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

Abstract

One embodiment of the present invention is a resin composition that contains a maleimide compound, a polyphenylene ether compound having an unsaturated double bond in each molecule, and a phosphorus-containing compound having a group represented by formula (1) and a phosphorous-atom-including group in each molecule.　In formula (1), R1 represents a hydrogen atom or an alkyl group.

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] With the increase in the amount of information processed, various electronic devices are undergoing development in packaging technologies such as higher integration of mounted semiconductor devices, higher density wiring, and multi-layering. In addition, wiring boards used in various electronic devices are required to be high-frequency compatible wiring boards, such as millimeter wave radar boards for in-vehicle applications. Substrate materials for constituting the insulating layers of wiring boards used in various electronic devices are required to have low dielectric constants and dielectric loss tangents in order to increase the signal transmission speed and reduce loss during signal transmission.

[0003] Polyphenylene ether is known to have excellent low dielectric properties such as low dielectric constant and low dielectric loss tangent, and also has excellent low dielectric properties such as low dielectric constant and low dielectric loss tangent 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. More specifically, it is preferably used as a substrate material for constituting an insulating layer of a wiring board provided in an electronic device that uses a high frequency band.

[0004] Substrate materials for forming the insulating layer of a wiring board are required to have not only excellent low dielectric properties, but also to have high curability and to obtain a cured product with excellent heat resistance. For this reason, it is considered that the heat resistance can be improved by using a polyphenylene ether compound having an unsaturated double bond in the molecule as the substrate material. Examples of resin compositions containing such polyphenylene ether compounds having an unsaturated double bond in the molecule include the resin compositions described in Patent Document 1.

[0005] Patent Document 1 describes a curable resin composition containing a vinyl compound having a polyphenylene ether skeleton in the molecule and a maleimide compound having a specific structure. Patent Document 1 discloses that it is possible to obtain a curable resin composition that gives a cured product having a low dielectric constant, a low dielectric tangent, and excellent heat resistance, mechanical properties, chemical resistance, and flame retardancy, has excellent curability even in the presence of oxygen, and can be cured at low temperatures. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2009-161725 A Summary of the Invention

[0007] The present invention aims to provide a resin composition that has a high glass transition temperature, excellent flame retardancy, low water absorption, and can be used to obtain a cured product that sufficiently suppresses increases in dielectric constant and dielectric tangent due to water absorption even after water absorption, and has excellent moldability. 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 obtained using the resin composition.

[0008] One aspect of the present invention is a resin composition containing a maleimide compound, a polyphenylene ether compound having an unsaturated double bond in the molecule, a phosphorus-containing compound having a group represented by the following formula (1) and a group containing a phosphorus atom in the molecule, and a curing agent.

[0009] [ka] In formula (1), R1 represents a hydrogen atom or an alkyl group. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a prepreg according to an embodiment of the present invention. [Diagram 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. [Diagram 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 one example of a resin-coated metal foil according to an embodiment of the present invention. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing one example of a resin-coated film according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Wiring boards used in various electronic devices are also required to be less susceptible to changes in the external environment. For example, in order to be able to use the wiring board even in a high humidity environment, it is required that the substrate material for constituting the insulating layer of the wiring board is able to obtain a cured product with low water absorption. It is considered that the insulating layer of the wiring board obtained from the substrate material from which such a cured product with low water absorption can suppress moisture absorption. In addition, it is also required that the insulating layer of the wiring board is able to maintain low dielectric properties even if it absorbs water. For these reasons, it is required that the substrate material for constituting the insulating layer of the wiring board is able to obtain a cured product with low water absorption and that can maintain low dielectric properties even after absorbing water. That is, it is required that the substrate material for constituting the insulating layer of the wiring board is able to obtain a cured product that sufficiently suppresses the increase in dielectric constant and dielectric loss tangent due to water absorption. In addition, in order to be able to use the wiring board even in a relatively high temperature environment, it is required that the substrate material for constituting the insulating layer of the wiring board is able to obtain a cured product with excellent heat resistance, such as a high glass transition temperature. In addition, it is also required that the insulating layer provided on the wiring board does not deform even in a relatively high temperature environment. If the glass transition temperature of the insulating layer is high, the deformation is suppressed, so that the substrate material for forming the insulating layer of the wiring board is required to have a high glass transition temperature. In addition, the insulating layer of the wiring board is also required to have excellent flame retardancy from the viewpoint of fire prevention, etc. For this reason, the substrate material for forming the insulating layer of the wiring board is required to obtain a cured product having excellent flame retardancy.

[0012] As described above, the requirements for various properties of substrate materials for forming the insulating layer of a wiring board are increasing in order to cope with further developments in packaging technology such as higher integration of semiconductor devices, higher density wiring, and multi-layering, etc. The substrate materials are also required to have excellent formability in order to suitably form the insulating layer of the wiring board while satisfying such requirements.

[0013] As a result of extensive investigations, the present inventors have found that the present invention described below can suitably give a cured product which has a high glass transition temperature, excellent flame retardancy, low water absorption, and in which increases in dielectric constant and dielectric tangent due to water absorption are sufficiently suppressed even after water absorption, thereby achieving the above-mentioned objects, such as providing a resin composition with excellent moldability.

[0014] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these.

[0015] [Resin composition] The resin composition according to the present embodiment contains a maleimide compound, a polyphenylene ether compound having an unsaturated double bond in its molecule, a phosphorus-containing compound having a group represented by the following formula (1) and a group containing a phosphorus atom in its molecule, and a curing agent.

[0016] [ka] In formula (1), R1 represents a hydrogen atom or an alkyl group.

[0017] First, since the resin composition contains the polyphenylene ether compound, it is believed that by curing, a cured product that maintains the excellent low dielectric properties of polyphenylene ether can be obtained. In addition, by containing the polyphenylene ether compound, the maleimide compound, and the curing agent, the resin composition can be cured suitably, and a cured product that has a high glass transition temperature, low water absorption, and sufficiently suppresses the increase in dielectric constant and dielectric loss tangent due to water absorption even after water absorption can be obtained. That is, it is believed that the resin composition can obtain a cured product that can suitably maintain the excellent low dielectric properties of polyphenylene ether even after water absorption. In addition, since the phosphorus-containing compound has not only a group containing a phosphorus atom but also a group represented by the formula (1) in its molecule, it is believed that it can bond with the polyphenylene ether compound and the like when the resin composition is cured. It is believed that this can effectively increase the flame retardancy of the cured product. For this reason, it is believed that the phosphorus-containing compound can increase the flame retardancy with a relatively small amount, and therefore can sufficiently increase the flame retardancy of the cured product while suppressing the decrease in moldability of the resin composition.

[0018] From the above, the resin composition having the above-mentioned configuration is a resin composition which can suitably give a cured product having excellent moldability, a high glass transition temperature, excellent flame retardancy, low water absorption, and in which increases in dielectric constant and dielectric tangent due to water absorption are sufficiently suppressed even after water absorption.

[0019] When a wiring board is manufactured using such a resin composition, a wiring board having an insulating layer suitably formed of a cured product having a high glass transition temperature, excellent flame retardancy, low water absorption, and sufficient suppression of increases in dielectric constant and dielectric loss tangent due to water absorption even after water absorption, and excellent flame retardancy, can be obtained. For this reason, the wiring board can be used even in a high humidity environment, for example, because it has an insulating layer that has low water absorption and sufficiently suppresses increases in dielectric constant and dielectric loss tangent due to water absorption even after water absorption. In addition, a wiring board having an insulating layer with a high glass transition temperature can be obtained. For this reason, not only is the insulating layer highly heat-resistant, but deformation of the insulating layer can also be sufficiently suppressed, so that it can be used even in a high temperature environment. Furthermore, when such a wiring board is, for example, a multi-layer wiring board, deformation of the wiring board can be sufficiently suppressed during the reflow cycle process in which components are mounted on the multi-layer wiring board. In order to sufficiently suppress this deformation, it is preferable that the glass transition temperature is 260 ° C. or higher. And, by suppressing the deformation here, for example, warping of the wiring board due to temperature changes in the reflow process can be suppressed. Furthermore, it is possible to suppress the occurrence of component mounting defects on a multilayer wiring board, cracks occurring in conductive vias in the multilayer wiring board, and connection defects in interlayer vias in the multilayer wiring board. Also, a wiring board having an insulating layer with excellent flame retardancy can be obtained. The resin composition has excellent moldability, so that the above-mentioned wiring board can be suitably manufactured.

[0020] (Maleimide compounds) The maleimide compound is not particularly limited as long as it has a maleimide group in the molecule. Examples of the maleimide compound include monofunctional maleimide compounds having one maleimide group in the molecule and polyfunctional maleimide compounds having two or more maleimide groups in the molecule. Examples of the monofunctional maleimide compound include chlorophenylmaleimides such as o-chlorophenylmaleimide, methylphenylmaleimide such as o-methylphenylmaleimide, hydroxyphenylmaleimide such as p-hydroxyphenylmaleimide, carboxyphenylmaleimide such as p-carboxyphenylmaleimide, N-dodecylmaleimide, and phenylmethanemaleimide. Examples of the polyfunctional maleimide compound include 4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide and other phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane, 4,4'-diphenyl ether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, and maleimide compounds represented by the following formula (3). Of these, the maleimide compounds are preferably the maleimide compounds represented by the following formula (3) and polyphenylmethane maleimide. The maleimide compounds may be used alone or in combination of two or more kinds.

[0021] [ka] In formula (3), s represents 1 to 5; 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.

[0022] In the maleimide compound represented by the formula (3), the repeat number s is 1 to 5, and preferably more than 1 and not more than 5. This s is the average value of the repeat number (degree of polymerization). A , R B , R C , and R D may be the same or different groups. A , R B , R C , and R D As described above, represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and among these, a hydrogen atom is preferable. 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.

[0023] Specifically, the molecular weight of the maleimide compound represented by the formula (3) is preferably a number average molecular weight of 150 to 2000, more preferably 400 to 1300. The weight average molecular weight is preferably 150 to 2500, more preferably 400 to 1500. The maleimide compound represented by the formula (3) preferably has a bifunctional content of 30 to 70 mass%, more preferably 50 to 70 mass% in the maleimide compound represented by the formula (3) where s is 1. The maleimide compound represented by the formula (3) preferably has a trifunctional or higher polyfunctional content of 2 or more in the formula (3) where s is 2 or more in the maleimide compound represented by the formula (3) where s is 30 to 70 mass%, more preferably 30 to 50 mass%. The maleimide compound represented by the formula (3) may contain a monofunctional substance represented by 0 in the formula (3) or a polyfunctional substance such as a heptafunctional substance or an octafunctional substance represented by 6 or more in the formula (3) as long as the average value of the repeat number (degree of polymerization) is 1 to 5.

[0024] (Polyphenylene ether compound) The polyphenylene ether compound is not particularly limited as long as it is a polyphenylene ether compound having an unsaturated double bond in the molecule. Examples of the polyphenylene ether compound include a polyphenylene ether compound having a substituent having an unsaturated double bond at the molecular end, such as a modified polyphenylene ether compound whose end is modified with a substituent having an unsaturated double bond.

[0025] The substituent having an unsaturated double bond is not particularly limited, and examples of the substituent include a substituent represented by the following formula (4) and a substituent represented by the following formula (5).

[0026] [ka] In formula (4), p represents an integer of 0 to 10. Z represents an arylene group. R2 to R4 are each independent. That is, R2 to R4 may be the same group or different groups. R2 to R4 represent a hydrogen atom or an alkyl group.

[0027] In addition, in the formula (4), when p is 0, it means that Z is directly bonded to the end of the polyphenylene ether.

[0028] The arylene group is not particularly limited. Examples of the arylene group include monocyclic aromatic groups such as phenylene groups, and polycyclic aromatic groups in which the aromatic ring is not monocyclic but is polycyclic aromatic such as naphthalene ring. The arylene group also includes derivatives in which a hydrogen atom bonded to the aromatic ring is substituted with a functional group such as an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. The alkyl group is not particularly limited, and is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0029] [ka] In formula (5), R5 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, 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.

[0030] A preferred specific example of the substituent represented by the formula (4) is a substituent containing a vinylbenzyl group. An example of the substituent containing a vinylbenzyl group is a substituent represented by the following formula (6). An example of the substituent represented by the formula (5) is an acryloyl group or a methacryloyl group.

[0031] [ka]

[0032] More specifically, the substituent includes vinylbenzyl groups (ethenylbenzyl groups) such as o-ethenylbenzyl groups, p-ethenylbenzyl groups, and m-ethenylbenzyl groups, vinylphenyl groups, acryloyl groups, and methacryloyl groups. The polyphenylene ether compound may have one type of the substituent, or two or more types. The polyphenylene ether compound may have, for example, any one of o-ethenylbenzyl groups, p-ethenylbenzyl groups, and m-ethenylbenzyl groups, or may have two or three types of these.

[0033] 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 (7) in the molecule.

[0034] [ka] In formula (7), t represents 1 to 50. R6 to R9 are each independent. That is, R6 to R9 may be the same group or different groups. R6 to R9 represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. Among these, a hydrogen atom and an alkyl group are preferred.

[0035] Specific examples of the functional groups mentioned in R6 to R9 include the following.

[0036] The alkyl group is not particularly limited, but is preferably, for example, an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0037] 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.

[0038] The alkynyl group is not particularly limited, but for example, an alkynyl group having 2 to 18 carbon atoms is preferable, and an alkynyl group having 2 to 10 carbon atoms is more preferable. Specific examples include an ethynyl group, a prop-2-yn-1-yl group (propargyl group), and the like.

[0039] The alkylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkyl group, and is preferably, for example, an alkylcarbonyl group having 2 to 18 carbon atoms, and more preferably an alkylcarbonyl group having 2 to 10 carbon atoms. 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.

[0040] 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 preferable, and an alkenylcarbonyl group having 3 to 10 carbon atoms is more preferable. Specific examples include an acryloyl group, a methacryloyl group, and a crotonoyl group.

[0041] 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 preferable, and an alkynylcarbonyl group having 3 to 10 carbon atoms is more preferable. Specific examples include a propioloyl group.

[0042] The weight average molecular weight (Mw) of the polyphenylene ether compound is not particularly limited. Specifically, it is preferably 500 to 5000, more preferably 800 to 4000, and further preferably 1000 to 3000. The weight average molecular weight may be measured by a general molecular weight measurement method, and specifically, it may be a value measured using gel permeation chromatography (GPC). In addition, when the polyphenylene ether compound has a repeating unit represented by the formula (7) in the molecule, t is preferably a numerical value that causes the weight average molecular weight of the polyphenylene ether compound to be within such a range. Specifically, t is preferably 1 to 50.

[0043] When the weight average molecular weight of the polyphenylene ether compound is within such a range, it has the excellent low dielectric properties of polyphenylene ether, and the heat resistance of the cured product is excellent, as well as the moldability. This is believed to be due to the following. When the weight average molecular weight of a normal polyphenylene ether is within such a range, the cured product tends to have a lower heat resistance because of its relatively low molecular weight. In this respect, since the polyphenylene ether compound according to the present embodiment has an unsaturated double bond at the end, it is believed that the cured product has a sufficiently high heat resistance. In addition, when the weight average molecular weight of the polyphenylene ether compound is within such a range, it is believed that the moldability is excellent because of its relatively low molecular weight. Therefore, it is believed that such a polyphenylene ether compound not only has a higher heat resistance of the cured product, but also has excellent moldability.

[0044] The average number of the substituents (number of terminal functional groups) at the molecular end 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 is difficult to obtain a cured product with sufficient heat resistance. If the number of terminal functional groups is too large, the reactivity becomes too high, and there is a possibility that problems such as, for example, deterioration in the storage stability of the resin composition or deterioration in the fluidity of the resin composition may occur. That is, when such a polyphenylene ether compound is used, there is a possibility that molding defects such as the generation of voids during multilayer molding may occur due to insufficient fluidity, and a highly reliable printed wiring board may be difficult to obtain.

[0045] The number of terminal functional groups of the polyphenylene ether compound may be 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 obtained polyphenylene ether compound and calculating the reduction from the number of hydroxyl groups of the polyphenylene ether before it has the substituents (before modification). The reduction from the number of hydroxyl groups of 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 mixed solution.

[0046] The intrinsic viscosity of the polyphenylene ether compound is not particularly limited. Specifically, it is preferably 0.03 to 0.12 dl / g, more preferably 0.04 to 0.11 dl / g, and even more preferably 0.06 to 0.095 dl / g. If the intrinsic viscosity is too low, the molecular weight tends to be low, and low dielectric properties such as low dielectric constant and low dielectric loss tangent tend to be difficult to obtain. If the intrinsic viscosity is too high, the viscosity is high, sufficient fluidity cannot be obtained, and the moldability of the cured product tends to decrease. Therefore, if the intrinsic viscosity of the polyphenylene ether compound is within the above range, excellent heat resistance and moldability of the cured product can be realized.

[0047] The intrinsic viscosity here is the intrinsic viscosity measured in methylene chloride at 25° C., and more specifically, for example, the value measured by a viscometer using a 0.18 g / 45 ml methylene chloride solution (liquid temperature 25° C.) As the viscometer, for example, the AVS500 Visco System manufactured by Schott Corporation can be mentioned.

[0048] Examples of the polyphenylene ether compound include a polyphenylene ether compound represented by the following formula (8) and a polyphenylene ether compound represented by the following formula (9). As the polyphenylene ether compound, these polyphenylene ether compounds may be used alone or in combination of these two types of polyphenylene ether compounds.

[0049] [ka]

[0050] [ka]

[0051] In formula (8) and formula (9), R 10 ~R 17 And R 18 ~R 25 each independently 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 each independently represent a substituent having a carbon-carbon unsaturated double bond. A and B represent repeating units represented by the following formula (10) and formula (11), respectively. In addition, in formula (9), Y represents a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms.

[0052] [ka]

[0053] [ka]

[0054] In the formulas (10) and (11), m and n each represent an integer of 0 to 20. 26 ~R 29 And R 30 ~R 33each independently 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.

[0055] The polyphenylene ether compound represented by the formula (8) and the polyphenylene ether compound represented by the formula (9) are not particularly limited as long as they satisfy the above-mentioned constitution. 10 ~R 17 And R 18 ~R 25 are independent of each other as described above. That is, R 10 ~R 17 And R 18 ~R 25 may be the same or different groups. 10 ~R 17 And R 18 ~R 25 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.

[0056] In the formula (10) and the formula (11), m and n each preferably represent a value of 0 to 20 as described above. In addition, it is preferable that m and n represent a value such that the sum of m and n is 1 to 30. Therefore, it is more preferable that m represents a value of 0 to 20, n represents a value of 0 to 20, and the sum of m and n represents a value of 1 to 30. In addition, R 26 ~R 29 And R 30 ~R 33 are independent of each other. That is, R 26 ~R 29 And R 30 ~R 33 may be the same or different groups. 26 ~R 29 And R 30 ~R 33represents 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.

[0057] R 10 ~R 33 are the same as R6 to R9 in the above formula (7).

[0058] In the formula (9), as described above, Y is a linear, branched, or cyclic hydrocarbon having a carbon number of 20 or less. Examples of Y include a group represented by the following formula (12).

[0059] [ka] In the formula (12), R 34 and R 35 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 (12) include a methylene group, a methylmethylene group, and a dimethylmethylene group, and among these, a dimethylmethylene group is preferred.

[0060] In the formula (8) and the formula (9), X1 and X2 are each independently a substituent having an unsaturated double bond. The substituents X1 and X2 are not particularly limited as long as they are a substituent having an unsaturated double bond. Examples of the substituents X1 and X2 include the substituents represented by the above formula (4) and the substituents represented by the above formula (5). In the polyphenylene ether compound represented by the formula (8) and the polyphenylene ether compound represented by the formula (9), X1 and X2 may be the same or different substituents.

[0061] A more specific example of the polyphenylene ether compound represented by the formula (8) includes a polyphenylene ether compound represented by the following formula (13).

[0062] [ka]

[0063] More specific examples of the polyphenylene ether compound represented by the formula (9) include a polyphenylene ether compound represented by the following formula (14) and a polyphenylene ether compound represented by the following formula (15).

[0064] [ka]

[0065] [ka]

[0066] In the above formulas (13) to (15), m and n are the same as m and n in the above formulas (10) and (11). In addition, in the above formulas (13) and (14), R2 to R4, p and Z are the same as R2 to R4, p and Z in the above formula (4). In addition, in the above formulas (14) and (15), Y is the same as Y in the above formula (9). In addition, in the above formula (15), R5 is the same as R4 in the above formula (5).

[0067] The synthesis method of the polyphenylene ether compound used in this embodiment is not particularly limited as long as it can synthesize a polyphenylene ether compound having an unsaturated double bond in the molecule. Here, a method for synthesizing a modified polyphenylene ether compound whose terminal is modified by a substituent having an unsaturated double bond will be described. Specifically, this method includes a method of reacting a compound in which a substituent having an unsaturated double bond and a halogen atom are bonded to a polyphenylene ether.

[0068] Examples of the compound in which a substituent having an unsaturated double bond is bonded to a halogen atom include compounds in which a substituent represented by the formulas (4) to (6) is bonded to a halogen atom. Specific examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom, and among these, a chlorine atom is preferred. More specific examples of the compound in which a substituent having an unsaturated double bond is bonded to a halogen atom include o-chloromethylstyrene, p-chloromethylstyrene, and m-chloromethylstyrene. The compound in which a substituent having an unsaturated double bond is bonded to a halogen atom may be used alone or in combination of two or more. For example, o-chloromethylstyrene, p-chloromethylstyrene, and m-chloromethylstyrene may be used alone or in combination of two or three.

[0069] The raw material polyphenylene ether is not particularly limited as long as it can finally synthesize a predetermined modified polyphenylene ether compound. Specifically, polyphenylene ethers composed of 2,6-dimethylphenol and at least one of a bifunctional phenol and a trifunctional phenol, and poly(2,6-dimethyl-1,4-phenylene oxide) and the like, which are mainly composed of polyphenylene ether, can be mentioned. In addition, the bifunctional phenol is a phenolic compound having two phenolic hydroxyl groups in the molecule, for example, tetramethylbisphenol A, etc. In addition, the trifunctional phenol is a phenolic compound having three phenolic hydroxyl groups in the molecule.

[0070] The modified polyphenylene ether compound can be synthesized by the above-mentioned method. Specifically, the above-mentioned polyphenylene ether and a compound in which a substituent having an 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, and the modified polyphenylene ether compound used in the present embodiment is obtained.

[0071] The reaction is preferably carried out in the presence of an alkali metal hydroxide. By doing so, it is believed that the reaction proceeds favorably. This is believed to be because the alkali metal hydroxide functions as a dehydrohalogenation agent, specifically, a dehydrochlorination agent. That is, it is believed that the alkali metal hydroxide removes hydrogen halide from the phenol group of the polyphenylene ether and the compound in which a substituent having a carbon-carbon unsaturated double bond and a halogen atom are bonded, and thereby the substituent having a carbon-carbon unsaturated double bond is bonded to the oxygen atom of the phenol group instead of the hydrogen atom of the phenol group of the polyphenylene ether.

[0072] 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.

[0073] The reaction conditions such as reaction time and reaction temperature vary depending on the compound in which a substituent having a carbon-carbon unsaturated double bond is bonded to a halogen atom, and are not particularly limited as long as the reaction proceeds favorably under the conditions. 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.

[0074] 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 and the like.

[0075] 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. It is believed that the above reaction proceeds more favorably by doing so. This is believed to be due to the following. It is believed that the phase transfer catalyst is a catalyst that has the function of incorporating an alkali metal hydroxide, is soluble in both a polar solvent phase such as water and a non-polar solvent phase such as an organic solvent, and can move between these phases. Specifically, when an aqueous sodium hydroxide solution is used as the alkali metal hydroxide and an organic solvent such as toluene, which is not compatible with water, is used as the solvent, even if the aqueous sodium hydroxide solution is dropped into the solvent being used for the reaction, the solvent and the aqueous sodium hydroxide solution are separated, and it is believed that the sodium hydroxide is unlikely to move to the solvent. In that case, it is believed that the aqueous sodium hydroxide solution 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 in the phase transfer catalyst, and the aqueous sodium hydroxide solution is likely to contribute 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 believed to proceed more favorably.

[0076] The phase transfer catalyst is not particularly limited, but examples thereof include quaternary ammonium salts such as tetra-n-butylammonium bromide.

[0077] The resin composition used in the present embodiment preferably contains, as the polyphenylene ether compound, the modified polyphenylene ether compound obtained as described above.

[0078] (phosphorus-containing compounds) The phosphorus-containing compound is not particularly limited as long as it has a group represented by the formula (1) and a group containing a phosphorus atom in the molecule.

[0079] As described above, R1 in the group represented by the formula (1) is a hydrogen atom or an alkyl group. Examples of the alkyl group include alkyl groups having 1 to 5 carbon atoms, specifically, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl, and neopentyl groups. Among these, hydrogen and methyl groups are preferred, and methyl groups are more preferred. That is, the group represented by the formula (1) is preferably an acryloyl group or a methacryloyl group, and more preferably a methacryloyl group.

[0080] The group containing a phosphorus atom is not particularly limited as long as it contains a phosphorus atom. Examples of the group containing a phosphorus atom include a phosphate group, a phosphoryl group, a group represented by the following formula (2), a group represented by the following formula (16), and a group represented by the following formula (17), and among these, the group represented by the following formula (2) is preferred.

[0081] [ka]

[0082] [ka] In formula (16), R 36 and R 37 each independently represents an alkyl group. Examples of the alkyl group 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, and among these, an ethyl group is preferable.

[0083] [ka]

[0084] The group containing a phosphorus atom may be directly bonded to the group represented by formula (1) or indirectly bonded (through another atom or the like). When indirectly bonded to the group represented by formula (1), the group containing a phosphorus atom and the group represented by formula (1) may be bonded to, for example, a carbon atom or an oxygen atom.

[0085] Examples of the phosphorus-containing compound containing a group represented by the formula (2) include compounds represented by the following formula (18).

[0086] [ka] In formula (18), R1 represents a hydrogen atom or an alkyl group, as in formula (1). Examples of the alkyl group include alkyl groups having 1 to 5 carbon atoms, and specifically 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. Among these, R1 is preferably a hydrogen atom or a methyl group, and more preferably a methyl group. That is, the phosphorus-containing compound is preferably (methacryloylmethyl)diphenylphosphine oxide.

[0087] (hardening agent) The curing agent is a curing agent capable of reacting with the maleimide compound and the polyphenylene ether compound to cure the resin composition containing the maleimide compound and the polyphenylene ether compound. The curing agent is not particularly limited as long as it is a curing agent capable of curing the resin composition containing the maleimide compound and the polyphenylene ether compound. Examples of the curing agent include styrene, styrene derivatives, compounds having an acryloyl group in the molecule, compounds having a methacryloyl group in the molecule, compounds having a vinyl group in the molecule, compounds having an allyl group in the molecule, compounds having an acenaphthylene structure in the molecule, and isocyanurate compounds having an isocyanurate group in the molecule.

[0088] Examples of the styrene derivatives include bromostyrene and dibromostyrene.

[0089] The compound having an acryloyl group in the molecule is an acrylate compound. The acrylate compound includes a monofunctional acrylate compound having one acryloyl group in the molecule, and a polyfunctional acrylate compound having two or more acryloyl groups in the molecule. The monofunctional acrylate compound includes, for example, methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. The polyfunctional acrylate compound includes, for example, a diacrylate compound such as tricyclodecane dimethanol diacrylate.

[0090] The compound having a methacryloyl group in the molecule is a methacrylate compound. The methacrylate compound may be a monofunctional methacrylate compound having one methacryloyl group in the molecule, or a polyfunctional methacrylate compound having two or more methacryloyl groups in the molecule. The monofunctional methacrylate compound may be, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. The polyfunctional methacrylate compound may be, for example, a dimethacrylate compound such as tricyclodecane dimethanol dimethacrylate.

[0091] The compound having a vinyl group in the molecule is a vinyl compound. The vinyl compound includes 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. The polyfunctional vinyl compound includes, for example, divinylbenzene and polybutadiene.

[0092] The compound having an allyl group in the molecule is an allyl compound. The allyl compound includes a monofunctional allyl compound having one allyl group in the molecule, and a polyfunctional allyl compound having two or more allyl groups in the molecule. The polyfunctional allyl compound includes, for example, a triallyl isocyanurate compound, a diallyl bisphenol compound, and diallyl phthalate (DAP).

[0093] The compound having an acenaphthylene structure in the molecule is an acenaphthylene compound. Examples of the acenaphthylene compound include acenaphthylene, alkylacenaphthylenes, halogenated acenaphthylenes, and phenylacenaphthylenes. Examples of the alkylacenaphthylenes include 1-methylacenaphthylene, 3-methylacenaphthylene, 4-methylacenaphthylene, 5-methylacenaphthylene, 1-ethylacenaphthylene, 3-ethylacenaphthylene, 4-ethylacenaphthylene, and 5-ethylacenaphthylene. Examples of the halogenated acenaphthylenes include 1-chloroacenaphthylene, 3-chloroacenaphthylene, 4-chloroacenaphthylene, 5-chloroacenaphthylene, 1-bromoacenaphthylene, 3-bromoacenaphthylene, 4-bromoacenaphthylene, and 5-bromoacenaphthylene. Examples of the phenylacenaphthylenes include 1-phenylacenaphthylene, 3-phenylacenaphthylene, 4-phenylacenaphthylene, and 5-phenylacenaphthylene. The acenaphthylene compound may be a monofunctional acenaphthylene compound having one acenaphthylene structure in the molecule as described above, or a polyfunctional acenaphthylene compound having two or more acenaphthylene structures in the molecule.

[0094] The compound having an isocyanurate group in the molecule is an isocyanurate compound. Examples of the isocyanurate compound include compounds further having an alkenyl group in the molecule (alkenyl isocyanurate compounds), such as triallyl isocyanurate (TAIC) and other trialkenyl isocyanurate compounds.

[0095] Among the above, the curing agent is preferably, for example, an allyl compound having an allyl group in the molecule, a polyfunctional acrylate compound having two or more acryloyl groups in the molecule, and a polyfunctional methacrylate compound having two or more methacryloyl groups in the molecule. The curing agent preferably contains the allyl compound, and more preferably contains the allyl compound and further contains a curing agent other than the allyl compound. The curing agent other than the allyl compound is preferably at least one of a polyfunctional acrylate compound and a polyfunctional methacrylate compound. That is, the curing agent is more preferably contains the allyl compound and further contains at least one of a polyfunctional acrylate compound and a polyfunctional methacrylate compound. The allyl compound is preferably a triallyl isocyanurate compound and a diallyl bisphenol compound. The polyfunctional methacrylate compound is preferably a dimethacrylate compound. In addition, when the curing agent contains the allyl compound and further contains a curing agent other than the allyl compound, the content of the allyl compound is preferably 50 to 99 parts by mass, and more preferably 60 to 85 parts by mass, per 100 parts by mass of the curing agent (the total of the allyl compound and the curing agent other than the allyl compound).

[0096] The curing agent may be used alone or in combination of two or more kinds.

[0097] 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 further preferably 100 to 3000. If the weight average molecular weight of the curing agent is too low, the curing agent may be easily volatilized from the compounding components of the resin composition. If the weight average molecular weight of the curing agent is too high, the viscosity of the varnish of the resin composition and the melt viscosity during heat molding may be too high. Therefore, if the weight average molecular weight of the curing agent is within such a range, a resin composition having excellent heat resistance of the cured product can be obtained. This is considered to be because the resin composition containing the polyphenylene ether compound can be suitably cured by the reaction with the polyphenylene ether compound. Here, the weight average molecular weight may be measured by a general molecular weight measurement method, and specifically, a value measured using gel permeation chromatography (GPC) may be mentioned.

[0098] The curing agent has an average number of functional groups per molecule that contribute to the reaction with the maleimide compound and the polyphenylene ether compound (number of functional groups), which varies depending on the weight-average molecular weight of the curing agent, and is preferably 1 to 20, more preferably 2 to 18. If the number of functional groups is too small, it tends to be difficult to obtain a cured product with sufficient heat resistance. If the number of functional groups is too large, the reactivity becomes too high, and there is a risk of problems such as a decrease in the storage stability of the resin composition or a decrease in the flowability of the resin composition.

[0099] (Content) The content of the phosphorus-containing compound is preferably 2 to 20 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 3 to 12 parts by mass, relative to 100 parts by mass of the total of the maleimide compound, the polyphenylene ether compound, and the curing agent. The content of the maleimide compound is preferably 10 to 75 parts by mass, more preferably 20 to 65 parts by mass, and even more preferably 30 to 50 parts by mass, relative to 100 parts by mass of the total of the maleimide compound, the polyphenylene ether compound, and the curing agent. The content of the polyphenylene ether compound is preferably 10 to 75 parts by mass, more preferably 20 to 60 parts by mass, and even more preferably 30 to 50 parts by mass, relative to 100 parts by mass of the total of the maleimide compound, the polyphenylene ether compound, and the curing agent. The content of the curing agent is preferably 10 to 45 parts by mass, more preferably 15 to 40 parts by mass, and even more preferably 20 to 35 parts by mass, relative to 100 parts by mass in total of the maleimide compound, the polyphenylene ether compound, and the curing agent. When the contents of the phosphorus-containing compound, the maleimide compound, the polyphenylene ether compound, and the curing agent are within the above ranges, a cured product having a high glass transition temperature, low water absorption, and sufficient suppression of increases in dielectric constant and dielectric loss tangent due to water absorption even after water absorption, and excellent flame retardancy can be suitably obtained, and a resin composition with excellent moldability can be obtained.

[0100] (Other Ingredients) The resin composition according to the present embodiment may contain components (other components) other than the phosphorus-containing compound, the maleimide compound, the polyphenylene ether compound, and the curing agent, as necessary, 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 further contain additives such as, for example, a silane coupling agent, an initiator, an antifoaming agent, an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a dye or pigment, a lubricant, and a filler. In addition to the polyphenylene ether compound, the resin composition may contain a thermosetting resin such as an epoxy resin, an unsaturated polyester resin, and a thermosetting polyimide resin.

[0101] The resin composition according to the present embodiment may contain a silane coupling agent as described above. The silane coupling agent may be contained in the resin composition, or may be contained in the inorganic filler contained in the resin composition as a silane coupling agent that has been surface-treated in advance. Among these, the silane coupling agent is preferably contained in the inorganic filler as a silane coupling agent that has been surface-treated in advance, and it is more preferable to contain the silane coupling agent in the inorganic filler as a silane coupling agent that has been surface-treated in advance, 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 in the fibrous base material as a silane coupling agent that has been surface-treated in advance.

[0102] Examples of the silane coupling agent include silane coupling agents having at least one functional group selected from the group consisting of vinyl, styryl, methacryloyl, acryloyl, and phenylamino groups. That is, the silane coupling agent includes compounds having at least one reactive functional group selected from vinyl, styryl, methacryloyl, acryloyl, and phenylamino groups, and further having hydrolyzable groups such as methoxy and ethoxy groups.

[0103] The silane coupling agent includes, for example, vinyl triethoxysilane and vinyl trimethoxysilane, which have a vinyl group. The silane coupling agent includes, for example, p-styryl trimethoxysilane and p-styryl triethoxysilane, which have a styryl group. The silane coupling agent includes, for example, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyl methyl dimethoxysilane, 3-methacryloxypropyl triethoxysilane, 3-methacryloxypropyl methyl diethoxysilane, and 3-methacryloxypropyl ethyl diethoxysilane, which have a methacryloyl group. The silane coupling agent includes, for example, 3-acryloxypropyl trimethoxysilane and 3-acryloxypropyl triethoxysilane, which have an acryloyl group. Examples of the silane coupling agent include those having a phenylamino group, such as N-phenyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltriethoxysilane.

[0104] As described above, the resin composition according to the present embodiment may contain a flame retardant other than the phosphorus-containing compound. That is, by using a flame retardant other than the phosphorus-containing compound in combination with the phosphorus-containing compound, the flame retardancy of the cured product of the resin composition can be increased. 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 having a melting point of 300° C. or more are preferred. It is considered that the use of a halogen-based flame retardant can suppress the elimination of halogen at high temperatures and suppress the decrease in heat resistance. In addition, in fields where halogen-free is required, phosphate ester-based flame retardants, phosphazene-based flame retardants, bisdiphenylphosphine oxide-based flame retardants, and phosphinate-based flame retardants can be mentioned. Specific examples of phosphate ester-based flame retardants include phosphate ester compounds such as condensed phosphate esters of dixylenyl phosphate and aromatic condensed phosphate ester compounds. A specific example of the phosphazene flame retardant is phenoxyphosphazene. A specific example of the bisdiphenylphosphine oxide flame retardant is xylylenebisdiphenylphosphine oxide. A specific example of the phosphinate flame retardant is, for example, a phosphinate metal salt of aluminum dialkylphosphinate and a phosphinate compound such as aluminum trisdiethylphosphinate. As the flame retardant, each of the exemplified flame retardants may be used alone or in combination of two or more.

[0105] As described above, the resin composition according to the present embodiment may contain an initiator (reaction initiator). The resin composition may proceed with the curing reaction even if it does not contain a reaction initiator. However, depending on the process conditions, it may be difficult to raise the temperature to a level where the curing proceeds, so a reaction initiator may be added. The reaction initiator is not particularly limited as long as it can promote the curing reaction between the modified polyphenylene ether compound and the curing agent. Specifically, examples of the reaction initiator include oxidizing agents such as α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, benzoyl peroxide, 3,3',5,5'-tetramethyl-1,4-diphenoquinone, chloranil, 2,4,6-tri-t-butylphenoxyl, t-butylperoxyisopropyl monocarbonate, and azobisisobutyronitrile. In addition, a carboxylate metal salt or the like may be used in combination as necessary. By doing so, the curing reaction can be further promoted. Among these, α,α'-bis(t-butylperoxy-m-isopropyl)benzene is preferably used. Since α,α'-bis(t-butylperoxy-m-isopropyl)benzene has a relatively high reaction initiation temperature, it can suppress the promotion of the curing reaction at the time when curing is not required, such as when drying the prepreg, and can suppress the deterioration of the storage stability of the polyphenylene ether resin composition. Furthermore, since α,α'-bis(t-butylperoxy-m-isopropyl)benzene has low volatility, it does not volatilize during drying or storage of the prepreg, and has good stability. Moreover, the reaction initiator may be used alone or in combination of two or more kinds.

[0106] As described above, the resin composition according to the present embodiment may contain a filler such as an inorganic filler. Examples of the filler include those added to enhance the heat resistance and flame retardancy of the cured product of the resin composition, and are not particularly limited. In addition, by including a filler, the heat resistance and flame retardancy can be further enhanced. Specific examples of the filler include silica such as spherical silica, metal oxides such as alumina, titanium oxide, and mica, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, talc, aluminum borate, barium sulfate, and calcium carbonate. Among these, silica, mica, and talc are preferable, and spherical silica is more preferable. In addition, the filler may be used alone or in combination of two or more. In addition, the filler may be used as it is, or may be surface-treated with the silane coupling agent. In addition, when a filler is included, its content (filler content) is preferably 30 to 270 mass% and more preferably 50 to 250 mass% relative to the resin composition.

[0107] (Manufacturing method) The method for producing the resin composition is not particularly limited, and examples thereof include a method of mixing the phosphorus-containing compound, the maleimide compound, the polyphenylene ether compound, and the curing agent to a predetermined content, etc. Specifically, in the case of obtaining a varnish-like composition containing an organic solvent, the method described below, etc. can be used.

[0108] Furthermore, by using the resin composition according to this embodiment, a prepreg, a metal-clad laminate, a wiring board, a metal foil with resin, and a film with resin can be obtained as follows.

[0109] [Prepreg] FIG. 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to an embodiment of the present invention.

[0110] 1, the prepreg 1 according to this embodiment includes the resin composition or a semi-cured product of the resin composition 2, and a fibrous base material 3. This prepreg 1 includes 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.

[0111] In this embodiment, the semi-cured product is a product in a state where the resin composition is partially cured to such an extent that the resin composition can be further cured. That is, the semi-cured product is a product in a semi-cured state (B-staged) of the resin composition. For example, when the resin composition is heated, the viscosity of the resin composition first gradually decreases, and then the resin composition starts to cure, and the viscosity gradually increases. In this case, the semi-cured state may be a state between when the viscosity starts to increase and when the resin composition is completely cured.

[0112] In addition, the prepreg obtained by using the resin composition according to the present embodiment may be a prepreg having a semi-cured product of the resin composition as described above, or may be a prepreg having the uncured resin composition itself. That is, it may be a prepreg having a semi-cured product of the resin composition (the resin composition in the B stage) and a fibrous base material, or a prepreg having the resin composition before curing (the resin composition in the A stage) and a fibrous base material. In addition, the resin composition or the semi-cured product of the resin composition may be a product obtained by drying or heating the resin composition.

[0113] When producing a prepreg, the resin composition 2 is often prepared in a varnish form and used to impregnate the fibrous base material 3, which is a 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.

[0114] First, each component that can be dissolved in an organic solvent is put into the organic solvent and dissolved. At this time, heating may be performed as necessary. Then, a component that is not dissolved in the organic solvent, which is used as necessary, is added, and dispersed until a predetermined dispersion state is reached using a ball mill, a bead mill, a planetary mixer, a roll mill, or the like, to prepare a varnish-like resin composition. The organic solvent used here is not particularly limited as long as it dissolves the maleimide compound, the polyphenylene ether compound, and the curing agent, and does not inhibit the curing reaction. Specific examples include toluene and methyl ethyl ketone (MEK).

[0115] The method for producing the prepreg is not particularly limited as long as the prepreg can be produced. Specifically, when producing the prepreg, the resin composition used in the present embodiment described above is often prepared in a varnish form and used as a resin varnish, as described above.

[0116] Specific examples of the fibrous substrate include glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. The use of glass cloth provides 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 yarn into a flat shape. The thickness of the fibrous substrate generally used is, for example, 0.01 mm or more and 0.3 mm or less.

[0117] The method for producing the prepreg is not particularly limited as long as the prepreg can be produced. Specifically, when producing the prepreg, the resin composition according to the present embodiment described above is often prepared in a varnish form and used as a resin varnish, as described above.

[0118] As a method for producing the prepreg 1, for example, a method of impregnating a fibrous substrate 3 with a resin composition 2, for example, a resin composition 2 prepared in a varnish form, and then drying the same can be mentioned. 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 addition, at this time, by repeating the impregnation using multiple resin compositions with different compositions and concentrations, it is also possible to adjust to the final desired composition and impregnation amount.

[0119] The fibrous substrate 3 impregnated with the resin composition (resin varnish) 2 is heated under desired heating 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 organic solvent can be volatilized from the resin varnish by the heating, thereby reducing or removing the organic solvent.

[0120] The resin composition according to the present embodiment is a resin composition having a high glass transition temperature, excellent flame retardancy, low water absorption, and excellent moldability, which can be used to obtain a cured product in which the increase in dielectric constant and dielectric tangent due to water absorption is sufficiently suppressed even after water absorption. Therefore, a prepreg including this resin composition or a semi-cured product of this resin composition is a prepreg having a high glass transition temperature, excellent flame retardancy, low water absorption, and excellent moldability, which can be used to obtain a cured product in which the increase in dielectric constant and dielectric tangent due to water absorption is sufficiently suppressed even after water absorption. This prepreg can be used to suitably manufacture a wiring board including an insulating layer having a high glass transition temperature, excellent flame retardancy, low water absorption, and sufficient suppression of the increase in dielectric constant and dielectric tangent due to water absorption even after water absorption.

[0121] [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.

[0122] As shown in FIG. 2, the metal-clad laminate 11 is composed of 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. That is, the metal-clad laminate 11 has an insulating layer 12 containing a cured product of a resin composition, and a metal foil 13 provided on the insulating layer 12. The 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. The thickness of the metal foil 13 varies depending on the performance required for 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, and when the metal foil is thin, it may be a carrier-attached copper foil having a release layer and a carrier to improve handling properties.

[0123] The method for producing the metal-clad laminate 11 is not particularly limited as long as the metal-clad laminate 11 can be produced. Specifically, a method for producing the metal-clad laminate 11 using a prepreg 1 can be mentioned. As this method, a method for producing a double-sided or single-sided metal-foil-clad laminate 11 can be mentioned, in which one or more prepregs 1 are stacked, and a metal foil 13 such as a copper foil is stacked on both sides or one side of the prepreg 1, and the metal foil 13 and the prepreg 1 are heated and pressurized to be laminated and integrated. That is, the metal-clad laminate 11 is obtained by stacking the metal foil 13 on the prepreg 1 and heating and pressurizing it. In addition, the heating and pressing conditions can be appropriately set depending on the thickness of the metal-clad laminate 11 to be produced and the type of composition of the prepreg 1. For example, the temperature can be 170 to 210°C, the pressure can be 3.5 to 4 MPa, and the time can be 60 to 150 minutes. In addition, the metal-clad laminate may be produced without using a prepreg. For example, a method may be mentioned 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.

[0124] The resin composition according to the present embodiment is a resin composition that has a high glass transition temperature, excellent flame retardancy, low water absorption, and even after water absorption, a cured product that sufficiently suppresses the increase in dielectric constant and dielectric loss tangent due to water absorption can be suitably obtained, and has excellent moldability. 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 suitably formed of a cured product that has a high glass transition temperature, excellent flame retardancy, low water absorption, and even after water absorption, the increase in dielectric constant and dielectric loss tangent due to water absorption is sufficiently suppressed. And, this metal-clad laminate can suitably manufacture a wiring board having an insulating layer that has a high glass transition temperature, excellent flame retardancy, low water absorption, and even after water absorption, the increase in dielectric constant and dielectric loss tangent due to water absorption is sufficiently suppressed.

[0125] [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.

[0126] As shown in Fig. 3, wiring board 21 according to this embodiment is 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. That is, wiring board 21 has insulating layer 12 containing a cured product of a resin composition, and wiring 14 provided on insulating layer 12. In addition, 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.

[0127] The method for producing the wiring board 21 is not particularly limited as long as the wiring board 21 can be produced. Specifically, a method for producing the wiring board 21 using the prepreg 1 can be mentioned. For example, the method includes a method for producing the wiring board 21 in which wiring is provided as a circuit on the surface of the insulating layer 12 by etching the metal foil 13 on the surface of the metal-clad laminate 11 produced as described above. That is, the wiring board 21 is 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, examples of the method for forming a circuit include circuit formation by a semi-additive process (SAP) or a modified semi-additive process (MSAP). The wiring board 21 has an insulating layer 12 that has a high glass transition temperature, excellent flame retardancy, low water absorption, and sufficiently suppresses increases in the dielectric constant and dielectric loss tangent due to water absorption even after water absorption.

[0128] Such a wiring board is a wiring board having an insulating layer suitably formed from a cured product that has a high glass transition temperature, excellent flame retardancy, low water absorption, and in which increases in dielectric constant and dielectric tangent due to water absorption are sufficiently suppressed even after water absorption.

[0129] [Metal foil with resin] FIG. 4 is a schematic cross-sectional view showing an example of a resin-coated metal foil 31 according to the present embodiment.

[0130] 4, the resin-coated metal foil 31 according to this embodiment includes a resin layer 32 containing the resin composition or a semi-cured product of the resin composition, and a metal foil 13. This resin-coated metal foil 31 has the metal foil 13 on the surface of the resin layer 32. That is, this resin-coated metal foil 31 includes the resin layer 32 and the metal foil 13 laminated together with the resin layer 32. The resin-coated metal foil 31 may also include another layer between the resin layer 32 and the metal foil 13.

[0131] The resin layer 32 may contain the semi-cured product of the resin composition as described above, or may contain the resin composition that has not been cured. That is, the resin-attached metal foil 31 may include a resin layer containing the semi-cured product of the resin composition (the resin composition in the B stage) and a metal foil, or may be a resin-attached metal foil that includes a resin layer containing the resin composition before curing (the resin composition in the A stage) and a metal foil. The resin layer may contain the resin composition or the 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 the resin composition that has been dried or heated and dried. The fibrous substrate may be the same as the fibrous substrate of the prepreg.

[0132] The metal foil may be any metal foil used in metal-clad laminates, including, for example, copper foil and aluminum foil.

[0133] The resin-coated metal foil 31 and the resin-coated film 41 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.

[0134] The method for producing the resin-coated metal foil 31 is not particularly limited as long as the resin-coated metal foil 31 can be produced. Examples of the method for producing the resin-coated metal foil 31 include a method of producing the resin-coated metal foil 31 by 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 by using a bar coater, for example. The applied resin composition is heated, for example, under conditions of 80° C. or higher and 180° C. or lower, and 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. The organic solvent can be volatilized from the resin varnish by the heating, thereby reducing or removing the organic solvent.

[0135] The resin composition according to the present embodiment is a resin composition that has a high glass transition temperature, excellent flame retardancy, low water absorption, and even after water absorption, can be used to obtain a cured product that sufficiently suppresses the increase in dielectric constant and dielectric loss tangent due to water absorption, and has excellent moldability. Therefore, a resin-attached metal foil having a resin layer containing this resin composition or a semi-cured product of this resin composition is a resin-attached metal foil having a resin layer that can be used to obtain a cured product that has a high glass transition temperature, excellent flame retardancy, low water absorption, and even after water absorption, can be used to suitably manufacture a wiring board that has an insulating layer that has a high glass transition temperature, excellent flame retardancy, low water absorption, and even after water absorption, can be used to suitably manufacture a wiring board that has an insulating layer that sufficiently suppresses the increase in dielectric constant and dielectric loss tangent due to water absorption. For example, a multilayer wiring board can be manufactured by stacking on a wiring board. The wiring board obtained by using such a resin-coated metal foil has an insulating layer that is suitably formed of a cured product that has a high glass transition temperature, excellent flame retardancy, low water absorption, and that sufficiently suppresses increases in dielectric constant and dielectric tangent due to water absorption even after water absorption.

[0136] [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.

[0137] 5, the resin-attached 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. This resin-attached film 41 includes the resin layer 42 and the support film 43 laminated together with the resin layer 42. The resin-attached film 41 may also include another layer between the resin layer 42 and the support film 43.

[0138] The resin layer 42 may contain the semi-cured product of the resin composition as described above, or may contain the resin composition that has not been cured. That is, the resin-attached film 41 may include a resin layer containing the semi-cured product of the resin composition (the resin composition in the B stage) and a support film, or may be a resin-attached film including a resin layer containing the resin composition before curing (the resin composition in the A stage) and a support film. The resin layer may contain the resin composition or the 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 the resin composition that has been dried or heated and dried. The fibrous substrate may be the same as the fibrous substrate of the prepreg.

[0139] Furthermore, any support film used for a resin-attached film can be used without any 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.

[0140] The resin-attached film 41 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 a polyolefin film, a polyester film, and a polymethylpentene film.

[0141] The support film and cover film may be subjected to surface treatment such as matte treatment, corona treatment, release treatment, and roughening treatment, if necessary.

[0142] The method for producing the resin-attached film 41 is not particularly limited as long as the resin-attached film 41 can be produced. Examples of the method for producing the resin-attached film 41 include a method in which the varnish-like resin composition (resin varnish) is applied onto the support film 43 and heated. The varnish-like resin composition is applied onto the support film 43 by using a bar coater, for example. The applied resin composition is heated under conditions of 80° C. or higher and 180° C. or lower, and 1 minute or longer and 10 minutes or shorter. The heated resin composition is formed on the support film 43 as an uncured resin layer 42. The organic solvent can be volatilized from the resin varnish by the heating, thereby reducing or removing the organic solvent.

[0143] The resin composition according to the present embodiment is a resin composition that has a high glass transition temperature, excellent flame retardancy, low water absorption, and even after water absorption, a cured product in which the increase in the dielectric constant and the dielectric loss tangent due to water absorption is sufficiently suppressed can be suitably obtained, and has excellent moldability. Therefore, a resin-attached film having a resin layer containing this resin composition or a semi-cured product of this resin composition is a resin-attached film having a resin layer from which a cured product in which the increase in the dielectric constant and the dielectric loss tangent due to water absorption is suitably obtained. This resin-attached film can be suitably used when manufacturing a wiring board having an insulating layer that has a high glass transition temperature, excellent flame retardancy, low water absorption, and even after water absorption, the increase in the dielectric constant and the dielectric loss tangent due to water absorption is sufficiently suppressed. For example, a multilayer wiring board can be manufactured by laminating the film on a wiring board and then peeling off the support film, or by laminating the film on a wiring board after peeling off the support film. A wiring board obtained using such a resin-attached film has an insulating layer that is suitably formed from a cured product that has a high glass transition temperature, excellent flame retardancy, low water absorption, and that sufficiently suppresses increases in dielectric constant and dielectric tangent due to water absorption even after water absorption.

[0144] As described above, this specification discloses various aspects of the technology, the main technologies of which are summarized below.

[0145] One aspect of the present invention is a resin composition containing a maleimide compound, a polyphenylene ether compound having an unsaturated double bond in the molecule, a phosphorus-containing compound having a group represented by the following formula (1) and a group containing a phosphorus atom in the molecule, and a curing agent.

[0146] [ka] In formula (1), R1 represents a hydrogen atom or an alkyl group.

[0147] According to such a configuration, a cured product can be suitably obtained which has a high glass transition temperature, excellent flame retardancy, low water absorption, and in which increases in dielectric constant and dielectric tangent due to water absorption are sufficiently suppressed even after water absorption, and a resin composition with excellent moldability can be provided.

[0148] This is believed to be due to the following:

[0149] First, it is believed that the resin composition is obtained by curing the polyphenylene ether compound together with the maleimide compound and the curing agent, and thus a cured product having a high glass transition temperature and maintaining the excellent low dielectric properties of polyphenylene ether can be obtained. In addition, it is believed that the resin composition can be suitably cured by containing the polyphenylene ether compound, the maleimide compound, and the curing agent, and thus a cured product having low water absorption and sufficiently suppressing the increase in dielectric constant and dielectric loss tangent due to water absorption even after water absorption can be obtained. In other words, it is believed that the resin composition is obtained by curing a cured product that can suitably maintain the excellent low dielectric properties of polyphenylene ether even after water absorption.

[0150] It is believed that the resin composition can improve its flame retardancy by containing the phosphorus-containing compound. Even if the compound contains phosphorus in the molecule other than the phosphorus-containing compound, there is a tendency that the flame retardancy can be improved. On the other hand, since the phosphorus-containing compound has not only a group containing a phosphorus atom but also a group represented by the formula (1) in the molecule, it is believed that the compound can be bonded to the polyphenylene ether compound or the like when the resin composition is cured. This makes it possible to effectively improve the flame retardancy of the cured product. In addition, in order to exhibit sufficient flame retardancy with a compound containing phosphorus in the molecule other than the phosphorus-containing compound, it is necessary to increase the content thereof, which tends to decrease the moldability of the resin composition. In this regard, the phosphorus-containing compound can increase the flame retardancy with a relatively small amount, so it is believed that the flame retardancy of the cured product can be sufficiently increased while suppressing the decrease in the moldability of the resin composition.

[0151] From the above, it is considered that the resin composition having the above-mentioned configuration can suitably give a cured product which has excellent moldability, a high glass transition temperature, excellent flame retardancy, low water absorption, and in which increases in dielectric constant and dielectric tangent due to water absorption are sufficiently suppressed even after water absorption.

[0152] In the resin composition, the group containing a phosphorus atom preferably contains a group represented by the following formula (2).

[0153] [ka]

[0154] According to such a configuration, a cured product having a high glass transition temperature, low water absorption, and even after water absorption, an increase in dielectric constant and dielectric tangent due to water absorption is sufficiently suppressed, and a cured product having excellent flame retardancy can be suitably obtained, and a resin composition having excellent moldability can be obtained.

[0155] In the resin composition, the curing agent preferably contains an allyl compound. The allyl compound preferably contains at least one of a triallyl isocyanurate compound and a diallyl bisphenol compound.

[0156] According to such a configuration, a cured product having excellent flame retardancy, low water absorption, and even after absorbing water, an increase in dielectric constant and dielectric tangent due to water absorption is sufficiently suppressed, and excellent heat resistance such as a high glass transition temperature can be suitably obtained, and a resin composition with excellent moldability can be obtained.

[0157] In addition, in the resin composition, it is preferable that the curing agent further contains at least one of a polyfunctional acrylate compound and a polyfunctional methacrylate compound. That is, it is preferable that the curing agent contains at least one of a polyfunctional acrylate compound and a polyfunctional methacrylate compound, and an allyl compound. It is also preferable that the polyfunctional methacrylate compound contains a dimethacrylate compound.

[0158] According to such a configuration, a cured product having a high glass transition temperature, excellent flame retardancy, low water absorption, and sufficient suppression of increases in dielectric constant and dielectric tangent due to water absorption even after water absorption, and further having excellent adhesion to metal foil and the like, can be suitably obtained, and a resin composition with excellent moldability can be obtained.

[0159] In the resin composition, the content of the phosphorus-containing compound is preferably 2 to 20 parts by mass with respect to 100 parts by mass of the total of the maleimide compound, the polyphenylene ether compound, and the curing agent.

[0160] According to such a configuration, a cured product having a high glass transition temperature, low water absorption, and even after water absorption, an increase in dielectric constant and dielectric tangent due to water absorption is sufficiently suppressed, and a cured product having excellent flame retardancy can be suitably obtained, and a resin composition having excellent moldability can be obtained.

[0161] In the resin composition, the content of the maleimide compound is preferably 10 to 75 parts by mass with respect to 100 parts by mass of the total of the maleimide compound, the polyphenylene ether compound, and the curing agent.

[0162] According to such a configuration, a cured product having a high glass transition temperature, low water absorption, and even after water absorption, an increase in dielectric constant and dielectric tangent due to water absorption is sufficiently suppressed, and a cured product having excellent flame retardancy can be suitably obtained, and a resin composition having excellent moldability can be obtained.

[0163] Another aspect of the present invention is a prepreg including the resin composition or a semi-cured product of the resin composition and a fibrous base material.

[0164] According to such a configuration, a cured product can be suitably obtained which has a high glass transition temperature, excellent flame retardancy, low water absorption, and in which increases in dielectric constant and dielectric tangent due to water absorption are sufficiently suppressed even after water absorption, making it possible to provide a prepreg with excellent moldability.

[0165] Another aspect of the present invention is a resin-attached film including a resin layer containing the resin composition or a semi-cured product of the resin composition, and a support film.

[0166] According to this configuration, it is possible to provide a resin-attached film having a resin layer which has a high glass transition temperature, excellent flame retardancy, low water absorption, and which can suitably give a cured product in which increases in dielectric constant and dielectric tangent due to water absorption are sufficiently suppressed even after water absorption.

[0167] Another aspect of the present invention is a resin-coated metal foil including a resin layer containing the resin composition or a semi-cured product of the resin composition, and a metal foil.

[0168] According to this configuration, it is possible to provide a resin-coated metal foil having a resin layer which has a high glass transition temperature, excellent flame retardancy, low water absorption, and which can suitably give a cured product in which increases in dielectric constant and dielectric tangent due to water absorption are sufficiently suppressed even after water absorption.

[0169] Another aspect of the present invention is a metal-clad laminate comprising an insulating layer containing a cured product of the resin composition or a cured product of the prepreg, and a metal foil.

[0170] According to this configuration, it is possible to provide a metal-clad laminate having an insulating layer that is suitably formed from a cured product that has a high glass transition temperature, excellent flame retardancy, low water absorption, and in which increases in dielectric constant and dielectric tangent due to water absorption are sufficiently suppressed even after water absorption.

[0171] Another aspect of the present invention is a wiring board including an insulating layer containing the cured product of the resin composition or the cured product of the prepreg, and wiring.

[0172] According to this configuration, it is possible to provide a wiring board having an insulating layer that is suitably formed from a cured product that has a high glass transition temperature, excellent flame retardancy, low water absorption, and in which increases in dielectric constant and dielectric tangent due to water absorption are sufficiently suppressed even after water absorption.

[0173] According to the present invention, a resin composition having a high glass transition temperature, excellent flame retardancy, low water absorption, and excellent moldability can be preferably obtained as a cured product in which increases in dielectric constant and dielectric loss tangent due to water absorption are sufficiently suppressed even after water absorption. Also, according to the present invention, a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board obtained using the resin composition are provided.

[0174] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples. EXAMPLES

[0175] [Examples 1 to 8 and Comparative Examples 1 to 5] In the present examples, each component used in preparing the resin composition will be described.

[0176] (Maleimide compounds) MIR-3000-70MT: Represented by the formula (3), in which R A , R B , R C , and R D A maleimide compound (MIR-3000-70MT, manufactured by Nippon Kayaku Co., Ltd.) in which the hydrogen atom is BMI2300: Polyphenylmethane maleimide (BMI2300 manufactured by Daiwa Chemical Industry Co., Ltd.) (Polyphenylene ether compounds: PPE) PPE-1: polyphenylene ether compound having a vinylbenzyl group (ethenylbenzyl group) at the end (OPE-2st 1200, Mn1200 manufactured by Mitsubishi Gas Chemical Company, Inc., a polyphenylene ether compound represented by the above formula (13), in which Z is a phenylene group, R2 to R4 are hydrogen atoms, and p is 1) PPE-2: a polyphenylene ether compound having a methacryloyl group at its terminal (a modified polyphenylene ether in which the terminal hydroxyl group of a polyphenylene ether is modified with a methacryloyl group, represented by the above formula (15), in which Y in formula (15) is a dimethylmethylene group (represented by formula (12), R34 and R 35 A modified polyphenylene ether compound in which the methyl group is used, SA9000 manufactured by SABIC Innovative Plastics, weight average molecular weight Mw2000, number of terminal functional groups 2 (Hardening agent: Allyl compound) TAIC: Triallyl isocyanurate (TAIC manufactured by Nippon Kasei Chemical Co., Ltd.) DABPA: 2,2'-diallyl bisphenol A (2,2'-diallyl-4,4'-isopropylidenediphenol, DABPA manufactured by Daiwa Chemical Industry Co., Ltd.) (Hardening agent: dimethacrylate compound) DCP: Tricyclodecane dimethanol dimethacrylate (NK Ester DCP manufactured by Shin-Nakamura Chemical Co., Ltd.) (Phosphorus-containing compounds and flame retardants) MC-4: (methacryloylmethyl)diphenylphosphine oxide (MC-4 manufactured by Katayama Chemical Industry Co., Ltd.: phosphorus-containing compound: a compound represented by the above formula (18), in which R1 in the above formula (18) is a methyl group) OP-935: Aluminum trisdiethylphosphinate (Exolit OP-935 manufactured by Clariant Japan Co., Ltd.: flame retardant other than the phosphorus-containing compounds (phosphinate compound): phosphorus concentration 23% by mass) PX-200: Aromatic condensed phosphate ester compound (PX-200 manufactured by Daihachi Chemical Industry Co., Ltd.: flame retardant other than the above phosphorus-containing compounds (phosphate ester compound): phosphorus concentration 9% by mass) (filling material) SC2500-SXJ: Silica particles surface-treated with a silane coupling agent that has a phenylamino group in the molecule (SC2500-SXJ manufactured by Admatechs Co., Ltd.)

[0177] (Preparation method) First, each component other than the filler was added to methyl ethyl ketone (MEK) and mixed to a solid content concentration of 70 mass% in the composition (parts by mass) shown in Table 1. The mixture was stirred for 60 minutes. Thereafter, the filler was added to the obtained liquid, and the filler was dispersed with a bead mill. In this way, a varnish-like resin composition (varnish) was obtained.

[0178] Next, an evaluation substrate (cured prepreg) was obtained as follows.

[0179] The obtained varnish was impregnated into a fibrous substrate (glass cloth: Asahi Kasei Corporation's #1080 type, E-glass), and then heated and dried at 130°C for about 3 to 8 minutes to produce a prepreg. At that time, the content (resin content) of the components that constitute the resin by the curing reaction relative to the prepreg was adjusted to about 70 mass%. Then, eight sheets of each of the obtained prepregs were stacked, heated to a temperature of 220°C at a heating rate of 4°C / min, and heated and pressurized at 220°C for 90 minutes under a pressure of 4 MPa to obtain an evaluation substrate (cured prepreg).

[0180] Next, an evaluation substrate (metal-clad laminate) was obtained as follows.

[0181] Two sheets of each prepreg were stacked, and copper foil (FV-WS, 18 μm thick, manufactured by Furukawa Electric Co., Ltd.) was placed on both sides of the stack. This was used as a pressure body, and heated and pressed at a temperature of 200°C and a pressure of 3 MPa for 2 hours to obtain an evaluation board (metal-clad laminate) with copper foil bonded to both sides.

[0182] The prepregs, evaluation substrates (cured prepregs), and evaluation substrates (metal-clad laminates) prepared as described above were evaluated by the methods described below.

[0183] [Glass transition temperature (Tg)] The Tg of the prepreg was measured using a viscoelasticity spectrometer "DMS6100" manufactured by Seiko Instruments Inc. Dynamic viscoelasticity measurement (DMA) was performed with a bending module at a frequency of 10 Hz, and the temperature at which tan δ was maximized when the temperature was raised from room temperature to 320°C at a heating rate of 5°C / min was defined as Tg. If Tg is higher than 320°C, it is indicated as ">320" in Table 1.

[0184] [Peel Strength] The copper foil was peeled off from the evaluation board (metal-clad laminate), and the peel strength at this time was measured in accordance with JIS C 6481. Specifically, the insulating layer (prepreg) on ​​the top surface of the evaluation board was peeled off at a speed of 50 mm / min using a tensile tester, and the peel strength at this time (N / mm) was measured.

[0185] [Water absorption rate] The water absorption rate (%) of the evaluation substrate (cured prepreg) was measured by a method in accordance with IPC-TM-650 2.6.2.1.

[0186] [Dielectric properties (dielectric constant and dielectric tangent)] The dielectric constant and dielectric loss tangent of the evaluation board (cured prepreg) at 1 GHz were measured in accordance with IPC-TM650-2.5.5.9. Specifically, an impedance analyzer (RF impedance analyzer HP4291B manufactured by Agilent Technologies) was used to measure the dielectric constant and dielectric loss tangent of the evaluation board at 1 GHz. The dielectric constant and dielectric loss tangent were measured both before and after the evaluation board was allowed to absorb water.

[0187] In addition, the difference between the relative dielectric constant after water absorption and the relative dielectric constant before water absorption, and the difference between the dielectric tangent after water absorption and the dielectric tangent before water absorption were calculated.

[0188] [Moldability] A 100 mm x 100 mm prepreg with a rectangular (30 mm x 30 mm) hole formed in the center was prepared. This prepreg was sandwiched between plates using triacetyl cellulose (TAC) film as a release film. That is, the prepreg was sandwiched between TAC films, and the prepreg sandwiched between the TAC films was sandwiched between plates. The prepreg sandwiched between the plates was heated and pressed for 15 minutes under a pressure of 1380 ± 70 kPa using a lamination molding press set at 171 ± 2.6 ° C. Thereafter, it was cooled to room temperature, and the heated and pressed prepreg was visually observed.

[0189] As a result, the area of ​​the holes in the prepreg that were heated and pressurized due to the holes formed in the prepreg before the heating and pressurization, i.e., the area of ​​the holes remaining after the prepreg in which the holes were formed, was 20 mm 2 If the area of ​​the hole in the prepreg heated is less than 20 mm2, it is evaluated as "○". 2 If it was more than this, it was rated as "X".

[0190] [Flame retardant] A test piece measuring 125 mm in length and 12.5 mm in width was cut out from the evaluation board (cured prepreg). Then, a combustion test was conducted on this test piece in accordance with Underwriters Laboratories' "Test for Flammability of Plastic Materials-UL 94" to evaluate its flammability. If the flammability was at the "V-0" level, it was indicated as "V-0" in Table 1, and if it was at the "V-1" level, it was indicated as "V-1".

[0191] The results of each of the above evaluations are shown in Table 1. Note that the "P content (% by mass) in the resin composition (excluding the filler)" indicates the ratio (% by mass) of the mass of phosphorus atoms (P) contained in the resin composition to the mass of the resin composition excluding the filler.

[0192] [Table 1]

[0193] As can be seen from Table 1, in the resin compositions containing the maleimide compound, the polyphenylene ether compound, and the curing agent, the resin compositions further containing a phosphorus-containing compound having in its molecule a group represented by the formula (1) and a group containing a phosphorus atom (Examples 1 to 8) had excellent flame retardancy and moldability, as compared with the resin compositions containing a flame retardant other than the phosphorus-containing compound (Comparative Examples 1 to 3).

[0194] When the resin compositions according to Examples 1 to 8 were used, Tg was as high as 250° C. or more, and was higher than when a resin composition not containing the maleimide compound was used (Comparative Example 4).

[0195] When the resin compositions according to Examples 1 to 8 were used, the water absorption rate was low at 0.6% or less, and was lower than that when a resin composition not containing the polyphenylene ether compound was used (Comparative Example 5). Furthermore, when the resin compositions according to Examples 1 to 8 were used, the relative dielectric constant and dielectric loss tangent were low even after water absorption, and the increase in the relative dielectric constant and dielectric loss tangent due to water absorption was small. For example, when the resin compositions according to Examples 1 to 8 were used, the change in the dielectric loss tangent due to water absorption was low at 0.0040 or less, and was lower than that when a resin composition not containing the polyphenylene ether compound was used (Comparative Example 5).

[0196] From the above, it has been found that by further containing a phosphorus-containing compound having in its molecule a group represented by formula (1) and a group containing a phosphorus atom in a resin composition containing the maleimide compound, the polyphenylene ether compound, and the curing agent, a cured product having a high glass transition temperature, excellent flame retardancy, low water absorption, and in which increases in dielectric constant and dielectric tangent due to water absorption are sufficiently suppressed even after water absorption can be suitably obtained, and a resin composition with excellent moldability can be obtained.

[0197] This application is based on Japanese Patent Application No. 2019-120081, filed on June 27, 2019, the contents of which are incorporated herein by reference.

[0198] In order to express the present invention, the present invention has been described adequately and sufficiently through the embodiments in the above description, but it should be recognized that those skilled in the art can easily modify and / or improve the above-mentioned embodiments. Therefore, unless the modification or improvement made by those skilled in the art is at a level that departs from the scope of the claims described in the claims, the modification or improvement is interpreted as being included in the scope of the claims. [Industrial Applicability]

[0199] According to the present invention, there is provided a resin composition which can suitably obtain a cured product having a high glass transition temperature, excellent flame retardancy, low water absorption, and which can sufficiently suppress increases in dielectric constant and dielectric loss tangent due to water absorption even after water absorption, and which has excellent moldability. Also, 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.

Claims

1. A maleimide compound represented by the following formula (3), A polyphenylene ether compound having an unsaturated double bond in the molecule, A phosphorus-containing compound having a group represented by the following formula (1) and a group containing a phosphorus atom in the molecule, A hardener is included, the content of the maleimide compound is 10 to 75 parts by mass with respect to 100 parts by mass in total of the maleimide compound, the polyphenylene ether compound, and the curing agent, The content of the phosphorus-containing compound is 2 to 15 parts by mass per 100 parts by mass of the total of the maleimide compound, the polyphenylene ether compound, and the curing agent. 【Chemistry 1】 [In formula (1), R １ represents a hydrogen atom or an alkyl group. 【Chemistry 2】 [In formula (3), s represents 1 to 5; 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.

2. The resin composition according to claim 1 , wherein the group containing a phosphorus atom contains a group represented by the following formula (2): 【Chemistry 3】

3. The resin composition according to claim 1 or 2, wherein the curing agent comprises an allyl compound.

4. The resin composition according to claim 3 , wherein the allyl compound comprises at least one of a triallyl isocyanurate compound and a diallyl bisphenol compound.

5. The resin composition according to claim 3 or 4, wherein the curing agent further comprises at least one of a polyfunctional acrylate compound and a polyfunctional methacrylate compound.

6. The resin composition according to claim 5 , wherein the polyfunctional methacrylate compound includes a dimethacrylate compound.

7. A prepreg comprising the resin composition according to any one of claims 1 to 6 or a semi-cured product of the resin composition and a fibrous base material.

8. A resin-attached film comprising a resin layer containing the resin composition according to any one of claims 1 to 6 or a semi-cured product of the resin composition, and a support film.

9. A resin-coated metal foil comprising a resin layer containing the resin composition according to any one of claims 1 to 6 or a semi-cured product of the resin composition, and a metal foil.

10. A metal-clad laminate comprising an insulating layer comprising a cured product of the resin composition according to any one of claims 1 to 6 or a cured product of the prepreg according to claim 7, and a metal foil.

11. A wiring board comprising an insulating layer comprising a cured product of the resin composition according to any one of claims 1 to 6 or a cured product of the prepreg according to claim 7, and wiring.

Images