Curable resin material, prepreg, resin film, metal-clad laminate, printed wiring board, and semiconductor package

Abstract

Provided is a curable resin material which contains: a resin (A) containing an indene ring, a vinylbenzyl group, and an arylalkyl group other than the vinylbenzyl group; and a phosphorus atom-containing compound (B).

Description

Curable resin materials, prepregs, resin films, metal-clad laminates, printed circuit boards, and semiconductor packages

[0001] This disclosure relates to curable resin materials, prepregs, resin films, metal-clad laminates, printed circuit boards, and semiconductor packages.

[0002] Metal-clad laminates, such as copper-clad laminates, prepregs that can be used for metal-clad laminates, and semiconductor packages using metal-clad laminates are used in a wide variety of electronic devices, including mobile communication devices such as smartphones, their base station equipment, network infrastructure equipment such as servers, routers, and large servers, large computers, personal computers, and industrial computers. They are also used in electronic devices installed in home appliances and automobiles. In particular, the demand for electronic communication equipment to process vast amounts of data at high speed is increasing due to the spread of 5G.

[0003] In electronic devices, when processing vast amounts of data at high speed, substrate materials with low transmission loss in the high-frequency range are required. Low dielectric constant and low dielectric loss tangent resins are used as substrate materials to provide substrates with low transmission loss, but with the recent advancements in communication technology, there is a need for the development of resins with even lower dielectric constant and low dielectric loss tangent.

[0004] Patent Document 1 discloses a curable vinylbenzyl compound having an indene ring structure into which vinylbenzyl groups are introduced, which can be used as a curable vinylbenzyl compound that has excellent low dielectric constant, low dielectric loss tangent, high heat resistance, and low water absorption.

[0005] Japanese Patent Publication No. 2003-277440

[0006] One of the objectives of this disclosure is to provide curable resin materials, prepregs, resin films, metal-clad laminates, printed circuit boards, and semiconductor packages that exhibit excellent flame retardancy in cured products.

[0007] This disclosure includes, but is not limited to, the following embodiments. One embodiment relates to a curable resin material comprising a resin (A) comprising an indene ring, a vinylbenzyl group, and an arylalkyl group other than a vinylbenzyl group, and a phosphorus atom-containing compound (B).

[0008] This disclosure makes it possible to provide curable resin materials, prepregs, resin films, metal-clad laminates, printed circuit boards, and semiconductor packages that exhibit excellent flame retardancy in cured products.

[0009] The embodiments of the present invention will be described in detail below. The present invention is not limited to the embodiments described below.

[0010] In this disclosure, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described stepwise in this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. Furthermore, the upper or lower limits of numerical ranges described in this disclosure may be replaced with the values ​​shown in the examples. In this disclosure, each component may contain one or more of the corresponding substances unless otherwise specified. In this disclosure, the content of each component in the curable resin material means the total amount of the multiple substances present in the curable resin material if there are multiple substances corresponding to each component in the curable resin material, unless otherwise specified.

[0011] In this disclosure, unless otherwise specified, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) are values ​​measured by the following procedure. The weight-average molecular weight and number-average molecular weight are converted from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The calibration curve is approximated by a cubic equation using standard polystyrene: TSK standard POLYSTYRENE (Type; A-2500, A-5000, F-20, F-80) (manufactured by Tosoh Corporation, trade name). The GPC conditions are shown below.

[0012] Instrument: High-speed GPC instrument "HLC-8320GPC" (Tosoh Corporation, product name) Detector: Ultraviolet absorption detector "UV-8320" (Tosoh Corporation, product name) Columns: Guard column; TSKgel guardcolumn Super(HZ)-M+, Column; TSKgel SuperMultipore HZ-M (2), Reference column; TSKgel SuperH-RC (2) (all Tosoh Corporation, product names) Column size: 4.6 × 20 mm (guard column), 4.6 × 150 mm (column), 6.0 × 150 mm (reference column) Eluent: Tetrahydrofuran Sample concentration: 10 mg / 1 mL Injection volume: 20 μL or 2 μL Flow rate: 0.35 mL / min Measurement temperature: 40°C

[0013] A curable resin material according to one embodiment of the present disclosure is a curable resin material comprising a resin (A) containing an indene ring, a vinylbenzyl group, and an arylalkyl group other than a vinylbenzyl group, and a phosphorus atom-containing compound (B).

[0014] Resin (A) can be any compound, as long as it contains an indene ring, a vinylbenzyl group, and an arylalkyl group other than a vinylbenzyl group in its molecular structure. There are no other restrictions on specific structure, molecular weight, etc., and a wide variety of compounds can be used. Resin (A) may be used alone or in combination of two or more types.

[0015] Regarding the vinylbenzyl groups contained in resin (A), the vinylbenzyl groups may be o-vinylbenzyl groups, m-vinylbenzyl groups, or p-vinylbenzyl groups. Among these, p-vinylbenzyl groups are preferred because they result in compounds with excellent dielectric properties in the cured product. The proportion of p-vinylbenzyl groups in the total vinylbenzyl groups contained in resin (A) may be 10 mol% or more, 20 mol% or more, or 30 mol% or more. It may also be 100 mol% or less, 80 mol% or less, or 70 mol% or less. The proportion of p-vinylbenzyl groups in the total vinylbenzyl groups contained in resin (A) may be in the range of 10 to 100 mol%. If the proportion of p-vinylbenzyl groups is less than 100 mol%, the remaining vinylbenzyl groups may be m-vinylbenzyl groups.

[0016] Regarding arylalkyl groups other than vinylbenzyl groups contained in resin (A) (hereinafter sometimes referred to as "arylalkyl groups"), the number of carbon atoms in the alkyl group within the arylalkyl group is not particularly limited, but may be in the range of 1 to 6, for example. Furthermore, the alkyl group may be linear or have a branched structure. Specific examples of alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, n-pentyl group, isopentyl group, neopentyl group, t-pentyl group, n-hexyl group, isohexyl group, etc. Among these, it is preferable that the alkyl group within the arylalkyl group has a relatively small number of carbon atoms, as this results in a resin with excellent dielectric properties. For example, the alkyl group within the arylalkyl group may be a methyl group or an ethyl group, or it may be a methyl group.

[0017] The aryl group in the arylalkyl group is not particularly limited as long as it is not a styryl group, and examples include a phenyl group, a naphthyl group, and structural parts having one or more substituents on their aromatic rings. Substituents on the aromatic ring include, for example, halogen atoms such as fluorine, chlorine, bromine, or iodine; alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t-pentyl, n-hexyl, and isohexyl groups; alkoxy groups represented as RO- where R is one of the aforementioned alkyl groups; polymerizable unsaturated bond-containing groups such as vinyl, vinyloxy, allyl, allyloxy, (meth)acryloyl, and (meth)acryloyloxy groups; aryl groups such as phenyl, tolyl, xylyl, mesityl, and naphthyl groups; and aryloxy groups such as phenyloxy, tolyloxy, xylyloxy, mesityloxy, and naphthyloxy groups.

[0018] The arylalkyl group may not have a polymerizable unsaturated bond. The aryl group in the arylalkyl group may be a phenyl group, a naphthyl group, or a group having 1 to 3 alkyl groups with 1 to 3 carbon atoms on these aromatic rings.

[0019] In the resin (A), the vinylbenzyl group and the arylalkyl group other than the vinylbenzyl group may be directly bonded to the indene ring. As an example of the resin (A), it contains two or more compounds having different structures among the compounds represented by the following general formula (1), and R present in the resin １ , R ２ and R ３ at least one of which is a vinylbenzyl group, and R present in the resin １ , R ２ and R ３ at least one of which is an arylalkyl group other than the vinylbenzyl group, there is provided a resin (A1).

[0020]

[0021] [In the general formula (1), R １ , R ２ and R ３ are each independently a hydrogen atom, a vinylbenzyl group, or an arylalkyl group other than the vinylbenzyl group. R ４ is a hydrogen atom, a halogen atom, or a monovalent organic group, and all of the four R ４ may be different from each other, and two or more of the four R ４ may be the same as each other. ]

[0022] In the general formula (1), R １ , R ２ and R ３ are each independently a hydrogen atom, a vinylbenzyl group, or an arylalkyl group other than the vinylbenzyl group. The details of the arylalkyl group are as described above.

[0023] In the general formula (1), R ４is a hydrogen atom, a halogen atom, or a monovalent organic group. Examples of halogen atoms include fluorine, chlorine, bromine, or iodine. Examples of monovalent organic groups include alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t-pentyl, n-hexyl, and isohexyl groups; alkoxy groups represented as RO-, where R is one of the aforementioned alkyl groups; polymerizable unsaturated bond-containing groups, such as vinyl, vinyloxy, allyl, allyloxy, (meth)acryloyl, and (meth)acryloyloxy groups; aryl groups, such as phenyl, tolyl, xylyl, mesityl, and naphthyl groups; and aryloxy groups, such as phenyloxy, tolyloxy, xylyloxy, mesityloxy, and naphthyloxy groups. R in general formula (1) ４ All of them may be hydrogen atoms.

[0024] In resin (A1), R present in the resin １ , R ２ and R ３ At least one of them is a vinylbenzyl group, and at least one is an arylalkyl group. The resin (A1) is R １ , R ２ and R ３ A compound in which one of the atoms is a vinylbenzyl group, one is an arylalkyl group, and one is a hydrogen atom, R １ , R ２ and R ３ A compound in which two of the groups are vinylbenzyl groups and one is an arylalkyl group, R １ , R ２ and R ３ A compound in which one of the groups is a vinylbenzyl group and the other two are arylalkyl groups, R １ , R ２ and R ３ A compound in which 1 to 3 of the groups are vinylbenzyl groups and the others are hydrogen atoms, R １ , R ２ and R ３ A compound in which one to three of the atoms are arylalkyl groups and the others are hydrogen atoms, R １ , R２ and R ３ The compound may contain at least one compound in which all atoms are hydrogen atoms. In a compound having multiple arylalkyl groups in one molecule, the arylalkyl groups may all be different, or some or all of them may be the same.

[0025] In resin (A1), the average of the total number of vinylbenzyl groups and arylalkyl groups in one molecule is preferably 1.5 or higher, more preferably 1.8 or higher, and particularly preferably 2.0 or higher, as this results in excellent curability. It may also be 3.0 or lower, 2.8 or lower, or 2.5 or lower. The average of the total number of vinylbenzyl groups and arylalkyl groups in one molecule may be in the range of 1.5 to 3.0.

[0026] Furthermore, the ratio of vinylbenzyl groups to the total number of vinylbenzyl groups and arylalkyl groups present in the resin (A1) may be 30 mol% or more, 60 mol% or more, or 85 mol% or more. It may also be 99 mol% or less, 95 mol% or less, or 80 mol% or less. The ratio of vinylbenzyl groups to the total number of vinylbenzyl groups and arylalkyl groups may be in the range of 30 to 99 mol%.

[0027] Resin (A1) is a compound identified by its molecular structure, and its manufacturing method is not particularly limited. One example of a method for producing resin (A1) is to react indene, styrene having a methyl halide group, and an aromatic compound having an alkyl halide corresponding to an arylalkyl group in the presence of a basic compound.

[0028] Examples of styrenes having a methyl halide group include o-chloromethylstyrene, m-chloromethylstyrene, and p-chloromethylstyrene. These may be used individually or in combination of two or more. Examples of aromatic compounds having an alkyl halide include α-chlorotoluene, α-chloroxylene, and 1-(chloromethyl)naphthalene. These may be used individually or in combination of two or more.

[0029] The ratio of styrene having a methyl halide group to the total number of moles of styrene having a methyl halide group and aromatic compounds having an alkyl halide group may be 30 mol% or more, 60 mol% or more, or 85 mol% or more. It may also be 99 mol% or less, 95 mol% or less, or 80 mol% or less. The ratio of styrene having a methyl halide group to the total number of moles of styrene having a methyl halide group and aromatic compounds having an alkyl halide group may be in the range of 30 to 99 mol%.

[0030] The total number of moles of styrene having a methyl halide group and an aromatic compound having an alkyl halide per mole of indene may be 1.5 moles or more, 1.8 moles or more, or 2.0 moles or more. It may also be 3.0 moles or less, 2.8 moles or less, or 2.5 moles or less. The total number of moles of styrene having a methyl halide group and an aromatic compound having an alkyl halide per mole of indene may be in the range of 1.5 to 3.0 moles.

[0031] Examples of basic compounds include alkali metal hydroxides and alkali metal alkoxides. These may be used individually or in combination of two or more.

[0032] A phase-transfer catalyst may be used in the above reaction. Examples of phase transfer catalysts include quaternary ammonium salts such as tetra-n-butylammonium chloride, tetra-n-butylammonium bromide (tetra-n-butylammonium bromide), tetraethylammonium chloride, tetraethylammonium bromide, tetrapropylammonium chloride, tetrapropylammonium bromide, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, benzyltributylammonium chloride, benzyltributylammonium bromide, benzyldimethyltetradecylammonium chloride, tricaprylmethylammonium chloride, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, trioctylmethylammonium chloride, and tetra-n-butylammonium bisulfate; and quaternary phosphonium salts such as tetra-n-butylphosphonium chloride, tetra-n-butylphosphonium bromide, tetraphenylphosphonium chloride, tetraphenylphosphonium bromide, benzyltriphenylphosphonium chloride, and benzyltriphenylphosphonium bromide. These may be used individually or in combination of two or more types.

[0033] The above reaction may be carried out, for example, under heating and stirring conditions. The heating temperature may be around 50 to 100°C. The above reaction can also be carried out by solution polymerization. The solvent used is not particularly limited as long as it can dissolve the reaction raw materials and has a boiling point above the reaction temperature, but examples include aromatic hydrocarbon solvents such as toluene, xylene, and mesitylene. These may be used individually or in combination of two or more.

[0034] Polymerization inhibitors may be used in the reaction system as needed. Examples of polymerization inhibitors include hydroquinone, methylhydroquinone, t-butylhydroquinone, 2,6-di-t-butylhydroquinone, 2,5-di-t-butylhydroquinone, hydroquinone monomethyl ether, 1,4-benzoquinone, 2-t-butyl-1,4-benzoquinone, 2-t-butylphenol, 2,4-di-t-butylphenol, 2,6-di-t-butylphenol, cresol, catechol, 4-t-butylcatechol, pyrogallol, and 4 Examples include methoxyphenol, thiodiphenylamine, phenothiazine, 3,7-dioctylphenothiazine, 3,7-dicumylphenothiazine, 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl, and bis(2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl) sebacate. These may be used individually or in combination of two or more.

[0035] The product obtained from the above reaction may be purified by known methods such as concentration, reprecipitation, and washing, if necessary.

[0036] Another example of resin (A) is a prepolymer (A2) obtained by polymerizing some of the vinyl groups in resin (A1). In this disclosure, a prepolymer is a polymer in which some of the polymerizable groups in the raw material remain without undergoing a polymerization reaction, and which has curability due to the remaining polymerizable groups.

[0037] The prepolymer (A2) may be prepared by combining resin (A1) with other reaction materials other than resin (A1). The proportion of resin (A1) in the total monomer of the prepolymer (A2) may be 50 mol% or more, 80 mol% or more, or 100 mol%.

[0038] The method for producing the prepolymer (A2) is not particularly limited and can be produced by polymerizing a monomer containing resin (A1) using a general method. One example of such a method is radical polymerization.

[0039] Polymerization initiators used in radical polymerization are not particularly limited, and examples include azo polymerization initiators and organic peroxide polymerization initiators. Examples of azo polymerization initiators include 2,2'-azobis(2,4,4-trimethylpentane), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 1,1'-azobis(cyclohexane-1-carbonitride), and dimethyl-1 Examples include 1'-azobis(1-cyclohexanecarboxylate), 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylpropanenitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 4,4'-azobis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl4-cyanopentanoate), etc. Examples of organic peroxide polymerization initiators include dicumyl peroxide, dibenzoyl peroxide, 2-butanone peroxide, t-butyl perbenzoate, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, bis(t-butylperoxyisopropyl)benzene, and t-butyl hydroperoxide. These may be used individually or in combination of two or more.

[0040] Polymerization reactions may be carried out in a solvent. Examples of solvents that can be used include toluene and xylene. These may be used individually or in combination of two or more.

[0041] The weight-average molecular weight (Mw) of the prepolymer (A2) is not particularly limited, but for example, from the viewpoint of ease of manufacture and ease of handling of the curable resin material, it may be 1,000 or more, 2,000 or more, or 3,000 or more. It may also be 15,000 or less, 10,000 or less, or 8,000 or less. The weight-average molecular weight (Mw) of the prepolymer (A2) may be in the range of 1,000 to 15,000.

[0042] The phosphorus atom-containing compound (B) (hereinafter sometimes referred to as "compound (B)") includes, for example, various compounds known as phosphorus-based flame retardants. Compound (B) may be used alone or in combination of two or more types. Examples of inorganic compounds among compound (B) include red phosphorus; ammonium phosphate such as monoammonium phosphate, diammonium phosphate, triammonium phosphate, and polyammonium phosphate; inorganic nitrogen-containing phosphorus compounds such as phosphate amides; phosphoric acid; phosphine oxide, etc.

[0043] Examples of organic compounds among compound (B) include aromatic phosphate esters, monosubstituted phosphonic acid diesters, disubstituted phosphinic acid esters, metal salts of disubstituted phosphinic acids, organic nitrogen-containing phosphorus compounds, cyclic organophosphorus compounds, and phosphorus-containing phenolic resins.

[0044] Examples of aromatic phosphate esters include compounds represented by the following general formula (2) and compounds represented by the following general formula (3).

[0045]

[0046] [R in general formula (2)] ５ Each of these is an aliphatic hydrocarbon group having 1 to 4 carbon atoms. Each of these is an integer from 0 to 5.

[0047]

[0048] [R in general formula (3)] ６ Each of these is an aliphatic hydrocarbon group with 1 to 4 carbon atoms. Each of these is an integer from 0 to 5. Ar １ Ar２ Each of these independently represents an arylene group. X is a directly bonded or aliphatic hydrocarbon group with 1 to 4 carbon atoms. c is 0 or 1.

[0049] R in general formula (2) ５ Each of these is an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and each of these is an integer from 0 to 5. Examples of aliphatic hydrocarbon groups having 1 to 4 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and t-butyl groups; and polymerizable unsaturated bond-containing groups such as vinyl and allyl groups. Specific examples of compounds represented by general formula (2) include triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyldiphenyl phosphate, and cresyldi-2,6-xylenyl phosphate.

[0050] R in general formula (3) ６ Each of these is an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and each of these is an integer from 0 to 5. Examples of aliphatic hydrocarbon groups having 1 to 4 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and t-butyl groups; and polymerizable unsaturated bond-containing groups such as vinyl and allyl groups. Among these, R is used because it results in a curable resin material with superior flame retardancy. ６ It is preferable that b is a methyl group. Also, b is preferably 0, 1, or 2, and more preferably 2.

[0051] Ar in general formula (3) １ Ar ２Each of these independently represents an arylene group. Examples of arylene groups include phenylene groups, naphthylene groups, and structural sites having one or more substituents on their aromatic rings. Examples of substituents on the aromatic rings include aliphatic hydrocarbon groups having 1 to 4 carbon atoms, specifically alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and t-butyl groups; and polymerizable unsaturated bond-containing groups such as vinyl and allyl groups. In general formula (3), X is a direct bond or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and c is 0 or 1. Among these, Ar is used because it results in a curable resin material with superior flame retardancy. １ Ar ２ It is preferable that all of these are phenylene groups. Furthermore, it is preferable that X is directly bonded and that c is 1.

[0052] Specific examples of compounds represented by general formula (3) include, for example, resorcinol bis(diphenyl phosphate), 1,3-phenylene bis(diphenyl phosphate), 1,3-phenylene bis(di-2,6-xylenyl phosphate), 4,4'-bis(2,6-xylenyl phosphate)biphenyl, and bisphenol A-bis(diphenyl phosphate).

[0053] Among the compounds represented by general formula (3), those represented by the following structural formula (3-1) are preferred.

[0054] Examples of monosubstituted phosphonic acid diesters include divinyl phenylphosphonate, diallyl phenylphosphonate, and bis(1-butenyl) phenylphosphonate. Examples of disubstituted phosphinic acid esters include phenyl diphenylphosphinate and methyl diphenylphosphinate.

[0055] Examples of metal salts of disubstituted phosphinic acids include metal salts of dialkylphosphinic acid, diallylphosphinic acid, divinylphosphinic acid, and diarylphosphinic acid. These metal salts include lithium salts, sodium salts, potassium salts, calcium salts, magnesium salts, aluminum salts, titanium salts, and zinc salts.

[0056] Examples of organic nitrogen-containing phosphorus compounds include phosphazene compounds such as bis(2-allylphenoxy)phosphazene and dicresylphosphazene; melamine phosphate; melamine pyrophosphate; melamine polyphosphate; and melamine polyphosphate.

[0057] Examples of cyclic organophosphorus compounds include 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (HCA), 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (HCA-HQ), compounds represented by the following general formula (4), and compounds having both a phosphazene structure and a biphenyl structure.

[0058]

[0059] [R in general formula (4)] ７ Each of these is an aliphatic hydrocarbon group with 1 to 4 carbon atoms. Each of these is an integer from 0 to 5. ３ Ar ４ Each of these independently represents an arylene group. Y is either a direct bond or an aliphatic hydrocarbon group with 1 to 4 carbon atoms. e is 0 or 1.

[0060] R in general formula (4) ７ Each of these is an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and d is 0 or an integer from 1 to 5. Examples of aliphatic hydrocarbon groups having 1 to 4 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and t-butyl groups; and polymerizable unsaturated bond-containing groups such as vinyl and allyl groups. In particular, it is preferable that d is 0 because it results in a curable resin material with superior flame retardancy.

[0061] Ar in general formula (4) ３ Ar ４ Each of these independently represents an arylene group. Examples of arylene groups include phenylene groups, naphthylene groups, and structural sites having one or more substituents on their aromatic rings. Examples include aliphatic hydrocarbon groups having 1 to 4 carbon atoms, specifically alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and t-butyl groups; and polymerizable unsaturated bond-containing groups such as vinyl and allyl groups. In general formula (4), Y is a direct bond or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and e is 0 or 1. Among these, Ar is preferred because it results in a curable resin material with superior flame retardancy. ３ Ar ４ It is preferable that both are phenylene groups. Furthermore, it is preferable that Y is directly bonded and e is 1.

[0062] Among the compounds represented by general formula (4), those represented by the following structural formula (4-1) are preferred.

[0063] In a compound having a phosphazene structure and a biphenyl structure, the phosphazene structure has a structure in which a phosphorus atom and a nitrogen atom are bonded by a double bond. The -N=P- bond may be present in one or more molecules of the compound, for example, 1 to 20, 2 to 10, or 3 to 8. A compound having a phosphazene structure and a biphenyl structure may, for example, be a compound containing a structure represented by the following general formula (5).

[0064]

[0065] [R in general formula (5)] ８ Each of these is independently a hydrogen atom, a halogen atom, or a monovalent organic group, and R ８ At least one of them is a group having a biphenyl structure, or two R ８ This forms a cyclic structure having a biphenyl structure. f is an integer from 1 to 20.

[0066] Two Rs in general formula (5) ８Each of these is independently a hydrogen atom, a halogen atom, or a monovalent organic group, and R ８ At least one of them is a group having a biphenyl structure, or two R ８ This forms a cyclic structure having a biphenyl structure. Examples of monovalent organic groups include substituted or unsubstituted alkyl groups having 1 to 30 carbon atoms, substituted or unsubstituted alkoxy groups having 1 to 30 carbon atoms, substituted or unsubstituted aryl groups having 6 to 30 carbon atoms, substituted or unsubstituted aryloxy groups having 6 to 30 carbon atoms, substituted or unsubstituted aralkyl groups having 6 to 30 carbon atoms, substituted or unsubstituted aralkyloxy groups having 6 to 30 carbon atoms, or groups having a biphenyl structure. If these monovalent organic groups have substituents, the substituents are preferably aliphatic hydrocarbon groups or aromatic hydrocarbon groups. The group having a biphenyl structure may have 12 to 30 carbon atoms, 12 to 20 carbon atoms, or 12 to 16 carbon atoms.

[0067] In general formula (5), f is an integer between 1 and 20. f may also be an integer between 2 and 10, or an integer between 3 and 8.

[0068] The phosphazene structure may be either a linear phosphazene structure or a cyclic phosphazene structure, but from the viewpoint of thermal stability in the cured product of the curable resin material, it is preferable to have a cyclic phosphazene structure. That is, a compound having a phosphazene structure and a biphenyl structure is preferably a compound having a cyclic phosphazene structure and a biphenyl structure. A compound having a cyclic phosphazene structure and a biphenyl structure may, for example, be a compound containing a structure represented by the following general formula (6).

[0069]

[0070] [R in general formula (6)] ８ This is equivalent to the one in general formula (5). g is an integer between 3 and 8.

[0071] In compounds having a phosphazene structure and a biphenyl structure, the biphenyl structure may be included in the compound as a biphenyl group or a biphenylene group (biphenyldiyl group). The biphenylene group and the biphenylene group may each be unsubstituted or substituted. The substituent is preferably an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and the number of carbon atoms of the substituent may be 1 to 30, 1 to 12, 1 to 8, or 1 to 4. For example, the substituent is R, which will be described later. ９ The following may be listed. One or more biphenyl structures may be included in one molecule of a compound having both a phosphazene structure and a biphenyl structure.

[0072] Compounds having a phosphazene structure and a biphenyl structure may be compounds in which the phosphorus atom of the phosphazene structure and the carbon atom of the biphenyl structure are directly bonded, or bonded via a C1-C4 alkylene group, a C1-C4 alkylene oxy group, or an oxygen atom. In one example, it is preferable that the phosphorus atom of the phosphazene structure and the carbon atom of the biphenyl structure are directly bonded. In another example, it is preferable that the phosphorus atom of the phosphazene structure and the carbon atom of the biphenyl structure are bonded via a methylene group or an oxygen atom, preferably via an oxygen atom. Examples include a biphenyl group, a biphenylene group, a biphenyl oxy group, and a biphenylene oxy group.

[0073] A compound having both a phosphazene structure and a biphenyl structure may have one biphenyl group directly or via a linking group bonded to one phosphorus atom in a -N=P- bond of the phosphazene structure. Alternatively, one biphenylene group may form a cyclic structure and be directly or via a linking group bonded to one phosphorus atom in a -N=P- bond of the phosphazene structure. A compound having both a phosphazene structure and a biphenyl structure may, for example, have a structure represented by the following general formula (7).

[0074]

[0075] [R in general formula (7)] ９Each of these is independently a halogen atom, a C1-C20 alkyl group, a C1-C20 alkoxy group, a C6-C20 aryl group, a C6-C20 aryloxy group, a C6-C20 aralkyl group, or a C6-C20 aralkyloxy group. Each of these is independently 0 or an integer from 1 to 4.

[0076] R in general formula (7) ９ Each of these is independently a halogen atom, a C1-C20 alkyl group, a C1-C20 alkoxy group, a C6-C20 aryl group, a C6-C20 aryloxy group, a C6-C20 aralkyl group, or a C6-C20 aralkyloxy group. ９ The group may be an alkyl group, alkoxy group, aryl group, aryloxy group, aralkyl group, or aralkyloxy group having 20 or fewer carbon atoms, 12 or fewer carbon atoms, or 4 or fewer carbon atoms, and may be a methyl group or an ethyl group.

[0077] In general formula (7), each h is independently 0 or an integer from 1 to 4. At least one of the two h in the formula may be 0, and both may be 0. That is, it is preferable that the biphenyl structure is unsubstituted.

[0078] In compounds having a phosphazene structure and a biphenyl structure, the binding position between the biphenyl structure and the phosphazene structure is not particularly limited, but may be at positions 2-4 and 2'-4' of the biphenyl structure, or at positions 2 and 2'.

[0079] Specifically, a compound having a phosphazene structure and a biphenyl structure may have a structure represented by the following general formula (8).

[0080]

[0081] The compound having a phosphazene structure and a biphenyl structure is preferably a cyclic phosphazene represented by the following formula (9), and more preferably a cyclic phosphazene represented by the following formula (10).

[0082]

[0083] [The g in general formula (9) is equivalent to the one in general formula (6). R９ And h are equivalent to those in general formula (7).

[0084]

[0085] [The 'g' in general formula (10) is equivalent to the 'g' in general formula (6).]

[0086] In general formula (9), the bonding positions of the biphenyl structure and the phosphazene structure are not particularly limited, but may be at positions 2-4 and 2'-4' of the biphenyl structure, or at positions 2 and 2'.

[0087] In the examples described above, the structure consists of one -P=N- bond and one group having a biphenyl structure repeated; however, compounds having both a phosphazene structure and a biphenyl structure may also contain -P=N- bonds that do not have a group having a biphenyl structure.

[0088] A compound having a phosphazene structure and a biphenyl structure may be, for example, a compound represented by the following general formula (11).

[0089]

[0090] [R in general formula (11)] ８ This is equivalent to the one in general formula (5).

[0091] In general formula (11), R ８ This is equivalent to the one in general formula (5). Specifically, R ８ Each is independently a hydrogen atom, a halogen atom, or a monovalent organic group, and multiple R ８ At least one of them is a group having a biphenyl structure, or two adjacent R ８ This may form a cyclic structure having a biphenyl structure. For example, two R atoms bonded to one phosphorus atom ８ This may form a cyclic structure having a biphenyl structure. For example, two R atoms bonded to three phosphorus atoms in one molecule ８ Each of these may form a cyclic structure having a biphenyl structure. Furthermore, two R atoms bonded to one phosphorus atom ８The structure that forms a cyclic structure having a biphenyl structure may be the structure represented by the above general formula (9) or general formula (10). ８ If it is a monovalent organic group, it may be one of those described in general formula (5) above.

[0092] Examples of commercially available compounds (B) include, for example, "CDP" (cresyl diphenyl phosphate), "TCP" (tricresyl phosphate), "TPP" (triphenyl phosphate), "TXP" (trixylenyl phosphate), "DAIGUARD-580", "DAIGUARD-850", "DAIGUARD-1000", "PX-110" (cresyl di-2,6-xylenyl phosphate), "CR-733S" (1,3-phenylenebis(diphenyl phosphate)), and "CR-741" (bisphenol A-bisphenol A). (Diphenyl phosphate)), "PX-200" (1,3-phenylenebis(di-2,6-xylenyl phosphate)), "PX-202"; Sanko Co., Ltd.'s "HCA" (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), "HCA-HQ" (10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), "HCA-HQ-HS", "M-Ester", "ME-P8", "PSMS-11"; Clariant Chemicals Co., Ltd.'s "EXOLIT Examples include "AP-422", "EXOLIT AP-423", "EXOLIT AP-462", "EXOLIT OP-930", "EXOLIT OP-935", "EXOLIT RP-607", "EXOLIT RP-6500", "EXOLIT RP-6520"; "SPB-100" manufactured by Otsuka Chemical Co., Ltd.; "FX-305" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "Mosaflam 585" manufactured by UFC Corporation; and "Rabitol FP-72 (TP)" manufactured by Fushimi Pharmaceutical Co., Ltd.

[0093] Among the compounds (B), one or more selected from the group consisting of the compounds represented by general formula (3), general formula (4), and general formula (5) are preferred because they exhibit particularly excellent flame retardancy when combined with resin (A). More specifically, one or more selected from the group consisting of the compounds represented by structural formula (3-1), structural formula (4-1), and general formula (10) are preferred. The proportion of these compounds in the total compound (B) may be 50% by mass or more, 80% by mass or more, 90% by mass or more, or 100% by mass.

[0094] The content of compound (B) in the curable resin material is not particularly limited, but may be adjusted, for example, by the content of phosphorus atoms relative to the total mass of resin components in the curable resin material. Specifically, the content of phosphorus atoms in compound (B) may be 0.1 parts by mass or more, 0.5 parts by mass or more, or 1 part by mass or more, per 100 parts by mass of the total of resin (A), compound (B), compound (C) used optionally as described later, other thermosetting compounds, and elastomer in the curable resin material. Alternatively, it may be 20 parts by mass or less, 10 parts by mass or less, or 5 parts by mass or less. The content of compound (B) in the curable resin material may be such that the content of phosphorus atoms is in the range of 0.1 to 20 parts by mass per 100 parts by mass of the total of resin (A), compound (B), compound (C) used optionally as described later, other thermosetting compounds, and elastomer in the curable resin material.

[0095] The curable resin material may contain other components besides the resin (A) and the phosphorus atom-containing compound (B) as needed. Examples of other components include polymerizable group-containing compounds (C) other than the resin (A) (hereinafter sometimes referred to as "compound (C)"), other thermosetting compounds having reactive groups other than polymerizable groups, elastomers, fillers, curing accelerators, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, pigments, colorants, lubricants, solvents, etc. Each of the other components may be used alone or in combination of two or more types.

[0096] Specific examples of compound (C) include, for example, compounds having a maleimide group, polyarylene ether compounds having a polymerizable group, aromatic compounds having a vinyl group, and triallyl isocyanurates.

[0097] Examples of compounds having maleimide groups include bismaleimide compounds having two maleimide groups and maleimide resins.

[0098] Specific examples of bismaleimide compounds include, for example, N,N'-ethylenebismaleimide, N,N'-hexamethylenebismaleimide, N,N'-(1,3-phenylene)bismaleimide, N,N'-[1,3-(2-methylphenylene)]bismaleimide, N,N'-[1,3-(4-methylphenylene)]bismaleimide, N,N'-(1,4-phenylene)bismaleimide, bis(4-maleimidophenyl)methane, bis(3-methyl-4-maleimidophenyl)methane, and 3,3'-dimethyl-5,5'-die Tyl-4,4'-diphenylmethanebismaleimide, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, bis(4-maleimidophenyl)sulfide, bis(4-maleimidophenyl)ketone, bis(4-maleimidocyclohexyl)methane, 1,4-bis(4-maleimidophenyl)cyclohexane, 1,4-bis(maleimidomethyl)cyclohexane, 1,4-bis(maleimidomethyl)benzene, 1,3-bis(4-maleimidophenoxy)benzene, 1,3-bis(3- Maleimidophenoxy)benzene, bis[4-(3-maleimidophenoxy)phenyl]methane, bis[4-(4-maleimidophenoxy)phenyl]methane, 1,1-bis[4-(3-maleimidophenoxy)phenyl]ethane, 1,1-bis[4-(4-maleimidophenoxy)phenyl]ethane, 1,2-bis[4-(3-maleimidophenoxy)phenyl]ethane, 1,2-bis[4-(4-maleimidophenoxy)phenyl]ethane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]propane , 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]butane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]butane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 4,4-bis(3-maleimidophenoxy)biphenyl, 4,4-bis(4-maleimidophenoxy)biphenyl, bis[4-(3-maleimidophenoxy)phenyl]ketone, bis[4-(4-maleimidophenoxy)phenyl]ketone, bis(4-maleimidophenoxy)disulfide, bis[4-(3-maleimidophenoxy)phenyl]sulfide, bis[4-(4-maleimidophenoxy)phenyl]sulfide, bis[4-(3-maleimidophenoxy)phenyl ] sulfoxide, bis[4-(4-maleimidophenoxy)phenyl] sulfoxide, bis[4-(3-maleimidophenoxy)phenyl] sulfone, bis[4-(4-maleimidophenoxy)phenyl] sulfone, bis[4-(3-maleimidophenoxy)phenyl] ether, bis[4-(4-maleimidophenoxy)phenyl] ether, 1,4-bis[4-(4-maleimidophenoxy)-α,α-dimethicone Rubenzyl]benzene, 1,3-bis[4-(4-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(4-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene Examples include 1,3-bis[4-(4-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, and aromatic bismaleimide compounds having an indane skeleton.

[0099] Specific examples of maleimide resins include, for example, polyphenylmethane maleimide, maleimide resins having an indan skeleton, and biphenyl aralkyl type maleimide resins.

[0100] Maleimide resins having an indan skeleton include, for example, those represented by the following general formula (12).

[0101] [R in general formula (12)] １０[where i is a hydrogen atom or a methyl group, and i is an integer greater than or equal to 1.]

[0102] Examples of biphenylaralkyl-type maleimide resins include those represented by the following general formula (13).

[0103]

[0104] [In general formula (13), j is an integer greater than or equal to 1.]

[0105] Regarding polyarylene ether compounds having polymerizable groups, the arylene group is not particularly limited and examples include phenylene groups, naphthylene groups, and structures in which one or more alkyl groups, alkyloxy groups, halogen atoms, etc., are substituted on the aromatic carbons thereof. Examples of polymerizable groups include vinyl groups, vinyloxy groups, allyl groups, allyloxy groups, (meth)acryloyl groups, (meth)acryloyloxy groups, vinylbenzyl groups, vinylbenzyloxy groups, etc. Polyarylene ether compounds having polymerizable groups may have structural parts other than the polyarylene ether structure. Specifically, they may have acrylic polymerization sites, (poly)urethane sites, (poly)ester sites, etc., in the molecular chain. The number of polymerizable groups in one molecule of a polyarylene ether compound is not particularly limited, nor is the substitution position of the polymerizable groups particularly limited. For example, a polyarylene ether compound may have polymerizable groups at the molecular end, or it may have polymerizable groups at both ends.

[0106] Specific examples of polyarylene ether compounds having polymerizable groups include, for example, the compound represented by the following general formula (14).

[0107]

[0108] [In general formula (14), R １１ R is a hydrogen atom or a methyl group. １２ [This group is either a vinylbenzyl group, an acryloyl group, or a methacryloyl group. k and l are integers greater than or equal to 1. Z is a divalent organic group.]

[0109] In general formula (14), Z is a divalent organic group, and its specific structure is not particularly limited, but examples include hydrocarbon groups having 1 to 6 carbon atoms, halogenated hydrocarbon groups, oxygen atoms, sulfur atoms, carbonyl groups, sulfonyl groups, etc.

[0110] The molecular weight of the polyarylene ether compound having polymerizable groups is not particularly limited, but for example, the number average molecular weight (Mn) may be in the range of 1,000 to 5,000.

[0111] Aromatic compounds having a vinyl group include, for example, styrene, divinylbenzene, 1,2-bis(4-vinylphenyl)ethane, and compounds represented by the following general formula (15).

[0112]

[0113] [In general formula (15), m is an integer greater than or equal to 1.]

[0114] When the curable resin material contains compound (C), the ratio of resin (A) to compound (C) is arbitrary. For example, the ratio of resin (A) to the total mass of both may be 10% by mass or more, 20% by mass or more, or 30% by mass or more. It may also be 99% by mass or less, or 95% by mass or less. The ratio of resin (A) to the total mass of resin (A) and compound (C) may be in the range of 10 to 99% by mass, for example.

[0115] Other thermosetting compounds include, for example, epoxy resins, phenolic resins, cyanate resins, benzoxazine resins, oxetane resins, amino resins, silicone resins, triazine resins, and melamine resins.

[0116] Examples of elastomers include polyether-based elastomers, styrene-based elastomers, conjugated diene-based elastomers, urethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, acrylic-based elastomers, and silicone-based elastomers.

[0117] Both organic and inorganic fillers can be used as fillers, but inorganic fillers are preferred. Examples of inorganic fillers include silica (SiO₂). ２), alumina (Al ２ O ３ Examples include titanium dioxide, barium titanate, strontium titanate, potassium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, aluminum borate, silicon carbide, mica, beryllia, clay, and talc. Among these, silica is preferred from the viewpoint of dielectric properties. The type of silica is not particularly limited and may be crystalline silica or amorphous silica, and may be natural silica or synthetic silica. The method of producing synthetic silica is also not particularly limited and may be wet silica such as colloidal silica, fumed silica (dry silica), or fused silica. The shape of silica is also not particularly limited and may be spherical silica, crushed silica, solid silica, porous silica, or hollow silica. Of these, spherical silica is preferred in that it becomes a curable resin material with excellent fluidity. Hollow silica is also preferred in that the dielectric constant of the cured product is lower.

[0118] The shape and size of the filler are not particularly limited. The average particle diameter of the filler may be, for example, 0.01 to 20 μm, or 0.1 to 10 μm. Here, the average particle diameter of the filler is the particle diameter at the point corresponding to 50% of the cumulative value in the volume-based particle distribution obtained by laser diffraction scattering.

[0119] If the curable resin material contains a filler, the amount of filler added may be in the range of 50 to 500 parts by mass per 100 parts by mass of the total of the curable component and elastomer in the curable resin material.

[0120] As a curing accelerator, for example, a radical polymerization initiator can be used. The radical polymerization initiator may be a thermal radical polymerization initiator or a photoradical polymerization initiator, but a thermal radical polymerization initiator is preferred. Specific examples of polymerization initiators include azo polymerization initiators and organic peroxide polymerization initiators. Examples of azo polymerization initiators include 2,2'-azobis(2,4,4-trimethylpentane), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 1,1'-azobis(cyclohexane-1-carbonitride), and dimethyl-1,1'-azobis(1-cyclohexanecarboxylate). Examples include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylpropanenitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 4,4'-azobis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl4-cyanopentanoate). Examples of organic peroxide polymerization initiators include dicumyl peroxide, dibenzoyl peroxide, 2-butanone peroxide, t-butyl perbenzoate, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyn-3, α,α'-di(t-butylperoxy)diisopropylbenzene, and t-butyl hydroperoxide.

[0121] The content of the curing accelerator in the curable resin material is not particularly limited, but for example, it may be 0.05 parts by mass or more, 0.1 parts by mass or more, or 0.5 parts by mass or more, per 100 parts by mass of the total of the resin (A), optionally used compound (C), other thermosetting compounds, and elastomer in the curable resin material. Alternatively, it may be 10 parts by mass or less, 8 parts by mass or less, or 5 parts by mass or less. The content of the curing accelerator may be in the range of 0.05 to 10 parts by mass per 100 parts by mass of the total of the resin (A), optionally used compound (C), other thermosetting compounds, and elastomer in the curable resin material.

[0122] The curable resin material may be solvent-free or may contain a solvent. The solvent can adjust the viscosity of the curable resin material and further improve its coating properties. Organic solvents are preferred as the solvent.

[0123] Examples of organic solvents include alcohol-based solvents such as ethanol, propanol, butanol, methyl cellosolve, ethylene glycol monobutyl ether, and propylene glycol monomethyl ether; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based solvents such as tetrahydrofuran; aromatic hydrocarbon-based solvents such as toluene, xylene, and mesitylene; nitrogen-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; sulfur-containing solvents such as dimethyl sulfoxide; and ester-based solvents such as γ-butyrolactone.

[0124] If the curable resin material contains a solvent, the solid content of the curable composition may be, for example, in the range of 30 to 95% by mass.

[0125] The method for producing a curable resin material is not particularly limited. One example of a method for producing a curable resin material is to add and mix a resin (A), a phosphorus atom-containing compound (B), and any optional components as needed. When mixing, the resin (A), phosphorus atom-containing compound (B), and any optional components may be mixed as they are, or they may be dissolved or dispersed in a solvent before mixing. The mixing order of each component, temperature, time, and other conditions are not particularly limited and may be adjusted as appropriate according to the type of raw materials, production scale, production equipment, etc.

[0126] [Prepreg] According to one embodiment, a prepreg containing a curable resin material or a semi-cured product of a curable resin material can be provided. This prepreg can be formed, for example, using a curable resin material and a fibrous substrate. With respect to the semi-cured product of the curable resin material, in this disclosure, the B-stage state in JIS K 6800 (1985) can be cited as one indicator of the semi-cured state. The prepreg may contain, for example, a curable resin material or a semi-cured product of a curable resin material and a fibrous substrate such as a sheet-like fibrous substrate. In the prepreg, the curable resin material may be in an uncured state, or it may be in a partially or entirely semi-cured state.

[0127] A prepreg can be obtained, for example, by impregnating a fibrous substrate with a curable resin material and drying the fibrous substrate impregnated with the curable resin material. Drying is preferably carried out at a temperature above which volatile components such as solvents that may be contained in the curable resin material are removed, and may also be carried out at a temperature above which the curable components contained in the curable resin material are partially cured, depending on the application. Furthermore, it is preferable that the drying is adjusted so that the thermosetting resin contained in the curable resin material is not completely cured. From this viewpoint, the drying temperature may be, for example, 80 to 200°C, and the drying time may be, for example, 1 to 30 minutes, depending on the drying temperature, drying equipment, and its scale.

[0128] The fibrous base material may be woven, knitted, or nonwoven fabric. The fibrous base material may be provided in the form of chopped strand mat, roving, etc. The fiber material may be either inorganic or organic fiber. Examples of inorganic fibers include glass fiber and carbon fiber. Examples of glass fiber include E glass, NE glass, D glass, S glass, and Q glass. Examples of organic fibers include polyimide, polyester, and tetrafluoroethylene. The fibrous base material may use one type of fiber alone, or two or more types in combination. From the viewpoint of dielectric properties and heat resistance, inorganic fibers are preferred for the fibrous base material, and glass fibers are more preferred.

[0129] The fibrous substrate can be appropriately selected depending on the application of the prepreg, but a sheet-like fibrous substrate is preferred. The sheet-like fibrous substrate may be, for example, various sheet-like fibrous substrates used in known laminates for electrical insulating materials. The thickness of the sheet-like fibrous substrate is not particularly limited, but for example, 0.01 to 0.1 mm is preferred. Here, the thickness is determined by measuring the thickness at five points at equal distances across the entire surface of the sheet-like fibrous substrate and taking the arithmetic mean of the five points.

[0130] [Resin Film] According to one embodiment, a resin film can be provided that includes a curable resin material or a semi-cured product of a curable resin material. The resin film can be obtained, for example, by coating a material to be coated with a curable resin material and drying or semi-curing it. Drying or semi-curing can be carried out in the same manner as the manufacturing method of the prepreg described above. After drying the resin film on the material to be coated, the product may be provided as a combination of the resin film and the material to be coated. For example, in this method, the resin film can be provided as a surface protective film, an interlayer insulating film, etc., on a printed circuit board. In another method, after drying the resin film on the material to be coated, the resin film may be peeled off the material to provide the resin film as a product.

[0131] The material to be coated may be either an inorganic or organic substrate, and examples include glass substrates, metal foils, metal plates and other metal substrates, plastic plates, plastic films and other plastic substrates, paper substrates, and even fibrous substrates as described in the prepreg section above. In order to peel the resin film from the material to be coated and provide it, a material to be coated that has a release layer formed on its surface may be used.

[0132] [Metal-clad laminate] According to one embodiment, a metal-clad laminate containing a cured product of a curable resin material and a metal foil can be provided. With respect to the cured product, in this disclosure, the state of the C-stage in JIS K 6800 (1985) can be cited as one indicator of the cured product.

[0133] In a metal-clad laminate, the cured product of the curable resin material may be included as the cured product of the curable resin material itself, or it may be included in the form of a prepreg. The metal-clad laminate may include a prepreg layer and a metal foil placed on at least one surface of the prepreg layer. The prepreg layer is the cured product of the prepreg described above, and may consist of a single prepreg or multiple prepregs laminated together. Furthermore, the metal-clad laminate may have the metal foil placed on one surface of the curable resin material or the cured prepreg, or it may have the metal foil placed on both surfaces of the curable resin material or the cured prepreg. The metal-clad laminate may be manufactured by placing the metal foil on at least one surface of a single sheet-like prepreg, or it may be manufactured by laminating two or more sheet-like prepregs and placing the metal foil on at least one surface of the outermost layer of the laminate. A metal-clad laminate may be manufactured by laminating two or more sheet-like prepregs and arranging metal foil on both sides of this laminate.

[0134] The following describes a specific method for manufacturing metal-clad laminates, which involves arranging metal foil on a laminate of two or more sheet-like prepregs.

[0135] First, two or more sheet-like prepregs are laminated to obtain a laminate. In this laminate, the two or more sheet-like prepregs may be identical, or they may be partially or completely different. In the laminate, it is sufficient that at least one of the two or more sheet-like prepregs is obtained using a curable resin material according to one embodiment.

[0136] Next, a metal foil is placed on at least one surface of the laminate. The laminate with the metal foil is then heated and pressurized. This causes the sheet-like prepreg to harden, and a hardened prepreg product can be obtained. Adjacent sheet-like prepregs can also be bonded together. The heating and pressurizing conditions are not particularly limited, but for example, the temperature can be 100 to 300°C, the time 10 to 300 minutes, and the pressure 0.5 to 50 MPa. After heating and pressurizing, reheating may be performed to further harden the prepreg. In this case, the reheating temperature can be 100 to 300°C. As for the pressurizing method, for example, an autoclave molding machine, a multi-stage press machine, a multi-stage vacuum press machine, a continuous molding machine, etc., can be used.

[0137] The metal used for the metal foil is not particularly limited and can include, for example, copper, nickel, aluminum, gold, silver, platinum, molybdenum, ruthenium, tungsten, iron, titanium, chromium, and alloys containing two or more of these metal elements. Industrially, it is preferable to use elemental copper, nickel, or aluminum. By using copper as the metal foil, a copper-clad laminate can be provided.

[0138] [Printed Wiring Board] According to one embodiment, a printed wiring board including a cured product of a curable resin material can be provided. In the printed wiring board, the cured product of the curable resin material may be included as a cured product of the curable resin material itself, or may be included in a prepreg state. The printed wiring board can be manufactured using a curable resin material, a prepreg, a metal-clad laminate, or a combination thereof. For example, a printed wiring board can be provided by forming wiring by a known method using a metal-clad laminate. Details of the prepreg and the metal-clad laminate are as described above. The printed wiring board may be either a single-layer printed wiring board or a multilayer printed wiring board.

[0139] [Semiconductor Package] According to one embodiment, a semiconductor package including a printed wiring board and a semiconductor element can be provided. More specifically, for example, a semiconductor package including a printed wiring board including a cured product of a curable resin material and a semiconductor element can be provided. The semiconductor package can be manufactured, for example, by mounting a semiconductor element, a memory, etc. on a printed wiring board by a known method.

[0140] Examples of the embodiment are given below. The present invention is not limited to the following embodiments. <1> A curable resin material including a resin (A) containing an indene ring, a vinylbenzyl group, and an arylalkyl group other than the vinylbenzyl group, and a phosphorus atom-containing compound (B).

[0141] <2> The resin (A) contains two or more compounds having different structures among the compounds represented by the following general formula (1), and at least one of R １ , R ２ and R ３ in the resin is a vinylbenzyl group, and at least one of R １ , R ２ and R ３ in the resin is an arylalkyl group other than the vinylbenzyl group. The curable resin material according to <1> above.

[0142]

[0143] [In general formula (1), R １ , R ２ and R ３ are each independently a hydrogen atom, a vinylbenzyl group, or an arylalkyl group other than a vinylbenzyl group. R ４ is a hydrogen atom or a monovalent organic group, and all four R ４ may be different from each other, or two or more of the four R ４ may be the same as each other. ]

[0144] <3> The resin (A) contains two or more compounds having different structures among the compounds represented by the following general formula (1), and at least one of R １ , R ２ and R ３ present in the resin is a vinylbenzyl group, and at least one of R １ , R ２ and R ３ present in the resin is an arylalkyl group other than a vinylbenzyl group. The curable resin material according to <1> or <2> above, containing a prepolymer (A2) obtained by polymerizing a part of the vinyl groups in the resin (A1).

[0145]

[0146] [In general formula (1), R １ , R ２ and R ３ are each independently a hydrogen atom, a vinylbenzyl group, or an arylalkyl group other than a vinylbenzyl group. R ４ is a hydrogen atom or a monovalent organic group, and all four R ４ may be different from each other, or two or more of the four R ４ may be the same as each other. ]

[0147] <4> The weight average molecular weight (Mw) of the prepolymer (A2) is 3,000 or more. The curable resin material according to <3> above.

[0148] <5> The arylalkyl group other than the vinylbenzyl group has no polymerizable unsaturated bond. The curable resin material according to any one of <1> to <4> above.

[0149] <6> The curable resin material according to any one of <1> to <5> above, wherein the phosphorus atom-containing compound (B) includes one or more selected from the group consisting of a compound represented by the following structural formula (3-1), a compound represented by the following structural formula (4-1), and a compound represented by the following general formula (10).

[0150]

[0151] [In general formula (10), g is an integer between 3 and 8.]

[0152] <7> A curable resin material according to any one of <1> to <6> above, comprising a polymerizable group-containing compound (C) other than the resin (A).

[0153] <8> A prepreg comprising a curable resin material or a semi-cured product of the curable resin material described in any one of <1> to <7> above.

[0154] <9> A resin film comprising a curable resin material described in any one of <1> to <7> above, or a semi-cured product of the curable resin material.

[0155] <10> A metal-clad laminate comprising a cured product of a curable resin material described in any one of <1> to <7> above, and a metal foil.

[0156] <11> A printed circuit board comprising a cured product of the curable resin material described in any one of <1> to <7> above.

[0157] <12> A semiconductor package comprising the printed circuit board described in <11> and a semiconductor element.

[0158] <13> A semiconductor package comprising a semiconductor element and a cured product of any one of <1> to <7> above for sealing the semiconductor element.

[0159] <14> A printed circuit board comprising at least one of a surface protective film and an interlayer insulating film formed from any one of the curable resin materials described in <1> to <7> above.

[0160] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0161] Measurement Method for Weight-Average Molecular Weight (Mw) and Number-Average Molecular Weight (Mn) The weight-average molecular weight and number-average molecular weight were calculated from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The calibration curve was approximated by a cubic equation using standard polystyrene: TSK standard POLYSTYRENE (Type; A-2500, A-5000, F-20, F-80) (manufactured by Tosoh Corporation, trade name). The GPC measurement conditions are shown below.

[0162] Instrument: High-speed GPC instrument HLC-8320GPC (Tosoh Corporation, product name) Detector: Ultraviolet absorption detector UV-8320 (Tosoh Corporation, product name) Columns: Guard column; TSKgel guardcolumn Super(HZ)-M+, Column; TSKgel SuperMultipore HZ-M (2), Reference column; TSKgel SuperH-RC (2) (all Tosoh Corporation, product names) Column size: 4.6 × 20 mm (guard column), 4.6 × 150 mm (column), 6.0 × 150 mm (reference column) Eluent: Tetrahydrofuran Sample concentration: 10 mg / 1 mL Injection volume: 20 μL or 2 μL Flow rate: 0.35 mL / min Measurement temperature: 40°C

[0163] [Production of resins (A1-1) to (A1-3)] A 500 mL reaction vessel equipped with a stirrer, thermometer, reflux tubing, and nitrogen inlet was charged with the amounts shown in Table 1: indene, chloromethylstyrene (*1), α-chloro-p-xylene, tetra-n-butylammonium bromide as a phase transfer catalyst, phenothiazine as a polymerization inhibitor, and toluene as a solvent. The mixture was heated and stirred at 40°C while blowing nitrogen at a flow rate of 50 mL / min.

[0164] Next, the amount of sodium hydroxide aqueous solution (48% by mass) listed in Table 1 was added dropwise over 20 minutes, and the mixture was stirred at 60°C for 9 hours. Nitrogen was continuously blown in during the reaction. After cooling to room temperature (25°C) and neutralizing with 10% hydrochloric acid aqueous solution, the mixture was washed twice with pure water. After removing toluene by vacuum distillation, the resulting viscous liquid was washed with methanol and vacuum dried to obtain resins (A1-1) to (A1-3).

[0165] Chloromethylstyrene (*1): AGC Seimi Chemical Co., Ltd. "CMS-P", a mixture of m-isomer and p-isomer, m-isomer content approximately 50% by mass, p-isomer content approximately 50% by mass.

[0166]

[0167] [Preparation of Prepolymer (A2)] The resin (A1-1) obtained earlier and toluene were mixed in a 5 L separable flask to make a solution with a solid content of 50% by mass. The mixture was heated under a nitrogen atmosphere at 110°C ± 10°C for 5 hours to obtain the prepolymer (A2) solution. The weight-average molecular weight (Mw) of prepolymer (A2) was 5,000.

[0168] [Preparation of Compound (B1)] 432 parts by mass of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), 251 parts by mass of bis(chloromethyl)biphenyl, and 2400 parts by mass of toluene were added to a reaction vessel equipped with a stirrer, thermometer, reflux tubing, and nitrogen inlet. The reaction was then continued at 170°C for 16 hours while stirring the contents of the reaction vessel. After the reaction mixture was cooled to room temperature, hexane was added to precipitate the product, which was then filtered. The resulting white crystals were dried at 120°C to obtain the compound represented by the above structural formula (4-1). This compound is designated as Compound (B1).

[0169] [Preparation of Compound (C3)] 236.8 parts by mass of 2-bromoethylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) and 56.0 parts by mass of α,α'dichloro-p-xylene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a reaction vessel equipped with a stirrer, thermometer, reflux tubing, and nitrogen inlet, and the mixture was stirred. 14.7 parts by mass of methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), which had been melted by standing at 25°C, was added dropwise to the reaction vessel using a pipette. The reaction vessel was immersed in an oil bath, and the reaction was carried out at 130°C for 7 hours while stirring the contents of the reaction vessel. After removing the vessel from the oil bath and allowing it to cool naturally, 106.4 parts by mass of 48% NaOH aqueous solution was added dropwise to neutralize the mixture. 960 parts by mass of toluene was added and the mixture was stirred to extract the toluene-soluble components. The resulting organic layer was removed and washed five times with water. The organic layer after washing was heated under reduced pressure to remove toluene and unreacted substances by distillation, yielding 112 parts by mass (yield 65%) of an intermediate having a 2-bromoethylbenzene structure.

[0170] In a reaction vessel equipped with a stirrer, thermometer, reflux tubing, and nitrogen inlet, 110 parts by mass of the intermediate obtained earlier, 250 parts by mass of toluene, 750 parts by mass of dimethyl sulfoxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) melted by standing at 25°C, 75 parts by mass of water, and 25 parts by mass of solid sodium hydroxide (manufactured by Kanto Chemical Co., Ltd.) were added. The reaction vessel was immersed in an oil bath and reacted at 40°C for 5 hours while stirring the contents of the reaction vessel. After removing it from the oil bath and allowing it to cool naturally, 500 parts by mass of toluene was added and stirred to extract the toluene-soluble components. The obtained organic layer was removed and washed five times with 500 parts by mass of water. The washed organic layer was heated under reduced pressure to remove the solvent and 65 parts by mass (yield 75%) of compound (C3) having the structure represented by the above general formula (15) were obtained. The obtained compound (C3) had a number-average molecular weight (Mn) of 443, a weight-average molecular weight (Mw) of 451, and the value of m in the general formula (15) above was between 1 and 2.

[0171] [Examples 1-17 and Comparative Examples 1 and 2] Each component was blended in the proportions shown in Tables 2-4, and the solid content was adjusted to approximately 65% ​​by mass with toluene to produce a curable resin material. For components that are solutions in Tables 2-4, the blending amounts are calculated on a solid content basis. The following evaluation tests were performed on the obtained curable resin materials. The results are shown in Tables 2-4.

[0172] The amount of compound (B) added is calculated as the phosphorus atom content relative to the total mass of resins (A1-1) to (A1-3), prepolymer (A2), compounds (B1) to (B3), and compounds (C1) to (C6).

[0173] Details of each component listed in Tables 2-4 are as follows: • Resin (A1-1): Resin (A1-1) obtained earlier • Resin (A1-2): Resin (A1-2) obtained earlier • Resin (A1-3): Resin (A1-3) obtained earlier • Prepolymer (A2): Prepolymer (A2) obtained earlier • Compound (B1): Compound (B1) obtained earlier, a phosphorus atom-containing compound represented by the above structural formula (4-1) • Compound (B2): A phosphorus atom-containing compound represented by the above structural formula (3-1) ("PX-202" manufactured by Daihachi Chemical Industry Co., Ltd.) • Compound (B3): A phosphorus atom-containing compound represented by the above general formula (10) ("Rabitol FP-72 (TP)" manufactured by Fushimi Pharmaceutical Co., Ltd.) Compound (C1): JSR Corporation's "HC-G0037", a polymerizable aromatic polyether compound. Compound (C2): JSR Corporation's "HC-G0030", a polymerizable aromatic polyether compound. Compound (C3): Compound (C3) obtained above. Compound (C4): 1,2-bis(4-vinylphenyl)ethane. Compound (C5): SABIC Corporation's "SA9000", a polyphenylene ether resin with methacryloyl groups at the terminals, number average molecular weight (Mn) 1,700. • Compound (C6): MIR-3000 manufactured by Nippon Kayaku Co., Ltd., a biphenylaralkyl type maleimide resin having the structure represented by the above general formula (13) • Compound (C7): an indane ring-containing aromatic bismaleimide compound having the structure represented by the above general formula (12) • Curing accelerator (1): Perbutyl P manufactured by NOF Corporation, α,α'-di(t-butylperoxy)diisopropylbenzene • Curing accelerator (2): Perhexine 25B manufactured by NOF Corporation, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexine-3 • Filler (1): Molten spherical silica, average particle size (D ５０ ) 0.5 μm Filler (2): Average particle diameter (D ５０ ) 2.0 μm hollow silica

[0174] [Prepreg Preparation] A curable resin material was impregnated and coated onto glass cloth conforming to IPC standard #1078, and then heated and dried at 120°C for 10 minutes to obtain a prepreg. The solid content of the prepreg derived from the curable resin material was approximately 80% by mass.

[0175] [Preparation of Double-Sided Copper-Clad Laminates] Two layers of the obtained prepreg were prepared, and thirteen layers were prepared. On both sides of these, 18 μm thick electrolytic copper foil (SI-VSP-18, manufactured by Mitsui Mining & Smelting Co., Ltd.) was laid with the matte side facing the prepreg. This was then subjected to a load of 3 kg / cm². ２ A double-sided copper-clad laminate was obtained by heating and pressurizing under vacuum pressing conditions at 230°C for 80 minutes.

[0176] [Evaluation of Flame Retardancy] The double-sided copper-clad laminate (with 13 layers of prepreg) obtained earlier was immersed in the copper etching solution (*3) described below to remove the copper foil, and five pieces measuring 125 mm in length and 13 mm in width were prepared as test specimens. A vertical combustion test in accordance with UL94-V was performed using these test specimens. Specifically, the upper end of the test specimen was held, and the flame of a gas burner was applied vertically to the lower end of the test specimen for 10 seconds, after which the flame of the gas burner was removed. After confirming that the flame had gone out, the flame of the gas burner was applied vertically to the lower end of the test specimen again for 10 seconds. The burning time after the flame was removed was measured. The first and second burning times of each test specimen were added together to calculate the average burning time for the five test specimens, and they were evaluated according to the following criteria: A: 30 seconds or less B: 31 seconds or more and 60 seconds or less C: 61 seconds or more

[0177] (*3) Copper etching solution: 10% by mass solution of ammonium persulfate (manufactured by Mitsubishi Gas Chemical Company, Inc.)

[0178] [Evaluation of Dielectric Properties] A double-sided copper-clad laminate (with two layers of prepreg) was immersed in a copper etching solution (*3) to remove the copper foil from both sides, and a 100 mm x 40 mm test specimen was prepared. The obtained test specimen was dried at 105°C for 1 hour, and then left to stand for 24 hours in an ambient temperature of 24.2°C and a humidity of 54% RH. Next, the dielectric constant (Dk) and dielectric loss tangent (Df) were measured in the 10 GHz band at an ambient temperature of 25°C in accordance with the split-post dielectric resonator method. The measuring instrument used was the "PNA Network Analyzer N5222B" from agilent technologies.

[0179]

[0180]

[0181]

[0182] As shown in Tables 2 to 4, the curable resin materials of Examples 1 to 17, which contained resin (A) and compound (B), exhibited excellent flame retardancy in the cured product. On the other hand, the curable resin materials of Comparative Examples 1 and 2, which did not contain resin (A) but contained compound (B) and compound (C), exhibited inferior flame retardancy in the cured product compared to the curable resin materials of the Examples.

[0183] The disclosures of this application relate to the subject matter described in Japanese Patent Application No. 2024-156992, filed on 10 September 2024, and the subject matter described in Japanese Patent Application No. 2024-217508, filed on 12 December 2024, the disclosures of which are incorporated herein by reference.

Claims

1. A curable resin material comprising a resin (A) containing an indene ring, a vinylbenzyl group, and an arylalkyl group other than a vinylbenzyl group, and a phosphorus atom-containing compound (B).

2. The resin (A) contains two or more compounds having different structures among the compounds represented by the following general formula (1), and R present in the resin １ , R ２ and R ３ Among them, at least one is a vinylbenzyl group, and R present in the resin １ , R ２ and R ３ The curable resin material according to claim 1, comprising a resin (A1) in which at least one of them is an arylalkyl group other than a vinylbenzyl group. [In the general formula (1), R １ , R ２ and R ３ are each independently a hydrogen atom, a vinylbenzyl group, or an arylalkyl group other than a vinylbenzyl group. R ４ is a hydrogen atom, a halogen atom, or a monovalent organic group, and all four R ４ may be different from each other, and two or more of the four R ４ may be the same as each other.] 3. The resin (A) contains two or more compounds represented by the following general formula (1) that have different structures from each other, and R present in the resin １ , R ２ and R ３ At least one of them is a vinylbenzyl group, and R present in the resin １ , R ２ and R ３ The curable resin material according to claim 1, comprising a prepolymer (A2) obtained by polymerizing a portion of the vinyl groups in a resin (A1) in which at least one of the groups is an arylalkyl group other than a vinylbenzyl group. [In general formula (1), R １ , R ２ and R ３ These are, independently, a hydrogen atom, a vinylbenzyl group, and an arylalkyl group other than a vinylbenzyl group. ４ is a hydrogen atom, a halogen atom, or a monovalent organic group, and has four R ４ All of them may be different from each other, and there are four R's. ４ Two or more of them may be identical.

4. The curable resin material according to claim 3, wherein the weight-average molecular weight (Mw) of the prepolymer (A2) is 3,000 or more.

5. The curable resin material according to claim 1, wherein the arylalkyl group other than the vinylbenzyl group does not have a polymerizable unsaturated bond.

6. The curable resin material according to claim 1, wherein the phosphorus atom-containing compound (B) comprises one or more compounds selected from the group consisting of compounds represented by the following structural formula (3-1), compounds represented by the following structural formula (4-1), and compounds represented by the following general formula (10). [In general formula (10), g is an integer between 3 and 8.] 7. The curable resin material according to claim 1, comprising a polymerizable group-containing compound (C) other than the resin (A).

8. A prepreg comprising a curable resin material according to any one of claims 1 to 7 or a semi-cured product of the curable resin material.

9. A resin film comprising a curable resin material according to any one of claims 1 to 7 or a semi-cured product of the curable resin material.

10. A metal-clad laminate comprising a cured product of a curable resin material according to any one of claims 1 to 7 and a metal foil.

11. A printed circuit board comprising a cured product of a curable resin material according to any one of claims 1 to 7.

12. A semiconductor package comprising a printed circuit board according to claim 11 and a semiconductor element.

13. A semiconductor package comprising a semiconductor element and a cured product of a curable resin material according to any one of claims 1 to 7 for sealing the semiconductor element.

14. A printed circuit board comprising at least one of a surface protective film and an interlayer insulating film formed from a curable resin material according to any one of claims 1 to 7.

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