Polyphenylene ether, method of manufacturing the same, thermosetting composition, prepreg and laminate

Abstract

The present invention aims to provide a polyphenylene ether having excellent solubility in general-purpose ketone-based solvents and a method for manufacturing the same. Furthermore, the invention aims to provide a thermosetting composition, prepreg, and laminate using the said polyphenylene ether. The polyphenylene ether of the present invention is characterized by comprising 5 to 85 mol% of repeating units derived from the phenol of Formula (1) and 15 to 95 mol% of repeating units derived from the phenol of Formula (2) with respect to 100 mol% of the total of repeating units derived from the phenol of Formula (1) and repeating units derived from the phenol of Formula (2), and having a reduction viscosity (ηsp / c) of 0.03 to 0.30 dL / g measured in a chloroform solution with a concentration of 0.5 g / dL at 30°C.

Description

Technology Field

[0001] The present invention relates to polyphenylene ether, a method for manufacturing the same, a thermosetting composition, prepreg, and a laminate. Background Technology

[0002] Polyphenylene ether (hereinafter also referred to as “PPE”) is widely used as a material for products and parts in the electrical and electronic, automotive, and food and packaging fields, as well as in various other industrial materials fields, because it possesses excellent high-frequency characteristics, flame retardancy, and heat resistance. In particular, in recent years, taking advantage of its low dielectric properties and heat resistance, it has been applied as a modifier for electronic materials such as substrate materials and for various other applications.

[0003] However, high molecular weight polyphenylene ethers having repeating units derived from monovalent phenols, generally represented by 2,6-dimethylphenol, are soluble in highly toxic solvents such as chloroform, but have the problem of being difficult to dissolve at high concentrations at room temperature in aromatic solvents such as toluene, which are known as dual solvents, and also being insoluble in ketone solvents such as methyl ethyl ketone. Therefore, when used, for example, as a wiring board material, it becomes difficult to handle resin varnish solutions such as toluene or methyl ethyl ketone.

[0004] Patent Document 1 discloses that a polyphenylene ether having a low molecular weight and a specific particle size has excellent solubility in solvents such as methyl ethyl ketone.

[0005] In addition, Patent Document 2 describes a modified polyphenylene ether compound having a predetermined polyphenylene ether portion in its molecular structure and having at least one p-ethenylbenzyl group or m-ethenylbenzyl group, etc., at the end of the molecule.

[0006] In addition, Patent Document 3 describes a modified polymer having a polyphenylene ether portion in its molecular structure and a methacrylic group at the end of the molecule. Prior art literature

[0007] Japanese Patent Publication No. 2004-99824 Japanese Patent Publication No. 2004-339328 Japanese Patent Publication No. 2008-510059 The problem to be solved

[0008] As described above, Patent Documents 1 to 3 disclose methods for manufacturing low-molecular-weight polyphenylene ethers, etc., to improve the solvent solubility of polyphenylene ethers; however, simply lowering the molecular weight of polyphenylene ethers is not sufficient as it does not significantly improve solubility at room temperature in general-purpose ketone-based solvents such as methyl ethyl ketone. In particular, a method to improve long-term solvent solubility in ketone-based solvents is desired.

[0009] The present invention has been made in consideration of the above-mentioned problem and aims to provide a polyphenylene ether having excellent solubility in general-purpose ketone-based solvents and a method for manufacturing the same. Furthermore, it aims to provide a thermosetting composition, prepreg, and laminate using the said polyphenylene ether. means of solving the problem

[0010] That is, the present invention is as follows.

[0011] [1]

[0012] With respect to the total of 100 mol% of the repeating unit derived from phenol of the following formula (1) and the repeating unit derived from phenol of the following formula (2), it comprises 5 to 85 mol% of the repeating unit derived from phenol of the following formula (1) and 15 to 95 mol% of the repeating unit derived from phenol of the following formula (2),

[0013] Polyphenylene ether characterized by a reducing viscosity (ηsp / c) of 0.03 to 0.30 dL / g measured in a chloroform solution at a concentration of 0.5 g / dL at 30℃.

[0014]

[0015] (In Equation (1), R 11 Each is independently a saturated hydrocarbon group having 1 to 6 carbon atoms that may be substituted, an aryl group having 6 to 12 carbon atoms that may be substituted, or a halogen atom, and R 12 Each is independently a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms that may be substituted, an aryl group having 6 to 12 carbon atoms that may be substituted, or a halogen atom.

[0016]

[0017] (In Equation (2), R 22 Each is independently a hydrogen atom, a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms that may be substituted, an aryl group having 6 to 12 carbon atoms that may be substituted, or a halogen atom, and two Rs 22 Both sides are not hydrogen atoms, and R 21 is a substructure represented by the following equation (3).

[0018]

[0019] (Equation (3), R 31 Each is independently a straight-chain alkyl group having 1 to 8 carbon atoms that may be substituted, or two Rs 31 It is a cyclic alkyl structure having 1 to 8 carbon atoms bonded together, and R 32 is each independently an alkylene group having 1 to 8 carbon atoms that may be substituted, b is each independently 0 or 1, and R 33 It is silver, a hydrogen atom, a carbon-1 to carbon-8 alkyl group that may be substituted, or a phenyl group that may be substituted.

[0020] [2]

[0021] Polyphenylene ether described in [1], wherein the partial structure represented by the above formula (3) is a t-butyl group.

[0022] [3]

[0023] Polyphenylene ethers described in [1] or [2], having an average number of hydroxyl groups of less than 2.5 / molecule.

[0024] [4]

[0025] Polyphenylene ether described in any of [1] to [3], having an average number of hydroxyl groups of less than 0.2 / molecule.

[0026] [5]

[0027] A polyphenylene ether described in any one of [1] to [4] having at least one substructure selected from the group consisting of the following formulas (4), (5), (6) and (7), and having an average number of hydroxyl groups less than 0.2 / molecule.

[0028]

[0029]

[0030]

[0031] (In Equation (6), R 6 It is silver, a hydrogen atom, or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and the saturated or unsaturated hydrocarbon may have substituents to the extent that it satisfies the condition of having 1 to 10 carbon atoms.

[0032]

[0033] (Equation (7), R 7 Silver is a saturated or unsaturated divalent hydrocarbon group having 1 to 10 carbon atoms, and said saturated or unsaturated divalent hydrocarbon may have substituents to the extent that it satisfies the condition of having 1 to 10 carbon atoms, and R 8 It is a hydrogen atom or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and said saturated or unsaturated hydrocarbon may have substituents to the extent that it satisfies the condition of having 1 to 10 carbon atoms.)

[0034] [6]

[0035] A polyphenylene ether described in any one of [1] to [5] comprising a repeating unit derived from a monovalent phenol having at least one unsaturated hydrocarbon group at the carbon atom at the ortho position of the carbon atom to which the hydroxyl group of the phenol is bonded.

[0036] [7]

[0037] The polyphenylene ether described in [6], wherein the monovalent phenol is 2-allylphenol or 2-methyl-6-allylphenol.

[0038] [8]

[0039] A method for producing polyphenylene ether as described in any one of [1] to [7], comprising a process of performing oxidative polymerization of the phenol of formula (1) and the phenol of formula (2).

[0040] [9]

[0041] A polyphenylene ether solution comprising a polyphenylene ether described in any one of [1] to [7] and a ketone-based solvent.

[0042]

[10]

[0043] A thermosetting composition comprising polyphenylene ether as described in any one of [1] to [7].

[0044]

[11]

[0045] A prepreg comprising the thermosetting composition described in

[10] .

[0046]

[12]

[0047] The prepreg described in

[11] , which is glass cloth.

[0048]

[13]

[0049] A laminate characterized by comprising a cured prepreg as described in

[11] or

[12] and a metal foil. Effects of the invention

[0050] According to the present invention, a polyphenylene ether having excellent solubility in general-purpose ketone-based solvents and a method for manufacturing the same can be provided. In addition, a thermosetting composition, prepreg, and laminate using the said polyphenylene ether can be provided. Specific details for implementing the invention

[0051] Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as "present embodiments") will be described in detail. The present embodiments below are examples for explaining the present invention, and the present invention is not limited to these present embodiments; rather, the present invention may be implemented with appropriate modifications within the scope of its gist.

[0052] In the present embodiment, a polyphenylene ether in which some or all of the hydroxyl groups contained therein have been modified may be simply referred to as "polyphenylene ether." Accordingly, where expressed as "polyphenylene ether," it includes both unmodified polyphenylene ether and modified polyphenylene ether, unless a particular contradiction arises.

[0053] In addition, in this specification, A (numerical value) to B (numerical value) means A or more and B or less. In addition, in this specification, substituents may include, for example, saturated or unsaturated hydrocarbon groups having 1 to 10 carbon atoms, aryl groups having 6 to 10 carbon atoms, and halogen atoms.

[0054] Polyphenylene ether

[0055] The polyphenylene ether of the present embodiment comprises at least a repeating unit derived from phenol of the following formula (1) and a repeating unit derived from phenol of the following formula (2), and the repeating unit in the compound may consist only of a repeating unit derived from phenol of the following formula (1) and a repeating unit derived from phenol of the following formula (2).

[0056]

[0057] (In Equation (1), R 11 Each is independently a saturated hydrocarbon group having 1 to 6 carbon atoms that may be substituted, an aryl group having 6 to 12 carbon atoms that may be substituted, or a halogen atom, and R 12 Each is independently a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms that may be substituted, an aryl group having 6 to 12 carbon atoms that may be substituted, or a halogen atom.

[0058]

[0059] (In Equation (2), R 22 Each is independently a hydrogen atom, a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms that may be substituted, an aryl group having 6 to 12 carbon atoms that may be substituted, or a halogen atom, and two Rs 22 Both sides are not hydrogen atoms, and R 21 is a substructure represented by the following equation (3).

[0060]

[0061] (Equation (3), R 31 Each is independently a straight-chain alkyl group having 1 to 8 carbon atoms that may be substituted, or two Rs 31 It is a cyclic alkyl structure having 1 to 8 carbon atoms bonded together, and R 32 is each independently an alkylene group having 1 to 8 carbon atoms that may be substituted, b is each independently 0 or 1, and R 33 It is any one of silver, a hydrogen atom, a carbon-1 to carbon-8 alkyl group that may be substituted, or a phenyl group that may be substituted.

[0062] In the above equation (1), R 11Each is preferably independently a saturated hydrocarbon group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, more preferably a methyl group or a phenyl group, and even more preferably a methyl group. In Formula (1), the two Rs 11 It is desirable that all have the same structure.

[0063] The above R 11 Examples of substituents for the saturated hydrocarbon group having 1 to 6 carbon atoms and the aryl group having 6 to 12 carbon atoms include a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a halogen atom.

[0064] In the above equation (1), R 12 Each is preferably independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and more preferably a hydrogen atom or a methyl group. In Formula (1), the two Rs 12 It is preferable that it be different, and more preferable that one side is a hydrogen atom and the other side is a hydrocarbon group having 1 to 6 carbon atoms (preferably a methyl group).

[0065] The above R 12 Examples of substituents for the hydrocarbon group having 1 to 6 carbon atoms and the aryl group having 6 to 12 carbon atoms include a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a halogen atom.

[0066] In the above equation (2), R 22 Preferably, each is an aryl group having 6 to 12 carbon atoms that may be independently substituted with a hydrogen atom, a saturated or unsaturated hydrocarbon group having 1 to 15 carbon atoms, or an alkyl group having 1 to 6 carbon atoms; more preferably, it is an aryl group having 6 to 10 carbon atoms that may be substituted with a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms; and even more preferably, it is a hydrogen atom or a methyl group. In Formula (2), two Rs 22It is preferable that it be different, and more preferable that one side is a hydrogen atom and the other side is a hydrocarbon group having 1 to 6 carbon atoms (preferably a methyl group).

[0067] The above R 22 Examples of substituents for a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms and an aryl group having 6 to 12 carbon atoms include a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a halogen atom.

[0068] The partial structure represented by the above formula (3) is preferably a group containing secondary and / or tertiary carbons, such as an isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, tert-amyl group, 2,2-dimethylpropyl group, cyclohexyl group, or a structure having a phenyl group at the end thereof, more preferably a tert-butyl group or a cyclohexyl group, and even more preferably a tert-butyl group.

[0069] In addition, the above R 31 A substituent in a straight-chain alkyl group having 1 to 8 carbon atoms, said R 32 A substituent in an alkylene group having 1 to 8 carbon atoms and R 33 Examples of substituents for the alkyl group having 1 to 8 carbon atoms and the phenyl group include a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a halogen atom.

[0070] In the present embodiment, the structure of polyphenylene ether can be identified by analyzing it using methods such as NMR and mass spectrometry. As a specific method for identifying the structure of polyphenylene ether, it is possible to estimate repeating units by performing field-departing mass spectrometry (FD-MS), which is known to be resistant to fragmentation, and the spacing of the detected ions. Additionally, a method for estimating the structure of polyphenylene ether can be provided by combining the analysis of fragment ion peaks using electron ionization (EI) with structural analysis by NMR.

[0071] The polyphenylene ether of the present embodiment contains 5 to 85 mol% of repeating units derived from the phenol of Formula (1) and 15 to 95 mol% of repeating units derived from the phenol of Formula (2), based on a total of 100 mol% of repeating units derived from the phenol of Formula (1) and repeating units derived from the phenol of Formula (2). In the view of obtaining a polyphenylene ether with excellent solvent solubility and low dielectric loss tangent, it is preferable that the repeating units derived from the phenol of Formula (2) be 18 mol% or more, and more preferably 20 mol% or more. In the same view, it is preferable that the repeating units derived from the phenol of Formula (1) be 82 mol% or less, and more preferably 80 mol% or less.

[0072] The repeating unit derived from the phenol of Formula (1) included in the polyphenylene ether of the present embodiment may be one or multiple types. Additionally, the repeating unit derived from the phenol of Formula (2) included in the polyphenylene ether of the present embodiment may be one or multiple types.

[0073] For 100 mol% of monomer units (e.g., total monomer units derived from phenol included in the polyphenylene ether) of the present embodiment, the total molar of repeating units derived from phenol of Formula (1) and repeating units derived from phenol of Formula (2) is preferably 75 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more.

[0074] The respective ratios of the repeating unit derived from the phenol of Formula (1) and the repeating unit derived from the phenol of Formula (2) are, for example, 1 H NMR, 13 It can be obtained using interpretation methods such as C NMR, and more specifically, it can be measured by the method described in the examples below.

[0075] Since the phenol of formula (1) does not have unsubstituted ortho positions (i.e., hydrogen atoms are not 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 other phenolic monomers only at the carbon atoms at the para positions of the phenolic hydroxyl group. Therefore, the repeating unit derived from formula (1) includes a repeating unit having the structure of formula (8) below.

[0076]

[0077] (Equation (8), R 11 and R 12 is the same as Equation (1).

[0078] The phenol of formula (2) can react with other phenolic monomers at either the ortho or para position of the phenol in addition to the phenolic hydroxyl group. Thus, the repeating unit derived from the phenol of formula (2) has the monomer unit of formula (9) below, formula (10) below, or a combination thereof.

[0079]

[0080]

[0081] (R in Equation (9) and Equation (10)) 21 , R 22 is the same as Equation (2).

[0082] In this embodiment, the reducing viscosity of the polyphenylene ether measured in a chloroform solution at a concentration of 0.5 g / dL at 30°C is preferably 0.03 to 0.30 dL / g, and more preferably 0.06 to 0.30 dL / g.

[0083] The reduction viscosity can be appropriately selected depending on the application. For example, if it is desired to further improve fluidity when dissolved in the solvent used to produce the varnish during the application process to substrate materials, a low reduction viscosity is desirable.

[0084] The reduction viscosity can be measured by the method described in the examples below.

[0085] In the present embodiment, the polyphenylene ether may contain, in addition to the phenol of formula (1) and the phenol of formula (2), a ternary copolymer containing a structure derived from the divalent phenol of formula (11) as an impurity (in this specification, it may simply be referred to as "impurity A"). The polyphenylene ether of the present embodiment may be a mixture of the polyphenylene ether and the impurity A. The molar ratio of impurity A to 100 mol% of the polyphenylene ether of the embodiment is preferably 10 mol% or less, and more preferably 5 mol% or less.

[0086] The above impurity A can be synthesized as a ternary copolymer containing a structure derived from divalent phenol with z=0 of formula (11) by reacting the following formula (12), which is generated as a byproduct during the oxidative polymerization of monovalent phenol, with a polyphenylene ether composed of monovalent phenol.

[0087]

[0088] (In Equation (11), R 11 and R 12 is the same as Equation (1). z is 0 or 1, and Y is,

[0089]

[0090] (during food, R 41 Each is independently any one of a hydrocarbon group having 1 to 6 carbon atoms that may be substituted, an aryl group having 6 to 12 carbon atoms that may be substituted, and a halogen atom.

[0091]

[0092] (In Equation (12), R 11 and R 12 is the same as Equation (1).

[0093] In the present embodiment, the average number of hydroxyl groups of the polyphenylene ether is preferably less than 2.5 / molecule for the unmodified polyphenylene ether, more preferably less than 2.2 / molecule, and even more preferably less than 2.0 / molecule. If the average number of hydroxyl groups exceeds 2.5 / molecule, it means that the polyphenylene ether is a multi-branched type unmodified polyphenylene ether that has not undergone structural control.

[0094] The average hydroxyl number can be measured by the method described in the following examples.

[0095] The polyphenylene ether in the present embodiment may be a modified polyphenylene ether in which the hydroxyl groups included in the polyphenylene ether are modified into functional groups (e.g., functional groups including unsaturated carbon bonds). In the case of the modified polyphenylene ether, it is preferable that the average number of hydroxyl groups is less than 0.2 / molecule, more preferable that it is less than 0.1 / molecule, and even more preferable that it is less than 0.01 / molecule.

[0096] The polyphenylene ether in this embodiment may have at least one partial structure selected from the group consisting of the following formulas (4), (5), (6) and (7).

[0097]

[0098]

[0099]

[0100] (In Equation (6), R 6 It is silver, a hydrogen atom, or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and the saturated or unsaturated hydrocarbon is R 6 It may have substituents within the range where the total number of carbon atoms is 1 to 10.

[0101]

[0102] (Equation (7), R 7 Silver is a saturated or unsaturated divalent hydrocarbon group having 1 to 10 carbon atoms, and the saturated or unsaturated divalent hydrocarbon is R 7 It may have substituents within the range where the total number of carbon atoms is 1 to 10, and R 8 It is silver, a hydrogen atom, or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and the said saturated or unsaturated hydrocarbon is R 8 It may have substituents within the range where the total number of carbon atoms is 1 to 10.

[0103] In addition, a partial structure represented by at least one selected from the group consisting of the above formulas (4), (5), (6), and (7) may be directly bonded to a hydroxyl group contained in the polyphenylene ether.

[0104] The respective ratios of the repeating unit derived from the phenol of Formula (1) and the repeating unit derived from the phenol of Formula (2) included in the modified polyphenylene ether having a partial structure represented by at least one selected from the group consisting of Formulas (4), (5), (6), and (7) are, for example, 1 H NMR, 13 It can be obtained using interpretation methods such as C NMR, and more specifically, it can be measured by the method described in the examples below.

[0105] The polyphenylene ether in the present embodiment may include a monovalent phenol having at least one unsaturated hydrocarbon group at the ortho-position carbon atom of the carbon atom to which the hydroxyl group of the phenol is bonded. Preferably, the monovalent phenol has only one unsaturated hydrocarbon group bonded to the ortho-position carbon atom of the carbon atom to which the hydroxyl group of the phenol is bonded. The unsaturated hydrocarbon may be bonded to one carbon atom at each ortho-position carbon atom of the carbon atom to which the hydroxyl group of the monovalent phenol is bonded, or may be bonded to one carbon atom at the ortho-position carbon atom of the carbon atom to which the hydroxyl group of the phenol is bonded. Furthermore, the monovalent phenol having at least one unsaturated hydrocarbon group at the ortho-position carbon atom of the carbon atom to which the hydroxyl group of the phenol is bonded refers to a monovalent phenol different from the phenol of Formula (1) or the phenol of Formula (2).

[0106] As for the unsaturated hydrocarbon group, it is preferable to have an unsaturated hydrocarbon group having 3 to 10 carbon atoms, and it is preferable to have an unsaturated hydrocarbon group having 3 to 5 carbon atoms. Examples of such unsaturated hydrocarbon groups include alkenyl groups (e.g., vinyl groups, allyl groups, etc.) and alkynyl groups (e.g., ethinyl groups, 1-propynyl, 2-propynyl, etc.).

[0107] The above unsaturated hydrocarbon may have substituents to the extent that it satisfies the condition of having 3 to 10 carbon atoms.

[0108] The introduction rate of monovalent phenol having at least one unsaturated hydrocarbon group at the ortho position of the carbon atom to which the hydroxyl group of phenol is bonded may be appropriately adjusted to control the number of curable functional groups, but with respect to the total of the phenol of Formula (1) and the monovalent phenol having at least one unsaturated hydrocarbon group at the ortho position of the carbon atom to which the hydroxyl group of phenol is bonded, the monovalent phenol having at least one unsaturated hydrocarbon group at the ortho position of the carbon atom to which the hydroxyl group of phenol is bonded is preferably 0.1 to 30 mol%, and more preferably 0.1 to 25 mol%.

[0109] In the polyphenylene ether of the present embodiment, the molar ratio of the repeating unit derived from the monovalent phenol having at least one unsaturated hydrocarbon group at the ortho position of the carbon atom to which the hydroxyl group of the phenol is bonded, to the sum of the repeating unit derived from the phenol of Formula (1) and the repeating unit derived from the monovalent phenol having at least one unsaturated hydrocarbon group at the ortho position of the carbon atom to which the hydroxyl group of the phenol is bonded, is preferably 0.1 to 40 mol%, and more preferably 0.1 to 10 mol%.

[0110] Method for manufacturing polyphenylene ether

[0111] The polyphenylene ether of the present embodiment is obtained by a method comprising at least a process of oxidative polymerization of a monovalent phenol compound represented by, for example, formulas (1) and (2). The process of oxidative polymerization preferably involves oxidative polymerization of a raw material comprising at least the phenol of formula (1) and the phenol of formula (2).

[0112] As a monovalent phenol compound represented by the above formula (1), for example, 2,6-dimethylphenol, 2-methyl-6-ethylphenol, 2,6-diethylphenol, 2-ethyl-6-n-propylphenol, 2-methyl-6-chlorphenol, 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-chlorphenol, 2-methyl-6-phenylphenol, 2,6-diphenylphenol, 2-methyl-6-tolylphenol, 2,6-ditrilphenol, 2,3,6-trimethylphenol, 2,3-diethyl-6-n-propylphenol, 2,3,6-tributylphenol, 2,6-di-n-butyl-3-methylphenol, Examples include 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 preferred because they are particularly inexpensive and easy to obtain.

[0113] The monovalent phenol compound represented by the above formula (1) may be used as a single type or in combination of multiple types.

[0114] Examples of monovalent phenol compounds 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 perspective of inhibiting multi-branching and inhibiting gelation, 2-t-butyl-5-methylphenol and 2-cyclohexyl-5-methylphenol, which are bulky substituents, are more preferred.

[0115] The monovalent phenol compound represented by the above formula (2) may be used as a single type or in combination of multiple types.

[0116] The process of performing the above oxidative polymerization may be, for example, a process of performing oxidative polymerization of a raw material comprising, in addition to the phenol of formula (1) and the phenol of formula (2), a monovalent phenol having at least one unsaturated hydrocarbon group at the ortho position of the carbon atom to which the hydroxyl group of the phenol is bonded.

[0117] As a monovalent phenol having at least one unsaturated hydrocarbon group at the ortho-position carbon atom of the carbon atom to which the hydroxyl group of the phenol is bonded, it is preferred to be a monovalent phenol in which at least one (preferably one) unsaturated hydrocarbon group is bonded to the ortho-position carbon atom and hydrogen atoms are bonded to the meta-position and para-position carbon atoms, more preferably 2-allylphenol, 2-allyl-6-methylphenol, and even more preferably 2-allylphenol.

[0118] The monovalent phenol having at least one unsaturated hydrocarbon group at the carbon atom at the ortho position of the carbon atom to which the hydroxyl group of the phenol is bonded may be used as a single type or may be used in combination of multiple types.

[0119] Typically, in the oxidative polymerization of phenols having hydrogen atoms in the ortho position (e.g., 2-methylphenol, 2,5-dimethylphenol, 2-phenylphenol), since ether bonds can be formed even in the ortho position, it becomes difficult to control the bonding positions of the phenol compounds during oxidative polymerization, and a high molecular weight polymer is obtained in a branched form with an average number of hydroxyl groups of 3 or more per molecule, and finally, a gel component insoluble in solvent is generated (refer to the oxidative polymerization of 2,5-dimethylphenol and 2,6-dimethylphenol in Reference Example 1 below).

[0120] Meanwhile, when a phenol having a bulky substituent at the ortho position on one side, as indicated by the above formula (2), is used, the bonding position of the phenol compound during oxidative polymerization can be controlled even though it has a hydrogen atom at the ortho position on the opposite side, so that a polyphenylene ether with an average hydroxyl group of less than 2.5 / molecule can be obtained.

[0121] Furthermore, when using a phenol having a bulky substituent at the ortho position of one side represented by the above formula (2), even when using a monovalent phenol having a bulky substituent (e.g., hydrogen atom, allyl group, methyl group, ethyl group, methoxy group, etc.) at the ortho position of the oxygen atom of the phenol as the third component, it is possible to obtain a polyphenylene ether with an average of less than 2.5 hydroxyl groups / molecule without gelling.

[0122] In the present embodiment, the molecular weight of the polyphenylene ether can be adjusted by the molar ratio of the repeating unit derived from Equation (2) to the sum of the repeating unit derived from Equation (1) and the repeating unit derived from Equation (2). That is, when the molar ratio of the repeating unit derived from Equation (2) is high, the molecular weight (reduction viscosity) can be lowered, and when the molar ratio of the repeating unit derived from Equation (2) is low, the molecular weight (reduction viscosity) can be adjusted to be high. Although the reason for this is not obvious, it is presumed that high molecular weight is suppressed by the bulky substitution of the ortho position of Equation (2).

[0123] (Oxidative Polymerization Process)

[0124] Here, in the method for manufacturing polyphenylene ether, an aromatic solvent that is a solvent for polyphenylene ether can be used as a polymerization solvent in the oxidative polymerization process.

[0125] Here, a solvent for polyphenylene ether is a solvent capable of dissolving polyphenylene ether, and examples of such solvents include aromatic hydrocarbons such as benzene, toluene, xylene (including each isomer of o-, m-, and p-), and ethylbenzene, halogenated hydrocarbons such as chlorobenzene and dichlorobenzene; and nitro compounds such as nitrobenzene.

[0126] As the polymerization catalyst used in the present embodiment, a known catalyst system that is generally applicable to the production of polyphenylene ether may be used. Generally known catalyst systems are known to consist of a transition metal ion having redox ability and an amine compound capable of forming a complex with said transition metal ion, such as a catalyst system consisting of a copper compound and an amine compound, a catalyst system consisting of a manganese compound and an amine compound, or a catalyst system consisting of a cobalt compound and an amine compound. Since the polymerization reaction proceeds efficiently under slightly alkaline conditions, a small amount of alkali or an additional amine compound may be added thereto.

[0127] The polymerization catalyst suitably used in this embodiment is a catalyst composed of a copper compound, a halogen compound, and an amine compound as components of the catalyst, and more preferably, a catalyst comprising a diamine compound represented by the following formula (13) as the amine compound.

[0128]

[0129] In Equation (13), R 14 , R 15 , R 16 , R 17 Each is independently a hydrogen atom, a straight-chain or branched alkyl group having 1 to 6 carbon atoms, and not all of them are simultaneously hydrogen atoms. 18 It is an alkylene group having a straight chain or methyl branch with 2 to 5 carbon atoms.

[0130] Examples of copper compounds of the catalytic components described herein are listed. Suitable copper compounds may include a first copper compound, a second copper compound, or a mixture thereof. Examples of second copper compounds include copper(II) chloride, copper(II) bromide, copper(II) sulfate, copper(II) nitrate, etc. Additionally, examples of first copper compounds include copper(II) chloride, copper(II) bromide, copper(II) sulfate, copper(II) nitrate, etc. Among these, particularly preferred metal compounds are copper(II) chloride, copper(II) chloride, copper(II) bromide, and copper(II) bromide. Furthermore, these copper salts may be synthesized at use from halogens or acids corresponding to oxides (e.g., copper(II) oxide), carbonates, hydroxides, etc. A frequently used method is to prepare them by mixing the copper(II) oxide exemplified above with a hydrogen halide (or a solution of a hydrogen halide).

[0131] Examples of 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, tetraethylammonium iodide, etc. In addition, these can be used as aqueous solutions or as solutions using a suitable solvent. These halogen compounds may be used as components alone or in combination of two or more types. Preferred halogen compounds are aqueous solutions of hydrogen chloride and aqueous solutions of hydrogen bromide.

[0132] The amount of these compounds used is not particularly limited, but preferably 2 to 20 times the molar amount of copper atoms as halogen atoms, and the amount of copper atoms preferred per 100 moles of phenol compound added to the polymerization reaction is in the range of 0.02 moles to 0.6 moles.

[0133] Next, examples of diamine compounds as catalytic components are listed. For example, 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, Examples include 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, etc. In the present embodiment, the preferred diamine compound is one in which the alkylene group connecting two nitrogen atoms has 2 or 3 carbon atoms. The amount of these diamine compounds used is not particularly limited, but is preferably in the range of 0.01 mole to 10 mole per 100 moles of phenol compound added to the polymerization reaction.

[0134] In this embodiment, primary amines and secondary monoamines may be included as 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, etc.

[0135] As a component of the polymerization catalyst in the present embodiment, a tertiary monoamine compound may be included. A tertiary monoamine compound is an aliphatic tertiary amine including an alicyclic tertiary amine. Examples include trimethylamine, triethylamine, tripropylamine, tributylamine, triisobutylamine, dimethylethylamine, dimethylpropylamine, allyldiethylamine, dimethyl-n-butylamine, diethylisopropylamine, N-methylcyclohexylamine, etc. These tertiary monoamines may be used alone or in combination of two or more types. The amount used is not particularly limited, but a range of 15 moles or less per 100 moles of phenol compound added to the polymerization reaction is preferred.

[0136] In this embodiment, there are no restrictions on adding a surfactant known to have an effect of improving polymerization activity compared to conventional surfactants. Examples of such surfactants include trioctylmethylammonium chloride, known by the trade names Aliquat 336 or Capriquat. The amount used is preferably in a range not exceeding 0.1 mass% relative to 100 mass% of the total amount of the polymerization reaction mixture.

[0137] As the oxygen-containing gas in the polymerization of the present embodiment, 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 may be used. While atmospheric pressure is sufficient for the system pressure during the polymerization reaction, it may be used at reduced pressure or increased pressure as needed.

[0138] The temperature of the polymerization is not particularly limited, but if it is too low, the reaction is difficult to proceed, and if it is too high, there is a risk of reduced reaction selectivity or the formation of a gel, so it is in the range of 0 to 60°C, preferably 10 to 40°C.

[0139] In the method for manufacturing polyphenylene ether, polymerization may be carried out in a solvent such as alcohol.

[0140] (Copper extraction and byproduct removal process)

[0141] In the present embodiment, there are no particular limitations on the post-treatment method after the polymerization reaction is completed. Typically, an acid such as hydrochloric acid or acetic acid, or ethylenediaminetetraacetic acid (EDTA) and its salt, nitrilotriacetic acid and its salt, etc., is added to the reaction solution to deactivate the catalyst. In addition, the method of removing by-products of divalent phenols generated by the polymerization of polyphenylene ether can also be carried out using conventional known methods. As described above, if the metal ions acting as catalyst are substantially deactivated, the mixture is decolorized simply by heating. Alternatively, it is also possible to add a required amount of a known reducing agent. Examples of known reducing agents include hydroquinone and sodium adithionate.

[0142] (Liquid-liquid separation process)

[0143] In the method for manufacturing polyphenylene ether, water may be added to extract the compound in which the copper catalyst has been deactivated, liquid-liquid separation may be performed into an organic phase and an aqueous phase, and the copper catalyst may be removed from the organic phase by removing the aqueous phase. This liquid-liquid separation process is not particularly limited, but methods such as static separation or separation by centrifugation may be used. To facilitate the liquid-liquid separation, known surfactants may be used.

[0144] (Concentration and drying process)

[0145] Next, in the method for manufacturing 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.

[0146] Methods for volatilizing the solvent contained in the above organic phase are not specifically limited, but include a method of concentrating by transferring the organic phase to a high-temperature concentration tank and distilling off the solvent, or a method of concentrating by distilling off toluene using equipment such as a rotary evaporator.

[0147] As for the temperature of the drying treatment in the drying process, at least 60°C or higher is preferable, 80°C or higher is more preferable, 120°C or higher is even more preferable, and 140°C or higher is most preferable. If the drying of polyphenylene ether is performed 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.

[0148] To obtain polyphenylene ether with high efficiency, methods such as increasing the drying temperature, increasing the vacuum level in the drying atmosphere, and stirring during drying are effective; however, increasing the drying temperature is particularly desirable from the perspective of manufacturing efficiency. For the drying process, it is preferable to use a dryer equipped with a mixing function. Examples of mixing functions include stirring-type and electric dryers. This allows for a higher throughput, thereby maintaining high productivity.

[0149] The polyphenylene ether of the present embodiment may also be prepared by a redistribution reaction in which the polyphenylene ether derived from the phenol of formula (1) is equilibrated with the phenol compound of formula (2) in the presence of an oxidizing agent. The redistribution reaction is known in the art and is described, for example, in U.S. Patent No. 3496236 by Cooper et al. and U.S. Patent No. 5880221 by Liska et al.

[0150] (Degeneration reaction process)

[0151] There are no limitations on the method of introducing a functional group to the hydroxyl group of unmodified polyphenylene ether, and it is obtained, for example, by a reaction forming an ester bond between the hydroxyl group of unmodified polyphenylene ether and a carboxylic acid having a carbon-carbon double bond (hereinafter referred to as carboxylic acid). Various known methods can be used for forming the ester bond. Examples include a. reaction of a carboxylic acid halide with a hydroxyl group at the polymer end, b. formation of an ester bond by reaction with a carboxylic acid anhydride, c. direct reaction with a carboxylic acid, and d. methods by an ester exchange reaction. The reaction with a carboxylic acid halide is one of the most common methods. As for the carboxylic acid halide, chlorides and bromides are generally used, but other halogens may be used. The reaction may be either a direct reaction with the hydroxyl group or a reaction with an alkali metal salt of the hydroxyl group. In the direct reaction between a carboxylic acid halide and a hydroxyl group, acids such as hydrogen halides are generated; therefore, a weak base such as an amine may be co-existed to capture the acid. In the reaction with the carboxylic acid anhydride of b or the direct reaction with the carboxylic acid of c, compounds such as carbodiimides or dimethylaminopyridine may be co-existed to activate the reaction site and promote the reaction. In the case of the transesterification reaction of d, it is desirable to remove the generated alcohols as necessary. Additionally, known metal catalysts may be co-existed to promote the reaction. After the reaction, to remove by-products such as amine salts, the solution may be washed with water, an acidic or alkaline aqueous solution, or the polymer solution may be dropped into a non-solvent such as an alcohol and the target product may be recovered by redeposition. Alternatively, after washing the polymer solution, the solvent may be removed by distillation under reduced pressure and the polymer may be recovered.

[0152] The method for manufacturing modified polyphenylene ether of the present embodiment is not limited to the method for manufacturing polyfunctional modified polyphenylene ether of the present embodiment described above, and the order or number of the oxidative polymerization process, copper extraction and byproduct removal process, liquid-liquid separation process, and concentration and drying process described above may be appropriately adjusted.

[0153] (Polyphenylene ether solution)

[0154] The polyphenylene ether solution of the present embodiment comprises at least the polyphenylene ether of the present embodiment described above and a ketone-based solvent, and may also comprise other components. Additionally, as a solvent, it may comprise a solvent other than a ketone-based solvent.

[0155] Examples of the above ketone-based solvents include acetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, etc.

[0156] The ratio of the total mass of the polyphenylene ether and the ketone-based solvent to 100 mass% of the polyphenylene ether solution is preferably 80 mass% or more, more preferably 90 mass% or more, even more preferably 95 mass% or more, and particularly preferably 100 mass%.

[0157] The mass ratio of the polyphenylene ether to 100 mass% of the polyphenylene ether solution is preferably 1 to 40 mass%. In addition, the mass ratio of the ketone-based solvent to 100 mass% of the polyphenylene ether solution is preferably 60 to 99 mass%.

[0158] The above polyphenylene ether solution can be prepared, for example, by mixing the above polyphenylene ether, the above ketone-based solvent, and any other component or other solvent.

[0159] <Thermosetting composition>

[0160] The polyphenylene ether of the present embodiment can be used as a raw material for a thermosetting composition. The thermosetting composition is not particularly limited as long as it contains polyphenylene ether, but it is preferable to further include a crosslinking agent and an organic peroxide, and, if desired, may further include a thermoplastic resin, a flame retardant, other additives, a silica filler, a solvent, etc. The components of the thermosetting composition of the present embodiment are described below.

[0161] (Polyphenylene ether)

[0162] As described above, the polyphenylene ether of the present embodiment may be used as a single resin in a thermosetting composition, may be used in combination with a polyphenylene ether having a different structure, or may be used in combination with various known additives.

[0163] When used in combination with other components, the content of polyphenylene ether in the thermosetting composition is preferably 0.5 to 95 mass%, more preferably 20 to 93 mass%, and even more preferably 40 to 90 mass%.

[0164] (Crosslinking agent)

[0165] In the thermosetting composition of the present embodiment, any crosslinking agent having the ability to cause or promote a crosslinking reaction may be used.

[0166] It is preferable that the crosslinking agent 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 thermosetting composition can be suppressed, and good resin fluidity during heat molding can also be obtained.

[0167] In addition, the number average molecular weight may be a value measured by a general molecular weight measurement method, and specifically, a value measured using GPC, etc.

[0168] From the perspective of the crosslinking reaction, it is preferable for the crosslinking agent to have an average of at least two carbon-carbon unsaturated double bonds per molecule. The crosslinking agent may be composed of one type of compound or may be composed of two or more types of compounds.

[0169] In addition, the term "carbon-carbon unsaturated double bond" as used in this specification refers to a double bond located at a branched end from the main chain when the crosslinking agent is a polymer or oligomer. Examples of carbon-carbon unsaturated double bonds include, for instance, the 1,2-vinyl bond in polybutadiene.

[0170] When the number average molecular weight of the crosslinking agent is less than 600, it is preferable that the number of carbon-carbon unsaturated double bonds per molecule of the crosslinking agent (average value) is 2 to 4. When the number average molecular weight of the crosslinking agent is 600 or more and less than 1,500, it is preferable that the number of carbon-carbon unsaturated double bonds per molecule of the crosslinking agent (average value) is 4 to 26. When the number average molecular weight of the crosslinking agent is 1,500 or more and less than 4,000, it is preferable that the number of carbon-carbon unsaturated double bonds per molecule of the crosslinking agent (average value) is 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 greater than or equal to the above specific value, thereby further increasing the reactivity of the crosslinking agent in the thermosetting composition of the present embodiment, the crosslinking density of the cured product of the thermosetting composition is further improved, and as a result, further excellent heat resistance can be imparted. 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 less than or equal to the above specific value, thereby providing even better resin fluidity during heat molding.

[0171] Examples of crosslinking agents include, for instance, trialanyl isocyanurate compounds such as trialyl isocyanurate (TAIC), trialanyl cyanurate compounds such as trialyl cyanurate (TAC), 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 having vinylbenzyl groups in the molecule such as divinylbenzene, and polyfunctional maleimide compounds having two or more maleimide groups in the molecule such as 4,4'-bismaleimidediphenylmethane. These crosslinking agents are used either alone or in combination of two or more. Among these, it is preferable that the crosslinking agent comprises at least one compound selected from the group consisting of trialyl cyanurate, trialyl isocyanurate, and polybutadiene. By including at least one compound described above as the crosslinking agent, the thermosetting composition has better compatibility and coating properties with the crosslinking agent and polyphenylene ether, and when mounted on an electronic circuit board, the substrate properties tend to be better.

[0172] The mass ratio of polyphenylene ether to crosslinking agent (polyphenylene ether:crosslinking agent) is preferably 25:75 to 95:5, and more preferably 32:68 to 85:15, in order to further improve the compatibility between the crosslinking agent and the modified polyphenylene ether, the coating properties of the thermosetting composition, and the characteristics of the mounted electronic circuit board.

[0173] (Organic peroxide)

[0174] In this embodiment, any organic peroxide having the ability to promote the polymerization reaction of a thermosetting composition comprising polyphenylene ether and a crosslinking agent may be used. As organic peroxides, for example, benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-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, trimethylsilyltriphenylsilyl peroxide Examples of peroxides include those mentioned above. Additionally, radical generators such as 2,3-dimethyl-2,3-diphenylbutane can be used as reaction initiators for thermosetting compositions. Among these, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, di(2-t-butylperoxyisopropyl)benzene, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexane are preferred in terms of providing a cured product with excellent heat resistance and mechanical properties and a lower dielectric loss tangent (it is also desirable that the dielectric constant is low).

[0175] The half-life temperature of the organic peroxide in one minute is preferably 155 to 185°C, more preferably 160 to 180°C, and even more preferably 165 to 175°C. By having the half-life temperature of the organic peroxide in one minute within the range of 155 to 185°C, the compatibility between the organic peroxide and the modified PPE, the coating properties of the thermosetting composition, and the characteristics of the mounted electronic circuit board tend to be even better.

[0176] In addition, in this specification, the half-life temperature in one minute is the temperature at which the time for an organic peroxide to decompose and its active oxygen content to be reduced to half is one minute. The half-life temperature in one minute is a value confirmed by dissolving an organic peroxide in a solvent inert to radicals, such as benzene, to a concentration of 0.05 to 0.1 mol / L, and thermally decomposing the organic peroxide solution under a nitrogen atmosphere.

[0177] Organic peroxides having a half-life temperature in the range of 155 to 185°C in 1 minute include, for example, 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 (159.9°C), 2,2-di-(t-butylperoxy)butane (159.9°C), Examples include t-butylperoxybenzoate (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), and t-butylcumyl peroxide (173.3°C).

[0178] 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 part by mass or more, and even more preferably 1.5 parts by mass or more, based on 100 parts by mass of the total of polyphenylene ether and crosslinking agent, in order to ensure better compatibility between the organic peroxide and the modified PPE and better coating properties of the thermosetting composition; and is preferably 5 parts by mass or less, more preferably 4.5 parts by mass or less, in order to ensure excellent substrate properties when the thermosetting composition is mounted on an electronic circuit board.

[0179] (Thermoplastic resin)

[0180] The thermoplastic resin is preferably at least one selected from the group consisting of a block copolymer of a vinyl aromatic compound and an olefinic alkene compound, a hydrogenated product thereof (a hydrogenated block copolymer obtained by hydrogenating a block copolymer of a vinyl aromatic compound and an olefinic alkene compound), and a homopolymer of a vinyl aromatic compound.

[0181] In addition, the weight average molecular weight of the thermoplastic resin is preferably greater than 50,000 and less than or equal to 780,000, more preferably 60,000 to 750,000, and even more preferably 70,000 to 700,000, in terms of compatibility with polyphenylene ether, resin fluidity, coating properties of the thermosetting composition, and heat resistance during curing.

[0182] When a thermosetting composition includes polyphenylene ether, a crosslinking agent, and an organic peroxide, and a thermoplastic resin having the type and weight average molecular weight described above, the compatibility with other components of the modified PPE and the coating properties on the substrate, etc. tend to be good, and furthermore, the substrate properties when embedded in an electronic circuit board can also be excellent.

[0183] In addition, the weight-average molecular weight is obtained by the method described in the examples below.

[0184] The content of units derived from vinyl aromatic compounds in the above block copolymer or its hydrogenated additive is preferably 20 mass% or more with respect to the lower limit, and more preferably 22 mass% or more, 24 mass% or more, 26 mass% or more, 28 mass% or more, 30 mass% or more, and 32 mass% or more. In addition, it is preferably 70 mass% or less with respect to the upper limit, and more preferably 69 mass% or less, 68 mass% or less, and 67 mass% or less. By having the content of units derived from vinyl aromatic compounds in the above block copolymer or its hydrogenated additive be 20 to 70 mass%, compatibility with modified polyphenylene ether is further improved, and / or adhesion strength with metal foil tends to be further improved.

[0185] As vinyl aromatic compounds, they may have an aromatic ring and a vinyl group within the molecule, and examples include styrene.

[0186] As olefinic alkene compounds, any alkene having a straight or branched structure within the molecule may be used, such as ethylene, propylene, butylene, isobutylene, butadiene, and isoprene.

[0187] As for the thermoplastic resin, in terms of having even better compatibility with polyphenylene ether, it is preferable to be at least one selected from the group consisting of styrene-butadiene block copolymer, styrene-ethylene-butadiene block copolymer, styrene-ethylene-butylene block copolymer, styrene-butadiene-butylene block copolymer, styrene-isoprene block copolymer, styrene-ethylene-propylene block copolymer, styrene-isobutylene block copolymer, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-ethylene-butadiene block copolymer, hydrogenated styrene-butadiene-butylene block copolymer, hydrogenated styrene-isoprene block copolymer, and homopolymer of styrene (polystyrene); and styrene-butadiene block copolymer, hydrogenated styrene-butadiene block copolymer, and It is more preferable that it be one or more types selected from the group consisting of polystyrene.

[0188] The hydrogenation rate in the above hydrogenated product is not particularly limited, and some carbon-carbon unsaturated double bonds derived from olefinic alkenes may remain.

[0189] The content of the thermoplastic resin is preferably 2 to 20 parts by mass based on 100 parts by mass of the total of polyphenylene ether and the crosslinking agent, more preferably 3 to 19 parts by mass, even more preferably 4 to 18 parts by mass, and particularly preferably 5 to 17 parts by mass. By having this content within the above numerical range, the thermosetting composition of the present embodiment has even better compatibility and coating properties between the thermoplastic resin and the modified polyphenylene ether, and tends to have even better substrate properties when mounted on an electronic circuit board.

[0190] In addition, the thermosetting composition of the present embodiment may include a thermoplastic resin other than the thermoplastic resin having the type and weight average molecular weight described above.

[0191] (Flame retardant)

[0192] The thermosetting composition of the present embodiment preferably includes a flame retardant. As for the flame retardant, it is not particularly limited as long as it does not mix with other components contained in the thermosetting composition after curing, from the viewpoint that it can improve heat resistance. Preferably, the flame retardant does not mix with polyphenylene ether and / or crosslinking agent in the thermosetting composition after curing.

[0193] Examples of flame retardants include inorganic flame retardants such as antimony trioxide, aluminum hydroxide, magnesium hydroxide, and zinc borate; aromatic bromine compounds such as hexabromobenzene, decabromodiphenylethane, 4,4-dibromobiphenyl, and ethylenebistetrabromophthalimide; and phosphorus-based flame retardants such as resorcinolbis-diphenylphosphate and resorcinolbis-dicylenylphosphate. These flame retardants may be used individually or in combination of two or more types. Among these, decabromodiphenylethane is preferred as the flame retardant because it offers superior compatibility between the flame retardant and the modified PPE, coating properties of the thermosetting composition, and characteristics of the mounted electronic circuit board.

[0194] The content of the flame retardant is not particularly limited, but in terms of maintaining flame retardancy at the V-0 level of UL Standard 94, it is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, and even more preferably 15 parts by weight or more, with respect to 100 parts by weight of the total of polyphenylene ether and crosslinking agent. In addition, in terms of maintaining a low dielectric loss tangent of the obtained cured product (preferably also maintaining a low dielectric constant), the content of the flame retardant is preferably 50 parts by weight or less, more preferably 45 parts by weight or less, and even more preferably 40 parts by weight or less.

[0195] (Silica Filler)

[0196] The thermosetting composition of the present embodiment may contain a silica filler. Examples of silica fillers include natural silica, fused silica, synthetic silica, amorphous silica, aerosil, and hollow silica.

[0197] The content of the silica filler may be 10 to 100 parts by mass per 100 parts by mass of the total of the polyphenylene ether and the crosslinking agent. In addition, the silica filler may be surface-treated using a silane coupling agent or the like on its surface.

[0198] The thermosetting composition of the present embodiment may further include, in addition to the flame retardant and silica filler, additives such as a heat stabilizer, antioxidant, UV absorber, surfactant, lubricant, solvent, etc.

[0199] In the case where the thermosetting composition of the present embodiment includes a solvent, the solid component in the thermosetting composition may be in the form of a varnish in which the solid component is dissolved or dispersed in the solvent, and a resin film may also be formed from the thermosetting composition of the present embodiment.

[0200] (solvent)

[0201] As solvents, aromatic compounds such as toluene and xylene, methyl ethyl ketone (MEK), cyclopentanone, cyclohexanone, and chloroform are preferred in terms of solubility. These solvents may be used individually or in combination of two or more.

[0202] Prepreg

[0203] Preferred according to the present embodiment comprises a substrate and the thermosetting composition of the present embodiment described above, and preferably is a composite comprising a substrate and the thermosetting composition of the present embodiment impregnated or coated onto the substrate. The prepreg is obtained by impregnating a substrate, such as glass cloth, with a varnish of the thermosetting composition and then drying and removing the solvent using a hot air dryer or the like.

[0204] Examples of substrates include various glass cloths such as roving cloth, cloth, chopped mat, surfing 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, azab, and felt; natural cellulose-based substrates such as carbon fiber cloth, kraft paper, cotton paper, and cloth obtained from paper-glass blended yarns; and polytetrafluoroethylene porous films. Among these, glass cloth is preferred. These substrates may be used as a single type or in combination of two or more types.

[0205] The proportion of the solid content of the thermosetting composition (components other than the solvent of the thermosetting composition) in the prepreg of the present embodiment is preferably 30 to 80 mass%, and more preferably 40 to 70 mass%. When the above proportion is 30 mass% or more, the insulation reliability tends to be even better when the prepreg is used for electronic substrates, etc. When the above proportion is 80 mass% or less, mechanical properties such as bending modulus tend to be even better for applications such as electronic substrates.

[0206] Laminated structure

[0207] The laminate of the present embodiment preferably comprises the cured prepreg of the present embodiment described above and a metal foil, and is a metal-coated laminate obtained by laminating and curing the thermosetting composition of the present embodiment or the prepreg of the present embodiment and the metal foil. The metal-coated laminate preferably has a form in which the cured prepreg (hereinafter also referred to as a "cured composite") and the metal foil are laminated and closely bonded, and is suitable for use as a material for electronic substrates.

[0208] Examples of metal foils include aluminum foil and copper foil; among these, copper foil is preferred because it has low electrical resistance.

[0209] The cured composite combined with the metal foil may be a single sheet or multiple sheets, and depending on the application, the metal foil is overlapped on one or both sides of the composite to be processed into a laminated board.

[0210] As a method for manufacturing a metal-clad laminate, for example, a composite (e.g., the prepreg described above) composed of a thermosetting composition and a substrate is formed, and then the composite is overlapped with a metal foil and the thermosetting composition is cured to obtain a laminate in which a cured laminate and a metal foil are laminated.

[0211] One particularly preferred application of the above-mentioned metal-clad laminate is a printed circuit board. In the printed circuit board, it is preferable that at least a portion of the metal foil is removed from the metal-clad laminate.

[0212] Printed Wiring Board

[0213] At least a portion of the metal foil can be removed from the above-described metal-clad laminate to form a printed circuit board. Typically, the printed circuit board can be formed by a pressure heat molding method using the prepreg of the present embodiment described above. As a substrate, the same as that described above regarding the prepreg can be used.

[0214] The above printed circuit board, by including the thermosetting composition of the present embodiment, possesses excellent heat resistance and electrical properties (low dielectric loss tangent and / or low dielectric constant), and furthermore, is capable of suppressing variations in electrical properties associated with environmental fluctuations, and further possesses excellent insulation reliability and mechanical properties.

[0215] Examples

[0216] The present embodiment will be described in more detail below based on the examples, but the present embodiment is not limited to the following examples.

[0217] First, the measurement methods and evaluation criteria for each physical property and evaluation are explained below.

[0218] (1) Molar ratio of repeating units derived from the phenol of Formula (1) or Formula (2) to the sum of repeating units derived from the phenol of Formula (1) and repeating units derived from the phenol of Formula (2) contained in the unmodified polyphenylene ether

[0219] The unmodified polyphenylene ether obtained in the examples and comparative examples was dissolved in dichloroform, and tetramethylsilane was used as an internal standard 1 H-NMR measurements were performed (500 MHz manufactured by JEOL). For the measurements, volatile components such as toluene and water were removed from the polyphenylene ether by maintaining it at 140°C and 1 mmHg for 8 hours beforehand, and the measurements were performed using the unmodified polyphenylene ether in a dry state. The signals of the units derived from phenol in Equations (1) and (2) were identified, and the respective ratios were calculated.

[0220] For example, regarding the unmodified polyphenylene ethers obtained in the examples and comparative examples, the attribution method of the repeating unit derived from the phenol of Formula (1), i.e., the 2,6-dimethylphenol-derived structure (2,6-dimethylphenylene unit), and the repeating unit derived from the phenol of Formula (2), i.e., the 2-tert-butyl-5-methylphenol-derived structure (2-tert-butyl-5-methylphenylene unit), was interpreted as follows. The peaks of the repeating units derived from each phenol appear in the following regions.

[0221] Peaks derived from hydrogen atoms of the methyl groups of 2,6-dimethylphenylene units and 2-tert-butyl-5-methylphenylene units (6H and 3H, respectively): 1.60 to 2.50 ppm (excluding peaks derived from hydrogen atoms of the methyl groups of toluene)

[0222] Peak derived from the hydrogen atom of the tert-butyl group of the 2-tert-butyl-5-methylphenylene unit (9H): 1.00 to 1.52 ppm (excluding the peak derived from the hydrogen atom of water)

[0223] The integral value of the above signal can be examined, and the integral value per proton of the peak derived from the hydrogen atom of the methyl group of the 2,6-dimethylphenylene unit can be obtained by the following formula (1).

[0224] E={C-3×(D / 9)} / 6 … Formula (1)

[0225] C: Integrated value of the methyl-derived peaks of the 2,6-dimethylphenylene unit and the 2-tert-butyl-5-methylphenylene unit

[0226] D: Integrated value of the tert-butyl derived peak of the 2-tert-butyl-5-methylphenylene unit

[0227] E: Integral value per proton of the methyl-derived peak of the 2,6-dimethylphenylene unit

[0228] In addition, the ratio (mol%) of repeating units derived from the phenol of formula (1) or formula (2) can be calculated by the following formulas (2) and (3).

[0229] The ratio of repeating units (mol%) derived from phenol in Equation (1) = E / {(D / 9)+E}×100 … Equation (2)

[0230] The ratio of repeating units (mol%) derived from phenol in Equation (2) = (D / 9) / {(D / 9)+E}×100 … Equation (3)

[0231] (2) Molar ratio of repeating unit derived from impurity A to the sum of repeating unit derived from phenol of Formula (1), repeating unit derived from phenol of Formula (2), and repeating unit derived from impurity A, contained in the unmodified polyphenylene ether

[0232] The unmodified polyphenylene ether obtained in the examples and comparative examples was dissolved in dichloroform, and tetramethylsilane was used as an internal standard 1H-NMR measurements were performed (500 MHz manufactured by JEOL). For the measurements, volatile components such as toluene and water were removed from the polyphenylene ether by maintaining it at 140°C and 1 mmHg for 8 hours beforehand, and the measurements were performed using the unmodified polyphenylene ether in a dry state. The signals of the units derived from Equation (1), Equation (2) and the phenol of impurity A were identified, and the respective ratios were calculated.

[0233] For example, in the unmodified polyphenylene ether obtained in the examples and comparative examples, a repeating unit derived from the phenol of Formula (1), i.e., a signal derived from a structure derived from 2,6-dimethylphenol (2,6-dimethylphenylene unit), a repeating unit derived from the phenol of Formula (2), i.e., a signal derived from a structure derived from 2-tert-butyl-5-methylphenol (2-tert-butyl-5-methylphenylene unit), and a repeating unit derived from impurity A, i.e., R in Formula (11). 11 =methyl group, R 12 = The attribution method of the signal originating from the repeating unit with hydrogen atom and z=0 was interpreted as follows. The peaks of the repeating units derived from each phenol appear in the following regions.

[0234] 2,6-dimethylphenylene unit, 2-tert-butyl-5-methylphenylene unit and R in formula (11) 11 =methyl group, R 12 = Peaks originating from the hydrogen atom of the methyl group of the signal derived from the repeating unit with z=0, hydrogen atom (6H, 3H, and 12H, respectively): 1.60 to 2.50 ppm (excluding peaks originating from the hydrogen atom of the methyl group of toluene)

[0235] Peak derived from the hydrogen atom of the tert-butyl group of the 2-tert-butyl-5-methylphenylene unit (9H): 1.00 to 1.52 ppm (excluding the peak derived from the hydrogen atom of water)

[0236] R in Equation (11) 11 =methyl group, R 12=Hydrogen atom, peak derived from the hydrogen atom of the methyl group of the repeating unit with z=0 (4H): 7.35 ppm

[0237] The integral value of the above signal can be examined, and the integral value per proton of the peak derived from the hydrogen atom of the methyl group of the 2,6-dimethylphenylene unit can be obtained by the following formula (4).

[0238] E={C-3×(D / 9)-12×(F / 4)} / 6… Equation (4)

[0239] C: Integrated value of the methyl-derived peaks of the 2,6-dimethylphenylene unit and the 2-tert-butyl-5-methylphenylene unit

[0240] D: Integrated value of the tert-butyl derived peak of the 2-tert-butyl-5-methylphenylene unit

[0241] F: R in Equation (11) 11 =methyl group, R 12 = Hydrogen atom, integral value of the peak originating from the hydrogen atom of the benzene ring repeating unit with z=0

[0242] E: Integral value per proton of the methyl-derived peak of the 2,6-dimethylphenylene unit

[0243] Also, by the following formula (5), R in formula (11) 11 =methyl group, R 12 = You can calculate the proportion (mol%) of hydrogen atoms and structures where z=0.

[0244] R in Equation (11) 11 =methyl group, R 12 = Proportion of repeating units with hydrogen atoms, z=0 (mol%) = (F / 4) / {(D / 9)+E+(F / 4)}×100 … Formula (5)

[0245] (3) The molar ratio of the repeating unit derived from the monovalent phenol having at least one unsaturated hydrocarbon group at the ortho-position of the carbon atom to which the hydroxyl group of the phenol is bonded, to the sum of the repeating unit derived from the phenol of formula (1) included in the unmodified polyphenylene ether and the repeating unit derived from the monovalent phenol having at least one unsaturated hydrocarbon group at the ortho-position of the carbon atom to which the hydroxyl group of the phenol is bonded.

[0246] The unmodified polyphenylene ether obtained in the examples and comparative examples was dissolved in dichloroform, and tetramethylsilane was used as an internal standard, 1 H-NMR measurements were performed using a JEOL 500 MHz device. For the measurements, volatile components such as toluene and water were removed by maintaining the polyphenylene ether at 140°C and 1 mmHg for 8 hours prior to measurement, and the measurements were performed using the unmodified polyphenylene ether in a dry state. The repeating unit derived from the phenol of Formula (1), the repeating unit derived from the phenol of Formula (2), and the repeating unit derived from a monovalent phenol having at least one unsaturated hydrocarbon group at the ortho position of the carbon atom to which the hydroxyl group of the phenol is bonded were identified, and the respective ratios were calculated.

[0247] For example, in the unmodified polyphenylene ether obtained in the examples and comparative examples, the signal derived from the repeating unit derived from the phenol of Formula (1), i.e., the structure derived from 2,6-dimethylphenol (2,6-dimethylphenylene unit), the signal derived from the repeating unit derived from the phenol of Formula (2), i.e., the structure derived from 2-tert-butyl-5-methylphenol (2-tert-butyl-5-methylphenylene unit), and the signal derived from the repeating unit derived from the monovalent phenol having at least one unsaturated hydrocarbon group at the ortho position of the carbon atom to which the hydroxyl group of the phenol is bonded, i.e., the structure derived from 2-allylphenol (2-arylphenylene unit) appear in the following region.

[0248] Peaks derived from hydrogen atoms of the methyl groups of 2,6-dimethylphenylene units and 2-tert-butyl-5-methylphenylene units (6H and 3H, respectively): 1.60 to 2.50 ppm (excluding peaks derived from hydrogen atoms of the methyl groups of toluene)

[0249] Peak derived from the hydrogen atom of the tert-butyl group of the 2-tert-butyl-5-methylphenylene unit (9H): 1.00 to 1.52 ppm (excluding the peak derived from the hydrogen atom of water)

[0250] Peak derived from the hydrogen atom of the methylene group of the 2-arylphenylene unit (2H): 3.40 ppm

[0251] The integral value of the above signal can be examined, and the integral value per proton of the peak derived from the hydrogen atom of the methyl group of the 2,6-dimethylphenylene unit can be obtained by the following formula (6).

[0252] E={C-3×(D / 9)} / 6 … Formula (6)

[0253] C: Integrated value of the methyl-derived peaks of the 2,6-dimethylphenylene unit and the 2-tert-butyl-5-methylphenylene unit

[0254] D: Integrated value of the tert-butyl derived peak of the 2-tert-butyl-5-methylphenylene unit

[0255] E: Integral value per proton of the methyl-derived peak of the 2,6-dimethylphenylene unit

[0256] In addition, the ratio (mol%) of 2-arylphenylene units can be calculated by the following formula (7).

[0257] Proportion of 2-arylphenylene units (mol%) = (G / 2) / {E+(G / 2)}×100 … Formula (7)

[0258] G: Integral value per proton of the peak derived from the methylene group of the 2-arylphenylene unit

[0259] (4) Molar ratio of the repeating unit derived from the phenol of Formula (1) or Formula (2) to the sum of the repeating unit derived from the phenol of Formula (1) and the repeating unit derived from the phenol of Formula (2) included in the modified polyphenylene ether

[0260] The modified polyphenylene ether was carried out as follows.

[0261] The modified polyphenylene ethers obtained in the examples and comparative examples were dissolved in a measurement solvent (dichloroform with one drop of heavy water added to remove hydroxyl groups), and tetramethylsilane was used as an internal standard, 1 H-NMR measurements were performed (500 MHz manufactured by JEOL). For the measurements, volatile components such as toluene and water were removed from the polyphenylene ether by maintaining it at 80°C and 1 mmHg for 8 hours beforehand, and the measurements were performed using the modified polyphenylene ether in a dry state. The signals of the units derived from phenol in Equations (1) and (2) were identified, and the respective ratios were calculated.

[0262] For example, regarding the modified polyphenylene ethers obtained in the examples and comparative examples, the attribution method of the repeating unit derived from the phenol of Formula (1), i.e., the signal derived from the 2,6-dimethylphenol-derived structure (2,6-dimethylphenylene unit), the repeating unit derived from the phenol of Formula (2), i.e., the signal derived from the 2-tert-butyl-5-methylphenol-derived structure (2-tert-butyl-5-methylphenylene unit), and the signal derived from a partial structure selected from the group consisting of Formulas (4), (5), (6), or (7), i.e., the signal derived from the methacrylic group-derived structure, was interpreted as follows. The peaks of the repeating units derived from each phenol appear in the following regions.

[0263] Peaks derived from hydrogen atoms of the methyl group of 2,6-dimethylphenylene unit, 2-tert-butyl-5-methylphenylene unit, and methyl group of methacrylate (6H, 3H, and 3H, respectively): 1.60 to 2.50 ppm (excluding peaks derived from hydrogen atoms of the methyl group of toluene)

[0264] Peak derived from the hydrogen atom of the tert-butyl group of the 2-tert-butyl-5-methylphenylene unit (9H): 1.00 to 1.52 ppm (excluding the peak derived from the hydrogen atom of water)

[0265] Peak derived from one hydrogen atom of the methylene group of the methacrylic group (1H): 4.4 to 5.8 ppm

[0266] The integral value of the above signal can be examined, and the integral value per proton of the peak derived from the hydrogen atom of the methyl group of the 2,6-dimethylphenylene unit can be obtained by the following formula (8).

[0267] E={C-3×(D / 9)-3×(H / 1)} / 6 … Formula (8)

[0268] C: Integrated value of the methyl-derived peaks of the 2,6-dimethylphenylene unit and the 2-tert-butyl-5-methylphenylene unit

[0269] D: Integrated value of the tert-butyl derived peak of the 2-tert-butyl-5-methylphenylene unit

[0270] E: Integral value per proton of the methyl-derived peak of the 2,6-dimethylphenylene unit

[0271] H: Integral value of the peak originating from one hydrogen atom of the methylene group of the methacrylate group

[0272] In addition, the ratio (mol%) of repeating units derived from the phenol of formula (1) or formula (2) can be calculated by the following formulas (9) and (10).

[0273] The ratio of repeating units (mol%) derived from the phenol in Equation (1) = E / {(D / 9)+E}×100 … Equation (9)

[0274] The ratio of repeating units (mol%) derived from the phenol in Equation (2) = (D / 9) / {(D / 9)+E}×100 … Equation (10)

[0275] (5) Molar ratio of repeating unit derived from impurity A to the sum of repeating unit derived from phenol of Formula (1), repeating unit derived from phenol of Formula (2), and repeating unit derived from impurity A, included in the modified polyphenylene ether

[0276] The unmodified polyphenylene ether obtained in the examples and comparative examples was dissolved in a measurement solvent (dichloroform with one drop of heavy water added to remove hydroxyl groups), and tetramethylsilane was used as an internal standard, 1 H-NMR measurements were performed (500 MHz manufactured by JEOL). For the measurements, volatile components such as toluene and water were removed from the polyphenylene ether by maintaining it at 80°C and 1 mmHg for 8 hours beforehand, and the measurements were performed using the unmodified polyphenylene ether in a dry state. The signals of the units derived from Equation (1), Equation (2) and the phenol of impurity A were identified, and the respective ratios were calculated.

[0277] For example, in the unmodified polyphenylene ether obtained in the examples and comparative examples, a signal derived from a repeating unit derived from the phenol of Formula (1), i.e., a signal derived from a structure derived from 2,6-dimethylphenol (2,6-dimethylphenylene unit), a repeating unit derived from the phenol of Formula (2), i.e., a signal derived from a structure derived from 2-tert-butyl-5-methylphenol (2-tert-butyl-5-methylphenylene unit), a signal derived from a partial structure selected from the group consisting of Formulas (4), (5), (6), or (7), i.e., a signal derived from a structure derived from a methacrylic group, and a repeating unit derived from impurity A, i.e., R in Formula (11). 11 =methyl group, R 12= The attribution method of the signal originating from the repeating unit with hydrogen atom and z=0 was interpreted as follows. The peaks of the repeating units derived from each phenol appear in the following regions.

[0278] 2,6-dimethylphenylene unit, 2-tert-butyl-5-methylphenylene unit, R in formula (11) 11 =methyl group, R 12 = Hydrogen atom, repeating unit with z=0, peaks derived from the hydrogen atom of the methyl group of the signal originating from the methacrylate group (6H, 3H, 12H, and 3H, respectively): 1.60 to 2.50 ppm (excluding peaks derived from the hydrogen atom of the methyl group of toluene)

[0279] Peak derived from the hydrogen atom of the tert-butyl group of the 2-tert-butyl-5-methylphenylene unit (9H): 1.00 to 1.52 ppm (excluding the peak derived from the hydrogen atom of water)

[0280] R in Equation (11) 11 =methyl group, R 12 =Hydrogen atom, peak derived from the hydrogen atom of the methyl group of the repeating unit with z=0 (4H): 7.35 ppm

[0281] Peak derived from one hydrogen atom of the methylene group of the methacrylic group (1H): 4.4 to 5.8 ppm

[0282] The integral value of the above signal can be examined, and the integral value per proton of the peak derived from the hydrogen atom of the methyl group of the 2,6-dimethylphenylene unit can be obtained by the following formula (11).

[0283] E={C-3×(D / 9)-12×(F / 4)-3×(H / 1)} / 6 … Formula (11)

[0284] C: Integrated value of the methyl-derived peaks of the 2,6-dimethylphenylene unit and the 2-tert-butyl-5-methylphenylene unit

[0285] D: Integrated value of the tert-butyl derived peak of the 2-tert-butyl-5-methylphenylene unit

[0286] F: R in Equation (11) 11 =methyl group, R 12 = Hydrogen atom, integral value of the peak originating from the hydrogen atom of the benzene ring repeating unit with z=0

[0287] E: Integral value per proton of the methyl-derived peak of the 2,6-dimethylphenylene unit

[0288] H: Integral value of the peak originating from one hydrogen atom of the methylene group of the methacrylate group

[0289] Also, by the following formula (12), R in formula (11) 11 =methyl group, R 12 = You can calculate the proportion (mol%) of hydrogen atoms and structures where z=0.

[0290] R in Equation (11) 11 =methyl group, R 12 = Proportion of repeating units with hydrogen atoms, z=0 (mol%) = (F / 4) / {(D / 9)+E+(F / 4)}×100 … Formula (12)

[0291] (6) Reduction viscosity (ηsp / c)

[0292] A 0.5 g / dL chloroform solution was prepared in polyphenylene ether, and the reduction viscosity (ηsp / c) (dL / g) at 30°C was determined using a Ubelohde viscometer.

[0293] (7) Average number of hydroxyl groups in polyphenylene ether

[0294] 5.0 mg of polyphenylene ether was weighed. Then, the weighed polyphenylene ether was dissolved in 25 mL of methylene chloride. After adding 150 μL of an ethanol solution of 2 mass% tetraethylammonium hydroxide (TEAH) to 2.0 mL of the prepared solution, the absorbance (Abs) at 318 nm was measured using a UV spectrophotometer (Hitachi Seisakusho: U-3210 type) (using an absorbance measurement cell with a cell length of 1 cm). Based on the measurement results, the hydroxyl equivalent obtained from the absorbance was calculated using the following formula (13). Additionally, the average number of hydroxyl groups per molecule of polyphenylene ether was calculated using the number average molecular weight obtained by gel permeation chromatography (details are described in (8) below).

[0295] Hydroxyl equivalent (g / mol) obtained from absorbance = [(ε×5) / (25×Abs)] … Formula (13)

[0296] (Here, ε represents the absorption coefficient and is 4700 L / mol·cm)

[0297] Average number of hydroxyl groups per molecule of polyphenylene ether (groups / molecule) = (number average molecular weight obtained using gel permeation chromatography) / (hydroxyl equivalent obtained from absorbance) … Formula (14)

[0298] (8) Number average molecular weight (Mn)

[0299] As a measuring device, a gel permeation chromatography System 21 manufactured by Showa Denko Co., Ltd. was used to prepare a calibration curve using standard polystyrene and ethylbenzene, and the number average molecular weight (Mn) of the obtained modified polyphenylene ether was measured using this calibration curve. As standard polystyrene, 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 were used.

[0300] Two K-805L columns manufactured by Showa Denko Co., Ltd. connected in series were used. Chloroform was used as the solvent, and measurements were taken with a solvent flow rate of 1.0 mL / min and a column temperature of 40°C. As the sample for measurement, a 1 g / L chloroform solution of modified polyphenylene ether was prepared and used. The UV wavelength of the detector was set to 254 nm for standard polystyrene and 283 nm for polyphenylene ether.

[0301] Based on the above measurement data, the number average molecular weight (Mn) (g / mol) was calculated from the ratio of peak areas based on the curve representing the molecular weight distribution obtained by GPC.

[0302] (9) Long-term solubility in methyl ethyl ketone (MEK solubility)

[0303] 1.5 g of polyphenylene ether and 8.5 g of methyl ethyl ketone were weighed into a transparent glass screw tube. The mixture was mixed at 20°C using a stirrer and a magnetic stirring rod. After one day, the solution was judged as “○” (good) if it maintained transparency, “×” (poor) if it did not dissolve clearly or if there was a large amount of insoluble matter, and “△” if it dissolved slightly and the remainder remained (if there was slight turbidity).

[0304] (10) Long-term solubility in toluene (TL solubility)

[0305] 2g of polyphenylene ether and 8g of toluene were weighed into a transparent glass screw tube. The mixture was mixed at 20°C using a stirrer and a magnetic stirring rod. After one day, the solution was judged as “○” (good) if it maintained transparency, “×” (poor) if it was not clearly dissolved or if there was a large amount of insoluble matter, and “△” if it was slightly dissolved and the remainder remained (if there was slight turbidity).

[0306] (11) Dielectric loss tangent of the cured product of the thermosetting composition

[0307] The dielectric loss tangent at 10 GHz of the laminates prepared in the examples and comparative examples was measured using the cavity resonance method. As measuring devices, a network analyzer (N5230A, manufactured by Agilent Technologies) and a cavity resonator (Cavity Resonator CP series) manufactured by Kanto Denshi Oyo Kaihatsu Co., Ltd. were used. The laminates were cut into rectangular shapes with a width of approximately 2 mm, a length of 50 mm, and a thickness of approximately 0.5 mm, such that the longer side of the glass cloth was the longer side. Next, they were placed in an oven at 105°C ± 2°C and dried for 2 hours, and then left to stand for 24 ± 5 ​​hours in an environment of 23°C and 50 ± 5% relative humidity. After that, the dielectric loss tangent was measured using the above measuring device in an environment of 23°C and 50 ± 5% relative humidity.

[0308] Hereinafter, the method for preparing polyphenylene ethers of each example and comparative example is described.

[0309] (Example 1)

[0310] A 40-liter jacketed polymerization vessel equipped with a spurger for introducing oxygen-containing gas at the bottom of the vessel, stirring turbine blades, and baffles, and equipped with a reflux cooler in the vent gas line at the top of the polymerization vessel, was prepared by adding 2.4 g of cuprous oxide, 18.1 g of a 47 mass% aqueous solution of hydrogen bromide, 5.8 g of di-t-butylethylenediamine, 28.1 g of di-n-butylamine, 85.6 g of butyldimethylamine, 17.9 kg of toluene, 1497 g of 2,6-dimethylphenol, and 503 g of 2-tert-butyl-5-methylphenol while blowing nitrogen gas at a flow rate of 17.1 L / min, and making a homogeneous solution. Next, dry air was introduced into the polymerization vessel from the spurger at a rate of 10.5 L / min, and polymerization was started. Dry air was passed through for 120 minutes to obtain a polymerization mixture. In addition, the temperature was controlled to 20°C during polymerization. At the end of polymerization, the polymerization mixture (polymerization solution) was in a homogeneous solution state.

[0311] The aeration of dry air was stopped, and 25.9 g of sodium ethylenediamine tetraacetate (reagent manufactured by Tojin Kagaku Genkyusho Co., Ltd.) was added to the polymerization mixture as an aqueous solution in 2 kg of water. The polymerization mixture was stirred at 70°C for 150 minutes, then left to stand for 20 minutes, and the organic phase and aqueous phase were separated by liquid-liquid separation. The organic phase was concentrated using a rotary evaporator until the polymer concentration reached 25 mass%.

[0312] The above solution was mixed with methanol such that the ratio of methanol to the polymer solution was 6, and the polymer was precipitated. Wet polyphenylene ether was obtained by vacuum filtration using a glass filter. Additionally, the wet polyphenylene ether was washed with an amount of methanol such that the ratio of methanol to the wet polyphenylene ether was 3. This washing operation was performed three times. Subsequently, the wet polyphenylene ether was maintained at 140°C and 1 mmHg for 120 minutes, and a dry polyphenylene ether was obtained.

[0313] Each measurement was performed on the obtained polyphenylene ether by the method described above. The results of each analysis are shown in Table 1.

[0314] (Example 2)

[0315] The operation was carried out in the same manner as in Example 1, except that the phenol raw materials were 1269g of 2,6-dimethylphenol and 731g of 2-tert-butyl-5-methylphenol.

[0316] Each analysis result is shown in Table 1.

[0317] (Example 3)

[0318] The operation was carried out in the same manner as in Example 1, except that the phenol raw materials were 853g of 2,6-dimethylphenol and 1147g of 2-tert-butyl-5-methylphenol.

[0319] Each analysis result is shown in Table 1.

[0320] (Example 4)

[0321] The operation was carried out in the same manner as in Example 1, except that the phenol raw materials were 454g of 2,6-dimethylphenol and 1517g of 2-tert-butyl-5-methylphenol.

[0322] Each analysis result is shown in Table 1.

[0323] (Example 5)

[0324] The operation was carried out in the same manner as in Example 1, except that the phenol raw materials were 765g of 2,6-dimethylphenol, 1142g of 2-tert-butyl-5-methylphenol, and 93g of 2-allylphenol.

[0325] Each analysis result is shown in Table 1.

[0326] (Example 6)

[0327] The operation was carried out in the same manner as in Example 1, except that the phenol raw materials were 503g of 2,6-dimethylphenol, 1128g of 2-tert-butyl-5-methylphenol, and 369g of 2-allylphenol.

[0328] Each analysis result is shown in Table 1.

[0329] (Example 7)

[0330] As in Example 3, oxidative polymerization, copper extraction, liquid-liquid separation, and concentration by a rotary evaporator were performed, and a polymer solution with a polymer concentration of 25 mass% was used as the stock solution for the modification reaction.

[0331] In a 500 mL three-necked flask equipped with a nitrogen gas introduction line at the top of the reactor and a reflux condenser at the vent gas line at the top of the reactor, 200 g of unmodified polyphenylene ether solution and 0.64 g of 4-dimethylaminopyridine were added after purging the reactor with nitrogen. While stirring, 21 mL of triethylamine was added using a syringe. Subsequently, 10.9 mL of methacryloyl chloride was drawn into a syringe and added dropwise into the system at room temperature. One hour after the addition was finished, the flask was heated in an oil bath and stirring was continued at 90°C. Afterward, the mixture was heated further in an oil bath, and the reaction was continued under reflux. Heating was stopped at the stage where 4 hours had elapsed since the start of reflux, and after returning to room temperature, 8 g of methanol was added to stop the reaction. Subsequently, the reaction solution was filtered using a glass filter to obtain a solution from which the byproduct triethylammonium salt had been removed. The above solution was mixed with methanol such that the ratio of methanol to the polymer solution was 10, and the polymer was precipitated. Wet polyphenylene ether was obtained by vacuum filtration using a glass filter. Additionally, the wet polyphenylene ether was washed with an amount of methanol such that the ratio of methanol to wet polyphenylene ether was 2.5. This washing operation was performed three times. Subsequently, the wet polyphenylene ether was maintained at 100°C and 1 mmHg for 8 hours to obtain dry polyphenylene ether. The average number of hydroxyl groups of the polyphenylene ether was measured by the method described above, and it was confirmed that the average number of hydroxyl groups derived from the polyphenylene ether was less than 0.2 per molecule. Also 1 It was determined that the hydroxyl group was modified into a methacrylic group by confirming the olefin-derived proton peak of the methacrylic group through H NMR measurement. The results of each analysis are shown in Table 2.

[0332] (Example 8)

[0333] As in Example 3, oxidative polymerization, copper extraction, liquid-liquid separation, and concentration by a rotary evaporator were performed, and a polymer solution with a polymer concentration of 25 mass% was used as the stock solution for the modification reaction.

[0334] 200 g of unmodified polyphenylene ether solution, 24 g of chloromethyl styrene (a ratio of p-chloromethyl styrene to m-chloromethyl styrene of 50 / 50, manufactured by Tokyo Kasei Kogyo Co., Ltd.), and 1.0 g of tetra-n-butylammonium bromide were added to a 500 mL three-necked flask equipped with a temperature controller, a stirring device, a cooling device, and a dropping funnel. Subsequently, the mixture was stirred to dissolve the solution, and the liquid temperature was raised to 85°C. An aqueous sodium hydroxide solution (4.2 g sodium hydroxide / 104 g water) was added dropwise to the mixture at 1 hour, and stirring was continued at 85°C for 5 hours. Next, the obtained aqueous layer was removed using a separating funnel to obtain a toluene layer containing the polymer (polymer solution). The polymer solution was mixed with methanol in which the ratio of methanol to the polymer solution was 10, and the polymer was precipitated. Wet polyphenylene ether was obtained by vacuum filtration using a glass filter. Additionally, the wet polyphenylene ether was washed with a cleaning solvent (methanol:water = 80:20) in an amount such that the ratio of the cleaning solvent to the wet polyphenylene ether (methanol:water = 80:20) was 2.5. After performing the washing operation with the methanol-water mixed solvent three times, the wet polyphenylene ether was washed with methanol in an amount such that the ratio of methanol to the wet polyphenylene ether was 2.5. After performing the washing operation with methanol twice, the wet polyphenylene ether was maintained at 100°C and 1 mmHg for 8 hours to obtain polyphenylene ether in a dry state. By the method described above, the average number of hydroxyl groups of the polyphenylene ether was measured, and it was confirmed that the average number of hydroxyl groups derived from the polyphenylene ether was less than 0.2 per molecule. Also 1It was determined that the hydroxyl group was modified into a styryl group by performing H NMR measurements and confirming a proton peak of styryl origin at 5 to 7 ppm. The results of each analysis are shown in Table 2.

[0335] (Example 9)

[0336] As in Example 3, oxidative polymerization, copper extraction, liquid-liquid separation, and concentration using a rotary evaporator were performed, and the mixture was maintained at 100°C and 1 mmHg for 2 hours to obtain a dry polyphenylene ether. The dry polyphenylene ether was used as a raw material for a modification reaction.

[0337] 50 g of unmodified polyphenylene ether, 150 g of tetrahydrofuran, 12.6 g of allyl bromide, and 0.8 g of benzyl tributylammonium bromide were added to a 500 mL three-necked flask equipped with a temperature controller, a stirring device, a cooling device, and a dropping funnel, and the mixture was stirred at a liquid temperature of 25 °C. An aqueous sodium hydroxide solution (4.2 g sodium hydroxide / 100 mL water) was added dropwise to the mixture over 60 minutes, and stirring was continued at 25 °C for 12 hours.

[0338] Next, the contents of the flask were neutralized with a 10% hydrochloric acid solution, mixed with methanol having a methanol-to-polymer ratio of 10, and the polymer was precipitated. Wet polyphenylene ether was obtained by vacuum filtration using a glass filter. Additionally, the wet polyphenylene ether was washed with a cleaning solvent (methanol:water = 80:20) in an amount such that the ratio of the cleaning solvent (methanol:water = 80:20) to the wet polyphenylene ether was 2.5. After performing the washing operation with the above methanol-water mixed solvent three times, the wet polyphenylene ether was washed with a methanol in an amount such that the ratio of the methanol to the wet polyphenylene ether was 2.5. After performing the above-described washing operation with methanol twice, the wet polyphenylene ether was subsequently maintained at 100°C and 1 mmHg for 8 hours to obtain dry polyphenylene ether. The average number of hydroxyl groups of the polyphenylene ether was measured by the method described above, and it was confirmed that the average number of hydroxyl groups derived from the polyphenylene ether was less than 0.2 groups / molecule. Also 1 It was determined that the hydroxyl group was modified into an allyl group by confirming a proton peak of allyl origin at 3.5 to 6.5 ppm through H NMR measurement. The results of each analysis are shown in Table 2.

[0339] (Example 10)

[0340] As in Example 5, oxidative polymerization, copper extraction, liquid-liquid separation, and concentration using a rotary evaporator were performed, and the mixture was maintained at 100°C and 1 mmHg for 2 hours to obtain a dry polyphenylene ether. Methacryl modification was performed as in Example 7, except that the dry polyphenylene ether was used as a raw material for the modification reaction. The average number of hydroxyl groups of the polyphenylene ether was measured by the method described above, and it was confirmed that the average number of hydroxyl groups derived from the polyphenylene ether was less than 0.2 / molecule.

[0341] also 1It was determined that the hydroxyl group was modified into a methacrylic group by confirming the olefin-derived proton peak of the methacrylic group through H NMR measurement. The results of each analysis are shown in Table 2.

[0342] (Example 11)

[0343] 20 parts by mass of TAIC (manufactured by Nihon Kasei Co., Ltd.) and 1 part by mass of an organic peroxide (perbutyl P, manufactured by Nichiyu Co., Ltd.) were added to toluene with respect to 79 parts by mass of the polyphenylene ether described in Example 7, and stirred and dissolved to obtain a varnish (solid content concentration 58 mass%). After impregnating L glass cloth (manufactured by Asahi Schwebel, Style: 2116) into this varnish, the excess varnish was scraped off by passing it through a predetermined slit, and the toluene was removed by drying in a drying oven at 105°C for a predetermined time to obtain a prepreg. This prepreg was cut into a predetermined size, and the solid content of the thermosetting composition in the prepreg was calculated by comparing the mass of the prepreg with the mass of a glass cloth of the same size, and it was 52 mass%.

[0344] A copper-clad laminate was obtained by performing a vacuum press with a predetermined number of these prepregs overlapping and additionally overlapping copper foil (manufactured by Furukawa Electric Co., Ltd., thickness 35 μm, GTS-MP foil) on both sides of the overlapped prepregs. In the vacuum press process, first, the pressure was applied at a heating rate of 2°C / min from room temperature, and then, after the temperature reached 200°C, the pressure was applied at 40 kg / cm² while maintaining the temperature at 200°C for 60 minutes.

[0345] Next, a laminate (thickness about 0.5 mm) was obtained by removing the copper foil from the copper-clad laminate by etching.

[0346] Each analysis result is shown in Table 3.

[0347] (Example 12)

[0348] A laminate was obtained in the same manner as in Example 11, except that the polyphenylene ether described in Example 10 was used as the raw material.

[0349] Each analysis result is shown in Table 3.

[0350] (Comparative Example 1)

[0351] A 1.5-liter jacketed reactor equipped with a spurger for introducing oxygen-containing gas at the bottom of the reactor, stirring turbine blades and baffles, and a reflux cooler in the vent gas line at the top of the reactor was fitted with a pre-adjusted mixture of 0.15 g of cuprous oxide and 1.12 g of 47% hydrogen bromide, 0.36 g of N,N'-di-t-butylethylenediamine, 5.31 g of dimethyl-n-butylamine, 1.74 g of di-n-butylamine, and 491.3 g of toluene. Next, while vigorously stirring, air was introduced into the reactor from a spurger at a rate of 1.05 L / min, and oxygen was introduced at the same time, a mixed solution of 98.7 g of 2,6-dimethylphenol, 1.34 g of 2-tert-butyl-5-methylphenol, and 400.0 g of toluene was added to the solution over a period of 60 minutes. The polymerization temperature was controlled by passing a heat medium through a jacket to maintain it at 40°C. 130 minutes after the introduction of air, the air supply was stopped, and after replacing the nitrogen gas inside the reactor, a 20% methanol solution containing 1.03 g of hydroquinone (reagent manufactured by Wako Junyaku Co., Ltd.) was added in small amounts. Thirty minutes after adding the methanol solution of hydroquinone, 1.61 g of ethylenediamine tetraacetate tetrahydrate (reagent manufactured by Tojin Kagaku Genkyusho Co., Ltd.) was added as an aqueous solution of 200 g of water. The solution was heated to 70°C, and copper extraction was performed at 70°C for 2 hours. Subsequently, the solution was separated by settling into an unmodified polyphenylene ether solution (organic phase) and an aqueous phase in which the catalyst metal was transferred. The solution was mixed with methanol at a ratio of 10 to the polymer solution, and the polymer was precipitated. Wet polyphenylene ether was obtained by vacuum filtration using a glass filter. Additionally, the wet polyphenylene ether was washed with an amount of methanol at a ratio of 2.5 to the wet polyphenylene ether. This washing operation was performed three times. Next, the wet polyphenylene ether was maintained at 140°C and 1 mmHg for 120 minutes, and the dry polyphenylene ether was obtained.

[0352] Each measurement was performed on the obtained polyphenylene ether by the method described above. The results of each analysis are shown in Table 1.

[0353] (Comparative Example 2)

[0354] The operation was carried out in the same manner as in Example 1, except that the phenol raw materials were 1973g of 2,6-dimethylphenol and 26.8g of 2-tert-butyl-5-methylphenol.

[0355] Each analysis result is shown in Table 1.

[0356] (Comparative Example 3)

[0357] The operation was carried out in the same manner as in Example 1, except that the phenol raw materials were 1740g of 2,6-dimethylphenol and 260g of 2-tert-butyl-5-methylphenol.

[0358] Each analysis result is shown in Table 1.

[0359] (Comparative Example 4)

[0360] In a 40-liter jacketed polymerization vessel equipped with a spurger for introducing oxygen-containing gas at the bottom of the vessel, stirring turbine blades, and baffles, and equipped with a reflux cooler in the vent gas line at the top of the polymerization vessel, nitrogen gas was blown in at a flow rate of 0.5 L / min, and 4.57 g of cupric oxide, 24.18 g of a 47 mass% aqueous solution of hydrogen bromide, 11.00 g of di-t-butylethylenediamine, 62.72 g of di-n-butylamine, 149.92 g of butyldimethylamine, 20.65 kg of toluene, and 3.12 kg of 2,6-dimethylphenol were added and stirred until a homogeneous solution was formed and the internal temperature of the polymerization vessel reached 25°C. Next, dry air was introduced into the polymerization vessel from the spurger at a rate of 32.8 NL / min, and polymerization was initiated. Dry air was passed through for 140 minutes to obtain a polymerization mixture. In addition, the temperature was controlled to 40°C during polymerization. At the end of polymerization, the polymerization mixture (polymerization solution) was in a homogeneous solution state.

[0361] Dry air circulation was stopped, and 10 kg of a 2.5 mass% aqueous solution of ethylenediamine tetraacetate sodium salt (reagent manufactured by Tojin Kagaku Genkyusho Co., Ltd.) was added to the polymerization mixture. The polymerization mixture was stirred at 70°C for 150 minutes, then left to stand for 20 minutes, and the organic phase and aqueous phase were separated by liquid-liquid separation.

[0362] The separated organic phase yielded a toluene solution containing 13.1 mass% of polyphenylene ether. The solution was placed in a stirred tank equipped with a jacket, and heated by flowing a heat medium at 120°C through the jacket. The generated vapor, which was mainly composed of toluene, was cooled by a condenser to remove the toluene from the system, and the polymer concentration in the stirred tank was concentrated until it reached 30 mass%.

[0363] Next, methanol was mixed such that the ratio of methanol to the polymer solution was 1.0, and the polymer was precipitated. Wet polyphenylene ether was obtained by vacuum filtration using a glass filter. Additionally, the wet polyphenylene ether was washed with an amount of methanol such that the ratio of methanol to wet polyphenylene ether was 2.5. The washing operation was performed three times. Subsequently, the wet polyphenylene ether was maintained at 140°C and 1 mmHg for 120 minutes, and dry polyphenylene ether was obtained.

[0364] Each measurement was performed on the obtained polyphenylene ether by the method described above. The measurement results are shown in Table 1.

[0365] (Comparative Example 5)

[0366] A 40-liter jacketed polymerization vessel equipped with a spurger for introducing oxygen-containing gas at the bottom of the vessel, stirring turbine blades, and baffles, and equipped with a reflux cooler in the vent gas line at the top of the polymerization vessel, was mixed with 4.02 g of cupric oxide, 29.876 g of a 47 mass% aqueous solution of hydrogen bromide, 9.684 g of di-t-butylethylenediamine, 46.88 g of di-n-butylamine, 122.28 g of butyldimethylamine, 17.53 kg of toluene, and 1.5 kg of 2,6-dimethylphenol while blowing nitrogen gas at a flow rate of 0.5 L / min, and stirred until a homogeneous solution was formed and the internal temperature of the polymerization vessel reached 25°C. Next, dry air was introduced into the polymerization vessel from a spurger at a rate of 32.8 NL / min, and at the same time, a solution consisting of 1.62 kg of 2,6-dimethylphenol and 3.12 kg of toluene was added to the polymerization vessel from a plunger pump over a period of 30 minutes. Dry air was passed through for 86 minutes to obtain a polymerization mixture. In addition, the internal temperature was controlled to be 40°C during polymerization. At the end of polymerization, the polymerization mixture (polymerization solution) was in a homogeneous solution state. The operation was carried out in the same manner as in Comparative Example 1.

[0367] Each analysis result is shown in Table 1.

[0368] (Comparative Example 6)

[0369] The phenol raw material was 2 kg of 2,6-dimethylphenol, and the operation was carried out in the same manner as in Example 1, except that the air flow was stopped 117 minutes after the introduction of air began.

[0370] Each analysis result is shown in Table 1.

[0371] (Comparative Example 7)

[0372] 0.88 g of cupric chloride dihydrate, 3.76 g of 35% hydrochloric acid, 33.57 g of N,N,N',N'-tetramethylpropanediamine, 850 g of n-butanol, 1982 g of methanol, and 630 g of 2,6-dimethylphenol were added to a 4.1-liter jacketed reactor equipped with a spurger for introducing oxygen-containing gas at the bottom of the reactor, stirring turbine blades and baffles, and a reflux cooler on the vent gas line at the top of the reactor. The compositional weight ratio of the solvents used was n-butanol:methanol = 30:70. Subsequently, while vigorously stirring, oxygen was introduced into the reactor from the spurger at a rate of 410 mL / min, and at the same time, a heat medium was passed through the jacket to maintain the polymerization temperature at 40°C. The polymerization solution gradually took on the form of a slurry.

[0373] 200 minutes after oxygen was introduced, the oxygen-containing gas was stopped, and a 50% aqueous solution containing 4.56 g of tripotassium ethylenediaminetetraacetate (reagent manufactured by Tojin Kagaku Genkyusho Co., Ltd.) was added to the polymerization mixture, followed by the addition of small amounts of a 20% methanol solution containing 8.52 g of hydroquinone (reagent manufactured by Wako Junyaku Co., Ltd.). The resulting polymerization mixture was transferred to a 4.1-liter jacketed reactor equipped with a reflux condenser on the stirring turbine blades, baffles, and the vent gas line at the top of the reactor, and reacted at 60°C for 3 hours. After the reaction was completed, the mixture was filtered and washed three times with a methanol washing solution (b) in an amount of washing solution (b) such that the mass ratio (b / a) of the polyphenylene ether being washed (a) to the methanol washing solution (b) was 4, thereby obtaining wet polyphenylene ether. Next, dry polyphenylene ether was obtained by vacuum drying at 120°C for 4 hours. The analysis results of the obtained polyphenylene ether are shown in Table 1.

[0374] (Comparative Example 8)

[0375] The operation was carried out in the same manner as in Example 1, except that the phenol raw material was 2 kg of 2-tert-butyl-5-methylphenol.

[0376] Each analysis result is shown in Table 1.

[0377] (Preparation Example 1)

[0378] A 1.5-liter jacketed reactor equipped with a spurger for introducing oxygen-containing gas at the bottom of the reactor, stirring turbine blades and baffles, and a reflux cooler in the vent gas line at the top of the reactor was fitted with a pre-adjusted mixture of 0.092 g of cuprous oxide and 0.69 g of 47% hydrogen bromide, 0.22 g of N,N'-di-t-butylethylenediamine, 3.27 g of dimethyl-n-butylamine, 1.07 g of di-n-butylamine, 714.65 g of toluene, 65.03 g of 2,6-dimethylphenol, and 14.97 g of 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane. Next, while vigorously stirring, air was introduced into the reactor from a spurger at a rate of 0.84 L / min, and at the same time, the polymerization temperature was controlled by passing a heat medium through a jacket to maintain it at 20°C. 150 minutes after the introduction of air, the air flow was stopped, and nitrogen gas was replaced in the reactor. Then, 0.99 g of ethylenediamine tetraacetate tetrahydrate (reagent manufactured by Tojin Kagaku Genkyusho Co., Ltd.) was added to the polymerization mixture as an aqueous solution of 160 g of water. Subsequently, the mixture was heated to 70°C, and copper extraction was carried out at 70°C for 2 hours. Afterward, the mixture was separated by settling into an unmodified polyphenylene ether solution (organic phase) and an aqueous phase in which the catalyst metal had been transferred.

[0379] The obtained unmodified polyphenylene ether was used, and a modified polyphenylene ether was obtained in the same manner as in Example 7.

[0380] Each analysis result is shown in Table 2.

[0381] (Comparative Example 10)

[0382] A laminated board was obtained in the same manner as in Example 11, except that the polyphenylene ether described in Preparation Example 1 was used as a raw material.

[0383] Each analysis result is shown in Table 3.

[0384] (Reference Example 9)

[0385] A pre-adjusted mixture of 0.15 g of cuprous oxide and 1.12 g of 47% hydrogen bromide, 0.36 g of N,N'-di-t-butylethylenediamine, 5.31 g of dimethyl-n-butylamine, 1.74 g of di-n-butylamine, 891.3 g of toluene, 50.0 g of 2,6-dimethylphenol, and 50.0 g of 2,5-dimethylphenol was added to a 1.5-liter jacketed reactor equipped with a spurger for introducing oxygen-containing gas at the bottom of the reactor, stirring turbine blades and baffles, and a reflux cooler on the vent gas line at the top of the reactor. Subsequently, while vigorously stirring, air was introduced into the reactor from the spurger at a rate of 1.05 L / min, and at the same time, a heat medium was passed through the jacket to maintain the polymerization temperature at 40°C. 120 minutes after air was introduced, the entire solution became highly viscous, and a gel formed.

[0386]

[0387]

[0388]

[0389] As shown in Tables 1 and 2, by comparison with the comparative example, it was possible to obtain polyphenylene ethers of various reduced viscosities with increased solvent solubility in methyl ethyl ketone by using the polyphenylene ether of the example. Industrial applicability

[0390] The polyphenylene ether of the present invention has excellent solvent solubility, so it has industrial utility value for use as an electronic material and a modifier.

Claims

Claim 1 A polyphenylene ether characterized by comprising, for a total of 100 mol% of repeating units derived from phenol of Formula (1) and repeating units derived from phenol of Formula (2), 5 to 85 mol% of repeating units derived from phenol of Formula (1) and 15 to 95 mol% of repeating units derived from phenol of Formula (2) (provided, excluding cases where 85 mol% of repeating units derived from phenol of Formula (1) and 15 mol% of repeating units derived from phenol of Formula (2) are included), a reducing viscosity (ηsp / c) measured in a chloroform solution at a concentration of 0.5 g / dL at 30°C of 0.03 to 0.30 dL / g. (In Equation (1), R 11 Each is independently a saturated hydrocarbon group having 1 to 6 carbon atoms that may be substituted, an aryl group having 6 to 12 carbon atoms that may be substituted, or a halogen atom, and R 12 Each is independently a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms that may be substituted, an aryl group having 6 to 12 carbon atoms that may be substituted, or a halogen atom. (In Equation (2), R 22 Each is independently a hydrogen atom, a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms that may be substituted, an aryl group having 6 to 12 carbon atoms that may be substituted, or a halogen atom, and two Rs 22 At least one of them is not a hydrogen atom, and R 21 is a substructure represented by the following equation (3). (Equation (3), R 31 Each is independently a straight-chain alkyl group having 1 to 8 carbon atoms that may be substituted, or two Rs 31 It is a cyclic alkyl structure having 3 to 8 carbon atoms bonded together, and R 32 is each independently an alkylene group having 1 to 8 carbon atoms that may be substituted, b is each independently 0 or 1, and R 33 It is silver, a hydrogen atom, a carbon-1 to carbon-8 alkyl group that may be substituted, or a phenyl group that may be substituted. Claim 2 In claim 1, a polyphenylene ether in which the partial structure represented by the formula (3) is a t-butyl group. Claim 3 Polyphenylene ether according to claim 1 or 2, having an average number of hydroxyl groups of less than 2.5 per molecule. Claim 4 Polyphenylene ether according to claim 1 or 2, having an average number of hydroxyl groups of less than 0.2 per molecule. Claim 5 A polyphenylene ether according to claim 1 or 2, having at least one substructure selected from the group consisting of the following formulas (4), (5), (6) and (7), and having an average number of hydroxyl groups of less than 0.2 / molecule. (In Equation (6), R 6 It is silver, a hydrogen atom, or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and the saturated or unsaturated hydrocarbon may have substituents to the extent that it satisfies the condition of having 1 to 10 carbon atoms. (Equation (7), R 7 Silver is a saturated or unsaturated divalent hydrocarbon group having 1 to 10 carbon atoms, and said saturated or unsaturated divalent hydrocarbon may have substituents to the extent that it satisfies the condition of having 1 to 10 carbon atoms, and R 8 It is a hydrogen atom or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and said saturated or unsaturated hydrocarbon may have substituents to the extent that it satisfies the condition of having 1 to 10 carbon atoms.) Claim 6 A polyphenylene ether according to claim 1 or 2, comprising a repeating unit derived from a monovalent phenol having at least one unsaturated hydrocarbon group at the carbon atom at the ortho position of the carbon atom to which the hydroxyl group of the phenol is bonded. Claim 7 In claim 6, a polyphenylene ether in which the monovalent phenol is 2-allylphenol or 2-methyl-6-allylphenol. Claim 8 A method for producing polyphenylene ether as described in claim 1 or 2, comprising a process of performing oxidative polymerization of the phenol of formula (1) and the phenol of formula (2). Claim 9 A polyphenylene ether solution comprising the polyphenylene ether described in claim 1 or 2 and a ketone-based solvent. Claim 10 A thermosetting composition comprising the polyphenylene ether described in claim 1 or 2. Claim 11 A prepreg comprising the aforementioned and the thermosetting composition described in claim 10. Claim 12 In Clause 11, the prepreg, wherein the above description is glass cloth. Claim 13 A laminate comprising a cured prepreg described in paragraph 11 and a metal foil.

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