Resin composition, resin film, prepreg and metal-clad laminate

Abstract

To provide a resin composition having excellent dielectric loss tangent and peeling strength from a copper foil having low roughness.SOLUTION: There is provided a resin composition comprising (A) a polyphenylene ether, (B) a bis(vinylphenyl)ethane and (C) an organic peroxide, wherein the polyphenylene ether (A) contains a repeating unit derived from a phenol of the following formula (1) and a repeating unit derived from a phenol of the following formula (2).SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] With the remarkable progress in information network technology and the expansion of services utilizing information networks, electronic devices are being required to handle larger amounts of information and to process faster. To meet these demands, printed wiring boards mounted on electronic devices are being strongly required to reduce signal transmission loss in addition to the traditional properties required, such as insulation reliability, heat resistance, flame retardancy, and copper foil peel strength.

[0003] To improve transmission loss, it is effective to reduce the dielectric loss tangent of the insulating layer of a printed wiring board. Therefore, polyphenylene ether (PPE) compositions, which have good dielectric properties and high heat resistance, are preferably used as materials for the above-mentioned printed wiring boards.

[0004] In addition, reducing the roughness of the copper foil used in the conductor layer is also effective in reducing transmission loss in printed wiring boards. However, using copper foil with a low roughness reduces the adhesive strength between the resin and the copper foil, which poses a problem.

[0005] Furthermore, in recent years, advances in high-frequency technologies, such as 5G, have led to a demand for materials with superior dielectric properties. For example, Patent Document 1 discloses a resin composition containing a curable polyvinylbenzyl ether compound and a modified styrene-based elastomer, which exhibits excellent dielectric loss tangent and copper foil peel strength. Patent Document 2 discloses a resin composition with excellent dielectric loss tangent, which contains a vinyl group-containing PPE, bis(vinylphenyl)ethane, and a modified divinylbenzene. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-51226 [Patent Document 2] U.S. Patent No. 11111383 Summary of the Invention [Problem to be solved by the invention]

[0007] However, although Patent Document 1 shows the copper foil peel strength when a copper foil with Rz=2.3 μm is used, and Patent Document 2 shows the copper foil peel strength when a finely roughened foil (HVLP) is used, there were further issues regarding adhesion to copper foil with a lower roughness (for example, copper foil with Rz<1.0 μm).

[0008] The present invention has been made in view of the above problems, and aims to provide a resin composition that is excellent in dielectric tangent and peel strength from a low-roughness copper foil. Another aim of the present invention is to provide a resin film, a prepreg, and a metal-clad laminate formed using the resin composition. [Means for solving the problem]

[0009] That is, the present invention is as follows. [1] A resin composition comprising (A) polyphenylene ether, (B) bis(vinylphenyl)ethane, and (C) an organic peroxide, (A) The polyphenylene ether contains a repeating unit derived from a phenol represented by the following formula (1) and a repeating unit derived from a phenol represented by the following formula (2), [ka] (In formula (1), R 11 each independently represents an optionally substituted saturated hydrocarbon group having 1 to 6 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, or a halogen atom; R 12 are each independently a hydrogen atom, an optionally substituted hydrocarbon group having 1 to 6 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, or a halogen atom. [ka] (In formula (2), R 22 are each independently a hydrogen atom, an optionally substituted saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, or a halogen atom, and two R 22 are not both hydrogen atoms, and R 21 is a partial structure represented by the following formula (3). [ka] In formula (3), R 31 are each independently an optionally substituted linear alkyl group having 1 to 8 carbon atoms, or two R 31 is a cyclic alkyl structure having 1 to 8 carbon atoms to which R 32 each independently represents an optionally substituted alkylene group having 1 to 8 carbon atoms; each b independently represents 0 or 1; R 33 is a hydrogen atom, an optionally substituted alkyl group having 1 to 8 carbon atoms, or an optionally substituted phenyl group. The (A) polyphenylene ether contains 55 mol % or more and 95 mol % or less of repeating units derived from a phenol of the formula (1) and 5 mol % or more and 45 mol % or less of repeating units derived from a phenol of the formula (2), relative to a total of 100 mol % of repeating units derived from a phenol of the formula (1) and repeating units derived from a phenol of the formula (2), A resin composition, characterized in that the mass ratio of the (A) polyphenylene ether to the (B) bis(vinylphenyl)ethane is 30:70 to 70:30. [2] The resin composition according to [1], wherein the partial structure represented by the formula (3) is a t-butyl group. [3] The resin composition according to [1] or [2], characterized in that the polyphenylene ether has a reduced viscosity (ηsp / c) of 0.03 to 0.30 dL / g as measured in a chloroform solution having a concentration of 0.5 g / dL at 30°C. [4] The resin composition according to any one of [1] to [3], wherein the (B) bis(vinylphenyl)ethane is 1,2-bis(4-vinylphenyl)ethane. [5] A prepreg, characterized by being a composite of a substrate and the resin composition according to any one of [1] to [4]. [6] The prepreg according to [5], characterized in that the substrate is glass cloth. [7] A metal-clad laminate, characterized by being a laminate of a cured product of the prepreg according to [5] or [6] and a metal foil. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a polyphenylene ether resin composition that is excellent in dielectric loss tangent and peel strength from a copper foil with a low roughness. The present invention also provides an electronic circuit board material, a resin film, a prepreg, and a metal-clad laminate formed using the polyphenylene ether resin composition. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The following present embodiment is an example for explaining the present invention, and the present invention is not limited to only this present embodiment, and the present invention can be carried out by appropriately modifying it within the scope of its gist.

[0012] In the present embodiment, polyphenylene ether in which some or all of the hydroxyl groups contained in the polyphenylene ether have been modified may be simply referred to as “polyphenylene ether.” Therefore, when the term “polyphenylene ether” is used, it includes both unmodified polyphenylene ether and modified polyphenylene ether, unless otherwise specified.

[0013] In this specification, A (numeric value) to B (numeric value) mean A or more and B or less. In addition, in this specification, the term "substituent" refers to, for example, a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a halogen atom, etc.

[0014] <Resin composition> The resin composition of the present embodiment is a resin composition containing (A) polyphenylene ether, (B) bis(vinylphenyl)ethane, and (C) an organic peroxide.

[0015] (Polyphenylene ether) The polyphenylene ether contains at least a repeating unit derived from a phenol of the following formula (1) and a repeating unit derived from a phenol of the following formula (2), or may consist solely of a repeating unit derived from a phenol of the following formula (1) and a repeating unit derived from a phenol of the following formula (2). [ka] (In formula (1), R 11 are each independently an optionally substituted saturated hydrocarbon group having 1 to 6 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, or a halogen atom; R 12 are each independently a hydrogen atom, an optionally substituted hydrocarbon group having 1 to 6 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, or a halogen atom. [ka] In formula (2), R 22 are each independently a hydrogen atom, an optionally substituted saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, or a halogen atom, and two R 22 is not both hydrogen atoms, and R 21 is a partial structure represented by the following formula (3): [ka] In formula (3), R31 are each independently an optionally substituted linear alkyl group having 1 to 8 carbon atoms, or two R 31 is a cyclic alkyl structure having 1 to 8 carbon atoms to which R 32 are each independently an optionally substituted alkylene group having 1 to 8 carbon atoms, each b is independently 0 or 1, and R 33 is a hydrogen atom, an optionally substituted alkyl group having 1 to 8 carbon atoms, or an optionally substituted phenyl group.

[0016] In the above formula (1), R 11 are each independently preferably a saturated hydrocarbon group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, more preferably a methyl group or a phenyl group, and even more preferably a methyl group. 11 Preferably, both have the same structure.

[0017] In the above formula (1), R 12 are each independently preferably a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, more preferably a hydrogen atom or a methyl group.

[0018] In the above formula (2), R 22 are each independently preferably a hydrogen atom, a saturated or unsaturated hydrocarbon group having 1 to 15 carbon atoms, or an aryl group having 6 to 12 carbon atoms which may be substituted with an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms which may be substituted with an alkyl group having 1 to 6 carbon atoms, and even more preferably a hydrogen atom or a methyl group. 22 are preferably different, and it is more preferable that one is a hydrogen atom and the other is a hydrocarbon group having 1 to 6 carbon atoms (preferably a methyl group).

[0019] The partial structure represented by the above formula (3) is preferably a group containing a secondary and / or tertiary carbon, such as an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a tert-amyl group, a 2,2-dimethylpropyl group, a cyclohexyl group, or a structure having a phenyl group at the end of any of these groups, more preferably a tert-butyl group or a cyclohexyl group, and even more preferably a tert-butyl group.

[0020] In this embodiment, the structure of the polyphenylene ether can be identified by analyzing the polyphenylene ether using techniques such as NMR and mass spectrometry. A specific method for identifying the structure of the polyphenylene ether is to perform field desorption mass spectrometry (FD-MS), which is known to be less prone to fragmentation, and estimate the repeating units based on the intervals between detected ions. Furthermore, the structure of the polyphenylene ether can be estimated by combining peak analysis of fragment ions using electron ionization (EI) and structural analysis by NMR.

[0021] In this embodiment, the polyphenylene ether has a content of repeating units derived from phenol of the above formula (1) of 55 mol% or more and 95 mol% or less, and a content of repeating units derived from phenol of the following formula (2) of 5 mol% or more and 45 mol% or less, relative to a total of 100 mol% of repeating units of the above formula (1) and formula (2). The polyphenylene ether contains the repeating unit derived from the phenol of the formula (1) and the repeating unit derived from the phenol of the formula (2) in the above ratio, and in addition to having excellent dielectric properties, the copper foil peel strength of the copper-clad laminate is improved.

[0022] From a similar viewpoint, the polyphenylene ether preferably has a content of repeating units derived from phenol of formula (1) of 60 mol% to 90 mol% and a content of repeating units derived from phenol of formula (2) of 10 mol% to 40 mol%, based on the total of 100 mol% of repeating units of formula (1) and formula (2). It is more preferable that the content of repeating units derived from phenol of formula (1) is 70 mol% to 85 mol% and the content of repeating units derived from phenol of formula (2) is 15 mol% to 30 mol%. It is even more preferable that the content of repeating units derived from phenol of formula (1) is 80 mol% to 85 mol% and the content of repeating units derived from phenol of formula (2) is 15 mol% to 20 mol%.

[0023] Since the phenol of the above formula (1) does not have any unsubstituted ortho-positions (i.e., no hydrogen atoms are bonded to the carbon atoms in the two ortho-positions to the carbon atom to which the hydroxyl group is bonded), it can react with another phenolic monomer only at the carbon atom in the para-position to the phenolic hydroxyl group. Therefore, the repeating unit derived from the above formula (1) includes a repeating unit having the structure of the following formula (4): [ka] (In formula (4), R 11 and R 12 is the same as equation (1).

[0024] In addition to the phenolic hydroxyl group, the phenol of formula (2) can react with another phenolic monomer at either the ortho- or para-position of the phenol. Thus, the repeating unit derived from the phenol of formula (2) has the structure of formula (5), formula (6), or a combination thereof: [ka] [ka] (R in Equation (5) and Equation (6) 21 , R 22 is the same as equation (2).

[0025] The polyphenylene ether may also contain a structural unit derived from phenol represented by the following formula (7): [ka] (In formula (7), X is an arbitrary linking group having a valence of a, a is an integer of 2 to 6, and R 4 is either a linear alkyl group having 1 to 8 carbon atoms or a partial structure represented by the formula (3) above, and is bonded to at least one of the carbon atoms at the 2nd or 6th position, with the carbon atom of the benzene ring to which -O- is bonded being the 1st position, and each k is independently an integer of 1 to 4.

[0026] In the above formula (7), R 4 are each independently either a linear alkyl group having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, or an n-propyl group, or a partial structure represented by the above formula (3), and are preferably a methyl group or a structure represented by the above formula (3). The a partial structures may be the same or different. In particular, from the viewpoint of obtaining a polyphenylene ether having better solubility in solvents and a higher glass transition temperature after curing, it is preferable that the a partial structures are the same.

[0027] In the above formula (7), k is an integer of 1 to 4, and preferably an integer of 2 to 4.

[0028] In addition, in the above formula (7), R 4 is bonded to at least one of the carbon atoms at the 2nd and 6th positions, with the carbon atom of the benzene ring to which -O- is bonded being the 1st position, and R 4 When R is a linear alkyl group having 1 to 8 carbon atoms, it is preferably bonded to both the 2-position and the 6-position. 4is a partial structure represented by formula (3), it is preferably bonded to only one of the 2-position and the 6-position.

[0029] The polyphenylene ether may contain a repeating unit derived from the above formula (7), as well as a repeating unit derived from a phenol of the above formula (1) and / or a repeating unit derived from a phenol of the above formula (2). In this case, R in the above formula (2) 21 and R in the above formula (7) 4 are both partial structures (functional groups) represented by formula (3) (when the partial structures (functional groups) represented by formula (3) are substituted on both the phenol compound represented by formula (2) and the phenol compound represented by formula (7)), the structures of the partial structures (functional groups) represented by formula (3) may be the same or different.

[0030] Furthermore, in the above formula (7), X is any a-valent linking group, and is not particularly limited, but examples thereof include hydrocarbon groups such as chain hydrocarbons and cyclic hydrocarbons; hydrocarbon groups containing one or more atoms selected from nitrogen, phosphorus, silicon, and oxygen; atoms such as nitrogen, phosphorus, and silicon; or groups combining these. X may be a linking group other than a single bond. X may be a linking group that links a partial structures to each other.

[0031] The above X is R 4 is bonded to the benzene ring, through a valent alkyl skeleton, a single bond, an ester bond, etc., 4 R is bonded to a benzene ring via a-valent aryl skeleton, a single bond, an ester bond, or the like. 4 Examples of the heterocyclic skeleton include an a-valent heterocyclic skeleton bonded to a benzene ring to which is bonded.

[0032] Here, the alkyl skeleton is not particularly limited, but examples thereof include a skeleton in which the branched ends of a chain hydrocarbon (e.g., a chain saturated hydrocarbon) having 2 to 6 carbon atoms and branched to at least a number of positions are directly bonded to a benzene ring in a partial structure (as long as a benzene ring is bonded to the a branched ends, there may be a branched end to which no benzene ring is bonded). Furthermore, the aryl skeleton is not particularly limited, but examples thereof include a skeleton in which a benzene ring, a mesitylene group, or a 2-hydroxy-5-methyl-1,3-phenylene group is bonded to R via a single bond or an alkyl chain. 4 Furthermore, the heterocyclic skeleton is not particularly limited, but examples thereof include a skeleton in which a triazine ring is bonded to a benzene ring to which R is bonded via a single bond or an alkyl chain. 4 Examples of such a skeleton include a skeleton bonded to a benzene ring to which

[0033] In the above formula (7), a is an integer of 2 to 6, and preferably an integer of 2 to 4.

[0034] When the phenol of formula (7) does not have an unsubstituted ortho position, the structural unit derived from the phenol of formula (7) has a structure of the following formula (8), and when the phenol of formula (7) has an unsubstituted ortho position, the structural unit derived from the phenol of formula (7) has a structure of the following formula (8), a structure of the following formula (9), or a combination thereof. [ka] [ka] (R in Equation (8) and Equation (9) 4 is the same as equation (7).

[0035] The polyphenylene ether in this embodiment may have at least one partial structure selected from the group consisting of the following formulas (10), (11), (12), and (13). [ka] [ka] [ka] In formula (12), R 6 is a hydrogen atom or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and the saturated or unsaturated hydrocarbon is R 6 may have a substituent within the range of 1 to 10 carbon atoms in total.) [ka] (In formula (13), R 7 is a saturated or unsaturated divalent hydrocarbon group having 1 to 10 carbon atoms, and the saturated or unsaturated divalent hydrocarbon is R 7 may have a substituent within a range of 1 to 10 carbon atoms in total, and R 8 is a hydrogen atom or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and the saturated or unsaturated hydrocarbon is R 8 may have a substituent within a range of 1 to 10 different total carbon atoms.) The partial structure represented by at least one selected from the group consisting of the above formula (10), formula (11), formula (12), and formula (13) may be directly bonded to a hydroxyl group contained in the polyphenylene ether.

[0036] The polyphenylene ether preferably has a reduced viscosity (ηsp / c) of 0.03 to 0.30 dL / g, more preferably 0.05 to 0.30 dL / g, and even more preferably 0.07 to 0.30 dL / g, as measured in a chloroform solution having a concentration of 0.5 g / dL at 30°C. The reduced viscosity can be measured by the method described in the Examples below.

[0037] (Production method of polyphenylene ether) The polyphenylene ether can be obtained, for example, by a method including at least a step of oxidative polymerization of monohydric phenol compounds represented by the above formulas (1) and (2), or oxidative polymerization of monohydric and polyhydric phenol compounds represented by the above formulas (1), (2), and (7). In the step of carrying out the oxidative polymerization, it is preferable to oxidatively polymerize a raw material containing at least the phenol of the formula (1) and the phenol of the formula (2), or the phenol of the formula (1), the phenol of the formula (2), and the phenol of the formula (7).

[0038] Examples of the monohydric phenol compound represented by the above formula (1) include 2,6-dimethylphenol, 2-methyl-6-ethylphenol, 2,6-diethylphenol, 2-ethyl-6-n-propylphenol, 2-methyl-6-chlorophenol, 2-methyl-6-bromophenol, 2-methyl-6-n-propylphenol, 2-ethyl-6-bromophenol, 2-methyl-6-n-butylphenol, 2,6-di-n-propylphenol, 2-ethyl-6-chlorophenol, 2-methyl-6-phenylphenol, 2,6-diphenylphenol, 2-methyl-6-tolylphenol, 2,6-ditolylphenol, 2,3,6-trimethylphenol, 2,3-diethyl-6-n-propylphenol, 2,3,6-tributylphenol, 2,6-di-n-butyl-3-methylphenol, 2,6-dimethyl-3-n-butylphenol, and 2,6-dimethyl-3-t-butylphenol. Among these, 2,6-dimethylphenol, 2,3,6-trimethylphenol, and 2,6-diphenylphenol are particularly preferred because they are inexpensive and easily available. The monohydric phenol compound represented by the above formula (1) may be used singly or in combination of two or more kinds.

[0039] Examples of the monohydric phenol compound represented by the above formula (2) include 2-isopropyl-5-methylphenol, 2-cyclohexyl-5-methylphenol, 2-tert-butyl-5-methylphenol, 2-isobutyl-5-methylphenol, etc. From the viewpoint of suppressing multi-branching and gelation, 2-t-butyl-5-methylphenol and 2-cyclohexyl-5-methylphenol, which have bulky substituents, are more preferred. The monohydric phenol compounds represented by the above formula (2) may be used singly or in combination of two or more kinds.

[0040] Among the polyhydric phenol compounds represented by the above formula (7), examples of phenol compounds having two phenol units in the molecule include 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4,4'-methylenebis(2,6-dimethylphenol), bis(4-hydroxy-3-methylphenyl)sulfide, bis(4-hydroxy-3,5-dimethylphenyl)sulfone, α,α'-bis(4-hydroxy-3,5-dimethylphenyl)-1,4-diisopropylbenzene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, and 1,1-bis(2-methyl-4-hydroxy-5-t-butylphenyl)butane. Among these, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane and 1,1-bis(2-methyl-4-hydroxy-5-t-butylphenyl)butane are particularly preferred because they are inexpensive and easily available.

[0041] Furthermore, among the polyhydric phenol compounds represented by the above formula (7), examples of phenol compounds having three or more phenol units in the molecule include 4,4'-[(3-hydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(3-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 4,4'-[(4-hydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(4-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 4,4'-[( 2-hydroxy-3-methoxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(4-hydroxy-3-ethoxyphenyl)methylene]bis(2,3,6-trimethylethylphenol), 4,4'-[(3,4-dihydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(3,4-dihydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 2,2'-[(4-hydroxyphenyl)methylene]bis(3,5,6-trimethylphenol), 4,4'-[4-(4-hydroxyphenyl)methylene]bis(4-hydroxyphenyl)methylene]bis(3,5,6-trimethylphenol), 4,4'-[(2-hydroxyphenyl)methylene]-bis(2,3,6-trimethylphenol), 4,4'-[1-[4-[1-(4-hydroxy-3,5-dimethylphenyl)-1-methylethyl]phenyl]ethylidene]bis(2,6-dimethylphenol), 4,4'-[1-[4-[1-(4-hydroxy-3-fluorophenyl)-1-methylethyl]phenyl]ethylidene]bis(2,6-dimethylphenol), 2,6-bis[(4-hydroxy-3,5-dimethylphenyl) 2,6-bis[(4-hydroxy-2,3,6-trimethylphenyl)methyl]-4-methylphenol, 2,6-bis[(4-hydroxy-3,5,6-trimethylphenyl)methyl]-4-ethylphenol, 2,4-bis[(4-hydroxy-3-methylphenyl)methyl]-6-methylphenol, 2,6-bis[(4-hydroxy-3-methylphenyl)methyl]-4-methylphenol, 2,4-bis[(4-hydroxy-3-cyclohexylphenyl)methyl]-6-methylphenol, 2,4-bis[(4-hydroxy-3-methylphenyl)methyl]-6-cyclohexylphenol, 2,4-bis[(2-hydroxy-5-methylphenyl)methyl]-6-cyclohexylphenol, 2,4-bis[(4-hydroxy-2,3,6-trimethylphenyl)methyl]-6-cyclohexylphenol, 3,6-bis[(4-hydroxy-3,5-dimethylphenyl)methyl]-1,2-benzenediol, 4,6-bis[(4-hydroxy-3,5-dimethylphenyl)methyl]-1,3-benzenediol, 2,4,6 -Tris[(4-hydroxy-3,5-dimethylphenyl)methyl]-1,3-benzenediol, 2,4,6-tris[(2-hydroxy-3,5-dimethylphenyl)methyl]-1,3-benzenediol, 2,2'-methylenebis[6-[(4 / 2-hydroxy-2,5 / 3,6-dimethylphenyl)methyl]-4-methylphenol], 2,2'-methylenebis[6-[(4-hydroxy-3,5-dimethylphenyl)methyl]-4-methylphenol], 2,2'-methylenebis[6-[(4 / 2-hydroxy-2,3,5 / 3 ,4,6-trimethylphenyl)methyl]-4-methylphenol], 2,2'-methylenebis[6-[(4-hydroxy-2,3,5-trimethylphenyl)methyl]-4-methylphenol], 4,4'-methylenebis[2-[(2,4-dihydroxyphenyl)methyl]-6-methylphenol], 4,4'-methylenebis[2-[(2,4-dihydroxyphenyl)methyl]-3,6-dimethylphenol], 4,4'-methylenebis[2-[(2,4-dihydroxy-3-methylphenyl)methyl]-3,6-dimethylphenol] ol], 4,4'-methylenebis[2-[(2,3,4-trihydroxyphenyl)methyl]-3,6-dimethylphenol], 6,6'-methylenebis[4-[(4-hydroxy-3,5-dimethylphenyl)methyl]-1,2,3-benzenetriol], 4,4'-cyclohexylidenebis[2-cyclohexyl-6-[(2-hydroxy-5-methylphenyl)methyl]phenol], 4,4'-cyclohexylidenebis[2-cyclohexyl-6-[(4-hydroxy-3,5-dimethylphenyl)methyl]phenol], 4,Examples include 4'-cyclohexylidenebis[2-cyclohexyl-6-[(4-hydroxy-2-methyl-5-cyclohexylphenyl)methyl]phenol], 4,4'-cyclohexylidenebis[2-cyclohexyl-6-[(2,3,4-trihydroxyphenyl)methyl]phenol], 4,4',4'',4'''-(1,2-ethanediylidene)tetrakis(2,6-dimethylphenol), 4,4',4'',4'''-(1,4-phenylenedimethylidene)tetrakis(2,6-dimethylphenol), and 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane. Among these, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane is particularly preferred because it is inexpensive and easily available. The polyhydric phenol compounds represented by the above formula (7) may be used singly or in combination of two or more kinds.

[0042] The number of phenolic hydroxyl groups in the polyhydric phenol compound represented by the above formula (7) is not particularly limited as long as it is 2 to 6, but is preferably 2 to 4 from the viewpoint of easier control of the thermal curing rate.

[0043] Normally, the oxidative polymerization of phenols that have hydrogen atoms at the ortho position (e.g., 2-methylphenol, 2,5-dimethylphenol, 2-phenylphenol) can also form ether bonds at the ortho position, making it difficult to control the bonding position of the phenol compound during oxidative polymerization. As a result, a high-molecular-weight polymer is obtained that is polymerized in a branched manner with an average of 3.5 or more hydroxyl groups per molecule, ultimately resulting in the formation of a gel component that is insoluble in solvents.

[0044] On the other hand, when a bulky substituent is present at one ortho position of the phenol represented by the above formula (2), it becomes possible to control the bonding position of the phenol compound during oxidative polymerization, even though a hydrogen atom is present at the ortho position on the opposite side, and a polyphenylene ether having an average of less than 3.0 hydroxyl groups per molecule can be obtained.

[0045] Furthermore, when the phenol represented by the above formula (2) has a bulky substituent at one of the ortho positions, even when a monohydric phenol having a non-bulky substituent (e.g., a hydrogen atom, an allyl group, a methyl group, an ethyl group, a methoxy group, etc.) at the ortho position of the oxygen atom of the phenol is used as the third component, gelation does not occur, and a polyphenylene ether having an average of less than 3.0 hydroxyl groups per molecule can be obtained.

[0046] The molecular weight of the polyphenylene ether can be adjusted, for example, by the molar ratio of the structure of formula (2) to the total of the structure of formula (1) and the structure of formula (2), or by the molar ratio of the structure of formula (7) to the total of the structure of formula (1) and the structure of formula (7). That is, when the molar ratio of the structure of formula (2) or formula (7) is high, the achieved molecular weight (reduced viscosity) can be lowered, and when the molar ratio of the structure of formula (2) or formula (7) is low, the molecular weight (reduced viscosity) can be adjusted to be high.

[0047] In the method for producing polyphenylene ether, an aromatic solvent that is a good solvent for polyphenylene ether can be used as the polymerization solvent in the oxidative polymerization step.

[0048] A good solvent for polyphenylene ether is a solvent that can dissolve polyphenylene ether, and examples of such solvents include aromatic hydrocarbons such as benzene, toluene, xylene (including o-, m-, and p-isomers), and ethylbenzene; halogenated hydrocarbons such as chlorobenzene and dichlorobenzene; and nitro compounds such as nitrobenzene.

[0049] The polymerization catalyst used can be a known catalyst system that can generally be used for producing polyphenylene ether. Commonly known catalyst systems include those consisting of a transition metal ion having oxidation-reduction ability and an amine compound capable of forming a complex with the transition metal ion, such as a catalyst system consisting of a copper compound and an amine compound, a catalyst system consisting of a manganese compound and an amine compound, or a catalyst system consisting of a cobalt compound and an amine compound. Since the polymerization reaction proceeds efficiently under slightly alkaline conditions, a small amount of alkali or an additional amine compound may be added thereto.

[0050] A polymerization catalyst that is preferably used is a catalyst comprising a copper compound, a halogen compound, and an amine compound as catalyst components, and more preferably a catalyst containing a diamine compound represented by the following formula (14) as the amine compound: [ka] (In formula (14), R 14 , R 15 , R 16 , R 17 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, provided that all of them are not hydrogen atoms at the same time. 18 is a linear or methyl-branched alkylene group having 2 to 5 carbon atoms.

[0051] Examples of copper compounds for the catalyst components described herein are listed below. Suitable copper compounds include cuprous compounds, cupric compounds, and mixtures thereof. Examples of cupric compounds include cupric chloride, cupric bromide, cupric sulfate, and cupric nitrate. Examples of cuprous compounds include cuprous chloride, cuprous bromide, cuprous sulfate, and cuprous nitrate. Among these, particularly preferred metal compounds are cuprous chloride, cupric chloride, cuprous bromide, and cupric bromide. These copper salts may also be synthesized immediately upon use from an oxide (e.g., cuprous oxide), carbonate, hydroxide, or the like and the corresponding halogen or acid. A frequently used method is to mix the cuprous oxide exemplified above with a hydrogen halide (or a solution of a hydrogen halide).

[0052] Examples of the halogen compounds include hydrogen chloride, hydrogen bromide, hydrogen iodide, sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium chloride, tetraethylammonium bromide, and tetraethylammonium iodide. These compounds can be used as aqueous solutions or solutions using appropriate solvents. These halogen compounds can be used alone or in combination of two or more. Preferred halogen compounds are aqueous solutions of hydrogen chloride and hydrogen bromide.

[0053] The amount of these compounds used is not particularly limited, but is preferably 2 to 20 times the molar amount of halogen atoms relative to the molar amount of copper atoms, and the preferred amount of copper atoms used is in the range of 0.02 to 0.6 moles per 100 moles of the phenol compound added to the polymerization reaction.

[0054] Examples of the diamine compound of the catalyst component include N,N,N',N'-tetramethylethylenediamine, N,N,N'-trimethylethylenediamine, N,N'-dimethylethylenediamine, N,N-dimethylethylenediamine, N-methylethylenediamine, N,N,N',N'-tetraethylethylenediamine, N,N,N'-triethylethylenediamine, N,N'-diethylethylenediamine, N,N-diethylethylenediamine, N-ethylethylenediamine, N,N-dimethyl-N'-ethylethylenediamine, N,N'-dimethyl-N-ethylethylenediamine, Nn-propylethylenediamine, N,N'-n-propylethylenediamine, Ni-propylethylenediamine, N,N'-i-propylethylenediamine, Nn -butylethylenediamine, N,N'-n-butylethylenediamine, Ni-butylethylenediamine, N,N'-i-butylethylenediamine, Nt-butylethylenediamine, N,N'-t-butylethylenediamine, N,N,N',N'-tetramethyl-1,3-diaminopropane, N,N,N'-trimethyl-1,3-diaminopropane, N,N'-dimethyl-1,3-diaminopropane, N-methyl-1,3-diaminopropane, N,N,N',N'-tetramethyl-1,3-diamino-1-methylpropane, N,N,N',N'-tetramethyl-1,3-diamino-2-methylpropane, N,N,N',N'-tetramethyl-1,4-diaminobutane, and N,N,N',N'-tetramethyl-1,5-diaminopentane. A preferred diamine compound for this embodiment is one in which the number of carbon atoms in the alkylene group connecting the two nitrogen atoms is 2 or 3. The amount of these diamine compounds used is not particularly limited, but is preferably in the range of 0.01 mol to 10 mol per 100 mol of the phenol compound added to the polymerization reaction.

[0055] The polymerization catalyst may contain primary amines and secondary monoamines as components thereof. Examples of secondary monoamines include, but are not limited to, dimethylamine, diethylamine, di-n-propylamine, di-i-propylamine, di-n-butylamine, di-i-butylamine, di-t-butylamine, dipentylamines, dihexylamines, dioctylamines, didecylamines, dibenzylamines, methylethylamine, methylpropylamine, methylbutylamine, cyclohexylamine, N-phenylmethanolamine, N-phenylethanolamine, N-phenylpropanolamine, N-(m-methylphenyl)ethanolamine, N-(p-methylphenyl)ethanolamine, N-(2',6'-dimethylphenyl)ethanolamine, N-(p-chlorophenyl)ethanolamine, N-ethylaniline, N-butylaniline, N-methyl-2-methylaniline, N-methyl-2,6-dimethylaniline, and diphenylamine.

[0056] A tertiary monoamine compound may also be included as a constituent of the polymerization catalyst. Tertiary monoamine compounds are aliphatic tertiary amines, including alicyclic tertiary amines. Examples include trimethylamine, triethylamine, tripropylamine, tributylamine, triisobutylamine, dimethylethylamine, dimethylpropylamine, allyldiethylamine, dimethyl-n-butylamine, diethylisopropylamine, and N-methylcyclohexylamine. These tertiary monoamines may be used alone or in combination of two or more. The amount of these compounds used is not particularly limited, but is preferably 15 moles or less per 100 moles of the phenol compound added to the polymerization reaction.

[0057] In this embodiment, there is no limitation on adding a surfactant that has been known to have an effect of improving polymerization activity, such as trioctylmethylammonium chloride, which is known under the trade names Aliquat 336 and Capriquat.

[0058] As the oxygen-containing gas in the polymerization, in addition to pure oxygen, a mixture of oxygen and an inert gas such as nitrogen in any ratio, air, or a mixture of air and an inert gas such as nitrogen in any ratio can be used. Normal pressure is sufficient for the pressure in the system during the polymerization reaction, but either reduced or increased pressure can be used as necessary.

[0059] The polymerization temperature is not particularly limited, but if it is too low, the reaction will not proceed easily, and if it is too high, there is a risk of a decrease in reaction selectivity or the formation of a gel, so it is in the range of 0 to 60°C, preferably 10 to 40°C.

[0060] In the method for producing polyphenylene ether, the polymerization can also be carried out in a poor solvent such as alcohol.

[0061] Furthermore, in the production of polyphenylene ether, there are no particular limitations on the post-treatment method after the polymerization reaction is completed. Typically, an acid such as hydrochloric acid or acetic acid, or ethylenediaminetetraacetic acid (EDTA) and its salts, nitrilotriacetic acid and its salts, or the like is added to the reaction solution to deactivate the catalyst. Furthermore, the dihydric phenol by-products generated by the polymerization of polyphenylene ether can be removed using conventionally known methods. As described above, if the metal ions serving as the catalyst are substantially deactivated, the mixture can be decolorized simply by heating. Alternatively, a method in which a required amount of a known reducing agent is added is also possible. Examples of known reducing agents include hydroquinone and sodium dithionite.

[0062] In the method for producing polyphenylene ether, water may be added to extract the compound that has deactivated the copper catalyst, and then liquid-liquid separation into an organic phase and an aqueous phase may be performed, followed by removing the aqueous phase to remove the copper catalyst from the organic phase. This liquid-liquid separation step is not particularly limited, and examples thereof include static separation and separation using a centrifuge. In order to promote the liquid-liquid separation, a known surfactant or the like may be used.

[0063] Subsequently, in the method for producing polyphenylene ether of the present embodiment, the organic phase containing the polyphenylene ether after liquid-liquid separation may be concentrated and dried by volatilizing the solvent.

[0064] The method for volatilizing the solvent contained in the organic phase is not particularly limited, and examples thereof include a method of transferring the organic phase to a high-temperature concentration tank and concentrating the organic phase by distilling off the solvent, and a method of concentrating the organic phase by distilling off toluene using equipment such as a rotary evaporator.

[0065] The temperature for the drying treatment in the drying step is preferably at least 60° C. or higher, more preferably 80° C. or higher, even more preferably 120° C. or higher, and most preferably 140° C. or higher. When the polyphenylene ether is dried at a temperature of 60° C. or higher, the content of high-boiling-point volatile components in the polyphenylene ether powder can be efficiently reduced.

[0066] In order to obtain the polyphenylene ether with high efficiency, a method of increasing the drying temperature, a method of increasing the degree of vacuum in the drying atmosphere, a method of stirring during drying, and the like are effective, but a method of increasing the drying temperature is particularly preferred from the viewpoint of production efficiency. In the drying step, it is preferable to use a dryer equipped with a mixing function. Examples of the mixing function include a stirring type dryer and a tumbling type dryer. This allows the processing amount to be increased and productivity to be maintained at a high level.

[0067] The resin composition according to the present embodiment contains the polyphenylene ether, bis(vinylphenyl)ethane, and organic peroxide described above, and may further contain, if desired, a thermoplastic resin, a flame retardant, other additives, a solvent, etc. The components of the resin composition according to the present embodiment will be described below.

[0068] (bis(vinylphenyl)ethane) The resin composition of this embodiment contains bis(vinylphenyl)ethane as a crosslinking agent, which has the ability to initiate or accelerate a crosslinking reaction. Bis(vinylphenyl)ethane is a positional isomer depending on the bonding position of the vinyl group to the benzene ring, and one type may be used alone or multiple types may be used in combination. Examples of positional isomers include 1,2-bis(4-vinylphenyl)ethane, 1,2-bis(3-vinylphenyl)ethane, and 1-(3-vinylphenyl)-2-(4-vinylphenyl)ethane. The structure of the positional isomer is not particularly limited, but 1,2-bis(4-vinylphenyl)ethane is preferably used because of its easy availability. The mass ratio of polyphenylene ether to bis(vinylphenyl)ethane (polyphenylene ether:bis(vinylphenyl)ethane) is 30:70 to 70:30, and preferably 40:60 to 65:35, from the viewpoints of improving the compatibility between bis(vinylphenyl)ethane and polyphenylene ether, the coatability of the resin composition, and the properties of the mounted electronic circuit board.

[0069] (organic peroxide) In addition to polyphenylene ether and bis(vinylphenyl)ethane, the resin composition of this embodiment can use any organic peroxide capable of accelerating a polymerization reaction. Examples of the organic peroxides include benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, t-butylcumyl peroxide, di(2-t-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumyl peroxide, di-t-butylperoxyisophthalate, t-butylperoxybenzoate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide, and trimethylsilyltriphenylsilyl peroxide. Radical generators such as 2,3-dimethyl-2,3-diphenylbutane can also be used as a reaction initiator for the resin composition. Among them, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, di(2-t-butylperoxyisopropyl)benzene, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexane are preferred from the viewpoint of providing a cured product having excellent heat resistance and mechanical properties and a low dielectric dissipation factor (and preferably a low dielectric constant).

[0070] The one-minute half-life temperature of the organic peroxide is preferably 155 to 195°C, more preferably 160 to 195°C, and even more preferably 165 to 195°C. In this specification, the one-minute half-life temperature refers to the temperature at which the organic peroxide decomposes and the amount of active oxygen in the organic peroxide is reduced to half in one minute. The one-minute half-life temperature is determined by dissolving the organic peroxide in a solvent inert to radicals, such as benzene, to a concentration of 0.05 to 0.1 mol / L, and then thermally decomposing the organic peroxide solution in a nitrogen atmosphere.

[0071] When the organic peroxide has a one-minute half-life temperature of 155°C or higher, the polyphenylene ether is sufficiently melted before the reaction with the crosslinking agent begins when the polyphenylene ether-containing resin composition is subjected to heat and pressure molding, which tends to result in excellent moldability. On the other hand, when the organic peroxide has a one-minute half-life temperature of 195°C or lower, the decomposition rate of the organic peroxide is sufficient under normal heat and pressure molding conditions (e.g., a maximum temperature of 200°C), allowing the crosslinking reaction with the crosslinking agent to proceed efficiently and slowly, making it possible to form a cured product with good electrical properties (particularly dielectric tangent).

[0072] Examples of the organic peroxides having a one-minute half-life temperature in the range of 155 to 195°C include t-hexylperoxyisopropyl monocarbonate (155.0°C), t-butylperoxy-3,5,5-trimethylhexanoate (166.0°C), t-butylperoxylaurate (159.4°C), t-butylperoxyisopropyl monocarbonate (158.8°C), t-butylperoxy 2-ethylhexyl monocarbonate (161.4°C), t-hexylperoxybenzoate (160.3°C), 2,5-dimethyl-2,5-di(benzoylperoxy)hexane (158.2°C), t-butylperoxyacetate (15 9.9°C), 2,2-di-(t-butylperoxy)butane (159.9°C), t-butyl peroxybenzoate (166.8°C), n-butyl 4,4-di-(t-butylperoxy)valerate (172.5°C), di(2-t-butylperoxyisopropyl)benzene (175.4°C), dicumyl peroxide (175.2°C), di-t-hexyl peroxide (176.7°C), 2,5-dimethyl-2,5-di(t-butylperoxy)hexane (179.8°C), 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3 (194.3°C), and t-butylcumyl peroxide (173.3°C).

[0073] The content of the organic peroxide is preferably 0.05 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 1.0 part by mass or more, and particularly preferably 1.5 parts by mass or more, relative to 100 parts by mass of the total of (A) polyphenylene ether and (B) bis(vinylphenyl)ethane, from the viewpoint of being able to increase the reaction rate. Furthermore, the content of the organic peroxide is preferably 10 parts by mass or less, more preferably 5.0 parts by mass or less, and even more preferably 4.5 parts by mass or less, relative to 100 parts by mass of the total of (A) polyphenylene ether and (B) bis(vinylphenyl)ethane, from the viewpoint of being able to keep the dielectric constant and dielectric dissipation factor of the obtained cured product low.

[0074] The content of the organic peroxide is preferably 0.1 to 50 parts by mass, more preferably 1.0 to 25 parts by mass, even more preferably 2.0 to 22.5 parts by mass, still more preferably 2.5 to 21.5 parts by mass, and particularly preferably more than 3.0 to 20 parts by mass, per 100 parts by mass of bis(vinylphenyl)ethane. A content of 0.1 parts by mass or more tends to increase the reaction rate, and a content of 50 parts by mass or less tends to reduce the dielectric constant and dielectric loss tangent of the resulting cured product.

[0075] (thermoplastic resin) The resin composition of the present embodiment may further contain a thermoplastic resin. The thermoplastic resin is preferably at least one selected from the group consisting of a block copolymer of a vinyl aromatic compound and an olefinic alkene compound, a hydrogenated product thereof (a hydrogenated block copolymer obtained by hydrogenating a block copolymer of a vinyl aromatic compound and an olefinic alkene compound), and a homopolymer of a vinyl aromatic compound. The content of units derived from a vinyl aromatic compound in the block copolymer or its hydrogenated product is preferably 20% by mass or more, more preferably 22% by mass or more, and can be 99% by mass or less. When the content of units derived from a vinyl aromatic compound in the block copolymer or its hydrogenated product is 20% by mass or more, compatibility with polyphenylene ether is further improved, and adhesion strength to metal foil tends to be further improved.

[0076] The vinyl aromatic compound may be any compound having an aromatic ring and a vinyl group in the molecule, such as styrene, etc. The olefinic alkene compound may be any compound having a linear or branched structure in the molecule, such as ethylene, propylene, butylene, isobutylene, butadiene, and isoprene, etc. Among these, from the viewpoint of even better compatibility with polyphenylene ether, the thermoplastic resin is preferably at least one selected from the group consisting of styrene-butadiene block copolymer, styrene-ethylene-butadiene block copolymer, styrene-ethylene-butylene block copolymer, styrene-butadiene-butylene block copolymer, styrene-isoprene block copolymer, styrene-ethylene-propylene block copolymer, styrene-isobutylene block copolymer, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-ethylene-butadiene block copolymer, hydrogenated styrene-butadiene-butylene block copolymer, hydrogenated styrene-isoprene block copolymer, and styrene homopolymer (polystyrene), and more preferably at least one selected from the group consisting of styrene-butadiene block copolymer, hydrogenated styrene-butadiene block copolymer, and polystyrene.

[0077] The hydrogenation rate of the hydrogenated product is not particularly limited, and some carbon-carbon unsaturated double bonds derived from the olefinic alkene compound may remain.

[0078] The weight-average molecular weight of the thermoplastic resin is preferably 10,000 to 300,000, more preferably 20,000 to 290,000, and even more preferably 30,000 to 280,000. When the weight-average molecular weight is 10,000 or more, the resin composition of this embodiment tends to have better heat resistance when cured. When the weight-average molecular weight is 300,000 or less, the resin composition of this embodiment tends to have better resin fluidity during heat molding. The weight average molecular weight can be measured using a gel permeation chromatograph as a measuring device, a calibration curve prepared using standard polystyrene, and the calibration curve used.

[0079] The content of the thermoplastic resin is preferably 2 to 20 parts by mass, more preferably 3 to 19 parts by mass, even more preferably 4 to 18 parts by mass, and particularly preferably 5 to 17 parts by mass, based on 100 parts by mass of the total of polyphenylene ether and bis(vinylphenyl)ethane. When the content is 2 parts by mass or more, the resin composition of this embodiment tends to have even better low dielectric constant, low dielectric loss tangent, and adhesion to metal foil when cured. When the content is 20 parts by mass or less, the resin composition of this embodiment tends to have even better resin fluidity during heat molding.

[0080] The resin composition of the present embodiment may also contain a thermoplastic resin other than the thermoplastic resin of the type and having the weight average molecular weight described above.

[0081] (Flame retardant) The resin composition of the present embodiment preferably further contains a flame retardant. The flame retardant is not particularly limited as long as it is compatible with other components contained in the resin composition after curing, from the viewpoint of improving heat resistance. Examples of flame retardants include inorganic flame retardants such as antimony trioxide, aluminum hydroxide, magnesium hydroxide, and zinc borate; aromatic bromine compounds such as hexabromobenzene, decabromodiphenylethane, 4,4-dibromobiphenyl, and ethylene bistetrabromophthalimide; and phosphorus-based flame retardants such as resorcinol bis-diphenyl phosphate and resorcinol bis-dixylenyl phosphate. These flame retardants may be used alone or in combination of two or more. Among these, decabromodiphenylethane is preferred as the flame retardant from the viewpoints of compatibility between the flame retardant and polyphenylene ether, coatability of the resin composition, and superior properties of the electronic circuit boards mounted thereon.

[0082] The content of the flame retardant is not particularly limited, but from the viewpoint of maintaining flame retardancy at V-0 level of UL Standard 94, it is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more per 100 parts by mass of the total of polyphenylene ether and bis(vinylphenyl)ethane. Furthermore, from the viewpoint of maintaining a low dielectric loss tangent of the obtained cured product (and preferably also a low dielectric constant), the content of the flame retardant is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, and even more preferably 40 parts by mass or less.

[0083] (Silica filler) The resin composition of this embodiment may further contain a silica filler. Examples of silica fillers include natural silica, fused silica, synthetic silica, amorphous silica, aerosil, and hollow silica. The content of the silica filler may be 10 to 300 parts by mass per 100 parts by mass of the total of polyphenylene ether and bis(vinylphenyl)ethane. The silica filler may be surface-treated with a silane coupling agent or the like.

[0084] In addition to the flame retardant and the silica filler, the resin composition of the present embodiment may further contain additives such as a heat stabilizer, an antioxidant, a UV absorber, a surfactant, a lubricant, a solvent, etc. When the resin composition of the present embodiment contains a solvent, it can be in the form of a varnish in which the solid components in the resin composition are dissolved or dispersed in the solvent, and a resin film can be formed from the resin composition of the present embodiment.

[0085] (solvent) The resin composition of this embodiment may further contain a solvent. From the viewpoint of solubility, preferred solvents include aromatic compounds such as toluene and xylene, methyl ethyl ketone (MEK), cyclopentanone, cyclohexanone, and chloroform. These solvents may be used alone or in combination of two or more.

[0086] <Resin film> The resin film of the present embodiment contains the resin composition of the present embodiment. The method for producing the film is not particularly limited, and the film can be obtained, for example, by molding the resin composition of the present embodiment into a film or sheet.

[0087] <Prepreg> The prepreg of this embodiment is a composite of a substrate and the resin composition of this embodiment, and the substrate may be impregnated with or coated with the resin composition of this embodiment. The method for producing the prepreg is not particularly limited, but for example, the prepreg can be obtained by impregnating the substrate with a resin composition (varnish) containing a solvent, and then drying and removing the solvent using a hot air dryer or the like.

[0088] Examples of the substrate include various glass cloths such as roving cloth, cloth, chopped mat, and surfacing mat; asbestos cloth, metal fiber cloth, and other synthetic or natural inorganic fiber cloths; woven or nonwoven fabrics obtained from liquid crystal fibers such as wholly aromatic polyamide fibers, wholly aromatic polyester fibers, and polybenzoxazole fibers; natural fiber cloths such as cotton cloth, linen cloth, and felt; natural cellulose-based substrates such as carbon fiber cloth, kraft paper, cotton paper, and fabrics obtained from paper-glass blended yarns; and polytetrafluoroethylene porous films. Among these, glass cloth is preferred. These substrates may be used alone or in combination of two or more.

[0089] The proportion of the resin composition solids (components of the resin composition other than the solvent) in the prepreg of this embodiment is preferably 30 to 80 mass %, more preferably 40 to 70 mass %. Having this proportion of 30 mass % or more tends to provide better insulation reliability when the prepreg is used for electronic substrates, etc. Having this proportion of 80 mass % or less tends to provide better mechanical properties, such as flexural modulus, when used in electronic substrates, etc.

[0090] <Metal-clad laminate> The metal-clad laminate of this embodiment can be obtained by laminating and curing the resin composition of this embodiment, the resin film of this embodiment, or the prepreg of this embodiment described above with a metal foil. The metal-clad laminate of this embodiment preferably has a configuration in which a cured product of the prepreg (hereinafter also referred to as a "cured composite") and a metal foil are laminated and adhered together, and is suitable for use as a material for electronic substrates. Examples of metal foil include aluminum foil and copper foil, and among these, copper foil is preferred because of its low electrical resistance. The cured composite to be combined with the metal foil may be one sheet or multiple sheets, and depending on the application, metal foil is layered on one or both sides of the composite to form a laminate.

[0091] A method for producing the metal-clad laminate of this embodiment includes, for example, forming a composite (e.g., the above-mentioned prepreg) composed of a resin composition and a substrate, overlaying this on a metal foil, and then curing the resin composition to obtain a laminate in which the cured laminate and the metal foil are laminated. One particularly preferred application of the metal-clad laminate is a printed wiring board. The printed wiring board is preferably a metal-clad laminate from which at least a portion of the metal foil has been removed.

[0092] <Printed wiring board> The printed wiring board of this embodiment has a portion of the metal foil removed from the metal-clad laminate of this embodiment. The printed wiring board of this embodiment can typically be formed by a method of pressurizing and hot molding using the prepreg of the present invention described above. Examples of the substrate include those similar to those described above for the prepreg. The printed wiring board of this embodiment has excellent dielectric loss tangent and copper foil peel strength by containing the resin composition of this embodiment. [Example]

[0093] Hereinafter, the present embodiment will be described in more detail based on examples, but the present embodiment is not limited to the following examples.

[0094] <Polyphenylene ether> (Production Example 1) Polyphenylene ether 1 (PPE1) A 40-liter jacketed polymerization vessel equipped with a sparger, stirring turbine blades, and baffles at the bottom of the vessel for introducing an oxygen-containing gas and a reflux condenser on a vent gas line at the top of the vessel was charged with 3.6 g of cupric oxide, 27.1 g of a 47% by mass aqueous hydrogen bromide solution, 8.7 g of di-tert-butylethylenediamine, 42.0 g of di-n-butylamine, 128.0 g of butyldimethylamine, 14.6 kg of toluene, and 2.0 g of trioctylmethylammonium chloride (R=C8-C10) while blowing nitrogen gas into the vessel at a flow rate of 46.3 L / min, to prepare a homogeneous solution. Next, a pump was used to dropwise add a solution of 575.3 g of 2-tert-butyl-5-methylphenol, 2424.7 g of 2,6-dimethylphenol, and 2.35 kg of toluene to the polymerization vessel over 35 minutes. At the same time, dry air was introduced into the polymerization solution from the bottom of the vessel via a sparger at a rate of 31.5 L / min to initiate polymerization. Dry air was sparged for 240 minutes to obtain a polymerization mixture. The internal temperature was controlled to 40°C during polymerization. The polymerization mixture (polymerization liquid) was in a homogeneous solution state at the end of polymerization. The dry air flow was then stopped, and 38.73 g of ethylenediaminetetraacetic acid tetrasodium salt (a reagent manufactured by Dojindo Laboratories) was added to the polymerization mixture as a 2 kg aqueous solution. The polymerization mixture was stirred at 70°C for 240 minutes, then allowed to stand for 20 minutes, and the organic and aqueous phases were separated by liquid-liquid separation. The organic phase was concentrated using a rotary evaporator until the polymer concentration reached 30% by mass. The concentrated solution was mixed with methanol such that the mass ratio of methanol to polymer solution was 4, and the polymer was precipitated. Wet polyphenylene ether was obtained by filtration under reduced pressure using a glass filter. The wet polyphenylene ether was further washed with an amount of methanol such that the mass ratio of methanol to wet polyphenylene ether was 4, and this washing operation was repeated three times. Thereafter, the wet polyphenylene ether was kept at 140°C and 1 mmHg for 120 minutes, and a dry polyphenylene ether (PPE1) was obtained.

[0095] (Production Example 2) Polyphenylene ether 2 (PPE2) A polyphenylene ether was obtained in the same manner as in Production Example 1, except that 647.8 g of 2-tert-butyl-5-methylphenol and 2352.3 g of 2,6-dimethylphenol were used.

[0096] (Production Example 3) Polyphenylene ether 3 (PPE3) A 500 mL three-neck flask equipped with a temperature controller, stirrer, cooling equipment, and dropping funnel was charged with 50 g of PPE2, 2 g of p-chloromethylstyrene, 0.1 g of tetra-n-butylammonium bromide, and 150 g of toluene. The mixture was then stirred and dissolved, and the liquid temperature was raised to 85°C. A sodium hydroxide aqueous solution (1.5 g of sodium hydroxide / 1.6 g of water) was added dropwise to the mixture, and stirring was continued at 85°C for an additional 5 hours. Next, the resulting aqueous layer was removed using a separatory funnel to obtain a toluene layer containing the polymer (polymer solution). The polymer solution was mixed with methanol at a methanol to methanol ratio of 10 to 10, allowing precipitation of the polymer. Wet polyphenylene ether was obtained by filtration under reduced pressure using a glass filter. The wet polyphenylene ether was then washed with methanol. After washing, the wet polyphenylene ether was maintained at 140°C and 1 mmHg for 120 minutes to obtain dry polyphenylene ether (PPE3).

[0097] (Production Example 4) Polyphenylene ether 4 (PPE4) A polyphenylene ether was obtained in the same manner as in Production Example 1, except that 1096.7 g of 2-tert-butyl-5-methylphenol and 1903.3 g of 2,6-dimethylphenol were used. 50 g of the obtained polyphenylene ether, 11.5 g of p-chloromethylstyrene, 0.5 g of tetra-n-butylammonium bromide, and 150 g of toluene were added to a 500 mL three-neck flask equipped with a temperature controller, a stirrer, a cooling device, and a dropping funnel. The mixture was then stirred and dissolved, and the liquid temperature was raised to 85°C. A sodium hydroxide aqueous solution (8.0 g of sodium hydroxide / 8.7 g of water) was added dropwise to the mixture, and stirring was continued at 85°C for an additional 5 hours. Next, the resulting aqueous layer was removed using a separatory funnel, and a toluene layer containing the polymer (polymer solution) was obtained. The polymer solution was mixed with methanol at a methanol to methanol ratio of 10, and the polymer was precipitated. Wet polyphenylene ether was obtained by filtration under reduced pressure using a glass filter. The wet polyphenylene ether was then washed with methanol. After washing, the wet polyphenylene ether was kept at 140°C and 1 mmHg for 120 minutes to obtain dry polyphenylene ether (PPE4).

[0098] (Production Example 5) Polyphenylene ether 5 (PPE5) A polyphenylene ether (PPE5) was obtained in the same manner as in Production Example 4, except that 1720.4 g of 2-tert-butyl-5-methylphenol and 1279.6 g of 2,6-dimethylphenol were used instead.

[0099] (Production Example 6) Polyphenylene ether 6 (PPE6) Polyphenylene ether (PPE6) was obtained by carrying out the same operation as in Production Example 4, except that 510.8 g of 2-tert-butyl-5-methylphenol, 1899.6 g of 2,6-dimethylphenol, and 589.6 g of tetramethylbisphenol A were used as phenol monomers.

[0100] Polyphenylene ether 7 (PPE7) "NORYL SA9000" manufactured by SABIC was used as PPE7.

[0101] Polyphenylene ether 8 (PPE8) "XYRON S203A" manufactured by Asahi Kasei Corporation was used as PPE8.

[0102] (Analysis of polyphenylene ether) The following analyses were carried out on PPE1 to 8. The analysis results are shown in Table 1.

[0103] (1) Reduced viscosity of polyphenylene ether (ηsp / c) A 0.5 g / dL chloroform solution of polyphenylene ether was prepared, and the reduced viscosity (ηsp / c) (dL / g) at 30°C was determined using an Ubbelohde viscosity tube.

[0104] [Table 1]

[0105] <Components other than polyphenylene ether> (bis(vinylphenyl)ethane) TIFF2025161762000019.tif8165

[0106] (organic peroxide) Bis(1-tert-butylperoxy-1-methylethyl)benzene (product name: Perbutyl P, manufactured by NOF Corporation, 1-minute half-life temperature: 175.4°C)

[0107] (thermoplastic resin) Hydrogenated styrene-based thermoplastic resin (SEBS) (product name: Tuftec H1041, manufactured by Asahi Kasei Corporation, weight-average molecular weight: approximately 90,000, styrene unit content: 32% by mass)

[0108] (Flame retardant) Decabromodiphenylethane (product name: SAYTEX8010, manufactured by Albemarle)

[0109] (filler) Spherical silica (product name: SO-C6, manufactured by Admatechs Co., Ltd.)

[0110] (copper foil) HVLP3 copper foil (product name: F1N-WS, manufactured by Furukawa Electric Co., Ltd., Rz=0.8μm) ·HVLP copper foil (product name: FV-WS, manufactured by Furukawa Electric Co., Ltd., Rz=1.2μm)

[0111] As shown below, cured products were prepared from the resin compositions of the respective Examples and Comparative Examples.

[0112] Example 1 According to the composition and solvent shown in Table 2, a thermoplastic resin was added to 134 parts by mass of toluene, stirred and dissolved, and then bis(vinylphenyl)ethane, a flame retardant, spherical silica, and PPE1 synthesized by the above method were added, and stirring was continued until PPE1 was dissolved. Next, an organic peroxide was added to the solution, and the mixture was thoroughly stirred to obtain a varnish. The obtained varnish was impregnated into an L-shaped glass cloth, which was then passed through a slit of a specified width to scrape off excess varnish. The cloth was then dried in a drying oven at 130°C for a specified time to remove the toluene, thereby obtaining a prepreg. The obtained prepreg was cut to a predetermined size, and a predetermined number of sheets were stacked. The stacked prepreg sheets were then laminated with the above-mentioned copper foils on both sides, and vacuum pressed to obtain a copper-clad laminate. In the vacuum pressing process, first, a pressure of 40 kg / cm was applied. 2 The temperature was raised from 30°C to 200°C at a rate of 2°C / min while applying pressure of 40 kg / cm. 2 The temperature was maintained at 200°C for 60 minutes with the pressure applied. The copper foil was removed from the copper-clad laminate by etching, to obtain a sample laminate.

[0113] (Examples 2 to 9, Comparative Examples 1 to 8) A varnish, a prepreg, and a copper-clad laminate were obtained under the same conditions as in Example 1, except that the resin composition was changed as shown in Table 2. In Comparative Example 8, in which PPE8 was used, the PPE was not completely dissolved in toluene, and it was not possible to prepare a prepreg or a copper-clad laminate.

[0114] <Evaluation> The samples obtained in the above Examples and Comparative Examples were evaluated as follows.

[0115] (1) Dielectric tangent The dielectric loss tangents at 10 GHz of the cured resin compositions prepared in the examples and comparative examples were measured by the split cylinder method using a network analyzer (N5227B, manufactured by Keysight Technologies) and a split cylinder resonator (CR-710, manufactured by EM Lab Co., Ltd.).

[0116] The cured resin composition, approximately 0.5 mm thick, prepared by the method described above was cut into a plate 50 mm long and 50 mm wide. It was then placed in an oven at 105°C ± 3°C to dry for 1 hour, and then left to stand for 24 ± 2 hours in an environment at 23°C and a relative humidity of 50 ± 2%. The dielectric loss tangent was then measured using the measuring device described above in an environment at 23°C and a relative humidity of 50 ± 2%.

[0117] (2) Copper foil peel strength The stress when peeling the copper foil from the copper-clad laminate at a constant speed was measured. The copper-clad laminates obtained in the above-mentioned Examples and Comparative Examples were cut into a size of 10 mm wide x 120 mm long, and the copper foil was peeled at an angle of 90 degrees to the removal surface at a speed of 50 mm / min using an autograph (Shimadzu Corporation, AG-I20kN). The average load was measured and calculated as the average of three measurements.

[0118] [Table 2]

[0119] As shown in Table 2, the resin compositions using PPE1 to 4 and 6 exhibited superior dielectric loss tangents and peel strength from copper foil with low roughness compared to the respective comparative examples. [Industrial Applicability]

[0120] The resin composition containing the polyphenylene ether of the present invention has excellent dielectric loss tangent and peel strength from low-roughness copper foil, and therefore has industrial applicability as an electronic material and a modifier.

Claims

1. A resin composition comprising (A) polyphenylene ether, (B) bis(vinylphenyl)ethane, and (C) an organic peroxide, The polyphenylene ether (A) contains a repeating unit derived from a phenol represented by the following formula (1) and a repeating unit derived from a phenol represented by the following formula (2), 【Chemical 1】 (In formula (1), R １１ are each independently an optionally substituted saturated hydrocarbon group having 1 to 6 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, or a halogen atom; R １２ are each independently a hydrogen atom, an optionally substituted hydrocarbon group having 1 to 6 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, or a halogen atom. 【Chemistry 2】 (In formula (2), R ２２ are each independently a hydrogen atom, an optionally substituted saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, or a halogen atom; ２２ are not both hydrogen atoms, and R ２１ is a partial structure represented by the following formula (3): 【Chemistry 3】 (In formula (3), R ３１ are each independently an optionally substituted linear alkyl group having 1 to 8 carbon atoms, or two R ３１ is a cyclic alkyl structure having 1 to 8 carbon atoms to which R ３２ are each independently an optionally substituted alkylene group having 1 to 8 carbon atoms, each b is independently 0 or 1, and R ３３ is a hydrogen atom, an optionally substituted alkyl group having 1 to 8 carbon atoms, or an optionally substituted phenyl group. The polyphenylene ether (A) contains 55 mol % or more and 95 mol % or less of repeating units derived from a phenol of the formula (1) and 5 mol % or more and 45 mol % or less of repeating units derived from a phenol of the formula (2), relative to a total of 100 mol % of repeating units derived from a phenol of the formula (1) and repeating units derived from a phenol of the formula (2), A resin composition characterized in that the mass ratio of the (A) polyphenylene ether to the (B) bis(vinylphenyl)ethane is 30:70 to 70:

30.

2. 2. The resin composition according to claim 1, wherein the partial structure represented by the formula (3) is a t-butyl group.

3. The resin composition according to claim 1, characterized in that the polyphenylene ether has a reduced viscosity (ηsp / c) of 0.03 to 0.30 dL / g as measured in a chloroform solution having a concentration of 0.5 g / dL at 30 °C.

4. 2. The resin composition according to claim 1, wherein the bis(vinylphenyl)ethane (B) is 1,2-bis(4-vinylphenyl)ethane.

5. A prepreg, which is a composite of a substrate and the resin composition according to any one of claims 1 to 4.

6. The prepreg according to claim 5, wherein the substrate is a glass cloth.

7. A metal-clad laminate, which is a laminate of a cured product of the prepreg according to claim 5 and a metal foil.

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