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

Abstract

To provide a resin composition that contains polyphenylene ether with excellent solvent solubility, and also exhibits superior copper foil peel strength and toluene resistance.SOLUTION: The resin composition comprises: (A) polyphenylene ether; (B) triallyl isocyanurate and / or triallyl cyanurate; and (C) an organic peroxide. The polyphenylene ether (A) includes predetermined amounts of repeating units derived from phenol of formula (1) in the figure and repeating units derived from phenol of formula (2) in the figure. The polyphenylene ether (A) has a molecular weight distribution (Mw / Mn) of 2.0 to 6.0, and has 0.8 to 2.5 OH groups per molecule.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] Polyphenylene ether (hereinafter, also referred to as "PPE") has excellent high-frequency characteristics, flame retardancy, and heat resistance, and is therefore widely used as a material for products and parts in the electrical and electronics, automotive, and food and packaging fields, as well as in various other industrial materials. In particular, in recent years, its low dielectric properties and heat resistance have led to its application as a modifier in various applications, including electrical and electronic applications such as circuit board materials.

[0003] However, in general, high molecular weight polyphenylene ethers having repeating units derived from monohydric phenols such as 2,6-dimethylphenol have the problem that, although they dissolve in highly toxic solvents such as chloroform, they are poorly soluble at high concentrations at room temperature in aromatic solvents such as toluene, which are known to be good solvents, and are insoluble in ketone solvents such as methyl ethyl ketone. Therefore, when used as a wiring board material, for example, it is difficult to handle them in resin varnish solutions such as toluene and methyl ethyl ketone.

[0004] Patent Document 1 discloses a resin composition in which a varnish is prepared by heating and melting polyphenylene ether in an aromatic solvent in order to improve the solubility and dispersibility of polyphenylene ether. Furthermore, Patent Document 2 discloses polyphenylene ether having excellent solubility in general-purpose ketone solvents, and a thermosetting composition using the polyphenylene ether. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3151397 [Patent Document 2] International Publication No. 2022 / 158180 Summary of the Invention [Problem to be solved by the invention]

[0006] However, even when a resin composition such as that described in Patent Document 1 was used, a resin composition containing polyphenylene ether that dissolves in toluene at room temperature (has solvent solubility) could not be obtained, and there were further issues with the copper foil peel strength and toluene resistance of the cured resin composition. Furthermore, even when the resin composition described in Patent Document 2 is used, a polyphenylene ether having excellent solubility in organic solvents such as toluene and methyl ethyl ketone can be obtained, but there is no disclosure regarding the copper foil peel strength and toluene resistance of the cured resin composition.

[0007] The present invention has been made in consideration of the above problems, and has an object to provide a resin composition which contains polyphenylene ether having excellent solvent solubility, and which also has excellent copper foil peel strength and toluene resistance. Another object 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]

[0008] That is, the present invention is as follows. (1)(A) polyphenylene ether, (B) triallyl isocyanurate and / or triallyl cyanurate, (B') a crosslinking agent other than triallyl isocyanurate and triallyl cyanurate as an optional component, (C) a resin composition containing 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), With respect to 100 mol % in total of the repeating units of the following formula (1) and the following formula (2), the content of the repeating unit derived from phenol of the following formula (1) is 70 mol % or more and less than 85 mol %, and the content of the repeating unit derived from phenol of the following formula (2) is more than 15 mol % and 30 mol % or less, The molecular weight distribution (Mw / Mn) determined by gel permeation chromatography (GPC) is 2.0 to 6.0; A resin composition having 0.8 to 2.5 OH groups per molecule. [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 is not both hydrogen atoms, R 21 is a partial structure represented by the following formula (3). [ka] (In formula (3), R 31 each independently represents 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, R 32 each independently represents an optionally substituted alkylene group having 1 to 8 carbon atoms; each b independently represents 0 or 1; R 33is a hydrogen atom, an optionally substituted alkyl group having 1 to 8 carbon atoms, or an optionally substituted phenyl group. (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 (A) polyphenylene ether has a reduced viscosity (ηsp / c) of 0.13 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 (A) polyphenylene ether has a number of OH groups per 1 g of the polyphenylene ether of 100 to 300 μmol / g. (5) The resin composition according to any one of (1) to (4), characterized in that a mass ratio (A:B) of the (A) polyphenylene ether to the (B) triallyl isocyanurate and / or triallyl cyanurate is 50:50 to 80:20. (6) The resin composition according to any one of (1) to (5), characterized in that it contains 0.05 parts by mass or more and 10 parts by mass or less of the (C) organic peroxide relative to a total of 100 parts by mass of the (A) polyphenylene ether, the (B) triallyl isocyanurate and / or triallyl cyanurate, and the (B') crosslinking agent other than triallyl isocyanurate and triallyl cyanurate. (7) The resin composition according to (6), characterized in that it contains 1.0 part by mass or more and 5.0 parts by mass or less of the (C) organic peroxide per 100 parts by mass in total of the (A) polyphenylene ether, the (B) triallyl isocyanurate and / or triallyl cyanurate, and the (B') crosslinking agent other than triallyl isocyanurate and triallyl cyanurate. (8) The resin composition according to any one of (1) to (7), characterized in that it contains 0.1 parts by mass or more and 50 parts by mass or less of the (C) organic peroxide relative to a total of 100 parts by mass of the (B) triallyl isocyanurate and / or triallyl cyanurate, and the (B') crosslinking agent other than triallyl isocyanurate and triallyl cyanurate. (9) The resin composition according to any one of (1) to (8), wherein the (C) organic peroxide has a one-minute half-life temperature of 155°C to 195°C. (10) The resin composition according to any one of (1) to (9), further comprising a silica filler as a filler. (11) The resin composition according to any one of (1) to (10), further comprising a flame retardant, the flame retardant being incompatible with other components contained in the resin composition after the resin composition is cured. (12) A resin film comprising the resin composition according to any one of (1) to (11). (13) A prepreg, which is a composite of a substrate and the resin composition according to any one of (1) to (11). (14) The prepreg according to (13), characterized in that the base material is a glass cloth. (15) A metal-clad laminate, characterized in that it is a laminate of a cured product of the resin film according to (12) and a metal foil. (16) A metal-clad laminate, characterized in that it is a laminate of a cured product of the prepreg according to (13) and a metal foil. Effect of the Invention

[0009] According to the present invention, it is possible to provide a polyphenylene ether resin composition having excellent copper foil peel strength and toluene resistance. 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 PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment for carrying out the present invention (hereinafter, referred to as "the present embodiment") will be described in detail. The following embodiment is an example for explaining the present invention, and the present invention is not limited to only this embodiment, and the present invention can be carried out by appropriately modifying it within the scope of the gist of the present invention.

[0011] 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 there is a particular contradiction.

[0012] In this specification, A (numeric value) to B (numeric value) mean greater than or equal to A and less than or equal to B. 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.

[0013] <Resin composition> The resin composition of the present embodiment comprises: (A) polyphenylene ether; The resin composition contains (B) triallyl isocyanurate and / or triallyl cyanurate, (B') a crosslinking agent other than triallyl isocyanurate and triallyl cyanurate as an optional component, and (C) an organic peroxide.

[0014] (Polyphenylene ether) The polyphenylene ether contains at least 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), and may consist only of the repeating unit derived from a phenol represented by the following formula (1) and the 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 is not both hydrogen atoms, R 21 is a partial structure represented by the following formula (3). [ka] (In formula (3), R 31 each independently represents 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, 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.

[0015] 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 further preferably a methyl group. 11 Preferably, both have the same structure.

[0016] 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. 12 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).

[0017] In the above formula (2), R 22are 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).

[0018] 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 terminal thereof, more preferably a tert-butyl group or a cyclohexyl group, and even more preferably a tert-butyl group.

[0019] In this embodiment, the polyphenylene ether can be analyzed by NMR, mass spectrometry, or the like to identify its structure. A specific method for identifying the structure of the polyphenylene ether is to carry out field desorption mass spectrometry (FD-MS), which is known to be less prone to fragmentation, and to estimate the repeating units based on the intervals between the detected ions. In addition, a method for estimating the structure of the polyphenylene ether can be used in combination with peak analysis of fragment ions by electron ionization (EI) or structural analysis by NMR.

[0020] In this embodiment, the polyphenylene ether contains a repeating unit derived from phenol of the above formula (1) and a repeating unit derived from phenol of the above formula (2), and the content of the repeating unit derived from phenol of the above formula (1) is 70 mol% or more and less than 85 mol%, and the content of the repeating unit derived from phenol of the above formula (2) is more than 15 mol% and 30 mol% or less, relative to 100 mol% in total of the repeating units of the above formulas (1) and (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-mentioned ratio, and in addition to having excellent solvent solubility, the polyphenylene ether also has improved copper foil peel strength and toluene resistance of the substrate.

[0021] From a similar viewpoint, the polyphenylene ether preferably has a content of repeating units derived from phenol of the above formula (1) of 72 mol% or more and 84 mol% or less, and a content of repeating units derived from phenol of the above formula (2) of 16 mol% or more and 28 mol% or less, more preferably has a content of repeating units derived from phenol of the above formula (1) of 74 mol% or more and 83.5 mol% or less, and a content of repeating units derived from phenol of the above formula (2) of 16.5 mol% or more and 26 mol% or less, and further preferably has a content of repeating units derived from phenol of the above formula (1) of 75 mol% or more and 83 mol% or less, and a content of repeating units derived from phenol of the above formula (2) of 17 mol% or more and 25 mol% or less.

[0022] Since the phenol of the above formula (1) does not have an unsubstituted ortho position (i.e., since no hydrogen atoms are bonded to the carbon atoms at the two ortho positions of the carbon atom to which the hydroxyl group is bonded), it can react with another phenolic monomer only at the carbon atom at 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).

[0023] 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 repeat 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).

[0024] The polyphenylene ether may also contain a structural unit derived from phenol, as shown in 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 positions, 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.

[0025] In the above formula (7), R 4 are each independently any one of a linear alkyl group having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, and an n-propyl group, and 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 a solvent and a higher glass transition temperature after curing, it is preferable that the a partial structures are the same.

[0026] In the above formula (7), k is an integer of 1 to 4, and preferably an integer of 2 to 4.

[0027] In addition, in the above formula (7), R 4 is bonded to at least one of the carbon atoms at the 2-position and the 6-position, with the carbon atom of the benzene ring to which -O- is bonded being the 1-position, and R 3 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, and R bonded to the 2-position and / or the 6-position 4 When is a partial structure represented by formula (3), it is preferably bonded to only either the 2-position or the 6-position.

[0028] The polyphenylene ether may also contain repeat units derived from formula (7) above, as well as repeat units derived from a phenol of formula (1) above and / or repeat units derived from a phenol of formula (2) above. 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 both the phenol compound represented by formula (2) and the phenol compound represented by formula (7) are substituted with the partial structures (functional groups) represented by formula (3)), the structures of the partial structures (functional groups) represented by formula (3) may be the same or different.

[0029] Furthermore, in the above formula (7), X is any linking group having a valence of a, 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.

[0030] The above X is R 4 R is bonded to a benzene ring via an a-valent alkyl skeleton, a single bond, an ester bond, etc. 4 R is bonded to a benzene ring via an a-valent aryl skeleton, a single bond, an ester bond, or the like. 4 and an a-valent heterocyclic skeleton bonded to a benzene ring to which is bonded.

[0031] 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 units are directly bonded to a benzene ring in a partial structure (as long as a benzene ring is bonded to the a units of branched ends, there may be a branched end to which no benzene ring is bonded). In addition, 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 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 4 and the like.

[0032] In the above formula (7), a is an integer of 2 to 6, and preferably an integer of 2 to 4.

[0033] 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).

[0034] The polyphenylene ether has a reduced viscosity (ηsp / c) measured in a chloroform solution having a concentration of 0.5 g / dL at 30° C. of 0.13 to 0.30 dL / g, preferably 0.15 to 0.28 dL / g, and more preferably 0.17 to 0.25 dL / g. A reduced viscosity (ηsp / c) of 0.13 dL / g or more measured in a chloroform solution with a concentration of 0.5 g / dL at 30°C ensures high heat resistance and excellent dielectric properties derived from the polyphenylene ether structure, and a reduced viscosity (ηsp / c) of 0.30 dL / g or less ensures solubility in solvents such as toluene and methyl ethyl ketone. The reduced viscosity can be measured by the method described in the Examples below.

[0035] The polyphenylene ether has a molecular weight distribution (Mw / Mn) determined by gel permeation chromatography (GPC) of 2.0 to 6.0, preferably 2.5 to 5.5, and more preferably 3.0 to 5.0. By having a molecular weight distribution (Mw / Mn) of 2.0 or more as determined by gel permeation chromatography (GPC), the fluidity of the polyphenylene ether is improved, and its reactivity during heat curing is enhanced. By having a molecular weight distribution (Mw / Mn) of 6.0 or less, the toughness of the polyphenylene ether is improved, and the cured product has excellent copper foil peel strength and solvent resistance.

[0036] The means for adjusting the molecular weight distribution of the polyphenylene ether to the above range include adjusting the polymerization temperature, adjusting the catalyst equivalent, adjusting the monomer concentration in the reaction system, etc., from the viewpoint of controlling the polymerization reactivity. Among them, the method of adjusting the monomer concentration in the reaction system is preferably a method of gradually adding a monomer to the reaction system. When the monomer concentration in the reaction system is high from the beginning, the reaction rate between the monomers is high, so it is difficult to control the molecular weight of the polymer produced. On the other hand, by adding the monomer to the reaction system at an appropriate flow rate, the monomer concentration in the reaction system can be controlled, and the reaction rate can be easily controlled. As a result, a polymer having a molecular weight distribution in a preferred range can be obtained.

[0037] In this embodiment, the polyphenylene ether has a number of OH groups of 100 to 330 μmol / g, preferably 100 to 310 μmol / g, and more preferably 100 to 300 μmol / g. When the number of OH groups is 100 μmol / g or more, the adhesion to copper foil is improved, and when it is 330 μmol / g or less, the heat resistance and dielectric properties of the board are improved. The number of OH groups in the polyphenylene ether can be measured by the method described in the Examples below.

[0038] The polyphenylene ether has 0.3 to 3.0 OH groups per molecule, preferably 0.8 to 2.8 groups per molecule, and more preferably 1.0 to 2.5 groups per molecule. When the number of OH groups per molecule is 0.3 or more, adhesion to copper foil is improved, and when the number is 3.0 or less, the heat resistance and dielectric properties of the substrate are improved and the production stability of polyphenylene ether can be ensured.

[0039] (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 a monohydric phenol compound represented by the above formula (1) or (2), or a step of oxidative polymerization of a monohydric or polyhydric phenol compound represented by the above formula (1) or (7). The step of carrying out oxidative polymerization preferably involves oxidatively polymerizing a raw material containing at least phenol of the above formula (1) and phenol of the above formula (2), or phenol of the above formula (1) and phenol of the above formula (7).

[0040] 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 preferable since they are inexpensive and easily available. The monohydric phenol compound represented by the above formula (1) may be used alone or in combination of two or more kinds.

[0041] 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 are bulky substituents, are more preferred. The monohydric phenol compound represented by the above formula (2) may be used alone or in combination of two or more kinds.

[0042] 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 preferred because they are particularly inexpensive and easily available.

[0043] 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(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)-1-methylethyl]phenyl]ethylidene]bis(2,6-dimethylphenol). 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 of such phenols 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 preferred because it is particularly inexpensive and easily available. The polyhydric phenol compound represented by the above formula (7) may be used alone or in combination of two or more kinds.

[0044] 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.

[0045] Normally, in the oxidative polymerization of phenols having a hydrogen atom at the ortho position (e.g., 2-methylphenol, 2,5-dimethylphenol, 2-phenylphenol), an ether bond can also be formed 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, and ultimately a gel component that is insoluble in solvents is generated.

[0046] On the other hand, when the phenol represented by the above formula (2) has a bulky substituent at the ortho position on one side, it becomes possible to control the bonding position of the phenol compound during oxidative polymerization, despite the presence of a hydrogen atom 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.

[0047] 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.

[0048] The molecular weight of the polyphenylene ether can be adjusted, for example, by the molar ratio of the structure of the formula (2) to the total of the structure of the formula (1) and the structure of the formula (2), or the molar ratio of the structure of the formula (7) to the total of the structure of the formula (1) and the structure of the formula (7). That is, when the molar ratio of the structure of the formula (2) or the formula (7) is high, the molecular weight (reduced viscosity) can be lowered, and when the molar ratio of the structure of the formula (2) or the formula (7) is low, the molecular weight (reduced viscosity) can be adjusted to be high.

[0049] Here, 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.

[0050] A good solvent for polyphenylene ether is a solvent capable of dissolving polyphenylene ether. 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.

[0051] The polymerization catalyst used may be a known catalyst system that can be generally used for the production of polyphenylene ether.Generally known catalyst systems include those that are composed of a transition metal ion having redox ability and an amine compound that can form a complex with the transition metal ion, such as a catalyst system composed of a copper compound and an amine compound, a catalyst system composed of a manganese compound and an amine compound, or a catalyst system composed 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.

[0052] 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 (10) as the amine compound. [ka] (In formula (10), 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, but are not all hydrogen atoms at the same time. 18 is a linear or methyl-branched alkylene group having 2 to 5 carbon atoms.

[0053] Examples of the copper compound of the catalyst component described herein are listed below. Suitable copper compounds include cuprous compounds, cupric compounds, and mixtures thereof. Examples of cupric compounds include, for example, cupric chloride, cupric bromide, cupric sulfate, and cupric nitrate. Examples of cuprous compounds include, for example, cuprous chloride, cuprous bromide, cuprous sulfate, and cuprous nitrate. Particularly preferred metal compounds among these are cuprous chloride, cupric chloride, cuprous bromide, and cupric bromide. These copper salts may be synthesized at the time of use from oxides (e.g., cuprous oxide), carbonates, hydroxides, and the like and corresponding halogens or acids. A method that is often used is to mix the cuprous oxide exemplified above with hydrogen halide (or a solution of hydrogen halide) to prepare the copper salt.

[0054] 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 an aqueous solution or a solution using a suitable solvent. These halogen compounds can be used alone as a component, or in combination of two or more kinds. Preferred halogen compounds are an aqueous solution of hydrogen chloride and an aqueous solution of hydrogen bromide.

[0055] 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 amount of copper atoms used is preferably in the range of 0.02 to 0.6 moles per 100 moles of the phenol compound added to the polymerization reaction.

[0056] The diamine compound of the catalyst component may, for example, be 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.

[0057] In addition, the polymerization catalyst may contain a primary amine and a secondary monoamine as a component thereof. Examples of the secondary monoamine 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.

[0058] The polymerization catalyst may also contain a tertiary monoamine compound as a component. The tertiary monoamine compound is an aliphatic tertiary amine including an alicyclic tertiary amine. Examples of the tertiary monoamine compound 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 relative to 100 moles of the phenol compound added to the polymerization reaction.

[0059] In this embodiment, there is no limitation on adding a surfactant that has been known to have an effect of improving polymerization activity. Examples of such surfactants include trioctylmethylammonium chloride, known under the trade names Aliquat 336 and Capriquat.

[0060] 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 reduced or increased pressure can be used as necessary.

[0061] 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, the reaction selectivity may decrease or gel may be formed, so it is in the range of 0 to 60°C, preferably 10 to 40°C.

[0062] In the process for producing polyphenylene ether, the polymerization can also be carried out in a poor solvent such as an alcohol.

[0063] In addition, in the method of producing polyphenylene ether, there is no particular restriction on the post-treatment method after the polymerization reaction. Usually, an acid such as hydrochloric acid or acetic acid, or ethylenediaminetetraacetic acid (EDTA) and its salts, nitrilotriacetic acid and its salts, etc. are added to the reaction liquid to deactivate the catalyst. In addition, the method of removing the dihydric phenol by-product generated by the polymerization of polyphenylene ether can be performed using a conventionally known method. If the metal ions, which are the catalyst, are substantially deactivated as described above, the mixture can be decolorized simply by heating it. It is also possible to add a required amount of a known reducing agent. Examples of known reducing agents include hydroquinone and sodium dithionite.

[0064] 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 may be performed into an organic phase and an aqueous phase, and the aqueous phase may be removed to remove the copper catalyst from the organic phase. This liquid-liquid separation step is not particularly limited, and may include methods such as static separation and separation using a centrifuge. In order to promote the liquid-liquid separation, a known surfactant or the like may be used.

[0065] Next, 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.

[0066] The method for volatilizing the solvent contained in the organic phase is not particularly limited, but 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.

[0067] The temperature of 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.

[0068] 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 in particular, a method of increasing the drying temperature is preferable 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 rolling type dryer. This allows the processing amount to be increased, and the productivity to be maintained at a high level.

[0069] The resin composition according to the present embodiment contains the above-mentioned polyphenylene ether, triallyl isocyanurate and / or triallyl cyanurate, and an organic peroxide, and may further contain, if desired, a crosslinking agent other than triallyl isocyanurate and triallyl cyanurate, 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.

[0070] (Trialyl isocyanurate and / or triallyl cyanurate) The resin composition of the present embodiment contains triallyl isocyanurate and / or triallyl cyanurate as a crosslinking agent, which has the ability to initiate or accelerate a crosslinking reaction. The mass ratio of the polyphenylene ether to triallyl isocyanurate and / or triallyl cyanurate (total mass of polyphenylene ether:triallyl isocyanurate, triallyl cyanurate) is preferably 50:50 to 80:20, and more preferably 60:40 to 70:30, from the viewpoints of improving the compatibility of the triallyl isocyanurate and / or triallyl cyanurate with the polyphenylene ether, the coatability of the resin composition, and achieving even better properties of the mounted electronic circuit board.

[0071] (Crosslinking agents other than triallyl isocyanurate and triallyl cyanurate) The resin composition of the present embodiment may contain a crosslinking agent other than triallyl isocyanurate and triallyl cyanurate that has the ability to initiate or accelerate a crosslinking reaction. The crosslinking agent preferably has a number average molecular weight of 4,000 or less. If the number average molecular weight of the crosslinking agent is 4,000 or less, the increase in viscosity of the resin composition can be suppressed, and good resin fluidity can be obtained during heat molding. The number average molecular weight may be a value measured by a general molecular weight measurement method, and specifically, a value measured using GPC can be mentioned.

[0072] In addition, from the viewpoint of crosslinking reaction, the crosslinking agent preferably has an average of two or more carbon-carbon unsaturated double bonds in one molecule. The crosslinking agent may be composed of one type of compound, or may be composed of two or more types of compounds. In this specification, the term "carbon-carbon unsaturated double bond" refers to a double bond located at an end branched from the main chain when the crosslinking agent is a polymer or oligomer. An example of the carbon-carbon unsaturated double bond is a 1,2-vinyl bond in polybutadiene.

[0073] When the number average molecular weight of the crosslinking agent is less than 600, the number (average) of carbon-carbon unsaturated double bonds per molecule of the crosslinking agent is preferably 2 to 4. When the number average molecular weight of the crosslinking agent is 600 or more and less than 1,500, the number (average) of carbon-carbon unsaturated double bonds per molecule of the crosslinking agent is preferably 4 to 26. When the number average molecular weight of the crosslinking agent is 1,500 or more and less than 4,000, the number (average) of carbon-carbon unsaturated double bonds per molecule of the crosslinking agent is preferably 26 to 60. When the number average molecular weight of the crosslinking agent is within the above range, the number of carbon-carbon unsaturated double bonds is the above specific value or more, so that the resin composition of this embodiment has a higher reactivity of the crosslinking agent and a higher crosslink density of the cured product of the resin composition, and as a result, it can be imparted with better heat resistance. On the other hand, when the number average molecular weight of the crosslinking agent is within the above range, the number of carbon-carbon unsaturated double bonds is the above specific value or less, so that it can be imparted with better resin fluidity during hot molding.

[0074] Examples of the crosslinking agent include polyfunctional methacrylate compounds having two or more methacrylic groups in the molecule, polyfunctional acrylate compounds having two or more acrylic groups in the molecule, polyfunctional vinyl compounds having two or more vinyl groups in the molecule such as polybutadiene, vinylbenzyl compounds such as divinylbenzene having a vinylbenzyl group in the molecule, polyfunctional maleimide compounds having two or more maleimide groups in the molecule such as 4,4'-bismaleimide diphenylmethane, polyfunctional acrylates having two or more acrylic groups in the molecule such as tricyclodecane dimethanol diacrylate, and polyfunctional methacrylates having two or more acrylic or methacrylic groups in the molecule such as tricyclodecane dimethanol dimethacrylate. These crosslinking agents may be used alone or in combination of two or more. The crosslinking agent must contain at least one compound selected from among these compounds, triallyl isocyanurate and triallyl cyanurate. By containing at least one compound selected from triallyl isocyanurate and triallyl cyanurate, the resin composition can further improve the compatibility and coatability of the crosslinking agent and polyphenylene ether, and tends to have better board properties when mounted on an electronic circuit board.

[0075] When a crosslinking agent other than triallyl isocyanurate and triallyl cyanurate is contained, the mass ratio of the polyphenylene ether to the crosslinking agent (polyphenylene ether:total mass of crosslinking agents including triallyl isocyanurate, triallyl cyanurate, and other crosslinking agents) is preferably 50:50 to 80:20, and more preferably 60:40 to 70:30, from the viewpoints of compatibility between the crosslinking agent and the polyphenylene ether, coatability of the resin composition, and further excellent properties of the mounted electronic circuit board.

[0076] (organic peroxide) In the resin composition of the present embodiment, in addition to the polyphenylene ether, triallyl isocyanurate and / or triallyl cyanurate, and optionally a crosslinking agent other than triallyl isocyanurate and triallyl cyanurate, any organic peroxide capable of promoting a polymerization reaction can be used. 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. In addition, radical generators such as 2,3-dimethyl-2,3-diphenylbutane can also be used as reaction initiators 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 tangent (and preferably a low dielectric constant).

[0077] The one-minute half-life temperature of the organic peroxide is preferably 155 to 195° C., more preferably 160 to 195° C., and further preferably 165 to 195° C. In this specification, the one-minute half-life temperature is the temperature at which the organic peroxide decomposes and the amount of active oxygen is reduced to half in one minute. The one-minute half-life temperature is a value confirmed by a method in which an organic peroxide is dissolved in a solvent inactive against radicals, such as benzene, to a concentration of 0.05 to 0.1 mol / L, and the organic peroxide solution is thermally decomposed in a nitrogen atmosphere.

[0078] When the polyphenylene ether-containing resin composition is subjected to hot-press molding, the polyphenylene ether is sufficiently melted before the reaction with the crosslinking agent is started, and the moldability tends to be excellent. On the other hand, when the organic peroxide has a one-minute half-life temperature of 195°C or less, the decomposition speed of the organic peroxide is sufficient under normal hot-press molding conditions (e.g., maximum temperature of 200°C), and the crosslinking reaction with the crosslinking agent can be efficiently and slowly proceeded, and a cured product having good electrical properties (especially dielectric tangent) can be formed.

[0079] 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-butylperoxy2-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).

[0080] 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 parts by mass or more, and particularly preferably 1.5 parts by mass or more, based on 100 parts by mass of the polyphenylene ether and the crosslinking agent (total mass of the crosslinking agent including triallyl isocyanurate and triallyl cyanurate), from the viewpoint of increasing 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, based on 100 parts by mass of the polyphenylene ether and the crosslinking agent, from the viewpoint of keeping the dielectric constant and dielectric loss tangent of the obtained cured product low.

[0081] The content of the organic peroxide is preferably 0.1 parts by mass or more and 50 parts by mass or less, more preferably 1.0 parts by mass or more and 25 parts by mass or less, even more preferably 2.0 parts by mass or more and 22.5 parts by mass or less, still more preferably 3.0 parts by mass or more and 21.5 parts by mass or less, and particularly preferably more than 5.0 parts by mass and 20 parts by mass or less, relative to 100 parts by mass of the crosslinking agent. When the content is 0.1 parts by mass or more, the reaction rate tends to be increased, and when the content is 50 parts by mass or less, the dielectric constant and dielectric loss tangent of the obtained cured product tend to be kept low.

[0082] The content of the organic peroxide is preferably 0.1 parts by mass or more and 50 parts by mass or less, more preferably 1.0 parts by mass or more and 25 parts by mass or less, even more preferably 2.0 parts by mass or more and 22.5 parts by mass or less, even more preferably 3.0 parts by mass or more and 21.5 parts by mass or less, and particularly preferably more than 5.0 parts by mass and 20 parts by mass or less, based on 100 parts by mass of the total mass of triallyl isocyanurate and / or triallyl cyanurate. When the content is 0.1 parts by mass or more, the reaction rate tends to be increased, and when the content is 50 parts by mass or less, the dielectric constant and dielectric loss tangent of the obtained cured product tend to be kept low.

[0083] (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 olefin-based alkene compound and its hydrogenated product (a hydrogenated block copolymer obtained by hydrogenating a block copolymer of a vinyl aromatic compound and an olefin-based alkene compound), and a homopolymer of a vinyl aromatic compound. The content of the vinyl aromatic compound-derived unit 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 the vinyl aromatic compound-derived unit in the block copolymer or its hydrogenated product is 20% by mass or more, the compatibility with polyphenylene ether is further improved, and the adhesive strength with the metal foil tends to be further improved.

[0084] The vinyl aromatic compound may have an aromatic ring and a vinyl group in the molecule, and may be, for example, styrene, etc. The olefin-based alkene compound may have a linear or branched structure in the molecule, and may be, for example, ethylene, propylene, butylene, isobutylene, butadiene, 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 copolymers, styrene-ethylene-butadiene block copolymers, styrene-ethylene-butylene block copolymers, styrene-butadiene-butylene block copolymers, styrene-isoprene block copolymers, styrene-ethylene-propylene block copolymers, styrene-isobutylene block copolymers, hydrogenated styrene-butadiene block copolymers, hydrogenated styrene-ethylene-butadiene block copolymers, hydrogenated styrene-butadiene-butylene block copolymers, hydrogenated styrene-isoprene block copolymers, and homopolymers of styrene (polystyrene), and more preferably at least one selected from the group consisting of styrene-butadiene block copolymers, hydrogenated styrene-butadiene block copolymers, and polystyrene.

[0085] The hydrogenation rate in the hydrogenated product is not particularly limited, and some of the carbon-carbon unsaturated double bonds derived from the olefin-based alkene compound may remain.

[0086] The weight average molecular weight of the thermoplastic resin is preferably 10,000 to 300,000, more preferably 20,000 to 290,000, and further preferably 30,000 to 280,000. When the weight average molecular weight is 10,000 or more, the resin composition of the present embodiment tends to have better heat resistance when cured. When the weight average molecular weight is 300,000 or less, the resin composition of the present embodiment tends to have better resin fluidity during heat molding. The weight average molecular weight is determined by the method described in the examples below.

[0087] The content of the thermoplastic resin is preferably 2 to 20 parts by mass, more preferably 3 to 19 parts by mass, further 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 crosslinking agent. When the content is 2 parts by mass or more, the resin composition of the present 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 the present embodiment tends to have even better resin fluidity during hot molding. From the same viewpoint, the content of the thermoplastic resin is preferably 2 parts by mass to 20 parts by mass, more preferably 3 parts by mass to 19 parts by mass, based on 100 parts by mass of the total of polyphenylene ether and crosslinking agent.

[0088] The resin composition of the present embodiment may also contain a thermoplastic resin other than the thermoplastic resin having the type and weight average molecular weight described above.

[0089] (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 incompatible with other components contained in the resin composition after the resin composition is cured from the viewpoint of improving heat resistance. Preferably, the flame retardant is incompatible with polyphenylene ether and / or crosslinking agent in the resin composition after the resin composition is cured. Examples of the flame retardant 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, the flame retardant is preferably decabromodiphenylethane from the viewpoint of compatibility between the flame retardant and polyphenylene ether, coatability of the resin composition, and superior properties of the mounted electronic circuit board.

[0090] 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, relative to 100 parts by mass of the total of the polyphenylene ether resin and the crosslinking agent. Moreover, from the viewpoint of maintaining a low dielectric tangent of the obtained cured product (preferably also maintaining 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.

[0091] (Silica filler) The resin composition of the present embodiment may further contain a silica filler. Examples of the silica filler 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 the polyphenylene ether and the crosslinking agent. The silica filler may be surface-treated with a silane coupling agent or the like.

[0092] 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., in addition to the flame retardant and the silica filler. 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.

[0093] (solvent) The resin composition of the present embodiment may further contain a solvent. From the viewpoint of solubility, the solvent is preferably an aromatic compound such as toluene or xylene, methyl ethyl ketone (MEK), cyclopentanone, cyclohexanone, or chloroform. These solvents may be used alone or in combination of two or more.

[0094] <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.

[0095] <Prepreg> The prepreg of the present embodiment is a composite of a substrate and the resin composition of the present embodiment, and the substrate may be impregnated with or coated with the resin composition of the present 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 with a hot air dryer or the like.

[0096] 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 fully aromatic polyamide fibers, fully 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, craft paper, cotton paper, and cloth obtained from paper-glass mixed fiber yarn; and polytetrafluoroethylene porous films. Among these, glass cloth is preferable. These substrates may be used alone or in combination of two or more.

[0097] 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%. When the proportion is 30 mass% or more, the insulation reliability tends to be more excellent when the prepreg is used for electronic boards, etc. When the proportion is 80 mass% or less, the mechanical properties such as flexural modulus tend to be more excellent in applications such as electronic boards.

[0098] <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 and a metal foil. The metal-clad laminate of this embodiment preferably has a form in which the cured product of the prepreg (hereinafter also referred to as "cured product composite") and the metal foil are laminated and adhered to each other, and is preferably used as a material for electronic boards. Examples of the metal foil include aluminum foil and copper foil, and among these, copper foil is preferred because it has low electrical resistance. The cured product composite to be combined with the metal foil may be one or more sheets, and the metal foil is laminated on one or both sides of the composite depending on the application to process it into a laminate.

[0099] The method for producing the metal-clad laminate of the present embodiment includes, for example, forming a composite (for example, the above-mentioned prepreg) composed of a resin composition and a substrate, layering 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. It is preferable that the printed wiring board is a metal-clad laminate from which at least a part of the metal foil has been removed.

[0100] <Printed wiring board> The printed wiring board of this embodiment is obtained by removing a part of the metal foil 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 heating the prepreg of the present invention described above. The substrate can be the same as that described above for the prepreg. The printed wiring board of this embodiment has excellent copper foil peel strength and toluene resistance by including the resin composition of this embodiment. EXAMPLES

[0101] The present embodiment will be described in more detail below based on examples, but the present embodiment is not limited to the following examples.

[0102] <Polyphenylene ether> (Production example) Production Example 1: Polyphenylene Ether 1 (PPE1) A 40-liter jacketed polymerization vessel equipped with a sparger for introducing an oxygen-containing gas at the bottom of the polymerization vessel, stirring turbine blades, and a baffle, and equipped with a reflux condenser on the vent gas line at the top of the polymerization 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-C 10 ) was added to obtain a homogeneous solution. Next, a pump was used to start dropping a solution of 647.8 g of 2-tert-butyl-5-methylphenol, 2352.3 g of 2,6-dimethylphenol, and 2.35 kg of toluene into the polymerization tank over 35 minutes, and at the same time, dry air was introduced from the sparger at a rate of 31.5 L / min into the polymerization solution from the bottom of the polymerization tank to start polymerization. Dry air was passed through for 240 minutes to obtain a polymerization mixture. The internal temperature was controlled to be 40°C during polymerization. The polymerization mixture (polymerization liquid) at the end of polymerization was in a homogeneous solution state. Then, the dry air flow was stopped, and 38.73 g of tetrasodium ethylenediaminetetraacetate (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 separated into an organic phase and an aqueous phase by liquid-liquid separation. The organic phase was concentrated by a rotary evaporator until the polymer concentration was 30% by mass. The concentrated solution was mixed with methanol such that the mass ratio of methanol to the 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 the 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.

[0103] Production Example 2: Polyphenylene Ether 2 (PPE2) After the polymerization was started, the same operation as in Production Example 1 was carried out except that dry air was passed through for 200 minutes, thereby obtaining polyphenylene ether (PPE2).

[0104] Production Example 3: Polyphenylene Ether 3 (PPE3) A polyphenylene ether (PPE3) was obtained by carrying out the same operation as in Production Example 1, except that a solution of 928.3 g of 2-tert-butyl-5-methylphenol, 2071.7 g of 2,6-dimethylphenol and 2.07 kg of toluene was used for dropping.

[0105] Production Example 4: Polyphenylene Ether 4 (PPE4) A polyphenylene ether (PPE4) was obtained by carrying out the same operation as in Production Example 1, except that a solution of 1096.6 g of 2-tert-butyl-5-methylphenol, 1903.4 g of 2,6-dimethylphenol and 1.90 kg of toluene was used for dropping.

[0106] Production Example 5: Polyphenylene Ether 5 (PPE5) "XYRON S203A" manufactured by Asahi Kasei Corporation was used as PPE5.

[0107] Production Example 6: Polyphenylene Ether 6 (PPE6) A polyphenylene ether (PPE6) was obtained by carrying out the same operation as in Production Example 1, except that a solution of 314.0 g of 2-tert-butyl-5-methylphenol, 2686.0 g of 2,6-dimethylphenol and 2.68 kg of toluene was used for dropping.

[0108] Production Example 7: Polyphenylene Ether 7 (PPE7) A polyphenylene ether (PPE7) was obtained by carrying out the same operation as in Production Example 1, except that a solution of 1417.9 g of 2-tert-butyl-5-methylphenol, 1582.1 g of 2,6-dimethylphenol and 1.58 kg of toluene was used for dropping.

[0109] Production Example 8: Polyphenylene Ether 8 (PPE8) A polyphenylene ether (PPE8) was obtained by carrying out the same operation as in Production Example 1, except that a solution of 1720.3 g of 2-tert-butyl-5-methylphenol, 1279.7 g of 2,6-dimethylphenol and 2.68 kg of toluene was used for dropping.

[0110] Production Example 9: Polyphenylene Ether 9 (PPE9) A 40-liter jacketed polymerization tank equipped with a sparger, stirring turbine blades and baffles for introducing oxygen-containing gas at the bottom of the polymerization tank and a reflux condenser on the vent gas line at the top of the polymerization tank was charged with 2.4 g of cupric oxide, 18.1 g of 47% by mass aqueous hydrogen bromide solution, 5.8 g of di-t-butylethylenediamine, 28.1 g of di-n-butylamine, 85.6 g of butyldimethylamine, 17.9 kg of toluene, 1903.4 g of 2,6-dimethylphenol, and 1096.6 g of 2-tert-butyl-5-methylphenol to obtain a homogeneous solution while blowing nitrogen gas at a flow rate of 17.1 L / min. Next, dry air was introduced into the polymerization tank from the sparger at a rate of 10.5 L / min to start polymerization. Dry air was aerated for 120 minutes to obtain a polymerization mixture. The internal temperature was controlled to be 20°C during polymerization. At the end of the polymerization, the polymerization mixture (polymerization liquid) was in a homogeneous solution state. The dry air flow was stopped, and 25.9 g of tetrasodium ethylenediaminetetraacetate (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 150 minutes, then allowed to stand for 20 minutes, and the organic phase and the aqueous phase were separated by liquid-liquid separation. The organic phase was concentrated by a rotary evaporator until the polymer concentration was 25% by mass. The above solution was mixed with methanol such that the ratio of methanol to polymer solution was 6, and polymer precipitation was performed. Wet polyphenylene ether was obtained by filtration under reduced pressure using a glass filter. Furthermore, the wet polyphenylene ether was washed with an amount of methanol such that the ratio of methanol to wet polyphenylene ether was 3. The above washing operation was performed three times. Next, the wet polyphenylene ether was kept at 140°C and 1 mmHg for 120 minutes, and polyphenylene ether 9 (PPE9) in a dry state was obtained.

[0111] (Analysis of polyphenylene ether) The following analyses were carried out on PPE1 to 9 obtained in the above Production Examples. The analysis results are shown in Table 1.

[0112] (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.

[0113] (2) Number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of polyphenylene ether A gel permeation chromatograph (Shimadzu Corporation, LC-2030C Plus) was used as a measuring device, and a calibration curve was prepared using standard polystyrene and ethylbenzene, and the number average molecular weight (Mn) of the obtained polyphenylene ether was measured using this calibration curve. The standard polystyrenes used had molecular weights of 3,650,000, 2,170,000, 1,090,000, 681,000, 204,000, 52,000, 30,200, 13,800, 3,360, 1,300, and 550. The columns used were two Showa Denko K-805L columns connected in series. The solvent used was chloroform, with a solvent flow rate of 1.0 mL / min and a column temperature of 40°C. A 1 g / L chloroform solution of polyphenylene ether was prepared and used as the measurement sample. The UV wavelength of the detection unit was 254 nm for standard polystyrene and 283 nm for polyphenylene ether. Based on the above measurement data, the number average molecular weight (Mn) (g / mol), weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) were calculated from the peak area ratio based on the curve showing the molecular weight distribution obtained by GPC.

[0114] (3) Number of OH groups in polyphenylene ether 5.0 mg of polyphenylene ether was weighed out. Then, this weighed polyphenylene ether was dissolved in 25 mL of methylene chloride. After adding 150 μL of 2 mass% tetraethylammonium hydroxide (TEAH) ethanol solution to 2.0 mL of the prepared solution, the absorbance (Abs) at 318 nm was measured using a UV spectrophotometer (Hitachi: U-3210 type) (using an absorbance measurement cell with a cell length of 1 cm). Then, based on the measurement results, the number of OH groups obtained from the absorbance was calculated using the following formula (1). Number of OH groups (μmol / g)=[(25×Abs) / (ε×5)]×10 6 Formula (1) (Here, ε is the extinction coefficient, which is 4700 L / mol cm.)

[0115] (4) Number of OH groups per molecule of polyphenylene ether Using the number average molecular weight determined by gel permeation chromatography (details are described in (2) above), the number of OH groups per molecule of polyphenylene ether was calculated according to the following mathematical formula (2). Average number of hydroxyl groups per molecule (groups / molecule) = (number average molecular weight determined using gel permeation chromatography) x (number of OH groups obtained from absorbance) / 10 6 Formula (2)

[0116] (5) Long-term solubility in toluene (TL solubility) 5.0 g of polyphenylene ether and 5.0 g of toluene were weighed into a transparent glass screw tube. They were mixed at 20° C. using a stirrer and a magnetic stirrer. After leaving the mixed solution for one day, the solution was checked and evaluated according to the following criteria. 〇: The solution remains transparent △: Some residual melting remains ×: Clearly not dissolved or a large amount of insoluble matter is present

[0117] [Table 1]

[0118] <Components other than polyphenylene ether> (Trialyl isocyanurate and / or triallyl cyanurate) Triallyl isocyanurate (product name: TAIC, manufactured by Tokyo Chemical Industry Co., Ltd., number average molecular weight: 249.3, number of unsaturated double bonds in the molecule: 3)

[0119] (organic peroxide) Bis(1-tert-butylperoxy-1-methylethyl)benzene (product name: Perbutyl P, manufactured by Nippon Oil & Fats Co., Ltd., 1-minute half-life temperature: 175.4°C)

[0120] (thermoplastic resin) Hydrogenated styrene-based thermoplastic resin (SEBS) (product name: Tuftec H1041, manufactured by Asahi Kasei Corporation, weight average molecular weight: approx. 90,000, styrene unit content: 32% by mass)

[0121] (Flame retardant) Decabromodiphenylethane (product name: SAYTEX8010, manufactured by Albemarle)

[0122] (Filler) Spherical silica (product name: SO-C6, manufactured by Admatechs)

[0123] [Example] As shown below, cured products were prepared from the resin compositions of the respective Examples and Comparative Examples.

[0124] Example 1 According to the composition and solvent shown in Table 2, a thermoplastic resin was added to 205 parts by mass of toluene, stirred and dissolved, and then a flame retardant, spherical silica, and PPE1 synthesized by the above method were added, and stirring was continued until PPE1 was dissolved. Next, triallyl isocyanurate and an organic peroxide were 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, and the cloth was 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, stacked in a predetermined number, and then copper foil (F1N-WS foil, 18 μm thick, manufactured by Furukawa Electric Co., Ltd.) was placed on both sides of the stacked prepregs, followed by vacuum pressing to obtain a copper-clad laminate. In the vacuum pressing process, the temperature was first raised from 30°C to 200°C at a rate of 2°C / min while applying a pressure of 40 kg / cm2, and after the temperature reached 200°C, the pressure was increased to 40 kg / cm2. 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.

[0125] (Examples 2 to 6, Comparative Examples 1 to 5) Except for changing the resin composition as shown in Table 2, a resin composition, a varnish, a prepreg, and a copper-clad laminate were obtained under the same conditions as in Example 1. In addition, in Comparative Example 1 using PPE5 and Comparative Example 2 using PPE6, the PPE did not completely dissolve in toluene, and it was not possible to prepare a prepreg and a copper-clad laminate.

[0126] <Evaluation> The samples obtained in the above Examples and Comparative Examples were evaluated as follows.

[0127] (1) Copper foil peel strength (Peel strength N / mm) of the cured resin composition The stress was measured when the copper foil of the copper-clad laminate was peeled off at a constant speed. The copper-clad laminate using the 18 μm thick copper foil (F1N-WS foil, manufactured by Furukawa Electric Co., Ltd.) obtained in the above-mentioned Examples and Comparative Examples was cut into a size of 10 mm wide x 120 mm long, and the copper foil was peeled off at an angle of 90° to the removal surface at a speed of 50 mm / min using an autograph (AG-I20kN, manufactured by Shimadzu Corporation), and the average load was measured and the average value of three measurements was calculated. The calculated copper foil peel strength of the cured resin composition is preferably 0.39 N / mm or more, more preferably 0.52 N / mm or more, even more preferably 0.55 N / mm or more, and particularly preferably 0.60 N / mm or more, from the viewpoint of preventing peeling of the wiring.

[0128] (2) Toluene immersion test The cured resin compositions obtained in the above-mentioned Examples and Comparative Examples, each having a thickness of about 0.5 mm, were cut into a length of 50 mm and a width of 5 mm, and immersed in a sufficient amount of toluene at 20°C for 24 hours. The mass loss was then evaluated according to the following criteria. ○: When the mass loss before and after immersion is less than 0.5% by mass △: Mass loss before and after immersion is 0.5% by mass or more and less than 1% by mass ×: When the mass loss before and after immersion is 1% or more by mass

[0129] [Table 2]

[0130] As shown in Tables 1 and 2, it was found that PPE1 to 4 have excellent solubility in toluene, and by using them, a resin composition having excellent copper foil peel strength and toluene resistance can be obtained. [Industrial Applicability]

[0131] INDUSTRIAL APPLICABILITY The resin composition containing the polyphenylene ether of the present invention has excellent copper foil peel strength and solvent resistance, and is therefore industrially valuable for use as an electronic material and a modifier.

Claims

1. The copolymer comprises 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): the content of the repeating unit derived from phenol of the following formula (1) is 70 mol % or more and less than 85 mol %, and the content of the repeating unit derived from phenol of the following formula (2) is more than 15 mol % and 30 mol % or less, relative to 100 mol % in total of the repeating units of the following formula (1) and the following formula (2), The molecular weight distribution (Mw / Mn) determined by gel permeation chromatography (GPC) is 2.0 to 6.0; A polyphenylene ether having 0.8 to 2.5 OH groups per molecule. 【Chemistry 1】 (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. 【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 each independently represents a linear alkyl group having 1 to 8 carbon atoms which may be substituted, or two R 31 is a cyclic alkyl structure having 1 to 8 carbon atoms bonded to 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.

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

3. The polyphenylene ether according to claim 1, characterized in that the reduced viscosity (ηsp / c) measured in a chloroform solution having a concentration of 0.5 g / dL at 30° C. is 0.13 to 0.30 dL / g.

4. 2. The polyphenylene ether according to claim 1, characterized in that the number of OH groups per 1 g is 100 to 300 μmol / g.

5. The monohydric phenol compound represented by the formula (1) is 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- 2. The polyphenylene ether according to claim 1, which is one or more selected from the group consisting of 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.

6. The polyphenylene ether according to claim 1, wherein the monohydric phenol compound represented by the formula (2) is one or more selected from the group consisting of 2-isopropyl-5-methylphenol, 2-cyclohexyl-5-methylphenol, 2-tert-butyl-5-methylphenol, and 2-isobutyl-5-methylphenol.

7. The polyphenylene ether according to claim 1 , further comprising a structural unit derived from a phenol represented by the following formula (7): 【Chemistry 4】 In formula (7), X is an arbitrary linking group having a valence of a, a is an integer from 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 positions of the benzene ring to which -O- is bonded, with the carbon atom at the 1st position being the 1st position, and each k is independently an integer of 1 to 4.

8. The phenol represented by the formula (7) is a phenol compound having two phenol units in the molecule selected from the group consisting of 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, or 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(2,6-dimethylphenol), 4,4'-[(3,4-dihydroxyphenyl)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)cyclohexylidene]bis(2,6-dimethylphenol), 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)ethyl]-4-methylphenol, 2,6-bis[(4-hydroxy-2,3,6-trimethylphenol)ethyl] 2,6-bis[(4-hydroxy-3,5,6-trimethylphenyl)methyl]-4-methylphenol, 2,6-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[(4-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], 4,4'-methylenebis[2-[(2,3,4-trihydroxyphenyl)methyl]-3,6-dimethylphenol], 6,6'-methyl 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], 4,4'-cyclohexylidenebis[2-cyclohexyl-6-[(4-hydroxy-2-methyl-5-cyclohexylphenyl)methyl]phenol], 4,a phenol compound having three or more phenol units in the molecule selected from the group consisting of 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, The polyphenylene ether of claim 1 .

9. The polyphenylene ether according to any one of claims 1 to 8, one or more solvents selected from the group consisting of toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, and chloroform; A polyphenylene ether solution comprising:

10. A resin film comprising the polyphenylene ether according to any one of claims 1 to 8.

11. A prepreg, which is a composite of a substrate and the polyphenylene ether according to any one of claims 1 to 8.

12. The prepreg according to claim 11, wherein the base material is a glass cloth.

13. A metal-clad laminate comprising a laminate of the cured resin film according to claim 11 and a metal foil.

14. A metal-clad laminate comprising a cured product of the prepreg according to claim 13 and a metal foil.

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