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

Abstract

One aspect of the present invention is a resin composition comprising: a polymaleimide resin (A) having a partial structure represented by general formula (1), a partial structure represented by general formula (T-1) and chemically bonded to the partial structure represented by general formula (1), and a partial structure represented by general formula (T-2) and chemically bonded to the partial structure represented by general formula (1); and a benzoxazine compound (B).

Description

Resin compositions, prepregs, resin-coated films, resin-coated metal foils, metal-clad laminates, and wiring boards

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

[0002] In various electronic devices, with the increasing amount of information to be processed and the speed of information communication to be increased, there is a need to increase the signal transmission speed and reduce signal loss during signal transmission. For this reason, resin compositions that yield cured products with low relative permittivity and dielectric loss tangent are used as substrate materials for the insulating layer in the wiring boards used in these electronic devices. Examples of such resin compositions include the curable composition described in Patent Document 1.

[0003] Patent Document 1 describes a curable composition containing a polymaleimide resin having a predetermined substructure having a benzene ring in a main chain linked by methylene groups, and a predetermined substructure having a maleimide group and a benzene ring bonded to the aforementioned substructure. According to Patent Document 1, it is disclosed that by including the polymaleimide resin, a cured product can be obtained that has high solubility in solvents and exhibits low dielectric loss tangent and high heat resistance during curing.

[0004] The substrate material used to form the insulating layer of a wiring board is also required to have a high glass transition temperature and to produce a cured product with low thermal expansion coefficient and water absorption rate.

[0005] Japanese Patent Publication No. 2024-4392

[0006] The present invention has been made in view of the above circumstances, and aims to provide a resin composition that yields a cured product with a high glass transition temperature and low thermal expansion coefficient and water absorption rate. The present invention also aims to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that can be obtained using the above resin composition.

[0007] One aspect of the present invention is a resin composition comprising: a polymaleimide resin (A) having a partial structure represented by the following general formula (1), a partial structure represented by general formula (T-1) chemically bonded to the partial structure represented by general formula (1), and a partial structure represented by general formula (T-2) chemically bonded to the partial structure represented by general formula (1); and a benzoxazine compound (B).

[0008]

[0009] In the above general formula (1), R １３ each independently represent an alkyl group having 1 to 18 carbon atoms, m ２ represents an integer of 0 or more and 4 or less, n １ represents an average number of repeating units, two * each represent a bond, one of the bonds is chemically bonded at the position of L １３ or L １４ in the following general formula (T-1), and the other bond is chemically bonded at the position of L １１ or L １２ in the following general formula (T-2).

[0010]

[0011] In the above general formula (T-1) or (T-2), R １１ and R １５ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, R １２ and R １４ each independently represent a hydrocarbon group having 1 to 18 carbon atoms, L １１ to L １４ each independently represent a bond or a hydrogen atom, provided that the partial structure represented by general formula (1) is chemically bonded at the position of L １１ or L １２ , and the partial structure represented by general formula (1) is chemically bonded at the position of L １３ or L １４ , and L that are not chemically bonded to the partial structure represented by general formula (1) １１ to L １４ are hydrogen atoms, and m １ and m ３ each represent 2.

[0012] The above-mentioned and other objectives, features, and advantages of the present invention will become apparent from the following detailed description and accompanying drawings.

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

[0014] In electronic devices, with the increasing demand for higher performance and significantly faster information and communication speeds, there is a growing need for higher performance and greater integration in printed circuit boards used in applications such as network equipment, servers, and AI (artificial intelligence) processors. As a result, printed circuit boards are becoming denser, thinner, and larger.

[0015] As printed circuit boards (PCBs) become thinner and larger, the semiconductor package substrates on which semiconductor chips are mounted are more prone to warping. This warping can cause mounting defects, and this effect is particularly pronounced when using high-density PCBs. Therefore, to ensure high connection reliability that does not cause mounting defects even when using high-density PCBs, it is necessary to suppress the occurrence of warping in the PCBs. Accordingly, in order to obtain PCBs in which warping is suppressed, it is necessary to obtain a cured product with a low coefficient of thermal expansion for the substrate material that constitutes the insulating layer of the PCB.

[0016] Printed circuit boards used in various electronic devices are required to be less susceptible to changes in the external environment. For example, to ensure that printed circuit boards can be used with stable physical properties even in relatively high humidity environments, the substrate material used to form the insulating layer of the printed circuit board must yield a cured product with low water absorption. It is believed that the insulating layer of a printed circuit board obtained from such a substrate material with low water absorption can suppress moisture absorption, allowing the printed circuit board to be used even in relatively high humidity environments. Furthermore, during the manufacturing of printed circuit boards, positional accuracy during substrate processing is crucial for circuit formation and drill-through hole processing, so high dimensional stability is required for the substrate material. If the substrate material has high water absorption, the insulating layer of the printed circuit board is likely to absorb moisture and become easily deformed. This effect is particularly pronounced when using high-density printed circuit boards, where fine circuit formation and closely spaced drill-through hole processing are important. Therefore, in order to enable the use of printed circuit boards even in relatively high humidity environments, and to stably manufacture high-density printed circuit boards, it is required that the substrate material yield a cured product with low water absorption. Furthermore, when manufacturing semiconductor packages using high-density wiring boards, the semiconductor chips are exposed to high temperatures such as those in reflow ovens during mounting. Therefore, the substrate material for the insulating layer of the wiring board is required to have excellent heat resistance, such as a high glass transition temperature, resulting in a cured product. In addition, when manufacturing semiconductor packages, it is required that physical properties such as elastic modulus do not change at high temperatures. A high glass transition temperature of the insulating layer suppresses changes in elastic modulus due to temperature changes, thereby improving insulation reliability. For this reason, a high glass transition temperature is required for the substrate material for the insulating layer of the wiring board.

[0017] To obtain a resin composition that yields a cured product with high heat resistance as a substrate material, the use of maleimide compounds, such as the polymaleimide resin described in Patent Document 1, has been considered. However, according to the inventors' research, simply including the polymaleimide resin in the resin composition sometimes resulted in a cured product with a glass transition temperature that was not sufficiently high, a cured product with a thermal expansion coefficient that was not sufficiently low, or a cured product with a water absorption rate that was not sufficiently low. Therefore, the inventors have found that the components included together with the polymaleimide resin affect the glass transition temperature, thermal expansion coefficient, and water absorption rate of the resulting cured product.

[0018] As a result of various studies, the inventors have found that the above objective, which is to provide a resin composition that yields a cured product with a high glass transition temperature and low thermal expansion coefficient and water absorption rate, can be achieved by the present invention as described below.

[0019] The embodiments of the present invention will be described below, but the present invention is not limited thereto.

[0020] [Resin Composition] The resin composition according to the embodiment of the present invention is a resin composition comprising the following polymaleimide resin (A) and benzoxazine compound (B). By curing the resin composition, a cured product is obtained that has a high glass transition temperature and low thermal expansion coefficient and water absorption rate.

[0021] (Polymaleimide resin (A)) Polymaleimide resin (A) is a polymaleimide resin having a substructure represented by the following general formula (1), a substructure represented by general formula (T-1) that is chemically bonded to the substructure represented by general formula (1), and a substructure represented by general formula (T-2) that is chemically bonded to the substructure represented by general formula (1).

[0022]

[0023] In the above general formula (1), R １３ Each of these independently represents an alkyl group having 1 to 18 carbon atoms, m ２ represents an integer between 0 and 4, and n １represents the average number of repeating units, the two *s each represent a bond, and one of the bond is L in the general formula (T-1) below. １３ or L １４ A chemical bond is formed at the position, and the other bond is L in the general formula (T-2) below. １１ or L １２ This indicates that a chemical bond is formed at that position.

[0024]

[0025] In the above general formula (T-1) or (T-2), R １１ and R １５ Each of these independently represents a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, R １２ and R １４ Each of these independently represents a hydrocarbon group with 1 to 18 carbon atoms, L １１ ~L １４ Each of these independently represents a bonding bond or a hydrogen atom, however, L １１ or L １２ At the position, it is chemically bonded to the substructure represented by general formula (1), and L １３ or L １４ At this position, L is chemically bonded to the substructure represented by general formula (1), and L is not chemically bonded to the substructure represented by general formula (1). １１ ~L １４ is a hydrogen atom, m １ and m ３ Each of these represents 2.

[0026] Polymaleimide resin (A) exhibits high solubility in solvents and low dielectric loss tangent and high heat resistance during curing. Because the chemical structure of polymaleimide resin (A) has only one bonding site each at the ortho and para positions of the benzene ring to which the maleimide group is attached, a linearly chain-extended polymaleimide resin can be obtained, making molecular weight control easy and enabling a balance between heat resistance, low dielectric properties, and solvent solubility.

[0027] In the general formula (1) above, the two *s each represent a bonding hand. And one of the two bonding hands is L in the general formula (T-1) above. １３ or L １４A chemical bond is formed at the position. The other bond is L in the general formula (T-2) above. １１ or L １２ Chemical bonding occurs at the position. Therefore, the polymaleimide resin (A) has a structural unit in which a substructure represented by general formula (T-1) and a substructure represented by general formula (T-2) are linked by a substructure represented by general formula (1), and the substructure represented by general formula (1) is chemically bonded to the maleimide group on the benzene ring in general formula (T-1) and general formula (T-2) at the para position or one ortho position.

[0028] In addition, in the above general formula (1), n １ If the number is 2 or more, there are multiple R １３ They may be the same or different from each other. ２ If the number is 2 or more, there are multiple R １３ They may be the same as or different from each other.

[0029] In the above general formula (1), R １３ Each of these independently represents a hydrocarbon group having 1 to 18 carbon atoms, preferably a hydrocarbon group having 1 to 12 carbon atoms, and more preferably a hydrocarbon group having 1 to 6 carbon atoms. ２ If R is an integer greater than or equal to 2, there are multiple R's. １３ These may be the same or different from each other. Preferred R in general formula (1) １３ The alkyl group is preferably a linear alkyl group, and more preferably a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, tert-pentyl group, or neopentyl group.

[0030] In this specification, the "reaction raw materials" described later refer to precursors for obtaining the target polymaleimide resin or its precursor compound (e.g., an intermediate amine compound (γ) in which aromatic amine compounds (α) are linked via structural units derived from a compound (β) having a benzyl ether skeleton) by a chemical reaction. １３The bonded benzene ring may be the benzene ring of a compound (β) having a benzyl ether skeleton, as described later.

[0031] In the above general formula (1), m ２ R represents an integer between 0 and 4, preferably an integer less than or equal to 2, and more preferably 2. Note that R in general formula (1) １３ In a benzene ring to which R is bonded, if the 1st and 3rd positions are bonded by a methylene group, then the 4th and 6th positions are R １３ It is preferable that they are each connected.

[0032] In the above general formula (1), n １ This represents the average number of repeating units, and from the viewpoint of the viscosity of the resulting polymaleimide resin, it is preferably 0 to 50, preferably 0 to 30, and preferably 0 to 15. This average number of repeating units can be calculated from the charge ratio or NMR, etc.

[0033] The polymaleimide resin (A) preferably contains 1 to 99% by mass of the substructure represented by general formula (1) based on the total amount (100% by mass) of the polymaleimide resin (A), more preferably 3 to 97% by mass, and even more preferably 5 to 95% by mass.

[0034] In the above general formula (T-1), R １５ Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, preferably a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, more preferably a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. Particularly preferred R １５ These can be hydrogen atoms or linear alkyl groups having 1 to 6 carbon atoms. ３ Since is 2, the two R １５ They may be the same as or different from each other.

[0035] In the above general formula (T-1), R １４ Each of these independently represents a hydrocarbon group having 1 to 18 carbon atoms, preferably a hydrocarbon group having 1 to 12 carbon atoms, and more preferably a hydrocarbon group having 1 to 6 carbon atoms. Particularly preferred R １４These can be linear alkyl groups having 1 to 6 carbon atoms.

[0036] By allowing a bonding site with the substructure represented by general formula (1) at the ortho position (position 6) of the benzene ring of the above general formula (T-1) or the above general formula (T-2), higher solubility in solvents is achieved, and superior low dielectric loss tangent and high heat resistance are exhibited during curing. Note that R in general formula (T-1) １４ The benzene ring to which it is bonded may be the benzene ring of the aromatic amine compound (α) described later.

[0037] In the above general formula (T-1), L １３ or L １４ Each of these independently represents a bond or a hydrogen atom. However, L １３ or L １４ At least one of the positions of the substructure is chemically bonded to the substructure represented by general formula (1) and the substructure represented by general formula (T-1). In addition, L does not chemically bond to the substructure represented by general formula (1). １３ or L １４ L is a hydrogen atom. １３ or L １４ A substructure represented by general formula (1) may be chemically bonded to each of the two locations.

[0038] In the above general formula (T-2), R １１ Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, preferably a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, more preferably a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. Preferred R １１ These can be hydrogen atoms or linear alkyl groups having 1 to 6 carbon atoms. １ Since is 2, two R １１ They may be the same as or different from each other.

[0039] In the above general formula (T-2), R １２ Each of these independently represents a hydrocarbon group having 1 to 18 carbon atoms, preferably a hydrocarbon group having 1 to 12 carbon atoms, and more preferably a hydrocarbon group having 1 to 6 carbon atoms. Preferred R １２In this context, it represents a linear alkyl group with 1 to 6 carbon atoms.

[0040] Note that R in the general formula (T-2) １２ The benzene ring to which it is bonded can be the benzene ring of the aromatic amine compound (α).

[0041] In the above general formula (T-2), L １１ or L １２ Each of these independently represents a bond or a hydrogen atom. However, L １１ or L １２ At least one of the positions of the substructure is chemically bonded to the substructure represented by general formula (1) and the substructure represented by general formula (T-2). In addition, L does not chemically bond to the substructure represented by general formula (1). １１ or L １２ L is a hydrogen atom. １１ and L １２ A substructure represented by general formula (1) may be chemically bonded to each of the two locations.

[0042] The polymaleimide resin (A) preferably contains 1 to 99% by mass of the substructure represented by general formula (T-1) based on the total amount (100% by mass) of the polymaleimide resin (A), more preferably 3 to 97% by mass, and even more preferably 5 to 95% by mass.

[0043] The polymaleimide resin (A) preferably contains 1 to 99% by mass of the substructure represented by general formula (T-1) based on the total amount (100% by mass) of the polymaleimide resin (A), more preferably 3 to 97% by mass, and even more preferably 5 to 95% by mass.

[0044] <Physical Properties of Polymaleimide Resin (A)> The number-average molecular weight (Mn) of polymaleimide resin (A) is preferably in the range of 200 to 1500, and more preferably in the range of 300 to 800. The weight-average molecular weight (Mw) of polymaleimide resin (A) is preferably in the range of 280 to 2000, and more preferably in the range of 330 to 1200.

[0045] The polymaleimide resin (A) is excellent in solvent solubility, heat resistance and low dielectric loss tangent, and therefore preferably has a molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) calculated from gel permeation chromatography (GPC) measurement in the range of 1.01 to 4.0, more preferably 1.05 to 2.0, and still more preferably 1.10 to 1.8.

[0046] The number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the polymaleimide resin (A) are measured using gel permeation chromatography (hereinafter abbreviated as "GPC").

[0047] <Method for Producing Polymaleimide Resin (A)> Hereinafter, a method for producing the polymaleimide resin (A) will be described.

[0048] The production method of the polymaleimide resin (A) is not particularly limited, and the polymaleimide resin (A) may be produced by any method as long as it has the partial structure represented by the above general formula (1), the partial structure represented by the above general formula (T-1) chemically bonded to the partial structure represented by the above general formula (1), and the partial structure represented by the above general formula (T-2) chemically bonded to the partial structure represented by the above general formula (1). As a preferred embodiment of the method for producing a polymaleimide resin according to the present embodiment, it is preferable to use an aromatic amine compound (α) represented by the following general formula (a-1), a compound (β) having a benzyl ether skeleton, and maleic anhydride as reaction raw materials.

[0049]

[0050] In the above general formula (a-1), R ａ１ and R ａ２ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R １ represents a hydrocarbon group having 1 to 18 carbon atoms, and R ２ and R ３ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms.

[0051] (Benzoxazine compound (B)) The benzoxazine compound (B) is not particularly limited as long as it is a compound having a benzoxazine group in the molecule. The benzoxazine compound (B) may be a benzoxazine resin as long as it has a benzoxazine group in the molecule. Examples of the benzoxazine compound (B) include a benzoxazine compound (B1) having an allyl group in the molecule. The benzoxazine compound (B1) has not only the allyl group but also a benzoxazine group in the molecule. Examples of the benzoxazine group include a benzoxazine group represented by the following formula (2), a benzoxazine group represented by the following formula (3), and the like. Further, examples of the benzoxazine compound (B1) include a benzoxazine compound (B1-1) having a benzoxazine group represented by the following formula (2) in the molecule, a benzoxazine compound (B1-2) having a benzoxazine group represented by the following formula (3) in the molecule, and a benzoxazine compound (B1-3) having both a benzoxazine group represented by the following formula (2) and a benzoxazine group represented by the following formula (3) in the molecule.

[0052]

[0053] In formula (2), R ４ represents an allyl group, and p represents 1 to 4. p is an average value of the degree of substitution of R ４ , which is 1 to 4, and preferably 1.

[0054]

[0055] In formula (3), R ５ represents an allyl group.

[0056] Specific examples of the benzoxazine compound (B) include, as the benzoxazine compound (B1-1), a benzoxazine compound (B1-4) represented by the following formula (4), and it is preferable that the benzoxazine compound (B) contains this benzoxazine compound (B1-4).

[0057]

[0058] In formula (4), R ６ and R ７represents an allyl group, X represents an ether bond (-O-) or an alkylene group, and q and r independently represent 1 to 4.

[0059] The alkylene group is not particularly limited and includes, for example, a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octane group, an eicosane group, and a hexatriacontane group. Among these, the methylene group is preferred.

[0060] q is R ６ The average value of the degree of substitution is 1 to 4, and preferably 1. Also, r is R ７ The average value of the degree of substitution is between 1 and 4, and preferably 1.

[0061] As the benzoxazine compound (B), a commercially available product may be used, for example, ALP-d manufactured by Shikoku Chemicals, Inc.

[0062] As the benzoxazine compound (B), the benzoxazine compounds exemplified above may be used individually or in combination of two or more. For example, as the benzoxazine compound (B), each of the following may be used individually: benzoxazine compound (B1-1) having a benzoxazine group represented by formula (2) in its molecule, benzoxazine compound (B1-2) having a benzoxazine group represented by formula (3) in its molecule, and benzoxazine compound (B1-3) having a benzoxazine group represented by formula (2) and a benzoxazine group represented by formula (3) in its molecule, or two or more of these may be used in combination.

[0063] (Maleimide Compound (C)) The resin composition according to this embodiment may further contain a maleimide compound (C) different from the polymaleimide resin (A), to the extent that it does not impair the effects of the present invention. Maleimide compound (C) is a maleimide compound having a maleimide group in its molecule and different from the polymaleimide resin (A). By further including maleimide compound (C), a resin composition can be obtained in which a cured product with a higher glass transition temperature and a lower coefficient of thermal expansion is obtained. From this point of view, it is preferable that the resin composition further contains maleimide compound (C). In the resin composition according to this embodiment, it is preferable that the maleimide compound (C) is a maleimide compound different from the polymaleimide resin (A) with a maleimide equivalent of 500 g / mol or less. The functional group equivalent (maleimide equivalent) of the maleimide group of maleimide compound (C) is preferably 500 g / mol or less, more preferably 450 g / mol or less, and even more preferably 300 g / mol or less. Examples of maleimide compounds (C) include monofunctional maleimide compounds having one maleimide group in the molecule, polyfunctional maleimide compounds having two or more maleimide groups in the molecule, and modified maleimide compounds. Examples of the modified maleimide compounds include modified maleimide compounds in which part of the molecule is modified with an amine compound, modified maleimide compounds in which part of the molecule is modified with a silicone compound, and modified maleimide compounds in which part of the molecule is modified with both an amine compound and a silicone compound.

[0064] Examples of maleimide compounds (C) include maleimide compounds having at least one of an indane structure and an arylene structure bonded in a meta orientation within the molecule. More specifically, examples of maleimide compounds (C) include maleimide compounds having an indane structure within the molecule (C1), maleimide compounds having an arylene structure bonded in a meta orientation within the molecule (C2), maleimide compounds having an indane structure and an arylene structure bonded in a meta orientation within the molecule (C3), and maleimide compounds having neither the indane structure nor the arylene structure bonded in a meta orientation within the molecule (C4).

[0065] Maleimide compound (C1) Maleimide compound (C1) is not particularly limited as long as it is a maleimide compound having an indane structure in its molecule. Note that maleimide compound (C1) has not only the indane structure but also a maleimide group in its molecule. The indane structure is, for example, the indane structure represented by the following formula (5). Specifically, maleimide compound (C1) is a maleimide compound (C1-1) having the structure represented by the following formula (5) in its molecule as the indane structure, and more specifically, a maleimide compound (C1-1-1) represented by the following formula (6) is an example.

[0066]

[0067] In formula (5), each Rb is independent. That is, each Rb may be the same group or different groups. For example, when a is 2 or 3, the two or three Rb groups bonded to the same benzene ring may be the same group or different groups. Rb represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group (alkoxy group) having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group (thiol group). a represents 0 to 3.

[0068]

[0069] In formula (6), each Ra is independent. That is, each Ra may be the same group or a different group. For example, when b is 2 to 4, the 2 to 4 Ra groups bonded to the same benzene ring may be the same group or a different group. Ra represents a C1 to C10 alkyl group, a C1 to C10 alkyloxy group, a C1 to C10 alkylthio group, a C6 to C10 aryl group, a C6 to C10 aryloxy group, a C6 to C10 arylthio group, a C3 to C10 cycloalkyl group, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. Rb is the same as Rb in formula (5), and each independently represents a C1-C10 alkyl group, a C1-C10 alkyloxy group, a C1-C10 alkylthio group, a C6-C10 aryl group, a C6-C10 aryloxy group, a C6-C10 arylthio group, a C3-C10 cycloalkyl group, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. b represents 0-4. a represents 0-3. n represents 0.95-10.

[0070] a is the average degree of substitution of Rb, and a smaller value is preferable, specifically a value of 0. That is, in the benzene ring to which Rb can be bonded, it is preferable that a hydrogen atom is bonded at the position where Rb can be bonded. Maleimide compounds (C1) with a such a value are easy to synthesize. This is thought to be due to reduced steric hindrance and increased electron density of the aromatic ring. Furthermore, when a is 1 to 3, Rb is preferably at least one selected from the group consisting of C1-C4 alkyl groups, C3-C6 cycloalkyl groups, and C6-C10 aryl groups. Furthermore, Ra is preferably at least one selected from the group consisting of C1-C4 alkyl groups, C3-C6 cycloalkyl groups, and C6-C10 aryl groups. By using C1-C4 alkyl groups, C3-C6 cycloalkyl groups, and C6-C10 aryl groups, the compound becomes more soluble in solvents, and the decrease in the reactivity of the maleimide group can be suppressed, resulting in a suitable cured product. This is thought to be due to a decrease in planarity and crystallinity near the maleimide group.

[0071] The groups represented by Ra and Rb specifically include the following groups:

[0072] The C1-C10 alkyl group is not particularly limited, and examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0073] The alkyloxy group having 1 to 10 carbon atoms is not particularly limited, and examples include a methyloxy group, an ethyloxy group, a propyloxy group, a hexyloxy group, and a decyloxy group.

[0074] The alkylthio group having 1 to 10 carbon atoms is not particularly limited, and examples include a methylthio group, an ethylthio group, a propylthio group, a hexylthio group, and a decylthio group.

[0075] The aryl group having 6 to 10 carbon atoms is not particularly limited, and examples include a phenyl group and a naphthyl group.

[0076] The aryloxy group having 6 to 10 carbon atoms is not particularly limited, and examples include a phenyloxy group and a naphthyloxy group.

[0077] The arylthio group having 6 to 10 carbon atoms is not particularly limited, and examples include a phenylthio group and a naphthylthio group.

[0078] The cycloalkyl group having 3 to 10 carbon atoms is not particularly limited, and examples include a cyclopropyl group, a cyclobutyl group, a cyclohexyl group, and a cyclooctyl group.

[0079] Examples of the halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0080] b is the average degree of substitution of Ra, preferably 2 to 3, and more preferably 2. The maleimide compound (C1) with such a b is easy to synthesize. This is thought to be because, especially when b is 2, the steric hindrance decreases and the electron density of the aromatic ring increases.

[0081] n is the average value of the number of repetitions, and as described above, it is 0.95 to 10, preferably 0.98 to 8, more preferably 1 to 7, and even more preferably 1.1 to 6. The maleimide compound (C1-1) having the indane structure represented by formula (5) in its molecule and the maleimide compound (C1-1-1) represented by formula (6) preferably contains the maleimide compound in which the average value of the number of repetitions (degree of polymerization), n, is 0, and is 32% by mass or less of the total amount of the maleimide compound (C1).

[0082] The maleimide compound (C1) preferably has a molecular weight distribution (Mw / Mn) of 1 to 4, more preferably 1.1 to 3.8, even more preferably 1.2 to 3.6, and particularly preferably 1.3 to 3.4, as determined by GPC measurement. The molecular weight distribution is obtained by gel permeation chromatography (GPC).

[0083] Maleimide Compound (C2) The maleimide compound (C2) is not particularly limited as long as it has an arylene structure in its molecule that is oriented and bonded at the meta position. Note that the maleimide compound (C2) has not only the arylene structure but also a maleimide group in its molecule. Examples of the arylene structure include an arylene structure in which a structure containing a maleimide group is bonded at the meta position (an arylene structure in which a structure containing a maleimide group is substituted at the meta position). The arylene structure is an arylene group oriented and bonded at the meta position, such as the group represented by the following formula (7). Examples of the arylene structure include m-arylene groups such as m-phenylene groups and m-naphthylene groups, and more specifically, the group represented by the following formula (7).

[0084]

[0085] Examples of maleimide compounds (C2) include maleimide compounds (C2-1) represented by the following formula (8), and more specifically, maleimide compounds (C2-1-1) represented by the following formula (9).

[0086]

[0087] In formula (8), Ar represents an arylene group oriented and bonded at the meta position. Ａ , R Ｂ , R Ｃ , and R Ｄ They are independent of each other. That is, R Ａ , R Ｂ , R Ｃ , and R Ｄ These may be the same group or different groups. Also, R Ａ , R Ｂ , R Ｃ , and R Ｄ R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and is preferably a hydrogen atom. Ｅ and R Ｆ They are independent of each other. That is, R Ｅ and R ＦThis may be the same group or different groups. Also, R Ｅ and R Ｆ represents an aliphatic hydrocarbon group. s represents a value greater than 1 and less than 5 (1 < s < 5).

[0088] The aforementioned arylene group is not particularly limited as long as it is an arylene group that is oriented and bonded to the meta position. Examples include m-arylene groups such as m-phenylene groups and m-naphthylene groups, and more specifically, the group represented by formula (7) above.

[0089] Examples of the C1-C5 alkyl group include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, and neopentyl group.

[0090] The aliphatic hydrocarbon group is a divalent group and may be acyclic or cyclic. Examples of the aliphatic hydrocarbon group include alkylene groups, and more specifically, methylene groups, methylmethylene groups, and dimethylmethylene groups. Among these, dimethylmethylene groups are preferred.

[0091] The maleimide compound (C2-1) represented by formula (8) is preferably such that the number of repeats, s, is greater than 1 and less than 5. This s is the average value of the number of repeats (degree of polymerization).

[0092]

[0093] In equation (9), s represents a value greater than 1 and less than 5. This s is the same as s in equation (8), and is the average value of the number of repetitions (degree of polymerization).

[0094] The maleimide compound (C2-1) represented by formula (8) and the maleimide compound (C2-1-1) represented by formula (9) may include a monofunctional compound represented by s = 0, as long as the average value of the number of repeats (degree of polymerization), s, is greater than 1 and less than 5, and may also include polyfunctional compounds such as heptafunctional or octafunctional compounds represented by s = 6 or more.

[0095] As the maleimide compound (C2), commercially available products can be used, for example, the solid content of MIR-5000-60T manufactured by Nippon Kayaku Co., Ltd. may be used.

[0096] As the maleimide compound (C2), the maleimide compounds exemplified above may be used alone, or two or more may be used in combination. For example, as the maleimide compound (C2), the maleimide compound (C2-1) represented by formula (8) may be used alone, or two or more maleimide compounds (C2-1) represented by formula (8) may be used in combination. When two or more maleimide compounds (C2-1) represented by formula (8) are used in combination, for example, a maleimide compound (C1) represented by formula (8), other than the maleimide compound (C2-1-1) represented by formula (9), may be used in combination with the maleimide compound (C2-1-1) represented by formula (9).

[0097] Maleimide Compound (C3) Maleimide compound (C3) is not particularly limited as long as it has an indane structure and an arylene structure bonded in a meta orientation within its molecule. In addition to the arylene structure and the indane structure, maleimide group is also present in the molecule of maleimide compound (C3). The indane structure is the same as the indane structure in maleimide compound (C1), and the arylene structure is the same as the arylene structure bonded in a meta orientation within maleimide compound (C2). Specific examples of maleimide compound (C3) include maleimide compounds represented by the following formulas (10) to (12).

[0098]

[0099] In equation (10), n represents a range of 0.95 to 10.

[0100]

[0101] In equation (11), n ​​represents a range of 0.95 to 10.

[0102]

[0103] In equation (12), n represents a range of 0.95 to 10.

[0104] As the maleimide compound (C3), commercially available products can be used, for example, the solid content in NE-X-9470S manufactured by DIC Corporation may be used.

[0105] Maleimide compound (C4) Maleimide compound (C4) is a maleimide compound having a maleimide equivalent of 500 g / mol or less, which is different from the polymaleimide resin (A), and which does not have either the indan structure or the arylene structure oriented and bonded at the meta position in its molecule. Examples of maleimide compound (C4) include phenylmethane maleimides such as 4,4'-diphenylmethanebismaleimide and polyphenylmethanemaleimide, phenylmaleimide compounds such as m-phenylenebismaleimide, bisphenol A diphenyl etherbismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, biphenylaralkyl type polymaleimide compounds, and N-alkylbismaleimide compounds having an aliphatic skeleton.

[0106] As the maleimide compound (C4), commercially available products may be used, for example, the solid content in MIR-3000-70MT manufactured by Nippon Kayaku Co., Ltd., BMI-1000, BMI-2300, BMI-4000, BMI-5100, BMI-TMH manufactured by Yamato Kasei Kogyo Co., Ltd., and BMI-689 manufactured by Designer Molecules Inc.

[0107] As the maleimide compound (C), any maleimide compound with a maleimide equivalent of 500 g / mol or less and different from the polymaleimide resin (A) can be used without particular limitation. The maleimide compounds exemplified above may be used alone or in combination of two or more. Furthermore, among the examples above, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide and phenylmethanemaleimide are preferred as maleimide compound (C) because they yield a resin composition with a higher glass transition temperature and a lower coefficient of thermal expansion.

[0108] As the maleimide compound (C), one of the maleimide compounds described above may be used alone, or two or more may be used in combination.

[0109] (High molecular weight compound (D)) The resin composition according to this embodiment may further contain a high molecular weight compound (D) having a number average molecular weight of 10,000 to 1,500,000, to the extent that it does not impair the effects of the present invention. By further containing the high molecular weight compound (D), a resin composition can be obtained in which the elastic modulus is lower and a cured product with a lower coefficient of thermal expansion is obtained. From this point of view, it is preferable that the resin composition further contains a high molecular weight compound (D). The high molecular weight compound (D) has a number average molecular weight of 10,000 to 1,500,000 and is a compound different from the polymaleimide resin (A) and the bismaleimide compound (B). Furthermore, if the resin composition further contains a maleimide compound (C), the high molecular weight compound (D) has a number average molecular weight of 10,000 to 1,500,000 and is a compound different from the polymaleimide resin (A), the bismaleimide compound (B), and the maleimide compound (C). The number-average molecular weight of the high molecular weight material (D) is 10,000 to 1,500,000, preferably 10,000 to 1,200,000, more preferably 10,000 to 1,000,000, even more preferably 10,000 to 900,000, and may also be 10,000 to 600,000, 10,000 to 300,000, or 10,000 to 200,000. The number-average molecular weight can be measured using any general molecular weight measurement method, specifically, values ​​measured using gel permeation chromatography (GPC).

[0110] As the high molecular weight material (D), for example, (meth)acrylic resin and styrene copolymers are preferred. The high molecular weight material (D) may be used alone or in combination. That is, as the high molecular weight material (D), it is preferable that it contains at least one of a (meth)acrylic resin with a number average molecular weight of 10,000 to 1,500,000 and a styrene polymer with a number average molecular weight of 10,000 to 1,500,000, and it is more preferable that it contains the (meth)acrylic resin.

[0111] ・(meth)acrylic resin Examples of the (meth)acrylic resin include acrylic block copolymers and acrylic random copolymers. Here, (meth)acrylic resin includes acrylic resin and methacrylic resin. Furthermore, the acrylic system may be either acrylic or methacrylic. Specifically, acrylic block copolymers include acrylic block copolymers and methacrylic block copolymers, and acrylic random copolymers include acrylic random copolymers and methacrylic random copolymers. The acrylic block copolymer is not particularly limited as long as it is a resin containing at least one of structural units derived from acrylic acid ester monomers and structural units derived from methacrylic acid ester monomers, that is, a resin containing structural units derived from (meth)acrylic acid ester monomers. Examples of the acrylic block copolymer include copolymers containing at least one of structural unit (d1) represented by the following formula (13) and structural unit (d2) represented by the following formula (14). Furthermore, the acrylic block copolymer is preferably a copolymer containing the structural unit (d1). In this case, the content of structural unit (d1) in the acrylic block copolymer is greater than 0% by mass.

[0112]

[0113]

[0114] In structural unit (d2), Y is not particularly limited as long as it is a hydrocarbon group having one or more carbon atoms. Examples of the hydrocarbon group include methyl group, ethyl group, butyl group, hexyl group, pentyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, lauryl group, stearyl group, docosyl group, isostearyl group, 1-methylheptyl group, 2-ethylhexyl group, phenoxyethyl group, 2-hydroxyethyl group, 2-hydroxypropyl group, 2-hydroxybutyl group, 4-hydroxybutyl group, 2-carboxyethyl group, isobornyl group, and isoamyl group. Hydrocarbon groups having four or more carbon atoms are preferred. Among these hydrocarbon groups, butyl group and 2-ethylhexyl group are preferred. Structural unit (d2) may contain these hydrocarbon groups individually or in combination of two or more. The structural unit (d2) is preferably a structural unit derived from butyl acrylate and a structural unit derived from 2-ethylhexyl acrylate. The structural unit (d1) is a structural unit derived from methyl methacrylate. Therefore, the acrylic block copolymer is preferably a block copolymer of a structural unit derived from methyl methacrylate as structural unit (d1) and at least one of a structural unit derived from butyl acrylate and a structural unit derived from 2-ethylhexyl acrylate as structural unit (d2). Examples of the block copolymer include a diblock of structural unit (d1) and structural unit (d2), and a triblock of structural unit (d1), with the triblock being preferred. Specifically, the acrylic block copolymer is more preferably a block copolymer of methyl methacrylate and butyl acrylate, and more preferably a triblock of methyl methacrylate, butyl acrylate, and methyl methacrylate. Furthermore, the structural unit (d1) in the acrylic block copolymer preferably becomes a hard segment, and its glass transition temperature is preferably, for example, 100 to 120°C.Furthermore, the structural unit (d2) in the acrylic block copolymer is a soft segment, and its glass transition temperature is preferably -60 to -40°C, and more preferably -50 to -40°C.

[0115] The acrylic block copolymer contains structural units (d1). Specifically, the content of structural units (d1) is more than 0% by mass, preferably more than 0% by mass and 20% by mass or less, more preferably 1 to 18% by mass, and even more preferably 11 to 18% by mass, relative to the acrylic block copolymer. If the content of structural units (d1) in the acrylic block copolymer is too low, the effect of adding the acrylic block copolymer becomes less pronounced, and it tends to be difficult to obtain a cured product with a low coefficient of thermal expansion from the resin composition. Therefore, when the content of structural units (d1) is within the above range, it tends to be easier to obtain a cured product with a low coefficient of thermal expansion from the resin composition.

[0116] The acrylic block copolymer may contain at least one of structural unit (d1) and structural unit (d2), and may also contain structural units other than structural unit (d1) and structural unit (d2) (other structural units) (d3). The other structural units (d3) are not particularly limited as long as they copolymerize with structural units (d1) and structural units (d2) contained in the acrylic block copolymer. That is, if the acrylic block copolymer contains structural unit (d1), the other structural unit (d3) may copolymerize with structural unit (d1). Also, if the acrylic block copolymer contains structural unit (d2), the other structural unit (d3) may copolymerize with structural unit (d2). Also, if the acrylic block copolymer contains both structural unit (d1) and structural unit (d2), the other structural unit may copolymerize with at least one of structural unit (d1) and structural unit (d2). Other structural units (d3) include, for example, structural units derived from methacrylate esters other than methyl methacrylate, structural units derived from methyl acrylate, structural units derived from ethyl acrylate, structural units derived from butyl acrylate, and structural units derived from styrene. Furthermore, structural units derived from methacrylate esters other than methyl methacrylate include, for example, structural units derived from ethyl methacrylate, structural units derived from butyl methacrylate, and structural units derived from propyl methacrylate.

[0117] The number-average molecular weight of the acrylic block copolymer is 10,000 or more, preferably 30,000 or more, and more preferably 40,000 or more. Furthermore, the number-average molecular weight of the acrylic block copolymer is preferably 1,500,000 or less, more preferably 1,200,000 or less, even more preferably 1,000,000 or less, and may also be 900,000 or less, 600,000 or less, 300,000 or less, or 200,000 or less. The acrylic block copolymer may be solid at 25°C or liquid at 25°C, but it is preferably solid at 25°C. The number-average molecular weight of the acrylic block copolymer is preferably such that it is solid at 25°C. If the number-average molecular weight is too low, the effect of adding the acrylic block copolymer becomes less pronounced, and it tends to be difficult to obtain a cured product with a low coefficient of thermal expansion from the resin composition. If the number-average molecular weight is too high, the compatibility with the polymaleimide resin (A) decreases too much, resulting in a failure to obtain a normal cured product, and the viscosity of the resin composition when it is made into a varnish, as well as the viscosity of the resin composition during heat molding, tend to become too high. Here, the number-average molecular weight can be any value measured by a general molecular weight measurement method, specifically, values ​​measured using gel permeation chromatography (GPC), etc.

[0118] The acrylic random copolymer is preferably a copolymer having a structure represented by the following formula (15), a structure represented by the following formula (16), and a structure represented by the following formula (17).

[0119]

[0120]

[0121]

[0122] In equations (15) to (17) above, x, y, and z represent mole fractions, and satisfy the following conditions: x + y + z ≤ 1, 0 < x ≤ 0.2, 0.6 ≤ y ≤ 0.95, and 0.05 ≤ z ≤ 0.2.

[0123] In the above formula (16), R ８ is a hydrogen atom or a methyl group, R ９ It contains at least one of a hydrogen atom, an alkyl group, a glycidyl group, and an epoxidized alkyl group, specifically a glycidyl group and an epoxidized alkyl group.

[0124] In the above formula (17), R １０ is a hydrogen atom or a methyl group, R １１ Ph (phenyl group), -COOCH ２ Ph or -COO(CH ２ ) ２ It is Ph.

[0125] Preferably, the acrylic random copolymer has as its main chain a structure represented by at least one formula (15), a structure represented by at least one formula (16), and a structure represented by at least one formula (15).

[0126] If the main chain of the acrylic random copolymer has a structure represented by formula (15), a structure represented by formula (16), and a structure represented by formula (17), the order in which the structures represented by formula (15), formula (16), and formula (17) are arranged is not particularly limited. In this case, the structure represented by formula (15) may or may not be continuous in the main chain of the acrylic random copolymer, the structure represented by formula (16) may or may not be continuous, and the structure represented by formula (17) may or may not be continuous.

[0127] Here, R in equation (16) ９ However, we will provide further explanation regarding the meaning of including at least one of a glycidyl group and an epoxidized alkyl group among a hydrogen atom, an alkyl group, a glycidyl group, and an epoxidized alkyl group. As a premise, R in one of the structures represented by the above formula (16) ９ There is one. The case in which the acrylic random copolymer has only one structure represented by formula (16) and the case in which it has two or more structures will be explained separately.

[0128] In the former case, that is, when the acrylic random copolymer has a structure represented by one of the above formulas (16), R ９ This is a glycidyl group or an epoxidized alkyl group.

[0129] In the latter case, that is, when the acrylic random copolymer has two or more structures represented by formula (16), R in at least one of the structures represented by formula (16) ９ R is a glycidyl group or an epoxidized alkyl group, and the remaining R in the structure represented by formula (16) ９ R is a hydrogen atom or an alkyl group. ９ However, since it is a glycidyl group or an epoxidized alkyl group, all R in the structure represented by formula (16) ９ However, a glycidyl group or an epoxidized alkyl group may also be used.

[0130] The structure represented by formula (17) is Ph (phenyl group), -COOCH ２ Ph, -COO(CH ２ ) ２ It has a pH. Ph, -COOCH ２ Ph, -COO(CH ２ ) ２ Since pH is thermally stable, the strength of the cured resin composition can be increased, and the heat resistance of laminates (metal-clad laminates and wiring boards) can be improved.

[0131] - Styrene polymers The styrene copolymer can be, for example, a copolymer obtained by copolymerizing one or more monomers containing styrene (styrene monomers) with one or more other monomers copolymerizable with the styrene monomers. The styrene copolymer can be a random copolymer or a block copolymer. The block copolymer can be a binary copolymer of structural units (repeating units) derived from the styrene monomer and structural units (repeating units) derived from the other copolymerizable monomers, or a ternary copolymer of structures (repeating units) derived from the styrene monomer, structural units (repeating units) derived from the other copolymerizable monomers, and structural units (repeating units) derived from the styrene monomer. The styrene polymer can also be a hydrogenated styrene copolymer obtained by hydrogenating the styrene copolymer as described above.

[0132] The styrene monomer is not particularly limited, but examples include styrene, styrene derivatives, styrene in which some of the hydrogen atoms of the benzene ring are substituted with alkyl groups, styrene in which some of the hydrogen atoms of the vinyl group are substituted with alkyl groups, vinyltoluene, α-methylstyrene, butylstyrene, dimethylstyrene, and isopropenyltoluene. The styrene monomer may be used individually or in combination of two or more.

[0133] The styrene polymer preferably has ethylene structural units and butylene structural units in its molecule, among the units obtained by copolymerizing the styrene monomer with one or more other monomers that can copolymerize. It is preferable that the polymer contains a larger proportion of butylene structures than ethylene structural units.

[0134] The ethylene structural unit is not particularly limited, but examples include structural units (repeating units) derived from other copolymerizable monomers that have an ethylene structure. The ethylene structural unit is a structure derived from a 1,4-bond of a conjugated diene monomer (conjugated dienes), and the atom or group bonded to the carbon of the -C-C-bond in the main chain is a hydrogen atom or a methyl group. Specific examples of the conjugated diene monomer include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-cyclohexadiene. Therefore, the ethylene structural units specifically include structural units having an ethylene structure among the structural units derived from the conjugated dienes, and more specifically, structural units having an ethylene structure (1,4-addition structural units) among the structural units (repeating units) derived from 1,3-butadiene.

[0135] The butylene structural unit is not particularly limited, but examples include structural units (repeating units) derived from other copolymerizable monomers that have a butylene structure. The butylene structural unit is at least one of a structure derived from a 1,2-bond of a conjugated diene monomer (conjugated dienes) and a structure derived from a 3,4-bond of a conjugated diene monomer (conjugated dienes), and at least one of the atoms or groups bonded to the carbon of the -C-C-bond of the main chain is a side chain having two or more carbon atoms. Therefore, the butylene structural unit specifically includes structural units derived from the conjugated dienes that have a butylene structure, and more specifically, structural units (repeating units) derived from 1,3-butadiene that have a butylene structure (at least one of a 1,2-addition structural unit and a 3,4-addition structural unit). The butylene structural unit may be, for example, a hydrogenated structural unit.

[0136] The styrene-based polymer may contain structural units (repeating units) derived from other copolymerizable monomers other than the ethylene structural unit and the butylene structural unit. Such other copolymerizable monomers are not particularly limited, but examples include olefins such as α-pinene, β-pinene, and dipentene, and non-conjugated dienes such as 1,4-hexadiene and 3-methyl-1,4-hexadiene.

[0137] Examples of the styrene-based polymers include methylstyrene (ethylene / butylene) methylstyrene copolymer, methylstyrene (ethylene-ethylene / propylene) methylstyrene copolymer, styrene isoprene copolymer, styrene isoprene styrene copolymer, styrene (ethylene / butylene) styrene copolymer, styrene (ethylene-ethylene / propylene) styrene copolymer, methylstyrene (styrene / butadiene random copolymer block) methylstyrene copolymer, styrene (styrene / butadiene random copolymer block) styrene copolymer, styrene butadiene styrene copolymer, styrene isobutylene styrene block copolymer, and styrene (butadiene / butylene) styrene copolymer. Furthermore, the styrene-based polymer may be a styrene-based polymer in which at least a portion of the styrene-based copolymer is hydrogenated. In addition, the styrene-based polymer may be a styrene-based polymer in which at least a portion of the styrene-based polymer is acid-modified, and specifically, a styrene-based polymer in which at least a portion of the styrene-based polymer is acid-modified with maleic anhydride.

[0138] When the acid-modified styrene polymer is used as the styrene polymer, the acid value is 2 mg CH ３ Preferably, the amount is 2-10 mg of CH4. ３ It is more preferable that the acid value of the styrene polymer is 2 mgCH. ３ Preferably, the polymer is a styrene polymer acid-modified with maleic anhydride so that the ONa / g level is 2 to 10 mgCHF. ３It is more preferable that the styrene polymer is acid-modified with maleic anhydride so that the acid value is ONa / g. When the acid value of the styrene polymer is within the above range, the effect of the high molecular weight (D), that is, the effect of reducing the thermal expansion coefficient of the cured resin composition, can be more favorably achieved. This is thought to be due to the increased compatibility of the styrene polymer with the polymaleimide resin (A). Here, the acid value is the amount of sodium methoxide (CH) required to neutralize the free acid in 1 g of the sample. ３ This is the amount (mg) of ONa.

[0139] The styrene-based polymer preferably has a number average molecular weight of 10,000 to 300,000, and more preferably 10,000 to 200,000. It is believed that having a molecular weight within this range allows for a high glass transition temperature of the cured resin composition, and also allows for an appropriate viscosity when the resin composition is made into a varnish, as well as when it is heat-molded.

[0140] As the styrene-based polymer mentioned above, one of the exemplified styrene-based polymers may be used alone, or two or more may be used in combination.

[0141] (Content) The content of the polymaleimide resin (A) is preferably 20 to 95% by mass, more preferably 40 to 95% by mass, and even more preferably 50 to 90% by mass, based on the total mass of the polymaleimide resin (A) and the benzoxazine compound (B).

[0142] When the resin composition contains a maleimide compound (C), the respective contents of the polymaleimide resin (A), benzoxazine compound (B), and maleimide compound (C) are preferably as follows: The content of the polymaleimide resin (A) is preferably 20 to 90% by mass, and more preferably 40 to 80% by mass, based on the total mass of the polymaleimide resin (A), benzoxazine compound (B), and maleimide compound (C). The content of the benzoxazine compound (B) is preferably 5 to 50% by mass, and more preferably 5 to 30% by mass, based on the total mass of the polymaleimide resin (A), benzoxazine compound (B), and maleimide compound (C). The content of the maleimide compound (C) is preferably 5 to 70% by mass, and more preferably 10 to 50% by mass, based on the total mass of the polymaleimide resin (A), benzoxazine compound (B), and maleimide compound (C).

[0143] When the resin composition contains a high molecular weight substance (D), the respective contents of the polymaleimide resin (A), benzoxazine compound (B), and high molecular weight substance (D) are preferably as follows: The content of the polymaleimide resin (A) is preferably 20 to 90% by mass, and more preferably 40 to 80% by mass, based on the total mass of the polymaleimide resin (A), benzoxazine compound (B), and high molecular weight substance (D). The content of the benzoxazine compound (B) is preferably 5 to 50% by mass, and more preferably 5 to 30% by mass, based on the total mass of the polymaleimide resin (A), benzoxazine compound (B), and high molecular weight substance (D). The content of the high molecular weight substance (D) is preferably 40% by mass or less, more preferably 5 to 35% by mass, and even more preferably 10 to 30% by mass, based on the total mass of the polymaleimide resin (A), benzoxazine compound (B), and high molecular weight substance (D).

[0144] When the resin composition contains a maleimide compound (C) and a high molecular weight compound (D), the respective contents of the polymaleimide resin (A), benzoxazine compound (B), maleimide compound (C), and high molecular weight compound (D) are preferably as follows: The content of the polymaleimide resin (A) is preferably 20 to 80% by mass, and more preferably 40 to 75% by mass, based on the total mass of the polymaleimide resin (A), benzoxazine compound (B), maleimide compound (C), and high molecular weight compound (D). The content of the benzoxazine compound (B) is preferably 5 to 40% by mass, and more preferably 5 to 30% by mass, based on the total mass of the polymaleimide resin (A), benzoxazine compound (B), maleimide compound (C), and high molecular weight compound (D). The content of maleimide compound (C) is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass, based on the total mass of the polymaleimide resin (A), benzoxazine compound (B), maleimide compound (C), and high molecular weight material (D). The content of high molecular weight material (D) is preferably 40% by mass or less, more preferably 5 to 35% by mass, and even more preferably 10 to 30% by mass, based on the total mass of the polymaleimide resin (A), benzoxazine compound (B), maleimide compound (C), and high molecular weight material (D).

[0145] By satisfying the aforementioned content range, a resin composition can be suitably obtained that cured product has a high glass transition temperature and low thermal expansion coefficient and water absorption rate.

[0146] (Other Components) The resin composition may optionally contain components other than the polymaleimide resin (A), benzoxazine compound (B), maleimide compound (C), and high molecular weight material (D), as long as the effects of the present invention are not impaired. Other components contained in the resin composition according to this embodiment may further include, for example, additives such as curing agents, inorganic fillers, reaction initiators, reaction accelerators, catalysts, polymerization retarders, polymerization inhibitors, dispersants, leveling agents, coupling agents, defoamers, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, dyes and pigments, and lubricants.

[0147] As described above, the resin composition according to this embodiment may contain a curing agent. Examples of the curing agent include a curing agent that reacts with at least one of the polymaleimide resin (A) and the benzoxazine compound (B) to contribute to the curing of the resin composition. Specifically, examples of the curing agent include allyl compounds, methacrylate compounds, acrylate compounds, acenaphthylene compounds, vinyl compounds, polyphenylene ether compounds, cyanate ester compounds, and active ester compounds.

[0148] The allyl compounds are compounds having an allyl group in their molecule, and examples include triallyl isocyanurate compounds such as triallyl isocyanurate (TAIC), diallyl bisphenol compounds, and diallyl phthalate (DAP).

[0149] The methacrylate compound is a compound having a methacryloyl group in its molecule, and examples include monofunctional methacrylate compounds having one methacryloyl group in their molecule, and polyfunctional methacrylate compounds having two or more methacryloyl groups in their molecule. Examples of the monofunctional methacrylate compound include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Examples of the polyfunctional methacrylate compound include dimethacrylate compounds such as tricyclodecanedimethanol dimethacrylate (DCP).

[0150] The acrylate compound is a compound having an acryloyl group in its molecule, and examples include monofunctional acrylate compounds having one acryloyl group in their molecule, and polyfunctional acrylate compounds having two or more acryloyl groups in their molecule. Examples of the monofunctional acrylate compound include methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. Examples of the polyfunctional acrylate compound include diacrylate compounds such as tricyclodecanedimethanol diacrylate.

[0151] The aforementioned acenaphthylene compound is a compound having an acenaphthylene structure in its molecule. Examples of the aforementioned acenaphthylene compound include acenaphthylene, alkylacenaphthylenes, halogenated acenaphthylenes, and phenylacenaphthylenes. Examples of the aforementioned alkylacenaphthylenes include 1-methylacenaphthylene, 3-methylacenaphthylene, 4-methylacenaphthylene, 5-methylacenaphthylene, 1-ethylacenaphthylene, 3-ethylacenaphthylene, 4-ethylacenaphthylene, and 5-ethylacenaphthylene. Examples of the halogenated acenaphthylenes include 1-chloroacenaphthylene, 3-chloroacenaphthylene, 4-chloroacenaphthylene, 5-chloroacenaphthylene, 1-bromoacenaphthylene, 3-bromoacenaphthylene, 4-bromoacenaphthylene, and 5-bromoacenaphthylene. Examples of the phenylacenaphthylenes include 1-phenylacenaphthylene, 3-phenylacenaphthylene, 4-phenylacenaphthylene, and 5-phenylacenaphthylene. The acenaphthylene compound may be a monofunctional acenaphthylene compound having one acenaphthylene structure in the molecule, as described above, or a polyfunctional acenaphthylene compound having two or more acenaphthylene structures in the molecule.

[0152] The vinyl compound is a compound having a vinyl group in its molecule. Examples of the vinyl compound include monofunctional vinyl compounds (monovinyl compounds) having one vinyl group in their molecule, and polyfunctional vinyl compounds having two or more vinyl groups in their molecule. Examples of the polyfunctional vinyl compound include polyfunctional aromatic vinyl compounds and vinyl hydrocarbon compounds. Examples of the vinyl hydrocarbon compounds include divinylbenzene and polybutadiene compounds.

[0153] The polyphenylene ether compound is a compound having a polyphenylene ether chain in its molecule. Examples of the polyphenylene ether compound include a polyphenylene ether compound having an unsaturated double bond in its molecule. More specifically, examples of the polyphenylene ether compound include a polyphenylene ether compound having a vinyl benzyl group (ethenyl benzyl group) in its molecule (vinyl benzyl-modified polyphenylene ether), a polyphenylene ether compound having an acryloyl group in its molecule (acrylic-modified polyphenylene ether), and a polyphenylene ether compound having a methacryloyl group in its molecule (methacrylic-modified polyphenylene ether).

[0154] The cyanate ester compound is a compound having a cyanate group in its molecule, and examples include 2,2-bis(4-cyanatephenyl)propane, bis(3,5-dimethyl-4-cyanatephenyl)methane, and 2,2-bis(4-cyanatephenyl)ethane.

[0155] The aforementioned active ester compounds are compounds having highly reactive ester groups in their molecules, and examples include benzenecarboxylic acid active esters, benzenedicarboxylic acid active esters, benzenetricarboxylic acid active esters, benzenetetracarboxylic acid active esters, naphthalenecarboxylic acid active esters, naphthalenedicarboxylic acid active esters, naphthalentricarboxylic acid active esters, naphthalenetetracarboxylic acid active esters, fluorenecarboxylic acid active esters, fluorentricarboxylic acid active esters, and fluorenetetracarboxylic acid active esters.

[0156] The curing agent may be used alone or in combination of two or more types.

[0157] As described above, the resin composition according to this embodiment may contain an inorganic filler. The inorganic filler is not particularly limited as long as it is an inorganic filler that can be used as an inorganic filler contained in the resin composition. Examples of the inorganic filler include metal oxide fillers, metal hydroxide fillers, molybdate fillers, nitride fillers, titanate fillers, magnesium carbonate fillers such as anhydrous magnesium carbonate fillers, calcium carbonate fillers, quartz glass fillers, talc fillers, aluminum borate fillers, and barium sulfate fillers. Examples of the metal oxide fillers include silica fillers, alumina fillers, titanium oxide fillers, magnesium oxide fillers, and mica fillers. Examples of the silica fillers include crushed silica, spherical silica such as molten spherical silica, and silica particles. Examples of the metal hydroxide fillers include magnesium hydroxide fillers and aluminum hydroxide fillers. Examples of the molybdate fillers include zinc molybdate fillers, calcium molybdate fillers, and magnesium molybdate fillers. Examples of the nitride fillers include aluminum nitride fillers and boron nitride fillers. Examples of the titanate fillers include barium titanate fillers, strontium titanate fillers, calcium titanate fillers, and aluminum titanate fillers. Among these, silica fillers, metal hydroxide fillers such as magnesium hydroxide fillers and aluminum hydroxide fillers, aluminum oxide fillers, boron nitride fillers, strontium titanate fillers, calcium titanate fillers, and zinc molybdate fillers are preferred, with silica fillers being more preferred. The silica fillers are not particularly limited, but for example, they may be solid silica particles or hollow silica particles. Furthermore, the inorganic fillers may be used alone or in combination of two or more types.When using two or more of the aforementioned inorganic fillers in combination, silica filler may be used in combination with one or more other inorganic fillers, and it is preferable to use silica filler in combination with zinc molybdate filler. Furthermore, the inorganic filler may be, for example, talc filler supporting molybthenate in the molybdate filler.

[0158] The inorganic filler may be a surface-treated inorganic filler or an untreated inorganic filler. Examples of surface treatments include treatment with a silane coupling agent.

[0159] The silane coupling agent is not particularly limited, and examples include silane coupling agents having at least one functional group selected from the group consisting of vinyl group, styryl group, methacryloyl group, acryloyl group, phenylamino group, isocyanurate group, ureido group, mercapto group, isocyanate group, epoxy group, and acid anhydride group. That is, this silane coupling agent has at least one of vinyl group, styryl group, methacryloyl group, acryloyl group, phenylamino group, isocyanurate group, ureido group, mercapto group, isocyanate group, epoxy group, and acid anhydride group as a reactive functional group, and further includes compounds having hydrolyzable groups such as methoxy group and ethoxy group.

[0160] Examples of silane coupling agents that have a vinyl group include vinyltriethoxysilane and vinyltrimethoxysilane. Examples of silane coupling agents that have a styryl group include p-styryltrimethoxysilane and p-styryltriethoxysilane. Examples of silane coupling agents that have a methacryloyl group include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropylethyldiethoxysilane. Examples of silane coupling agents that have an acryloyl group include 3-acryloxypropyltrimethoxysilane and 3-acryloxypropyltriethoxysilane. Examples of silane coupling agents having a phenylamino group include N-phenyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltriethoxysilane.

[0161] The average particle diameter of the inorganic filler is not particularly limited, but is preferably 0.05 to 10 μm, and more preferably 0.1 to 8 μm. Here, the average particle diameter refers to the volume-average particle diameter. The volume-average particle diameter can be measured, for example, by laser diffraction.

[0162] When the inorganic filler is included, the amount of the inorganic filler is preferably 100 to 300 parts by mass, and more preferably 100 to 250 parts by mass, per 100 parts by mass of organic components (other than the inorganic filler in the resin composition).

[0163] As described above, the resin composition according to this embodiment may contain a reaction initiator. Even if the resin composition does not contain a reaction initiator, the curing reaction can proceed. However, depending on the process conditions, it may be difficult to raise the temperature until curing proceeds, so a reaction initiator may be added. The reaction initiator is not particularly limited as long as it can promote the curing reaction of the resin composition, and examples include peroxides and organic azo compounds. Examples of peroxides include dicumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexine, and benzoyl peroxide. Examples of organic azo compounds include azobisisobutyronitrile. In addition, metal carboxylate salts can be used in combination as needed. By doing so, the curing reaction can be further promoted. Among these, α,α'-bis(t-butylperoxy-m-isopropyl)benzene is preferably used. α,α'-bis(t-butylperoxy-m-isopropyl)benzene has a relatively high reaction initiation temperature, which can suppress the acceleration of the curing reaction at times when curing is not required, such as during prepreg drying, thereby suppressing the deterioration of the shelf life of the resin composition. Furthermore, because α,α'-bis(t-butylperoxy-m-isopropyl)benzene has low volatility, it does not volatilize during prepreg drying or storage, resulting in good stability. The reaction initiator may be used alone or in combination of two or more types.

[0164] As described above, the resin composition according to this embodiment may contain a coupling agent. The coupling agent may be contained in the resin composition, or it may be contained in the inorganic filler as a coupling agent pre-surface-treated. In the case of a prepreg, the prepreg may contain a coupling agent pre-surface-treated on the fibrous substrate. Examples of the coupling agent include those similar to the coupling agent used when surface-treating the inorganic filler as described above.

[0165] As described above, the resin composition according to this embodiment may contain a flame retardant. By including a flame retardant, the flame retardancy of the cured resin composition can be enhanced. The flame retardant is not particularly limited. Specifically, in fields where halogen-based flame retardants such as brominated flame retardants are used, for example, ethylenedipentabromobenzene, ethylenebistetrabromoimide, decabromodiphenyl oxide, tetradecabromodiphenoxybenzene, and bromostyrene compounds that react with the polymerizable compound are preferred, each having a melting point of 300°C or higher. It is believed that by using a halogen-based flame retardant, the desorption of halogens at high temperatures can be suppressed, thereby suppressing a decrease in heat resistance. In addition, in fields where halogen-free is required, a phosphorus-containing flame retardant (phosphorus-based flame retardant) may be used. The phosphorus-based flame retardant is not particularly limited, but examples include phosphate ester-based flame retardants, phosphazene-based flame retardants, bisdiphenylphosphine oxide-based flame retardants, and phosphinate-based flame retardants. Specific examples of phosphate ester-based flame retardants include condensed phosphate esters of dixylenyl phosphate. Specific examples of phosphazene-based flame retardants include phenoxyphosphazene. Specific examples of bis-diphenylphosphine oxide-based flame retardants include xylylene bis-diphenylphosphine oxide. Specific examples of phosphinate-based flame retardants include, for example, phosphinate metal salts of aluminum dialkylphosphinate. The flame retardants described above may be used individually or in combination of two or more.

[0166] The resin composition according to this embodiment, when cured, yields a cured product with a high glass transition temperature, low thermal expansion coefficient, and low water absorption. Furthermore, as described later, the resin composition is used as a varnish to manufacture prepregs, metal-clad laminates, wiring boards, resin-coated metal foils, and resin-coated films. Therefore, high stability when made into a varnish makes it easier to manufacture these products. For example, when manufacturing wiring boards, it is possible to suitably manufacture wiring boards equipped with an insulating layer containing a cured product with a high glass transition temperature, low thermal expansion coefficient, and low water absorption. The resin composition according to this embodiment not only yields a cured product with a high glass transition temperature, low thermal expansion coefficient, and low water absorption, but also has high stability when made into a varnish (varnish stability). Therefore, when using the resin composition, a cured product with a high glass transition temperature, low thermal expansion coefficient, and low water absorption can be suitably obtained. Furthermore, it is possible to suitably manufacture metal-clad laminates and wiring boards equipped with an insulating layer containing a cured product with a high glass transition temperature, low thermal expansion coefficient, and low water absorption.

[0167] (Applications) The resin composition is used in the manufacture of prepregs, as described later. The resin composition is also used in the formation of resin layers in resin-coated metal foils and resin-coated films, and insulating layers in metal-clad laminates and wiring boards.

[0168] (Manufacturing Method) The method for manufacturing the resin composition is not particularly limited, and examples include mixing a polymaleimide resin (A), a benzoxazine compound (B), and, if necessary, the other components in predetermined amounts. In addition, when obtaining a varnish-like composition containing an organic solvent, the method described later may be used.

[0169] [Prepreg, metal-clad laminate, wiring board, resin-coated metal foil, and resin-coated film] By using the resin composition according to this embodiment, prepreg, metal-clad laminate, wiring board, resin-coated metal foil, and resin-coated film can be obtained as follows.

[0170] (Prepreg) Figure 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to an embodiment of the present invention.

[0171] As shown in Figure 1, the prepreg 1 according to this embodiment comprises the resin composition or a semi-cured product 2 of the resin composition and a fibrous base material 3. This prepreg 1 comprises the resin composition or a semi-cured product 2 of the resin composition and a fibrous base material 3 present in the resin composition or the semi-cured product 2 of the resin composition.

[0172] In this embodiment, a semi-cured product refers to a resin composition that has been partially cured to the extent that it can be further cured. In other words, a semi-cured product is a resin composition that has been partially cured (stage B). For example, when a resin composition is heated, its viscosity gradually decreases at first, and then curing begins, causing the viscosity to gradually increase. In such a case, a semi-cured state would be the state between the time the viscosity begins to increase and before it is completely cured.

[0173] The prepreg obtained using the resin composition according to this embodiment may include a semi-cured product of the resin composition as described above, or it may include the uncured resin composition itself. That is, it may be a prepreg comprising a semi-cured product of the resin composition (the resin composition in stage B) and a fibrous substrate, or it may be a prepreg comprising the uncured resin composition (the resin composition in stage A) and a fibrous substrate. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried.

[0174] When manufacturing the prepreg, the resin composition 2 is often prepared in a varnish-like form for impregnation into the fibrous substrate 3, which is the base material for forming the prepreg. That is, the resin composition 2 is usually a resin varnish prepared in a varnish-like form. Such a varnish-like resin composition (resin varnish) is prepared, for example, as follows.

[0175] First, each component that can be dissolved in an organic solvent is added to the organic solvent and dissolved. Heating may be used as needed during this process. Then, components that cannot be dissolved in the organic solvent are added as needed, and the mixture is dispersed using a ball mill, bead mill, planetary mixer, roll mill, etc., until a predetermined dispersion state is reached, thereby preparing a varnish-like resin composition. The organic solvent used here is not particularly limited as long as it dissolves copolymer (A) and copolymer (B), etc., and does not inhibit the curing reaction. Specifically, examples include toluene and methyl ethyl ketone (MEK).

[0176] Specific examples of the fibrous substrate include glass cloth, aramid cloth, polyester cloth, liquid crystal polymer (LCP) cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. When glass cloth is used, a laminate with excellent mechanical strength can be obtained, and flattened glass cloth is particularly preferred. Specific examples of the flattening process include a method in which the glass cloth is continuously pressed with a press roll at an appropriate pressure to flatten the yarn. The thickness of the fibrous substrate is generally 0.01 mm to 0.3 mm. The glass fibers constituting the glass cloth are not particularly limited, but examples include Q glass, NE glass, NER glass, NEZ glass, E glass, S glass, T glass, L glass, and L2 glass. The surface of the fibrous substrate may also be surface-treated with a silane coupling agent. The silane coupling agent is not particularly limited, but examples include a silane coupling agent having at least one group selected from the group consisting of vinyl, acryloyl, methacryloyl, styryl, amino, and epoxy groups in its molecule.

[0177] The method for manufacturing the prepreg is not particularly limited as long as it allows for the production of the prepreg. Specifically, when manufacturing the prepreg, the resin composition according to this embodiment is often prepared in a varnish-like state and used as a resin varnish, as described above.

[0178] A specific method for manufacturing the prepreg 1 is to impregnate a fibrous substrate 3 with the resin composition 2, for example, a resin composition 2 prepared in the form of a varnish, and then dry it. The resin composition 2 is impregnated into the fibrous substrate 3 by immersion, coating, etc. It is also possible to repeat the impregnation process multiple times as needed. Furthermore, by repeating the impregnation process using multiple resin compositions with different compositions and concentrations, it is possible to adjust the final composition and amount of impregnation to the desired level.

[0179] The fibrous substrate 3 impregnated with the resin composition (resin varnish) 2 is heated under desired heating conditions, for example, at 40°C to 180°C for 1 minute to 10 minutes. Heating yields a prepreg 1 in either a pre-cured state (Stage A) or a semi-cured state (Stage B). Heating can also cause organic solvents to volatilize from the resin varnish, reducing or removing them.

[0180] (Metal-clad laminate) Figure 2 is a schematic cross-sectional view showing an example of a metal-clad laminate 11 according to an embodiment of the present invention.

[0181] As shown in Figure 2, the metal-clad laminate 11 according to this embodiment has an insulating layer 12 containing a cured product of the resin composition and a metal foil 13 provided on the insulating layer 12. Examples of the metal-clad laminate 11 include a metal-clad laminate composed of an insulating layer 12 containing a cured product of the prepreg 1 shown in Figure 1 and a metal foil 13 laminated together with the insulating layer 12. The insulating layer 12 may be made of a cured product of the resin composition or a cured product of the prepreg. The thickness of the metal foil 13 is not particularly limited and varies depending on the performance required of the final printed circuit board. The thickness of the metal foil 13 can be set appropriately according to the desired purpose, and is preferably, for example, 0.2 to 70 μm. Examples of the metal foil 13 include copper foil and aluminum foil, and if the metal foil is thin, it may be a carrier-equipped copper foil with a release layer and carrier to improve handling.

[0182] The method for manufacturing the metal-clad laminate 11 is not particularly limited as long as it can be manufactured. Specifically, one method is to manufacture the metal-clad laminate 11 using the prepreg 1. This method involves stacking one or more prepreg 1 sheets, further stacking metal foil 13 such as copper foil on both the top and bottom surfaces or one or both surfaces, and then heat-pressure-molding the metal foil 13 and the prepreg 1 to laminate and integrate them, thereby producing a laminate 11 with metal foil on both sides or one side. In other words, the metal-clad laminate 11 is obtained by laminating the metal foil 13 onto the prepreg 1 and then heat-pressure-molding it. The heating and pressing conditions can be appropriately set depending on the thickness of the metal-clad laminate 11 and the type of resin composition contained in the prepreg 1. For example, the temperature can be 170 to 230°C, the pressure 0.5 to 5 MPa, and the time 60 to 150 minutes. The metal-clad laminate may also be manufactured without using prepreg. For example, one method involves applying a varnish-like resin composition onto a metal foil to form a layer containing the resin composition on the metal foil, and then heating and pressurizing it.

[0183] (Wiring board) Figure 3 is a schematic cross-sectional view showing an example of a wiring board 21 according to an embodiment of the present invention.

[0184] As shown in Figure 3, the wiring board 21 according to this embodiment has an insulating layer 12 containing a cured product of the resin composition and wiring 14 provided on the insulating layer 12. Examples of the wiring board 21 include a wiring board composed of an insulating layer 12 made by curing the prepreg 1 shown in Figure 1, and wiring 14 laminated together with the insulating layer 12 and formed by partially removing the metal foil 13. Furthermore, the insulating layer 12 may be made of a cured product of the resin composition, or it may be made of a cured product of the prepreg.

[0185] The method for manufacturing the wiring board 21 is not particularly limited as long as it can be manufactured. Specifically, a method for manufacturing the wiring board 21 using the prepreg 1 can be mentioned. For example, this method involves etching the metal foil 13 on the surface of the metal-clad laminate 11 manufactured as described above to form wiring, thereby manufacturing a wiring board 21 in which wiring is provided as a circuit on the surface of the insulating layer 12. That is, the wiring board 21 is obtained by partially removing the metal foil 13 on the surface of the metal-clad laminate 11 to form a circuit. In addition to the above method, other methods for forming circuits include, for example, circuit formation by the semi-additive process (SAP) or the modified semi-additive process (MSAP).

[0186] (Metal foil with resin) Figure 4 is a schematic cross-sectional view showing an example of a metal foil with resin 31 according to this embodiment.

[0187] As shown in Figure 4, the resin-coated metal foil 31 according to this embodiment comprises a resin layer 32 containing the resin composition or a semi-cured product of the resin composition, and a metal foil 13. 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 comprises the resin layer 32 and the metal foil 13 laminated together with the resin layer 32. In addition, the resin-coated metal foil 31 may have other layers between the resin layer 32 and the metal foil 13.

[0188] The resin layer 32 may contain a semi-cured product of the resin composition as described above, or it may contain the uncured resin composition. That is, the resin-coated metal foil 31 may comprise a resin layer containing a semi-cured product of the resin composition (the resin composition in stage B) and a metal foil, or it may comprise a resin layer containing the uncured resin composition (the resin composition in stage A) and a metal foil. Furthermore, the resin layer may contain the resin composition or a semi-cured product of the resin composition, and may or may not contain a fibrous substrate. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried. Furthermore, the fibrous substrate may be the same as the fibrous substrate of a prepreg.

[0189] The aforementioned metal foil can be any metal foil used in metal-clad laminates or resin-coated metal foils without limitation. Examples of such metal foils include copper foil and aluminum foil.

[0190] The resin-coated metal foil 31 may be provided with a cover film or the like, if necessary. Providing a cover film can prevent the incorporation of foreign matter. The cover film is not particularly limited, but examples include polyolefin film, polyester film, polymethylpentene film, and films formed by providing a release agent layer on these films.

[0191] The method for producing the resin-coated metal foil 31 is not particularly limited as long as it can produce the resin-coated metal foil 31. Examples of methods for producing the resin-coated metal foil 31 include applying the varnish-like resin composition (resin varnish) onto the metal foil 13 and heating it. The varnish-like resin composition is applied onto the metal foil 13, for example, by using a bar coater. The applied resin composition is heated, for example, at a temperature of 40°C to 180°C for 0.1 minutes to 10 minutes. The heated resin composition is formed on the metal foil 13 as an uncured resin layer 32. The heating can cause the organic solvent to volatilize from the resin varnish, thereby reducing or removing the organic solvent.

[0192] (Resin-coated film) Figure 5 is a schematic cross-sectional view showing an example of a resin-coated film 41 according to this embodiment.

[0193] As shown in Figure 5, the resin-coated film 41 according to this embodiment comprises a resin layer 42 containing the resin composition or a semi-cured product of the resin composition, and a support film 43. This resin-coated film 41 comprises the resin layer 42 and a support film 43 laminated together with the resin layer 42. The resin-coated film 41 may also have other layers between the resin layer 42 and the support film 43.

[0194] The resin layer 42 may contain a semi-cured product of the resin composition as described above, or it may contain the uncured resin composition. That is, the resin-coated film 41 may comprise a resin layer containing a semi-cured product of the resin composition (the resin composition of stage B) and a support film, or it may comprise a resin layer containing the uncured resin composition (the resin composition of stage A) and a support film. Furthermore, the resin layer may contain the resin composition or a semi-cured product of the resin composition, and may or may not contain a fibrous substrate. Furthermore, the resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried. Furthermore, the fibrous substrate may be the same as the fibrous substrate of the prepreg.

[0195] The support film 43 can be any support film used for resin-coated films without limitation. Examples of such support films include polyester film, polyethylene terephthalate (PET) film, polyimide film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, polyamide film, polycarbonate film, and electrically insulating films such as polyarylate film.

[0196] The resin-coated film 41 may be provided with a cover film or the like, if necessary. Providing a cover film can prevent the incorporation of foreign matter. The cover film is not particularly limited, but examples include polyolefin film, polyester film, and polymethylpentene film.

[0197] The support film and the cover film may be subjected to surface treatments such as matte treatment, corona treatment, release treatment, and roughening treatment, as needed.

[0198] The method for manufacturing the resin-coated film 41 is not particularly limited as long as it can be manufactured. Examples of methods for manufacturing the resin-coated film 41 include applying the varnish-like resin composition (resin varnish) onto a support film 43 and heating it. The varnish-like resin composition is applied onto the support film 43, for example, by using a bar coater. The applied resin composition is heated, for example, at a temperature of 40°C to 180°C for 0.1 minutes to 10 minutes. The heated resin composition is formed on the support film 43 as an uncured resin layer 42. The heating can cause organic solvents to volatilize from the resin varnish, thereby reducing or removing the organic solvents.

[0199] The resin composition according to this embodiment, when cured, becomes a cured product with a high glass transition temperature, low thermal expansion coefficient, and low water absorption. Therefore, when the prepreg is cured, it becomes a cured product with a high glass transition temperature, low thermal expansion coefficient, and low water absorption. The resin-coated metal foil and the resin-coated film are, respectively, resin-coated metal foil and the resin-coated film, each comprising a resin layer that, when cured, becomes an insulating layer containing the cured product. The metal-clad laminate and the wiring board are, respectively, metal-clad laminate and wiring board, each comprising an insulating layer containing the cured product. The prepreg, the resin-coated film, the resin-coated metal foil, and the metal-clad laminate can be suitably used in the manufacture of the wiring board, and can also be used, for example, in the manufacture of a multilayer wiring board. For example, with the resin-coated film, a multilayer wiring board can be manufactured by laminating it on the wiring board and then peeling off the support film, or by laminating it on the wiring board after peeling off the support film. With the resin-coated metal foil, a multilayer wiring board can be manufactured, for example, by laminating it on the wiring board. In this way, by using the resin-coated film and the resin-coated metal foil, etc., a multilayer wiring board having an insulating layer containing the cured material can be manufactured.

[0200] As described above, this specification discloses various aspects of technology, the main technologies being summarized below.

[0201] A resin composition according to a first aspect of the present invention is a resin composition comprising a polymaleimide resin (A) having a substructure represented by general formula (1), a substructure represented by general formula (T-1) chemically bonded to the substructure represented by general formula (1), and a substructure represented by general formula (T-2) chemically bonded to the substructure represented by general formula (1), and a benzoxazine compound (B).

[0202] A resin composition according to a second aspect of the present invention is a resin composition according to a first aspect of the present invention in which the benzoxazine compound (B) is a benzoxazine compound having an allyl group in its molecule.

[0203] A third aspect of the present invention is a resin composition according to the first or second aspect of the present invention, further comprising a maleimide compound (C) different from the polymaleimide resin (A), wherein the maleimide equivalent is 500 g / mol or less.

[0204] A resin composition according to a fourth aspect of the present invention is a resin composition according to a first or second aspect of the present invention, further comprising a high molecular weight material (D) having a number average molecular weight of 10,000 or more and 1,500,000 or less.

[0205] The fifth aspect of the present invention is a resin composition according to the fourth aspect of the present invention, wherein the high molecular weight material (D) is a resin composition comprising at least one of (meth)acrylic resin and styrene copolymer.

[0206] The resin composition according to the sixth aspect of the present invention is a resin composition according to the fourth or fifth aspect of the present invention in which the high molecular weight material (D) is a resin composition containing a (meth)acrylic resin.

[0207] The seventh aspect of the present invention is a resin composition according to any one of the fourth to sixth aspects of the present invention, wherein the content of the high molecular weight material (D) is 40% by mass or less with respect to the total mass of the polymaleimide resin (A), the benzoxazine compound (B), and the high molecular weight material (D).

[0208] The eighth aspect of the present invention is a resin composition that further comprises a high molecular weight material (D) having a number average molecular weight of 10,000 or more and 1,500,000 or less, in the resin composition according to the third aspect.

[0209] The resin composition according to the ninth aspect of the present invention is a resin composition according to the eighth aspect in which the content of the high molecular weight material (D) is 40% by mass or less with respect to the total mass of the polymaleimide resin (A), the benzoxazine compound (B), the maleimide compound (C), and the high molecular weight material (D).

[0210] A prepreg according to the tenth aspect of the present invention is a prepreg comprising a resin composition according to any one of the first to nine aspects of the present invention or a semi-cured product of the resin composition and a fibrous substrate.

[0211] A resin-coated film according to the eleventh aspect of the present invention is a resin-coated film comprising a resin layer containing a resin composition according to any one of the first to nine aspects of the present invention or a semi-cured product of the resin composition, and a support film.

[0212] A resin-coated metal foil according to the twelfth aspect of the present invention is a resin-coated metal foil comprising a resin layer containing a resin composition according to any one of the first to nine aspects of the present invention or a semi-cured product of the resin composition, and a metal foil.

[0213] A metal-clad laminate according to a thirteenth aspect of the present invention is a metal-clad laminate comprising an insulating layer containing a cured product of a resin composition according to any one of the first to nine aspects of the present invention, and a metal foil.

[0214] A metal-clad laminate according to a fourteenth aspect of the present invention is a metal-clad laminate comprising an insulating layer containing a cured prepreg according to a tenth aspect of the present invention and a metal foil.

[0215] A wiring board according to the 15th aspect of the present invention is a wiring board comprising an insulating layer containing a cured product of a resin composition according to any one of the first to nine aspects of the present invention, and wiring.

[0216] A wiring board according to the sixteenth aspect of the present invention is a wiring board comprising an insulating layer containing a cured prepreg according to the tenth aspect of the present invention and wiring.

[0217] According to the present invention, it is possible to provide a resin composition that yields a cured product with a high glass transition temperature and low thermal expansion coefficient and water absorption rate. Furthermore, according to the present invention, it is possible to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that can be obtained using the resin composition.

[0218] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited thereto.

[0219] [Examples 1-6 and Comparative Examples 1-3] In these examples and comparative examples, the components used in preparing the resin composition will be described.

[0220] (Polymaleimide resin (A)) Polymaleimide resin: A polymaleimide resin having a substructure represented by general formula (1), a substructure represented by general formula (T-1) that is chemically bonded to the substructure represented by general formula (1), and a substructure represented by general formula (T-2) that is chemically bonded to the substructure represented by general formula (1) (NE-X-9600 manufactured by DIC Corporation).

[0221] (Benzoxazine compound (B)) Benzooxazine compound: A benzooxazine compound having an allyl group in its molecule (represented by formula (4) above, R ６ and R ７ (ALP-d) is a benzooxazine compound in which X is an allyl group, X is a methylene group, and q and r are 1.

[0222] (Maleimide Compound (C)) Maleimide Compound 1: Phenylmethanemaleimide (BMI-2300 manufactured by Yamato Chemical Industries, Ltd., maleimide equivalent: 180 g / mol) Maleimide Compound 2: 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide (BMI-5100 manufactured by Yamato Chemical Industries, Ltd., maleimide equivalent: 222 g / mol) Maleimide Compound 3: Maleimide compound having an indane structure and an arylene structure oriented and bonded to the meta position in its molecule (the maleimide compound represented by formula (10) above, solid content in NE-X-9470S manufactured by DIC Corporation)

[0223] (High molecular weight (D)) (Meth)acrylic resin: Triblock copolymer of methyl methacrylate, n-butyl acrylate, and methyl methacrylate (Clarity LA3320 manufactured by Kuraray Co., Ltd., number average molecular weight Mn: 47000)

[0224] (Curing agent) Modified PPE: A polyphenylene ether compound having a methacryloyl group in its molecule (SA9000 manufactured by SABIC Innovative Plastics, a modified polyphenylene ether in which the terminal hydroxyl groups of polyphenylene ether are modified with methacryloyl groups, weight-average molecular weight: 2000)

[0225] (Reaction initiator) Peroxide: (α,α'-di(t-butylperoxy)diisopropylbenzene, "Perbutyl P (PBP)" manufactured by NOF Corporation)

[0226] (Inorganic filler) Silica: Silica particles surface-treated with a silane coupling agent containing a methacryloyl group in the molecule (SC2500-SMJ manufactured by Admatex Co., Ltd.)

[0227] [Preparation Method] First, the components other than the inorganic filler were added to methyl ethyl ketone (MEK) in the composition (parts by mass) shown in Table 1, so that the solid content concentration was 40% by mass, and the mixture was mixed. The mixture was stirred for 60 minutes. Then, the inorganic filler was added to the obtained mixture in the composition (parts by mass) shown in Table 1, stirred for 60 minutes, and then dispersed using a bead mill. In this way, a varnish-like resin composition (varnish) with a solid content concentration of 55% was obtained. In the case of Comparative Example 1, since maleimide compound 2 did not dissolve, MEK was added when mixing the components other than the inorganic filler to prepare a mixture with a solid content concentration of 30%. Then, the inorganic filler was added and dispersed using a bead mill to obtain a varnish-like resin composition (varnish) with a solid content concentration of 46%.

[0228] Next, the prepreg was obtained as follows.

[0229] The obtained varnish was impregnated into a fibrous substrate (glass cloth: #2118 type, T-glass, #2118T S330 manufactured by Nitto Boseki Co., Ltd.), and then heated and dried at 120°C for 3 minutes to produce a prepreg. At that time, the content of the components constituting the resin in the prepreg (resin content) was adjusted to approximately 43% by mass. Furthermore, the thickness after curing was adjusted to 103 μm.

[0230] An evaluation substrate (metal-clad laminate) was obtained in the following manner.

[0231] Ten of the obtained prepregs were stacked together, and 12 μm thick copper foil (3EC-VLP manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on both sides. This was used as the pressure-bearing body, and it was heated to a temperature of 220°C at a heating rate of 3°C / min. By heating and pressurizing it at 220°C for 120 minutes under a pressure of 4 MPa, an evaluation substrate (metal-clad laminate) with a resin layer thickness of approximately 1 mm (1030 μm) was obtained, with copper foil bonded to both sides.

[0232] The prepreg and evaluation substrate prepared as described above were evaluated using the method shown below.

[0233] [Glass Transition Temperature (Tg)] A resin cured product obtained by etching away the metal foil (copper foil) from the evaluation substrate (metal-clad laminate) was used as a test specimen, and the glass transition temperature Tg of the cured resin composition was measured using a viscoelastic spectrometer "DMS6100" manufactured by Seiko Instruments Inc. At this time, dynamic viscoelasticity measurement (DMA) was performed with a bending module at a frequency of 10 Hz, and the temperature at which tanδ showed a maximum when the temperature was raised from room temperature to 400°C under the condition of a heating rate of 5°C / min was defined as the glass transition temperature Tg (°C). If the measured glass transition temperature was 250°C or higher, it was judged to be "pass".

[0234] [Thermal Expansion Coefficient] A resin-cured product obtained by etching off the copper foil from the evaluation substrate (metal-clad laminate) was used as a test specimen. The thermal expansion coefficient of the evaluation substrate in the planar direction (Y direction) at a temperature below the glass transition temperature of the cured resin composition was measured by the TMA method (Thermo-mechanical analysis). Specifically, a TMA device (TMA6000 manufactured by SII Nanotechnology Co., Ltd.) was used for the measurement in compression mode. To eliminate the effect of thermal strain on the test specimen, a load of 10 g was applied to the test specimen, and it was heated from 20°C to 320°C at a heating rate of 10°C / min, and then cooled to room temperature. After that, with a load of 10 g applied to the test specimen, it was heated from 20°C to 320°C at a heating rate of 10°C / min. A temperature displacement chart was obtained during this heating. The average thermal expansion coefficient from 50 to 100°C was calculated from the temperature displacement chart obtained at this time. A smaller coefficient of thermal expansion (CTE) indicates a more favorable result, and a value of 7.1 ppm / °C or less was considered "acceptable."

[0235] [Varnish Stability] After storing the varnish prepared under the above conditions at 25°C for 48 hours, it was visually inspected. If no precipitate was found, it was evaluated as "good," and if precipitate was found, it was evaluated as "poor." In Comparative Example 1, precipitate was found, which is thought to be maleimide compound 2.

[0236] [Water Absorption Rate] A resin-cured material obtained by etching off the copper foil from the evaluation substrate (metal-clad laminate) was used as a test specimen, and the water absorption rate (%) was measured according to the method in accordance with IPC TM-650 2.6.2.1. If the water absorption rate was 0.30% or less, it was judged to be "pass".

[0237] The results for each of the above evaluations are shown in Table 1.

[0238]

[0239] Table 1 shows that when polymaleimide resin (A) and benzoxazine compound (B) are included (Examples 1-6), a cured product with a high glass transition temperature and low thermal expansion coefficient and water absorption is obtained. Furthermore, Examples 1-6 were found to have excellent varnish stability. Specifically, compared to the case where polymaleimide resin (A) is not included, and maleimide compound 2 (3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide) is included as a maleimide compound other than polymaleimide resin (A) (Comparative Example 1), Examples 1-6 yielded a cured product with lower water absorption and superior varnish stability. Furthermore, it was found that in Examples 1 to 6, cured products with a higher glass transition temperature and lower thermal expansion coefficient were obtained compared to the case in which maleimide compound 3 (a maleimide compound having an indan structure and an arylene structure oriented and bonded at the meta position in the molecule) was included as a maleimide compound other than polymaleimide resin (A) without containing polymaleimide resin (A) (Comparative Example 2). Furthermore, it was found that in Examples 1 to 6, cured products with a lower thermal expansion coefficient were obtained compared to the case in which modified PPE was included (Comparative Example 3) without containing benzoxazine compound (B). It was found that in the cases where maleimide compound 1 or maleimide compound 2 was included in addition to polymaleimide resin (A) and benzoxazine compound (B) (Examples 2, 3, and 5), the resulting cured products had an even higher glass transition temperature and a lower thermal expansion coefficient. Furthermore, it was found that in the case where maleimide compound 6 was included in addition to polymaleimide resin (A) and benzoxazine compound (B) (Example 6), the resulting cured product had a lower water absorption rate. Furthermore, it was found that when a high molecular weight material (D) was included in addition to the polymaleimide resin (A) and benzoxazine compound (B) (Examples 4 and 5), the resulting cured product had a lower thermal expansion coefficient. In addition, when a maleimide compound (C) and a high molecular weight material (D) were included in addition to the polymaleimide resin (A) and benzoxazine compound (B) (Example 5), it was found that the resulting cured product had a higher glass transition temperature and a lower thermal expansion coefficient.Therefore, it was found that it is preferable to contain not only the polymaleimide resin (A) and the benzoxazine compound (B), but also a maleimide compound (C) or a high molecular weight compound (D), and it is even more preferable to contain both the maleimide compound (C) and the high molecular weight compound (D).

[0240] This application is based on Japanese Patent Application No. 2025-056144, filed on 28 March 2025, the contents of which are included in this application.

[0241] Although the present invention has been adequately and sufficiently described above through embodiments, those skilled in the art should recognize that it is easy to modify and / or improve upon the above embodiments. Therefore, unless such modifications or improvements implemented by those skilled in the art fall outside the scope of the claims, such modifications or improvements shall be considered to be included within the scope of the claims.

[0242] The present invention provides a resin composition that yields a cured product with a high glass transition temperature and low thermal expansion coefficient and water absorption rate. Furthermore, the present invention provides a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that can be obtained using the resin composition.

Claims

1. A resin composition comprising: a polymaleimide resin (A) having a partial structure represented by the following general formula (1), a partial structure represented by general formula (T-1) chemically bonded to the partial structure represented by general formula (1), and a partial structure represented by general formula (T-2) chemically bonded to the partial structure represented by general formula (1); and a benzoxazine compound (B). [In the above general formula (1), R １３ each independently represent an alkyl group having 1 to 18 carbon atoms, m ２ represents an integer of 0 to 4, n １ represents an average number of repeating units, two * each represent a bond, one bond is at L １３ or L １４ in the following general formula (T-1) and is chemically bonded at that position, and the other bond is at L １１ or L １２ in the following general formula (T-2) and is chemically bonded at that position.]] [In the above general formula (T-1) or (T-2), R １１ and R １５ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, R １２ and R １４ each independently represent a hydrocarbon group having 1 to 18 carbon atoms, L １１ to L １４ each independently represent a bond or a hydrogen atom, provided that it is chemically bonded to the partial structure represented by general formula (1) at the position of L １１ or L １２ , and is chemically bonded to the partial structure represented by general formula (1) at the position of L １３ or L １４ , and L １１ to L １４ that are not chemically bonded to the partial structure represented by general formula (1) are hydrogen atoms, and m １ and m ３ each represent 2.]] 2. The resin composition according to claim 1, wherein the benzoxazine compound (B) comprises a benzoxazine compound having an allyl group in its molecule.

3. The resin composition according to claim 1, further comprising a maleimide compound (C) different from the polymaleimide resin (A), having a maleimide equivalent of 500 g / mol or less.

4. The resin composition according to claim 1, further comprising a high molecular weight material (D) having a number average molecular weight of 10,000 or more and 1,500,000 or less.

5. The resin composition according to claim 4, wherein the high molecular weight material (D) comprises at least one of (meth)acrylic resin and styrene copolymer.

6. The resin composition according to claim 5, wherein the high molecular weight material (D) comprises a (meth)acrylic resin.

7. The resin composition according to claim 4, wherein the content of the high molecular weight material (D) is 40% by mass or less with respect to the total mass of the polymaleimide resin (A), the benzoxazine compound (B), and the high molecular weight material (D).

8. The resin composition according to claim 3, further comprising a high molecular weight material (D) having a number average molecular weight of 10,000 or more and 1,500,000 or less.

9. The resin composition according to claim 8, wherein the content of the high molecular weight material (D) is 40% by mass or less with respect to the total mass of the polymaleimide resin (A), the benzoxazine compound (B), the maleimide compound (C), and the high molecular weight material (D).

10. A prepreg comprising a resin composition according to any one of claims 1 to 9 or a semi-cured product of the resin composition, and a fibrous substrate.

11. A resin-coated film comprising a resin layer containing the resin composition described in any one of claims 1 to 9 or a semi-cured product of the resin composition, and a support film.

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

13. A metal-clad laminate comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 9, and a metal foil.

14. A metal-clad laminate comprising an insulating layer containing a cured prepreg according to claim 10, and a metal foil.

15. A wiring board comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 9, and wiring.

16. A wiring board comprising an insulating layer containing a cured prepreg according to claim 10, and wiring.

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