JP6789009B2 - Method for producing polyphenylene ether powder - Google Patents

Description

The present invention relates to a method for producing a polyphenylene ether (hereinafter, may be simply abbreviated as "PPE") powder.

A modified PPE resin made from PPE can produce a product or part having a desired shape by a molding method such as a melt injection molding method or a melt extrusion molding method. Therefore, it is an electric, electronic, automobile field, and various other industrial materials. It is a plastic material widely used as a material for products or parts in the field.

As a method for producing PPE, a method of oxidatively polymerizing phenols in the presence of copper compounds and amines in a good solvent of PPE is known. In this method, a precipitation step of adding a poor solvent of PPE such as methanol containing water to the PPE solution after polymerization to precipitate PPE particles is performed, and the wet PPE particles obtained in the precipitation step are then carried out. A solid-liquid separation step of separating (solid-liquid separation) into a mixed solvent and wet PPE particles by filtration or the like is performed.

Looking at the reports on conventional PPE solid-liquid separation, there are many techniques for improving particle size such as average particle size and fine powder ratio in the precipitation process, separation failure in the solid-liquid separation process, and filters in the post-process from the drying process. Although it has been reported to improve clogging, etc., the technology for stable discharge from the solid-liquid separator is not disclosed.

For example, in Patent Document 1, by adding water to wet PPE particles and heating them, effective granulation becomes possible, and PPE having a low content of fine particles is produced. Further, in Patent Document 2, the concentration of the polymer solution added to the precipitation tank is made higher than that of the prior art, and the ratio of the poor solvent to the good solvent is kept within a predetermined range, so that the cleaning step and the drying step after the precipitation step are performed. It produces strong and uniform particle size particles that do not become fine particles even in the post-treatment process.

JP-A-2009-221403 Japanese Unexamined Patent Publication No. 2013-256646

However, in the solid-liquid separation step in the conventional method for producing PPE powder, the main purpose is to control the particle size of the precipitated PPE, and the quality is stable and excellent while improving the production efficiency. It was not able to fully meet the demands of the industry such as producing PPE powder.
Therefore, an object of the present invention is to solve various problems in the solid-liquid separation step for preparing wet PPE particles, and to stably produce PPE powder having excellent quality.

In view of the above-mentioned problems, the present inventors separate the PPE particles obtained in the precipitation step into a mixed solvent and wet PPE particles by a solid-liquid separation step, and then discharge the wet PPE particles by a solid-liquid separator. By setting the liquid content within a predetermined range and controlling the apparent density of PPE in the wet PPE particles, due to poor discharge and transfer of the wet PPE particles, and abnormal vibration of the solid-liquid separator. We have found that problems such as emergency stop can be solved advantageously, and have completed the present invention.

That is, the present invention is as follows.
[1] A polymerization step of oxidatively polymerizing a phenol-based compound in a polymerization solution containing a good solvent of polyphenylene ether and a catalyst to obtain a polyphenylene ether mixed solution, the polyphenylene ether mixed solution, and a poor solvent of polyphenylene ether. , Water is added to a precipitation tank having a stirrer and mixed to precipitate polyphenylene ether to obtain a slurry liquid containing polyphenylene ether granules, and the slurry liquid is mixed with wet polyphenylene ether particles and a filtrate. The total content of the good solvent, the poor solvent, and the water in the wet polyphenylene ether particles is 44 to 72 mass with respect to 100% by mass of the wet polyphenylene ether particles. %, The apparent density of the polyphenylene ether in the wet polyphenylene ether particles is 0.2 to 0.5 g / cm ³ , a method for producing a polyphenylene ether powder.
[2] The polyphenylene ether powder according to [1], wherein the content of polyphenylene ether in the wet polyphenylene ether particles is 23.7 to 52.6% by mass with respect to 100% by mass of the wet polyphenylene ether particles. Production method.
[3] The wet polyphenylene ether particles contain a good solvent for the polyphenylene ether, a poor solvent for the polyphenylene ether, and water in a mass ratio of 14.5 to 49:50 to 85: 0.5 to 8. , [1] or [2]. The method for producing a polyphenylene ether powder.
[4] The method for producing a polyphenylene ether powder according to any one of [1] to [3], wherein the average particle size of the wet polyphenylene ether particles is 1000 μm or less.
[5] The method for producing a polyphenylene ether powder according to any one of [1] to [4], wherein the content of the wet polyphenylene ether particles having a particle size of 2000 μm or less is 99.0 to 100% by mass. ..
[6] The method for producing a polyphenylene ether powder according to any one of [1] to [5], further comprising a drying step of drying the wet polyphenylene ether particles.
[7] The method for producing a polyphenylene ether powder according to any one of [1] to [6], wherein the drying temperature is 100 to 180 ° C. in the drying step.
[8] The method for producing a polyphenylene ether powder according to any one of [1] to [7], wherein the content of residual volatile matter in the polyphenylene ether after the drying step is 0.5% by mass or less.

According to the method for producing PPE of the present invention, various problems in the solid-liquid separation step for preparing wet PPE particles can be solved, and PPE powder having excellent quality can be stably produced.

Hereinafter, embodiments for carrying out the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the gist thereof.

[Manufacturing method of polyphenylene ether]
The method for producing polyphenylene ether of the present embodiment is
A polymerization step in which a phenolic compound is oxidatively polymerized in a polymerization solution containing a good solvent and a catalyst for polyphenylene ether to obtain a polyphenylene ether mixed solution.
A precipitation step of adding a polyphenylene ether mixture, a poor solvent for polyphenylene ether, and water to a precipitation tank having a stirrer and mixing them to precipitate polyphenylene ether to obtain a slurry solution containing polyphenylene ether granules. ,
It includes a solid-liquid separation step of separating the slurry liquid into wet polyphenylene ether particles and a filtrate.

Here, in the present embodiment, the total content of the good solvent, the poor solvent, and water in the wet polyphenylene ether particles is 44 to 72% by mass with respect to 100% by mass of the wet polyphenylene ether particles, and the wet polyphenylene. The apparent density of polyphenylene ether in the ether particles is 0.2 to 0.5 g / cm ³ .

The production of PPE of the present embodiment may be a continuous type or a batch type.

Hereinafter, each step in the method for producing PPE of the present embodiment will be described in detail.

(Polymerization process)
In the polymerization step, for example, the phenolic compound is oxidized by aerating an oxygen-containing gas through a polymerization solution containing a good solvent of PPE such as an aromatic solvent, a metal catalyst, a halogen compound, an amine compound and the like. It may be polymerized.

-Polymerization solution-
--Phenolic compounds ---
Examples of the phenolic compound include o-cresol, 2,6-dimethylphenol, 2-ethylphenol, 2-methyl-6-ethylphenol, 2,6-diethylphenol, 2-n-propylphenol, and 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-chlorphenol, 2-methyl-6-phenylphenol, 2-phenylphenol, 2 , 6-Diphenylphenol, 2,6-bis- (4-fluorophenyl) phenol, 2-methyl-6-trilphenol, 2,6-ditrilphenol, 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-phenylphenol, 2,5-diphenylphenol, 2,5-Bis- (4-fluorophenyl) phenol, 2-methyl-5-tolylphenol, 2,5-ditrilphenol, 2,6-dimethyl-3-allylphenol, 2,3,6-triallyl Phenol, 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 can be mentioned.
In particular, 2,6-dimethylphenol, 2,6-diethylphenol, 2,6-diphenylphenol, 2,3,6-trimethylphenol, and 2,5-dimethylphenol are preferable because they are inexpensive and easily available. , 2,6-dimethylphenol, 2,3,6-trimethylphenol are more preferable, and 2,6-dimethylphenol is even more preferable.
The above-mentioned phenolic compound may be used alone or in combination of two or more.
Examples of the combination of two or more types include a combination of 2,6-dimethylphenol and 2,6-diethylphenol, a combination of 2,6-dimethylphenol and 2,6-diphenylphenol, and 2,3,6-. Examples thereof include a combination of trimethylphenol and 2,5-dimethylphenol, and a combination of 2,6-dimethylphenol and 2,3,6-trimethylphenol. The mixing ratio of the phenolic compounds to be combined can be arbitrarily selected.
In addition, the phenolic compound contains a small amount of m-cresol, p-cresol, 2,4-dimethylphenol, 2,4,6-trimethylphenol and the like, which are by-products during production. May be good.

--A good solvent for polyphenylene ether ---
Examples of the good solvent for the polyphenylene ether include aromatic solvents such as benzene, toluene, xylene, ethylbenzene, and styrene. Of these, toluene is preferable from the viewpoint of ease of removing the residual solvent.
In the present embodiment, the good solvent for the polyphenylene ether is preferably one that is substantially incompatible with water.
The above-mentioned good solvent for polyphenylene ether may be used alone or in combination of two or more.

--Catalyst ---
As the catalyst, a catalyst generally used for polymerization of PPE can be used.
Examples of the catalyst include a metal catalyst, a halogen compound, an amine compound, and a catalyst containing a mixture thereof. For example, a transition metal ion as a metal catalyst having an oxidation-reduction ability and an amine capable of complex formation with the transition metal ion. Examples thereof include a mixture composed of a compound, and specific examples thereof include a mixture composed of a copper compound and an amine compound, a mixture composed of a manganese compound and an amine compound, and a mixture composed of a cobalt compound and an amine compound. Of these, a mixture consisting of a copper compound and an amine compound is preferable.

--- Metal catalyst ---
As the metal catalyst in the catalyst, a copper compound is preferable.
As the copper compound, a cuprous compound, a cupric compound, or a mixture thereof can be used. Examples of the cuprous compound include cuprous chloride, cuprous bromide, cuprous sulfate, cuprous nitrate and the like. Examples of the cupric compound include cupric oxide, cupric chloride, cupric bromide, cupric sulfate, cupric nitrate and the like. Of these, cupric oxide, cuprous chloride, cupric chloride, cuprous bromide, and cupric bromide are preferable.
These copper salts are composed of copper oxide (for example, cuprous oxide), copper carbonate carbonate, copper hydroxide and the like, and the corresponding halogen or acid (for example, cuprous oxide and hydrogen halide (or halogen). It may be synthesized at the time of use (from a solution of hydrogen oxide).
These metal catalysts may be used alone or in combination of two or more.

--- Halogen compound ---
The halogen compound is not particularly limited, but specifically, hydrogen chloride, hydrogen bromide, hydrogen iodide, sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide, tetra chloride. Examples thereof include methylammonium, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide and the like. Further, these halogen compounds may be used in the state of a solution using an aqueous solution or an appropriate solvent. Of these, an aqueous solution of hydrogen chloride and an aqueous solution of hydrogen bromide are preferable.
These halogen compounds may be used alone or in combination of two or more.

--- Amine compound ---
Examples of the amine compound include a diamine compound, a secondary monoamine compound, a tertiary monoamine compound and the like. Among them, it is preferable to contain a diamine compound, and more preferably to contain a diamine compound, a secondary monoamine compound, and a tertiary monoamine compound.
The amine compound may be used alone or in combination of two or more.

（式（１）中、Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４は、それぞれ独立して、水素原子、炭素数１〜６の直鎖状又は分岐鎖状のアルキル基であり、全てが同時に水素原子ではない。Ｒ_５は、炭素数２〜５の直鎖状又は分岐鎖状のアルキレン基を示す。） As the diamine compound, a diamine compound represented by the following general formula (1) is preferable.
As the catalyst, for example, a catalyst containing a copper compound, a halogen compound and a diamine compound represented by the following general formula (1) may be used. By using such a catalyst, there is a tendency that the polymerization rate can be further increased and the polymerization time can be further shortened. Further, by adjusting the amount of catalyst, the amount of oxygen blown in, the polymerization time, etc., the molecular weight after polymerization tends to be more easily adjusted.

(In the formula (1), R ₁ , R ₂ , R ₃ and R ₄ are independently hydrogen atoms and linear or branched alkyl groups having 1 to 6 carbon atoms, all at the same time. not a hydrogen atom .R ₅ denotes a straight or branched alkylene group having 2 to 5 carbon atoms.)

The diamine compound represented by the above general formula (1) is not particularly limited, but specifically, 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, N-i-propylethylenediamine, N, N'-di-i-propylethylenediamine, Nn-butylethylenediamine, N, N'-di-n-butylethylenediamine, N-i-butylethylenediamine, N, N'-di-i-butylethylenediamine, 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'- Examples thereof include tetramethyl-1,4-diaminobutane, N, N, N', N'-tetramethyl-1,5-diaminopentane and the like. Among them, in the formula (1), a diamine compound wherein R ₅ is alkylene group having 2 or 3 carbon atoms are preferred.
The diamine compound may be used alone or in combination of two or more.
The amount of the diamine compound used is not particularly limited, but is preferably 0.01 to 10 mol with respect to 100 mol of the phenolic compound.

The tertiary monoamine compound is not particularly limited, and specific examples thereof include an aliphatic tertiary amine containing an alicyclic tertiary amine. Such a tertiary monoamine compound is not particularly limited, but specifically, trimethylamine, triethylamine, tripropylamine, tributylamine, triisobutylamine, dimethylethylamine, dimethylpropylamine, allyldiethylamine, N-butyldimethylamine. , Diethylisopropylamine, N-methylcyclohexylamine and the like.
The above-mentioned tertiary monoamine compound may be used alone or in combination of two or more.
The amount of the tertiary monoamine compound used is not particularly limited, but is preferably 15 mol or less with respect to 100 mol of the phenolic compound.

The whole amount of the tertiary monoamine compound may be added before the polymerization, or a part thereof may be added before the polymerization and further sequentially added during the polymerization. Further, the tertiary monoamine may be added to the polymerization solution at the same time as the start of the polymerization after being mixed with the phenolic compound.

The secondary monoamine compound is not particularly limited, and specific examples thereof include a secondary aliphatic amine. The secondary aliphatic amine is not particularly limited, but specifically, dimethylamine, diethylamine, di-n-propylamine, di-i-propylamine, di-n-butylamine, di-i-butylamine, and the like. Examples thereof include di-t-butylamine, dipentylamine, dihexylamine, dioctylamine, didecylamine, dibenzylamine, methylethylamine, methylpropylamine, methylbutylamine, cyclohexylamine and the like.
Further, as the secondary monoamine compound, a secondary monoamine compound containing an aromatic may be used. The secondary monoamine compound containing an aromatic is not particularly limited, but specifically, N-phenylethanolamine, N-phenylethanolamine, N-phenylpropanolamine, N- (m-methylphenyl) ethanolamine, etc. N- (substituted or unsubstituted phenyl) alkanolamines such as N- (p-methylphenyl) ethanolamine, N- (2', 6'-dimethylphenyl) ethanolamine, N- (p-chlorophenyl) ethanolamine; Examples thereof include N-hydrocarbon-substituted anilines such as N-ethylaniline, N-butylaniline, N-methyl-2-methylaniline, N-methyl-2,6-dimethylaniline and diphenylamine;
The secondary monoamine compound may be used alone or in combination of two or more.
The amount of the secondary monoamine compound used is not particularly limited, but is preferably 15 mol or less with respect to 100 mol of the phenolic compound.

Further, a surfactant which has been conventionally known to have an effect of improving the polymerization activity may be added to the polymerization solution.
Examples of the surfactant include trioctylmethylammonium chloride known under the trade names of Aliquat 336 (manufactured by Henkel) and CapRiquat (manufactured by Dojin Chemical Laboratory Co., Ltd.).
The amount of the surfactant used is preferably in the range not exceeding 0.1% by mass with respect to the total amount of the polymerization solution.

--Aeration of oxygen-containing gas ---
In the polymerization step, the phenolic compound may be polymerized while aerating an oxygen-containing gas. The start time of aeration of the oxygen-containing gas is not particularly limited, but in the preparation of the polymerization solution, after introducing any of a phenolic compound, an aromatic solvent, and a catalyst into the reactor, the aeration of the oxygen-containing gas is started. Is preferable.

The oxygen-containing gas is not particularly limited, and specifically, a mixture of oxygen and an arbitrary inert gas, air, or a mixture of air and an arbitrary inert gas can be used. The inert gas is not particularly limited, but specifically, any gas can be used as long as it does not have a large effect on the polymerization reaction. A typical inert gas is nitrogen.

The aeration amount of the oxygen-containing gas in the polymerization step is preferably 3 to 14 L / min, more preferably 6 to 13 L, with respect to 1 kg of the phenolic compound to be subjected to the polymerization reaction, from the viewpoint of more efficient polymerization. / Minute.

In the production method of this embodiment, the polymerization method of PPE is not particularly limited. Examples of the method for polymerizing PPE include a method for oxidatively polymerizing 2,6-xylenol using a complex of a cuprous salt and an amine described in US Pat. No. 3,306,874 as a catalyst, US Pat. No. 3,306,875, No. The methods described in the specification of No. 3257357, the specification of No. 3257358, the Japanese Patent Publication No. 52-17880, the Japanese Patent Application Laid-Open No. 50-51197, the Japanese Patent Application Laid-Open No. 63-152628, and the like are preferable.

Examples of the PPE polymerization method in the present embodiment include a precipitation-precipitation polymerization method and a solution polymerization method. The production method of this embodiment is preferably a production method for precipitating PPE obtained by the solution polymerization method. The solution polymerization method is a polymerization method in which polymerization is carried out in a good solvent of PPE and no precipitate is precipitated during the polymerization. In the solution polymerization method, all PPE molecules are in a dissolved state, and the molecular weight distribution tends to be wide.

After the above polymerization step, a chelating agent solution is added to the PPE mixed solution, the metal catalyst is extracted to the chelating agent solution side, and the liquids are separated into the aromatic solvent phase and the chelating agent solution phase and mixed with PPE. A catalyst extraction step for removing the metal catalyst in the liquid may be provided. In the catalyst extraction step, water can be further added to the PPE mixed solution after the chelating agent solution is added to separate the liquids, and the liquid separation is repeated to further extract the catalyst. In the present specification, the PPE mixed solution after the catalyst is extracted in the catalyst extraction step may also be referred to as "polyphenylene ether mixed solution" or "PPE mixed solution".

In the catalyst extraction step, the chelating agent solution is added to the PPE mixture after the polymerization step and stirred to extract the metal catalyst used as the catalyst to the chelating agent solution side, and chelate with the polyphenylenelter mixture. The metal catalyst in the PPE mixture can be removed by separating the agent solution into liquids.
Examples of the chelating agent used in the chelating agent solution include acids such as hydrochloric acid and acetic acid; ethylenediaminetetraacetic acid (EDTA) and its salt; nitrilotriacetic acid and its salt; and the like. The chelating agent may be added alone, but the chelating agent is dissolved in a solvent such as water, which has a low dissolving ability of PPE and is phase-separated from an aromatic solvent which is a good solvent for PPE. It is preferable to add it as an aqueous solution or the like. When an aqueous chelate solution is used, the metal catalyst deactivated by binding to the chelating agent is extracted into the aqueous phase, so that the PPE contained in the organic phase and the metal catalyst can be separated.

In the above catalyst extraction step, the metal catalyst may be further extracted by repeating the step of adding water to the PPE mixed solution after adding the chelating agent solution and separating the liquids. ..

The two-phase separation in the catalyst extraction step and the washing step described later may be separated by static separation or may use a liquid separator.

After the polymerization step or the catalyst extraction step, a concentration step for adjusting the concentration of PPE in the PPE mixture after the polymerization step may be provided by evaporating a part of the good solvent. In the present specification, the PPE mixed solution after concentrating PPE in the concentration step may also be referred to as "polyphenylene ether mixed solution" or "PPE mixed solution". One of the catalyst extraction step and the concentration step may be provided, or both may be provided.
The PPE concentration in the PPE mixed solution after concentration is preferably more than 30% by mass, and preferably 50% by mass or less. The PPE concentration in the PPE mixed solution is more preferably 48% by mass or less, and further preferably 45% by mass or less.
If the PPE concentration in the PPE mixture is 30% by mass or less, the dispersibility of the PPE mixture becomes too high in the precipitation tank, and fine powder increases, which is not preferable. When the PPE concentration in the PPE mixture exceeds 50% by mass, the dispersibility of the PPE mixture in the precipitation tank is lowered, and the poorly dispersed PPE mixture adheres to the wall surface, the stirring shaft baffle, etc. and becomes a scale. .. Further, the liquid viscosity becomes high and the equipment cost of peripheral equipment such as a pump becomes large, which is not preferable.

(Precipitation process)
In the production method of the present embodiment, after the polymerization step, the PPE mixture solution optionally further after the catalyst extraction step and the concentration step is solidified by mixing with a poor solvent for PPE such as methanol and water to solidify the PPE granules. It has a precipitation step of obtaining a slurry liquid containing a substance.
In the above-mentioned precipitation step, for example, after concentrating as necessary, a PPE mixed solution contains a PPE-poor solvent such as ketones having 1 to 10 carbon atoms, alcohols having 1 to 10 carbon atoms, and water. Is added and mixed to precipitate PPE, and a slurry liquid containing PPE granules can be obtained.

-Poor solvent for polyphenylene ether-
Examples of the poor solvent for PPE include polar solvents such as ketones having 1 to 10 carbon atoms and alcohols having 1 to 10 carbon atoms.
Examples of the polar solvent include methanol, ethanol, 1-propanol, 2-propanol, n-butanol, 2-butanol, pentanol, hexanol, ethylene glycol, acetone, methyl ethyl ketone and the like. Of these, methanol, ethanol, 2-propanol, n-butanol, 2-butanol, acetone, and methyl ethyl ketone are preferable from the viewpoint of availability. Further, as the polar solvent, an alcohol having 1 to 10 carbon atoms is also preferable.
The polar solvent may be used alone or in combination of two or more.

In the precipitation step, a precipitation tank having a stirrer may be used.
As the precipitation tank used in the precipitation step, it is preferable that the precipitation tank is provided with at least one stage of stirring blade selected from an inclined paddle blade, a screw blade, and a ribbon blade. Further, from the viewpoint of enhancing the mixing property, it is preferable that the stirring blade is provided with at least one baffle and the stirring blade is discharged downward.

In the precipitation step, the amount of the poor solvent added to the polyphenylene ether is adjusted from the viewpoint of reducing the content of residual volatile matter in the polyphenylene ether after the drying step. It is preferably 50 to 200% by mass, more preferably 60 to 180% by mass, based on 100% by mass of the good solvent.

The temperature of the PPE mixed solution immediately before being added to the precipitation tank is preferably 60 to 100 ° C. The temperature of the PPE mixed solution is more preferably 90 ° C. or lower, and even more preferably 80 ° C. or lower. Further, it is more preferably 65 ° C. or higher.
If the temperature of the PPE mixture is less than 60 ° C., the dispersibility of the PPE mixture in the precipitation tank is lowered, and the poorly dispersed PPE mixture adheres to the wall surface, the stirring shaft, the baffle, etc., and becomes a scale. In addition, the liquid viscosity becomes high and the equipment cost of peripheral equipment such as a pump becomes large, which is not preferable. If the temperature of the PPE mixed solution exceeds 100 ° C., the dispersibility of the PPE mixed solution becomes too high in the precipitation tank, and fine powder increases, which is not preferable.

(Solid-liquid separation process)
The production method of the present embodiment includes a solid-liquid separation step of separating the slurry liquid (suspension) into wet polyphenylene ether particles and a filtrate.
In the solid-liquid separation step, the slurry liquid obtained in the precipitation step may be solid-liquid separated to obtain wet PPE particles. At this time, a poor solvent may be added to the slurry liquid to appropriately dilute the slurry liquid. Good. Further, the wet PPE particles obtained by solid-liquid separation of the slurry liquid obtained in the precipitation step may be washed once or a plurality of times with a poor solvent to obtain wet PPE particles.
Examples of the PPE antisolvent that can be used for diluting the above-mentioned slurry liquid and washing the above-mentioned wet PPE include those that can be used in the precipitation step.

The device used for solid-liquid separation is not particularly limited, but is not limited to a centrifuge (vibration type, screw type, decanter type, basket type, etc.), vacuum filter (drum type filter, belt filter, etc.). A rotary vacuum filter, a young filter, a nutche, etc.), a filter press, a roll press, etc. can be used.

The reduced pressure filtration time for solid-liquid separation is not particularly limited, but is preferably 10 to 30 seconds, preferably 15 to 25 seconds, for example, when a glass vacuum filter is used. Is even more preferable.

Here, in the production method of the present embodiment, the total content of the good solvent of polyphenylene ether, the poor solvent of polyphenylene ether and water in the wet polyphenylene ether particles is 44 to 100% by mass with respect to 100% by mass of the wet polyphenylene ether particles. It is 72% by mass, preferably 50 to 71% by mass, and even more preferably 55 to 68% by mass.
When it is 44% by mass or more, it is possible to reduce the proportion of particles scattered during the drying treatment, and it is possible to effectively suppress problems such as scattering of fine particles and clogging of the filter. When it is 72% by mass or less, the wet polyphenylene ether particles can be discharged more stably than the solid-liquid separator.

At this time, from the viewpoint of ensuring that the wet polyphenylene ether particles have an appropriate cohesiveness, the wet polyphenylene ether particles contain a good solvent for polyphenylene ether, a poor solvent for polyphenylene ether, and water from 14.5 to 49:50. It is preferably contained in a mass ratio of ~ 85: 0.5 to 8, and more preferably contained in a mass ratio of 15 to 40:50 to 80: 1 to 7.

Further, the content of polyphenylene ether in the wet polyphenylene ether particles is preferably 23.7 to 52.6% by mass, preferably 24.1 to 51.9% by mass, based on 100% by mass of the wet polyphenylene ether particles. More preferably, it is 24.9 to 50.8% by mass.

In this case, in the manufacturing method of this embodiment, the apparent density of the polyphenylene ether in a wet polyphenylene ether particles is a 0.2-0.5 g / cm ^3, is 0.2-0.4 g / cm ³ It is preferable, and more preferably 0.22 to 0.38 g / cm ³ .

In the present embodiment, the total content of the good solvent of the polyphenylene ether, the poor solvent of the polyphenylene ether and the water in the wet polyphenylene ether particles is kept within the above range, and the appearance of the polyphenylene ether in the wet polyphenylene ether particles is apparent. In order to keep the density within the above range, problems such as poor discharge and poor transportation of wet PPE particles, emergency stop due to abnormal vibration of the solid-liquid separator, etc. are solved, and stable and excellent quality PPE powder is produced. It becomes possible.
Further, in the present embodiment, the wet PPE has an appropriate cohesiveness to satisfy the above requirements, and the wet PPE is easily peeled from the container (for example, a glass filter) at the time of solid-liquid separation, and the wet PPE is easily solidified. It is possible to transfer from the container at the time of liquid separation to another container (for example, an aluminum dish).

The average particle size of the wet PPE particles of the present embodiment is preferably 1000 μm or less, more preferably 950 μm or less.
If the average particle size of the wet PPE is more than 1000 μm, troubles such as poor peeling and discharge of wet PPE particles and emergency stop due to abnormal vibration of the solid-liquid separator may occur during operation of the solid-liquid separator. is there.
The average particle size of PPE is the volume average particle size by a wet method (methanol solvent) using a laser diffraction / scattering type particle size distribution measuring device manufactured by Shimadzu Corporation, which is a particle size distribution meter of the laser diffraction / scattering method. Can be measured as. From the cumulative curve of the particle size distribution of the volume average particle size, the particle size (median diameter) corresponding to the median cumulative value can be set as the average particle size (μm).

The content of particles having a particle size of 2000 μm or less in the wet PPE is preferably 99.0% by mass or more, more preferably 99.5% by mass or more, and most preferably 100% by mass.
When it is 99.0% by mass or more, it is possible to prevent a discharge defect or the like during transportation to the next step.
The content of particles having a particle size of 2000 μm or less in the wet PPE can be measured by using a laser diffraction / scattering type particle size distribution measuring device manufactured by Shimadzu Corporation, which is a particle size distribution meter of the laser diffraction / scattering method. .. The content (mass%) of particles having a particle size of 2000 μm or less in PPE powder obtained from the cumulative curve of the particle size distribution of the volume average particle size can be calculated.

In the present embodiment, by controlling the average particle size of the wet polyphenylene ether particles after solid-liquid separation to 1000 μm or less, the crushing process is bypassed, the installation space of the crusher is reduced, and the labor for maintenance is reduced. It is also possible to reduce the running cost.

Subsequently, in the method for producing the polyphenylene ether powder of the present embodiment, the wet polyphenylene ether particles after the solid-liquid separation step are dried (drying step).

The drying step may be provided after pulverization or may be provided without pulverization.

The drying temperature is preferably 60 ° C. or higher, more preferably 80 ° C. or higher, further preferably 120 ° C. or higher, more preferably 140 ° C. or higher, and particularly preferably 150 ° C. or higher. Further, from the viewpoint that the melt phenomenon is unlikely to occur in PPE, the temperature is preferably 180 ° C. or lower, more preferably 175 ° C. or lower, and even more preferably 170 ° C. or lower.
When the wet PPE is dried at a temperature of 60 ° C. or higher, the content of a good solvent (for example, aromatic hydrocarbon) in the polyphenylene ether particles can be efficiently reduced.

In order to increase the yield of PPE after the drying process, a method of raising the drying temperature, a method of aerating an inert gas such as nitrogen during drying, a method of increasing the degree of vacuum during drying, and a method of stirring during drying are performed. The method or the like is preferable.
For 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 amount of processing can be increased and the productivity can be maintained high.

The content of residual volatile matter in the polyphenylene ether after the drying process should be from the viewpoint of the working environment in the post-processing and prevent the residual volatile matter gas in the extrusion process from backflowing to maintain the stability of operation. It is preferably 0.5% by mass or less, and more preferably 0.4% by mass or less from the viewpoint of being able to produce.
The residual volatile matter refers to the amount of change in the mass of PPE before and after the operation of vacuum-drying the polyphenylene ether after the drying step under the conditions of a temperature of 180 ° C. and a pressure of 10 torr for 120 minutes.

Hereinafter, the PPE obtained by the production method of the present embodiment will be described in detail.

式（２）中、Ｒ_１、Ｒ_２、Ｒ_３、及びＲ_４は、それぞれ独立して、水素原子、ハロゲン原子、炭素数１〜７のアルキル基、フェニル基、ハロアルキル基、アミノアルキル基、炭化水素オキシ基、及び少なくとも２個の炭素原子がハロゲン原子と酸素原子とを隔てているハロ炭化水素オキシ基からなる群より選ばれるいずれかである。 [Polyphenylene ether powder]
The polyphenylene ether of the polyphenylene ether powder obtained by the production method of the present embodiment is a homopolymer and / or a copolymer containing a repeating unit structure represented by the following general formula (2).
In the present specification, the PPE obtained by the production method of the present embodiment may be referred to as the PPE of the present embodiment.

In formula (2), R ₁ , R ₂ , R ₃ , and R ₄ are independently hydrogen atoms, halogen atoms, alkyl groups having 1 to 7 carbon atoms, phenyl groups, haloalkyl groups, and aminoalkyl groups, respectively. It is one selected from the group consisting of a hydrocarbon oxy group and a halohydrocarbon oxy group in which at least two carbon atoms separate a halogen atom from an oxygen atom.

The homopolymer of PPE is not particularly limited, but specifically, poly (2,6-dimethyl-1,4-phenylene) ether and poly (2-methyl-6-ethyl-1,4-phenylene) are used. ) Ether, poly (2,6-diethyl-1,4-phenylene) ether, poly (2-ethyl-6-n-propyl-1,4-phenylene) ether, poly (2,6-di-n-propyl) -1,4-phenylene) ether, poly (2-methyl-6-n-butyl-1,4-phenylene) ether, poly (2-ethyl-6-isopropyl-1,4-phenylene) ether, poly (2) Examples thereof include -methyl-6-hydroxyethyl-1,4-phenylene) ether and poly (2-methyl-6-chloroethyl-1,4-phenylene) ether. Among these, poly (2,6-dimethyl-1,4-phenylene) ether is preferable from the viewpoint that the raw material is inexpensive and easily available.

The above-mentioned copolymer of PPE is not particularly limited, but specifically, a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol, and 2,6-dimethylphenol and o-cresol. Examples thereof include a copolymer of 2,6-dimethylphenol, 2,3,6-trimethylphenol and o-cresol. Among these, a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol is preferable from the viewpoint that the raw material is inexpensive and easily available.

The reduced viscosity of PPE of the present embodiment measured at 30 ° C. using a 0.5 g / dL chloroform solution is 0.25 to 0.85 dL / g, more preferably 0.25 to 0.75 dL / g. is there.
When the reduced viscosity is 0.20 dL / g or more, more sufficient mechanical properties can be exhibited. Further, when the reduced viscosity is 0.85 dL / g or less, the solution viscosity at the time of polymerization does not become too high, the capacity of the peripheral equipment of the polymerization tank can be appropriately controlled, the post-treatment is easy, and the processability is easy. Will also be good.
For the reduced viscosity, a chloroform solution of 0.5 g / dL of PPE is prepared, and the chloroform solution is used as a sample to determine the reduced viscosity η _sp / c (dL / g) at 30 ° C. using an Ubbelohde viscous tube. be able to.

Hereinafter, the present embodiment will be specifically described with reference to Examples and Comparative Examples, but the scope of the present embodiment is not limited to these Examples.
First, the methods for measuring physical properties, properties, etc. applied to Production Examples, Examples, and Comparative Examples are shown below.

<Measurement of good solvent, poor solvent, and water content in wet PPE particles>
Wet PPE obtained in the solid-liquid separation step was analyzed by gas chromatography (manufactured by Shimadzu Corporation, GC-2010 type) together with a FID detector by the internal standard calibration curve method using mesitylene as an internal standard substance. , Good solvent and poor solvent in wet PPE were quantified. For gas chromatography, a capillary column (HR-1 manufactured by Shinwa Kako Co., Ltd.) was attached, and a column heating program (holding at 40 ° C. for 1 minute, then rising to 200 ° C. at a heating rate of 30 ° C. per minute, and then 200 ° C. (Holding for 1 minute) was set and the measurement was performed.
The water content was quantified using a Karl Fischer titer moisture meter (manufactured by Mitsubishi Chemical Corporation, CA-200). Specifically, the amount of electricity when iodine is generated from iodide ions at the anode by electrolysis in the electrolytic solution (anodic) using a solution containing iodide ions, sulfur dioxide, and alcohol as the electrolytic solution. Was measured, and the mass of water contained was calculated from the amount of electricity according to Faraday's law.
From the masses of the good solvent, the poor solvent, and water calculated as described above and the mass of the wet PPE, the contents of the good solvent, the poor solvent, and water in the wet PPE particles were calculated.

<Measurement of average particle size of wet PPE>
With respect to the obtained wet PPE particles, the volume average particle diameter of the wet PPE particles was measured using a laser diffraction type particle size distribution measuring device (manufactured by Shimadzu Corporation, SALD-3100 type).
From the cumulative curve of the particle size distribution of the volume average particle size, the particle size (median diameter) corresponding to the median cumulative value was defined as the average particle size (μm).

<Content rate of particles with a particle size of 2000 μm or less>
With respect to the obtained wet PPE, the content of particles having a particle size of 2000 μm or less in the wet PPE was measured using a laser diffraction type particle size distribution measuring device (manufactured by Shimadzu Corporation, SALD-3100 type).
The content (mass%) of the particles having a particle size of 2000 μm or less in the wet PPE particles obtained from the cumulative curve of the particle size distribution of the volume average particle size was calculated.

<Measurement of apparent density>
The volume of the obtained wet PPE particles in a glass filter was measured, and then the wet PPE was put into a vacuum dryer together with the glass filter, the temperature of the vacuum dryer was set to 120 ° C., and the pressure was reduced to 10 torr. Then, vacuum drying was performed for 120 minutes. The apparent density of PPE (g / cm ³ ) in the wet PPE particles was calculated from the volume of the wet PPE particles and the mass of the sample after drying.

<Confirmation of peelability>
When the obtained wet PPE particles were transferred from the glass filter to the aluminum dish, the state of peeling of the wet PPE particles from the glass filter was visually observed, and the peelability was evaluated according to the following evaluation criteria.
◯: There is no lump in the wet PPE, and no wet PPE particles adhere to the filter surface of the glass filter.
Δ: There are no lumps in the wet PPE, but wet PPE particles are attached to the filter surface of the glass filter.
X: There are lumps in the wet PPE, and wet PPE particles are also attached to the filter surface of the glass filter.

<Measurement of residual volatilization of dried PPE>
Weigh the PPE after the drying process into an aluminum dish, put the sample together with the aluminum dish in a vacuum dryer, set the temperature of the vacuum dryer to 180 ° C, and vacuum dry for 120 minutes with the pressure reduced to 10 torr. It was. The residual volatile content (mass%) in the dried PPE was calculated from the change in the mass of the sample before and after drying.

<Measurement of reduced viscosity>
The reduced viscosity (η _sp / c) (dL / g) at 30 ° C. of the 0.5 g / dL chloroform solution of PPE after the drying step was determined with an Ubbelohde viscous tube.

<Manufacturing example 1>
0.5 L / min in a 40 liter jacketed polymerization tank equipped with a spudger for introducing oxygen-containing gas at the bottom of the polymerization tank, stirring turbine blades and baffles, and a reflux condenser on the vent gas line at the top of the polymerization tank. 4.57 g of cupric oxide, 24.18 g of 47 mass% hydrogen bromide solution, 11.00 g of di-t-butylethylenediamine, 62.72 g of di-n-butylamine, while blowing nitrogen gas at a flow rate. 149.92 g of butyldimethylamine, 20.65 kg of toluene, and 3.12 kg of 2,6-dimethylphenol were added, and the mixture was stirred until a uniform solution was obtained and the internal temperature of the polymerization tank reached 25 ° C.
Next, dry air was introduced into the polymerization tank at a rate of 32.8 L / min from a sparger to start polymerization. Dry air was aerated for 140 minutes to give a polymerization mixture. During the polymerization, the internal temperature was controlled to be 40 ° C. The polymerization solution at the end of the polymerization was in a uniform solution state.
The aeration of dry air was stopped, and 10 kg of a 2.5 mass% aqueous solution of ethylenediaminetetraacetic acid tetrasodium salt (manufactured by Dojin Chemical Laboratory) was added to the polymerized PPE mixture. The PPE mixed solution was stirred at 70 ° C. for 150 minutes, then allowed to stand for 20 minutes, and the organic phase and the aqueous phase were separated by liquid-liquid separation, and the organic phase was recovered. The PPE concentration in the obtained PPE polymerization solution was 13.1% by mass. The obtained PPE polymerization solution was used as a polymer solution (1).
The obtained polymer solution (1) was placed in a stirring tank with a jacket, and a heat medium at 120 ° C. was passed through the jacket for heating. The generated toluene-based vapor was cooled by a condenser, and the condensed toluene was extracted from the system and concentrated until the polymer concentration in the stirring tank reached 35% by mass. This operation was repeated to prepare 10 kg of a polymer solution having a polymer concentration of 35% by mass.
After the organic phase is brought to room temperature, a draft tube provided by adding four baffles to the outside of the draft tube, as shown in Example 1 of International Publication No. 2003/06449, a precipitation tank with a jacket provided with four inclined paddle wings. Was used. The volume of the liquid retained in this precipitation tank was 1232 mL. 500 g of toluene and 500 g of methanol were charged in the precipitation tank, and the mixture was stirred at 1700 rpm. An overflow line was provided in the stirring tank so that when the amount of the internal liquid exceeds 1232 mL, the internal liquid overflows and is discharged to the outside of the tank. Regarding the position of the feed line, the PPE mixed liquid supply port is installed inside the draft tube above the liquid level so that it is added to the place where it flows toward the bottom of the tank during the circulating flow, and the poor solvent supply port and the poor solvent supply port are installed. The water supply port was installed above the liquid level between the draft tube and the wall of the precipitation tank. Three liquid addition nozzles are installed above the liquid level, polymer solution (1) from the first nozzle (PPE mixed liquid supply port), methanol from the second nozzle (poor solvent supply port), and third nozzle (poor solvent supply port). Water was added into the tank from the water supply port). The temperature immediately before the addition of the polymer solution (1) was 65 ° C. The stirrer continued to rotate at 1700 rpm. The slurry liquid overflowing from the precipitation tank and discharged was received by the washing tank to prepare the slurry liquid.

Hereinafter, in each of the examples and the comparative examples, the following operations were performed while using the conditions shown in Table 1. Details of the operations in each example will be described later.
A part of the obtained slurry liquid is put into a glass filter (Buchnaroth type) and filtered under reduced pressure using an aspirator (EYELA A-3S type manufactured by Tokyo Science Instruments Co., Ltd.) to obtain wet PPE particles. Obtained.
A mixed solution of toluene, methanol, and water was added to the obtained wet PPE particles, and the mixture was stirred and then filtered again under reduced pressure to obtain wet PPE particles.
Then, the wet PPE particles were placed in a vacuum dryer and held at a temperature of 120 ° C. and a pressure of 1 mmHg for 1.5 hours to obtain a dried polyphenylene ether powder. The reduced viscosity of the obtained PPE powder was 0.502 dL / g in all the examples.

[Example 1]
230 g of the slurry liquid obtained in Production Example 1 was put into a glass filter and filtered under reduced pressure for 25 seconds using an aspirator. To 30 g of the obtained wet PPE particles, 207 g of a washing liquid (methanol 200 g, toluene 5 g, water 2 g) was added, stirred, and then filtered again under reduced pressure for 25 seconds to obtain wet PPE particles. This washing operation was repeated twice in total to prepare 150 g of wet PPE particles of Example 1. Each measurement was carried out on the obtained wet PPE particles by the method described above. Detailed conditions and results are shown in Table 1.

[Example 2]
Wet PPE particles were obtained in the same manner as in Example 1 except that the time of vacuum filtration in the filtration of the slurry liquid and the filtration during washing was set to 20 seconds. Each measurement was carried out on the obtained wet PPE particles by the method described above. Detailed conditions and results are shown in Table 1.

[Example 3]
Wet PPE particles were obtained in the same manner as in Example 1 except that the time of vacuum filtration in the filtration of the slurry liquid and the filtration during washing was set to 15 seconds. Each measurement was carried out on the obtained wet PPE particles by the method described above. Detailed conditions and results are shown in Table 1.

[Example 4]
Wet PPE particles were obtained in the same manner as in Example 1 except that the time of vacuum filtration in the filtration of the slurry liquid and the filtration during washing was set to 10 seconds. Each measurement was carried out on the obtained wet PPE particles by the method described above. Detailed conditions and results are shown in Table 1.

[Example 5]
Wet PPE particles were obtained in the same manner as in Example 1 except that the time of vacuum filtration in the filtration of the slurry liquid and the filtration during washing was set to 30 seconds. Each measurement was carried out on the obtained wet PPE particles by the method described above. Detailed conditions and results are shown in Table 1.

[Comparative Example 1]
Wet PPE particles were obtained in the same manner as in Example 1 except that the time of vacuum filtration in the filtration of the slurry liquid and the filtration during washing was set to 60 seconds. Each measurement was carried out on the obtained wet PPE particles by the method described above. Detailed conditions and results are shown in Table 1.

[Comparative Example 2]
Wet PPE particles were obtained in the same manner as in Example 1 except that the time of vacuum filtration in the filtration of the slurry liquid and the filtration during washing was set to 5 seconds. Each measurement was carried out on the obtained wet PPE particles by the method described above. Detailed conditions and results are shown in Table 1.

[Comparative Example 3]
Wet PPE particles were obtained in the same manner as in Example 1 except that the time of vacuum filtration in the filtration of the slurry liquid and the filtration during washing was set to 180 seconds. Each measurement was carried out on the obtained wet PPE particles by the method described above. Detailed conditions and results are shown in Table 1.

According to the method for producing polyphenylene ether powder of the present invention, various problems in the solid-liquid separation step for preparing wet polyphenylene ether particles can be solved, and a polyphenylene ether powder having excellent quality can be stably produced.
The polyphenylene ether resin composition containing the polyphenylene ether powder obtained by the method for producing the polyphenylene ether powder of the present invention can be used for automobile parts, heat-resistant parts, electronic device parts, industrial parts, coating agents, insulating coatings and the like. As a material, it has industrial potential.

Claims (8)

A polymerization step in which a phenolic compound is oxidatively polymerized in a polymerization solution containing a good solvent and a catalyst for polyphenylene ether to obtain a polyphenylene ether mixed solution.
Precipitation step of adding the polyphenylene ether mixture, a poor solvent of polyphenylene ether, and water to a precipitation tank having a stirrer and mixing them to precipitate polyphenylene ether to obtain a slurry solution containing polyphenylene ether granules. When,
The solid-liquid separation step of separating the slurry liquid into wet polyphenylene ether particles and a filtrate is included.
The total content of the good solvent, the poor solvent, and the water in the wet polyphenylene ether particles is 44 to 72% by mass with respect to 100% by mass of the wet polyphenylene ether particles.
A method for producing a polyphenylene ether powder, which comprises an apparent density of polyphenylene ether in the wet polyphenylene ether particles of 0.2 to 0.5 g / cm ³ . The method for producing a polyphenylene ether powder according to claim 1, wherein the content of polyphenylene ether in the wet polyphenylene ether particles is 23.7 to 52.6% by mass with respect to 100% by mass of the wet polyphenylene ether particles. Claimed that the wet polyphenylene ether particles contain a good solvent of the polyphenylene ether, a poor solvent of the polyphenylene ether, and water in a mass ratio of 14.5 to 49:50 to 85:0.5 to 8. The method for producing a polyphenylene ether powder according to 1 or 2. The method for producing a polyphenylene ether powder according to any one of claims 1 to 3, wherein the average particle size of the wet polyphenylene ether particles is 1000 μm or less. The method for producing a polyphenylene ether powder according to any one of claims 1 to 4, wherein the content of the particles having a particle size of 2000 μm or less in the wet polyphenylene ether particles is 99.0 to 100% by mass. The method for producing a polyphenylene ether powder according to any one of claims 1 to 5, further comprising a drying step of drying the wet polyphenylene ether particles. The method for producing a polyphenylene ether powder according to any one of claims 1 to 6, wherein in the drying step, the drying temperature is 100 to 180 ° C. The method for producing a polyphenylene ether powder according to any one of claims 1 to 7, wherein the content of residual volatile matter in the polyphenylene ether after the drying step is 0.5% by mass or less.