Resin composition, prepreg, resin film, metal-clad laminate, printed wiring board, semiconductor package, and acenaphthene homopolymer

Abstract

A resin composition containing (A) a thermosetting resin and (B) an acenaphthene polymer having a number average molecular weight of 1,000 or more.

Description

Technical Field

[0001] The present disclosure relates to a resin composition, a prepreg, a resin film, a metal-clad laminate, a printed wiring board, a semiconductor package, and an acenaphthene homopolymer. Background Art

[0002] Metal-clad laminates represented by copper-clad laminates, prepregs that can be used for metal-clad laminates, and semiconductor packages using metal-clad laminates are used in a variety of electronic devices such as portable communication devices such as smartphones, personal computers, industrial computers, servers, large servers, routers, and portable base stations. In addition, they are also used in electronic devices installed in home appliances, automobiles, etc. Among them, for electronic communication equipment, the demand for high-speed processing of huge data has increased due to the popularization of 5G.

[0003] When processing huge amounts of data at high speed, electronic devices require substrate materials with low transmission loss in high-frequency regions, and materials with low dielectric constants and low dielectric loss tangents are required.

[0004] In addition, flame retardancy is also required for such substrate materials, and the use of phosphorus-based flame retardants in resin compositions has been studied (for example, Patent Document 1).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2004-315725 Summary of the invention

[0008] Problems to be solved by the invention

[0009] The present disclosure provides a low-sublimation resin composition for providing a product having excellent dielectric properties and flame retardancy, a prepreg, a resin film, a metal-clad laminate, a printed wiring board, and a semiconductor package using the resin composition, and an acenaphthene homopolymer.

[0010] Means for solving problems

[0011] Examples of the embodiments are given below. The present invention is not limited to the following embodiments.

[0012] One embodiment relates to a resin composition including (A) a thermosetting resin and (B) an acenaphthene polymer having a number average molecular weight of greater than or equal to 1,000.

[0013] Another embodiment relates to a prepreg formed using the resin composition.

[0014] Another embodiment relates to a resin film formed using the resin composition.

[0015] Another embodiment relates to a metal-clad laminate including a cured product of the resin composition and a metal foil.

[0016] Another embodiment relates to a metal-clad laminate formed using the prepreg and a metal foil.

[0017] Another embodiment relates to a printed wiring board including a cured product of the resin composition.

[0018] Another embodiment relates to a semiconductor package including the printed wiring board and a semiconductor element.

[0019] Another embodiment is directed to an acenaphthene homopolymer having a number average molecular weight greater than or equal to 1,000.

[0020] Effects of the Invention

[0021] According to the present disclosure, there can be provided a low-sublimation resin composition for providing a product having excellent dielectric properties and flame retardancy, a prepreg, a resin film, a metal-clad laminate, a printed wiring board, and a semiconductor package using the same, and an acenaphthene homopolymer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] [ Figure 1 ] Figure 1 This is a schematic diagram schematically showing an example of a metal-clad laminate according to an embodiment. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

[0024] In the present disclosure, the numerical range represented by "to" indicates a range including the numerical values ​​recorded before and after "to" as the minimum value and the maximum value, respectively. In the numerical ranges recorded in stages in the present disclosure, the upper limit or lower limit of a certain numerical range can be replaced by the upper limit or lower limit of another numerical range. In addition, the upper limit or lower limit of the numerical range recorded in the present disclosure can also be replaced by the value shown in the embodiments.

[0025] In the present disclosure, unless otherwise specified, each component may contain one or two or more substances corresponding to each component.

[0026] In the present disclosure, when a plurality of substances corresponding to each component are present in the resin composition, the content of each component in the resin composition refers to the total amount of the plurality of substances present in the resin composition unless otherwise specified.

[0027] In the present disclosure, unless otherwise specified, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are values ​​measured by the following measurement methods.

[0028] The weight average molecular weight and number average molecular weight are calculated by gel permeation chromatography (GPC) from a calibration curve using standard polystyrene. The calibration curve is approximated by a cubic equation using standard polystyrene: TSKstandard POLYSTYRENE (Type: A-2500, A-5000, F-20, F-80) (manufactured by Tosoh Corporation, trade name). The conditions of GPC are as follows.

[0029] Device: High-speed GPC device "HLC-8320GPC" (Tosoh Corporation, trade name)

[0030] Detector: Ultraviolet absorption detector "UV-8320" (Tosoh Corporation, trade name)

[0031] Column: Guard column: TSKgel guardcolumn Super(HZ)-M+, column: TSKgel SuperMultiporeHZ-M (2 pieces), reference column: TSKgel SuperH-RC (2 pieces) (all trade names of Tosoh Corporation)

[0032] Column size: 4.6×20mm (guard column), 4.6×150mm (column), 6.0×150mm (reference column)

[0033] Eluent: Tetrahydrofuran

[0034] Sample concentration: 10mg / 1mL

[0035] Injection volume: 20μL or 2μL

[0036] Flow rate: 0.35mL / min

[0037] Measurement temperature: 40℃

[0038] [Resin composition]

[0039] The resin composition of one embodiment of the present disclosure contains (A) a thermosetting resin and (B) an acenaphthene polymer having a number average molecular weight of 1,000 or more. Hereinafter, "(A) thermosetting resin" may be referred to as "(A) component". In addition, "(B) acenaphthene polymer having a number average molecular weight of 1,000 or more" may be referred to as "(B) acenaphthene polymer" or "(B) component".

[0040] By using the resin composition, a product with excellent dielectric properties and high flame retardancy can be provided. In addition, the resin composition has low sublimation and is not easy to become the cause of pollution of devices such as drying furnaces. Without being bound by theory, the reasons are speculated as follows. Acenaphthene has a skeleton with low polarity, so it may be possible to achieve good dielectric properties. In addition, the inventors of the present invention have also found that acenaphthene has excellent flame retardancy. It is speculated that this is because the skeleton of acenaphthene is polycyclic aromatic, so the heat of combustion is small. On the other hand, acenaphthene has high sublimation and will sublimate due to heating, which may become the cause of pollution of devices such as drying furnaces. It is speculated that by using an acenaphthene polymer having a number average molecular weight greater than or equal to 1,000 obtained by polymerizing acenaphthene in a resin composition, not only good dielectric properties and high flame retardancy can be achieved, but also low sublimation can be achieved.

[0041] <(A) Thermosetting resin>

[0042] As (A) thermosetting resin, it is not particularly limited, for example, epoxy resin, maleimide compound, phenolic resin, modified polyphenylene ether resin, polyimide resin, cyanate resin, isocyanate resin, benzoxazine resin, oxetane resin, amino resin, unsaturated polyester resin, allyl resin, dicyclopentadiene resin, silicone resin, triazine resin, melamine resin and compounds with vinyl benzyl etc. can be listed. Thermosetting resin can be polymerized and / or cured when heated in the presence of polymerization initiator etc. as required. For example, compounds with vinyl benzyl and maleimide compounds described later can be monomers, oligomers, prepolymers etc., which can also be used as (A) thermosetting resin.

[0043] (A) Component may be used alone or in combination of two or more.

[0044] The epoxy resin preferably has two or more epoxy groups in one molecule. Examples of the epoxy resin include glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, and glycidyl ester type epoxy resins.

[0045] Epoxy resin can be further classified into bisphenol epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, novolac epoxy resin, stilbene epoxy resin, naphthalene skeleton epoxy resin, biphenyl epoxy resin, xylene epoxy resin, dihydroanthracene epoxy resin, etc. for the above-mentioned various types of epoxy resin. As bisphenol epoxy resin, for example, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, etc. can be listed. As alicyclic epoxy resin, for example, dicyclopentadiene epoxy resin, etc. can be listed. As novolac epoxy resin, for example, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A novolac epoxy resin, bisphenol F novolac epoxy resin, phenol aralkyl novolac epoxy resin, biphenyl aralkyl novolac epoxy resin, etc. can be listed. Examples of the naphthalene skeleton-containing epoxy resin include naphthol novolac epoxy resins and naphthol aralkyl epoxy resins.

[0046] The epoxy resins can be used alone or in combination of two or more.

[0047] Examples of the maleimide compound include compounds having one or more N-substituted maleimide groups and derivatives thereof. For example, at least one selected from the group consisting of compounds having two or more N-substituted maleimide groups and derivatives thereof can be used.

[0048] As compounds having one or more N-substituted maleimide groups, for example, aromatic maleimide compounds, aromatic bismaleimide compounds, aromatic polymaleimide compounds, aliphatic maleimide compounds, etc. can be cited. In the present disclosure, "aromatic maleimide compounds" refer to compounds having N-substituted maleimide groups directly bonded to aromatic rings. In the present disclosure, "aromatic bismaleimide compounds" refer to compounds having two N-substituted maleimide groups directly bonded to aromatic rings. In the present disclosure, "aromatic polymaleimide compounds" refer to compounds having three or more N-substituted maleimide groups directly bonded to aromatic rings. In addition, in the present disclosure, "aliphatic maleimide compounds" refer to compounds having N-substituted maleimide groups directly bonded to aliphatic hydrocarbons.

[0049] Specific examples of the compound having one or more N-substituted maleimide groups include 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, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)ether, 1,4-bis(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- 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-maleimidophenyl)disulfide, bis[4-(3-maleimidophenoxy)phenyl]sulfide, bis[4-(4-maleimidophenoxy)phenyl]sulfide, 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-dimethylbenzyl]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 , 1,3-bis[4-(4-maleimide phenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-maleimide phenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimide phenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, polyphenylmethane maleimide, aromatic bismaleimide compounds having an indane skeleton, biphenyl aralkyl type maleimide compounds, etc. ,

[0050] Examples of derivatives of the compound having one or more N-substituted maleimide groups include aminomaleimide compounds containing a structural unit derived from the compound having one or more N-substituted maleimide groups and a structural unit derived from a diamine compound.

[0051] Examples of the structural unit derived from a compound having one or more N-substituted maleimide groups contained in the aminomaleimide compound include a structural unit obtained by Michael addition reaction of at least one N-substituted maleimide group among the N-substituted maleimide groups contained in the compound having one or more N-substituted maleimide groups and an amino group contained in a diamine compound.

[0052] The structural unit derived from a compound having one or more N-substituted maleimide groups contained in the aminomaleimide compound may be a single type or two or more types.

[0053] Examples of the structural unit derived from a diamine compound contained in the aminomaleimide compound include a structural unit obtained by Michael addition reaction of one or two of the two amino groups contained in the diamine compound and an N-substituted maleimide group contained in a compound having one or more N-substituted maleimide groups.

[0054] The structural unit derived from the diamine compound contained in the aminomaleimide compound may be a single type or two or more types.

[0055] Examples of the diamine compound include 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ketone, 4,4'-diaminobiphenyl, 3,3'-dimethyl 4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diaminodiphenylmethane, 2,2-bis(4-aminophenyl)propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis( 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 1,3-bis[1-[4-(4-aminophenoxy)phenyl]-1-methylethyl]benzene, 1,4-bis[1-[4-(4-aminophenoxy)phenyl]-1-methylethyl]benzene, 4,4'-[1,3-phenylenebis(1- Aromatic diamine compounds such as bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, and 9,9-bis(4-aminophenyl)fluorene; and organosilicon compounds having two primary amino groups. In the present disclosure, the term "aromatic diamine compound" refers to a compound having two amino groups directly bonded to an aromatic ring.

[0056] The maleimide compound can be used alone or in combination of two or more.

[0057] The compound having a vinylbenzyl group (hereinafter, sometimes referred to as a "vinylbenzyl compound") may have one or more vinylbenzyl groups, or may have two or more vinylbenzyl groups. Since the vinylbenzyl compound has one or more vinylbenzyl groups in one molecule, the reaction of the vinylbenzyl groups in the molecule or between molecules is promoted by heating or the like, thereby obtaining a cured product.

[0058] The vinylbenzyl compound can be used alone or in combination of two or more.

[0059] The vinylbenzyl compound may be any of a monomer, an oligomer, and a prepolymer, and a combination of two or more thereof may be contained in the resin composition.

[0060] When the vinylbenzyl compound is a monomer, it may be a compound in which one or more vinylbenzyl groups are introduced into the base compound. The oligomer may be a low-polymerization compound obtained by polymerizing two or more of the monomers. The prepolymer may be a prepolymer in which one or more vinylbenzyl groups are introduced into the resin skeleton, or may be a polymer of a monomer, oligomer or combination thereof having one or more vinylbenzyl groups. Both the oligomer and the prepolymer contain unreacted vinylbenzyl groups to some extent, and are preferably in a state where a curing reaction is initiated by heating or the like.

[0061] In the vinylbenzyl compound, in the case of a monomer, the number of the vinylbenzyl groups may be 1 or more or 2 or more, for example, 2 to 4 or 2 to 3.

[0062] In the case of the vinylbenzyl compound, in the case of an oligomer or a prepolymer, the number of vinylbenzyl groups in the molecule may be 1 or more, and preferably one or more vinylbenzyl groups are contained in the monomer structural unit. The number of vinylbenzyl groups in the monomer structural unit may be 2 to 4 or 2 to 3.

[0063] In the vinylbenzyl compound, the vinylbenzyl group may be any one of o-vinylbenzyl, m-vinylbenzyl and p-vinylbenzyl. When two or more vinylbenzyl groups are contained in one molecule of the vinylbenzyl compound, the two or more vinylbenzyl groups may be the same isomers or different isomers. From the viewpoint of dielectric properties, it is preferred that at least one p-vinylbenzyl group is contained in one molecule of the vinylbenzyl compound.

[0064] In one molecule of the vinylbenzyl compound, the p-vinylbenzyl group may be 10 to 100 mass %, 20 to 80 mass %, 30 to 70 mass %, or 40 to 60 mass % based on the total mass of all vinylbenzyl groups.

[0065] The vinylbenzyl compound may be, for example, a compound having one or more vinylbenzyl groups directly bonded to a carbon atom. The vinylbenzyl compound may be, for example, a compound containing an aromatic hydrocarbon structure. The vinylbenzyl compound may be, for example, a compound having one or more vinylbenzyl groups directly bonded to a carbon atom and containing an aromatic hydrocarbon structure.

[0066] The vinylbenzyl compound is preferably a hydrocarbon compound, for example, a hydrocarbon compound in which the structure other than the vinylbenzyl group is a non-aromatic hydrocarbon structure such as a chain hydrocarbon structure or an alicyclic hydrocarbon structure, or an aromatic hydrocarbon structure, but preferably a hydrocarbon compound in which the structure other than the vinylbenzyl group is an aromatic hydrocarbon structure.

[0067] The aromatic hydrocarbon structure may be a monocyclic or polycyclic aromatic ring, a condensed ring of two or more aromatic rings, or a condensed ring of an aromatic ring and a non-aromatic ring.

[0068] Examples of the aromatic hydrocarbon structure include an indene ring, an indane ring, a phenanthrene ring, an acenaphthene ring, and a fluorene ring. The indene ring, the indane ring, the phenanthrene ring, the acenaphthene ring, and the fluorene ring may be substituted or unsubstituted. In view of dielectric properties, an indene ring and a fluorene ring are preferred.

[0069] More preferably, the vinylbenzyl compound is a compound having an indene ring, and may be, for example, a hydrocarbon compound having an indene ring. In addition, it is preferred that the vinylbenzyl group is directly bonded to a carbon atom on the ring of the aromatic hydrocarbon structure.

[0070] Hereinafter, monomers in the vinylbenzyl compound will be described.

[0071] The vinylbenzyl compound as a monomer may be a compound containing an aromatic hydrocarbon structure. The vinylbenzyl compound as a monomer is preferably a hydrocarbon compound. For example, the vinylbenzyl compound as a monomer may be a hydrocarbon compound containing an aromatic hydrocarbon structure. As the aromatic hydrocarbon structure, for example, an indene ring, an indane ring, a phenanthrene ring, an acenaphthene ring, a fluorene ring, or a combination thereof is preferred, an indene ring, a fluorene ring, or a combination thereof is more preferred, and an indene ring is further preferred. For example, the vinylbenzyl compound may be a monomer having one or more vinylbenzyl groups and one indene ring in one molecule. For example, the vinylbenzyl compound as a monomer may be a hydrocarbon compound having one or more vinylbenzyl groups and one indene ring in one molecule.

[0072] An example of a vinylbenzyl compound is a monomer having an indene ring and having one or more vinylbenzyl groups bonded to any one of the 1-position, 2-position, and 3-position of the indene ring. The vinylbenzyl compound may be, for example, a compound having an indene ring, having one or more vinylbenzyl groups bonded to any one of the 1-position, 2-position, and 3-position of the indene ring, and further having a substituent other than the vinylbenzyl group directly bonded to a carbon atom of the indene ring. The vinylbenzyl compound may also be, for example, a compound having an indene ring, having one or more vinylbenzyl groups bonded to any one of the 1-position, 2-position, and 3-position of the indene ring, and having no substituent other than the vinylbenzyl group.

[0073] Specific examples of the vinylbenzyl compound include monomers represented by the following general formula (1).

[0074] [Chemistry 1]

[0075]

[0076] In general formula (1), n ​​is 1, 2 or 3, and n may also be 2 or 3. The mixture of monomers represented by general formula (1) may contain a plurality of monomers having different n. In this case, n is preferably 2 to 3, more preferably 2.0 to 2.5 on average.

[0077] In the general formula (1), the vinylbenzyl group may be directly bonded to any carbon atom at the 1-position, 2-position, and 3-position of the indene ring, preferably at the 1-position, or a combination of the 1-position and the 3-position. One or two vinylbenzyl groups may be bonded to each position. For example, the vinylbenzyl group is preferably bonded to a combination of the 1-position, the 1′-position, and the 3-position of the indene ring, or a combination of the 1-position and the 1′-position of the indene ring.

[0078] In the general formula (1), the methylene group of the vinylbenzyl group may be in any of the ortho, meta and para positions, preferably in the meta or para position. When the polymer is obtained using two or more monomers, it may be a mixture of an ortho-body, a meta-body and a para-body. In this case, a combination of a meta-body and a para-body is preferred, and the mass ratio of the meta-body to the para-body is preferably 40:60 to 60:40.

[0079] The following describes a method for synthesizing a monomer in a vinylbenzyl compound. It should be noted that the vinylbenzyl compound is a compound defined by its molecular structure regardless of the following synthesis method.

[0080] As a method for synthesizing the monomer in the vinylbenzyl compound, for example, a method of reacting a base compound having a desired structure such as indene or fluorene with a styrene having a halomethyl group in the presence of a basic compound can be cited. Examples of the styrene having a halomethyl group include o-chloromethylstyrene, m-chloromethylstyrene, p-chloromethylstyrene, and the like, and these may be one or a mixture of two or more. Examples of the basic compound include alkali metal hydroxides and alkali metal alkoxides.

[0081] A phase transfer catalyst may be used in the above reaction. Examples of the phase transfer catalyst include tetra-n-butylammonium bromide and the like. The reaction may be carried out by solution polymerization. The reaction may be carried out, for example, under heating and stirring. A polymerization inhibitor may also be added to the reaction system. The obtained product may be purified by known methods such as concentration, reprecipitation, and washing as required.

[0082] The obtained monomer may be a single compound or a monomer mixture of two or more compounds. For example, when indene is used as the base compound, a compound in which a vinylbenzyl group is directly bonded to at least one carbon atom in the 1st, 2nd and 3rd positions of the indene ring may be synthesized, and two or more isomers of vinylbenzyl compounds having different bonding sites may be included in the monomer mixture. In addition, depending on the synthesis conditions, a compound in which a vinylbenzyl group is directly bonded to at least two carbon atoms in the 1st, 2nd and 3rd positions of the indene ring may be obtained. In this case, two or more vinylbenzyl compounds having different bonding numbers and bonding sites of the vinylbenzyl group on the indene ring may also be included in the monomer mixture.

[0083] When the vinylbenzyl compound is a monomer, the molecular weight is not particularly limited, but is preferably 200 to 800, more preferably 250 to 750, and further preferably 300 to 700 from the viewpoint of moldability and handleability. When the vinylbenzyl compound is a monomer, the molecular weight is set to the weight average molecular weight (Mw) in the case of a mixture of a plurality of compounds.

[0084] Hereinafter, the prepolymer among the vinylbenzyl compounds will be described.

[0085] The vinylbenzyl compound as a prepolymer may be a compound containing an aromatic hydrocarbon structure. The vinylbenzyl compound as a prepolymer is preferably a hydrocarbon compound. For example, the vinylbenzyl compound as a prepolymer may be a hydrocarbon compound containing an aromatic hydrocarbon structure. As the aromatic hydrocarbon structure, for example, an indene ring, an indane ring, a phenanthrene ring, an acenaphthene ring, a fluorene ring, or a combination thereof is preferred, an indene ring, a fluorene ring, or a combination thereof is more preferred, and an indene ring is further preferred. For example, the vinylbenzyl compound may be a prepolymer containing a structural unit having one or more vinylbenzyl groups and one indene ring. For example, the vinylbenzyl compound as a prepolymer may be a hydrocarbon compound containing a structural unit having one or more vinylbenzyl groups and one indene ring.

[0086] The prepolymer can be obtained by polymerizing the monomer. It is preferred that the vinylbenzyl group is introduced from the monomer. For example, it is preferred to use a monomer having one or more vinylbenzyl groups, and preferably a monomer having more than two vinylbenzyl groups is used. The polymerization is not completely completed, but preferably stopped when the vinylbenzyl group derived from the monomer remains to a certain extent. For example, in order to obtain a curable prepolymer in a liquid state, it is preferred to stop the polymerization when the viscosity of the polymerization reaction system of the curable prepolymer reaches a certain level. In the polymerization of the prepolymer, an oligomer can be used together with the monomer, or an oligomer can be used instead of the monomer. For example, the polymerization of the prepolymer can use the monomer of the vinylbenzyl compound described above, or an oligomer of the monomer can be used.

[0087] When the vinylbenzyl compound is a prepolymer, the weight average molecular weight (Mw) may be, for example, 5,000 to 50,000 or 10,000 to 30,000 from the viewpoint of the fluidity of the resin composition.

[0088] Next, a method for polymerizing a vinyl benzyl compound to obtain a vinyl benzyl compound as a prepolymer is described. The polymerization of the vinyl benzyl compound is preferably carried out by free radical polymerization in a manner that no polar component is generated in the reaction product. The free radical polymerization can be carried out using a free radical polymerization initiator. The polymerization can be carried out by solution polymerization, and the polymerization solvent is not particularly limited. For example, one or a combination of two or more organic solvents used in the resin composition described later can be selected as the polymerization solvent.

[0089] The radical polymerization initiator may be a thermal radical polymerization initiator or a photoradical polymerization initiator, and a thermal radical polymerization initiator is preferred. The radical polymerization initiator is not particularly limited, and examples thereof include azo-based polymerization initiators and organic peroxide-based polymerization initiators.

[0090] Examples of the azo polymerization initiator include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylpropionitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylpropionic acid)dimethyl ester, 1,1'-azobis(methyl cyclohexylcarboxylate), 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), 4,4'-azobis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl-4-cyanopentanoate), and 1,1'-azobis(cyclohexane-1-carbonitrile).

[0091] Examples of the organic peroxide polymerization initiator include dicumyl peroxide, dibenzoyl peroxide, 2-butanone peroxide, t-butyl peroxybenzoate, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, bis(t-butylperoxyisopropyl)benzene, and t-butyl hydroperoxide.

[0092] In order to prevent polar components from being mixed into the resin composition, it is better to reduce the generation of polar by-products in the polymerization system. From this point of view, it is better to use a compound with a small amount of oxygen atoms in the free radical polymerization initiator. As such a compound, an azo polymerization initiator is preferred. Among them, among the azo polymerization initiators, it is preferred that the compound does not contain heteroatoms except the two nitrogen atoms (N) of the azo group. For example, the compound represented by the following general formula (2) can be listed.

[0093] R 1 -N=NR 2 (2)

[0094] In the general formula (2), R 1 and R 2are each independently a hydrogen atom or a monovalent functional group, R 1 and R 2 At least one of R is a monovalent functional group. 1 and R 2 They may be the same or different. The monovalent functional group is preferably a hydrocarbon group, which may be a saturated hydrocarbon group or an unsaturated hydrocarbon group, or an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The monovalent functional group is preferably a saturated or unsaturated aliphatic hydrocarbon group, and preferably an alkyl group.

[0095] The alkyl group may be any of a chain alkyl group and a cyclic alkyl group. The chain alkyl group may be a straight chain alkyl group or a branched chain alkyl group. The cyclic alkyl group may have a substituent bonded to a carbon atom on the ring.

[0096] The alkyl group may be, for example, an alkyl group having 1 to 10 carbon atoms, 3 to 8 carbon atoms, or 4 to 8 carbon atoms. Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, cyclohexyl, methylcyclohexyl, cyclohexylmethyl, heptyl, octyl, isooctyl, 2-ethylhexyl, nonyl, decyl, 1,1',3,3'-tetramethylbutyl, and 2,2',4,4'-tetramethylbutyl.

[0097] Specific examples of the compound represented by the general formula (2) include 2,2′-azobis(2,4,4-trimethylpentane) and 2,2′-azobis(2,4-dimethylvaleronitrile).

[0098] The radical polymerization initiator can be used alone or in combination of two or more.

[0099] The amount of the radical polymerization initiator used can be appropriately selected according to the desired degree of polymerization of the prepolymer. For example, the amount of the radical polymerization initiator used can be 0.05 to 5 parts by mass, 0.1 to 4 parts by mass, or 0.5 to 2 parts by mass relative to 100 parts by mass of the vinylbenzyl compound in the polymerization system.

[0100] The vinylbenzyl compound as a prepolymer may be a homopolymer of the vinylbenzyl compound, or a copolymer. The copolymer may be a copolymer of two or more vinylbenzyl compounds, or a copolymer of the vinylbenzyl compound and other monomers. In the case of a copolymer, it may be a random copolymer, a block copolymer, etc.

[0101] The vinylbenzyl compound may be an oligomer of the above-mentioned monomer having a low degree of polymerization.

[0102] From the viewpoint of moldability, the amount of the solid content of the component (A) relative to the resin composition may be 10% by mass or more, 20% by mass or more, or 30% by mass or more. On the other hand, from the viewpoint of flame retardancy, the amount of the solid content of the component (A) relative to the resin composition may be 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, or 30% by mass or less. For example, the amount of the solid content of the component (A) relative to the resin composition may be 10 to 70% by mass, 10 to 60% by mass, 20 to 50% by mass, 30 to 40% by mass, 10 to 20% by mass, 20 to 30% by mass, or 30 to 40% by mass.

[0103] In the present disclosure, the "solid content" of a resin composition refers to the components in the resin composition other than volatile substances such as water and solvents described later. The solid content is a component that does not volatilize and remains when the resin composition is dried, and also includes components that are liquid, syrupy, or waxy at room temperature around 25°C, and does not necessarily mean solid.

[0104] From the viewpoint of moldability, the amount of component (A) may be 50% by mass or more, 60% by mass or more, or 70% by mass or more, relative to the total amount of component (A) and component (B) described later ((B) an acenaphthene polymer having a number average molecular weight of 1,000 or more). On the other hand, from the viewpoint of flame retardancy, the amount of component (A) may be 99% by mass or less, 95% by mass or less, or 90% by mass or less, relative to the total amount of component (A) and component (B). For example, the amount of component (A) may be 50 to 99% by mass, 60 to 95% by mass, or 70 to 90% by mass relative to the total amount of component (A) and component (B).

[0105] <(B) Acenaphthene polymer having a number average molecular weight of 1,000 or more>

[0106] (B) The acenaphthene polymer may have a structural unit derived from acenaphthene. The structural unit derived from acenaphthene may be substituted or unsubstituted.

[0107] (B) The acenaphthene polymer preferably has a structural unit containing an acenaphthene structure represented by the following formula (3). In the following formula (3), * is a bonding portion to other structural units. In the following formula (3), the acenaphthene structure may have no substituent or may have one or more substituents. As the substituent, for example, an alkyl group can be mentioned, and as the alkyl group, for example, it can be any of a chain alkyl group and a cyclic alkyl group. For example, the alkyl group can be an alkyl group having 1 to 10 carbon atoms or 1 to 4 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, a butyl group, etc. can be mentioned.

[0108] [Chemistry 2]

[0109]

[0110] (B) The acenaphthene polymer may be a homopolymer of acenaphthene or a copolymer. The copolymer may be a copolymer of two or more monomers selected from the group consisting of substituted or unsubstituted acenaphthene, or a copolymer of acenaphthene and other monomers. In the case of a copolymer, it may be a random copolymer, a block copolymer, or the like.

[0111] The acenaphthene polymer (B) may contain, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 95% by mass or more of a structural unit derived from acenaphthene. The acenaphthene polymer (B) may contain, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 95% by mass or more of a structural unit represented by formula (3).

[0112] The (B) acenaphthene polymer is preferably a homopolymer of acenaphthene. For example, the (B) acenaphthene polymer may be a homopolymer of unsubstituted acenaphthene.

[0113] The number average molecular weight (Mn) of the acenaphthene polymer (B) is preferably 1,000 or more from the viewpoint of easily obtaining low sublimation properties.

[0114] The number average molecular weight (Mn) of the acenaphthene polymer (B) is more preferably 2,000 or more, further preferably 5,000 or more, and further preferably 20,000 or more. The number average molecular weight (Mn) of the acenaphthene polymer (B) may be 100,000 or less or 50,000 or less. The number average molecular weight (Mn) of the acenaphthene polymer (B) may be, for example, 1,000 to 100,000, 2,000 to 100,000, 5,000 to 50,0000, or 2,000 to 50,000.

[0115] The weight average molecular weight (Mw) of the acenaphthene polymer (B) is preferably 2,000 or more, more preferably 5,000 or more, and further preferably 10,000 or more. The weight average molecular weight (Mw) of the acenaphthene polymer (B) may be 1,000,000 or less or 500,000 or less. The weight average molecular weight (Mw) of the acenaphthene polymer (B) may be, for example, 2,000 to 1,000,000, 5,000 to 1,000,000, or 10,000 to 500,000.

[0116] (B) The acenaphthene polymer can be obtained, for example, by polymerizing acenaphthene with other monomers as required. The polymerization can be carried out, for example, by free radical polymerization. The free radical polymerization can be carried out using a free radical polymerization initiator. The polymerization can be carried out by solution polymerization, and the polymerization solvent is not particularly limited. For example, one or a combination of two or more organic solvents used in the resin composition described later can be selected and used as the polymerization solvent.

[0117] The radical polymerization initiator is not particularly limited, and examples thereof include azo polymerization initiators, organic peroxide polymerization initiators, etc. Specifically, it can be appropriately selected from the azo polymerization initiators and organic peroxide polymerization initiators exemplified in the description of the method for obtaining the vinylbenzyl compound as a prepolymer.

[0118] For example, in the case of using free radical polymerization, a polymerization solution obtained by adding a free radical polymerization initiator and a polymerization solvent to an acenaphthene monomer and other monomers as needed can be heated under a nitrogen atmosphere to obtain (B) an acenaphthene polymer. The amount of the free radical polymerization initiator can be, for example, 0.1 to 10 parts by mass relative to 100 parts by mass of the monomer, for example, about 5 parts by mass. The amount of the polymerization solvent can be an amount that makes the total amount of the monomer and the polymerization initiator in the polymerization solution 5 to 80% by mass, for example, an amount that makes the total amount of the monomer and the polymerization initiator in the polymerization solution about 30% by mass. The heating temperature can be, for example, 50 to 150° C., for example, about 110° C. In addition, the heating time can be 1 to 50 hours, for example, about 15 hours.

[0119] (B) The acenaphthene polymer may be used alone or in combination of two or more.

[0120] From the viewpoint of flame retardancy, the amount of component (B) relative to the solid content of the resin composition may be greater than or equal to 0.1 mass %, greater than or equal to 1 mass %, or greater than or equal to 5 mass %. On the other hand, the amount of component (B) relative to the solid content of the resin composition may be less than or equal to 40 mass %, less than or equal to 30 mass %, less than or equal to 20 mass %, or less than or equal to 10 mass %. For example, the amount of component (B) relative to the solid content of the resin composition may be 0.1 to 40 mass %, 1 to 30 mass %, 1 to 20 or 5 to 10 mass %.

[0121] From the viewpoint of flame retardancy, the amount of the component (B) relative to the total amount of the components (A) and (B) may be 1% by mass or more, 5% by mass or more, or 10% by mass or more.

[0122] On the other hand, from the viewpoint of moldability, the amount of component (B) relative to the total amount of components (A) and (B) may be 50% by mass or less, 40% by mass or less, or 30% by mass or less. The amount of component (B) relative to the total amount of components (A) and (B) may be, for example, 1 to 50% by mass, 5 to 40% by mass, or 10 to 30% by mass.

[0123] <Other ingredients>

[0124] The resin composition may contain other components besides the above-mentioned components as necessary.

[0125] Examples of other components include flame retardants, inorganic fillers, solvents, polymerization initiators, elastomers, resins other than the above components, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, pigments, colorants, lubricants, and the like.

[0126] The resin composition may contain a flame retardant. The flame retardant is not particularly limited, and for example, a phosphorus-based flame retardant may be used.

[0127] Phosphorus-based flame retardants include, for example, aromatic phosphate compounds such as triphenyl phosphate, tricresyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, cresyl di-2,6-xylyl phosphate, resorcinol bis(diphenyl phosphate), 1,3-phenylene bis(di-2,6-xylyl phosphate), bisphenol A-bis(diphenyl phosphate), and 1,3-phenylene bis(diphenyl phosphate); phosphonates such as divinyl phenylphosphonate, diallyl phenylphosphonate, and bis(1-butenyl) phenylphosphonate; and diphenylphosphine. Phosphinates such as phosphinate esters such as phenyl diphenylphosphinate and methyl diphenylphosphinate; phosphazene compounds such as bis(2-allylphenoxy)phosphazene and xylenephosphazene; 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide as its derivative; melamine phosphate, melamine pyrophosphate, melamine polyphosphate, polyphosphate melam, ammonium polyphosphate, phosphorus-containing vinylbenzyl compounds, metal salts of phosphinate compounds, red phosphorus, etc.

[0128] The flame retardants may be used alone or in combination of two or more.

[0129] The amount of the flame retardant relative to the solid content of the resin composition may be, for example, 0.1 to 30 mass %, 1 to 20 mass %, 1 to 10 mass %, 10 to 20 mass %, or 20 to 30 mass %.

[0130] The resin composition may contain an inorganic filler. Examples of the inorganic filler include silicon dioxide (SiO2), aluminum oxide (Al2O3), titanium oxide, barium titanate, strontium titanate, potassium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, aluminum borate, silicon carbide, mica, beryllium oxide, clay, talc, etc. From the viewpoint of dielectric properties, silicon dioxide is preferred.

[0131] The shape and size of the inorganic filler are not particularly limited. The average particle size of the inorganic filler can be, for example, 0.01 to 20 μm or 0.1 to 10 μm. Here, the average particle size of the inorganic filler is the particle size corresponding to the point of 50% of the cumulative value in the volume-based particle distribution based on the laser diffraction scattering method.

[0132] The inorganic filler can be used alone or in combination of two or more.

[0133] The amount of the inorganic filler relative to the solid content of the resin composition may be, for example, 10 to 80% by volume, 20 to 70% by volume, or 30 to 60% by volume.

[0134] The amount of the inorganic filler relative to the solid content of the resin composition may be, for example, 30 to 90% by mass, 40 to 90% by mass, or 50 to 80% by mass.

[0135] The resin composition may further contain a polymerization initiator in order to promote curing of the (A) thermosetting resin.

[0136] As the polymerization initiator, a free radical polymerization initiator can be used. As the free radical polymerization initiator, it can be a thermal free radical polymerization initiator, it can also be a photo free radical polymerization initiator, preferably a thermal free radical polymerization initiator. The free radical polymerization initiator is not particularly limited, and azo polymerization initiators, organic peroxide polymerization initiators, etc. can be cited. Specifically, it can be appropriately selected from the azo polymerization initiators, organic peroxide polymerization initiators, etc. exemplified in the description of the method for obtaining the vinyl benzyl compound as a prepolymer.

[0137] The polymerization initiator can be used alone or in combination of two or more.

[0138] The amount of the polymerization initiator used may be appropriately adjusted, and may be, for example, 0.01 to 5 parts by mass, 0.1 to 4 parts by mass, or 0.5 to 2 parts by mass relative to 100 parts by mass of the thermosetting resin (A).

[0139] Examples of the elastomer include styrene elastomers, olefin elastomers, polyurethane elastomers, polyester elastomers, polyamide elastomers, acrylic elastomers, and silicone elastomers. The elastomer may be used alone or in combination of two or more.

[0140] The resin composition may be a solvent-free resin composition or may contain a solvent. For example, the resin composition contains a liquid compound as a thermosetting resin, may be a solvent-free resin composition, or may contain a thermosetting resin and a solvent. The solvent can adjust the viscosity of the resin composition and further improve the coating property. As the solvent, an organic solvent is preferred.

[0141] Examples of the organic solvent include alcohol solvents such as ethanol, propanol, butanol, methyl cellosolve, ethylene glycol monobutyl ether, and propylene glycol monomethyl ether; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether solvents such as tetrahydrofuran; aromatic hydrocarbon solvents such as toluene, xylene, and mesitylene; nitrogen atom-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; sulfur atom-containing solvents such as dimethyl sulfoxide; ester solvents such as γ-butyrolactone, etc. The organic solvent may be used alone or in combination of two or more.

[0142] When the resin composition contains a solvent, the solid content of the resin composition may be, for example, 10 to 90% by mass, 30 to 80% by mass, or 40 to 75% by mass relative to the total mass of the resin composition.

[0143] <Method for producing resin composition>

[0144] The method for producing the resin composition is not particularly limited. The resin composition of one embodiment is not limited by the method for producing, and its characteristics are as described in the present disclosure. As an example of a method for producing a resin composition, any component can be added to (A) a thermosetting resin and (B) an acenaphthene polymer as needed and mixed to obtain a resin composition. In more detail, for example, (A) a thermosetting resin and (B) an acenaphthene polymer can be dissolved or dispersed in a solvent, and a flame retardant, an inorganic filler, etc. can be added and mixed as needed to obtain a resin composition. The mixing order, temperature, time and other conditions of each component are not particularly limited, and can be appropriately adjusted according to the type of raw materials, the scale of production, the production equipment, etc.

[0145] <Dielectric properties of cured product>

[0146] The relative dielectric constant (Dk) of the cured product of the resin composition at 25°C and 10 GHz is preferably less than or equal to 4.0, more preferably less than or equal to 3.5, and further preferably less than or equal to 3.4. The smaller the relative dielectric constant (Dk) of the cured product of the resin composition at 25°C and 10 GHz, the more preferred it is, and its lower limit is not particularly limited. Considering the balance with other physical properties, it may be, for example, greater than or equal to 2.3 or greater than or equal to 2.4. For example, the relative dielectric constant (Dk) of the cured product of the resin composition at 25°C and 10 GHz may be 2.3 to 4.0, preferably 2.3 to 3.5 or 2.4 to 3.4.

[0147] The dielectric loss tangent (Df) of the cured product of the resin composition at 25°C and 10 GHz is preferably less than or equal to 0.0020, more preferably less than or equal to 0.0015, and further preferably less than or equal to 0.0013. The smaller the dielectric loss tangent (Df) of the cured product of the resin composition at 25°C and 10 GHz, the more preferred it is. The lower limit is not particularly limited, and in consideration of the balance with other physical properties, for example, it may be greater than or equal to 0.0001 or greater than or equal to 0.00050.

[0148] For example, the dielectric loss tangent (Df) of the cured product of the resin composition at 25° C. and 10 GHz may be 0.0001 to 0.0020, preferably 0.00050 to 0.0015 or 0.00050 to 0.0013.

[0149] In the present disclosure, relative dielectric constant (Dk) and dielectric loss tangent (Df) at 25° C. and 10 GHz are measured by SPDR method (split-pin dielectric resonator) at 10 GHz band and 25° C. The measuring device can be "PNA Network Analyzer N5227A" (trade name) from Agilent Technologies.

[0150] The sample to be measured for the relative dielectric constant (Dk) and dielectric loss tangent (Df) of the cured product of the resin composition is a sample obtained by curing the resin composition to a C-stage state in JIS K 6800 (1985).

[0151] [Prepreg]

[0152] According to one embodiment, a prepreg formed using a resin composition can be provided. The prepreg can be formed, for example, using a resin composition and a fiber substrate. As the resin composition, the above-mentioned resin composition can be used. The details of the resin composition are as shown in the above description.

[0153] The prepreg may include the above-mentioned resin composition or a semi-cured product of the above-mentioned resin composition.

[0154] In the present disclosure, as one index of the semi-cured product, the B-stage state in JIS K 6800 (1985) can be cited.

[0155] The prepreg may contain, for example, a resin composition or a semi-cured product of the resin composition and a fiber substrate such as a sheet-like fiber substrate. In the prepreg, the resin composition may be in an uncured state, or the resin composition may be partially or entirely in a semi-cured state. For example, the prepreg is used to assemble a molded product such as a laminate, and cured by heat treatment or the like, thereby obtaining a cured product.

[0156] Prepregs can be obtained, for example, by coating a resin composition on a fiber substrate and drying it. For example, prepregs can be obtained by impregnating a fiber substrate in a resin composition, coating it, and drying the fiber substrate impregnated with the resin composition. Drying is preferably carried out at a temperature greater than or equal to a temperature at which volatile components such as solvents that may be contained in the resin composition can be removed, and can also be carried out at a temperature greater than or equal to a temperature at which the thermosetting resin contained in the resin composition is semi-cured, depending on the application. In addition, it is preferred that the drying is adjusted in such a way that the thermosetting resin contained in the resin composition is not completely cured. From this point of view, the drying temperature can be, for example, 80 to 200°C, and the drying time can be, for example, 1 to 30 minutes, depending on the drying temperature and the drying device, its scale, etc. (B) Acenaphthene polymers have low sublimation properties, and when the above-mentioned resin composition containing (B) Acenaphthene polymers is used, there is a tendency that furnace contamination is not easy to occur.

[0157] The fiber substrate may be any of woven fabric, knitted fabric and nonwoven fabric. The fiber substrate may be provided in the form of chopped strand mat, roving and the like.

[0158] The fiber material may be either inorganic fiber or organic fiber.

[0159] As inorganic fibers, glass fibers, carbon fibers, etc. can be cited. As glass fibers, E glass, NE glass, D glass, S glass, Q glass, etc. can be cited. As organic fibers, polyimide, polyester, tetrafluoroethylene, etc. can be cited. The fiber substrate can use one of these fibers alone, or two or more of them can be used in combination.

[0160] From the viewpoint of dielectric properties and heat resistance, the material of the fiber base material is preferably inorganic fiber, more preferably glass fiber.

[0161] The fiber base material may be appropriately selected depending on the application of the prepreg, and a sheet-like fiber base material is preferred.

[0162] As the sheet-like fiber base material, for example, various sheet-like fiber base materials used in known laminated plates for electrical insulating materials may be used.

[0163] The thickness of the sheet-like fiber substrate is not particularly limited, but is preferably 0.02 to 0.5 mm, for example. The thickness is measured at five points at equal distances across the entire surface of the sheet-like fiber substrate, and the thickness is taken as the arithmetic mean of the five points.

[0164] [Resin film]

[0165] According to one embodiment, a resin film formed using a resin composition can be provided. The resin film can be produced using the resin composition. The details of the resin composition are as described above.

[0166] The resin film may include the above-mentioned resin composition or a semi-cured product of the above-mentioned resin composition. In the resin film, the resin composition may be in an uncured state, and the resin composition may also be partially or entirely in a semi-cured state. For example, by curing the resin film using a heat treatment, a cured product can be obtained.

[0167] The resin film can be obtained, for example, by applying a resin composition on a coated material and drying it. Drying can be performed in the same manner as in the above-mentioned method for manufacturing prepregs. The resin film can also be dried on the coated material to provide a product in the form of a combination of the resin film and the coated material. For example, in this method, a resin film can be provided in order to form an insulating layer on a coated material in an electronic device, etc. In other methods, the resin film can also be dried on the coated material, and then the resin film can be peeled off from the coated material and the resin film can be provided as a product.

[0168] As the coated material, it can be any one of an inorganic substrate and an organic substrate, it can be a glass substrate, a metal foil, a metal plate and other metal substrates, a plastic substrate such as a plastic plate, a plastic film, a paper substrate, etc. It can also be the fiber substrate described in the above-mentioned prepreg. In order to provide the resin film peeled off from the coated material, a coated material having a release layer formed on the surface can be used.

[0169] [Metal-clad laminate]

[0170] According to one embodiment, a metal-clad laminate including a cured product of a resin composition and a metal foil can be provided. The metal-clad laminate can be, for example, a metal-clad laminate including a cured product of a prepreg and a metal foil.

[0171] According to another embodiment, a metal-clad laminate formed using a prepreg and a metal foil may be provided. The metal-clad laminate may be, for example, a metal-clad laminate including a cured product of a prepreg and a metal foil.

[0172] The details of the resin composition and the prepreg are as described above.

[0173] The metal-clad laminate preferably comprises a resin cured material layer containing a resin cured material and a metal foil disposed on at least one side of the resin cured material layer. The resin cured material layer comprises a cured material of the above-mentioned resin composition, and may also be a cured material of the above-mentioned prepreg. For example, in the metal-clad laminate, a metal foil is disposed on at least one side of the cured material of the prepreg, and more preferably a metal foil is disposed on both sides of the cured material of the prepreg. The metal-clad laminate may be a laminate manufactured by disposing a metal foil on at least one side of a sheet-like prepreg, or may be a laminate manufactured by stacking more than two sheet-like prepregs and disposing a metal foil on at least one side of the outermost surface of the laminate. For example, the metal-clad laminate may be a laminate manufactured by stacking more than two sheet-like prepregs and disposing a metal foil on both sides of the laminate.

[0174] Hereinafter, as a specific example of a method for producing a metal-clad laminate, a method of disposing a metal foil on a laminate of two or more sheet-like prepregs will be described. Figure 1 , a schematic cross-sectional view of a metal-clad laminate 10 including a plurality of cured products 2 of prepregs and a metal foil 1 is shown as a specific example of the metal-clad laminate.

[0175] First, two or more sheet-like prepregs are stacked to obtain a laminate. In the laminate, the two or more sheet-like prepregs may be identical to each other, or may be partially or completely different. In the laminate, at least one of the two or more sheet-like prepregs may be a material obtained using the resin composition of one embodiment.

[0176] Next, a metal foil is placed on at least one surface of the laminate.

[0177] The laminated body provided with the metal foil is heated and pressurized. Thus, a curing reaction of the sheet-like prepreg is carried out, and a cured product of the prepreg can be obtained. In addition, the sheet-like prepregs adjacent to each other can be fixed. The heating and pressurizing conditions are not particularly limited, and for example, the temperature can be 100 to 300° C., the time can be 10 to 300 minutes, and the pressure can be 1.5 to 5 MPa. In addition, after heating and pressurizing, in order to further cure the prepreg, reheating can be performed. The reheating temperature in this case can be 100 to 300° C.

[0178] As a 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.

[0179] The acenaphthene polymer (B) has low sublimation properties, and when the resin composition containing the acenaphthene polymer (B) is used, there is a tendency that furnace contamination is less likely to occur.

[0180] The metal of the metal foil is not particularly limited, and examples thereof include copper, nickel, aluminum, gold, silver, platinum, molybdenum, ruthenium, tungsten, iron, titanium, chromium, and alloys containing two or more of these metal elements. Industrially, single metals of copper, nickel, and aluminum are preferred. By using copper as the metal foil, a copper-clad laminate can be provided.

[0181] The dielectric properties of the assembled metal-clad laminate in a state where the metal foil is removed are preferably as follows: The metal-clad laminate in a state where the metal foil is removed is also simply referred to as a metal foil removed product.

[0182] The relative dielectric constant (Dk) of the metal foil removed product at 25°C and 10 GHz is preferably 4.0 or less, more preferably 3.5 or less, and further preferably 3.4 or less. The smaller the relative dielectric constant (Dk) of the metal foil removed product at 25°C and 10 GHz, the better. The lower limit is not particularly limited, but in consideration of the balance with other physical properties, it may be, for example, 2.3 or more or 2.4 or more.

[0183] For example, the relative dielectric constant (Dk) of the metal foil removed product at 25° C. and 10 GHz may be 2.3 to 4.0, preferably 2.3 to 3.5 or 2.4 to 3.4.

[0184] The dielectric loss tangent (Df) of the metal foil removed product at 25°C and 10 GHz is preferably 0.0020 or less, more preferably 0.0015 or less, and further preferably 0.0013 or less. The smaller the dielectric loss tangent (Df) of the metal foil removed product at 25°C and 10 GHz, the better. The lower limit is not particularly limited, but in consideration of the balance with other physical properties, it may be, for example, 0.0001 or more or 0.00050 or more.

[0185] For example, the dielectric loss tangent (Df) of the metal foil removed product at 25° C. and 10 GHz may be 0.0001 to 0.0020, preferably 0.00050 to 0.0015 or 0.00050 to 0.0013.

[0186] The relative dielectric constant (Dk) and dielectric loss tangent (Df) of the material from which the metal foil is removed may be measured in the same manner as the relative dielectric constant (Dk) and dielectric loss tangent (Df) of the cured material of the resin composition.

[0187] The samples for the measurement of the relative dielectric constant (Dk) and dielectric loss tangent (Df) of the metal foil removed product were prepared by immersing the metal-clad laminate in an etching solution to remove the metal foil, and cutting out 60 mm and 100 mm evaluation substrates from the test piece from which the metal foil was removed. In the case of the copper-clad laminate, a 10 mass % ammonium persulfate solution was used as the etching solution.

[0188] [Printed wiring board]

[0189] According to one embodiment, a printed wiring board including a cured product of a resin composition can be provided. The details of the resin composition are as described above.

[0190] In the printed wiring board, the cured product of the resin composition can be manufactured using a resin composition, a prepreg, a resin film, a metal-clad laminate or a combination thereof. For example, a printed wiring board can be provided by forming wiring to the cured product of the prepreg using a known method. In other examples, a printed wiring board can be provided by using a metal-clad laminate and forming wiring using a known method. It can also be a printed wiring board combining these examples. The details of the prepreg, the resin film and the metal-clad laminate are as shown in the above description.

[0191] The printed wiring board may be either a single-layer printed wiring board or a multi-layer printed wiring board.

[0192] [Semiconductor package]

[0193] According to one embodiment, a semiconductor package including a printed wiring board and a semiconductor element can be provided. In more detail, a semiconductor package including a printed wiring board and a semiconductor element containing a cured product of a resin composition can be provided. The details of the resin composition are as shown in the above description. The details of the cured product of the resin composition and the printed wiring board are also as shown in the above description. The semiconductor package can be manufactured, for example, by mounting semiconductor elements, memory, etc. on a printed wiring board using a known method. As an insulating material, a sealing material, etc. of a semiconductor package, a cured product of a resin composition can also be used.

[0194] [Acenaphthene homopolymer having a number average molecular weight of 1,000 or more]

[0195] According to one embodiment, an acenaphthene homopolymer having a number average molecular weight of 1,000 or more (hereinafter sometimes referred to as "acenaphthene homopolymer") may be provided. The acenaphthene homopolymer may have a structural unit derived from acenaphthene. The structural unit derived from acenaphthene may be substituted or unsubstituted.

[0196] The acenaphthene homopolymer is a homopolymer of acenaphthene, and more specifically, a homopolymer of substituted or unsubstituted acenaphthene. The acenaphthene homopolymer may be, for example, a homopolymer of unsubstituted acenaphthene.

[0197] The acenaphthene homopolymer may have a structure having a structural unit including an acenaphthene structure represented by the following formula (4): In the formula (4), n is an integer in the range of a number average molecular weight of 1,000 or more.

[0198] [Chemistry 3]

[0199]

[0200] In the following formula (4), the acenaphthene structure may have no substituent or may have one or more substituents. Examples of the substituent include alkyl groups, and examples of the alkyl group include any of chain alkyl groups and cyclic alkyl groups. Examples of the alkyl group include alkyl groups having 1 to 10 carbon atoms or 1 to 4 carbon atoms, and examples thereof include methyl groups, ethyl groups, propyl groups, and butyl groups.

[0201] The number average molecular weight (Mn) of the acenaphthene homopolymer is preferably 1,000 or more from the viewpoint of easily obtaining low sublimation properties.

[0202] The number average molecular weight (Mn) of the acenaphthene homopolymer is more preferably greater than or equal to 2,000, and further preferably greater than or equal to 5,000. The number average molecular weight (Mn) of the acenaphthene homopolymer may be less than or equal to 100,000 or less than or equal to 50,000. The number average molecular weight (Mn) of the acenaphthene homopolymer may be, for example, 1,000 to 100,000, 2,000 to 100,000, or 5,000 to 50,0000.

[0203] The weight average molecular weight (Mw) of the acenaphthene homopolymer is preferably greater than or equal to 2,000, more preferably greater than or equal to 5,000, and further preferably greater than or equal to 10,000. The weight average molecular weight (Mw) of the acenaphthene homopolymer may be less than or equal to 1,000,000 or less than or equal to 500,000. The weight average molecular weight (Mw) of the acenaphthene homopolymer may be, for example, 2,000 to 1,000,000, 5,000 to 1,000,000, or 10,000 to 500,000.

[0204] Examples of the method for producing an acenaphthene homopolymer include a method of homopolymerizing acenaphthene using acenaphthene as a monomer in the method described as the method for producing the acenaphthene polymer (B).

[0205] Preferred examples of the embodiments of the present disclosure are listed below. The embodiments of the present invention are not limited to the following examples.

[0206] <1>

[0207] A resin composition comprising (A) a thermosetting resin and (B) an acenaphthene polymer having a number average molecular weight of 1,000 or more.

[0208] <2>

[0209] according to <1> The resin composition comprises 5% by mass or more of the acenaphthene polymer (B) having a number average molecular weight of 1,000 or more relative to the total amount of the (A) thermosetting resin and the (B) acenaphthene polymer having a number average molecular weight of 1,000 or more.

[0210] <3>

[0211] according to <1> or <2> In the resin composition, the (A) thermosetting resin contains a compound having a vinyl benzyl group.

[0212] <4>

[0213] A prepreg, using <1> ~ <3> The resin composition described in any one of the above is formed.

[0214] <5>

[0215] A resin film, using <1> ~ <3> The resin composition described in any one of the above is formed.

[0216] <6>

[0217] A metal-clad laminate comprising <1> ~ <3> A cured product of the resin composition described above, and a metal foil.

[0218] <7>

[0219] A metal-clad laminate, using <4> The prepreg and metal foil are formed.

[0220] <8>

[0221] A printed wiring board comprising <1> ~ <3> A cured product of any one of the resin compositions.

[0222] <9>

[0223] A semiconductor package comprising <8> The printed wiring board and the semiconductor element.

[0224] <10>

[0225] An acenaphthene homopolymer having a number average molecular weight greater than or equal to 1,000.

[0226] The disclosure of the present application is related to the subject matter described in Japanese Patent Application No. 2023-063536 filed on April 10, 2023, and all the disclosed contents are incorporated herein by reference.

[0227] Example

[0228] Hereinafter, the present embodiment will be described in more detail with reference to Examples, but the present embodiment is not limited to the following Examples.

[0229] "Manufacture of vinylbenzyl compounds"

[0230] In a 500 mL reaction container equipped with a stirring device, a thermometer, a reflux tube and a nitrogen inlet, 35.6 parts by mass of indene, 101.2 parts by mass of chloromethylstyrene described below, 7.1 parts by mass of tetra-n-butylammonium bromide (manufactured by Kanto Chemical Co., Ltd.) as a phase transfer catalyst, 0.1 parts by mass of phenothiazine as a polymerization inhibitor, and 77.6 parts by mass of toluene as a solvent were placed, and the mixture was heated and stirred at 40° C. while nitrogen gas was blown in at a flow rate of 50 ml / min.

[0231] Chloromethylstyrene "CMS-P": AGC Seimi Chemical Co., Ltd., a mixture of meta-form and para-form, with the meta-form content being 50% by mass and the para-form content being 50% by mass.

[0232] Next, 46.5 parts by mass of an aqueous solution of the following basic compound was added dropwise over 20 minutes, and the mixture was stirred at 60° C. for 9 hours. It should be noted that nitrogen was continuously blown in during the reaction. The mixture was cooled to room temperature (25° C.), neutralized with a 10% aqueous hydrochloric acid solution, washed twice with pure water, toluene was distilled off under reduced pressure, and the obtained viscous liquid was washed with methanol and then vacuum dried to obtain a vinyl benzyl compound.

[0233] Aqueous solution of alkaline compound: 48% by mass sodium hydroxide aqueous solution, Kanto Chemical Co., Ltd.

[0234] The obtained vinylbenzyl compound is prepared by 1 H-NMR analysis confirmed that it has a structure of a vinylbenzyl group directly bonded to the carbon atom at position 1, position 3 or a combination thereof of the indene represented by the following formula (5). In addition, by GPC analysis, the vinylbenzyl compound is a mixture of a compound having two vinylbenzyl groups introduced and a compound having three vinylbenzyl groups introduced. In the case where three vinylbenzyl groups are introduced into the vinylbenzyl compound, it is confirmed that there are two vinylbenzyl groups directly bonded to the carbon atom at position 1 of the indene ring and one vinylbenzyl group directly bonded to the carbon atom at position 3. The weight average molecular weight (Mw) of the vinylbenzyl compound is 500. The weight average molecular weight is measured by the following method.

[0235] [Chemistry 4]

[0236]

[0237] "Method for determining weight average molecular weight (Mw)"

[0238] The weight average molecular weight is calculated by gel permeation chromatography (GPC) from a calibration curve using standard polystyrene. The calibration curve is approximated by a cubic equation using standard polystyrene: TSKstandard POLYSTYRENE (Type: A-2500, A-5000, F-20, F-80) (manufactured by Tosoh Corporation, trade name). The measurement conditions of GPC are as follows.

[0239] Device: High-speed GPC device HLC-8320GPC (Tosoh Corporation, trade name)

[0240] Detector: UV-8320 ultraviolet absorption detector (Tosoh Corporation, trade name)

[0241] Column: Guard column: TSKgel guardcolumn Super(HZ)-M+, column: TSKgel SuperMultiporeHZ-M (2 pieces), reference column: TSKgel SuperH-RC (2 pieces) (all trade names of Tosoh Corporation)

[0242] Column size: 4.6×20mm (guard column), 4.6×150mm (column), 6.0×150mm (reference column)

[0243] Eluent: Tetrahydrofuran

[0244] Sample concentration: 10mg / 1mL

[0245] Injection volume: 20μL or 2μL

[0246] Flow rate: 0.35mL / min

[0247] Measurement temperature: 40℃

[0248] [Production of Acenaphthene Polymers Y1 and Y2]

[0249] To 100 parts by mass of the solid content of the unsubstituted acenaphthene monomer, 5 parts by mass of an azo polymerization initiator (2,2'-azobis(2,4,4-trimethylpentane)) was added, and the solution diluted with toluene to a solid content of 30% by mass was heated at 110° C. for 15 hours in a nitrogen atmosphere to prepare an acenaphthene polymer Y1 which is a homopolymer of acenaphthene.

[0250] The number average molecular weight (Mn) of the obtained acenaphthene polymer Y1 was 5,300 and the weight average molecular weight (Mw) was 18,000.

[0251] The obtained resin was subjected to NMR measurement, and as a result, the peak at around 7.1 ppm derived from the acenaphthene monomer disappeared.

[0252] In addition, in the method for producing the acenaphthene polymer Y1, the amount of the azo polymerization initiator added was changed to 1 part by mass relative to 100 parts by mass of the solid content of the unsubstituted acenaphthene monomer, and the acenaphthene polymer Y2 was produced by the same method as the method for producing the acenaphthene polymer Y1. The number average molecular weight (Mn) of the obtained acenaphthene polymer Y2 was 28,000, and the weight average molecular weight (Mw) was 140,000.

[0253] The number average molecular weight (Mn) and the weight average molecular weight (Mw) are calculated by gel permeation chromatography (GPC) from a calibration curve using standard polystyrene. The calibration curve is approximated by a cubic equation using standard polystyrene: TSKstandard POLYSTYRENE (Type: A-2500, A-5000, F-20, F-80) (manufactured by Tosoh Corporation, trade name). The measurement conditions of GPC are as described above.

[0254] [Manufacturing of resin composition]

[0255] The components listed in Table 1 were stirred and mixed with toluene at 25°C according to the amounts listed in Table 1 to prepare resin compositions (varnishes) of Examples 1 to 3 and Comparative Examples 1 to 2 having a solid content concentration of about 75% by mass. In Table 1, the unit of the amount of each component is parts by mass, and when the component is a solution, it refers to the parts by mass converted to solid content. Regarding the inorganic filler, the value in vol% relative to the solid content (100 vol%) of the composition is also listed.

[0256] The details of each material described in Table 1 are as follows.

[0257] Vinylbenzyl compound X: prepared by the above method

[0258] Acenaphthene polymer Y1: prepared by the above method

[0259] Acenaphthene polymer Y2: prepared by the above method

[0260] Flame retardant: Phosphorus flame retardant

[0261] Inorganic filler: silicon dioxide (average particle size: 1 μm)

[0262] [Preparation of prepreg]

[0263] The resin composition (varnish) obtained as described above was impregnated and coated on a NE glass cloth (manufactured by Nitto Bosho Co., Ltd.) having a thickness of 0.03 mm, and heated and dried at 130° C. for 10 minutes to obtain a prepreg. In the prepreg of Comparative Example 1, the content of the solid component derived from the resin composition was 91% by mass relative to the prepreg. In the prepregs of Examples 1 and 2, the content of the solid component derived from the resin composition was 90% by mass relative to the prepreg. In the prepregs of Comparative Example 2 and Example 3, the content of the solid component derived from the resin composition was 81% by mass and 77% by mass relative to the prepreg, respectively.

[0264] [Manufacturing of double-sided copper-clad laminate]

[0265] Electrolytic copper foil ("SI-VSP-AM-3R" (trade name) manufactured by Mitsui Mining and Smelting Co., Ltd.) with a thickness of 18 μm was overlapped on both sides of the prepreg obtained as described above so that the matte surface overlapped with the prepreg, and heated and pressed at 230°C under vacuum pressing conditions of 2 MPa for 120 minutes to produce a double-sided copper-clad laminate.

[0266] [Evaluation method and measurement method]

[0267] Evaluation and measurement were performed as described below.

[0268] <Sublimation of Acenaphthene Monomer and Acenaphthene Polymer Y1>

[0269] The acenaphthene monomer and acenaphthene homopolymer Y1 solids used to produce the acenaphthene polymer Y1 were heated to 30 to 1000°C at 20°C / min in a nitrogen atmosphere using TG-DTA (manufactured by Hitachi High-Technologies Corporation, device name: STA7200) to evaluate the thermal weight loss behavior. The evaluation criteria for sublimation are as follows: in the above measurement results, a 5 wt% weight loss temperature (Td5) of less than 200°C is recorded as sublimation, and a temperature of 200°C or more is recorded as non-sublimation.

[0270] The Td5 of the acenaphthene monomer was 140°C, which was evaluated as having sublimation properties. On the other hand, the Td5 of the acenaphthene polymer Y1 was 380°C, which was evaluated as having no sublimation properties.

[0271] <Dielectric properties (relative dielectric constant (Dk) and dielectric loss tangent (Df)>

[0272] The double-sided copper-clad laminate obtained as described above was immersed in a 10 mass % solution of ammonium persulfate (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a copper etching solution to remove the copper foil, and an evaluation substrate of 60 mm×100 mm was cut out from the substrate from which the copper foil was removed.

[0273] The evaluation substrate was dried at 105° C. for 1 hour and then allowed to stand for 24 hours, and then measured as follows.

[0274] Using the evaluation substrate, the relative dielectric constant (Dk) and dielectric loss tangent (Df) were measured in a 10 GHz band at 25° C. according to the SPDR method (separated pin dielectric resonator). The measurement apparatus used was “PNA Network Analyzer N5227A” (trade name) from Agilent Technologies. The results are shown in Table 1.

[0275] <Flame retardancy>

[0276] The double-sided copper-clad laminate obtained as described above was used to carry out a flammability test.

[0277] The double-sided copper-clad laminate was immersed in a 10 mass % solution of ammonium persulfate (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a copper etching solution to remove the copper foil, and an evaluation substrate of 13 mm×125 mm was cut out from the substrate from which the copper foil was removed.

[0278] According to the vertical combustion test (UL94-V), the upper end of the evaluation substrate is held, and the flame of the gas burner is vertically contacted with the lower end of the evaluation substrate for 10 seconds. If the flame disappears after the gas burner flame is removed, the gas burner flame is immediately contacted for another 10 seconds and then the flame is removed. The average burning time after the flame is removed is calculated. It should be noted that the vertical combustion test is evaluated for one test number with N=5.

[0279] In the "Ratio of average burning time relative to comparative example" in the table, the ratio (%) of the average burning time of Examples 1 and 2 when the average burning time of Comparative Example 1 not containing an acenaphthene polymer is set to 100%, and the ratio (%) of the average burning time of Example 3 when the average burning time of Comparative Example 2 not containing an acenaphthene polymer is set to 100% are recorded.

[0280] [Table 1]

[0281]

[0282] As described above, it was determined that the acenaphthene polymer Y1 had no sublimation property. In addition, as shown in Table 1, in the evaluation of flame retardancy, the ratio of the average burning time of Examples 1 to 3 using the acenaphthene polymer Y1 or Y2 to the corresponding comparative example was reduced, indicating that the average burning time was shorter than the average burning time of the corresponding comparative example, and had good flame retardancy. In addition, Examples 1 to 3 showed good dielectric properties.

[0283] Description of Reference Numerals

[0284] 1: Metal foil

[0285] 2: Cured prepreg

[0286] 10: Metal-clad laminate.

Claims

1. A resin composition comprising (A) a thermosetting resin and (B) an acenaphthene polymer having a number average molecular weight of 1,000 or more.

2. The resin composition according to claim 1, wherein the acenaphthene polymer (B) having a number average molecular weight of 1,000 or more is 5% by mass or more relative to the total amount of the (A) thermosetting resin and the (B) acenaphthene polymer having a number average molecular weight of 1,000 or more. 3 . The resin composition according to claim 1 , wherein the (A) thermosetting resin comprises a compound having a vinylbenzyl group. 4 . A prepreg formed using the resin composition according to claim 1 . 5 . A resin film formed using the resin composition according to claim 1 . 6 . A metal-clad laminate comprising a cured product of the resin composition according to claim 1 and a metal foil.

7. A metal-clad laminate formed by using the prepreg according to claim 4 and a metal foil. 8 . A printed wiring board comprising a cured product of the resin composition according to claim 1 . 9 . A semiconductor package comprising the printed wiring board according to claim 8 and a semiconductor element.

10. An acenaphthene homopolymer having a number average molecular weight greater than or equal to 1,000.

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