TWI905094B - Resin compositions, prepregs, metal foil laminates, resin composites, and printed wiring boards - Google Patents

Abstract

This invention expands the range of materials suitable for use as prepregs in printed circuit boards by providing a resin composition with a novel composition containing a specific maleimide compound. Furthermore, this invention provides a resin composition in which, in terms of physical properties, the dielectric constant and dielectric loss tangent are suppressed to sufficiently low values, and the changes in dielectric constant and dielectric loss tangent after long-term heating are also suppressed to sufficiently low values, resulting in excellent peel resistance when fabricated into films and sheets, and practically sufficient heat resistance; and provides prepregs, metal foil laminates, resin composites, and printed circuit boards using this resin composition. A resin composition comprising a polyfunctional vinyl aromatic polymer (A) and a specific maleimide compound (B).

Description

Resin compositions, prepregs, metal foil laminates, resin composites, and printed wiring boards

This invention relates to resin compositions, and prepregs, metal foil laminates, resin composites, and printed wiring boards using the resin compositions.

In recent years, the hyper-integration and miniaturization of semiconductor components used in electronic devices and communication equipment, primarily mobile terminals, have accelerated. Along with this, there is a growing demand for technologies enabling high-density mounting of semiconductor components, as well as for improvements to printed circuit boards (PCBs), which occupy a crucial position within these systems. On the other hand, the applications of electronic devices are becoming increasingly diverse and expanding. Consequently, the requirements for the characteristics of PCBs, the metal-clad laminates used in them, and the prepregs are becoming more diverse and demanding. Considering these requirements and in order to obtain improved PCBs, various materials and processing methods have been proposed. One example is the development and improvement of resin materials that constitute the prepreg.

For example, Patent 1 discloses a resin composition containing: a terminal vinyl compound of a difunctional polyphenylene ether oligomer having a polyphenylene ether backbone (a), a specific maleimide compound (b), a naphthol aralkyl cyanate resin (c), and a phenolic varnish-type epoxy resin modified with a naphthol backbone (d).

Patent document 2 discloses a flame-retardant resin composition, which is composed of a resin having at least one maleimide group at one end (an amino-bismaleimide resin using N,N'-4,4'-diphenylmethane bismaleimide and diamine as raw materials), and a copolymer of brominated styrene represented by formula (c1) and divinylbenzene represented by formula (c2). [Chemical 1] [Previous Art Documents] [Patent Documents]

[Patent Document 1] Japanese Patent Application Publication No. 2010-138364 [Patent Document 2] Japanese Patent Application Publication No. Hei 03-006293

[The problem the invention aims to solve]

Including the examples above, improvements have been made to various properties in semiconductor manufacturing processes through material development. However, given recent technological advancements and expanded applications, there is a demand for further expansion of material selection and further improvements in performance and manufacturing suitability. Therefore, the object of this invention is to expand the range of materials ideally suited for use as prepregs in printed circuit boards by providing resin compositions with novel compositions containing specific maleimide compounds. Furthermore, this invention aims to provide a resin composition in which, in terms of physical properties, the dielectric constant and dielectric loss tangent are suppressed to sufficiently low values, and the changes in dielectric constant and dielectric loss tangent after long-term heating are also suppressed to sufficiently low values. This results in excellent peel resistance when fabricated into films and sheets, and practically sufficient heat resistance. The invention also aims to provide prepregs, metal foil laminates, resin composites, and printed circuit boards using this resin composition. [Means for Solving the Problem]

Based on the aforementioned problems, the inventors of this invention, through research, discovered that by combining maleimide compounds with specific structures with polyfunctional vinyl aromatic polymers, the aforementioned problems can be solved, thus completing this invention. Specifically, the aforementioned problems were solved using the following means>1>, preferably>2> to>10>.

>1> A resin composition comprising a polyfunctional vinyl aromatic polymer (A) and a maleimide compound (B), wherein at least one compound represented by any one of formulas (1) to (4) is the aforementioned maleimide compound (B). [Chemistry 2] In formula (1), ^R1 , ^R2 , ^R3 , and ^R4 each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group, and n1 represents a number between 1 and 10. [Chemistry 3] In formula (2), ^R6 independently represents either a methyl or ethyl group, and ^R7 independently represents either a hydrogen atom or a methyl group. [Chemistry 4] In formula (3), ^R8 independently represents a hydrogen atom, a methyl group, or an ethyl group. [Chemistry 5] In formula (4), ^R9 independently represents a hydrogen atom, a methyl group, or an ethyl group. >2> Resin compositions as in >1>, wherein the aforementioned multifunctional vinyl aromatic polymer (A) is a polymer having the constituent units represented by formula (V). [Chemical 6] In formula (V), Ar represents an aromatic hydrocarbon linker. * indicates a bonding position. >3> A resin composition as described in >1> or >2>, wherein the content of the aforementioned maleimide compound (B) is 5 to 95 parts by mass relative to 100 parts by mass of the total resin components in the resin composition. >4> A resin composition as described in any of >1> to >3>, wherein the content of the aforementioned polyfunctional vinyl aromatic polymer (A) is 5 to 95 parts by mass relative to 100 parts by mass of the total resin components in the resin composition. >5> A resin composition as described in any of >1> to >4> further contains a filler (C). >6> A resin composition as described in >5>, wherein the content of the aforementioned filler (C) is 10 to 500 parts by mass relative to 100 parts by mass of the total amount of resin components in the resin composition. >7> A prepreg formed from a substrate and a resin composition as described in >1> to >6>. >8> A metal foil laminate comprising: at least one layer formed from a prepreg as described in >7>; and a metal foil disposed on one or both sides of the aforementioned layer formed from the prepreg. >9> A resin composite sheet comprising: a support; and a layer formed from a resin composition as described in >1> to >6> disposed on the surface of the aforementioned support. >10> A printed wiring board includes: an insulating layer; and a conductor layer disposed on the surface of the insulating layer; the insulating layer includes at least one of a layer formed of a resin composition as described in >1> to >6> and a layer formed of a prepreg as described in >7>. [Effects of the Invention]

According to the present invention, by providing a resin composition with a novel component composition in a resin composition containing a specific maleimide compound, the range of materials that can be ideally used for prepregs can be expanded. Furthermore, a resin composition can be provided whose dielectric constant and dielectric loss tangent are suppressed to sufficiently low values, and whose changes in dielectric constant and dielectric loss tangent after long-term heating are also suppressed to sufficiently low values. This results in excellent peel resistance to the conductor layer (metal foil) when fabricated into films or sheets, and practically sufficient heat resistance (high glass transition temperature). Prepregs, metal foil laminates, resin composites, and printed circuit boards using this resin composition can be provided.

The contents of this invention will be explained in detail below. In addition, in this specification, "~" is used to mean the lower limit and upper limit value, including the numerical value recorded before and after it.

The resin composition of this embodiment is characterized by containing a multifunctional vinyl aromatic polymer (A) and a maleimide compound (B), wherein at least one compound represented by any one of the following formulas (1) to (4) is used as the aforementioned maleimide compound (B). By having such a configuration, a resin composition with sufficiently low dielectric constant and dielectric loss tangent, and with sufficiently low changes in dielectric constant and dielectric loss tangent after long-term heating, exhibits excellent peel resistance when fabricated into films or sheets, and possesses practically sufficient heat resistance. [Chemical 7] In formula (1), ^R1 , ^R2 , ^R3 , and ^R4 each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group, and n1 represents a number between 1 and 10. [Chemistry 8] In formula (2), ^R6 independently represents either a methyl or ethyl group, and ^R7 independently represents either a hydrogen atom or a methyl group. [Chemistry 9] In formula (3), ^R8 independently represents a hydrogen atom, a methyl group, or an ethyl group. [Chemistry 10] In formula (4), ^R9 each independently represents a hydrogen atom, a methyl group, or an ethyl group. Furthermore, the resin composition of this embodiment is preferably a non-photosensitive thermosetting resin composition that is cured primarily by heat rather than by light.

>Multifunctional Vinyl Aromatic Polymer (A)> The resin composition of this embodiment contains a multifunctional vinyl aromatic polymer (A). The multifunctional vinyl aromatic polymer (A) is preferably a polymer obtained by polymerizing an aromatic compound having two or more vinyl groups within its molecule. The aromatic compound having two or more vinyl groups within its molecule can be, for example, any of the positional isomers of vinyl groups, or a mixture of such positional isomers. More specifically, when the multifunctional vinyl aromatic polymer (A) is an aromatic compound having two vinyl groups within its molecule, it can be any of a meta-, para-, ortho-, or mixture of such positional isomers, and preferably any of a meta-, para-, or mixture of such positional isomers. As monomers constituting the polyfunctional vinyl aromatic polymer (A), examples can be listed of aromatic compounds having one or more vinyl groups (hereinafter, aromatic compounds having two or more vinyl groups are also referred to as polyfunctional vinyl aromatic compounds), preferably aromatic compounds having one or two vinyl groups. For example, with regard to the polyfunctional vinyl aromatic polymer (A), examples can be shown of polymers containing a constituent unit (a) derived from an aromatic compound having two vinyl groups (also referred to as a divinyl aromatic compound) and a constituent unit (b) derived from an aromatic compound having one vinyl group.

The divinyl aromatic compound forming the constituent unit (a) is preferably a compound having an aromatic hydrocarbon ring, such as: divinylbenzene, diallylbenzene, bis(vinyloxy)benzene, bis(1-methylvinyl)benzene, divinylnaphthalene, divinylanthracene, divinylbiphenyl, divinylphenanthrene, bis(4-allyloxyphenyl)furan, etc. Divinylbenzene is particularly preferred. The form of the constituent unit from the divinyl aromatic compound in the polymer can be (a-1) a form in which only one vinyl group undergoes polymerization, while the other vinyl group remains unreacted; and (a-2) a form in which both vinyl groups undergo polymerization. In this embodiment, the form in which one vinyl group remains unreacted (a-1) is preferred. Furthermore, the polyfunctional vinyl aromatic compound (preferably a divinyl aromatic compound) may also have any substituent Z (e.g., alkyl with 1 to 6 carbons, alkenyl with 2 to 6 carbons, alkynyl with 2 to 6 carbons, alkoxy with 1 to 6 carbons, hydroxyl, amino, carboxyl, halogen atom, etc.) within the scope of achieving the effects of the present invention.

The aforementioned constituent unit (a) derived from a polyfunctional vinyl aromatic compound (preferably a divinyl aromatic compound) preferably includes a constituent unit represented by the following formula (V). [Chemistry 11] In formula (V), Ar represents an aromatic hydrocarbon linker. Specific examples include the following ^L1 example. The asterisk (*) in the formula indicates the bonding position. The aromatic hydrocarbon linker can be a base composed solely of aromatic hydrocarbons that may also have substituents, or a base composed of a combination of aromatic hydrocarbons that may also have substituents and other linkers; preferably, it should be a base composed solely of aromatic hydrocarbons that may also have substituents. Furthermore, the aromatic hydrocarbon may also have substituents, as exemplified by the aforementioned substituent Z. Also, the aforementioned aromatic hydrocarbon should preferably not have substituents. Aromatic hydrocarbon linkers are typically divalent linkers.

Aromatic hydrocarbon linkers can specifically include, but may also have substituents, such as phenyl, naphthyl, anthracenediyl, phenanthrenediyl, biphenyldiyl, and fumaridyl, among which phenyl, which may also have substituents, is preferred. Substituents can be exemplified by the above-mentioned substituent Z, and the above-mentioned phenyl groups should preferably not have substituents.

The constituent unit (a) of the polyfunctional vinyl aromatic compound (preferably a divinyl aromatic compound) preferably includes at least one of the constituent unit represented by formula (V1), the constituent unit represented by formula (V2), and the constituent unit represented by formula (V3). In addition, * in the formula indicates a bond position.

[Chemistry 12] In formulas (V1) to (V3), ^L1 is an aromatic hydrocarbon linker (preferably with 6 to 22 carbon atoms, more preferably 6 to 18, and especially preferably 6 to 10). Specifically, examples that may also have substituents include phenyl, naphthyl, anthracenediyl, phenanthrenediyl, biphenyldiyl, and fumaridyl, among which phenyl may preferably have substituents. Substituents can be exemplified by the above-mentioned substituent Z, and the above-mentioned phenyl groups should preferably not have substituents.

The multifunctional vinyl aromatic polymer (A), as described above, can be a homopolymer of constituent unit (a) or a copolymer with constituent unit (b), etc. When the multifunctional vinyl aromatic polymer (A) is a copolymer, in terms of its copolymerization ratio, constituent unit (a) is preferably 5 mol% or more, more preferably 10 mol% or more, and especially preferably 15 mol% or more. The upper limit is actually 90 mol% or less.

When the multifunctional vinyl aromatic polymer (A) is a copolymer containing a constituent unit (b) derived from a monovinyl aromatic compound, examples of monovinyl aromatic compounds include: vinyl aromatic compounds such as styrene, vinylnaphthalene, and vinyl biphenyl; alkyl-substituted vinyl aromatic compounds such as ortho-methylstyrene, m-methylstyrene, p-methylstyrene, ortho- and p-dimethylstyrene, ortho-ethylvinylbenzene, m-ethylvinylbenzene, p-ethylvinylbenzene, methylvinyl biphenyl, and ethylvinyl biphenyl. The monovinyl aromatic compounds exemplified herein may also appropriately have the aforementioned substituent Z. Furthermore, one or more of these monovinyl aromatic compounds may be used.

The constituent unit (b) derived from the monovinyl aromatic compound shall preferably be represented by the following formula (V4).

[Chemistry 13] In formula (V4), ^L2 is an aromatic hydrocarbon linker, and a preferred example is the ^L1 example mentioned above. ^RV1 is a hydrogen atom or a hydrocarbon with 1 to 12 carbon atoms (preferably an alkyl group). When ^RV1 is a hydrocarbon, it is preferably 1 to 6 carbon atoms, and 1 to 3 carbon atoms are more preferred. ^RV1 and ^L2 may also have the substituent Z mentioned above.

When the multifunctional vinyl aromatic polymer (A) is a copolymer containing constituent unit (b), the copolymerization ratio of constituent unit (b) is preferably 10 mol% or more, and more preferably 15 mol% or more. The upper limit is preferably 98 mol% or less, more preferably 90 mol% or less, and especially preferably 85 mol% or less.

Multifunctional vinyl aromatic polymers (A) may also have other constituent units. Examples of other constituent units include constituent units derived from cyclic alkenes (c). Cyclic alkenes include hydrocarbons with double bonds within their ring structures. Specifically, monocyclic cyclic alkenes such as cyclobutene, cyclopentene, cyclohexene, and cyclooctene can be listed, as well as compounds with nocamphene ring structures such as norcamphene and dicyclopentadiene, and cyclic alkenes obtained by the condensation of aromatic rings such as indene and vinylnaphthalene. Examples of norcamphene compounds can be found in paragraphs 0037 to 0043 of Japanese Patent Application Publication No. 2018-39995, the contents of which are incorporated herein by reference. Furthermore, the cyclic olefin compounds illustrated herein may also have the aforementioned substituent Z.

When the multifunctional vinyl aromatic polymer (A) is a copolymer containing the constituent unit (c), the copolymerization ratio of the constituent unit (c) is preferably 10 mol% or more, more preferably 20 mol% or more, and especially preferably 30 mol% or more. The upper limit is preferably 90 mol% or less, more preferably 80 mol% or less, especially preferably 70 mol% or less, and can also be 50 mol% or less, or 30 mol% or less.

The multifunctional vinyl aromatic polymer (A) may also include constituent units (d) from different polymeric compounds (hereinafter also referred to as other polymeric compounds). Examples of other polymeric compounds (monomers) include compounds containing three vinyl groups. Specifically, examples include 1,3,5-trivinylbenzene, 1,3,5-trivinylnaphthalene, and 1,2,4-trivinylcyclohexane. Or examples include ethylene glycol diacrylate and butadiene. The copolymerization ratio of constituent units (d) from other polymeric compounds should preferably be 30 mol% or less, more preferably 20 mol% or less, and especially preferably 10 mol% or less.

As one embodiment of the multifunctional vinyl aromatic polymer (A), an example is a polymer in which constituent unit (a) is an essential constituent unit and contains at least one of constituent units (b) to (d). Alternatively, an example is a polymer in which the sum of constituent units (a) to (d) accounts for 95 mol% or more, and further 98 mol% or more, of all constituent units. As another embodiment of the multifunctional vinyl aromatic polymer (A), it is preferable that constituent unit (a) is an essential constituent unit, and that constituent units containing aromatic rings account for 90 mol% or more of all constituent units excluding the terminal units, more preferably 95 mol% or more, and possibly 100 mol%. When calculating the mol% of each total constituent unit, one constituent unit is derived from one molecule of the monomer constituting the multifunctional vinyl aromatic polymer (A).

There are no particular limitations on the manufacturing method of the multifunctional vinyl aromatic polymer (A), and any conventional method can be used. For example, monomers containing divinyl aromatic compounds (with monovinyl aromatic compounds, cycloene compounds, etc., coexisting as needed) can be polymerized in the presence of a Lewis acid catalyst. The Lewis acid catalyst can be a metal fluoride or its complex.

The structure of the chain ends of the polyfunctional vinyl aromatic polymer (A) is not particularly limited, and the base derived from the above-mentioned divinyl aromatic compound can take the structure of the following formula (E1). Furthermore, ^L1 in formula (E1) is the same as that specified in formula (V1) above. * indicates the bond position. * -CH=CH- ^L1 -CH= _CH2 (E1)

When the chain terminator is a monovinyl aromatic compound, the structure of formula (E2) can be listed. ^L2 and ^RV1 in this formula have the same meaning as defined in formula (V4). * indicates the bond position. * -CH=CH- ^{L2 -RV1} (E2)

The molecular weight of the polyfunctional vinyl aromatic polymer (A), expressed as a number average molecular weight Mn, is preferably 300 or higher, more preferably 500 or higher, and especially preferably 1,000 or higher. The upper limit is preferably 100,000 or lower, more preferably 10,000 or lower, especially preferably 5,000 or lower, and even more preferably 4,000 or lower. The monodispersity (Mw/Mn), expressed as the ratio of weight average molecular weight Mw to number average molecular weight Mn, is preferably 100 or lower, more preferably 50 or lower, and especially preferably 20 or lower. The lower limit is practically 1.1 or higher. The polyfunctional vinyl aromatic polymer (A) is preferably soluble in toluene, xylene, tetrahydrofuran, dichloroethane, or chloroform.

In this specification, regarding the multifunctional vinyl aromatic polymer (A), please refer to the compounds and their synthesis reaction conditions described in paragraphs 0029 to 0058 of International Publication No. 2017/115813, the compounds and their synthesis reaction conditions described in paragraphs 0013 to 0058 of Japanese Patent Application Publication No. 2018-039995, and the compounds and their synthesis reaction conditions described in paragraphs 0008 to 0043 of Japanese Patent Application Publication No. 2018-168347. The contents of the following are included in this specification: reaction conditions, compounds and their synthesis reaction conditions as described in paragraphs 0014 to 0042 of Japanese Patent Application Publication No. 2006-070136, compounds and their synthesis reaction conditions as described in paragraphs 0014 to 0061 of Japanese Patent Application Publication No. 2006-089683, and compounds and their synthesis reaction conditions as described in paragraphs 0008 to 0036 of Japanese Patent Application Publication No. 2008-248001.

Regarding the content of the multifunctional vinyl aromatic polymer (A), when the total amount of resin components in the resin composition is 100 parts by mass, it is preferable to have 5 parts by mass or more, preferably 10 parts by mass or more, especially 15 parts by mass or more, and even more preferably 20 parts by mass or more. Alternatively, it can also be 30 parts by mass or more, 40 parts by mass or more, 50 parts by mass or more, or 60 parts by mass or more. By having the content of the multifunctional vinyl aromatic polymer (A) at or above the above-mentioned lower limit, a low dielectric constant and a low dielectric loss tangent (especially a low dielectric constant) can be effectively achieved. On the other hand, regarding the upper limit of the content of the polyfunctional vinyl aromatic polymer (A), when the total amount of resin components in the resin composition is 100 parts by weight, it is preferable to be 95 parts by weight or less, more preferably 90 parts by weight or less, especially 85 parts by weight or less, and even more preferably 80 parts by weight or less; 70 parts by weight or less is also acceptable. The resin composition may contain only one type of polyfunctional vinyl aromatic polymer (A), or it may contain two or more types. When it contains two or more types, the total amount should preferably be within the above-mentioned range. Furthermore, the resin composition includes the polyfunctional vinyl aromatic polymer (A) and the maleimide compound (B), as well as other resin components described later.

>Maleimimine compound (B)> The maleimimine compound (B) used in the resin composition of this embodiment includes compounds represented by any one of formulas (1) to (4). [Chemical 14] In formula (1), ^R1 , ^R2 , ^R3 , and ^R4 each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group, and n1 represents a number between 1 and 10. In formula (1), ^R1 , ^R2 , ^R3 , and ^R4 are preferably methyl, ethyl, phenyl, or hydrogen atoms, with hydrogen atoms being more preferred. n1 represents a number between 1 and 10, with a number between 1 and 4 being more preferred. It may also contain two or more compounds with different n1 values.

[Chemistry 15] In formula (2), each ^{of R6} independently represents a methyl or ethyl atom, and each of ^R7 independently represents a hydrogen atom or a methyl atom. It is preferable that 1 to 3 of the 4 ^R6s are methyl and the remaining 3 to 1 are ethyl, and even more preferable that 2 of the 4 ^R6s are methyl and the remaining 2 are ethyl. It is particularly preferred that the two ^R6s substituted on the two aromatic rings are methyl and ethyl, respectively.

[Chemistry 16] In formula (3), ^R8 independently represents a hydrogen atom, a methyl atom, or an ethyl atom. ^R8 is preferably a methyl atom or an ethyl atom, with methyl being more preferred.

[Chemistry 17] In formula (4), ^R9 independently represents a hydrogen atom, a methyl atom, or an ethyl atom. ^R9 is preferably methyl or ethyl, with methyl being more preferred.

The equivalent of unsaturated amide groups in maleimide compound (B) should preferably be 200 g/eq or more and preferably 400 g/eq or less. When two or more maleimide compounds (B) are contained, the equivalent of unsaturated amide groups is taken into account by considering the weight-average mass of each maleimide compound (B) contained in the resin composition.

Regarding the content of maleimide compound (B), when the total amount of resin components in the resin composition is 100 parts by weight, it is preferable to have 5 parts by weight or more, preferably 10 parts by weight or more, especially 15 parts by weight or more, and even more preferably 20 parts by weight or more, and it can also be 30 parts by weight or more. By having the content of maleimide compound (B) at or above the above-mentioned lower limit, there is a tendency for peel strength and heat resistance to be improved. On the other hand, regarding the upper limit of the content of maleimide compound (B), when the total amount of resin components in the resin composition is 100 parts by weight, it is preferable to be 95 parts by weight or less, more preferably 90 parts by weight or less, especially 85 parts by weight or less, and even more preferably 80 parts by weight or less. Further, it is also permissible to be 70 parts by weight or less, 60 parts by weight or less, 50 parts by weight or less, or 40 parts by weight or less. One type of maleimide compound (B) may be used, or two or more types may be used. When two or more types are used, their total amount shall be within the above-mentioned range.

In this invention, the effects of the invention are particularly enhanced by setting the amount of maleimide compound (B) relative to the polyfunctional vinyl aromatic polymer (A) to an appropriate level. Specifically, the dielectric constant and dielectric loss tangent can be maintained at a low level, while high heat resistance and peel strength can be achieved. In view of this effect, the content of maleimide compound (B) relative to the content of polyfunctional vinyl aromatic polymer (A) is preferably 6 parts by mass or more, more preferably 11 parts by mass or more, and especially preferably 25 parts by mass or more. The upper limit is preferably 1900 parts by mass or less, more preferably 900 parts by mass or less, and especially preferably 400 parts by mass or less.

When the resin composition of this embodiment does not contain the filler (C) described later, the resin content preferably accounts for 90% or more by mass of the resin composition, more preferably 95% or more by mass, and even more preferably 98% or more by mass. When the resin composition of this embodiment contains the filler (C), the resin content preferably accounts for 15% or more by mass of the resin composition, more preferably 20% or more by mass, and even more preferably 30% or more by mass. Furthermore, regarding the upper limit, the resin content preferably accounts for less than 90% by mass of the resin composition, more preferably less than 85% by mass, and even more preferably less than 80% by mass.

>Fill (C)> To improve low dielectric constant, low dielectric loss tangent, flame retardancy, and low thermal expansion, the resin composition of this embodiment preferably contains a filler (C), which is preferably an inorganic filler. The filler (C) used may be any known type, and there are no particular limitations on its type; it is ideally suited for use by common users in the field. Specifically, the following types of silica can be listed: natural silica, fused silica, synthetic silica, amorphous silica, silica aerosol, hollow silica, and other silica compounds; white carbon black, titanium dioxide, zinc oxide, magnesium oxide, zirconium oxide, boron nitride, condensed boron nitride, silicon nitride, aluminum nitride, barium sulfate, aluminum hydroxide, heat-treated aluminum hydroxide (obtained by heating aluminum hydroxide to remove some of its water of crystallization), soft bauxite, magnesium hydroxide, and other metal hydrates; molybdenum oxide, zinc molybdate, and other molybdenum compounds; zinc borate, zinc stannate, aluminum oxide, and clay. Inorganic fillers include: kaolin, talc, calcined clay, calcined kaolin, calcined talc, mica, E-glass, A-glass, NE-glass, C-glass, L-glass, D-glass, S-glass, M-glass G20, glass short fibers (including glass micropowders of E-glass, T-glass, D-glass, S-glass, Q-glass, etc.), insulated glass, and spherical glass; other fillers include styrene-based, butadiene-based, acrylic-based rubber powders, core-shell rubber powders, polysiloxane resin powders, polysiloxane rubber powders, and polysiloxane composite powders, etc., which are organic fillers. Of these, one or more of the following are preferred: silica, aluminum hydroxide, bauxite, magnesium oxide, and magnesium hydroxide; silica is the most desirable. The silica should preferably be spherical. Spherical silica can also be hollow silica. Using these fillers improves the thermal expansion characteristics, dimensional stability, and flame retardancy of the resin composition.

The content of filler (C) in the resin composition of this embodiment can be appropriately set according to the desired characteristics and is not particularly limited. When the total amount of resin components in the resin composition is 100 parts by weight, it is preferable to be 10 parts by weight or more, preferably 20 parts by weight or more, especially 30 parts by weight or more, and also 50 parts by weight or more. The upper limit is preferably 500 parts by weight or less, preferably 400 parts by weight or less, especially 300 parts by weight or less, even more preferably 250 parts by weight or less, and also 200 parts by weight or less. One type of filler (C) may be used, or two or more types may be used. When two or more types are used, their total amount should preferably be within the above range.

>Other Resin Components> The resin composition of this embodiment may also contain other resin components besides the aforementioned multifunctional vinyl aromatic polymer (A) and maleimide compound (B). Examples of other resin components include maleimide compounds other than the aforementioned maleimide compound (B), epoxy resins, phenolic resins, and cyanate compounds (e.g., phenolic varnish-type cyanate compounds, naphthol aralkyl-type cyanate compounds, biphenyl aralkyl-type cyanate compounds, naphthyl ether-type cyanate compounds, xylene resin-type cyanate compounds, and diamond skeleton-type cyanate compounds). The resin composition comprises one or more compounds, including bisphenol A cyanate compounds, diallyl bisphenol A cyanate compounds, bisphenol M cyanate compounds, nadicliimide compounds, oxadiazine resins, benzo[a]pyrene compounds, compounds having polymerizable unsaturated groups, modified polyphenylene ethers end-modified with substituents containing carbon-carbon unsaturated double bonds, elastomers, and active ester compounds. When the resin composition of this embodiment contains other resin components, their content is preferably 1 to 30 parts by weight, for example, relative to 100 parts by weight of the resin component. Furthermore, in the resin composition of this embodiment, the total content of the polyfunctional vinyl aromatic polymer (A) and the maleicimine compound (B) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and most preferably 80% by mass or more.

>Cure Accelerator (Catalyst)> The resin composition of this embodiment may further contain a cure accelerator. The cure accelerator is not particularly limited, and examples include: organometallic salts (e.g., zinc octanoate, zinc cycloalkanoate, cobalt cycloalkanoate, copper cycloalkanoate, acetoacetone iron, nickel octanoate, manganese octanoate, etc.), phenolic compounds (e.g., phenol, xylenol, cresol, resorcinol, orthoquinone, octylphenol, nonylphenol, etc.), alcohols (e.g., 1-butanol, 2-ethylhexanol, etc.), imidazoles (e.g., 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl- 2-Ethyl-4-methylimidazolium, 2-phenyl-4,5-dihydroxymethylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium, etc.), and their carboxylic acid or anhydride adducts and other derivatives, amines (e.g., dicyandiamide, benzyldimethylamine, 4-methyl-N,N-dimethylbenzylamine, etc.), phosphorus compounds (e.g., phosphine compounds, phosphine oxide compounds, phosphonium salt compounds, diphosphine compounds, etc.), and epoxy-imidazolium adduct compounds. The hardening accelerator is preferably an imidazolium compound or an organometallic salt, with imidazolium compounds being more preferred.

When a curing accelerator is included, the lower limit of the curing accelerator content, relative to 100 parts by weight of the total resin components in the resin composition, is preferably 0.005 parts by weight or more, more preferably 0.01 parts by weight or more, and even more preferably 0.1 parts by weight or more. Furthermore, the upper limit of the aforementioned curing accelerator content, relative to 100 parts by weight of the total resin components in the resin composition, is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, and even more preferably 2 parts by weight or less. A curing accelerator may be used alone or in combination with two or more. When two or more are used, the total amount shall be within the range described above.

>Soluble> The resin composition of this embodiment may also contain a solvent, preferably an organic solvent. In this case, the resin composition of this embodiment is at least a portion of the various resin components mentioned above, preferably in a form that is completely dissolved in the solvent or miscible with the solvent (solution or varnish). Regarding the solvent, there are no particular limitations as long as it is a polar or non-polar organic solvent that can dissolve at least a portion of, preferably all or miscible with, the aforementioned resin components. Examples of polar organic solvents include: ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), cyrosols (e.g., propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc.), esters (e.g., ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate, methyl methoxypropionate, methyl hydroxyisobutyrate, etc.), and amides (e.g., dimethoxyacetamide, dimethylformamide, etc.). Examples of non-polar organic solvents include aromatic hydrocarbons (e.g., toluene, xylene, etc.). Solvents can be used alone or in combination of two or more.

>Other Ingredients> In addition to the above-mentioned ingredients, the resin composition of this embodiment may also contain, to the extent that it does not impair the effects of the invention, flame retardants, ultraviolet absorbers, antioxidants, polymerization initiators (which may be any of photopolymerization initiators, thermal polymerization initiators, free radical polymerization initiators, or cationic polymerization initiators), fluorescent whitening agents, photosensitizers, dyes, pigments, thickeners, flow modifiers, lubricants, defoamers, dispersants, leveling agents, gloss agents, polymerization inhibitors, silane coupling agents, etc. These additives may be used alone or in combination of two or more.

Properties of the Resin Composition> When the resin composition of this embodiment is formed into a 1.6 mm thick plate-like cured material, the relative permittivity (Dk) at 10 GHz can be set to 2.7 or less, or 2.6 or less, or 2.5 or less. Ideally, the lower limit of the aforementioned permittivity should be 1.0, but in practice it is 2.1 or more. Furthermore, when the resin composition of this embodiment is formed into a 1.6 mm thick plate-like cured material, the dielectric loss tangent (Df) at 10 GHz can be set to 0.0040 or less, or 0.0020 or less, or 0.0015 or less. Ideally, the lower limit of the aforementioned dielectric loss tangent should be 0, but in practice it is 0.0005 or more. The dielectric constant and dielectric loss tangent were determined using the method described in the embodiments below.

When the resin composition of this embodiment is molded into a 1.6 mm thick plate-like cured material, the glass transition temperature can be set to 200°C or higher, 220°C or higher, or 300°C or higher. There is no specific upper limit for the aforementioned glass transition temperature; it is below 400°C, and more specifically, below 350°C. The glass transition temperature is measured using the method described in the embodiments below.

>Manufacturing Method of Resin Composition> The resin composition of this embodiment can be manufactured by conventional methods. For example, a mixture of a multifunctional vinyl aromatic polymer (A) and a maleimide compound (B) can be used. The ideal content is as described above. Furthermore, in the resin composition of this embodiment, fillers (C), other resin components, and other additives can be appropriately coexisted and mixed. The appearance can also be improved or other properties can be enhanced by admixture with other resin components. One example of the resin composition of this embodiment is a solvent-containing varnish. Another example of the resin composition of this embodiment is a sheet-like hardened material or a film. Additionally, the resin composition of this embodiment is ideally suited for the applications described later.

Applications > The resin composition of this embodiment can be used as a curing agent. Specifically, the resin composition of this embodiment, as a low dielectric constant material and/or a low dielectric loss tangent material, is ideally suited for use as an insulating layer for printed circuit boards and a semiconductor packaging material. The resin composition of this embodiment is ideally suited for use as a material constituting a prepreg, a metal-clad laminate formed from the prepreg, a resin composite sheet, and a printed circuit board. When the resin composition of this embodiment is used to manufacture layered articles, its thickness is preferably 5 μm or more, and more preferably 10 μm or more. The upper limit is preferably 2 mm or less, and more preferably 1 mm or less. Furthermore, regarding the thickness of the aforementioned layered molded articles, for example, when the resin composition of this embodiment is impregnated with glass cloth, it refers to the thickness including the glass cloth. Molded articles such as films formed from the resin composition of this embodiment can be used for exposure development to form patterns, and also for applications without exposure development. They are particularly suitable for applications without exposure development.

>>Prepreg>> An ideal prepreg is formed from a substrate (prepreg substrate) and a resin composition of this embodiment. The prepreg of this embodiment can be obtained, for example, by applying the resin composition of this embodiment to the substrate (e.g., impregnation or coating) and then semi-curing it by heating (e.g., drying at 120–220°C for 2–15 minutes). In this case, the amount of resin composition adhering to the substrate, that is, the amount of resin composition (including fillers) relative to the total amount of the semi-cured prepreg, should preferably be in the range of 20–99% by mass.

Regarding the substrate, there are no particular limitations as long as it is used in various printed circuit board materials. Examples of substrate materials include: glass fibers (e.g., E-glass, D-glass, L-glass, S-glass, T-glass, Q-glass, UN-glass, NE-glass, spherical glass, etc.), inorganic fibers other than glass (e.g., quartz), and organic fibers (e.g., polyimide, polyamide, polyester, liquid crystal polyester, etc.). The form of the substrate is not particularly limited, and examples include: woven fabrics, non-woven fabrics, rovings, plied felt, surface felt, etc., all composed of layered fibers. Substrates composed of long fibers, such as glass cloth, are particularly suitable. Here, long fibers refer to, for example, fibers with an average length of 6 mm or more. One type of substrate can be used alone, or two or more can be used in combination. Among these substrates, considering dimensional stability, fabrics treated with super-opening and pore-clogging processes are preferred; considering moisture absorption and heat resistance, glass fabrics treated with epoxy silane, amino silane, or similar surface treatments using silane coupling agents are preferred; and considering electrical properties, low-dielectric glass cloths composed of glass fibers exhibiting low dielectric constant and low dielectric loss tangent, such as L-glass, NE-glass, and Q-glass, are preferred. The thickness of the substrate is not particularly limited, and for example, it can be approximately 0.01 to 0.19 mm.

>>Metal-Clad Laminate>> An ideal embodiment of the metal-clad laminate includes: at least one layer formed from the prepreg of this embodiment, and metal foil disposed on one or both sides of the aforementioned layer formed from the prepreg. The metal-clad laminate of this embodiment can be manufactured, for example, by using at least one (preferably two or more overlapping) prepreg of this embodiment, with metal foil disposed on one or both sides and then laminated. More specifically, it can be manufactured by disposing of copper, aluminum, or other metal foils on one or both sides of the prepreg and then laminating them. The number of prepreg sheets is preferably 1 to 10, more preferably 2 to 10, and even more preferably 2 to 7. There are no particular limitations on the type of metal foil used as a material for printed circuit boards, such as rolled copper foil and electrolytic copper foil. The thickness of the copper foil is not particularly limited and can range from approximately 1.5 to 70 μm. Forming methods include those commonly used when forming printed circuit boards using laminates and multilayer boards. More specifically, methods using multi-stage presses, multi-stage vacuum presses, continuous forming machines, and high-pressure autoclave forming machines, with temperatures of approximately 180–350°C, heating times of approximately 100–300 minutes, and surface pressures of approximately 20–100 kg/ ^cm², are examples of lamination forming methods. Alternatively, a multilayer board can be manufactured by combining and laminating the prepreg of this embodiment with a separately manufactured inner layer wiring board (also known as an inner layer circuit board). Regarding the manufacturing method of the multilayer board, for example, copper foil of approximately 35μm can be disposed on both sides of a prepreg of this embodiment, and after lamination using the above-described forming method, an inner layer circuit is formed. This circuit is then blackened to form an inner layer circuit board. Subsequently, one inner layer circuit board and one prepreg of this embodiment are alternately disposed, and copper foil is further disposed on the outermost layer. Under the aforementioned conditions, it is preferable to perform the lamination under vacuum to manufacture the multilayer board. The metal foil laminate of this embodiment can be ideally used as a printed wiring board.

>>Printed Wiring Board>> An ideal embodiment of a printed wiring board includes an insulating layer and a conductor layer disposed on the surface of the insulating layer. The insulating layer comprises at least one of a layer formed of a resin composition of this embodiment and a layer formed of a prepreg of the above embodiment. Such a printed wiring board can be manufactured by conventional methods, and the manufacturing method is not particularly limited. An example of a method for manufacturing a printed wiring board is shown below. First, a metal-clad laminate, such as the copper-clad laminate mentioned above, is prepared. Then, the surface of the metal-clad laminate is etched to form an inner layer circuit, thus fabricating an inner layer substrate. As needed, a surface treatment to improve adhesive strength is applied to the inner layer circuit surface of the inner layer substrate. Then, the required number of the aforementioned prepreg sheets are overlapped on the inner layer circuit surface, and an outer layer metal foil is further overlapped on its outer side. The layers are then heated, pressed, and formed into a single unit. In this way, a multilayer laminate is manufactured in which a substrate and an insulating layer composed of a cured thermosetting resin are formed between the inner layer circuit and the outer layer circuit metal foil. Then, through-hole and via-hole machining is performed on the multi-layer laminate. A plated metal film is then formed on the wall of these holes to allow the metal foils for the inner and outer layer circuits to conduct electricity. The metal foils for the outer layer circuits are then further etched to form the outer layer circuitry, thereby creating a printed circuit board.

The printed wiring board obtained by the above-described manufacturing example has an insulating layer and a conductor layer formed on the surface of the insulating layer, and the insulating layer contains the resin composition of the present embodiment. That is, the prepreg of the present embodiment (e.g., a prepreg formed from a substrate and a resin composition of the present embodiment impregnated or coated on the substrate), and the resin composition layer of the metal foil laminate of the present embodiment are the insulating layers of the present embodiment.

>>Resin Composite Sheet>> An ideal embodiment of the resin composite sheet includes a support and a layer formed of the resin composition of this embodiment disposed on the surface of the support. The resin composite sheet can be used as a build-up film or dry film solder resist. The manufacturing method of the resin composite sheet is not particularly limited; for example, a method can be listed whereby a solution obtained by dissolving the resin composition of this embodiment in a solvent is applied to a support and then dried to obtain the resin composite sheet.

Examples of supports used here include: polyethylene film, polypropylene film, polycarbonate film, polyethylene terephthalate film, ethylene tetrafluoroethylene copolymer film, and release films obtained by coating the surface of such films with a release agent, organic film substrates such as polyimide film; conductor foils such as copper foil and aluminum foil, glass plates, SUS plates, FRP and other plate-shaped materials, without particular limitation.

Regarding coating methods, examples include applying a solution obtained by dissolving the resin composition in a solvent onto a support using a coating stick, a die-casting machine, a scraper coating machine, or a battering machine. Furthermore, after drying, the support can be peeled off or etched from the resin composite sheet formed by layering the support and the resin composition, thereby producing a single-layer sheet. Additionally, by dissolving the resin composition of the present embodiment in a solvent into a mold with a sheet-like mold groove, and then drying it to form a sheet, a single-layer sheet without a support can also be obtained.

When manufacturing the resin composite sheet of this embodiment, there are no particular limitations on the drying conditions when removing the solvent. However, considering that solvent residue may easily remain in the resin composition at low temperatures and that the resin composition may harden at high temperatures, it is advisable to perform the drying process at a temperature of 20°C to 200°C for 1 to 90 minutes. Furthermore, the resin composition in the resin composite sheet can be used in an uncured state after the solvent has been dried, or it can be used in a semi-cured (B-stage) state as needed. Furthermore, the thickness of the resin layer in the resin composite sheet of this embodiment can be adjusted by the solution concentration and coating thickness of the resin composition of this embodiment, and is not particularly limited. Generally speaking, considering the possibility of solvent residue during drying if the coating thickness is too thick, it is preferable to have a thickness of 0.1–500 μm. [Example]

The following examples further illustrate the present invention. The materials, quantities, proportions, processing methods, and processing sequences shown in the following examples can be appropriately modified, as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. In these examples, unless otherwise specified, the measurements are performed at 23°C.

Example 1: 75 parts by mass of the following synthesized multifunctional vinylbenzene polymer (ap), 25 parts by mass of a biphenyl aralkyl maleimide (manufactured by Nippon Kayaku Co., Ltd., MIR-3000 (trade name)) represented by formula (1), and 0.5 parts by mass of an imidazole catalyst (manufactured by Shikoku Kasei Co., Ltd., 2E4MZ (trade name)) were dissolved and mixed in methyl ethyl ketone to obtain a varnish.

(Synthesis of a Multifunctional Vinylbenzene Polymer (AP)) 2.25 mol (292.9 g) of divinylbenzene, 1.32 mol (172.0 g) of ethylvinylbenzene, 11.43 mol (1190.3 g) of styrene, and 15.0 mol (1532.0 g) of n-propyl acetate were added to a reactor. 600 mmol of a boron trifluoride diethyl ether complex was added at 70°C, and the reaction was allowed to proceed for 4 hours. After stopping the polymerization with a sodium bicarbonate aqueous solution, the oil layer was washed three times with pure water. The polymer was then devolatileized under reduced pressure at 60°C to recover the multifunctional vinylbenzene polymer (AP). The obtained multifunctional vinylbenzene polymer (AP) was weighed, confirming a yield of 860.8 g.

The obtained multifunctional vinylbenzene polymer (ap) has a Mn of 2060, a Mw of 30700, and a Mw/Mn ratio of 14.9. Resonance lines originating from each monomer unit were observed in the multifunctional vinylbenzene polymer (ap) by performing ^13C -NMR and ^1H -NMR analyses. Based on the NMR and GC analysis results, the proportions of the constituent units of the multifunctional vinylbenzene polymer (ap) were calculated as follows: Constituent units from divinylbenzene: 20.9 mol% (24.3 mass%); Constituent units from ethylvinylbenzene: 9.1 mol% (10.7 mass%); Constituent units from styrene: 70.0 mol% (65.0 mass%); Constituent units with residual vinyl groups from divinylbenzene: 16.7 mol% (18.5 mass%).

>>Preparation of a test piece of a hardened board with a thickness of 1.6mm>> The solvent was evaporated from the obtained varnish to obtain a mixed resin powder. The mixed resin powder was filled into a mold with a side thickness of 100mm and a thickness of 1.6mm. 12μm copper foil (3EC-M3-VLP, manufactured by Mitsui Metals Industry Co., Ltd.) was placed on both sides. Vacuum pressing was carried out for 120 minutes under the conditions of pressure of 30kg/ ^cm2 and temperature of 220°C to obtain a hardened board with a side thickness of 100mm and a thickness of 1.6mm.

The obtained 1.6mm thick hardened board was evaluated for physical properties (dielectric properties (Dk, Df), peel strength, glass transition temperature, coefficient of thermal expansion (CTE)) using the methods described below.

Example 2 The amount of the synthesized polyfunctional vinylbenzene polymer (ap) was changed to 50 parts by mass, and the amount of biphenyl aralkyl maleimide (MIR-3000) was changed to 50 parts by mass. Otherwise, the process was carried out in the same manner as in Example 1 to obtain a varnish. A 1.6 mm thick hardened sheet was obtained from this varnish in the same manner as in Example 1. The physical properties of the obtained 1.6 mm thick hardened sheet were evaluated according to the method described later.

Example 3 The amount of the synthesized polyfunctional vinylbenzene polymer (ap) was changed to 25 parts by mass, and the amount of biphenyl aralkyl maleimide (MIR-3000) was changed to 75 parts by mass. Otherwise, the process was carried out in the same manner as in Example 1 to obtain a varnish. A 1.6 mm thick hardened sheet was obtained from the obtained varnish in the same manner as in Example 1. The physical properties of the obtained 1.6 mm thick hardened sheet were evaluated according to the method described later.

Example 4 The amount of the synthesized polyfunctional vinylbenzene polymer (ap) was changed to 50 parts by mass. In addition to 25 parts by mass of biphenyl aralkyl maleimide (MIR-3000), 25 parts by mass of phenyl ether maleimide (manufactured by K.I Chemical, BMI-80 (trade name)) represented by formula (3) was added. Otherwise, the process was carried out in the same manner as in Example 1 to obtain a varnish. A 1.6 mm thick hardened sheet was obtained from the obtained varnish in the same manner as in Example 1. The physical properties of the obtained 1.6 mm thick hardened sheet were evaluated according to the method described later.

Example 5 The amount of the synthesized polyfunctional vinylbenzene polymer (ap) was changed to 50 parts by mass, and 50 parts by mass of BisM-type maleimide (manufactured by K.I Chemical Co., Ltd., BMI-BisM (trade name)) represented by formula (4) was used instead of 25 parts by mass of biphenyl aralkyl-type maleimide (MIR-3000). Otherwise, the process was the same as in Example 1 to obtain a varnish. A 1.6 mm thick hardened sheet was obtained from the obtained varnish in the same manner as in Example 1. The physical properties of the obtained 1.6 mm thick hardened sheet were evaluated according to the method described later.

Example 6 The amount of the synthesized polyfunctional vinylbenzene polymer (ap) was changed to 50 parts by mass, and 50 parts by mass of a phenyl-type maleimide (manufactured by K.I. Chemical Co., BMI-70 (trade name) equivalent to the compound of formula (2)) was used to replace 25 parts by mass of the biphenyl aralkyl-type maleimide (MIR-3000). Otherwise, the process was the same as in Example 1 to obtain a varnish. A 1.6 mm thick hardened sheet was obtained from the varnish in the same manner as in Example 1. The physical properties of the obtained 1.6 mm thick hardened sheet were evaluated according to the method described later.

>Reference Example 1> Without using biphenyl aryl maleimide (MIR-3000) and imidazole catalyst (2E4MZ), the process was carried out in the same manner as in Example 1 to obtain a varnish. A 1.6 mm thick hardened sheet was obtained from the obtained varnish in the same manner as in Example 1. The physical properties of the obtained 1.6 mm thick hardened sheet were evaluated according to the method described later.

>Reference Example 2> The polyfunctional vinylbenzene polymer (ap) synthesized above was not used, and the biphenyl aralkyl maleimide (MIR-3000) was replaced with 100 parts by weight. Otherwise, the process was carried out in the same manner as in Example 1 to obtain a varnish. A 1.6 mm thick hardened sheet was obtained from the obtained varnish in the same manner as in Example 1. The physical properties of the obtained 1.6 mm thick hardened sheet were evaluated according to the method described later.

>Reference Example 3> Instead of using the polyfunctional vinylbenzene polymer (ap) synthesized above, 100 parts by weight of BisM-type maleimide (manufactured by K.I. Chemical Co., Ltd., BMI-BisM (trade name)) were used to replace 25 parts by weight of biphenyl aralkyl-type maleimide (MIR-3000). Otherwise, the process was carried out in the same manner as in Example 1 to obtain a varnish. A 1.6 mm thick hardened sheet was obtained from the obtained varnish in the same manner as in Example 1. The physical properties of the obtained 1.6 mm thick hardened sheet were evaluated according to the method described later.

>Reference Example 4> The amount of the synthesized polyfunctional vinylbenzene polymer (ap) was changed to 50 parts by mass, and 50 parts by mass of a phenolic varnish-type maleimide (manufactured by Yamato Chemical Co., Ltd., BMI-2300 (trade name)) was used to replace 25 parts by mass of the biphenyl aralkyl maleimide (MIR-3000). Otherwise, the process was carried out in the same manner as in Example 1 to obtain a varnish. A 1.6 mm thick hardened sheet was obtained from the obtained varnish in the same manner as in Example 1. The physical properties of the obtained 1.6 mm thick hardened sheet were evaluated according to the method described later.

>Reference Example 5> The amount of the synthesized polyfunctional vinylbenzene polymer (ap) was changed to 50 parts by mass, and 50 parts by mass of end-modified polyphenylene ether (manufactured by Mitsubishi Gas Chemical Co., Ltd., OPE-2St 1200 (trade name)) was used to replace 25 parts by mass of biphenyl aralkyl maleimide (MIR-3000). Otherwise, the process was carried out in the same manner as in Example 1 to obtain a varnish. A 1.6 mm thick hardened sheet was obtained from the obtained varnish in the same manner as in Example 1. The physical properties of the obtained 1.6 mm thick hardened sheet were evaluated according to the method described later.

>Reference Example 6> The amount of the synthesized polyfunctional vinylbenzene polymer (ap) was changed to 50 parts by mass. 36.5 parts by mass of a biphenyl aralkyl type epoxide (manufactured by Nippon Kayaku Co., Ltd., NC3000FH (trade name)) and 13.5 parts by mass of cresol phenolic varnish (manufactured by DIC Co., Ltd., KA-1163 (trade name)) were used instead of 25 parts by mass of the biphenyl aralkyl type maleimide (MIR-3000). The amount of imidazole catalyst was changed to 0.2 parts by mass. Otherwise, the process was carried out in the same manner as in Example 1 to obtain a varnish. A 1.6 mm thick hardened sheet was obtained from the obtained varnish in the same manner as in Example 1. The physical properties of the obtained 1.6 mm thick hardened sheet were evaluated according to the method described later.

>Dielectric Properties (Dk and Df)> The relative permittivity (Dk) and dielectric loss tangent (Df) at 10 GHz were measured on test pieces obtained by etching away copper foil from a 1.6 mm thick hardened board. The measurement temperature was 23 °C. The Agilent 8722ES perturbed cavity resonator was used. Furthermore, in Table 1 below, Dk (relative permittivity) below 2.5 is designated as "S", above 2.5 but below 2.6 as "A", above 2.6 but below 2.7 as "B", and above 2.7 as "C". Regarding Df (dielectric loss tangent), values below 0.0015 are designated as "S", values exceeding 0.0015 but below 0.0020 are designated as "A", values exceeding 0.0020 but below 0.0040 are designated as "B", and values exceeding 0.0040 are designated as "C".

>Long-Term Thermal Dielectric Properties> Test pieces obtained by etching away the copper foil from a 1.6mm thick hardened board were placed at 125°C in air for 500 hours. Using these test pieces, the Dk and Df values at 10GHz after thermal degradation were measured using a perturbation-based void resonator. The changes in Dk and Df relative to the values before thermal degradation were calculated. The perturbation-based void resonator used was the Agilent 8722ES. Furthermore, in Table 1 below, for the change in Dk after thermal degradation relative to the value before thermal degradation, values below 0.02 are denoted as "S", values exceeding 0.02 but below 0.04 are denoted as "A", values exceeding 0.04 but below 0.06 are denoted as "B", and values exceeding 0.06 are denoted as "C". Furthermore, regarding the change in Df after thermal degradation relative to Df before thermal degradation, values below 0.001 are denoted as "S", values exceeding 0.001 but below 0.002 are denoted as "A", values exceeding 0.002 but below 0.003 are denoted as "B", and values exceeding 0.003 are denoted as "C".

>Peel Strength> Using the hardened board obtained as described above, the peel strength (adhesive force) of the copper foil was measured twice according to JIS C6481, section 5.7, "Peel Strength," and the average value was calculated. Furthermore, in Table 1 below, regarding peel strength, 0.8 kN/m or higher is designated as "S," less than 0.8 kN/m but more than 0.6 kN/m is designated as "A," less than 0.6 kN/m but more than 0.5 kN/m is designated as "B," and less than 0.5 kN/m is designated as "C."

>Glass Transition Temperature> Regarding the glass transition temperature (Tg), for test pieces obtained by etching away copper foil from a 1.6 mm thick hardened plate, the Tg was determined using a dynamic viscoelastic analysis apparatus and the DMA (Dynamic Mechanical Analysis) bending method, according to JIS C6481 5.17.2. The glass transition temperature was estimated from the obtained tanδ graph. The dynamic viscoelastic analysis apparatus used was a device manufactured by TA Instruments. Furthermore, in Table 1, for glass transition temperatures, those above 300°C are indicated as "S", those below 300°C but above 220°C are indicated as "A", those below 220°C but above 200°C are indicated as "B", and those below 200°C are indicated as "C".

>Coefficient of Linear Thermal Expansion (CTE)> (CTE: Coefficient of linear Thermal Expansion) For test pieces obtained by etching away copper foil from a 1.6 mm thick hardened board, the coefficient of thermal expansion of the hardened board was determined using the TMA (Thermo-Mechanical Analysis) method specified in JIS C 6481 5.19. Specifically, after etching away the copper foil on both sides of the obtained hardened board, the coefficient of linear thermal expansion (ppm/℃) was measured using a thermo-mechanical analysis apparatus (manufactured by TA Instruments) at a temperature increase of 10℃ per minute from 40℃ to 340℃. ppm is a volume ratio. Other details are as described in JIS C 6481 5.19.

[Table 1] (In the table) Dk: Relative permittivity at 10 GHz; Df: Dielectric loss tangent at 10 GHz; Peel strength: Result of copper foil peel test; Glass transition temperature: Glass transition temperature evaluated by tanδ measured using the DMA method; CTE: Coefficient of thermal expansion measured using the TMA method.

As shown in Table 1 above, the resin composition of this embodiment, which combines a multifunctional vinyl aromatic polymer (A) (a multifunctional vinylbenzene polymer (ap)) and a maleimide compound (B) with a specific structure (compounds represented by formulas (1) to (4)), produces a film with excellent dielectric properties (low dielectric constant, low dielectric loss tangent), high peel strength, and excellent heat resistance (sufficiently high glass transition temperature). Furthermore, the dielectric properties (change in dielectric properties) after long-term heating are also excellent. In contrast, Reference Example 1 does not contain the specific maleimide compound (B) and only uses the multifunctional vinyl aromatic polymer (A). Its dielectric properties and peel strength after long-term heating are poor, and its glass transition temperature is also low. Examples 2 and 3 are examples without the polyfunctional vinyl aromatic polymer (A). In Example 2, the relative dielectric constant (Dk) is poor. In Example 3, the peel strength is poor, and the glass transition temperature is low. Example 4 uses the polyfunctional vinyl aromatic polymer (A) and a compound containing maleimide groups. However, the compound containing maleimide groups is a phenolic varnish-type maleimide (BMI-2300), which is not included in the compounds represented by formulas (1) to (4). In Example 4, the glass transition temperature is low. Example 5 is a combination of the polyfunctional vinyl aromatic polymer (A) and a terminally modified polyphenylene ether resin, but the resin composition results in poor dielectric properties after prolonged heating. Reference Example 6 uses a biphenyl alkyl epoxide and a cresol phenolic varnish resin combined with a multifunctional vinyl aromatic polymer (A). This resin composition has a low density (Df), low density (Dk) after long-term heating, poor peel strength, and low glass transition temperature, resulting in undesirable outcomes. Furthermore, it can be seen that by changing the amount and type of the multifunctional vinyl aromatic polymer (A) and the maleimide compound (B) in the embodiments, the dielectric constant can be set to excellent (Example 1), and the dielectric properties, peel strength, and heat resistance (high glass transition temperature) after long-term heating can be set to excellent (Examples 2-5, especially Examples 2 and 3).

Example 7: 50 parts by weight of the above-synthesized multifunctional vinylbenzene polymer (ap), 50 parts by weight of biphenyl aralkyl maleimide (manufactured by Nippon Kayaku Co., Ltd., MIR-3000 (trade name)), 0.5 parts by weight of imidazole catalyst (manufactured by Shikoku Kasei Co., Ltd., 2E4MZ (trade name)), and 50 parts by weight of slurry silica (spherical silica) (manufactured by Admatechs Co., Ltd., SC2050-MNU (trade name)) were dissolved and mixed in methyl ethyl ketone to obtain a varnish.

The obtained varnish was impregnated and coated onto a 0.069 mm thick low-dielectric glass cloth. The cloth was then dried using a pressure-resistant, explosion-proof steam dryer (manufactured by Takasugi Manufacturing Co., Ltd.) at 150°C for 3 minutes to obtain a prepreg with a resin composition adhesion to the substrate of 60% by mass. A 12 μm copper foil (3EC-M3-VLP, manufactured by Mitsui Metals Mining Co., Ltd.) was placed on both sides of the prepreg, and vacuum-pressed at a pressure of 30 kg/ ^cm² and a temperature of 220°C for 120 minutes to obtain a 0.1 mm thick copper-clad laminate. Furthermore, with four prepregs stacked on top of each other, 12μm copper foils were placed on both sides, and vacuum pressing was performed for 120 minutes under a pressure of 30kg/ ^cm² and a temperature of 220°C to obtain a copper-clad laminate with a thickness of 0.4mm.

For the obtained copper-clad laminates with thicknesses of 0.1 mm and 0.4 mm, physical properties (dielectric properties (Dk, Df), dielectric properties after long-term heating, peel strength, and glass transition temperature) were evaluated using the methods described above. However, the hardened boards were copper-clad laminates with thicknesses changed from 1.6 mm to 0.1 mm and 0.4 mm. For the copper-clad laminates, the copper foil was removed by etching during the determination of dielectric properties and glass transition temperature. Regarding the coefficient of thermal expansion (CTE), the CTE in the warp direction of the glass cloth was measured. Furthermore, the moisture absorption and heat resistance (bulging) described later was measured.

>Ref. Example 7> The multifunctional vinylbenzene polymer (ap) synthesized above was changed to 100 parts by weight, and the biphenyl aralkyl maleimide (MIR-3000) and imidazole catalyst (2E4MZ) were not used. Except for this, a varnish was prepared in the same manner as in Example 7 to obtain a copper-clad laminate. The evaluation results for various aspects of the obtained copper-clad laminate are shown in Table 2.

>Ref. Example 8> The polyfunctional vinylbenzene polymer (ap) synthesized above was not used, and the biphenyl aralkyl maleimide (MIR-3000) was replaced with 100 parts by weight. Otherwise, a varnish was prepared in the same manner as in Example 7 to obtain a copper-clad laminate. The evaluation results for various aspects of the obtained copper-clad laminate are shown in Table 2.

Moisture Absorption and Heat Resistance> Cut a copper-clad laminate into pieces (50mm × 50mm × 0.4mm insulation thickness). Etch away all copper foil except for half of one side to obtain test pieces. Treat the obtained test pieces according to JIS C648 using a pressure cooker (Hiraya Manufacturing Co., Ltd., PC-3 type) at 121°C and 2 atmospheres for 5 hours, then immerse them in solder at 260°C for 30 seconds. Visually observe for any bulging after immersion and evaluate the moisture absorption and heat resistance according to the following evaluation criteria. >>Bulging Presence>> A: No abnormality B: Bulging occurs

[Table 2] Evaluation Items unit Implementation Example 7 See Example 7 See Example 8 Dk - 3.16 3.08 3.54 Df - 0.0023 0.0018 0.0024 Changes in Dk after long-term heating - 0.02 0.04 0.01 Change in Df after long-term heating - 0.0007 0.0015 0.0002 Peel strength kN/m 0.56 0.27 0.45 Glass transition temperature (DMA), tanδ ℃ 317 218 292 Moisture absorption and heat resistance - A B A CTE TMA ppm/℃ 12 15 13 (In the table) Dk: Relative permittivity at 10 GHz; Df: Dielectric loss tangent at 10 GHz; Peel strength: Result of copper foil peel test; Glass transition temperature: Glass transition temperature evaluated by tanδ measured using the DMA method; CTE: Coefficient of thermal expansion measured using the TMA method.

The results in Table 2 above confirm that when a filler (spherical silica) is used to fabricate a copper-clad laminate with the resin composition of this embodiment, it exhibits excellent durability against extremely high heat (high glass transition temperature). Furthermore, the moisture absorption and heat resistance are also good. In contrast, in Reference Example 7, which does not contain a specific maleimide compound (B), the moisture absorption and heat resistance are poor, resulting in bulging. Furthermore, in Reference Example 8, which does not contain a polyfunctional vinyl aromatic polymer (A), Dk is high.

Claims (11)

A resin composition comprising a polyfunctional vinyl aromatic polymer (A) and a maleimide compound (B), comprising at least one compound represented by any one of the following formulas (1) to (4) as the maleimide compound (B), and not comprising an allyl cyclophosphamide compound, wherein the polyfunctional vinyl aromatic polymer (A) is a thermosetting resin, and the total content of the polyfunctional vinyl aromatic polymer (A) and the maleimide compound (B) in the resin composition is 80% by mass or more. In formula (1), ^R1 , ^R2 , ^R3 and ^R4 each independently represent a hydrogen atom, an alkyl or phenyl group having 1 to 8 carbon atoms, and n1 represents a number of 1 or more and less than 10; In formula (2), ^R6 each independently represents a methyl or ethyl group, and ^R7 each independently represents a hydrogen atom or a methyl group; In formula (3), ^R8 independently represents a hydrogen atom, a methyl atom, or an ethyl atom; In formula (4), ^R9 each independently represents a hydrogen atom, a methyl atom, or an ethyl atom. The resin composition of claim 1, wherein the multifunctional vinyl aromatic polymer (A) is a polymer having constituent units represented by formula (V); In formula (V), Ar represents an aromatic hydrocarbon linker; * represents the bonding position. For example, in the resin composition of claim 1 or 2, the content of the maleimide compound (B) is 5 to 95 parts by mass relative to 100 parts by mass of the total amount of resin components in the resin composition. For example, in the resin composition of claim 1 or 2, the content of the polyfunctional vinyl aromatic polymer (A) is 5 to 95 parts by mass relative to 100 parts by mass of the total amount of resin components in the resin composition. The resin composition of claim 1 or 2 further contains filler (C). For example, in the resin composition of claim 5, the content of the filler (C) is 10 to 500 parts by mass relative to 100 parts by mass of the total amount of resin components in the resin composition. The resin composition of claim 1 or 2, wherein the multifunctional vinyl aromatic polymer (A) has a constituent unit derived from an aromatic compound having two or more vinyl groups within the molecule. A prepreg formed of a substrate and a resin composition as claimed in any of claims 1 to 7. A metal foil laminate comprising: at least one layer formed of a prepreg as claimed in claim 8; and a metal foil disposed on one or both sides of the layer formed of the prepreg. A resin composite sheet comprising: a support; and a layer disposed on the surface of the support, formed of a resin composition as described in any one of claims 1 to 7. A printed wiring board includes: an insulating layer; and a conductor layer disposed on the surface of the insulating layer; the insulating layer includes at least one of a layer formed of a resin composition as claimed in any one of claims 1 to 7 and a layer formed of a prepreg as claimed in claim 8.