Polyphenylene ether, resin composition, resin film, prepreg, and metal-clad laminate

Abstract

To provide polyphenylene ether which is excellent in electric characteristics and heat resistance, a resin composition using the same, and a method for producing the same, and to provide a resin film, a prepreg, and a metal-clad laminate, which are formed using the polyphenylene ether resin composition.SOLUTION: Polyphenylene ether has reduction viscosity (ηsp / c) measured by a chloroform solution with a concentration of 0.5 g / dL at 30°C of 0.13-0.30 dL / g, and has the number of OH groups of 100-330 μmol / g, the number of OH groups per one molecule of 0.3-3.0 pieces / molecule, and a ratio of an integral value of a peak appearing at 7.6-8.3 ppm to an integral value of a peak derived from 1,3,5-trimetoxybenzene in a 1H-NMR measurement result measured by adding 1 mass% of 1,3,5-trimetoxybenzene thereto is 0.1 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to polyphenylene ether, resin compositions, resin films, prepregs, and metal-clad laminates. [Background technology]

[0002] Polyphenylene ether (hereinafter also referred to as "PPE") is widely used as a material for products and components in the electrical and electronic, automotive, and food and packaging fields, as well as in various other industrial materials, due to its excellent high-frequency properties, flame retardancy, and heat resistance. In particular, in recent years, its low dielectric properties and heat resistance have led to its application as a modifier in various applications, including electrical and electronic applications such as substrate materials.

[0003] However, generally speaking, high molecular weight polyphenylene ethers with repeating units derived from monovalent phenols, such as 2,6-dimethylphenol, are soluble in highly toxic solvents such as chloroform, but are poorly soluble at high concentrations in aromatic solvents such as toluene, which are known as good solvents, at room temperature, and are insoluble in ketone solvents such as methyl ethyl ketone. Therefore, when used as a wiring board material, for example, handling with resin varnish solutions such as toluene or methyl ethyl ketone becomes difficult.

[0004] Patent Document 1 discloses a resin composition comprising a low molecular weight polyphenylene ether having a polyphenylene ether moiety within its molecular structure and having at least one p-ethenylbenzyl group or m-ethenylbenzyl group at the end of this molecular structure, and a crosslinking curing agent. Furthermore, Patent Document 2 discloses a curable composition comprising a bifunctional polyphenylene ether having methacrylic groups at its molecular termini, an unsaturated polyester resin or vinyl ester resin, a reactive liquid monomer, and a compatibilizer. In addition, Patent Document 3 discloses a resin composition containing a low-molecular-weight polyphenylene ether component composed of a polyfunctional phenol having a predetermined skeleton obtained by a redistribution reaction of a high-molecular-weight polyphenylene ether and a polyfunctional phenol, a crosslinking agent, and an organic peroxide.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] As described above, Patent Documents 1 to 3 disclose a method for producing a resin composition containing a low-molecular-weight polyphenylene ether for improving the solvent solubility of polyphenylene ether, a crosslinking agent, etc. However, there is a problem that the dielectric properties and heat resistance derived from the polyphenylene ether skeleton may become insufficient due to the low molecular weight of the polyphenylene ether. In addition, in the low-molecular-weight polyphenylene ether obtained by the redistribution reaction of a high-molecular-weight polyphenylene ether and a polyfunctional phenol as described in Patent Document 3, an organic peroxide generally used in the redistribution reaction is contained, and the residual organic peroxide in the product may affect the dielectric properties of the substrate.

[0007] The present invention has been made in view of the above problems, and an object thereof is to provide a polyphenylene ether excellent in electrical properties and heat resistance, a resin composition using the same, and a method for producing the same. Another object is to provide a resin film, a prepreg, and a metal-clad laminate formed using the polyphenylene ether resin composition.

Means for Solving the Problems

[0008] In other words, the present invention is as follows: [1] The reduced viscosity (ηsp / c) measured with a chloroform solution at a concentration of 0.5 g / dL at 30°C was 0.13 to 0.30 dL / g. It has 100-330 μmol / g of OH groups, and the number of OH groups per molecule is 0.3-3.0 / molecule. Measurement was performed after adding 1% by mass of 1,3,5-trimethoxybenzene. 1 A polyphenylene ether characterized in that, in the 1H-NMR measurement results, the ratio of the integrated value of the peak appearing at 7.6-8.3 ppm to the integrated value of the peak derived from 1,3,5-trimethoxybenzene is 0.1 or less. [2] The polyphenylene ether according to [1], comprising a repeating unit derived from phenol of formula (1) below and a repeating unit derived from phenol of formula (2) below. [ka] (In formula (1), R 11 Each of these is independently a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted, an aryl group having 6 to 12 carbon atoms which may be substituted, or a halogen atom, and R 12 Each of these is independently a hydrogen atom, an optionally substituted C1-C6 hydrocarbon group, an optionally substituted C6-C12 aryl group, or a halogen atom. [ka] {In formula (2), R 22 Each of these is independently a hydrogen atom, an optionally substituted saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, or a halogen atom, and two R 22 Both are not hydrogen atoms, R 21 This is a substructure represented by the following equation (3). [ka] (In formula (3), R 31 is each independently a linear alkyl group having 1 to 8 carbon atoms which may be substituted, or a cyclic alkyl structure having 1 to 8 carbon atoms to which two R 31 are bonded, R 32 is each independently an alkylene group having 1 to 8 carbon atoms which may be substituted, b is each independently 0 or 1, and R 33 is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms which may be substituted, or a phenyl group which may be substituted.)} [3] Based on 100 mol% in total of the repeating unit derived from the phenol of the formula (1) and the repeating unit derived from the phenol of the formula (2), the repeating unit derived from the phenol of the formula (1) is more than 85 mol% and 95 mol% or less, and the repeating unit derived from the phenol of the formula (2) is 5 mol% or more and less than 15 mol%, the polyphenylene ether according to [2]. [4] The polyphenylene ether according to any one of [1] to [3], comprising a structural unit derived from the phenol of the following formula (4). [Chemical formula] (In formula (4), X is an a-valent arbitrary linking group, a is an integer of 2 to 6, R 4 is either a linear alkyl group having 1 to 8 carbon atoms or a partial structure represented by the following formula (3), and is bonded to at least one of the carbon atoms at the 2-position or the 6-position with the carbon atom of the benzene ring to which -O- is bonded as the 1-position, and k is each independently an integer of 1 to 4.) [Chemical formula] (In formula (3), R 31 is each independently a linear alkyl group having 1 to 8 carbon atoms which may be substituted, or a cyclic alkyl structure having 1 to 8 carbon atoms to which two R 31 are bonded, R 32Each is independently an alkylene group having 1 to 8 carbon atoms, which may be substituted, and each is independently 0 or 1, R 33 (This is a hydrogen atom, an optionally substituted C1-C8 alkyl group, or an optionally substituted phenyl group.) [5] A resin composition comprising a polyphenylene ether, a crosslinking agent, and an organic peroxide as described in any of [1] to [4]. [6] The resin composition according to [5], wherein the crosslinking agent has an average of two or more carbon-carbon unsaturated double bonds in one molecule, and the number average molecular weight of the crosslinking agent is 4,000 or less. [7] The resin composition according to [5] or [6], wherein the mass ratio of the polyphenylene ether to the crosslinking agent is 25:75 to 95:5. [8] The resin composition according to any one of [5] to [7], wherein the 1-minute half-life temperature of the organic peroxide is 155°C to 185°C. [9] The resin composition according to any one of [5] to [8], wherein the content of the organic peroxide is 0.05 parts by mass to 10 parts by mass based on 100 parts by mass of the total mass of the polyphenylene ether and the crosslinking agent.

[10] The resin composition according to any one of [5] to [9], wherein the resin composition further comprises a thermoplastic resin, the thermoplastic resin being at least one selected from the group consisting of block copolymers of vinyl aromatic compounds and olefin-based alkene compounds and their hydrogenated products, and homopolymers of vinyl aromatic compounds, and the content of units derived from the vinyl aromatic compound in the block copolymer or its hydrogenated product is 20% by mass or more.

[11] The resin composition according to

[10] , wherein the weight-average molecular weight of the thermoplastic resin is 10,000 to 300,000.

[12] The resin composition according to

[10] or

[11] , wherein the content of the thermoplastic resin is 2 to 20 parts by mass, based on 100 parts by mass of the total mass of the polyphenylene ether and the crosslinking agent.

[13] The resin composition according to any one of [5] to

[12] , further comprising a flame retardant, wherein the flame retardant is immiscible with other components in the resin composition after curing.

[14] A resin film comprising the resin composition described in any of [5] to

[13] .

[15] A prepreg that is a composite of a substrate and a resin composition described in any of [5] to

[13] .

[16] The prepreg according to

[15] , wherein the substrate is glass cloth.

[17]

[14] A metal-clad laminate which is a laminate of a cured resin film described in

[14] and a metal foil.

[18] A metal-clad laminate which is a laminate of a cured prepreg described in

[15] or

[16] and a metal foil. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a polyphenylene ether with excellent electrical properties and heat resistance, and a method for producing a resin composition using the same. Furthermore, it is possible to provide an electronic circuit board material, a resin film, a prepreg, and a metal-clad laminate formed using the polyphenylene ether resin composition. [Modes for carrying out the invention]

[0010] The following describes in detail embodiments for carrying out the present invention (hereinafter referred to as "this embodiment"). This embodiment is an example for illustrating the present invention, and the present invention is not limited to this embodiment. The present invention can be appropriately modified and implemented within the scope of its gist.

[0011] In this embodiment, polyphenylene ether in which some or all of the hydroxyl groups contained in the polyphenylene ether have been modified may be simply referred to as "polyphenylene ether." Therefore, when the term "polyphenylene ether" is used, it includes both unmodified polyphenylene ether and modified polyphenylene ether, unless otherwise inconsistent.

[0012] In this specification, A(numerical value) to B(numerical value) means A or greater and B or less. In this specification, substituents refer to, for example, saturated or unsaturated hydrocarbon groups having 1 to 10 carbon atoms, aryl groups having 6 to 10 carbon atoms, halogen atoms, etc.

[0013] <Polyphenylene ether> The polyphenylene ether of this embodiment has a reduced viscosity (ηsp / c) of 0.13 to 0.30 dL / g, preferably 0.14 to 0.28 dL / g, and more preferably 0.15 to 0.25 dL / g, measured in a chloroform solution with a concentration of 0.5 g / dL at 30°C. A reduced viscosity (ηsp / c) of 0.13 dL / g or higher, measured with a 0.5 g / dL chloroform solution at 30°C, indicates high heat resistance and excellent dielectric properties derived from the polyphenylene ether structure, while a reduced viscosity of 0.30 dL / g or lower ensures solubility in solvents such as toluene and methyl ethyl ketone. The reduced viscosity can be measured by the method described in the examples below.

[0014] The polyphenylene ether of this embodiment has 100 to 330 μmol / g of OH groups, preferably 100 to 310 μmol / g, and more preferably 100 to 300 μmol / g. A OH group count of 100 μmol / g or more improves adhesion to copper foil, while a count of 330 μmol / g or less improves the heat resistance and dielectric properties of the substrate. The number of OH groups in polyphenylene ether can be measured by the method described in the examples below.

[0015] The polyphenylene ether of this embodiment has 0.3 to 3.0 OH groups per molecule, preferably 0.8 to 2.8 OH groups per molecule, and more preferably 1.0 to 2.5 OH groups per molecule. Having 0.3 or more OH groups per molecule improves adhesion to copper foil, while having 3.0 or fewer OH groups per molecule improves the heat resistance and dielectric properties of the substrate, ensuring the manufacturing stability of polyphenylene ether. The number of OH groups per molecule of polyphenylene ether can be measured by the method described in the examples below.

[0016] In this embodiment, the polyphenylene ether was measured by adding 1% by mass of 1,3,5-trimethoxybenzene to the polyphenylene ether. 1 In the 1H-NMR measurement results, the ratio of the integrated value of the peak appearing at 7.6 to 8.3 ppm to the integrated value of the peak derived from 1,3,5-trimethoxybenzene is 0.1 or less. This ratio is preferably 0.08 or less, more preferably 0.06 or less, and even more preferably 0.05 or less. The lower limit of this ratio is not particularly limited, but may be 0.

[0017] 1 The peak appearing at 7.6–8.3 ppm in the H-NMR measurement is thought to be a peak originating from peroxides, and a small cumulative value of these peaks indicates that the polyphenylene ether does not contain a large amount of peroxides. In this embodiment, the polyphenylene ether has a cumulative value of 0.1 or less, resulting in good dielectric properties of the substrate. Polyphenylene ether 1 1H-NMR can be measured by the method described in the examples below.

[0018] The polyphenylene ether of this embodiment contains at least a repeating unit derived from the phenol of formula (1) and a repeating unit derived from the phenol of formula (2), and may consist only of the repeating unit derived from the phenol of formula (1) and the repeating unit derived from the phenol of formula (2). [ka] (In formula (1), R 11 Each of these is independently a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted, an aryl group having 6 to 12 carbon atoms which may be substituted, or a halogen atom, and R 12 Each of these is independently a hydrogen atom, an optionally substituted C1-C6 hydrocarbon group, an optionally substituted C6-C12 aryl group, or a halogen atom. [ka] {In formula (2), R 22 Each of these is independently a hydrogen atom, an optionally substituted saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, or a halogen atom, and two R 22 Both are not hydrogen atoms, R 21 This is a substructure represented by the following equation (3). [ka] (In formula (3), R 31 Each of these is independently a linear alkyl group having 1 to 8 carbon atoms, which may be substituted, or two R 31 It is a cyclic alkyl structure with 1 to 8 carbon atoms bonded together, R 32 Each is independently an alkylene group having 1 to 8 carbon atoms, which may be substituted, and each is independently 0 or 1, R 33 (This is one of the following: a hydrogen atom, an optionally substituted C1-C8 alkyl group, or an optionally substituted phenyl group.)

[0019] In the above equation (1), R 11Each of these is preferably an independently 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 R 11 It is preferable that both have the same structure.

[0020] In the above equation (1), R 12 Each of these is preferably 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 R 12 These are preferably different, and more preferably one is a hydrogen atom and the other is a hydrocarbon group having 1 to 6 carbon atoms (preferably a methyl group).

[0021] In equation (2) above, R 22 Each of these is preferably independently a hydrogen atom, a saturated or unsaturated hydrocarbon group having 1 to 15 carbon atoms, or an aryl group having 6 to 12 carbon atoms that may be substituted with an alkyl group having 1 to 6 carbon atoms; more preferably a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms that may be substituted with an alkyl group having 1 to 6 carbon atoms; and even more preferably a hydrogen atom or a methyl group. In formula (2), the two R 22 These are preferably different, and more preferably one is a hydrogen atom and the other is a hydrocarbon group having 1 to 6 carbon atoms (preferably a methyl group).

[0022] The substructure represented by formula (3) above 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 its terminal, more preferably a tert-butyl group or a cyclohexyl group, and even more preferably a tert-butyl group.

[0023] In this embodiment, the structure of polyphenylene ether can be identified by analyzing it using techniques such as NMR and mass spectrometry. A specific method for identifying the structure of polyphenylene ether involves performing field desorption mass spectrometry (FD-MS), which is known to be less prone to fragmentation, and estimating the repeating units based on the spacing of the detected ions. Furthermore, a method for estimating the structure of polyphenylene ether can be proposed by combining electron ionization (EI) peak analysis of fragment ions with structural analysis by NMR.

[0024] The polyphenylene ether of this embodiment preferably contains 85 to 95 mol% of repeating units derived from phenol of formula (1) and 5 to 15 mol% of repeating units derived from phenol of formula (2), based on a total of 100 mol% of repeating units derived from phenol of formula (1) and repeating units derived from phenol of formula (2). The polyphenylene ether of this embodiment contains repeating units derived from phenol of formula (1) and repeating units derived from phenol of formula (2) in the above proportions, thereby improving the heat resistance and dielectric properties of the substrate. The polyphenylene ether of this embodiment more preferably contains 85 mol% or more and 95 mol% or less of repeating units derived from the phenol of formula (1), and 5 mol% or more and less than 15 mol% of repeating units derived from the phenol of formula (2), and even more preferably contains 85 mol% or more and 90 mol% or less of repeating units derived from the phenol of formula (1), and 10 mol% or more and less than 15 mol% of repeating units derived from the phenol of formula (2).

[0025] Since the phenol in formula (1) does not have an unsubstituted ortho position (i.e., hydrogen atoms are not bonded to the two ortho carbon atoms of the carbon atom to which the hydroxyl group is bonded), it can react with other phenolic monomers only at the phenolic hydroxyl group and the para carbon atom. Therefore, the repeating units derived from formula (1) include repeating units having the structure of formula (5) below. [ka] (In formula (5), R 11 and R 12 This is the same as equation (1).

[0026] The phenol of formula (2) can react with another phenolic monomer at either the ortho or para position of the phenol, in addition to the phenolic hydroxyl group. Therefore, repeating units derived from the phenol of formula (2) have the structures of formulas (6) and (7) below, or combinations thereof. [ka] [ka] (R in equations (6) and (7)) 21 , R 22 This is the same as equation (2).

[0027] The polyphenylene ether of this embodiment may contain structural units derived from phenol of the following formula (4). [ka] (In equation (4), X is any a-valent linking group, a is an integer from 2 to 6, and R 4 k is either a linear alkyl group having 1 to 8 carbon atoms or a substructure represented by formula (3), and is bonded to at least one of the carbon atoms at positions 2 or 6 of the benzene ring to which -O- is bonded, with the carbon atom at position 1 being the bonded atom. k is an integer from 1 to 4, independently of the other two.

[0028] In the above equation (4), R 4 Each of these is independently one of a linear alkyl group having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, or an n-propyl group, and one of the substructures represented by formula (3) above, and it is preferable that they are a methyl group or the structure of formula (3) above. Each of the a substructures may be the same or different. In particular, from the viewpoint of obtaining a polyphenylene ether with even better solubility in the solvent and an even higher glass transition temperature after curing, it is preferable that each of the a substructures is the same.

[0029] In the above formula (4), k is an integer between 1 and 4, preferably between 2 and 4.

[0030] R 4 The R bonded to the benzene ring is positioned at position 2 and / or 6, with the carbon atom to which the -O- bond is attached being at position 1. 3 When is a linear alkyl group having 1 to 8 carbon atoms, it is preferable that it is bonded to both the 2nd and 6th positions, and R bonded to the 2nd and / or 6th positions 4 If the substructure is represented by formula (3), it is preferable that it is bonded to only one of either the 2nd or 6th position.

[0031] The polyphenylene ether of this embodiment may also include repeating units derived from formula (4) above, and repeating units derived from phenol of formula (1) above and / or repeating units derived from phenol of formula (2) above. In this case, R of formula (2) above 21 and R in equation (4) above 4 If both are substructures (functional groups) represented by formula (3) (i.e., both the phenol compound represented by formula (2) and the phenol compound represented by formula (4) are substituted with the substructures (functional groups) represented by formula (3)), the structures of each substructure (functional group) represented by formula (3) may be the same or different.

[0032] In formula (4) above, X is any a-valent linking group and is not particularly limited, but examples include hydrocarbon groups such as chain hydrocarbons and cyclic hydrocarbons; hydrocarbon groups containing one or more atoms selected from nitrogen, phosphorus, silicon, and oxygen; atoms such as nitrogen, phosphorus, and silicon; or groups combining these. X may be a linking group excluding single bonds. X may be a linking group that links a substructures together.

[0033] As for X above, R is connected via a single bond or an ester bond, etc. 4 R 4 R 4 Examples include α-valent heterocyclic skeletons bonded to a benzene ring.

[0034] Here, the alkyl skeleton is not particularly limited, but examples include a chain hydrocarbon with 2 to 6 carbon atoms and at least a branched chain (e.g., a chain saturated hydrocarbon) in which the branched ends are directly bonded to the benzene ring of the substructure (it is sufficient that a benzene ring is bonded to a branched end, and there may be branched ends that are not bonded to a benzene ring). Also, the aryl skeleton is not particularly limited, but examples include a benzene ring, a mesitylene group, or a 2-hydroxy-5-methyl-1,3-phenylene group bonded via a single bond or an alkyl chain, R 4 Examples include skeletons that bond to a benzene ring to which R is attached. Furthermore, there are no particular limitations on the heterocyclic skeleton, but for example, a triazine ring is bonded via a single bond or alkyl chain, 4 Examples include skeletons that bond to the benzene ring to which the compound is attached.

[0035] In the above formula (4), a is an integer between 2 and 6, preferably between 2 and 4.

[0036] If the phenol of formula (4) does not have an unsubstituted ortho position, the structural unit derived from the phenol of formula (4) has the structure of formula (8) below, and if the phenol of formula (4) has an unsubstituted ortho position, the structural unit derived from the phenol of formula (4) has the structure of formula (8) below, the structure of formula (9) below, or a combination thereof. [ka] [ka] (R in equations (8) and (9)) 4 This is the same as equation (4).

[0037] The polyphenylene ether in this embodiment may be a modified polyphenylene ether in which the hydroxyl groups contained in the polyphenylene ether are modified into functional groups (for example, functional groups containing unsaturated carbon bonds).

[0038] The polyphenylene ether in this embodiment may have at least one substructure selected from the group consisting of the following formulas (10), (11), (12), and (13). [ka] [ka] [ka] (In formula (12), R 6 R is a hydrogen atom or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and the above saturated or unsaturated hydrocarbon is R 6 The substituents may be present within the range of 1 to 10 total carbon atoms. [ka] (In formula (13), R 7 R is a saturated or unsaturated divalent hydrocarbon group having 1 to 10 carbon atoms, and the above saturated or unsaturated divalent hydrocarbon is R7 The substituents may be within the range of 1 to 10 carbon atoms, R 8 R is a hydrogen atom or a saturated or unsaturated hydrocarbon group having 1 to 10 carbon atoms, and the saturated or unsaturated hydrocarbon is R 8 The substituents may differ in total carbon number by 1 to 10.

[0039] Furthermore, at least one substructure selected from the group consisting of formulas (10), (11), (12), and (13) above may be directly bonded to the hydroxyl group contained in the polyphenylene ether.

[0040] The polyphenylene ether in this embodiment may include a monovalent phenol having at least one unsaturated hydrocarbon group on the ortho carbon atom of the carbon atom to which the hydroxyl group of phenol is bonded. The monovalent phenol having at least one unsaturated hydrocarbon group on the ortho carbon atom of the carbon atom to which the hydroxyl group of phenol is bonded refers to a monovalent phenol different from the phenol of formula (1) or the phenol of formula (2).

[0041] The unsaturated hydrocarbon group is preferably an unsaturated hydrocarbon group having 3 to 10 carbon atoms, and preferably an unsaturated hydrocarbon group having 3 to 5 carbon atoms. Examples of such unsaturated hydrocarbon groups include alkenyl groups (e.g., vinyl group, allyl group, etc.) and alkynyl groups (e.g., ethynyl group, 1-propynyl, 2-propynyl, etc.).

[0042] The above unsaturated hydrocarbon may have substituents to the extent that it satisfies the condition of having 3 to 10 carbon atoms.

[0043] The introduction rate of monovalent phenol having at least one unsaturated hydrocarbon group on the ortho carbon atom of the carbon atom to which the hydroxyl group of phenol is bonded may be adjusted as appropriate to control the number of curable functional groups. However, the amount of monovalent phenol having at least one unsaturated hydrocarbon group on the ortho carbon atom 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%, relative to the total amount of phenol of formula (1) and monovalent phenol having at least one unsaturated hydrocarbon group on the ortho carbon atom of the oxygen atom of phenol.

[0044] In the polyphenylene ether of this embodiment, the molar ratio of the repeating units derived from the phenol of formula (1) and the monovalent phenol having at least one unsaturated hydrocarbon group on the ortho carbon atom to which the hydroxyl group of the phenol is bonded, to the total of the repeating units derived from the phenol of formula (1) and the monovalent phenol having at least one unsaturated hydrocarbon group on the ortho 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%.

[0045] <Method for producing polyphenylene ether> The polyphenylene ether of this embodiment can be obtained, for example, by a method that includes at least a step of oxidative polymerization of a monovalent phenol compound represented by formula (1) and formula (2), or oxidative polymerization of a monovalent and polyvalent phenol compound represented by formula (1) and formula (4). The step of oxidative polymerization preferably involves oxidative polymerization of a raw material containing at least the phenol of formula (1) and the phenol of formula (2), or the phenol of formula (1) and the phenol of formula (4).

[0046] Examples of monovalent phenol compounds represented by the above formula (1) include 2,6-dimethylphenol, 2-methyl-6-ethylphenol, 2,6-diethylphenol, 2-ethyl-6-n-propylphenol, 2-methyl-6-chlorophenol, 2-methyl-6-bromophenol, 2-methyl-6-n-propylphenol, 2-ethyl-6-bromophenol, 2-methyl-6-n-butylphenol, 2,6-di-n-propylphenol, 2-ethyl-6-chlorophenol, 2-methyl-6-phenylphenol, 2,6-diphenylphenol, 2-methyl-6-tolylphenol, 2,6-ditolylphenol, 2,3,6-trimethylphenol, 2,3-diethyl-6-n-propylphenol, 2,3,6-tributylphenol, 2,6-di-n-butyl-3-methylphenol, 2,6-dimethyl-3-n-butylphenol, and 2,6-dimethyl-3-t-butylphenol. In particular, 2,6-dimethylphenol, 2,3,6-trimethylphenol, and 2,6-diphenylphenol are preferred because they are inexpensive and readily available. The monovalent phenol compound represented by formula (1) above may be used individually or in combination of multiple types.

[0047] Examples of monovalent phenol compounds represented by formula (2) above include 2-isopropyl-5-methylphenol, 2-cyclohexyl-5-methylphenol, 2-tert-butyl-5-methylphenol, and 2-isobutyl-5-methylphenol. From the viewpoint of suppressing multi-branching and gelation, 2-t-butyl-5-methylphenol and 2-cyclohexyl-5-methylphenol, which have bulky substituents, are more preferred. The monovalent phenol compound represented by formula (2) above may be used individually or in combination of multiple types.

[0048] Among the polyvalent phenol compounds represented by the above formula (4), examples of phenol compounds having two phenol units in the molecule include 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4,4'-methylenebis(2,6-dimethylphenol), bis(4-hydroxy-3-methylphenyl)sulfide, bis(4-hydroxy-3,5-dimethylphenyl)sulfone, α,α'-bis(4-hydroxy-3,5-dimethylphenyl)-1,4-diisopropylbenzene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, and 1,1-bis(2-methyl-4-hydroxy-5-t-butylphenyl)butane. In particular, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane and 1,1-bis(2-methyl-4-hydroxy-5-t-butylphenyl)butane are preferred because they are inexpensive and readily available.

[0049] Furthermore, among the polyvalent phenol compounds represented by the above formula (4), phenol compounds having three or more phenol units in the molecule include, for example, 4,4'-[(3-hydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(3-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 4,4'-[(4-hydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(4-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), and 4,4'-[(2 [(4-hydroxy-3-methoxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(4-hydroxy-3-ethoxyphenyl)methylene]bis(2,3,6-trimethylethylphenol), 4,4'-[(3,4-dihydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(3,4-dihydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 2,2'-[(4-hydroxyphenyl)methylene]bis(3,5,6-trimethylphenol), 4,4'-[4-(4-hydroxyphenyl)methylene]bis(3,5,6-trimethylphenol] [phenyl)cyclohexylidene]bis(2,6-dimethylphenol), 4,4'-[(2-hydroxyphenyl)methylene]-bis(2,3,6-trimethylphenol), 4,4'-[1-[4-[1-(4-hydroxy-3,5-dimethylphenyl)-1-methylethyl]phenyl]ethylidene]bis(2,6-dimethylphenol), 4,4'-[1-[4-[1-(4-hydroxy-3-fluorophenyl)-1-methylethyl]phenyl]ethylidene]bis(2,6-dimethylphenol), 2,6-bis[(4-hydroxy-3,5-dimethylethyl] [(4-hydroxyphenyl)ethyl]-4-methylphenol, 2,6-bis[(4-hydroxy-2,3,6-trimethylphenyl)methyl]-4-methylphenol, 2,6-bis[(4-hydroxy-3,5,6-trimethylphenyl)methyl]-4-ethylphenol, 2,4-bis[(4-hydroxy-3-methylphenyl)methyl]-6-methylphenol, 2,6-bis[(4-hydroxy-3-methylphenyl)methyl]-4-methylphenol, 2,4-bis[(4-hydroxy-3-cyclohexylphenyl)methyl]-6-methylphenol, 2,4-bis[(4-hydroxy-3-methylphenyl)methyl]-6-cyclohexylphenol, 2,4-bis[(2-hydroxy-5-methylphenyl)methyl]-6-cyclohexylphenol, 2,4-bis[(4-hydroxy-2,3,6-trimethylphenyl)methyl]-6-cyclohexylphenol, 3,6-bis[(4-hydroxy-3,5-dimethylphenyl)methyl]-1,2-benzenediol, 4,6-bis[(4-hydroxy-3,5-dimethylphenyl)methyl]-1,3-benzenediol, 2,4,6 -Tris[(4-hydroxy-3,5-dimethylphenyl)methyl]-1,3-benzenediol, 2,4,6-Tris[(2-hydroxy-3,5-dimethylphenyl)methyl]-1,3-benzenediol, 2,2'-Methylenebis[6-[(4 / 2-hydroxy-2,5 / 3,6-dimethylphenyl)methyl]-4-methylphenol], 2,2'-Methylenebis[6-[(4-hydroxy-3,5-dimethylphenyl)methyl]-4-methylphenol], 2,2'-Methylenebis[6-[(4 / 2-hydroxy-2,3,5 / 3 [4,6-trimethylphenyl)methyl]-4-methylphenol], 2,2'-methylenebis[6-[(4-hydroxy-2,3,5-trimethylphenyl)methyl]-4-methylphenol], 4,4'-methylenebis[2-[(2,4-dihydroxyphenyl)methyl]-6-methylphenol], 4,4'-methylenebis[2-[(2,4-dihydroxyphenyl)methyl]-3,6-dimethylphenol], 4,4'-methylenebis[2-[(2,4-dihydroxy-3-methylphenyl)methyl]-3,6-dimethylphenol 4,4'-methylenebis[2-[(2,3,4-trihydroxyphenyl)methyl]-3,6-dimethylphenol], 6,6'-methylenebis[4-[(4-hydroxy-3,5-dimethylphenyl)methyl]-1,2,3-benzenetriol], 4,4'-cyclohexyllidenbis[2-cyclohexyl-6-[(2-hydroxy-5-methylphenyl)methyl]phenol], 4,4'-cyclohexyllidenbis[2-cyclohexyl-6-[(4-hydroxy-3,5-dimethylphenyl)methyl]phenol], 4,Examples include 4'-cyclohexyllidenebis[2-cyclohexyl-6-[(4-hydroxy-2-methyl-5-cyclohexylphenyl)methyl]phenol], 4,4'-cyclohexyllidenebis[2-cyclohexyl-6-[(2,3,4-trihydroxyphenyl)methyl]phenol], 4,4',4'',4'''-(1,2-ethanediylidene)tetrakis(2,6-dimethylphenol), 4,4',4'',4'''-(1,4-phenylenedimethylidene)tetrakis(2,6-dimethylphenol), and 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane. Among these, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane is particularly preferred due to its low cost and easy availability. The polyvalent phenol compound represented by formula (4) above may be used individually or in combination of multiple types.

[0050] The number of phenolic hydroxyl groups in the polyvalent phenol compound represented by formula (4) above is not particularly limited as long as it is between 2 and 6, but from the viewpoint of making it easier to control the thermosetting rate, it is preferably between 2 and 4.

[0051] The above oxidative polymerization process is obtained, for example, by oxidative polymerization of a raw material containing, 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 carbon atom of the carbon atom to which the hydroxyl group of the phenol is bonded.

[0052] A monovalent phenol having at least one unsaturated hydrocarbon group on the ortho carbon atom to which the hydroxyl group of the phenol is bonded is preferably a monovalent phenol in which at least one (preferably one) unsaturated hydrocarbon group is bonded to the ortho carbon atom, and hydrogen atoms are bonded to the meta and para carbon atoms. More preferably, it is 2-allylphenol, 2-allyl-6-methylphenol, and even more preferably 2-allylphenol.

[0053] The monovalent phenol having at least one unsaturated hydrocarbon group on the ortho carbon atom of the carbon atom to which the hydroxyl group of the phenol is bonded may be used alone or in combination of multiple types.

[0054] Typically, oxidative polymerization of phenols with a hydrogen atom in the ortho position (e.g., 2-methylphenol, 2,5-dimethylphenol, 2-phenylphenol) can form ether bonds even at the ortho position. This makes it difficult to control the bonding position of the phenol compound during oxidative polymerization, resulting in high molecular weight polymers with an average of 3.5 or more hydroxyl groups per molecule, which are polymerized in a branched manner, ultimately generating a gel component that is insoluble in solvents.

[0055] On the other hand, when the phenol represented by formula (2) has a bulky substituent at one ortho position, it becomes possible to control the bonding position of the phenol compound during oxidative polymerization, even though there is a hydrogen atom at the opposite ortho position, and it is possible to obtain a polyphenylene ether with an average of less than 3.0 hydroxyl groups per molecule.

[0056] Furthermore, when the phenol represented by formula (2) has a bulky substituent at one of its ortho positions, even when a monovalent phenol having a non-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 is used as the third component, gelation does not occur, and a polyphenylene ether with an average of less than 3.0 hydroxyl groups per molecule can be obtained.

[0057] In this embodiment, the molecular weight of the polyphenylene ether can be adjusted, for example, by the molar ratio of the structure of formula (2) to the total of the structures of formula (1) and formula (2), or by the molar ratio of the structure of formula (4) to the total of the structures of formula (1) and formula (4). That is, if the molar ratio of the structure of formula (2) or formula (4) is high, the molecular weight (reduced viscosity) can be lowered, and if the molar ratio of the structure of formula (2) or formula (4) is low, the molecular weight (reduced viscosity) can be adjusted to be higher.

[0058] (Oxidative polymerization process) In the method for producing polyphenylene ether, an aromatic solvent, which is a good solvent for polyphenylene ether, can be used as the polymerization solvent in the oxidative polymerization step.

[0059] Here, a good solvent for polyphenylene ether is a solvent that can dissolve polyphenylene ether. Examples of such solvents include aromatic hydrocarbons such as benzene, toluene, xylene (including o-, m-, and p- isomers), and ethylbenzene, as well as halogenated hydrocarbons such as chlorobenzene and dichlorobenzene; and nitro compounds such as nitrobenzene.

[0060] As the polymerization catalyst used in this embodiment, any known catalyst system that can be used in the production of polyphenylene ethers can be used. Commonly known catalyst systems consist of a transition metal ion having redox activity and an amine compound that can form a complex with the transition metal ion. Examples include catalyst systems consisting of a copper compound and an amine compound, a catalyst system consisting of a manganese compound and an amine compound, a catalyst system consisting of a cobalt compound and an amine compound, and so on. Since the polymerization reaction proceeds efficiently under slightly alkaline conditions, a small amount of alkali or further amine compounds may be added.

[0061] The polymerization catalyst preferred in this embodiment is a catalyst comprising a copper compound, a halogen compound, and an amine compound as catalyst components, and more preferably a catalyst containing a diamine compound represented by the following formula (14) as the amine compound. [ka] (In formula (14), R 14 , R 15 , R 16 , R 17 Each of these is independently a hydrogen atom and a linear or branched alkyl group having 1 to 6 carbon atoms, and not all of them are hydrogen atoms at the same time. 18(This refers to an alkylene group having 2 to 5 carbon atoms, either linear or methyl-branched.)

[0062] Examples of copper compounds used as catalyst components are listed below. Suitable copper compounds include cuprous compounds, cupric compounds, or mixtures thereof. Examples of cupric compounds include cupric chloride, cupric bromide, cupric sulfate, and cupric nitrate. Examples of cuprous compounds include cuprous chloride, cuprous bromide, cuprous sulfate, and cuprous nitrate. Among these, particularly preferred metallic compounds are cuprous chloride, cupric chloride, cuprous bromide, and cupric bromide. These copper salts may also be synthesized at the time of use from oxides (e.g., cuprous oxide), carbonates, hydroxides, and corresponding halogens or acids. A frequently used method is to prepare them by mixing the previously exemplified cuprous oxide with hydrogen halides (or solutions of hydrogen halides).

[0063] 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, and tetraethylammonium iodide. These can be used as aqueous solutions or in solutions with a suitable solvent. These halogen compounds can be used individually or in combination of two or more. Preferred halogen compounds are aqueous solutions of hydrogen chloride and aqueous solutions of hydrogen bromide.

[0064] The amount of these compounds used is not particularly limited, but it is preferably 2 to 20 times the amount of halogen atoms relative to the molar amount of copper atoms, and the preferred amount of copper atoms to use per 100 moles of phenol compound added to the polymerization reaction is in the range of 0.02 moles to 0.6 moles.

[0065] Next, we list examples of diamine compounds that serve as catalyst components. 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 Examples include methyl ethylenediamine, N,N'-n-butylethylenediamine, Ni-butylethylenediamine, N,N'-i-butylethylenediamine, Nt-butylethylenediamine, N,N'-t-butylethylenediamine, N,N,N'-tetramethyl-1,3-diaminopropane, N,N,N'-trimethyl-1,3-diaminopropane, N,N'-dimethyl-1,3-diaminopropane, N-methyl-1,3-diaminopropane, N,N,N',N'-tetramethyl-1,3-diamino-1-methylpropane, N,N,N',N'-tetramethyl-1,3-diamino-2-methylpropane, N,N,N',N'-tetramethyl-1,4-diaminobutane, and N,N,N',N'-tetramethyl-1,5-diaminopentane. For this embodiment, preferred diamine compounds are those in which the alkylene group connecting two nitrogen atoms has two or three carbon atoms. The amount of these diamine compounds used is not particularly limited, but it is preferably in the range of 0.01 moles to 10 moles per 100 moles of the phenol compound added to the polymerization reaction.

[0066] In this embodiment, the polymerization catalyst may include primary amines and secondary monoamines as constituent components. Examples of secondary monoamines, but not limited to the following, include dimethylamine, diethylamine, di-n-propylamine, di-i-propylamine, di-n-butylamine, di-i-butylamine, di-t-butylamine, dipentylamines, dihexylamines, dioctylamines, didecylamines, dibenzylamines, methylethylamine, methylpropylamine, methylbutylamine, cyclohexylamine, N-phenylmethanolamine, N-phenylethanolamine, N-phenylpropanolamine, N-(m-methylphenyl)ethanolamine, N-(p-methylphenyl)ethanolamine, N-(2',6'-dimethylphenyl)ethanolamine, N-(p-chlorophenyl)ethanolamine, N-ethylaniline, N-butylaniline, N-methyl-2-methylaniline, N-methyl-2,6-dimethylaniline, and diphenylamine.

[0067] The polymerization catalyst in this embodiment may also include a tertiary monoamine compound. A tertiary monoamine compound is an aliphatic tertiary amine, including alicyclic tertiary amines. Examples include trimethylamine, triethylamine, tripropylamine, tributylamine, triisobutylamine, dimethylethylamine, dimethylpropylamine, allyldiethylamine, dimethyl-n-butylamine, diethylisopropylamine, and N-methylcyclohexylamine. These tertiary monoamines may be used individually or in combination of two or more types. The amount used is not particularly limited, but it is preferably in the range of 15 moles or less per 100 moles of the phenol compound added to the polymerization reaction.

[0068] In this embodiment, there are no limitations on adding surfactants that are conventionally known to have an effect of improving polymerization activity. Examples of such surfactants include trioctylmethylammonium chloride, known by the trade names Aliquat336 and Capriquat.

[0069] In this embodiment, the oxygen-containing gas used in polymerization can be pure oxygen, a mixture of oxygen and an inert gas such as nitrogen in any proportion, air, or a mixture of air and an inert gas such as nitrogen in any proportion. While atmospheric pressure is sufficient for the system pressure during the polymerization reaction, it can be reduced or increased as needed.

[0070] The polymerization temperature is not particularly limited, but if it is too low, the reaction will not proceed easily, and if it is too high, the reaction selectivity may decrease or a gel may form. Therefore, it is in the range of 0 to 60°C, preferably 10 to 40°C.

[0071] In the method for producing polyphenylene ether, polymerization can also be carried out in a poor solvent such as alcohol.

[0072] (Copper extraction and by-product removal process) In this embodiment, there are no particular restrictions on the post-treatment method after the polymerization reaction is completed. Typically, an acid such as hydrochloric acid or acetic acid, or ethylenediaminetetraacetic acid (EDTA) and its salts, nitrilotriacetic acid and its salts, etc., are added to the reaction solution to deactivate the catalyst. In addition, the removal of divalent phenol by-products generated by the polymerization of polyphenylene ether can be carried out using conventionally known methods. If the metal ions that act as catalysts are substantially deactivated as described above, the mixture can be decolorized simply by heating it. Alternatively, it is also possible to add the required amount of a known reducing agent. Examples of known reducing agents include hydroquinone and sodium dithionite.

[0073] (liquid-liquid separation process) In the method for producing polyphenylene ether, water may be added to extract the compound from which the copper catalyst has been deactivated, followed by liquid-liquid separation into an organic phase and an aqueous phase. The copper catalyst may then be removed from the organic phase by removing the aqueous phase. This liquid-liquid separation step is not particularly limited, but examples include static separation and separation by centrifugation. To promote the above liquid-liquid separation, known surfactants may be used.

[0074] (concentration / drying process) Next, in the method for producing polyphenylene ether according to this embodiment, the organic phase containing the polyphenylene ether after liquid-liquid separation may be concentrated and dried by volatilizing the solvent.

[0075] Methods for volatilizing the solvent contained in the organic phase are not particularly limited, but include methods such as transferring the organic phase to a high-temperature concentration tank and distilling off the solvent to concentrate it, or using equipment such as a rotary evaporator to distill off toluene and concentrate it.

[0076] The drying temperature in the drying process is preferably at least 60°C, more preferably 80°C or higher, even more preferably 120°C or higher, and most preferably 140°C or higher. Drying polyphenylene ether at a temperature of 60°C or higher efficiently reduces the content of high-boiling point volatile components in the polyphenylene ether powder.

[0077] To efficiently obtain polyphenylene ether, methods such as increasing the drying temperature, increasing the vacuum level in the drying atmosphere, and stirring during drying are effective, but increasing the drying temperature is particularly preferable from the viewpoint of manufacturing efficiency. In the drying process, it is preferable to use a dryer equipped with a mixing function. Examples of mixing functions include agitation type and tumbling type dryers. This allows for a larger processing volume and maintains high productivity.

[0078] (Denaturation reaction process) There are no limitations on the method for introducing functional groups to the hydroxyl groups of unmodified polyphenylene ether. For example, it can be obtained by the formation of an ester bond between the hydroxyl groups 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. For example, a. reaction between a carboxylic acid halide and the 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, d. transesterification reaction, etc. Method a., reaction with a carboxylic acid halide is one of the most common methods. As the carboxylic acid halide, chlorides and bromides are generally used, but other halogens may also be used. The reaction may be a direct reaction with the hydroxyl group or a reaction with an alkali metal salt of the hydroxyl group. Since acids such as hydrogen halides are generated in the direct reaction between a carboxylic acid halide and the hydroxyl group, a weak base such as an amine may be present to trap the acid. In the reaction with carboxylic acid anhydride (b) and the direct reaction with carboxylic acid (c), compounds such as carbodiimides or dimethylaminopyridine may be present to activate the reaction site and promote the reaction. In the case of the transesterification reaction (d), it is desirable to remove the alcohols produced as needed. Known metal catalysts may also be present to promote the reaction. After the reaction, the polymer solution may be washed with water, an acidic or alkaline aqueous solution to remove by-products such as amine salts, or the polymer solution may be dropped into a poor solvent such as an alcohol and the target product may be recovered by reprecipitation. Alternatively, after washing the polymer solution, the solvent may be removed under reduced pressure and the polymer may be recovered.

[0079] The method for producing modified polyphenylene ether according to this embodiment is not limited to the method for producing modified polyphenylene ether according to this embodiment described above, and the order and number of times of the above-described oxidative polymerization step, copper extraction and by-product removal step, liquid-liquid separation step, and concentration and drying step may be adjusted as appropriate.

[0080] <Resin composition> The resin composition according to this embodiment comprises the polyphenylene ether, a crosslinking agent, and an organic peroxide, and optionally further comprises a thermoplastic resin, a flame retardant, other additives, a solvent, etc. The components of the resin composition according to this embodiment are described below.

[0081] <Crosslinking agent> In the resin composition of this embodiment, any crosslinking agent having the ability to cause or promote a crosslinking reaction can be used. Preferably, the crosslinking agent has a number average molecular weight of 4,000 or less. When the number average molecular weight of the crosslinking agent is 4,000 or less, the increase in viscosity of the resin composition can be suppressed, and good resin fluidity can be obtained during heat molding. The number average molecular weight may be a value measured by a general molecular weight measurement method, specifically a value measured using GPC, etc.

[0082] From the viewpoint of crosslinking reaction, the crosslinking agent preferably has an average of two or more carbon-carbon unsaturated double bonds per molecule. The crosslinking agent may be composed of one type of compound or two or more types of compounds. As used herein, "carbon-carbon unsaturated double bond" refers to a double bond located at the branched end of the main chain when the crosslinking agent is a polymer or oligomer. An example of a carbon-carbon unsaturated double bond is the 1,2-vinyl bond in polybutadiene.

[0083] When the number-average molecular weight of the crosslinking agent is less than 600, the average number of carbon-carbon unsaturated double bonds per molecule of the crosslinking agent is preferably 2 to 4. When the number-average molecular weight of the crosslinking agent is 600 or more and less than 1,500, the average number of carbon-carbon unsaturated double bonds per molecule of the crosslinking agent is preferably 4 to 26. When the number-average molecular weight of the crosslinking agent is 1,500 or more and less than 4,000, the average number of carbon-carbon unsaturated double bonds per molecule of the crosslinking agent is preferably 26 to 60. When the number-average molecular weight of the crosslinking agent is within the above range, having a number of carbon-carbon unsaturated double bonds equal to or greater than the specified value further enhances the reactivity of the crosslinking agent in the resin composition of this embodiment, further improves the crosslinking density of the cured resin composition, and as a result, provides even better heat resistance. On the other hand, when the number-average molecular weight of the crosslinking agent is within the above range, having a number of carbon-carbon unsaturated double bonds equal to or less than the specified value further enhances the resin fluidity during heat molding.

[0084] Examples of crosslinking agents include triallyl isocyanurate compounds such as triallyl isocyanurate (TAIC), triallyl cyanurate compounds such as triallyl 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, vinyl benzyl compounds such as divinylbenzene having a vinyl benzyl group in the molecule, polyfunctional maleimide compounds having two or more maleimide groups in the molecule such as 4,4'-bismaleimidediphenylmethane, polyfunctional acrylates having two or more acrylic groups in the molecule such as tricyclodecanedimethanol diacrylate, and polyfunctional methacrylates having two or more acrylic or methacrylic groups in the molecule such as tricyclodecanedimethanol dimethacrylate. These crosslinking agents can be used individually or in combination of two or more. The crosslinking agent preferably contains at least one compound selected from the group consisting of triallyl cyanurate, triallyl isocyanurate, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, tricyclodecanedimethanol dimethacrylate, and polybutadiene. By containing at least one of the compounds described above as the crosslinking agent, the resin composition tends to have even better compatibility and coating properties between the crosslinking agent and polyphenylene ether, and to have even better substrate properties when mounted on an electronic circuit board.

[0085] 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, from the viewpoint of further improving the compatibility between the crosslinking agent and modified polyphenylene ether, the coatability of the resin composition, and the characteristics of the mounted electronic circuit board.

[0086] <Organic peroxide> In this embodiment, any organic peroxide having the ability to promote the polymerization reaction of a resin composition containing polyphenylene ether and a crosslinking agent can be used. Examples of organic peroxides include 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, and trimethylsilyltriphenylsilyl peroxide. Furthermore, radical-generating agents such as 2,3-dimethyl-2,3-diphenylbutane can also be used as reaction initiators for the resin composition. 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 from the viewpoint of providing a cured product with excellent heat resistance and mechanical properties, and furthermore, a low dielectric loss tangent (and preferably a low dielectric constant).

[0087] The 1-minute half-life temperature of the organic peroxide is preferably 155 to 185°C, more preferably 160 to 180°C, and even more preferably 165 to 175°C. In this specification, the 1-minute half-life temperature is the temperature at which the time it takes for the organic peroxide to decompose and its amount of reactive oxygen to be halved is 1 minute. The 1-minute half-life temperature is a value that can be confirmed by dissolving the organic peroxide in a radical-inert solvent, such as benzene, to a concentration of 0.05 to 0.1 mol / L, and then thermally decomposing the organic peroxide solution under a nitrogen atmosphere.

[0088] When the half-life temperature of the organic peroxide is 155°C or higher, the reaction with the crosslinking agent begins only after the polyphenylene ether-containing resin composition has been sufficiently melted when subjected to heat and pressure molding, resulting in a tendency towards excellent moldability. On the other hand, when the half-life temperature of the organic peroxide is 185°C or lower, the decomposition rate of the organic peroxide under normal heat and pressure molding conditions (e.g., a maximum temperature of 200°C) is sufficient, allowing the crosslinking reaction with the crosslinking agent to proceed efficiently and slowly, thus enabling the formation of a cured product with good electrical properties (especially dielectric loss tangent).

[0089] Examples of organic peroxides with a 1-minute half-life temperature in the range of 155-185°C include t-hexylperoxyisopropyl monocarbonate (155.0°C), t-butylperoxy-3,5,5-trimethylhexanoate (166.0°C), t-butylperoxylaurate (159.4°C), t-butylperoxyisopropyl monocarbonate (158.8°C), t-butylperoxy-2-ethylhexyl monocarbonate (161.4°C), t-hexylperoxybenzoate (160.3°C), and 2,5-dimethyl-2,5-di(benzoylperoxy)hexane (158.2°C). Examples include t-butylperoxyacetate (159.9°C), 2,2-di-(t-butylperoxy)butane (159.9°C), t-butylperoxybenzoate (166.8°C), n-butyl4,4-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).

[0090] The content of organic peroxide is preferably 0.05 parts by mass or more, more preferably 0.5 parts by mass or more, or 1 part by mass or more, based on 100 parts by mass of the total of polyphenylene ether and the crosslinking agent, from the viewpoint of being able to increase the reaction rate, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, from the viewpoint of being able to keep the dielectric constant and dielectric loss tangent of the resulting cured product low. Similarly, the content of organic peroxide is preferably 0.05 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 5 parts by mass or less, even more preferably 1 part by mass or more and 4.5 parts by mass or less, based on 100 parts by mass of the total of polyphenylene ether and the crosslinking agent.

[0091] <Thermoplastic resin> The resin composition preferably includes a thermoplastic resin. The thermoplastic resin is preferably at least one selected from the group consisting of block copolymers of vinyl aromatic compounds and olefin-based alkene compounds and their hydrogenated products (hydrogenated block copolymers obtained by hydrogenating block copolymers of vinyl aromatic compounds and olefin-based alkene compounds), and homopolymers of vinyl aromatic compounds. The content of units derived from vinyl aromatic compounds in the block copolymer or its hydrogenated product is preferably 20% by mass or more, more preferably 22% by mass or more, and can be 99% by mass or less. When the content of units derived from vinyl aromatic compounds in the block copolymer or its hydrogenated product is 20% by mass or more, the compatibility with polyphenylene ether is further improved, and the adhesion strength with metal foil tends to be further improved.

[0092] Examples of vinyl aromatic compounds include any compound having an aromatic ring and a vinyl group in its molecule, such as styrene. Examples of olefinic alkene compounds include any alkene having a linear or branched structure in its molecule, such as ethylene, propylene, butylene, isobutylene, butadiene, and isoprene. Among these, the thermoplastic resin is preferably at least one selected from the group consisting of styrene-butadiene block copolymer, styrene-ethylene-butadiene block copolymer, styrene-ethylene-butylene block copolymer, styrene-butadiene-butylene block copolymer, styrene-isoprene block copolymer, styrene-ethylene-propylene block copolymer, styrene-isobutylene block copolymer, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-ethylene-butadiene block copolymer, hydrogenated styrene-butadiene-butylene block copolymer, hydrogenated styrene-isoprene block copolymer, and styrene homopolymer (polystyrene), and more preferably one or more selected from the group consisting of styrene-butadiene block copolymer, hydrogenated styrene-butadiene block copolymer, and polystyrene.

[0093] The hydrogenation rate in the above-mentioned hydrogenated product is not particularly limited, and some carbon-carbon unsaturated double bonds derived from the olefinic alkene compound may remain.

[0094] The weight-average molecular weight of the thermoplastic resin is preferably 10,000 to 300,000, more preferably 20,000 to 290,000, and even more preferably 30,000 to 280,000. A weight-average molecular weight of 10,000 or more tends to result in the resin composition of this embodiment exhibiting superior heat resistance upon curing. A weight-average molecular weight of 300,000 or less tends to result in the resin composition of this embodiment exhibiting superior resin fluidity during heat molding. The weight-average molecular weight is determined by the method described in the examples below.

[0095] The content of thermoplastic resin is preferably 2 to 20 parts by mass, more preferably 3 to 19 parts by mass, even more preferably 4 to 18 parts by mass, and particularly preferably 5 to 17 parts by mass, based on 100 parts by mass of the total of polyphenylene ether and the crosslinking agent. When the content is 2 parts by mass or more, the resin composition of this embodiment tends to have even better low dielectric constant, low dielectric loss tangent, and adhesion to metal foil when cured. When the content is 20 parts by mass or less, the resin composition of this embodiment tends to have even better resin fluidity when heat molded. Also, from a similar viewpoint, the content of thermoplastic resin is preferably 2 to 20 parts by mass, more preferably 3 to 19 parts by mass, based on 100 parts by mass of the total of polyphenylene ether and the crosslinking agent.

[0096] The resin composition of this embodiment may also include thermoplastic resins other than those described above, having the same type and weight-average molecular weight.

[0097] <Flame retardant> The resin composition of this embodiment preferably contains a flame retardant. The flame retardant is not particularly limited as long as it does not become miscible with other components in the resin composition after curing, from the viewpoint of improving heat resistance. Preferably, the flame retardant does not become miscible with polyphenylene ether and / or crosslinking agents in the resin composition after curing. 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-dibromoviphenyl, and ethylenebistetrabromophthalimide; and phosphorus-based flame retardants such as resorcinol bis-diphenyl phosphate and resorcinol bis-dixylenyl phosphate. These flame retardants may be used individually or in combination of two or more. Among these, decabromodiphenylethane is preferred as the flame retardant from the viewpoint of superior compatibility between the flame retardant and modified polyphenylene ether, coating properties of the resin composition, and characteristics of the mounted electronic circuit board.

[0098] The amount of flame retardant is not particularly limited, but from the viewpoint of maintaining flame retardancy at the V-0 level of UL standard 94, it is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, per 100 parts by mass of the total of the polyphenylene ether resin and the crosslinking agent. Furthermore, from the viewpoint of maintaining a low dielectric loss tangent of the resulting cured product (and preferably also maintaining a low dielectric constant), the amount of flame retardant is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, and even more preferably 40 parts by mass or less.

[0099] <Silica Filler> The resin composition of this embodiment may contain silica filler. Examples of silica filler include natural silica, fused silica, synthetic silica, amorphous silica, aerosil, and hollow silica. The silica filler content can be 10 to 100 parts by mass per 100 parts by mass of the total of polyphenylene ether and crosslinking agent. The silica filler may also be surface-treated with a silane coupling agent or the like.

[0100] The resin composition of this embodiment may further contain additives such as heat stabilizers, antioxidants, UV absorbers, surfactants, lubricants, and solvents, in addition to flame retardants and silica fillers. When the resin composition of this embodiment contains a solvent, it may be in the form of a varnish in which the solid components in the resin composition are dissolved or dispersed in the solvent, and a resin film can be formed from the resin composition of this embodiment.

[0101] <Solvent> The resin composition of this embodiment may contain a solvent. From the viewpoint of solubility, preferred solvents include aromatic compounds such as toluene and xylene, methyl ethyl ketone (MEK), cyclopentanone, cyclohexanone, and chloroform. These solvents may be used individually or in combination of two or more.

[0102] <Prepreg> The prepreg of this embodiment is a composite of a substrate and the resin composition of this embodiment, and the resin composition of this embodiment may be impregnated into or coated onto the substrate. The method for manufacturing the prepreg is not particularly limited, but for example, it can be obtained by impregnating the substrate with a resin composition (varnish) containing a solvent, and then drying off the solvent using a hot air dryer or the like.

[0103] Examples of substrates include various glass cloths such as roving cloth, cloth, chopped mat, and surfacing mat; asbestos cloth, metal fiber cloth, and other synthetic or natural inorganic fiber cloths; woven or nonwoven fabrics obtained from liquid crystal fibers such as fully aromatic polyamide fibers, fully aromatic polyester fibers, and polybenzoxazole fibers; natural fiber cloths such as cotton cloth, linen cloth, and felt; natural cellulose-based substrates such as carbon fiber cloth, kraft paper, cotton paper, and cloths obtained from paper-glass blended yarns; and polytetrafluoroethylene porous films. Glass cloth is preferred among these. These substrates may be used individually or in combination of two or more.

[0104] The proportion of solid content (components of the resin composition other than the solvent) of the resin composition in the prepreg of this embodiment is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass. When the above proportion is 30% by mass or more, the insulation reliability tends to be even better when the prepreg is used for electronic circuit boards, etc. When the above proportion is 80% by mass or less, the mechanical properties such as the flexural modulus tend to be even better in applications such as electronic circuit boards.

[0105] <Metal-clad laminate> The metal-clad laminate of this embodiment is obtained by laminating and curing the resin composition or resin film of this embodiment or the prepreg of this embodiment with a metal foil. The metal-clad laminate preferably has a form in which the cured prepreg (hereinafter also referred to as the "cured composite") and the metal foil are laminated and in close contact, and is suitably used as a material for electronic substrates. Examples of metal foils include aluminum foil and copper foil, and among these, copper foil is preferred because of its low electrical resistance. The cured composite combined with the metal foil may be one or multiple sheets, and depending on the application, the metal foil is layered on one or both sides of the composite to process it into a laminate.

[0106] One method for manufacturing a metal-clad laminate is to form a composite (e.g., the prepreg described above) composed of a resin composition and a substrate, then layer this with metal foil, and finally cure the resin composition to obtain a laminate in which a cured laminate and metal foil are laminated. One particularly preferred application of the above metal-clad laminate is a printed circuit board. In the case of a printed circuit board, it is preferable that at least a portion of the metal foil is removed from the metal-clad laminate.

[0107] <Printed wiring board> The printed circuit board of this embodiment has a portion of the metal foil removed from a metal-clad laminate. The printed circuit board of this embodiment can typically be formed by a pressure-heat molding method using the prepreg of the present invention described above. The base material can be the same as that described above regarding the prepreg. The printed circuit board of this embodiment, by containing the resin composition of this embodiment, has excellent heat resistance and electrical properties (low dielectric constant and low dielectric loss tangent), can further suppress fluctuations in electrical properties due to environmental changes, and has excellent insulation reliability and mechanical properties. [Examples]

[0108] The embodiment will be described in more detail below based on the following examples, but this embodiment is not limited to the following examples.

[0109] First, the measurement methods and evaluation criteria for each physical property are described below.

[0110] <Analysis of polyphenylene ether> (1) Reducing viscosity of polyphenylene ether (ηsp / c) A 0.5 g / dL chloroform solution of polyphenylene ether was prepared, and its reduced viscosity (ηsp / c) (dL / g) at 30°C was determined using an Ubbelohde viscous tube.

[0111] (2) Number average molecular weight (Mn) of polyphenylene ether As the measuring instrument, a gel permeation chromatography system (Shimadzu Corporation, LC-2030C Plus) was used to create a calibration curve using standard polystyrene and ethylbenzene. This calibration curve was then used to measure the number-average molecular weight (Mn) of the obtained modified polyphenylene ethers. The standard polystyrenes used had molecular weights of 3,650,000, 2,170,000, 1,090,000, 681,000, 204,000, 52,000, 30,200, 13,800, 3,360, 1,300, and 550.

[0112] The column used consisted of two Showa Denko K-805L columns connected in series. Chloroform was used as the solvent, with a solvent flow rate of 1.0 mL / min and a column temperature of 40°C. A 1 g / L chloroform solution of modified polyphenylene ether was prepared and used as the sample for measurement. The UV wavelength of the detection unit was set to 254 nm for standard polystyrene and 283 nm for polyphenylene ether. Based on the above measurement data, the number-average molecular weight (Mn) (g / mol) was calculated from the percentage of peak areas on the curve showing the molecular weight distribution obtained by GPC.

[0113] (3) Number of OH groups in polyphenylene ether 5.0 mg of polyphenylene ether was weighed. This weighed polyphenylene ether was then dissolved in 25 mL of methylene chloride. To 2.0 mL of the prepared solution, 150 μL of an ethanol solution of 2% by mass of tetraethylammonium hydroxide (TEAH) was added, and the absorbance (Abs) at 318 nm was measured using a UV spectrophotometer (Hitachi, Ltd.: U-3210 model) (using an absorbance measurement cell with a cell length of 1 cm). Based on the measurement results, the number of OH groups obtained from the absorbance was determined using the following formula (1). Number of OH groups (μmol / g)=[(25×Abs) / (ε×5)]×10 6 ...Formula (1) (Here, ε represents the extinction coefficient, which is 4700 L / mol·cm.)

[0114] (4) Number of OH groups per molecule of polyphenylene ether The number of OH groups per molecule of polyphenylene ether was determined using the number-average molecular weight obtained by gel permeation chromatography (details are described in (2) above) and the following formula (2). Average number of hydroxyl groups per molecule (groups / molecule) = (number-average molecular weight determined using gel permeation chromatography) × (number of OH groups obtained from absorbance) / 10 6 ...Formula (2)

[0115] (5) In the 1H-NMR measurement results obtained by adding 1% by mass of 1,3,5-trimethoxybenzene to polyphenylene ether, the ratio of the integrated value of the peak appearing at 7.6-8.3 ppm to the integrated value of the peak originating from 1,3,5-trimethoxybenzene (proportion of peroxide-derived peaks)

[0116] The polyphenylene ethers obtained in the examples and comparative examples were dissolved in deuterated chloroform, and 1% by mass of 1,3,5-trimethoxybenzene was used as an internal standard relative to the amount of polyphenylene ether added. 1 1H-NMR measurements were performed using a JEOL 500MHz instrument.

[0117] The cumulative value per proton of 1,3,5-trimethoxybenzene appearing at 6.08 ppm was defined as E, and the cumulative value of the peroxide-derived impurity peak area appearing in the region of 7.6 to 8.3 ppm was defined as G. By substituting these values ​​into the following formula (3), the proportion of peroxide-derived impurity peaks was analyzed.

number

[0118] (6) Long-term solubility in methyl ethyl ketone (MEK solubility) 2.0 g of polyphenylene ether and 8.0 g of methyl ethyl ketone were weighed into a transparent glass screw tube. The mixture was stirred at 20°C using a stirring bar and a magnetic stirrer. After confirming complete dissolution, the solution was allowed to stand for 1 day, and then its solubility was evaluated visually. ○ (Good): The solution remains clear. △: Some undissolved residue remains. × (Poor): Clearly undissolved or containing a large amount of insoluble matter.

[0119] (7) Long-term solubility in toluene (TL solubility) 2.0 g of polyphenylene ether and 8.0 g of toluene were weighed into a transparent glass screw tube. The mixture was stirred at 20°C using a stirring bar and a magnetic stirrer. After confirming complete dissolution, the solution was allowed to stand for 1 day, and then its solubility was evaluated visually. ○ (Good): The solution remains clear. △: Some undissolved residue remains. × (Poor): Clearly undissolved or containing a large amount of insoluble matter.

[0120] (Example 1) Synthesis of polyphenylene ether 1 (PPE1) A 40-liter jacketed polymerization tank, equipped with a sparger, stirring turbine blades, and baffles at the bottom for introducing oxygen-containing gas, and a reflux condenser in the vent gas line at the top of the polymerization tank, was prepared by adding 2.4 g of cupric oxide, 18.1 g of 47% by 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, 1740 g of 2,6-dimethylphenol, and 260 g of 2-tert-butyl-5-methylphenol while blowing nitrogen gas at a flow rate of 30.9 L / min to create a homogeneous solution. Next, dry air was introduced into the polymerization tank through the sparger at a rate of 21.0 L / min to start polymerization. Dry air was passed through for 105 minutes to obtain the polymerization mixture. The internal temperature was controlled to 40°C during polymerization. The polymerization mixture (polymerization solution) at the end of polymerization was in a homogeneous solution state.

[0121] The supply of dry air was stopped, and 25.9 g of tetrasodium ethylenediaminetetraacetate (reagent manufactured by Dojin Chemical Laboratories) 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 allowed 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 30% by mass.

[0122] The above solution was mixed with methanol in a ratio of 4 to the polymer solution, and the polymer was precipitated. Wet polyphenylene ether was obtained by vacuum filtration using a glass filter. The wet polyphenylene ether was then washed with methanol in a ratio of 4 to the wet polyphenylene ether. The above washing operation was repeated three times. After that, the wet polyphenylene ether was maintained at 140°C and 1 mmHg for 120 minutes to obtain dry polyphenylene ether. The obtained polyphenylene ether was subjected to the measurements described above. The results of each analysis are shown in Table 1.

[0123] (Example 2) Synthesis of polyphenylene ether 2 (PPE2) The procedure was carried out in the same manner as in Production Example 1, except that the phenolic raw materials were 1617 g of 2,6-dimethylphenol and 383 g of 2-tert-butyl-5-methylphenol. The results of each analysis are shown in Table 1.

[0124] (Example 3) Synthesis of polyphenylene ether 3 (PPE3) The phenol raw material was 2 kg of 2,6-dimethylphenol, and the procedure was carried out in the same manner as in Production Example 1, except that the air supply was stopped 100 minutes after the introduction of air. The results of each analysis are shown in Table 1.

[0125] (Example 4) Synthesis of polyphenylene ether 4 (PPE4) A 40-liter jacketed polymerization tank, equipped with a sparger, stirring turbine blades, and baffles at the bottom for introducing oxygen-containing gas, and a reflux condenser in the vent gas line at the top of the polymerization tank, was prepared by adding 2.5 g of cupric oxide, 18.9 g of 47% by mass aqueous solution of hydrogen bromide, 6.0 g of di-t-butylethylenediamine, 29.3 g of di-n-butylamine, 89.1 g of butyldimethylamine, 17.9 kg of ruen, 1909 g of 2,6-dimethylphenol, and 90.7 g of 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane while blowing nitrogen gas at a flow rate of 30.9 L / min to form a homogeneous solution. Next, dry air was introduced into the polymerization tank through the sparger at a rate of 21.0 L / min to start polymerization. Dry air was passed through for 120 minutes to obtain the polymerization mixture. The internal temperature was controlled to 40°C during polymerization. The polymerization mixture (polymerization solution) at the end of polymerization was in a homogeneous solution state.

[0126] The supply of dry air was stopped, and 27.0 g of tetrasodium ethylenediaminetetraacetate (reagent manufactured by Dojin Chemical Laboratories) 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 allowed to stand for 20 minutes, and the organic phase and aqueous phase were separated by liquid-liquid separation. The organic phase was dried using a rotary evaporator. The dried polyphenylene ether was maintained at 140°C and 1 mmHg for 240 minutes to obtain dry polyphenylene ether. The results of each analysis are shown in Table 1.

[0127] (Comparative Example 1) Synthesis of polyphenylene ether 5 (PPE5) The phenol raw material was 2 kg of 2,6-dimethylphenol, and the procedure was carried out in the same manner as in Production Example 1, except that the air supply was stopped 117 minutes after the introduction of air. The results of each analysis are shown in Table 1.

[0128] (Comparative Example 2) Synthesis of polyphenylene ether 6 (PPE6) In a 1.5 L jacketed reactor equipped with a sparger for introducing oxygen-containing gas at the bottom, stirring turbine blades and baffles, and a reflux condenser in the vent gas line at the top of the reactor, 0.04 g of cupric chloride dihydrate, 0.19 g of 35% hydrochloric acid, 1.70 g of N,N,N',N'-tetramethylpropanediamine, 502.6 g of methanol, 215.4 g of 1-butanol, and 80.0 g of 2,6-dimethylphenol were added. Then, while vigorously stirring, air was introduced into the reactor at a rate of 1.05 L / min through the sparger, and at the same time, the polymerization temperature was adjusted by passing a heat transfer medium through the jacket to maintain a temperature of 40°C. The polymerization solution gradually took on the form of a slurry.

[0129] 120 minutes after introducing air, the aeration of oxygen-containing gas was stopped, and a 50% aqueous solution of 0.23 g of ethylenediaminetetraacetic acid tripotassium salt (reagent manufactured by Dojin Chemical Research Institute) was added to the polymerization mixture. The mixture was reacted at 60°C for 2 hours. After the reaction was complete, wet polyphenylene ether was obtained by vacuum filtration using a glass filter. The wet polyphenylene ether was then washed with methanol in an amount such that the ratio of methanol to wet polyphenylene ether was 4. The above washing procedure was repeated three times. After that, the wet polyphenylene ether was maintained at 140°C and 1 mmHg for 120 minutes to obtain dry polyphenylene ether. The results of each analysis are shown in Table 1.

[0130] (Comparative Example 3) Synthesis of polyphenylene ether 7 (PPE7) The procedure was carried out in the same manner as in Example 4, except that the phenolic raw materials were 1663 g of 2,6-dimethylphenol and 337 g of 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane. The results of each analysis are shown in Table 1.

[0131] (Comparative Example 4) Synthesis of polyphenylene ether 8 (PPE8) A 500 ml three-necked flask was fitted with a three-way stopcock, a Liebig cone, and an isobaric dropping funnel. After purging the flask with nitrogen, 166 g of polyphenylene ether (S2O2A), 200 g of toluene, and 75 g of methyl ethyl ketone were added, followed by 33.7 g of 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane. A thermometer was placed in the flask, and while stirring with a magnetic stirrer, the flask was heated to 90°C in an oil bath to dissolve the polyphenylene ether. As an initiator, 56.3 g of a 40% by mass metaxylene solution (Nippon Oil & Fats Co., Ltd.: Niper BMT) of a mixture of benzoyl peroxide, benzoyl m-methylbenzoyl peroxide, and m-toluyl peroxide was diluted in 87.5 g of toluene and placed in an isobaric dropping funnel. The reaction commenced when the initiator solution began to be added dropwise to the flask. The initiator was added dropwise over 2 hours, and stirring was continued at 80°C for 4 hours after the addition.

[0132] The above solution was mixed with methanol in a ratio of 4 to the polymer solution, and the polymer was precipitated. Wet polyphenylene ether was obtained by vacuum filtration using a glass filter. The wet polyphenylene ether was then washed with methanol in a ratio of 4 to the wet polyphenylene ether. The above washing operation was repeated three times. After that, the wet polyphenylene ether was maintained at 140°C and 1 mmHg for 120 minutes to obtain dry polyphenylene ether. The results of each analysis are shown in Table 1.

[0133] [Table 1]

[0134] (Manufacturing Example 1) Synthesis of polyphenylene ether (PPE9) A 500 ml three-necked flask equipped with a nitrogen gas introduction line at the top of the reactor and a reflux condenser on the vent gas line at the top of the reactor was purged with nitrogen from the inside of the reactor. Then, 50 g of polyphenylene ether obtained in Comparative Example 3, 150 g of toluene, and 0.61 g of 4-dimethylaminopyridine were added. While stirring, 20 ml of triethylamine was added using a syringe. Then, 10.5 ml of methacryloyl chloride was taken with a syringe and added dropwise to the system at room temperature. After the addition was complete, the flask was heated in an oil bath for 1 hour and stirring was continued at 90°C. After that, it was heated further in an oil bath and the reaction was continued under reflux. After 4 hours from the start of reflux, heating was stopped and the reaction was stopped by adding 8 g of methanol after it had returned to room temperature. Next, the reaction solution was filtered using a glass filter to obtain a solution from which the by-product triethylammonium salt had been removed. The above solution was mixed with methanol in 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. The wet polyphenylene ether was then washed with methanol in an amount equal to 2.5. This washing procedure was repeated three times. Next, the wet polyphenylene ether was maintained at 100°C and 1 mmHg for 8 hours to obtain dry polyphenylene ether. The number of hydroxyl groups per molecule of the polyphenylene ether was measured using the method described above, and it was confirmed that the number of hydroxyl groups per molecule derived from the polyphenylene ether was less than 0.2. Furthermore, 1H NMR measurements were performed, and proton peaks originating from the olefin of the methacrylic group were confirmed, leading to the conclusion that the hydroxyl groups had been modified into methacrylic groups.

[0135] <Materials used in forming resin compositions and their cured products> (Polyphenylene ether) • Polyphenylene ethers 1-9 (PPE1-9) obtained in the above manufacturing example

[0136] (Crosslinking agent) • Triallyl cyanurate (Product name: TAIC, manufactured by Tokyo Chemical Industry Co., Ltd., number average molecular weight: 249.3, number of intramolecular unsaturated double bonds: 3) • 3,3'-Dimethyl-5,5'-Diethyl-4,4'-Diphenylmethanebismaleimide (Product name: BMI-5100, manufactured by Yamato Chemical Industries, Ltd., Number average molecular weight: 442.5, Number of intramolecular unsaturated double bonds: 2) Tricyclodecanedimethanol dimethacrylate (product name: DCP, manufactured by Shin-Nakamura Chemical Industry Co., Ltd., number average molecular weight: 332.4, number of intramolecular unsaturated double bonds: 2)

[0137] (organic peroxide) • Bis(1-tert-butylperoxy-1-methylethyl)benzene (product name Perbutyl P, manufactured by Nippon Oil & Fats Co., Ltd., half-life temperature at 1 minute: 175.4℃)

[0138] (thermoplastic resin) • Hydrogenated styrene-based thermoplastic resin (SEBS) (Product name: ToughTec H1041, manufactured by Asahi Kasei Corporation, weight-average molecular weight: approximately 90,000, styrene unit content: 32% by mass)

[0139] (Flame retardant) • Decabromodiphenylethane (product name: SAYTEX8010, manufactured by Albemarle)

[0140] (Filler) • Spherical silica (manufactured by Ryusen Co., Ltd.)

[0141] <Method for evaluating resin compositions> (1) Toluene immersion test The cured resin compositions produced in the examples and comparative examples were cut into pieces 5 mm wide and 50 mm long, immersed in a sufficient amount of toluene for 24 hours, and then their weight loss was evaluated. ○ (Good): Weight loss before and after immersion is less than 2% by mass. △: Weight loss of 2-10% by mass before and after immersion × (Defective): Weight loss of 10% or more before and after immersion.

[0142] (2) Dielectric constant and dielectric loss tangent of the cured resin composition The dielectric constant and dielectric loss tangent at 10 GHz of the cured resin compositions produced in the examples and comparative examples were measured using the split-cylinder method. A network analyzer (N5227B, KEYSIGHT TECHNOLOGIES) and a split-cylinder resonator (CR-710, EM Lab Co., Ltd.) were used as the measuring equipment.

[0143] The cured resin composition prepared by the method described below was cut into plates measuring 50 mm in width, 50 mm in length, and approximately 0.5 mm in thickness. Next, it was dried in an oven at 120°C ± 3°C for 1 hour, and then left to stand for 24 ± 2 hours in an environment of 23°C and 50 ± 2% relative humidity. After that, the dielectric constant and dielectric loss tangent were measured using the above measuring device in an environment of 23°C and 50 ± 2% relative humidity.

[0144] (3) Glass transition temperature (heat resistance) of the cured resin composition The dynamic viscoelasticity of the laminate was measured, and the temperature at which tanδ was maximized was determined as the glass transition temperature (Tg). A dynamic viscoelasticity analyzer (TA Instruments, ARES-G2) was used as the measuring device. A cured resin composition with a thickness of approximately 0.7 mm, prepared using the method described later, was cut into pieces 50 mm long and 10 mm wide to serve as test specimens, and measurements were performed in tensile mode at a frequency of 10 rad / s.

[0145] (4) Peel strength of the cured resin composition (peel strength N / mm) The stress was measured when peeling off the copper foil from a copper-clad laminate at a constant speed. A copper-clad laminate made using 18 μm thick copper foil (FZ-WS foil, manufactured by Furukawa Electric Industry Co., Ltd.), prepared using the method described below, was cut to a size of 10 mm wide x 120 mm long. Using an Autograph (AG-I20kN, manufactured by Shimadzu Corporation), the average load was measured when the copper foil was peeled off at a speed of 50 mm / min at a 90° angle to the removal surface, and the average of three measurements was calculated.

[0146] The following describes the methods for producing polyphenylene ether in each example and comparative example.

[0147] (Example 5) According to the composition and solvent shown in Table 1, a thermoplastic resin was added to 205 parts by mass of toluene, stirred, and dissolved. Then, a flame retardant, spherical silica, and PPE1 synthesized in Production Example 1 were added, and stirring was continued until PPE1 dissolved. Next, a crosslinking agent and an organic peroxide were added to the solution, and the mixture was stirred thoroughly to obtain a varnish. After impregnating L glass cloth with this varnish, the excess varnish was scraped off by passing it through a predetermined slit, and the mixture was dried in a drying oven at 130°C for a predetermined time to remove the toluene and obtain a prepreg. This prepreg was cut to a predetermined size, stacked in a predetermined number of pieces, and then copper foil (manufactured by Furukawa Electric Industry Co., Ltd., 18 μm thick, FZ-WS foil) was placed on both sides of the stacked prepregs. A copper-clad laminate was obtained by vacuum pressing with the stacked prepregs in this state. In this vacuum pressing process, first, the material was heated from room temperature at a rate of 2°C / min while maintaining a pressure of 40 kg / cm². After the temperature reached 200°C, the pressure was maintained at 40 kg / cm² for 60 minutes while keeping the temperature at 200°C. Next, a laminate was obtained by removing the copper foil from the copper-clad laminate by etching.

[0148] (Examples 6-7, Comparative Examples 5-8) Resin compositions, varnishes, and prepregs were obtained and evaluated according to the same method as in Example 1, except that the resin composition was changed as shown in Table 2.

[0149] [Table 2]

[0150] As shown in Tables 1 and 2, by using the polyphenylene ether with superior solvent solubility in methyl ethyl ketone compared to the comparative examples, we were able to obtain a resin composition with low varnish viscosity and excellent electrical properties and heat resistance of the cured product. [Industrial applicability]

[0151] The resin composition containing polyphenylene ether of the present invention has excellent solvent solubility and electrical properties, and therefore has industrial value for use in electronic materials and as a modifier.

Claims

1. The reduced viscosity (ηsp / c) measured with a chloroform solution at a concentration of 0.5 g / dL at 30°C was 0.13 to 0.30 dL / g. It has 100 to 330 μmol / g of OH groups, and the number of OH groups per molecule is 0.3 to 3.

0. Measurement was performed after adding 1% by mass of 1,3,5-trimethoxybenzene. 1 In the 1H-NMR measurement results, the ratio of the integrated value of the peak appearing at 7.6–8.3 ppm to the integrated value of the peak derived from 1,3,5-trimethoxybenzene was 0.1 or less. A polyphenylene ether characterized by containing a repeating unit derived from the phenol of the following formula (1) and a repeating unit derived from the phenol of the following formula (2). 【Chemistry 1】 (In formula (1), R 11 is independently a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted, an aryl group having 6 to 12 carbon atoms which may be substituted, or a halogen atom, and R 12 is independently a hydrogen atom, an hydrocarbon group having 1 to 6 carbon atoms which may be substituted, an aryl group having 6 to 12 carbon atoms which may be substituted, or a halogen atom.) 【Chemistry 2】 {In formula (2), R 22 is independently a hydrogen atom, an optionally substituted saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, an optionally substituted aryl group having 6 to 12 carbon atoms, or a halogen atom, and the two R 22s are not both hydrogen atoms, and R 21 is a substructure represented by the following formula (3). 【Transformation 3】 (In formula (3), R 31 is independently a linear alkyl group having 1 to 8 carbon atoms which may be substituted, or a cyclic alkyl structure having 1 to 8 carbon atoms formed by the bonding of two R 31 groups; R 32 is independently a linear alkyl group having 1 to 8 carbon atoms which may be substituted; b is independently 0 or 1; and R 33 is a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms which may be substituted, or a linear alkyl group having 1 to 8 carbon atoms which may be substituted.)

2. The polyphenylene ether according to claim 1, comprising, with respect to a total of 100 mol% of the repeating units derived from the phenol of formula (1) and the repeating units derived from the phenol of formula (2), more than 85 mol% and 95 mol% or less of the repeating units derived from the phenol of formula (1), and 5 mol% or more and less than 15 mol% of the repeating units derived from the phenol of formula (2).

3. The polyphenylene ether according to claim 1, comprising a structural unit derived from the phenol of the following formula (4). 【Chemistry 4】 {In equation (4), X is any a-valent linking group, a is an integer from 2 to 6, R 4 k is either a linear alkyl group having 1 to 8 carbon atoms or a substructure represented by the following formula (3), and is bonded to at least one of the carbon atoms at positions 2 or 6 of the benzene ring to which -O- is bonded, with the carbon atom at position 1 being the bonded carbon atom, and k is an integer from 1 to 4, independently of each other. 【Transformation 5】 (In formula (3), R 31 Each of these is independently a linear alkyl group having 1 to 8 carbon atoms, which may be substituted, or two R 31 It is a cyclic alkyl structure with 1 to 8 carbon atoms bonded together, R 32 Each is independently an alkylene group having 1 to 8 carbon atoms, which may be substituted, and each is independently 0 or 1, R 33 (This is a hydrogen atom, an optionally substituted C1-C8 alkyl group, or an optionally substituted phenyl group.)

4. A resin composition comprising the polyphenylene ether, crosslinking agent, and organic peroxide described in claim 1.

5. The resin composition according to claim 4, wherein the crosslinking agent has an average of two or more carbon-carbon unsaturated double bonds in one molecule, and the number average molecular weight of the crosslinking agent is 4,000 or less.

6. The resin composition according to claim 4, wherein the mass ratio of the polyphenylene ether to the crosslinking agent is 25:75 to 95:

5.

7. The resin composition according to claim 4, wherein the one-minute half-life temperature of the organic peroxide is 155°C to 185°C.

8. The resin composition according to claim 4, wherein the content of the organic peroxide is 0.05 parts by mass to 10 parts by mass, based on 100 parts by mass of the total mass of the polyphenylene ether and the crosslinking agent.

9. The resin composition according to claim 4, wherein the resin composition further comprises a thermoplastic resin, the thermoplastic resin being at least one selected from the group consisting of block copolymers of vinyl aromatic compounds and olefin-based alkene compounds and their hydrogenated products, and homopolymers of vinyl aromatic compounds, and the content of units derived from the vinyl aromatic compound in the block copolymer or its hydrogenated product is 20% by mass or more.

10. The resin composition according to claim 9, wherein the weight-average molecular weight of the thermoplastic resin is 10,000 to 300,000.

11. The resin composition according to claim 9, wherein the content of the thermoplastic resin is 2 to 20 parts by mass, based on a total mass of 100 parts by mass of the polyphenylene ether and the crosslinking agent.

12. The resin composition according to claim 4, wherein the resin composition further comprises a flame retardant, the flame retardant being immiscible with other components in the resin composition after curing.

13. A resin film comprising the resin composition according to any one of claims 4 to 12.

14. A prepreg that is a composite of a substrate and a resin composition according to any one of claims 4 to 12.

15. The prepreg according to claim 14, wherein the substrate is glass cloth.

16. A metal-clad laminate which is a laminate of a cured resin film according to claim 13 and a metal foil.

17. A metal-clad laminate which is a laminate of a cured prepreg according to claim 14 and a metal foil.

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