JP2013256647A - Method for producing polyphenylene ether powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain polyphenylene ether powders having proper pulverization rate, having less solvent to be used, capable of obtaining a molded body having practically sufficient strength and capable of inhibiting generation of fine powders after re-pulverization.SOLUTION: A production method for polyphenylene ether powders includes a precipitation step of adding a polymer solution obtained by polymerizing a phenol compound, and a poor solvent into a precipitation tank to precipitate polyphenylene ether. In the polymer solution to be added to the precipitation tank, X and Y satisfy the following formulas (I): 30<X≤48; and (II): Y≤min{0.45, 13.252×(X/100)-0.8725×(X/100)-0.5196} (wherein X is the concentration of [mass%] of polyphenylene ether in a good solvent solution; Y is the mass ratio (poor solvent/good solvent) of the poor solvent added to the precipitation tank in the precipitation step to the good solvent in the polymer solution; and Y≤min{a, b} means that Y is a smaller value or less of either a or b).

Description

  The present invention relates to a method for producing a polyphenylene ether powder.

  Conventionally, modified polyphenylene ether resin using polyphenylene ether as a raw material can produce products / parts of a desired shape by a molding method such as a melt injection molding method or a melt extrusion molding method. It is widely used as a material for products and parts in various industrial material fields.

  As a method for producing polyphenylene ether, a method is known in which phenols are oxidatively polymerized in a good solvent of polyphenylene ether in the presence of a copper compound and amines. As a method of precipitating polyphenylene ether from the polyphenylene ether solution obtained by this method, a method of precipitating polyphenylene ether particles by adding a poor solvent of polyphenylene ether such as methanol to a good solvent solution of polyphenylene ether is known. .

However, the polyphenylene ether particles obtained by the above-described method for depositing polyphenylene ether particles have a fine particle size and a large amount of fine powder. There is a problem that the biting into an extruder or the like is not stable.
To solve this problem, there is a method of granulating polyphenylene ether powder using a compactor or the like. However, ordinary polyphenylene ether has insufficient strength at the time of granulation, and again due to abrasion of the granulated material. There is a problem that fine powder is generated and the handleability is lowered.

  In addition, the particle size and the amount of fine powder of the polyphenylene ether particles are difficult to adjust because the particle size periodically varies in the precipitation step and further finely divided in the post-treatment step after the precipitation step. is there.

  Patent Document 1 describes a technique for obtaining a polyphenylene ether with a reciprocating stirrer that causes less fine powder scattering in the subsequent process and less biting into the extruder.

  Patent Document 2 describes a technique for precipitating particles having a uniform particle diameter using a draft tube type precipitation apparatus.

  Furthermore, in patent document 3, in order to suppress fine powder loss, filter clogging, and poor bite of the extruder, a proposal of a technique that regulates the stirring speed, the polymer concentration, the precipitation temperature, the amount of poor solvent, etc. during precipitation has been made. .

  Furthermore, Patent Document 4 proposes a method of compressing and granulating polyphenylene ether particles using a compactor or the like. Patent Document 4 describes a method for producing granular polyphenylene ether by regrinding a molded product obtained by compression granulation.

JP 2000-281773 A International Publication No. 2003/064499 US Patent Application Publication No. 2011/0160421 Japanese Patent No. 4152521

However, the technique described in Patent Document 1 has insufficient stability during the operation of the precipitation process, and the particle size is periodically changed to generate fine powder.
The technique described in Patent Document 2 is a precipitation technique in a region where the polymer concentration is low, and has a problem that the amount of solvent used increases and is inefficient. In addition, the particles obtained by this technique have a problem that the fine powder ratio is small and the particles are uniform, so that they are difficult to be compacted and high in bulk density.
The technique described in Patent Document 3 also has a problem that it includes precipitation in a region where the polymer concentration is low and is unstable and inefficient as a precipitation region.
With respect to the production method described in Patent Document 4, sufficient characteristics have not yet been obtained from the viewpoint of more strongly compression-molding polyphenylene ether and reliably suppressing the generation of fine powder even during pulverization.

As described above, the conventional method for producing polyphenylene ether has a problem that the fine powder rate cannot be controlled within an appropriate range in the post-treatment step after the precipitation step.
Further, in the prior art, since the polyphenylene ether powder is precipitated in a region where the polymer concentration is low, there is a problem that the amount of solvent used is large and the recovery cost is also great.
Thus, the particles deposited by the conventional precipitation method have a problem in handling, and when used as a compression molding raw material, the fine powder ratio is small and the amount of good solvent is greatly reduced by drying. There is also a problem that the strength of the molded body becomes insufficient and a large amount of fine powder is generated after re-grinding.
That is, it cannot fully meet the demands of the industry in terms of both handleability and compression granulation.

  Therefore, in the present invention, in view of the above-mentioned problems of the prior art, the fine powder rate can be appropriately controlled, the amount of solvent used is small, a practically sufficient strength is obtained in the compression molded product, and the molded product is reground. The object of the present invention is to provide a method for producing a polyphenylene ether powder capable of obtaining a polyphenylene ether powder capable of suppressing the generation of fine powder.

As a result of intensive studies in order to solve the above-described problems of the prior art, the inventors have made the concentration of the polymer solution added to the precipitation tank higher than that of the prior art, and set the ratio of the poor solvent and the good solvent to a predetermined value. By maintaining in the above range, it is finely granulated moderately in the post-treatment step after precipitation, that is, the fine granule rate is appropriately controlled, and the amount of good solvent suitable for granulation is maintained in the particles. The inventors have found that a polyphenylene ether powder that is extremely excellent in the formation of a body can be obtained, and the present invention has been completed.
That is, the present invention is as follows.

[1]
A polymerization step of polymerizing a phenol compound in a good solvent of polyphenylene ether to obtain a polymer solution;
Adding a polymer solvent and a poor solvent for polyphenylene ether to a precipitation tank, and depositing polyphenylene ether to form a slurry; and
Have
In the polymer solution added to the precipitation tank, the concentration of polyphenylene ether in a good solvent solution is X (mass%),
When the mass ratio (poor solvent / good solvent) of the poor solvent added to the precipitation tank and the good solvent in the polymer solution in the precipitation step is Y, the X and Y are represented by the following formula (I), A method for producing a polyphenylene ether powder that satisfies (II).
30 <X ≦ 48 (I)
Y ≦ min {0.45, 13.252 · (X / 100) ² −0.8725 · (X / 100) −0.5196} (II)
(In formula (II), Y ≦ min {a, b} means that Y is equal to or smaller than the smaller value of either a or b.)
[2]
After the said polymerization process, the polymer solution obtained by the said polymerization process is heated more than the boiling point of the good solvent of the said polyphenylene ether, and the concentration process which obtains the polymer solution which adjusted the polymer concentration is performed as described in said [1]. Of manufacturing polyphenylene ether powder.
[3]
[1] The method further comprising the step of washing the slurry produced by depositing the polyphenylene ether with a poor solvent, solid-liquid separation to obtain wet polyphenylene ether, and then mechanically crushing the wet polyphenylene ether. Or the manufacturing method of the polyphenylene ether powder as described in [2].
[4]
The method for producing a polyphenylene ether powder according to any one of the above [1] to [3], wherein the good solvent for the polyphenylene ether is at least one selected from the group consisting of benzene, toluene, and xylene.
[5]
The polyphenylene according to any one of [1] to [4], wherein the poor solvent of the polyphenylene ether is at least one selected from the group consisting of methanol, ethanol, isopropanol, n-butanol, acetone, methyl ethyl ketone, and water. A method for producing ether powder.
[6]
The method for producing a polyphenylene ether powder according to any one of [1] to [5], wherein the poor solvent for the polyphenylene ether contains 0.05 to 30% by mass of water in the poor solvent.
[7]
[1] to [1] to [3], wherein the precipitation tank is provided with at least one stirrer blade selected from the group consisting of an inclined paddle blade, a screw blade, and a ribbon blade, and is stirred by the stirrer blade in the precipitation step. [6] The method for producing a polyphenylene ether powder according to any one of [6].
[8]
The method for producing a polyphenylene ether powder according to any one of [1] to [7], wherein the precipitation tank is provided with at least one baffle.
[9]
The precipitation tank includes a draft tube, and the draft tube includes at least one stirrer blade selected from the group consisting of the inclined paddle blade, screw blade, and ribbon blade, and the stirring blade inside the draft tube The method for producing a polyphenylene ether powder according to [7] or [8], wherein a lower discharge blade is used and stirring is performed by the stirring blade in the precipitation step.
[10]
The precipitation tank further includes a stirring blade that is a ribbon blade on the outside of the draft tube, and the stirring blade outside the draft tube is an upper discharge blade. In the precipitation step, a ribbon outside the draft tube is used. The method for producing a polyphenylene ether powder according to [9], wherein stirring is performed with a stirring blade that is a blade.
[11]
The method for producing a polyphenylene ether powder according to any one of the above [1] to [10], wherein the liquid temperature in the precipitation step is 30 to 63 ° C.
[12]
The method for producing a polyphenylene ether powder according to any one of the above [1] to [11], wherein the residence time of the polyphenylene ether in the precipitation tank is 0.25 to 5 minutes.
[13]
After the precipitation step, further comprising a drying step,
The polyphenylene ether powder according to any one of [1] to [12] above, wherein a fine powder ratio (content ratio of particles having a particle size of 105 μm or less) of the polyphenylene ether powder after the drying step is 20% by mass or more. Production method.
[14]
The method for producing a polyphenylene ether powder according to any one of the above [1] to [13], wherein the amount of the good solvent contained in the polyphenylene ether powder after the drying step is more than 0.3% by mass.
[15]
The polyphenylene ether obtained by the method for producing a polyphenylene ether powder according to any one of the above [1] to [14] is compression molded to produce a molded body having a density of 0.7 to 1.06 g / cm ^3. ,
By re-grinding the molded body, a polyphenylene ether powder having a content of fine particles having a particle size of 105 μm or less of 0.5% by mass or less is obtained.
Production method of polyphenylene ether powder.
[16]
The polyphenylene according to the above [15], wherein the ratio of the polyphenylene ether powder having a particle size of 105 μm to 5 mm present in the polyphenylene ether powder obtained by re-pulverizing the molded body is 90% by mass or more. A method for producing ether powder.

  According to the method for producing a polyphenylene ether powder of the present invention, the fine powder rate can be appropriately controlled, the amount of solvent used is small, a practically sufficient strength is obtained in a compression molded product, and the molded product is reground. In addition, it is possible to produce a polyphenylene ether powder that can suppress the generation of fine powder.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

[Method for producing polyphenylene ether powder]
The method for producing the polyphenylene ether powder of the present embodiment is as follows:
A polymerization step of polymerizing a phenol compound in a good solvent of polyphenylene ether to obtain a polymer solution;
Thereafter, as an optional step, a concentration step for obtaining a polymer solution in which the polymer solution obtained in the polymerization step is heated to the boiling point of the good solvent or more to adjust the polymer solution concentration;
A polymer solution after the polymerization step, or a polymer solution after the concentration step, and a poor solvent for the polyphenylene ether are added to the precipitation tank, and the polyphenylene ether is precipitated to form a slurry; and
Have
In the polymer solution added to the precipitation tank, the concentration of polyphenylene ether in a good solvent solution is X (mass%),
When the mass ratio (poor solvent / good solvent (wt / wt)) of the poor solvent added to the precipitation tank and the good solvent in the polymer solution in the precipitation step is Y,
Said X and Y are the manufacturing method of the polyphenylene ether powder which satisfy | fills following formula (I), (II).
30 <X ≦ 48 (I)
Y ≦ min {0.45, 13.252 · (X / 100) ² −0.8725 · X / 100−0.5196} (II)
In formula (II), Y ≦ min {a, b} means that Y is equal to or smaller than the smaller value of either a or b.

The “concentration (mass%) of the polyphenylene ether in the good solvent solution” means the concentration of the polymer solution obtained in the polymerization step or the concentration step described above, and the good solvent charged in advance in the precipitation tank, The good solvent of the so-called initial charge liquid is not included in the conversion of the concentration.
The “poor solvent to be added to the precipitation tank in the precipitation step” used for the calculation of Y (poor solvent / good solvent) means that the initial charge to the precipitation tank is completed and then the polymer solution is added. It means a poor solvent added for precipitating polyphenylene ether, and does not include a poor solvent previously charged in the precipitation tank, that is, a poor solvent of a so-called initial charge liquid.
Furthermore, “good solvent in polymer solution” used for calculation of Y (poor solvent / good solvent) means a good solvent in the polymer solution obtained in the above-described polymerization step or concentration step. The liquid good solvent shall not be included.

(Polyphenylene ether (PPE))
In the polyphenylene ether powder production method of the present embodiment, a polyphenylene ether produced through a polymerization step described later, a concentration step performed as necessary, and a precipitation step (hereinafter sometimes simply referred to as “PPE”). This will be described below.

  In the polyphenylene ether powder production method of the present embodiment, the polyphenylene ether produced by the polymerization step is a homopolymer and / or copolymer having a repeating unit structure represented by the following formula (1).

(1)

In said formula (1), R < ₁ >, R < ₂ >, R < ₃ > and R < ₄ > are respectively independently a hydrogen atom, a halogen atom, a C1-C7 alkyl group, a phenyl group, a haloalkyl group, an aminoalkyl group. , A hydrocarbonoxy group, and a halohydrocarbonoxy group in which at least two carbon atoms separate a halogen atom and an oxygen atom.

In the formula (1), examples of the halogen atom represented by R ₁ , R ₂ , R ₃ , and R ₄ include a fluorine atom, a chlorine atom, a bromine atom, and the like, from the viewpoint that the polymerization reaction can be performed with high activity. , A chlorine atom and a bromine atom are preferable.

In the formula (1), the “alkyl group” represented by R ₁ , R ₂ , R ₃ , and R ₄ is preferably linear or branched having 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms. The chain alkyl group is not limited to the following, and examples thereof include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl and the like. From the viewpoint that the polymerization reaction can be performed with high activity, methyl and ethyl are preferable, and methyl is more preferable.

In the formula (1), the alkyl group represented by R ₁ , R ₂ , R ₃ , and R ₄ may be substituted with one or more substituents at substitutable positions.
Examples of such a substituent include, but are not limited to, for example, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom), an alkyl group having 1 to 6 carbon atoms (for example, methyl, ethyl, Propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl), aryl groups (eg, phenyl, naphthyl), alkenyl groups (eg, ethenyl, 1-propenyl, 2-propenyl), alkynyl groups ( For example, ethynyl, 1-propynyl, 2-propynyl), aralkyl group (for example, benzyl, phenethyl), alkoxy group (for example, methoxy, ethoxy) and the like can be mentioned.

  The loose apparent specific gravity of the polyphenylene ether is preferably 0.4 or more, more preferably 0.45 or more, and further preferably 0.48 or more. The upper limit of the loose apparent specific gravity is not particularly limited.

  The polyphenylene ether preferably has a solid apparent specific gravity of 0.55 or more, more preferably 0.6 or more, and even more preferably 0.65 or more. The upper limit of the apparent apparent specific gravity is not particularly limited, but is preferably 1.06 or less.

  By setting the looseness and the hardened apparent specific gravity within the above range, the compacted filler is excellent in compacting and granulating the polyphenylene ether powder, so that a strong granulated body tends to be obtained.

The loose apparent specific gravity can be measured by using a powder tester (manufactured by Hosokawa Micron Corporation: Powder Tester TYPE PT-E) according to its operation manual.
That is, (1) A fixed chute is fitted to two pins on the front surface of the casing, and a vibratory chute, a space ring, a sieve (mesh opening 710 μm), a fluoisae, and a sabae are attached to a vibration table in this order and fixed with a knob nut. (2) Place the rectangular bat directly under the fixed chute and place the apparent specific gravity measuring cup in the recess of the table / cup base. At this time, the center of the cup and the fixed chute are aligned (the cup empty mass is weighed in advance). (3) Gently put an appropriate amount of powder for measurement on a sieve using a scoop. (4) Set the vibration / tapping switch to VIB. Set to. Set the timer all the way to the right, check that the rheostat voltage is zero, and press the start button. (5) The voltage of the rheostat is gradually increased to allow the powder to flow out. The rheostat voltage is adjusted so that the time until the cup reaches the peak is about 20-30 seconds. When the cup is filled in a pile, the voltage of the rheostat is set to 0 and the vibration is stopped. (6) Stand the blade vertically and grind the side of the powder, and weigh the powder in the cup. (7) Since the content of the cup is 100 cc, the loose apparent specific gravity is calculated by the calculation of powder mass ÷ 100 and recorded.
Similarly, the apparent apparent specific gravity can be measured using a powder tester (manufactured by Hosokawa Micron Corporation: Powder Tester TYPE PT-E) according to its operation manual.
In other words, the cap attached to the apparent specific gravity measuring cup is added and placed in the tapping holder. Use a scoop to gently pour the powder up to the top of the cap. Before tapping, attach a cap cover on the cap to prevent the powder in the cup from splashing during tapping. Set the vibration / tapping switch to TAP. Set towards. Set the timer to 180 seconds (but 216 seconds for 50 cycles). Thereby, the number of tapping is set to 180 times. Press the start button. When tapping begins and the powder is compressed and the powder level is lowered to the top of the cup, stop tapping and remove the cap cover and add the powder. Stops automatically after tapping 180 times. When tapping is complete, remove the cup from the tapping holder and gently remove the cap and cap cover. Excess powder on top of the cup is ground with a blade. Thereafter, the mass of the powder is weighed with an upper pan balance in the same manner as the loose apparent specific gravity to determine the solid apparent specific gravity.

The reduced viscosity measured at 30 ° C. using a solution of 0.5 g of the polyphenylene ether in 1 dL of chloroform is preferably in the range of 0.15 to 1.0 dL / g, more preferably 0. It is in the range of 20 to 0.85 dL / g, more preferably in the range of 0.25 to 0.70 dL / g.
When the reduced viscosity is 0.15 dL / g or more, a polyphenylene ether powder having sufficient mechanical properties can be obtained.
Further, when the reduced viscosity is 1.0 dL / g or less, the solution viscosity at the time of polymerization does not become too high, the ability of the peripheral equipment of the polymerization tank can be appropriately controlled, post-processing is easy, and workability is improved. Will also be good.
The reduced viscosity can be measured by the method described in Examples described later.

Information relating to the molecular weight of the polyphenylene ether can be obtained by measurement using a gel permeation chromatography measuring apparatus.
As specific measurement conditions of gel permeation chromatography, Showa Denko Co., Ltd. Gel Permeation Chromatography System 21 (Column: Showa Denko K-805L in series, column temperature: 40 ° C., solvent : Chloroform, solvent flow rate: 1.0 ml / min, sample concentration: 1 g / L chloroform solution of polyphenylene ether), standard polystyrene (the molecular weight of standard polystyrene is 3,650,000, 2,170,000, 1 , 090,000, 681,000, 204,000, 52,000, 30,200, 13,800, 3,360, 1,300, 550) can be used to apply the measurement conditions. it can. The UV wavelength of the detector can be selected from 254 nm for standard polystyrene and 283 nm for polyphenylene ether.

  Further, as an index indicating the molecular weight distribution, a degree of dispersion represented by weight average molecular weight (Mw) / number average molecular weight (Mn) is used. The degree of dispersion indicates that the smaller the value is, the narrower the molecular weight distribution is, and 1 is the minimum value.

  The number average molecular weight (Mn) of the polyphenylene ether is preferably 7,000 or more and 35,000 or less. A more preferable lower limit is 8,000 or more, and a further preferable lower limit is 9,000 or more. Moreover, a more preferable upper limit is 30,000 or less, and a still more preferable upper limit is 25,000 or less.

  From the viewpoint of exhibiting sufficient mechanical properties in the polyphenylene ether powder, the lower limit of the number average molecular weight is preferably 7,000 or more, and from the viewpoint of liquid viscosity during the polymerization reaction, the upper limit of the number average molecular weight is 35, 000 or less is preferable.

The polyphenylene ether has a dispersity (Mw / Mn) of preferably 4.5 or less, more preferably 4.0 or less, still more preferably 3.75 or less, and even more preferably 3.5 or less. It is.
The degree of dispersion of the polyphenylene ether is preferably 1.6 or more, more preferably 1.8 or more, still more preferably 1.9 or more, and even more preferably 2.0 or more.
When the dispersity is in the above range, the low molecular weight component and the high molecular weight component are well balanced, and polyphenylene ether having such a dispersity tends to have an excellent balance between chemical resistance and fluidity.

The residual metal catalyst amount can be used as an indicator of the purity of the polyphenylene ether.
The polyphenylene ether preferably has a residual metal catalyst amount of less than 1.0 ppm. The amount of residual metal catalyst is preferably less than 1.0 ppm from the viewpoint of the purity of polyphenylene ether. Furthermore, when the amount of residual metal catalyst is less than 1.0 ppm, it tends to be able to suppress the yellowish color after the heat history. The amount of residual metal catalyst is more preferably less than 0.8 ppm, even more preferably less than 0.6 ppm, even more preferably less than 0.4 ppm, and particularly preferably less than 0.2 ppm.
The residual metal catalyst amount of polyphenylene ether can be measured with an atomic absorption photometer.

(Polyphenylene ether polymerization process)
In the polymerization step in the method for producing the polyphenylene ether powder of the present embodiment, the phenol compound is polymerized in a good solvent of polyphenylene ether to obtain a polymer solution of polyphenylene ether represented by the formula (1).
<Monomer used in polymerization step>
The polyphenylene ether represented by the above formula (1) can be produced by polymerizing the following phenol compounds.
Examples of the phenol compound include, but are not limited to, o-cresol, 2,6-dimethylphenol, 2-ethylphenol, 2-methyl-6-ethylphenol, 2,6-diethylphenol, 2 -N-propylphenol, 2-ethyl-6-n-propylphenol, 2-methyl-6-chlorophenol, 2-methyl-6-bromophenol, 2-methyl-6-isopropylphenol, 2-methyl-6- n-propylphenol, 2-ethyl-6-bromophenol, 2-methyl-6-n-butylphenol, 2,6-di-n-propylphenol, 2-ethyl-6-chlorophenol, 2-methyl-6 Phenylphenol, 2-phenylphenol, 2,6-diphenylphenol, 2,6-bis- (4-fur Rophenyl) phenol, 2-methyl-6-tolylphenol, 2,6-ditolylphenol, 2,5-dimethylphenol, 2,3,6-trimethylphenol, 2,5-diethylphenol, 2-methyl-5- Ethylphenol, 2-ethyl-5-methylphenol, 2-allyl-5-methylphenol, 2,5-diallylphenol, 2,3-diethyl-6-n-propylphenol, 2-methyl-5-chlorophenol, 2-methyl-5-bromophenol, 2-methyl-5-isopropylphenol, 2-methyl-5-n-propylphenol, 2-ethyl-5-bromophenol, 2-methyl-5-n-butylphenol, 2, 5-di-n-propylphenol, 2-ethyl-5-chlorophenol, 2-methyl-5-pheny Phenol, 2,5-diphenylphenol, 2,5-bis- (4-fluorophenyl) phenol, 2-methyl-5-tolylphenol, 2,5-ditolylphenol, 2,6-dimethyl-3-allylphenol 2,3,6-triallylphenol, 2,3,6-tributylphenol, 2,6-di-n-butyl-3-methylphenol, 2,6-di-t-butyl-3-methylphenol, 2, , 6-dimethyl-3-n-butylphenol, 2,6-dimethyl-3-t-butylphenol and the like.
In particular, from the viewpoint of being inexpensive and readily available, 2,6-dimethylphenol, 2,6-diethylphenol, 2,6-diphenylphenol, 2,3,6-trimethylphenol, 2,5-dimethylphenol 2,6-dimethylphenol and 2,3,6-trimethylphenol are more preferable.

The said phenol compound may be used independently or may be used in combination of 2 or more type.
For example, a method using a combination of 2,6-dimethylphenol and 2,6-diethylphenol, a method using a combination of 2,6-dimethylphenol and 2,6-diphenylphenol, Examples thereof include a method using a combination of trimethylphenol and 2,5-dimethylphenol, a method using a combination of 2,6-dimethylphenol and 2,3,6-trimethylphenol, and the like. The mixing ratio can be arbitrarily selected.
In addition, the phenol compounds used include a small amount of m-cresol, p-cresol, 2,4-dimethylphenol, 2,4,6-trimethylphenol, etc., which are contained as by-products during production. It may be.

As a monomer used for the polymerization step, a divalent phenol compound represented by the following formula (2) may be contained in addition to the phenol compound.
The divalent phenol compound represented by the following formula (2) is a reaction between a corresponding monovalent phenol compound and a ketone or a dihalogenated aliphatic hydrocarbon, or between corresponding monovalent phenol compounds. It can be advantageously produced industrially by reaction or the like.
For example, a compound group obtained by reaction of a monovalent phenol compound with a general-purpose ketone compound such as formaldehyde, acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, cyclohexane, or a compound group obtained by reaction of monovalent phenol compounds. Can be mentioned.
The divalent phenolic compound represented by the following formula (2) is not limited to the following, but for example, the following general formulas (2-a), (2-b), (2-c) The compound represented by these is mentioned.

... (2-a)

... (2-c)

Representative compounds represented by the above formula (2) are not limited to the following. For example, R ₅ and R ₆ are methyl groups, R ₇ and R ₈ are hydrogen, and X is both aryl. A compound in which R ₅ and R ₆ are methyl groups, R ₇ and R ₈ are hydrogen and X is methylene, R ₅ and R ₆ are methyl groups, R ₇ and R ₈ are hydrogen and X Wherein R ₅ , R ₆ and R ₇ are methyl groups, R ₈ is hydrogen and X is ethylene, R ₅ and R ₆ are methyl groups, R ₇ and R ₈ are hydrogen and X is isopropyl Ridene compound, R ₅ and R ₆ are methyl groups, R ₇ and R ₈ are hydrogen and X is cyclohexylidene, R ₅ , R ₆ and R ₇ are methyl groups, R ₈ is hydrogen and X is X A compound in which both aryl groups are directly connected, R ₅ , R ₆ and R ₇ are methyl A group wherein R ₈ is hydrogen and X is methylene, R ₅ , R ₆ and R ₇ are methyl groups, R ₈ is hydrogen and X is ethylene, R ₅ , R ₆ and R ₇ are methyl groups, A compound in which R ₈ is hydrogen and X is thio, R ₅ , R ₆ and R ₇ are methyl groups, R ₈ is hydrogen and X is isopropylidene, R ₅ , R ₆ , R ₇ and R ₈ are methyl A compound in which X is methylene, a compound in which R ₅ , R ₆ , R ₇ and R ₈ are methyl groups and X is ethylene, R ₅ , R ₆ , R ₇ and R ₈ are methyl groups and X is isopropylidene The compound etc. which are are mentioned.

  In the polymerization process of polyphenylene ether, a polyhydric phenol compound may coexist in addition to the above-described phenol compound and divalent phenol compound. The polyhydric phenol compound is not limited to the following. For example, the polyhydric phenol compound has 3 or more and less than 9 phenolic hydroxyl groups in the molecule, and 2, 6 of at least one phenolic hydroxyl group therein. And compounds having an alkyl group or an alkylene group at the position.

Specific examples of the polyhydric phenol compound are listed below.
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) ), 4,4 ′-[(2-hydroxy-3-methoxyphenyl) methylene] bis (2,6-dimethylphenol), 4,4 ′-[(4-hydroxy-3-ethoxyphenyl) methylene] bis ( 2,3,6-trimethylethylphenol), 4,4 ′-[(3,4-dihydroxyphenyl) methylene] bis (2,6-dimethylphenol), 4,4 ′-[(3,4-dihydroxyphenyl) ) Methylene] bis (2,3,6-to Limethylphenol), 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-methyl Phenol, 2,6-bis [(4-hydroxy Cis-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′-cyclohexylidenebis [2-cyclohexyl-6-[(2-hydroxy-5-methylphenyl) methyl] phenol], 4,4′-cyclohexylidenebis [2-cyclohexyl-6-[(4 -Hydroxy-3,5-dimethylphenyl) methyl] phenol], 4,4'-cyclohexylidenebis [2-cyclohexyl-6-[(4-hydroxy-2-methyl-5-cyclohexylphenyl) methyl] phenol] 4,4′-cyclohexylidenebis [2-cyclohexyl-6-[(2,3,4-trihydroxyphenyl) methyl] phenol], 4,4 ′, 4 ″, 4 ″ ′-(1,2 -Ethanediylidene) tetrakis (2,6-dimethylphenol), 4,4 ', 4 ", 4"'-(1,4-phenylenedimethylidene) tetrakis (2,6-dimethylphenol) However, it is not limited to these.

  The number of phenolic hydroxyl groups is not particularly limited as long as it is 3 or more. However, when the number is increased, it becomes difficult to control polymerization. The alkyl group or alkylene group at the 2,6-position is preferably a methyl group. Particularly preferred polyhydric phenol compounds are 4,4 ′-[(4-hydroxyphenyl) methylene] bis (2,6-dimethylphenol), 4,4 ′-[(3-hydroxyphenyl) methylene] bis (2, 6-dimethylphenol), 4,4 ′-[(4-hydroxyphenyl) methylene] bis (2,3,6-trimethylphenol), 4,4 ′-[(3-hydroxyphenyl) methylene] bis (2, 3,6-trimethylphenol), 4,4 ′, 4 ″, 4 ″ ′-(1,4-phenylenedimethylidene) tetrakis (2,6-dimethylphenol).

<Polymerization method>
In the method for producing a polyphenylene ether powder of the present embodiment, first, the above-described phenol compound is polymerized by solution polymerization to obtain a polymer solution containing polyphenylene ether (polymerization step).
In addition, the polymer solution obtained in the polymerization step is a polymer solution that is concentrated by heating to the boiling point of the good solvent or higher and adjusting the polymer concentration, as described later, as a pre-stage for carrying out the precipitation step described later. May be obtained (concentration step). The concentration step is optional.
Next, as described later, polyphenylene ether is precipitated by mixing with a poor solvent of polyphenylene ether to produce a slurry (precipitation step).
Solution polymerization is a polymerization method in which polymerization is carried out in a good solvent of polyphenylene ether and precipitation of polyphenylene ether does not occur during the polymerization. All polyphenylene ether molecules obtained by solution polymerization are in a dissolved state, and the molecular weight distribution tends to be wide. The polymer solution in which polyphenylene ether is dissolved is subjected to a concentration step as necessary, and then mixed with a poor solvent of polyphenylene ether such as methanol in the subsequent step to obtain powdery polyphenylene ether.

<Good PPE solvent used in polymerization process>
The good solvent for polyphenylene ether used in the polymerization step is not limited to the following, but at least one selected from the group consisting of benzene, toluene, and xylene is preferable from the viewpoint of the solubility of polyphenylene ether.

  The polymerization method of polyphenylene ether is not limited to the following. For example, 2,6-xylenol is oxidatively polymerized using a complex of cuprous salt and amine described in US Pat. No. 3,306,874 as a catalyst. The method of doing is mentioned. Further, the methods described in US Pat. Nos. 3,306,875, 3,257,357 and 3,257,358, JP-B-52-17880, JP-A-50-51197, and JP-A-63-152628, etc. Is also preferred as a method for producing polyphenylene ether.

From the viewpoint of efficiently producing polyphenylene ether and from the viewpoint of producing polyphenylene ether having a molecular weight distribution (dispersion degree) in the preferred range described above, the monomer concentration in the polymerization step is 10 to 30 masses based on the total amount of the polymerization solution. % Is preferable, and 13 to 27% by mass is more preferable. When the concentration is 10% by mass or more, the production efficiency of polyphenylene ether increases.
On the other hand, when the concentration exceeds 30% by mass, it tends to be difficult to adjust to the above-mentioned preferred number average molecular weight. The present inventors presume this cause as follows. That is, when the monomer concentration exceeds 30% by mass, the liquid viscosity at the end of polymerization becomes high, and uniform stirring becomes difficult. Therefore, a heterogeneous reaction occurs, and an unexpected molecular weight polyphenylene ether may be obtained. As a result, it may be difficult to efficiently produce polyphenylene ether having a suitable number average molecular weight.

  The polyphenylene ether polymerization step is preferably performed while supplying an oxygen-containing gas. As the oxygen-containing gas, pure oxygen, oxygen and an inert gas such as nitrogen mixed at an arbitrary ratio, air, air and an inert gas such as nitrogen or rare gas mixed at an arbitrary ratio Things can be used.

The pressure in the reaction system in the polymerization step may be normal pressure, or may be reduced or increased as necessary.
The supply rate of the oxygen-containing gas described above can be arbitrarily selected in consideration of heat removal, polymerization rate, etc., but is preferably 5 NmL / min or more as pure oxygen per mole of phenol compound used for polymerization, and is 10 NmL / min or more. More preferred.

In the polymerization process of polyphenylene ether, neutral salts such as alkali metal hydroxide, alkaline earth metal hydroxide, alkali metal alkoxide, magnesium sulfate, calcium chloride, etc. Zeolite or the like may be added.
Further, a surfactant that has been conventionally known to have an effect of improving the polymerization activity may be added to the polymerization solvent. As such a surfactant, for example, trioctylmethylammonium chloride known as Aliquat 336 and CapRiquat (trade name, manufactured by Dojindo Laboratories Co., Ltd.) can be mentioned. The amount of the surfactant used is preferably within a range not exceeding 0.1% by mass with respect to the total amount of the polymerization reaction raw material.

In the polymerization process of polyphenylene ether, a known catalyst generally used for producing polyphenylene ether may be added to the reaction system.
Examples of the catalyst include, but are not limited to, a catalyst composed of a transition metal ion having oxidation-reduction ability and an amine compound capable of complexing with the metal ion. Examples thereof include a catalyst system composed of a compound and an amine, a catalyst system composed of a manganese compound and an amine, and a catalyst system composed of a cobalt compound and an amine.

  In the polymerization process of polyphenylene ether, since the polymerization reaction proceeds efficiently under some alkaline conditions, it is preferable to add some alkali or amine. As a suitable catalyst in the polymerization process of polyphenylene ether, a catalyst containing a copper compound, a halogen compound and a diamine compound represented by the following formula (3) as constituent components can be mentioned.

... (3)

In said formula (3), R < ₉ >, R < ₁₀ >, R < ₁₁ > and R <_12> are each independently selected from the group which consists of a hydrogen atom and a C1-C6 linear or branched alkyl group. Indicates either.
Note that all of R ₉ , R ₁₀ , R ₁₁ and R ₁₂ are not hydrogen at the same time.
R ₁₃ represents a linear or branched alkylene group having 2 to 5 carbon atoms.

  Examples of the diamine compound represented by the above formula (3) include, but are not limited to, 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′-di- n-Propylethylenediamine, Ni-Propylethylene Diamine, N, N'-di-i-propylethylenediamine, Nn-butylethylenediamine, N, N'-di-n-butylethylenediamine, Ni-butylethylenediamine, N, N'-di-i-butyl Ethylenediamine, Nt-butylethylenediamine, N, N′-di-t-butylethylenediamine, N, N, N ′, N′-tetramethyl-1,3-diaminopropane, N, N, N′-trimethyl- 1,3-diaminopropane, N, N′-dimethyl-1,3-diaminopropane, N-methyl-1,3-diaminopropane, N, N, N ′, N′-tetramethyl-1,3-diamino -1-methylpropane, N, N, N ′, N′-tetramethyl-1,3-diamino-2-methylpropane, N, N, N ′, N′-tetramethyl-1,4-diamy Butane, N, N, N ', N'- tetramethyl-1,5-diaminopentane, and the like.

Preferred diamine compounds are those having 2 or 3 carbon atoms in the alkylene group (R ₁₃ ) connecting two nitrogen atoms in the formula (3) from the viewpoint of the ability to form a complex with a metal catalyst.
Although the usage-amount of these diamine compounds is not specifically limited, Usually, it is used in the range of 0.01 mol-10 mol with respect to 100 mol of phenolic compounds used at a superposition | polymerization process.

As said copper compound which comprises a catalyst, a cuprous compound, a cupric compound, or a mixture thereof can be used. Examples of the cuprous compound include, but are not limited to, cuprous chloride, cuprous bromide, cuprous sulfate, cuprous nitrate, and the like. Examples of the cupric compound include cupric chloride, cupric bromide, cupric sulfate, cupric nitrate, and the like. Among these, particularly preferred copper compounds are cuprous chloride, cupric chloride, cuprous bromide, and cupric bromide from the viewpoint of polymerization reaction activity.
Moreover, you may synthesize | combine these copper compounds from the halogen or acid corresponding to an oxide (for example, cuprous oxide), carbonate, a hydroxide, etc. For example, it can be synthesized by mixing cuprous oxide and a halogen compound (for example, a solution of hydrogen halide). These copper compounds may be used alone or in combination of two or more.

Examples of the halogen compound constituting the catalyst include, but are not limited to, hydrogen chloride, hydrogen bromide, hydrogen iodide, sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide. Potassium iodide, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide and the like. These may be used as an aqueous solution or a solution using an appropriate solvent.
These halogen compounds may be used alone or in combination of two or more. Preferred halogen compounds are an aqueous solution of hydrogen chloride and an aqueous solution of hydrogen bromide from the viewpoint of polymerization activity.

  The amount of copper compound and halogen compound used in the catalyst is not particularly limited, but when both the copper compound and the halogen compound are used, the halogen atom is preferably 2 to 20 times the number of moles of the copper atom, The preferred amount of copper atom used per 100 moles of the phenol compound used is in the range of 0.02 moles to 0.6 moles.

As a catalyst used in the polymerization step, for example, a tertiary monoamine compound or a secondary monoamine compound may be contained alone or in combination in addition to the above-described compounds.
The tertiary monoamine compound is an aliphatic tertiary amine including an alicyclic tertiary amine. Examples of the tertiary monoamine compound include, but are not limited to, trimethylamine, triethylamine, tripropylamine, tributylamine, triisobutylamine, dimethylethylamine, dimethylpropylamine, allyldiethylamine, dimethyl-n-butylamine. , Diethylisopropylamine, N-methylcyclohexylamine and the like.
These tertiary monoamine compounds may be used alone or in combination of two or more. Although the usage-amount is not specifically limited, 15 mol or less is preferable with respect to 100 mol of phenolic compounds used in a superposition | polymerization process.
The tertiary monoamine compound does not have to be added from the beginning to the reaction system in the polymerization step in the whole amount normally used. That is, some of them may be added in the middle, or some of them may be added sequentially from the start of polymerization. Moreover, you may add to the solution of a phenolic compound or a phenolic compound simultaneously with the start of superposition | polymerization, and may add with this.

Examples of the secondary monoamine compound include secondary aliphatic amines.
Examples of secondary aliphatic amines include, but are not limited to, dimethylamine, diethylamine, di-n-propylamine, di-i-propylamine, di-n-butylamine, di-i- Examples include butylamine, di-t-butylamine, dipentylamines, dihexylamines, dioctylamines, didecylamines, dibenzylamines, methylethylamine, methylpropylamine, methylbutylamine, and cyclohexylamine.
Further, as the secondary monoamine compound, a secondary monoamine compound containing an aromatic can also be applied. Examples of secondary monoamine compounds containing aromatics are not limited to the following, but include, for example, N-phenylmethanolamine, N-phenylethanolamine, N-phenylpropanolamine, N- (m-methylphenyl) ethanol. Amine, N- (p-methylphenyl) ethanolamine, N- (2 ′, 6′-dimethylphenyl) ethanolamine, N- (p-chlorophenyl) ethanolamine, N-ethylaniline, N-butylaniline, N— Examples thereof include methyl-2-methylaniline, N-methyl-2,6-dimethylaniline, diphenylamine and the like. The above-mentioned secondary monoamine compounds may be used alone or in combination of two or more. Although the usage-amount of a secondary monoamine compound is not specifically limited, 15 mol or less is suitable with respect to 100 mol of phenol compounds used in a superposition | polymerization process.

(Post-treatment after polymerization reaction of polyphenylene ether)
A predetermined post-treatment step may be performed after the polymerization step described above.
The specific method of the post-treatment step is not particularly limited, but usually an acid such as hydrochloric acid or acetic acid, ethylenediaminetetraacetic acid (EDTA) and its salt, nitrilotriacetic acid and its salt, etc. are used as a reaction solution. In addition, there is a method of deactivating the catalyst.
Since the polymerization solution at the end of the polymerization is in a state where polyphenylene ether is dissolved in a good solvent, for the purpose of washing and removing the catalyst, the solubility of polyphenylene ether is low, and phase separation from the good solvent of polyphenylene ether, such as water, etc. It is preferable to repeatedly perform the washing treatment using a solution containing the above solvent as a main component.

(Concentration of a good solvent solution of polyphenylene ether)
In the method for producing polyphenylene ether of this embodiment, a good solvent solution of polyphenylene ether obtained by the polymerization process of polyphenylene ether, that is, a polymer solution, if necessary, is heated to a temperature equal to or higher than the boiling point of the good solvent, It is preferable to perform a step of concentrating the good solvent solution of polyphenylene ether so that the concentration of the polyphenylene ether falls within the range of the formula (I) by extracting the generated good solvent vapor out of the system.
30 <X ≦ 48 (I)
That is, the polyphenylene ether concentration (X [mass%]) in the good solvent solution of polyphenylene ether is adjusted to a range of more than 30 mass% and 48 mass% or less.
X is preferably more than 30% by mass and 44% by mass or less, and more preferably more than 30% by mass and 40% by mass or less.

(Polyphenylene ether precipitation process)
In the polyphenylene ether precipitation step, first, as the initial charge liquid of the precipitation tank, from the viewpoint of stable operation, the mass ratio of the poor solvent and the good solvent (initial charge poor solvent / initial charge good solvent), It is preferable to charge so that it may become the range of 0.4-1.2. If the mass ratio of the poor solvent and the good solvent is outside the above range, the polymer may be fixed in the precipitation tank or the polymer may not be precipitated.
The polymer solution obtained through the polymerization step described above or the concentration step described above and a poor solvent are added to the precipitation tank and stirred. Thereby, the solvent ratio in the precipitation tank is adjusted to a range satisfying the following formula (II), polyphenylene ether is precipitated, and a slurry is generated.
In the present embodiment, in the precipitation step, the polyphenylene ether-containing polymer solution concentration (X) charged into the precipitation tank is more than 30% by mass and 48% by mass or less, and the poor solvent added to the precipitation tank The mass ratio with respect to the good solvent (poor solvent / good solvent) = Y shall satisfy the condition shown in the following formula (II).
Y ≦ min {0.45, 13.252 · (X / 100) ² −0.8725 · X / 100−0.5196} (II)
Here, Y ≦ min {a, b} means that Y is equal to or smaller than the smaller one of a and b.

The “polyphenylene ether-containing polymer solution concentration (X) to be introduced into the precipitation tank in the precipitation step” means the concentration of the polymer in the good solvent in the polymer solution obtained in the polymerization step or the concentration step described above. It means that the good solvent of the initial charge liquid is not included.
The “poor solvent to be added to the precipitation tank” means a poor solvent to be added in order to deposit the polymer solution after the initial charge of the precipitation tank is completed, and then to deposit polyphenylene ether. The poor solvent of the initial charge liquid is not included.
That is, in this specification, Y = (poor solvent added in the precipitation step / good solvent contained in the polymer solution).

When the mass ratio of the poor solvent added to the precipitation tank to the good solvent in the polymer solution (poor solvent / good solvent) = Y satisfies the above formula (II), the slurry containing the precipitated polyphenylene ether is solid-liquid separated. After the post-treatment process such as drying, the resulting polyphenylene ether powder contains an appropriate fine powder and contains an appropriate good solvent, so that a polyphenylene ether powder suitable for compression granulation is obtained. Can be generated.
By setting the mass ratio of the poor solvent to the good solvent (poor solvent / good solvent) within the range of the formula (II), the composition becomes relatively good solvent-rich and the adhesion of the polymer is increased. Therefore, it is presumed that the pulverization in the post-processing step is easy to proceed, and the fine powder is appropriately contained as described above. Moreover, since the good solvent which remains in polyphenylene ether powder increases after drying, it is estimated that granulation property (adhesiveness in compression granulation) improves. That is, it is easy to pack closely, and also has a binder effect of the remaining good solvent, making it possible to form a high-strength compressed granulated product. The occurrence of is reduced.

  In this embodiment, in the precipitation step, a polymer solution having a polyphenylene ether concentration in the good solvent of more than 30% by mass and 48% by mass or less is used (formula (I)), but the polyphenylene ether in the good solvent solution of polyphenylene ether is used. When the ether concentration is 30% by mass or less, the amount of the poor solvent for precipitating polyphenylene ether becomes large, which is not preferable in terms of production efficiency. Moreover, when recovering and using a poor solvent, there also exists a disadvantage that recovery cost becomes large. On the other hand, when the polyphenylene ether concentration in the good solvent of polyphenylene ether exceeds 48% by mass, the liquid viscosity becomes high and the equipment cost of peripheral equipment such as a pump becomes large, which is not preferable. Furthermore, if the polymer solution is not kept at a high temperature, there is a disadvantage that the polymer is solidified and operation becomes difficult.

<Poor solvent>
As the poor solvent used in the precipitation step in the method for producing the polyphenylene ether powder of the present embodiment, the following solvents can be used.
The poor solvent is a solvent that does not dissolve polyphenylene ether at all or slightly dissolves it.
Examples of the poor solvent include, but are not limited to, ketones and alcohols. Preferably, it is a C1-C10 alcohol. For example, methanol, ethanol, propanol, isopropanol, n-butanol, pentanol, hexanol, ethylene glycol, acetone, methyl ethyl ketone, water and the like can be mentioned.
These poor solvents may be used alone or in combination of two or more.
As the poor solvent, methanol, ethanol, isopropanol, n-butanol, 2-butanol, acetone, methyl ethyl ketone, and water are preferable from the viewpoint of particle strength. Among the poor solvents, a combination of water and another poor solvent is preferable from the viewpoint of particle uniformity, and the water content at this time is 0.05 to 30 from the viewpoint of uniform precipitation particle size and scale prevention. % By mass is preferable, and more preferably 0.5 to 20% by mass.

As described above, in the present embodiment, in the polyphenylene ether precipitation step, when the mass ratio of the poor solvent to be added and the good solvent in the polymer solution (poor solvent / good solvent) is Y, Y is The concentration of polyphenylene ether added to the precipitation tank in the good solvent solution is within the range represented by the following formula (II) using X (mass%).
30 <X ≦ 48 (I)
Y ≦ min {0.45, 13.252 · (X / 100) ² −0.8725 · X / 100−0.5196} (II)
Here, Y ≦ min {a, b} means that Y is equal to or smaller than the smaller one of a and b.
By adjusting the ratio of the good solvent solution and the poor solvent of polyphenylene ether added to the precipitation tank, the Y can be controlled so as to satisfy the range of the formula (II).
The ratio (Y) of the poor solvent to the good solvent has an azeotropic composition in the vicinity of 0.45, and if it exceeds this, the good solvent tends to evaporate together with the poor solvent having a higher ratio than the good solvent during drying. Therefore, it is not preferable.

  Further, when Y is in the range of the formula (II), the polymer concentration in the precipitation tank (slurry), ie, [(polymer mass present in the precipitation tank) / (good solvent existing in the precipitation tank after addition) And the total mass of the poor solvent)] × 100 (% by mass) is 23% by mass or more, so the concentration becomes relatively high, the movement of the particles is limited, pulverization occurs due to wear and stirring, and the particle size is moderate. Fluctuates. Moreover, since it becomes a wet cake with a high ratio of a good solvent, the residual amount of the good solvent in polyphenylene ether powder also increases, and it is excellent in compression granulation property.

  The temperature of the mixed solution in the precipitation step is preferably 30 to 63 ° C., more preferably 40 to 60 ° C. from the viewpoint of particle size control.

  The residence time of the polyphenylene ether in the precipitation tank is preferably 0.25 to 5 minutes, more preferably 0.5 to 3.0 minutes from the viewpoint of particle size control.

The shape of the precipitation tank is preferably provided with at least one stirrer blade selected from the group consisting of an inclined paddle blade, a screw blade, and a ribbon blade. In the precipitation step described above, it is preferable to perform stirring with these stirring blades.
Further, from the viewpoint of stabilizing the fluidity, it is preferable to use one provided with at least one baffle. The stirring blade is preferably a lower discharge blade.

  The precipitation tank is preferably provided with a draft tube from the viewpoint of particle size control. In this case, the draft tube is provided with at least one stirrer blade selected from the group consisting of inclined paddle blades, screw blades, and ribbon blades from the viewpoint of creating a strong circulation flow inside and outside the draft tube and preventing sticking during operation. The stirring blade inside the draft tube is preferably a lower discharge blade. In the precipitation step described above, it is preferable to perform stirring using the stirring tank which is the lower discharge blade. Thereby, the inside of a draft tube can be circulated as a downward flow, and the outside of a draft tube can be circulated as an upward flow, and the effect that the stirring operation state is stabilized is acquired.

  Moreover, as a precipitation tank used in the precipitation step, one having a stirring blade that is a ribbon blade is preferably used on the outside of the draft tube from the viewpoint of strengthening the circulation flow inside and outside the draft tube. The stirring blade, which is the ribbon blade on the outside of the draft tube, is preferably an upper discharge blade from the viewpoint of creating a flow in the same direction as the lower discharge blade provided in the draft tube. Stirring is preferably performed with a stirring blade that is an upper discharge blade.

(Washing process)
In the method for producing the polyphenylene ether powder of the present embodiment, a poor solvent may be added to the polyphenylene ether slurry obtained by the above-described precipitation step and stirred as necessary to wash the good solvent. Good.
Then, it isolate | separates into a solvent and wet polyphenylene ether by a solid-liquid separation process.
The apparatus for performing solid-liquid separation is not particularly limited, but is a centrifuge (vibration type, screw type, decanter type, basket type, etc.), vacuum filter (drum type filter, belt filter, rotary vacuum filter). , Young filter, Nutsche, etc.), filter press, and roll press can be used.

  In the manufacturing method of the polyphenylene ether powder of this embodiment, you may further have the process of crushing the said wet polyphenylene ether mechanically. Thereby, the fine powder rate can be adjusted. The crushing apparatus is not particularly limited, and a jaw crusher, a cone crusher, a hammer mill, a feather mill, a ball mill, a high-speed rotating mill, a jet mill, and the like can be used.

(Drying process)
In the method for producing polyphenylene ether of the present embodiment, it is preferable to perform a drying process after performing a precipitation process as described above, and further performing a washing process, a solid-liquid separation process, and a crushing process as necessary. .
The drying treatment is preferably performed at a drying temperature of at least 60 ° C. The drying temperature is more preferably 80 ° C. or higher, further preferably 120 ° C. or higher, still more preferably 140 ° C. or higher, and particularly preferably 150 ° C. or higher.
The amount of the good solvent remaining in the polyphenylene ether powder after the drying treatment is preferably more than 0.3% by mass from the viewpoint of improving the granulation property, and the working environment during the granulation step From the viewpoint, it is preferably less than 1.5% by mass.
If the polyphenylene ether powder is dried at a temperature of less than 60 ° C., the amount of good solvent remaining in the polyphenylene ether powder may not be controlled in the range of more than 0.3% by mass and less than 1.5% by mass. is there.
The amount of good solvent remaining in the polyphenylene ether powder is more preferably 0.5% by mass or more, and further preferably 0.7% by mass or more.
In order to obtain dry polyphenylene ether powder with high efficiency, a method of increasing the drying temperature, a method of increasing the degree of vacuum in the drying atmosphere, a method of stirring during drying, etc. are effective. Is preferable from the viewpoint of production efficiency.
In the drying step, it is preferable to use a dryer having a mixing function. Examples of the mixing function include a stirring type and a rolling type dryer. As a result, the processing amount can be increased and the productivity can be maintained high.

(Characteristics of polyphenylene ether powder)
In the method for producing the polyphenylene ether powder of the present embodiment, the fine powder ratio (content ratio of particles of 105 μm or less) in the polyphenylene ether powder after the drying step is preferably 20% by mass or more, and more preferably. Is 25% by mass or more, more preferably 30% by mass or more.
When the fine powder ratio is 20% by mass or more, when the polyphenylene ether powder is compression-molded, it is easy to densely fill, and a high strength molded product tends to be obtained. In addition, the fine powder rate can be suppressed during re-pulverization, high strength can be obtained even in the granulated polyphenylene ether powder, and there is a tendency that fine powder can be suppressed even in the air transportation.
In addition, a fine powder rate can be measured by the method as described in the Example mentioned later.

The amount of residual good solvent in the polyphenylene ether powder obtained by the production method of the present embodiment is preferably more than 0.3% by mass, more preferably 0.5% by mass or more, and further preferably 0.7%. It is at least mass%, more preferably at least 1.0 mass%.
When the content of the good solvent exceeds 0.3% by mass, when the polyphenylene ether powder is compression-molded, sufficient adhesion is obtained and a high-strength molded product tends to be obtained. In addition, the fine powder rate can be suppressed during re-pulverization, high strength can be obtained even in the granulated polyphenylene ether powder, and there is a tendency that fine powder can be suppressed even in the air transportation.

The polyphenylene ether powder obtained by the production method of the present embodiment can be processed into a polyphenylene ether powder having further excellent handleability by compression molding.
Although it does not specifically limit as an apparatus to compress, For example, compression molding machines, such as a compression roll type, a briquetting roll type, and a tableting type, are mentioned. Specifically, it is preferable to perform compression in a temperature range of 5 to 200 ° C. using polyphenylene ether powder to obtain a molded body having a density of 0.70 to 1.06 g / cm ³ .

Furthermore, a desired polyphenylene ether powder can be obtained by pulverizing the molded body obtained by the compression molding.
The pulverizer is not particularly limited, and examples thereof include a coarse pulverizer, an intermediate pulverizer, and a fine pulverizer. Examples of the coarse pulverizer include a jaw crusher, a gyratory crusher, and a Schletter. Examples of the intermediate pulverizer include an impact pulverizer such as a hammer mill and a disintegrator, a roll pulverizer, and an edge runner. Examples of the fine pulverizer include a centrifugal pulverizer, a ball mill, a vibration mill, a colloid mill, a mortar, and a mill.

As described above, the temperature range of the powder during compression molding is preferably 5 to 200 ° C.
There is a tendency to obtain a molded product having sufficient strength by compression molding at 5 ° C. or higher, and an amine added at the time of polymerization of polyphenylene ether by compression molding at 200 ° C. or lower and bonded to the polymer terminal. It tends to be possible to suppress the detachment of the amine, and to prevent deterioration of quality during processing.
The temperature at the time of compression molding is more preferably 80 ° C. or higher and 165 ° C. or lower from the viewpoint of obtaining a molded body that is stronger and superior in quality.

Moreover, as above-mentioned, it is preferable to make the density of a molded object into the range of 0.70-1.06g / cm < ³ >.
By setting the density of the molded body to 0.70 g / cm ³ or more, a molded body having sufficient strength can be obtained, and when re-pulverization is performed, generation of fine powder tends to be suppressed. Further, by setting the density of the molded body to 1.06 g / cm ³ or less, melting due to generation of local heat due to shear during molding can be prevented, and generation of fine powder can be suppressed. It is in. In addition, the release of amine bonded to the polymer end due to shear heat generation tends to be suppressed, and quality deterioration during processing tends to be prevented.
The density of the molded body is more preferably 0.75 to 1.04 g / cm ³ , whereby the molded body is not subjected to local shearing heat and is taken out as an aggregate of strong powder with few melting parts. Tend to be able to. Furthermore, it tends to be able to obtain a polyphenylene ether powder having good powder characteristics by re-pulverizing it.

  The content of fine particles having a particle size of 105 μm or less in the polyphenylene ether powder after re-grinding the molded body is preferably 0.5% by mass or less, more preferably 0.4% by mass or less, Preferably it is 0.3 mass% or less.

  In addition, the polyphenylene ether powder after re-pulverizing the molded body preferably has a ratio of particles having a particle size of 105 μm to 5 mm of 90% by mass or more, more preferably, from the viewpoint of powder handling. It is 93 mass% or more, More preferably, it is 95 mass% or more. If the ratio of particles having a particle size of 105 μm to 5 mm is 95% by mass or more, the handling properties such as fine powder scattering and poor bite of the extruder tend to be kept good.

  The content ratio of fine particles having a particle size of 105 μm or less after re-grinding the molded product and the ratio of particles having a particle size of 105 μm to 5 mm are obtained by sieving the polyphenylene ether particles, measuring the mass of each fraction, It can be calculated by reading the content (mass%) of particles of 105 μm or less obtained from the cumulative curve of the distribution and the content of particles of 5 mm or more and subtracting them from 100 mass%.

Hereinafter, the present invention will be specifically described with reference to specific examples and comparative examples. However, the present invention is not limited to the following examples.
First, measurement methods such as physical properties and characteristics applied to Examples and Comparative Examples are shown below.

((1) Measurement of average particle size, calculation of fine powder ratio)
The polyphenylene ether granules obtained in Examples and Comparative Examples described later are sieved using a micro electromagnetic vibration sieve (M-2 type manufactured by Tsutsui Riken Kikai Co., Ltd.), and the mass of each fractionation part is measured. did. From the cumulative curve of the particle size distribution, the particle size (median diameter) corresponding to the median cumulative value was defined as the average particle size.
Similarly, the content rate (mass%) of particles of 105 μm or less obtained from the cumulative curve of particle size distribution, that is, the fine powder rate was calculated.

((2) Measurement of reduced viscosity)
A 0.5 g / dL chloroform solution of the polyphenylene ether powder obtained in Examples and Comparative Examples described later is prepared, and the reduced viscosity (ηsp / c) [dL / g] at 30 ° C. is measured using an Ubbelohde viscosity tube. Asked.

((3) Measurement of molecular weight, calculation of molecular weight distribution (dispersion degree))
Using a gel permeation chromatography system 21 manufactured by Showa Denko Co., Ltd. as a measuring device, a calibration curve is prepared with standard polystyrene, and using this calibration curve, polyphenylene ether powders obtained in Examples and Comparative Examples described later The weight average molecular weight (Mw) and number average molecular weight (Mn) of the body were measured. Moreover, molecular weight distribution Mw / Mn (dispersion degree) was computed from these.
As the standard polystyrene, those having a molecular weight of 3650000, 217000, 1090000, 681000, 204000, 52000, 30200, 13800, 3360, 1300, and 550 were used.
As the column, a column in which two K-805L manufactured by Showa Denko KK were connected in series was used.
As the solvent, chloroform was used, the solvent flow rate was 1.0 mL / min, and the column temperature was 40 ° C.
As a measurement sample, a 1 g / L chloroform solution of polyphenylene ether was prepared and used.
The UV wavelength of the detector was 254 nm for standard polystyrene and 283 nm for polyphenylene ether.

((4) Residual toluene concentration)
The toluene concentration in the dried polyphenylene ether powder was measured by gas chromatography.
As a pretreatment, a predetermined amount of polyphenylene ether powder was dissolved in 10 times the amount of chloroform, the solution was directly injected into gas chromatography, and the toluene concentration (mass%) in the polyphenylene ether was calculated from the peak area value.

((5) Evaluation of granulation after compression molding and re-grinding)
A briquette roll compactor (diameter: 258 mm × width: 38 mm roll) having a recess having a diameter of about 5 mm was used as a compression molding machine.
The plate-like molded body obtained by compression in the roll part was pulverized by a hammer mill type pulverizer.
The particle size adjustment in the pulverizer was performed by discharging polyphenylene ether powder having a diameter of 5 mm or less using a screen attached to a hammer mill.
The average particle diameter and fine powder ratio of the obtained polyphenylene ether were measured by the method (1).

[Production of polyphenylene ether solution]
<Production Example 1>
A 40 liter jacketed polymerization tank equipped with a sparger for introducing an oxygen-containing gas, a stirring turbine blade and a baffle at the bottom of the polymerization tank, and equipped with a reflux condenser in the vent gas line at the top of the polymerization tank was added to a 0.5 L / min. While blowing nitrogen gas at a flow rate, 4.02 g of cupric oxide, 29.876 g of 47 mass% hydrogen bromide aqueous solution, 9.684 g of di-t-butylethylenediamine, 46.88 g of di-nbutylamine, 122 .28 g of butyldimethylamine, 17.53 kg of toluene, and 1.5 kg of 2,6-dimethylphenol were added, and the mixture was stirred until it became a homogeneous solution and the internal temperature of the polymerization tank reached 25 ° C.
Next, while introducing dry air from the sparger at a rate of 32.8 NL / min into the polymerization tank, 1.62 kg of 2,6-dimethylphenol and 3.12 kg of toluene were added from the plunger pump. Added to the polymerization tank over 30 minutes.
The polymerization solution at the end of the polymerization was in the form of a solution. Dry air was passed through for 86 minutes to obtain a polymerization mixture. During the polymerization, the internal temperature was controlled to 40 ° C.
Aeration of dry air was stopped, and 2.38 kg of a 1.85% by mass aqueous solution of ethylenediaminetetraacetic acid tetrasodium salt (a reagent manufactured by Dojindo Laboratories) was added to the polymerization mixture. The polymerization mixture was stirred at 70 ° C. for 120 minutes, and then allowed to stand for 90 minutes, and the organic phase and the aqueous phase were separated by liquid-liquid separation. The separated organic phase was a toluene solution containing 13.1% by mass of polyphenylene ether, and this was used as a polymer solution (1).

[Precipitation of polyphenylene ether]
<Example 1>
The polymer solution (1) obtained in Production Example 1 was placed in a jacketed stirring tank, and heated by flowing a 120 ° C. heating medium through the jacket.
Steam generated from toluene as a main component was cooled by a condenser, and toluene was extracted out of the system, and concentrated until the polymer concentration in the stirring tank reached 30.5% by mass. This operation was repeated to produce 90 kg of a polymer solution having a polymer concentration of 30.5% by mass.
Next, the polymer was deposited using a precipitation tank with a jacket provided with a draft tube described in Example 1 of International Publication No. 2003/064499 and four inclined paddle blades. In addition, it was set as the precipitation tank which added and provided four baffles outside the draft tube.
The volume of the liquid staying in this precipitation tank was 1100 mL.
The precipitation tank was charged with 500 g of toluene and 500 g of methanol, and stirred at 1500 rpm.
The precipitation tank was provided with an overflow line, and when the amount of the internal liquid exceeded 1100 mL, the internal liquid overflowed and was discharged outside the tank.
The position of the feed line was the same as the position described in Example 1 of International Publication No. 2003/064499.
175 g / min of methanol containing 3.0% by mass of water and 597 g / min of the above 30.5% by mass polymer solution were fed into the precipitation tank.
The paddle blade continued to rotate at 1500 rpm.
The operation was continued for about 160 minutes. The slurry liquid was discharged at 772 g / min, and this was fed to the washing tank by a slurry pump.
To the washing tank, methanol was fed from a separate line at 175 g / min, and the slurry in the slurry was stirred to replace and wash the toluene in the polyphenylene ether particles.
About 150 kg of washing slurry liquid having a slurry concentration of about 19% by mass was produced.
The slurry was divided every 10 kg and filtered through a basket centle (Tanabe Wiltech model 0-15).
After each filtration, 1.5 kg of methanol was sprayed onto the wet polyphenylene ether in the basket centre and filtered again to obtain wet polyphenylene ether.
Next, the wet polyphenylene ether was put into a feather mill (FM-1S manufactured by Hosokawa Micron Co., Ltd.) on which a 10 mm round hole mesh was set. A powder was obtained.
Each measurement was performed by the method mentioned above about the obtained polyphenylene ether powder.
The measurement results are shown in Table 1.

<Example 2>
The polymer solution (1) obtained in Production Example 1 was concentrated to 38.0% by mass in the same manner as described in Example 1. This operation was repeated to produce 70 kg of a polymer solution having a polymer concentration of 38.0% by mass.
Except that methanol containing 3.0% by mass of water was fed at 165 g / min, 38.0% by mass polymer solution was fed at 607 g / min, and methanol was fed to the washing tank at 170 g / min. Was carried out in the same manner as in Example 1 to obtain a polyphenylene ether powder.
Each measurement was performed by the method mentioned above about the obtained polyphenylene ether powder.
The measurement results are shown in Table 1.

<Comparative Example 1>
The polymer solution (1) obtained in Production Example 1 was concentrated to 30.5% by mass in the same manner as described in Example 1. This operation was repeated to produce 90 kg of a polymer solution having a polymer concentration of 30.5% by mass.
The same procedure as in Example 1 was conducted except that 255 g / min of methanol containing 3.0% by mass of water and 517 g / min of 30.5% by mass of polymer solution were fed into the precipitation tank to obtain a polyphenylene ether powder. It was.
Each measurement was performed by the method mentioned above about the obtained polyphenylene ether powder.
The measurement results are shown in Table 1.

<Comparative example 2>
The polymer solution (1) obtained in Production Example 1 was concentrated to 30.5% by mass in the same manner as described in Example 1. This operation was repeated to produce 90 kg of a polymer solution having a polymer concentration of 30.5% by mass.
The same procedure as in Example 1 was conducted except that 260 g / min of methanol containing 3.0% by mass of water and 512 g / min of 30.5% by mass of polymer solution were fed into the precipitation tank, to obtain a polyphenylene ether powder. It was.
Each measurement was performed by the method mentioned above about the obtained polyphenylene ether powder.
The measurement results are shown in Table 1.

<Comparative Example 3>
The polymer solution (1) obtained in Production Example 1 was concentrated to 38.0% by mass in the same manner as described in Example 1. This operation was repeated to produce 70 kg of a polymer solution having a polymer concentration of 38.0% by mass.
The same procedure as in Example 1 was conducted except that 240 g / min of methanol containing 3.0% by mass of water and 532 g / min of a 30.5% by mass polymer solution were fed into the precipitation tank to obtain a polyphenylene ether powder. It was.
Each measurement was performed by the method mentioned above about the obtained polyphenylene ether powder.
The measurement results are shown in Table 1.

Yupper in Table 1 is as follows.
When the mass ratio of poor solvent to good solvent (poor solvent / good solvent) when precipitating polyphenylene ether is Y, Y is the polyphenylene ether concentration in the good solvent solution of polyphenylene ether: X (mass%). The relational expression represented by the following expression is satisfied.
Y ≦ min {0.45, 13.252 · (X / 100) ² −0.8725 · (X / 100) −0.5196}
Here, Y ≦ min {a, b} means that Y is equal to or smaller than the smaller one of a and b.
In Table 1: Yupper = min {0.45, 13.252 · (X / 100) ² −0.8725 · (X / 100) −0.5196}, and “Yupper” in the present invention means that the value of Y is It means that it is a requirement that it is not more than the value of Yupper.

The polyphenylene ether powders produced in Examples 1 and 2 and Comparative Examples 1 to 3 were evaluated for granulation according to the above.
Compared with Comparative Examples 1, 2, and 3, Examples 1 and 2 showed that the fine powder rate was high and the amount of residual toluene was large. The reason why the fine powder rate is high is that the fine particles are precipitated in a good solvent-rich composition and after the subsequent steps, the particles are easily pulverized in the steps after the precipitation.
In addition, the reason for the large amount of residual toluene is that the mixed solvent of the azeotropic composition is preferentially volatilized because it is dried with a composition having less poor solvent than the azeotropic composition of toluene, which is a good solvent, and methanol, which is a poor solvent. This is because the solvent tends to remain in the polyphenylene ether.

[Compression molding of polyphenylene ether powder]
<Example 3>
The raw material used was the polyphenylene ether powder produced in Example 1.
The compression molding conditions were as follows: temperature: 120 ° C., compact density [specific gravity]: 1.003 g / cm ³ , molding pressure: 70 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 2.

<Example 4>
The raw material used was the polyphenylene ether powder produced in Example 1.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.908 g / cm ³ , molding pressure: 30 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 2.

<Example 5>
The raw material used was the polyphenylene ether powder produced in Example 2.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.823 g / cm ³ , molding pressure: 70 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 2.

<Example 6>
The raw material used was the polyphenylene ether powder produced in Example 2.
The compression molding conditions were temperature: 120 ° C., compact density: 0.799 g / cm ³ , molding pressure: 30 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 2.

<Comparative example 4>
The raw material used was the polyphenylene ether powder produced in Comparative Example 1.
The compression molding conditions were temperature: 120 ° C., compact density: 0.885 g / cm ³ , molding pressure: 70 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 3.

<Comparative Example 5>
The raw material used was the polyphenylene ether powder produced in Comparative Example 1.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.856 g / cm ³ , molding pressure: 30 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 3.

<Comparative Example 6>
The raw material used was the polyphenylene ether powder produced in Comparative Example 2.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.783 g / cm ³ , molding pressure: 70 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 3.

<Comparative Example 7>
The raw material used was the polyphenylene ether powder produced in Comparative Example 2.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.703 g / cm ³ , molding pressure: 30 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 3.

<Comparative Example 8>
The raw material used was the polyphenylene ether powder produced in Comparative Example 3.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.883 g / cm ³ , molding pressure: 70 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 3.

<Comparative Example 9>
The raw material used was the polyphenylene ether powder produced in Comparative Example 3.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.834 g / cm ³ , molding pressure: 30 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 3.

  In Examples 3 to 6, since the polyphenylene ether powders of Examples 1 and 2 were used, molding with sufficient strength due to both the fine packing with fine powder and the binder effect of residual good solvent (toluene). A body was obtained, and after re-grinding, the fine powder rate was significantly reduced.

<Example 7>
The polymer solution (1) obtained in Production Example 1 was concentrated to 40.0% by mass in the same manner as described in Example 1. This operation was repeated to produce 70 kg of a polymer solution having a polymer concentration of 40.0% by mass.
Except that methanol containing 3.0% by mass of water was fed at 165 g / min, 40.0% by mass polymer solution was fed at 607 g / min, and methanol was fed to the washing tank at 170 g / min. In the same manner as in Example 1, polyphenylene ether powder was obtained.
Each measurement was performed by the method mentioned above about the obtained polyphenylene ether powder.
Table 4 shows the measurement results.

<Comparative Example 10>
The polymer solution (1) obtained in Production Example 1 was concentrated to 40.0% by mass in the same manner as described in Example 1. This operation was repeated to produce 90 kg of a polymer solution having a polymer concentration of 40.0% by mass.
The same procedure as in Example 1 was carried out except that 310 g / min of methanol containing 3.0% by mass of water and 462 g / min of 40.0% by mass polymer solution were fed into the precipitation tank to obtain a polyphenylene ether powder. It was.
Each measurement was performed by the method mentioned above about the obtained polyphenylene ether powder.
Table 4 shows the measurement results.

<Comparative Example 11>
The polymer solution (1) obtained in Production Example 1 was concentrated to 22.0% by mass in the same manner as described in Example 1. This operation was repeated to produce 90 kg of a polymer solution having a polymer concentration of 22.0% by mass.
The same procedure as in Example 1 was carried out except that 245 g / min of methanol containing 3.0% by mass of water and 527 g / min of 22.0% by mass of polymer solution were fed into the precipitation tank to obtain a polyphenylene ether powder. It was.
Each measurement was performed by the method mentioned above about the obtained polyphenylene ether powder.
Table 4 shows the measurement results.

<Comparative Example 12>
The polymer solution (1) obtained in Production Example 1 was concentrated to 20.0% by mass in the same manner as described in Example 1. This operation was repeated to produce 90 kg of a polymer solution having a polymer concentration of 20.0% by mass.
The same procedure as in Example 1 was conducted except that 570 g / min of methanol containing 3.0% by mass of water and 202 g / min of 20.0% by mass of the polymer solution were fed into the precipitation tank to obtain a polyphenylene ether powder. It was.
Each measurement was performed by the method mentioned above about the obtained polyphenylene ether powder.
Table 4 shows the measurement results.

<Comparative Example 13>
The polymer solution (1) obtained in Production Example 1 was concentrated to 40.0% by mass in the same manner as described in Example 1. This operation was repeated to produce 90 kg of a polymer solution having a polymer concentration of 40.0% by mass.
The same procedure as in Example 1 was carried out except that 520 g / min of methanol containing 3.0% by mass of water and 252 g / min of 40.0% by mass polymer solution were fed into the precipitation tank to obtain a polyphenylene ether powder. It was.
Each measurement was performed by the method mentioned above about the obtained polyphenylene ether powder.
Table 4 shows the measurement results.

<Example 8>
The raw material used was the polyphenylene ether powder produced in Example 7.
The compression molding conditions were temperature: 120 ° C., compact density [specific gravity]: 1.001 g / cm ³ , molding pressure: 70 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 5.

<Example 9>
The raw material used was the polyphenylene ether powder produced in Example 7.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.928 g / cm ³ , molding pressure: 30 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 5.

<Comparative example 14>
The raw material used was the polyphenylene ether powder produced in Comparative Example 10.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.815 g / cm ³ , molding pressure: 70 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 5.

<Comparative Example 15>
The raw material used was the polyphenylene ether powder produced in Comparative Example 10.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.699 g / cm ³ , molding pressure: 30 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 5.

<Comparative Example 16>
The raw material used was the polyphenylene ether powder produced in Comparative Example 11.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.899 g / cm ³ , molding pressure: 70 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 5.

<Comparative Example 17>
The raw material used was the polyphenylene ether powder produced in Comparative Example 11.
The compression molding conditions were temperature: 120 ° C., compact density: 0.725 g / cm ³ , molding pressure: 30 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 5.

<Comparative Example 18>
The raw material used was the polyphenylene ether powder produced in Comparative Example 12.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.789 g / cm ³ , molding pressure: 70 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 5.

<Comparative Example 19>
The raw material used was the polyphenylene ether powder produced in Comparative Example 12.
The compression molding conditions were temperature: 120 ° C., compact density: 0.679 g / cm ³ , molding pressure: 30 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 5.

<Comparative Example 20>
The raw material used was the polyphenylene ether powder produced in Comparative Example 13.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.781 g / cm ³ , molding pressure: 70 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 5.

<Comparative Example 21>
The raw material used was the polyphenylene ether powder produced in Comparative Example 13.
The compression molding conditions were as follows: temperature: 120 ° C., compact density: 0.673 g / cm ³ , molding pressure: 30 kg / cm ² . Evaluation was performed according to (5) above. The evaluation results are shown in Table 5.

  The method for producing the polyphenylene ether powder of the present invention has industrial applicability as a production technology for materials such as automobile parts, heat-resistant parts, electronic equipment parts, industrial parts, coating agents, and insulating coatings. doing.

Claims (16)

A polymerization step of polymerizing a phenol compound in a good solvent of polyphenylene ether to obtain a polymer solution;
Adding a polymer solvent and a poor solvent for polyphenylene ether to a precipitation tank, and depositing polyphenylene ether to form a slurry; and
Have
In the polymer solution added to the precipitation tank, the concentration of polyphenylene ether in a good solvent solution is X (mass%),
When the mass ratio (poor solvent / good solvent) of the poor solvent added to the precipitation tank and the good solvent in the polymer solution in the precipitation step is Y, the X and Y are represented by the following formula (I), A method for producing a polyphenylene ether powder that satisfies (II).
30 <X ≦ 48 (I)
Y ≦ min {0.45, 13.252 · (X / 100) ² −0.8725 · (X / 100) −0.5196} (II)
(In formula (II), Y ≦ min {a, b} means that Y is equal to or smaller than the smaller value of either a or b.)   The polymer solution obtained by the said polymerization process after the said polymerization process is heated more than the boiling point of the good solvent of the said polyphenylene ether, and the concentration process of obtaining the polymer solution which adjusted the polymer concentration is performed. Production method of polyphenylene ether powder.   The slurry produced by precipitating the polyphenylene ether is further washed with a poor solvent, and solid-liquid separation is performed to obtain wet polyphenylene ether, and then the wet polyphenylene ether is mechanically crushed. 2. A method for producing a polyphenylene ether powder according to 2.   The method for producing a polyphenylene ether powder according to any one of claims 1 to 3, wherein the good solvent of the polyphenylene ether is at least one selected from the group consisting of benzene, toluene, and xylene.   The polyphenylene ether according to any one of claims 1 to 4, wherein the poor solvent of the polyphenylene ether is at least one selected from the group consisting of methanol, ethanol, isopropanol, n-butanol, acetone, methyl ethyl ketone, and water. Powder manufacturing method.   The manufacturing method of the polyphenylene ether powder as described in any one of Claims 1 thru | or 5 with which the poor solvent of the said polyphenylene ether contains 0.05-30 mass% water in the said poor solvent.   The said precipitation tank is equipped with an at least one stage stirring blade selected from the group consisting of an inclined paddle blade, a screw blade, and a ribbon blade, and stirring is performed by the stirring blade in the precipitation step. The manufacturing method of the polyphenylene ether powder as described in any one of these.   The manufacturing method of the polyphenylene ether powder as described in any one of Claims 1 thru | or 7 which uses what is equipped with at least 1 baffle as said precipitation tank.   The precipitation tank includes a draft tube, and the draft tube includes at least one stirrer blade selected from the group consisting of the inclined paddle blade, screw blade, and ribbon blade, and the stirring blade inside the draft tube The method for producing a polyphenylene ether powder according to claim 7 or 8, wherein a lower discharge blade is used and stirring is performed by the stirring blade in the precipitation step.   The precipitation tank further includes a stirring blade that is a ribbon blade on the outside of the draft tube, and the stirring blade outside the draft tube is an upper discharge blade. In the precipitation step, a ribbon outside the draft tube is used. The method for producing a polyphenylene ether powder according to claim 9, wherein stirring is performed with a stirring blade which is a blade.   The manufacturing method of the polyphenylene ether powder as described in any one of Claims 1 thru | or 10 whose liquid temperature in the said precipitation process is 30-63 degreeC.   The method for producing polyphenylene ether powder according to any one of claims 1 to 11, wherein the residence time of the polyphenylene ether in the precipitation tank is 0.25 to 5 minutes. After the precipitation step, further comprising a drying step,
The production of polyphenylene ether powder according to any one of claims 1 to 12, wherein a fine powder ratio (content ratio of particles having a particle diameter of 105 µm or less) of the polyphenylene ether powder after the drying step is 20 mass% or more. Method.   The manufacturing method of the polyphenylene ether powder as described in any one of Claims 1 thru | or 13 whose quantity of the good solvent which the polyphenylene ether powder after the said drying process contains exceeds 0.3 mass%. A polyphenylene ether obtained by the method for producing a polyphenylene ether powder according to any one of claims 1 to 14 is compression-molded to produce a molded body having a density of 0.7 to 1.06 g / cm ³ ,
By re-grinding the molded body, a polyphenylene ether powder having a content of fine particles having a particle size of 105 μm or less of 0.5% by mass or less is obtained.
Production method of polyphenylene ether powder.   The polyphenylene ether according to claim 15, wherein a ratio of the polyphenylene ether powder having a particle size of 105 μm to 5 mm present in the polyphenylene ether powder obtained by regrinding the molded body is 90% by mass or more. Powder manufacturing method.