Method for producing polyphenylene ether

Abstract

The objective is to provide a manufacturing method that allows for the production of low-viscosity polyphenylene ethers while controlling the reaction activity during the production process. [Solution] In order to solve the above problems, the present invention includes a step of introducing an oxygen-containing gas into a solution containing phenol of formula (1) and phenol of formula (2) below and performing oxidative polymerization, wherein a vent gas cooler is provided at the top of the polymerization tank in which oxidative polymerization is performed, and the oxidative polymerization reaction temperature Tp, the coolant temperature Tc of the vent gas cooler, and the volume Vm of the reaction tank in which oxidative polymerization is performed are specified. 3 and the surface Am of the vent gas cooler 2 However, it satisfies a specific relationship. TIFF2026121283000027.tif32164

Description

Technical Field

[0001] The present invention relates to a method for producing polyphenylene ether.

Background Art

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

[0003] However, generally, high molecular weight (high viscosity) polyphenylene ether having a repeating unit derived from monohydric phenol represented by 2,6-dimethylphenol dissolves in a very highly toxic solvent such as chloroform, but is hardly soluble in high concentrations in aromatic solvents such as toluene known as good solvents at room temperature, and is insoluble in ketone solvents such as methyl ethyl ketone. Therefore, for example, when used as a wiring board material, it is difficult to handle with a resin varnish solution of toluene or methyl ethyl ketone.

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

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

[0006] Polyphenylene ethers are produced by blowing oxygen-containing gas into a phenol monomer solution. Generally, polymerization is carried out while simultaneously stirring the reaction solution to efficiently disperse the oxygen-containing gas. However, when stirring while blowing oxygen-containing gas into the reaction solution, the solvent is carried along with the blown gas discharged into the gas phase, and it is expected that the solid content concentration of the polymerization solution will change during the reaction. Therefore, condensers such as capacitors are often provided in the gas phase of the reactor to maintain a constant solid content concentration. However, the degree to which the change in solid content concentration of the solution during the reaction affects the polymerization reaction activity varies greatly depending on the structure of the polyphenylene ether being produced, thus requiring optimization of the production conditions. In particular, when producing relatively low-viscosity (low molecular weight) polyphenylene ethers, such as those used for printed circuit board materials, it is more difficult to control the molecular weight to the target level by changing the solid content concentration of the reaction solution. Furthermore, in the case of high molecular weight (high viscosity) polyphenylene ethers having repeating units derived from monovalent phenols such as 2,6-dimethylphenol used in Patent Document 1, the reaction activity of oxidative polymerization and its variability depending on the solid content concentration, as described above, have not been confirmed. This phenomenon is only observed when using phenol raw materials in which the ortho position of the hydroxyl group is unsubstituted, as used in Patent Document 2. However, Patent Document 2 does not disclose the reaction activity of oxidative polymerization or its variability, nor has it considered means to control it so that the target molecular weight can be obtained.

[0007] The present invention has been made in view of the above problems, and aims to provide a manufacturing method that can produce low-viscosity polyphenylene ether while controlling the reaction activity during the production of polyphenylene ether. [Means for solving the problem]

[0008] The present inventors, in order to solve the problems of the prior art described above, conducted diligent studies and have found a method that includes a step of introducing an oxygen-containing gas into a solution containing phenol having a specific structure and performing oxidative polymerization, and the relationship between the oxidative polymerization reaction temperature Tp and the refrigerant temperature Tc of the vent gas cooler, as well as the volume Vm of the reaction vessel in which oxidative polymerization is performed. 3 and surface propagation Am of the vent gas cooler 2 By controlling the relationship between these factors within a specific range, we discovered that it is possible to obtain a polyphenylene ether with low reducing viscosity while controlling the reaction activity during the production of polyphenylene ether, thus completing the present invention.

[0009] In other words, the present invention is as follows. [1] The process includes introducing an oxygen-containing gas into a solution containing phenol of formula (1) and phenol of formula (2) below to carry out oxidative polymerization, [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 formula (3). [ka] (In formula (3), R31 is, independently of each other, 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 Rs are bonded, and R 31 is, independently of each other, an alkylene group having 1 to 8 carbon atoms which may be substituted, b is, independently of each other, 0 or 1, and R 32 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.) 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.) A vent gas cooler is provided above the polymerization tank for performing the oxidative polymerization, and the relationship between the oxidative polymerization reaction temperature Tp and the refrigerant temperature Tc of the vent gas cooler satisfies the following formula (4), 10 °C ≤ Tp - Tc ≤ 70 °C ··· (4) The volume Vm of the reaction tank for performing the oxidative polymerization 3 and the heat transfer area Am of the vent gas cooler 2 satisfy the following formula (5), 0.05 ≤ V / A ≤ 5.0 ··· (5) A method for producing polyphenylene ether, characterized in that the reduced viscosity (ηsp / c) measured in a chloroform solution having a concentration of 0.5 g / dL at 30 °C of the obtained polyphenylene ether is 0.03 to 0.30 dL / g. [2] The oxidative polymerization reaction temperature Tp, the refrigerant temperature Tc of the vent gas cooler, the volume Vm of the reaction tank for performing the oxidative polymerization 3 and the heat transfer area Am of the vent gas cooler 2 satisfy the following formula (6), and the method for producing polyphenylene ether according to [1]. 10 ≤ (Tp - Tc)A / V ≤ 700 ··· (6) [3] A process for oxidative polymerization by introducing an oxygen-containing gas into a solution containing a phenol of the following formula (1) and a phenol of the following formula (2), [Chemical formula] (In formula (1), R<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 formula (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 a hydrogen atom, an optionally substituted C1-C8 alkyl group, or an optionally substituted phenyl group.) A vent gas cooler is provided at the top of the polymerization tank in which the oxidative polymerization is carried out. The relationship between the oxidation polymerization reaction temperature Tp and the refrigerant temperature Tc of the vent gas cooler satisfies the following equation (4): 10℃ ≤ Tp - Tc ≤ 70℃ ···(4) Volume LVm of the oxidative polymerization reaction solution 3 and the permeability FVm of the oxygen-containing gas 3 The relationship / min satisfies the following equation (7), 0.15 ≤ LV / FV ≤ 2.5 ···(7) A method for producing polyphenylene ether, characterized in that the reduced viscosity (ηsp / c) of the obtained polyphenylene ether, measured in a 0.5 g / dL chloroform solution at 30°C, is 0.03 to 0.30 dL / g. [4] The temperature of the oxidation polymerization reaction Tp, the refrigerant temperature of the vent gas cooler Tc, and the volume of the oxidation polymerization reaction solution LVm 3 and the permeability FVm of the oxygen-containing gas 3 A method for producing polyphenylene ether as described in [3], wherein the relationship / min satisfies the following formula (8). 25≦(Tp-Tc)FV / LV ≦470 (8) [5] A method for producing a polyphenylene ether according to any one of [1] to [4], characterized in that, with respect to a total of 100 mol% of the phenols of formula (1) and formula (2), the content ratio of the phenol of formula (1) is 70 mol% or more and less than 85 mol%, and the content of the phenol of formula (2) is more than 15 mol% and 30 mol% or less. [6] The phenol compound of formula (1) is 2,6-dimethylphenol, 2-methyl-6-ethylphenol, 2,6-diethylphenol, 2-ethyl-6-n-propylphenol, 2-methyl-6-chlorophenol, 2-methyl-6-bromophenol, 2-methyl-6-n-propylphenol, 2-ethyl-6-bromophenol, 2-methyl-6-n-butylphenol, 2,6-di-n-propylphenol, 2-ethyl-6-chlorophenol, 2-methyl-6-phenylphenol, 2, A method for producing polyphenylene ether according to any one of [1] to [5], characterized in that one or more are selected from the group consisting of 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. [7] A method for producing polyphenylene ether according to any one of [1] to [6], characterized in that the phenol compound of formula (2) is one or more selected from the group consisting of 2-isopropyl-5-methylphenol, 2-cyclohexyl-5-methylphenol, 2-tert-butyl-5-methylphenol, and 2-isobutyl-5-methylphenol. [8] A method for producing a polyphenylene ether according to any one of [1] to [7], characterized in that the substructure represented by formula (3) is a t-butyl group. [9] A method for producing polyphenylene ether according to any one of [1] to [8], further characterized by containing a phenol of the following formula (12). [ka] (In equation (12), 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 k is an integer from 1 to 4, independently of the others.

[10] The phenol of formula (12) above, A phenol compound having two phenol units in its molecule, selected from the group consisting of 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4,4'-methylenebis(2,6-dimethylphenol), bis(4-hydroxy-3-methylphenyl)sulfide, bis(4-hydroxy-3,5-dimethylphenyl)sulfone, α,α'-bis(4-hydroxy-3,5-dimethylphenyl)-1,4-diisopropylbenzene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, and 1,1-bis(2-methyl-4-hydroxy-5-t-butylphenyl)butane; or; 4,4'-[(3-hydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(3-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 4,4'-[(4-hydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(4-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 4,4'-[(2-hydroxy-3-methoxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(4-hydroxy-3-ethoxy [phenyl)methylene]bis(2,3,6-trimethylethylphenol), 4,4'-[(3,4-dihydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(3,4-dihydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 2,2'-[(4-hydroxyphenyl)methylene]bis(3,5,6-trimethylphenol), 4,4'-[4-(4-hydroxyphenyl)cyclohexylidene]bis(2,6-dimethylphenol), 4,4'-[(2-hydroxyphenyl)methylene] -Bis(2,3,6-trimethylphenol), 4,4'-[1-[4-[1-(4-hydroxy-3,5-dimethylphenyl)-1-methylethyl]phenyl]ethylidene]bis(2,6-dimethylphenol), 4,4'-[1-[4-[1-(4-hydroxy-3-fluorophenyl)-1-methylethyl]phenyl]ethylidene]bis(2,6-dimethylphenol), 2,6-bis[(4-hydroxy-3,5-dimethylphenyl)ethyl]-4-methylphenol, 2,6-bis[(4-hydroxy-2,3,6-trimethylphenyl] [(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- ris[(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'- Chilenbis[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], 4,4'-cyclohexyllidenbis[2-cyclohexyl-6-[(4-hydroxy-2-methyl-5-cyclohexylphenyl)methyl]phenol], 4,A method for producing polyphenylene ether according to any one of [1] to [9], characterized by a phenol compound having three or more phenol units in the molecule, selected from the group consisting of 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.

[11] A method for producing polyphenylene ether according to any one of [1] to

[10] , characterized in that the molecular weight distribution (Mw / Mn) of the polyphenylene ether determined by gel permeation chromatography (GPC) is 2.0 to 6.0.

[12] A step to set the target weight-average molecular weight of the obtained polyphenylene ether, A step of setting the polymerization time to obtain the target weight-average molecular weight polyphenylene ether, and The process includes oxidative polymerization during the aforementioned polymerization time, The polyphenylene ether obtained during the aforementioned polymerization time is characterized in that the weight-average molecular weight is within ±5% of the target weight-average molecular weight. A method for producing polyphenylene ether as described in any of [1] to

[11] .

[13] A step of setting the target weight-average molecular weight of the obtained polyphenylene ether, The process includes obtaining a polyphenylene ether with the target weight-average molecular weight through the oxidative polymerization step, A method for producing a polyphenylene ether according to any one of [1] to

[12] , characterized in that the polymerization time required to polymerize the polyphenylene ether having the target weight-average molecular weight is within ±5% of the average polymerization time. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a method for producing polyphenylene ether that allows control of the reaction activity during production, even when obtaining a low-viscosity polyphenylene ether. [Modes for carrying out the invention]

[0011] The following describes in detail embodiments for carrying out the present invention (hereinafter referred to as "this embodiment"). This embodiment is an example for explaining the present invention, and the present invention is not limited to this embodiment. The present invention can be implemented by modifying it as appropriate within the scope of its gist.

[0012] 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.

[0013] 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.

[0014] (Polyphenylene ether) The polyphenylene ether produced by the method for producing polyphenylene ether of this embodiment is obtained by oxidative polymerization of the phenol of formula (1) and the 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 12Each 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 a hydrogen atom, an optionally substituted C1-C8 alkyl group, or an optionally substituted phenyl group.

[0015] In the above equation (1), R 11 Each 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.

[0016] 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).

[0017] 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).

[0018] 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.

[0019] The raw material phenol used in this embodiment can have its structure identified by analyzing the resulting polyphenylene ether using techniques such as NMR and mass spectrometry. A specific method for identifying the structure of the 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 the polyphenylene ether can be achieved by combining electron ionization (EI) peak analysis of fragment ions with structural analysis by NMR.

[0020] Furthermore, in the manufacturing method according to this embodiment, it is preferable that the content ratio of phenol of formula (1) is 70 mol% or more and less than 85 mol% of the total phenol of formula (1) and formula (2) above, and the content ratio of phenol of formula (2) is more than 15 mol% and 30 mol% or less. By using the above proportions, the resulting polyphenylene ether can have excellent solvent solubility.

[0021] From a similar viewpoint, it is preferable that, with respect to a total of 100 mol% of the phenols of formula (1) and formula (2), the content ratio of phenol of formula (1) is 72 mol% or more and 84 mol% or less, and the content ratio of phenol of formula (2) is 16 mol% or more and 28 mol% or less, more preferably the content ratio of phenol of formula (1) is 74 mol% or more and 83.5 mol% or less, and the content ratio of phenol of formula (2) is 16.5 mol% or more and 26 mol% or less, and even more preferably the content ratio of phenol of formula (1) is 75 mol% or more and 83 mol% or less, and the content ratio of phenol of formula (2) is 17 mol% or more and 25 mol% or less.

[0022] Furthermore, since the phenol of formula (1) above 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 the phenol of formula (1) above in the resulting polyphenylene ether include repeating units having the structure of formula (9) below. [ka] (In formula (9), R 11 and R 12 This is the same as equation (1).

[0023] 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, the repeating units derived from the phenol of formula (2) have the structures of formulas (10) and (11) below, or combinations thereof. [ka] [ka] (R in equations (10) and (11)) 21 , R 22 This is the same as equation (2).

[0024] Furthermore, the raw materials may include phenol of the following formula (12). [ka] (In equation (12), 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 k is an integer from 1 to 4, independently of the others.

[0025] In the above equation (12), 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.

[0026] In the above formula (12), k is an integer between 1 and 4, preferably between 2 and 4.

[0027] Also, in equation (12) above, R 4It is preferable that the R bonded to the benzene ring is at position 2 and / or 6, with the carbon atom to which the -O- bond is bonded being at position 1. 4 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.

[0028] The polyphenylene ether may also include repeating units derived from the phenol of formula (12), as well as repeating units derived from the phenol of formula (1) and repeating units derived from the phenol of formula (2). In this case, R in equation (2) above 21 and R in equation (12) above 4 However, if both are substructures (functional groups) represented by formula (3) (i.e., both the phenol compound of formula (2) and the phenol compound of formula (12) are substituted with a substructure (functional group) represented by formula (3)), the structures of each substructure (functional group) represented by formula (3) may be the same or different.

[0029] Furthermore, in formula (12) 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.

[0030] As for X above, R is connected via a single bond or an ester bond, etc. 4 R 4 R 4Examples include α-valent heterocyclic skeletons bonded to a benzene ring.

[0031] 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.

[0032] In the above formula (12), a is an integer between 2 and 6, preferably between 2 and 4.

[0033] If the phenol of formula (12) does not have an unsubstituted ortho position, the structural unit derived from the phenol of formula (12) has the structure of formula (13) below, and if the phenol of formula (12) has an unsubstituted ortho position, the structural unit derived from the phenol of formula (12) has the structure of formula (13) below, the structure of formula (14) below, or a combination thereof. [ka] [ka] (R in equations (13) and (14)) 4 This is the same as equation (12).

[0034] The polyphenylene ether thus obtained preferably has a molecular weight distribution (Mw / Mn) of 2.0 to 6.0, more preferably 2.5 to 5.5, and even more preferably 3.0 to 5.0, as determined by gel permeation chromatography (GPC). A molecular weight distribution (Mw / Mn) of 2.0 or higher, as determined by gel permeation chromatography (GPC), improves the fluidity of polyphenylene ether. Furthermore, a molecular weight distribution (Mw / Mn) of 6.0 or lower improves the toughness of polyphenylene ether and enhances its mechanical properties.

[0035] Means for adjusting the molecular weight distribution of the polyphenylene ether to the above range include adjusting the polymerization temperature, adjusting the catalyst equivalent, and adjusting the monomer concentration in the reaction system, from the viewpoint of controlling polymerization reactivity. Among these, a method of gradually adding monomers to the reaction system is preferred for adjusting the monomer concentration in the reaction system. If the monomer concentration in the reaction system is high from the beginning, it is difficult to control the molecular weight of the resulting polymer because the reaction rate between monomers is fast. On the other hand, by adding monomers to the reaction system at an appropriate flow rate, the monomer concentration in the reaction system can be controlled, and the reaction rate can be easily controlled. As a result, a polymer having a molecular weight distribution within a desirable range can be obtained.

[0036] Furthermore, the polyphenylene ether obtained in this embodiment has a reduced viscosity (ηsp / c) of 0.03 to 0.30 dL / g, preferably 0.10 to 0.28 dL / g, and more preferably 0.16 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 0.03 dL / g or higher, measured in a 0.5 g / dL chloroform solution at 30°C, indicates high heat resistance and excellent dielectric properties derived from the polyphenylene ether structure. A reduced viscosity (ηsp / c) of 0.30 dL / g or lower ensures solubility in solvents such as toluene and methyl ethyl ketone. The aforementioned reduced viscosity can be measured by the measurement method described later.

[0037] (Method for producing polyphenylene ether) The method for producing polyphenylene ether according to this embodiment includes a step of introducing an oxygen-containing gas into a solution containing the phenol of formula (1) and the phenol of formula (2), preferably a solution further containing the phenol of formula (12), and carrying out oxidative polymerization (oxidative polymerization step).

[0038] Examples of phenol compounds of formula (1) above 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 phenol compound of formula (1) above may be used individually or in combination of multiple types.

[0039] Examples of the phenol compound of 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 phenol compound of formula (2) above may be used individually or in combination of multiple types.

[0040] Among the phenol compounds of formula (12) above, 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.

[0041] Furthermore, among the phenol compounds of formula (12) above, 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-Hyd [(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] [(nyl)cyclohexylidene]bis(2,6-dimethylphenol), 4,4'-[(2-hydroxyphenyl)methylene]-bis(2,3,6-trimethylphenol), 4,4'-[1-[4-[1-(4-hydroxy-3,5-dimethylphenyl)-1-methylethyl]phenyl]ethylidene]bis(2,6-dimethylphenol), 4,4'-[1-[4-[1-(4-hydroxy-3-fluorophenyl)-1-methylethyl]phenyl]ethylidene]bis(2,6-dimethylphenol), 2,6-bis[(4-hydroxy-3,5-dimethyl Phenyl)ethyl]-4-methylphenol, 2,6-bis[(4-hydroxy-2,3,6-trimethylphenyl)methyl]-4-methylphenol, 2,6-bis[(4-hydroxy-3,5,6-trimethylphenyl)methyl]-4-ethylphenol, 2,4-bis[(4-hydroxy-3-methylphenyl)methyl]-6-methylphenol, 2,6-bis[(4-hydroxy-3-methylphenyl)methyl]-4-methylphenol, 2,4-bis[(4-hydroxy-3-cyclohexylphenyl)methyl]-6-methylphenol, 2,4-bis[(4-hydroxy-3-methylphenyl)methyl]-6-cyclohexylphenol, 2,4-bis[(2-hydroxy-5-methylphenyl)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 phenol compound of formula (12) above may be used individually or in combination of multiple types.

[0042] The number of phenolic hydroxyl groups in the phenol compound of formula (12) 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.

[0043] 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 the solvent.

[0044] On the other hand, if the phenol in 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 a polyphenylene ether with an average of less than 3.0 hydroxyl groups per molecule can be obtained.

[0045] Furthermore, if the phenol in formula (2) has a bulky substituent at one of its ortho positions, even if 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.

[0046] Furthermore, 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 (12) to the total of the structures of formula (1) and formula (12). In other words, if the molar ratio of the structure of formula (2) or formula (12) is high, the molecular weight (reduced viscosity) can be lowered, and if the molar ratio of the structure of formula (2) or formula (12) is low, the molecular weight (reduced viscosity) can be adjusted to be higher.

[0047] 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.

[0048] 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; nitro compounds such as nitrobenzene; and the like.

[0049] As polymerization catalysts, generally known catalyst systems that can be used for the production of polyphenylene ethers can be used. Commonly known catalyst systems consist of a transition metal ion with redox potential 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 manganese compound and an amine compound, a cobalt compound and an amine compound, etc. Since the polymerization reaction proceeds efficiently under slightly alkaline conditions, a small amount of alkali or further amine compounds may be added.

[0050] Furthermore, preferred polymerization catalysts include catalysts comprising a copper compound, a halogen compound, and an amine compound as catalyst components, and more preferably catalysts containing a diamine compound represented by the following formula (15) as the amine compound. [ka] (In formula (15), 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.)

[0051] 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).

[0052] Examples of the halogen compounds include hydrogen chloride, hydrogen bromide, hydrogen iodide, sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium chloride, tetraethylammonium bromide, and tetraethylammonium iodide. These can also be used as aqueous solutions or 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.

[0053] 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.

[0054] Examples of the diamine compounds of the catalyst component include N,N,N',N'-tetramethylethylenediamine, N,N,N'-trimethylethylenediamine, N,N'-dimethylethylenediamine, N,N-dimethylethylenediamine, N-methylethylenediamine, N,N,N',N'-tetraethylethylenediamine, N,N,N'-triethylethylenediamine, N,N'-diethylethylenediamine, N,N'-diethylethylenediamine, N-ethylethylenediamine, N,N'-dimethyl-N'-ethylethylenediamine, N,N'-dimethyl-N-ethylethylenediamine, Nn-propylethylenediamine, N,N'-n-propylethylenediamine, Ni-propylethylenediamine, N,N'-i-propylethylenediamine, Nn Examples include -butylethylenediamine, 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 the 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.

[0055] Furthermore, the polymerization catalyst may contain primary amines and secondary monoamines as constituent components. Examples of secondary monoamines, but not limited to those listed below, 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.

[0056] The polymerization catalyst may also contain 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. 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.

[0057] In this embodiment, there are no restrictions 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.

[0058] In the method for producing polyphenylene ether according to this embodiment, oxidative polymerization is initiated by introducing an oxygen-containing gas into a reaction solution containing the raw material phenol, polymerization catalyst, and solvent. As the oxygen-containing gas used in the polymerization, 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 can be used. While atmospheric pressure is sufficient for the system pressure during the polymerization reaction, it can be reduced or increased as needed.

[0059] In the method for producing polyphenylene ether according to this embodiment, the oxidative polymerization includes a step of blowing the oxygen-containing gas into a reaction solution mainly composed of an organic solvent. It is known that when the oxygen-containing gas that has passed through the solution is vigorously discharged into the gas phase, it entrains a mist-like organic solvent (also called droplet entrainment). Therefore, in general oxidative polymerization methods, a cooler is often installed at the outlet (vent) of the oxygen-containing gas to prevent the organic solvent entrained with the oxygen-containing gas from being released into the atmosphere and resulting in loss. This cooler circulates a refrigerant such as cooling water or brine, which cools and condenses the organic solvent that has been carried to the vent along with the oxygen-containing gas, allowing it to be returned to the reaction vessel.

[0060] Furthermore, in the first embodiment of the method for producing polyphenylene ether according to this embodiment, the difference between the temperature of the polymerization reaction solution (Tp) and the refrigerant temperature of the vent gas cooler (Tc) (Tp-Tc) is in the range of 10 to 70°C (10°C ≤ Tp-Tc ≤ 70°C...(4)), preferably 20 to 65°C, more preferably 30 to 60°C, and even more preferably 35 to 50°C. By keeping the temperature difference between the refrigerant and the polymerization reaction solution within the range of 10 to 70°C (satisfying equation (4)), the solid content concentration of the reaction solution can be controlled within an appropriate range during the polymerization reaction, resulting in less variation in reaction activity and enabling the stable production of polyphenylene ether with the target molecular weight.

[0061] From a similar viewpoint, the transmission surface (A(m) of the vent gas cooler2 Volume of polymerization reactor relative to (V(m)) 3 The ratio (V / A) is in the range of 0.05 to 5.0 (0.05 ≤ V / A ≤ 5.0 ···(5)), preferably 0.07 to 4.5, more preferably 0.08 to 4.0, and even more preferably 0.09 to 3.0. By having a ratio (V / A) of the volume of the polymerization reactor (V) to the surface area (A) of the vent gas cooler in the range of 0.05 to 5.0 (satisfying equation (5)), the solid content concentration of the reaction solution can be controlled within an appropriate range during the polymerization reaction, resulting in less variation in reaction activity and enabling the stable production of polyphenylene ether with the target molecular weight.

[0062] The difference between the temperature of the polymerization reaction solution (Tp) and the refrigerant temperature of the vent gas cooler (Tc) (Tp-Tc), and the surface temperature of the vent gas cooler (A(m)) 2 Volume of polymerization reactor relative to (V(m)) 3 The value ((Tp-Tc)A / V) calculated by the quotient with the ratio (V / A) of )) preferably satisfies the following formula (6). 10≦(Tp-Tc)A / V≦700 (6) The calculated value ((Tp-Tc)A / V) is preferably between 10 and 700, more preferably between 12 and 600, and even more preferably between 14 and 500, as shown in formula (6) above. By adjusting the value ((Tp-Tc)A / V) to an appropriate range, the solid content concentration of the reaction solution can be controlled to an appropriate range during the polymerization reaction, resulting in less variation in reaction activity and enabling the stable production of polyphenylene ether with the target molecular weight.

[0063] In a second embodiment of the method for producing polyphenylene ether according to this embodiment, the difference between the temperature of the polymerization reaction solution (Tp) and the refrigerant temperature of the vent gas cooler (Tc) (Tp-Tc) is in the range of 10 to 70°C (10°C ≤ Tp-Tc ≤ 70°C...(4)), preferably 20 to 65°C, more preferably 30 to 60°C, and even more preferably 35 to 50°C.

[0064] Furthermore, since the droplet entrainment phenomenon in the production of polyphenylene ether described above is strongly correlated with the amount of oxygen-containing gas blown in, in this embodiment, the amount of oxygen-containing gas to permeate (FV(m)) 3 (L / min)) relative to the volume of polymerization reaction solution (LV(m³) 3 The ratio (LV / FV) is in the range of 0.15 to 2.5 (0.15 ≤ LV / FV ≤ 2.5 ···(7)), preferably 0.20 to 2.0, more preferably 0.25 to 1.7, and even more preferably 0.3 to 1.6. The amount of oxygen-containing gas that can be passed through (FV(m) 3 (m³ / min) is the rate at which air and nitrogen are blown into the polymerization tank. 3 It can be calculated by summing ( / min). By having a ratio (LV / FV) of the volume of the polymerization reaction solution to the volume of oxygen-containing gas permeable (FV) within the range of 0.15 to 2.5 (satisfying equation (7)), the solid content concentration of the reaction solution can be controlled within an appropriate range during the polymerization reaction, resulting in less variation in reaction activity and enabling the stable production of polyphenylene ether with the target molecular weight.

[0065] The difference between the temperature of the polymerization reaction solution (Tp) and the refrigerant temperature of the vent gas cooler (Tc) (Tp-Tc), and the amount of oxygen-containing gas to pass through (FV(m)) 3 (L / min)) relative to the volume of polymerization reaction solution (LV(m³) 3 The value ((Tp-Tc)FV / LV), calculated by the quotient of the ratio (LV / FV) of ), preferably satisfies the following formula (8). 25≦(Tp-Tc)FV / LV ≦470 (8) The calculated value ((Tp-Tc)FV / LV) is preferably between 25 and 470, more preferably between 30 and 300, and even more preferably between 40 and 200, as shown in formula (8). By adjusting the calculated value ((Tp-Tc)FV / LV) to an appropriate range, the solid content concentration of the reaction solution can be controlled to an appropriate range during the polymerization reaction, resulting in less variation in reaction activity and enabling the stable production of polyphenylene ether with the target molecular weight.

[0066] Furthermore, the manufacturing method in this embodiment is A step to set the target weight-average molecular weight of the resulting polyphenylene ether, A step of setting the polymerization time to obtain the target weight-average molecular weight polyphenylene ether, During the polymerization time, the process includes the oxidative polymerization step described above, It is preferable that the weight-average molecular weight of the polyphenylene ether obtained during the polymerization time is within ±5% of the target weight-average molecular weight.

[0067] The target average molecular weight of the resulting polyphenylene ether is not particularly limited, as long as the reduced viscosity (ηsp / c) of the polyphenylene ether, measured in a 0.5 g / dL chloroform solution at 30°C, is in the range of 0.03 to 0.30 dL / g. The weight-average molecular weight of the polyphenylene ether obtained at the aforementioned polymerization time can be measured by the method described in the examples.

[0068] Furthermore, the manufacturing method in this embodiment is A step to set the target weight-average molecular weight of the resulting polyphenylene ether, The process includes obtaining a polyphenylene ether with the target weight-average molecular weight through the oxidative polymerization process described above, It is preferable that the polymerization time required to polymerize the polyphenylene ether having the target weight-average molecular weight is within ±5% of the average polymerization time.

[0069] In general, with polyphenylene ethers using 2,6-dimethylphenol, it is known that increasing the solid content concentration in the reaction solution can shorten the reaction time to reach the desired molecular weight. However, in the case of phenols having a hydrogen atom in the ortho position, when the solid content concentration in the reaction solution rises above a certain level, the reaction starting from the ortho position (the reaction that generates the structure represented by formula (11) above) becomes active, making molecular weight control extremely difficult. In this embodiment, even when using phenols having a hydrogen atom in the ortho position, variations in polymerization reaction activity can be suppressed by adjusting the reaction vessel, the condenser installed therein, and the polymerization reaction conditions to an appropriate range, and as a result, the polyphenylene ether of this embodiment can be produced stably.

[0070] Furthermore, it is generally known that the volatility (ease of droplet entrainment) of organic solvents correlates with their surface tension. For example, organic solvents with low surface tension volatilize easily because their cohesive force on the liquid surface is weak, while organic solvents with high surface tension volatilize less easily because their cohesive force on the liquid surface is strong. Therefore, in the method for producing polyphenylene ether according to this embodiment, the polymerization is oxidative polymerization using the phenol of formula (1) and the phenol of formula (2) described above, and the polarity state and surface tension of the reaction solution including the raw materials, solvent and catalyst are different from those of general oxidative polymerization using 2,6-dimethylphenol. It is presumed that the above-mentioned effects are achieved because the refrigerant temperature of the cooler attached to the reaction vessel during oxidative polymerization is adjusted to the above range, the ratio of the reaction vessel volume to the cooler surface area is designed to be within the above range, and / or the ratio of the polymerization reaction solution volume to the amount of oxygen-containing gas permeation is adjusted to the above range, thereby appropriately condensing the organic solvent entrained in the vent gas and appropriately controlling the amount of organic solvent entrained in droplets.

[0071] The temperature of the oxidative polymerization 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.

[0072] In the method for producing polyphenylene ether, polymerization can also be carried out in a poor solvent such as an alcohol.

[0073] Furthermore, in the method for producing polyphenylene ether according to 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 also 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.

[0074] In the method for producing polyphenylene ether according to this embodiment, water may be added to extract the compound from which the copper catalyst has been deactivated, and after liquid-liquid separation into an organic phase and an aqueous phase, the copper catalyst may 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.

[0075] 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.

[0076] The method for volatilizing the solvent contained in the organic phase is not particularly limited, but examples include transferring the organic phase to a high-temperature concentration tank and concentrating it by distilling off the solvent, or concentrating it by distilling off toluene using equipment such as a rotary evaporator.

[0077] 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.

[0078] To obtain the aforementioned polyphenylene ether with high efficiency, methods such as increasing the drying temperature, increasing the vacuum level in the drying atmosphere, and stirring during drying are effective, but increasing the drying temperature is particularly preferred 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. [Examples]

[0079] The embodiment will be described in more detail below based on the following examples, but this embodiment is not limited to the following examples.

[0080] (Production of polyphenylene ether) • Example 1 The polymerization tank is equipped with a sparger, stirring turbine blades, and baffles at the bottom for introducing oxygen-containing gas, and a vent gas line at the top of the polymerization tank circulates brine at -10°C with a surface area of ​​13m 2 A reflux condenser was installed, and polymerization was carried out using a 1,300-liter jacketed polymerization tank. Nitrogen gas was blown into the polymerization tank at a flow rate of 1,320 L / min, while adding 0.11 kg of cupric oxide, 0.80 kg of 47% by mass aqueous solution of hydrogen bromide, 0.26 kg of di-tert-butylethylenediamine, 1.2 kg of di-n-butylamine, 3.8 kg of butyldimethylamine, 390 kg of toluene, and 0.060 kg of trioctylmethylammonium chloride (R=C8- 10) was added to make a homogeneous solution. Next, using a pump, 11 kg of 2-tert-butyl-5-methylphenol, 74 kg of 2,6-dimethylphenol, and 86 kg of toluene dropwise solution were added to the polymerization tank over 35 minutes. Simultaneously, air was introduced into the polymerization solution from the bottom of the polymerization tank at a rate of 900 L / min via a sparger, and polymerization was started. Air was aerated for a predetermined time to obtain the polymerization mixture. During polymerization, the internal temperature was controlled to 40°C. At the end of polymerization, the polymerization mixture (polymerization solution) was in a homogeneous solution state. After that, the aeration of dry air was stopped, and 1.1 kg of tetrasodium ethylenediaminetetraacetate (reagent manufactured by Dojin Chemical Research Institute) was added to the polymerization mixture as an aqueous solution in 57 kg of water. The polymerization mixture was stirred at 70°C for 240 minutes, then allowed to stand for 30 minutes, and the organic phase and aqueous phase were separated by liquid-liquid separation.

[0081] • Example 2 The procedure was carried out in the same manner as in Example 1, except that a dropwise solution of 16 kg of 2-tert-butyl-5-methylphenol, 69 kg of 2,6-dimethylphenol, and 86 kg of toluene was added to the polymerization vessel over 35 minutes using a pump, to obtain polyphenylene ether.

[0082] • Example 3 The procedure was carried out in the same manner as in Example 1, except that 22 kg of 2-tert-butyl-5-methylphenol, 64 kg of 2,6-dimethylphenol, and 86 kg of toluene dropwise solution were added to the polymerization vessel over 35 minutes using a pump, to obtain polyphenylene ether.

[0083] • Example 4 The surface area of ​​the reflux condenser attached to the vent gas line at the top of the polymerization tank is 0.43 m. 2 Except for the change, the procedure was carried out in the same manner as in Example 3 to obtain polyphenylene ether.

[0084] • Example 5 Except for changing the temperature of the brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank to 15°C, the procedure was carried out in the same manner as in Example 3 to obtain polyphenylene ether.

[0085] • Example 6 Except for changing the temperature of the brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank to -20°C, the procedure was carried out in the same manner as in Example 3 to obtain polyphenylene ether.

[0086] • Example 7 The procedure was carried out in the same manner as in Example 1, except that a dropwise solution of 31 kg of 2-tert-butyl-5-methylphenol, 54 kg of 2,6-dimethylphenol, and 86 kg of toluene was added to the polymerization vessel over 35 minutes using a pump, to obtain polyphenylene ether.

[0087] • Example 8 The brine circulating through the reflux condenser attached to the vent gas line at the top of the polymerization tank is circulated at 25°C, and the surface area of ​​the reflux condenser is 0.32 m. 2 Except for the change, the procedure was carried out in the same manner as in Example 3 to obtain polyphenylene ether.

[0088] • Example 9 The brine circulating through the reflux condenser attached to the vent gas line at the top of the polymerization tank is kept at -20°C, and the surface area of ​​the reflux condenser is 0.32 m. 2 Except for the change, the procedure was carried out in the same manner as in Example 3 to obtain polyphenylene ether.

[0089] • Example 10 Except for changing the temperature of the brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank to 25°C, the procedure was carried out in the same manner as in Example 3 to obtain polyphenylene ether.

[0090] • Example 11 The temperature of the brine circulating through the reflux condenser attached to the vent gas line at the top of the polymerization tank is set to 5°C, and the surface area of ​​the reflux condenser is set to 0.52 m. 2 Except for the change, the procedure was carried out in the same manner as in Example 1 to obtain polyphenylene ether.

[0091] • Example 12 The temperature of the brine circulating through the reflux condenser attached to the vent gas line at the top of the polymerization tank is set to 5°C, and the surface area of ​​the reflux condenser is set to 0.32 m. 2 Except for the change, the procedure was carried out in the same manner as in Example 1 to obtain polyphenylene ether.

[0092] • Example 13 The brine circulating through the reflux condenser attached to the vent gas line at the top of the polymerization tank is circulated at 25°C, and the surface area of ​​the reflux condenser is 0.52 m. 2 Except for the change, the procedure was carried out in the same manner as in Example 3 to obtain polyphenylene ether.

[0093] • Example 14 Except for changing the target molecular weight to achieve the viscosity shown in the table, the procedure was carried out in the same manner as in Example 7 to obtain polyphenylene ether.

[0094] • Comparative Example 1 The surface area of ​​the reflux condenser attached to the vent gas line at the top of the polymerization tank is 0.22 m. 2 Except for the change, the procedure was carried out in the same manner as in Example 3 to obtain polyphenylene ether.

[0095] • Comparative Example 2 Except for changing the temperature of the brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank to 35°C, the procedure was carried out in the same manner as in Example 1 to obtain polyphenylene ether.

[0096] • Comparative Example 3 The brine temperature circulating through the reflux condenser attached to the vent gas line at the top of the polymerization tank is set to 25°C, and the surface area of ​​the reflux condenser is set to 0.22 m. 2 Except for the change, the procedure was carried out in the same manner as in Example 3 to obtain polyphenylene ether.

[0097] ·Reference example 1 The procedure was carried out in the same manner as in Example 1, except that 2-tert-butyl-5-methylphenol was not used, and instead a dropwise solution of 86 kg of 2,6-dimethylphenol and 86 kg of toluene was used to obtain polyphenylene ether.

[0098] ·Reference example 2 Except for changing the temperature of the brine circulating in the reflux condenser attached to the vent gas line at the top of the polymerization tank to 25°C, the procedure was carried out in the same manner as in Reference Example 1 to obtain polyphenylene ether.

[0099] ·Reference example 3 The surface of the reflux condenser installed in the vent gas line at the top of the polymerization tank is 0.22 m 2 Aside from the change, the procedure was carried out in the same manner as in Reference Example 1 to obtain polyphenylene ether.

[0100] ·Reference example 4 Except for changing the temperature of the brine circulating in the reflux condenser attached to the vent gas line at the top of the polymerization tank to 35°C, the procedure was carried out in the same manner as in Reference Example 1 to obtain polyphenylene ether.

[0101] • Example 15 The polymerization tank is equipped with a sparger, stirring turbine blades, and baffles at the bottom for introducing oxygen-containing gas, and a vent gas line at the top of the polymerization tank circulates brine at -10°C with a surface area of ​​13m 2 A reflux condenser was installed, and polymerization was carried out using a 1,300-liter jacketed polymerization tank. Nitrogen gas was blown into the polymerization tank at a flow rate of 1,300 L / min, while adding 0.11 kg of cupric oxide, 0.80 kg of 47% by mass aqueous solution of hydrogen bromide, 0.26 kg of di-tert-butylethylenediamine, 1.2 kg of di-n-butylamine, 3.8 kg of butyldimethylamine, 390 kg of toluene, and 0.060 kg of trioctylmethylammonium chloride (R=C8- 10Next, a homogeneous solution was prepared by adding the following: Next, using a pump, 11 kg of 2-tert-butyl-5-methylphenol, 74 kg of 2,6-dimethylphenol, and 86 kg of toluene were added dropwise to the polymerization tank over a period of 35 minutes. Simultaneously, air was introduced into the polymerization solution from the bottom of the polymerization tank at a rate of 900 L / min via a sparger, and polymerization was started. Specifically, air was passed through 650 L of polymerization reaction solution for a predetermined time to obtain a polymerization mixture. During polymerization, the internal temperature was controlled to 40°C. At the end of polymerization, the polymerization mixture (polymerization solution) was in a homogeneous solution state. Subsequently, the flow of dry air was stopped, and 1.2 kg of tetrasodium ethylenediaminetetraacetate (reagent manufactured by Dojin Chemical Laboratories) was added to the polymerization mixture as an aqueous solution in 57 kg of water. The polymerization mixture was stirred at 70°C for 240 minutes, then allowed to stand for 30 minutes, and the organic phase and aqueous phase were separated by liquid-liquid separation.

[0102] • Example 16 The procedure was carried out in the same manner as in Example 15, except that 16 kg of 2-tert-butyl-5-methylphenol, 69 kg of 2,6-dimethylphenol, and 86 kg of toluene dropwise solution were added to the polymerization vessel over 35 minutes using a pump, to obtain polyphenylene ether.

[0103] • Example 17 The procedure was carried out in the same manner as in Example 15, except that 22 kg of 2-tert-butyl-5-methylphenol, 64 kg of 2,6-dimethylphenol, and 86 kg of toluene dropwise solution were added to the polymerization vessel over 35 minutes using a pump, to obtain polyphenylene ether.

[0104] • Example 18 The polymerization was started by blowing nitrogen gas into the polymerization tank at a flow rate of 246 L / min and introducing air into the polymerization solution from the bottom of the polymerization tank at a rate of 167 L / min via a sparger, and the operation was carried out in the same manner as in Example 17 to obtain polyphenylene ether.

[0105] • Example 19 Except for changing the temperature of the brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank to 15°C, the procedure was carried out in the same manner as in Example 17 to obtain polyphenylene ether.

[0106] • Example 20 Except for changing the temperature of the brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank to -20°C, the procedure was carried out in the same manner as in Example 17 to obtain polyphenylene ether.

[0107] • Example 21 The procedure was carried out in the same manner as in Example 15, except that a dropwise solution of 31 kg of 2-tert-butyl-5-methylphenol, 54 kg of 2,6-dimethylphenol, and 86 kg of toluene was added to the polymerization vessel over 35 minutes using a pump, to obtain polyphenylene ether.

[0108] • Example 22 The brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank was set to 25°C. Nitrogen gas was blown into the polymerization tank at a flow rate of 387 L / min, and air was introduced into the polymerization solution from the bottom of the polymerization tank at a rate of 263 L / min via a sparger to start polymerization. The operation was carried out in the same manner as in Example 17, except that polymerization was started.

[0109] • Example 23 The polymerization was started by blowing nitrogen gas into the polymerization tank at a flow rate of 173 L / min and introducing air into the polymerization solution from the bottom of the polymerization tank at a rate of 117 L / min via a sparger, thereby initiating polymerization. The rest of the procedure was carried out in the same manner as in Example 17 to obtain polyphenylene ether.

[0110] • Example 24 The brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank was kept at 15°C, nitrogen gas was blown into the polymerization tank at a flow rate of 244 L / min, and air was introduced into the polymerization solution from the bottom of the polymerization tank at a rate of 166 L / min via a sparger to start polymerization. The operation was carried out in the same manner as in Example 15, except that the brine temperature was set to 15°C, and nitrogen gas was blown into the polymerization tank at a flow rate of 244 L / min to start polymerization.

[0111] • Example 25 The brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank was set to 20°C. Nitrogen gas was blown into the polymerization tank at a flow rate of 179 L / min, and air was introduced into the polymerization solution from the bottom of the polymerization tank at a rate of 121 L / min via a sparger to start polymerization. The operation was carried out in the same manner as in Example 17, except that polymerization was started.

[0112] • Example 26 The brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank was set to 0°C. Nitrogen gas was blown into the polymerization tank at a flow rate of 387 L / min, and air was introduced into the polymerization solution from the bottom of the polymerization tank at a rate of 263 L / min via a sparger to start polymerization. The operation was carried out in the same manner as in Example 15, except that polymerization was started.

[0113] • Example 27 The brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank was set to 25°C. Nitrogen gas was blown into the polymerization tank at a flow rate of 1310 L / min, and air was introduced into the polymerization solution from the bottom of the polymerization tank at a rate of 890 L / min via a sparger to start polymerization. The procedure was carried out in the same manner as in Example 17, except that polymerization was started.

[0114] • Example 28 Except for changing the target molecular weight to achieve the viscosity shown in the table, the procedure was carried out in the same manner as in Example 21 to obtain polyphenylene ether.

[0115] • Comparative Example 4 The polymerization was started by blowing nitrogen gas into the polymerization tank at a flow rate of 7740 L / min and introducing air into the polymerization solution from the bottom of the polymerization tank at a rate of 5260 L / min via a sparger, and the operation was carried out in the same manner as in Example 17 to obtain polyphenylene ether.

[0116] Comparison Example 5 The polymerization was started by blowing nitrogen gas into the polymerization tank at a flow rate of 131 L / min and introducing air into the polymerization solution from the bottom of the polymerization tank at a rate of 89 L / min via a sparger, and the process was carried out in the same manner as in Example 17 to obtain polyphenylene ether.

[0117] • Comparative Example 6 The brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank was set to 35°C. Nitrogen gas was blown into the polymerization tank at a flow rate of 244 L / min, and air was introduced into the polymerization solution from the bottom of the polymerization tank at a rate of 166 L / min via a sparger to start polymerization. The operation was carried out in the same manner as in Example 15, except that polymerization was started.

[0118] ·Reference example 5 The procedure was carried out in the same manner as in Example 15, except that 2-tert-butyl-5-methylphenol was not used, and instead a dropwise solution of 86 kg of 2,6-dimethylphenol and 86 kg of toluene was used to obtain polyphenylene ether.

[0119] ·Reference example 6 The brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank was kept at 25°C. Nitrogen gas was blown into the polymerization tank at a flow rate of 774 L / min, and air was introduced into the polymerization solution from the bottom of the polymerization tank at a rate of 526 L / min via a sparger to start polymerization. Otherwise, the procedure was carried out in the same manner as in Reference Example 5 to obtain polyphenylene ether.

[0120] ·Reference example 7 Polyphenylene ether was obtained by proceeding in the same manner as in Reference Example 5, except that nitrogen gas was blown into the polymerization tank at a flow rate of 149 L / min, and air was introduced from the bottom of the polymerization tank through a sparger at a rate of 101 L / min of polymerization solution to start polymerization.

[0121] ·Reference example 8 Except for changing the temperature of the brine circulating in a reflux condenser attached to the vent gas line at the top of the polymerization tank to 35°C, the procedure was carried out in the same manner as in Reference Example 6 to obtain polyphenylene ether.

[0122] (Analysis of polyphenylene ethers) (1) Percentage change in solid content (%) The reaction solution after polymerization was collected in an aluminum dish and dried in a vacuum dryer at 130°C for 2 hours. The solid content concentration after polymerization was then calculated from the weight before and after drying using the following formula (11). Solid content concentration (wt%) = Weight of solid content after drying (g) / Weight of polymerization solution before drying (g) × 100 ... (11) Then, the percentage change between the solid content concentration of the monomer raw material before polymerization began, which was placed in the polymerization tank, and the solid content concentration after polymerization, which was derived from the above formula, was calculated using the following formula (12). The calculation results are shown in Tables 1 and 2. Change in solid content concentration (%) = Solid content concentration (wt%) / Raw material monomer concentration (wt%) ... (12)

[0123] (2) Reduced viscosity (ηsp / c) Polyphenylene ether with a weight-average molecular weight (Mw) that reached the target value was prepared in a 0.5 g / dL chloroform solution, and the reduced viscosity (ηsp / c) (dL / g) at 30°C was measured using an Ubbelohde viscous tube. The measurement results are shown in Tables 1 and 2.

[0124] (3) Weight-average molecular weight (Mw) of polyphenylene ether As the measuring instrument, a gel permeation chromatography (LC-2030C Plus, manufactured by Shimadzu Corporation) was used to create a calibration curve using standard polystyrene and ethylbenzene. Using this calibration curve, the number-average molecular weight (Mw) of the obtained polyphenylene ethers was measured. 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, 550, and 106. The column used consisted of two Showa Denko K.K. 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 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 weight-average molecular weight (Mw) was calculated from the percentage of peak area based on the molecular weight distribution curve obtained by GPC.

[0125] (4) Time to reach target molecular weight Following the procedures of Examples 1-28, Comparative Examples 1-6, and Reference Examples 1-8, solutions were sampled during the reaction while oxidative polymerization was carried out, and gel permeation chromatography measurements were performed. The start of polymerization was defined as the point at which air was introduced, and the time at which the weight-average molecular weight (Mw) of polyphenylene ether reached the target value was defined as the time to reach the target molecular weight (min). The measurement results are shown in Tables 1 and 2. In Examples 14 and 28, the target value for the weight-average molecular weight was set to 2,500, while in all other examples, it was set to 30,000.

[0126] (5) Variation in the time to reach the target molecular weight Oxidative polymerization was performed five times according to the procedures of Examples 1-10, Comparative Examples 1-5, and Reference Examples 1-6. The average of the time (min) to reach the target molecular weight for each of the five trials was calculated, and the results were evaluated according to the following criteria. The evaluation results are shown in Tables 1 and 2. ○: All target molecular weight attainment times (min) obtained from five oxidative polymerization cycles fall within ±5% of their average value. △: Four out of the target molecular weight attainment times (min) obtained from five oxidative polymerization cycles fall within ±5% of the average value. ×: Of the target molecular weight attainment times (min) obtained from five oxidative polymerization cycles, three or fewer fall within ±5% of the average value. (6) Variation in the weight-average molecular weight of the obtained polyphenylene ethers The target value for the weight-average molecular weight was set to 30,000, and the time it took to reach the target molecular weight, as measured in (4) above, was defined as the polymerization time. Following the procedures of Examples 1 to 10, Comparative Examples 1 to 5, and Reference Examples 1 to 6, the same oxidative polymerization was performed five times during the polymerization time. The average weight-average molecular weight of the five types of polyphenylene ethers obtained from the five oxidative polymerizations was calculated, and the results were evaluated according to the following criteria. The evaluation results are shown in Tables 1 and 2. ○: All weight-average molecular weights of the polyphenylene ethers obtained as a result of five oxidative polymerization steps fall within ±5% of their average value. △: Four of the weight-average molecular weights of the polyphenylene ethers obtained as a result of five oxidative polymerization steps fall within ±5% of the average value. ×: Three or fewer of the weight-average molecular weights of the polyphenylene ethers obtained as a result of five oxidative polymerization steps fall within ±5% of the average value.

[0127] [Table 1] [Table 2]

[0128] As shown in Tables 1 and 2, the polyphenylene ether production method of the examples allows for control of the change in solid content concentration of the polymerization solution at the end of the reaction within an appropriate range, resulting in stable polymerization activity and reduced variability in the time to reach the target molecular weight. Furthermore, the polyphenylene ether production methods in the reference examples all exhibited relatively stable polymerization activity regardless of the condenser and polymerization conditions, and variations in the time to reach the target molecular weight were also suppressed. [Industrial applicability]

[0129] The present invention provides a method for producing polyphenylene ether that enables the stable production of low-viscosity polyphenylene ether, and therefore has industrial value as a method for producing polyphenylene ether.

Claims

1. The process includes a step of introducing an oxygen-containing gas into a solution containing phenol of formula (1) and phenol of formula (2) below to carry out oxidative polymerization, 【Chemistry 1】 (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, 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. 【Chemistry 2】 (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 formula (3). 【Transformation 3】 (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. 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.) A vent gas cooler is provided at the top of the polymerization tank in which the oxidative polymerization is carried out. The relationship between the oxidation polymerization reaction temperature Tp and the refrigerant temperature Tc of the vent gas cooler satisfies the following equation (4): 10°C ≤ Tp - Tc ≤ 70°C ... (4) Volume Vm of the reaction vessel in which the oxidative polymerization is carried out. ３ and the surface Am of the vent gas cooler ２ The relationship satisfies equation (5) below, 0.05 ≤ V / A ≤ 5.0 ... (5) A method for producing polyphenylene ether, characterized in that the reduced viscosity (ηsp / c) of the obtained polyphenylene ether, measured with a chloroform solution of 0.5 g / dL concentration at 30°C, is 0.03 to 0.30 dL / g.

2. The oxidation polymerization reaction temperature Tp, the refrigerant temperature Tc of the vent gas cooler, and the volume Vm of the reaction vessel where the oxidation polymerization is carried out. ３ and the surface Am of the vent gas cooler ２ A method for producing polyphenylene ether according to claim 1, characterized in that the relationship satisfies the following formula (6). 10≦(Tp-Tc)A / V≦700...(6)

3. The process includes a step of introducing an oxygen-containing gas into a solution containing phenol of formula (1) and phenol of formula (2) below to carry out oxidative polymerization, 【Chemistry 4】 (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, 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. 【Transformation 5】 (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 formula (3). 【Transformation 6】 (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.) A vent gas cooler is provided at the top of the polymerization tank in which the oxidative polymerization is carried out. The relationship between the oxidation polymerization reaction temperature Tp and the refrigerant temperature Tc of the vent gas cooler satisfies the following equation (4): 10°C ≤ Tp - Tc ≤ 70°C ... (4) Volume LVm of the oxidative polymerization reaction solution ３ and the permeability of the oxygen-containing gas FVm ３ The relationship / min satisfies the following equation (7), 0.15 ≤ LV / FV ≤ 2.5 ... (7) A method for producing polyphenylene ether, characterized in that the reduced viscosity (ηsp / c) of the obtained polyphenylene ether, measured with a chloroform solution of 0.5 g / dL concentration at 30°C, is 0.03 to 0.30 dL / g.

4. The oxidation polymerization reaction temperature Tp, the refrigerant temperature Tc of the vent gas cooler, and the volume LVm of the oxidation polymerization reaction solution. ３ and the permeability of the oxygen-containing gas FVm ３ A method for producing polyphenylene ether according to claim 3, wherein the relationship / min satisfies the following formula (8). 25≦(Tp-Tc)FV / LV≦470...(8)

5. A method for producing polyphenylene ether according to claim 1 or 3, characterized in that, with respect to a total of 100 mol% of the phenols of formula (1) and formula (2), the content ratio of the phenol of formula (1) is 70 mol% or more and less than 85 mol%, and the content of the phenol of formula (2) is more than 15 mol% and 30 mol% or less.

6. The phenol compound of formula (1) is 2,6-dimethylphenol, 2-methyl-6-ethylphenol, 2,6-diethylphenol, 2-ethyl-6-n-propylphenol, 2-methyl-6-chlorophenol, 2-methyl-6-bromophenol, 2-methyl-6-n-propylphenol, 2-ethyl-6-bromophenol, 2-methyl-6-n-butylphenol, 2,6-di-n-propylphenol, 2-ethyl-6-chlorophenol, 2-methyl-6-phenylphenol, 2 A method for producing polyphenylene ether according to claim 1 or 3, characterized in that it is one or more selected from the group consisting of ,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.

7. A method for producing a polyphenylene ether according to claim 1 or 3, characterized in that the phenol compound of formula (2) is one or more selected from the group consisting of 2-isopropyl-5-methylphenol, 2-cyclohexyl-5-methylphenol, 2-tert-butyl-5-methylphenol, and 2-isobutyl-5-methylphenol.

8. A method for producing a polyphenylene ether according to claim 1 or 3, characterized in that the substructure represented by formula (3) is a t-butyl group.

9. Furthermore, the method for producing polyphenylene ether according to claim 1 or 3, characterized in that it further contains a phenol of the following formula (12). 【Transformation 7】 (In equation (12), 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 k is an integer from 1 to 4, independently of the others.

10. The phenol in formula (12) above is A phenol compound having two phenol units in its molecule, selected from the group consisting of 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4,4'-methylenebis(2,6-dimethylphenol), bis(4-hydroxy-3-methylphenyl)sulfide, bis(4-hydroxy-3,5-dimethylphenyl)sulfone, α,α'-bis(4-hydroxy-3,5-dimethylphenyl)-1,4-diisopropylbenzene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, and 1,1-bis(2-methyl-4-hydroxy-5-t-butylphenyl)butane; or; 4,4'-[(3-hydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(3-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 4,4'-[(4-hydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(4-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 4,4'-[(2-hydroxy-3-methoxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(4-hydroxy-3-ethoxy [Phenyl)methylene]bis(2,3,6-trimethylethylphenol), 4,4'-[(3,4-dihydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4'-[(3,4-dihydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 2,2'-[(4-hydroxyphenyl)methylene]bis(3,5,6-trimethylphenol), 4,4'-[4-(4-hydroxyphenyl)cyclohexylidene]bis(2,6-dimethylphenol), 4,4'-[(2-hydroxyphenyl)methylene] -Bis(2,3,6-trimethylphenol), 4,4'-[1-[4-[1-(4-hydroxy-3,5-dimethylphenyl)-1-methylethyl]phenyl]ethylidene]bis(2,6-dimethylphenol), 4,4'-[1-[4-[1-(4-hydroxy-3-fluorophenyl)-1-methylethyl]phenyl]ethylidene]bis(2,6-dimethylphenol), 2,6-bis[(4-hydroxy-3,5-dimethylphenyl)ethyl]-4-methylphenol, 2,6-bis[(4-hydroxy-2,3,6-trimethylphenyl] [(4-hydroxy-3,5,6-trimethylphenyl)methyl]-4-methylphenol, 2,6-bis[(4-hydroxy-3-methylphenyl)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- ris[(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'- Chilenbis[4-[(4-hydroxy-3,5-dimethylphenyl)methyl]-1,2,3-benzenetriol], 4,4'-cyclohexylidenebis[2-cyclohexyl-6-[(2-hydroxy-5-methylphenyl)methyl]phenol], 4,4'-cyclohexylidenebis[2-cyclohexyl-6-[(4-hydroxy-3,5-dimethylphenyl)methyl]phenol], 4,4'-cyclohexylidenebis[2-cyclohexyl-6-[(4-hydroxy-2-methyl-5-cyclohexylphenyl)methyl]phenol], 4,A method for producing polyphenylene ether according to claim 1 or 3, characterized in that the compound is a phenol compound having three or more phenol units in the molecule, selected from the group consisting of 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.

11. A method for producing a polyphenylene ether according to claim 1 or 3, characterized in that the molecular weight distribution (Mw / Mn) of the polyphenylene ether determined by gel permeation chromatography (GPC) is 2.0 to 6.

0.

12. A step to set the target weight-average molecular weight of the resulting polyphenylene ether, A step of setting the polymerization time to obtain the target weight-average molecular weight polyphenylene ether, and The process includes oxidative polymerization during the aforementioned polymerization time, The polyphenylene ether obtained during the aforementioned polymerization time is characterized in that the weight-average molecular weight is within ±5% of the target weight-average molecular weight. A method for producing polyphenylene ether according to claim 1 or 3.

13. A step to set the target weight-average molecular weight of the resulting polyphenylene ether, The process includes obtaining a polyphenylene ether with the target weight-average molecular weight through the oxidative polymerization step, A method for producing a polyphenylene ether according to claim 1 or 3, characterized in that the polymerization time required to polymerize the polyphenylene ether having the target weight-average molecular weight is within ±5% of the average polymerization time.

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