Resin composition, prepreg, resin-attached film, resin-attached metal foil, metal-clad laminate, and printed circuit board

Abstract

The resin composition contains an epoxy compound and a curing agent. The epoxy compound comprises a phosphorus-containing epoxy compound having a phosphorus atom in its molecule. The curing agent comprises a phosphorus-containing acid anhydride having a phosphorus atom and an acid anhydride group in its molecule.

Description

Technology Field

[0001] The present disclosure generally relates to resin compositions, prepregs, resin-attached films, resin-attached metal foils, metal-clad laminates, and printed circuit boards. More specifically, the present disclosure relates to resin compositions containing an epoxy compound and a curing agent, prepregs, resin-attached films, resin-attached metal foils, metal-clad laminates, and printed circuit boards. Background Technology

[0002] Patent Document 1 (Japanese Patent Publication No. 2001-283639) discloses an insulating resin composition for a build-up substrate. This insulating resin composition for a build-up substrate has components A and B as essential components. Component A is an epoxy oligomer having two or more epoxy groups. Component B is an epoxy curing agent composed of 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide or dihydro-3-((6-oxide-6H-dibenz(c,e)(1,2)oxaphosphorin-6-yl)methyl)-2,5-furandion.

[0003] The insulating resin composition for a build-up substrate of Patent Document 1 is halogen-free, has excellent resistance to alkali, etc., and has excellent mechanical properties.

[0004] However, it is difficult to obtain good dielectric properties with the insulating resin composition for a build-up substrate of Patent Document 1. As communication technology is expected to continue advancing in the future, further improvement in dielectric properties and other properties is required for materials of printed circuit boards, which are responsible for one aspect of high-speed communication technology. Prior art literature

[0005] Japanese Patent Publication No. 2001-283639 The problem to be solved

[0006] The object of the present disclosure is to provide a resin composition, prepreg, resin-attached film, resin-attached metal foil, metal-clad laminate, and printed circuit board, which yield a cured product having a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance.

[0007] A resin composition according to one aspect of the present disclosure comprises an epoxy compound and a curing agent. The epoxy compound comprises a phosphorus-containing epoxy compound having a phosphorus atom in its molecule. The curing agent comprises a phosphorus-containing acid anhydride having a phosphorus atom and an acid anhydride group in its molecule.

[0008] A prepreg according to one aspect of the present disclosure comprises a substrate and a resin layer formed of a semi-finished product of the resin composition impregnated in the substrate.

[0009] A resin-attached film according to one aspect of the present disclosure comprises a resin layer formed from a semi-material of the resin composition and a support film that supports the resin layer.

[0010] A resin-attached metal foil according to one aspect of the present disclosure comprises a resin layer formed from a semi-material of the resin composition and a metal foil to which the resin layer is adhered.

[0011] A metal-clad laminate according to one aspect of the present disclosure comprises an insulating layer formed from a cured product of the resin composition or a cured product of the prepreg, and a metal layer formed on one or both sides of the insulating layer.

[0012] A printed circuit board according to one aspect of the present disclosure comprises an insulating layer formed from a cured product of the resin composition or a cured product of the prepreg, and conductive wiring formed on one or both sides of the insulating layer. Brief explanation of the drawing

[0013] FIG. 1 is a schematic cross-sectional view of a prepreg according to one embodiment of the present disclosure. FIG. 2A of FIG. 2 is a schematic cross-sectional view of a resin-attached film (without a protective film) according to one embodiment of the present disclosure. FIG. 2B is a schematic cross-sectional view of a resin-attached film (with a protective film) according to one embodiment of the present disclosure. FIG. 3 is a schematic cross-sectional view of a metal foil with resin attached according to one embodiment of the present disclosure. FIG. 4 is a schematic cross-sectional view of a metal-clad laminate according to one embodiment of the present disclosure. FIG. 5 is a schematic cross-sectional view of a printed circuit board according to one embodiment of the present disclosure. Specific details for implementing the invention

[0014] (1) Overview

[0015] In developing a resin composition that yields a cured product with excellent dielectric properties, the inventors noted that low dielectric constant resins have low flame resistance. If flame resistance is improved using conventional methods, there is a risk that the glass transition temperature (Tg) may decrease or adhesion properties may deteriorate. However, as a result of the aforementioned research, the inventors have developed the following resin composition.

[0016] The resin composition according to the present embodiment contains an epoxy compound and a curing agent. The epoxy compound includes a phosphorus-containing epoxy compound having a phosphorus atom in its molecule. The curing agent includes a phosphorus-containing acid anhydride having a phosphorus atom and an acid anhydride group in its molecule.

[0017] One of the features of the present embodiment is that the resin composition contains both a phosphorus-containing epoxy compound and a phosphorus-containing acid anhydride. When the phosphorus-containing epoxy compound and the phosphorus-containing acid anhydride are used together in this way, a cured product is obtained that has a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance. The cured product can form an insulating layer (50) of a printed circuit board (5) (see FIG. 5).

[0018] In addition, one of the features of the present embodiment is that the phosphorus-containing epoxy compound and the phosphorus-containing acid anhydride can react. When the phosphorus-containing epoxy compound and the phosphorus-containing acid anhydride are used together, if the cured product in which both are reacting (hereinafter referred to as the first cured product) and the cured product in which both are not reacting (hereinafter referred to as the second cured product) are compared, even if the phosphorus content of the first cured product and the second cured product is the same, the first cured product has superior flame resistance compared to the second cured product.

[0019] Here, one of the technical significances of increasing the glass transition temperature (Tg) is as follows. That is, if the glass transition temperature (Tg) is high, the solder heat resistance (reflow heat resistance) is improved. When solder heat resistance is improved, when soldering electronic components to a printed circuit board (5) using a reflow method, it is possible to suppress swelling of the insulating layer (50) or to suppress disconnection of the conductor wiring (51). In particular, good solder heat resistance is required for multilayer printed circuit boards having high-density wiring. If solder heat resistance is high, reliability of interlayer connection can be ensured even in a multilayer printed circuit board.

[0020] In addition, a hardened material with excellent dielectric properties is effective when the printed circuit board (5) is used for high-speed communication. Items required for the printed circuit board (5) for high-speed communication include, for example, (1) reducing the signal propagation delay, (2) reducing the dielectric loss of the signal, (3) controlling the characteristic impedance, (4) reducing crosstalk, etc.

[0021] In order to reduce the propagation delay of item (1), the conductor wiring (51) is shortened, that is, high-density wiring is performed, and the dielectric constant of the insulating layer (50) is lowered. The lower the dielectric constant, the faster the propagation speed.

[0022] Regarding item (2), as the frequency increases, it becomes important to lower the dielectric loss tangent along with the relative permittivity.

[0023] Regarding item (3), the dielectric constant of the insulating layer (50), the thickness of the insulating layer (50), the length of the conductor wiring (51), and the width of the conductor wiring (51) can be cited as factors for variation of the characteristic impedance. Here, when the characteristic impedance is kept constant, if the dielectric constant of the insulating layer (50) is low, the thickness of the insulating layer (50) can be reduced, and the conductor wiring (51) can be made shorter along with weight reduction. That is, it can contribute to item (1). In addition, if the dielectric constant of the insulating layer (50) is low, the width of the conductor wiring (51) can be increased when the interlayer thickness is kept constant, so the control of the characteristic impedance becomes easier, and it can also contribute to the reduction of crosstalk in item (4).

[0024] In addition, the cured material with excellent chemical resistance is resistant to alkaline aqueous solutions used for resist removal. Even if the formation and removal of the resist are performed repeatedly, the cured material remains resistant to alkaline aqueous solutions. Although alkaline aqueous solutions are not particularly limited, examples include sodium hydroxide aqueous solutions and potassium hydroxide aqueous solutions. On the other hand, the inner diameter of the hole is difficult to enlarge in the cured material with excellent chemical resistance even after desmere treatment.

[0025] (2) Details

[0026] (2.1) Resin composition

[0027] The resin composition according to the present embodiment has electrical insulating properties and can be used as a substrate material such as a printed circuit board. Specific examples of substrate materials include prepreg, resin-attached film, resin-attached metal foil, metal-clad laminate, and printed circuit board, but are not particularly limited to these.

[0028] The resin composition contains an epoxy compound and a curing agent. Preferably, the resin composition further contains an inorganic filler. The resin composition may further contain a curing accelerator.

[0029] The resin composition may additionally contain a flame retardant. In this case, the flame retardant is not a flame retardant in the broad sense, but a flame retardant in the narrow sense. That is, flame retardants in the broad sense include phosphorus-containing epoxy compounds and phosphorus-containing acid anhydrides, but flame retardants in the narrow sense do not include phosphorus-containing epoxy compounds and phosphorus-containing acid anhydrides. However, when comparing a cured product of a resin composition that does not contain a flame retardant (hereinafter referred to as the third cured product) with a cured product of a resin composition that additionally contains a flame retardant (hereinafter referred to as the fourth cured product), even if the phosphorus content of the third cured product and the fourth cured product is the same, the third cured product has superior flame resistance compared to the fourth cured product.

[0030] A resin composition is prepared, for example, as follows: that is, an epoxy compound and a curing agent are combined, and if necessary, an inorganic filler and a curing accelerator are combined, diluted with a suitable solvent, and then stirred and mixed to homogenize.

[0031] The resin composition is thermosetting. When heated, the resin composition becomes a semi-cured material, and when heated further, it becomes a cured material. The semi-cured material is a substance in a semi-cured state, and the cured material is a substance in a cured state (insoluble and infusible state). Here, the semi-cured state refers to the state of the intermediate stage (Stage B) of the curing reaction. The intermediate stage is the stage between the varnish state stage (Stage A) and the cured state stage (Stage C).

[0032] The components of the resin composition are described below.

[0033] (2.1.1) Epoxy compounds

[0034] An epoxy compound is a prepolymer and is a compound having at least two epoxy groups within its molecule. However, the term "resin" generally has two meanings: a resin as a material prior to a crosslinking reaction (e.g., an epoxy compound) and a resin as a product after a crosslinking reaction. In this specification, the term "resin" basically refers to the former.

[0035] In the present embodiment, the epoxy compound comprises a phosphorus-containing epoxy compound. The phosphorus-containing epoxy compound has a phosphorus atom in its molecule. The phosphorus-containing epoxy compound is reactive with respect to the phosphorus-containing acid anhydride described below.

[0036] Preferably, the phosphorus-containing epoxy compound has the structure of the following formula (1).

[0037]

[0038] If the phosphorus-containing epoxy compound has the structure of Formula (1) above, it is easy to obtain a cured product with a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance. The phosphorus-containing epoxy compound may have multiple structures of Formula (1) above within its molecules. Phosphorus-containing epoxy compounds are not particularly limited as long as they have phosphorus atoms in the molecule, but preferably, they contain one or more structures in the molecule derived from a substance selected from the group consisting of bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, phenyl type epoxy compounds, xylylene type epoxy compounds, aryl alkylene type epoxy compounds, triphenyl methane type epoxy compounds, anthracene type epoxy compounds, norbornene type epoxy compounds, fluorene type epoxy compounds, naphthalene type epoxy compounds, dicyclopentadiene type epoxy compounds, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-[2-(dihydroxynaphthyl)]-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0039] Preferably, the epoxy compound further comprises a polyfunctional epoxy compound. The polyfunctional epoxy compound does not contain phosphorus atoms in its molecule and also has at least two epoxy groups. If the epoxy compound further comprises a polyfunctional epoxy compound, properties characteristic of the polyfunctional epoxy compound can be imparted to the cured product.

[0040] As for multifunctional epoxy compounds, they are not particularly limited, but examples include bisphenol-type epoxy compounds, novolak-type epoxy compounds, biphenyl-type epoxy compounds, xylylene-type epoxy compounds, aryl-alkylene-type epoxy compounds, triphenyl-methane-type epoxy compounds, anthracene-type epoxy compounds, norbornene-type epoxy compounds, and fluorene-type epoxy compounds. The epoxy compounds contained in the resin composition may be one type or two or more types.

[0041] Specific examples of bisphenol-type epoxy compounds include bisphenol A-type epoxy compounds, bisphenol F-type epoxy compounds, and bisphenol S-type epoxy compounds, but are not specifically limited to these.

[0042] Specific examples of novolak-type epoxy compounds include phenol novolak-type epoxy compounds and cresol novolak-type epoxy compounds, but are not limited to these.

[0043] Specific examples of arylalkylene type epoxy compounds include phenol aralkyl type epoxy compounds, biphenyl aralkyl type epoxy compounds, biphenyl novolak type epoxy compounds, biphenyl dimethylene type epoxy compounds, trisphenol methane novolak type epoxy compounds, and tetramethyl biphenyl type epoxy compounds, but are not particularly limited to these.

[0044] Preferably, the polyfunctional epoxy compound comprises a polyfunctional epoxy compound having at least one of a naphthalene backbone and a dicyclopentadiene backbone in its molecule. In particular, the polyfunctional epoxy compound having a naphthalene backbone in its molecule may be referred to as a "naphthalene-type epoxy compound," and the polyfunctional epoxy compound having a dicyclopentadiene backbone in its molecule may be referred to as a "dicyclopentadiene-type epoxy compound."

[0045] The naphthalene backbone possesses rigidity and hydrophobicity. Therefore, if a multifunctional epoxy compound includes a naphthalene-type epoxy compound, it can impart heat resistance, low hygroscopicity, and a low linear expansion rate to the cured product.

[0046] Specific examples of naphthalene-type epoxy compounds include, but are not limited to, naphthalene backbone-modified cresol novolak-type epoxy compounds, naphthalene diol aralkyl-type epoxy compounds, naphthol aralkyl-type epoxy compounds, methoxynaphthalene-modified cresol novolak-type epoxy compounds, and methoxynaphthalene dimethylene-type epoxy compounds.

[0047] The dicyclopentadiene backbone is a bulky cyclic aliphatic hydrocarbon. Therefore, if a multifunctional epoxy compound includes a dicyclopentadiene-type epoxy compound, it can impart good dielectric properties, low hygroscopicity, and heat resistance to the cured product.

[0048] (2.1.2) Curing agent

[0049] The curing agent comprises a phosphorus-containing acid anhydride. The phosphorus-containing acid anhydride has a phosphorus atom and an acid anhydride group in its molecule. The phosphorus-containing acid anhydride is reactive with respect to the aforementioned phosphorus-containing epoxy compound.

[0050] The phosphorus-containing acid anhydride is not particularly limited, but, for example, preferably contains an acid anhydride group in the molecule with a structure represented by the following formula (A) and / or the following formula (B). The acid anhydride group preferably includes a cyclic acid anhydride group.

[0051]

[0052] In particular, it is preferable that the phosphorus-containing acid anhydride contains the above formula (A) in its molecule. As an example of a phosphorus-containing acid anhydride containing the above formula (A) in its molecule, dihydro-3-((6-oxide-6H-dibenz(c,e)(1,2)oxaphosphorin-6-yl)methyl)-2,5-furandion represented by the following formula (2) can be cited. If the phosphorus-containing acid anhydride is represented by the following formula (2), it is easy to obtain a cured product with a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance.

[0053]

[0054] Preferably, the curing agent further comprises a phosphorus-free curing agent. The phosphorus-free curing agent does not contain phosphorus atoms in its molecule. If the curing agent further comprises a phosphorus-free curing agent, properties characteristic of the phosphorus-free curing agent can be imparted to the cured product.

[0055] Preferably, the phosphorus-free curing agent comprises one or more compounds selected from the group consisting of polyfunctional acid anhydrides, alicyclic polyfunctional acid anhydrides, and styrene-maleic anhydride copolymers. By doing so, the cured product can be imparted with the characteristic properties of each of the polyfunctional acid anhydrides, alicyclic polyfunctional acid anhydrides, and styrene-maleic anhydride copolymers.

[0056] Polyfunctional acid anhydrides are compounds having at least two acid anhydride groups in their molecule. Polyfunctional acid anhydrides are not particularly limited, but examples include ethylene glycol bis-anhydro trimellitate (TMEG), pyromellitic anhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (BPDA), and 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propanoic acid dianhydride (BPADA). By using polyfunctional acid anhydrides rather than monofunctional acid anhydrides (compounds having one acid anhydride group in their molecule), the crosslinking density of the cured product is more likely to be increased. Therefore, polyfunctional acid anhydrides can improve the glass transition temperature (Tg) of the cured product.

[0057] A dicyclic polyfunctional acid anhydride is a polyfunctional acid anhydride and is a compound having at least one saturated or unsaturated carbon ring that is additionally non-aromatic. Examples of dicyclic polyfunctional acid anhydrides are not particularly limited, but include 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride (MCTC) and hydrogenated cyclohexane-1,2,4,5-tetracarboxylic acid dianhydride (H-PMDA). Dicyclic polyfunctional acid anhydrides can lower the dielectric constant of the cured product. Hydrogenated dicyclic polyfunctional acid anhydrides are particularly effective. Meanwhile, hydrogenation is synonymous with hydrogenation or hydrogenation reaction.

[0058] Styrene-maleic anhydride copolymer is a binary copolymer (copolymer) produced by copolymerizing styrene monomer and maleic anhydride, and is an acid anhydride having two or more acid anhydride groups. Styrene-maleic anhydride copolymer can improve the chemical resistance (especially alkali resistance) of the cured product.

[0059] Based on differences in the arrangement of styrene monomer and maleic anhydride, styrene-maleic anhydride copolymers are classified into alternating copolymers, random copolymers, block copolymers, and graft copolymers. Any of these copolymers may be used.

[0060] The acid value of the styrene-maleic anhydride copolymer is preferably in the range of 275 to 550. The acid value is indicated by the number of mg of potassium hydroxide required to neutralize free fatty acids present in 1 g of the styrene-maleic anhydride copolymer. If the acid value is 275 or higher, the adhesion of the cured product can be improved. Specifically, the peel strength of the metal-clad laminate (4) and the printed circuit board (5) can be improved.

[0061] In the styrene-maleic anhydride copolymer, the molar ratio of styrene monomer to maleic anhydride is not particularly limited. For example, the molar ratio is 1:1 to 3:1.

[0062] The weight-average molecular weight of the styrene-maleic anhydride copolymer is not particularly limited. For example, the weight-average molecular weight is within the range of 4,500 to 9,000.

[0063] Preferably, the phosphorus content relative to the total mass of the epoxy compound and the curing agent is within the range of 1.3 mass% or more and 3.7 mass% or less. By having a phosphorus content of 1.3 mass% or more, the flame resistance of the cured product can be improved. By having a phosphorus content of 3.7 mass% or less, the decrease in the chemical resistance (particularly alkali resistance) of the cured product can be suppressed. Meanwhile, if the resin composition additionally contains a flame retardant, the phosphorus content is based on the total mass of the epoxy compound, the curing agent, and the flame retardant.

[0064] The content of the phosphorus-containing acid anhydride is preferably within the range of 5 parts by mass or more and 70 parts by mass or less, more preferably within the range of 7 parts by mass or more and 66 parts by mass or less, with respect to 100 parts by mass of the total of the phosphorus-containing epoxy compound and the phosphorus-containing acid anhydride, and even more preferably within the range of 25 parts by mass or more and 55 parts by mass or less. By having a content of 5 parts by mass or more of the phosphorus-containing acid anhydride, the decrease in flame resistance and glass transition temperature (Tg) of the cured product can be suppressed. By having a content of 70 parts by mass or less of the phosphorus-containing acid anhydride, the decrease in flame resistance of the cured product can be suppressed.

[0065] Preferably, the equivalent ratio of the epoxy compound to the curing agent is within the range of 1:0.75 to 1:1.25. In other words, (equivalent of curing agent) / (equivalent of epoxy compound) is within the range of 0.75 or more and 1.25 or less. By keeping the equivalent ratio of the epoxy compound to the curing agent within the above range, the flame resistance of the cured product and the decrease in the glass transition temperature (Tg) can be suppressed.

[0066] Here, the equivalent weight (eq) of an epoxy compound is obtained by dividing the mass (g) of an epoxy compound contained in the resin composition by the epoxy equivalent weight (g / eq) of the epoxy compound. Meanwhile, the epoxy equivalent weight is the mass of an epoxy compound containing 1 equivalent of an epoxy group.

[0067] When a resin composition contains multiple epoxy compounds, the equivalent weight of the epoxy compounds in the resin composition is the sum of the equivalent weights of each epoxy compound.

[0068] The equivalent weight (eq) of a curing agent (acid anhydride) is obtained by dividing the mass (g) of the curing agent contained in the resin composition by the equivalent weight (g / eq) of the acid anhydride of the curing agent. Meanwhile, the equivalent weight of the acid anhydride is the mass of a curing agent containing 1 equivalent of an acid anhydride group.

[0069] In the case where the resin composition contains multiple curing agents, the equivalent weight of the curing agents in the resin composition is the sum of the equivalent weights of each curing agent.

[0070] (2.1.3) Weapon Filler

[0071] Inorganic fillers are not particularly limited, but examples include silica, calcium carbonate, titanium oxide, kaolin, clay, barium sulfate, zinc oxide, aluminum hydroxide, magnesium hydroxide, talc, mica, wollastonite, potassium titanate, aluminum boron, sepiolite, boron nitride, and silicon nitride. The shape of the inorganic filler is preferably spherical.

[0072] When the resin composition additionally contains an inorganic filler, the content of the inorganic filler is preferably within the range of 20 parts by mass or more and 150 parts by mass or less, with respect to 100 parts by mass of the total of the epoxy compound and the curing agent. By having an inorganic filler content of 20 parts by mass or more, the flame resistance of the cured product can be improved. In addition, the linear expansion coefficient of the cured product can be reduced, curing shrinkage can be suppressed, or thermal conductivity can be improved. By doing so, heat resistance to reflow can also be improved. Furthermore, in a printed circuit board (5) having two or more layers of conductor wiring (51), the reliability of interlayer connection can also be ensured. By having an inorganic filler content of 150 parts by mass or less, the cured product can have a low dielectric constant. In addition, the peel strength of the metal-clad laminate (4) and the printed circuit board (5) can be improved. Furthermore, it is possible to maintain fluidity suitable for molding while suppressing the decrease in fluidity during the melting of the resin composition.

[0073] (2.1.4) Curing accelerator

[0074] As a curing accelerator, examples include imidazole compounds and dicyandiamides, although they are not particularly limited. As for imidazole compounds, examples include 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, and 2-phenyl-4-methylimidazole.

[0075] (2.2) Prepreg

[0076] FIG. 1 shows a prepreg (1) according to the present embodiment. The prepreg (1) is in the form of a sheet or a film as a whole. The prepreg (1) is used as a material for a metal-clad laminate (4), a material for a printed circuit board (5), and for multilayering (build-up method) of a printed circuit board (5).

[0077] The prepreg (1) comprises a substrate (11) and a resin layer (10). The resin layer (10) is formed from a semi-material of a resin composition impregnated in the substrate (11).

[0078] One prepreg (1) comprises at least one substrate (11). The thickness of the substrate (11) is not particularly limited, but is, for example, within a range of 8 μm or more and 100 μm or less. Specific examples of the substrate (11) include woven fabric and non-woven fabric. Specific examples of the woven fabric include glass cloth, but are not particularly limited thereto. Specific examples of the non-woven fabric include glass non-woven fabric, but are not particularly limited thereto. Glass cloth and glass non-woven fabric are formed from glass fibers, but may also be formed from reinforcing fibers other than glass fibers. The type of glass constituting the glass fiber is not particularly limited, but examples include E glass, T glass, S glass, Q glass, UT glass, NE glass, and L glass. Specific examples of reinforcing fibers include aromatic polyamide fibers, liquid crystal polyester fibers, poly(paraphenylene benzobisoxazole) (PBO) fibers, and polyphenylene sulfide (PPS) resin fibers, but are not particularly limited to these.

[0079] When the prepreg (1) is heated, it melts once and then completely hardens to become a hardened state. The hardened prepreg (1) can form an insulating layer on the substrate.

[0080] The thickness of the prepreg (1) 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. By doing so, the thickness of the insulating layer can be reduced, thereby enabling the thinning of the substrate. The thickness of the prepreg (1) is preferably 10 μm or more.

[0081] Since the resin layer (10) of the prepreg (1) is formed from a resin composition according to the present embodiment, a cured product is obtained that has a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance.

[0082] (2.3) Resin-attached film

[0083] FIG. 2A shows a resin-attached film (2) according to the present embodiment. The resin-attached film (2) is in the form of a film or a sheet as a whole. The resin-attached film (2) comprises a resin layer (20) and a support film (21). The resin-attached film (2) is used for multilayering (build-up method) of a printed circuit board (5), etc.

[0084] The resin layer (20) is formed from a semi-material of the resin composition. The semi-material can become a hardened material by heating. In this way, the resin layer (20) can form an insulating layer.

[0085] 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. By doing so, the thickness of the insulating layer can be reduced, thereby enabling the thinning of the substrate. The thickness of the resin layer (20) is preferably 10 μm or more.

[0086] The support film (21) supports the resin layer (20). By supporting it in this way, the resin layer (20) becomes easier to handle.

[0087] The support film (21) is, for example, an electrical insulating film, but is not particularly limited thereto. Specific examples of the support film (21) include polyethylene terephthalate (PET) film, polyimide film, polyester film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, aramid film, polycarbonate film, and polyarylate film. The support film (21) is not limited to these films.

[0088] A release agent layer (not shown) may be provided on the surface of the support film (21) that supports the resin layer (20). By the release agent layer, the support film (21) can be peeled off from the resin layer (20) as needed. Preferably, after curing the resin layer (20) to form an insulating layer, the support film (21) is peeled off from the insulating layer.

[0089] In FIG. 2A, one side of the resin layer (20) is covered by a support film (21), but as shown in FIG. 2B, the other side of the resin layer (20) may be covered by a protective film (22). By covering both sides of the resin layer (20) in this way, the resin layer (20) becomes easier to handle. In addition, foreign matter can be prevented from adhering to the resin layer (20).

[0090] The protective film (22) is, for example, an electrical insulating film, but is not particularly limited thereto. Specific examples of the protective film (22) include polyethylene terephthalate (PET) film, polyolefin film, polyester film, and polymethylpentene film. The protective film (22) is not limited to these films.

[0091] A release agent layer (not shown) may be provided on the surface of the protective film (22) that overlaps the resin layer (20). By means of the release agent layer, the protective film (22) can be peeled off from the resin layer (20) as needed.

[0092] Since the resin layer (20) of the resin-attached film (2) is formed from a resin composition according to the present embodiment, a cured product is obtained that has a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance.

[0093] (2.4) Resin-attached metal foil

[0094] FIG. 3 shows a resin-attached metal foil (3) according to the present embodiment. The resin-attached metal foil (3) is in the form of a film or a sheet as a whole. The resin-attached metal foil (3) comprises a resin layer (30) and a metal foil (31). The resin-attached metal foil (3) is used for multilayering (build-up method) of a printed circuit board (5).

[0095] The resin layer (30) is formed from a semi-material of the resin composition. The semi-material can become a hardened material by heating. In this way, the resin layer (30) can form an insulating layer.

[0096] The thickness of the resin layer (30) 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. By doing so, the thickness of the insulating layer formed by curing the resin layer (30) can be reduced, thereby enabling the thinning of the substrate. The thickness of the resin layer (30) is preferably 10 μm or more.

[0097] A metal foil (31) has a resin layer (30) bonded to it. As a specific example of the metal foil (31), copper foil may be used, but it is not specifically limited thereto. The metal foil (31) can form a conductor wiring by removing unnecessary parts by etching in the subtractive method, etc.

[0098] The thickness of the metal foil (31) is not particularly limited, but is preferably 35 μm or less, more preferably 18 μm or less. It is preferable that the thickness of the metal foil (31) be 5 μm or more.

[0099] However, the metal foil (31) may be composed of a so-called carrier-attached ultra-thin metal foil (not shown) (e.g., ultra-thin copper foil). The carrier-attached ultra-thin metal foil has a three-layer structure. That is, the carrier-attached ultra-thin metal foil comprises a carrier, a release layer provided on the surface of the carrier, and an ultra-thin metal foil provided on the surface of the release layer. The ultra-thin metal foil is so thin that it is difficult to handle alone, and of course, it is thinner than the carrier. The carrier is a metal foil (e.g., copper foil) that serves to protect and support the ultra-thin metal foil. The carrier-attached ultra-thin metal foil has a certain thickness, making it easy to handle. The thicknesses of the ultra-thin metal foil and the carrier are not particularly limited, but for example, the thickness of the ultra-thin metal foil is within the range of 1 μm or more and 10 μm or less, and the thickness of the carrier is within the range of 18 μm or more and 35 μm or less. The ultra-thin metal foil can be peeled off from the release layer as needed.

[0100] When using a carrier-attached ultra-thin metal foil, a resin-attached metal foil (3) can be manufactured as follows. That is, a resin composition is applied to the surface of the carrier-attached ultra-thin metal foil and heated to form a resin layer (30). After that, the carrier is peeled off from the ultra-thin metal foil. The ultra-thin metal foil is adhered to the surface of the resin layer (30) as a metal foil (31). It is preferable that the peeling layer is peeled off together with the carrier and not remain on the surface of the ultra-thin metal foil, but even if it remains, it can be easily removed. The ultra-thin metal foil adhered to the surface of the resin layer (30) can be used as a seed layer in the Modified Semi-Additive Process (MSAP), and an electroplating treatment can be performed on this seed layer to form a conductor wiring.

[0101] Since the resin layer (30) of the resin-attached metal foil (3) is formed from a resin composition according to the present embodiment, a cured product is obtained that has a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance.

[0102] (2.5) Metal clad laminate

[0103] FIG. 4 shows a metal-clad laminate (4) according to the present embodiment. The metal-clad laminate (4) has an insulating layer (40) and a metal layer (41). The metal-clad laminate (4) is used as a material for a printed circuit board (5), etc.

[0104] The insulating layer (40) is formed from a cured resin composition or a cured prepreg (1). In FIG. 4, the insulating layer (40) has one substrate (42), but may have two or more substrates (42).

[0105] The thickness of the insulating layer (40) is not particularly limited. A thin thickness of the insulating layer (40) is effective for thinning the substrate. The thickness of the insulating layer (40) 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. The thickness of the insulating layer (40) is preferably 10 μm or more, and more preferably 15 μm or more.

[0106] The metal layer (41) is formed on one side or both sides of the insulating layer (40). The metal layer (41) is not particularly limited, but for example, a metal foil can be used. The metal foil is not particularly limited, but for example, a copper foil can be used. In FIG. 4, the metal layer (41) is formed on both sides of the insulating layer (40), but the metal layer (41) may be formed only on one side of the insulating layer (40). A metal-clad laminate (4) in which the metal layer (41) is formed on both sides of the insulating layer (40) is a double-sided metal-clad laminate. A metal-clad laminate (4) in which the metal layer (41) is formed only on one side of the insulating layer (40) is a single-sided metal-clad laminate.

[0107] The thickness of the metal layer (41) is not particularly limited, but is preferably 35 μm or less, more preferably 18 μm or less. It is preferable that the thickness of the metal layer (41) be 5 μm or more.

[0108] However, the metal layer (41) may be composed of the aforementioned carrier-attached ultra-thin metal foil. When using carrier-attached ultra-thin metal foil, a metal-clad laminate (4) can be manufactured as follows. That is, carrier-attached ultra-thin metal foil may be laminated and formed on one or both sides of a single prepreg (1), or multiple prepregs (1) may be stacked and carrier-attached ultra-thin metal foil laminated on one or both sides thereof. In this case, carrier-attached ultra-thin metal foil is stacked on the surface of the prepreg (1). After lamination, the carrier is peeled off from the ultra-thin metal foil. The ultra-thin metal foil is adhered as a metal layer (41) to the surface of the insulating layer (40), which is the cured product of the prepreg (1). It is preferable that the peeling layer be peeled off together with the carrier and not remain on the surface of the ultra-thin metal foil, but even if it remains, it can be easily removed. The ultra-thin metal foil adhered to the surface of the insulating layer (40) can be used as a seed layer in the Modified Semi-Additive Process (MSAP). A predetermined portion of the seed layer is covered with a plating resist, and electroplating is performed on the portion other than this. Afterward, the plating resist is peeled off, and the exposed seed layer is removed by etching or the like to form a conductor wiring.

[0109] The insulating layer (40) of the metal-clad laminate (4) is formed from a resin composition according to the present embodiment, so it has a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance. The glass transition temperature (Tg) is preferably 170°C or higher. The dielectric constant is preferably 3.60 or lower.

[0110] (2.6) Printed circuit board

[0111] FIG. 5 shows a printed circuit board (5) according to the present embodiment. The printed circuit board (5) has an insulating layer (50) and a conductor wiring (51). In this specification, "printed circuit board" means a state in which electronic components are not soldered and only wiring is present.

[0112] The insulating layer (50) is formed from a cured resin composition or a cured prepreg (1). The insulating layer (50) is similar to the insulating layer (40) of the metal-clad laminate (4) described above.

[0113] Conductive wiring (51) is formed on one side or both sides of the insulating layer (50). In FIG. 5, conductive wiring (51) is formed on both sides of the insulating layer (50), but conductive wiring (51) may be formed only on one side of the insulating layer (50). The method of forming the conductive wiring (51) is not particularly limited, but examples include the subtractive method, the semi-additive method (SAP), and the modified semi-additive method (MSAP). Since the adhesiveness of the insulating layer (50) is improved, even if the width of the conductive wiring (51) is thin, it is difficult for the conductive wiring (51) to peel off from the insulating layer (50). That is, with the printed circuit board (5) according to the present embodiment, high-density wiring can be realized.

[0114] Since the insulating layer (50) of the printed circuit board (5) is formed from a resin composition according to the present embodiment, it has a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance. Therefore, the printed circuit board (5) according to the present embodiment is considered to be particularly effective for high-speed communication.

[0115] (3) Summary

[0116] As is evident from the above embodiments, the present disclosure includes the following aspects. Hereinafter, symbols are enclosed in parentheses only to indicate the correspondence with the embodiments.

[0117] A resin composition according to the first aspect comprises an epoxy compound and a curing agent. The epoxy compound comprises a phosphorus-containing epoxy compound having a phosphorus atom in its molecule. The curing agent comprises a phosphorus-containing acid anhydride having a phosphorus atom and an acid anhydride group in its molecule.

[0118] According to this sun, a cured material is obtained that has a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance.

[0119] In the resin composition according to the second aspect, in the first aspect, the epoxy compound further comprises a multifunctional epoxy compound having at least two epoxy groups and not containing phosphorus atoms in the molecule.

[0120] According to this sun, properties characteristic of multi-functional epoxy compounds can be imparted to the cured material.

[0121] In the resin composition according to the third aspect, in the first or second aspect, the curing agent further comprises a phosphorus-free curing agent that does not contain phosphorus atoms in its molecule.

[0122] According to this sun, the cured material can be endowed with properties unique to phosphorus-free curing agents.

[0123] In the resin composition according to the fourth embodiment, in any one of the first to third embodiments, the phosphorus content relative to the total mass of the epoxy compound and the curing agent is within the range of 1.3 mass% or more and 3.7 mass% or less.

[0124] According to this sun, the flame resistance of the cured product can be improved by having a phosphorus content of 1.3 mass% or more. The decrease in the chemical resistance (especially alkali resistance) of the cured product can be suppressed by having a phosphorus content of 3.7 mass% or less.

[0125] In the resin composition according to the fifth embodiment, in any one of the first to fourth embodiments, the content of the phosphorus-containing acid anhydride is within the range of 5 parts by mass or more and 70 parts by mass or less with respect to 100 parts by mass of the total of the phosphorus-containing epoxy compound and the phosphorus-containing acid anhydride.

[0126] According to this sun, by having a content of phosphorus-containing acid anhydride of 5 parts by mass or more, the decrease in flame resistance and glass transition temperature (Tg) of the cured product can be suppressed. By having a content of phosphorus-containing acid anhydride of 70 parts by mass or less, the decrease in flame resistance of the cured product can be suppressed.

[0127] In the resin composition according to the 6th embodiment, in any one of the 2nd to 5th embodiments, the multifunctional epoxy compound comprises a multifunctional epoxy compound having at least one skeleton among a naphthalene skeleton and a dicyclopentadiene skeleton in the molecule.

[0128] According to this sun, if the multifunctional epoxy compound includes a naphthalene-type epoxy compound, the cured product can be imparted with heat resistance, low hygroscopicity, and a low linear expansion coefficient. If the multifunctional epoxy compound includes a dicyclopentadiene-type epoxy compound, the cured product can be imparted with good dielectric properties, low hygroscopicity, and heat resistance.

[0129] In the resin composition according to the 7th embodiment, in any one of the 3rd to 6th embodiments, the phosphorus-free curing agent comprises one or more compounds selected from the group consisting of polyfunctional acid anhydrides, alicyclic polyfunctional acid anhydrides, and styrene-maleic anhydride copolymers.

[0130] According to this sun, the characteristic properties of polyfunctional acid anhydrides, alicyclic polyfunctional acid anhydrides, and styrene-maleic anhydride copolymers, respectively, can be imparted to the cured product.

[0131] In the resin composition according to the 8th sun, in any one of the 1st to 7th suns, the phosphorus-containing epoxy compound has the structure of the following formula (1).

[0132]

[0133] According to this sun, it is easy to obtain a cured product with a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance.

[0134] In the resin composition according to the ninth embodiment, in any one of the first to eighth embodiments, the equivalent ratio of the epoxy compound to the curing agent is within the range of 1:0.75 to 1:1.25.

[0135] According to this sun, by keeping the equivalent ratio of the epoxy compound to the curing agent within the above range, the flame resistance and glass transition temperature (Tg) of the cured product can be suppressed.

[0136] The resin composition according to the 10th embodiment further contains an inorganic filler in any one of the 1st to 9th embodiments. The content of the inorganic filler is within the range of 20 parts by mass or more and 150 parts by mass or less, with respect to 100 parts by mass of the total of the epoxy compound and the curing agent.

[0137] According to this sun, by having an inorganic filler content of 20 parts by mass or more, the linear expansion rate of the cured product can be reduced, curing shrinkage can be suppressed, or thermal conductivity can be improved. By having an inorganic filler content of 150 parts by mass or less, the decrease in fluidity during melting of the resin composition can be suppressed.

[0138] The prepreg (1) according to the 11th sun comprises a substrate (11) and a resin layer (10) formed from a semi-material of a resin composition according to any one of the 1st to 10th suns that is impregnated into the substrate (11).

[0139] According to this sun, a cured material is obtained that has a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance.

[0140] A resin-attached film (2) according to the 12th sun comprises a resin layer (20) formed from a semi-material of a resin composition according to any one of the 1st to 10th suns, and a support film (21) that supports the resin layer (20).

[0141] According to this sun, a cured material is obtained that has a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance.

[0142] A resin-attached metal foil (3) according to the 13th sun comprises a resin layer (30) formed from a semi-material of a resin composition according to any one of the 1st to 10th suns, and a metal foil (31) to which the resin layer (30) is adhered.

[0143] According to this sun, a cured material is obtained that has a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance.

[0144] A metal-clad laminate (4) according to the 14th sun has an insulating layer (40) formed from a cured resin composition according to any one of the 1st to 10th suns or a cured prepreg (1) according to the 11th sun, and a metal layer (41) formed on one side or both sides of the insulating layer (40).

[0145] According to this sun, the insulating layer (40) has a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance.

[0146] A printed circuit board (5) according to the 15th sun has an insulating layer (50) formed from a cured resin composition according to any one of the 1st to 10th suns or a cured prepreg (1) according to the 11th sun, and a conductive wiring (51) formed on one side or both sides of the insulating layer (50).

[0147] According to this sun, the insulating layer (50) has a high glass transition temperature (Tg) and excellent dielectric properties, adhesion, chemical resistance, and flame resistance.

[0148] Examples

[0149] The present disclosure will be explained in detail below by way of examples. However, the present disclosure is not limited to examples.

[0150] (1) Resin composition

[0151] As a raw material for the resin composition, the following were prepared.

[0152] (1.1) Epoxy compounds

[0153] · Phosphorus-containing epoxy compound (manufactured by Shin-Nippon Tetsuya Sumikin Chemical Co., Ltd., trade name "FX-289-P", epoxy equivalent: 390 g / eq, phosphorus content: 3.5 mass%)

[0154] · Dicyclopentadiene type epoxy compound (manufactured by DIC Corporation, trade name "HP-7200HHH", epoxy equivalent: 280–290 g / eq, softening point: 100–105℃)

[0155] · Naphthalene-type epoxy compound (manufactured by DIC Corporation, trade name "HP-9500", epoxy equivalent: 230 g / eq)

[0156] (1.2) Curing agent

[0157] · Phosphorus-containing acid anhydride (dihydro-3-((6-oxide-6H-dibenz(c,e)(1,2)oxaphosphorin-6-yl)methyl)-2,5-furandion, acid anhydride equivalent: 332 g / eq, see Formula (2))

[0158] · Polyfunctional acid anhydride (manufactured by Shin-Nihon Rica Co., Ltd., trade name "Ricacid TMEG-S", ethylene glycol bis-anhydro trimellitate, acid anhydride equivalent: 204 g / eq, softening point: 64–76°C)

[0159] · Cyclic polyactive acid anhydride (manufactured by DIC Corporation, trade name "B-4500", 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride (MCTC), powdered acid anhydride, acid anhydride equivalent: 132 g / eq)

[0160] · Styrene-maleic anhydride copolymer (Manufactured by CRAY VALLEY, trade name "SMA EF30", styrene:maleic anhydride (molar ratio) = 3:1, acid value: 275–285 KOH mg / g, acid anhydride equivalent: 280 g / eq, weight average molecular weight: 9500)

[0161] (1.3) Weapon Filler

[0162] · Silica (Made by Zhejiang Huafei Electronic Materials Co., Ltd., Product Name "VF-40-YE3", Spherical, Particle Size: 1.51μm (D50) / Top Cut 10μm)

[0163] (1.4) Curing accelerator

[0164] · Imidazole compound (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name "2E4MZ", 2-ethyl-4-methylimidazole)

[0165] (1.5) Flame retardant

[0166] · Dispersible flame retardant (Manufactured by Clariant Japan Co., Ltd., Product name "OP-935", Aluminum phosphinate, Phosphorus content: 23 mass%)

[0167] · Reactive flame retardant (Manufactured by Chemutura Japan Co., Ltd., Product name "Emerald 2000", Phosphorus content: 9.8 mass%)

[0168] The raw materials of the resin composition above are summarized in Table 1.

[0169]

[0170] Then, an epoxy compound, a curing agent, an inorganic filler, a curing accelerator, and a flame retardant were mixed in the amounts shown in Table 2, diluted with a solvent (methyl ethyl ketone), and homogenized by stirring and mixing to prepare a resin composition in the form of a varnish.

[0171]

[0172] Table 3 shows the equivalents of the epoxy compound and the curing agent, the ratio of the equivalents of both, and the phosphorus content of the epoxy compound, curing agent, flame retardant, and resin composition.

[0173]

[0174] (2) Prepreg

[0175] The prepreg was manufactured by impregnating the above resin composition into a glass cloth (manufactured by Nitto Boseki Co., Ltd., product name "7628 Type Cloth"), heating and drying it at 110 to 140°C using a non-contact type heating unit to remove the solvent in the resin composition and semi-curing the resin composition. The resin content (content of the resin composition) of the prepreg was within the range of 65 mass% or more and 75 mass% or less with respect to the total mass of the prepreg.

[0176] (3) Metal clad laminate

[0177] The metal-clad laminate was manufactured as a copper-clad laminate by overlapping eight sheets of prepreg (340 mm × 510 mm), overlapping copper foil (manufactured by Mitsui Mining & Co., Ltd., thickness 18 μm, ST foil) on both sides with the roughened surface facing inward, and then laminating and molding the mixture by heating and pressurizing. The heating and pressurizing conditions were 180°C, 2.94 MPa, and 60 minutes.

[0178] (4) Test

[0179] (4.1) Glass transition temperature (Tg)

[0180] The glass transition temperature of the prepreg was measured using a viscoelastic spectrometer "DMS6100" manufactured by Seiko Instruments Co., Ltd. Specifically, the measurement was performed with a bending modulus frequency of 10 Hz, and the temperature at which tanα showed a maximum when heated from room temperature to 280°C under the condition of a heating rate of 5°C / min was defined as the glass transition temperature.

[0181] (4.2) Relative permittivity (Dk)

[0182] Using the Hewlett-Packard "Impedance / Material Analyzer 4291A", the relative permittivity of a copper-clad laminate at 1 GHz was measured in accordance with IPC-TM-650 2.5.5.9.

[0183] (4.3) Peel strength

[0184] The peel strength of the copper foil (thickness 18 μm) on the surface of the copper-clad laminate was measured in accordance with JIS C 6481. Specifically, the copper foil was peeled at a speed of about 50 mm per minute, and the peel strength (kN / m) at that time was measured as the peel strength.

[0185] (4.4) Alkali resistance

[0186] A copper-clad laminate with a plate thickness of 0.8 mm was manufactured in the same manner as above. After removing the copper foil on the surface of the copper-clad laminate by etching, it was immersed in an aqueous sodium hydroxide solution (10 mass%) at 70°C for 30 minutes. Then, the mass loss rate was calculated from the mass before and after immersion. The results are divided as follows and are shown in Table 4.

[0187] "A": Mass reduction rate is 0 mass% or more and less than 0.2 mass%

[0188] "B": Mass reduction rate is 0.2 mass% or more and less than 0.3 mass%

[0189] "C": Mass reduction rate of 0.3 mass% or more

[0190] (4.5) Flame resistance

[0191] Copper-clad laminates with plate thicknesses of 0.8 mm, 1.2 mm, and 1.6 mm were manufactured in the same manner as above by adjusting the number of prepregs. After removing the copper foil from the surface of each copper-clad laminate by etching, a flammability test was performed in accordance with Underwriters Laboratories' "Test for Flammability of Plastic Materials-UL94" to evaluate flammability. Satisfying V-0 is "OK," and not satisfying it is "NG." Table 4 shows the plate thickness and whether V-0 is satisfied at that plate thickness.

[0192] "1.6mm OK": 1.6mm, 1.2mm, and 0.8mm are all OK

[0193] "1.2mm OK": 1.6mm is NG, 1.2mm and 0.8mm are OK

[0194] "0.8mm NG": 1.6mm, 1.2mm, and 0.8mm are all NG

[0195] Explanation of the symbols

[0196] 1 prepreg 10 resin layers 11 entries 2 Resin adhesive film 20 resin layer 21 Support Film 22 protective film 3. Metal foil attached to resin 30 resin layers 31 Metal foil 4 metal-clad laminates 40 insulation layers 41 metal layer 5 printed circuit boards 50 insulation layers 51 Conductor Wiring

Claims

Claim 1 A resin composition for printed circuit boards comprising an epoxy compound and a curing agent, wherein the epoxy compound comprises a phosphorus-containing epoxy compound having a phosphorus atom in its molecule, the curing agent comprises a phosphorus-containing acid anhydride having a phosphorus atom and an acid anhydride group in its molecule, and a phosphorus-free curing agent not containing a phosphorus atom in its molecule, and the phosphorus-free curing agent comprises a dicyclic polyfunctional acid anhydride. Claim 2 A resin composition for a printed circuit board according to claim 1, wherein the epoxy compound further comprises a multifunctional epoxy compound having at least two epoxy groups and not containing phosphorus atoms in the molecule. Claim 3 A resin composition for a printed circuit board according to claim 1, wherein the phosphorus content relative to the total mass of the epoxy compound and the curing agent is within the range of 1.3 mass% or more and 3.7 mass% or less. Claim 4 A resin composition for a printed circuit board according to claim 1, wherein the content of the phosphorus-containing acid anhydride is within the range of 5 parts by mass or more and 70 parts by mass or less, based on 100 parts by mass of the total of the phosphorus-containing epoxy compound and the phosphorus-containing acid anhydride. Claim 5 A resin composition for a printed circuit board according to claim 2, wherein the multifunctional epoxy compound comprises a multifunctional epoxy compound having at least one skeleton among a naphthalene backbone and a dicyclopentadiene backbone in the molecule. Claim 6 In claim 1, the phosphorus-containing epoxy compound has the structure of the following formula (1), Resin composition for printed circuit boards. Claim 7 A resin composition for a printed circuit board according to claim 1, wherein the equivalent ratio of the epoxy compound to the curing agent is within the range of 1:0.75 to 1:1.

25. Claim 8 A resin composition for a printed circuit board according to claim 1, further containing an inorganic filler, wherein the content of the inorganic filler is within the range of 20 parts by mass or more and 150 parts by mass or less, with respect to 100 parts by mass of the total of the epoxy compound and the curing agent. Claim 9 A prepreg having a substrate and a resin layer formed from a semi-finished product of the resin composition for a printed circuit board described in claim 1, which is impregnated into the substrate. Claim 10 A resin-attached film comprising a resin layer formed from a semi-material of the resin composition for a printed circuit board described in claim 1, and a support film supporting the resin layer. Claim 11 A resin-attached metal foil having a resin layer formed from a semi-material of the resin composition for a printed circuit board described in claim 1, and a metal foil to which the resin layer is adhered. Claim 12 A metal-clad laminate comprising an insulating layer formed from a cured resin composition for a printed circuit board described in claim 1 or a cured prepreg described in claim 9, and a metal layer formed on one or both sides of the insulating layer. Claim 13 A printed circuit board having an insulating layer formed from a cured product of a resin composition for a printed circuit board described in claim 1 or a cured product of a prepreg described in claim 9, and conductive wiring formed on one or both sides of the insulating layer. Claim 14 delete Claim 15 delete

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