JP2022117890A - Polyphenylene ether and method for producing the same, and adhesive composition - Google Patents

Abstract

To provide a low-molecular weight polyphenylene ether and a method for producing the same that has excellent solvent solubility and storage stability after dissolution in solvent, and to provide an adhesive composition that contains the polyphenylene ether.SOLUTION: There is provided a polyphenylene ether that has a general formula (1) as a structural unit, a weight average molecular weight (Mw) of less than 2500, (Mw/Mn) of 1.2 to 1.6, a content of molecular weight less than 1000 of 10 mass% or more, and a content of a copper compound of less than 100 mass ppm as a copper element. (In the formula, R1 is an alkyl group, a substituted alkyl group, an aralkyl group, a substituted aralkyl group, an aryl group, a substituted aryl group, an alkoxy group or a substituted alkoxy group, and R2, R3 are a same group as R1, H or a halogen atom.)SELECTED DRAWING: None

Description

The present invention relates to a polyphenylene ether, a method for producing the same, and an adhesive composition.

Polyphenylene ether (PPE) has excellent high-frequency characteristics, flame retardancy, and heat resistance, and is therefore widely used as a material in the fields of electrical/electronics, automobiles, and various other industrial materials. While taking advantage of these characteristics, polyphenylene ether, which has a lower molecular weight and improved solubility in general-purpose solvents, is used as a composite material and additive for electronic material applications and for obtaining excellent characteristics in combination with other resins. Applications and the like are being studied (for example, Patent Document 1).

JP-A-2004-99824

In recent years, there has been a demand for a reduction in dielectric constant and dielectric loss tangent in the high frequency region, and studies have been made on the use of polyphenylene ether, which has excellent dielectric properties, for copper-clad laminates.
In particular, the use of polyphenylene ether has been studied in order to achieve both adhesiveness and low dielectric strength in bonding applications between substrates and copper foils.
However, while polyphenylene ether has excellent dielectric properties, it has the problem of low solubility in solvents and poor storage stability (dissolution stability) after dissolution in solvents. is known to be difficult to

Therefore, the present invention has been made in view of the above problems, a low molecular weight polyphenylene ether excellent in solvent solubility and storage stability after solvent dissolution, a method for producing the same, and an adhesive composition containing the polyphenylene ether The purpose is to provide goods.

（式中、Ｒ１、Ｒ２、Ｒ３は各々独立の置換基を表し、Ｒ１はアルキル基、置換アルキル基、アラルキル基、置換アラルキル基、アリール基、置換アリール基、アルコキシ基、又は置換アルコキシ基であり、Ｒ２、Ｒ３はＲ１について定義されたものと同一の基に加えて更に水素原子又はハロゲン原子であってもよい。）
［２］
分子量５００未満の成分の含有量が４．０質量％以上である、［１］に記載のポリフェニレンエーテル。
［３］
銅化合物の含有量が銅元素として６０質量ｐｐｍ以下である、［１］又は［２］に記載のポリフェニレンエーテル
［４］
メチルエチルケトンに対し、２５℃の雰囲気下で４０質量％以上の飽和溶解度を有する、［１］～［３］のいずれかに記載のポリフェニレンエーテル。
［５］
重合溶媒中で、フェノール化合物を重合触媒と酸素との存在下で重合する、請求項１～４のいずれか一項に記載のポリフェニレンエーテルの方法であり、前記重合溶媒の９０～１００質量％がメタノールであり、前記重合溶媒及び前記フェノール化合物を含む重合液を６０℃で１時間以上加熱する加熱工程と、加熱後の前記重合液を濾過して粗ポリフェニレンエーテル（ａ）を得る濾過工程と、メタノール（ｂ）で前記粗ポリフェニレンエーテル（ａ）を２回以上洗浄する洗浄工程とを含み、前記洗浄工程において、前記メタノール（ｂ）の前記粗ポリフェニレンエーテル（ａ）に対する質量割合（ｂ／ａ）が４．０以上であることを特徴とする、製造方法。
［６］
［１］～［４］のいずれかに記載のポリフェニレンエーテル及び熱硬化性樹脂を含有することを特徴とする、接着剤組成物。
［７］
前記熱硬化性樹脂がエポキシ樹脂である、［６］に記載の接着剤組成物。
［８］
さらに硬化促進剤を含む、［６］又は［７］に記載の接着剤組成物。
［９］
さらに溶剤を含む、［６］～［８］のいずれかに記載の接着剤組成物。 That is, the present invention is as follows.
[1]
A polyphenylene ether having a structural unit derived from a phenolic compound represented by the following general formula (1), having a weight average molecular weight (Mw) of less than 2500, and a ratio of the weight average molecular weight to the number average molecular weight (Mn) (Mw /Mn) is 1.2 to 1.6, the content of components having a molecular weight of less than 1000 is 10 mass% or more, and the content of the copper compound is less than 100 mass ppm as copper element. , polyphenylene ether.

(Wherein, R1, R2, and R3 each represent an independent substituent, and R1 is an alkyl group, substituted alkyl group, aralkyl group, substituted aralkyl group, aryl group, substituted aryl group, alkoxy group, or substituted alkoxy group. , R2, and R3 may be the same groups as those defined for R1, and may also be a hydrogen atom or a halogen atom.)
[2]
The polyphenylene ether according to [1], wherein the content of components having a molecular weight of less than 500 is 4.0% by mass or more.
[3]
The polyphenylene ether [4] according to [1] or [2], wherein the content of the copper compound is 60 mass ppm or less as copper element
The polyphenylene ether according to any one of [1] to [3], having a saturated solubility of 40% by mass or more in an atmosphere of 25° C. in methyl ethyl ketone.
[5]
A process for polyphenylene ethers according to any one of claims 1 to 4, wherein a phenolic compound is polymerized in the presence of a polymerization catalyst and oxygen in a polymerization solvent, wherein 90 to 100% by weight of the polymerization solvent is A heating step of heating a polymerization liquid that is methanol and contains the polymerization solvent and the phenol compound at 60 ° C. for 1 hour or more, and a filtration step of filtering the polymerization liquid after heating to obtain a crude polyphenylene ether (a); and a washing step of washing the crude polyphenylene ether (a) with methanol (b) two or more times, wherein the mass ratio (b/a) of the methanol (b) to the crude polyphenylene ether (a) in the washing step is 4.0 or more.
[6]
An adhesive composition comprising the polyphenylene ether according to any one of [1] to [4] and a thermosetting resin.
[7]
The adhesive composition according to [6], wherein the thermosetting resin is an epoxy resin.
[8]
The adhesive composition according to [6] or [7], further comprising a curing accelerator.
[9]
The adhesive composition according to any one of [6] to [8], further comprising a solvent.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a low-molecular-weight polyphenylene ether excellent in solvent solubility and storage stability after dissolution in a solvent, a method for producing the same, and an adhesive composition containing the polyphenylene ether.

EMBODIMENT OF THE INVENTION Hereinafter, the form (henceforth "this embodiment") for implementing this invention is demonstrated in detail. The following embodiments are exemplifications for explaining the present invention, and the present invention is not limited only to these embodiments, and the present invention can be appropriately modified within the scope of the gist thereof. can be implemented.
In the embodiment of the present invention, A (numerical value) to B (numerical value) mean A or more and B or less.

（式中、Ｒ１、Ｒ２、Ｒ３は各々独立の置換基を表し、Ｒ１はアルキル基、置換アルキル基、アラルキル基、置換アラルキル基、アリール基、置換アリール基、アルコキシ基、又は置換アルコキシ基であり、Ｒ２、Ｒ３はＲ１について定義されたものと同一の基に加えて更に水素原子又はハロゲン原子であってもよい。）
上記特徴を有することにより、本実施形態のポリフェニレンエーテルは、優れた高周波特性、難燃性、耐熱性を活かしつつ、汎用溶剤等への溶解性にも優れる。 <Polyphenylene ether>
The polyphenylene ether of the present embodiment has a weight average molecular weight (Mw) of less than 2500, a ratio (Mw/Mn) of the weight average molecular weight to the number average molecular weight (Mn) of 1.2 to 1.6, and a molecular weight of 1000. Polyphenylene having a content of less than 10% by mass or more, a content of a copper compound of less than 100 ppm by mass as copper element, and a structural unit derived from a phenol compound represented by the following general formula (1) is ether.

(Wherein, R1, R2, and R3 each represent an independent substituent, and R1 is an alkyl group, substituted alkyl group, aralkyl group, substituted aralkyl group, aryl group, substituted aryl group, alkoxy group, or substituted alkoxy group. , R2, and R3 may be the same groups as those defined for R1, and may also be a hydrogen atom or a halogen atom.)
By having the above characteristics, the polyphenylene ether of the present embodiment is excellent in solubility in general-purpose solvents and the like while taking advantage of excellent high-frequency characteristics, flame retardancy, and heat resistance.

（式（３）中、Ｒ４、Ｒ５、Ｒ６、Ｒ７は各々独立の置換基を表す。Ｒ４は、炭素数１～７のアルキル基、フェニル基、トリル基、炭素数１～７の置換アルキル基、ハロフェニル基、アルコキシ基、及び少なくとも２個の炭素原子がハロゲン原子と酸素原子とを隔てているハロアルコキシ基からなる群より選択される。Ｒ５、Ｒ６は、水素原子、ハロゲン原子、炭素数１～７のアルキル基、フェニル基、トリル基、炭素数１～７の置換アルキル基、ハロフェニル基、アルコキシ基、及び少なくとも２個の炭素原子がハロゲン原子と酸素原子とを隔てているハロアルコキシ基からなる群より選択される。Ｒ７は水素原子である。） Polyphenylene ether of the present embodiment is obtained by polymerizing a phenolic compound represented by the following general formula (3), having a structural unit derived from the phenolic compound represented by the following general formula (3), a homopolymer and/or a copolymer.

(In Formula (3), R4, R5, R6, and R7 each represent an independent substituent. R4 is an alkyl group having 1 to 7 carbon atoms, a phenyl group, a tolyl group, or a substituted alkyl group having 1 to 7 carbon atoms. , a halophenyl group, an alkoxy group, and a haloalkoxy group in which at least two carbon atoms separate the halogen atom and the oxygen atom, wherein R5 and R6 are a hydrogen atom, a halogen atom, and a carbon number of 1 -7 alkyl groups, phenyl groups, tolyl groups, substituted alkyl groups having 1 to 7 carbon atoms, halophenyl groups, alkoxy groups, and haloalkoxy groups in which at least two carbon atoms separate the halogen atom from the oxygen atom; and R7 is a hydrogen atom.)

In formula (3), the halogen atoms represented by R5 and R6 include fluorine, chlorine and bromine atoms, with chlorine and bromine atoms being preferred.

In formula (3), the alkyl group having 1 to 7 carbon atoms represented by R4, R5, and R6 preferably has 1 to 6 carbon atoms, more preferably 1 to 3, linear or branched an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, etc.; is preferred, and a methyl group is more preferred.

In formula (3), the alkyl groups having 1 to 7 carbon atoms represented by R4, R5 and R6 may be substituted with one or more substituents at substitutable positions.
Examples of such substituents include halogen atoms (e.g., fluorine atom, chlorine atom, bromine atom, etc.), alkyl groups having 1 to 6 carbon atoms (e.g., methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, etc.), aryl group (eg, phenyl group, naphthyl group, etc.), alkenyl group (eg, ethenyl group, 1-propenyl group, 2-propenyl group) groups, etc.), alkynyl groups (e.g., ethynyl group, 1-propynyl group, 2-propynyl group, etc.), aralkyl groups (e.g., benzyl group, phenethyl group, etc.), alkoxy groups (e.g., methoxy group, ethoxy group, etc.), An amino group and the like can be mentioned.

Examples of the phenol compound represented by the general formula (3) include o-cresol, 2,6-dimethylphenol, 2-ethylphenol, 2-methyl-6-ethylphenol, 2,6-diethylphenol, 2 -n-propylphenol, 2-ethyl-6-n-propylphenol, 2-methyl-6-chlorophenol, 2-methyl-6-bromophenol, 2-methyl-6-isopropylphenol, 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-phenylphenol, 2,6-diphenylphenol, 2,6-bis-(4-fluorophenyl)phenol, 2-methyl-6-tolylphenol, 2,6-ditolylphenol, 2,5- dimethylphenol, 2,3,6-trimethylphenol, 2,5-diethylphenol, 2-methyl-5-ethylphenol, 2-ethyl-5-methylphenol, 2-allyl-5-methylphenol, 2,5- diallylphenol, 2,3-diethyl-6-n-propylphenol, 2-methyl-5-chlorophenol, 2-methyl-5-bromophenol, 2-methyl-5-isopropylphenol, 2-methyl-5-n -propylphenol, 2-ethyl-5-bromophenol, 2-methyl-5-n-butylphenol, 2,5-di-n-propylphenol, 2-ethyl-5-chlorophenol, 2-methyl-5-phenyl Phenol, 2,5-diphenylphenol, 2,5-bis-(4-fluorophenyl)phenol, 2-methyl-5-tolylphenol, 2,5-ditolylphenol, 2,6-dimethyl-3-allylphenol , 2,3,6-triallylphenol, 2,3,6-tributylphenol, 2,6-di-n-butyl-3-methylphenol, 2,6-di-t-butyl-3-methylphenol, 2,6-dimethyl-3-n-butylphenol, 2,6-dimethyl-3-t-butylphenol and the like.

Among the phenol compounds represented by the general formula (3), 2,6-dimethylphenol, 2,6-diethylphenol, 2,6-diphenylphenol, 2,6-diethylphenol, 2,6-diethylphenol, 2,6-diethylphenol, 2,6-diethylphenol, 2,6-diethylphenol, 2,6-diethylphenol, 3,6-trimethylphenol and 2,5-dimethylphenol are preferred, and 2,6-dimethylphenol and 2,3,6-trimethylphenol are more preferred.
In addition, the phenol compound represented by the general formula (3) may be used alone or in combination of two or more.
For example, a method using a combination of 2,6-dimethylphenol and 2,6-diethylphenol, a method using a combination of 2,6-dimethylphenol and 2,6-diphenylphenol, 2,3,6-trimethyl Examples include a method of using a combination of phenol and 2,5-dimethylphenol, a method of using a combination of 2,6-dimethylphenol and 2,3,6-trimethylphenol, and the like. At this time, the mixing ratio of the phenol compounds to be combined can be arbitrarily selected.

In addition, the phenol compounds used contain small amounts of m-cresol, p-cresol, 2,4-dimethylphenol, 2,4,6-trimethylphenol, etc., which may be contained as by-products during production. good too.

（式（４）中、Ｒ_９、Ｒ_１０、Ｒ_１１、及びＲ_１２は、それぞれ独立して、水素原子、ハロゲン原子、炭素数１～７のアルキル基、フェニル基、ハロアルキル基、アミノアルキル基、炭化水素オキシ基、及び少なくとも２個の炭素原子がハロゲン原子と酸素原子とを隔てているハロ炭化水素オキシ基からなる群より選択される。式（４）中、Ｘは、単結合、２価のヘテロ原子、及び炭素数１～１２の２価の炭化水素基からなる群より選択される。） In the present embodiment, the polyphenylene ether is obtained by copolymerizing a phenol compound represented by the general formula (3) and a divalent phenol compound represented by the following general formula (4), and is obtained by the following general formula ( It may have a structural unit derived from a divalent phenol compound represented by 4).
A dihydric phenol compound represented by the following general formula (4) includes a corresponding monohydric phenol compound, aldehydes (e.g., formaldehyde), ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, cyclohexanone, etc.), a reaction with a dihalogenated aliphatic hydrocarbon, or a reaction between corresponding monohydric phenol compounds.

(In Formula (4), R ₉ , R ₁₀ , R ₁₁ and R ₁₂ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 7 carbon atoms, a phenyl group, a haloalkyl group, an aminoalkyl group , hydrocarbonoxy groups, and halohydrocarbonoxy groups in which at least two carbon atoms separate the halogen and oxygen atoms, wherein X is a single bond, 2 selected from the group consisting of a valent heteroatom and a divalent hydrocarbon group having 1 to 12 carbon atoms.)

Specifically, the divalent phenol compound represented by the general formula (4) includes, for example, the following general formulas (4-a), (4-b), and (4-c). compounds and the like.

In formula (4-a), formula (4-b), and formula (4-c), R ₉ , R ₁₀ , R ₁₁ , and R ₁₂ each independently represent a hydrogen atom, a halogen atom, or a carbon number of 1 selected from the group consisting of -7 alkyl groups, phenyl groups, haloalkyl groups, aminoalkyl groups, hydrocarbonoxy groups, and halohydrocarbonoxy groups in which at least two carbon atoms separate the halogen and oxygen atoms; be.
In formula (4-a), formula (4-b), and formula (4-c), X is a group consisting of a single bond, a divalent heteroatom, and a divalent hydrocarbon group having 1 to 12 carbon atoms. is selected from

Typical compounds represented by general formulas (4-a), (4-b), and (4-c) above include methyl groups for R ₉ and R ₁₀ and hydrogen for R ₁₁ and R ₁₂ . A compound in which X directly connects both aryl groups; a compound in which R ₉ and R ₁₀ are methyl groups, R ₁₁ and R ₁₂ are hydrogen atoms, and X is a methylene group; R ₉ and R ₁₀ are compounds in which R ₁₁ and R ₁₂ are hydrogen atoms and X is a thio group; compounds in which R ₉ , R ₁₀ and R ₁₁ are methyl groups, R ₁₂ is a hydrogen atom and X is an ethylene group; a compound in which _R9 and R10 are methyl groups, R11 and _R12 are hydrogen atoms, and _X is isopropylidene group _{; R9} and _R10 are methyl groups, R11 and _R12 are hydrogen atoms, and _X is a cyclohexylidene group; a compound in which R ₉ , R ₁₀ and R ₁₁ are methyl groups, R ₁₂ is a hydrogen atom, and X directly connects both aryl groups; R ₉ , R ₁₀ and R ₁₁ is a methyl group, R ₁₂ is a hydrogen atom, and X is a methylene group; R ₉ , R ₁₀ and R ₁₁ are a methyl group, R ₁₂ is a hydrogen atom, and X is an ethylene group; R ₉ , R ₁₀ and R ₁₁ are methyl groups, R ₁₂ is a hydrogen atom, and X is a thio group; R ₉ , R ₁₀ and R ₁₁ are methyl groups, R ₁₂ is a hydrogen atom, and X is isopropylidene a compound in which R ₉ , R ₁₀ , R ₁₁ and R ₁₂ are a methyl group and X is a methylene group; a compound in which R ₉ , R ₁₀ , R ₁₁ and R ₁₂ are a methyl group and X is an ethylene group Certain compounds; including but not limited to compounds in which R ₉ , R ₁₀ , R ₁₁ and R ₁₂ are methyl groups and X is isopropylidene group.

When copolymerizing with a dihydric phenol compound represented by the general formula (4), the amount of the dihydric phenol compound of the general formula (4) relative to the monohydric phenol compound described in the general formula (3) is particularly limited. However, it is preferably 0.1 to 30 mol % with respect to 100 mol % of the monohydric phenol compound of general formula (3).

Furthermore, in the present embodiment, the polyphenylene ether is obtained by copolymerization of the phenol compound represented by the general formula (3) and a polyhydric phenol compound, and may have a structural unit derived from the polyhydric phenol compound. is.
Examples of polyhydric phenol compounds include compounds having 3 or more but less than 9 phenolic hydroxyl groups in the molecule and having alkyl groups or alkylene groups at the 2- and 6-positions of at least one of the phenolic hydroxyl groups. are mentioned.

Examples of polyhydric phenol compounds are listed below. 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)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-dimethyl Phenyl)ethyl]-4-methylphenol, 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) (l)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], 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], 4,4′-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 the like, but are not limited thereto.

The number of phenolic hydroxyl groups in the polyhydric phenol compound is not particularly limited as long as it is 3 or more. More preferably, the number is 3-4.
Moreover, a methyl group is preferable as the 2,6-position alkyl group or alkylene group in the polyhydric phenol compound.

Most preferred polyhydric phenol compounds are 4,4′-[(4-hydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4′-[(3-hydroxyphenyl)methylene]bis(2, 6-dimethylphenol), 4,4′-[(4-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 4,4′-[(3-hydroxyphenyl)methylene]bis(2, 3,6-trimethylphenol), 4,4′,4″,4′″-(1,4-phenylenedimethylidene)tetrakis(2,6-dimethylphenol).

The weight average molecular weight (Mw) of the polyphenylene ether of this embodiment is less than 2,500, preferably 1,000 to 2,400, more preferably 1,500 to 2,000. When the weight average molecular weight (Mw) is less than 2,500, solubility in general-purpose solvents (eg, toluene, dichloromethane, methyl ethyl ketone, etc.) and miscibility with other resins can be enhanced.
The weight-average molecular weight (Mw) is the value measured by the measurement method in Examples described later.
The method for controlling the weight average molecular weight (Mw) is not particularly limited. For example, when polymerization is performed in a slurry state (hereinafter also referred to as "slurry polymerization method"), the polymerization time is The weight average molecular weight (Mw) can be controlled to be small by shortening, lengthening the addition time of the monomer, or increasing the ratio of the solvent having a high poor solvent property.

The ratio (Mw/Mn) of the weight average molecular weight to the number average molecular weight (Mn) of the polyphenylene ether of the present embodiment is 1.2 to 1.6, more preferably 1.3 to 1.5. The ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) is 1.2 to 1.6, so that it can be used for general purposes while effectively utilizing the excellent high frequency characteristics, flame retardancy, and heat resistance as a polyphenylene ether resin. Solubility in a solvent and fluidity when dissolved can be improved. In addition, when the ratio of the weight average molecular weight to the number average molecular weight (Mw/Mn) is 1.2 or more, it is possible to reduce the amount of oligomers that are discarded as loss polymers during washing, thereby facilitating industrial production. tend to be able. When the ratio (Mw/Mn) of the weight average molecular weight to the number average molecular weight is 1.6 or less, the ratio of the high molecular weight component is reduced, and the solubility and fluidity in general-purpose solvents tend to be improved. .
The ratio of weight average molecular weight to number average molecular weight (Mw/Mn) is also generally referred to as molecular weight distribution. The molecular weight distribution (Mw/Mn) is the value measured by the measurement method in Examples described later.
The method for controlling the ratio of the weight average molecular weight to the number average molecular weight (Mw/Mn) is not particularly limited. For example, the polyphenylene ether is polymerized by slurry polymerization to reduce Mw/Mn, It can be controlled by, for example, increasing Mw/Mn by using a solution polymerization method.

In the polyphenylene ether of the present embodiment, the content of low molecular weight components having a molecular weight of less than 1000 is 10% by mass or more, preferably 13% by mass or more, and more preferably 15% by mass or more. When the content of low-molecular-weight components having a molecular weight of less than 1,000 is 10% by mass or more, the content of high-molecular-weight components becomes lower, and the solubility in solvents and fluidity during dissolution can be enhanced.
Also, the content of low-molecular-weight components having a molecular weight of less than 1,000 is preferably 30% by mass or less, more preferably 25% by mass or less. When the content of low-molecular-weight components having a molecular weight of less than 1,000 is 30% by mass or less, a polyphenylene ether having an excellent balance between heat resistance, fluidity, and solvent solubility can be obtained.

In addition to the above, the polyphenylene ether of the present embodiment has a content of a low molecular weight component (oligomer component) having a molecular weight of less than 500 from the viewpoint of more effectively increasing the solubility in a solvent. is preferred, more preferably 5.0% by mass or more, and still more preferably 6.0% by mass or more. When the content of low-molecular-weight components (oligomer components) having a molecular weight of less than 500 is 4.0% by mass or more, the content of high-molecular-weight components is further reduced, and the solubility in solvents and fluidity during dissolution are improved. can be done.
Also, the content of low-molecular-weight components having a molecular weight of less than 500 is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. When the content of low-molecular-weight components having a molecular weight of less than 500 is 20% by mass or less, a polyphenylene ether having an excellent balance between heat resistance and fluidity/solvent solubility can be obtained.

Regarding the polyphenylene ether of the present embodiment, the above molecular weight is a polystyrene equivalent molecular weight and can be measured by gel permeation chromatography (GPC). Also, the content of the high-molecular-weight component and the low-molecular-weight component can be calculated from the peak area ratio based on the curve showing the molecular weight distribution obtained by GPC. More specifically, the polystyrene-equivalent molecular weight of polyphenylene ether and the content of high-molecular-weight components and low-molecular-weight components can be determined by the methods described in Examples below.

In the method for producing polyphenylene ether of the present embodiment, the method for controlling the content of low molecular weight components having a molecular weight of less than 1000 and low molecular weight components having a molecular weight of less than 500 (oligomer components) to specific contents is not particularly limited. For example, by increasing the ratio of the poor solvent in the polymerization solvent or washing solvent, by shortening the polymerization time or by lowering the polymerization temperature, low molecular weight components with a molecular weight of less than 1000 and low molecular weight components with a molecular weight of less than 500 are contained. A method of increasing the amount and the like can be mentioned.

In the polyphenylene ether of the present embodiment, the content of the copper compound remaining in the polyphenylene ether even after purification of the polyphenylene ether is less than 100 mass ppm as copper element from the viewpoint of improving the solubility stability in the solvent, It is preferably 60 ppm by mass or less, more preferably 10 ppm by mass or less, and is particularly preferably not contained as much as possible. When the content of the remaining copper compound is within this range, the storage stability of the polyphenylene ether dissolved in the solvent can be enhanced.
The content of the copper compound remaining in the polyphenylene ether can be quantified by inorganic elemental analysis, and specifically, it can be determined by the method described in the examples below.

The polyphenylene ether of the present embodiment has improved solubility in the solvent by containing the low-molecular weight component in the above range, and the solubility stability in the solvent is improved by reducing the residual copper compound to the above range. . Specifically, it preferably has a saturated solubility of 40% by mass or more in an atmosphere of 25° C. in methyl ethyl ketone.
Here, "saturated solubility" means the maximum concentration at which PPE does not exist as an insoluble matter in the solvent. Specifically, the saturated solubility can be measured by the method described in Examples.

<Adhesive composition>
The adhesive composition of the present embodiment contains the polyphenylene ether of the present embodiment described above and a thermosetting resin (A). Furthermore, it may contain a curing accelerator (B). Moreover, if necessary, additives such as a curing catalyst, a heat stabilizer, and a flame retardant may be contained within a range that does not impair the effects of the present invention.
The content of polyphenylene ether in 100% by mass of the adhesive composition is preferably 10 to 60% by mass, more preferably 20 to 40% by mass. When the content of the polyphenylene ether is within the above range, there is a tendency that toughness during curing can be improved without deteriorating compatibility with the thermosetting resin (A) during preparation of the varnish described later.
Each component will be described below.

(Thermosetting resin (A))
The thermosetting resin (A) used in the present embodiment is not particularly limited, but epoxy resins, polyimide resins, bismaleimide triazine resins, phenolic resins, bismaleimides, cyanate esters, and polybutadiene or similar compounds thereof. , and vinyl compounds represented by triallyl isocyanurate, styrene, divinylbenzene, and the like. Each of the above resins may be used alone, or two or more thereof may be used in combination. Among these, epoxy resins are preferred because of their good heat resistance and electrical properties.

As mentioned above, the thermosetting resin (A) is preferably an epoxy resin. Although not particularly limited, examples of epoxy resins include alicyclic epoxy compounds, bisphenol A type epoxy compounds, bisphenol A novolac type epoxy compounds, bisphenol F type epoxy compounds, bisphenol F novolac type epoxy compounds, phenol novolac type epoxy compounds, Cresol novolac type epoxy compounds, naphthalene type epoxy compounds, biphenyl type epoxy compounds, and the like can be mentioned. These may be used individually by 1 type, or may be used in combination of 2 or more type.
The epoxy resin preferably contains a curing agent. Although not particularly limited, examples of curing agents include aliphatic polyamines, polyaminoamides, polymercaptans, aromatic polyamines, acid anhydrides, phenol novolak compounds, dicyandiamide, cyanate ester compounds, and the like. These may be used individually by 1 type, or may be used in combination of 2 or more type.

The content of the thermosetting resin (A) in 100% by mass of the adhesive composition is preferably 40-90% by mass, more preferably 60-80% by mass. When the content of the thermosetting resin (A) is within the above range, it tends to be possible to prepare the varnish described later at a low temperature while maintaining the toughness of the cured product.

(Curing accelerator (B))
The curing accelerator (B) used in the present embodiment is not particularly limited, but examples thereof include tertiary amine compounds, tertiary amine compound salts, imidazole compounds, phosphine compounds, phosphonium compound salts and the like. These may be used individually by 1 type, or may be used in combination of 2 or more type.

The content of the curing accelerator (B) in 100% by mass of the adhesive composition is preferably 0 to 10% by mass, more preferably 0.1 to 5.0% by mass. When the content of the curing accelerator (B) is within the above range, it tends to be possible to obtain a cured product with excellent adhesive strength.

(Additive)
The adhesive composition of the present embodiment may optionally contain components other than those described above, such as a curing catalyst, a diluent, a filler, a pigment, a dye, a flow control agent, a thickener, a reinforcing agent, and a release agent. agents, wetting agents, stabilizers such as heat stabilizers, flame retardants, surfactants, organic solvents, conductive fine particles, crystalline alcohols, other resins other than the above polyphenylene ether and thermosetting resin (A), etc. can further include
Each of the above additives may be used singly or in combination of two or more.
The content of the additive in 100% by mass of the adhesive composition is preferably 20% by mass or less.

The adhesive composition of the present embodiment can be prepared and used as a varnish.
The solvent to be used is not particularly limited as long as it dissolves the resin composition containing polyphenylene ether and thermosetting resin (A) and, if necessary, curing accelerator (B) and additives. MEK, toluene, Chloroform, xylene and the like can be mentioned.

The method for preparing the varnish is not particularly limited, and includes, for example, the following methods.
A thermosetting resin (A) and, if necessary, a curing accelerator (B) are added to a solution obtained by dissolving the polyphenylene ether of the present embodiment in a solvent, and the mixture is stirred until they are dissolved. Furthermore, if necessary, the above-mentioned additives are blended. When dissolving each component, it may be heated in order to improve the solubility.

[Method for producing polyphenylene ether]
The method for producing the polyphenylene ether of the present embodiment is not particularly limited, but is a method of polymerizing a phenol compound in the presence of a polymerization catalyst and oxygen in a polymerization solvent. A heating step of heating a polymerization solution in which mass% is methanol and containing the polymerization solvent and the phenol compound at 60 ° C. for 1 hour or more, and filtering the polymerization solution after heating to obtain a crude polyphenylene ether (a). and a washing step of washing the crude polyphenylene ether (a) with methanol (b) two or more times, wherein in the washing step, the mass ratio of the methanol (b) to the crude polyphenylene ether (a) (b A method in which /a) is 4.0 or more is particularly preferred.

[[Polymerization step]]
In the method for producing polyphenylene ether of the present embodiment, it is preferable to use an alcohol solvent as the polymerization solvent in the polymerization step. By using an alcohol solvent in the polymerization step, the solvent hardly remains in the obtained polyphenylene ether, and volatile components can be reduced. On the other hand, in the polyphenylene ether polymerization step, instead of the alcohol solvent as the polymerization solvent, for example, when an aromatic hydrocarbon having a relatively high affinity with the polyphenylene ether is used, the solvent in the resulting polyphenylene ether is It is difficult to remove sufficiently and can lead to high residual volatiles.

In the method for producing polyphenylene ether of the present embodiment, it is preferable not to use a good solvent for polyphenylene ether as the polymerization solvent in the polymerization step. Here, the good solvent for polyphenylene ether is a solvent capable of dissolving polyphenylene ether. ), aromatic hydrocarbons such as ethylbenzene and styrene; halogenated hydrocarbons such as chloroform, methylene chloride, 1,2-dichloroethane, chlorobenzene and dichlorobenzene; and nitro compounds such as nitrobenzene. In addition, although it has some poor solvent properties, it is classified as a good solvent, pentane, hexane, heptane, cyclohexane, cycloheptane and other aliphatic hydrocarbons; ethyl acetate, ethyl formate and other esters. Ethers such as tetrahydrofuran and diethyl ether; dimethyl sulfoxide and the like are exemplified.

In the method for producing polyphenylene ether of the present embodiment, it is preferable to use a solvent consisting only of an alcohol solvent as the polymerization solvent in the polymerization step. It may be contained in an amount of not more than 5% by mass, preferably not more than 5% by mass. The poor solvent for polyphenylene ether means a solvent that does not dissolve polyphenylene ether at all or can slightly dissolve polyphenylene ether, such as ethers and ketones.

In the method for producing polyphenylene ether of the present embodiment, it is preferable to use, as the polymerization solvent, one containing at least one type of alcohol solvent having 1 to 10 carbon atoms, and at least one type of alcohol solvent having 1 to 10 carbon atoms. What consists of is more preferable.
As the alcoholic solvent having 1 to 10 carbon atoms, methanol, ethanol, propanol, butanol, pentanol, hexanol and the like are preferable, and methanol is more preferable. Among them, the alcohol solvent preferably contains 50 to 100% by mass of methanol and 0 to 50% by mass of alcohol having 2 to 10 carbon atoms in 100% by mass of the alcohol solvent.

The polymerization solvent used in the present embodiment preferably contains 90 to 100% by mass, more preferably 95 to 100% by mass of methanol based on 100% by mass of the polymerization solvent.

As the polymerization catalyst used in the method for producing polyphenylene ether of the present embodiment, a known catalyst system that can be generally used for producing polyphenylene ether can be used. As a generally known catalyst system, one comprising a transition metal ion having oxidation-reduction ability and an amine compound capable of forming a complex with the transition metal ion is known. For example, it comprises a copper compound and an amine compound. These include a catalyst system, a catalyst system comprising a manganese compound and an amine compound, a catalyst system comprising a cobalt compound and an amine compound, and the like. Since the polymerization reaction proceeds efficiently under slightly alkaline conditions, some alkali or additional amine compounds may be added here.

The polymerization catalyst preferably used in the present embodiment is a catalyst comprising a copper compound, a halogen compound, and an amine compound substantially free of primary amines and secondary monoamines as constituent components of the catalyst, and more preferably. is a catalyst containing a diamine compound represented by general formula (5) as an amine compound.

（式中、Ｒ_１３、Ｒ_１４、Ｒ_１５、Ｒ_１６は、それぞれ独立に、水素原子、炭素数１～６の直鎖状または分岐状アルキル基であり、全てが同時に水素原子ではない。Ｒ_１７は、炭素数２～５の直鎖状またはメチル分岐を持つアルキレン基である。）

(In the formula, R ₁₃ , R ₁₄ , R ₁₅ and R ₁₆ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and not all of them are hydrogen atoms at the same time. ₁₇ is a linear or methyl-branched alkylene group having 2 to 5 carbon atoms.)

Examples of copper compounds of the catalyst component are listed here. Suitable copper compounds may be cuprous compounds, cupric compounds or mixtures thereof. Examples of cupric compounds include cupric chloride, cupric bromide, cupric sulfate, and cupric nitrate. Examples of cuprous compounds include cuprous chloride, cuprous bromide, cuprous sulfate, and cuprous nitrate. Among these, particularly preferred copper compounds are cuprous chloride, cupric chloride, cuprous bromide and cupric bromide. These copper salts may also be synthesized at the time of use from oxides (eg, cuprous oxide), carbonates, hydroxides, etc. and the corresponding halogens or acids. A frequently used method is a method of mixing cuprous oxide and hydrogen halide (or a solution of hydrogen halide) as exemplified above. These copper compounds may be used singly or in combination of two or more.

Halogen compounds as catalyst components include, for example, hydrogen chloride, hydrogen bromide, hydrogen iodide, sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide, tetramethylammonium chloride, bromide tetramethylammonium, tetramethylammonium iodide, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide and the like. Moreover, these can be used as an aqueous solution or a solution using a suitable solvent. These halogen compounds may be used singly or in combination of two or more. Preferred halogen compounds are aqueous solutions of hydrogen chloride and hydrogen bromide.

The amount of the copper compound and the halogen compound to be used is not particularly limited, but the amount of the halogen compound to be used is preferably 2 to 20 times the molar amount of the copper atom in terms of halogen atoms. In addition, the amount of the copper compound used is preferably 0.02 to 1.0 mol, more preferably 0.02 to 0.5 mol, more preferably 0.02 to 0.0 mol as a copper atom per 100 mol of the phenol compound. .1 mol.

Next, examples of diamine compounds as catalyst components are listed. For example, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylpropanediamine, 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-propyl Ethylenediamine, 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, N,N,N',N '-tetramethyl-1,5-diaminopentane and the like. A preferred diamine compound for this embodiment has 2 or 3 carbon atoms in the alkylene group connecting the two nitrogen atoms. These diamine compounds may be used singly or in combination of two or more.
The amount of these diamine compounds to be used is not particularly limited, but is preferably 1.0 to 5.0 mol per 100 mol of the phenol compound.

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

In the present embodiment, it is preferable that substantially no primary amines or secondary monoamines are contained as constituent components of the polymerization catalyst. Examples of secondary monoamines include, but are not limited to, dimethylamine, diethylamine, di-n-propylamine, di-i-propylamine, di-n-butylamine, di-i-butylamine, Di-t-butylamine, dipentylamines, dihexylamines, dioctylamines, didecylamines, dibenzylamines, methylethylamine, methylpropylamine, methylbutylamine, cyclohexylamine, N-phenylmethanolamine, N-phenylethanolamine , N-phenylpropanolamine, N-(m-methylphenyl)ethanolamine, N-(p-methylphenyl)ethanolamine, N-(2′,6′-dimethylphenyl)ethanolamine, N-(p-chlorophenyl ) ethanolamine, N-ethylaniline, N-butylaniline, N-methyl-2-methylaniline, N-methyl-2,6-dimethylaniline, diphenylamine and the like.
"Substantially free" with respect to primary amines and secondary monoamines means that they may be contained to the extent that the effects of the polyphenylene ether of the present embodiment are not impaired. Specifically, it is preferably in the range of 1 mol or less per 100 mol of the phenol compound, more preferably in the range of 0.5 mol or less per 100 mol of the phenol compound. It means that it does not contain any primary amines or secondary monoamines.

In the present embodiment, the addition of surfactants that are conventionally known to have an effect of improving polymerization activity is not limited at all. Such surfactants include, for example, trioctylmethylammonium chloride known under the trade names of Aliquat 336 and Capriquat. The amount used is preferably within a range not exceeding 0.1% by mass with respect to 100% by mass of the total amount of the polymerization reaction mixture.

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

The polymerization temperature is not particularly limited, but if it is too low, the reaction will not progress easily, and if it is too high, the reaction selectivity may decrease and high molecular weight components may be formed. It is in the range of 35-45°C.

In the method for producing polyphenylene ether of the present embodiment, slurry polymerization is preferably performed during polyphenylene ether polymerization. By manufacturing by slurry polymerization, volatile components in the obtained polyphenylene ether can be reduced.

[Heating process]
The method for producing polyphenylene ether of the present embodiment preferably includes a heating step of heating the polymerization liquid at 60° C. for 1 hour or longer as a post-treatment after completion of the polymerization reaction.
In the heating step, an acid such as hydrochloric acid or acetic acid, ethylenediaminetetraacetic acid (EDTA) and its salts, or nitrilotriacetic acid and its salts are added to the polymerization liquid to deactivate the catalyst.
In addition, in the heating step, by-products (dihydric phenol compounds) produced by the polymerization of polyphenylene ether can be removed using a conventionally known method. As described above, when the metal ions serving as catalysts are substantially deactivated, the dihydric phenol is removed and decolorized simply by heating the polymerization mixture. Alternatively, a method of adding a required amount of a known reducing agent can be used. Known reducing agents include hydroquinone, sodium dithionite, and the like.

[Filtration process]
The method for producing polyphenylene ether of the present embodiment preferably includes a filtration step of filtering the polymerization solution that has undergone the heating step to separate the solvent and obtaining crude polyphenylene ether (a). The filtration method is not particularly limited, and conventionally known methods can be used.

[Washing process]
The method for producing polyphenylene ether of the present embodiment includes a washing step of washing the crude polyphenylene ether (a) after filtration with methanol (b) two or more times for the purpose of removing the catalyst and the high-boiling solvent. is preferred. At this time, the mass ratio (b/a) of methanol (b) to the crude polyphenylene ether (a) to be washed is preferably 4.0 or more. In this washing step, solid-liquid separation is performed twice or more while washing the crude polyphenylene ether (a) obtained in the filtration step with methanol (b), and then the resulting wet polyphenylene ether is dried.

If necessary, before solid-liquid separation, the crude polyphenylene ether (a) obtained in the filtration step may be further diluted with a poor solvent for the purpose of enhancing washability, and the slurry may be stirred.

The device for solid-liquid separation in the washing process is not particularly limited, but centrifugal separators (vibration type, screw type, decanter type, basket type, etc.), vacuum filters (drum type filters, belt filters, rotary Vacuum filter, Young filter, Nutsche, etc.), filter press, roll press, etc. can be used.

[Drying process]
Subsequently, in the method for producing polyphenylene ether of the present embodiment, the polyphenylene ether after washing is dried. The drying process can be carried out at such high temperatures that the wet polyphenylene ether does not coalesce.

The temperature of the drying treatment in the drying step is preferably at least 60°C or higher, more preferably 80°C or higher, and most preferably 120°C or higher. Drying the wet polyphenylene ether at a temperature of 60° C. or higher can efficiently reduce the content of high-boiling volatile components in the polyphenylene ether powder.

As the wet polyphenylene ether to be subjected to the drying treatment, it is preferable to reduce the content of the high-boiling solvent and amine in the polyphenylene ether as much as possible by the washing step described above. The smaller the content of the high-boiling solvent, the more likely it is that the fusion of the polyphenylene ether that can occur at high temperatures in the dryer can be suppressed.

The amount of alcohol-based solvent remaining in the polyphenylene ether after drying is 1.0 from the viewpoint of the work environment in post-processing and from the viewpoint of preventing inhibition of the reaction in which the hydroxyl group at the end of the polyphenylene ether is substituted with another functional group. It is preferably less than 0.3 mass %, more preferably 0.1 mass % or less.

In order to obtain 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. The method is preferred from the viewpoint of manufacturing efficiency.
The drying step preferably uses a dryer with a mixing function. The mixing function includes a stirring type dryer, a tumbling type dryer, and the like. As a result, the throughput can be increased, and productivity can be maintained at a high level.

The production method of the polyphenylene ether of the present embodiment is not limited to the production method described above, and the order and number of steps of the polymerization step, the heating step, the washing step, and the drying step may be appropriately adjusted.

EXAMPLES The present embodiment will be described in further detail based on examples below, but the present embodiment is not limited to the following examples.
First, the measurement methods and evaluation criteria for each physical property and evaluation are described below.

(1) Measurement of number average molecular weight (Mn), weight average molecular weight (Mw), and content of low molecular weight components As a measurement device, a gel permeation chromatography LC-2030C Plus manufactured by Shimadzu Corporation was used, and standard polystyrene and A calibration curve was prepared with ethylbenzene, and the weight average molecular weight (Mw) and number average molecular weight (Mn) of the obtained polyphenylene ether were measured using this calibration curve.
As standard polystyrene, those having molecular weights of 6890, 3140, 1260, 578, 474, 370 and 106 were used.
As the column, two K-802L columns manufactured by Showa Denko KK were connected in series. Chloroform was used as the solvent, the solvent flow rate was 1.0 mL/min, and the column temperature was 40°C. A 1 g/L chloroform solution of polyphenylene ether was prepared and used as a measurement sample. The UV wavelength of the detector was 254 nm for standard polystyrene and 283 nm for polyphenylene ether.
Based on the above measurement data, the content of low-molecular-weight components with a polystyrene-equivalent molecular weight of less than 1,000 and the content of low-molecular-weight components with a polystyrene-equivalent molecular weight of less than 500 were determined by GPC. Calculated from the area ratio.

(2) Quantification of copper element content The amount of copper element in the polyphenylene ether powder after drying is measured by inductively coupled plasma atomic emission spectrometry (ICP-AES), and the content relative to the polyphenylene ether powder to be measured. was calculated.

(3) Measurement of Number of Terminal Hydroxyl Groups 4.0 mg of polyphenylene ether was weighed. The weighed polyphenylene ether was then dissolved in 25 mL of methylene chloride. After adding 150 μL of ethanol solution of 2% by mass tetraethylammonium hydroxide (TEAH) to 2.0 mL of the prepared solution, using a UV spectrophotometer (Hitachi: U-3310 type), absorbance at 318 nm ( Abs) was measured (using a cell for absorbance measurement with a cell length of 1 cm). Then, based on the measurement results, the pseudo-molecular weight obtained from the absorbance was determined by the following formula. In addition, the number of terminal hydroxyl groups per polyphenylene ether molecule was calculated using the number average molecular weight obtained by gel permeation chromatography described in (1) above.
Pseudo-molecular weight obtained from absorbance (g/mol) = [((ε x 5)/(25 x Abs)]
Here, ε indicates the extinction coefficient and is 4700 L/mol·cm.
Number of terminal hydroxyl groups per polyphenylene ether molecule (number/molecule) =
(Number average molecular weight determined using gel permeation chromatography) / (pseudo molecular weight obtained from absorbance)

(4) Measurement of glass transition temperature The glass transition temperature of polyphenylene ether was measured using a differential scanning calorimeter DSC (DSC-8000 manufactured by PerkinElmer). After heating from room temperature to 250° C. at a rate of 20° C./min in a nitrogen atmosphere, the temperature was lowered to 50° C. at a rate of 20° C./min, and then the glass transition temperature was measured at a rate of 20° C./min.

(5) Evaluation of Solubility in Methyl Ethyl Ketone Using the polyphenylene ether obtained in each example and comparative example, the solubility in methyl ethyl ketone was evaluated. The test method was implemented as follows.
First, 18 g of methyl ethyl ketone was placed in a round-bottomed flask and gently stirred at 25° C. using a magnetic stirrer. To this, 2.0 g of the polyphenylene ether of each example was added at once, and the state inside the flask during dissolution was observed.
Immediately after dissolution, after 2 hours, and on the 2nd, 3rd and 4th days, the solubility was determined according to the following criteria.
Judgment criteria: After gently stirring with a magnetic stirrer at 25 ° C, if the methyl ethyl ketone solution is a clear solution, "◎ (excellent)", if it is a cloudy solution, "○ (good)", insoluble matter When was precipitated, it was rated as "Δ (poor)", and when it was not completely dissolved during dissolution, it was rated as "x (poor)".
When the cloudy solution is allowed to stand for a long time, it separates into a cloudy layer and a transparent layer, but no deposits on the wall of the flask are observed during stirring. On the other hand, when the insoluble matter precipitates, particulate deposits are observed on the wall of the flask during stirring.
Also, the saturated solubility was measured by the following method. In an atmosphere of 25 ° C., the polyphenylene ether of each example was added to methyl ethyl ketone at room temperature in increments of 1% by mass, and the mixture was gently stirred using a magnetic stirrer. Insoluble matter precipitated from the methyl ethyl ketone solution. The saturated solubility was defined as a concentration 1% by mass lower than the concentration obtained.

Hereinafter, the method for producing polyphenylene ether of each example and comparative example will be described.

(Example 1)
An 8.0 liter jacketed reactor equipped with a sparger for oxygen-containing gas introduction at the bottom of the reactor, stirred turbine blades and baffles, and a reflux condenser in the vent gas line at the top of the reactor was loaded with 0.3767 g of chloride. Cupric dihydrate, 1.611 g of 35% hydrochloric acid, 14.39 g of N,N,N',N'-tetramethylpropanediamine, 4855 g of methanol, 756.0 g of 2,6-dimethylphenol (table Medium “2,6-xylenol”) was added. The composition of the solvent used was only methanol. Then, while stirring vigorously, oxygen was introduced into the reactor at a rate of 500 mL/min through a sparger, and at the same time, a heating medium was passed through the jacket so as to maintain the polymerization temperature at 40°C. The polymerization solution gradually took on the form of slurry.
240 minutes after the introduction of oxygen, the oxygen-containing gas was stopped, and 15.64 g of a 50% aqueous solution of ethylenediaminetetraacetic acid tripotassium salt (reagent manufactured by Dojindo Laboratories) was added to the polymerization mixture. Then, 16.54 g of hydroquinone (reagent manufactured by Wako Pure Chemical Industries, Ltd.) was added and reacted at 60° C. for 2 hours until the polyphenylene ether slurry became white. After completion of the reaction, it is filtered and washed three times with an amount of (b) such that the mass ratio (b/a) of methanol (b) to the polyphenylene ether (a) to be washed is 4.0, and the wet polyphenylene ether got Then, it was vacuum-dried at 120° C. for 2 hours to obtain dry polyphenylene ether. Table 1 shows the analysis results of the obtained polyphenylene ether.

(Example 2)
Example except that the catalyst used was 1.507 g cupric chloride dihydrate, 6.445 g 35% hydrochloric acid, 57.55 g N,N,N',N'-tetramethylpropanediamine. A polyphenylene ether was obtained in the same manner as in method 1. Table 1 shows the analysis results of the obtained polyphenylene ether.

(Example 3)
Polyphenylene ether was prepared in the same manner as in Example 2 except that the solvent used was 485.5 g of n-butanol and 4369 g of methanol, and the composition mass ratio of the solvent used was n-butanol: methanol = 10: 90. got Table 1 shows the analysis results of the obtained polyphenylene ether.

(Comparative example 1)
Polyphenylene ether was obtained in the same manner as in Example 2 except that the solvent used was 971 g of n-butanol and 3884 g of methanol, and the composition mass ratio of the solvent used was n-butanol:methanol = 20:80. rice field. Table 1 shows the analysis results of the obtained polyphenylene ether.

(Comparative example 2)
Polyphenylene ether was obtained in the same manner as in Example 2 except that the solvent used was 1456 g of n-butanol and 3398 g of methanol, and the composition mass ratio of the solvent used was n-butanol:methanol = 30:70. rice field. Table 1 shows the analysis results of the obtained polyphenylene ether.

(Comparative Example 3)
The solvent used was 1942 g of n-butanol and 2913 g of methanol, and the composition weight ratio of the solvent used was n-butanol:methanol = 40:60. Dojindo Laboratories reagent) was dissolved in a 50% aqueous solution, then 16.54 g of hydroquinone (Wako Pure Chemical reagent) was added, and the slurry was heated at 50 ° C. until the polyphenylene ether became white. After reacting for 1 hour, filtering after completion of the reaction, the mass ratio (b/a) of methanol (b) to the polyphenylene ether (a) to be washed is 3.0. A polyphenylene ether was obtained in the same manner as in Example 2, except that it was washed twice. Table 1 shows the analysis results of the obtained polyphenylene ether.

(Comparative Example 4)
Polyphenylene ether was obtained in the same manner as in Example 2 except that the solvent used was only 4855 g of n-butanol and the composition mass ratio of the solvent used was n-butanol:methanol = 100:0. Table 1 shows the analysis results of the obtained polyphenylene ether.

(Comparative Example 5)
A 50% aqueous solution of 15.64 g of ethylenediaminetetraacetic acid tripotassium salt (reagent manufactured by Dojindo Laboratories) was added to the polymerization mixture, and then 16.54 g of hydroquinone (reagent manufactured by Wako Pure Chemical Industries, Ltd.) was added, The slurry polyphenylene ether was reacted at 40° C. for 2 hours until it became white, filtered after the reaction was completed, and the mass ratio of methanol (b) to the polyphenylene ether (a) to be washed (b/a A polyphenylene ether was obtained in the same manner as in Example 2, except that it was washed 6 times with an amount of (b) such that ) was 4.0. Table 1 shows the analysis results of the obtained polyphenylene ether.

(Comparative Example 6)
0.89 L/min. While blowing nitrogen gas at a flow rate, 0.0745 g of cupric oxide, 0.560 g of 47% by mass aqueous hydrogen bromide solution, 0.179 g of di-t-butylethylenediamine, 0.869 g of di-n-butylamine, 2.643 g of butyldimethylamine, 515 g of toluene and 57.8 g of 2,6-dimethylphenol were added and stirred until a uniform solution was obtained and the internal temperature of the polymerization tank reached 40°C.
Next, dry air was introduced into the polymerization tank from a sparger at a rate of 0.61 NL/min to initiate polymerization and allow the polymerization reaction to proceed. After aeration of dry air for 120 minutes, the aeration was stopped to terminate the polymerization reaction and obtain a polymerization mixture. The internal temperature of the polymerization vessel was controlled to 40° C. at the end of the polymerization. At the end of the polymerization, the polymerization liquid was in a solution state.
60 g of a 10% by mass aqueous solution of ethylenediaminetetraacetic acid tetrasodium salt (reagent manufactured by Dojindo Laboratories) was added to the resulting polymerization mixture. After stirring the polymerization mixture at 70° C. for 2 hours, the mixture was allowed to stand for 30 minutes to separate, and the aqueous solution on the water layer side was discharged.
Next, 60 g of pure water (first time) was added to the polymerization reaction solution (oil layer side), stirred for 20 minutes, separated by standing for 30 minutes, and the water layer side was discharged. Then, 60 g of pure water (second time) was added to the polymerization reaction solution (on the oil layer side), stirred for 20 minutes, separated by standing for 30 minutes, and the water layer side was discharged.
The polymerization reaction solution (on the oil layer side) was returned to room temperature, and an excess amount of methanol was added to obtain a slurry solution in which a polyphenylene ether resin was precipitated. Thereafter, the slurry liquid was filtered through a glass filter to obtain wet polyphenylene ether. Excess methanol was added to the wet polyphenylene ether and filtered again to obtain wet polyphenylene ether. The resulting wet polyphenylene ether was held at 150° C. and 1 mmHg for 2 hours to obtain a dry polyphenylene ether resin. Table 1 shows the analysis results of the obtained polyphenylene ether.

The polyphenylene ether of the present invention has a small amount of high-molecular components and a high content of low-molecular-weight components, and thus has excellent solvent solubility. In addition, it is excellent in dissolution stability, and has good storage stability and fluidity when prepared as a varnish or the like, so it is industrially useful as a modifier or the like.

Claims (9)

A polyphenylene ether having a structural unit derived from a phenolic compound represented by the following general formula (1), having a weight average molecular weight (Mw) of less than 2500, and a ratio of the weight average molecular weight to the number average molecular weight (Mn) (Mw /Mn) is 1.2 to 1.6, the content of components having a molecular weight of less than 1000 is 10 mass% or more, and the content of the copper compound is less than 100 mass ppm as copper element. , polyphenylene ether.

(Wherein, R1, R2, and R3 each represent an independent substituent, and R1 is an alkyl group, substituted alkyl group, aralkyl group, substituted aralkyl group, aryl group, substituted aryl group, alkoxy group, or substituted alkoxy group. , R2, and R3 may be the same groups as those defined for R1, and may also be a hydrogen atom or a halogen atom.) 2. The polyphenylene ether according to claim 1, wherein the content of components having a molecular weight of less than 500 is 4.0% by mass or more. The polyphenylene ether according to claim 1 or 2, wherein the content of the copper compound is 60 mass ppm or less as copper element The polyphenylene ether according to any one of claims 1 to 3, which has a saturated solubility of 40% by mass or more in an atmosphere of 25°C in methyl ethyl ketone. A process for polyphenylene ethers according to any one of claims 1 to 4, wherein a phenolic compound is polymerized in the presence of a polymerization catalyst and oxygen in a polymerization solvent, wherein 90 to 100% by weight of the polymerization solvent is A heating step of heating a polymerization liquid that is methanol and contains the polymerization solvent and the phenol compound at 60 ° C. for 1 hour or more, and a filtration step of filtering the polymerization liquid after heating to obtain a crude polyphenylene ether (a); and a washing step of washing the crude polyphenylene ether (a) with methanol (b) two or more times, wherein the mass ratio (b/a) of the methanol (b) to the crude polyphenylene ether (a) in the washing step is 4.0 or more. An adhesive composition comprising the polyphenylene ether according to any one of claims 1 to 4 and a thermosetting resin. 7. The adhesive composition of claim 6, wherein said thermosetting resin is an epoxy resin. 8. The adhesive composition according to claim 6 or 7, further comprising a curing accelerator. The adhesive composition according to any one of claims 6 to 8, further comprising a solvent.