JP6889085B2 - Method for producing polyarylene sulfide - Google Patents

Description

The present invention relates to a method for producing polyarylene sulfide.

Various polymers are widely used as important industrial materials in various applications such as various industrial materials, textile materials, and building materials. For example, polyarylene sulfide (PAS) represented by polyphenylene sulfide (PPS), polyketone sulfide (PKS), polysulfone sulfide (PSS) and the like has heat resistance, chemical resistance, flame retardancy, mechanical strength, electrical properties, etc. It is an engineering plastic with excellent dimensional stability, etc., and can be molded into various molded products, films, sheets, fibers, etc. by general melt processing methods such as extrusion molding, injection molding, and compression molding. It is widely used in a wide range of technical fields such as equipment, automobile equipment, and packaging materials.

As a method for producing such a polymer, for example, a method using a batch method can be mentioned, while a method using a continuous method has also been proposed. For example, Patent Documents 1 to 3 disclose a PAS continuous polymerization apparatus in which pressure-resistant polymerization cans are connected in series and a reaction solution is transferred between the polymerization cans by a pressure difference, and a continuous polymerization method using the apparatus. ing.

Further, Patent Documents 4 to 7 disclose a method for recovering granular PAS. For example, Patent Document 4 discloses a method of recovering PAS particles by adding a phase separation agent to a polymerization reaction mixture of PAS forming a molten phase and then lowering the temperature. Patent Document 5 further discloses a method for producing PAS particles by strictly controlling the cooling conditions of the polymerization reaction mixture. Patent Document 6 discloses a method of recovering PAS particles by adding water to a polymerization reaction mixture and then slowly cooling the mixture. Patent Document 7 discloses a method for producing PAS particles by producing PAS by a multi-step method, mixing the PAS with a crystallization solution, and then slowly cooling the PAS particles.

U.S. Pat. No. 4,056,515 U.S. Pat. No. 40600520 U.S. Pat. No. 4,066,632 Japanese Unexamined Patent Publication No. 59-001536 Japanese Unexamined Patent Publication No. 2004-051732 JP-A-2010-106179 Special Table 2016-536443

In the conventional continuous polymerization apparatus as shown in Patent Documents 1 to 3, for example, a plurality of pressure-resistant polymerization cans, piping between these polymerization cans, transfer equipment, instrumentation, etc. are required, and the reaction apparatus is required. Due to its complexity, manufacturing costs tend to increase. In addition, since a large amount of energy is required to drive the above-mentioned device, it is difficult to save resources, save energy, reduce equipment costs, and the like. In addition, the recovered polymer is in the form of fine powder, has a large proportion of low molecular weight oligomers, and has a large amount of terminal groups having low thermal stability. Such a fine powder-shaped polymer has a large amount of volatile matter during processing, low thermal stability, and a high halogen content. Therefore, it is difficult to obtain sufficient handleability during the post-treatment process and processing.

Further, there is a demand for a simpler and more efficient method for producing polymer particles, as opposed to a method for recovering a granular polymer from a reaction mixture as shown in Patent Documents 4 to 7.

The present invention has been made in view of the above problems, and provides a method for producing PAS, which enables resource saving, energy saving, and equipment cost reduction, and can easily and efficiently produce granular PAS. The purpose is.

According to the first aspect of the present invention, in the method for producing PAS according to the present invention, an organic polar solvent, a sulfur source and a sulfur source are used as reaction raw materials in a continuous polymerization apparatus having a plurality of reaction tanks communicating with each other via a gas phase. A supply step of supplying the dihalo aromatic compound, a polymerization reaction step of carrying out a polymerization reaction between the sulfur source and the dihalo aromatic compound in the organic polar solvent in at least one reaction vessel, and the reaction vessel. A removal step of removing at least a part of water in the gas phase portion from the reaction tank and a moving step of sequentially moving the reaction mixture in which the polymerization reaction is proceeding to each reaction tank are performed in parallel. It also includes a granulation step of adding a phase separator to granulate PAS and a recovery step of recovering the granulated polyarylene sulfide.

According to the above configuration, the plurality of reaction tanks communicate with each other via the gas phase portion, and the pressure in the gas phase is uniform. Then, the reaction mixture obtained by the progress of the polymerization reaction in each reaction vessel moves in each reaction vessel in sequence. On the other hand, water is equally removed from the gas phase of each reaction vessel. As a result, the amount of water in the reaction mixture decreases from the upstream side to the downstream side in the moving direction of the reaction mixture, and the reaction inhibition by water is suppressed, so that the polymerization reaction is easily promoted. Further, by adding a phase separation agent to the reaction mixture, granulating it, and then recovering it, a granular PAS having good handleability and excellent stability can be obtained.

According to the second aspect of the present invention, in the first aspect, the separation step of separating the solid contained in the reaction mixture can be performed before the granulation step.

By having the above structure, PAS having a low content of low molecular weight oligomer can be produced.

According to the third aspect of the present invention, in the first or second aspect, the separation cleaning step of separating the solid contained in the reaction mixture by sedimentation and performing countercurrent cleaning is performed before the granulation step. Can be done.

By having the above structure, a PAS granulated product having a low by-product salt content can be produced.

According to the fourth aspect of the present invention, in any one of the first to third aspects, the recovery step recovers the granulated polyarylene sulfide as a non-passing material of a sieve having a mesh size of 38 μm. It is preferable to do so.

By having the above structure, liquid and fine powder oligomers having a high chlorine terminal group content can be removed, so that oligomers having a low volatile component and PAS having a low halogen content can be obtained.

According to the fifth aspect of the present invention, in any one of the first to fourth aspects, the phase separating agent is placed in any of the plurality of reaction tanks before the end of the step of carrying out the polymerization reaction. It is preferable to add it.

According to the above configuration, while the polymerization reaction is continuously advanced, PAS granulation can be performed in parallel at the same time.

According to the sixth aspect of the present invention, in any one of the first to fourth aspects, the phase separation agent may be added to the reaction mixture after removing the reaction mixture from the continuous polymerization apparatus. preferable.

According to the above configuration, even when water is added as a phase separation agent, PAS can be rapidly polymerized without inhibiting the polymerization reaction.

According to the seventh aspect of the present invention, in the sixth aspect, it is preferable to slowly cool the reaction mixture after adding the phase separation agent.

According to the above configuration, granular PAS can be efficiently produced.

According to the eighth aspect of the present invention, in any one of the first to seventh aspects, after the phase separation agent is added, the reaction mixture is placed under polymerization conditions to further carry out the polymerization reaction. preferable.

According to the above configuration, high molecular weight granular PAS can be efficiently produced.

According to the ninth aspect of the present invention, in any one of the first to eighth aspects, the phase separating agent is preferably water, lithium chloride, sodium carboxylate, or a mixture thereof.

According to the above configuration, granular PAS can be efficiently produced.

In the tenth aspect of the present invention, in any one of the first to ninth aspects, at least one of the granulation step and the recovery step is carried out by the supply step, the polymerization reaction step, the removal step and the transfer. It is preferable to carry out in parallel with the process.

According to the present invention, it is possible to provide a method for producing PAS, which enables resource saving, energy saving, and equipment cost reduction, and can easily and efficiently produce granular PAS.

It is a partial cross-sectional view which shows one Embodiment including the continuous polymerization apparatus which concerns on this invention. It is a partial cross-sectional view which shows another embodiment including the continuous polymerization apparatus which concerns on this invention. It is a partial cross-sectional view which shows another embodiment including the continuous polymerization apparatus which concerns on this invention. It is a partial cross-sectional view which shows another embodiment including the continuous polymerization apparatus which concerns on this invention.

Hereinafter, embodiments of the present invention will be specifically described, but the present invention is not limited to these embodiments.

[Embodiment 1]
FIG. 1 is a partial cross-sectional view showing an embodiment (hereinafter, referred to as “Embodiment 1”) including the continuous polymerization apparatus according to the present invention. Hereinafter, the configuration of the first embodiment will be described with reference to FIG.

<Polyarence fluid continuous polymerization equipment>
First, the configuration of the PAS continuous polymerization apparatus that can be used in the method for producing polyarylene sulfide (PAS) according to the embodiment of the present invention (hereinafter, also referred to as “the production method”) will be described with reference to FIG. The PAS continuous polymerization apparatus 100 is composed of at least reference numerals 1 to 29. It preferably contains reference numerals 30 to 33, and more preferably reference numerals 34 to 36.

FIG. 1 is a partial cross-sectional view showing a configuration including a PAS continuous polymerization apparatus that can be used in the PAS production method according to the present embodiment.

Explaining with reference to FIG. 1, the PAS continuous polymerization apparatus 100 includes a storage chamber 2 for accommodating a plurality of reaction tanks 1a, 1b, and 1c.

The shape of the storage chamber 2 is a hollow cylindrical shape having a side wall 3a in contact with the reaction tank 1a and a side wall 3b in contact with the reaction tank 1c as the bottom surface. The shape of the storage chamber 2 is not limited to this, and a hollow prismatic shape may be laid down.

A line for supplying each reaction raw material is connected to the side wall 3a of the storage chamber 2. Specifically, the organic polar solvent supply line 4 for supplying the organic polar solvent to the storage chamber 2 and the storage chamber 2 are supplied with at least one sulfur source selected from the group consisting of alkali metal sulfide and alkali metal hydrosulfide. The sulfur source supply line 5 and the dihalo aromatic compound supply line 6 for supplying the dihalo aromatic compound to the storage chamber 2 are connected to the side wall 3a of the storage chamber 2, respectively. If necessary, a water supply line (not shown) for supplying water to the accommodating chamber 2 may be connected to the side wall 3a.

A reaction mixture recovery line 7 for recovering the reaction mixture from the storage chamber 2 is connected to the side wall 3b of the storage chamber 2. The organic polar solvent, the sulfur source, and the dihaloaromatic compound, which are the reaction raw materials, may be supplied to the liquid phase of the reaction tank 1a via the gas phase, or are directly supplied to the liquid phase of the reaction tank 1a. You may. In the present specification, the reaction raw material means a raw material used in the polymerization reaction of the PAS production method.

The reaction tank 1a and the reaction tank 1b are separated by a partition wall 8a, and the reaction tank 1b and the reaction tank 1c are separated by a partition wall 8b. The reaction tank 1a, the reaction tank 1b, and the reaction tank 1c communicate with each other via the gas phase in the storage chamber 2. As a result, the gas phase pressure in the containment chamber 2 becomes uniform. The effect of such communication will be described later.

The reaction tank 1a, the reaction tank 1b, and the reaction tank 1c are connected in series in the above order. In each reaction tank except the most upstream reaction tank 1a in the movement direction of the reaction mixture, the minimum height of the partition wall on the upstream side in the movement direction is higher than the maximum liquid level in the reaction tank. That is, in the reaction tank 1b, the minimum height of the partition wall 8a on the upstream side in the moving direction is higher than the maximum liquid level of the reaction tank 1b, and in the reaction tank 1c, the minimum height of the partition wall 8b on the upstream side in the moving direction. The height is higher than the maximum liquid level of the reaction vessel 1c. This prevents backflow from the reaction tank 1b to the reaction tank 1a and backflow from the reaction tank 1c to the reaction tank 1b. The reaction tank 1a, the reaction tank 1b, and the reaction tank 1c may contain the reaction mixture 9a, the reaction mixture 9b, and the reaction mixture 9c, respectively.

As described above, in a preferred embodiment of the continuous polymerization apparatus preferably used in the present invention, at least one set of reaction tanks is the maximum liquid that can be accommodated in the reaction tanks in the combination of adjacent reaction tanks. Connected in descending order of surface level, the reaction mixture may be configured to move from a reaction vessel with a higher maximum liquid level to a reaction vessel with a lower maximum liquid level due to the height difference of the maximum liquid level.

According to this configuration, since the reaction mixture moves according to the difference in the liquid level and the gravity, it is not necessary to provide a separate means for moving the reaction mixture to the next reaction tank.

In the storage chamber 2, the stirring blade 10a for stirring the reaction mixture 9a in the reaction tank 1a, the stirring blade 10b for stirring the reaction mixture 9b in the reaction tank 1b, and the stirring blade 10b for stirring the reaction mixture 9c in the reaction tank 1c. 10c is installed on the same stirring shaft 11. The stirring shaft 11 is installed so as to penetrate the side wall 3a from the outside of the accommodation chamber 2 and reach the side wall 3b. At the end of the stirring shaft 11 on the side wall 3a side, a rotation driving device 12 for rotating the stirring shaft 11 is installed.

One end of the exhaust line 13 is connected to the vicinity of the side wall 3a of the accommodation chamber 2. At the other end of the exhaust line 13, a dehydration section 14 for dehydrating from the gas phase in the accommodation chamber 2 is connected. The dehydration section 14 communicates with the gas phase in the accommodation chamber 2 through the exhaust line 13. One end of the organic polar solvent recovery line 15 is connected to one end (for example, the lower part) of the dehydration section 14. One end of the steam recovery line 16 is connected to the other end (for example, the upper part) of the dehydration unit 14. A gas-liquid separation unit 17 is connected to the other end of the steam recovery line 16. The reaction raw material separation / recovery unit 19 is connected to the other end of the gas recovery line 18 branched from one end (for example, the upper part) of the gas-liquid separation unit 17. The waste gas line 20 and the reaction raw material resupply line 21 are branched from the reaction raw material separation and recovery unit 19, and at least a part of the reaction raw material separated and recovered by the reaction raw material separation and recovery unit 19 is connected to the reaction raw material resupply line 21. The reaction raw material resupply unit 22 for resupplying the above to at least a part of the reaction tanks 1a to 1c is connected. On the other hand, the reaction raw material separation / recovery unit 24 is connected to the other end of the liquid recovery line 23 branched from the other end (for example, the lower part) of the gas-liquid separation unit 17. The wastewater line 25 and the reaction raw material resupply line 26 are branched from the reaction raw material separation and recovery unit 24, and at least a part of the reaction raw material separated and recovered by the reaction raw material separation and recovery unit 24 is connected to the reaction raw material resupply line 26. The reaction raw material resupply unit 27 for resupply is connected to at least a part of the reaction tanks 1a to 1c. At least a part of the reaction raw material may be supplied to at least a part of the liquid phases of the reaction tanks 1a to 1c via the gas phase, or directly to at least a part of the liquid phases of the reaction tanks 1a to 1c. May be done.

The side wall 3b of the containment chamber 2 communicates with the gas phase in the containment chamber 2, and the gas phase is directed from the downstream side to the upstream side in the moving direction of the reaction mixture, that is, from the reaction tank 1c toward the reaction tank 1a. The air supply unit 28 that feeds the inert gas to the air supply unit 28 is connected via the air supply line 29. The inert gas is not particularly limited, and examples thereof include a rare gas such as argon; nitrogen and the like.

A granulation portion 30 for granulation is connected to the other end of the reaction mixture recovery line 7 connected to the side wall 3b of the storage chamber 2. A phase separating agent supply line 31 is connected to one end of the granulation portion 30. A solid recovery line 32 and a liquid recovery line 33 are connected to the other end of the granulation section 30. A sieve 34 is connected to the other end of the solid recovery line 32, and a sieve passing material recovery line 35 for collecting solids that have passed through the mesh of the sieve 34 and a sieve non-passing material recovery line 36 that does not pass through the mesh are connected. ing. The granulation unit 30 preferably includes a stirring blade for stirring the reaction mixture and the phase separation agent, a cooling means for cooling the separation phase, and a separation means for separating the solid and the liquid composed of the formed granular PAS. I have. The cooling means is not particularly limited, and for example, a side wall jacket, heat exchange in a heat transfer tube, for example, a reflux condenser or the like can be used alone or in combination.

In another embodiment, the mixing portion of the reaction mixture and the phase separation agent may be connected to a reaction vessel located further upstream, for example, the reaction vessel 1b or 1c. That is, a reaction mixture recovery line is separately provided on the side wall of the reaction tank 1b or 1c, and the recovered reaction mixture is sent to the mixing section, where the phase separation agent is added and mixed, and then the reaction tank 1b or any other option is used again. It can also be returned to the reaction tank of. The reaction mixture containing the phase separation agent may be subjected to a further polymerization reaction, then recovered from the reaction mixture recovery line 7, granulated by slow cooling, and subjected to a sieving means.

In yet another embodiment, the phase separation agent may be added directly to the reaction mixture in the reaction tank, instead of removing the reaction mixture from the reaction vessel and then mixing it with the phase separation agent. In this case, it is preferable to use a water-free phase separating agent. Similarly to the above, the reaction mixture containing the phase separation agent is subjected to a further polymerization reaction as necessary, then recovered from the reaction mixture recovery line 7, granulated by slow cooling, and subjected to a sieving means. ..

Next, based on FIG. 1, the PAS manufacturing method according to the present embodiment will be described together with the description of the operation of the PAS manufacturing apparatus.

<PAS manufacturing method>
The present production method comprises a supply step of supplying an organic polar solvent, a sulfur source and a dihalo aromatic compound as reaction raw materials to at least one of a plurality of reaction tanks communicating with each other via a gas phase, and at least one of the reaction tanks. , A polymerization reaction step of carrying out a polymerization reaction of the sulfur source and the dihalo aromatic compound in the organic polar solvent, and removal of removing at least a part of water in the gas phase portion of the reaction tank from the reaction tank. The step and the moving step of sequentially moving the reaction mixture in which the polymerization reaction is proceeding to each reaction vessel are carried out in parallel, and further, a phase separating agent is added to granulate the polyarylene sulfide. It includes a granulation step and a recovery step of recovering the granulated polyarylene sulfide.

Specifically explaining this production method, in the supply process, in the storage chamber 2, at least one sulfur source selected from the group consisting of an organic polar solvent, an alkali metal sulfide and an alkali metal hydrosulfide, and a dihaloaromatic are provided. Each reaction material of the compound is supplied through an organic protictic solvent supply line 4, a sulfur source supply line 5, and a dihaloaromatic compound supply line 6, respectively. A part or all of the reaction raw materials may be mixed in advance and then supplied to the storage chamber 2. For example, a mixture of an organic polar solvent and a dihaloaromatic compound may be prepared in advance, and this mixture may be supplied to the storage chamber 2. In this case, for example, instead of the organic polar solvent supply line 4 and the dihaloaromatic compound supply line 6, a mixture supply line (not shown) is connected to the side wall 3a, and the mixture is introduced into the storage chamber 2 through the mixture supply line. Can be supplied.

The supplied organic polar solvent, sulfur source, and dihalo aromatic compound are first mixed in the reaction vessel 1a in the polymerization step, and the polymerization reaction between the sulfur source and the dihalo aromatic compound in the organic polar solvent. As a result, the reaction mixture 9a is formed. In some cases, the polymerization reaction may not substantially proceed in the reaction tank 1a, only dehydration may be performed, and the polymerization reaction may proceed in the reaction tank 1b and thereafter.

As the at least one sulfur source selected from the group consisting of organic polar solvents, alkali metal sulfides and alkali metal hydrosulfides, and dihaloaromatic compounds, those usually used in the production of PAS can be used.

Examples of the organic polar solvent include an organic amide solvent. Examples of the organic amide solvent include amide compounds such as N, N-dimethylformamide and N, N-dimethylacetamide; N-alkylcaprolactam compounds such as N-methyl-ε-caprolactam; N-methyl-2-pyrrolidone (NMP). ), N-alkylpyrrolidone compounds such as N-cyclohexyl-2-pyrrolidone or N-cycloalkylpyrrolidone compounds; N, N-dialkylimidazolidinone compounds such as 1,3-dialkyl-2-imidazolidinone; tetramethylurea Tetraalkylurea compounds such as, hexaalkylphosphoric acid triamide compounds such as hexamethylphosphoric acid triamide, and the like.

Examples of the sulfur source include alkali metal sulfide, alkali metal hydrosulfide, hydrogen sulfide and the like. The sulfur source is preferably an alkali metal sulfide or an alkali metal hydrosulfide from the viewpoint of easy handling and low cost. The sulfur source can be handled, for example, in the state of an aqueous slurry or an aqueous solution, and is preferably in the state of an aqueous solution from the viewpoint of handleability such as measurable property and transportability.

Examples of the alkali metal sulfide include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and the like.

Examples of the alkali metal hydrosulfide include lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide and the like.

Examples of the dihaloaromatic compound include o-dihalobenzene, m-dihalobenzene, p-dihalobenzene, dihalotoluene, dihalonaphthalene, methoxy-dihalobenzene, dihalobiphenyl, dihalobenzoic acid, dihalodiphenyl ether, dihalodiphenylsulfone and dihalo. Examples thereof include diphenyl sulfoxide and dihalodiphenyl ketone. Halogen atoms in dihaloaromatic compounds refer to the atoms of fluorine, chlorine, bromine, and iodine. The two halogen atoms in the dihalo aromatic compound may be the same or different.

Each of the alkali metal sulfide, the alkali metal hydrosulfide, and the dihalo aromatic compound may be used alone, or if it is a combination capable of producing PAS, two or more kinds may be mixed and used. You may.

Water may be added to at least one of the reaction tanks 1a to 1c. The amount of water added at that time can be, for example, about 0.1 to 10 mol per 1 mol of the sulfur source.

The polymerization reaction is preferably carried out at 170 ° C. to 290 ° C. until the conversion rate of the dihalo aromatic compound becomes 50% or more.

The conversion rate of the dihalo aromatic compound is preferably 50 to 100%, more preferably 60 to 100%, still more preferably 65 to 100%, and particularly preferably 70 to 100%. The conversion rate of the dihalo aromatic compound is determined by determining the amount of the dihalo aromatic compound remaining in the reaction mixture by gas chromatography or liquid chromatography, and determining the residual amount, the amount of the dihalo aromatic compound charged, and the amount of the sulfur source charged. It can be calculated based on.

In the present production method, in the dehydration step, at least a part of the water in the storage chamber 2 is transmitted through the gas phase in the storage chamber 2 due to the action of the dehydration unit 14 through the exhaust line 13 (details will be described later). Removed from containment chamber 2. As a result, at least a part of the water present in the reaction tanks 1a to 1c is removed. Examples of the water in the storage chamber 2 include water supplied to the storage chamber 2, water generated by the polymerization reaction, and the like. Here, the water supplied to the storage chamber 2 is, for example, the water positively supplied to the storage chamber 2 and, when the water is not positively supplied to the storage chamber 2, is usually used as a reaction raw material. Refers to the water supplied to the storage chamber 2 together with the reaction raw material in a contained state. Since water has a high vapor pressure, if the gas phase of the containment chamber 2 contains a large amount of water, the inside of the containment chamber 2 tends to have a high pressure, and the pressure resistance of the containment chamber 2 needs to be increased, which saves resources and reduces equipment costs. Etc. are difficult to plan. By dehydrating by the dehydrating unit 14 and reducing the pressure inside the storage chamber 2, resource saving, equipment cost reduction, and the like can be effectively realized.

The pressure in the accommodating chamber 2 which is a reaction system can be lowered to a gauge pressure of 0 MPa as a range in which the supplied solvent is lowered to a pressure at which it does not boil. Although it depends on the temperature of each reaction vessel, it can be lowered to 0.0001 MPaG (G indicates a gauge pressure), preferably about 0.01 to 0.03 MPaG. Further, it is possible to make the gauge pressure negative, but it is not preferable from the viewpoint of the energy cost for generating the negative pressure and the decrease in the boiling point of the solvent.

For example, it is preferably 0.0001 MPaG or more and 0.8 MPaG or less, more preferably 0.01 MPaG or more and 0.65 MPaG or less, further preferably 0.02 MPaG or more and 0.39 MPaG or less, and 0. It is particularly preferable that it is 0.03 MPaG or more and 0.37 MPaG or less.

As described above, the reaction tanks 1a to 1c communicate with each other via the gas phase in the storage chamber 2, and the pressure of the gas phase in the storage chamber 2 is uniform. Therefore, in the dehydration step, water is removed from all of the reaction tanks 1a to 1c by the dehydration section 14. Therefore, the amount of water in the reaction mixture decreases from the reaction tank 1a toward the reaction tank 1c, that is, from the upstream side to the downstream side in the moving direction of the reaction mixture. As a result, the reaction inhibition by water is suppressed and the polymerization reaction is promoted. Further, since the boiling point of the reaction mixture rises, polymerization at a high temperature becomes possible, and the polymerization reaction can be further promoted. Then, by promoting the polymerization reaction described above, the temperature of the reaction mixture is likely to rise, and the polymerization reaction is more likely to be promoted.

As described above, in the PAS continuous polymerization apparatus 100, for example, the temperatures of the reaction tanks 1a to 1c increase from the upstream side to the downstream side in the moving direction throughout the continuous reaction by arranging each part as described above. Can be raised. In other words, the internal temperature of the reaction tanks 1a to 1c can be set so as to increase from the upstream side to the downstream side in the moving direction of the reaction mixture.

Further, as described above, the reaction tanks 1a to 1c are connected in descending order of the maximum liquid level of the liquid that can be accommodated in each reaction tank. Thereby, in the step of moving the reaction mixture, the reaction mixture can be sequentially moved by utilizing the height difference of the maximum liquid level. More specifically, when the reaction mixture 9a and the reaction mixture 9b exceed the maximum liquid level of each reaction vessel, the partition walls 8a and the partition wall 8b can be exceeded, respectively. The shapes of the partition walls 8a and 8b are not particularly limited as long as the reaction tanks 1a, the reaction tank 1b, and the reaction tank 1c are not prevented from communicating with each other via the gas phase in the storage chamber 2, and any shape is not particularly limited. It may be. Further, the reaction solution may be moved by an opening of the partition wall, for example, a through hole or a slit (neither of which is shown).

In this embodiment, the internal temperatures of the reaction tanks 1a, 1b, and 1c are all 150 ° C. or higher. Preferably, the supply reaction vessel to which the reaction raw material is supplied, that is, the reaction vessel 1a is 160 ° C. or higher, more preferably 170 ° C. or higher, and further preferably 180 ° C. or higher. The internal temperature of each of the reaction tanks other than the supply reaction tank, that is, the reaction tanks 1b and 1c, is preferably 200 ° C. or higher, more preferably 210 ° C. or higher, and further preferably 220 ° C. or higher. Further, among the reaction tanks other than the supply reaction tank, the internal temperature of at least one reaction tank is preferably 245 ° C. or higher, more preferably 250 ° C. or higher, still more preferably 255 ° C. or higher. In the present embodiment, the difference in internal temperature between the reaction tanks adjacent to each other is preferably 2 ° C. or higher, more preferably 3 ° C. or higher, and even more preferably 5 ° C. or higher. By setting the internal temperatures of the reaction tanks 1a to 1c in this way, the above-mentioned dehydration step is mainly performed in the supply reaction tank, that is, the reaction tank 1a, and the reaction mixture is moved downstream to the reaction tank 1a. The polymerization reaction can be mainly carried out in the provided reaction tank, that is, the reaction tank 1b, and as a result, the polymerization reaction can be carried out more efficiently.

In the present embodiment, the air supply unit 28 applies an inert gas to the gas phase in the storage chamber 2 from the downstream side to the upstream side in the moving direction of the reaction mixture, that is, from the reaction tank 1c to the reaction tank 1a. It is preferable to send it. As described above, in order to maintain a state in which the amount of water in the reaction mixture decreases from the upstream side to the downstream side in the moving direction of the reaction mixture, the water evaporated from the reaction mixture flows to the downstream side. , It is preferable not to condense on the reaction mixture. By feeding the inert gas into the gas phase as described above by the air supply unit 28, it is possible to effectively prevent water vapor from flowing to the downstream side and condensing on the reaction mixture.

The flow velocity of the inert gas is not particularly limited as long as the water vapor does not easily flow to the downstream side.

The stirring shaft 11 is rotated by the rotation driving device 12, and the stirring blades 10a to 10c installed on the stirring shaft 11 rotate around the stirring shaft 11, and the reaction mixtures 9a to 9c are stirred. The stirring blades 10a to 10c are installed on the same stirring shaft 11. Therefore, by simply rotating the stirring shaft 11 with the rotation driving device 12, all of the stirring blades 10a to 10c can be rotated under the same conditions, and uniform stirring can be realized with high efficiency.

As the polymerization reaction proceeds, alkali metal halides such as NaCl are precipitated and accumulated in the reaction tanks 1a to 1c. As a result, for example, the volume effective for advancing a sufficient polymerization reaction in the reaction tanks 1a to 1c decreases, and productivity tends to decrease. In addition, extra maintenance work is required to remove the accumulated alkali metal halide. By stirring the reaction mixture 9a to 9c with the stirring blades 10a to 10c, the alkali metal halide is dispersed in the reaction mixture 9a to 9c, moves to the downstream side, and is easily discharged to the outside of the storage chamber 2. It becomes. On the other hand, if the stirring is too vigorous, the reaction mixture tends to be unnecessarily mixed into the reaction tank on the upstream side to the reaction tank on the downstream side beyond the partition wall 8a and / or the partition wall 8b.

It is preferable to appropriately adjust the shape, number of blades, rotation speed, etc. of the stirring blades so as to promote the dispersion of the alkali metal halide and avoid unnecessary mixing of the reaction mixture between the reaction tanks 1a to 1c. Among these, examples of the rotation speed of the stirring blade include conditions under which the alkali metal halide does not settle, and more specifically, a rotation speed at which the stirring speed by the stirring blade becomes equal to or higher than the particle floating limit stirring speed. The upper limit of the rotation speed at the tip of the stirring blade is preferably a speed at which the rotation speed of the stirring blade is 120 mp or less, preferably 60 mp or less, in that it is easy to prevent the reaction mixture from exceeding the partition 8a and / or the partition 8b. A speed such that becomes more preferable. Further, it is preferable to appropriately adjust the rotation path and the like of the stirring blade so that the stirring is sufficiently performed.

Exhaust gas from the accommodating chamber 2 is supplied to the dehydrating section 14 through the exhaust line 13. The dehydration section 14 acts as, for example, a distillation column, and a liquid containing an organic polar solvent as a main component is recovered from one end (for example, the lower part), and the sulfur source and water are collected from the other end (for example, the upper part). The vapor containing the above, and optionally the dihalo aromatic compound, is recovered.

The organic polar solvent recovered from the dehydration section 14 may be appropriately purified and then supplied to the storage chamber 2 again as a reaction raw material for the polymerization reaction. At that time, the recovered organic polar solvent may be supplied to the storage chamber 2 through the organic polar solvent supply line 4 or through an organic polar solvent supply line other than the organic polar solvent supply line 4. The recovered organic polar solvent may be supplied to any one of the reaction tanks 1a to 1c, or a combination of two or more of these.

The steam recovered from the other end of the dehydration section 14 is supplied to the gas-liquid separation section 17 via the steam recovery line 16. The gas-liquid separation unit 17 acts as, for example, a distillation column, and the gas containing the sulfur source is recovered from one end (for example, the upper part), and the dihalo aromatic compound and the dihalo aromatic compound and the dihalo aromatic compound and the like from the other end (for example, the lower part). / Or a liquid containing water is recovered.

The gas recovered from the one end of the gas-liquid separation section 17 is supplied to the reaction raw material separation and recovery section 19 via the gas recovery line 18. In the reaction raw material separation / recovery unit 19, the sulfur source is separated and recovered from the gas by absorbing the gas into a polar organic solvent, an alkaline solution, or a mixture thereof, and the reaction raw material is separated and recovered from the gas via the reaction raw material resupply line 21. It is sent to the resupply unit 22. On the other hand, the remaining gas is discarded as waste gas through the waste gas line 20.

It is preferable that at least a part of the sulfur source separated and recovered by the reaction raw material separation and recovery unit 19 is resupplied to at least one of the reaction tanks 1a to 1c by the reaction raw material resupply unit 22. At that time, the separated and recovered sulfur source may be resupplied to the reaction vessel 1a through the sulfur source supply line 5 or through a sulfur source supply line other than the sulfur source supply line 5. By resupplying at least a part of the sulfur source, the sulfur source can be effectively used and resources can be saved.

The liquid recovered from the gas-liquid separation unit 17 is supplied to the reaction raw material separation / recovery unit 24 via the liquid recovery line 23. In the reaction raw material separation and recovery unit 24, the dihalo aromatic compound is separated and recovered from the liquid and sent to the reaction raw material resupply unit 27 via the reaction raw material resupply line 26. On the other hand, the remaining liquid is discarded as wastewater through the wastewater line 25.

For this reason, it is preferable that at least a part of the dihalo aromatic compound separated and recovered by the reaction raw material separation and recovery unit 24 is resupplied to at least one of the reaction tanks 1a to 1c by the reaction raw material resupply unit 27. At that time, the separated and recovered dihalo aromatic compound may be resupplied to the reaction vessel 1a through the dihalo aromatic compound supply line 6 or through a dihalo aromatic compound supply line other than the dihalo aromatic compound supply line 6. You may go. By resupplying at least a part of the dihalo aromatic compound, the dihalo aromatic compound can be effectively utilized and resources can be saved.

Further, in driving the continuous polymerization apparatus 100, the reaction mixture is moved by using gravity based on the height difference of the maximum liquid level, and a large amount of energy is not required. Therefore, the continuous polymerization apparatus 100 can easily save resources, save energy, reduce equipment costs, and the like.

The lower limit of the weight average molecular weight (Mw) of PAS obtained by this production method by gel permeation chromatography (GPC) is 8,000 or more, preferably 10,000 or more, more preferably 13,000 or more, and particularly preferably. Is 15,000 or more, and it is possible to obtain a high molecular weight PAS of 20,000 or more. The upper limit is 200,000 or less, preferably 100,000 or less, and more preferably 70,000 or less.

The yield of PAS obtained by this production method per unit space / time is preferably 14 g / hr · L or more, more preferably 14.5 g / hr · L or more, and 15 g / hr. -L or more is more preferable, and 16 g / hr · L or more is particularly preferable.

As described above, according to the present production method, since the reaction raw material may be supplied to at least one of a plurality of reaction tanks communicating with each other via the gas phase, complicated control or the like is not required, and PAS can be produced. It will be easy.

In the granulation section 30, the reaction mixture supplied from the reaction mixture recovery line 7 and the phase separation agent supplied from the phase separation agent supply line 31 are dissolved or melted in the organic polar solvent under stirring. It is mixed in the state of being. The reaction mixture recovered from the reaction mixture recovery line 7 is appropriately separated and removed by filtration or the like before the phase separation agent is added at the granulation section 30. It may be subjected to processing.

Liquid-liquid phase separation occurs by adding a phase separation agent to the reaction mixture while the PAS remains dissolved or melted in an organic protic solvent. Then, under stirring, the temperature of the liquid-liquid separation phase is gradually lowered by a cooling means provided in the granulated portion, so that the PAS is solidified and a granular PAS is formed. The formed granular PAS (solid) and other liquids and microsolids such as by-products are separated by various separation means and recovered from the solid recovery line 32 and the liquid recovery line 33, respectively.

The slurry after the granular PAS is formed is mainly composed of the granular PAS, a polymerization solvent, a by-product salt and the like. Examples of the method for recovering the granular PAS from the slurry include a method of sieving the granulated granular PAS and recovering the granulated PAS, and a method of recovering the granulated granular PAS together with the fine particle PAS and the PAS oligomer. Be done.

For example, the sieve content recovery method is a method in which granulated and granular PAS is separated from other components by a sieve and, if necessary, washed with a washing liquid to obtain a clean granular PAS. By this method, the oligomer component which becomes a volatile component at the time of processing is removed, and PAS having a low chlorine content can be obtained.

Further, for example, there is a method in which the slurry after the granular PAS is formed is ejected from a nozzle at a high temperature state, and all or a part of the solvent is instantaneously evaporated to obtain a solid substance (including a muddy substance). Further, there is a method of removing the by-product salt from the solid substance with water or the like and, if necessary, further washing with a washing liquid to obtain a clean fine particle PAS or a granular PAS containing an oligomer component. By this method, although there are many oligomer components that become volatile during processing, the amount recovered can be increased.

The solid substance (including the muddy substance) may be sieved to collect only the granular PAS.

Alternatively, for example, a method of obtaining a granular PAS containing a clean oligomer component by solid-liquid separation of the slurry after the granular PAS is formed by a centrifuge or the like and then washing with water or an organic solvent can be mentioned. By this method, although there are many oligomer components that become volatile during processing, the amount recovered can be increased.

The polar organic solvent or the like recovered from the liquid recovery line 33 is appropriately purified as necessary and resupplied to the reaction vessel as a reaction raw material. On the other hand, the granular PAS recovered from the solid recovery line 32 is supplied to the sieve 34 as needed, sieved by a mesh having a desired opening, and becomes a granular PAS having a particle size of a desired size. , Separated from other fine powder and collected. Product PAS particles are obtained by separating by filtration, sieving, etc., washing with an organic solvent, high-temperature water, or the like, and drying.

As the phase separating agent, a known compound known to function as a phase separating agent can be used. Specific examples of the phase separator include water, organic carboxylic acid metal salts, organic sulfonic acid metal salts, alkali metal halides such as lithium halide, alkaline earth metal halides, alkaline earth metal salts of aromatic carboxylic acids, and phosphorus. Examples thereof include acid-alkali metal salts, alcohols, and paraffinic hydrocarbons. Examples of the organic carboxylic acid metal salt include alkali metal carboxylic acids such as lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, lithium benzoate, sodium benzoate, sodium phenylacetate, and potassium p-toluic acid. Salt is preferred. These phase separators can be used alone or in combination of two or more. Among these phase separators, water, an organic carboxylic acid metal salt such as an alkali metal carboxylate, lithium chloride, and a combination thereof are preferable in terms of granulation effect (increase in particle size). Water that is easy to post-treat, sodium acetate, which is inexpensive, or a combination of water and sodium acetate is particularly preferred.

The amount of the phase separation agent added may be appropriately adjusted within the range in which phase separation, that is, liquid-liquid phase separation occurs, according to the PAS concentration in the reaction mixture, the type of phase separation agent to be added, the temperature, and the like. it can. The amount and temperature of the phase separating agent added can be determined by observing the minimum amount of liquid-liquid phase separation of PAS melted and dissolved in the polar organic solvent in a transparent heat-resistant glass ampoule.

For example, when water is used as the phase separating agent, the phase separating agent (water) is preferably 0.35 parts by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the organic amide solvent of the reaction mixture, particularly NMP. Is 0.41 molar mass or more and 1.8 molar mass or less, and more preferably 0.42 molar mass or more and 1.5 molar mass or less.

When water and a phase separating agent other than water are used in combination as the phase separating agent, 0.01 to 2 mol by mass, preferably 0.02 to 1 mol, based on 100 parts by mass of the organic amide solvent, particularly NMP. Adjusting to the range of parts by mass, more preferably 0.03 to 0.8 mol by mass, particularly preferably 0.05 to 0.5 mol by mass, and adding a phase separating agent other than water to the organic amide. It is preferably present in the range of 0.001 to 0.1 molar mass with respect to 100 parts by mass of the solvent. Another phase separator that is particularly preferably used in combination with water is an organic carboxylic acid metal salt, especially an alkali metal carboxylate, in which case water is added to an organic amide solvent, particularly 100 parts by weight of NMP. It is used in the range of 0.01 to 1.5 molar parts by mass, preferably 0.05 to 1.0 molar parts by mass, particularly preferably 0.08 to 0.8 molar parts by mass, and an alkali metal carboxylate. May be used in the range of 0.0001 to 0.07 mol, preferably 0.002 to 0.06 mol by mass, and particularly preferably 0.005 to 0.05 mol by mass.

After liquid-liquid phase separation is achieved, the temperature of the separated phase is slowly cooled to below the temperature at which PAS crystallizes. For example, it is slowly cooled at a rate of 0.1 to 3 ° C./min to 1 to 10 ° C. or lower, which is the temperature at which PAS crystallizes. The crystallizing temperature can be determined, for example, by observing the temperature at which the liquid-liquid phase separated PAS precipitates in a transparent heat-resistant glass ampoule. After slowly cooling to 1 to 10 ° C. or lower, which is the temperature at which PAS crystallizes, the temperature may be rapidly cooled to less than 200 ° C., preferably 150 ° C. or lower, and further to 100 ° C. to room temperature.

The granular PAS obtained by the production method of the present invention is a PAS that does not pass through a sieve having a mesh size of 38 μm. The average particle size is preferably 50 to 5,000 μm, more preferably 70 to 3,000 μm, and even more preferably 100 to 2,000 μm. When the average particle size is in this range, the handling property and low dust property of PAS are excellent, and when supplying PAS to the processing equipment, the problem of causing poor biting and the problem of causing dusting can be solved. ..

In the specification of the present application, the average particle size refers to 400 mesh, 200 mesh, 150 mesh, 100 mesh, 60 mesh, 32 mesh, 24 mesh, 16 mesh, 12 mesh, from the bottom, according to JIS K-0069. And 9 mesh sieves are stacked, granular PAS is placed on the top sieve, and using an electromagnetic sieve shaker (Anysette 3) manufactured by FRITSCH, permeation time = 15 minutes, AMPLITUDE = 5, It is a value calculated by performing the measurement with INTERVAL = 6.

When the granular PAS and the fine particle PAS and / or the PAS oligomer are mixed, the granular PAS is preferably 30% by mass or more, more preferably 50% by mass or more.

The present embodiment may further include a step of increasing the weight average molecular weight of PAS obtained by the polymerization step. The weight average molecular weight of PAS can be increased by using a polymerization aid, for example, in a polymerization reaction. Specific examples of such polymerization aids include organic carboxylates, organic sulfonates, alkali metal sulfates, alkaline earth metal oxides, alkali metal phosphates and alkaline earth metal phosphates. Can be mentioned. These can be used alone or in combination of two or more. Of these, organic carboxylates are preferably used. More specifically, lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium benzoate, sodium benzoate, sodium phenylacetate, sodium p-toluic acid and the like can be mentioned. As the organic carboxylate, one kind or two or more kinds can be used at the same time. Of these, lithium acetate and / or sodium acetate are preferably used, and sodium acetate is more preferably used because it is inexpensive and easily available.

These polymerization aids may be used alone or in combination of two or more as long as PAS can be produced.

In the present embodiment, assuming that the total amount of water contained in each reaction raw material is 100% by mass, the amount of water contained in the above-mentioned supply reaction tank, that is, the reaction tank 1a is 5% by mass or more and 99% by mass or less. It is preferably 6% by mass or more and 90% by mass or less, and further preferably 7% by mass or more and 80% by mass or less. It is preferable that the amount of water contained in the feed reaction tank is within this range from the viewpoint of reducing the amount of water dehydrated in the polymerization step.

Further, the amount of water contained in the adjacent reaction tank adjacent to the downstream side of the supply reaction tank, that is, the reaction tank 1b is preferably 5% by mass or more and 50% by mass or less, and 6% by mass or more and 40% by mass. It is more preferably 7% by mass or more and 30% by mass or less. It is preferable that the amount of water contained in the adjacent reaction vessel is in this range from the viewpoint of reducing the amount of water dehydrated in the polymerization step.

In the present embodiment, a reaction vessel having a specific shape is used, but the shape of the reaction vessel is not particularly limited.

Further, the number of reaction tanks in the present embodiment is not particularly limited. Further, the reaction tanks do not necessarily have to be connected in series as shown in FIG. Therefore, for example, some of the plurality of reaction tanks may be arranged in parallel.

Further, in at least one pair of adjacent reaction tanks among the plurality of reaction tanks, the reaction tank having the higher maximum liquid level level of the liquid that can be accommodated in each reaction tank is located on the upstream side in the direction in which the reaction mixture moves. Therefore, it is preferable to move the reaction mixture by utilizing the height difference of the maximum liquid level. As a result, since the reaction mixture can be moved by using gravity in at least one pair of reaction tanks, resource saving, energy saving, equipment cost reduction, and the like can be achieved.

Further, in the present embodiment, the feeding step of feeding the inert gas described above is preferably performed in parallel with the feeding step, the dehydration step and the polymerization step described above. Furthermore, as described above, the separation and recovery step of separating and recovering a part of the reaction raw material and the resupply step of supplying at least a part of the reaction raw material to at least one of the reaction tanks are the above-mentioned supply step and dehydration. It is preferable to carry out in parallel with the step and the polymerization step.

Further, in the present embodiment, the configuration for supplying the reaction raw material to the reaction tank 1a has been described, but the reaction tank to which the reaction raw material is supplied is not specified.

[Embodiment 2]
Further, a modified example of the continuous polymerization apparatus shown in the above-described first embodiment will be described with reference to FIG.

Explaining with reference to FIG. 2, in the continuous polymerization apparatus 200, in the reaction vessel 44 corresponding to the storage chamber 2 of the first embodiment, the isolation means for separating the reaction vessel is not a partition wall but a partition plate having a rotation center. This is different from the first embodiment.

In the present embodiment, the reaction tank 1a and the reaction tank 1b are separated by a partition plate 45a, and the reaction tank 1b and the reaction tank 1c are separated by a partition plate 45b. The reaction vessel 1a, the reaction vessel 1b, and the reaction vessel 1c communicate with each other via the gas phase portion in the reaction vessel 44.

Further, a stirring blade 10a for stirring the reaction mixture 9a in the reaction tank 1a is attached to one side of the partition plate 45a. Similarly, a stirring blade 10b for stirring the reaction mixture 9b in the reaction tank 1b is attached to one side of the partition plate 45b. The stirring blades 10a and 10b in the present embodiment have a structure in which an opening is provided inside, unlike the stirring blades 10a and 10b in the above-described embodiment.

The stirring blades 10a and 10b and the partition plates 45a and 45b are all installed on the same rotating shaft 43. The rotating shaft 43 is installed so as to penetrate the side wall 3a from the outside of the reaction vessel 44 and reach the side wall 3b. At the end of the rotary shaft 43 on the side wall 3a side, a rotary drive device 12 for rotating the rotary shaft 43 is installed.

The stirring blade can be installed at an arbitrary position with respect to the partition plate. The partition plate may be on the upstream side of the stirring blade, on the downstream side, or may be a mixture of these. The partition plate may be separated from the stirring blade, but it is preferable to connect the partition plate in close contact with the stirring blade because the partition plate can be fixed and reinforced. Further, the stirring blade and the partition plate do not necessarily have to be a pair, and there may be a place where there is no stirring blade between the adjacent partition plates. By providing at least one stirring blade, it is possible to assist the progress of the polymerization reaction and to make the movement of the solid in the reaction mixture smoother. Alternatively, it is not necessary to provide a stirring blade, which enables a simpler device configuration.

The shape of the partition plate is not particularly limited, and has a rotation center and a clearance having a predetermined width so that the vertical cross section in the reaction vessel 44 is partially closed while the adjacent reaction tanks communicate with each other. Alternatively, it may have any shape that provides an opening. For example, when the reaction vessel 44 has a hollow cylindrical shape, as shown in FIG. 2, it may be a disk-shaped partition plate having a radius one size smaller than the internal space of the reaction vessel. The shape of the partition plate is not limited to this, and may be a cage-shaped rotating object having no central axis.

The number of partition plates provided on the rotating shaft may be any number of 1 or more depending on the size of the reaction vessel, the type of polymerization reaction, and the like.

When two or more partition plates are provided, they may have the same shape or may be different from each other.

Further, the position of each partition plate is not particularly limited and can be provided at any position.

On the other hand, the shape of the stirring blade is not particularly limited, and may be any shape provided coaxially with the partition plate and agitating the reaction mixture. As shown in FIG. 2, the stirring blade 10 may be attached to either one side of the partition plate, or may be attached to both sides. Alternatively, it may be mounted on the rotating shaft 43 separately from the partition plate.

The liquid phase portions of the reaction tanks 1a to 1c communicate with each other. As a result, the raw materials and the solvent supplied to the reaction tank 1a sequentially move to the reaction tanks 1b and 1c while advancing the polymerization reaction as a reaction mixture.

Further, the reaction tanks 1a to 1c communicate with each other in their gas phase portions. As a result, the pressure of the gas phase in the reaction vessel 44 becomes uniform. Then, the evaporation component generated at the time of polymerization in each reaction vessel sequentially moves from the reaction vessel 1c to the directions of 1b and 1a via the gas phase portion due to the temperature difference inside the apparatus and the like, and from the exhaust line 13. It is discharged.

In the continuous polymerization apparatus 200 of the present embodiment, there is a clearance having a predetermined width between the inner wall of the reaction vessel 44 and the outer edges of the partition plates 45a to 45b. As a result, the gas phase parts and the liquid phase parts of the adjacent reaction tanks communicate with each other, and the reaction mixture, the gas containing the evaporation component, and the like move. Instead of providing a clearance, an opening, for example, a through hole or a slit may be provided in the partition plate, and the reaction tank may be communicated through the opening. Alternatively, both clearances and openings may be provided. Alternatively, the partition plate may have a mesh shape having a plurality of fine through holes.

The width of the clearance or the size of the opening is not particularly limited, and can be appropriately set according to the shape of the container, the shape and number of partition plates, and the like.

In the second embodiment, points other than the above are as described in the first embodiment.

[Embodiment 3]
Further, a modified example of the continuous polymerization apparatus shown in the above-described first embodiment will be described with reference to FIG.

Explaining with reference to FIG. 3, the continuous polymerization apparatus 300 separates the solid contained in the reaction mixture by sedimentation at the bottom of the reaction tank 1c located at the most downstream in the moving direction of the reaction mixture, and also directs the reaction mixture. It differs from the first embodiment in that a cleaning unit 40 for performing flow cleaning is provided. The cleaning unit may be provided further downstream of the reaction tank located at the most downstream side.

In another embodiment, the wash section may be provided at the bottom of any reaction vessel located upstream. For example, a washing portion may be provided at the bottom of the reaction tank where by-product salt is likely to be generated. In yet another embodiment, the wash section can be provided at the bottom of a plurality of reaction vessels.

Further, in the continuous polymerization apparatus 300, a settling separation tank adjacent to the reaction tank 1c located at the most downstream in the moving direction of the reaction mixture may be further provided, and a washing part may be provided at the bottom of the settling separation layer.

In the present embodiment, the cleaning portion 40 has a tubular structure portion extending in the vertical direction and is vertically installed at the bottom of the reaction tank 1c. The tubular structure portion constituting the cleaning portion 40 is provided with a static mixing mechanism 41 in the cylinder. Further, the cleaning liquid is supplied to the cleaning unit 40 from the lower side to the upper side of the cleaning unit through the cleaning liquid supply line. Therefore, in the cylinder, there is a downward flow in which the solid settles and an upward flow due to the cleaning liquid supplied from the lower side to the upper side of the cleaning portion, and these are agitated by the static mixing mechanism 41. As the cleaning liquid, for example, a polymerization solvent can be used.

The upper part of the cleaning unit 40 is provided with an opening (not shown) for discharging the cleaning liquid while supplying the slurry containing the solid deposited on the bottom of the reaction tank.

Below the cleaning unit 40, a slurry extraction line for taking out a slurry composed of a polymerization solvent and an inorganic solid, and a cleaning liquid supply line (neither shown) for supplying the cleaning liquid are provided. Solids such as by-products purified by the cleaning liquid are taken out from the slurry extraction line.

The static mixing mechanism 41 fixed inside the tubular shape of the cleaning unit 40 repeatedly divides and merges these flows with respect to the downward flow of the solid flowing into the tubular shape and the upward flow of the cleaning liquid. Any static mixing mechanism for stirring can be mentioned, and for example, a static mixer or a mixing mechanism in which a collision plate is provided on the inner wall at an arbitrary angle can be preferably used.

As the static mixer, a reaction mixture containing a solid and an arbitrary shape capable of stirring by changing the flow of the cleaning liquid can be used. For example, one or more spiral twisting blades are provided on the inner wall of the tubular structure portion. Can be used.

The size of the washing portion is not particularly limited, and is appropriately set according to the size of the reaction tank to be connected, the amount of solids such as salts that can be produced as a by-product, the amount of the reaction mixture to be washed, and the like. Can be done. For example, when the amount of by-product salt is large, the degree of cleaning can be increased by extending the length of the tubular structure and the static mixing mechanism stored therein.

Solids, for example salts that by-produce as the polymerization reaction progresses, may be present in the reaction mixture. These solids are dispersed in the solution by stirring with a stirring blade and a moving flow, and sequentially move beyond the partition wall to reach the reaction vessel 1c provided with the washing unit 40. Here, the solid dispersed in the solution is precipitated at the bottom of the reaction vessel 1c according to gravity and the discharge flow from the solid recovery line below the cleaning unit 40, and is cleaned in a wet state or in a slurry state. It descends in the cylinder of the part. On the other hand, the cleaning liquid is supplied from the lower side to the upper side of the cleaning unit 40. In the static mixing mechanism 41 in the cleaning unit 40, the descending solid and the ascending cleaning liquid continuously come into countercurrent contact, and the reaction mixture is countercurrently washed.

The solid purified through the static mixing mechanism 41 is continuously or intermittently discharged from the solid recovery line below the cleaning unit 40. On the other hand, the reaction-treated product and the cleaning liquid from which the solids have been separated and removed are continuously discharged from the cleaning liquid discharge port above the cleaning unit 40, and recovered from the reaction mixture recovery line 7 connected to the side wall 3b. As a result, the polymerization reaction can be continuously carried out in the reaction tank, and the countercurrent washing and discharge of solids such as by-products can be continuously carried out in the washing part. With respect to the recovered reaction mixture, the reaction mixture and the phase separation agent are mixed in the granulation section in the same manner as in the first embodiment, and the granulation step is performed.

In general, the higher the concentration of solids contained in the reaction mixture, the easier it is for these solids to be incorporated into the particles during PAS granulation by cooling. As described above, by having a separation washing step of separating the solid contained in the reaction mixture by sedimentation and performing countercurrent washing before the granulation step, for example, reducing the salt concentration contained in the reaction mixture. Can be done. Therefore, when PAS is granulated by cooling, these solids are less likely to be taken into the particles, and as a result, granular PAS having less impurities can be obtained.

In the third embodiment, points other than the above are as described in the first embodiment.

[Embodiment 4]
Subsequently, another embodiment of the PAS continuous polymerization apparatus will be described with reference to FIG.

Explaining with reference to FIG. 4, the PAS continuous polymerization apparatus 400 includes a first reaction tank 50, a second reaction tank 51, and a third reaction tank 52. The second reaction tank 51 is arranged vertically downward with respect to the first reaction tank 50, and the third reaction tank 52 is arranged vertically downward with respect to the second reaction tank 51.

The first reaction tank 50 and the second reaction tank 51 are connected by a first pipe 65. Further, the second reaction tank 51 and the third reaction tank 52 are connected by a second pipe 67.

An organic polar solvent, a sulfur source and a dihaloaromatic compound are supplied to the first reaction vessel 50 as reaction raw materials, and in the first pipe 65, the reaction mixture in the first reaction vessel 50 exceeds the maximum liquid level. At that time, the reaction mixture is provided so as to move to the second reaction tank 51 through the first pipe 65. Further, in the second pipe 67, when the reaction mixture in the second reaction tank 51 exceeds the maximum liquid level, the reaction mixture moves to the third reaction tank 52 through the second pipe 67. It is provided as follows. Then, the reaction mixture is recovered from the third reaction tank 52, the reaction mixture and the phase separation agent are mixed in the granulation section, and the granulation step is performed. As described above in Embodiment 1, the phase separator may be added to a reaction mixture drawn from a more upstream reaction vessel, eg, a second reaction vessel 51. Alternatively, the reaction mixture may be added directly to any reaction vessel without being extracted.

Further, a ventilation unit 70 is connected to each of the first to third reaction tanks 50 to 52. The first to third reaction tanks 50 to 52 communicate with each other via the gas phase via the ventilation portion 70.

With such a configuration of the PAS continuous polymerization apparatus 400, even if the reaction mixture is sequentially moved by utilizing the height difference of the maximum liquid level of each of the first reaction tank 50 and the second reaction tank 51, the embodiment The same effect as in 1 can be obtained. Further, according to the PAS continuous polymerization apparatus 400, it is not necessary to provide a partition wall as shown in the first embodiment.

Examples are shown below, and embodiments of the present invention will be described in more detail. Of course, the present invention is not limited to the following examples, and it goes without saying that various aspects can be used for details. Furthermore, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims, and the present invention also relates to an embodiment obtained by appropriately combining the disclosed technical means. It is included in the technical scope of the invention.

Method for measuring weight average molecular weight:
The weight average molecular weight (Mw) of the polymer was measured using a high-temperature gel permeation chromatograph (GPC) SSC-7101 manufactured by Senshu Kagaku Co., Ltd. under the following conditions. The weight average molecular weight was calculated as a polystyrene-equivalent value.
Solvent: 1-chloronaphthalene,
Temperature: 210 ° C,
Detector: UV detector (360 nm),
Sample injection volume: 200 μl (concentration: 0.05% by mass),
Flow velocity: 0.7 ml / min,
Standard polystyrene: Five types of standard polystyrene: 616,000, 113,000, 26,000, 8,200, and 600.

[Example]
A PAS continuous polymerization apparatus similar to that shown in FIG. 3 was used except that the containment chamber 2 had 6 reaction tanks formed by being partitioned by 5 partition walls. This PAS continuous polymerization apparatus was a Ti reactor having a semicircular partition wall and dimensions of 100 mm × 300 mm in diameter. After charging 950 g of NMP into the PAS continuous polymerization apparatus, the temperature 1 of the portion separated by the first partition wall and the second partition wall from the upstream side is separated by 180 ° C. and the third partition wall and the fourth partition wall. The temperature 2 of the portion was maintained at 240 ° C., and the NMP-pDCB mixture was 4.61 g / min (NMP: pDCB (weight ratio) = 1317.4: 342), 48 weights, using a metering pump from each supply line. The raw materials were continuously supplied at a flow rate of% NaOH 0.51 g / min and 45 wt% NaSH 0.76 g / min. At the same time, using a distillation apparatus connected to the PAS continuous polymerization apparatus, water was continuously removed from the PAS continuous polymerization apparatus while controlling the pressure to a gauge pressure of 0.32 MPa by a pressure regulating valve, and further, in the removed water. The pDCB was separated in a stationary tank and returned to the PAS continuous polymerization apparatus. Further, the gas from the distillation apparatus was passed through 2 kg of NMP on the downstream side of the pressure regulating valve, and then passed through 5 kg of a 5 mass% sodium hydroxide aqueous solution to completely absorb and recover hydrogen sulfide, and then exhausted.

The polymerization reaction product is continuously overflowed from the reaction tank located at the most downstream in the moving direction of the reaction mixture to the washing section provided at the bottom thereof to precipitate the by-product NaCl in the polymerization reaction product. At the same time, a cleaning NMP heated to 260 ° C. was flowed from the downstream side to the upstream side of the sedimentation of the by-product salt at a flow rate of 2.5 g / min. Thus, the by-product salt was separated by sedimentation, and the by-product salt NaCl was continuously washed in a countercurrent manner with the washing solvent NMP. The reaction mixture from which the by-product salt containing the washing NMP was removed was continuously withdrawn from the reaction mixture recovery line 7. The reaction mixture from which the extracted by-product salt was removed was kept at 255 ° C., and water as a phase separation agent was added to the reaction mixture at a ratio of 0.7 molar parts by mass with respect to 100 parts by mass of NMP in the reaction mixture. And mixed. When the separated phase was slowly cooled from 240 ° C. to 220 ° C. at a rate of 0.2 ° C./min, PAS crystallized.

Further, the mixture was cooled to room temperature, and the crystallized PAS was sieved with a sieve having a mesh size of 38 μm (400 mesh) to separate liquids such as a solvent and residual NaCl, and washed with water. Then, the sieve was sieved with a sieve having a mesh size of 150 μm (100 mesh), and granular PAS having an average particle diameter of 380 μm was obtained from the sieved product.

When the PAS obtained after continuing the above operation for 5 hours was collected and analyzed, the weight average molecular weight Mw of this PPS by GPC was 28,000.

When the obtained granular PAS was supplied to the processing equipment, good processing characteristics were obtained without causing problems of poor biting and powdering.

[Comparison example]
PAS was produced and recovered in the same manner as in Examples except that the phase separating agent was not added and the granulation step was not performed.

The obtained PAS was in the form of a powder having an average particle size of less than 38 μm. When the powdered PAS was supplied to the processing equipment, poor biting and powdering occurred.

1a, 1b, 1c Reaction tank 2 Storage chamber 3a, 3b Side wall 4 Organic polar solvent supply line 5 Sulfur source supply line 6 Dihalo aromatic compound supply line 7 Reaction mixture recovery line 8a, 8b partition wall 9a, 9b, 9c Reaction mixture 10a, 10b, 10c Stirring blade 11 Stirring shaft 12 Rotational drive 13 Exhaust line 14 Dehydration part 15 Organic polar solvent recovery line 16 Steam recovery line 17 Gas-liquid separation part 18 Gas recovery line 19, 24 Reaction raw material separation and recovery part 20 Waste gas line 21 , 26 Reaction raw material resupply line 22, 27 Reaction raw material resupply part 23 Liquid recovery line 25 Waste water line 28 Air supply part 29 Air supply line 30 Granulation part 31 Phase separator supply line 32 Solid recovery line 33 Liquid recovery line 34 Sieve 35 Sieving pass-through recovery line 36 Sieving non-passing-through recovery line 40 Cleaning unit 41 Static mixing mechanism 43 Rotating shaft 44 Reaction vessel 45a, 45b Partition plate 100, 200, 300, 400 Continuous polymerization equipment

Claims (10)

A method for producing polyarylene sulfide.
A supply step of supplying an organic polar solvent, a sulfur source, and a dihaloaromatic compound as reaction raw materials to a continuous polymerization apparatus having a plurality of reaction tanks communicating with each other via a gas phase.
A polymerization reaction step of carrying out a polymerization reaction between the sulfur source and the dihalo aromatic compound in the organic polar solvent in at least one reaction vessel.
A removal step of removing at least a part of water in the gas phase portion of the reaction tank from the reaction tank,
A moving step of sequentially moving the reaction mixture in which the polymerization reaction is proceeding to each reaction vessel is performed in parallel.
Furthermore, a granulation step of adding a phase separator to granulate polyarylene sulfide, and
A method for producing polyarylene sulfide, which comprises a recovery step of recovering the granulated polyarylene sulfide. The method for producing polyarylene sulfide according to claim 1, wherein a separation step for separating the solid contained in the reaction mixture is provided before the granulation step. The method for producing polyarylene sulfide according to claim 1 or 2, wherein a separation washing step of separating the solid contained in the reaction mixture by sedimentation and performing countercurrent washing is provided before the granulation step. .. The production of the polyarylene sulfide according to any one of claims 1 to 3, wherein the recovery step recovers the granulated polyarylene sulfide as a non-passing material of a sieve having a mesh size of 38 μm. Method. The aspect according to any one of claims 1 to 4, wherein the phase separation agent is continuously added to any one of the plurality of reaction tanks before the end of the step of carrying out the polymerization reaction. A method for producing polyarylene sulfide. The method for producing polyarylene sulfide according to any one of claims 1 to 4, wherein the phase separation agent is added to the reaction mixture after removing the reaction mixture from the continuous polymerization apparatus. The method for producing polyarylene sulfide according to claim 6, wherein the reaction mixture is slowly cooled after the phase separation agent is added. The method for producing polyarylene sulfide according to any one of claims 1 to 7, wherein the reaction mixture is placed under polymerization conditions after the phase separation agent is added, and the polymerization reaction is further carried out. The method for producing a polyarylene sulfide according to any one of claims 1 to 8, wherein the phase separating agent is water, lithium chloride, an alkali metal carboxylate, or a mixture thereof. The invention according to any one of claims 1 to 9, wherein at least one of the granulation step and the recovery step is performed in parallel with the supply step, the polymerization reaction step, the removal step and the moving step. The method for producing a polyarylene sulfide according to the above.

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