Resin composition for wiring boards, prepreg for wiring boards, resin-coated film for wiring boards, resin-coated metal foil for wiring boards, metal-clad laminate for wiring boards, and wiring boards

Abstract

One aspect of the present invention provides a resin composition which contains (A) a polyphenylene ether compound that has at least one of a group represented by formula (1) and a group represented by formula (2) in each molecule, (B) a curing agent, (C) a titanic acid compound filler, and (D) a silica filler, wherein the content ratio of the titanic acid compound filler (C) to the silica filler (D) is from 10:90 to 90:10 in terms of the mass ratio. In formula (1), p represents a number from 0 to 10; Ar represents an arylene group; and each of R1 to R3 independently represents a hydrogen atom or an alkyl group. In formula (2), R4 represents a hydrogen atom or an alkyl group.

Description

[Technical Field]

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

[0002] Printed circuit boards used in electronic devices, such as those used for antennas, are required to be able to handle high frequencies. The substrate material for the insulating layer of such high-frequency-compatible printed circuit boards requires a low dielectric loss tangent to reduce signal transmission losses. Furthermore, a high relative permittivity is also required to enable miniaturization of the printed circuit board.

[0003] The insulating layer provided on a wiring board may be manufactured using a prepreg, which is made by impregnating a fibrous substrate such as glass cloth with a resin composition. In such a prepreg, if there is a large difference between the relative permittivity of the fibrous substrate and the relative permittivity of the cured resin composition, the relative permittivity of the cured prepreg will differ depending on the amount of resin composition blended with the fibrous substrate. In such cases, in metal-clad laminates and wiring boards obtained using a prepreg with glass cloth, the relative permittivity of the insulating layer will differ depending on the thickness and other factors, as the amount of resin composition blended will differ. Therefore, even if the metal-clad laminates and wiring boards are manufactured using the same resin composition, the relative permittivity of the insulating layer may differ, which may affect the substrate design, such as the wiring width. This effect is known to be particularly pronounced in multilayer wiring boards. For this reason, it is necessary to consider the difference in the relative permittivity of the insulating layer when designing a substrate.

[0004] It is known that printed circuit boards made using prepregs containing glass cloth can develop a distortion called skew, which degrades signal quality. In particular, the degradation of signal quality due to skew is known to be more pronounced in printed circuit boards used in electronic devices that utilize high frequency bands. This is thought to be because, in metal-clad laminates and printed circuit boards made using prepregs containing glass cloth, a difference in relative permittivity occurs between the areas where the yarn constituting the glass cloth is present and the areas where it is not.

[0005] Therefore, in prepregs in which a resin composition is impregnated into a fibrous substrate such as glass cloth, a resin composition is needed that yields a cured product having a relative permittivity close to that of the fibrous substrate. If the relative permittivity of the cured product of the resin composition is lower than that of the fibrous substrate, the relative permittivity of the cured product of the resin composition is needed to be high in order to bring it closer to that of the fibrous substrate. To address this point, a resin composition is needed that yields a cured product with a high relative permittivity. As mentioned above, the resin composition is also needed to yield a cured product with a low dielectric loss tangent in order to reduce signal transmission losses in the wiring board. Furthermore, the substrate material for constituting the insulating layer of the wiring board is needed not only to have a high relative permittivity and a low dielectric loss tangent, but also to yield a cured product with improved curability and excellent heat resistance. This high heat resistance is particularly desired in multilayer wiring boards and the like.

[0006] Examples of the resin composition used for manufacturing the insulating layer provided on the wiring board include, for example, the resin composition described in Patent Document 1. Patent Document 1 describes a resin composition containing a polyphenylene ether derivative having an organic group substituted with an unsaturated aliphatic hydrocarbon group and a maleimide compound. According to Patent Document 1, it is disclosed that a resin composition capable of exhibiting dielectric properties (low dielectric constant and low dielectric loss tangent) in a high-frequency band of 10 GHz or higher can be provided. Further, Patent Document 1 describes that an inorganic filler is contained in the resin composition, and examples of the inorganic filler include barium titanate, potassium titanate, strontium titanate, and calcium titanate.

[0007] It is considered that the relative dielectric constant can be increased by incorporating a filler having a high relative dielectric constant, for example, barium titanate, potassium titanate, strontium titanate, calcium titanate, etc. described in Patent Document 1. However, even if the relative dielectric constant can be increased by incorporating a filler having a high relative dielectric constant, there are cases where the dielectric loss tangent also increases or the heat resistance etc. deteriorates.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

[0009] The present invention has been made in view of such circumstances, and an object thereof is to provide a resin composition from which a cured product having a high relative dielectric constant, a low dielectric loss tangent, and excellent heat resistance can be obtained. Another object of the present invention is to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board obtained by using the above resin composition.

[0010] One aspect of the present invention is a resin composition comprising a polyphenylene ether compound (A) having at least one of a group represented by the following formula (1) and a group represented by the following formula (2) in its molecule, a curing agent (B), a titanate compound filler (C), and a silica filler (D), wherein the content ratio of the titanate compound filler (C) to the silica filler (D) is 10:90 to 90:10 by mass.

[0011] [ka] In formula (1), p represents 0 to 10, Ar represents an arylene group, and R1 to R3 each independently represent a hydrogen atom or an alkyl group.

[0012] [ka] In formula (2), R4 represents a hydrogen atom or an alkyl group. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of a prepreg according to an embodiment of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view showing an example of a metal-clad laminate according to an embodiment of the present invention. [Figure 3] Figure 3 is a schematic cross-sectional view showing an example of a wiring board according to an embodiment of the present invention. [Figure 4] Figure 4 is a schematic cross-sectional view showing another example of a wiring board according to an embodiment of the present invention. [Figure 5] Figure 5 is a schematic cross-sectional view showing an example of a resin-coated metal foil according to an embodiment of the present invention. [Figure 6] Figure 6 is a schematic cross-sectional view showing an example of a resin-coated film according to an embodiment of the present invention. [Modes for carrying out the invention]

[0014] To increase the dielectric constant of a cured resin composition, as mentioned above, it is conceivable to include a filler with a high dielectric constant. Furthermore, to further increase the dielectric constant of a cured resin composition, it is conceivable to increase the content of the filler with a high dielectric constant in the resin composition. However, according to the inventors' studies, simply including a filler with a high dielectric constant does not always increase the dielectric constant, depending on the composition of the resin components and fillers contained in the resin composition. As mentioned above, even if the dielectric constant can be increased, the heat resistance may decrease or the dielectric loss tangent may increase. In such cases, if the content of the filler with a high dielectric constant in the resin composition is increased to further increase the dielectric constant, the heat resistance may decrease further or the dielectric loss tangent may increase. Therefore, after various studies, the inventors found that not only the resin components contained in the resin composition, but also the type and composition of the filler, affect the dielectric properties such as the dielectric constant and dielectric loss tangent of the cured product, and also affect the heat resistance of the cured product. The inventors, after conducting various studies including an examination of this effect, found that the above objective can be achieved by the present invention described below.

[0015] The embodiments of the present invention will be described below, but the present invention is not limited thereto.

[0016] [Resin composition] A resin composition according to one embodiment of the present invention comprises a polyphenylene ether compound (A) having at least one of the group represented by the following formula (1) and the group represented by the following formula (2) in its molecule, a curing agent (B), a titanate compound filler (C), and a silica filler (D), wherein the content ratio of the titanate compound filler (C) to the silica filler (D) is 10:90 to 90:10 by mass. When a resin composition with such a configuration is cured, a cured product with a high dielectric constant, a low dielectric loss tangent, and excellent heat resistance can be obtained.

[0017] It is believed that by curing the polyphenylene ether compound (A) contained in the resin composition together with the curing agent (B), the polyphenylene ether compound (A) is suitably cured, and a cured product with excellent heat resistance is obtained. Furthermore, since the resin composition contains the polyphenylene ether compound (A), it is believed that curing will result in a cured product with a low dielectric loss tangent. This cured product is thought to have not only a low dielectric loss tangent but also a low relative permittivity, but it is believed that by including the titanate compound filler (C) in the resin composition, the relative permittivity of the cured product can be increased. Moreover, by including not only the titanate compound filler (C) but also the silica filler (D) in the resin composition and adjusting their content ratio to the above ratio, it is believed that the relative permittivity can be increased while suppressing an increase in the dielectric loss tangent of the cured product, and the heat resistance can also be increased. From these considerations, it is believed that a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance can be obtained.

[0018] Furthermore, in the case of a prepreg obtained by impregnating a fibrous substrate with a resin composition, if the difference between the relative permittivity of the cured resin composition and the relative permittivity of the fibrous substrate is large, the relative permittivity of the cured prepreg will differ depending on the amount of resin composition blended with the fibrous substrate. In this case, for example, the amount of resin composition blended will differ depending on the thickness of the prepreg, and the relative permittivity of the resulting cured prepreg will differ. In contrast, as described above, the resin composition according to this embodiment has a high relative permittivity, so the difference with the relative permittivity of the fibrous substrate can be made small. In this case, the difference in relative permittivity of the cured prepreg for each prepreg due to different amounts of resin composition blended in the prepreg becomes small. Therefore, even if there are differences in thickness, etc., the difference in relative permittivity is small for the insulating layer provided on the wiring board. Also, as described above, the cured resin composition has a high relative permittivity, so the difference between this relative permittivity and the relative permittivity of the fibrous substrate provided on the prepreg becomes small, and the occurrence of skew in the finally obtained wiring board can be suppressed.

[0019] Furthermore, as printed circuit boards become thinner, semiconductor packages on which semiconductor chips are mounted tend to warp, making mounting defects more likely. To suppress warping of semiconductor packages on which semiconductor chips are mounted, the insulating layer is required to have a low coefficient of thermal expansion. Therefore, the substrate material for constituting the insulating layer of the printed circuit board is required to yield a cured product with a low coefficient of thermal expansion. From this, substrate materials such as printed circuit boards are required to have a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance, as well as a low coefficient of thermal expansion. In contrast, the resin composition according to this embodiment yields a cured product that not only has a high relative permittivity and a low dielectric loss tangent, but also excellent heat resistance and a low coefficient of thermal expansion.

[0020] (Polyphenylene ether (A)) The polyphenylene ether (A) is not particularly limited as long as it is a polyphenylene ether compound having at least one (substituent) of the group represented by the following formula (1) and the group represented by the following formula (2) in its molecule. Examples of the polyphenylene ether compound include modified polyphenylene ether compounds that are terminally modified by at least one of the group represented by the following formula (1) and the group represented by the following formula (2), and other polyphenylene ether compounds having at least one of the group represented by the following formula (1) and the group represented by the following formula (2) at the molecular terminals.

[0021] [ka] In formula (1), R1 to R3 are independent of each other. That is, R1 to R3 may be the same group or different groups. R1 to R3 represent hydrogen atoms or alkyl groups. Ar represents an arylene group. p represents 0 to 10. In formula (1), if p is 0, it indicates that Ar is directly bonded to the end of the polyphenylene ether.

[0022] The aforementioned arylene group is not particularly limited. Examples of such arylene groups include monocyclic aromatic groups such as phenylene groups, and polycyclic aromatic groups such as naphthalene rings. Furthermore, the arylene group also includes derivatives in which the hydrogen atom bonded to the aromatic ring is substituted with a functional group such as an alkenyl group, alkynyl group, formyl group, alkylcarbonyl group, alkenylcarbonyl group, or alkynylcarbonyl group.

[0023] The alkyl group is not particularly limited, but for example, alkyl groups having 1 to 18 carbon atoms are preferred, and alkyl groups having 1 to 10 carbon atoms are more preferred. Specifically, examples include methyl groups, ethyl groups, propyl groups, hexyl groups, and decyl groups.

[0024] [ka] In formula (2), R4 represents a hydrogen atom or an alkyl group.

[0025] The alkyl group is not particularly limited, but for example, alkyl groups having 1 to 18 carbon atoms are preferred, and alkyl groups having 1 to 10 carbon atoms are more preferred. Specifically, examples include methyl groups, ethyl groups, propyl groups, hexyl groups, and decyl groups.

[0026] Examples of the group represented by formula (1) include the vinylbenzyl group (ethenylbenzyl group) represented by formula (3) below. Examples of the group represented by formula (2) include the acryloyl group and the methacryloyl group.

[0027] [ka] More specifically, the substituent (at least one of the group represented by formula (1) and the group represented by formula (2)) includes vinyl benzyl groups (ethenyl benzyl groups) such as o-ethenyl benzyl groups, m-ethenyl benzyl groups, and p-ethenyl benzyl groups, vinyl phenyl groups, acryloyl groups, and methacryloyl groups. The polyphenylene ether compound may have one substituent or two or more substituents. For example, the polyphenylene ether compound may have any of the o-ethenyl benzyl groups, m-ethenyl benzyl groups, and p-ethenyl benzyl groups, or it may have two or three of these substituents.

[0028] The polyphenylene ether compound has a polyphenylene ether chain in its molecule, and preferably has a repeating unit represented by the following formula (4) in its molecule.

[0029] [ka] In formula (4), t represents 1 to 50. Furthermore, R5 to R8 are independent of each other. That is, R5 to R8 may be the same group or different groups. Also, R5 to R8 represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. Among these, hydrogen atoms and alkyl groups are preferred.

[0030] In R5 to R8, the functional groups listed are specifically as follows:

[0031] The alkyl group is not particularly limited, but for example, alkyl groups having 1 to 18 carbon atoms are preferred, and alkyl groups having 1 to 10 carbon atoms are more preferred. Specifically, examples include methyl groups, ethyl groups, propyl groups, hexyl groups, and decyl groups.

[0032] The alkenyl group is not particularly limited, but for example, an alkenyl group having 2 to 18 carbon atoms is preferred, and an alkenyl group having 2 to 10 carbon atoms is more preferred. Specifically, examples include vinyl groups, allyl groups, and 3-butenyl groups.

[0033] The alkynyl group is not particularly limited, but for example, an alkynyl group having 2 to 18 carbon atoms is preferred, and an alkynyl group having 2 to 10 carbon atoms is more preferred. Specifically, examples include the ethynyl group and the propa-2-in-1-yl group (propargyl group).

[0034] The alkylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkyl group, but for example, alkylcarbonyl groups having 2 to 18 carbon atoms are preferred, and alkylcarbonyl groups having 2 to 10 carbon atoms are more preferred. Specifically, examples include acetyl group, propionyl group, butyryl group, isobutyryl group, pivaloyl group, hexanoyl group, octanoyl group, and cyclohexylcarbonyl group.

[0035] The alkenylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkenyl group, but for example, an alkenylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkenylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specifically, examples include acryloyl groups, methacryloyl groups, and crotonoyl groups.

[0036] The alkynylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkynyl group, but for example, an alkynylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkynylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specifically, for example, a propioloyl group can be mentioned.

[0037] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polyphenylene ether compound are not particularly limited, but are preferably 500 to 5000, more preferably 800 to 4000, and even more preferably 1000 to 3000. Here, the weight-average molecular weight and number-average molecular weight can be measured by a general molecular weight measurement method, specifically values ​​measured using gel permeation chromatography (GPC). Furthermore, if the polyphenylene ether compound has repeating units represented by formula (4) in its molecule, it is preferable that t is a value such that the weight-average molecular weight and number-average molecular weight of the polyphenylene ether compound fall within this range. Specifically, t is preferably 1 to 50.

[0038] When the weight-average molecular weight and number-average molecular weight of the polyphenylene ether compound are within the above range, it possesses the excellent low dielectric properties of polyphenylene ether, resulting in a cured product that is not only superior in heat resistance but also in moldability. This is thought to be due to the following: In ordinary polyphenylene ethers, when the weight-average molecular weight and number-average molecular weight are within the above range, the molecular weight is relatively low, so the heat resistance tends to decrease. In this respect, the polyphenylene ether compound according to this embodiment has one or more unsaturated double bonds at the terminal, so it is thought that as the curing reaction proceeds, a cured product with sufficiently high heat resistance can be obtained. Furthermore, when the weight-average molecular weight and number-average molecular weight of the polyphenylene ether compound are within the above range, the molecular weight is relatively low, so it is thought to have excellent moldability. Therefore, it is thought that such a polyphenylene ether compound can be obtained that is not only superior in heat resistance but also in moldability.

[0039] The average number of substituents (terminal functional groups) at the molecular ends of each molecule of the polyphenylene ether compound is not particularly limited. Specifically, it is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.5 to 3. If the number of terminal functional groups is too small, it tends to be difficult to obtain a cured product with sufficient heat resistance. On the other hand, if the number of terminal functional groups is too large, the reactivity becomes too high, which may lead to problems such as a decrease in the shelf life of the resin composition or a decrease in the fluidity of the resin composition. In other words, using such a polyphenylene ether compound may result in molding defects such as voids occurring during multilayer molding due to insufficient fluidity, making it difficult to obtain a highly reliable printed circuit board.

[0040] The number of terminal functional groups in a polyphenylene ether compound can be expressed as a numerical value representing the average number of substituents per molecule of the polyphenylene ether compound present in 1 mole of the compound. This number of terminal functional groups can be measured, for example, by measuring the number of hydroxyl groups remaining in the obtained polyphenylene ether compound and calculating the decrease from the number of hydroxyl groups in the polyphenylene ether before the substituents were added (before modification). This decrease from the number of hydroxyl groups in the polyphenylene ether before modification is the number of terminal functional groups. The number of hydroxyl groups remaining in a polyphenylene ether compound can be measured by adding a quaternary ammonium salt (tetraethylammonium hydroxide) that associates with hydroxyl groups to a solution of the polyphenylene ether compound and measuring the UV absorbance of the mixed solution.

[0041] The intrinsic viscosity of the polyphenylene ether compound is not particularly limited. Specifically, it is preferably 0.03 to 0.12 dl / g, more preferably 0.04 to 0.11 dl / g, and even more preferably 0.06 to 0.095 dl / g. If the intrinsic viscosity is too low, the molecular weight tends to be low, and it tends to be difficult to obtain low dielectric properties such as a low dielectric loss tangent. On the other hand, if the intrinsic viscosity is too high, the viscosity is high, sufficient fluidity cannot be obtained, and the moldability of the cured product tends to decrease. Therefore, if the intrinsic viscosity of the polyphenylene ether compound is within the above range, excellent heat resistance and moldability of the cured product can be achieved.

[0042] The intrinsic viscosity referred to here is the intrinsic viscosity measured in methylene chloride at 25°C. More specifically, it is the value measured using a viscometer in a 0.18 g / 45 ml methylene chloride solution (at a liquid temperature of 25°C). Examples of such viscometers include the Schott AVS500 Visco System.

[0043] Examples of the polyphenylene ether compounds include the polyphenylene ether compound represented by the following formula (5) and the polyphenylene ether compound represented by the following formula (6). Furthermore, these polyphenylene ether compounds may be used individually or in combination.

[0044] [ka]

[0045] [ka]

[0046] In equations (5) and (6), R9~R 16 R 17 ~R 24 These are independent of each other. That is, R9~R 16 R17 ~R 24 may be the same or different groups even if they are based on the same group. Also, R9 to R 16 as well as R 17 ~R 24 represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. X1 and X2 are each independent. That is, X1 and X2 may be the same group or different groups. X1 and X' represent a substituent having a carbon-carbon unsaturated double bond. A and B each represent a repeating unit represented by the following formula (7) and the following formula (8). Also, in formula (6), Y represents a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms.

[0047] [Chemical formula]

[0048] [Chemical formula] <0,000269>

[0049] In formula (7) and formula (8), m and n each represent 0 to 20. R 25 ~R 28 as well as R 29 ~R 32 are each independent. That is, R 25 ~R 28 as well as R 29 ~R 32 may be the same or different groups even if they are based on the same group. Also, R 25 ~R 28 as well as R 29 ~R 32 represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group.

[0050] The polyphenylene ether compound represented by formula (5) and the polyphenylene ether compound represented by formula (6) are not particularly limited as long as they satisfy the above configuration. Specifically, in formulas (5) and (6), R9 to R 16 R 17 ~R 24 As mentioned above, they are independent of each other. That is, R9~R 16 R 17 ~R 24 These may be the same group or different groups. Also, R9~R 16 R 17 ~R 24 This represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. Among these, hydrogen atoms and alkyl groups are preferred.

[0051] In equations (7) and (8), it is preferable that m and n represent values ​​between 0 and 20, as described above. Furthermore, it is preferable that m and n represent values ​​such that the sum of m and n is between 1 and 30. Therefore, it is more preferable that m represents values ​​between 0 and 20, n represents values ​​between 0 and 20, and the sum of m and n is between 1 and 30. Also, R 25 ~R 28 R 29 ~R 32 These are independent of each other. That is, R 25 ~R 28 R 29 ~R 32 These may be the same group or different groups. Also, R 25 ~R 28 R 29 ~R 32 This represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. Among these, hydrogen atoms and alkyl groups are preferred.

[0052] R9~R 32 This is the same as R5 to R8 in equation (4) above.

[0053] In formula (6) above, Y is a linear, branched, or cyclic hydrocarbon having 20 or fewer carbon atoms, as described above. Examples of Y include the group represented by the following formula (9).

[0054] [ka] In the above formula (9), R 33 and R 34 Each of these independently represents either a hydrogen atom or an alkyl group. Examples of the alkyl group include a methyl group. Examples of the group represented by formula (9) include a methylene group, a methylmethylene group, and a dimethylmethylene group, among which the dimethylmethylene group is preferred.

[0055] In formulas (5) and (6), X1 and X2 are each independent substituents having a carbon-carbon double bond. In the polyphenylene ether compound represented by formula (5) and the polyphenylene ether compound represented by formula (6), X1 and X2 may be the same group or different groups.

[0056] More specific examples of polyphenylene ether compounds represented by formula (5) include, for example, the polyphenylene ether compound represented by the following formula (10).

[0057] [ka]

[0058] More specific examples of the polyphenylene ether compound represented by formula (6) include, for example, the polyphenylene ether compound represented by the following formula (11) and the polyphenylene ether compound represented by the following formula (12).

[0059] [ka]

[0060] [ka]

[0061] In equations (10) to (12) above, m and n are the same as m and n in equations (7) and (8) above. Also, in equations (10) and (11) above, R1 to R3, p and Ar are the same as R1 to R3, p and Ar in equation (1) above. Also, in equations (11) and (12) above, Y is the same as Y in equation (6) above. Also, in equation (12) above, R4 is the same as R4 in equation (2) above.

[0062] The method for synthesizing the polyphenylene ether compound used in this embodiment is not particularly limited, as long as it can synthesize a polyphenylene ether compound having the substituent in the molecule. Specifically, this method includes reacting a polyphenylene ether with a compound in which the substituent and a halogen atom are bonded.

[0063] Examples of compounds in which the substituent and halogen atom are bonded include compounds in which the substituent represented by formulas (1) to (3) is bonded to a halogen atom. Specifically, examples of the halogen atom include chlorine, bromine, iodine, and fluorine atoms, with chlorine being preferred among these. More specifically, examples of compounds in which the substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom include o-chloromethylstyrene, p-chloromethylstyrene, and m-chloromethylstyrene. The compounds in which the substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom may be used alone or in combination of two or more. For example, o-chloromethylstyrene, p-chloromethylstyrene, and m-chloromethylstyrene may be used alone or in combination of two or three.

[0064] The raw material, polyphenylene ether, is not particularly limited as long as it can ultimately synthesize the desired polyphenylene ether compound. Specifically, examples include polyphenylene ethers mainly composed of 2,6-dimethylphenol and at least one of a difunctional phenol and a trifunctional phenol, or poly(2,6-dimethyl-1,4-phenylene oxide). A difunctional phenol is a phenol compound having two phenolic hydroxyl groups in its molecule, such as tetramethylbisphenol A. A trifunctional phenol is a phenol compound having three phenolic hydroxyl groups in its molecule.

[0065] The method for synthesizing the polyphenylene ether compound is as described above. Specifically, the polyphenylene ether described above and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded are dissolved in a solvent and stirred. By doing so, the polyphenylene ether and the compound in which the substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded react to obtain the polyphenylene ether compound used in this embodiment.

[0066] It is preferable to carry out the above reaction in the presence of an alkali metal hydroxide. This is thought to allow the reaction to proceed favorably. This is because the alkali metal hydroxide functions as a dehalogenating agent, specifically a dehydrochlorinating agent. That is, the alkali metal hydroxide removes hydrogen halides from the phenol group of the polyphenylene ether and from the compound in which the substituent having a carbon-carbon unsaturated double bond and the halogen atom are bonded. In this way, the substituent having a carbon-carbon unsaturated double bond is thought to bond to the oxygen atom of the phenol group of the polyphenylene ether in place of the hydrogen atom of the phenol group.

[0067] The alkali metal hydroxide is not particularly limited as long as it can act as a dehalogenating agent, but examples include sodium hydroxide. Furthermore, alkali metal hydroxides are usually used in aqueous solution form, specifically as an aqueous solution of sodium hydroxide.

[0068] The reaction conditions, such as reaction time and reaction temperature, vary depending on the compound in which a substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom, and are not particularly limited as long as the above-mentioned conditions allow the reaction to proceed favorably. Specifically, the reaction temperature is preferably room temperature to 100°C, and more preferably 30 to 100°C. The reaction time is preferably 0.5 to 20 hours, and more preferably 0.5 to 10 hours.

[0069] The solvent used in the reaction is not particularly limited, as long as it can dissolve the polyphenylene ether and the compound in which the substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and does not inhibit the reaction between the polyphenylene ether and the compound in which the substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded. Specifically, examples include toluene.

[0070] The above reaction is preferably carried out in the presence of not only an alkali metal hydroxide but also a phase-transfer catalyst. In other words, the above reaction is preferably carried out in the presence of both an alkali metal hydroxide and a phase-transfer catalyst. It is believed that the above reaction proceeds more favorably by doing so. This is thought to be because the phase-transfer catalyst has the function of incorporating alkali metal hydroxides, is soluble in both the polar solvent phase such as water and the non-polar solvent phase such as an organic solvent, and is a catalyst that can move between these phases. Specifically, when an aqueous sodium hydroxide solution is used as the alkali metal hydroxide and an organic solvent such as toluene, which is immiscible with water, is used as the solvent, even if the aqueous sodium hydroxide solution is added dropwise to the solvent being used in the reaction, the solvent and the aqueous sodium hydroxide solution will separate, and it is thought that the sodium hydroxide will not easily migrate into the solvent. In that case, it is thought that the aqueous sodium hydroxide solution added as the alkali metal hydroxide will not contribute much to promoting the reaction. In contrast, when the reaction is carried out in the presence of an alkali metal hydroxide and a phase-transfer catalyst, the alkali metal hydroxide is incorporated into the phase-transfer catalyst and migrates to the solvent, and the aqueous sodium hydroxide solution is thought to contribute more readily to promoting the reaction. For this reason, the above reaction is thought to proceed more favorably when carried out in the presence of an alkali metal hydroxide and a phase-transfer catalyst.

[0071] The phase transfer catalyst is not particularly limited, but examples include quaternary ammonium salts such as tetra-n-butylammonium bromide.

[0072] The resin composition used in this embodiment preferably contains the polyphenylene ether compound obtained as described above.

[0073] (Hardening agent (B)) The curing agent (B) is not particularly limited as long as it is a curing agent that reacts with the polyphenylene ether compound (A) to contribute to the curing of the resin composition. Examples of the curing agent (B) include allyl compounds, methacrylate compounds, acrylate compounds, acenaphthylene compounds, vinyl compounds, maleimide compounds, cyanate ester compounds, active ester compounds, and benzoxazine compounds.

[0074] The allyl compounds are compounds having an allyl group in their molecule, and examples include triallyl isocyanurate compounds such as triallyl isocyanurate (TAIC), diallyl bisphenol compounds, and diallyl phthalate (DAP).

[0075] The methacrylate compound is a compound having a methacryloyl group in its molecule, and examples include monofunctional methacrylate compounds having one methacryloyl group in their molecule, and polyfunctional methacrylate compounds having two or more methacryloyl groups in their molecule. Examples of the monofunctional methacrylate compound include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Examples of the polyfunctional methacrylate compound include dimethacrylate compounds such as tricyclodecanedimethanol dimethacrylate (DCP).

[0076] The acrylate compound is a compound having an acryloyl group in its molecule, and examples include monofunctional acrylate compounds having one acryloyl group in their molecule, and polyfunctional acrylate compounds having two or more acryloyl groups in their molecule. Examples of the monofunctional acrylate compound include methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. Examples of the polyfunctional acrylate compound include diacrylate compounds such as tricyclodecanedimethanol diacrylate.

[0077] The aforementioned acenaphthylene compound is a compound having an acenaphthylene structure in its molecule. Examples of the aforementioned acenaphthylene compound include acenaphthylene, alkylacenaphthylenes, halogenated acenaphthylenes, and phenylacenaphthylenes. Examples of the aforementioned alkylacenaphthylenes include 1-methylacenaphthylene, 3-methylacenaphthylene, 4-methylacenaphthylene, 5-methylacenaphthylene, 1-ethylacenaphthylene, 3-ethylacenaphthylene, 4-ethylacenaphthylene, and 5-ethylacenaphthylene. Examples of the halogenated acenaphthylenes include 1-chloroacenaphthylene, 3-chloroacenaphthylene, 4-chloroacenaphthylene, 5-chloroacenaphthylene, 1-bromoacenaphthylene, 3-bromoacenaphthylene, 4-bromoacenaphthylene, and 5-bromoacenaphthylene. Examples of the phenylacenaphthylenes include 1-phenylacenaphthylene, 3-phenylacenaphthylene, 4-phenylacenaphthylene, and 5-phenylacenaphthylene. The acenaphthylene compound may be a monofunctional acenaphthylene compound having one acenaphthylene structure in the molecule, as described above, or a polyfunctional acenaphthylene compound having two or more acenaphthylene structures in the molecule.

[0078] The vinyl compound is a compound having a vinyl group in its molecule. Examples of the vinyl compound include monofunctional vinyl compounds (monovinyl compounds) having one vinyl group in their molecule, and polyfunctional vinyl compounds having two or more vinyl groups in their molecule. Examples of the polyfunctional vinyl compound include polyfunctional aromatic vinyl compounds and vinyl hydrocarbon compounds. Examples of the vinyl hydrocarbon compounds include divinylbenzene and polybutadiene compounds.

[0079] The maleimide compound is a compound having a maleimide group in its molecule. Examples of the maleimide compound include a monofunctional maleimide compound having one maleimide group in its molecule, a polyfunctional maleimide compound having two or more maleimide groups in its molecule, and a modified maleimide compound. Examples of the modified maleimide compound include a modified maleimide compound in which part of the molecule is modified with an amine compound, a modified maleimide compound in which part of the molecule is modified with a silicone compound, and a modified maleimide compound in which part of the molecule is modified with both an amine compound and a silicone compound.

[0080] The aforementioned cyanate ester compounds are compounds having a cyanate group in their molecule, and examples include 2,2-bis(4-cyanatephenyl)propane, bis(3,5-dimethyl-4-cyanatephenyl)methane, and 2,2-bis(4-cyanatephenyl)ethane.

[0081] The aforementioned active ester compounds are compounds having highly reactive ester groups in their molecules, and examples include benzenecarboxylic acid active esters, benzenedicarboxylic acid active esters, benzenetricarboxylic acid active esters, benzenetetracarboxylic acid active esters, naphthalenecarboxylic acid active esters, naphthalenedicarboxylic acid active esters, naphthalentricarboxylic acid active esters, naphthalenetetracarboxylic acid active esters, fluorenecarboxylic acid active esters, fluorentricarboxylic acid active esters, and fluorenetetracarboxylic acid active esters.

[0082] The aforementioned benzoxazine compound is a compound having a benzoxazine ring within its molecule, and examples include benzoxazine resins.

[0083] The curing agent (B) is preferably an allyl compound, a methacrylate compound, an acrylate compound, an acenaphthylene compound, a polybutadiene compound, a polyfunctional aromatic vinyl compound, a vinyl hydrocarbon compound, or a maleimide compound. The curing agent (B) may be used alone or in combination of two or more types. Specifically, the curing agent (B) preferably contains at least one selected from the group consisting of an allyl compound, a methacrylate compound, an acrylate compound, an acenaphthylene compound, a polybutadiene compound, a polyfunctional aromatic vinyl compound, a vinyl hydrocarbon compound, and a maleimide compound.

[0084] (Titanate compound filler (C)) The titanate compound filler (C) is not particularly limited as long as it is a filler containing a titanate compound. Examples of the titanate compound filler include titanium oxide particles and titanate metal compound particles. Examples of the titanate metal compound particles include particles containing titanium and having a perovskite crystal structure or a composite perovskite crystal structure. Specific examples of the titanate metal compound particles include barium titanate particles, strontium titanate particles, calcium titanate particles, magnesium titanate particles, zinc titanate particles, lanthanum titanate particles, neodymium titanate particles, and aluminum titanate particles. Among these, strontium titanate particles and calcium titanate particles are preferred as the titanate compound filler (C). The titanate compound filler (C) may be used alone or in combination of two or more types. In other words, the titanate compound filler (C) preferably contains at least one selected from the group consisting of titanium oxide particles, barium titanate particles, strontium titanate particles, calcium titanate particles, magnesium titanate particles, zinc titanate particles, lanthanum titanate particles, neodymium titanate particles, and aluminum titanate particles, and more preferably contains at least one of the strontium titanate particles and calcium titanate particles.

[0085] The titanate compound filler (C) may be a surface-treated filler or an untreated filler, but it is preferable that it be a surface-treated filler. Examples of surface treatment include treatment with coupling agents such as silane coupling agents and titanium coupling agents. In other words, it is preferable that the titanate compound filler (C) is surface-treated with a silane coupling agent or a titanium coupling agent.

[0086] Examples of the silane coupling agent and the titanium coupling agent include coupling agents having at least one functional group selected from the group consisting of vinyl group, styryl group, methacryloyl group, acryloyl group, phenylamino group, isocyanurate group, ureido group, mercapto group, isocyanate group, epoxy group, and acid anhydride group. In other words, the silane coupling agent and the titanium coupling agent are compounds having at least one of vinyl group, styryl group, methacryloyl group, acryloyl group, phenylamino group, isocyanurate group, ureido group, mercapto group, isocyanate group, epoxy group, and acid anhydride group as a reactive functional group, and further having a hydrolyzable group such as a methoxy group or an ethoxy group.

[0087] Examples of silane coupling agents that have a vinyl group include vinyltriethoxysilane and vinyltrimethoxysilane. Examples of silane coupling agents that have a styryl group include p-styryltrimethoxysilane and p-styryltriethoxysilane. Examples of silane coupling agents that have a methacryloyl group include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropylethyldiethoxysilane. Examples of silane coupling agents that have an acryloyl group include 3-acryloxypropyltrimethoxysilane and 3-acryloxypropyltriethoxysilane. Examples of silane coupling agents include those having a phenylamino group, such as N-phenyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltriethoxysilane. Examples of titanium coupling agents include isopropyl(N-ethylaminoethylamino) titanate, isopropyltriisostearoyl titanate, titanium di(dioctyl pyrophosphate) oxyacetate, tetraisopropyl di(dioctyl phosphite) titanate, and neoalkoxytri(pN-(β-aminoethyl)aminophenyl) titanate. These coupling agents may be used individually or in combination of two or more.

[0088] The relative permittivity of the titanate compound filler (C) is preferably 50 or higher, more preferably 60 to 800, and even more preferably 90 to 700. By including a titanate compound filler (C) having such a relative permittivity, a cured product with a high relative permittivity and a low dielectric loss tangent can be suitably obtained.

[0089] The average particle size of the titanate compound filler (C) is not particularly limited. The average particle size of the titanate compound filler (C) also varies depending on the type of titanate compound filler (C), but for example, it is preferably 10 μm or less, more preferably 0.1 to 8 μm, and even more preferably 0.3 to 5 μm. When the titanate compound filler (C) has such a particle size, the dielectric loss tangent of the cured resin composition can be further suppressed while the relative permittivity can be further increased. Here, the average particle size is the volume average particle size, for example, the volume-based cumulative 50% diameter (D50). Specifically, in the particle size distribution measured by a general laser diffraction / scattering method, the particle size (D50) where the cumulative particle size distribution from the small particle size side is 50% (volume basis) can be cited as the volume-based cumulative 50% diameter (volume basis) in the particle size distribution measured by a general laser diffraction / scattering method.

[0090] The specific gravity of the titanate compound filler (C) is not particularly limited. Furthermore, the specific gravity of the titanate compound filler (C) varies depending on the type of titanate compound filler (C), but is typically between 3 and 7 g / cm³. 3 It is preferable that this be the case.

[0091] (Silica Filler (D)) The silica filler (D) is not particularly limited and includes, for example, silica fillers commonly used as fillers in resin compositions. The silica filler is not particularly limited and includes, for example, crushed silica, spherical silica, and silica particles.

[0092] The silica filler (D), like the titanate compound filler (C), may be a surface-treated filler or an untreated filler. Examples of surface treatments include treatment with coupling agents such as silane coupling agents and titanium coupling agents. The silane coupling agent and titanium coupling agent are not particularly limited, but examples include coupling agents similar to those used in the surface treatment of the titanate compound filler (C).

[0093] The average particle size of the silica filler (D) is not particularly limited, but is preferably 0.1 to 8 μm, and more preferably 0.3 to 5 μm. Here, the average particle size is the volume-average particle diameter as described above, and examples include the volume-based cumulative 50% (D50) diameter in laser diffraction scattering particle size distribution measurement. The specific gravity of the silica filler (D) is not particularly limited, and is 2 to 3 g / cm³. 3 It is preferable that this be the case.

[0094] (Content) The content ratio of the titanate compound filler (C) to the silica filler (D) is preferably 10:90 to 90:10 by mass, preferably 15:85 to 85:15, and more preferably 20:80 to 80:20. That is, the content of the titanate compound filler (C) is preferably 10 to 90 parts by mass, preferably 15 to 85 parts by mass, and more preferably 20 to 80 parts by mass, per 100 parts by mass of the total of the titanate compound filler (C) and the silica filler (D).

[0095] The content of the titanate compound filler (C) is preferably 20 to 300 parts by mass, more preferably 25 to 250 parts by mass, and even more preferably 30 to 200 parts by mass, based on 100 parts by mass of the total of the polyphenylene ether compound (A) and the curing agent (B).

[0096] When the content of the titanate compound filler (C) is within the above range relative to the sum of the titanate compound filler (C) and the silica filler (D), and also relative to the sum of the polyphenylene ether compound (A) and the curing agent (B), the resulting resin composition and cured prepreg have a high dielectric constant and a low dielectric loss tangent. Furthermore, if the total content of the titanate compound filler (C) and the silica filler (D) is too high, the melt viscosity of the resulting resin composition tends to become too high, reducing its moldability. When the content of the titanate compound filler (C) is within the above range, excellent moldability is obtained, and the resulting resin composition and cured prepreg preferably have a high dielectric constant and a low dielectric loss tangent.

[0097] The content of the polyphenylene ether compound (A) is preferably 30 to 90 parts by mass, and more preferably 40 to 80 parts by mass, based on 100 parts by mass of the total of the polyphenylene ether compound (A) and the curing agent (B). That is, the content of the curing agent (B) is preferably 10 to 70 parts by mass, and more preferably 20 to 60 parts by mass, based on 100 parts by mass of the total of the polyphenylene ether compound (A) and the curing agent (B). If the content of the curing agent is too low or too high, it tends to be difficult to obtain a cured product of a suitable resin composition, for example, it tends to be difficult to obtain a resin composition with excellent heat resistance. Therefore, when the content of the polyphenylene ether compound (A) and the curing agent (B) are within the above ranges, a cured product with a high dielectric constant and a low dielectric loss tangent can be suitably obtained.

[0098] (Other ingredients) The resin composition may optionally contain components other than the polyphenylene ether compound (A), the curing agent (B), the titanate compound filler (C), and the silica filler (D), as long as the effects of the present invention are not impaired. Other components contained in the resin composition according to this embodiment may further include additives such as reaction initiators, reaction accelerators, catalysts, polymerization retarders, polymerization inhibitors, dispersants, leveling agents, coupling agents, defoamers, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, dyes and pigments, and lubricants.

[0099] As described above, the resin composition according to this embodiment may contain a reaction initiator. Even if the resin composition does not contain a reaction initiator, the curing reaction can proceed. However, depending on the process conditions, it may be difficult to raise the temperature until curing proceeds, so a reaction initiator may be added. The reaction initiator is not particularly limited as long as it can promote the curing reaction of the resin composition, and examples include peroxides and organic azo compounds. Examples of peroxides include dicumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexine, and benzoyl peroxide. Examples of organic azo compounds include azobisisobutyronitrile. In addition, metal carboxylate salts can be used in combination as needed. By doing so, the curing reaction can be further promoted. Among these, α,α'-bis(t-butylperoxy-m-isopropyl)benzene is preferably used. α,α'-bis(t-butylperoxy-m-isopropyl)benzene has a relatively high reaction initiation temperature, which can suppress the acceleration of the curing reaction at times when curing is not required, such as during prepreg drying, thereby suppressing the deterioration of the shelf life of the resin composition. Furthermore, because α,α'-bis(t-butylperoxy-m-isopropyl)benzene has low volatility, it does not volatilize during prepreg drying or storage, resulting in good stability. The reaction initiator may be used alone or in combination of two or more types.

[0100] As described above, the resin composition according to this embodiment may contain a coupling agent. The coupling agent may be contained in the resin composition, or it may be contained in a coupling agent that has been pre-surface-treated on the titanate compound filler (C) and the silica filler (D) contained in the resin composition. Among these, it is preferable that the coupling agent be contained in a coupling agent that has been pre-surface-treated on the titanate compound filler (C) and the silica filler (D), and it is even more preferable that the coupling agent be contained in a coupling agent that has been pre-surface-treated on the titanate compound filler (C) and the silica filler (D), and furthermore, that the resin composition also contains the coupling agent. In the case of a prepreg, the prepreg may contain the coupling agent that has been pre-surface-treated on the fibrous substrate. Examples of the coupling agent include those similar to the coupling agent used when surface-treating the titanate compound filler (C) and the silica filler (D) as described above.

[0101] As described above, the resin composition according to this embodiment may contain a flame retardant. By including a flame retardant, the flame retardancy of the cured resin composition can be enhanced. The flame retardant is not particularly limited. Specifically, in fields where halogen-based flame retardants such as brominated flame retardants are used, for example, ethylene dipentabromobenzene, ethylene bistetrabromoimide, decabromodiphenyl oxide, tetradecabromodiphenoxybenzene, and bromostyrene compounds that react with the polymerizable compound are preferred, each having a melting point of 300°C or higher. It is believed that by using a halogen-based flame retardant, the desorption of halogens at high temperatures can be suppressed, thereby suppressing a decrease in heat resistance. In addition, in fields where halogen-free is required, a phosphorus-containing flame retardant (phosphorus-based flame retardant) may be used. The phosphorus-based flame retardant is not particularly limited, but examples include phosphate ester-based flame retardants, phosphazene-based flame retardants, bis-diphenylphosphine oxide-based flame retardants, and phosphinate-based flame retardants. Specific examples of phosphate ester-based flame retardants include condensed phosphate esters of dixylenyl phosphate. Specific examples of phosphazene-based flame retardants include phenoxyphosphazene. Specific examples of bis-diphenylphosphine oxide-based flame retardants include xylylene bis-diphenylphosphine oxide. Specific examples of phosphinate-based flame retardants include, for example, phosphinate metal salts of aluminum dialkylphosphinate. The flame retardants described above may be used individually or in combination of two or more.

[0102] (Application) The aforementioned resin composition is used in the manufacture of prepregs, as will be described later. Furthermore, the resin composition is used in forming resin layers in resin-coated metal foils and resin-coated films, and insulating layers in metal-clad laminates and wiring boards.

[0103] The cured product of the resin composition preferably has a relative permittivity of 3.5 to 7 at a frequency of 10 GHz, and more preferably 3.5 to 6.5. Furthermore, the cured product of the resin composition preferably has a dielectric loss tangent of 0.01 or less at a frequency of 10 GHz, more preferably 0.005 or less, and even more preferably 0.003 or less. Here, the relative permittivity and dielectric loss tangent refer to the relative permittivity and dielectric loss tangent of the cured product of the resin composition at a frequency of 10 GHz, and examples include the relative permittivity and dielectric loss tangent of the cured product of the resin composition at a frequency of 10 GHz measured by the cavity resonator perturbation method. Thus, the resin composition yields a cured product with a high relative permittivity and a low dielectric loss tangent. For this reason, the resin composition is suitably used to form an insulating layer provided in a multilayer wiring board. The total number of wirings arranged between the insulating layers and on the insulating layers (number of wiring layers) in the multilayer wiring board is not particularly limited, but for example, it is more preferably 10 layers or more, and even more preferably 12 layers or more. This allows for higher density wiring in multilayer wiring boards, enabling faster signal transmission and reduced signal transmission losses even in such multilayer wiring boards. In the case of such wiring boards, whether they have conductive through-holes, conductive vias, or both, faster signal transmission and reduced signal transmission losses can be achieved. Specifically, the resin composition is preferably used to form insulating layers between wiring layers in a wiring board having 10 or more wiring layers.

[0104] The multilayer wiring board is not particularly limited, but it is preferable to include a wiring pattern with small wiring distances and wiring widths.

[0105] The multilayer wiring board is not particularly limited, but for example, it is preferable that a portion of the wiring patterns in the multilayer wiring board include wiring patterns with a wiring distance of 380 μm or less, and more preferably that it includes wiring patterns with a wiring distance of 300 μm or less. That is, the resin composition is suitably used when manufacturing a wiring board that includes a portion of wiring patterns with such small wiring distances. Even with a wiring board that includes a portion of wiring patterns with a wiring distance of 380 μm or less, it is possible to achieve high-speed signal transmission and reduce signal transmission losses. Here, the wiring distance is the distance between adjacent wirings.

[0106] The multilayer wiring board is not particularly limited, but for example, it is preferable that a portion of the wiring pattern in the multilayer wiring board includes a wiring pattern with a wiring width of 250 μm or less, and more preferably includes a wiring pattern with a wiring width of 200 μm or less. That is, the resin composition is suitably used when manufacturing a wiring board that includes a portion of wiring patterns with such small wiring widths. Even with a wiring board that includes a portion of wiring patterns with a wiring width of 250 μm or less, it is possible to achieve high-speed signal transmission and reduce signal transmission losses. Here, the wiring width is the distance perpendicular to the longitudinal direction of the wiring.

[0107] The multilayer wiring board may have conductor through-holes and vias formed in part for electrically connecting the multilayer wiring layers, as needed. The multilayer wiring board may have only conductor through-holes, only vias, or both. Furthermore, the conductor through-holes and vias may be formed as needed, and their number may be one or multiple. The conductor through-holes and vias are not particularly limited, but it is preferable that the via diameter is 300 μm or less. That is, as the multilayer wiring board, for example, a wiring board having a wiring pattern in which conductor through-holes with a via diameter of 300 μm or less and vias with a via diameter of 300 μm or less are partially formed is preferred. Furthermore, as the multilayer wiring board, a wiring board having a wiring pattern in which the distance between conductor through-holes and vias (e.g., distance between conductor through-holes, distance between vias, distance between conductor through-holes and vias) is 300 μm or less is more preferred.

[0108] (Manufacturing method) The method for producing the resin composition is not particularly limited as long as it can produce the resin composition, and examples include a method of mixing the polyphenylene ether compound (A), the curing agent (B), the titanate compound filler (C), and the silica filler (D) in predetermined amounts. Furthermore, when obtaining a varnish-like composition containing an organic solvent, the method described later may be used.

[0109] Furthermore, by using the resin composition according to this embodiment, prepregs, metal-clad laminates, wiring boards, resin-coated metal foils, and resin-coated films can be obtained as follows.

[0110] [Prepreg] Figure 1 is a schematic cross-sectional view showing an example of prepreg 1 according to an embodiment of the present invention.

[0111] As shown in Figure 1, the prepreg 1 according to this embodiment comprises the resin composition or a semi-cured product 2 of the resin composition and a fibrous base material 3. This prepreg 1 comprises the resin composition or a semi-cured product 2 of the resin composition and a fibrous base material 3 present in the resin composition or the semi-cured product 2 of the resin composition.

[0112] In this embodiment, a 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, a semi-cured product is a resin composition that has been partially cured (stage B). For example, when a resin composition is heated, its viscosity gradually decreases at first, and then curing begins, causing the viscosity to gradually increase. In such a case, a semi-cured state would be the state between the time the viscosity begins to increase and before it is completely cured.

[0113] The prepreg obtained using the resin composition according to this embodiment may include a semi-cured product of the resin composition as described above, or it may include the uncured resin composition itself. That is, it may be a prepreg comprising a semi-cured product of the resin composition (the resin composition in stage B) and a fibrous substrate, or it may be a prepreg comprising the uncured resin composition (the resin composition in stage A) and a fibrous substrate. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried.

[0114] When manufacturing the prepreg, the resin composition 2 is often prepared in a varnish-like form for impregnation into the fibrous substrate 3, which is the base material for forming the prepreg. That is, the resin composition 2 is usually a resin varnish prepared in a varnish-like form. Such a varnish-like resin composition (resin varnish) is prepared, for example, as follows.

[0115] First, each component that can be dissolved in an organic solvent is added to the organic solvent and dissolved. Heating may be used as needed during this process. Then, components that cannot be dissolved in the organic solvent are added as needed, and the mixture is dispersed using a ball mill, bead mill, planetary mixer, roll mill, etc., until a predetermined dispersion state is reached, thereby preparing a varnish-like resin composition. The organic solvent used here is not particularly limited as long as it dissolves the polyphenylene ether compound (A) and the curing agent (B), etc., and does not inhibit the curing reaction. Specifically, examples include toluene and methyl ethyl ketone (MEK).

[0116] Specific examples of the fibrous substrate include glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. When glass cloth is used, a laminate with excellent mechanical strength can be obtained, and flattened glass cloth is particularly preferred. Specific examples of the flattening process include a method in which the glass cloth is continuously pressed with a press roll at an appropriate pressure to flatten the yarn. The thickness of the fibrous substrate commonly used is, for example, 0.01 mm to 0.3 mm. The glass fibers constituting the glass cloth are not particularly limited, but examples include Q glass, NE glass, E glass, S glass, T glass, L glass, and L2 glass. The surface of the fibrous substrate may also be surface-treated with a silane coupling agent. The silane coupling agent is not particularly limited, but examples include a silane coupling agent having at least one group selected from the group consisting of vinyl group, acryloyl group, methacryloyl group, styryl group, amino group, and epoxy group in its molecule.

[0117] The fibrous substrate preferably has a relative permittivity of 3.5 to 7 at a frequency of 10 GHz, and more preferably 3.5 to 6.5. Furthermore, the difference between the relative permittivity of the cured resin composition at a frequency of 10 GHz and the relative permittivity of the fibrous substrate at a frequency of 10 GHz is preferably 0 to 0.3, more preferably 0 to 0.2, and even more preferably 0. When the relative permittivity of the fibrous substrate is within the above range, the occurrence of skew in the finally obtained wiring board can be suppressed. Therefore, the deterioration of signal quality due to skew in the wiring board can be suppressed. Furthermore, the dielectric loss tangent of the fibrous substrate preferably has a dielectric loss tangent of 0.0002 to 0.01 at a frequency of 10 GHz, and more preferably 0.0005 to 0.008. The relative permittivity of the cured prepreg at a frequency of 10 GHz is preferably 3.5 to 7, and more preferably 3.5 to 6.5.

[0118] The dielectric constant (Dk) and dielectric loss tangent (Df) of the fibrous substrate were obtained using the following measurement method. First, a substrate (copper-clad laminate) was prepared so that the resin content per 100% by mass of prepreg was 60% by mass. The copper foil was removed from the prepared copper-clad laminate to obtain a sample for evaluating the dielectric constant (Dk) and dielectric loss tangent (Df). The Dk and Df of the obtained sample at a frequency of 10 GHz were measured using a network analyzer (N5230A manufactured by Agilent Technologies, Inc.) with the cavity resonator perturbation method. From the Dk and Df values ​​of the obtained sample (cured prepreg), the Dk and Df of the fibrous substrate were calculated based on the volume fraction of the fibrous substrate and the resin composition used to prepare the substrate, using the cavity resonator perturbation method to measure the Dk and Df of the cured resin composition at a frequency of 10 GHz.

[0119] The method for manufacturing the prepreg is not particularly limited as long as it can produce the prepreg. Specifically, when manufacturing the prepreg, the resin composition according to this embodiment is often prepared in a varnish-like state as described above and used as a resin varnish.

[0120] A specific method for manufacturing the prepreg 1 is to impregnate a fibrous substrate 3 with the resin composition 2, for example, a resin composition 2 prepared in the form of a varnish, and then dry it. The resin composition 2 is impregnated into the fibrous substrate 3 by immersion, coating, etc. It is also possible to repeat the impregnation process multiple times as needed. Furthermore, by repeating the impregnation process using multiple resin compositions with different compositions and concentrations, it is possible to adjust the final composition and amount of impregnation to the desired level.

[0121] The fibrous substrate 3 impregnated with the resin composition (resin varnish) 2 is heated under desired heating conditions, for example, at 40°C to 180°C for 1 minute to 10 minutes. Heating yields a prepreg 1 in either a pre-cured state (Stage A) or a semi-cured state (Stage B). Heating can also cause organic solvents to volatilize from the resin varnish, reducing or removing them.

[0122] The resin composition according to this embodiment is a resin composition that yields a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. Therefore, a prepreg comprising this resin composition or a semi-cured product of this resin composition is a prepreg that yields a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. Furthermore, this prepreg can suitably manufacture a wiring board having an insulating layer containing a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. Moreover, the cured product obtained from the resin composition not only has a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance, but also a low coefficient of thermal expansion. Thus, a cured product with a low coefficient of thermal expansion is obtained as the cured product of the prepreg. Therefore, a wiring board obtained from this prepreg is equipped with an insulating layer that has a high relative permittivity, a low dielectric loss tangent, excellent heat resistance, and a low coefficient of thermal expansion.

[0123] [Metal-clad laminate] Figure 2 is a schematic cross-sectional view showing an example of a metal-clad laminate 11 according to an embodiment of the present invention.

[0124] As shown in Figure 2, the metal-clad laminate 11 according to this embodiment comprises an insulating layer 12 containing a cured product of the resin composition and a metal foil 13 provided on the insulating layer 12. Examples of the metal-clad laminate 11 include a metal-clad laminate composed of an insulating layer 12 containing a cured product of the prepreg 1 shown in Figure 1 and a metal foil 13 laminated together with the insulating layer 12. The insulating layer 12 may be made of a cured product of the resin composition or a cured product of the prepreg. The thickness of the metal foil 13 is not particularly limited and varies depending on the performance required of the final printed circuit board. The thickness of the metal foil 13 can be set appropriately according to the desired purpose, and is preferably, for example, 0.2 to 70 μm. Examples of the metal foil 13 include copper foil and aluminum foil, and if the metal foil is thin, it may be a carrier-equipped copper foil with a release layer and carrier to improve handling.

[0125] The method for manufacturing the metal-clad laminate 11 is not particularly limited as long as it can be manufactured. Specifically, one method is to manufacture the metal-clad laminate 11 using the prepreg 1. This method involves stacking one or more prepreg 1 sheets, further stacking metal foil 13 such as copper foil on both the top and bottom surfaces or one or both surfaces, and then heat-pressure-molding the metal foil 13 and the prepreg 1 to laminate and integrate them, thereby producing a laminate 11 with metal foil on both sides or one side. In other words, the metal-clad laminate 11 is obtained by laminating the metal foil 13 onto the prepreg 1 and then heat-pressure-molding it. The heating and pressing conditions can be appropriately set depending on the thickness of the metal-clad laminate 11 and the type of resin composition contained in the prepreg 1. For example, the temperature can be 170-230°C, the pressure 2-4 MPa, and the time 60-150 minutes. The metal-clad laminate may also be manufactured without using prepreg. For example, one method involves applying a varnish-like resin composition onto a metal foil to form a layer containing the resin composition on the metal foil, and then heating and pressurizing it.

[0126] The resin composition according to this embodiment is a resin composition that yields a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. Therefore, a metal-clad laminate having an insulating layer containing the cured product of this resin composition is a metal-clad laminate having an insulating layer containing a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. Furthermore, this metal-clad laminate can suitably manufacture a wiring board having an insulating layer containing a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. Moreover, the cured product obtained from the resin composition not only has a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance, but also a low coefficient of thermal expansion. Thus, a wiring board obtained using a metal-clad laminate having an insulating layer containing the cured product of the resin composition has an insulating layer that is not only high relative permittivity and low dielectric loss tangent, but also excellent heat resistance and a low coefficient of thermal expansion.

[0127] [Wiring board] Figure 3 is a schematic cross-sectional view showing an example of a wiring board 21 according to an embodiment of the present invention.

[0128] The wiring board 21 according to this embodiment comprises an insulating layer 12 containing a cured product of the resin composition and wiring 14 provided on the insulating layer 12. An example of the wiring board 21 is a wiring board comprising the insulating layer 12 and wiring 14 arranged to contact both sides thereof, as shown in Figure 3. Alternatively, the wiring board may be one in which the wiring is in contact with only one surface of the insulating layer. An example of the wiring board 21 is a wiring board composed of an insulating layer 12 obtained by curing the prepreg 1 shown in Figure 1, and wiring 14 laminated together with the insulating layer 12 and formed by partially removing the metal foil 13. Furthermore, the insulating layer 12 may be made of a cured product of the resin composition or of a cured product of the prepreg.

[0129] The method for manufacturing the wiring board 21 is not particularly limited as long as it can be manufactured. Specifically, a method for manufacturing the wiring board 21 using the prepreg 1 is one example. For example, this method involves etching the metal foil 13 on the surface of the metal-clad laminate 11 manufactured as described above to form wiring, thereby manufacturing a wiring board 21 in which wiring is provided as a circuit on the surface of the insulating layer 12. That is, the wiring board 21 is obtained by partially removing the metal foil 13 on the surface of the metal-clad laminate 11 to form a circuit. In addition to the above method, other methods for circuit formation include, for example, circuit formation by the semi-additive process (SAP) or the modified semi-additive process (MSAP). The wiring board 21 is a wiring board comprising an insulating layer 12 containing a cured material that has a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. Furthermore, the cured product obtained from the resin composition has a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance, as well as a low coefficient of thermal expansion. Therefore, the wiring board is equipped with an insulating layer that has a high relative permittivity, a low dielectric loss tangent, excellent heat resistance, and a low coefficient of thermal expansion.

[0130] The wiring board may be a wiring board having one layer of wiring and one layer of insulating layer, or, as shown in Figure 3, a wiring board 21 having two layers of wiring and one layer of insulating layer. Alternatively, as shown in Figure 4, the wiring board may be a multilayer wiring board 31 having multiple layers of both wiring and insulating layer. In this multilayer wiring board 31, the wiring 14 may be arranged between the insulating layer 12 or on the surface of the insulating layer 12. As described above, the resin composition yields a cured product with a high dielectric constant, low dielectric loss tangent, and excellent heat resistance, making it suitable for use in forming the insulating layer provided in such a multilayer wiring board 31. That is, since the wiring board includes an insulating layer containing a cured product of the resin composition, it is preferable that the wiring board be a multilayer wiring board. Figure 4 is a schematic cross-sectional view showing another example of a wiring board 31 according to an embodiment of the present invention.

[0131] As described above, the multilayer wiring board 31 is a wiring board in which both the wiring 14 and the insulating layer 12 are multiple layers. The total number of wiring 14 arranged between the insulating layer 12 and the insulating layer 12 and the wiring 14 arranged on the insulating layer 12 (number of wiring layers, i.e., N layers) is not particularly limited, but is preferably 10 or more, and preferably 12 or more. This allows for higher density wiring in the multilayer wiring board, enabling faster signal transmission and reduced signal transmission losses even with such a multilayer wiring board. With such a wiring board, whether the multilayer wiring board has conductive through-holes, conductive vias, or both, it is possible to achieve faster signal transmission and reduce signal transmission losses. Furthermore, in the multilayer wiring board, it is more preferable that the wiring distance and wiring width are within the range described above.

[0132] The multilayer wiring board 31 is manufactured, for example, as follows: The prepreg is laminated on at least one side of a wiring board 21 as shown in Figure 3, and if necessary, metal foil is laminated on top of it, and then heated and pressed. Wiring is formed on the metal foil on the surface of the laminate obtained in this way by etching or the like. In this way, a multilayer wiring board 31 as shown in Figure 4 can be manufactured.

[0133] [Metal foil with resin coating] Figure 5 is a schematic cross-sectional view showing an example of a resin-coated metal foil 41 according to this embodiment.

[0134] As shown in Figure 5, the resin-coated metal foil 41 according to this embodiment comprises a resin layer 42 containing the resin composition or a semi-cured product of the resin composition, and a metal foil 13. This resin-coated metal foil 41 has the metal foil 13 on the surface of the resin layer 42. That is, this resin-coated metal foil 41 comprises the resin layer 42 and the metal foil 13 laminated together with the resin layer 42. In addition, the resin-coated metal foil 41 may have other layers between the resin layer 42 and the metal foil 13.

[0135] The resin layer 42 may contain a semi-cured product of the resin composition as described above, or it may contain the uncured resin composition. That is, the resin-coated metal foil 41 may comprise a resin layer containing a semi-cured product of the resin composition (the resin composition in stage B) and a metal foil, or it may comprise a resin layer containing the uncured resin composition (the resin composition in stage A) and a metal foil. Furthermore, the resin layer may contain the resin composition or a semi-cured product of the resin composition, and may or may not contain a fibrous substrate. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried. Furthermore, the fibrous substrate may be the same as the fibrous substrate of the prepreg.

[0136] The aforementioned metal foil can be any metal foil used in metal-clad laminates or resin-coated metal foils without limitation. Examples of such metal foils include copper foil and aluminum foil.

[0137] The resin-coated metal foil 41 may be provided with a cover film or the like, if necessary. Providing a cover film can prevent the incorporation of foreign matter. The cover film is not particularly limited, but examples include polyolefin film, polyester film, polymethylpentene film, and films formed by providing a release agent layer on these films.

[0138] The method for producing the resin-coated metal foil 41 is not particularly limited as long as it can produce the resin-coated metal foil 41. Examples of methods for producing the resin-coated metal foil 41 include applying the varnish-like resin composition (resin varnish) onto the metal foil 13 and heating it. The varnish-like resin composition is applied onto the metal foil 13, for example, by using a bar coater. The applied resin composition is heated, for example, at a temperature of 40°C to 180°C for 0.1 minutes to 10 minutes. The heated resin composition is formed on the metal foil 13 as an uncured resin layer 42. The heating can cause the organic solvent to volatilize from the resin varnish, reducing or removing the organic solvent.

[0139] The resin composition according to this embodiment is a resin composition that yields a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. Therefore, a resin-coated metal foil comprising a resin layer containing this resin composition or a semi-cured product of this resin composition is a resin-coated metal foil comprising a resin layer that yields a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. Furthermore, this resin-coated metal foil can be used in the manufacture of a wiring board having an insulating layer containing a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. For example, a multilayer wiring board can be manufactured by laminating it on top of a wiring board. A wiring board obtained using such a resin-coated metal foil is obtained that has an insulating layer containing a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. Moreover, a cured product obtained from the resin composition is obtained that not only has a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance, but also a low coefficient of thermal expansion. Therefore, a wiring board obtained using a resin-coated metal foil comprising the resin composition or a resin layer containing a semi-cured product of the resin composition has not only a high relative permittivity and a low dielectric loss tangent, but also an insulating layer with excellent heat resistance and a low coefficient of thermal expansion.

[0140] [Resin-coated film] Figure 6 is a schematic cross-sectional view showing an example of a resin-coated film 51 according to this embodiment.

[0141] As shown in Figure 6, the resin-coated film 51 according to this embodiment comprises a resin layer 52 containing the resin composition or a semi-cured product of the resin composition, and a support film 53. This resin-coated film 51 comprises the resin layer 52 and a support film 53 laminated together with the resin layer 52. The resin-coated film 51 may also have other layers between the resin layer 52 and the support film 53.

[0142] The resin layer 52 may contain a semi-cured product of the resin composition as described above, or it may contain the uncured resin composition. That is, the resin-coated film 51 may comprise a resin layer containing a semi-cured product of the resin composition (the resin composition of stage B) and a support film, or it may comprise a resin layer containing the uncured resin composition (the resin composition of stage A) and a support film. Furthermore, the resin layer may contain the resin composition or a semi-cured product of the resin composition, and may or may not contain a fibrous substrate. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried. Furthermore, the fibrous substrate may be the same as the fibrous substrate of the prepreg.

[0143] The support film 53 can be any support film used for resin-coated films without limitation. Examples of such support films include polyester film, polyethylene terephthalate (PET) film, polyimide film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, polyamide film, polycarbonate film, and electrically insulating films such as polyarylate film.

[0144] The resin-coated film 51 may be provided with a cover film or the like, if necessary. Providing a cover film can prevent the incorporation of foreign matter. The cover film is not particularly limited, but examples include polyolefin film, polyester film, and polymethylpentene film.

[0145] The support film and the cover film may be subjected to surface treatments such as matte treatment, corona treatment, release treatment, and roughening treatment, as needed.

[0146] The method for manufacturing the resin-coated film 51 is not particularly limited as long as it can be manufactured. Examples of methods for manufacturing the resin-coated film 51 include applying the varnish-like resin composition (resin varnish) onto a support film 53 and heating it. The varnish-like resin composition is applied onto the support film 53, for example, by using a bar coater. The applied resin composition is heated, for example, at a temperature of 40°C to 180°C for 0.1 minutes to 10 minutes. The heated resin composition is formed on the support film 53 as an uncured resin layer 52. The heating can cause organic solvents to volatilize from the resin varnish, thereby reducing or removing the organic solvents.

[0147] The resin composition according to this embodiment is a resin composition that yields a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. Therefore, a resin-coated film comprising a resin layer containing this resin composition or a semi-cured product of this resin composition is a resin-coated film comprising a resin layer that yields a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. This resin-coated film can be suitably used in the manufacture of a wiring board having an insulating layer containing a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. For example, a multilayer wiring board can be manufactured by laminating it onto a wiring board and then peeling off the support film, or by laminating it onto a wiring board after peeling off the support film. A wiring board obtained using such a resin-coated film has an insulating layer containing a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. Furthermore, a cured product obtained from the resin composition not only has a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance, but also a low coefficient of thermal expansion. Therefore, a wiring board obtained using a resin-coated film comprising the resin composition or a resin layer containing a semi-cured product of the resin composition has not only a high relative permittivity and a low dielectric loss tangent, but also an insulating layer with excellent heat resistance and a low coefficient of thermal expansion.

[0148] According to the present invention, it is possible to provide a resin composition that yields a cured product with a high relative permittivity, a low dielectric loss tangent, and excellent heat resistance. Furthermore, according to the present invention, it is possible to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that can be obtained using the resin composition.

[0149] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited thereto. [Examples]

[0150] [Examples 1-9 and Comparative Examples 1-5] In this embodiment, each component used in preparing the prepreg will be described.

[0151] (Polyphenylene ether compound (A): PPE) Modified PPE-1: A polyphenylene ether compound having a vinyl benzyl group (ethenyl benzyl group) at its terminus (a modified polyphenylene ether compound obtained by reacting polyphenylene ether with chloromethylstyrene).

[0152] Specifically, it is a modified polyphenylene ether compound obtained by the following reaction.

[0153] First, 200 g of polyphenylene ether (SA90, manufactured by SABIC Innovative Plastics, with 2 terminal hydroxyl groups and a weight-average molecular weight Mw1700), 30 g of a mixture of p-chloromethylstyrene and m-chloromethylstyrene in a mass ratio of 50:50 (chloromethylstyrene: CMS, manufactured by Tokyo Chemical Industry Co., Ltd.), 1.227 g of tetra-n-butylammonium bromide as a phase transfer catalyst, and 400 g of toluene were charged into a 1-liter three-necked flask equipped with a temperature controller, a stirrer, a cooling system, and a dropping funnel, and the mixture was stirred. The mixture was then stirred until the polyphenylene ether, chloromethylstyrene, and tetra-n-butylammonium bromide dissolved in the toluene. During this process, the mixture was gradually heated until the liquid temperature reached 75°C. Then, an aqueous sodium hydroxide solution (20 g sodium hydroxide / 20 g water) was added dropwise to the solution over 20 minutes as an alkali metal hydroxide. The mixture was then stirred at 75°C for 4 hours. Next, the contents of the flask were neutralized with 10% by mass hydrochloric acid, and then a large amount of methanol was added. This caused a precipitate to form in the liquid in the flask, that is, the products contained in the reaction mixture in the flask were re-precipitated. This precipitate was then removed by filtration, washed three times with a methanol-water mixture in a mass ratio of 80:20, and then dried under reduced pressure at 80°C for 3 hours.

[0154] The obtained solid, 1 The compound was analyzed by 1H-NMR (400 MHz, CDCl3, TMS). NMR analysis revealed a peak at 5-7 ppm originating from a vinylbenzyl group (ethenylbenzyl group). This confirmed that the obtained solid is a modified polyphenylene ether compound having a vinylbenzyl group (ethenylbenzyl group) as a substituent at the molecular terminus. Specifically, it was confirmed to be an ethenylbenzyl polyphenylene ether. This obtained modified polyphenylene ether compound is represented by formula (11), where Y in formula (11) is a dimethylmethylene group (represented by formula (9), where R in formula (9) is... 33 and R 34It was a modified polyphenylene ether compound in which (the group is a methyl group), Ar is a phenylene group, R1 to R3 are hydrogen atoms, and p is 1.

[0155] Furthermore, the number of terminal functional groups in the modified polyphenylene ether was measured as follows.

[0156] First, the modified polyphenylene ether was accurately weighed. Let the weight be X (mg). Then, this weighed modified polyphenylene ether was dissolved in 25 mL of methylene chloride, and 100 μL of an ethanol solution of 10% by mass of tetraethylammonium hydroxide (TEAH) (TEAH:ethanol (volume ratio) = 15:85) was added to the solution. The absorbance (Abs) at 318 nm was then measured using a UV spectrophotometer (UV-1600, Shimadzu Corporation). From the measurement results, the number of terminal hydroxyl groups of the modified polyphenylene ether was calculated using the following formula.

[0157] Residual OH amount (μmol / g) = [(25×Abs) / (ε×OPL×X)]×10 6 Here, ε represents the extinction coefficient, which is 4700 L / mol·cm. OPL is the cell path length, which is 1 cm.

[0158] Furthermore, the calculated amount of residual OH (number of terminal hydroxyl groups) in the modified polyphenylene ether was almost zero, indicating that the hydroxyl groups of the polyphenylene ether before modification were almost completely modified. From this, it was found that the decrease from the number of terminal hydroxyl groups of the polyphenylene ether before modification corresponds to the number of terminal hydroxyl groups of the polyphenylene ether before modification. In other words, the number of terminal hydroxyl groups of the polyphenylene ether before modification corresponds to the number of terminal functional groups of the modified polyphenylene ether. That is, the number of terminal functional groups was 2.

[0159] Furthermore, the intrinsic viscosity (IV) of modified polyphenylene ether was measured in methylene chloride at 25°C. Specifically, the intrinsic viscosity (IV) of modified polyphenylene ether was measured using a viscometer (Schott AVS500 Visco System) with a 0.18 g / 45 ml solution of modified polyphenylene ether in methylene chloride (at a liquid temperature of 25°C). As a result, the intrinsic viscosity (IV) of modified polyphenylene ether was 0.086 dl / g.

[0160] Furthermore, the molecular weight distribution of the modified polyphenylene ether was measured using GPC. The weight-average molecular weight (Mw) was then calculated from the obtained molecular weight distribution. The result showed that Mw was 1900.

[0161] Modified PPE-2: A modified polyphenylene ether obtained by modifying the terminal hydroxyl groups of polyphenylene ether with methacryloyl groups (represented by formula (12) above, where Y in formula (12) is a dimethylmethylene group (represented by formula (9), where R in formula (9) is...) 33 and R 34 A modified polyphenylene ether compound in which the terminal functional group is a methyl group (SA9000, manufactured by SABIC Innovative Plastics, with a weight-average molecular weight of Mw1700 and 2 terminal functional groups).

[0162] (Hardening agent (B)) DVB: Divinylbenzene (DVB810 manufactured by Nippon Steel & Sumitomo Metal Corporation) TAIC: Triallyl isocyanurate (TAIC manufactured by Nippon Chemical Corporation) Asenaphthylene: Asenaphthylene manufactured by JFE Chemical Corporation (Reaction initiator) PBP: Peroxide (α,α'-di(t-butylperoxy)diisopropylbenzene, perbutyl P(PBP) manufactured by NOF Corporation) (Titanate compound filler (C)) Strontium titanate particles-1: Strontium titanate particles that have not been surface-treated with a coupling agent (ST-A manufactured by Fuji Titanium Industries Co., Ltd., specific gravity 5.1 g / cm³) 3 , average particle size (D50) 1.6μm) Strontium titanate particles-2: Particles obtained by surface-treating strontium titanate particles-1 with a silane coupling agent having a methacryloyl group (methacrylsilane) (3-methacryloxypropyltrimethoxysilane, KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.). Calcium titanate particles: CT (specific gravity 4g / cm³) manufactured by Fuji Titanium Industries Co., Ltd. 3 , average particle size (D50) 2.1μm) (Silica Filler (D)) Spherical silica: SC2300-SVJ manufactured by Admatex Co., Ltd. (Specific gravity 2.3 g / cm³) 3 , average particle size (D50) 0.5μm) (Aluminum hydroxide particles) Aluminum hydroxide particles: (ALH-F manufactured by Kawai Lime Industry Co., Ltd.) (Fibrous base material) Q Glass: Quartz glass cloth (SQF1078C-04, #1078 type, manufactured by Shin-Etsu Chemical Co., Ltd., relative permittivity 3.5, dielectric loss tangent 0.0015) L2 Glass: L2 glass cloth (Asahi Kasei Corporation's L2-1078, #1078 type, relative permittivity 4.4, dielectric loss tangent 0.0018) NE Glass: NE Glass Cloth (NE1078, #1078 type, manufactured by Nitto Boseki Co., Ltd., relative permittivity 4.5, dielectric loss tangent 0.0038) E-glass: E-glass cloth (ND1078, #1078 type, manufactured by Nanya Co., Ltd., relative permittivity 6.0, dielectric loss tangent 0.0060)

[0163] [Preparation method] First, each component except for the titanate compound filler (C), silica filler (D), and aluminum hydroxide particles was added to toluene in the compositions (parts by mass) shown in Tables 1 and 2, so that the solid content concentration was 50% by mass, and the mixture was mixed. The mixture was stirred for 60 minutes. Then, the titanate compound filler (C), silica filler (D), and aluminum hydroxide particles were added to the resulting liquid in the compositions (parts by mass) shown in Tables 1 and 2, and dispersed using a bead mill. In this way, a varnish-like resin composition (varnish) was obtained.

[0164] Next, the prepreg and evaluation substrate 1 (metal-clad laminate) were obtained as follows.

[0165] The obtained varnish was impregnated into fibrous substrates (glass cloth) shown in Tables 1 and 2, and then prepregs were prepared by heating and drying at 120-150°C for 3 minutes. At that time, the content of the components constituting the resin composition in the prepreg (resin content) was adjusted so that the thickness of one prepreg sheet was 0.075 mm.

[0166] Next, evaluation substrate 1 (metal-clad laminate) was obtained as follows.

[0167] Copper foil (FV-WS manufactured by Furukawa Electric Co., Ltd., 18 μm thick) was placed on both sides of each obtained prepreg. This was used as a pressure-bearing body and heated to a temperature of 220°C at a heating rate of 3°C / min. By heating and pressurizing under the conditions of 220°C and a pressure of 3 MPa for 90 minutes, an evaluation substrate 1 (metal-clad laminate) with copper foil bonded to both sides and a thickness of approximately 0.075 mm was obtained.

[0168] Furthermore, an evaluation substrate 2 (metal-clad laminate) was also fabricated in the same manner as evaluation substrate 1 (metal-clad laminate), except that it did not use a fibrous substrate, but without a fibrous substrate.

[0169] Evaluation substrate 1 (metal-clad laminate) and evaluation substrate 2 (metal-clad laminate), which were fabricated as described above, were evaluated using the method shown below.

[0170] [Dielectric properties (relative permittivity and dielectric loss tangent)] Unclad boards, obtained by etching away the copper foil from evaluation substrate 1 (metal-clad laminate) and evaluation substrate 2 (metal-clad laminate), were used as test specimens, and the relative permittivity and dielectric loss tangent at 10 GHz were measured using the cavity resonator perturbation method. Specifically, a network analyzer (N5230A manufactured by Agilent Technologies, Inc.) was used to measure the relative permittivity and dielectric loss tangent of the evaluation substrates at 10 GHz. The relative permittivity and dielectric loss tangent obtained using evaluation substrate 1 (metal-clad laminate) are measured as the relative permittivity and dielectric loss tangent of the cured prepreg, since evaluation substrate 1 is equipped with a fibrous substrate. The relative permittivity and dielectric loss tangent obtained using evaluation substrate 2 (metal-clad laminate) are measured as the relative permittivity and dielectric loss tangent of the cured resin composition, since evaluation substrate 2 is not equipped with a fibrous substrate. The difference between the relative permittivity of the cured resin composition and the relative permittivity of the fibrous substrate was also calculated.

[0171] [Skew: delay time difference] Ten wires with a wire width of 100-300 μm, a wire length of 100 mm, and a wire spacing of 20 mm were formed by processing one of the metal foils (copper foil) on the evaluation substrate 1 (metal-clad laminate). A three-layer board was created by secondary lamination of three prepregs and metal foil (copper foil) on the surface of the substrate on which the wires were formed. The wire width of the wires was adjusted so that the characteristic impedance of the circuit after the three-layer board was fabricated was 50 Ω.

[0172] The delay time of the obtained 3-layer board at 20 GHz was measured. The difference between the maximum and minimum values ​​of the obtained delay time was calculated. This calculated difference is the delay time difference, and a large delay time difference makes differential signal skew more likely. Therefore, the delay time difference can be used as an indicator to evaluate signal quality due to skew. In other words, a large delay time difference makes signal quality degradation due to skew more likely, while a small delay time difference tends to make signal quality degradation due to skew less likely. Accordingly, as an evaluation of skew, if the calculated value (delay time difference) was 0.5 picoseconds or less, it was evaluated as "◎", if it was greater than 0.5 picoseconds but less than 1 picosecond, it was evaluated as "○", and if it was 1 picosecond or more, it was evaluated as "×".

[0173] [Coefficient of thermal expansion] First, ten sheets of the prepreg were stacked, and copper foil (FV-WS manufactured by Furukawa Electric Co., Ltd., 18 μm thick) was placed on both sides. This was used as the pressure-bearing body and heated to 220 °C at a heating rate of 3 °C / min. By heating and pressurizing at 220 °C for 90 minutes under a pressure of 3 MPa, an evaluation substrate 3 (metal-clad laminate) with copper foil bonded to both sides and a thickness of approximately 0.75 mm was obtained. An unclad plate obtained by etching off the copper foil from this evaluation substrate 3 was used as a test specimen, and the coefficient of thermal expansion in the Z-axis direction (CTE: ppm / °C) was measured by TMA (Thermo-mechanical analysis) according to JIS C 6481. A TMA apparatus (TMA6000 manufactured by SII Nanotechnology Co., Ltd.) was used for the measurement, and measurements were taken in the range of 50 to 100 °C.

[0174] [Heat resistance] Next, evaluation board 4 (10-layer board) was obtained as follows.

[0175] First, two sheets of the aforementioned prepreg were stacked together, and copper foil (FV-WS manufactured by Furukawa Electric Co., Ltd., 18 μm thick) was placed on both sides. This was used as the pressure-bearing body, and it was heated to a temperature of 210°C at a heating rate of 3°C / min. By heating and pressurizing it at 210°C for 90 minutes under a pressure of 3 MPa, a metal-clad laminate with copper foil bonded to both sides was obtained. Four of these metal-clad laminates were then prepared.

[0176] Four metal-clad laminates and the prepreg were alternately laminated so that the prepreg was on both surfaces. Two layers of prepreg were laminated between each of the metal-clad laminates. Then, the copper foil was laminated on both surfaces. This was used as a pressure-bearing body and heated to a temperature of 210°C at a heating rate of 3°C / min. By heating and pressurizing at 210°C for 90 minutes at a pressure of 3 MPa, an evaluation substrate 4 (10-layer board) was obtained. That is, the layer structure of this evaluation substrate 4 (10-layer board) is copper foil / 2 layers of the prepreg / the metal-clad laminate (copper foil / 2 layers of the prepreg / copper foil) / 2 layers of the prepreg / the metal-clad laminate / 2 layers of the prepreg / the metal-clad laminate / 2 layers of the prepreg / the metal-clad laminate / 2 layers of the prepreg / the metal-clad laminate / 2 layers of the prepreg / copper foil.

[0177] The obtained evaluation substrate 4 (10-layer board) was removed after undergoing a predetermined number of reflow processes in a reflow oven at 280°C. The presence or absence of delamination was visually observed on the evaluation substrate 4 after the reflow process. If no delamination was observed on the evaluation substrate 4 after 20 reflow processes, it was evaluated as "◎". If delamination was observed on the evaluation substrate 4 after 20 reflow processes, but not on the evaluation substrate 4 after 10 reflow processes, it was evaluated as "○". If delamination was observed on the evaluation substrate 4 after 10 reflow processes, but not on the evaluation substrate 4 after 1 reflow process, it was evaluated as "△". If delamination was observed on the evaluation substrate 4 after 1 reflow process, it was evaluated as "×".

[0178] The results for each of the above evaluations are shown in Tables 1 and 2.

[0179] [Table 1]

[0180] [Table 2]

[0181] Tables 1 and 2 show the composition of the resin composition containing the polyphenylene ether compound (A) and the curing agent (B), the fibrous substrate used when preparing the prepreg, and the evaluation results. As can be seen from Tables 1 and 2, when a metal-clad laminate is manufactured using the resin composition, if the resin composition contains the titanate compound filler (C) and the silica filler (D), and the content ratio of the titanate compound filler (C) to the silica filler (D) is 10:90 to 90:10 by mass (Examples 1 to 9), the dielectric constant is high and the dielectric loss tangent is low. Compared to cases where this is not the case (Comparative Examples 1 to 5), the heat resistance is excellent and the coefficient of thermal expansion is low. Furthermore, in Examples 1 to 9, it was found that the dielectric constant of the cured resin composition and the dielectric constant of the fibrous substrate could be approximated, and the degradation of signal quality due to skew could be sufficiently suppressed.

[0182] Specifically, in the case where the silica filler (D) was not included (Comparative Example 1), the heat resistance was inferior and the coefficient of thermal expansion was higher compared to Examples 1 to 9. Also, in the case where the silica filler (D) was included, but the content ratio (mass ratio) of the titanate compound filler (C) to the silica filler (D) was 95:5, meaning the amount of silica filler (D) was small (Comparative Example 2), similar to Comparative Example 1, the heat resistance was inferior and the coefficient of thermal expansion was high compared to Examples 1 to 9. Furthermore, in the case where the silica filler (D) was included, but the content ratio (mass ratio) of the titanate compound filler (C) to the silica filler (D) was 5:95, meaning the amount of titanate compound filler (C) was small (Comparative Example 3), the relative dielectric constant was lower compared to Examples 1 to 9. In addition, in the case where aluminum hydroxide particles were included instead of the silica filler (D) (Comparative Example 4), the dielectric loss tangent was higher compared to Examples 1 to 9. Furthermore, Comparative Example 4 exhibited inferior heat resistance and a higher coefficient of thermal expansion compared to Examples 1-9. Additionally, in the case without the titanate compound filler (C) (Comparative Example 5), the dielectric constant was lower compared to Examples 1-9. In Comparative Examples 3 and 5, it was difficult to approximate the dielectric constant of the cured resin composition with that of the fibrous substrate, and in such cases, the degradation of signal quality due to skew could not be sufficiently suppressed.

[0183] Even when a curing agent other than divinylbenzene (as in Examples 1-4) was used as the curing agent (B), such as in Example 5: TAIC and Example 6: acenaphthylene, the dielectric constant was high, the dielectric loss tangent was low, the heat resistance was excellent, and the coefficient of thermal expansion was low. From this, it was found that regardless of the type of curing agent (B), if the resin composition contains the titanate compound filler (C) and the silica filler (D), and the content ratio of the titanate compound filler (C) to the silica filler (D) is 10:90 to 90:10 by mass, the dielectric constant is high, the dielectric loss tangent is low, the heat resistance is excellent, and the coefficient of thermal expansion is low.

[0184] Even when calcium titanate particles, which are a different titanate compound filler, were used as the titanate compound filler (C) instead of strontium titanate particles as in Examples 1-4 (Example 7), or when surface-treated strontium titanate particles were used (Example 9), the relative permittivity was high, the dielectric loss tangent was low, the heat resistance was excellent, and the coefficient of thermal expansion was low. From this, it was found that regardless of the type of titanate compound filler (C), when the resin composition contains the titanate compound filler (C) and the silica filler (D), and the content ratio of the titanate compound filler (C) to the silica filler (D) is 10:90 to 90:10 by mass ratio, the relative permittivity is high, the dielectric loss tangent is low, the heat resistance is excellent, and the coefficient of thermal expansion is low.

[0185] From Example 8, it was found that the polyphenylene ether compound (A) may be not only a polyphenylene ether compound having the group represented by formula (1) in its molecule, as in Examples 1 to 4, but also a polyphenylene ether compound having the group represented by formula (2) in its molecule.

[0186] This application is based on Japanese Patent Application No. 2021-050475, filed on March 24, 2021, the contents of which are included in this application.

[0187] Although the present invention has been adequately and fully described above through embodiments, those skilled in the art should recognize that it is easy to modify and / or improve upon the embodiments described above. Therefore, unless such modifications or improvements implemented by those skilled in the art fall outside the scope of the claims, such modifications or improvements shall be considered to be included within the scope of the claims. [Industrial applicability]

[0188] The present invention provides a resin composition that yields a cured product with a high dielectric constant, a low dielectric loss tangent, and excellent heat resistance. Furthermore, the present invention provides a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that can be obtained using the resin composition.

Claims

1. A polyphenylene ether compound (A) having at least one of the group represented by the following formula (1) and the group represented by the following formula (2) in its molecule, Hardener (B), Titanate compound filler (C), Contains silica filler (D), A resin composition for wiring boards, wherein the content ratio of the titanate compound filler (C) to the silica filler (D) is 10:90 to 90:10 by mass. 【Chemistry 1】 [In formula (1), p represents 0 to 10, Ar represents an arylene group, R １ ~R ３ Each of these independently represents either a hydrogen atom or an alkyl group. 【Chemistry 2】 [In formula (2), R ４ This represents a hydrogen atom or an alkyl group.

2. The resin composition for wiring boards according to claim 1, wherein the relative dielectric constant of the titanate compound filler (C) is 50 to 800.

3. The resin composition for wiring boards according to claim 1, wherein the titanate compound filler (C) comprises at least one selected from the group consisting of titanium oxide particles, barium titanate particles, strontium titanate particles, calcium titanate particles, magnesium titanate particles, zinc titanate particles, lanthanum titanate particles, neodymium titanate particles, and aluminum titanate particles.

4. The resin composition for wiring boards according to any one of claims 1 to 3, wherein the curing agent (B) comprises at least one selected from the group consisting of allyl compounds, methacrylate compounds, acrylate compounds, acenaphthylene compounds, polybutadiene compounds, polyfunctional aromatic vinyl compounds, vinyl hydrocarbon compounds, and maleimide compounds.

5. The resin composition for wiring boards according to any one of claims 1 to 4, wherein the titanate compound filler (C) comprises at least one of strontium titanate particles and calcium titanate particles.

6. The resin composition for wiring boards according to any one of claims 1 to 5, wherein the titanate compound filler (C) is surface-treated with a silane coupling agent or a titanium coupling agent.

7. The resin composition for wiring boards according to any one of claims 1 to 6, wherein the content of the titanate compound filler (C) is 20 to 300 parts by mass with respect to 100 parts by mass of the total of the polyphenylene ether compound (A) and the curing agent (B).

8. A prepreg for a wiring board comprising a resin composition for a wiring board according to any one of claims 1 to 7 or a semi-cured product of the resin composition for a wiring board, and a fibrous substrate.

9. The relative permittivity of the cured prepreg for the wiring board at a frequency of 10 GHz is 3.5 to 7. The prepreg for a wiring board according to claim 8, wherein the difference between the relative permittivity of the cured resin composition for the wiring board at a frequency of 10 GHz and the relative permittivity of the fibrous substrate at a frequency of 10 GHz is 0 to 0.

3.

10. The prepreg for a wiring board according to claim 8 or claim 9, wherein the relative permittivity of the fibrous base material at a frequency of 10 GHz is 3.5 to 7.

11. A resin-coated film for a wiring board comprising a resin layer containing the resin composition for a wiring board described in any one of claims 1 to 7 or a semi-cured product of the resin composition for a wiring board, and a support film.

12. A resin-coated metal foil for a wiring board, comprising a resin layer containing the resin composition for a wiring board described in any one of claims 1 to 7 or a semi-cured product of the resin composition for a wiring board, and a metal foil.

13. A metal-clad laminate for a wiring board comprising an insulating layer containing a cured product of a resin composition for wiring boards according to any one of claims 1 to 7 or a cured product of a prepreg for wiring boards according to any one of claims 8 to 10, and a metal foil.

14. A wiring board comprising an insulating layer containing a cured product of a resin composition for wiring boards according to any one of claims 1 to 7 or a cured product of a prepreg for wiring boards according to any one of claims 8 to 10, and wiring.

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