Resin composition, prepreg, film with resin, metal foil with resin, metal-reinforced layered board, and printed circuit board

Abstract

This resin composition contains a thermosetting resin (A) and a styrene polymer (B). The styrene polymer (B) contains an acid-modified styrene polymer (B-1) and a styrene polymer (B-2) other than the acid-modified styrene polymer (B-1). The mass ratio of the acid-modified styrene polymer (B-1) and other styrene polymer (B-2) is 5:95 to 95:5.

Description

Resin compositions, prepregs, resin-coated films, resin-coated metal foils, metal-clad laminates, and wiring boards.

[0001] The present invention relates to resin compositions, prepregs, resin-coated films, resin-coated metal foils, metal-clad laminates, and wiring boards.

[0002] In recent years, with the increasing performance of electronic devices and the remarkable improvement in information and communication speeds, semiconductor package substrates used in network equipment, servers, and AI processors are becoming more high-performance and highly integrated. Furthermore, this progress is leading to larger and higher-density substrates. Therefore, there is a demand for substrates with low warpage and high mounting reliability. To achieve these, substrate materials are required to have a low coefficient of thermal expansion from the viewpoint of ensuring connection reliability such as low warpage and narrow pitch.

[0003] For example, Patent Document 1 describes a resin composition comprising a cyanate resin and / or its prepolymer, an epoxy resin, a benzoxazine resin, and an inorganic filler as essential components. The resin composition is described as having excellent heat resistance, low thermal expansion, and flame retardancy, and that the low thermal expansion properties are obtained by including the benzoxazine resin in the resin composition.

[0004] Furthermore, numerous techniques have been reported to achieve a low thermal expansion coefficient for substrate materials, for example, by incorporating maleimide compounds into the resin composition and filling it with a filler having a low thermal expansion coefficient.

[0005] Japanese Patent Publication No. 2004-182851

[0006] The present invention aims to provide a resin composition that maintains a low coefficient of thermal expansion during curing while having high storage stability. Furthermore, the present invention aims to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that can be obtained using this resin composition.

[0007] The inventors of this invention have diligently studied and researched the above problems, and as a result have arrived at the present invention.

[0008] The resin composition according to the first aspect of the present invention contains a thermosetting resin (A) and a styrenic polymer (B), the styrenic polymer (B) includes an acid-modified styrenic polymer (B-1) and another styrenic polymer (B-2) different from the acid-modified styrenic polymer (B-1), and the mass ratio of the acid-modified styrenic polymer (B-1) to the other styrenic polymer (B-2) is from 5:95 to 95:5.

[0009] The prepreg according to the second aspect of the present invention comprises the resin composition according to the first aspect of the present invention or a semi-cured product of the resin composition, and a fibrous base material.

[0010] The resin-attached film according to the third aspect of the present invention comprises a resin layer containing the resin composition according to the first aspect of the present invention or a semi-cured product of the resin composition, and a support film.

[0011] The metal foil with resin according to the fourth aspect of the present invention comprises a resin layer containing the resin composition according to the first aspect of the present invention or a semi-cured product of the resin composition, and a metal foil.

[0012] The metal-clad laminate according to the fifth aspect of the present invention comprises an insulating layer containing a cured product of the resin composition according to the first aspect of the present invention, and a metal foil.

[0013] The wiring board according to the sixth aspect of the present invention comprises an insulating layer containing a cured product of the resin composition according to the first aspect of the present invention, and a wiring.

[0014] FIG. 1 is a schematic cross-sectional view showing an example of a prepreg according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing an example of a wiring board according to an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing an example of a metal foil with resin according to an embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing an example of a resin-attached film according to an embodiment of the present invention.

[0015] From the viewpoint of ensuring low thermal expansion properties, the use of maleimide compounds or benzoxazine compounds (see Patent Document 1) as substrate materials and high filling of fillers with low coefficient of thermal expansion have been progressing. However, further improvement is required regarding the problems of low warpage of substrates and substrate uniformity.

[0016] In general, the storage stability of a resin composition varnish affects the low warpage property and uniformity of a substrate. Therefore, it is favorable if a resin composition with improved varnish stability can be obtained while achieving a low coefficient of thermal expansion for the substrate material.

[0017] As a result of intensive studies by the present inventors, it has been found that when a resin composition contains a thermosetting resin (A), an acid-modified styrene-based polymer (B-1), and another styrene-based polymer (B-2) different from the acid-modified styrene-based polymer (B-1), and the mass ratio of the acid-modified styrene-based polymer (B-1) to the other styrene-based polymer (B-2) falls within a predetermined range, the resin composition has high storage stability while maintaining a low coefficient of thermal expansion upon curing.

[0018] As described above, according to the present invention, a resin composition having high storage stability while maintaining a low coefficient of thermal expansion upon curing can be provided. Furthermore, according to the present invention, by using the resin composition, a prepreg, a resin-coated film, a metal foil with resin, a metal-clad laminate, and a wiring board having excellent performance can be provided.

[0019] In the present specification, the terms "thermosetting resin", "polymer", "crosslinking agent", "radically polymerizable compound (such as hydrocarbon compounds having an indene ring or a fluorene ring, and phenylmaleimide compounds)", and "reactive compound (such as N-alkylmaleimide compounds, epoxy compounds, allyl compounds, and polyphenylene ether compounds having a carbon-carbon unsaturated double bond)" refer to components that include both resins and polymers as polymers, and monomers (in an uncured state) that can form such resins and polymers.

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without impairing the gist of the present invention.

[0021] <Resin Composition> The resin composition according to this embodiment (hereinafter also simply referred to as "resin composition") contains a thermosetting resin (A) and a styrene polymer (B). The styrene polymer (B) includes an acid-modified styrene polymer (B-1) and another styrene polymer (B-2) different from the acid-modified styrene polymer (B-1) (hereinafter also simply referred to as "the other styrene polymer (B-2)").

[0022] Furthermore, the mass ratio of the acid-modified styrene polymer (B-1) to the other styrene polymer (B-2) satisfies the condition of 5:95 to 95:5.

[0023] The following describes in detail each component contained in the resin composition, the uses of the resin composition, and the method for preparing the resin composition.

[0024] [Thermosetting resin (A)] The thermosetting resin (A) is not particularly limited as long as it is any thermosetting resin known to those skilled in the art that can obtain the effects of a low coefficient of thermal expansion and high storage stability according to this embodiment and is commonly used in semiconductor package substrates and the like.

[0025] Specifically, it is preferable that the thermosetting resin (A) contains a radical polymerizable compound (A-1). Furthermore, it is even more preferable that the thermosetting resin (A) contains a radical polymerizable compound (A-1) and a reactive compound (A-2) different from the radical polymerizable compound (A-1) (hereinafter also simply referred to as "reactive compound (A-2)"). When the thermosetting resin (A) contains both the radical polymerizable compound (A-1) and the radical polymerizable compound (A-1), the glass transition temperature (Tg) of the cured resin composition tends to be lower. Furthermore, this can further reduce the thermal expansion coefficient of the cured resin composition at high temperatures (for example, about 200°C to 240°C). The components will be described in detail below.

[0026] (Radical polymerizable compound (A-1)) The radical polymerizable compound (A-1) is not particularly limited, but it is preferable to include at least one selected from the group consisting of hydrocarbon compounds having an indene ring and / or a fluorene ring (A-11) and phenylmaleimide compounds (A-12).

[0027] The hydrocarbon compound (A-11) having an indene ring and / or a fluorene ring is not particularly limited as long as it has an indene ring and / or a fluorene ring and functions as a crosslinking agent for thermosetting resins, and any radically polymerizable compound known to those skilled in the art can be used. Specifically, since it needs to function as a crosslinking agent for thermosetting resins, the hydrocarbon compound (A-11) having an indene ring and / or a fluorene ring preferably has a substituent having a carbon-carbon unsaturated double bond. When the resin composition contains such a hydrocarbon compound (A-11) having an indene ring and / or a fluorene ring, a low coefficient of thermal expansion during curing can be improved, and the storage stability of the varnish of the resin composition can also be improved.

[0028] Particularly preferred examples of such a hydrocarbon compound (A-11) having an indene ring and / or a fluorene ring include the crosslinking agent (A-11-1) described below.

[0029] The crosslinking agent (A-11-1) is (i) vinylbenzylindene represented by the following formula (1), [In the formula (1), R １ , R ２ and R ３ are each independently selected from a vinylbenzyl group, a hydrogen atom, a lower alkyl group, a thioalkoxy group having 1 to 5 carbon atoms, and an aryl group, and R １ , R ２ and R ３ at least one of which is a vinylbenzyl group. R ４ is selected from a hydrogen atom, a halogen atom, a lower alkyl group, an alkoxy group having 1 to 5 carbon atoms, a thioalkoxy group having 1 to 5 carbon atoms, a thioaryloxy group, and an aryl group.] (ii) vinylbenzylfluorene represented by the following formula (2), [In the formula (2), each R ５ is each independently selected from a hydrogen atom, a halogen atom, a lower alkyl group, an alkoxy group having 1 to 5 carbon atoms, a thioalkoxy group having 1 to 5 carbon atoms, and an aryl group. x is an integer of 0 to 4. R ６ and R ７Each of these is independently selected from a vinylbenzyl group, a hydrogen atom, a lower alkyl group, a thioalkoxy group having 1 to 5 carbon atoms, and an aryl group, and R ６ and R ７ (iii) Preferably, the compound or mixture is selected from (iii) a mixture thereof, which is a vinylbenzyl group, and (iii) a mixture thereof.

[0030] When a resin composition contains such a crosslinking agent (A-11-1), not only is it expected that the storage stability of the varnish will be improved, but a cured product with excellent low dielectric properties, particularly a low dielectric loss tangent, can be obtained. Furthermore, it is anticipated that the heat resistance and flame retardancy of the cured product of the resin composition will also be improved. In addition, it is anticipated that a good low coefficient of thermal expansion of the cured product can be achieved.

[0031] The vinylbenzylindene represented by the above formula (1) is R １ , R ２ and R ３ Each is independently selected from a hydrogen atom and a vinylbenzyl group, and R １ , R ２ and R ３ At least one of them is a vinylbenzyl group, R ４ Examples include compounds selected from hydrogen atoms, halogen atoms, and lower alkyl groups.

[0032] Furthermore, vinylbenzylindene represented by the above formula (1) is R １ , R ２ and R ３ Each is independently selected from a hydrogen atom and a vinylbenzyl group, R １ , R ２ and R ３ At least one of them is a vinylbenzyl group, and R ４ It may also be a compound in which the atom is a hydrogen atom.

[0033] Furthermore, the vinylbenzylindene represented by the above formula (1) is R １ and R ２ is a vinylbenzyl group, R ３ is a hydrogen atom or a vinylbenzyl group, and R ４It may also be a compound in which the atom is a hydrogen atom.

[0034] To give a more specific example, vinylbenzylindene is 1,1,3-(2-vinylbenzyl)-1H-indene, 1,1,2-(3-vinylbenzyl)-1H-indene, 1,1,2-(4-vinylbenzyl)-1H-indene, 1,1-(2-vinylbenzyl)-1H-indene, 1,1-(3-vinylbenzyl)-1H-indene, 1,1-(4-vinylbenzyl)-1H-indene, 1,3-(2-vinylbenzyl)-1H-indene, 1,3-(3-vinyl Preferably, the material contains at least one selected from benzyl)-1H-indene; 1,3-(4-vinylbenzyl)-1H-indene, 1-(2-vinylbenzyl)-1H-indene, 1-(3-vinylbenzyl)-1H-indene, 1-(4-vinylbenzyl)-1H-indene, 3-(2-vinylbenzyl)-1H-indene, 3-(3-vinylbenzyl)-1H-indene, 3-(4-vinylbenzyl)-1H-indene, and mixtures thereof.

[0035] Furthermore, the vinylbenzylindene represented by the above formula (1) is R １ , R ２ and R ３ is a vinylbenzyl group, R ４ It may also be a compound in which the atom is a hydrogen atom.

[0036] The crosslinking agent (A-11-1) may contain only one vinylbenzylindene, or it may be a mixture of multiple vinylbenzylindenes.

[0037] When the crosslinking agent (A-11-1) contains a mixture of multiple vinylbenzylindenes, it is preferable that the vinylbenzylindene mixture contains at least one of 1,1,3-(2-vinylbenzyl)-1H-indene, 1,1,2-(3-vinylbenzyl)-1H-indene, and 1,1,2-(4-vinylbenzyl)-1H-indene in an amount of 50% by weight or more, and at least one of 1,1-(2-vinylbenzyl)-1H-indene, 1,1-(3-vinylbenzyl)-1H-indene, 1,1-(4-vinylbenzyl)-1H-indene, 1,3-(2-vinylbenzyl)-1H-indene, 1,3-(3-vinylbenzyl)-1H-indene, and 1,3-(4-vinylbenzyl)-1H-indene in an amount of less than 50% by weight.

[0038] Furthermore, the vinylbenzylindene mixture may contain approximately 50% to 85% by weight of 1,1,2-(4-vinylbenzyl)-1H-indene, approximately 10% to 50% by weight of 1,1,2-(3-vinylbenzyl)-1H-indene, and 0% to 10% by weight of 1,1,3-(2-vinylbenzyl)-1H-indene. Here, "by weight" refers to the weight percentage relative to the total amount of the vinylbenzylindene mixture.

[0039] The vinylbenzylindene mixture may further contain, in less than 5% by weight, at least one of the following compounds based on the total amount of vinylbenzylindene: 1-(2-vinylbenzyl)-1H-indene, 1-(3-vinylbenzyl)-1H-indene, 1-(4-vinylbenzyl)-1H-indene, 3-(2-vinylbenzyl)-1H-indene, 3-(3-vinylbenzyl)-1H-indene, and 3-(4-vinylbenzyl)-1H-indene.

[0040] The vinylbenzylfluorene represented by the above formula (2) is as follows: ５ Each is independently selected from a hydrogen atom, a halogen atom, and a lower alkyl group, R ６ and R ７Each is independently selected from a vinylbenzyl group, a hydrogen atom, and a lower alkyl group, and R ６ and R ７ Examples of compounds in which at least one of the groups is a vinylbenzyl group include those compounds in which at least one of the groups is a vinylbenzyl group.

[0041] The vinylbenzylfluorene represented by the above formula (2) is each R ５ is a hydrogen atom, R ６ and R ７ Each of these may be a compound independently selected from a vinylbenzyl group and a hydrogen atom.

[0042] The vinylbenzylfluorene represented by the above formula (2) is each R ５ is a hydrogen atom, R ６ and R ７ The compound may be a vinylbenzyl group.

[0043] Furthermore, the vinylbenzylfluorene represented by formula (2) above is preferably selected from 9,9-bis-(o-vinylbenzyl)-9H-fluorene, 9,9-bis-(m-vinylbenzyl)-9H-fluorene, 9,9-bis-(p-vinylbenzyl)-9H-fluorene, and mixtures thereof.

[0044] The crosslinking agent (A-11-1) may contain 0% to 100% by weight of vinylbenzylindene represented by formula (1) and 100% to 0% by weight of vinylbenzylfluorene represented by formula (2) based on the total amount of crosslinking agent (A-11-1). Alternatively, the crosslinking agent (A-11-1) may contain 10% to 90% by weight of vinylbenzylindene represented by formula (1) and 90% to 10% by weight of vinylbenzylfluorene represented by formula (2) based on the total amount of crosslinking agent (A-11-1).

[0045] Furthermore, the crosslinking agent (A-11-1) may contain, with respect to the total amount of the crosslinking agent (A-11-1), 20% to 80% by weight, 30% to 70% by weight, or 40% to 60% by weight of vinylbenzylindene represented by formula (1), and 80% to 20% by weight, 70% to 30% by weight, or 60% to 40% by weight of vinylbenzylfluorene represented by formula (2).

[0046] In one specific example, the crosslinking agent (A-11-1) is: vinylbenzylindene represented by formula (1) above, in an amount of at least about 50% by weight, at least about 60% by weight, at least about 70% by weight, or at least about 80% by weight of vinylbenzylindene, consisting of at least one vinylbenzylindene from among 1,1,3-(2-vinylbenzyl)-1H-indene, 1,1,2-(3-vinylbenzyl)-1H-indene and 1,1,2-(4-vinylbenzyl)-1H-indene; and less than about 50% by weight, less than about 40% by weight, less than about 30% by weight, or less than about 20% by weight of 1,1-(2-vinylbenzyl)-1H-indene, 1,1-(3-vinylbenzyl)- A vinylbenzylindene comprising at least one vinylbenzylindene from among 1H-indene, 1,3-(2-vinylbenzyl)-1H-indene, 1,3-(3-vinylbenzyl)-1H-indene, and 1,3-(4-vinylbenzyl)-1H-indene; and at least one vinylbenzylindene from among 1-(2-vinylbenzyl)-1H-indene, 1-(3-vinylbenzyl)-1H-indene, 1-(4-vinylbenzyl)-1H-indene, 3-(2-vinylbenzyl)-1H-indene, 3-(3-vinylbenzyl)-1H-indene, and 3-(4-vinylbenzyl)-1H-indene in amounts less than 5% by weight, less than 3% by weight, less than 1% by weight, or 0% by weight; The vinylbenzylfluorene represented by formula (2) above may include at least one vinylbenzylfluorene selected from 9,9-bis-(2-vinylbenzyl)-9H-fluorene, 9,9-bis-(3-vinylbenzyl)-9H-fluorene, 9,9-bis-(4-vinylbenzyl)-9H-fluorene, and mixtures thereof.

[0047] The phenylmaleimide compound (A-12) is not limited to any compound having a phenylmaleimide group, and any radically polymerizable phenylmaleimide compound known to those skilled in the art can be used.

[0048] It is preferable that such phenylmaleimide compounds (A-12) include compounds having at least one structure in the molecule, which is an indan structure and an arylene structure bonded in a meta position.

[0049] Furthermore, it is more preferable that the phenylmaleimide compound (A-12) described above includes at least one selected from the group consisting of a phenylmaleimide compound having an indan structure in its molecule, a phenylmaleimide compound having an arylene structure bonded in a meta position, and a phenylmaleimide compound having an indan structure and an arylene structure bonded in a meta position in its molecule.

[0050] Phenylmaleimide compounds having an indane structure in their molecule also have a phenylmaleimide group in their molecule. An example of an indane structure is the indane structure represented by formula (3) below. Therefore, an example of such a phenylmaleimide compound is the phenylmaleimide compound represented by formula (4) below.

[0051]

[0052] In formula (3) above, each Rb is independent. That is, each Rb may be the same group or different groups. For example, when r is 2 or 3, the two or three Rb groups bonded to the same benzene ring may be the same group or different groups. Rb represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group (alkoxy group) having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group (thiol group). r represents 0 to 3.

[0053]

[0054] In formula (4) above, each Ra is independent. That is, each Ra may be the same group or a different group. For example, when q is 2 to 4, the 2 to 4 Ra groups bonded to the same benzene ring may be the same group or a different group. Ra represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. Rb is the same as Rb in formula (4) above, and each independently represents a C1-C10 alkyl group, a C1-C10 alkyloxy group, a C1-C10 alkylthio group, a C6-C10 aryl group, a C6-C10 aryloxy group, a C6-C10 arylthio group, a C3-C10 cycloalkyl group, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. q represents 0-4. r represents 0-3. n represents 0.95-10. r is the average degree of substitution of Rb, and a smaller value is preferable, specifically 0.

[0055] The groups represented by Ra and Rb specifically include the following groups:

[0056] The alkyl group having 1 to 10 carbon atoms is not particularly limited and includes, for example, a methyl group, an ethyl group, a propyl group, a hexyl group, a decyl group, etc. The alkyloxy group having 1 to 10 carbon atoms is not particularly limited and includes, for example, a methyloxy group, an ethyloxy group, a propyloxy group, a hexyloxy group, a decyloxy group, etc. The alkylthio group having 1 to 10 carbon atoms is not particularly limited and includes, for example, a methylthio group, an ethylthio group, a propylthio group, a hexylthio group, a decylthio group, etc. The aryl group having 6 to 10 carbon atoms is not particularly limited and includes, for example, a phenyl group, a naphthyl group, etc. The aryloxy group having 6 to 10 carbon atoms is not particularly limited and includes, for example, a phenyloxy group, a naphthyloxy group, etc. The arylthio group having 6 to 10 carbon atoms is not particularly limited and includes, for example, a phenylthio group, a naphthylthio group, etc. The cycloalkyl group having 3 to 10 carbon atoms is not particularly limited and includes, for example, a cyclopropyl group, a cyclobutyl group, a cyclohexyl group, a cyclooctyl group, etc. The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.

[0057] q is the average degree of substitution of Ra, and is preferably 2 to 3, and more preferably 2.

[0058] n is the average value of the number of repetitions, and is between 0.95 and 10, preferably between 0.98 and 8, more preferably between 1 and 7, and even more preferably between 1.1 and 6.

[0059] Phenylmaleimide compounds having an arylene structure bonded in a meta position have an arylene structure bonded in a meta position, and also have a phenylmaleimide group in the molecule. Examples of arylene structures include arylene structures in which a structure containing a phenylmaleimide group is bonded in a meta position (arylene structures in which a structure containing a maleimide group is substituted in a meta position). Examples of arylene structures include m-arylene groups such as m-phenylene groups and m-naphthylene groups. Specifically, an example of an arylene structure in the phenylmaleimide compound is an arylene group bonded in a meta position, such as the group represented by formula (5) below.

[0060]

[0061] Examples of such phenylmaleimide compounds include the phenylmaleimide compound represented by formula (6) below, and more specifically, the phenylmaleimide compound represented by formula (7) below.

[0062]

[0063] In the above formula (6), Ar represents an arylene group that is oriented and bonded at the meta position. Ａ , R Ｂ , R Ｃ And, R Ｄ They are independent of each other. That is, R Ａ , R Ｂ , R Ｃ and R Ｄ These may be the same group or different groups. Also, R Ａ , R Ｂ , R Ｃ and R Ｄ R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and is preferably a hydrogen atom. Ｅ and R Ｆ They are independent of each other. That is, R Ｅ and R Ｆ This may be the same group or different groups. Also, RＥ and R Ｆ represents an aliphatic hydrocarbon group. s is such that 1 < s < 5.

[0064] The arylene group is not particularly limited as long as it is an arylene group that is oriented and bonded to the meta position. Examples include m-phenylene groups, m-naphthylene groups, and other m-arylene groups. More specifically, examples include the group represented by formula (5) above.

[0065] Examples of alkyl groups having 1 to 5 carbon atoms include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl, and neopentyl groups.

[0066] The aliphatic hydrocarbon group is a divalent group and may be acyclic or cyclic. Examples of aliphatic hydrocarbon groups include alkylene groups, and more specifically, methylene groups, methylmethylene groups, and dimethylmethylene groups. Among these, dimethylmethylene groups are preferred.

[0067] In the phenylmaleimide compound represented by formula (6) above, it is preferable that the number of repetitions, s, is 1 < s < 5. This s is the average value of the number of repetitions (degree of polymerization).

[0068]

[0069] In equation (7) above, s represents 1 < s < 5. This s is the same as s in equation (6) above, and is the average value of the number of repetitions (degree of polymerization).

[0070] Commercially available phenylmaleimide compounds can also be used, for example, the solid content in "MIR-5000-60T" manufactured by Nippon Kayaku Co., Ltd., and the solid content in "NE-X-9470S" manufactured by DIC Corporation.

[0071] Phenylmaleimide compounds having an indane structure and an arylene structure bonded to the meta position in their molecule contain not only the arylene and indane structures, but also a phenylmaleimide group in their molecule. The arylene and indane structures are as described above. Specific examples of such phenylmaleimide compounds include those represented by the following formulas (8) to (10).

[0072]

[0073] In equation (8) above, n represents a value between 0.95 and 10.

[0074]

[0075] In equation (9) above, n represents a value between 0.95 and 10.

[0076]

[0077] In the above formula (10), n represents a value between 0.95 and 10.

[0078] Furthermore, the phenylmaleimide compound (A-12) may be a phenylmaleimide compound that does not have at least one of the following structures in its molecule: an indan structure and an arylene structure bonded in a meta position. Examples of such phenylmaleimide compounds (A-12) include 4,4'-diphenylmethanebismaleimide, polyphenylmethanemaleimide, m-phenylenebismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, and biphenylaralkyl type polymaleimide compounds.

[0079] As the phenylmaleimide compound (A-12), any of the phenylmaleimide compounds described above may be used individually, or two or more may be used in combination.

[0080] Furthermore, the resin composition may contain only one of the above-described radical polymerizable compounds (A-1), or it may contain a combination of two or more, as long as the effects of maintaining a low coefficient of thermal expansion during curing and high storage stability according to this embodiment are not impaired.

[0081] The content of radical polymerizable compound (A-1) (total content if two or more radical polymerizable compounds (A-1) are included) is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 12% by mass or more, and particularly preferably 15% by mass, 18% by mass, and 20% by mass or more, based on 100% by mass of the total resin components including the thermosetting resin (A) and the styrene polymer (B). The upper limit of the content of radical polymerizable compound (A-1) is not particularly limited, but the content is preferably 60% by mass or less, more preferably 55% by mass or less, even more preferably 50% by mass or less, and particularly preferably 40% by mass, 35% by mass, 30% by mass, and 28% by mass, based on the total amount of resin components including the thermosetting resin (A) and the styrene polymer (B).

[0082] In this specification, "resin component" means the thermosetting resin (A) and styrene polymer (B) contained in the resin composition, as well as any other organic components that may be optionally included.

[0083] (Reactive compound (A-2)) Reactive compound (A-2) is a different compound from the radical polymerizable compound (A-1) described above. Reactive compound (A-2) is a different compound from the radical polymerizable compound (A-1) and is not particularly limited as long as it is a compound that reacts with the radical polymerizable compound (A-1) described above and undergoes thermosetting.

[0084] Specifically, the reactive compound (A-2) is not particularly limited, but it is preferable that it includes at least one selected from the group consisting of N-alkylmaleimide compounds (A-21), epoxy compounds (A-22), allyl compounds (A-23), and polyphenylene ether compounds having a carbon-carbon unsaturated double bond (A-24) (hereinafter also referred to as "modified polyphenylene ether compound (A-24)").

[0085] If the reactive compound (A-2) includes at least one selected from the group consisting of these compounds, it is possible to more reliably achieve the effect of maintaining a low thermal expansion coefficient during curing and high storage stability according to this embodiment by reacting with the radical polymerizable compound (A-1), and in particular, the thermal expansion coefficient at high temperatures (for example, about 200°C to 240°C) can be reduced more significantly and reliably.

[0086] The N-alkylmaleimide compound (A-21) is a compound different from the phenylmaleimide compound (A-12) described above, and is not particularly limited as any known compound that can be commonly used by those skilled in the art, in which an alkyl group is bonded to the nitrogen atom of maleimide. Examples of N-alkylmaleimide compounds (A-21) include N-alkylbismaleimide compounds having an aliphatic skeleton. More specifically, examples include compounds represented by the following formulas (A-21-1) and (A-21-2).

[0087]

[0088] Commercially available N-alkylmaleimide compounds (A-21) can also be used. Examples of commercially available N-alkylmaleimide compounds (A-21) include "BMI-TMH" manufactured by Yamato Chemical Industries, Ltd., bismaleimide "UMI-0" (a compound represented by the above formula (A-21-2)) manufactured by Unitika Ltd., "SLK-6895" manufactured by Shin-Etsu Chemical Co., Ltd., and "BMI-689" and "BMI-1500" manufactured by Signer Molecules Inc.

[0089] The N-alkylmaleimide compound (A-21) may be used alone or in combination of two or more types.

[0090] The epoxy compound (A-22) is not particularly limited as long as it has at least one epoxy group, and any known epoxy compound that can be commonly used by those skilled in the art may be used. Examples include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, aralkyl epoxy compounds, phenol novolac type epoxy compounds, alkylphenol novolac type epoxy compounds, biphenyl type epoxy compounds, biphenylene type epoxy compounds, bisphenol type epoxy compounds, naphthalene type epoxy compounds, dicyclopentadiene type epoxy compounds, epoxidized products of condensates of phenols and aromatic aldehydes having phenolic hydroxyl groups, triglycidyl isocyanurates, alicyclic epoxy compounds, and the like.

[0091] The epoxy compound (A-22) may be used alone or in combination of two or more types.

[0092] The allyl compound (A-23) is a compound having an allyl group in its molecule and is not particularly limited to any known compound that can be commonly used by those skilled in the art. Preferably, the allyl compound (A-23) is an allylbenzoxazine compound having an allyl group in its molecule.

[0093] Commercially available allylbenzoxazine compounds can also be used. For example, ALP-d type benzoxazine compounds manufactured by Shikoku Chemicals, Inc. can be used.

[0094] The allyl compound (A-23) does not have to be an allylbenzoxazine compound. For example, the allyl compound (A-23) may be a triallyl isocyanurate compound such as triallyl isocyanurate (TAIC), a diallylbisphenol compound, diallyl phthalate (DAP), etc.

[0095] The allyl compound (A-23) may be used alone or in combination of two or more types.

[0096] The modified polyphenylene ether compound (A-24) is not particularly limited, as long as it is any thermosetting resin known to those skilled in the art that has a carbon-carbon unsaturated double bond and a polyphenylene ether chain in its molecule. Examples of the modified polyphenylene ether compound (A-24) include polyphenylene ether compounds that are terminally modified with substituents having a styrene structure or (meth)acrylate structure as shown in formula (11) or formula (12) below.

[0097]

[0098]

[0099] In the above formula (12), R ８ This represents a hydrogen atom or an alkyl group. The alkyl group is not particularly limited, but for example, alkyl groups having 1 to 18 carbon atoms are preferred, and alkyl groups having 1 to 10 carbon atoms are more preferred. Specifically, examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a hexyl group, a decyl group, and the like.

[0100] More specifically, substituents having a carbon-carbon unsaturated double bond include vinyl benzyl groups (ethenyl benzyl groups) such as p-ethenylbenzyl groups and m-ethenylbenzyl groups, vinylphenyl groups, acrylate groups, methacrylate groups, and the like.

[0101] The weight-average molecular weight Mw of the modified polyphenylene ether compound is not particularly limited, but is preferably 1000 to 5000, and more preferably 1000 to 4000. In this specification, the weight-average molecular weight Mw of the modified polyphenylene ether compound is the value measured using gel permeation chromatography (GPC), which is a common molecular weight measurement method. Furthermore, if the modified polyphenylene ether compound has repeating units (s, m, n) in the molecule, it is preferable that these repeating units are values ​​such that the weight-average molecular weight of the modified polyphenylene ether compound falls within this range. When the weight-average molecular weight Mw of the modified polyphenylene ether compound is within this range, it is thought that it will have excellent low dielectric properties derived from the polyphenylene ether skeleton, and that the heat resistance of the cured product and the moldability of the resin composition will be improved.

[0102] The average number of substituents at the molecular ends of a single molecule of the modified polyphenylene ether compound (the number of terminal functional groups in the modified polyphenylene ether compound) is not particularly limited. Specifically, the number of terminal functional groups is preferably 1 to 5, and more preferably 1 to 3. When the number of terminal functional groups is within this range, it is thought that both the heat resistance of the cured product and the moldability of the resin composition are improved.

[0103] Furthermore, "the number of terminal functional groups in a modified polyphenylene ether compound" refers to the average number of substituents present in one mole of the modified polyphenylene ether compound per molecule of that compound.

[0104] Modified polyphenylene ether compounds may be synthesized by any method known to those skilled in the art, or commercially available products may be used. Examples of commercially available products include "OPE-2st 1200" and "OPE-2st 2200" from Mitsubishi Gas Chemical Company, Inc., and "SA9000" from SABIC Innovative Plastics Corporation.

[0105] Modified polyphenylene ether compounds (A-24) can be used alone or in combination of two or more types.

[0106] Furthermore, the resin composition may contain only one of the reactive compounds (A-2) described above, or it may contain a combination of two or more.

[0107] The total content of reactive compound (A-2) is preferably 15% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, and particularly preferably selected from the group consisting of 30% by mass, 33% by mass, 35% by mass and 39% by mass, based on 100% by mass of the total resin components including thermosetting resin (A) and styrene polymer (B). The upper limit of the total content of reactive compound (A-2) is not particularly limited, but the content is preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 55% by mass or less, and particularly preferably selected from the group consisting of 50% by mass, 48% by mass and 45% by mass, based on 100% by mass of the total resin components including thermosetting resin (A) and styrene polymer (B).

[0108] Furthermore, the content of the reactive compound (A-2) is preferably 10 parts by mass or more and 90 parts by mass or less per 100 parts by mass of the radical polymerizable compound (A-1). More preferably, the content of the reactive compound (A-2) is 10 parts by mass or more and 70 parts by mass or less per 100 parts by mass of the radical polymerizable compound (A-1), and even more preferably 10 parts by mass or more and 50 parts by mass or less.

[0109] [Styrene polymer (B)] The resin composition contains a styrene polymer (B) that is solid at 25°C. Including styrene polymer (B) in the resin composition can improve low thermal expansion properties, mainly during curing.

[0110] Examples of styrene polymers (B) include those that are solid at 25°C and can be used as a resin in resin compositions used to form insulating layers in metal-clad laminates, wiring boards, etc. The resin composition used to form insulating layers in metal-clad laminates, wiring boards, etc. may be a resin composition used to form resin layers in resin-coated films, resin-coated metal foils, etc., or a resin composition contained in a prepreg.

[0111] Examples of styrene-based polymers (B) include copolymers obtained by copolymerizing one or more monomers containing styrene (styrene-based monomers) with one or more other monomers copolymerizable with styrene-based monomers. Styrene-based polymers (B) may be random copolymers or block copolymers. Examples of block copolymers include binary copolymers of structural units (repeating units) derived from styrene-based monomers and structural units (repeating units) derived from other copolymerizable monomers, and ternary copolymers of structures (repeating units) derived from styrene-based monomers and structural units (repeating units) derived from other copolymerizable monomers.

[0112] The styrene monomers are not particularly limited, but examples include styrene, styrene derivatives, styrene in which some of the hydrogen atoms of the benzene ring are substituted with alkyl groups, styrene in which some of the hydrogen atoms of the vinyl group are substituted with alkyl groups, vinyltoluene, α-methylstyrene, butylstyrene, dimethylstyrene, isopropenyltoluene, and the like. These styrene monomers may be used individually or in combination of two or more types.

[0113] Furthermore, it is preferable that the styrene polymer (B) contains ethylene structural units and butylene structural units in its molecule, which are obtained by copolymerizing a styrene monomer with one or more other copolymerizable monomers. In particular, it is preferable that the styrene polymer (B) contains a larger proportion of butylene structural units than ethylene structural units.

[0114] The ethylene structural unit is not particularly limited, but examples include structural units (repeating units) derived from other copolymerizable monomers that have an ethylene structure. The ethylene structural unit is a structure derived from the 1,4-bond of a conjugated diene monomer (conjugated dienes), and the atom or group bonded to the carbon of the -C-C-bond in the main chain is a hydrogen atom or a methyl group. Specific examples of conjugated diene monomers include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-cyclohexadiene. Therefore, as ethylene structural units, specifically, examples include structural units derived from conjugated dienes that have an ethylene structure, and more specifically, examples include structural units derived from 1,3-butadiene (repeating units) that have an ethylene structure (1,4-addition structural units).

[0115] The butylene structural unit is not particularly limited, but examples include structural units (repeating units) derived from other copolymerizable monomers that have a butylene structure. The butylene structural unit is at least one of a structure derived from a 1,2-bond of a conjugated diene monomer (conjugated dienes) and a structure derived from a 3,4-bond of a conjugated diene monomer (conjugated dienes), and at least one of the atoms or groups bonded to the carbon of the -C-C-bond of the main chain is a side chain with two or more carbon atoms. Therefore, specific examples of butylene structural units include structural units derived from conjugated dienes that have a butylene structure, and more specifically, structural units (repeating units) derived from 1,3-butadiene that have a butylene structure (at least one of a 1,2-addition structural unit and a 3,4-addition structural unit). The butylene structural unit may also be, for example, a hydrogenated structural unit.

[0116] The styrene polymer (B) may contain structural units (repeating units) derived from other copolymerizable monomers other than ethylene and butylene structural units. Such other copolymerizable monomers are not particularly limited, but examples include olefins such as α-pinene, β-pinene, and dipentene, and non-conjugated dienes such as 1,4-hexadiene and 3-methyl-1,4-hexadiene.

[0117] Specific examples of styrene-based polymers (B) include methylstyrene (ethylene / butylene) methylstyrene copolymer, methylstyrene (ethylene-ethylene / propylene) methylstyrene copolymer, styrene isoprene copolymer, styrene isoprene styrene copolymer, styrene (ethylene / butylene) styrene copolymer, styrene (ethylene-ethylene / propylene) styrene copolymer, styrene butadiene styrene copolymer, and styrene (butadiene / butylene) styrene copolymer.

[0118] The styrene polymer (B) may be a styrene polymer in which at least a portion of the styrene polymer is hydrogenated. It is more preferable that it contains a hydrogenated styrene polymer. This has the advantage that the resulting cured product has a lower coefficient of thermal expansion.

[0119] Examples of hydrogenated styrene polymers include hydrogenated styrene polymers. More specifically, examples of hydrogenated styrene polymers include hydrogenated methylstyrene (ethylene / butylene) methylstyrene copolymer, hydrogenated methylstyrene (ethylene-ethylene / propylene) methylstyrene copolymer, hydrogenated styrene isoprene copolymer, hydrogenated styrene isoprene styrene copolymer, hydrogenated styrene (ethylene / butylene) styrene copolymer, hydrogenated styrene (ethylene-ethylene / propylene) styrene copolymer, hydrogenated methylstyrene (styrene / butadiene random copolymer block) hydrogenated methylstyrene copolymer, and hydrogenated styrene (styrene / butadiene random copolymer block) styrene copolymer.

[0120] In this embodiment, the styrene polymer (B) includes an acid-modified styrene polymer (B-1) and another styrene polymer (B-2) different from the acid-modified styrene polymer (B-1). It is assumed that by including both the acid-modified styrene polymer (B-1) and the other styrene polymer (B-2) in the resin composition within a predetermined mass ratio range, it is possible to maintain a low coefficient of thermal expansion during curing, prevent the separation of the varnish in the resin composition, and improve storage stability.

[0121] The following describes each styrene-based polymer.

[0122] (Acid-modified styrene polymer (B-1)) The acid-modified styrene polymer (B-1) is not particularly limited as long as at least a portion of the aforementioned styrene polymer is an acid-modified styrene polymer.

[0123] The type of acid used for acid modification is not particularly limited as long as the effects of low thermal expansion coefficient and high storage stability according to this embodiment can be obtained. For example, examples of acids include maleic acid, acrylic acid, itaconic acid, methacrylic acid, phthalic acid, maleic anhydride, succinic anhydride, itaconic anhydride, and phthalic anhydride. Of these, from the viewpoint of more reliably obtaining the effects according to this embodiment, it is preferable that the acid-modified styrene polymer (B-1) is acid-modified with maleic anhydride.

[0124] When the resin composition contains not only other styrene-based polymers (B-2) but also acid-modified styrene-based polymers (B-1), its compatibility with the thermosetting resin (A) improves, which not only improves the low thermal expansion properties of the cured product but also suppresses separation during varnish production. As a result, it is expected that the storage stability of the resin composition will also be enhanced.

[0125] The total amount (mass%) of structural units derived from monomers containing styrene in the acid-modified styrene polymer (B-1) is preferably 10% by mass or more and 50% by mass or less of the total amount of the acid-modified styrene polymer (B-1). It is assumed that if the total amount of structural units derived from monomers containing styrene in the acid-modified styrene polymer (B-1) is 10% by mass or more, the low thermal expansion properties during curing of the resin composition can be reliably improved. It is assumed that if the total amount of structural units derived from monomers containing styrene is 50% by mass or less, a better balance can be achieved between maintaining a low thermal expansion coefficient during curing and the storage stability of the varnish of the resin composition.

[0126] In the acid-modified styrene polymer (B-1), the total amount of structural units derived from monomers containing styrene is more preferably 11% by mass or more, and even more preferably 12% by mass or more. Furthermore, in the acid-modified styrene polymer (B-1), the total amount of structural units derived from monomers containing styrene is more preferably 40% by mass or less, even more preferably 35% by mass or less, and particularly preferably less than 30% by mass.

[0127] The weight-average molecular weight of the acid-modified styrene polymer (B-1) is preferably 10,000 to 300,000, and more preferably 30,000 to 200,000. In this specification, the weight-average molecular weight can be any value measured by a general molecular weight measurement method, specifically, a value measured using gel permeation chromatography (GPC).

[0128] Furthermore, commercially available acid-modified styrene polymers (B-1) can also be used, such as "M1913," "M1943," "M1911," and "M1981" manufactured by Asahi Kasei Corporation.

[0129] The acid-modified styrene polymer (B-1) may be used alone or in combination of two or more types.

[0130] The content of the acid-modified styrene polymer (B-1) is not particularly limited as long as it satisfies the mass ratio conditions of the acid-modified styrene polymer (B-1) and other styrene polymers (B-2) according to this embodiment. However, it is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and particularly preferably 20% by mass, 23% by mass, and 25% by mass or more, based on 100% by mass of the total resin components including the thermosetting resin (A) and the styrene polymer (B). The upper limit of the content of the acid-modified styrene polymer (B-1) is not particularly limited as long as the conditions for the mass ratio of the acid-modified styrene polymer (B-1) to the other styrene polymer (B-2) according to this embodiment are met. However, the content is preferably 60% by mass or less, more preferably 55% by mass or less, even more preferably 45% by mass or less, and particularly preferably less than or equal to a value selected from the group consisting of 40% by mass, 35% by mass, 33% by mass, and 29% by mass, based on the total amount of resin components including the thermosetting resin (A) and the styrene polymer (B).

[0131] (Other styrene polymers (B-2)) Other styrene polymers (B-2) are not acid-modified and are not limited to any styrene polymer (B) that does not fall under the above-mentioned acid-modified styrene polymer (B-1).

[0132] It is assumed that if the resin composition contains both an acid-modified styrene polymer (B-1) and another styrene polymer (B-2), a suitable balance can be achieved between maintaining a low coefficient of thermal expansion during curing and the storage stability of the resin composition.

[0133] The total amount (mass%) of structural units derived from monomers containing styrene in the other styrene-based polymer (B-2) is preferably 10% by mass or more and 70% by mass or less of the total amount of the other styrene-based polymer (B-2). If the total amount of structural units derived from monomers containing styrene in the other styrene-based polymer (B-2) is 10% by mass or more, it is assumed that the low thermal expansion properties during curing of the resin composition can be reliably improved. If the total amount of structural units derived from monomers containing styrene is 70% by mass or less, it is assumed that a better balance can be achieved between maintaining a low thermal expansion coefficient during curing and the storage stability of the varnish of the resin composition.

[0134] In other styrene-based polymers (B-2), the total amount of structural units derived from monomers containing styrene is more preferably 15% by mass or more, and even more preferably 20% by mass or more. Furthermore, in other styrene-based polymers (B-2), the total amount of structural units derived from monomers containing styrene is more preferably 65% ​​by mass or less, and even more preferably 60% by mass or less.

[0135] The weight-average molecular weight of the other styrene polymer (B-2) is preferably 10,000 to 300,000, and more preferably 50,000 to 200,000.

[0136] Other styrene polymers (B-2) can be commercially available products, such as "V9827," "V9461," "2002," and "7125F" from Kuraray Co., Ltd., "FTR2140" and "FTR6125" from Mitsui Chemicals, Inc., and "H1221," "H1251," "H1041," "H1043," and "H1517" from Asahi Kasei Corporation.

[0137] Other styrene polymers (B-2) may be used individually or in combination of two or more.

[0138] In the resin composition according to this embodiment, the mass ratio of the acid-modified styrene polymer (B-1) to the other styrene polymer (B-2) (acid-modified styrene polymer (B-1): other styrene polymer (B-2)) is adjusted to be within the range of 5:95 to 95:5. When the resin composition contains the acid-modified styrene polymer (B-1) and the other styrene polymer (B-2) in a mass ratio within this range, these polymers are included in a suitable balance, and it is assumed that the storage stability of the resin composition can be improved while maintaining a low coefficient of thermal expansion during curing.

[0139] The mass ratio of the acid-modified styrene polymer (B-1) to the other styrene polymer (B-2) (acid-modified styrene polymer (B-1): other styrene polymer (B-2)) is preferably 30:70 to 90:10, more preferably 50:50 to 90:10, even more preferably 60:40 to 90:10, and particularly preferably 70:30 to 90:10, 75:25 to 87:13, or 78:22 to 84:16.

[0140] The content of styrene polymer (B) is preferably 1% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and particularly preferably 25% by mass, 28% by mass, and 30% by mass or more, based on 100% by mass of the total resin components including thermosetting resin (A) and styrene polymer (B).

[0141] [Inorganic Filler (C)] The resin composition preferably contains an inorganic filler (C) to the extent that it does not impair the effects of this embodiment. It is believed that the resin composition containing an inorganic filler (C) can further reduce the thermal expansion coefficient of the resin composition during curing.

[0142] The inorganic filler (C) is not particularly limited as long as it is an inorganic filler that can be used as an inorganic filler contained in the resin composition. Examples of materials for the inorganic filler (C) include metal oxides, metal hydroxides, molybdates, nitrides, titanates, magnesium carbonate such as anhydrous magnesium carbonate, calcium carbonate, quartz glass, talc, aluminum borate, and barium sulfate. Examples of metal oxides include silica, alumina, titanium oxide, magnesium oxide, and mica. Examples of silica include crushed silica, spherical silica such as molten spherical silica, and silica particles. Examples of metal hydroxides include magnesium hydroxide and aluminum hydroxide. Examples of molybdates include zinc molybdate, calcium molybdate, and magnesium molybdate. Examples of nitrides include aluminum nitride and boron nitride. Examples of titanates include barium titanate, strontium titanate, calcium titanate, and aluminum titanate. Among these, at least one filler is preferred, which is made of a material selected from the group consisting of silica, metal hydroxides such as magnesium hydroxide and aluminum hydroxide, and aluminum oxide, boron nitride, strontium titanate, calcium titanate, zinc molybdate, etc. Silica filler is more preferred.

[0143] The inorganic filler (C) may be used alone or in combination of two or more types. When using two or more of the inorganic fillers in combination, silica filler may be used in combination with one or more inorganic fillers other than silica.

[0144] The inorganic filler (C) may be a surface-treated inorganic filler or an untreated inorganic filler. Examples of surface treatments include treatment with a silane coupling agent.

[0145] Silane coupling agents are not particularly limited and include, for example, silane coupling agents having at least one functional group selected from the group consisting of vinyl group, styryl group, methacryloyl group, acryloyl group, phenylamino group, isocyanurate group, ureido group, mercapto group, isocyanate group, epoxy group, and acid anhydride group. That is, this silane coupling agent has at least one of vinyl group, styryl group, methacryloyl group, acryloyl group, phenylamino group, isocyanurate group, ureido group, mercapto group, isocyanate group, epoxy group, and acid anhydride group as a reactive functional group. Furthermore, the silane coupling agent may also be a compound having a hydrolyzable group such as a methoxy group or an ethoxy group.

[0146] Examples of silane coupling agents having a vinyl group include vinyltriethoxysilane and vinyltrimethoxysilane. Examples of silane coupling agents having a styryl group include p-styryltrimethoxysilane and p-styryltriethoxysilane. Examples of silane coupling agents having a methacryloyl group include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropylethyldiethoxysilane. Examples of silane coupling agents having an acryloyl group include 3-acryloxypropyltrimethoxysilane and 3-acryloxypropyltriethoxysilane. Examples of silane coupling agents that have a phenylamino group include N-phenyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltriethoxysilane.

[0147] The inorganic filler (C) content is preferably 50 parts by mass or more and 300 parts by mass or less per 100 parts by mass of the total resin components including the thermosetting resin (A) and the styrene polymer (B). This is thought to have the advantage of allowing the cured product to have a lower coefficient of thermal expansion.

[0148] The inorganic filler (C) content is more preferably 60 parts by mass or more, even more preferably 70 parts by mass or more, and particularly preferably 80 parts by mass or more. Furthermore, the inorganic filler (C) content is more preferably 280 parts by mass or less, even more preferably 250 parts by mass or less, and particularly preferably 200 parts by mass or less.

[0149] [Other Components] The resin composition may contain components other than those described above (other components) as necessary, to the extent that it does not impair the effects according to this embodiment. Examples of other components include catalysts such as reaction initiators and reaction accelerators, flame retardants, polymerization inhibitors, polymerization retardants, free radical compounds, flame retardant aids, defoamers, leveling agents, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, dyes, pigments, dispersants, lubricants, and other additives.

[0150] The reaction initiator is not particularly limited as long as it can promote the curing reaction of the thermosetting resin composition, and examples include peroxides and organic azo compounds. Examples of peroxides include α,α'-di(t-butylperoxy)diisopropylbenzene (PBP), 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexine, and benzoyl peroxide. Examples of organic azo compounds include azobisisobutyronitrile. In addition, metal carboxylate salts can be used in combination as needed. Doing so can further promote the curing reaction. The reaction initiator may be used alone or in combination of two or more types.

[0151] The curing accelerator is not particularly limited as long as it can accelerate the curing reaction of the thermosetting resin composition. Specific examples of curing accelerators include imidazoles or their derivatives, organophosphorus compounds, amines such as secondary and tertiary amines, quaternary ammonium salts, organoboron compounds, and metal soaps. Examples of imidazoles include 2-ethyl-4-methylimidazole (2E4MZ), 2-methylimidazole, 2-phenyl-4-methylimidazole, 2-phenylimidazole, and 1-benzyl-2-methylimidazole. Examples of organophosphorus compounds include triphenylphosphine, diphenylphosphine, phenylphosphine, tributylphosphine, and trimethylphosphine. Examples of amines include dimethylbenzylamine, triethylenediamine, triethanolamine, and 1,8-diazabicyclo(5,4,0)undecene-7 (DBU). Furthermore, examples of quaternary ammonium salts include tetrabutylammonium bromide. Examples of organoboron compounds include tetraphenylboron salts such as 2-ethyl-4-methylimidazole tetraphenylborate, and tetrasubstituted phosphonium tetrasubstituted borates such as tetraphenylphosphonium ethyltriphenylborate. Furthermore, metal soaps refer to fatty acid metal salts, which may be linear or cyclic fatty acid metal salts. Specifically, examples of metal soaps include linear aliphatic metal salts and cyclic aliphatic metal salts having 6 to 10 carbon atoms. More specifically, examples include aliphatic metal salts consisting of linear fatty acids such as stearic acid, lauric acid, ricinoleic acid, and octic acid, or cyclic fatty acids such as naphthenic acid, and metals such as lithium, magnesium, calcium, barium, copper, and zinc. For example, zinc octoate is an example. The curing accelerator may be used alone or in combination of two or more types.

[0152] [Physical Properties of the Resin Composition] The glass transition temperature (°C) of the cured resin composition according to this embodiment is preferably 300°C or lower. When the glass transition temperature (Tg) of the cured product is 300°C or lower, it is expected that the coefficient of thermal expansion at high temperatures (approximately 200°C to 240°C) can be significantly reduced. The glass transition temperature (Tg) of the cured product is more preferably 280°C or lower, and particularly preferably 260°C or lower.

[0153] [Uses of the Resin Composition] The resin composition according to this embodiment is mainly used in the manufacture of prepregs, as will be described later. In addition to prepregs, the resin composition is also used in forming resin layers in resin-coated metal foils and resin-coated films, as well as insulating layers in metal-clad laminates and wiring boards.

[0154] Furthermore, the resin composition according to this embodiment provides a resin composition that can maintain a low coefficient of thermal expansion during curing and also has improved storage stability. For this reason, the resin composition is suitably used for semiconductor package substrate applications to reduce substrate warping and improve substrate uniformity.

[0155] The wiring board may be a multilayer wiring board with four or more circuit layers, and the resin composition according to this embodiment can be suitably used as an insulating material for the insulating layer of such a multilayer wiring board. According to the resin composition according to this embodiment, even in such a multilayer wiring board, the wiring density can be increased, the signal transmission speed can be increased, and the signal transmission loss can be reduced. Furthermore, even when applied to a multilayer wiring board equipped with conductive through-holes and / or vias, the signal transmission speed can be increased and the signal transmission loss can be reduced.

[0156] [Method for preparing the resin composition] The method for preparing the resin composition according to this embodiment is not particularly limited and can be prepared by any method known to those skilled in the art. Examples of methods for preparing the resin composition include mixing a thermosetting resin (A) (a radical polymerizable compound (A-1) and a reactive compound (A-2)), an acid-modified styrene polymer (B-1), another styrene polymer (B-2), and other optionally added components in an appropriate mixing ratio, and then optionally adding an inorganic filler (C) as described later. Specifically, when obtaining a varnish-like composition containing an organic solvent, the method described in the prepreg description below can be used.

[0157] <Prepreg, metal-clad laminate, wiring board, resin-coated metal foil, and resin-coated film> Next, a prepreg for a wiring board, a metal-clad laminate, a wiring board, resin-coated metal foil, and a resin-coated film using the resin composition according to the above embodiment will be described.

[0158] [Prepreg] Figure 1 is a schematic cross-sectional view showing an example of a prepreg according to an embodiment of the present invention. In Figure 1, each reference numeral indicates a prepreg 1, a resin composition or a semi-cured product of a resin composition 2, and a fibrous substrate 3, respectively.

[0159] As shown in Figure 1, the prepreg 1 comprises a resin composition or a semi-cured product 2 of the resin composition and a fibrous base material 3. Specifically, the prepreg 1 comprises a resin composition or a semi-cured product 2 of the resin composition and a fibrous base material 3 present in the resin composition or the semi-cured product 2 of the resin composition.

[0160] In this specification, "semi-cured product" means a resin composition that has been cured to a degree that allows for further curing. That is, semi-cured product 2 is a resin composition that has been partially cured (staged to B). Specifically, when a resin composition is heated, its viscosity gradually decreases at first. Then, the curing of the resin composition begins, and the viscosity of the composition gradually increases. In such a case, semi-cured product 2 refers to a resin composition in the state between when the viscosity begins to increase and when the resin composition is completely cured.

[0161] The prepreg 1 obtained using the resin composition according to the above-described embodiment may comprise a semi-cured product 2 of the resin composition as described above, or it may comprise the uncured resin composition itself. That is, the prepreg 1 according to this embodiment may comprise a semi-cured product 2 of the resin composition (B-stage resin composition) and a fibrous substrate 3, or it may comprise an uncured resin composition (A-stage resin composition) and a fibrous substrate 3. The resin composition or the semi-cured product 2 of the resin composition may be obtained by heating and / or drying the resin composition according to the above-described embodiment.

[0162] The resin composition according to the above embodiment is often prepared in a varnish-like form and used as a resin varnish when manufacturing prepreg 1, resin-coated film, resin-coated metal foil, etc., as described later. Such a resin varnish can be prepared, for example, by the method described below.

[0163] First, each component that can be dissolved in an organic solvent, such as the resin component and reaction initiator, is added to the organic solvent and dissolved. The mixed solution may be heated if necessary. Then, inorganic fillers and other components that are insoluble in the organic solvent are added to the mixed solution and dispersed using a ball mill, bead mill, planetary mixer, roll mill, etc., until a predetermined dispersion state is achieved. As a result, a varnish-like resin composition is prepared. The organic solvent that can be used is not particularly limited, as long as it dissolves the thermosetting resin (A) (radical polymerizable compound (A-1) and reactive compound (A-2)), the acid-modified styrene polymer (B-1), other styrene polymers (B-2), and any other optionally added components, without inhibiting the curing reaction. Examples of organic solvents include toluene, methyl ethyl ketone, cyclohexanone, cyclopentanone, methylcyclohexane, dimethylformamide, and propylene glycol monomethyl ether acetate. These organic solvents may be used individually or in combination of two or more.

[0164] A method for producing the prepreg 1 using a varnish-like resin composition includes, for example, impregnating a fibrous substrate 3 with the resin varnish-like resin composition and then drying it.

[0165] Examples of fibrous base materials 3 used in manufacturing prepreg 1 include glass cloth, aramid cloth, polyester cloth, LCP (liquid crystal polymer) nonwoven fabric, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. Of these, using glass cloth as the fibrous base material 3 allows for the production of laminates with excellent mechanical strength. In particular, it is preferable that the glass cloth is flattened glass cloth. Specifically, the type of glass cloth is not particularly limited, but examples include low dielectric constant glass cloths such as E glass, S glass, NE glass, Q glass, and L glass. Flattening can be performed, for example, by continuously pressing the glass cloth with a press roll at an appropriate pressure to flatten the yarn. The thickness of the fibrous base material 3 is not particularly limited and can be a general thickness of, for example, 0.08 mm to 0.3 mm.

[0166] Impregnation of the fibrous substrate 3 with resin varnish (resin composition) can be carried out by dipping and / or coating. This impregnation can be repeated multiple times as needed. In this case, by repeating the impregnation using multiple resin varnishes with different compositions and / or concentrations, the desired composition (content ratio) and / or resin amount can be ultimately adjusted.

[0167] A fibrous substrate 3 impregnated with a resin varnish (resin composition) is heated under desired heating conditions, for example, at a temperature of 40°C to 180°C for about 1 to 10 minutes. By heating, the solvent is evaporated from the varnish, reducing or removing the solvent to obtain a prepreg 1 in a pre-cured state (A-stage resin composition) or a semi-cured state (B-stage resin composition).

[0168] [Metal-clad laminate] Figure 2 is a schematic cross-sectional view showing an example of a metal-clad laminate according to an embodiment of the present invention. In Figure 2, each reference numeral indicates a metal-clad laminate 11, an insulating layer 12, and a metal foil 13, respectively.

[0169] As shown in Figure 2, the metal-clad laminate 11 comprises an insulating layer 12 containing a cured product of the resin composition according to the above embodiment or a cured product of the prepreg 1 described above, and a metal foil 13.

[0170] The metal foil 13 is not particularly limited, and any metal foil known to those skilled in the art and commonly used in metal-clad laminates 11, wiring boards, etc., can be used. For example, the metal foil 13 can be copper foil, aluminum foil, etc.

[0171] The thickness of the metal foil 13 can be set appropriately according to the desired purpose. For example, the thickness of the metal foil 13 can be set to approximately 0.2 μm to 70 μm. For example, if the thickness of the metal foil 13 is 10 μm or less, the metal foil 13 may be a carrier-equipped copper foil with a release layer and a carrier to improve handling.

[0172] The method for manufacturing the metal-clad laminate 11 is not particularly limited, but for example, it can be manufactured using not only the prepreg 1 described above, but also resin-coated metal foil and / or resin-coated film described later.

[0173] Specifically, one or more prepreg 1, a resin-coated metal foil and / or resin-coated film (described later) are stacked, and then metal foil 13 such as copper foil is stacked on both sides or one side of the stack. This is then heated and pressurized to create a laminated, integrated structure. As a result, a laminate with metal foil on both sides or one side can be produced. The conditions for heating and pressurizing can be appropriately set according to the thickness of the laminate to be manufactured, the type of resin composition, etc. For example, the conditions for heating and pressurizing can be 170°C to 230°C, 1.5 MPa to 5.0 MPa, and 60 to 150 minutes.

[0174] Furthermore, the metal-clad laminate 11 may be manufactured without using the prepreg 1, the resin-coated metal foil and / or resin-coated film described later. For example, the aforementioned resin varnish may be applied to the metal foil 13 by coating or other means to form a layer containing the resin composition on the metal foil 13, and then heated and pressurized. The coating or other application may be repeated multiple times as needed. In this case, it is also possible to adjust to the desired composition (content ratio) and amount of resin by repeatedly applying multiple resin varnishes with different compositions and concentrations.

[0175] [Wiring board] Figure 3 is a schematic cross-sectional view showing an example of a wiring board according to an embodiment of the present invention. In Figure 3, each reference numeral indicates an insulating layer 12, wiring 14, and wiring board 21, respectively.

[0176] As shown in Figure 3, the wiring board 21 comprises an insulating layer 12 containing a cured resin composition according to the above embodiment or a cured prepreg 1, and wiring 14 provided on the insulating layer 12.

[0177] The method for manufacturing the wiring board 21 is not particularly limited, but one example is to obtain a wiring board 21 having a conductor pattern (wiring 14) as a circuit on the surface of the laminate by etching the metal foil 13 on the surface of the metal-clad laminate 11 described above. In addition to the above method, other methods for circuit formation include, for example, the semi-additive process (SAP) and the modified semi-additive process (MSAP).

[0178] [Resin-coated metal foil] Figure 4 is a schematic cross-sectional view showing an example of resin-coated metal foil according to an embodiment of the present invention. In Figure 4, each reference numeral indicates a metal foil 13, a resin-coated metal foil 31, and a resin layer 32, respectively.

[0179] As shown in Figure 4, the resin-coated metal foil 31 according to this embodiment has a structure in which a resin layer 32 containing the resin composition according to the above embodiment or a semi-cured product 2 of the resin composition and a metal foil 13 are laminated together. That is, the resin-coated metal foil 31 may comprise a resin layer 32 containing the resin composition before curing (stage A resin composition) and a metal foil 13, or it may comprise a resin layer 32 containing a semi-cured product 2 of the resin composition (stage B resin composition) and a metal foil 13. The metal foil 13 is the same as the metal foil 13 of the metal-clad laminate 11 described above.

[0180] A method for manufacturing the resin-coated metal foil 31 shown in Figure 4 includes, for example, applying the aforementioned resin varnish to the surface of a metal foil 13 such as copper foil, and then heating and drying it to volatilize the solvent from the varnish, thereby reducing or removing the solvent.

[0181] Examples of coating methods include bar coaters, comma coaters, die coaters, roll coaters, and gravure coaters. The heating and drying conditions can be set to any desired conditions and are not particularly limited, but for example, heating at a temperature of 50°C to 180°C for about 0.1 to 10 minutes is performed. After heating and drying, the resin-coated metal foil 31 should be obtained in a state before curing (resin composition of stage A) or in a semi-cured state (resin composition of stage B). The coating process may be repeated multiple times as needed. Furthermore, by repeatedly applying multiple resin varnishes with different compositions and concentrations, it is possible to finally adjust to the desired composition (content ratio) and amount of resin.

[0182] The resin-coated metal foil 31 may be provided with a cover film or the like, if necessary. Providing a cover film prevents the incorporation of foreign matter into the resin composition, such as in a semi-cured state. The cover film is not particularly limited as long as it can be peeled off without damaging the form of the resin composition. Examples of cover films include polyolefin films, polyester films, TPX films, films formed by providing a release agent layer on these films, and paper obtained by laminating these films onto a paper substrate.

[0183] [Resin-coated film] Figure 5 is a schematic cross-sectional view showing an example of a resin-coated film according to an embodiment of the present invention. In Figure 5, each reference numeral indicates the resin-coated film 41, the resin layer 42, and the film support substrate 43, respectively.

[0184] As shown in Figure 5, the resin-coated film 41 has a structure in which a resin layer 42 containing the resin composition according to the above embodiment or a semi-cured product 2 of the resin composition and a film support substrate 43 are laminated together. That is, the resin-coated film 41 may comprise a resin layer 42 containing the resin composition before curing (stage A resin composition) and a film support substrate 43, or it may comprise a resin layer 42 containing a semi-cured product 2 of the resin composition (stage B resin composition) and a film support substrate 43. Furthermore, the resin layer 42 may contain the resin composition according to the above embodiment or a semi-cured product 2 of the resin composition, and may also contain a fibrous substrate 3.

[0185] A method for manufacturing the resin-coated film 41 shown in Figure 5 includes, for example, applying the aforementioned resin varnish to the surface of the film support substrate 43, and then heating and drying it to volatilize the solvent from the varnish, thereby reducing or removing the solvent.

[0186] The coating method and heating / drying conditions are the same as those for the resin-coated metal foil 31 described above, and should be set so that the resin-coated metal foil 31 is ultimately obtained in a state before curing (resin composition of stage A) or in a semi-cured state (resin composition of stage B).

[0187] The film support substrate 43 is not particularly limited as long as it is any substrate known to those skilled in the art, but examples include electrically insulating films such as polyimide film, PET (polyethylene terephthalate) film, polyester film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, aramid film, polycarbonate film, and polyarylate film.

[0188] The resin-coated film 41 may also be equipped with a cover film or the like, similar to the resin-coated metal foil 31 described above.

[0189] Thus, the prepreg, resin-coated metal foil, resin-coated film, and metal-clad laminate according to this embodiment are manufactured using the resin composition according to the above embodiment, which has a high relative permittivity and a low dielectric loss tangent in its cured product. Therefore, as described above, these are suitably used to form insulating layers provided on high-frequency wiring boards.

[0190] As described above, this specification discloses various aspects of technology, the main technologies among them are summarized below.

[0191] A resin composition according to a first aspect of the present invention contains a thermosetting resin (A) and a styrene polymer (B), wherein the styrene polymer (B) includes an acid-modified styrene polymer (B-1) and another styrene polymer (B-2) different from the acid-modified styrene polymer (B-1), and the mass ratio of the acid-modified styrene polymer (B-1) to the other styrene polymer (B-2) is 5:95 to 95:5.

[0192] A resin composition according to a second aspect of the present invention is a resin composition according to a first aspect, wherein the total amount of structural units derived from monomers containing styrene in the acid-modified styrene polymer (B-1) is 10% by mass or more and 50% by mass or less, relative to the total amount of the acid-modified styrene polymer (B-1).

[0193] A resin composition according to a third aspect of the present invention is a resin composition according to a first or second aspect, wherein the total amount of structural units derived from monomers containing styrene in the other styrene polymer (B-2) is 10% by mass or more and 70% by mass or less, relative to the total amount of the other styrene polymer (B-2).

[0194] A resin composition according to the fourth aspect of the present invention is a resin composition according to any one of the first to third aspects, wherein the molecular weight of the acid-modified styrene polymer (B-1) is 10,000 or more and 300,000 or less, and the molecular weight of the other styrene polymer (B-2) is 10,000 or more and 300,000 or less.

[0195] A fifth aspect of the present invention is a resin composition according to any of the first to fourth aspects, wherein the content of styrene polymer (B) is 1% by mass or more and 50% by mass or less, based on 100% by mass of the total resin components including thermosetting resin (A) and styrene polymer (B).

[0196] A resin composition according to the sixth aspect of the present invention is a resin composition according to any one of the first to fifth aspects, wherein the acid-modified styrene polymer (B-1) includes a styrene polymer that has been acid-modified with maleic acid.

[0197] The seventh aspect of the present invention is a resin composition according to any of the first to sixth aspects, comprising an inorganic filler (C), wherein the amount of inorganic filler (C) is 50 parts by mass or more and 300 parts by mass or less, based on 100 parts by mass of the total resin components including the thermosetting resin (A) and the styrene polymer (B).

[0198] The eighth aspect of the present invention is a resin composition according to any of the first to seventh aspects, wherein the thermosetting resin (A) comprises a radical polymerizable compound (A-1), and the radical polymerizable compound (A-1) comprises at least one selected from the group consisting of hydrocarbon compounds having an indene ring and / or a fluorene ring (A-11) and phenylmaleimide compounds (A-12).

[0199] The resin composition according to the ninth aspect of the present invention is the resin composition according to the eighth aspect, wherein the phenylmaleimide compound (A-12) has at least one structure in the molecule, which is an indan structure and an arylene structure bonded in an orientation at the meta position.

[0200] A resin composition according to the tenth aspect of the present invention is a resin composition according to the eighth or ninth aspect, wherein the thermosetting resin (A) comprises a reactive compound (A-2) different from the radical polymerizable compound (A-1), and the reactive compound (A-2) comprises at least one selected from the group consisting of N-alkylmaleimide compounds (A-21), epoxy compounds (A-22), allyl compounds (A-23), and polyphenylene ether compounds having a carbon-carbon unsaturated double bond (A-24).

[0201] The resin composition according to the eleventh aspect of the present invention is the resin composition according to the tenth aspect, wherein the content of the reactive compound (A-2) is 10 parts by mass or more and 90 parts by mass or less per 100 parts by mass of the radical polymerizable compound (A-1).

[0202] A prepreg according to a twelfth aspect of the present invention comprises a resin layer containing any of the first to eleventh resin compositions or a semi-cured product of the resin composition, a support film, a resin composition or a semi-cured product of the resin composition, and a fibrous substrate.

[0203] A resin-coated film according to the thirteenth aspect of the present invention comprises a resin layer containing a resin composition according to any of the first to eleventh aspects or a semi-cured product of the resin composition, and a support film.

[0204] A resin-coated metal foil according to the 14th aspect of the present invention comprises a resin layer containing a resin composition according to any of the 1st to 11th aspects or a semi-cured product of the resin composition, and a metal foil.

[0205] A metal-clad laminate according to the fifteenth aspect of the present invention comprises an insulating layer containing a cured product of a resin composition according to any of the first to eleventh aspects, and a metal foil.

[0206] A metal-clad laminate according to the sixteenth aspect of the present invention comprises an insulating layer containing a cured product of a resin composition according to any of the first to eleventh aspects, and wiring.

[0207] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by these examples.

[0208] First, the raw materials used to prepare the resin composition in this example are summarized below.

[0209] [Radical Polymerizable Compounds (A-1)] • Hydrocarbon compound having an indene ring: A mixture of 1,1,2-(multiple isomers of 2,3- and 4-vinylbenzyl)-1H-indene (83%) and 1,1-(multiple isomers of 2,3- and 4-vinylbenzyl)-1H-indene (17%) • Phenylmaleimide compound 1: A maleimide compound having an indane structure and an arylene structure bonded to the meta position in its molecule (solid content in "NE-X-9470S" manufactured by DIC Corporation, a maleimide compound represented by the above formula (8)) • Phenylmaleimide compound 2: 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide ("BMI-5100" manufactured by Yamato Chemical Industries, Ltd.) - Phenylmaleimide compound 3: A maleimide compound having an arylene structure substituted at the meta position in its molecule (solid content in "MIR-5000-60T" (toluene-soluble maleimide compound) manufactured by Nippon Kayaku Co., Ltd., maleimide compound represented by the above formula (7), maleimide equivalent 260 g / mol)

[0210] [Reactive Compounds (A-2)] ・N-alkylmaleimide compound: 1,6-bismaleimide (2,2,4-trimethyl)hexane ("BMI-TMH" manufactured by Yamato Chemical Industries, Ltd.) ・Modified polyphenylene ether compound: Polyphenylene ether compound with methacryloyl groups at the terminals ("SA9000" manufactured by SABIC Innovative Plastics, weight-average molecular weight Mw2000, 2 terminal functional groups) ・Allylbenzoxazine compound: ALP-d type benzoxazine compound manufactured by Shikoku Chemicals, Ltd. ・Epoxy compound: Oligomer-type dicyclopentadiene-type epoxy compound represented by the following formula (13) ("HP7200H" manufactured by DIC Corporation)

[0211] - Aliphatic bismaleimide compound 1: Bismaleimide "UMI-0" manufactured by Unitika Ltd., represented by the above formula (A-21-2) - Aliphatic bismaleimide compound 2: "SLK-6895" manufactured by Shin-Etsu Chemical Co., Ltd.

[0212] [Acid-modified styrene polymer (B-1)] ・Acid-modified styrene polymer: A styrene polymer modified with maleic anhydride (M1981 manufactured by Asahi Kasei Corporation, 12% by mass of structural units derived from monomers containing styrene, weight-average molecular weight Mw 140,000, solid at 25°C)

[0213] [Other styrene-based polymers (B-2)] ・Unmodified styrene-based polymer 1: Hydrogenated styrene (ethylene-butylene) styrene block copolymer (Asahi Kasei Corporation's "ToughTec® H1517", weight-average molecular weight Mw 95,000, solid at 25°C, total structural units derived from monomers including styrene: 43% by mass) ・Unmodified styrene-based polymer 2: Styrene (ethylene / butylene) styrene copolymer (Asahi Kasei Corporation's "ToughTec® H1221", weight-average molecular weight Mw 150,000, solid at 25°C, total structural units derived from monomers including styrene: 12% by mass)

[0214] [Inorganic Filler (C)] ・Silica Filler: Amorphous silica (spherical, average particle size 0.5 μm, methacrylate silane surface treatment) ("SC2500-SMJ" manufactured by Admatex Co., Ltd.)

[0215] [Polymerization inhibitor] ・4-BenzoyloxyTEMPO (manufactured by Seiko Chemical Co., Ltd.)

[0216] [Reaction Initiator] Peroxide: α,α'-bis(t-butylperoxy-m-isopropyl)benzene ("Perbutyl P (PBP)" manufactured by NOF Corporation)

[0217] [Curing accelerator] ・Imidazole-based curing accelerator: 2-ethyl-4-methylimidazole ("2E4MZ" manufactured by Shikoku Chemicals Co., Ltd.)

[0218] Next, the methods for preparing the resin composition (varnish) and the methods for manufacturing the evaluation substrate (metal-clad laminate) in each example and comparative example are described below.

[0219] <Examples 1 to 15 and Comparative Examples 1 to 3> (Method for preparing resin composition (varnish)) In each example and comparative example, first, a styrene copolymer component was added to a mixed solvent of toluene and methyl ethyl ketone (MEK) (mass ratio approximately 4:1) in the formulations shown in Tables 1 and 2 below, and stirred while heating at 65°C. Next, the resulting mixture was cooled to 25°C while stirring, and then an indene ring hydrocarbon compound, a phenyl maleimide compound, and a reactive compound (A-2) were added in that order in the formulations shown in Tables 1 and 2 below, and stirred for a further 30 minutes. After that, an inorganic filler and a reaction initiator were added to the mixture in the formulations shown in Tables 1 and 2 below, and the inorganic filler was dispersed in the mixture using a bead mill. After dispersion, a varnish-like resin composition was obtained. The solid content concentration was formulated to be 45% to 52% by mass.

[0220] (Method for preparing evaluation substrates (metal-clad laminates)) The varnish obtained by the method described above was impregnated into a fibrous substrate (glass cloth: #2118 type, T glass, manufactured by Nitto Boseki Co., Ltd.), and then heated and dried at 120°C to 140°C for 3 minutes to prepare a prepreg. At that time, the content of the components constituting the resin in relation to the prepreg (resin content) was adjusted to be approximately 43 to 45% by mass. In addition, the thickness of one prepreg after curing was adjusted to 100 μm.

[0221] Ten of the obtained prepregs were stacked together, and 12 μm thick copper foil (3EC-VLP manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on both sides. This was used as the pressure-bearing body, and it was heated to a temperature of 220°C at a heating rate of 3°C / min. By heating and pressurizing it at 220°C for 120 minutes under a pressure of 5 MPa, an evaluation substrate (metal-clad laminate) with a resin layer thickness of approximately 1000 μm was obtained, with copper foil bonded to both sides.

[0222] The following evaluation tests were performed using the varnishes and evaluation substrates of each example and comparative example obtained by the method described above.

[0223] <Evaluation Test> [Thermal Expansion Coefficient (50°C to 100°C, 50°C to 260°C, and 200°C to 240°C)] An unclad plate, obtained by etching off the copper foil from an evaluation substrate (copper-clad laminate) with a thickness of approximately 1000 μm using the method described above, was used as a test specimen (size: 10 mm × 3.5 mm). The thermal expansion coefficient of the evaluation substrate in the planar direction (tensile direction, Y direction) at a temperature below the glass transition temperature of the cured resin composition was measured by the TMA method (Thermo-mechanical analysis). Specifically, the measurement was performed using a TMA device (TMA7100E manufactured by SII Nanotechnology Co., Ltd.) in compression mode. To eliminate the effect of thermal strain on the test specimen, the specimen was set up so that a load was applied in the Y direction, and the temperature was raised from 30°C to 350°C at a heating rate of 20°C / min, after which it was cooled to room temperature. Subsequently, the temperature was increased again from 30°C to 350°C at a heating rate of 10°C / min. A temperature displacement chart was obtained during this heating process. From the temperature displacement chart obtained at this time, the average thermal expansion coefficients for 50°C to 100°C, 50°C to 260°C, and 200°C to 240°C were calculated. A lower average thermal expansion coefficient ("Y-CTE 50-100°C", "Y-CTE 50-260°C", and "Y-CTE 200-240") indicates a more favorable result. In this test, a "pass" was considered to be achieved if the average thermal expansion coefficients for 50°C to 100°C and 50°C to 260°C were 4.5 ppm / °C or less, and the average thermal expansion coefficient for 200°C to 240°C was 5.0 ppm / °C or less, indicating that a low thermal expansion coefficient was maintained during curing.

[0224] [Storage Stability] The varnish-like resin composition obtained by the method described above was placed in a sample bottle and left for one day. After standing, it was visually inspected to see if the varnish had separated or gelled. If it had not separated or gelled, it was deemed "acceptable" and evaluated as having high storage stability as a varnish.

[0225] [Glass Transition Temperature (Tg)] A resin cured product obtained by etching off the metal foil (copper foil) from the evaluation substrate (metal-clad laminate) obtained by the method described above was used as a test specimen, and the glass transition temperature (Tg) of the cured resin composition was measured using a viscoelastic spectrometer "DMS6100" manufactured by Seiko Instruments Inc. At this time, dynamic viscoelasticity measurement (DMA) was performed with a bending module at a frequency of 10 Hz, and the temperature at which tanδ showed a maximum when the temperature was raised from room temperature to 350°C under the condition of a heating rate of 5°C / min was defined as the glass transition temperature (°C).

[0226] The results of the evaluation tests for each example and comparative example, along with the formulation composition, are summarized in Tables 1 and 2 below. The amounts of each component are shown as mass% of the total amount of resin components for resin components, and as parts by mass per 100 parts by mass of resin components for other components. A "-" in the column of Tables 1 and 2 below means that the component was not included in the resin composition of that example or comparative example.

[0227]

[0228]

[0229] <Discussion> As shown in Tables 1 and 2 above, the resin compositions of Examples 1 to 15, which included not only a thermosetting resin (A) but also an acid-modified styrene polymer (B-1) and another styrene polymer (B-2) in a mass ratio of 5:95 to 95:5 (acid-modified styrene polymer (B-1): other styrene polymer (B-2)), showed high storage stability of the varnish while maintaining a low thermal expansion coefficient during curing.

[0230] Furthermore, among the resin compositions of all the examples, the resin compositions of Examples 4, 5, and 10 to 15 had a lower average thermal expansion coefficient at high temperatures (200°C to 240°C) (4.2 ppm / °C or less), and were able to further reduce the thermal expansion coefficient of the cured product. This is presumed to be because the thermosetting resin (A) in the resin compositions of Examples 4, 5, and 10 to 15 contained both a radical polymerizable compound (A-1) and a reactive compound (A-2).

[0231] In particular, among the resin compositions of the above examples, the resin compositions of Examples 4, 5, and 11 to 15 showed remarkably low average thermal expansion coefficients (3.9 ppm / °C or less) at high temperatures (200°C to 240°C). This is presumed to be because the glass transition temperature (Tg) of the cured products of these resin compositions was all below 300°C.

[0232] On the other hand, the resin composition of Comparative Example 1, which did not contain the other styrene polymer (B-2), showed a high coefficient of thermal expansion during curing, as well as varnish separation and poor storage stability. Comparative Example 2, which did not contain the acid-modified styrene polymer (B-1), also showed a high coefficient of thermal expansion. Furthermore, the resin composition of Comparative Example 3, which did not contain the acid-modified styrene polymer (B-1), also showed varnish separation and poor storage stability.

[0233] The embodiments and examples disclosed herein should be understood in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope of the claims are intended to be included.

[0234] This application is based on Japanese Patent Application No. 2025-056147, filed on 28 March 2025, and its contents are included in this application.

[0235] According to embodiments of the present invention, a resin composition can be obtained that maintains a low coefficient of thermal expansion during curing and also enhances storage stability. For this reason, the resin composition is suitably used in semiconductor package substrates to reduce substrate warpage and improve substrate uniformity.

Claims

1. A resin composition comprising a thermosetting resin (A) and a styrene polymer (B), wherein the styrene polymer (B) comprises an acid-modified styrene polymer (B-1) and another styrene polymer (B-2) different from the acid-modified styrene polymer (B-1), and the mass ratio of the acid-modified styrene polymer (B-1) to the other styrene polymer (B-2) is 5:95 to 95:

5.

2. The resin composition according to claim 1, wherein the total amount of structural units derived from monomers containing styrene in the acid-modified styrene polymer (B-1) is 10% by mass or more and 50% by mass or less, relative to the total amount of the acid-modified styrene polymer (B-1).

3. The resin composition according to claim 1, wherein the total amount of structural units derived from monomers containing styrene in the other styrene-based polymer (B-2) is 10% by mass or more and 70% by mass or less, relative to the total amount of the other styrene-based polymer (B-2).

4. The resin composition according to claim 1, wherein the molecular weight of the acid-modified styrene polymer (B-1) is 10,000 or more and 300,000 or less, and the molecular weight of the other styrene polymer (B-2) is 10,000 or more and 300,000 or less.

5. The resin composition according to claim 1, wherein the content of styrene polymer (B) is 1% by mass or more and 50% by mass or less based on 100% by mass of the total resin components including thermosetting resin (A) and styrene polymer (B).

6. The resin composition according to claim 1, wherein the acid-modified styrene polymer (B-1) comprises a styrene polymer that has been acid-modified with maleic acid.

7. The resin composition according to claim 1, comprising an inorganic filler (C), wherein the amount of inorganic filler (C) is 50 parts by mass or more and 300 parts by mass or less, based on 100 parts by mass of the total resin components including the thermosetting resin (A) and the styrene polymer (B).

8. The resin composition according to claim 1, wherein the thermosetting resin (A) comprises a radical polymerizable compound (A-1), and the radical polymerizable compound (A-1) comprises at least one selected from the group consisting of hydrocarbon compounds having an indene ring and / or a fluorene ring (A-11) and phenylmaleimide compounds (A-12).

9. The resin composition according to claim 8, wherein the phenylmaleimide compound (A-12) has at least one structure in its molecule, which is an indan structure and an arylene structure that is oriented and bonded at the meta position.

10. The resin composition according to claim 8, wherein the thermosetting resin (A) comprises a reactive compound (A-2) different from the radical polymerizable compound (A-1), and the reactive compound (A-2) comprises at least one selected from the group consisting of N-alkylmaleimide compounds (A-21), epoxy compounds (A-22), allyl compounds (A-23), and polyphenylene ether compounds having a carbon-carbon unsaturated double bond (A-24).

11. The resin composition according to claim 10, wherein the content of the reactive compound (A-2) is 10 parts by mass or more and 90 parts by mass or less per 100 parts by mass of the radical polymerizable compound (A-1).

12. A prepreg comprising a resin composition according to any one of claims 1 to 11 or a semi-cured product of the resin composition, and a fibrous substrate.

13. A resin-coated film comprising a resin layer containing the resin composition described in any one of claims 1 to 11 or a semi-cured product of the resin composition, and a support film.

14. A resin-coated metal foil comprising a resin layer containing the resin composition described in any one of claims 1 to 11 or a semi-cured product of the resin composition, and a metal foil.

15. A metal-clad laminate comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 11, and a metal foil.

16. A wiring substrate comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 11, and wiring.

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