Resin composition, resin film, resin-equipped film, resin-equipped metal foil, metal-clad laminate, and printed wiring board

Abstract

The present disclosure provides a resin composition that makes it possible to obtain a cured product having good flexibility, while also having low-dielectric properties. The resin composition contains: a polyphenylene ether compound (A) which has an ethylenically unsaturated group at a terminal thereof; a first styrene-based block copolymer (B); and a second styrene-based block copolymer (C) which differs from the first styrene-based block copolymer (B). The second styrene-based block copolymer (C) is a hydrogenated styrene-based block copolymer which has a structural unit derived from a methylstyrene-based monomer.

Description

Resin composition, resin film, resin-coated film, resin-coated metal foil, metal-clad laminate, and printed wiring board

[0001] The present disclosure generally relates to a resin composition, a resin film, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a printed wiring board. More specifically, the present disclosure relates to a resin composition, a resin film made from the resin composition, a resin-coated film made from the resin composition, a resin-coated metal foil made from the resin composition, a metal-clad laminate made from the resin composition, and a printed wiring board made from the resin composition.

[0002] Patent Document 1 discloses a resin composition containing a modified polyphenylene ether compound and triallyl isocyanurate (hereinafter also referred to as TAIC) as a crosslinking curing agent having a carbon-carbon unsaturated double bond. It is stated that the resin composition in Patent Document 1 can provide a cured product with excellent low dielectric properties.

[0003] Furthermore, Patent Document 2 proposes the introduction of an allyl compound in place of TAIC in a polyphenylene ether skeleton in order to improve flexibility.

[0004] JP 2015-086330 A International Publication No. 2023 / 090215

[0005] An object of the present disclosure is to provide a resin composition that can yield a cured product having low dielectric properties and good flexibility, a resin film made from the resin composition, a resin-coated film having a resin layer made from the resin composition, a resin-coated metal foil having a resin layer made from the resin composition, a metal-clad laminate having an insulating layer made from the resin composition, and a printed wiring board having an insulating layer made from the resin composition.

[0006] A resin composition according to one embodiment of the present disclosure comprises a polyphenylene ether compound (A) having an ethylenically unsaturated group at a terminal thereof, a first styrene-based block copolymer (B), and a second styrene-based block copolymer (C) different from the first styrene-based block copolymer (B). The second styrene-based block copolymer (C) is a hydrogenated styrene-based block copolymer having structural units derived from a methylstyrene-based monomer.

[0007] The resin film according to one embodiment of the present disclosure comprises at least one selected from the group consisting of an uncured product of the resin composition and a semi-cured product of the resin composition.

[0008] A resin-coated film according to one embodiment of the present disclosure comprises a resin layer containing at least one selected from the group consisting of an uncured product of the resin composition and a semi-cured product of the resin composition, and a support film overlapping the resin layer.

[0009] A resin-coated metal foil according to one embodiment of the present disclosure comprises a resin layer containing at least one selected from the group consisting of an uncured resin composition and a semi-cured resin composition, and a metal foil overlying the resin layer.

[0010] A metal-clad laminate according to one embodiment of the present disclosure includes an insulating layer containing a cured product of the resin composition, and a metal foil overlying the insulating layer.

[0011] A printed wiring board according to one aspect of the present disclosure includes an insulating layer including a cured product of the resin composition, and wiring overlapping the insulating layer.

[0012] Fig. 1 is a schematic cross-sectional view showing an example of a resin-coated film according to an embodiment of the present disclosure. Fig. 2 is a schematic cross-sectional view showing an example of a resin-coated metal foil according to an embodiment of the present disclosure. Fig. 3 is a schematic cross-sectional view showing an example of a metal-clad laminate according to an embodiment of the present disclosure. Fig. 4 is a schematic cross-sectional view showing a manufacturing process of an example of a printed wiring board according to an embodiment of the present disclosure. Fig. 5 is a schematic cross-sectional view showing a manufacturing process of the same. Fig. 6 is a schematic cross-sectional view showing a manufacturing process of the same. Fig. 7 is a schematic cross-sectional view showing a manufacturing process of the same.

[0013] Hereinafter, embodiments of the present disclosure will be described. However, the present disclosure is not limited to the following embodiments. The following embodiments are merely examples of various embodiments of the present disclosure, and various modifications are possible depending on the design as long as the object of the present disclosure can be achieved. All drawings referred to below are schematic drawings, and the dimensional ratios of the components in the drawings do not necessarily reflect the actual dimensional ratios.

[0014] 1. Development History As the amount of information processed in various electronic devices increases, packaging technologies such as higher integration of semiconductor devices, higher density wiring, and multi-layering are advancing. In addition, wiring boards used in various electronic devices are required to be compatible with high frequencies, such as millimeter wave radar boards for automotive applications.

[0015] The inventors have investigated reducing the dielectric constant and dielectric dissipation factor of flexible substrate materials used to form insulating layers of wiring boards used in various electronic devices in order to increase the signal transmission speed and reduce loss during signal transmission.

[0016] Furthermore, while there is a constant demand for thinner flexible circuit board materials, when using thermosetting polyimides as flexible circuit board materials, it has been proposed to place a layer of thermoplastic polyimide on the surface of the thermosetting polyimide layer because thermosetting polyimides do not have the ability to embed wiring after thermal curing. However, if the thermoplastic polyimide layer is thin, it may contribute to adhesion by roughening the copper foil surface, but its contribution to the embeddability of wiring is small. To embed wiring, a bonding sheet layer must be placed, making it difficult to achieve sufficient thinning.

[0017] Therefore, the inventors have investigated the development of a flexible substrate material that has embeddability even in a single layer.

[0018] The use of high-melting-point thermoplastic resins as low-dielectric materials is being considered, but because of their high melting points, high-temperature pressing is required to ensure embeddability, and there are issues that have been identified, such as a narrow margin for processing conditions and the time it will take to commercialize them.

[0019] On the other hand, when a thermosetting resin is used, it is easy to ensure the adhesion and embeddability of the layer, but when a high concentration of filler is blended in for the purpose of improving the mechanical strength or reducing the linear expansion coefficient, the layer becomes more brittle than when a thermoplastic resin is used, making it difficult to impart sufficient flexibility required for a flexible substrate material.

[0020] Therefore, the inventors investigated polyphenylene ether in order to achieve low dielectric constant and flexibility using a single layer containing a thermosetting resin. Polyphenylene ether has excellent low dielectric properties in high frequency bands (high frequency regions) from the MHz band to the GHz band. For this reason, polyphenylene ether is used, for example, as a high frequency molding material. More specifically, it is preferably used as a substrate material for forming an insulating layer of a printed wiring board provided in an electronic device that uses high frequency bands.

[0021] However, as a result of the inventor's investigations, in the cured products of the resin compositions described in Patent Documents 1 and 2, which use polyphenylene ether, the high reactivity of TAIC and allyl compounds can cause self-polymerization, leaving instability in structural control (property control). Furthermore, the resin composition alone was found to have insufficient flexibility and low toughness in the so-called C-stage after thermal curing, resulting in issues such as the resin portion easily breaking or cracking during flexible substrate processing. Furthermore, because both TAIC and L-DAIC are liquid at room temperature, refrigerated storage is required to prevent bleeding, leaving room for improvement.

[0022] Therefore, the inventors have conducted research and development to obtain a low-dielectric substrate material that is more flexible and easier to handle, and have completed the present disclosure. Note that "low dielectric" refers to a low dielectric constant and a low relative permittivity, and "low dielectric properties" refer to a low dielectric constant and properties that result in a low dielectric constant.

[0023] However, the present disclosure is not to be construed as being limited by the above-described development history. For example, the use of the resin composition of the present disclosure is not limited to the production of flexible printed wiring boards, and the resin composition may also be used for purposes other than the production of flexible printed wiring boards.

[0024] 2. Resin Composition The resin composition according to this embodiment (hereinafter also simply referred to as the resin composition) contains a polyphenylene ether compound (A), a first styrene-based block copolymer (B), and a second styrene-based block copolymer (C).

[0025] The polyphenylene ether compound (A) has an ethylenically unsaturated group at a terminal thereof, and has at least one group selected from the group consisting of a group represented by the following formula (1) and a group represented by the following formula (2) in the molecule:

[0026]

[0027] In formula (1), p represents an integer of 0 to 10. Z represents an arylene group. １ ~R ３ each independently represents a hydrogen atom or an alkyl group.

[0028]

[0029] In formula (2), R ４ represents a hydrogen atom or an alkyl group.

[0030] When the resin composition contains the polyphenylene ether compound (A), a cured product having low dielectric properties can be obtained.

[0031] Furthermore, since the resin composition contains the first styrene-based block copolymer (B), a cured product having good flexibility can be obtained when formed on a film. However, when only the first styrene-based block copolymer (B) is added, the toughness of the skeleton of the polyphenylene ether (A) becomes rate-limiting, and the film breaks or cracks when a certain stress is applied by bending.

[0032] Therefore, by further containing the second styrene-based block copolymer (C) in the resin composition, the low dielectric properties of the cured product prepared from the resin composition are maintained, and when the cured product is molded into a film, the flexibility, including the semi-cured state, is improved, thereby solving the problems such as cracks and breakages that were observed when the allyl compound was used.

[0033] As described above, a cured product can be produced from the resin composition that has low dielectric properties and good flexibility when molded into a film.

[0034] When a resin film is produced using this resin composition, a resin film having low dielectric properties and good flexibility is obtained. When a resin-coated film is produced using this resin composition, a resin-coated film having a resin layer having low dielectric properties and good flexibility is obtained. Furthermore, when a resin-coated metal foil is produced using this resin composition, a resin-coated metal foil having a resin layer having low dielectric properties and good flexibility is obtained. Furthermore, when a metal-clad laminate is produced using this resin composition, a metal-clad laminate having an insulating layer having low dielectric properties and good flexibility is obtained. And when a printed wiring board is produced using this resin composition, a printed wiring board having an insulating layer having low dielectric properties and good flexibility is obtained.

[0035] The components contained in the resin composition will be described in detail below.

[0036] (Polyphenylene Ether) As described above, the resin composition contains a polyphenylene ether compound (A) having an ethylenically unsaturated group at a terminal. This polyphenylene ether compound (A) has, for example, at least one group selected from the group consisting of the group represented by the above formula (1) and the group represented by the above formula (2) in the molecule. Furthermore, the polyphenylene ether (A) preferably has at least one group selected from the group consisting of the group represented by the above formula (1) and the group represented by the above formula (2) at the molecular terminal. That is, the resin composition preferably contains a polyphenylene ether compound (A) terminally modified with at least one group selected from the group consisting of the groups represented by the above formula (1) and the above formula (2).

[0037] As described above, in the formula (1), p represents an integer of 0 to 10. Z represents an arylene group. １ ~R ３ are independent of each other. That is, R １ ~R ３ may be the same group or different groups. １ ~R ３ Each of represents a hydrogen atom or an alkyl group.

[0038] In the above formula (1), when p is 0, this indicates that Z is directly bonded to the end of the polyphenylene ether.

[0039] In addition, in the above formula (1), R １ ~R ３ are all alkyl groups, R １ ~R ３ Each of the groups is preferably an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0040] The arylene group is, for example, a monocyclic aromatic group such as a phenylene group, or a polycyclic aromatic group such as a naphthalene ring. Furthermore, in the aromatic ring contained in this arylene group, for example, a hydrogen atom directly bonded to the aromatic ring may be substituted with a substituent other than a hydrogen atom. Specific examples of the substituent include an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. The alkyl group bonded to this aromatic ring 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. More specifically, the alkyl group is, for example, a methyl group, an ethyl group, a propyl group, a hexyl group, or a decyl group.

[0041] The group represented by the formula (1) is specifically, for example, a vinylbenzyl group (ethenylbenzyl group) or a vinylphenyl group represented by the following formula (4). Specific examples of the vinylbenzyl group include an o-ethenylbenzyl group, an m-ethenylbenzyl group, and a p-ethenylbenzyl group.

[0042]

[0043] In the above formula (2), R ４ is a hydrogen atom or an alkyl group. ４ is an alkyl group, R ４ 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 of the alkyl group include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0044] The group represented by the formula (2) is specifically, for example, an acryloyl group or a methacryloyl group.

[0045] As described above, the polyphenylene ether compound (A) has, for example, at least one group selected from the group consisting of the group represented by the above formula (1) and the group represented by the above formula (2) in the molecule. That is, the polyphenylene ether compound (A) may have, for example, only one kind of the group represented by the above formula (1) and the group represented by the above formula (2), or may have two or more kinds of them. More specifically, the polyphenylene ether compound (A) may have, for example, any one of an o-ethenylbenzyl group, an m-ethenylbenzyl group, and a p-ethenylbenzyl group, or may have two or more kinds of them.

[0046] The polyphenylene ether compound (A) is a compound having a polyphenylene ether chain in the molecule. The polyphenylene ether compound (A) preferably has, for example, a structural unit represented by the following formula (5) in the molecule:

[0047]

[0048] In the above formula (5), t represents 1 to 50. ５ ~R ８ are independent of each other. That is, R ５ ~R ８ may be the same group or different groups.

[0049] In addition, R in the above formula (5) ５ ~R ８ Each of R is, for example, a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkylcarbonyl group. ５ ~R ８ Each of is preferably a hydrogen atom or an alkyl group.

[0050] Here, the above-mentioned R ５ ~R ８ The groups contained in will be explained in more detail.

[0051] The alkyl group 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 of such alkyl groups include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0052] The alkenyl group 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 of the alkenyl group include a vinyl group, an allyl group, and a 3-butenyl group.

[0053] The alkynyl group 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 of the alkynyl group include an ethynyl group and a propargyl group (prop-2-yn-1-yl group).

[0054] The alkylcarbonyl group is a carbonyl group substituted with an alkyl group. The alkylcarbonyl group is preferably an alkylcarbonyl group having 2 to 18 carbon atoms, and more preferably an alkylcarbonyl group having 2 to 10 carbon atoms. Specific examples of the alkylcarbonyl group 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.

[0055] The alkenylcarbonyl group is a carbonyl group substituted with an alkenyl group. The alkenylcarbonyl group is preferably an alkylcarbonyl group having 3 to 18 carbon atoms, and more preferably an alkylcarbonyl group having 3 to 10 carbon atoms. Specific examples of the alkenylcarbonyl group include an acryloyl group, a methacryloyl group, and a crotonoyl group.

[0056] The alkynylcarbonyl group is a carbonyl group substituted with an alkynyl group. The alkynylcarbonyl group is preferably an alkynylcarbonyl group having 3 to 18 carbon atoms, and more preferably an alkynylcarbonyl group having 3 to 10 carbon atoms. Specific examples of the alkynylcarbonyl group include a propioloyl group.

[0057] The weight average molecular weight (Mw) of the polyphenylene ether compound (A) is preferably 500 or more, more preferably 800 or more, and even more preferably 1000 or more. The weight average molecular weight (Mw) of the polyphenylene ether compound (A) is preferably 5000 or less, more preferably 4000 or less, and even more preferably 3000 or less. When the weight average molecular weight (Mw) of the polyphenylene ether compound (A) satisfies the above numerical range, it becomes possible to obtain a cured product of the resin composition that has low dielectric properties, as well as good flexibility and adhesion to metal foil and the like.

[0058] Here, the weight-average molecular weight is not particularly limited as long as it is measured by a general molecular weight measurement method. Specifically, the weight-average molecular weight is preferably measured using, for example, gel permeation chromatography (GPC). Furthermore, when the polyphenylene ether compound (A) has a structural unit represented by the above formula (5) in its molecule, t in the above formula (5) is preferably a numerical value such that the weight-average molecular weight of the polyphenylene ether compound (A) falls within the above range. That is, the value of t in this case is preferably, for example, 1 to 50.

[0059] As described above, the polyphenylene ether compound (A) has in its molecule at least one group selected from the group consisting of the group represented by the above formula (1) and the group represented by the above formula (2). Therefore, even when the weight-average molecular weight of the polyphenylene ether compound (A) is relatively low and falls within the above-mentioned numerical range, the resin composition can give a cured product that has low dielectric properties, as well as good flexibility and adhesion to metal foils and the like.

[0060] In the polyphenylene ether compound (A), the average number of at least one group selected from the group consisting of the group represented by the above formula (1) and the group represented by the above formula (2) per molecule of the polyphenylene ether compound (A) is, for example, preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.5 to 3. When the number of groups per molecule of the polyphenylene ether compound (A) satisfies the above numerical range, it becomes possible to obtain a cured product of the resin composition that has low dielectric properties, as well as good flexibility and adhesion to metal foil and the like.

[0061] In the polyphenylene ether compound (A), the average number of at least one group selected from the group consisting of the group represented by the formula (1) and the group represented by the formula (2) contained per molecule of the polyphenylene ether compound (A) is, for example, a numerical value representing the average value of the number of at least one group selected from the group consisting of the group represented by the formula (1) and the group represented by the formula (2) contained per molecule of the polyphenylene ether compound (A) present in 1 mole of the polyphenylene ether compound (A). This average number of groups can be measured, for example, by measuring the number of hydroxyl groups remaining in the obtained polyphenylene ether compound (A) and calculating the decrease from the number of hydroxyl groups in the polyphenylene ether before it has the group represented by the formula (1) and the group represented by the formula (2), i.e., before it is terminally modified with the group represented by the formula (1) and the group represented by the formula (2).

[0062] The number of hydroxyl groups remaining in the polyphenylene ether compound (A) can be determined, for example, by adding a quaternary ammonium salt (tetraethylammonium hydroxide) that associates with hydroxyl groups to a solution of the polyphenylene ether compound (A) and measuring the UV absorbance of the resulting mixed solution.

[0063] The intrinsic viscosity of the polyphenylene ether compound (A) is preferably 0.03 dL / g or more, more preferably 0.04 dL / g, and even more preferably 0.06 dL / g. The intrinsic viscosity of the polyphenylene ether compound (A) is preferably 0.12 dL / g or less, more preferably 0.11 dL / g or less, and even more preferably 0.095 dL / g or less. When the intrinsic viscosity of the polyphenylene ether compound (A) satisfies the above numerical range, it is possible to obtain a cured product that has low dielectric properties, good flexibility, and good adhesion to metal foils, etc.

[0064] The intrinsic viscosity of the polyphenylene ether compound (A) here is the intrinsic viscosity measured in methylene chloride at 25° C. More specifically, the intrinsic viscosity of the polyphenylene ether compound (A) is, for example, a value measured by dissolving polyphenylene ether (A) in methylene chloride to prepare a 0.18 g / 45 mL methylene chloride solution, adjusting the temperature of the methylene chloride solution to 25° C., and measuring the intrinsic viscosity with a viscometer. Examples of viscometers that can be used to measure the intrinsic viscosity include the AVS500 Visco System manufactured by Schott.

[0065] The polyphenylene ether compound (A) preferably contains at least one selected from the group consisting of a polyphenylene ether compound (a1) having a structure represented by the following formula (6), a polyphenylene ether compound (a2) having a structure represented by the following formula (7), and a polyphenylene ether compound (a3) ​​having a structure represented by the following formula (8): In other words, the polyphenylene ether compound (A) may contain only one of the polyphenylene ether compound (a1) having a structure represented by the following formula (6), the polyphenylene ether compound (a2) having a structure represented by the following formula (7), and the polyphenylene ether compound (a3) ​​having a structure represented by the following formula (8), or may contain two or more of these.

[0066]

[0067]

[0068]

[0069] In the above formulas (6) to (8), R ９ ~R １６ , R １７ ~R ２４ and R ２５ ~R ２８ are independent of each other. That is, R ９ ~R １６ , R １７ ~R ２４ and R ２５ ~R ２８ may be the same group or different groups.

[0070] In addition, in the above formulas (6) to (8), R ９ ~R １６ , R １７ ~R ２４ and R ２５ ~R ２８ Each of R is, for example, 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. ９ ~R １６ , R １７ ~R ２４ and R ２５ ~R ２８ Each of is preferably a hydrogen atom or an alkyl group.

[0071] Furthermore, in the above formulas (6) to (8), X １ ~X ３ are independent of each other. １ ~X ３ may be the same group or different groups. １ ~X ３ Each of the groups is preferably a group represented by the above formula (1) or a group represented by the above formula (2).

[0072] In the above formula (8), s is an integer of 1 to 100, for example.

[0073] In addition, each of A and B in the above formula (6) and the above formula (7) contains at least one structural unit selected from the group consisting of structural units represented by the following formula (9) and structural units represented by the following formula (10):

[0074]

[0075]

[0076] For example, in the above formula (9) and formula (10), each of m and n represents 0 to 20.

[0077] In addition, in the above formula (9) and the above formula (10), R ２９ ~R ３２ and R ３３ ~R ３６ are independent of each other. That is, R ２９ ~R ３２ and R ３３ ~R ３６ may be the same group or different groups.

[0078] Furthermore, in the above formula (9) and the above formula (10), R ２９ ~R ３２ and R ３３ ~R ３６ Each of R is, for example, a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkenylcarbonyl group. ２９ ~R ３２ and R ３３ ~R ３６ Each of is preferably a hydrogen atom or an alkyl group.

[0079] In the above formula (9) and formula (10), it is preferable that m and n represent a numerical value such that the sum of m and n is 1 to 30. That is, it is preferable that m represents 0 to 20, n represents 0 to 20, and the sum of m and n represents 1 to 30.

[0080] Also, R ９ ~R ３６ , R in the above formula (5), ５ ~R ８may be the same as

[0081] In the above formula (7), Y is preferably a linear, branched, or cyclic hydrocarbon having a carbon number of 20 or less. Specific examples of the structure of Y include groups represented by the following formula (11).

[0082]

[0083] In the above formula (11), R ３７ ~R ３８ are independent of each other. That is, R ３７ ~R ３８ may be the same group or different groups.

[0084] In addition, in the above formula (11), R ３７ ~R ３８ is, for example, a hydrogen atom or an alkyl group. Specific examples of the alkyl group include a methyl group. Specific examples of the group represented by formula (11) include a methylene group, a methylmethylene group, or a dimethylmethylene group. Among these, the dimethylmethylene group is preferred as the group represented by formula (11).

[0085] More specific examples of the polyphenylene ether compound (a1) represented by the above formula (6) include polyphenylene ether compounds (a11) represented by the following formula (12).

[0086]

[0087] More specific examples of the polyphenylene ether compound (a2) represented by the above formula (7) include, for example, a polyphenylene ether compound (a21) represented by the following formula (13) or a polyphenylene ether compound (a22) represented by the following formula (14).

[0088]

[0089]

[0090] In the formulas (12) to (14), m and n are the same as m and n in the formulas (9) and (10), respectively. １ ~R ３ , p and Z are, for example, R １ ~R ３ , p and Z. Furthermore, in the formulas (13) and (14), Y is, for example, the same as Y in the formula (7). In the formula (14), R ４ is, for example, R in the above formula (2) ４ is the same as

[0091] Hereinafter, a method for synthesizing the polyphenylene ether compound (A) will be described. In this specification, a method for synthesizing a modified polyphenylene ether compound (A) that has been terminally modified with at least one group selected from the group consisting of a group represented by the above formula (1) and a group represented by the above formula (2) will be described. However, the method for producing the polyphenylene ether compound (A) is not particularly limited as long as it is possible to synthesize a polyphenylene ether compound (A) having in its molecule at least one group selected from the group consisting of a group represented by the above formula (1) and a group represented by the above formula (2).

[0092] A method for synthesizing the modified polyphenylene ether compound (A) terminally modified with at least one group selected from the group consisting of the group represented by the above formula (1) and the group represented by the above formula (2) includes, for example, reacting a polyphenylene ether as a raw material with a compound having at least one group selected from the group consisting of the group represented by the above formula (1) and the group represented by the above formula (2) and a halogen atom.

[0093] The halogen atom is, for example, at least one selected from the group consisting of a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom. Among these atoms, the halogen atom is preferably a chlorine atom. The compound having at least one group selected from the group consisting of the group represented by formula (1) and the group represented by formula (2) above and a halogen atom is, for example, at least one selected from the group consisting of o-chloromethylstyrene, p-chloromethylstyrene, m-chloromethylstyrene, etc.

[0094] The compound having at least one group selected from the group consisting of the group represented by formula (1) and the group represented by formula (2) and a halogen atom may, for example, be used alone or in combination of two or more. More specifically, o-chloromethylstyrene, p-chloromethylstyrene, and m-chloromethylstyrene may each be used alone or in combination of two or more of them.

[0095] In the method for synthesizing the polyphenylene ether compound (A), the polyphenylene ether used as a raw material is not particularly limited as long as it can ultimately synthesize the desired polyphenylene ether compound (A). The polyphenylene ether used as a raw material is, for example, at least one selected from the group consisting of polyphenylene ethers synthesized from 2,6-dimethylphenol, polyphenylene ethers synthesized from bifunctional phenols, polyphenylene ethers synthesized from trifunctional phenols, and polyphenylene ethers such as poly(2,6-dimethyl-1,4-phenylene oxide).

[0096] Here, the bifunctional phenol is a phenol compound having two phenolic hydroxyl groups in the molecule. Specific examples of the bifunctional phenol include tetramethylbisphenol A. The trifunctional phenol is a phenol compound having three phenolic hydroxyl groups in the molecule.

[0097] As described above, the method for synthesizing the polyphenylene ether compound (A) preferably includes a step of reacting a polyphenylene ether, which is a raw material, with a compound having at least one group selected from the group consisting of groups represented by the above formula (1) and groups represented by the above formula (2), and a halogen atom. More specifically, the method for synthesizing the polyphenylene ether compound (A) preferably includes a reaction step of dissolving the polyphenylene ether, which is a raw material, and a compound having at least one group selected from the group consisting of groups represented by the above formula (1) and groups represented by the above formula (2), and a halogen atom in a solvent, and stirring the mixture while heating to cause a reaction therebetween.

[0098] In the method for synthesizing the polyphenylene ether compound (A), the reaction step is preferably carried out in the presence of an alkali metal hydroxide. In this case, the reaction between the polyphenylene ether and the compound having at least one group selected from the group consisting of the group represented by the formula (1) and the group represented by the formula (2) and a halogen atom proceeds favorably. Specific examples of the alkali metal hydroxide include sodium hydroxide. The alkali metal hydroxide is preferably used in the form of an aqueous solution. That is, in the method for producing the polyphenylene ether compound (A), an aqueous sodium hydroxide solution is preferably used in the reaction step.

[0099] In the reaction step in the method for producing the polyphenylene ether compound (A), it is preferable to set reaction conditions under which the polyphenylene ether as raw materials and at least one group selected from the group consisting of the group represented by the above formula (1) and the group represented by the above formula (2) can react favorably with a compound having a halogen atom.

[0100] The reaction temperature in the reaction step is, for example, preferably 20° C. or higher and 100° C. or lower, and more preferably 30° C. or higher and 100° C. or lower. The reaction time in the reaction step is, for example, preferably 0.5 hours or higher and 20 hours or lower, and more preferably 0.5 hours or higher and 10 hours or lower.

[0101] In the synthesis method of the polyphenylene ether compound (A), it is preferable that the solvent used in the reaction step is capable of dissolving the raw material polyphenylene ether and the compound having at least one group selected from the group consisting of the group represented by the above formula (1) and the group represented by the above formula (2) and a halogen atom, and does not inhibit the reaction thereof. Specific examples of such solvents include toluene, etc.

[0102] In the method for synthesizing the polyphenylene ether compound (A), when an alkali metal hydroxide is used in the reaction step, it is preferable to use the alkali metal hydroxide in combination with a phase transfer catalyst. That is, it is preferable to react the starting polyphenylene ether with a compound having at least one group selected from the group consisting of groups represented by formula (1) and groups represented by formula (2) above and a halogen atom in the presence of the alkali hydroxide and the phase transfer catalyst. In this case, the reaction between the starting polyphenylene ether and the compound having at least one group selected from the group consisting of groups represented by formula (1) and groups represented by formula (2) above and a halogen atom proceeds more smoothly. Specific examples of the phase transfer catalyst include quaternary ammonium salts such as tetra-n-butylammonium bromide.

[0103] (Styrene-based block copolymer) As described above, the resin composition contains the first styrene-based block copolymer (B) and the second styrene-based block copolymer (C). The second styrene-based block copolymer (C) is a hydrogenated styrene-based block copolymer (HSBC) having structural units derived from a methylstyrene-based monomer.

[0104] The structural unit derived from a methylstyrene-based monomer is a structural unit consisting of a residue of a methylstyrene-based monomer. The methylstyrene-based monomer is at least one selected from the group consisting of methylstyrene and methylstyrene having a substituent. The hydrogenated styrene-based block copolymer is a hydrogenated form (hydrogenate) of a styrene-based block copolymer (SBC). In other words, the second styrene-based block copolymer (C) can be said to be a hydrogenated form of a styrene-based block copolymer having structural units derived from a methylstyrene-based monomer. The first styrene-based block copolymer (B) is at least one selected from the group consisting of non-hydrogenated styrene-based block copolymers and hydrogenated styrene-based block copolymers not having structural units derived from a methylstyrene-based monomer.

[0105] The reactivity of the first styrene-based block copolymer (B) with the polyphenylene ether compound (A) tends to be low, or the first styrene-based block copolymer (B) has no reactivity with the polyphenylene ether compound (A). Therefore, if the styrene-based block copolymer in the resin composition contains only the first styrene-based block copolymer (B), it is difficult to ensure sufficient strength of the resin film when the resin composition is dried by heating to produce a semi-cured resin film. Furthermore, increasing the amount of the first styrene-based block copolymer (B) to improve the flexibility of the cured product can cause problems such as a decrease in the glass transition temperature and an increase in the linear expansion coefficient of the cured product.

[0106] On the other hand, the structural unit derived from the methylstyrene-based monomer enhances the reactivity of the second styrene-based block copolymer (C) with the polyphenylene ether compound (A). Therefore, if the styrene-based block copolymer in the resin composition contains only the second styrene-based block copolymer (C), when the resin composition is dried by heating to produce a semi-cured resin film, the reaction between the second styrene-based block copolymer (C) and the polyphenylene ether compound (A) progresses to a certain extent, improving the strength and flexibility of the resin film, but increasing the brittleness of the cured product and making it more susceptible to breakage.

[0107] However, in this embodiment, since the resin composition contains the first styrene-based block copolymer (B) and the second styrene-based block copolymer (C), the flexibility of the resin film in the B-stage and the flexibility of the cured product can both be improved, and the low dielectric properties and high glass transition temperature of the cured product can be ensured.

[0108] (First styrene-based block copolymer) The first styrene-based block copolymer (B) is preferably a resin contained in a resin composition used to produce an insulating layer provided in a metal-clad laminate, a printed wiring board, etc. Such a first styrene-based block copolymer (B) includes, for example, at least one selected from the group consisting of 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. Furthermore, the first styrene-based block copolymer (B) more preferably includes at least one selected from the group consisting of styrene-butadiene-styrene copolymer, styrene-(ethylene / butylene)-styrene copolymer, and hydrogenated products and modified products thereof.

[0109] The first styrene-based block copolymer (B) may be used alone or in combination of two or more kinds.

[0110] The weight-average molecular weight of the first styrene-based block copolymer (B) is preferably 10,000 or more, more preferably 50,000 or more, and even more preferably 60,000 or more. The weight-average molecular weight of the first styrene-based block copolymer (B) is preferably 300,000 or less, more preferably 250,000 or less, and even more preferably 200,000 or less. When the weight-average molecular weight of the first styrene-based block copolymer (B) satisfies the above numerical range, it is possible to produce a cured product from the resin composition that has low dielectric properties, good flexibility, and good adhesion to metal foil, etc.

[0111] (Second Styrenic Copolymer) The second styrenic copolymer (C) is a hydrogenated styrenic block copolymer (HSBC) having structural units derived from a methylstyrene-based monomer.

[0112] The methylstyrene-based monomer contains at least one selected from the group consisting of methylstyrene and methylstyrene having a substituent. Methylstyrene has a structure in which a methyl group is bonded to a carbon on the aromatic ring of styrene. The substituted methylstyrene contains at least one selected from the group consisting of, for example, a compound having a structure in which a substituent is bonded to a carbon on the aromatic ring of methylstyrene, and a compound having a structure in which a substituent is bonded to the α-carbon of the vinyl group in methylstyrene. The substituent is, for example, an alkyl group, more specifically, a methyl group. The methylstyrene-based monomer contains, for example, at least one selected from the group consisting of o-methylstyrene, p-methylstyrene, o-methyl-isopropenylbenzene (o-methyl-α-methylstyrene), p-methyl-isopropenylbenzene (p-methyl-α-methylstyrene), o-ethyl-isopropenylbenzene (o-ethyl-α-methylstyrene), and 2,4-dimethylstyrene. The proportion of the structural units derived from the methylstyrene-based monomer relative to all structural units possessed by the second styrene-based copolymer (C) is, for example, 10% by mass or more and 70% by mass or less. That is, the proportion of the methylstyrene-based monomer in all the monomers constituting the second styrene-based copolymer (C) is, for example, 10% by mass or more and 70% by mass or less, and more preferably 10% by mass or more and 50% by mass or less.

[0113] The second styrene copolymer (C) is, for example, a hydrogenated form of a styrene block copolymer (SBC) having structural units derived from a methylstyrene monomer. In this case, the styrene block copolymer has, for example, at least one polymer block A (hard segment) and at least one polymer block B (soft segment) before hydrogenation. In the SBC, i.e., before hydrogenation, the polymer block A is a rigid block formed by polymerization of a first vinyl aromatic compound. The polymer block B is formed by polymerization of a monomer containing a conjugated diene. The polymer block B may be a copolymer block formed by polymerization of a monomer containing a styrene compound (a) having a radical reactive group, at least one conjugated diene (b), and optionally a second vinyl aromatic compound (c) that is the same as or different from the first vinyl aromatic compound.

[0114] In embodiments, the first vinyl aromatic compound used to construct polymer block A can be any aromatic compound having at least one vinyl group. Examples of compounds that the first vinyl aromatic compound can include include substituted styrenes, vinyl naphthalenes and substituted vinyl naphthalenes, vinyl indenes, vinyl anthracenes, and 1,1-diphenylethylenes, as well as mixtures thereof. Specific examples of compounds include vinyl aromatic compounds having 8 to 20 carbon atoms, such as o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, isopropenylbenzene (α-methylstyrene), vinyl naphthalene, vinyl toluene, and vinyl xylene, or mixtures thereof.

[0115] In embodiments, the first vinyl aromatic compound comprises at least one selected from the group consisting of, for example, o-methylstyrene, p-methylstyrene, o-ethylstyrene, p-ethylstyrene, o-isopropylstyrene, para-isopropylstyrene, o-methyl-isopropenylbenzene (o-methyl-α-methylstyrene), p-methyl-isopropenylbenzene (p-methyl-α-methylstyrene), o-ethyl-isopropenylbenzene (o-ethyl-α-methylstyrene), p-ethyl-isopropenylbenzene (p-ethyl-α-methylstyrene), o-isopropyl-isopropenylbenzene (o-isopropyl-α-methylstyrene), and p-isopropyl-isopropenylbenzene (p-isopropyl-α-methylstyrene).

[0116] In embodiments, the first vinyl aromatic compound preferably comprises p-methylstyrene, p-methyl-isopropenylbenzene (p-methyl-α-methylstyrene), or a mixture thereof.

[0117] In an embodiment, when the monomer constituting the polymer block B includes a styrene compound (a) having a radical reactive group, the styrene compound (a) may be, for example, a substituted styrene, vinylbenzocyclobutene, vinyldihydroindene, vinyltetrahydronaphthalene, or any combination thereof.

[0118] In an embodiment, the conjugated diene monomer (b) constituting the polymer block B contains, for example, at least one selected from the group consisting of butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1-phenyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 3-butyl-1,3-octadiene, farnesene, myrcene, piperylene, and cyclohexadiene.

[0119] In an embodiment, when the monomer constituting the polymer block B contains a second vinyl aromatic compound (c), the second vinyl aromatic compound (c) may be any aromatic compound having at least one vinyl group. Examples of compounds that may be included in the second vinyl aromatic compound (c) include styrene and substituted styrenes, vinyl naphthalene and substituted vinyl naphthalenes, vinyl indenes, vinyl anthracenes, 1,1-diphenylethylene, and mixtures of two or more thereof. Other examples of compounds that may be included in the second vinyl aromatic compound (c) include vinyl aromatic compounds having 8 to 20 carbon atoms, such as o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, α-methylstyrene, vinyl naphthalene, vinyl toluene, vinyl xylene, and mixtures of two or more thereof.

[0120] (Other Components) The resin composition may contain, as necessary, components other than the polyphenylene ether compound (A), the first styrene-based block copolymer (B), and the second styrene-based block copolymer (C), for example, within a range that does not impair the effects of the present disclosure. Examples of components that can be contained in the resin composition include flame retardants, initiators, curing accelerators, antifoaming agents, antioxidants, metal deactivators, plasticizers, lubricants, polymerization inhibitors, polymerization retarders, dispersants, leveling agents, heat stabilizers, antistatic agents, UV absorbers, silane coupling agents, adhesion promoters, dyes, pigments, lubricants, and additives such as fillers.

[0121] Furthermore, the resin composition may contain, in addition to the polyphenylene ether compound (A), a thermosetting compound other than the polyphenylene ether compound (A). Such a thermosetting compound includes, for example, at least one selected from the group consisting of an epoxy resin, an unsaturated polyester resin, a thermosetting polyimide resin, a resin containing an aromatic hydrocarbon, a resin containing an aliphatic hydrocarbon, a methacrylate monomer, and an acrylate monomer.

[0122] As described above, the resin composition may contain a flame retardant. By including a flame retardant in the resin composition, the flame retardancy of a cured product of the resin composition is improved. Specific examples of flame retardants in fields where halogen-based flame retardants such as bromine-based flame retardants are used include, for example, ethylene dipentabromobenzene, ethylene bistetrabromoimide, decabromodiphenyl oxide, and tetradecabromodiphenoxybenzene, each of which has a melting point of 300°C or higher. Specific examples of flame retardants in fields where halogen-free materials are required include, for example, phosphate ester-based flame retardants, phosphazene-based flame retardants, bisdiphenylphosphine oxide-based flame retardants, phosphinate-based flame retardants, and melamine polyphosphate-based flame retardants.

[0123] As described above, the resin composition may contain an initiator (reaction initiator). The reaction initiator is preferably capable of accelerating the curing reaction of the polyphenylene ether compound (A). Specific examples of the reaction initiator include oxidizing agents such as α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, bis(α,α-dimethylbenzyl)peroxide, bis(1-methyl-1-phenylethyl)peroxide), benzoyl peroxide, 3,3',5,5'-tetramethyl-1,4-diphenoquinone, chloranil, 2,4,6-tri-t-butylphenoxyl, t-butylperoxyisopropyl monocarbonate, and azobisisobutyronitrile. Among these, the reaction initiator preferably contains α,α'-bis(t-butylperoxy-m-isopropyl)benzene. Furthermore, a metal carboxylate or the like may be used as needed. That is, it is preferable to use a reaction initiator and a carboxylic acid residual metal salt in combination. In this case, the curing reaction of the resin composition is likely to be accelerated. In addition, the reaction initiator may be used alone or in combination of two or more types.

[0124] As described above, the resin composition may contain a curing accelerator. The curing accelerator is preferably a compound capable of accelerating the curing reaction of the resin composition. Specific examples of the curing accelerator include imidazoles and derivatives thereof, organic phosphorus compounds, amines such as secondary amines and tertiary amines, quaternary ammonium salts, organic boron compounds, and metal soaps.

[0125] The imidazoles and derivatives thereof include, for example, at least one selected from the group consisting of 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-phenyl-4-methylimidazole, 2-phenylimidazole, and 1-benzyl-2-methylimidazole.

[0126] The organic phosphorus compound includes, for example, at least one selected from the group consisting of triphenylphosphine, diphenylphosphine, phenylphosphine, tributylphosphine, trimethylphosphine, and the like.

[0127] The amines include, for example, at least one selected from the group consisting of dimethylbenzylamine, triethylenediamine, triethanolamine, and 1,8-diazabicyclo[5.4.0]-7-undecene (DBU).

[0128] Examples of quaternary ammonium salts include tetrabutylammonium bromide.

[0129] The organic boron compound includes at least one selected from the group consisting of tetraphenylboron salts such as 2-ethyl-4-methylimidazole tetraphenylborate, and tetra-substituted phosphonium tetra-substituted borates such as tetraphenylphosphonium ethyltriphenylborate.

[0130] The metal soap refers to, for example, a fatty acid metal salt, and may be a linear fatty acid metal salt or a cyclic fatty acid metal salt. Specific examples of the metal soap include linear fatty acid metal salts and cyclic aliphatic metal salts having 6 to 10 carbon atoms. More specifically, the metal soap includes at least one selected from the group consisting of linear fatty acids such as stearic acid, lauric acid, ricinoleic acid, and octylic acid, cyclic fatty acids such as naphthenic acid, and aliphatic metal salts formed with metals such as lithium, magnesium, calcium, barium, copper, and zinc. The curing accelerator may be used alone or in combination of two or more.

[0131] As described above, the resin composition may contain a filler such as an inorganic filler. The filler can improve the heat resistance and flame retardancy of the cured product of the resin composition. The filler includes at least one selected from the group consisting of, for example, silica such as spherical silica, alumina, titanium oxide, titanic acid compounds, and mica, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, talc, aluminum borate, barium sulfate, and calcium carbonate. Among these, the filler is preferably silica such as spherical silica, mica, or talc, or more preferably spherical silica. However, in some cases, the filler may be flat or petal-shaped.

[0132] The filler may be used alone or in combination of two or more. The surface of the filler may be surface-treated with a silane coupling agent.

[0133] The resin composition may contain an elastomer other than a styrene-based block copolymer. The elastomer can increase the flexibility of the cured product. Examples of elastomers include polybutadiene, polyurethane, polyester, COC (cyclic olefin copolymer), silicone, and urethane acrylate. The elastomer may also include a modified polybutadiene. The modified polybutadiene may include at least one selected from the group consisting of a compound in which epoxy groups are introduced into the molecule by epoxidizing at least a portion of the carbon-carbon double bonds in the polybutadiene, a compound in which both terminals of the polybutadiene are glycidyl etherified, a compound in which OH groups are introduced into the terminals of the polybutadiene molecular chain, a hydrogenated polybutadiene, and a compound in which a functional group such as OH or COOH is introduced into the middle of the polybutadiene molecular chain.

[0134] (Content) The percentage of the polyphenylene ether compound (A) relative to the resin component (organic component) in the resin composition is preferably 20% by mass or more, more preferably 30% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less.

[0135] When the percentage of the polyphenylene ether compound (A) is 20% by mass or more, the cured product has a moderately high glass transition temperature and therefore good heat resistance, and when this percentage is 70% by mass or less, the high-temperature elastic modulus of the cured product is unlikely to decrease excessively.

[0136] Here, the resin component (organic component) in the resin composition refers to an organic component containing the polyphenylene ether compound (A), the first styrene-based block copolymer (B), and the second styrene-based block copolymer (C). When the resin composition contains a curing agent, the resin component contains the curing agent. When the resin composition contains a thermosetting component other than the polyphenylene ether compound (A), the resin component contains the thermosetting component. When the resin composition contains an elastomer other than the styrene-based block copolymer, the resin component contains the elastomer.

[0137] The percentage of the first styrene-based block copolymer (B) relative to the resin component (organic component) in the resin composition is preferably 10% by mass or more, more preferably 20% by mass or more. Furthermore, the percentage of the first styrene-based block copolymer (B) relative to the resin component (organic component) in the resin composition is preferably 50% by mass or less, more preferably 40% by mass or less. When the percentage of the first styrene-based block copolymer (B) is 10% by mass or more, the flexibility of the cured product can be particularly improved. When this percentage is 50% by mass or less, the cured product can have a moderately high glass transition temperature and therefore good heat resistance.

[0138] The percentage of the second styrene-based block copolymer (C) relative to the resin component (organic component) in the resin composition is preferably 5% by mass or more, more preferably 10% by mass or more. Furthermore, the percentage of the second styrene-based block copolymer (C) relative to the resin component (organic component) in the resin composition is preferably 40% by mass or less, more preferably 30% by mass or less. When the percentage of the second styrene-based block copolymer (C) is 5% by mass or more, the resin composition (semi-cured product) in a B-stage state can have good flexibility. When this percentage is 40% by mass or less, the high-temperature elastic modulus of the cured product is less likely to decrease excessively, and warping and undulation under thermal load can be effectively suppressed.

[0139] When the resin composition contains a filler, the content of the filler per 100 parts by mass of the resin component (organic component) in the resin composition is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, and even more preferably 100 parts by mass or more. The upper limit of the filler content is preferably 400 parts by mass or less, more preferably 350 parts by mass or less, and even more preferably 300 parts by mass or less.

[0140] When the filler content is 50 parts by mass or more, the high-temperature elastic modulus of the C-stage resin composition (cured product) is unlikely to decrease excessively, and an increase in the coefficient of linear thermal expansion (CTE) can be suppressed. When the filler content is 400 parts by mass or less, the cured product can have good flexibility, and can be effectively prevented from becoming brittle and prone to cracking.

[0141] The resin component in the resin composition may contain only the polyphenylene ether compound (A), the first styrene-based block copolymer (B), and the second styrene-based block copolymer (C). When the resin component contains a component other than the polyphenylene ether compound (A), the first styrene-based block copolymer (B), and the second styrene-based block copolymer (C), the content of this component is preferably more than 0 parts by mass and not more than 100 parts by mass, more preferably more than 0 parts by mass and not more than 40 parts by mass, per 100 parts by mass of the total of the polyphenylene ether compound (A), the first styrene-based block copolymer (B), and the second styrene-based block copolymer (C).

[0142] 3. Method for Producing Resin Composition A method for producing a resin composition will be described.

[0143] Examples of a method for producing the resin composition include a method of mixing the polyphenylene ether compound (A), the first styrene-based block copolymer (B), and the second styrene-based block copolymer (C) to a predetermined content.

[0144] The resin composition may contain an organic solvent. That is, the resin composition is preferably used as a varnish-like resin composition containing an organic solvent. Note that a varnish-like resin composition containing an organic solvent is not included in the components contained in the above-mentioned resin composition. The type and amount of the organic solvent can be appropriately set depending on the viscosity, compatibility, and processability.

[0145] Such a varnish-like resin composition can be produced as follows. First, components soluble in organic solvents are added to an organic solvent and dissolved while stirring to prepare a mixture. Some of the resin components may be diluted with a solvent before addition. When preparing the mixture, the components may be heated and stirred. Next, components that are insoluble in organic solvents are added to the mixture and dispersed to the desired dispersed state using a ball mill, bead mill, planetary mixer, disperser, high-pressure homogenizer, ultrasonic wave, roll mill, or the like, to produce a varnish-like resin composition. Furthermore, the organic solvent used here is preferably capable of dissolving, for example, polyphenylene ether (A), the first styrene-based block copolymer (B), and the second styrene-based block copolymer (C), and does not inhibit the curing reaction of the resin composition. Specific examples of organic solvents include toluene, acetone, methyl ethyl ketone (MEK), and N-methylpyrrolidone (NMP).

[0146] 4. Application Examples of Resin Composition Application examples of the resin composition will be described.

[0147] The resin composition is used to produce a resin film, a resin layer included in a resin-coated film, a resin layer included in a resin-coated metal foil, an insulating layer included in a metal-clad laminate, and an insulating layer included in a printed wiring board. More specifically, the resin film contains at least one selected from the group consisting of an uncured product of the resin composition and a semi-cured product of the resin composition.

[0148] The resin layer of the resin-coated film contains at least one selected from the group consisting of an uncured resin composition and a semi-cured resin composition. The resin layer of the resin-coated metal foil contains at least one selected from the group consisting of an uncured resin composition and a semi-cured resin composition. The insulating layer of the metal-clad laminate contains a cured resin composition. The insulating layer of the printed wiring board contains a cured resin composition.

[0149] 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. In other words, the term "semi-cured product" refers to a resin composition that has been semi-cured, i.e., a resin composition that has been brought to a B-stage. For example, when a resin composition is heated, its viscosity gradually decreases at the beginning of heating. Thereafter, the viscosity gradually increases as the solvent contained in the resin composition evaporates and resin curing begins. Thus, "semi-cured" refers to, for example, a state between when the viscosity begins to increase and when the resin composition is completely cured. In this embodiment, the term "semi-cured product" also refers to, for example, a state in which the unsaturated bonds of the polyphenylene ether compound (A) and the curing agent contained in the resin composition do not react, and curing has not begun, but the fluidity of the resin composition simply decreases due to the evaporation of the solvent from the resin composition. In this case, when the varnish-like resin composition is used to produce the resin layer 12 of the resin-coated film 11 described below or the resin layer 22 of the resin-coated metal foil 21, the content of the solvent contained in the resin layers 12, 22 is preferably 1.5 mass% or less, and more preferably 1 mass% or less.

[0150] The minimum bending radius of the semi-cured film of the resin composition is preferably 2 mm or less. In this case, the resin composition can produce a cured product with good flexibility. In this embodiment, the minimum bending radius of the semi-cured film refers to the minimum radius of curvature of the bending clamp when a semi-cured product made from the resin composition can be bent at least once under the measurement conditions of a load of 0.5 kgf, a bending angle of 135 degrees, and a test speed of 175 cpm in an MIT test based on JIS P8115. The test piece used for the measurement is prepared, for example, by cutting a test piece on which a circuit has been fabricated to a width of 15 mm and a length of 130 mm. Furthermore, to perform the minimum bending test of the film, for example, an MIT testing device (manufactured by Toyo Seiki Seisakusho, model number: MIT-DA) is used.

[0151] Furthermore, the semi-cured product of the resin composition more preferably has a minimum film bending radius of 1 mm or less, and even more preferably 0.5 mm or less.

[0152] The minimum bending radius of the cured film of the resin composition is preferably 2 mm or less. In this case, the resin composition can also be used to obtain a cured film having good flexibility and adhesion to metal foil, etc. The minimum bending radius of the cured film of the resin composition is measured, for example, by the same method as that for the semi-cured film of the present embodiment.

[0153] Furthermore, the minimum bending radius of the film of the cured product of the resin composition is more preferably 1 mm or less, and even more preferably 0.5 mm or less.

[0154] (Resin Film) Next, the resin film according to this embodiment (hereinafter also simply referred to as resin film) will be described.

[0155] The resin film contains at least one selected from the group consisting of a resin composition and a semi-cured product of the resin composition.

[0156] As described above, the resin film may contain a semi-cured product of the resin composition, or may contain an uncured resin composition.

[0157] Next, a method for producing a resin film will be described.

[0158] Examples of methods for producing a resin film include a method of producing a resin film by mixing a resin composition and a solvent according to the method described above to prepare a varnish-like resin composition, applying the varnish-like resin composition, and heating it to form a resin film.

[0159] Examples of methods for applying the varnish-like resin composition include methods using various coaters such as a bar coater.

[0160] Subsequently, the varnish-like resin composition is applied, and then the applied varnish-like resin composition is heated to volatilize the organic solvent from the varnish-like resin composition and remove the organic solvent. At this time, the temperature at which the applied varnish-like resin composition is heated is preferably, for example, 80°C or higher and 180°C or lower. Furthermore, the time for which the applied varnish-like resin composition is heated is preferably 1 minute or higher and 20 minutes or lower. In this way, the resin composition is formed as an uncured or semi-cured resin film.

[0161] As described above, the resin composition can produce a cured product having low dielectric properties and good flexibility. Therefore, an insulating layer having low dielectric properties and good flexibility can be produced from the resin film. This resin film can be suitably used to produce a printed wiring board having an insulating layer having low dielectric properties and good flexibility. For example, by laminating this resin film on a printed wiring board, a multilayer printed wiring board can be produced.

[0162] The method for producing the resin film is not limited to the above method. That is, the resin film can be produced by an appropriate method using the resin composition. Furthermore, the resin film is not limited to being used only for producing printed wiring boards. That is, the resin film can be used for various purposes.

[0163] (Resin-Coated Film) Next, the resin-coated film 11 according to this embodiment will be described.

[0164] FIG. 1 is a schematic cross-sectional view showing an example of a resin-coated film 11. As shown in FIG.

[0165] 1 , the resin-coated film 11 includes a resin layer 12 containing at least one selected from the group consisting of a resin composition and a semi-cured product of the resin composition, and a support film 13. That is, the resin-coated film 11 includes a resin layer 12 containing at least one selected from the group consisting of an uncured product of a resin composition and a semi-cured product of the resin composition, and a support film 13 overlapping the resin layer 12.

[0166] The resin-coated film 11 may have another layer between the resin layer 12 and the support film 13, for example.

[0167] Furthermore, as described above, the resin layer 12 may contain a semi-cured resin composition or an uncured resin composition. That is, the resin-coated film 11 may be a resin-coated film 11 including a resin layer 12 containing a semi-cured resin composition (a B-stage resin composition) and a support film 13, or a resin-coated film 11 including a resin layer 12 containing a resin composition before curing (a A-stage resin composition) and a support film 13.

[0168] The support film 13 further includes at least one electrically insulating film selected from the group consisting of, for example, polyester film, polyethylene terephthalate (PET) film, polyimide film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, polyamide film, polycarbonate film, and polyarylate film.

[0169] The resin-coated film 11 may include, for example, a cover film. By including the cover film, it is possible to prevent the inclusion of foreign matter, etc. Specific examples of the cover film include a polyolefin film, a polyester film, and a polymethylpentene film.

[0170] The support film 13 and the cover film may be subjected to surface treatment such as matte treatment, corona treatment, release treatment, and roughening treatment.

[0171] Next, a method for producing the resin-coated film 11 will be described.

[0172] Examples of methods for manufacturing the resin-coated film 11 include a method in which a resin composition and a solvent are mixed according to the method described above to prepare a varnish-like resin composition, and the varnish-like resin composition is applied to a support film 13 and heated to form a resin layer 12 that overlaps the support film 13, thereby manufacturing the resin-coated film 11.

[0173] Examples of methods for applying the varnish-like resin composition to the support film 13 include methods using various coaters such as a bar coater.

[0174] Next, the varnish-like resin composition is applied to the support film 13, and the applied varnish-like resin composition is heated to volatilize the organic solvent from the varnish-like resin composition and remove the organic solvent. At this time, the temperature at which the applied varnish-like resin composition is heated is preferably, for example, 80°C or higher and 180°C or lower. Furthermore, the time for heating the applied varnish-like resin composition is preferably 1 minute or higher and 20 minutes or lower. In this way, the resin composition is formed on the support film 13 as an uncured or semi-cured resin layer 12, thereby producing the resin-attached film 11.

[0175] As described above, the resin composition can be used to produce a cured product that has low dielectric properties and good flexibility. Therefore, the resin-attached film 11 includes a resin layer 12 that provides an insulating layer that has low dielectric properties and good flexibility. This resin-attached film 11 can be suitably used to produce a printed wiring board that includes an insulating layer that has low dielectric properties and good flexibility. A multilayer printed wiring board can be produced by, for example, laminating this resin-attached film 11 on a printed wiring board and then peeling off the support film 13, or by laminating the resin-attached film 11 on a printed wiring board after peeling off the support film 13.

[0176] The method for producing the resin-coated film 11, which includes the resin layer 12 made from a resin composition and the support film 13 overlying the resin layer 12, is not limited to the above-described method. That is, the resin-coated film 11 can be produced by any appropriate method using a resin composition. Furthermore, the use of the resin-coated film 11 is not limited to producing printed wiring boards. That is, the resin-coated film 11 can be used in a variety of applications.

[0177] (Resin-Coated Metal Foil) Next, the resin-coated metal foil 21 according to this embodiment will be described.

[0178] FIG. 2 is a schematic cross-sectional view showing an example of a resin-coated metal foil 21. As shown in FIG.

[0179] 2 , the resin-coated metal foil 21 includes a resin layer 22 containing at least one selected from the group consisting of a resin composition and a semi-cured product of the resin composition, and a metal foil 23 overlying the resin layer 22. That is, the resin-coated metal foil 21 includes a resin layer 22 containing at least one selected from the group consisting of an uncured product of a resin composition and a semi-cured product of the resin composition, and a metal foil 23 overlying the resin layer 22. The resin-coated metal foil 21 may also include another layer between the resin layer 22 and the metal foil 23.

[0180] As described above, the resin layer 22 may contain a semi-cured resin composition or an uncured resin composition. That is, the resin-coated metal foil 21 may be a resin-coated metal foil 21 including a resin layer 22 containing a semi-cured resin composition (a B-stage resin composition) and a metal foil 23, or a resin-coated metal foil 21 including a resin layer 22 containing an uncured resin composition (an A-stage resin composition) and a metal foil 23.

[0181] Furthermore, for example, an appropriate metal foil is used as the metal foil 23. Specific examples of the metal foil 23 include copper foil, aluminum foil, and the like.

[0182] The resin-coated metal foil 21 may be provided with, for example, a cover film etc. For example, the same cover film as that used to produce the resin-coated film 11 can be used as the cover film.

[0183] Next, a method for producing the resin-coated metal foil 21 will be described.

[0184] Examples of methods for manufacturing the resin-coated metal foil 21 include a method in which, according to the above-mentioned method, a resin composition and a solvent are mixed to prepare a varnish-like resin composition, and the varnish-like resin composition is applied to the metal foil 23 and heated to form a resin layer 22 that overlaps the metal foil 23, thereby manufacturing the resin-coated metal foil 21.

[0185] Examples of methods for applying the varnish-like resin composition to the metal foil 23 include methods using a bar coater or various coaters.

[0186] Next, the varnish-like resin composition is applied to the metal foil 23, and the applied varnish-like resin composition is heated to volatilize the organic solvent from the varnish-like resin composition and remove the organic solvent. At this time, the temperature at which the applied varnish-like resin composition is heated is preferably 80°C or higher and 180°C or lower. Furthermore, the time for which the applied varnish-like resin composition is heated is preferably 1 minute or higher and 20 minutes or lower. In this way, a resin layer 22 containing an uncured or semi-cured resin composition is formed on the metal foil 23, and the resin-coated metal foil 21 is manufactured.

[0187] The resin composition can be used to produce a cured product that has low dielectric properties and good flexibility. Therefore, the resin-coated metal foil 21 includes the resin layer 22 that provides an insulating layer that has low dielectric properties and good flexibility. This resin-coated metal foil 21 can be suitably used to produce a printed wiring board that has an insulating layer that has low dielectric properties and good flexibility.

[0188] The method for producing the resin-coated metal foil 21 including the resin layer 22 made from the resin composition and the metal foil 23 overlying the resin layer 22 is not limited to the above-described method. That is, the resin-coated metal foil 21 can be produced by any appropriate method using the resin composition. Furthermore, the resin-coated metal foil 21 is not limited to being used only for producing printed wiring boards. That is, the resin-coated metal foil 21 can be used for various purposes.

[0189] (Metal-clad laminate) Next, a metal-clad laminate 31 according to this embodiment using a resin composition will be described.

[0190] FIG. 3 is a schematic cross-sectional view showing an example of a metal-clad laminate 31. As shown in FIG.

[0191] 3, the metal-clad laminate 31 includes an insulating layer 32 made of a resin composition and a metal foil 33 overlying the insulating layer 32. That is, the metal-clad laminate 31 has the insulating layer 32 containing a cured product of the resin composition and the metal foil 33 overlying the insulating layer 32.

[0192] As described above, the insulating layer 32 is preferably a cured product of a resin composition.

[0193] The thickness of the metal foil 33 can be appropriately set depending on the purpose. Specific examples of the metal foil 33 include copper foil and aluminum foil.

[0194] Next, a method for manufacturing the metal-clad laminate 31 will be described.

[0195] An example of a method for producing the metal-clad laminate 31 is a method in which an insulating layer 32 is produced from a cured product of a resin composition, the insulating layer 32 is formed on a metal foil 33, and then heated and pressurized to produce the metal-clad laminate 31. More specifically, a metal foil 33 such as copper foil is placed on both or one of the upper and lower surfaces of the insulating layer 32 containing the cured product of the resin composition, and the metal foil 33 and the insulating layer 32 are heated and pressurized to form them into an integrated laminate, thereby producing a metal-clad laminate 31 with the metal foil 33 attached to both or one of the surfaces.

[0196] The insulating layer 32 may also be produced using the above-described resin-coated film 11. More specifically, the insulating layer 32 of the metal-clad laminate 31 can be produced by heating and curing the resin layer 12 of the resin-coated film 11.

[0197] Furthermore, the insulating layer 32 may be produced using the above-described resin-coated metal foil 21. More specifically, the insulating layer 32 of the metal-clad laminate 31 can be produced by heating and curing the resin layer 22 of the resin-coated metal foil 21. In this case, the metal foil 23 of the resin-coated metal foil 21 becomes the metal foil 33 of the metal-clad laminate 31.

[0198] The heating and pressing conditions when manufacturing the metal-clad laminate 31 are preferably set appropriately depending on the thickness of the metal-clad laminate 31 to be manufactured, the type of composition of the insulating layer 32, and the like.

[0199] The heating temperature when manufacturing the metal-clad laminate 31 is preferably 170° C. or higher and 230° C. or lower. The pressure when manufacturing the metal-clad laminate 31 is preferably 1.5 MPa or higher and 5.0 MPa or lower. Furthermore, the heating and pressing time when manufacturing the metal-clad laminate 31 is preferably 60 minutes or higher and 150 minutes or lower.

[0200] When manufacturing the metal-clad laminate 31, the thickness of the metal foil 33 can be appropriately set depending on the desired purpose. For example, a metal foil 33 having a thickness of 0.2 μm to 70 μm can be used. When the metal foil has a thickness of, for example, 10 μm or less, a carrier-attached copper foil having a release layer and a carrier may be used to improve handling. The thickness of the metal foil 33 is preferably 0.2 μm to 35 μm, and more preferably 1 μm to 18 μm. Even when the metal foil 33 is thin, when a resin composition is used to manufacture the metal-clad laminate 31, the adhesion between the insulating layer 32 in the metal-clad laminate 31 and the metal foil 33 is good. Furthermore, in the metal-clad laminate 31, the peel strength between the insulating layer 32 (cured product of the resin composition) and the metal foil 33 is preferably 0.50 N / mm or more, more preferably 0.55 N / mm or more, and even more preferably 0.60 N / mm or more.

[0201] A cured product having low dielectric properties and good flexibility can be produced from the resin composition. Therefore, a metal-clad laminate 31 including an insulating layer 32 containing the cured product of this resin composition has an insulating layer 32 having low dielectric properties and good flexibility. Such a metal-clad laminate 31 can be suitably used, for example, in a flexible copper clad laminate (FCCL). When this metal-clad laminate 31 is used to produce a printed wiring board, a printed wiring board can be produced that has an insulating layer that has low dielectric properties and good flexibility.

[0202] It should be noted that the metal-clad laminate 31 is not limited to being used as a flexible copper-clad laminate. That is, the metal-clad laminate 31 can be used for various applications. Furthermore, the method for manufacturing the metal-clad laminate 31 including the insulating layer 32 made from a resin composition and the metal foil 33 overlapping the insulating layer 32 is not limited to the above-described method. That is, the metal-clad laminate 31 can be manufactured by any appropriate method using the resin composition.

[0203] (Printed Wiring Board) Next, the printed wiring board 41 according to this embodiment will be described.

[0204] 4 to 7 are schematic cross-sectional views of the printed wiring board 41. FIG.

[0205] As shown in Fig. 6, printed wiring board 41 includes insulating layer 42 made of a resin composition and wiring 43 overlapping insulating layer 42. That is, printed wiring board 41 has insulating layer 42 containing a cured product of the resin composition overlapped on wiring 43 formed by partially removing metal foil 45 overlapping base material layer 44. Furthermore, printed wiring board 41 may further include metal foil 46 overlapping insulating layer 42 as shown in Fig. 7.

[0206] Specific examples of the material of the base material layer 44 include polyimide, liquid crystal polymer (hereinafter also referred to as LCP), and fluororesin. Among these, polyimide is preferred as the material of the base material layer 44. In the printed wiring board 41, the peel strength between the insulating layer 42 (cured product of the resin composition) and the polyimide base material layer 44 is preferably 0.25 N / mm or more, more preferably 0.30 N / mm or more, and even more preferably 0.40 N / mm or more.

[0207] Furthermore, the resin composition may be used as a material for base material layer 44 of printed wiring board 41. In this case, base material layer 44 of printed wiring board 41 is preferably a cured product of a prepreg including a resin composition and a fibrous base material.

[0208] The metal foil 45 may be the same as that used when the metal-clad laminate 31 is produced.

[0209] Next, a method for manufacturing the printed wiring board 41 will be described.

[0210] The method for manufacturing the printed wiring board 41 is as follows: First, as shown in FIG.

[0211] 5, the metal foil 45 is partially removed to form wiring 43 that will become the circuit of the printed wiring board on the surface of the base material layer 44. Examples of a method for forming the circuit include a circuit formation method using a semi-additive process (SAP) or a modified semi-additive process (MSAP).

[0212] 6, an insulating layer 42 made of a resin composition is formed on the formed wiring 43. For example, the insulating layer 42 may be formed by applying a varnish-like resin composition prepared by mixing a resin composition with a solvent onto the wiring 43 and curing the applied varnish-like resin composition.

[0213] In this manner, printed wiring board 41 is produced. As described above, metal foil 46 may be further laminated on the produced insulating layer 42, as shown in Fig. 7. Then, wiring may be formed by partially removing this metal foil 46, and further insulating layers may be laminated, and this process may be repeated to form a multilayer structure.

[0214] Printed wiring board 41 includes insulating layer 42 containing a cured product that has low dielectric properties, yet is flexible and has good adhesion to metal foil, etc. That is, printed wiring board 41 includes insulating layer 42 that has low dielectric properties, yet is flexible and has good adhesion to metal foil, etc. Such printed wiring board 41 can be suitably used for, for example, flexible printed circuits (FPCs).

[0215] The method for producing printed wiring board 41 is not limited to the above method, and printed wiring board 41 can be produced by any suitable method using the resin composition.

[0216] Furthermore, the printed wiring board 41 is not limited to being used only as a flexible printed circuit board, and can be used for a variety of purposes.

[0217] 5. Aspects As shown in the above embodiments, the present disclosure includes the following aspects.

[0218] The resin composition of the first aspect contains a polyphenylene ether compound (A) having an ethylenically unsaturated group at its terminal, a first styrene-based block copolymer (B), and a second styrene-based block copolymer (C) different from the first styrene-based block copolymer (B). The second styrene-based block copolymer (C) is a hydrogenated styrene-based block copolymer having structural units derived from a methylstyrene-based monomer.

[0219] According to this embodiment, there is an advantage that a cured product can be obtained from the resin composition that has low dielectric properties, as well as flexibility and good adhesion to metal foils and the like.

[0220] In the second embodiment, in the first embodiment, the polyphenylene ether compound (A) has at least one group selected from the group consisting of a group represented by formula (1) and a group represented by formula (2) in the molecule.

[0221]

[0222] In formula (1), p represents an integer of 0 to 10, Z represents an arylene group, and R １ ~R ３ each independently represents a hydrogen atom or an alkyl group.

[0223]

[0224] In formula (2), R ４ represents a hydrogen atom or an alkyl group.

[0225] In a third aspect, in the first or second aspect, the minimum bending radius of the film of the semi-cured resin composition is 1 mm or less.

[0226] In a fourth aspect, in any one of the first to third aspects, the minimum bending radius of a film of the cured product of the resin composition is 1 mm or less.

[0227] In a fifth aspect, in any one of the first to fourth aspects, the percentage of the polyphenylene ether compound (A) relative to the total amount of resin components in the resin composition is 20 mass% or more and 70 mass% or less.

[0228] In a sixth aspect, in any one of the first to fifth aspects, the percentage of the first styrene-based block copolymer (B) relative to the total amount of resin components in the resin composition is 10% by mass or more and 50% by mass or less.

[0229] In a seventh aspect, in any one of the first to sixth aspects, the percentage of the second styrene-based block copolymer (C) relative to the total amount of resin components in the resin composition is 5% by mass or more and 40% by mass or less.

[0230] The resin film of the eighth aspect contains at least one selected from the group consisting of an uncured product of the resin composition of any one of the first to seventh aspects and a semi-cured product of the resin composition.

[0231] The resin-coated film of the ninth aspect comprises a resin layer containing at least one selected from the group consisting of an uncured resin composition and a semi-cured resin composition of any one of the first to seventh aspects, and a support film overlapping the resin layer.

[0232] The resin-coated metal foil of the tenth aspect comprises a resin layer containing at least one selected from the group consisting of an uncured resin composition and a semi-cured resin composition of any one of the first to seventh aspects, and a metal foil overlying the resin layer.

[0233] A metal-clad laminate according to an eleventh aspect includes an insulating layer containing a cured product of the resin composition according to any one of the first to seventh aspects, and a metal foil overlying the insulating layer.

[0234] A printed wiring board according to a twelfth aspect includes an insulating layer containing a cured product of the resin composition according to any one of the first to seventh aspects, and wiring overlapping the insulating layer.

[0235] Specific examples of this embodiment will be described below, but this embodiment is not limited to the following examples.

[0236] Examples 1 to 11 and Comparative Examples 1 to 4 In these examples, each component used in preparing the resin composition will be described.

[0237] 1. Raw Materials (Polyphenylene Ether Compound: PPE) SA9000: Polyphenylene ether compound having a terminal methacryloyl group (modified polyphenylene ether in which the terminal hydroxyl group of polyphenylene ether is modified with a methacryloyl group, represented by the above formula (14) in which Y in formula (14) is a dimethylmethylene group (represented by formula (11) in which R ３７ and R ３８ where R is a methyl group, SA9000 manufactured by SABIC Innovative Plastics, weight average molecular weight Mw 2000, number of terminal functional groups 2) OPE-2St: A polyphenylene ether compound having a vinylbenzyl group (ethenylbenzyl group) at the terminal, manufactured by Mitsubishi Gas Chemical Company, Inc. Product name OPE-2st 1200. Number average molecular weight 1200. It has a group shown in the above formula (1), where Z is a phenylene group, and R １ ~R ３ are all hydrogen atoms and p is 1.

[0238] (First styrene-based block copolymer) Tuftec H1041: a hydrogenated styrene-based thermoplastic elastomer having no structural units derived from methylstyrene-based monomers (Tuftec H1041 from Asahi Kasei Corporation).

[0239] (Second styrene-based block copolymer) MD3501: a hydrogenated styrene-based modified thermoplastic elastomer having structural units derived from methylstyrene-based monomers (MD3501 manufactured by Kraton Corporation).

[0240] (Polybutadiene) JP-100: Polybutadiene compound having an epoxy group in the molecule (JP-100 manufactured by Nippon Soda Co., Ltd., oxirane concentration: 7.7% by mass).

[0241] (Curing agent: allyl compound) L-DAIC: long-chain alkyl-modified diallyl isocyanurate (L-DAIC from Shikoku Chemicals Corporation).

[0242] (Initiator) Perbutyl P: α,α'-di(t-butylperoxy)diisopropylbenzene (Perbutyl P (PBP) manufactured by NOF Corporation).

[0243] (Filler) SC2300-SVJ: Spherical silica surface-treated with vinylsilane (SC2300-SVJ manufactured by Admatechs Co., Ltd.).

[0244] 2. Varnish Preparation Method First, each component other than the filler was added to toluene (solvent) and mixed in the composition (parts by mass) shown in Table 1 so that the final solid content concentration was 50 mass%. The mixture was stirred for 60 minutes using a disperser. Thereafter, the 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).

[0245] 3. Evaluation Test (Preparation of Evaluation Substrate) Next, an evaluation substrate to be used for measuring the dielectric properties (dielectric constant and dielectric loss tangent), glass transition point, minimum bending radius of the cured film, and minimum bending radius of the semi-cured film was obtained as follows.

[0246] First, the varnish obtained by the above method was applied to a copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd., product number: 3EC-VLP, thickness 18 μm) to a thickness of 100 μm, and heated at 100 to 160° C. for 2 to 10 minutes to form a semi-cured resin layer on the copper foil, thereby obtaining a resin-coated metal foil.

[0247] A copper foil similar to that used previously was placed on the resin layer of the resin-coated metal foil to obtain a laminate. The laminate was heated and pressurized under vacuum at 200°C and 4 MPa for 2 hours to cure the semi-cured resin layer on the resin-coated metal foil and form an insulating layer, thereby obtaining a laminate. This laminate was used as an evaluation substrate. The thickness of the insulating layer on the evaluation substrate was 100 μm.

[0248] (Preparation of semi-cured film) The varnish obtained by the method described above was applied to a copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd., product number: 3EC-VLP, thickness 18 μm) to a thickness of 100 μm, and heated at 100 to 160° C. for 2 to 10 minutes to form a semi-cured resin layer on the copper foil, thereby obtaining a resin-coated metal foil. The copper foil was removed from this resin-coated metal foil by chemical etching to obtain a semi-cured film.

[0249] The evaluation substrate fabricated as described above was evaluated by the following method.

[0250] [Dielectric Properties (Dielectric Constant and Dielectric Loss Tangent)] The copper foil was removed from the evaluation substrate prepared in the above "Preparation of Evaluation Substrate" to obtain a single insulating layer. The dielectric constant and dielectric loss tangent of this insulating layer at 10 GHz were measured using a cavity resonator perturbation method. Specifically, the dielectric constant and dielectric loss tangent of the insulating layer at 10 GHz were measured using a network analyzer (Agilent Technologies, Inc., Model N5230A).

[0251] As a result, the dielectric constant was evaluated as "A" when it was 3.0 or less, and "B" when it was more than 3.0. The dielectric loss tangent was evaluated as "A" when it was 0.0020 or less, "B" when it was more than 0.0020 and less than 0.0050, and "C" when it was more than 0.0050.

[0252] [Glass Transition Point] The glass transition point of the insulating layer in the evaluation substrate prepared in the above "Preparation of Evaluation Substrate" was measured by dynamic mechanical analysis (DMA).

[0253] As a result, the glass transition point was evaluated as "A" when it was 180°C or higher, "B" when it was 100°C or higher but lower than 180°C, and "C" when it was lower than 100°C.

[0254] [Evaluation of bending of semi-cured film] The film produced in the above "Preparation of semi-cured film" was subjected to a pass / fail judgment based on whether it could be bent at least once using an MIT testing device (manufactured by Toyo Seiki Seisaku-sho, Ltd., model number: MIT-DA) under measurement conditions of a load of 500 gf, a bending angle of 135 degrees, and a test speed of 175 cpm, with the bending clamp radius of curvature set to 1 mm. The solvent content relative to the entire printed wiring board was 0.8%.

[0255] As a result, the film was rated as "A" when no breakage, cracking or whitening occurred, and "B" when breakage, cracking or whitening occurred.

[0256] [Evaluation of bending of cured film] The copper foil was removed by chemical etching from the evaluation substrate prepared in the above "Preparation of evaluation substrate" to obtain a cured film consisting of an insulating layer. This cured film was subjected to a pass / fail evaluation based on whether it could be bent at least once using an MIT testing device (manufactured by Toyo Seiki Seisaku-sho, Ltd., model number: MIT-DA) under measurement conditions of a load of 500 gf, a bending angle of 135 degrees, and a test speed of 175 cpm, with the bending clamp radius of curvature set to 1 mm.

[0257] As a result, the case where no breakage, cracking or whitening occurred in the cured film was rated as "A", and the case where breakage, cracking or whitening occurred was rated as "B".

[0258] The results of the above evaluations are shown in Tables 1 and 2.

[0259]

[0260]

[0261] As described above, the resin composition according to the present embodiment can be used to produce a cured product that has low dielectric properties and good flexibility. The present invention also provides a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a printed wiring board, which contain the cured product produced from the resin composition.

[0262] REFERENCE SIGNS LIST 11 resin-coated film 12, 22 resin layer 13 support film 21 resin-coated metal foil 23, 33, 45, 46 metal foil 31 metal-clad laminate 32, 42 insulating layer 41 printed wiring board 43 wiring 44 substrate layer

Claims

1. A resin composition comprising: a polyphenylene ether compound (A) having an ethylenically unsaturated group at its terminal; a first styrenic block copolymer (B); and a second styrenic block copolymer (C) different from the first styrenic block copolymer (B), wherein the second styrenic block copolymer (C) is a hydrogenated styrenic block copolymer having structural units derived from a methylstyrene monomer.

2. The polyphenylene ether compound (A) has at least one group selected from the group consisting of a group represented by formula (1) and a group represented by formula (2) in the molecule, In formula (1), p represents an integer of 0 to 10, Z represents an arylene group, and R １ ~R ３ each independently represents a hydrogen atom or an alkyl group, In formula (2), R ４ The resin composition according to claim 1 , wherein represents a hydrogen atom or an alkyl group.

3. The resin composition according to claim 1, wherein the minimum bending radius of a semi-cured film of said resin composition is 1 mm or less.

4. The resin composition according to claim 1, wherein the minimum bending radius of a film of the cured resin composition is 1 mm or less.

5. The resin composition according to claim 1, wherein the percentage of the polyphenylene ether compound (A) relative to the total amount of resin components in the resin composition is 20% by mass or more and 70% by mass or less.

6. The resin composition according to claim 1, wherein the percentage of the first styrene-based block copolymer (B) relative to the total amount of resin components in the resin composition is 10% by mass or more and 50% by mass or less.

7. The resin composition according to claim 1, wherein the percentage of the second styrene-based block copolymer (C) relative to the total amount of resin components in the resin composition is 5% by mass or more and 40% by mass or less.

8. A resin film comprising at least one material selected from the group consisting of an uncured product of the resin composition according to claim 1 and a semi-cured product of said resin composition.

9. A resin-coated film comprising: a resin layer containing at least one material selected from the group consisting of an uncured product of the resin composition according to claim 1 and a semi-cured product of said resin composition; and a support film overlapping said resin layer.

10. A resin-coated metal foil comprising: a resin layer containing at least one material selected from the group consisting of an uncured resin composition according to any one of claims 1 to 7 and a semi-cured resin composition; and a metal foil overlying the resin layer.

11. A metal-clad laminate comprising: an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 7; and a metal foil overlying the insulating layer.

12. A printed wiring board comprising: an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 7; and wiring overlapping the insulating layer.

Images