Resin composition, and prepreg, resin-coated film, resin-coated metal foil, metal-clad laminate, and wiring board using the same

Abstract

One aspect of the present invention relates to a resin composition which contains: a styrene block copolymer; a radically polymerizable compound; and at least one free radical compound that is selected from the group consisting of a compound (A) represented by formula (1), a compound (B) represented by formula (2), and a compound (C) that has two or more groups that are composed of at least one kind of group selected from among groups represented by formula (3-1) and formula (3-2).

Description

[Technical Field]

[0001] The present invention relates to a resin composition, and to a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board using the same. [Background technology]

[0002] In recent years, with the increase in the amount of information processed in various electronic devices, there has been rapid progress in packaging technologies such as higher integration of mounted semiconductor devices, higher density wiring, and multi-layering. Substrate materials for constituting the base material of wiring boards used in various electronic devices are required to have low dielectric constants and dielectric loss tangents in order to increase signal transmission speeds and reduce loss during signal transmission.

[0003] Polyphenylene ether (PPE) is known to have excellent dielectric properties, such as a low dielectric constant and a low dielectric loss tangent, even in high frequency bands (high frequency regions) from the MHz band to the GHz band. For this reason, polyphenylene ether is being considered for use as, for example, a molding material for high frequencies. More specifically, it is preferably used as a substrate material for constituting the base material of a wiring board included in an electronic device that uses high frequencies.

[0004] For example, Patent Document 1 discloses a resin composition containing a modified polyphenylene ether compound and a styrene-based thermoplastic elastomer having a weight-average molecular weight of 10,000 or more.

[0005] It has been reported that the resin composition disclosed in Patent Document 1 can impart film-forming ability without impairing low dielectric properties and heat resistance.

[0006] On the other hand, in recent years, substrate materials have been required to be thinner, and therefore, better low dielectric properties are required. To achieve this, it has been considered to increase the amount of styrene-based thermoplastic elastomer added, but because the elastomer has a high molecular weight, increasing the content of this elastomer has caused problems with circuit filling properties when the resin composition is used as a substrate material. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-83364 Summary of the Invention

[0008] The present invention has been made in view of the above circumstances, and aims to provide a resin composition which, when cured, has excellent properties such as low dielectric constant, low coefficient of thermal expansion, and high Tg, and which also has excellent circuit filling properties when used as a substrate material. Another aim of the present invention is to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board which use the resin composition.

[0009] A resin composition according to one embodiment of the present invention is characterized by comprising a styrene-based block copolymer, a radically polymerizable compound, and at least one free radical compound selected from the group consisting of a compound (A) represented by the following formula (1), a compound (B) represented by the following formula (2), and a compound (C) having two or more groups each of which is selected from the group represented by the following formula (3-1) and formula (3-2):

[0010] [ka]

[0011] [ka]

[0012] [ka]

[0013] [ka] (In formula (1) and formula (2), X A and X B each independently represents a hydrogen atom, an amino group, a cyano group, a hydroxy group, an isothiocyanate group, a methoxy group, a carboxy group, a carbonyl group, an amido group, or a benzoyloxy group. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view showing the configuration of a prepreg according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing the configuration of a metal-clad laminate according to one embodiment of the present invention. [Figure 3] FIG. 3 is a schematic cross-sectional view showing the configuration of a wiring board according to one embodiment of the present invention. [Figure 4] FIG. 4 is a schematic cross-sectional view showing the structure of a resin-coated metal foil according to one embodiment of the present invention. [Figure 5] FIG. 5 is a schematic cross-sectional view showing the structure of a resin film according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] A resin composition according to an embodiment of the present invention (hereinafter also simply referred to as a resin composition) is characterized by comprising a styrene-based block copolymer, a radically polymerizable compound, and at least one free radical compound selected from the group consisting of compound (A) represented by formula (1), compound (B) represented by formula (2), and compound (C) having two or more groups each of which is at least one group selected from the groups represented by formula (3-1) and formula (3-2).

[0016] By including a styrene-based block copolymer and a radically polymerizable compound, a resin composition can be obtained that exhibits low dielectric properties, a low coefficient of thermal expansion, and a high Tg (glass transition temperature) in the cured product. On the other hand, the use of a styrene-based block copolymer can impair resin flow when used as a resin composition or a semi-cured (B-stage) resin composition, raising concerns about circuit filling. However, by adding a free radical compound as in this embodiment, it is possible to delay the onset of resin curing and lower the minimum melt viscosity. Therefore, it is believed that circuit filling can be improved while maintaining low dielectric properties, a high Tg, and the like.

[0017] As for material properties, a material with a high Tg in the cured product is one factor that contributes to improved heat resistance (e.g., reflow heat resistance). Another advantage of a material with a high Tg in the cured product is that it has a low coefficient of thermal expansion at higher temperatures. Generally, thermal expansion increases rapidly at temperatures above the glass transition temperature. Therefore, if the glass transition temperature is low, the coefficient of thermal expansion increases at high temperatures above the glass transition temperature. A high coefficient of thermal expansion at high temperatures can, for example, reduce interlayer connection reliability (e.g., barrel cracking in through-holes) in wiring boards, potentially preventing the printed circuit board from functioning properly. This is thought to be due to the large difference in thermal expansion coefficients at high temperatures between the insulating layer (made of the cured resin composition) in the board and the metal through-holes, which can lead to cracks in the walls of the metal through-holes and reduced connection reliability.

[0018] That is, according to the present invention, a resin composition can be provided which, when cured, has excellent properties such as low dielectric constant, low coefficient of thermal expansion, and high Tg, and which also has excellent circuit filling properties when used as a substrate material. Furthermore, by using the resin composition, it is possible to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board which have excellent properties.

[0019] Each component of the resin composition according to this embodiment will be specifically described below.

[0020] (styrene-based block copolymer) The resin composition of this embodiment contains a styrene-based block copolymer, which is believed to have advantages such as further reducing the dielectric constant of the resin and improving the handleability (filmability) of the resin composition or a semi-cured product (B-stage) of the resin composition.

[0021] The styrene-based block copolymer used in this embodiment is, for example, a copolymer obtained by block polymerization of a monomer containing a styrene-based monomer. Examples of the styrene-based copolymer include copolymers obtained by block polymerization of one or more styrene-based monomers and one or more other monomers copolymerizable with the styrene-based monomer. Examples of the styrene-based monomer include styrene and styrene derivatives.

[0022] The weight-average molecular weight of the styrene-based block copolymer of this embodiment is preferably about 10,000 to 200,000, and more preferably about 50,000 to 180,000. A weight-average molecular weight within this range has the advantage of ensuring appropriate resin fluidity in the resin composition or in the semi-cured state (B-stage) of the resin composition. In this specification, the weight-average molecular weight may be measured by a general molecular weight measurement method, and specific examples include values ​​measured using gel permeation chromatography (GPC).

[0023] In a preferred embodiment, the styrene-based block polymer of the present embodiment is preferably a styrene-based block copolymer having a hardness of 20 to 100. Furthermore, the hardness of the styrene-based block copolymer is preferably 30 to 80. It is believed that by including a styrene-based block copolymer having a hardness within the above range, a resin composition can be obtained that, when cured, has lower dielectric properties and a cured product with a low thermal expansion coefficient.

[0024] The hardness may be, for example, a durometer hardness, and more specifically, a durometer hardness measured using a type A durometer conforming to JIS K 6253.

[0025] As a specific styrene-based block copolymer, a wide variety of conventionally known copolymers can be used, and there is no particular limitation. For example, a polymer having a structural unit (structure derived from a styrene-based monomer) represented by the following formula (5) in the molecule can be used.

[0026] [ka] In formula (5), R2 to R4 each independently represent a hydrogen atom or an alkyl group, and R5 represents a hydrogen atom, an alkyl group, an alkenyl group, or an isopropenyl group. The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. The alkenyl group is preferably an alkenyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0027] The styrene-based block copolymer of this embodiment preferably contains at least one structural unit represented by the above formula (5), but may contain a combination of two or more different structural units, or may contain a structure in which the structural unit represented by the above formula (5) is repeated.

[0028] Furthermore, the styrene-based block copolymer of the present embodiment may have, in addition to the structural unit represented by the above formula (5), at least one of the structural units represented by the following formulas (6) to (8) as another monomer copolymerizable with the styrene-based monomer.

[0029] [ka]

[0030] [ka]

[0031] [ka]

[0032] In the above formulas (6) to (8), R6 to R 23 are each independently a group selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, and an isopropenyl group. The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. The alkenyl group is preferably an alkenyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group. The styrene-based block copolymer of this embodiment preferably contains at least one structural unit represented by the above formulas (6) to (8), and may contain two or more different structural units in combination. The styrene-based block copolymer may also contain a structure in which structural units represented by the above formulas (6), (7), and / or (8) are repeated.

[0033] More specifically, examples of the structural unit represented by the formula (5) include structural units represented by the following formulas (9) to (11). The structural unit represented by the formula (5) may be one of these alone or a combination of two or more different types. Furthermore, the structural unit may be a structure in which each of the structural units represented by the formulas (9) to (11) below is repeated.

[0034] [ka]

[0035] More specifically, examples of the structural unit represented by the above formula (6) include structural units represented by the following formulas (12) to (18). The structural unit represented by the above formula (6) may be one of these alone or a combination of two or more different types. Furthermore, the structural unit may be a structure in which each of the structural units represented by the following formulas (12) to (18) is repeated.

[0036] [ka]

[0037] [ka]

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] [ka]

[0043] More specifically, examples of the structural unit represented by the formula (7) include structural units represented by the following formulas (19) to (20). The structural unit represented by the formula (7) may be one of these alone or a combination of two or more different types. Furthermore, the structural unit may be a structure in which each of the structural units represented by the formulas (19) to (20) is repeated.

[0044] [ka]

[0045] [ka]

[0046] More specifically, examples of the structural unit represented by the formula (8) include structural units represented by the following formulas (21) to (22). The structural unit represented by the formula (8) may be one of these alone or a combination of two or more different types. Furthermore, the structural unit may be a structure in which each of the structural units represented by the formulas (21) to (22) is repeated.

[0047] [ka]

[0048] [ka]

[0049] Preferred examples of styrene-based block copolymers include copolymers obtained by polymerizing or copolymerizing one or more styrene-based monomers such as styrene, styrene-ethylene, vinyltoluene, α-methylstyrene, isopropenyltoluene, divinylbenzene, allylstyrene, etc. More specific examples 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, styrene (butadiene / butylene)-styrene copolymer, styrene-isobutylene-styrene copolymer, and hydrogenated products thereof.

[0050] As the styrene-based block copolymer, the above-exemplified ones may be used alone or in combination of two or more kinds.

[0051] When the styrene-based block copolymer contains at least one of the structural units represented by the formulas (9) to (11), its mass fraction (i.e., the content of styrene-derived structural units) is preferably about 10 to 60%, more preferably about 20 to 40%, of the entire polymer, which has the advantage of maintaining good compatibility with the radically polymerizable compound and also achieving superior dielectric properties when the resin composition is cured.

[0052] The styrene-based block copolymer of the present embodiment may be a commercially available product, and examples thereof include "Septon V9827" and "Septon 2063" manufactured by Kuraray Co., Ltd., "Tuftec (registered trademark) H1052," "Tuftec (registered trademark) H1041," and "Tuftec (registered trademark) H1221" manufactured by Asahi Kasei Corporation, and "Dynaron 9901P" manufactured by JSR Corporation.

[0053] <Radical polymerizable compound> The radical polymerizable compound used in the present embodiment is not particularly limited as long as it is a compound having radical polymerizability, but it preferably contains a polyphenylene ether compound terminally modified with a substituent having a carbon-carbon unsaturated double bond.

[0054] The polyphenylene ether compound that can be used in this embodiment is preferably a modified polyphenylene ether compound that can exhibit excellent low dielectric properties when cured, and more preferably a polyphenylene ether compound having a group represented by the following formula (4): By containing such a modified polyphenylene ether compound, it is believed that a resin composition can be obtained that can give a cured product with low dielectric properties and high heat resistance.

[0055] [ka] In formula (4), R1 represents a hydrogen atom or an alkyl group. The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0056] Alternatively, the polyphenylene ether compound of the present embodiment may be a polyphenylene ether compound having a group represented by the following formula (23).

[0057] [ka] In formula (23), p represents an integer of 0 to 10. Z represents an arylene group. R1 to R3 are each independent. That is, R 24 ~R 26 may be the same group or different groups. 24 ~R 26 represents a hydrogen atom or an alkyl group.

[0058] In addition, in the formula (23), when p is 0, it means that Z is directly bonded to the end of the polyphenylene ether.

[0059] The arylene group of Z is not particularly limited. Examples of the arylene group include monocyclic aromatic groups such as a phenylene group, and polycyclic aromatic groups in which the aromatic ring is not monocyclic but is polycyclic, such as a naphthalene ring. The arylene group also includes derivatives in which a hydrogen atom bonded to the aromatic ring is substituted with a functional group such as an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. The alkyl group is not particularly limited, and is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0060] Examples of the substituent represented by the formula (4) include an acrylate group and a methacrylate group. Specific examples of preferred substituents represented by the formula (23) include substituents containing a vinylbenzyl group. Examples of the substituents containing a vinylbenzyl group include substituents represented by the following formula (24):

[0061] [ka]

[0062] More specific examples of the substituent include vinylbenzyl groups (ethenylbenzyl groups) such as p-ethenylbenzyl and m-ethenylbenzyl groups, vinylphenyl groups, acrylate groups, and methacrylate groups.

[0063] The polyphenylene ether compound has a polyphenylene ether chain in the molecule, and preferably has, for example, a repeating unit represented by the following formula (25) in the molecule.

[0064] [ka] In formula (25), t represents 1 to 50. 27 ~R 30 are independent of each other. That is, R 27 ~R 30 may be the same group or different groups. 27 ~R 30 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0065] R 27 ~R 30 Specific examples of the functional groups mentioned in the above include the following:

[0066] The alkyl group is not particularly limited, but is preferably an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0067] The alkenyl group is not particularly limited, but is preferably an alkenyl group having 2 to 18 carbon atoms, and more preferably an alkenyl group having 2 to 10 carbon atoms. Specific examples include a vinyl group, an allyl group, and a 3-butenyl group.

[0068] The alkynyl group is not particularly limited, but is preferably an alkynyl group having 2 to 18 carbon atoms, and more preferably an alkynyl group having 2 to 10 carbon atoms. Specific examples include an ethynyl group and a prop-2-yn-1-yl group (propargyl group).

[0069] The alkylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkyl group, but for example, an alkylcarbonyl group having 2 to 18 carbon atoms is preferred, and an alkylcarbonyl group having 2 to 10 carbon atoms is more preferred. Specific examples include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a pivaloyl group, a hexanoyl group, an octanoyl group, and a cyclohexylcarbonyl group.

[0070] The alkenylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkenyl group, but for example, an alkenylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkenylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specific examples include an acryloyl group, a methacryloyl group, and a crotonoyl group.

[0071] The alkynylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkynyl group, but for example, an alkynylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkynylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specific examples include a propioloyl group.

[0072] The weight-average molecular weight (Mw) of the polyphenylene ether compound is not particularly limited. Specifically, it is preferably 500 to 5,000, more preferably 800 to 4,000, and even more preferably 1,000 to 3,000. The weight-average molecular weight may be measured by a general molecular weight measurement method, specifically, a value measured using gel permeation chromatography (GPC), etc. Furthermore, when the polyphenylene ether compound has a repeating unit represented by the formula (25) in the molecule, t is preferably a numerical value such that the weight-average molecular weight of the polyphenylene ether compound falls within this range. Specifically, t is preferably 1 to 50.

[0073] When the weight-average molecular weight of the polyphenylene ether compound is within this range, the compound has the excellent low dielectric properties of polyphenylene ether, and the cured product not only has excellent heat resistance but also has excellent moldability. This is believed to be due to the following reasons. When the weight-average molecular weight of a typical polyphenylene ether is within this range, the compound has a relatively low molecular weight, which tends to reduce the heat resistance of the cured product. In this regard, the polyphenylene ether compound according to this embodiment has one or more unsaturated double bonds at its terminals, which is believed to result in a cured product with sufficiently high heat resistance. Furthermore, when the weight-average molecular weight of the polyphenylene ether compound is within this range, the compound has a relatively low molecular weight, which is believed to result in excellent moldability. Therefore, it is believed that such a polyphenylene ether compound not only has excellent heat resistance but also has excellent moldability.

[0074] The average number of the substituents (number of terminal functional groups) at the molecular terminals per molecule of the polyphenylene ether compound is not particularly limited. Specifically, it is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.5 to 3. If the number of terminal functional groups is too small, it tends to be difficult to obtain a cured product with sufficient heat resistance. On the other hand, if the number of terminal functional groups is too large, the reactivity becomes too high, which may cause problems such as reduced shelf life and reduced fluidity of the resin composition. That is, when such a polyphenylene ether compound is used, insufficient fluidity may cause molding defects such as the generation of voids during multilayer molding, which may lead to moldability problems such as difficulty in obtaining a highly reliable printed wiring board.

[0075] The number of terminal functional groups of a polyphenylene ether compound may be, for example, a numerical value representing the average number of the above-mentioned substituents per molecule of all modified polyphenylene ether compounds present in 1 mole of the polyphenylene ether compound. The number of terminal functional groups can be measured, for example, by measuring the number of hydroxyl groups remaining in the obtained modified polyphenylene ether compound and calculating the difference from the number of hydroxyl groups in the polyphenylene ether before modification. This difference from the number of hydroxyl groups in the polyphenylene ether before modification is the number of terminal functional groups. The number of hydroxyl groups remaining in the modified polyphenylene ether compound can be measured by adding a quaternary ammonium salt (tetraethylammonium hydroxide) that associates with hydroxyl groups to a solution of the modified polyphenylene ether compound and measuring the UV absorbance of the resulting mixed solution.

[0076] The intrinsic viscosity of the polyphenylene ether compound of this embodiment is not particularly limited. Specifically, it may be 0.03 to 0.12 dL / g, preferably 0.04 to 0.11 dL / g, and more preferably 0.06 to 0.095 dL / g. If this intrinsic viscosity is too low, the molecular weight tends to be low, and it tends to be difficult to obtain low dielectric properties such as a low dielectric constant and a low dielectric loss tangent. On the other hand, if the intrinsic viscosity is too high, the viscosity is high, sufficient fluidity cannot be obtained, and the moldability of the cured product tends to be reduced. Therefore, if the intrinsic viscosity of the polyphenylene ether compound is within the above range, excellent heat resistance and moldability of the cured product can be achieved.

[0077] The intrinsic viscosity here is the intrinsic viscosity measured in methylene chloride at 25°C, and more specifically, for example, is the value measured using a viscometer for a 0.18 g / 45 ml methylene chloride solution (liquid temperature: 25°C). Examples of such a viscometer include the AVS500 Visco System manufactured by Schott.

[0078] Examples of the polyphenylene ether compound of the present embodiment include modified polyphenylene ether compounds represented by the following formulas (26) to (28). Furthermore, as the polyphenylene ether compound of the present embodiment, these modified polyphenylene ether compounds may be used alone or in combination.

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] In formulas (26) to (28), R 30 ~R 37 , R 38 ~R 45 and R 46 ~R 49 are independent of each other. That is, R 30 ~R 37 , R 38 ~R 45 and R 46 ~R 49 may be the same group or different groups. 30 ~R 37 , R 38 ~R 45 and R 46 ~R 49 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group.

[0083] In the above formula (28), s represents an integer of 1 to 100.

[0084] R30 ~R 37 , R 38 ~R 45 and R 46 ~R 49 Regarding the above, specific examples of the functional groups include the following:

[0085] The alkyl group is not particularly limited, but is preferably an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0086] The alkenyl group is not particularly limited, but is preferably an alkenyl group having 2 to 18 carbon atoms, and more preferably an alkenyl group having 2 to 10 carbon atoms. Specific examples include a vinyl group, an allyl group, and a 3-butenyl group.

[0087] The alkynyl group is not particularly limited, but is preferably an alkynyl group having 2 to 18 carbon atoms, and more preferably an alkynyl group having 2 to 10 carbon atoms. Specific examples include an ethynyl group and a prop-2-yn-1-yl group (propargyl group).

[0088] The alkylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkyl group, but for example, an alkylcarbonyl group having 2 to 18 carbon atoms is preferred, and an alkylcarbonyl group having 2 to 10 carbon atoms is more preferred. Specific examples include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a pivaloyl group, a hexanoyl group, an octanoyl group, and a cyclohexylcarbonyl group.

[0089] The alkenylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkenyl group, but for example, an alkenylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkenylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specific examples include an acryloyl group, a methacryloyl group, and a crotonoyl group.

[0090] The alkynylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkynyl group, but for example, an alkynylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkynylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specific examples include a propioloyl group.

[0091] In the above formulas (26) and (27), A and B represent repeating units represented by the following formulas (29) and (30), respectively. In the formula (27), Y represents a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms.

[0092] [ka]

[0093] [ka]

[0094] In formula (29) and formula (30), m and n each represent an integer of 0 to 20. Preferably, m and n represent a numerical value such that the sum of m and n is 1 to 30. Therefore, it is more preferable that m represents an integer of 0 to 20, n represents an integer of 0 to 20, and the sum of m and n represents an integer of 1 to 30.

[0095] In addition, in formulas (29) and (30), R 50 ~R 53 and R 54 ~R 57 are independent of each other, and R 50 ~R 53 and R 54 ~R 57 may be the same or different groups and represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group.

[0096] In the formula (27), Y is, as described above, a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms. Examples of Y include a group represented by the following formula (31).

[0097] [ka] In the formula (31), R 58 and R 59 are each independently a hydrogen atom or an alkyl group. Examples of the alkyl group include a methyl group. Examples of the group represented by formula (31) include a methylene group, a methylmethylene group, and a dimethylmethylene group, and among these, a dimethylmethylene group is preferred.

[0098] In the formulas (26) to (28), X1 to X3 each independently represent, for example, a substituent represented by the formula (4) and / or a substituent represented by the formula (23). In the modified polyphenylene ether compounds represented by the formulas (26) to (28), X1 to X3 may be the same or different substituents.

[0099] More specific examples of the modified polyphenylene ether compound represented by the formula (26) include modified polyphenylene ether compounds represented by the following formula (32).

[0100] [ka]

[0101] More specific examples of the modified polyphenylene ether compound represented by the formula (26) include a modified polyphenylene ether compound represented by the following formula (33) and a modified polyphenylene ether compound represented by the following formula (34).

[0102] [ka]

[0103] [ka]

[0104] In the formulas (32) to (34), m and n have the same meanings as m and n in the formulas (29) and (30). 24 ~R 26 , p and Z are R in the above formula (23), respectively. 24 ~R 26 , p and Z. In addition, in the above formulas (33) and (34), Y is the same as Y in the above formula (27). In addition, in the above formula (34), R1 is the same as R1 in the above formula (4). From the viewpoint of more reliably obtaining a high Tg, it is preferable that the modified polyphenylene ether compounds represented by the formulas (32) to (34) have a group represented by the above formula (4) at their terminals.

[0105] Examples of a method for synthesizing the polyphenylene ether compound used in the present embodiment include a method for synthesizing a polyphenylene ether compound terminally modified with a group represented by the formula (4) and / or the formula (23). More specifically, examples include a method for reacting a polyphenylene ether with a compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded.

[0106] Examples of compounds in which a substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom include compounds in which a substituent represented by the formulas (4), (23), and (24) is bonded to a halogen atom. Specific examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom, with a chlorine atom being preferred. More specific examples of compounds in which a substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom include p-chloromethylstyrene and m-chloromethylstyrene.

[0107] The polyphenylene ether used as the raw material is not particularly limited as long as it can ultimately synthesize a predetermined modified polyphenylene ether compound. Specific examples include polyphenylene ethers composed of 2,6-dimethylphenol and at least one of a bifunctional phenol and a trifunctional phenol, and those containing polyphenylene ether as the main component, such as poly(2,6-dimethyl-1,4-phenylene oxide). Furthermore, a bifunctional phenol is a phenolic compound having two phenolic hydroxyl groups per molecule, such as tetramethylbisphenol A. Furthermore, a trifunctional phenol is a phenolic compound having three phenolic hydroxyl groups per molecule.

[0108] The polyphenylene ether compound of this embodiment can be synthesized by the method described above. Specifically, the polyphenylene ether described above and a compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded are dissolved in a solvent and stirred. By doing so, the polyphenylene ether reacts with the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, thereby obtaining the polyphenylene ether compound used in this embodiment.

[0109] The reaction is preferably carried out in the presence of an alkali metal hydroxide. It is believed that this allows the reaction to proceed smoothly. This is believed to be because the alkali metal hydroxide functions as a dehydrohalogenating agent, specifically, a dehydrochlorinating agent. That is, it is believed that the alkali metal hydroxide eliminates hydrogen halide from the phenol group of the polyphenylene ether and a compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and as a result, the substituent having a carbon-carbon unsaturated double bond is bonded to the oxygen atom of the phenol group in place of the hydrogen atom of the phenol group of the polyphenylene ether.

[0110] The alkali metal hydroxide is not particularly limited as long as it can act as a dehalogenating agent, and examples thereof include sodium hydroxide, etc. The alkali metal hydroxide is usually used in the form of an aqueous solution, specifically, an aqueous sodium hydroxide solution.

[0111] Reaction conditions such as reaction time and reaction temperature vary depending on the compound in which a substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom, and are not particularly limited as long as the conditions are such that the above-mentioned reaction proceeds favorably. Specifically, the reaction temperature is preferably room temperature to 100°C, more preferably 30 to 100°C. The reaction time is preferably 0.5 to 20 hours, more preferably 0.5 to 10 hours.

[0112] The solvent used in the reaction is not particularly limited as long as it can dissolve the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and does not inhibit the reaction between the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded. Specific examples include toluene.

[0113] The above reaction is preferably carried out in the presence of not only an alkali metal hydroxide but also a phase transfer catalyst. That is, the above reaction is preferably carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst. Doing so is believed to allow the reaction to proceed more smoothly. This is believed to be due to the following: A phase transfer catalyst has the function of incorporating an alkali metal hydroxide, is soluble in both a polar solvent phase such as water and a nonpolar solvent phase such as an organic solvent, and is capable of transferring between these phases. Specifically, when an aqueous solution of sodium hydroxide is used as the alkali metal hydroxide and an organic solvent such as toluene, which is incompatible with water, is used as the solvent, even if the aqueous solution of sodium hydroxide is added dropwise to the solvent being used for the reaction, the solvent and the aqueous solution of sodium hydroxide separate, and it is believed that the sodium hydroxide is unlikely to migrate to the solvent. In this case, it is believed that the aqueous solution of sodium hydroxide added as the alkali metal hydroxide is unlikely to contribute to promoting the reaction. On the other hand, when the reaction is carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst, the alkali metal hydroxide is transferred to the solvent while being incorporated into the phase transfer catalyst, and the aqueous sodium hydroxide solution is thought to contribute more to promoting the reaction. Therefore, when the reaction is carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst, the reaction is thought to proceed more smoothly.

[0114] The phase transfer catalyst is not particularly limited, but examples thereof include quaternary ammonium salts such as tetra-n-butylammonium bromide.

[0115] The resin composition used in this embodiment preferably contains the modified polyphenylene ether compound obtained as described above as the radical polymerizable compound.

[0116] The resin composition according to this embodiment may also contain the following compounds as examples of the radical polymerizable compound.

[0117] Specific examples include compounds having an acryloyl group in the molecule, compounds having a methacryloyl group in the molecule, compounds having a vinyl group in the molecule, compounds having an allyl group in the molecule, compounds having an acenaphthylene structure in the molecule, compounds having a maleimide group in the molecule, and isocyanurate compounds having an isocyanurate group in the molecule.

[0118] The compound having an acryloyl group in the molecule is an acrylate compound. Examples of the acrylate compound include monofunctional acrylate compounds having one acryloyl group in the molecule and polyfunctional acrylate compounds having two or more acryloyl groups in the molecule. Examples of the monofunctional acrylate compound include methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. Examples of the polyfunctional acrylate compound include diacrylate compounds such as tricyclodecane dimethanol diacrylate.

[0119] The compound having a methacryloyl group in the molecule is a methacrylate compound. Examples of the methacrylate compound include monofunctional methacrylate compounds having one methacryloyl group in the molecule and polyfunctional methacrylate compounds having two or more methacryloyl groups in the molecule. Examples of the monofunctional methacrylate compound include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Examples of the polyfunctional methacrylate compound include dimethacrylate compounds such as tricyclodecane dimethanol dimethacrylate, and trimethacrylate compounds such as trimethylolpropane trimethacrylate.

[0120] The compound having a vinyl group in the molecule is a vinyl compound. Examples of the vinyl compound include a monofunctional vinyl compound (monovinyl compound) having one vinyl group in the molecule, and a polyfunctional vinyl compound having two or more vinyl groups in the molecule. Examples of the polyfunctional vinyl compound include divinylbenzene and polybutadiene.

[0121] The compound having an allyl group in the molecule is an allyl compound. Examples of the allyl compound include monofunctional allyl compounds having one allyl group in the molecule and polyfunctional allyl compounds having two or more allyl groups in the molecule. Examples of the polyfunctional allyl compound include triallyl isocyanurate compounds such as triallyl isocyanurate (TAIC), diallyl bisphenol compounds, and diallyl phthalate (DAP).

[0122] The compound having an acenaphthylene structure in the molecule is an acenaphthylene compound. Examples of the acenaphthylene compound include acenaphthylene, alkylacenaphthylenes, halogenated acenaphthylenes, and phenylacenaphthylenes. Examples of the alkylacenaphthylenes include 1-methylacenaphthylene, 3-methylacenaphthylene, 4-methylacenaphthylene, 5-methylacenaphthylene, 1-ethylacenaphthylene, 3-ethylacenaphthylene, 4-ethylacenaphthylene, and 5-ethylacenaphthylene. Examples of the halogenated acenaphthylenes include 1-chloroacenaphthylene, 3-chloroacenaphthylene, 4-chloroacenaphthylene, 5-chloroacenaphthylene, 1-bromoacenaphthylene, 3-bromoacenaphthylene, 4-bromoacenaphthylene, and 5-bromoacenaphthylene. Examples of the phenylacenaphthylenes include 1-phenylacenaphthylene, 3-phenylacenaphthylene, 4-phenylacenaphthylene, and 5-phenylacenaphthylene. The acenaphthylene compound may be a monofunctional acenaphthylene compound having one acenaphthylene structure in the molecule, as described above, or a polyfunctional acenaphthylene compound having two or more acenaphthylene structures in the molecule.

[0123] The compound having a maleimide group in the molecule is a maleimide compound. Examples of the maleimide compound include a monofunctional maleimide compound having one maleimide group in the molecule, a polyfunctional maleimide compound having two or more maleimide groups in the molecule, and a modified maleimide compound. Examples of the modified maleimide compound include a modified maleimide compound in which a portion of the molecule is modified with an amine compound, a modified maleimide compound in which a portion of the molecule is modified with a silicone compound, and a modified maleimide compound in which a portion of the molecule is modified with an amine compound and a silicone compound.

[0124] The compound having an isocyanurate group in the molecule is an isocyanurate compound. Examples of the isocyanurate compound include compounds further having an alkenyl group in the molecule (alkenyl isocyanurate compounds), such as triallyl isocyanurate (TAIC).

[0125] Among these, suitable examples of radical polymerizable compounds other than the above-mentioned modified polyphenylene ether compounds include allyl compounds, vinyl compounds, maleimide compounds, and the like.

[0126] The above radical polymerizable compounds may be used alone or in combination of two or more kinds.

[0127] When two or more types are combined, it is preferable to use one or more of the above-mentioned terminally modified polyphenylene ether compounds and, for example, an allyl compound having an allyl group in the molecule, as described above. As the allyl compound, an allyl isocyanurate compound having two or more allyl groups in the molecule is preferred, and triallyl isocyanurate (TAIC) is more preferred. This has the advantage that when the terminally modified polyphenylene ether and triallyl isocyanurate undergo a radical reaction, the resulting cured resin exhibits high heat resistance.

[0128] (free radical compounds) The free radical compound used in this embodiment contains at least one selected from the group consisting of a compound (A) represented by the following formula (1), a compound (B) represented by the following formula (2), and a compound (C) having two or more groups each selected from the group represented by the following formula (3-1) and formula (3-2). By containing such a free radical compound, the resin composition of this embodiment is thought to be able to exhibit excellent moldability (resin flowability capable of filling a circuit pattern, i.e., circuit filling ability) while maintaining properties such as low dielectric properties and a high Tg.

[0129] [ka]

[0130] [ka]

[0131] [ka]

[0132] [ka]

[0133] In the formula (1) and the formula (2), X A and X B each independently represents a hydrogen atom, an amino group, a cyano group, a hydroxy group, an isothiocyanate group, a methoxy group, a carboxy group, a carbonyl group, an amido group, or a benzoyloxy group.

[0134] The compound (C) having two or more groups selected from the groups represented by formula (3-1) and formula (3-2) is not particularly limited, and may be a compound having both groups represented by formula (3-1) and formula (3-2), a compound having two or more groups represented by formula (3-1), or a compound having two or more groups represented by formula (3-2). Specific examples include compounds represented by the following formula (3-3).

[0135] [ka] In formula (3-3), X C represents an alkylene group, an aromatic structure, a carbonyl group, an amide group, or an ether bond.

[0136] More specific examples of these include 4-acetamido, 4-glycidyloxy, 4-benzoyloxy, 4-(2-iodoacetamido), 4-[2-[2-(4-iodophenoxy)ethoxy]carbonyl]benzoyloxy, 4-methacryloyloxy, 4-oxo, and 4-propargyloxy.

[0137] More specific free radical compounds preferably used in this embodiment include 4-amino-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-carboxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-cyano-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-glycidyloxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxylbenzoate free radical, and 4-isothiocyanato-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-(2-iodoacetamido)-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-[2-[2-(4-iodophenoxy)ethoxy]carbonyl]benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl Free radical, 4-methoxy-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 4-oxo-2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 2,2,6,6-tetramethylpiperidine 1-oxyl Free radical, 2,2,6,6-tetramethyl-4-(2-propynyloxy)piperidine 1-oxyl free radical, bis(2,2,6,6-tetramethyl-4-piperidyl-1-oxyl) sebacate, 3-carboxy-2,2,5,5-tetramethylpyrrolidine 1-oxyl free radical, 4-(2-chloroacetamido)-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, and the like.

[0138] Various free radical compounds have been mentioned above, and these may be used alone or in combination of two or more.

[0139] The free radical compound of this embodiment as described above may be commercially available and is available from, for example, Tokyo Chemical Industry Co., Ltd.

[0140] (inorganic filler) The resin composition according to the present embodiment may further contain an inorganic filler. Examples of inorganic fillers include those added to enhance the heat resistance and flame retardancy of the cured product of the resin composition, and are not particularly limited. It is believed that the inclusion of an inorganic filler can further enhance the heat resistance and flame retardancy, and also suppress an increase in the coefficient of thermal expansion.

[0141] Specific examples of inorganic fillers that can be used in this embodiment include silica such as spherical silica, metal oxides such as alumina, titanium oxide, and mica, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, talc, aluminum borate, barium sulfate, and calcium carbonate. Among these, silica, mica, and talc are preferred, and spherical silica is more preferred. The inorganic fillers may be used alone or in combination of two or more. The inorganic fillers described above may be used as is, or may be surface-treated with an epoxysilane-type, vinylsilane-type, methacrylsilane-type, or phenylaminosilane-type silane coupling agent. This silane coupling agent can be added to the filler by integral blending rather than by surface-treating the filler in advance.

[0142] (Reaction initiator) As described above, the resin composition according to this embodiment may contain a reaction initiator (initiator). The curing reaction of the resin composition may proceed even without the inclusion of a reaction initiator. However, depending on the process conditions, it may be difficult to raise the temperature high enough for curing to proceed, so a reaction initiator may be added.

[0143] The reaction initiator is not particularly limited as long as it can accelerate the curing reaction of the resin composition, and specific examples thereof include metal oxides, azo compounds, and peroxides.

[0144] Specific examples of metal oxides include metal carboxylates.

[0145] Examples of peroxides include α,α'-di(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, benzoyl peroxide, 3,3',5,5'-tetramethyl-1,4-diphenoquinone, chloranil, 2,4,6-tri-t-butylphenoxyl, t-butylperoxyisopropyl monocarbonate, and azobisisobutyronitrile.

[0146] Specific examples of the azo compound include 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(N-butyl-2-methylpropionamide), and 2,2'-azobis(2-methylbutyronitrile).

[0147] Among these, α,α'-di(t-butylperoxy)diisopropylbenzene is preferably used as a preferred reaction initiator. α,α'-Di(t-butylperoxy)diisopropylbenzene has low volatility and therefore does not volatilize during drying or storage, resulting in good stability. Furthermore, α,α'-di(t-butylperoxy)diisopropylbenzene has a relatively high reaction initiation temperature, which can suppress the promotion of the curing reaction when curing is not required, such as during prepreg drying. This suppression of the curing reaction can prevent a decrease in the shelf life of the resin composition.

[0148] The above-mentioned reaction initiators may be used alone or in combination of two or more kinds.

[0149] (Content of each ingredient) The content of the free radical compound is preferably 0.001 to 1 part by mass, more preferably 0.001 to 0.5 parts by mass, and even more preferably 0.001 to 0.2 parts by mass, relative to 100 parts by mass of the total of the styrene-based block copolymer and the radically polymerizable compound in the resin composition. When the content of the free radical compound is within the above range, it is believed that a cured product having low dielectric properties, a high Tg, and a low coefficient of thermal expansion can be obtained, and a resin composition having excellent moldability can be more reliably obtained.

[0150] The content of the styrene-based block copolymer is preferably 10 to 60 parts by mass, more preferably 15 to 50 parts by mass, and even more preferably 20 to 40 parts by mass, relative to 100 parts by mass of the resin component (organic component) in the resin composition. That is, the content of the styrene-based block copolymer is preferably 10 to 60% by mass relative to the components other than the inorganic filler (inorganic component) in the resin composition.

[0151] The content of the radical polymerizable compound is preferably 30 to 90 parts by mass, more preferably 40 to 80 parts by mass, and even more preferably 50 to 70 parts by mass, relative to 100 parts by mass of the resin component (organic component) in the resin composition. That is, the content of the radical polymerizable compound is preferably 30 to 90% by mass relative to the components other than the inorganic filler (inorganic component) in the resin composition.

[0152] In particular, when the resin composition contains a radically polymerizable compound (modified polyphenylene ether compound) according to a preferred embodiment, the content of the radically polymerizable compound is preferably 10 to 50 parts by mass, more preferably 20 to 50 parts by mass, and even more preferably 30 to 40 parts by mass, per 100 parts by mass of the resin component (organic component) in the resin composition.

[0153] Furthermore, when the radical polymerizable compound contains a radical polymerizable compound other than the above (such as an allyl compound), the content of the other radical polymerizable compound is preferably 10 to 50 parts by mass, and more preferably 20 to 40 parts by mass, per 100 parts by mass of the resin component (organic component) in the resin composition.

[0154] When the resin composition of this embodiment contains the reaction initiator, its content is not particularly limited, but is preferably 0.01 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, and even more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the resin component (organic component) in the resin composition. If the content of the reaction initiator is too low, the curing reaction of the resin composition tends not to start properly. On the other hand, if the content of the initiator is too high, the dielectric loss tangent of the cured product of the obtained prepreg tends to increase, making it difficult to exhibit excellent low dielectric properties. Therefore, if the content of the reaction initiator is within the above range, a cured prepreg with excellent low dielectric properties can be obtained.

[0155] When the resin composition of this embodiment contains the reaction initiator, the ratio of the free radical compound to the reaction initiator in the resin composition (free radical compound: reaction initiator) is preferably about 0.001:1.0 to 0.1:1.0, more preferably about 0.005:1.0 to 0.1:1.0, and even more preferably about 0.01:1.0 to 0.1:1.0. This is believed to more reliably achieve the effects of the present invention.

[0156] Furthermore, when the resin composition of the present embodiment contains an inorganic filler, the content thereof (filler content) is preferably 30 to 300 mass %, more preferably 50 to 200 mass %, based on the total mass of the resin composition.

[0157] <Other ingredients> The resin composition according to the present embodiment may contain other components (other components) in addition to the components described above, as necessary, as long as the effects of the present invention are not impaired. Examples of other components contained in the resin composition according to the present embodiment include additives such as curing agents, silane coupling agents, flame retardants, antifoaming agents, antioxidants, heat stabilizers, antistatic agents, UV absorbers, dyes and pigments, dispersants, and lubricants. Furthermore, the resin composition according to the present embodiment may contain, in addition to the polyphenylene ether compound, the allyl compound, and the styrene-based block copolymer, other thermosetting resins such as epoxy resins and phenolic resins.

[0158] (Prepreg, resin-coated film, metal-clad laminate, wiring board, and resin-coated metal foil) Next, a prepreg for a wiring board, a metal-clad laminate, a wiring board, and a resin-coated metal foil using the resin composition of this embodiment will be described.

[0159] 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to an embodiment of the present invention. In the following description, the reference numerals respectively represent 1 prepreg, 2 resin composition or semi-cured resin composition, 3 fibrous base material, 11 metal-clad laminate, 12 insulating layer, 13 metal foil, 14 wiring, 21 wiring board, 31 resin-coated metal foil, 32 and 42 resin layer, 41 resin-coated film, and 43 support film.

[0160] As shown in Fig. 1, the prepreg 1 according to this embodiment comprises the resin composition containing the thermally expandable microcapsules or a semi-cured product of the resin composition 2, and a fibrous base material 3. Examples of this prepreg 1 include those in which the fibrous base material 3 is present in the resin composition or semi-cured product 2. That is, this prepreg 1 comprises the resin composition or semi-cured product thereof, and the fibrous base material 3 present in the resin composition or semi-cured product 2.

[0161] In this embodiment, the term "semi-cured product" refers to a resin composition that has been partially cured to the extent that it can be further cured. That is, the semi-cured product is a resin composition that has been semi-cured (B-staged). For example, when a resin composition is heated, the viscosity initially gradually decreases, and then curing begins, and the viscosity gradually increases. In such a case, the semi-cured state can be exemplified by the state between when the viscosity starts to increase and when the composition is completely cured.

[0162] The prepreg obtained using the resin composition according to this embodiment may comprise a semi-cured product of the resin composition as described above, or may comprise the uncured resin composition itself. That is, it may be a prepreg comprising a semi-cured product of the resin composition (the resin composition in B stage) and a fibrous substrate, or a prepreg comprising the resin composition before curing (the resin composition in A stage) and a fibrous substrate. Specific examples include those in which a fibrous substrate is present in the resin composition. The resin composition or a semi-cured product thereof may be obtained by heating and drying the resin composition.

[0163] The resin composition according to the present embodiment is often prepared in the form of a varnish and used as a resin varnish when producing the prepreg, or the resin-coated metal foil or metal-clad laminate described below. Such a resin varnish is prepared, for example, as follows.

[0164] First, components soluble in organic solvents, such as resin components and reaction initiators, are added to an organic solvent and dissolved. Heating may be performed as necessary. Subsequently, inorganic fillers and other components insoluble in organic solvents are added and dispersed using a ball mill, bead mill, planetary mixer, roll mill, or the like until a predetermined dispersion state is achieved, thereby preparing a varnish-like resin composition. The organic solvent used here is not particularly limited as long as it dissolves the styrene-based block copolymer, the radically polymerizable compound, and the like and does not inhibit the curing reaction. Specific examples include toluene, methyl ethyl ketone, cyclohexanone, and propylene glycol monomethyl ether acetate. These may be used alone or in combination of two or more.

[0165] An example of a method for producing the prepreg 1 of this embodiment using the varnish-like resin composition of this embodiment is a method in which the fibrous base material 3 is impregnated with the resin composition 2 in the form of a resin varnish, and then dried.

[0166] Specific examples of fibrous substrates used in producing prepregs 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. The use of glass cloth results in a laminate with excellent mechanical strength, and flattened glass cloth is particularly preferred. The glass cloth used in this embodiment is not particularly limited, but examples include low-dielectric-constant glass cloths such as E glass, S glass, NE glass, Q glass, L glass, L2 glass, and T glass. Flattening can be performed, for example, by continuously pressing the glass cloth with a press roll at an appropriate pressure to compress the yarns flat. The thickness of the fibrous substrate can generally be, for example, 0.01 to 0.3 mm.

[0167] The resin varnish (resin composition 2) is impregnated into the fibrous substrate 3 by immersion, coating, or the like. This impregnation can be repeated multiple times as necessary. In this case, it is also possible to repeat the impregnation using multiple resin varnishes with different compositions and concentrations, and to adjust the final composition (content ratio) and resin amount to the desired one.

[0168] The fibrous substrate 3 impregnated with the resin varnish (resin composition 2) is heated under desired heating conditions, for example, at a temperature of 80°C or higher and 180°C or lower for 1 minute or longer and 10 minutes or shorter. By heating, the solvent is volatilized from the varnish, reducing or removing the solvent, and a prepreg 1 in an uncured (A-stage) or semi-cured (B-stage) state is obtained.

[0169] 4, the resin-coated metal foil 31 of this embodiment has a configuration in which a resin layer 32 containing the above-mentioned resin composition or a semi-cured product of the resin composition is laminated with a metal foil 13. That is, the resin-coated metal foil of this embodiment may be a resin-coated metal foil comprising a resin layer containing the resin composition before curing (the resin composition in A stage) and a metal foil, or a resin-coated metal foil comprising a resin layer containing a semi-cured product of the resin composition (the resin composition in B stage) and a metal foil.

[0170] An example of a method for producing such a resin-coated metal foil 31 is a method in which the resin composition in the form of a resin varnish as described above is applied to the surface of a metal foil 13 such as a copper foil, followed by drying. Examples of the application method include a bar coater, a comma coater, a die coater, a roll coater, a gravure coater, and the like.

[0171] As the metal foil 13, any metal foil that is used in metal-clad laminates, wiring boards, etc. can be used without any limitation, and examples thereof include copper foil and aluminum foil.

[0172] 5, a resin-coated film 41 of this embodiment has a configuration in which a resin layer 42 containing the above-mentioned resin composition or a semi-cured product of the resin composition is laminated on a film support substrate 43. That is, the resin-coated film of this embodiment may be a resin-coated film comprising the resin composition before curing (the resin composition in A stage) and a film support substrate, or may be a resin-coated film comprising a semi-cured product of the resin composition (the resin composition in B stage) and a film support substrate.

[0173] A method for producing such a resin-coated film 41 is, for example, to apply a resin composition in the form of a resin varnish as described above to the surface of the film support substrate 43, and then evaporate the solvent from the varnish to reduce or remove the solvent, thereby obtaining a resin-coated film in a pre-cured (A stage) or semi-cured (B stage) state.

[0174] Examples of the film support substrate 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.

[0175] In the resin-coated film and resin-coated metal foil of this embodiment, the resin composition or a semi-cured product thereof may be obtained by drying or heat-drying the resin composition, as in the case of the prepreg described above.

[0176] The thickness of the metal foil 13 and the film support substrate 43 can be appropriately set depending on the desired purpose. For example, a metal foil 13 having a thickness of about 0.2 to 70 μm can be used. When the thickness of the metal foil is, for example, 10 μm or less, a carrier-attached copper foil having a release layer and a carrier for improved handleability may be used. The resin varnish is applied to the metal foil 13 and the film support substrate 43 by coating or the like, which can be repeated multiple times as necessary. In this case, it is also possible to repeatedly apply multiple resin varnishes with different compositions and concentrations to adjust the final composition (content ratio) and resin amount to the desired one.

[0177] There are no particular limitations on the drying or heating drying conditions in the manufacturing method of the resin-coated metal foil 31 or the resin film 41, but after applying a resin varnish-like resin composition to the above-mentioned metal foil 13 or film support substrate 43, it is heated under the desired heating conditions, for example, at 50 to 170°C for about 0.5 to 10 minutes, to volatilize the solvent from the varnish and reduce or remove the solvent, thereby obtaining the resin-coated metal foil 31 or resin film 41 in an uncured (A stage) or semi-cured (B stage) state.

[0178] The resin-coated metal foil 31 and the resin film 41 may be provided with a cover film or the like as necessary. The provision of a cover film can prevent the inclusion of foreign matter, etc. The cover film is not particularly limited as long as it can be peeled off without damaging the shape of the resin composition. For example, a polyolefin film, a polyester film, a TPX film, a film formed by providing a release agent layer on any of these films, or even paper formed by laminating any of these films onto a paper substrate can be used.

[0179] 2, the metal-clad laminate 11 of this embodiment is characterized by having an insulating layer 12 containing a cured product of the above-mentioned resin composition or a cured product of the above-mentioned prepreg, and a metal foil 13. Note that the metal foil 13 used in the metal-clad laminate 11 may be the same as the metal foil 13 described above.

[0180] The metal-clad laminate 11 of this embodiment can also be produced using the resin-coated metal foil 31 or resin film 41 described above.

[0181] A method for producing a metal-clad laminate using the prepreg 1, resin-coated metal foil 31, or resin film 41 obtained as described above involves stacking one or more prepregs 1, resin-coated metal foil 31, or resin film 41, and then stacking a metal foil 13 such as copper foil on either or both sides of the prepreg 1, and then heat-pressure molding the stack to form an integrated laminate, thereby producing a double-sided or single-sided metal foil-clad laminate. The heat-pressure conditions can be appropriately set depending on the thickness of the laminate to be produced, the type of resin composition, and other factors, but can be, for example, a temperature of 170 to 230°C, a pressure of 0.5 to 5.0 MPa, and a time of 60 to 150 minutes.

[0182] Alternatively, the metal-clad laminate 11 may be produced by forming a film-like resin composition on the metal foil 13 and applying heat and pressure, without using the prepreg 1 or the like.

[0183] As shown in FIG. 3, wiring board 21 of this embodiment has insulating layer 12 containing a cured product of the above-mentioned resin composition or a cured product of the above-mentioned prepreg, and wiring 14.

[0184] The resin composition of this embodiment is suitable for use as a material for an insulating layer of a wiring board. For example, a method for producing a wiring board 21 is to form a circuit (wiring) by etching the metal foil 13 on the surface of the metal clad laminate 13 obtained above, thereby obtaining a wiring board 21 having a conductor pattern (wiring 14) provided as a circuit on the surface of the laminate. Examples of the method for forming a circuit include, in addition to the above-described methods, circuit formation by a semi-additive process (SAP) or a modified semi-additive process (MSAP).

[0185] The prepreg, resin-coated film, and resin-coated metal foil obtained using the resin composition of this embodiment have low dielectric properties, a low coefficient of thermal expansion, a high Tg, and excellent moldability (circuit filling ability) when cured, making them very useful for industrial applications. Furthermore, the metal-clad laminates and wiring boards obtained by curing them have the advantages of low dielectric properties, a high Tg, and excellent handleability.

[0186] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples. [Example]

[0187] First, the components used in preparing the resin composition in this example will be described.

[0188] (styrene-based block copolymer) Styrene-based block copolymer 1: Styrene-isoprene-styrene copolymer (Septon 2063 manufactured by Kuraray Co., Ltd., durometer hardness: 36, content of styrene-derived structural units: 13% by mass, weight-average molecular weight: 95,000) Styrene-based block copolymer 2: Hydrogenated styrene (ethylene / butylene) styrene copolymer (Tuftec H1052 manufactured by Asahi Kasei Corporation, durometer hardness: 67, content of styrene-derived structural units: 20% by mass, weight-average molecular weight: 91,000) Styrene-based block copolymer 3: Hydrogenated methylstyrene (ethylene / butylene) methylstyrene copolymer (Septon V9827 manufactured by Kuraray Co., Ltd., durometer hardness: 78, content of styrene-derived structural units: 30% by mass, weight-average molecular weight: 92,000) Styrene-based block copolymer 4: Hydrogenated styrene (ethylene / butylene) styrene copolymer (Dynaron 9901P manufactured by JSR Corporation, durometer hardness: 98, content of styrene-derived structural units: 53% by mass, weight-average molecular weight: 100,000)

[0189] (Radical polymerizable compound: polyphenylene ether compound) PPE1: modified polyphenylene ether in which the terminal hydroxyl group of polyphenylene ether is modified with a methacryloyl group (represented by the above formula (34), in which Y in formula (34) is a dimethylmethylene group (represented by formula (31), in which R 58 and R 59 modified polyphenylene ether compound (wherein each methyl group is a group), SA9000 manufactured by SABIC Innovative Plastics, weight average molecular weight Mw 2000, number of terminal functional groups 2) PPE2: a polyphenylene ether compound having a vinylbenzyl group (ethenylbenzyl group) at the end (OPE-2st 1200, Mn1200 manufactured by Mitsubishi Gas Chemical Company, Inc., represented by the above formula (32) in which Z is a phenylene group and R 24 ~R 26 is a hydrogen atom and p is 1)

[0190] (Radical polymerizable compound: allyl compound) TAIC: Triallyl isocyanurate (manufactured by Nippon Kasei Co., Ltd.)

[0191] (free radical compounds) Free radical compound 1: 4-benzoyloxytempo, a free radical compound represented by the following formula (Tokyo Chemical Industry Co., Ltd. "H0878")

[0192] [ka]

[0193] Free radical compound 2: bis-tempo sebacic acid, a free radical compound represented by the following formula ("B5642" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0194] [ka]

[0195] Free radical compound 3: tempo, a free radical compound represented by the following formula ("T3751" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0196] [ka]

[0197] Free radical compound 4: 4H-tempo, a free radical compound represented by the following formula (Tokyo Chemical Industry Co., Ltd. "H0865")

[0198] [ka]

[0199] (polymerization inhibitor) Hydroquinone HQ: Hydroquinone (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0200] (Reaction initiator) Peroxide: "Perbutyl P", 1,3-bis(butylperoxyisopropyl)benzene (manufactured by NOF Corporation)

[0201] (inorganic filler) Silica particles: "SC2300-SVJ" vinylsilane-treated spherical silica (manufactured by Admatechs Co., Ltd.)

[0202] <Examples 1 to 13 and Comparative Examples 1 to 3> [Preparation method] (resin varnish) First, the above components except for the inorganic filler were added to toluene and mixed in the composition (parts by mass) shown in Table 1 so that the solids concentration was 50 mass%. The mixture was stirred for 60 minutes. Thereafter, the inorganic filler was added to the resulting liquid, and the filler was dispersed using a bead mill. This resulted in a varnish-like resin composition (varnish).

[0203] (Metal foil with resin and evaluation board) Resin-coated metal foils were produced using the resin varnishes of each of the Examples and Comparative Examples prepared above. The resulting varnish was applied to a metal foil (copper foil, 3EC-VLP manufactured by Mitsui Mining & Smelting Co., Ltd., thickness 12 μm) to a thickness of 20 μm, and heated at 80°C for 2 minutes to obtain a resin-coated metal foil. Two of the resulting resin-coated metal foils were then stacked so that the resin layers were in contact with each other. This was used as a pressure body, and heated and pressurized under vacuum at 200°C and a pressure of 4 MPa for 2 hours to cure the resin layer of the resin-coated metal foil. This was used as an evaluation substrate (cured resin-coated metal foil). The thickness of the resin layer (thickness excluding the metal foil) in the evaluation substrate was 40 μm.

[0204] <Evaluation test> (glass transition temperature (Tg)) The copper foil of the evaluation substrate (the cured resin-coated metal foil) was removed from the laminate, and Tg was measured using a viscoelasticity spectrometer "DMS100" manufactured by Seiko Instruments Inc. Dynamic viscoelasticity measurement (DMA) was performed using a tensile module at a frequency of 10 Hz, and the temperature at which tan δ reached a maximum when the temperature was raised from room temperature to 320°C at a heating rate of 5°C / min was defined as Tg. In this example, Tg was evaluated as ⊚ if it was 230°C or higher, ◯ if it was 200°C or higher, and × if it was less than 200°C.

[0205] (Dielectric properties: relative permittivity (Dk)) The dielectric constant of the laminate from which the copper foil of the evaluation substrate (cured resin-coated metal foil) was removed was measured at 10 GHz using a cavity resonator perturbation method. Specifically, a network analyzer (Agilent Technologies N5230A) was used to measure the dielectric constant (Dk) of the laminate from which the copper foil of the evaluation substrate was removed at 10 GHz. In this example, Dk was evaluated as ⊚ if it was 2.6 or less, ◯ if it was 2.7 or less, and × if it was over 2.7.

[0206] Coefficient of Linear Expansion (CTE) The copper foil of the evaluation substrate (the cured resin-coated metal foil) was removed and the linear expansion coefficient in the in-plane direction of the laminate was measured in tensile mode using a method conforming to JIS C 6481. The measurement conditions were a heating rate of 10°C / min and a temperature range below Tg, specifically, 50 to 100°C, using a thermomechanical analyzer (TMA / SS7000 manufactured by Hitachi High-Tech Science Corporation). In this example, a CTE of 30 ppm or less was evaluated as ⊚, a CTE of 40 ppm or less was evaluated as ◯, and a CTE of more than 40 ppm was evaluated as ×.

[0207] (Moldability: circuit filling property) A 250mm x 250mm cured product was prepared with a grid-like copper pattern, with a copper residual ratio of 50%, a copper wire thickness of 12μm, and a copper wire width of 2μm. 250mm x 250mm resin-coated metal foil was placed on both sides so that the resin surface was in contact with the cured product. These were sandwiched between metal plates approximately 3mm thick and heated and pressurized using a laminate molding press under the following conditions. The heating was performed at a rate of 6°C per minute from 30°C to 200°C. The pressure applied to the resin-coated metal foil was set to 1MPa at the start of heating, and then increased to 4MPa when the temperature reached 80°C, allowing the resin-coated metal foil to cure.

[0208] In this example, cases where no gaps were generated between the lattice pattern and the cured resin and the resin was filled in were evaluated as "Good", and cases where gaps were generated were evaluated as "Poor." The presence or absence of gaps was determined by removing the copper foil from the cured product produced using a laminate molding press and shining light through the other side, and checking whether whitish gaps could be confirmed.

[0209] The results are shown in Table 1.

[0210] [Table 1]

[0211] (Consideration) As is clear from the results shown in Table 1, it was confirmed that the resin composition of the present invention can provide a cured product that has a good balance of low dielectric properties, low CTE, and high Tg, as well as excellent circuit filling properties.

[0212] In contrast, it was found that Comparative Example 1, which did not use the free radical compound according to the present invention, did not achieve sufficient circuit filling. Furthermore, Comparative Example 2, which used a general polymerization initiator instead of the free radical compound, resulted in a decrease in Tg and an increase in CTE. Furthermore, Comparative Example 3, which did not contain a styrene-based block copolymer, did not achieve sufficient low dielectric properties.

[0213] This application is based on Japanese Patent Application No. 2020-157403, filed on September 18, 2020, the contents of which are incorporated herein by reference.

[0214] In order to express the present invention, the present invention has been properly and sufficiently described above through embodiments with reference to specific examples, drawings, etc., but it should be recognized that those skilled in the art can easily make changes and / or improvements to the above-described embodiments. Therefore, unless changes or improvements made by those skilled in the art deviate from the scope of the claims set forth in the claims, such changes or improvements are construed as being encompassed within the scope of the claims. [Industrial Applicability]

[0215] The present invention has wide industrial applicability in the technical fields related to electronic materials and various devices using the same.

Claims

1. a styrene-based block copolymer; a radical polymerizable compound; The present invention relates to a compound (A) represented by the following formula (1), a compound (B) represented by the following formula (2), and at least one free radical compound selected from the group consisting of a compound (C) having two or more groups each of which is selected from the group represented by the following formula (3-1) and formula (3-2): The resin composition has a content of the free radical compound of 0.001 to 1 part by mass relative to 100 parts by mass of the total of the styrene-based block copolymer and the radically polymerizable compound. 【Chemical 1】 【Chemistry 2】 【Chemistry 3】 【Chemistry 4】 (In formula (1), X Ａ represents an amino group, a cyano group, a hydroxy group, an isothiocyanate group, a methoxy group, a carboxy group, a carbonyl group, an amido group, or a benzoyloxy group; and in formula (2), X B represents a hydrogen atom, an amino group, a cyano group, a hydroxy group, an isothiocyanate group, a methoxy group, a carboxy group, a carbonyl group, an amido group, or a benzoyloxy group.

2. 2. The resin composition according to claim 1, wherein the styrene-based block copolymer has a weight average molecular weight of 10,000 to 200,000.

3. The resin composition according to claim 1 or 2, wherein the styrene-based block copolymer comprises at least one selected from the group consisting of 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 copolymer, styrene (ethylene - ethylene / propylene) styrene copolymer, styrene butadiene styrene copolymer, styrene (butadiene / butylene) styrene copolymer, styrene isobutylene styrene copolymer, and hydrogenated products thereof.

4. The resin composition according to any one of claims 1 to 3, wherein the radical polymerizable compound comprises a polyphenylene ether compound terminally modified with a substituent having a carbon-carbon unsaturated double bond.

5. The resin composition according to claim 4 , wherein the polyphenylene ether compound has a group represented by the following formula (4): 【Chemistry 5】 (In formula (4), R １ represents a hydrogen atom or an alkyl group)

6. The resin composition according to any one of claims 1 to 5, further comprising a reaction initiator.

7. The resin composition according to claim 6, wherein the content ratio (mass ratio) of the free radical compound to the reaction initiator is 0.001:1.0 to 0.1:1.

0.

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

9. A resin-coated film having a resin layer containing the resin composition according to any one of claims 1 to 7 or a semi-cured product of the resin composition, and a support film.

10. A resin-coated metal foil comprising a metal foil and a resin layer containing the resin composition according to any one of claims 1 to 7 or a semi-cured product of the resin composition.

11. A metal-clad laminate having an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 7 or a cured product of the prepreg according to claim 8, and a metal foil.

12. A wiring board having an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 7 or a cured product of the prepreg according to claim 8, and wiring.

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