Resin composition, prepreg, film with resin, metal foil with resin, metal-clad laminate, and wiring board

Abstract

To provide a resin composition capable of obtaining a cured product excellent in low dielectric characteristics, heat resistance and adhesion to a metal foil, and having a low coefficient of thermal expansion.SOLUTION: The resin composition comprises a polyphenylene ether compound having a carbon-carbon unsaturated double bond at the terminal, a maleimide compound (A) having a meta-oriented and bonded arylene structure in the molecule, and an inorganic filler.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] As the amount of information processed increases in various electronic devices, advances in packaging technologies, such as higher integration of semiconductor devices, higher density wiring, and multi-layering, are being made. Furthermore, wiring boards used in various electronic devices are required to be compatible with high frequencies, such as millimeter-wave radar boards for automotive applications. Substrate materials for constituting the insulating layers of wiring boards used in various electronic devices are required to have low relative permittivity and dielectric loss tangent in order to increase signal transmission speeds and reduce loss during signal transmission.

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

[0004] Substrate materials for forming insulating layers of wiring boards are required to not only have excellent low dielectric properties but also to have enhanced curability and to produce cured products with excellent heat resistance, etc. For this reason, it is considered that heat resistance can be improved by using a polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond in the substrate material. Examples of resin compositions containing such polyphenylene ether compounds having a terminal carbon-carbon unsaturated double bond include the resin composition described in Patent Document 1.

[0005] Patent Document 1 describes a resin composition containing a polymaleimide compound having a predetermined structure, such as one having a 4,4'-biphenyl group in the molecule, a modified polyphenylene ether terminally modified with a substituent containing a carbon-carbon unsaturated double bond, and a filler. Patent Document 1 discloses that when used as a material for printed wiring boards, etc., it is possible to provide a resin composition that can simultaneously satisfy excellent peel strength, low water absorption, desmear resistance, and heat resistance.

[0006] Metal-clad laminates and resin-coated metal foils used in manufacturing wiring boards and the like have not only an insulating layer but also a metal foil on the insulating layer. Similarly, wiring boards also have not only an insulating layer but also wiring on the insulating layer. Examples of the wiring include wiring derived from the metal foil provided on the metal-clad laminates and the like.

[0007] In recent years, small portable devices, particularly mobile communication terminals and notebook PCs, have rapidly become more multifunctional, high-performance, thin, and compact. Accordingly, wiring boards used in these products are also required to have finer conductor wiring, more multilayered conductor wiring layers, thinner designs, and higher performance in terms of mechanical properties. In particular, as wiring boards become thinner and more multilayered, warping occurs in semiconductor packages mounting semiconductor chips on the wiring board, which can lead to mounting defects and poor electrical continuity. To prevent mounting defects and poor electrical continuity in semiconductor packages mounting semiconductor chips on wiring boards, the insulating layer is required to have a low thermal expansion coefficient. Therefore, substrate materials for forming the insulating layer of wiring boards are required to produce cured products with a low thermal expansion coefficient.

[0008] Since the wiring board is required to have finer wiring that does not peel off from the insulating layer, it is more required that the adhesion between the wiring and the insulating layer is high. Therefore, the metal-clad laminate and the resin-coated metal foil are required to have high adhesion between the metal foil and the insulating layer, and the substrate material for constituting the insulating layer of the wiring board is required to give a cured product that has excellent adhesion to the metal foil.

[0009] Because wiring boards used in various electronic devices are sometimes exposed to high-temperature environments such as reflow during substrate processing, such as when mounting semiconductor chips, the substrate materials used to construct the wiring boards are required to have high heat resistance, such as a high glass transition temperature. Furthermore, in order to suppress losses due to increased resistance associated with miniaturization of wiring, the insulating layers provided on the wiring boards are increasingly required to have low dielectric constants and low dielectric dissipation factors. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] International Publication No. 2019 / 138992 Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made in view of the above circumstances, and aims to provide a resin composition that has low dielectric properties, excellent heat resistance, and adhesion to metal foil, and that can give a cured product with a low coefficient of thermal expansion. The present invention also aims to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that can be obtained using the resin composition. [Means for solving the problem]

[0012] One aspect of the present invention is a resin composition containing a polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond, a maleimide compound (A) having an arylene structure in the molecule that is oriented and bonded to the meta position, and an inorganic filler. [Effects of the Invention]

[0013] According to the present invention, there is provided a resin composition which can give a cured product having low dielectric properties, excellent heat resistance, and adhesion to metal foil, and a low coefficient of thermal expansion. Furthermore, according to the present invention, there are provided a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board, which are obtained using the resin composition. [Brief explanation of the drawings]

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

[0015] As a result of extensive investigations, the present inventors have found that the above object can be achieved by the present invention described below.

[0016] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these.

[0017] [Resin composition] The resin composition according to the present embodiment contains a polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond, a maleimide compound (A) having an arylene structure oriented at the meta position in the molecule, and an inorganic filler. By curing the resin composition having such a configuration, a cured product having low dielectric properties, excellent heat resistance, and adhesion to metal foil and a low coefficient of thermal expansion can be obtained.

[0018] First, the resin composition can have a reduced coefficient of thermal expansion by containing the inorganic filler. By curing the polyphenylene ether compound together with the maleimide compound (A), the resin composition can be cured favorably even when the inorganic filler is contained, and it is believed that a cured product with high heat resistance can be obtained while maintaining the excellent low dielectric properties of polyphenylene ether. Furthermore, by curing the polyphenylene ether compound together with the maleimide compound (A), the resulting cured product can have improved adhesion to metal foil. Furthermore, because the resin composition can be cured favorably, it is believed that the coefficient of thermal expansion of the resulting cured product can be reduced. Based on these factors, it is believed that the resin composition can produce a cured product with excellent low dielectric properties, heat resistance, and adhesion to metal foil, and a low coefficient of thermal expansion.

[0019] (Polyphenylene ether compound) The polyphenylene ether compound is not particularly limited as long as it is a polyphenylene ether compound having a carbon-carbon unsaturated double bond at its terminal. Examples of the polyphenylene ether compound include polyphenylene ether compounds having a carbon-carbon unsaturated double bond at the molecular terminal, and more specifically, polyphenylene ether compounds having a substituent having a carbon-carbon unsaturated double bond at the molecular terminal, such as modified polyphenylene ether compounds whose terminals are modified with a substituent having a carbon-carbon unsaturated double bond.

[0020] Examples of the substituent having a carbon-carbon unsaturated double bond include a group represented by the following formula (3) and a group represented by the following formula (4): That is, examples of the polyphenylene ether compound include a polyphenylene ether compound having at least one selected from the group represented by the following formula (3) and the group represented by the following formula (4) at a molecular end.

[0021] [ka] In formula (3), 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 a hydrogen atom or an alkyl group. Ar2 represents an arylene group. p represents 0 to 10. In addition, when p is 0 in formula (3), it means that Ar2 is directly bonded to the terminal of the polyphenylene ether.

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

[0023] The alkyl group is not particularly limited, and is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0024] [ka] In formula (4), R4 represents a hydrogen atom or an alkyl group. The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0025] Examples of the group represented by the formula (3) include a vinylbenzyl group (ethenylbenzyl group) represented by the following formula (5): Furthermore, examples of the group represented by the formula (4) include an acryloyl group and a methacryloyl group.

[0026] [ka]

[0027] More specifically, examples of the substituent include vinylbenzyl groups (ethenylbenzyl groups) such as o-ethenylbenzyl groups, m-ethenylbenzyl groups, and p-ethenylbenzyl groups, vinylphenyl groups, acryloyl groups, and methacryloyl groups. The polyphenylene ether compound may have one type of substituent, or two or more types. The polyphenylene ether compound may have, for example, any one of o-ethenylbenzyl groups, m-ethenylbenzyl groups, and p-ethenylbenzyl groups, or may have two or three types of these.

[0028] The polyphenylene ether compound has a polyphenylene ether chain in the molecule, and preferably has, for example, a repeating unit represented by the following formula (6) in the molecule.

[0029] [ka] In formula (6), t represents 1 to 50. R5 to R8 are each independent. That is, R5 to R8 may be the same group or different groups. 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. Of these, a hydrogen atom and an alkyl group are preferred.

[0030] Specific examples of the functional groups listed for R5 to R8 include the following.

[0031] The alkyl group is not particularly limited, but is preferably an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0032] The alkenyl group is not particularly limited, but is preferably an alkenyl group having 2 to 18 carbon atoms, and more preferably an alkenyl group having 2 to 10 carbon atoms. Specific examples include a vinyl group, an allyl group, and a 3-butenyl group.

[0033] The alkynyl group is not particularly limited, but is preferably an alkynyl group having 2 to 18 carbon atoms, and more preferably an alkynyl group having 2 to 10 carbon atoms. Specific examples include an ethynyl group and a prop-2-yn-1-yl group (propargyl group).

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

[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. Specific examples include an acryloyl group, a methacryloyl group, and a crotonoyl group.

[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. Specific examples include a propioloyl group.

[0037] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polyphenylene ether compound are not particularly limited, and are preferably 500 to 5,000, more preferably 800 to 4,000, and even more preferably 1,000 to 3,000. The weight-average molecular weight and number-average molecular weight may be measured by a common molecular weight measurement method, specifically, values ​​measured using gel permeation chromatography (GPC) may be used. Furthermore, when the polyphenylene ether compound has a repeating unit represented by the formula (6) in the molecule, t is preferably a value such that the weight-average molecular weight and number-average molecular weight of the polyphenylene ether compound fall within the above ranges. 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 ranges, the compound has the excellent low dielectric properties of polyphenylene ether, and the cured product not only has excellent heat resistance but also has excellent moldability. This is believed to be due to the following reasons. When the weight-average molecular weight and number-average molecular weight are within the above ranges, ordinary polyphenylene ethers have a relatively low molecular weight, which tends to reduce heat resistance. In this regard, the polyphenylene ether compound according to the present embodiment has one or more unsaturated double bonds at its terminals, and therefore, as the curing reaction progresses, it is believed that 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 ranges, it is believed that the compound has a relatively low molecular weight and therefore has excellent moldability. Therefore, it is believed that such polyphenylene ether compounds not only have excellent heat resistance but also excellent moldability can be obtained as a cured product.

[0039] The average number of the substituents (number of terminal functional groups) at the molecular terminals per molecule of the polyphenylene ether compound is not particularly limited. Specifically, it is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.5 to 3. If the number of terminal functional groups is too small, it tends to be difficult to obtain a cured product with sufficient heat resistance. On the other hand, if the number of terminal functional groups is too large, the reactivity becomes too high, which may cause problems such as reduced shelf life and reduced fluidity of the resin composition. That is, when such a polyphenylene ether compound is used, insufficient fluidity may cause molding defects such as the generation of voids during multilayer molding, which may lead to moldability problems such as difficulty in obtaining a highly reliable printed wiring board.

[0040] The number of terminal functional groups in a polyphenylene ether compound may be, for example, a numerical value representing the average number of the substituents per molecule of all polyphenylene ether compounds present in 1 mole of the polyphenylene ether compound. The number of terminal functional groups can be measured, for example, by measuring the number of hydroxyl groups remaining in the resulting polyphenylene ether compound and calculating the difference from the number of hydroxyl groups in the polyphenylene ether before the substituents are introduced (before modification). This difference from the number of hydroxyl groups in the polyphenylene ether before modification is the number of terminal functional groups. The number of hydroxyl groups remaining in the 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 resulting mixed solution.

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

[0042] The intrinsic viscosity here is the intrinsic viscosity measured in methylene chloride at 25°C, and more specifically, for example, is the value measured using a viscometer for a 0.18 g / 45 ml methylene chloride solution (liquid temperature: 25°C). Examples of such a viscometer include the AVS500 Visco System manufactured by Schott.

[0043] Examples of the polyphenylene ether compound include a polyphenylene ether compound represented by the following formula (7) and a polyphenylene ether compound represented by the following formula (8). As the polyphenylene ether compound, these polyphenylene ether compounds may be used alone, or these two types of polyphenylene ether compounds may be used in combination.

[0044] [ka]

[0045] [ka]

[0046] In formula (7) and formula (8), R9 to R 16 and R 17 ~R 24 are independent of each other. That is, R9 to R 16 and R17 ~R 24 may be the same group or different groups. 16 and R 17 ~R 24 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. X1 and X2 are each independent. That is, X1 and X2 may be the same group or different groups. X1 and X2 represent a substituent having a carbon-carbon unsaturated double bond. A and B represent repeating units represented by the following formula (9) and formula (10), respectively. In addition, in formula (8), Y represents a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms.

[0047] [ka]

[0048] [ka]

[0049] In the formulas (9) and (10), m and n each represent an integer of 0 to 20. 25 ~R 28 and R 29 ~R 32 are independent of each other. That is, R 25 ~R 28 and R 29 ~R 32 may be the same group or different groups. 25 ~R 28 and R 29 ~R 32 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.

[0050] The polyphenylene ether compound represented by the formula (7) and the polyphenylene ether compound represented by the formula (8) are not particularly limited as long as they satisfy the above-mentioned constitution. Specifically, in the formulas (7) and (8), R9 to R 16 and R 17 ~R 24 As mentioned above, R9 to R 16 and R 17 ~R 24 may be the same group or different groups. 16 and R 17 ~R 24 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0051] In the formulas (9) and (10), m and n each preferably represent a value of 0 to 20, as described above. Furthermore, it is preferable that m and n represent a numerical value such that the sum of m and n is 1 to 30. Therefore, it is more preferable that m represents a numerical value of 0 to 20, n represents a numerical value of 0 to 20, and the sum of m and n represents a numerical value of 1 to 30. Furthermore, R 25 ~R 28 and R 29 ~R 32 are independent of each other. That is, R 25 ~R 28 and R 29 ~R 32 may be the same group or different groups. 25 ~R 28 and R 29 ~R 32 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0052] R9~R 32 are the same as R5 to R8 in the above formula (6).

[0053] In the formula (8), Y is, as described above, a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms. Examples of Y include a group represented by the following formula (11).

[0054] [ka] In the formula (11), R 33 and R 34 are each independently a hydrogen atom or an alkyl group. Examples of the alkyl group include a methyl group. Examples of the group represented by formula (11) include a methylene group, a methylmethylene group, and a dimethylmethylene group, and among these, a dimethylmethylene group is preferred.

[0055] In the formula (7) and the formula (8), X1 and X2 each independently represent a substituent having a carbon-carbon double bond. In the polyphenylene ether compound represented by the formula (7) and the polyphenylene ether compound represented by the formula (8), X1 and X2 may be the same group or different groups.

[0056] More specific examples of the polyphenylene ether compound represented by the formula (7) include polyphenylene ether compounds represented by the following formula (12).

[0057] [ka]

[0058] More specific examples of the polyphenylene ether compound represented by the formula (8) include a polyphenylene ether compound represented by the following formula (13) and a polyphenylene ether compound represented by the following formula (14).

[0059] [ka]

[0060] [ka]

[0061] In the above formulas (12) to (14), m and n are the same as m and n in the above formulas (9) and (10). In addition, in the above formulas (12) and (13), R1 to R3, p, and Ar2 are the same as R1 to R3, p, and Ar2 in the above formula (3). In addition, in the above formulas (13) and (14), Y is the same as Y in the above formula (8). In addition, in the above formula (14), R4 is the same as R4 in the above formula (4).

[0062] The method for synthesizing the polyphenylene ether compound used in the present embodiment is not particularly limited as long as it can synthesize a polyphenylene ether compound having a carbon-carbon unsaturated double bond in the molecule. Specific examples of this method include a method of reacting polyphenylene ether with a compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded.

[0063] Examples of the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded include compounds in which a halogen atom is bonded to a substituent represented by any of the formulas (3) to (5). Specific examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom, with a chlorine atom being preferred. More specific examples of the compound in which a halogen atom is bonded to a substituent having a carbon-carbon unsaturated double bond include o-chloromethylstyrene, p-chloromethylstyrene, and m-chloromethylstyrene. The compound in which a halogen atom is bonded to a substituent having a carbon-carbon unsaturated double bond 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 more.

[0064] The polyphenylene ether used as the raw material is not particularly limited as long as it can ultimately synthesize a predetermined polyphenylene ether compound. Specific examples include polyphenylene ethers composed of 2,6-dimethylphenol and at least one of a bifunctional phenol and a trifunctional phenol, and those containing polyphenylene ether as the main component, such as poly(2,6-dimethyl-1,4-phenylene oxide). Furthermore, a bifunctional phenol is a phenolic compound having two phenolic hydroxyl groups per molecule, such as tetramethylbisphenol A. Furthermore, a trifunctional phenol is a phenolic compound having three phenolic hydroxyl groups per molecule.

[0065] The polyphenylene ether compound can be synthesized by the method described above. Specifically, the polyphenylene ether 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 reacts with the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, thereby obtaining the polyphenylene ether compound used in this embodiment.

[0066] The reaction is preferably carried out in the presence of an alkali metal hydroxide. It is believed that this allows the reaction to proceed smoothly. This is believed to be because the alkali metal hydroxide functions as a dehydrohalogenating agent, specifically, a dehydrochlorinating agent. That is, it is believed that the alkali metal hydroxide eliminates hydrogen halide from the phenol group of the polyphenylene ether and the compound in which the substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and as a result, the substituent having a carbon-carbon unsaturated double bond is bonded to the oxygen atom of the phenol group in place of the hydrogen atom of the phenol group of the polyphenylene ether.

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

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

[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 a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and does not inhibit the reaction between the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded. Specific examples include toluene.

[0070] The above reaction is preferably carried out in the presence of not only an alkali metal hydroxide but also a phase transfer catalyst. That is, the above reaction is preferably carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst. Doing so is believed to allow the reaction to proceed more smoothly. This is believed to be due to the following: A phase transfer catalyst has the function of incorporating an alkali metal hydroxide, is soluble in both a polar solvent phase such as water and a nonpolar solvent phase such as an organic solvent, and is capable of transferring between these phases. Specifically, when an aqueous solution of sodium hydroxide is used as the alkali metal hydroxide and an organic solvent such as toluene, which is incompatible with water, is used as the solvent, even if the aqueous solution of sodium hydroxide is added dropwise to the solvent being used for the reaction, the solvent and the aqueous solution of sodium hydroxide separate, and it is believed that the sodium hydroxide is unlikely to migrate to the solvent. In this case, it is believed that the aqueous solution of sodium hydroxide added as the alkali metal hydroxide is unlikely to contribute to promoting the reaction. On the other hand, when the reaction is carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst, the alkali metal hydroxide is transferred to the solvent while being incorporated into the phase transfer catalyst, and the aqueous sodium hydroxide solution is thought to contribute more to promoting the reaction. Therefore, when the reaction is carried out in the presence of an alkali metal hydroxide and a phase transfer catalyst, the reaction is thought to proceed more smoothly.

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

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

[0073] (Maleimide compound (A)) The maleimide compound (A) is not particularly limited as long as it has an arylene structure in the molecule that is oriented and bonded at the meta position. Examples of the arylene structure that is oriented and bonded at the meta position include an arylene structure in which a structure containing a maleimide group is bonded at the meta position (an arylene structure in which a structure containing a maleimide group is substituted at the meta position). The arylene structure that is oriented and bonded at the meta position is an arylene group that is oriented and bonded at the meta position, such as a group represented by the following formula (15). Examples of the arylene structure that is oriented and bonded at the meta position include m-arylene groups such as m-phenylene and m-naphthylene groups, and more specifically, a group represented by the following formula (15).

[0074] [ka]

[0075] Examples of the maleimide compound (A) include a maleimide compound (A1) represented by the following formula (1), and more specifically, a maleimide compound (A2) represented by the following formula (2).

[0076] [ka] In formula (1), Ar1 represents an arylene group bonded in a meta-position. A , R B , R C , and R D are independent of each other. That is, R A , R B , R C , and R D may be the same group or different groups. A , R B , R C , and R D represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and is preferably a hydrogen atom. E and R Fare independent of each other. That is, R E and R F may be the same group or different groups. E and R F represents an aliphatic hydrocarbon group. s represents 1 to 5.

[0077] The arylene group is not particularly limited as long as it is an arylene group oriented and bonded at the meta position, and examples thereof include m-arylene groups such as m-phenylene and m-naphthylene groups, and more specifically, examples thereof include groups represented by the formula (15).

[0078] Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and a neopentyl group.

[0079] The aliphatic hydrocarbon group is a divalent group and may be acyclic or cyclic. Examples of the aliphatic hydrocarbon group include alkylene groups, more specifically methylene groups, methylmethylene groups, and dimethylmethylene groups. Among these, the dimethylmethylene group is preferred.

[0080] In the maleimide compound (A1) represented by the formula (1), the repeating number s is preferably 1 to 5. This s is the average value of the repeating number (degree of polymerization).

[0081] [ka] In formula (2), s represents 1 to 5. This s is the same as s in formula (1) and is the average value of the number of repetitions (degree of polymerization).

[0082] The maleimide compound (A1) represented by the formula (1) and the maleimide compound (A2) represented by the formula (2) may contain a monofunctional compound where s is 0, or a polyfunctional compound such as a heptafunctional compound or an octafunctional compound where s is 6 or more, as long as s, which is the average value of the repeating number (degree of polymerization), is 1 to 5.

[0083] As the maleimide compound (A), a commercially available product may be used, for example, the solid content in MIR-5000-60T manufactured by Nippon Kayaku Co., Ltd.

[0084] As the maleimide compound (A), the maleimide compounds exemplified above may be used alone or in combination of two or more. For example, as the maleimide compound (A), the maleimide compound (A1) represented by formula (1) may be used alone, or two or more types of the maleimide compound (A1) represented by formula (1) may be used in combination. When two or more types of the maleimide compound (A1) represented by formula (1) are used in combination, for example, a maleimide compound (A1) represented by formula (1) other than the maleimide compound (A2) represented by formula (2) may be used in combination with the maleimide compound (A2) represented by formula (2).

[0085] (Inorganic filler) The inorganic filler is not particularly limited as long as it can be used as an inorganic filler contained in a resin composition. Examples of the inorganic filler include metal oxides such as silica, alumina, titanium oxide, magnesium oxide, and mica, metal hydroxides such as magnesium hydroxide and aluminum hydroxide, talc, aluminum borate, barium sulfate, aluminum nitride, boron nitride, barium titanate, magnesium carbonate such as anhydrous magnesium carbonate, and calcium carbonate. Among these, silica, metal hydroxides such as magnesium hydroxide and aluminum hydroxide, aluminum oxide, boron nitride, and barium titanate are preferred, and silica is more preferred. The silica is not particularly limited, and examples include crushed silica, spherical silica, and silica particles.

[0086] The inorganic filler may be a surface-treated or untreated inorganic filler. Examples of the surface treatment include treatment with a silane coupling agent.

[0087] Examples of the silane coupling agent include silane coupling agents having at least one functional group selected from the group consisting of a vinyl group, a styryl group, a methacryloyl group, an acryloyl group, a phenylamino group, an isocyanurate group, a ureido group, a mercapto group, an isocyanate group, an epoxy group, and an acid anhydride group. That is, the silane coupling agent has at least one reactive functional group selected from the group consisting of a vinyl group, a styryl group, a methacryloyl group, an acryloyl group, a phenylamino group, an isocyanurate group, a ureido group, a mercapto group, an isocyanate group, an epoxy group, and an acid anhydride group, and further includes compounds having a hydrolyzable group such as a methoxy group or an ethoxy group.

[0088] Examples of the silane coupling agent include those having a vinyl group, such as vinyltriethoxysilane and vinyltrimethoxysilane. Examples of the silane coupling agent include those having a styryl group, such as p-styryltrimethoxysilane and p-styryltriethoxysilane. Examples of the silane coupling agent include those having a methacryloyl group, such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropylethyldiethoxysilane. Examples of the silane coupling agent include those having an acryloyl group, such as 3-acryloxypropyltrimethoxysilane and 3-acryloxypropyltriethoxysilane. Examples of the silane coupling agent include those having a phenylamino group, such as N-phenyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltriethoxysilane.

[0089] The average particle size of the inorganic filler is not particularly limited, and is preferably 0.05 to 10 μm, and more preferably 0.5 to 8 μm. Here, the average particle size refers to the volume average particle size. The volume average particle size can be measured, for example, by laser diffraction or the like.

[0090] (hardening agent) The resin composition according to the present embodiment may contain, as necessary, a curing agent that reacts with at least one of the polyphenylene ether compound and the maleimide compound (A), as long as the effects of the present invention are not impaired. Here, the curing agent refers to a compound that reacts with at least one of the polyphenylene ether compound and the maleimide compound (A) to contribute to curing of the resin composition. Examples of the curing agent include a maleimide compound (B) different from the maleimide compound (A), an epoxy compound, a methacrylate compound, an acrylate compound, a vinyl compound, a cyanate ester compound, an active ester compound, and an allyl compound.

[0091] The maleimide compound (B) is a maleimide compound having a maleimide group in the molecule and not having an arylene structure bonded in a meta-oriented manner in the molecule. Examples of the maleimide compound (B) include a maleimide compound having one or more maleimide groups in the molecule and a modified maleimide compound. The maleimide compound (B) is not particularly limited as long as it is a maleimide compound having one or more maleimide groups in the molecule and not having an arylene structure bonded in a meta-oriented manner in the molecule. Specific examples of the maleimide compound (B) include phenylmaleimide compounds such as 4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, and biphenylaralkyl polymaleimide compounds, as well as N-alkyl bismaleimide compounds having an aliphatic skeleton. Examples of the modified maleimide compounds include modified maleimide compounds in which a portion of the molecule is modified with an amine compound, and modified maleimide compounds in which a portion of the molecule is modified with a silicone compound. As the maleimide compound (B), commercially available products may be used. For example, the solid content of MIR-3000-70MT manufactured by Nippon Kayaku Co., Ltd., BMI-4000 and BMI-5100 manufactured by Daiwa Kasei Kogyo Co., Ltd., and BMI-689, BMI-1500, BMI-3000J, and BMI-5000 manufactured by Designer Molecules Inc. may be used.

[0092] The epoxy compound is a compound having an epoxy group in the molecule, and specific examples thereof include bisphenol-type epoxy compounds such as bisphenol A-type epoxy compounds, phenol novolac-type epoxy compounds, cresol novolac-type epoxy compounds, dicyclopentadiene-type epoxy compounds, bisphenol A novolac-type epoxy compounds, biphenyl aralkyl-type epoxy compounds, and naphthalene ring-containing epoxy compounds. The epoxy compound also includes epoxy resins, which are polymers of the above epoxy compounds.

[0093] The methacrylate compound is a compound having a methacryloyl group in the molecule, and examples thereof include monofunctional methacrylate compounds having one methacryloyl group in the molecule and polyfunctional methacrylate compounds having two or more methacryloyl groups in the molecule. Examples of the monofunctional methacrylate compound include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Examples of the polyfunctional methacrylate compound include dimethacrylate compounds such as tricyclodecane dimethanol dimethacrylate (DCP).

[0094] The acrylate compound is a compound having an acryloyl group in the molecule, and examples thereof include monofunctional acrylate compounds having one acryloyl group in the molecule and polyfunctional acrylate compounds having two or more acryloyl groups in the molecule. Examples of the monofunctional acrylate compound include methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. Examples of the polyfunctional acrylate compound include diacrylate compounds such as tricyclodecane dimethanol diacrylate.

[0095] The vinyl compound is a compound having a vinyl group in the molecule, and examples thereof include a monofunctional vinyl compound (monovinyl compound) having one vinyl group in the molecule and a polyfunctional vinyl compound having two or more vinyl groups in the molecule. Examples of the polyfunctional vinyl compound include divinylbenzene, curable polybutadiene having a carbon-carbon unsaturated double bond in the molecule, and curable butadiene-styrene copolymer having a carbon-carbon unsaturated double bond in the molecule.

[0096] The cyanate ester compound is a compound having a cyanate group in the molecule, and examples thereof include 2,2-bis(4-cyanatephenyl)propane, bis(3,5-dimethyl-4-cyanatephenyl)methane, and 2,2-bis(4-cyanatephenyl)ethane.

[0097] The active ester compound is a compound having an ester group with high reactivity in the molecule, and examples thereof include benzenecarboxylic acid active ester, benzenedicarboxylic acid active ester, benzenetricarboxylic acid active ester, benzenetetracarboxylic acid active ester, naphthalenecarboxylic acid active ester, naphthalenedicarboxylic acid active ester, naphthalenetricarboxylic acid active ester, naphthalenetetracarboxylic acid active ester, fluorenecarboxylic acid active ester, fluorenedicarboxylic acid active ester, fluorenetricarboxylic acid active ester, and fluorenetetracarboxylic acid active ester.

[0098] The allyl compound is a compound having an allyl group in the molecule, and examples thereof include triallyl isocyanurate compounds such as triallyl isocyanurate (TAIC), diallyl bisphenol compounds, and diallyl phthalate (DAP).

[0099] The curing agent may be used alone or in combination of two or more kinds.

[0100] The weight-average molecular weight of the curing agent is not particularly limited and is preferably 100 to 5000, more preferably 100 to 4000, and even more preferably 100 to 3000. If the weight-average molecular weight of the curing agent is too low, the curing agent may be more likely to volatilize from the resin composition's blending components. If the weight-average molecular weight of the curing agent is too high, the viscosity of the resin composition varnish or the melt viscosity when the resin composition is brought to a B-stage may become too high, resulting in poor moldability and a poor appearance after molding. Therefore, when the weight-average molecular weight of the curing agent is within this range, a resin composition with excellent heat resistance and moldability of the cured product can be obtained. This is thought to be because the resin composition can be cured appropriately. The weight-average molecular weight may be measured using a general molecular weight measurement method, specifically, a value measured using gel permeation chromatography (GPC), etc.

[0101] The curing agent has an average number of functional groups per molecule that contribute to the reaction during curing of the resin composition (number of functional groups), which varies depending on the weight-average molecular weight of the curing agent, but is preferably, for example, 1 to 20, and more preferably 2 to 18. If the number of functional groups is too small, it tends to be difficult to obtain sufficient heat resistance of the cured product. On the other hand, if the number of functional groups is too large, the reactivity becomes too high, which may cause problems such as reduced storage stability and reduced fluidity of the resin composition.

[0102] (thermoplastic styrene polymer) The resin composition according to this embodiment may contain a thermoplastic styrene-based polymer as needed, as long as the effects of the present invention are not impaired.

[0103] The thermoplastic styrene-based polymer may be, for example, a polymer obtained by polymerizing a monomer containing a styrene-based monomer, and may be a styrene-based copolymer. Furthermore, the styrene-based copolymer may be, for example, a copolymer obtained by copolymerizing one or more of the styrene-based monomers with one or more other monomers copolymerizable with the styrene-based monomer. The thermoplastic styrene-based polymer may be a hydrogenated styrene-based copolymer obtained by hydrogenating the styrene-based copolymer.

[0104] The styrene-based monomer is not particularly limited, but examples thereof include styrene, styrene derivatives, styrene in which some of the hydrogen atoms on the benzene ring have been substituted with alkyl groups, styrene in which some of the hydrogen atoms on the vinyl group have been substituted with alkyl groups, vinyltoluene, α-methylstyrene, butylstyrene, dimethylstyrene, isopropenyltoluene, etc. These styrene-based monomers may be used alone or in combination of two or more.

[0105] The copolymerizable other monomer is not particularly limited, and examples thereof include olefins such as α-pinene, β-pinene, and dipentene, non-conjugated dienes such as 1,4-hexadiene and 3-methyl-1,4-hexadiene, conjugated dienes such as 1,3-butadiene and 2-methyl-1,3-butadiene (isoprene), etc. The copolymerizable other monomers may be used alone or in combination of two or more.

[0106] Examples of the styrene copolymer include methylstyrene (ethylene / butylene) methylstyrene copolymer, methylstyrene (ethylene-ethylene / propylene) methylstyrene copolymer, styrene-isoprene copolymer, styrene-isoprene styrene copolymer, styrene (ethylene / butylene) styrene copolymer, styrene (ethylene-ethylene / propylene) styrene copolymer, styrene-butadiene styrene copolymer, styrene (butadiene / butylene) styrene copolymer, and styrene-isobutylene styrene copolymer.

[0107] Examples of the hydrogenated styrene copolymer include hydrogenated products of the styrene copolymers. More specific examples of the hydrogenated styrene copolymer include hydrogenated methylstyrene (ethylene / butylene) methylstyrene copolymer, hydrogenated methylstyrene (ethylene-ethylene / propylene) methylstyrene copolymer, hydrogenated styrene-isoprene copolymer, hydrogenated styrene-isoprene styrene copolymer, hydrogenated styrene (ethylene / butylene) styrene copolymer, and hydrogenated styrene (ethylene-ethylene / propylene) styrene copolymer.

[0108] The thermoplastic styrene polymers may be used alone or in combination of two or more kinds.

[0109] The thermoplastic styrene polymer preferably has a weight-average molecular weight of 1,000 to 300,000, more preferably 1,200 to 200,000. If the molecular weight is too low, the glass transition temperature of the cured product of the resin composition tends to decrease, and the heat resistance tends to decrease. If the molecular weight is too high, the viscosity of the resin composition when made into a varnish or when heat-molded tends to become too high. The weight-average molecular weight may be measured by a general molecular weight measurement method, and specific examples include values ​​measured using gel permeation chromatography (GPC).

[0110] (Content) The content of the maleimide compound (A) is preferably 1 to 90 parts by mass, more preferably 5 to 80 parts by mass, and even more preferably 20 to 50 parts by mass, relative to 100 parts by mass of the total mass of the polyphenylene ether compound and the maleimide compound (A). That is, the content of the polyphenylene ether compound is preferably 10 to 99 parts by mass, more preferably 20 to 95 parts by mass, and even more preferably 50 to 80 parts by mass, relative to 100 parts by mass of the total mass of the polyphenylene ether compound and the maleimide compound (A). If the content of the maleimide compound (A) is too low, the effects of adding the maleimide compound (A) are less likely to be achieved. For example, the thermal expansion coefficient may not be sufficiently reduced, and excellent heat resistance may be difficult to maintain. Furthermore, if the content of the maleimide compound (A) is too low or too high, adhesion to metal foil tends to be reduced. For these reasons, when the contents of the maleimide compound (A) and the polyphenylene ether compound are each within the above range, a resin composition can be obtained that has excellent low dielectric properties and heat resistance, a low thermal expansion coefficient, and a cured product with excellent adhesion to metal foil.

[0111] The content of the inorganic filler is preferably 10 to 250 parts by mass, and more preferably 40 to 200 parts by mass, relative to 100 parts by mass of the total mass of the polyphenylene ether compound and the maleimide compound (A).

[0112] As described above, the resin composition may contain a curing agent and a thermoplastic styrene-based polymer. When the resin composition contains the curing agent, the content of the curing agent is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, per 100 parts by mass of the total of the polyphenylene ether compound and the maleimide compound (A). When the resin composition contains the thermoplastic styrene-based polymer, the content of the thermoplastic styrene-based polymer is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, per 100 parts by mass of the total of the polyphenylene ether compound and the maleimide compound (A).

[0113] (Other ingredients) The resin composition according to the present embodiment may contain, as necessary, components other than the polyphenylene ether compound, the maleimide compound (A), and the inorganic filler (other components) within a range that does not impair the effects of the present invention. The other components contained in the resin composition according to the present embodiment may include not only the curing agent and thermoplastic styrene-based polymer as described above, but also additives such as a reaction initiator, a reaction accelerator, a catalyst, a polymerization retarder, a polymerization inhibitor, a dispersant, a leveling agent, a silane coupling agent, an antifoaming agent, an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a dye or pigment, and a lubricant.

[0114] As described above, the resin composition according to this embodiment may contain a reaction initiator. The reaction initiator is not particularly limited as long as it can accelerate the curing reaction of the resin composition, and examples thereof include peroxides and organic azo compounds. Examples of peroxides include α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, and benzoyl peroxide. Examples of organic azo compounds include azobisisobutyronitrile. If necessary, a metal carboxylate or the like can be used in combination. This further accelerates the curing reaction. Among these, α,α'-bis(t-butylperoxy-m-isopropyl)benzene is preferred. α,α'-bis(t-butylperoxy-m-isopropyl)benzene has a relatively high reaction initiation temperature, which can suppress acceleration of the curing reaction when curing is not required, such as during prepreg drying, thereby suppressing deterioration in the shelf life of the resin composition. Furthermore, α,α'-bis(t-butylperoxy-m-isopropyl)benzene has low volatility and does not volatilize during drying or storage of the prepreg, resulting in good stability. The reaction initiators may be used alone or in combination of two or more.

[0115] As described above, the resin composition according to this embodiment may contain a silane coupling agent. The silane coupling agent may be contained in the resin composition, or may be contained as a silane coupling agent that has been surface-treated in advance on an inorganic filler contained in the resin composition. Among these, the silane coupling agent is preferably contained as a silane coupling agent that has been surface-treated in advance on an inorganic filler, and it is more preferable to contain the silane coupling agent in advance on an inorganic filler in this way, and further to contain the silane coupling agent in the resin composition. In addition, in the case of a prepreg, the prepreg may contain the silane coupling agent that has been surface-treated in advance on a fibrous substrate. Examples of the silane coupling agent include the same silane coupling agents as those used when surface-treating the inorganic filler described above.

[0116] As described above, the resin composition according to this embodiment may contain a flame retardant. The inclusion of a flame retardant can enhance the flame retardancy of the cured resin composition. The flame retardant is not particularly limited. Specifically, in fields where halogen-based flame retardants such as bromine-based flame retardants are used, for example, ethylene dipentabromobenzene, ethylene bistetrabromoimide, decabromodiphenyl oxide, and tetradecabromodiphenoxybenzene, which have melting points of 300°C or higher, are preferred. The use of a halogen-based flame retardant is believed to suppress halogen elimination at high temperatures and prevent a decrease in heat resistance. Furthermore, in fields where halogen-free materials are required, phosphorus-containing flame retardants (phosphorus-based flame retardants) are sometimes used. Examples of the phosphorus-based flame retardant include, but are not limited to, phosphate ester-based flame retardants, phosphazene-based flame retardants, bisdiphenylphosphine oxide-based flame retardants, and phosphinate-based flame retardants. Specific examples of phosphate ester-based flame retardants include condensed phosphate esters of dixylenyl phosphate. A specific example of a phosphazene-based flame retardant is phenoxyphosphazene. A specific example of a bisdiphenylphosphine oxide-based flame retardant is xylylenebisdiphenylphosphine oxide. A specific example of a phosphinate-based flame retardant is, for example, a metal phosphinate salt of an aluminum dialkylphosphinate. As the flame retardant, each of the exemplified flame retardants may be used alone or in combination of two or more.

[0117] (Manufacturing method) The method for producing the resin composition is not particularly limited, and examples thereof include a method in which the polyphenylene ether compound, the maleimide compound (A), and the inorganic filler are mixed to a predetermined content, etc. In addition, in the case of obtaining a varnish-like composition containing an organic solvent, the method described below can be used.

[0118] Furthermore, by using the resin composition according to this embodiment, a prepreg, a metal-clad laminate, a wiring board, a resin-coated metal foil, and a resin-coated film can be obtained as follows.

[0119] [Prepreg] FIG. 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to an embodiment of the present invention.

[0120] 1, the prepreg 1 according to this embodiment comprises the resin composition or a semi-cured product of the resin composition 2, and a fibrous base material 3. This prepreg 1 comprises the resin composition or a semi-cured product of the resin composition 2, and the fibrous base material 3 present in the resin composition or the semi-cured product of the resin composition 2.

[0121] In this embodiment, the semi-cured product refers to a resin composition that has been partially cured to the extent that it can be further cured. That is, the semi-cured product refers to a resin composition that has been semi-cured (B-staged). For example, when a resin composition is heated, the viscosity initially gradually decreases, and then curing begins, and the viscosity gradually increases. In such a case, the semi-cured state can be exemplified by the state between when the viscosity starts to increase and when the composition is completely cured.

[0122] The prepreg obtained using the resin composition according to this embodiment may comprise a semi-cured product of the resin composition as described above, or may comprise the uncured resin composition itself. That is, it may be a prepreg comprising a semi-cured product of the resin composition (the resin composition in B stage) and a fibrous base material, or a prepreg comprising the resin composition before curing (the resin composition in A stage) and a fibrous base material. Furthermore, the resin composition or the semi-cured product of the resin composition may be obtained by drying or heat-drying the resin composition.

[0123] When producing the prepreg, the resin composition 2 is often prepared in a varnish form and used to impregnate the fibrous base material 3, which is the base material for forming the prepreg. That is, the resin composition 2 is usually often a resin varnish prepared in a varnish form. Such a varnish-like resin composition (resin varnish) is prepared, for example, as follows.

[0124] First, each component that is soluble in an organic solvent is added to the organic solvent and dissolved. Heating may be performed as necessary. Then, components that are insoluble in the organic solvent are added as needed, and the mixture is dispersed using a ball mill, bead mill, planetary mixer, roll mill, or the like until a predetermined dispersion state is achieved, thereby preparing a varnish-like resin composition. The organic solvent used here is not particularly limited as long as it dissolves the polyphenylene ether compound, the curing agent, and the like and does not inhibit the curing reaction. Specific examples include toluene and methyl ethyl ketone (MEK).

[0125] 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. Glass cloth can be used to obtain a laminate with excellent mechanical strength, and flattened glass cloth is particularly preferred. A specific example of the flattening process is a method in which glass cloth is continuously pressed with a press roll at an appropriate pressure to compress the yarns flat. The thickness of commonly used fibrous substrates is, for example, 0.01 mm or more and 0.3 mm or less. The glass fibers constituting the glass cloth are not particularly limited, and examples include Q glass, NE glass, E glass, S glass, T glass, L glass, and L2 glass. The surface of the fibrous substrate may be treated with a silane coupling agent. The silane coupling agent is not particularly limited, but examples thereof include silane coupling agents having at least one group selected from the group consisting of a vinyl group, an acryloyl group, a methacryloyl group, a styryl group, an amino group, and an epoxy group in the molecule.

[0126] The method for producing the prepreg is not particularly limited as long as it can produce the prepreg. Specifically, when producing the prepreg, the resin composition according to the present embodiment is often prepared in the form of a varnish, as described above, and used as a resin varnish.

[0127] Specific examples of methods for producing the prepreg 1 include a method in which the resin composition 2, for example, a resin composition 2 prepared in a varnish form, is impregnated into a fibrous substrate 3, followed by drying. The resin composition 2 is impregnated into the fibrous substrate 3 by immersion, coating, or the like. Impregnation can be repeated multiple times as necessary. In this case, by repeating the impregnation using multiple resin compositions with different compositions and concentrations, it is possible to adjust the final composition and impregnation amount to the desired one.

[0128] The fibrous substrate 3 impregnated with the resin composition (resin varnish) 2 is heated under desired conditions, for example, at 80°C to 180°C for 1 minute to 10 minutes. By heating, a prepreg 1 in an uncured (A-stage) or semi-cured (B-stage) state is obtained. The heating also volatilizes the organic solvent from the resin varnish, reducing or eliminating the organic solvent.

[0129] The resin composition according to this embodiment is a resin composition that provides a cured product with low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a low coefficient of thermal expansion. Therefore, a prepreg including this resin composition or a semi-cured product of this resin composition provides a cured product with low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a low coefficient of thermal expansion. This prepreg can be used to suitably manufacture wiring boards that include an insulating layer containing a cured product with low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a low coefficient of thermal expansion.

[0130] [Metal-clad laminate] FIG. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate 11 according to an embodiment of the present invention.

[0131] As shown in FIG. 2, the metal-clad laminate 11 according to this embodiment includes an insulating layer 12 containing a cured product of the resin composition and a metal foil 13 disposed on the insulating layer 12. Examples of the metal-clad laminate 11 include a metal-clad laminate including an insulating layer 12 containing a cured product of the prepreg 1 shown in FIG. 1 and a metal foil 13 laminated together with the insulating layer 12. The insulating layer 12 may be formed from a cured product of the resin composition or a cured product of the prepreg. The thickness of the metal foil 13 varies depending on the performance required of the final wiring board and is not particularly limited. The thickness of the metal foil 13 can be appropriately set depending on 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. When the metal foil is thin, it may be a carrier-supported copper foil having a release layer and a carrier to improve handling.

[0132] The method for producing the metal-clad laminate 11 is not particularly limited as long as it can produce the metal-clad laminate 11. Specifically, a method for producing the metal-clad laminate 11 using the prepreg 1 can be used. Examples of such a method include a method in which one or more prepregs 1 are stacked, and then a metal foil 13 such as copper foil is stacked on both or one of the upper and lower surfaces of the prepreg 1, and the metal foil 13 and the prepreg 1 are heated and pressurized to form an integrated laminate, thereby producing a double-sided or single-sided metal foil-clad laminate 11. That is, the metal-clad laminate 11 is obtained by stacking the metal foil 13 on the prepreg 1 and then heating and pressurizing the resulting laminate. The heating and pressurizing conditions can be appropriately set depending on the thickness of the metal-clad laminate 11, the type of resin composition contained in the prepreg 1, and other factors. For example, the temperature can be 170 to 220°C, the pressure can be 3 to 4 MPa, and the time can be 60 to 150 minutes. The metal-clad laminate may also be produced without using a prepreg. For example, a method may be used in which a varnish-like resin composition is applied onto a metal foil to form a layer containing the resin composition on the metal foil, and then the layer is heated and pressed.

[0133] The resin composition according to the present embodiment is a resin composition that can produce a cured product with low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a low coefficient of thermal expansion. Therefore, a metal-clad laminate having an insulating layer containing a cured product of this resin composition is a metal-clad laminate having an insulating layer containing a cured product with low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a low coefficient of thermal expansion. This metal-clad laminate can then be used to suitably produce a wiring board having an insulating layer containing a cured product with low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a low coefficient of thermal expansion.

[0134] [Wiring board] FIG. 3 is a schematic cross-sectional view showing an example of wiring board 21 according to an embodiment of the present invention.

[0135] As shown in Fig. 3, wiring board 21 according to this embodiment has insulating layer 12 containing a cured product of the resin composition, and wiring 14 provided on insulating layer 12. Examples of wiring board 21 include a wiring board composed of insulating layer 12 used by curing prepreg 1 shown in Fig. 1, and wiring 14 laminated together with insulating layer 12 and formed by partially removing metal foil 13. Furthermore, insulating layer 12 may be made of a cured product of the resin composition, or may be made of a cured product of the prepreg.

[0136] The method for manufacturing the wiring board 21 is not particularly limited as long as the wiring board 21 can be manufactured. Specifically, a method for manufacturing the wiring board 21 using the prepreg 1 can be used. Examples of such a method include a method for manufacturing the wiring board 21 by etching the metal foil 13 on the surface of the metal-clad laminate 11 manufactured as described above to form wiring, thereby manufacturing the wiring board 21 having wiring provided as a circuit on the surface of the insulating layer 12. That is, the wiring board 21 can be obtained by forming a circuit by partially removing the metal foil 13 on the surface of the metal-clad laminate 11. In addition to the above methods, other methods for forming a circuit include circuit formation by a semi-additive process (SAP) or a modified semi-additive process (MSAP). The wiring board 21 is a wiring board having an insulating layer 12 containing a cured product with low dielectric properties, excellent heat resistance, and adhesion to the metal foil, and a low thermal expansion coefficient.

[0137] [Metal foil with resin] FIG. 4 is a schematic cross-sectional view showing an example of a resin-coated metal foil 31 according to this embodiment.

[0138] 4, the resin-coated metal foil 31 according to this embodiment comprises a resin layer 32 containing the resin composition or a semi-cured product of the resin composition, and a metal foil 13. The resin-coated metal foil 31 has the metal foil 13 on the surface of the resin layer 32. That is, the resin-coated metal foil 31 comprises the resin layer 32 and the metal foil 13 laminated together with the resin layer 32. The resin-coated metal foil 31 may also comprise another layer between the resin layer 32 and the metal foil 13.

[0139] The resin layer 32 may contain a semi-cured product of the resin composition as described above, or may contain the uncured resin composition. That is, the resin-coated metal foil 31 may comprise a resin layer containing a semi-cured product of the resin composition (the resin composition in B stage) and a metal foil, or a resin layer containing the resin composition before curing (the resin composition in A stage) and a metal foil. 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. The resin composition or the semi-cured product of the resin composition may be obtained by drying or heat-drying the resin composition. The fibrous substrate may be the same as the fibrous substrate of a prepreg.

[0140] The metal foil may be any metal foil used in a metal-clad laminate or a resin-coated metal foil, and examples of the metal foil include copper foil and aluminum foil.

[0141] The resin-coated metal foil 31 may be provided with a cover film or the like as necessary. By providing a cover film, it is possible to prevent the inclusion of foreign matter, etc. The cover film is not particularly limited, but examples thereof include polyolefin film, polyester film, polymethylpentene film, and films formed by providing a release agent layer on these films.

[0142] The method for producing the resin-coated metal foil 31 is not particularly limited as long as it can produce the resin-coated metal foil 31. Examples of methods for producing the resin-coated metal foil 31 include a method of 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, using a bar coater. The applied resin composition is heated, for example, at 80°C or higher and 180°C or lower, for 1 minute or longer and 10 minutes or shorter. The heated resin composition is formed on the metal foil 13 as an uncured resin layer 32. Note that the heating volatilizes the organic solvent from the resin varnish, thereby reducing or removing the organic solvent.

[0143] The resin composition according to this embodiment is a resin composition that provides a cured product with low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a low coefficient of thermal expansion. Therefore, a resin-coated metal foil having a resin layer containing this resin composition or a semi-cured product of this resin composition provides a cured product with low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a low coefficient of thermal expansion. This resin-coated metal foil can be used to manufacture a wiring board having an insulating layer that provides low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a low coefficient of thermal expansion. For example, by laminating the resin-coated metal foil on a wiring board, a multilayer wiring board can be manufactured. A wiring board obtained using such a resin-coated metal foil includes an insulating layer that provides low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a low coefficient of thermal expansion.

[0144] [Resin-coated film] FIG. 5 is a schematic cross-sectional view showing an example of a resin-coated film 41 according to the present embodiment.

[0145] 5, the resin-coated film 41 according to this embodiment includes a resin layer 42 containing the resin composition or a semi-cured product of the resin composition, and a support film 43. The resin-coated film 41 includes the resin layer 42 and the support film 43 laminated together with the resin layer 42. The resin-coated film 41 may also include another layer between the resin layer 42 and the support film 43.

[0146] The resin layer 42 may contain a semi-cured product of the resin composition as described above, or may contain the uncured resin composition. That is, the resin-coated film 41 may include a resin layer containing a semi-cured product of the resin composition (the resin composition in B stage) and a support film, or may be a resin-coated film including a resin layer containing the resin composition before curing (the resin composition in A stage) and a support film. 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. The resin composition or the semi-cured product of the resin composition may be obtained by drying or heat-drying the resin composition. The fibrous substrate may be the same as the fibrous substrate of a prepreg.

[0147] Any support film used for a resin-coated film can be used without limitation as the support film 43. Examples of the support film include electrically insulating films such as polyester film, polyethylene terephthalate (PET) film, polyimide film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, polyamide film, polycarbonate film, and polyarylate film.

[0148] The resin-coated film 41 may be provided with a cover film or the like as needed. By providing a cover film, it is possible to prevent the inclusion of foreign matter, etc. The cover film is not particularly limited, but examples thereof include a polyolefin film, a polyester film, and a polymethylpentene film.

[0149] The support film and the cover film may be subjected to surface treatment such as matte treatment, corona treatment, release treatment, and roughening treatment, if necessary.

[0150] The method for producing the resin-coated film 41 is not particularly limited as long as it can produce the resin-coated film 41. Examples of methods for producing the resin-coated film 41 include a method in which the varnish-like resin composition (resin varnish) is applied to a support film 43 and heated. The varnish-like resin composition is applied to the support film 43 using, for example, a bar coater. The applied resin composition is heated, for example, at a temperature of 80°C to 180°C for 1 minute to 10 minutes. The heated resin composition is formed on the support film 43 as an uncured resin layer 42. The heating volatilizes the organic solvent from the resin varnish, thereby reducing or removing the organic solvent.

[0151] The resin composition according to this embodiment is a resin composition that provides a cured product with low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a low thermal expansion coefficient. Therefore, a resin-attached film having a resin layer containing this resin composition or a semi-cured product of this resin composition provides a cured product with low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a low thermal expansion coefficient. This resin-attached film can be suitably used to manufacture a wiring board having an insulating layer that provides low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a cured product with a low thermal expansion coefficient. For example, a multilayer wiring board can be manufactured by laminating the resin-attached film on a wiring board and then peeling off the support film, or by laminating the resin-attached film on a wiring board after peeling off the support film. A wiring board obtained using such a resin-attached film provides a wiring board having an insulating layer that provides low dielectric properties, heat resistance, and excellent adhesion to metal foil, and a cured product with a low thermal expansion coefficient.

[0152] According to the present invention, there is provided a resin composition which can give a cured product having low dielectric properties, excellent heat resistance, and adhesion to metal foil, and a low coefficient of thermal expansion. Furthermore, according to the present invention, there are provided a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board, which are obtained using the resin composition.

[0153] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples. [Example]

[0154] [Examples 1 to 25 and Comparative Examples 1 to 6] In this example, each component used in preparing the resin composition will be described.

[0155] (Polyphenylene ether compounds: PPE) Modified PPE-1: a polyphenylene ether compound having a vinylbenzyl group (ethenylbenzyl group) at the end (OPE-2st 1200, Mn1200 manufactured by Mitsubishi Gas Chemical Company, Inc., a modified polyphenylene ether compound represented by the above formula (12), in which Ar2 in formula (12) is a phenylene group, R1 to R3 are hydrogen atoms, and p is 1) Modified PPE-2: a polyphenylene ether compound having a vinylbenzyl group (ethenylbenzyl group) at the end (OPE-2st 2200, Mn2200 manufactured by Mitsubishi Gas Chemical Company, Inc., a modified polyphenylene ether compound represented by the above formula (12), in which Ar2 in formula (12) is a phenylene group, R1 to R3 are hydrogen atoms, and p is 1) Modified PPE-3: A polyphenylene ether compound having a vinylbenzyl group (ethenylbenzyl group) at the end (a modified polyphenylene ether compound obtained by reacting polyphenylene ether with chloromethylstyrene).

[0156] Specifically, it is a modified polyphenylene ether compound obtained by the following reaction.

[0157] First, 200 g of polyphenylene ether (SA90 manufactured by SABIC Innovative Plastics, 2 terminal hydroxyl groups, weight-average molecular weight Mw 1700), 30 g of a 50:50 mass ratio mixture of p-chloromethylstyrene and m-chloromethylstyrene (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-neck flask equipped with a temperature controller, stirrer, cooling equipment, and dropping funnel, and the mixture was stirred. The mixture was then stirred until the polyphenylene ether, chloromethylstyrene, and tetra-n-butylammonium bromide were dissolved in the toluene. The mixture was gradually heated until the liquid temperature reached 75°C. An aqueous sodium hydroxide solution (20 g sodium hydroxide / 20 g water) was added dropwise to the solution as an alkali metal hydroxide over 20 minutes. The mixture was then stirred at 75°C for an additional 4 hours. Next, the contents of the flask were neutralized with 10% by mass of hydrochloric acid, and then a large amount of methanol was added. This caused a precipitate to form in the liquid in the flask. In other words, the product contained in the reaction solution in the flask was reprecipitated. This precipitate was then filtered, washed three times with a mixture of methanol and water in an 80:20 mass ratio, and then dried under reduced pressure at 80°C for 3 hours.

[0158] The obtained solid is 1 The solid was analyzed by H-NMR (400 MHz, CDCl3, TMS). As a result of NMR measurement, a peak derived from a vinylbenzyl group (ethenylbenzyl group) was confirmed at 5 to 7 ppm. This confirmed that the obtained solid was a modified polyphenylene ether compound having a vinylbenzyl group (ethenylbenzyl group) in the molecule as the substituent at the molecular end. Specifically, it was confirmed that it was an ethenylbenzylated polyphenylene ether. The obtained modified polyphenylene ether compound was represented by the above formula (13), in which Y in formula (13) was a dimethylmethylene group (represented by formula (11), and R in formula (11) 33 and R 34The compound was a modified polyphenylene ether compound in which Ar1 was a phenylene group, R1 to R3 were hydrogen atoms, and p was 1.

[0159] The number of terminal functional groups of the modified polyphenylene ether was measured as follows.

[0160] First, the modified polyphenylene ether was accurately weighed. The weight at that time was designated X (mg). Then, this weighed modified polyphenylene ether was dissolved in 25 mL of methylene chloride, and 100 μL of a 10 mass% ethanol solution of tetraethylammonium hydroxide (TEAH) (TEAH:ethanol (volume ratio) = 15:85) was added to the solution, and the absorbance (Abs) at 318 nm was measured using a UV spectrophotometer (UV-1600, manufactured by Shimadzu Corporation). Then, from the measurement results, the number of terminal hydroxyl groups of the modified polyphenylene ether was calculated using the following formula.

[0161] Residual OH amount (μmol / g) = [(25×Abs) / (ε×OPL×X)]×10 6 where ε is the extinction coefficient, 4700 L / mol cm, and OPL is the cell path length, 1 cm.

[0162] The calculated residual OH amount (number of terminal hydroxyl groups) of the modified polyphenylene ether was almost zero, which indicated that the hydroxyl groups of the polyphenylene ether before modification were almost entirely modified. This indicated that the decrease in the number of terminal hydroxyl groups from the polyphenylene ether before modification was the number of terminal hydroxyl groups of the polyphenylene ether before modification. In other words, it was found that the number of terminal hydroxyl groups of the polyphenylene ether before modification was the number of terminal functional groups of the modified polyphenylene ether. In other words, the number of terminal functional groups was two.

[0163] The intrinsic viscosity (IV) of the modified polyphenylene ether was measured in methylene chloride at 25°C. Specifically, the intrinsic viscosity (IV) of the modified polyphenylene ether was measured using a viscometer (AVS500 Visco System manufactured by Schott) for a 0.18 g / 45 ml methylene chloride solution (liquid temperature 25°C) of the modified polyphenylene ether. As a result, the intrinsic viscosity (IV) of the modified polyphenylene ether was 0.086 dL / g.

[0164] The molecular weight distribution of the modified polyphenylene ether was measured using GPC. The weight average molecular weight (Mw) was calculated from the obtained molecular weight distribution. As a result, Mw was 1,900.

[0165] Modified PPE-4: Modified polyphenylene ether in which the terminal hydroxyl group of polyphenylene ether is modified with a methacrylic group (represented by the above formula (14), in which Y in formula (14) is a dimethylmethylene group (represented by formula (11), in which R 33 and R 34 modified polyphenylene ether compound (wherein each methyl group is a group), SA9000 manufactured by SABIC Innovative Plastics, weight average molecular weight Mw 2000, number of terminal functional groups 2) Unmodified PPE: Polyphenylene ether (PPE) (SA90 manufactured by SABIC Innovative Plastics, intrinsic viscosity (IV) 0.083 dl / g, number of terminal hydroxyl groups 2, weight average molecular weight Mw 1700) (Maleimide compound (A)) Maleimide compound (A): A maleimide compound having an arylene structure in the molecule oriented at the meta position (solid content in MIR-5000-60T (a toluene solution of a maleimide compound) manufactured by Nippon Kayaku Co., Ltd., maleimide compound (A2) represented by the formula (2) above) (Inorganic filler) Silica: Silica particles surface-treated with a silane coupling agent containing a phenylamino group in the molecule (SC2500-SXJ manufactured by Admatechs Co., Ltd.) (hardening agent) Epoxy compound: dicyclopentadiene epoxy resin (HP-7200 manufactured by DIC Corporation) Maleimide compound (B)-1: A maleimide compound that does not have an arylene structure oriented at the meta position in the molecule (solid content in MIR-3000-70MT (maleimide compound dissolved in a methyl ethyl ketone-toluene mixed solvent) manufactured by Nippon Kayaku Co., Ltd., a biphenylaralkyl-type maleimide compound). Maleimide compound (B)-2: a maleimide compound that does not have an arylene structure bonded in a meta-oriented manner in the molecule (BMI-689, an N-alkyl bismaleimide compound manufactured by Designer Molecules Inc.) Maleimide compound (B)-3: a maleimide compound that does not have an arylene structure oriented at the meta position in the molecule (BMI-1500, an N-alkyl bismaleimide compound manufactured by Designer Molecules Inc.) Maleimide compound (B)-4: A maleimide compound not having an arylene structure oriented at the meta position in the molecule (BMI-4000 manufactured by Daiwa Chemical Industry Co., Ltd.) Allyl compound: triallyl isocyanurate (TAIC) (TAIC manufactured by Nippon Kasei Co., Ltd.) Methacrylate compound: Tricyclodecane dimethanol dimethacrylate (NK Ester DCP manufactured by Shin-Nakamura Chemical Co., Ltd.) Multifunctional vinyl compound: A liquid curable butadiene-styrene copolymer containing carbon-carbon unsaturated double bonds (Cray Valley Ricon 181). (thermoplastic styrene polymer) V9827: Hydrogenated methylstyrene (ethylene / butylene) methylstyrene copolymer (V9827 manufactured by Kuraray Co., Ltd., weight average molecular weight Mw 92000) FTR6125: styrene-based polymer (FTR6125 manufactured by Mitsui Chemicals, Inc., weight-average molecular weight Mw 1950, number-average molecular weight Mn 1150) (Reaction initiator) PBP: α,α'-di(t-butylperoxy)diisopropylbenzene (Perbutyl P (PBP) manufactured by NOF Corporation) (Reaction accelerator) 2E4MZ: 2-ethyl-4-methylimidazole (2E4MZ manufactured by Shikoku Chemicals Corporation)

[0166] [Preparation method] The varnish-like resin compositions (varnishes) of Examples 1 to 17, Examples 19 to 24, and Comparative Examples 1 to 6 were prepared as follows. First, each component other than the inorganic filler was added to toluene and mixed to a solids concentration of 50 mass% in the composition (parts by mass) shown in Tables 1 to 3. The mixture was stirred for 60 minutes. Thereafter, the filler was added to the resulting liquid, and the inorganic filler was dispersed using a bead mill. In this way, a varnish-like resin composition (varnish) was obtained. The varnish-like resin compositions (varnishes) of Examples 18 and 25 were obtained in the same manner as the varnish-like resin composition of Example 1, except that methyl ethyl ketone was used instead of toluene.

[0167] Next, a prepreg and an evaluation substrate (metal-clad laminate) were obtained as follows.

[0168] The obtained varnish was impregnated into a fibrous substrate (glass cloth: #1067 type, E-glass, manufactured by Nitto Boseki Co., Ltd.), and then heated and dried for 3 minutes at 130°C to produce a prepreg. At this time, the content of the components constituting the resin composition by the curing reaction relative to the prepreg (resin content) was adjusted to 74 mass%.

[0169] Next, an evaluation substrate (metal-clad laminate) was obtained as follows.

[0170] Eleven sheets of each prepreg were stacked, and copper foil (GTH-MP, 12 μm thick, manufactured by Furukawa Copper Foil Taiwan Co., Ltd.) was placed on both sides. This was used as a pressure body, and heated to 200°C at a temperature increase rate of 3°C / min, and then heated and pressed at 200°C for 120 minutes under a pressure of 4 MPa, to obtain an evaluation substrate (metal-clad laminate) with a thickness of approximately 830 μm and copper foil bonded to both sides.

[0171] The prepregs and evaluation substrates (metal-clad laminates) prepared as described above were evaluated by the methods described below.

[0172] [Thermal expansion coefficient] The copper foil was removed from the evaluation substrate (metal-clad laminate) by etching to prepare an unclad plate. The coefficient of thermal expansion (CTEz: ppm / °C) of the cured resin composition in the Z-axis direction was measured using the TMA method (Thermo-mechanical analysis) in accordance with IPC-TM-650 2.4.24. The measurement was performed using a TMA device (TMA6000 manufactured by SII Nano Technology Inc.) in the temperature range of 30 to 320°C.

[0173] [Glass transition temperature (Tg)] The copper foil was removed from the evaluation substrate (metal-clad laminate) by etching to prepare an unclad plate, which was used as a test specimen, and the Tg of the cured resin composition was measured using a viscoelasticity spectrometer "DMS6100" manufactured by Seiko Instruments Inc. Dynamic viscoelasticity measurement (DMA) was performed using a tensile module at a frequency of 10 Hz, and the temperature at which tan δ reached a maximum when the temperature was raised from room temperature to 320°C at a heating rate of 5°C / min was taken as Tg (°C).

[0174] [Peel Strength] The copper foil was peeled off from the evaluation substrate (metal-clad laminate), and the peel strength at this time was measured in accordance with JIS C 6481 (1996). Specifically, a pattern 10 mm wide and 100 mm long was formed on the evaluation substrate, and the copper foil was peeled off at a rate of 50 mm / min using a tensile tester, and the peel strength (N / mm) at this time was measured.

[0175] [Heat resistance] The heat resistance of the evaluation substrate (metal-clad laminate) was measured in accordance with the standard JIS C 6481 (1996). Specifically, the evaluation substrate (metal-clad laminate) was cut to a predetermined size to serve as a test piece. This test piece was left in a thermostatic chamber set at 280°C, 290°C, or 300°C for 1 hour, and then removed. The heat-treated test piece was visually inspected for the presence or absence of blistering. If no blistering was observed after heat treatment in a thermostatic chamber at 300°C, the test piece was evaluated as "◎". If blistering was observed after heat treatment in a thermostatic chamber at 300°C, but no blistering was observed after heat treatment in a thermostatic chamber at 290°C, the test piece was evaluated as "◯". If blistering was observed after heat treatment in a thermostatic chamber at 290°C, but no blistering was observed after heat treatment in a thermostatic chamber at 280°C, the test piece was evaluated as "△". When heat treatment was performed in a constant temperature bath at 280°C, if the occurrence of swelling was confirmed, it was evaluated as "X".

[0176] [Dielectric properties (relative permittivity and dielectric loss tangent)] The copper foil was removed from the evaluation substrate (metal-clad laminate) by etching to obtain an unclad board, which was used as a test specimen. The dielectric constant and dielectric loss tangent of the evaluation substrate at 10 GHz were measured using a cavity resonator perturbation method. Specifically, the dielectric constant and dielectric loss tangent of the evaluation substrate at 10 GHz were measured using a network analyzer (Keysight Technologies, Inc., N5230A).

[0177] The results of the above evaluations are shown in Tables 1 to 3.

[0178] [Table 1]

[0179] [Table 2]

[0180] [Table 3]

[0181] As can be seen from Tables 1 to 3, when resin compositions containing a polyphenylene ether compound having a carbon-carbon unsaturated double bond in the molecule were used, the resin compositions (Examples 1 to 25) containing a maleimide compound having an arylene structure bonded in a meta-oriented manner in the molecule (maleimide compound (A)) and an inorganic filler were used, compared to those without the maleimide compound. Cured products exhibited excellent heat resistance, such as a low coefficient of thermal expansion, high peel strength, and a high glass transition temperature, as well as low dielectric constant and dielectric loss tangent. Specifically, the resin composition of Example 2 had a low dielectric constant and dielectric loss tangent and a high peel strength, even when compared with the resin composition of Comparative Example 1, which was similar to Example 2, except that the resin composition contained maleimide compound (B)-1, which did not have an arylene structure bonded in a meta-oriented manner in the molecule, instead of maleimide compound (A). Furthermore, the resin composition of Example 2 had high peel strength, excellent heat resistance such as a high glass transition temperature, and low dielectric constant and dielectric dissipation factor, even when compared to a case (Comparative Example 2) in which unmodified PPE was used instead of a polyphenylene ether compound having a carbon-carbon unsaturated double bond in the molecule. Furthermore, when unmodified PPE was used and a reaction accelerator was added (Comparative Example 3), the peel strength and heat resistance were higher than those of Comparative Example 2. Even so, the resin composition of Example 2 had a low dielectric constant and dielectric dissipation factor, even when compared to Comparative Example 3. Furthermore, the resin composition of Example 2 not only had a low coefficient of thermal expansion but also poor dielectric properties compared to the resin composition of Comparative Example 1, which was similar to Example 2 but contained no inorganic filler. Furthermore, the resin composition of Example 2 not only had low heat resistance such as a glass transition temperature but also a low coefficient of thermal expansion compared to Comparative Example 5, which did not contain a maleimide compound. Furthermore, the resin composition of Example 2 had high peel strength compared to Comparative Example 6, which did not contain a polyphenylene ether compound having a carbon-carbon unsaturated double bond in the molecule. From these findings, it was found that the resin compositions of Examples 1 to 25 have excellent heat resistance, such as a low coefficient of thermal expansion, high peel strength, and high glass transition temperature, and can produce cured products with low relative dielectric constant and dielectric dissipation factor.

[0182] Furthermore, when the content of the maleimide compound (A) was 1 to 90 parts by mass relative to 100 parts by mass of the total mass of the polyphenylene ether compound and the maleimide compound (A) (Examples 6 to 12), the peel strength was higher than when the content of the maleimide compound (A) exceeded 90 parts by mass (Example 13). This indicates that a content of the maleimide compound (A) of 1 to 90 parts by mass is preferable in terms of improving adhesion to copper foil. Furthermore, Table 3 indicates that even when a curing agent or a thermoplastic styrene-based polymer is further added, a cured product having a low coefficient of thermal expansion, high peel strength, excellent heat resistance such as a high glass transition temperature, a low dielectric constant, and a low dielectric loss tangent can be obtained.

[0183] This application is based on Japanese Patent Application No. 2020-153177, filed on September 11, 2020, the contents of which are incorporated herein by reference.

[0184] In order to express the present invention, the present invention has been properly and sufficiently described through the embodiments in the above, but it should be recognized that those skilled in the art can easily change and / or improve the above-mentioned embodiments. Therefore, unless the changes or improvements made by those skilled in the art are at a level that causes departure from the scope of the claims described in the claims, such changes or improvements are interpreted as being included in the scope of the claims. [Industrial Applicability]

[0185] The present invention provides a resin composition that can give a cured product having low dielectric properties, excellent heat resistance, and adhesion to metal foil, and a low coefficient of thermal expansion. The present invention also provides a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board, which are obtained using the resin composition. [Explanation of symbols]

[0186] 1 Prepreg 2. Resin composition or semi-cured resin composition 3. Fibre base material 11 Metal-clad laminate 12 Insulating layer 13 Metal foil 14 Wiring 21 Wiring board 31 Resin-coated metal foil 32, 42 Resin layer 41 Resin-coated film 43 Support film

Claims

1. a polyphenylene ether compound having a carbon-carbon unsaturated double bond at its terminal; a maleimide compound (A) having an arylene structure in the molecule oriented and bonded at the meta position; and an inorganic filler, The content of the maleimide compound (A) in the resin composition is 5 to 50 parts by mass per 100 parts by mass of the total mass of the polyphenylene ether compound and the maleimide compound (A).

2. The resin composition according to claim 1 , wherein the maleimide compound (A) comprises a maleimide compound (A1) represented by the following formula (1): 【Chemistry 1】 [In formula (1), Ar １ represents an arylene group bonded in a meta orientation, and R Ａ , R Ｂ , R Ｃ , and R Ｄ each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group; R Ｅ , and R Ｆ each independently represents an aliphatic hydrocarbon group, and s represents 1 to 5.

3. The resin composition according to claim 2 , wherein the maleimide compound (A1) represented by the formula (1) includes a maleimide compound (A2) represented by the following formula (2): 【Chemistry 2】 [In formula (2), s represents 1 to 5.]

4. The resin composition according to any one of claims 1 to 3, wherein the polyphenylene ether compound comprises a polyphenylene ether compound having at least one selected from a group represented by the following formula (3) and a group represented by the following formula (4) at a molecular end: 【Transformation 3】 [In formula (3), R １ ~R ３ each independently represents a hydrogen atom or an alkyl group, Ar ２ represents an arylene group, and p represents an integer of 0 to 10. 【Chemistry 4】 [In formula (4), R ４ represents a hydrogen atom or an alkyl group.

5. 5. The resin composition according to claim 1, wherein the content of the maleimide compound (A) is 20 to 40 parts by mass per 100 parts by mass of the total mass of the polyphenylene ether compound and the maleimide compound (A).

6. further containing a curing agent that reacts with at least one of the polyphenylene ether compound and the maleimide compound (A), The resin composition according to any one of claims 1 to 5, wherein the curing agent comprises at least one selected from the group consisting of a maleimide compound (B) different from the maleimide compound (A), a methacrylate compound, an acrylate compound, a vinyl compound, a cyanate ester compound, and an allyl compound.

7. The resin composition according to claim 6, wherein the curing agent comprises an N-alkylmaleimide compound.

8. The resin composition according to any one of claims 1 to 7, further comprising a thermoplastic styrene-based polymer.

9. The resin composition according to any one of claims 1 to 8, further comprising a reaction initiator.

10. The resin composition according to claim 9 , wherein the reaction initiator comprises at least one selected from the group consisting of peroxides and organic azo compounds.

11. A prepreg comprising the resin composition according to any one of claims 1 to 10 or a semi-cured product of the resin composition and a fibrous base material.

12. A resin-coated film comprising a resin layer containing the resin composition according to any one of claims 1 to 10 or a semi-cured product of the resin composition, and a support film.

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

14. A metal-clad laminate comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 10 or a cured product of the prepreg according to claim 11, and a metal foil.

15. A wiring board comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 10 or a cured product of the prepreg according to claim 11, and wiring.

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