, hardeners and hardening accelerators other than amine compounds (D), thermoplastic resins, flame retardants, colorants, coupling agents, heat stabilizers, antioxidants, reaction initiators, defoamers, antistatic agents, dyes, pigments, polymerization inhibitors, lubricants, etc., but there are no particular limitations.

[0090] Curing agents and curing accelerators other than amine compounds (D) can include, for example, acid anhydrides, cyanate compounds, triphenylphosphine, thiols, metal soaps, and other organic acid metal salts. (1.2) Methods for preparing resin compositions

[0091] Methods for preparing the resin composition may include, for example, mixing epoxy resin (A1) as a thermosetting resin (A), maleimide resin (A2), coumarin compound (B), and inorganic filler (C) in a predetermined amount, but there are no particular limitations. Furthermore, phenolic resin (A3), amine compound (D), core and shell rubber (E), and additives may be added as needed and mixed.

[0092] Furthermore, the resin composition may also contain organic solvents. That is, the resin composition should preferably be used in the form of a varnish-like resin composition containing organic solvents. In addition, a varnish-like resin composition refers to one in which organic solvents are further added in addition to the components contained in the above-mentioned resin composition.

[0093] The resin composition in the varnish state described above is prepared in the following manner. First, the components of the resin composition that are soluble in organic solvents are added to an organic solvent and stirred to mix them, thereby preparing a mixture. Alternatively, the mixture can be prepared by stirring while heating. Next, the components that are insoluble in organic solvents are added to the mixture and dispersed using a ball mill, bead mill, or planetary mixer until the desired dispersion state is achieved, thereby preparing the resin composition in the varnish state. Furthermore, there are no particular limitations on the organic solvent used here, but it is preferable to use one that can dissolve thermosetting resins (A), coumarin compounds (B), etc., without hindering the curing reaction of the resin composition. Examples of organic solvents include toluene and methyl ethyl ketone (MEK), but there are no particular limitations. (2) Application examples of resin compositions

[0094] An application example of the resin composition will be described with reference to Figures 1 to 6.

[0095] By using resin components, a prepreg 1, a resin-coated film 2, a resin-coated metal foil 3, a metal-coated laminate 4, and a printed wiring board 5 can be obtained.

[0096] More specifically, the resin layer 10 of the prepreg 1 includes at least one of a resin composition and a semi-cured form of the resin composition. The resin layer 20 of the resin-coated film 2 includes at least one of a resin composition and a semi-cured form of the resin composition. The resin layer 30 of the resin-coated metal foil 3 includes at least one of a resin composition and a semi-cured form of the resin composition. The insulating layer 40 of the metal-clad laminate 4 includes a cured form of the resin composition. The insulating layer 50 of the printed wiring board 5 includes a cured form of the resin composition.

[0097] In this embodiment, the resin composition is an uncured material, which is soluble and fusible in a certain liquid in its initial stage. That is, the uncured resin composition is in stage A.

[0098] Furthermore, in this embodiment, a semi-cured material refers to a resin composition that has been cured to a point where it can be further cured. For example, when the resin composition of this embodiment is heated, its viscosity will slowly decrease at the beginning of heating, but as the resin composition begins to harden, its viscosity will slowly increase. Thus, a semi-cured material is a resin composition in a semi-cured state, that is, a resin composition that has undergone stage B curing. (2.1) Prepreg

[0099] Figure 1 shows an example of the prepreg 1 of this embodiment. The prepreg 1 is integrally in the form of a film or sheet. The prepreg 1 can be used to manufacture metal-clad laminate 4 and printed wiring board 5. Specifically, the prepreg 1 can be used as a material for metal-clad laminate 4, a material for printed wiring board 5, and for multilayering (addition layering) of printed wiring board 5, etc.

[0100] The prepreg 1 comprises at least one of a resin composition and a semi-cured form of the resin composition. Furthermore, as shown in FIG1, the prepreg 1 may also include a resin layer 10. That is, the resin layer 10 comprises at least one of a resin composition and a semi-cured form of the resin composition. The resin layer 10 further comprises a fibrous substrate 11. That is, the prepreg 1 may also include a resin layer 10, which comprises at least one of a resin composition and a semi-cured form of the resin composition within the fibrous substrate 11.

[0101] Furthermore, the prepreg 1 obtained using the resin composition, as described above, may be a semi-cured material containing the resin composition, or it may be a material containing an uncured resin composition, i.e., an uncured material containing the resin composition.

[0102] As described above, the prepreg 1 may also include a resin layer 10, which is at least one of a resin composition and a semi-cured form of the resin composition impregnated in the fibrous substrate 11. When impregnating at least one of the resin composition and the semi-cured form of the resin composition into the fibrous substrate 11, a varnish made of the resin composition is preferably used.

[0103] As shown in Figure 1, the prepreg 1 has one fibrous substrate 11, but may also have two or more fibrous substrates 11.

[0104] The fibrous substrate 11 is a reinforcing material, and examples include: glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, lint paper, etc., but there are no particular limitations. In particular, by using glass cloth, laminates with excellent mechanical strength can be obtained. There are no particular limitations on the type of glass used in the glass cloth, and examples include E glass, S glass, Q glass, T glass, TS glass, NE glass, and L glass. Furthermore, when the prepreg 1 uses glass cloth as the fibrous substrate 11, the prepreg 1 can achieve the effect of this invention without being affected by the type of glass cloth. The glass cloth should preferably be flattened. The flattening process can specifically be a method of continuously pressing the glass cloth with a pressure roller under appropriate pressure to compress the yarn into a flat shape. In addition, the thickness of the fibrous substrate 11 generally used is, for example, 10µm or more and 180µm or less, but there are no particular limitations. Glass cloth contains glass fibers, but may also contain reinforcing fibers other than glass fibers. The glass cloth may also undergo surface treatment with a coupling agent or the like before being impregnated with the resin composition in a varnish state. Surface treatment improves the adhesion between the glass cloth and the resin composition. Surface treatments may include, for example, treatment of the aforementioned inorganic filler (C), but are not particularly limited.

[0105] The thickness of the prepreg 1 is, for example, in the range of 10µm or more and 200µm or less, but there is no particular limitation.

[0106] Furthermore, to obtain the resin layer 10, the varnish is impregnated into the fibrous substrate 11 by immersing it in varnish or by coating the fibrous substrate 11 with varnish. However, the impregnation can be repeated several times as needed. Also, at this time, the resin layer 10 containing the desired composition and impregnation amount of resin composition or a semi-cured resin composition can be obtained by repeatedly impregnating with several varnishes of different compositions and concentrations.

[0107] Furthermore, regarding the method of manufacturing the prepreg 1, for example, the resin layer 10 may be heated to reduce or remove the organic solvent from the resin layer 10, which is manufactured by impregnating the fibrous substrate 11 with a varnish containing resin components and organic solvent. The conditions for heating the resin layer 10 to reduce or remove the organic solvent from the resin layer 10 are, for example, a temperature of 80°C or higher and 180°C or lower, and a time of 1 minute or more and 10 minutes or less.

[0108] Furthermore, the method for manufacturing at least one of the resin composition of this embodiment and the semi-cured resin composition and the prepreg 1 of the fibrous substrate 11 is not limited to the method described above. That is, the prepreg 1 manufactured using the resin composition of this embodiment can be manufactured by an appropriate method.

[0109] Furthermore, as long as the prepreg 1 is manufactured using a conventional manufacturing method, the surface roughness of its cured form will not affect the reflectivity. That is, the reflectivity of the cured form of the prepreg 1 is not affected by the surface roughness, but depends solely on the composition of the resin composition. Therefore, the cured form of the prepreg 1 manufactured using the aforementioned resin composition is not affected by the surface roughness, and the reflectivity of light with wavelengths of 365 nm and above and 405 nm and below can reach 20% or less. The surface roughness of the cured form of the prepreg 1 is, for example, expressed as an arithmetic mean roughness Sa. This arithmetic mean height Sa is not particularly limited, and for example, is 0.01 µm or more and 2 µm or less.

[0110] Since the prepreg 1 of this embodiment is manufactured using the resin composition of this embodiment, it can simultaneously achieve: a glass transition temperature of 200°C or higher for the cured resin composition; good desizing resistance of the cured resin composition; and a reflectivity of 20% or less for light with wavelengths of 365nm or higher and 405nm or lower for the cured resin composition, thereby ensuring good small-diameter opening properties of the solder mask 8 formed on the printed wiring board 5 manufactured using the resin composition. Furthermore, the prepreg 1 of this embodiment is not limited to manufacturing the printed wiring board 5, but can be applied to various other applications.

[0111] In addition, 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. (2.2) Resin-coated film

[0112] Figures 2 and 3 show an example of the resin-coated film 2 of this embodiment. The resin-coated film 2 is integrally in the form of a film or sheet. The resin-coated film 2 can be used for multilayering (addition layering) of the printed circuit board 5, etc.

[0113] The resin-attached film 2 comprises: a resin layer 20, which includes at least one of a resin composition and a semi-cured form of the resin composition; and a support film 21. That is, the resin-attached film 2 comprises: a resin layer 20, which includes at least one of a resin composition and a semi-cured form of the resin composition; and a support film 21, which is laminated with the resin layer 20. Furthermore, the resin-attached film 2 may also have other layers between the resin layer 20 and the support film 21.

[0114] Furthermore, as described above, the resin layer 20 may be a semi-cured material containing a resin composition, or it may be an uncured material containing an uncured resin composition. That is, the resin-attached film 2 may be a resin-attached film 2 having a resin layer 20 containing a semi-cured material containing a resin composition and a supporting film 21, or it may be a resin-attached film 2 having a resin layer 20 containing an uncured material containing a resin composition before curing and a supporting film 21.

[0115] The resin layer 20 may or may not include a fibrous substrate (not shown). Furthermore, when the resin layer 20 includes a fibrous substrate, the fibrous substrate may be the same as the fibrous substrate 11 of the prepreg 1. That is, the resin layer may also be manufactured from the prepreg 1.

[0116] The support film 21 supports the resin layer 20. In this way, the resin layer 20 can be easily disposed of by supporting the resin layer 20 with the support film 21.

[0117] The supporting film 21 may be, for example, an electrically insulating film, but is not particularly limited. Examples of supporting films 21 include: polyethylene terephthalate (PET) film, polyimide film, polyester film, polydiphenyl ether ketone film, polyphenylene sulfide film, polyamide film, polycarbonate film, polyarylate film, etc., but are not particularly limited.

[0118] A release agent layer (not shown) may also be provided on the surface of the support resin layer 20 of the support film 21. The support film 21 can be peeled off from the resin layer 20 as needed by means of the release agent layer. It is advisable to allow the resin layer 20 to harden and form an insulating layer before peeling the support film 21 off from the insulating layer.

[0119] In Figure 2, the support film 21 covers one side of the resin layer 20, but it can also be shown in Figure 3, with the film 22 covering the other side of the resin layer 20. By covering both sides of the resin layer 20, the resin layer 20 can be handled more easily, and foreign matter can be prevented from adhering to the resin layer 20.

[0120] The cover film 22 may be, for example, an electrically insulating film, but is not particularly limited thereto. Examples of cover film 22 include polyethylene terephthalate (PET) film, polyolefin film, polyester film, polymethylpentene film, etc., but are not particularly limited thereto. Furthermore, a release agent layer (not shown) may be provided between the resin layer 20 and the cover film 22. With the release agent layer, the cover film 22 can be peeled off from the resin layer 20 as needed.

[0121] In addition, the support film 21 and the cover film 22 may also be surface treated as required, such as matte treatment, corona treatment, demolding treatment or roughening treatment.

[0122] The thickness of the resin layer 20 is not particularly limited, but it is preferably 120µm or less, more preferably 100µm or less, even more preferably 60µm or less, and even more preferably 40µm or less. This allows for a thinner printed wiring board 5 by reducing the thickness of the insulating layer. Furthermore, the thickness of the resin layer is preferably 10µm or more.

[0123] The resin layer 20 is manufactured by coating a resin composition onto the support film 21. The coating method for the resin composition may include, for example, using a bar coater, a die coater, a doctor blade, or a baker applicator, but is not particularly limited. When coating the resin layer 20 onto the support film 21, a resin composition in a varnish state is preferable. As mentioned above, by heating the varnish already coated on the support film 21, the organic solvent can be evaporated from the varnish, reducing or removing the organic solvent. The coated varnish can be heated, for example, at a temperature of 80°C or higher and 180°C or lower, for a time of 1 minute or more and 10 minutes or less. That is, the conditions under which the resin layer 20 is heated to reduce or remove the organic solvent from the resin layer 20 can also be performed under the same conditions as when the resin layer 10 is heated to reduce or remove the organic solvent from the resin layer 10 during the manufacture of the prepreg 1. By forming a resin layer 20 containing at least one of a resin composition and a semi-cured resin composition on a support film 21 in the manner described above, a resin-coated film 2 can be manufactured.

[0124] Furthermore, the method for manufacturing a resin-attached film 2 comprising a resin layer 20 including the resin composition of this embodiment or a semi-cured resin composition and a support film 21 supporting the resin layer 20 is not limited to the method described above. That is, the resin-attached film 2 manufactured using the resin composition of this embodiment can be manufactured by an appropriate method.

[0125] Furthermore, as long as the resin-coated film 2 is manufactured using a conventional manufacturing method, the surface roughness of the hardened resin layer 20 will not affect the reflectivity. That is, the reflectivity of the hardened resin layer 20 is not affected by the surface roughness, but depends solely on the composition of the resin composition. Therefore, the hardened resin layer 20 manufactured using the aforementioned resin composition is not affected by surface roughness, and the reflectivity of light with wavelengths of 365 nm and above and 405 nm and below can reach 20% or less. The surface roughness of the hardened resin layer 20 is, for example, expressed as an arithmetic mean roughness Sa. This arithmetic mean height Sa is not particularly limited, for example, being 0.01 µm or more and 2 µm or less.

[0126] Since the resin layer 20 of the resin-coated film 2 of this embodiment is manufactured using the resin composition of this embodiment, it can simultaneously achieve: a glass transition temperature of 200°C or higher for the cured resin composition; good descaling resistance of the cured resin composition; and a reflectivity of 20% or less for light with wavelengths of 365nm or higher and 405nm or lower, thereby ensuring good small-diameter opening properties of the solder mask 8 formed on the printed wiring board 5 manufactured using the resin composition. Furthermore, the resin-coated film 2 of this embodiment is not limited to manufacturing the printed wiring board 5, but can be applied to various other applications. (2.3) Resin-coated metal foil

[0127] Figure 4 shows an example of the resin-coated metal foil 3 of this embodiment. The resin-coated metal foil 3 is integrally in the form of a thin film or sheet. The resin-coated metal foil 3 can be used for multilayering (addition layering) of printed wiring boards 5, etc.

[0128] The resin-coated metal foil 3 comprises: a resin layer 30, which includes at least one of a resin composition and a semi-cured form of the resin composition; and a metal foil 31. Furthermore, the resin-coated metal foil 3 may also have other layers between the resin layer 30 and the metal foil 31.

[0129] As described above, the resin layer 30 may be a semi-cured material containing a resin composition, or it may be an uncured material containing an uncured resin composition. That is, the resin-attached metal foil 3 may be a resin-attached metal foil 3 having a resin layer 30 containing a semi-cured material containing a resin composition and a metal foil 31, or it may be a resin-attached metal foil 3 having a resin layer 30 containing an uncured material containing a resin composition before curing and a metal foil 31.

[0130] The resin layer 30 may or may not include a fibrous substrate (not shown). Furthermore, when the resin layer 30 includes a fibrous substrate, the fibrous substrate may be the same as the fibrous substrate 11 of the prepreg 1. That is, the resin layer 30 may be manufactured from the prepreg 1.

[0131] The metal foil 31 can be, for example, copper foil, aluminum foil, etc., but is not particularly limited. The metal foil 31 can be used to make conductor wiring 51 of the printed wiring board 5 by etching away the unwanted parts using a subtractive process or the like.

[0132] Furthermore, the resin-coated metal foil 3 may also be equipped with a covering film (not shown) or the like, as needed. The covering film may be the same material used in the resin-coated film 2 described above.

[0133] The resin layer 30 is manufactured by coating a resin composition onto the metal foil 31. The coating method for the resin composition may include, for example, using a bar coater, a die coater, a doctor blade, or a Beck coater, but there are no particular limitations. When coating the resin composition onto the metal foil 31, a resin composition in a varnish-like state is preferable.

[0134] As described above, by heating the varnish already coated on the metal foil 31, the organic solvent can be evaporated from the varnish, thereby reducing or removing the organic solvent. The coated varnish can be heated, for example, at a temperature of 80°C or higher and 180°C or lower, for a time of 1 minute or more and 10 minutes or less. That is, the conditions under which the resin layer 30 is heated to reduce or remove the organic solvent from the resin layer 30 can also be performed under the same conditions as when the resin layer 10 is heated to reduce or remove the organic solvent from the resin layer 10 during the preparation of the prepreg 1.

[0135] Furthermore, the method for manufacturing a resin-coated metal foil 3 comprising a resin composition of this embodiment or a semi-cured resin composition and a metal foil 31 adhered to the resin layer 30 is not limited to the method described above. That is, the resin-coated metal foil 3 manufactured using the resin composition of this embodiment can be manufactured by an appropriate method.

[0136] Furthermore, as long as the resin-coated metal foil 3 is manufactured using a conventional manufacturing method, the surface roughness of the hardened resin layer 30 will not affect the reflectivity. That is, the reflectivity of the hardened resin layer 30 is not affected by the surface roughness, but depends solely on the composition of the resin composition. Therefore, the hardened resin layer 30 manufactured using the aforementioned resin composition is not affected by surface roughness, and the reflectivity of light with wavelengths of 365 nm and above and 405 nm and below can reach 20% or less. The surface roughness of the hardened resin layer 30 is, for example, expressed as an arithmetic mean roughness Sa. This arithmetic mean height Sa is not particularly limited, for example, being 0.01 µm or more and 2 µm or less.

[0137] Since the resin layer 30 of the resin-coated metal foil 3 in this embodiment is manufactured using the resin composition of this embodiment, it can simultaneously achieve: a glass transition temperature of 200°C or higher for the cured resin composition; good descaling resistance of the cured resin composition; and a reflectivity of 20% or less for light with wavelengths of 365nm or higher and 405nm or lower, thereby ensuring good small-diameter opening properties of the solder mask 8 formed on the printed wiring board 5 manufactured using the resin composition. Furthermore, the resin-coated metal foil 3 of this embodiment is not limited to the manufacture of printed wiring boards, but can be applied to various other applications. (2.4) Metal-clad laminate

[0138] 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, which contains a cured form of the resin composition of this embodiment; and a metal layer 41, which is laminated with the insulating layer 40. The metal-clad laminate 4 can be used as a material for printed wiring boards 5, etc.

[0139] A method for manufacturing the metal-clad laminate 4 may include, for example, laminating a resin composition or a semi-cured resin composition with a metal layer 41, and then heating and pressurizing the resin composition to harden it into an insulating layer 40, thereby manufacturing the metal-clad laminate 4. More specifically, a metal layer 41 such as copper foil may be laminated to one or both sides of a resin composition or a semi-cured resin composition, and the resin composition or the semi-cured resin composition and the metal layer 41 may be heated and pressurized to harden the resin composition into an insulating layer 40. Then, the insulating layer 40 containing the hardened resin composition and the metal layer 41 may be laminated together to form a metal-clad laminate 4 in which the metal layer 41 is densely attached to one or both sides of the insulating layer 40 containing the hardened resin composition.

[0140] Furthermore, the insulating layer 40 can also be manufactured using the aforementioned prepreg 1. More specifically, the prepreg 1 and the metal layer 41 can be heated and pressed to harden the prepreg 1 and form the insulating layer 40. Then, the insulating layer 40 containing the hardened prepreg 1 and the metal layer 41 are laminated together to form a metal-clad laminate 4 on one or both sides of the insulating layer 40 containing the hardened prepreg 1. When the metal-clad laminate 4 is manufactured using the prepreg 1, as shown in FIG. 5, a fibrous substrate 42 is provided within the insulating layer 40. The fibrous substrate 42 may be a single sheet or two or more sheets.

[0141] Furthermore, the insulating layer 40 can also be manufactured using the aforementioned resin-coated film 2 and resin-coated metal foil 3. 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 can be heated and pressed to harden 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. Then, the insulating layer 40 containing the hardened resin layer 20 of the resin-coated film 2 or the hardened resin layer 30 of the resin-coated metal foil 3 and the metal layer 41 are laminated together to form a metal-clad laminate 4 on one or both sides of the insulating layer 40 containing the hardened resin layer 20 of the resin-coated film 2 or the hardened resin layer 30 of the resin-coated metal foil 3. Here, when the resin-coated metal foil 3 is used for manufacturing, the metal foil 31 of the resin-coated metal foil 3 becomes the metal layer 41 in the metal-clad laminate 4.

[0142] The heating and pressurizing conditions during the manufacture of the metal-clad laminate 4 can be appropriately set according to the thickness of the metal-clad laminate 4 to be manufactured and the type and composition of the resin composition forming the insulating layer 40.

[0143] The heating temperature during the manufacture of the metal-clad laminate 4 is, for example, 200°C or higher and 250°C or lower. Furthermore, the pressure during the manufacture of the metal-clad laminate 4 is, for example, 1 MPa or higher and 5 MPa or lower. Additionally, the heating and pressurizing time during the manufacture of the metal-clad laminate 4 is, for example, 30 minutes or higher and 120 minutes or lower.

[0144] When manufacturing the metal-clad laminate 4, the thickness of the metal layer 41 can be appropriately set according to the desired purpose. The thickness of the metal layer 41 is, for example, 5µm or more and 35µm or less, but there is no particular limitation. When using an extremely thin metal foil as the metal layer 41, in order to improve processability, a carrier-supported metal foil having a release layer and a carrier can also be used.

[0145] Furthermore, the method for manufacturing a metal-clad laminate 4 having an insulating layer 40 comprising a cured material including the resin composition or prepreg 1 of this embodiment and a metal layer 41 adhered to the insulating layer 40 is not limited to the method described above. That is, the metal-clad laminate 4 manufactured using the resin composition or prepreg 1 of this embodiment can be manufactured by any appropriate method.

[0146] Furthermore, as long as the metal-clad laminate 4 is manufactured using a conventional manufacturing method, the surface roughness of the insulating layer 40 will not affect the reflectivity. That is, the reflectivity of the insulating layer 40 is not affected by the surface roughness, but depends solely on the composition of the resin composition. Therefore, the insulating layer 40 manufactured using the aforementioned resin composition is not affected by the surface roughness, and the reflectivity of light with wavelengths of 365 nm and above and 405 nm and below can reach 20% or less. The surface roughness of the insulating layer 40 is, for example, expressed as an arithmetic mean roughness Sa. This arithmetic mean height Sa is not particularly limited, for example, being 0.01 µm or more and 2 µm or less.

[0147] Since the insulating layer 40 of the metal-clad laminate 4 of this embodiment is manufactured using the resin composition or prepreg 1 of this embodiment, it can simultaneously achieve: a glass transition temperature of 200°C or higher for the cured resin composition; good desizing resistance of the cured resin composition; and a reflectivity of 20% or less for light with wavelengths of 365nm or higher and 405nm or lower, thereby ensuring good small-diameter opening properties of the solder mask 8 formed on the printed wiring board 5 manufactured using the resin composition or prepreg 1. Furthermore, the metal-clad laminate 4 of this embodiment is not limited to manufacturing printed wiring boards 5, but can be applied to various other applications. (2.5) Printed Wiring Board

[0148] FIG6 shows an example of a printed wiring board 5 according to this embodiment. The printed wiring board 5 includes: an insulating layer 50, which includes a cured resin composition; and conductor wiring 51, which is laminated with the insulating layer 50. The conductor wiring 51 may be formed on only one side of the insulating layer 50 or on both sides.

[0149] The insulating layer 50 may also include the hardened form of the prepreg 1. That is, the printed wiring board 5 includes: an insulating layer 50, which is manufactured using the prepreg 1; and conductor wiring 51, which is laminated with the insulating layer 50. The conductor wiring 51 may be formed on only one side of the insulating layer 50 or on both sides. When the printed wiring board 5 is manufactured using the prepreg 1, it has a fibrous substrate 52 as shown in FIG. 6. The fibrous substrate 52 may be a single sheet or two or more sheets.

[0150] Furthermore, the printed wiring board 5 can also be manufactured using the aforementioned metal-clad laminate 4. More specifically, the conductor wiring 51 can be formed by etching or other processes on the surface of the metal layer 41 of the metal-clad laminate 4. That is, the printed wiring board 5 can be formed by partially removing the metal layer 41 on the surface of the metal-clad laminate 4. By performing the above-described method, a printed wiring board 5 having an insulating layer 50 and conductor wiring 51 serving as a circuit on one or both sides of the insulating layer 50 can be manufactured.

[0151] In addition to the methods mentioned above, other methods for forming circuits include, for example, forming circuits by the Semi Additive Process (SAP) or the Modified Semi Additive Process (MSAP), but there are no particular limitations.

[0152] Furthermore, as long as the printed wiring board 5 is manufactured using a conventional manufacturing method, the surface roughness of the insulating layer 50 will not affect the reflectivity. That is, the reflectivity of the insulating layer 50 is not affected by the surface roughness, but depends solely on the composition of the resin composition. Therefore, the insulating layer 50 manufactured using the aforementioned resin composition is not affected by the surface roughness, and the reflectivity of light with wavelengths of 365 nm and above and 405 nm and below can reach 20% or less. The surface roughness of the insulating layer 50 is, for example, expressed as an arithmetic mean roughness Sa. This arithmetic mean height Sa is not particularly limited, for example, being 0.01 µm or more and 2 µm or less.

[0153] Since the insulating layer 50 of the printed wiring board 5 of this embodiment is manufactured using the resin composition or prepreg 1 of this embodiment, it can simultaneously achieve: a glass transition temperature of 200°C or higher for the cured resin composition; good descaling resistance of the cured resin composition; and a reflectivity of 20% or less for light with wavelengths of 365nm or higher and 405nm or lower for the cured resin composition, thereby ensuring good small-diameter opening properties of the solder mask 8 formed on the printed wiring board 5 manufactured using the resin composition or prepreg 1. 3. Sample

[0154] As is evident from the above embodiments, this disclosure includes the following forms. Hereinafter, the parentheses around the symbols are only used to explicitly indicate the correspondence with the embodiments.

[0155] The resin composition of the first state sample contains 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); and the content of 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).

[0156] According to this sample, the hardened resin composition has a high glass transition temperature, good desizing resistance, and good small-diameter opening properties of the solder resist (8) formed on the printed wiring board (5) made using the resin composition.

[0157] The second state sample is based on the resin composition of the first state sample. In the second state sample, the coumarin compound (B) includes at least one of the coumarin compounds (B1) shown in formula (1) and formula (2); [Chemical Formula 3][Chemical Formula 4]

[0158] (In formulas (1) and (2), R1 and R2 independently represent hydrogen atoms, alkyl, aryl or hydroxyalkyl, respectively; R3, R4 and R5 independently represent hydrogen atoms, alkyl or aryl, respectively).

[0159] The third state sample is based on the resin composition of the first or second state sample. In the third state sample, the mass ratio of epoxy resin (A1) to maleimide resin (A2) is 10:1 to 2:5.

[0160] The fourth state sample is a resin composition based on any one of the first to third state samples. In the fourth state sample, the epoxy resin (A1) includes at least one selected from the group consisting of biphenyl-type epoxy resin, naphthalene-type epoxy resin and dicyclopentadiene-type epoxy resin.

[0161] The fifth state sample is a resin composition based on any one of the first to fourth state samples. In the fifth state sample, the thermosetting resin (A) further includes a phenolic resin (A3).

[0162] The sixth state sample is a resin composition based on any one of the first to fifth state samples. In the sixth state sample, the content of coumarin compound (B) is 0.4% by mass or more and 10% by mass or less relative to the total amount of thermosetting resin (A) and coumarin compound (B).

[0163] The seventh state sample is a resin composition based on any one of the first to sixth state samples. In the seventh state sample, the content of inorganic filler (C) is 50 parts by mass or more and 300 parts by mass or less, relative to a total of 100 parts by mass of thermosetting resin (A) and coumarin compound (B).

[0164] The eighth state sample is a resin composition based on any one of the first to seventh state samples. In the eighth state sample, the resin composition further contains an amine compound (D) that does not have a coumarin skeleton.

[0165] The 9th state sample is a resin composition based on any one of the 1st to 8th state samples. In the 9th state sample, it further contains a core and outer shell rubber (E).

[0166] The 10th state sample is a resin composition based on any one of the 1st to 9th state samples. In the 10th state sample, the inorganic filler (C) comprises at least one filler selected from the group consisting of silica, talc, boehmite, magnesium hydroxide and aluminum hydroxide.

[0167] The prepreg (1) of the 11th state sample comprises: at least one of the resin composition and the semi-cured resin composition according to any one of the 1st to 10th state samples; and a fibrous substrate (11).

[0168] The resin-attached film (2) of the 12th state sample comprises: a resin layer (20) which includes at least one of the resin composition according to any one of the 1st to 10th state samples and a semi-cured resin composition; and a support film (21).

[0169] The resin-coated metal foil (3) of the 13th state sample comprises: a resin layer (30) comprising at least one of a resin composition according to any one of the 1st to 10th state samples and a semi-cured resin composition; and a metal foil (31).

[0170] The metal-clad laminate (4) of the 14th state sample comprises: an insulating layer (40) comprising a hardened resin composition according to any one of the 1st to 10th state samples; and a metal layer (41).

[0171] The metal-clad laminate (4) of the 15th state sample includes: an insulating layer (40) comprising a hardened material of the prepreg (1) according to the 11th state sample; and a metal layer (41).

[0172] The printed wiring board (5) of the 16th state sample includes: an insulating layer (50) comprising a hardened resin composition according to any one of the 1st to 10th state samples; and conductor wiring (51).

[0173] The printed wiring board (5) of the 17th state sample includes: an insulating layer (50) comprising a hardened material of the prepreg (1) according to the 11th state sample; and conductor wiring (51).

[0174] Examples Hereinafter, the present disclosure will be specifically described by way of examples. However, the present disclosure is not limited to the following examples. (1) Resin composition

[0175] The raw materials for the resin composition are those shown in Tables 1 and 2. Then, thermosetting resin (A), coumarin compound (B), inorganic filler (C), amine compound (D), and core and outer shell rubber (E) are blended in the amounts shown in Tables 1 and 2, diluted with a solvent (methyl ethyl ketone), and stirred and mixed to homogenize, thereby preparing the resin compositions in the varnish state of the examples and comparative examples. Details of each component used are as follows. (1.1) Thermosetting Resins (A) <Epoxy Resins (A1)> -Epoxy Resin #1: Manufactured by DIC Corporation, product name "EPICLON HP-9500", naphthalene-type epoxy resin, epoxy equivalent 220~240g / eq. -Epoxy Resin #2: Manufactured by Nippon Kayaku Co., Ltd., product name "NC-3500", biphenyl-type epoxy resin, epoxy equivalent 209g / eq. -Epoxy Resin #3: Manufactured by Nippon Kayaku Co., Ltd., product name "NC-3000H", biphenyl-type epoxy resin, epoxy equivalent 280~300g / eq. <Maleimine Resin (A2)> -Maleimine Resin #1: Manufactured by Daiwa Kasei Corporation, product name "BMI-2300" -Maleimine Resin #2: Manufactured by Nippon Kayaku Co., Ltd., product name "MIR-3000-70MT". <Phenolic Resins (A3)> -Phenolic Resin #1: Manufactured by Nippon Kayaku Co., Ltd., product name "GPH-103", biphenyl type phenolic resin, phenolic hydroxyl equivalent 231 g / eq. -Phenolic Resin #2: Manufactured by Dow Chemical Japan Limited., product name "XZ92741", phosphorus-containing type phenolic resin, phenolic hydroxyl equivalent 550 g / eq. -Phenolic Resin #3: Manufactured by Meiwa Kasei Co., Ltd., product name "MEHC-7403H", biphenyl type phenolic resin, phenolic hydroxyl equivalent 132 g / eq. (1.2) Coumarin Compounds (B) -Coumarin Compound #1: Manufactured by Tokyo Chemical Industry Co., Ltd., compound name "7-amino-4-methylcoumarin". (1.3) Inorganic filler (C) - Inorganic filler #1: Manufactured by Admatechs Corporation, product name "SC2500-SXJ", aminosilane treated silica, average particle size (D50): 0.5µm. (1.4) Amine compound (D) - Amine compound #1: Manufactured by Shikoku Chemical Industry Co., Ltd., product name "2E4MZ", compound name "2-ethyl-4-methylimidazolium". (1.5) Core and outer shell rubber (E) - Core and outer shell rubber #1: Manufactured by Mitsubishi Chemical Co., product name "SRK200A", core: polysiloxane, outer shell: styrene-acrylonitrile copolymer, average particle size (D50): 0.15µm. (2) Prepreg

[0176] Prepare glass cloth (made by Nitto Boshoku Co., Ltd., #2118 type, WEA2118T-107-S199, E glass) as a fibrous substrate. The glass cloth is a woven fabric composed of approximately orthogonal weaves of warp and weft threads. The resin composition in a clear state is impregnated into the glass cloth such that the thickness of the cured prepreg is 100µm. Using a non-contact heating unit, the resin composition impregnated into the glass cloth is heated and dried at 130°C until it becomes a semi-cured product. The solvent in the resin composition is removed thereby, and a prepreg containing the glass cloth and the semi-cured product of the resin composition impregnated into the glass cloth is obtained. The total mass of the prepreg is 100%, and the content of the resin layer 10 in the prepreg is 46% by mass. (3) Metal-clad laminate

[0177] Two prepregs obtained in the above manner were stacked together to obtain a laminate, and copper foil (manufactured by Mitsui Metals & Mining Co., Ltd., thickness: 12µm, 3EC-VLP-12) was stacked on both sides of the obtained laminate to form a metal layer to obtain a laminate with copper foil attached. The laminate with copper foil attached was heated and pressed to obtain a metal-clad laminate with metal layers on both sides and a thickness of 0.2mm. The heating and pressing conditions were 220°C, 2MPa, and 90 minutes. (4) Test (4.1) Glass transfer temperature

[0178] An unclad board is obtained by etching away the copper foil adhering to both sides of the metal-clad laminate. The unclad board is cut at a 45° angle (oblique) relative to the longitudinal or transverse lines of the glass cloth to obtain a test piece with dimensions of 50mm × 5mm × 0.2mm.

[0179] For this test piece, tanδ was measured using a dynamic viscoelasticity measuring device (manufactured by SII NanoTechnology Inc., "DMS6100") under a heating condition of 5℃ / min (DMA method), and its peak temperature was used as the glass transition temperature. (4.2) Reflectivity

[0180] An unclad board was obtained by etching away the copper foil adhered to both sides of the metal-clad laminate. A test piece of 50 mm × 50 mm × 0.2 mm was obtained from the unclad board.

[0181] For this test piece, an ultraviolet-visible spectrophotometer (manufactured by Shimadzu Corporation, "UV-2500PC") was used to measure the reflectance of light with wavelengths of 365nm, 385nm, 395nm and 405nm in the thickness direction of the test piece. The reflectance was measured using an integrating sphere (integrating sphere inner diameter: Φ60mm, barium sulfate coating type) accessory device, under the conditions of an incident angle of 5° and reflectance measurement mode, to perform relative total light reflectance measurement. (4.3) Solder resist small diameter opening property

[0182] First, an unclad board was obtained by etching away the copper foil attached to a 5cm × 5cm metal-clad laminate. A photosensitive dry film solder resist (manufactured by Taiyo Ink Mfg. Co., Ltd., PSR-800 AUS410, thickness: 20µm, negative) was applied to the entire surface of the unclad board using a vacuum laminator at a lamination temperature of 75°C, a vacuum holding time of 20 seconds, and a pressure time of 60 seconds to obtain a test piece.

[0183] Next, the obtained test piece was exposed to the photomask with an aperture pattern of 100µm or 60µm in diameter using an exposure apparatus equipped with a metal halide lamp (manufactured by ORC Corporation, "HMW-680 GW20") at 20°C and a cumulative irradiation dose of 600mJ / cm2 to harden the dry film solder resist. Furthermore, the unirradiated inner edge portion 6 in Figures 7-9 refers to the inner edge portion of the area that was not irradiated by light of 365nm or higher and 405nm or lower by the photomask.

[0184] After exposure, the test piece was developed by spray development. The development process involved spraying a 1% sodium bicarbonate aqueous solution at 30°C at a spray pressure of 0.2 MPa for 120 seconds. After development, a water wash was performed at 25°C and a spray pressure of 0.1 MPa for 45 seconds. After washing, a post-curing treatment was performed at 150°C for 60 minutes, followed by a post-UV treatment using a high-pressure mercury lamp at 1000 mJ / cm² to harden the dry film solder resist. Furthermore, the post-curing and post-UV treatments further hardened the exposed dry film solder resist. Through these treatments, solder resist 8 was formed on the test piece.

[0185] Then, the inner edge 6 of the un-illuminated portion of the above-mentioned test piece was observed using a scanning electron microscope (SEM), and the observation results were classified according to the following evaluation criteria to evaluate the solder mask opening performance of each test piece. <Evaluation Criteria> S: Solder mask openings with a dot diameter of Φ60µm and Φ100µm have good shape A: Solder mask openings with a dot diameter of Φ100µm have good shape

[0186] B: Poor shape of solder resist opening with a diameter of Φ100µm.

[0187] A good solder mask opening shape, as defined by the evaluation criteria, refers to the following state: for each spot diameter, as shown in Figure 7, there is no residual solder mask 8 inside the inner edge of the unirradiated portion 6, and the opening portion 7 is approximately circular. On the other hand, a poor solder mask opening shape refers to the following state: for a spot diameter of Φ100µm, as shown in Figure 8, there is residual solder mask 8 inside the inner edge of the unirradiated portion 6, and the opening portion 7 is not circular, and only a portion of the inner edge of the unirradiated portion 6 is open; or, as shown in Figure 9, the opening portion 7 cannot be formed, and solder mask 8 remains entirely inside the inner edge of the unirradiated portion 6. Furthermore, evaluation A is the result of a good opening shape for a spot diameter of Φ100µm, but a poor opening shape for a spot diameter of Φ60µm.

[0188] If the evaluation is S or A, the small diameter opening performance of the solder resist is good. (4.4) Descaling resistance

[0189] The descaling resistance is calculated by taking the mass of the test piece before descaling treatment and the mass of the test piece after descaling treatment with permanganate, and evaluating it based on the calculated value.

[0190] Specifically, a test piece is obtained by etching away the copper foil adhered to a 5cm × 5cm metal-clad laminate. The amount of etched adhesive residue is calculated by comparing the mass of the test piece before the desmearing treatment (initial mass) with the mass of the test piece after the desmearing treatment under the following conditions (unit: mg / cm2).

[0191] The initial mass determination of the test pieces before treatment was performed by drying the test pieces at 130°C for 30 minutes and then air-cooling them in a desiccator for 2 hours. The descaling treatment was carried out using the following steps (a) to (d). (a) Swelling step

[0192] First, the test piece before treatment, after initial mass determination, was swelled for 5 minutes with Atotech's "Swelling Dip Securiganth P (500 ml / L)" and sodium hydroxide aqueous solution (40 g / L). (b) Desiccant removal step

[0193] Then, a micro-etching process was performed for 10 minutes using "Concentrate Compact CP (580 ml / L)" manufactured by Atotech and an aqueous solution of sodium hydroxide (40 g / L). (c) Neutralization step

[0194] Next, neutralize with Atotech's "Reduction Solution Securiganth P500 (70 ml / L)" and sulfuric acid (98%, 50 ml / L) for 5 minutes. (d) Drying step

[0195] Finally, dry it at 130°C for 30 minutes.

[0196] Repeat steps (a) to (c) above twice, then perform step (d), and after air cooling in a desiccator for 2 hours, measure the mass of the treated test piece. Calculate the amount of desmearing etching as described above.

[0197] When the amount of etchant removal residue is less than 0.5 mg / cm2, the etchant removal residue resistance is good.

[0198] [Table 1]

[0199] [Table 2] Figure 1 is a schematic cross-sectional view showing a prepreg body of one embodiment of the present disclosure. [Simplified Explanation of the Diagram]

[0016] Figure 2 is a schematic cross-sectional view of a resin-coated film (uncovered film) of one embodiment disclosed herein.

[0017] Figure 3 is a schematic cross-sectional view of the resin-coated film (with a covering film) as described above.

[0018] Figure 4 is a schematic cross-sectional view showing a resin-coated metal foil of one embodiment of the present disclosure.

[0019] Figure 5 is a schematic cross-sectional view of a metal-clad laminate according to an embodiment of the present disclosure.

[0020] Figure 6 is a schematic cross-sectional view of a printed wiring board according to an embodiment of the present disclosure.

[0021] Figure 7 is a schematic diagram showing the results of evaluating S or A in the small-diameter opening performance evaluation criteria of the present disclosure embodiment.

[0022] Figure 8 is a schematic diagram showing an example of the results of evaluation B in the small-diameter opening performance evaluation criterion of the present disclosure embodiment.

[0023] Figure 9 is a schematic diagram showing an example of the results of evaluation B in the small-diameter opening performance evaluation criterion of the present disclosure embodiment.

Claims

1. A resin composition for an insulating layer, 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) relative to the total amount of the thermosetting resin (A) is 8% by mass or more and 60% by mass or less; and the content of the coumarin compound (B) relative to the total amount of the thermosetting resin (A) and the coumarin compound (B) is 0.4% by mass or more and 10% by mass or less.

2. The resin composition for the insulating layer of claim 1, wherein the aforementioned coumarin compound (B) comprises at least one of the coumarin compounds (B1) of formula (1) and formula (2); [Chemical Formula 1] [Chemical Formula 2] (in formula (1) and formula (2), R1 and R2 independently represent hydrogen atoms, alkyl, aryl or hydroxyalkyl, respectively; R3, R4 and R5 independently represent hydrogen atoms, alkyl or aryl, respectively).

3. The resin composition for the insulating layer as claimed in claim 1, wherein the mass ratio of the aforementioned epoxy resin (A1) to the aforementioned maleimide resin (A2) is 10:1 to 2:

5.

4. The resin composition for the insulating layer as claimed in claim 1, wherein the aforementioned epoxy resin (A1) comprises at least one selected from the group consisting of biphenyl-type epoxy resin, naphthalene-type epoxy resin and dicyclopentadiene-type epoxy resin.

5. The resin composition for the insulating layer as claimed in claim 1, wherein the aforementioned thermosetting resin (A) further comprises phenolic resin (A3).

6. The resin composition for the insulating layer as claimed in claim 1, wherein the content of the inorganic filler (C) is 50 parts by mass or more and 300 parts by mass or less relative to a total of 100 parts by mass of the aforementioned thermosetting resin (A) and the aforementioned coumarin compound (B).

7. The resin composition for the insulating layer of claim 1 further contains an amine compound (D) that does not have a coumarin skeleton.

8. The resin composition of the insulating layer as claimed in claim 1 further contains core and outer shell rubber (E).

9. The resin composition for the insulating layer as claimed in claim 1, wherein the aforementioned inorganic filler (C) comprises at least one filler selected from the group consisting of silicon dioxide, talc, boehmite, magnesium hydroxide and aluminum hydroxide.

10. A prepreg comprising: at least one of an insulating resin composition as described in any one of claims 1 to 9 and a semi-cured form of the aforementioned insulating resin composition; and a fibrous substrate.

11. A resin-coated film comprising: a resin layer including at least one of an insulating resin composition as described in any one of claims 1 to 9 and a semi-cured form of the aforementioned insulating resin composition; and a support film.

12. A resin-coated metal foil comprising: a resin layer comprising at least one of an insulating resin composition as described in any one of claims 1 to 9 and a semi-cured form of the aforementioned insulating resin composition; and a metal foil.

13. A metal-clad laminate comprising: an insulating layer comprising a hardened form of a resin composition for insulating layer as claimed in any one of claims 1 to 9; and a metal layer.

14. A metal-clad laminate comprising: an insulating layer comprising a hardened prepreg as claimed in claim 10; and a metal layer.

15. A printed wiring board comprising: an insulating layer comprising a hardened form of a resin composition for insulating layer as claimed in any one of claims 1 to 9; and conductor wiring.

16. A printed wiring board comprising: an insulating layer comprising a hardened prepreg as claimed in claim 10; and conductor wiring.

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