JP2010100701A - Method for treatment of resin slurry - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for stable treatment of resin slurry by effective heat exchange of the resin slurry. <P>SOLUTION: The method for treatment of resin slurry is characterized by performing the heat exchange using a spiral-type heat exchanger as the heat exchanger when the heat exchange of the resin slurry is performed, wherein polyarylene sulfide resin slurry is preferably heated to 150°C or higher and cooled, followed by performing solid-liquid separation, and the spiral-type heat exchanger is used for the heating and the cooling. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for treating a resin slurry, and more particularly to a heat exchange method for a polyarylene sulfide resin slurry.

  Polyarylene sulfide resin is an engineering plastic with excellent heat resistance, chemical resistance, flame retardancy, mechanical strength, electrical properties, and dimensional stability. Various molding methods such as injection molding, extrusion molding, and compression molding. Therefore, it can be molded into various molded products, films, sheets, fibers and the like, and is widely used in a wide range of fields such as electric / electronic devices and automobile devices.

  Polyarylene sulfide resins are generally used in parts that are used at high temperatures, such as projectors and projection TVs, due to problems such as frequent die maintenance due to substances generated in the mold due to impurities generated during injection molding. There is a problem that the lens is fogged by impurities generated from the arylene sulfide resin, and many studies have been made to reduce these impurities. However, there are few studies that define heat exchange methods and conditions in these studies.

  Patent Document 1 discloses a method in which a polyarylene sulfide resin is subjected to a slurry treatment with hot water at 130 ° C. or higher, followed by solid-liquid separation, and further a slurry treatment with an acid at 130 ° C. or higher.

Patent Document 2 discloses heat exchange of a polyarylene sulfide resin slurry using a double-pipe heat exchanger. Further, as a heat exchange method, there is a description that a closed cycle of a heat exchange medium is used for heating and cooling a part of the processing slurry.
Japanese Patent Laid-Open No. 14-293934 Japanese Patent Publication No. 5-29649

  In the method described in Patent Document 1, impurities in the polyarylene sulfide resin can be reduced. However, there is no description regarding a heat exchange method in slurry processing at a high temperature, and there has been a problem in efficiently performing slurry processing.

  In general, a multi-tube heat exchanger is used as a heat exchanger for heating and cooling the liquid. However, when the polyarylene sulfide resin slurry is heat exchanged using this multi-tube heat exchanger, the polyarylene sulfide resin settles and stays due to the difference in specific gravity between the polyarylene sulfide resin and the solvent, and the slurry concentration locally. As a result, the heat exchanger was clogged due to the rise of the temperature, and there was a problem that stable operation over a long period of time was impossible.

  As measures to prevent blockage in the heat exchanger, it is desirable to make the liquid flow path a single flow path and to reduce the liquid retention part in the heat exchanger as much as possible. However, even when the double-pipe heat exchanger described in Patent Document 2 is used, there are problems such as an increase in liquid residence time and an increase in necessary site area, which is not preferable.

  In view of such problems, the present invention relates to a method for stably treating resin slurries such as polyarylene sulfide resins and stably treating resin slurries, and efficiently removing impurities contained in polyarylene sulfide resins. Let it be an issue.

  It has been found that the above-mentioned problems can be solved by using a spiral heat exchanger in a method for treating a slurry such as polyarylene sulfide resin.

That is, the present invention
(1) A heat treatment is performed using a spiral heat exchanger as a heat exchanger for heat exchange of the resin slurry. (2) The resin slurry is a polyarylene sulfide resin slurry. (1) Resin slurry treatment method according to (1) (3) A slurry treatment method in which a resin slurry is heated to a temperature of 150 ° C. or higher, and after cooling, solid-liquid separation is performed. (1) or (2) resin slurry treatment method according to (1) or (2), wherein the polyarylene sulfide resin is a polyarylene sulfide resin recovered by a flash method after completion of polymerization. (2) The method for treating a resin slurry according to (2) or (3), wherein the spiral heat exchanger is a horizontal spiral heat exchanger. (1) The resin slurry treatment method according to any one of (1) to (4), wherein the resin slurry before heating is heat-exchanged with the heated resin slurry (1) ) To (5).

  According to the present invention, clogging at the time of heat exchange of a resin slurry such as polyarylene sulfide resin can be prevented, and a large amount of processing can be performed with a small necessary site area and low manufacturing cost. Furthermore, by using a spiral heat exchanger, the frequency of collision between particles and tube walls or particles increases during heat exchange, and water-soluble impurities contained in the polyarylene sulfide resin can be efficiently removed. It became.

  The treatment method of the present invention can be applied to various resin slurries, and is particularly suitable for the treatment of polyarylene sulfide resin slurries. Hereinafter, as a typical example, a method for treating a polyarylene sulfide resin will be described.

  The polyarylene sulfide resin is a homopolymer having a repeating unit represented by the following formula as a main structural unit, or

A copolymer comprising the above repeating unit and the following repeating unit of 1 mol or less, preferably 0.3 mol or less, per mol of the repeating unit.

  The polyarylene sulfide resin is obtained by a method of polymerizing a polyhalogenated aromatic compound and a sulfidizing agent in an organic polar solvent. As the sulfidizing agent, alkali metal sulfides can be used.

[Alkali metal sulfide]
Specific examples of the alkali metal sulfide include sodium sulfide, potassium sulfide, lithium sulfide, rubidium sulfide and cesium sulfide. Among them, sodium sulfide is preferably used. These alkali metal sulfides can be used as hydrates or aqueous mixtures or in the form of anhydrides.

  Specific examples of the alkali metal hydrosulfide include, for example, sodium hydrosulfide, potassium hydrosulfide, lithium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, and sodium hydrosulfide is preferably used. These alkali metal hydrosulfides can be used as hydrates or aqueous mixtures, aqueous solutions or in the form of anhydrides.

  There is no particular limitation on the timing of addition of the sulfur source, and it can be introduced into the system at any stage of the pre-process and polymerization process described later, but it is most preferable to introduce it before the polymerization process.

[Polyhalogenated aromatic compounds]
Specific examples of the polyhalogenated aromatic compound include p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4. , 5-tetrachlorobenzene, hexachlorobenzene, 2,5-dichlorotoluene, 2,5-dichloro-p-xylene, 1,4-dibromobenzene, 1,4-diiodobenzene, 1,4-dichloronaphthalene, 1, 5-dichloronaphthalene, 1-methoxy-2,5-dichlorobenzene, 4,4′-dichlorobiphenyl, 3,5-dichlorobenzoic acid, 4,4′-dichlorodiphenyl ether, 4,4′-dichlorodiphenyl sulfone, and 4,4′-dichlorodiphenyl ketone and the like, and among these, p-dichlorobenzene, m-diphenyl Chlorobenzene, o-dichlorobenzene, 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene, 4,4′-dichlorodiphenyl sulfone, 4,4′-dichlorodiphenyl ketone, etc. are preferably used. p-dichlorobenzene is more preferably used. Of course, it is possible to combine two or more different polyhalogenated aromatic compounds into a copolymer, but it is preferable to use a p-dihalogenated aromatic compound as a main component.

  The amount of the polyhalogenated aromatic compound used is 0.1 to 3 mol, preferably 0.5 to 2 mol, preferably 0.5 to 2 mol, based on 1 mol of the sulfur component, from the viewpoint of obtaining a polyarylene sulfide resin having a viscosity suitable for processing. The range is preferably 0.9 to 1.2 mol.

  Although there is no restriction | limiting in particular in the addition time of a polyhalogenated aromatic compound, It is preferable to introduce | transduce into a system before a superposition | polymerization process.

[Organic polar solvent]
Specific examples of the organic polar solvent include N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethyl-2-imidazolidinone, N, N-dimethylacetamide, N, N-dimethylformamide, hexamethyl Examples thereof include phosphoric acid triamide, dimethyl sulfone and tetramethylene sulfoxide. Among them, N-methyl-2-pyrrolidone is preferably used.

  The amount of the organic polar solvent used is such that the amount of the organic polar solvent in the reaction system is from 0.8 to 10 mol, preferably from 2 to 8 mol, more preferably from 3 to 7 mol, per 1 mol of the sulfur component. If the amount of the organic polar solvent is less than the above range, an undesirable reaction tends to occur, and if it exceeds the above range, the degree of polymerization is difficult to increase.

  Although there is no restriction | limiting in particular in the addition time of an organic polar solvent, It is preferable to introduce | transduce into a system before a superposition | polymerization process.

[Polymerization stabilizer]
In the polymerization of the polyarylene sulfide resin, a polymerization stabilizer can be used in order to stabilize the inside of the system and prevent side reactions. The polymerization stabilizer contributes to the stabilization of the polymerization reaction system and can suppress undesirable side reactions. As the polymerization stabilizer, at least one alkali metal salt selected from alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, and alkaline earth metal carbonates can be used in combination. . Of these, alkali metal hydroxides and alkaline earth metal hydroxides are preferred.

Specific examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide and cesium hydroxide. Specific examples of the alkaline earth metal hydroxide include, for example, Examples thereof include calcium hydroxide, strontium hydroxide, barium hydroxide and magnesium hydroxide, and sodium hydroxide is preferably used.
Although there is no restriction | limiting in particular about the introduction time of a polymerization stabilizer, It is preferable to introduce | transduce into a system before a polymerization process. The amount of the alkali metal salt used is in the range of 1 to 2 moles, preferably 1.005 to 1.5 moles, more preferably 1.01 to 1.2 moles per mole of the sulfur component. preferable.

[Polymerization aid]
For the polymerization of the polyarylene sulfide resin, a polymerization aid can be used as necessary. Here, the polymerization aid means a substance having an action of increasing the obtained polymer viscosity.

  Specific examples of such polymerization aids include, for example, organic carboxylates, water, organic sulfonates, alkali metal sulfates, alkaline earth metal oxides, alkali metal phosphates, and alkaline earth metal phosphates. Etc. These can be used alone or in combination of two or more. Of these, organic carboxylates and water are preferably used.

  Specific examples of the organic carboxylate include the formula R (COOM) (wherein R is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group, an alkylaryl group, or an arylalkyl group, and M is lithium. , An alkali metal selected from sodium, potassium, rubidium and cesium). More specifically, lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium benzoate, sodium benzoate, sodium phenylacetate, sodium p-toluate and the like can be mentioned. The organic carboxylate is an organic carboxylic acid and one or more compounds selected from the group consisting of alkali metal hydroxides, alkali metal carbonates and alkali metal bicarbonates in an organic polar solvent, approximately equichemical equivalents each. You may form by adding and making it react. One or more organic carboxylates 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.

  Water is either an organic metal carboxylate hydrate or aqueous solution, an alkali metal sulfide hydrate or aqueous solution, an alkali metal hydrosulfide aqueous solution present in the reaction system, or added directly to the reaction system. Either one or both are acceptable.

  There is no particular limitation on the timing of introducing the polymerization aid into the system, and it can be introduced into the system at any stage of the previous process or the polymerization process.

  The amount of the polymerization aid used is preferably 0.01 to 20 mol with respect to 1 mol of the sulfur component, more preferably 0.04 to 15 mol with respect to 1 mol of the sulfur component. Preferably it is 0.07 mol to 15 mol with respect to 1 mol of sulfur components. When the amount is less than 0.01 mol, the effect of increasing the polymer viscosity cannot be obtained, and when the amount is more than 20 mol, the polymerization rate is lowered and the productivity is deteriorated.

[pre-process]
Prior to the polymerization step, a sulfur source, a polyhalogenated aromatic compound and an organic polar solvent, a polymerization stabilizer and a polymerization aid as necessary are added, and preferably in an inert gas atmosphere at room temperature to 220 ° C. A dehydration reaction may be performed to adjust the amount of water in the reaction system.

  The amount of water in the reaction system referred to here is an amount obtained by subtracting the amount of water removed from the reaction system from the amount of water introduced into the reaction system as an aqueous solution and hydrate when the raw materials are charged. This amount is not particularly limited, but is preferably in the range of 0 to 2 moles with respect to 1 mole of the charged sulfur component, from the viewpoint of polymerization rate and by-product suppression.

[Polymerization process]
The polymerization temperature is not particularly limited, but is preferably 210 ° C to 300 ° C, more preferably 220 ° C to 290 ° C, and further preferably 225 ° C to 285 ° C. When the polymerization temperature is lower than 210 ° C., the polymerization becomes insufficient, and the desired polyarylene sulfide resin cannot be obtained. When the polymerization temperature is higher than 300 ° C., decomposition occurs, which is not preferable.

  The polymerization time is not particularly specified because it varies widely depending on other reaction conditions, but is generally 0.01 hours to 10 hours, preferably 0.2 hours to 7 hours, more preferably 0.5 hours to 5 hours. Is within the range. When the polymerization time is shorter than 0.01 hours, the degree of polymerization does not increase, and when it is longer than 10 hours, the productivity is deteriorated, which is not preferable.

  This polymerization is generally preferably carried out under an inert atmosphere such as nitrogen.

[Recovery method]
The polyarylene sulfide resin recovers solids from a polymerization reaction product containing a polymer, a solvent and the like after the completion of polymerization. There are roughly two types of recovery methods: a flash method and a quench method described later.

The flash method is a method of recovering the solvent by evaporating the solvent and simultaneously recovering the solid matter, and the recovery time can be made relatively short. Therefore, the flash method is an economical recovery method.
On the other hand, the quench method is a method of removing the polymerization reaction product and recovering the particulate polyarylene sulfide resin.

  However, the recovery method of the polyarylene sulfide resin used in the present invention is not limited to either, and either recovery method may be used. However, in view of economy and performance, it is industrially advantageous to use a material recovered by the flash method.

  Since the solid collected by the flash method contains a large amount of by-products together with the polymer, the polymer can be obtained by slurrying with water and then solid-liquid separation. The slurry concentration at this time is preferably more water, but is usually 5 to 20% by mass, preferably 10 to 15% by mass. Following this treatment, it is preferred to wash several times with water or warm water.

[Slurry treatment]
After the polymerization, the polyarylene sulfide resin is slurried and the slurry treatment of the present invention is performed. Slurry with water, an acidic or basic aqueous solution and an organic polar solvent used during polymerization is performed as a solvent used for the slurry treatment, and any solvent may be used as long as it satisfies the requirements of the present invention. Specific examples of the acid include acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, silicic acid, carbonic acid, and propyl acid. Among them, acetic acid and hydrochloric acid are more preferably used, but polyarylene sulfide resin such as nitric acid is decomposed and deteriorated. What is to be made is not preferred. Examples of the base include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide and other alkali metal hydroxides, beryllium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, water Examples include alkali metal earths such as barium oxide, and alkali metal earth oxides such as beryllium oxide, magnesium oxide, calcium oxide, strontium oxide, and barium oxide. Among these, alkali metal hydroxides are more preferably used. Hereinafter, slurry processing using water will be described as a typical example. The water used is preferably distilled water or deionized water. The slurry concentration in the slurry treatment is preferably higher in water, but usually a slurry concentration of 5 to 20% by mass, preferably 10 to 15% by mass is selected.

  In the slurry treatment, solid-liquid separation is performed after heating and cooling in order to efficiently remove impurities contained in the resin. It is preferable that the resin slurry at 10 ° C. to 80 ° C. is heated to 150 ° C. to 250 ° C. under a pressure that does not boil, cooled to 30 ° C. to 100 ° C., and then solid-liquid separated. The heating temperature is more preferably 160 ° C. or higher, further preferably 170 ° C. or higher, and particularly preferably 180 ° C. or higher. A heating temperature of less than 150 ° C. is not preferable because the effect of removing impurities in the polymer is small. Moreover, 250 degrees C or less is preferable and 220 degrees C or less is still more preferable. If the temperature at which solid-liquid separation is performed exceeds 100 ° C., it is not preferable in that water evaporates, and cooling to less than 30 ° C. is not preferable because of poor efficiency.

  Impurities can be efficiently removed by setting the particle size of the polyarylene sulfide resin contained in the slurry to 3 mm or less, and a particle size of 1 mm or less is particularly preferable.

  The holding time after heating is not particularly limited, but a sufficient effect can be obtained by holding for 0.1 minutes or more. The upper limit of the holding time is preferably 1 hour or less from the viewpoint of productivity.

  The treated slurry can be subjected to solid-liquid separation to obtain a polymer. When performing solid-liquid separation, it is preferable to cool the mixture to 100 ° C. or lower. Following this treatment, it is preferred to wash several times with water or warm water. In addition, since the decomposition and oxidation of the end groups are not preferable, the treatment atmosphere is desirably an inert atmosphere in order to avoid this. In the slurry treatment in the present invention, there is no limitation on the combination of slurry treatments depending on the number of treatments or the difference in solvent, water, order of aqueous acid solution, water, order of aqueous acid solution, order of basic aqueous solution, organic polar solvent, water. In order, slurry treatment performed in order of organic polar solvent, acidic aqueous solution, organic polar solvent, acidic aqueous solution, basic aqueous solution, water, acidic aqueous solution, or water, acidic aqueous solution, basic aqueous solution in this order. Most preferably, slurry treatment is performed.

  In these heating and cooling operations, it is important to use a spiral heat exchanger in the present invention.

[Spiral heat exchanger]
In general, spiral heat exchangers have a vertical type and a horizontal type, and the two-fluid flow paths for heat exchange are both single and spiral flow paths, and heat exchange is performed in countercurrent. It is common. Features of the spiral heat exchanger are as follows: (1) Low external fluid flow due to low temperature fluid flowing on the outermost periphery, (2) Since the flow path curve is continuous, the fluid tends to generate turbulent flow, Compared with the fluid flowing through the pipe, the heat transfer performance is significantly improved. (3) Since it is a single flow path, even if clogging occurs, the cross-sectional area of the clogged portion is reduced, thereby increasing the flow velocity and removing clogging. Self-cleaning action works. For the treatment of the resin slurry of the present invention, a horizontal spiral heat exchanger having a large self-cleaning action is preferable.

  FIG. 1 is a conceptual diagram of a horizontal spiral heat exchanger. Reference numeral 1 is a flow path for a low-temperature fluid, 2 is a flow path for a high-temperature fluid, 3 is a flow path interval, and 4 is a flow path width. Spiral heat exchangers are generally commercially available, and these commercially available products can be used in the present invention. Examples thereof include KSH-1H type manufactured by Croce.

  In the present invention, the liquid channel interval is 6 mm or more, preferably 8 to 10 mm, and the channel interval of 6 mm or more is preferable because blockage of the channel due to slurry clogging can be prevented. The average flow rate of the liquid is preferably 0.25 m / sec or more, the flow state becomes turbulent, and the impurities contained in the resin can be efficiently removed by collision between the particles and collision between the particles and the tube wall. More preferably, it is ˜1 m / sec. It is preferable that the average flow rate be 1 m / second or less because the resin slurry can be processed with high heat exchange efficiency. It is preferable to set it to 0.25 m / sec or more because slurry clogging can be prevented.

  As materials used for the spiral heat exchanger, austenitic stainless steel such as JIS standard SUS304, SUS316, SUS316L, austenitic-ferritic stainless steel such as SUS329J1, SUS329J2L, SUS329J4L, Carpenter (registered trademark), Hastelloy (registered trademark), Although titanium etc. are mentioned, JIS specification SUS329J1, SUS329J4L or a carpenter is preferable.

[Heat exchange method]
In general, when the slurry is heated and cooled, it is preferable to use two heat exchangers to heat and cool the slurry and use one for heating and the other for cooling. In this case, it is necessary to supplement or take away the total energy during heating or cooling of the slurry by the heat exchange medium, which is not preferable from the viewpoint of energy consumption. As shown in FIG. 2, four spiral heat exchangers are used, two are used for heating and the other two are used for cooling. The part can be recycled and heat exchange can be performed efficiently. In the first heat exchanger, the slurry was heat-exchanged with the heated heat medium with the slurry heated in the third group, and heated in a boiler or the like in the second heat exchanger. Heat is exchanged with the heat medium and heated to 150 ° C or higher. In the third heat exchanger, the slurry heated in the second unit and the heat medium deprived of heat in the first unit exchange heat, and in the fourth heat exchanger, the slurry exchanges heat with the refrigerant. And can be cooled to 100 ° C. or lower.

  In the present invention, it is preferable to use three spiral heat exchangers in the slurry treatment of the polyarylene sulfide resin in terms of efficient use of energy. As shown in FIG. 3, in the first heat exchanger, the slurry before heating was heat-exchanged with the slurry heated to 150 ° C. or higher, and was heated in the first heat exchanger in the second heat exchanger. The slurry can be heat exchanged with a heat medium and heated to 150 ° C. or higher. The slurry heated to 150 ° C. or higher is heat-exchanged with the slurry before heating as the first high-temperature fluid and cooled, and then heat-exchanged with the refrigerant in the third heat exchanger to 100 ° C. or lower. It is preferable to cool and perform solid-liquid separation. For solid-liquid separation, centrifugation or filtration using a filter cloth is preferred.

[Slurry-treated resin slurry]
The polyarylene sulfide resin obtained by solid-liquid separation of the polyarylene sulfide resin slurry subjected to the slurry treatment by the method of the present invention has sufficiently reduced impurities, and the polyarylene sulfide resin composition and the polyarylene sulfide fiber It can be suitably used as a raw material for polyarylene sulfide films.

  Examples Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the description of these examples.

[Amount of generated gas]
The polyphenylene sulfide resin was dried in a vacuum oven at 130 ° C. for 3 hours, and 3 g of the polyphenylene sulfide resin was sealed in a glass ampoule tube. One side of the glass ampule tube (the one with the polyphenylene sulfide resin) is left in a ceramic electric tubular furnace: ARF-30K (manufactured by Asahi Rika Seisakusho) set at 320 ° C. for 2 hours, and then the non-heated part of the glass ampule tube Cut off about 10 cm from the tip (the one without polyphenylene sulfide resin). From the difference between the initial weight of the cut glass ampule tube and the weight of the glass tube dried at 60 ° C. for 3 hours after washing the components agglomerated and adhered to the glass ampule tube with 5 g of chloronaphthalene, The amount of substances generated from the polyphenylene sulfide resin after 2 hours was calculated. Finally, a value obtained by dividing the obtained amount of generated substance by the initial amount of polyphenylene sulfide resin 3 g was calculated as the amount of generated gas.

Reference Example To an autoclave having a stirrer and a valve at the bottom, 8267.37 g (70.00 mol) of a 47.5 wt% sodium hydrosulfide aqueous solution, 2924.98 g (70.20 mol) of a 96 wt% sodium hydroxide aqueous solution, N-methyl-2-pyrrolidone (NMP) 13860.00 g (140.00 mol), sodium acetate 2187.11 g (26.67 mol), and 10500.00 g of ion-exchanged water were charged at 240 ° C. while passing nitrogen at normal pressure. After gradually heating to about 3 hours and distilling water 1474.16 g and 280.00 g of NMP, the reaction vessel was cooled to 160 ° C. The residual water content in the system per 1 mol of the charged alkali metal sulfide was 1.08 mol including the water consumed for the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.023 mol per mol of the alkali metal sulfide charged.

  Next, 10254.40 g (69.76 mol) of p-dichlorobenzene (p-DCB) and 65451.83 g (65.17 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and stirred at 240 rpm. The temperature was raised from 200 ° C. to 250 ° C. at a rate of 0.8 ° C./min, and held at 250 ° C. for 70 minutes. Next, the temperature was raised from 250 ° C. to 278 ° C. at a rate of 0.8 ° C./min, and maintained at 278 ° C. for 78 minutes. The extraction valve at the bottom of the autoclave was opened, and the contents were flushed into a vessel equipped with a stirrer over 15 minutes while being pressurized with nitrogen, and stirred for a while at 250 ° C. to remove most of NMP.

  The obtained solid and 76 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, washed at 70 ° C. for 30 minutes, and then suction filtered through a glass filter. Subsequently, 76 liters of ion-exchanged water heated to 70 ° C. was poured into a glass filter and suction filtered to obtain a polyphenylene sulfide resin.

Example 1
The polyphenylene sulfide resin obtained in the reference example was slurried with water and adjusted to 15% by mass. In order to heat the adjusted slurry from 70 ° C. to 195 ° C., a horizontal spiral heat exchanger with a channel interval of 10 mm ( Model KSH-1H manufactured by Kurose Co., Ltd.) was used, and a slurry of polyphenylene sulfide resin was passed as shown in FIG. 3 under the condition of an average flow rate of 0.4 m / sec. The heating time to 195 ° C. was 0.5 minutes, and the heat transfer area required for heating was 12 m ² . The cooled slurry was solid-liquid separated and then dried to obtain a polyphenylene sulfide resin. The amount of gas generated in the obtained polyphenylene sulfide resin was 0.73% by weight.

Comparative Example 1
In order to heat the slurry containing 15% by mass of the polyphenylene sulfide resin from 70 ° C. to 195 ° C., a double tube heat exchanger having an inner diameter of 40 mm was used, and the slurry of the polyphenylene sulfide resin had an average flow rate of 0.4 m / second. Under the conditions, the solution was passed as shown in FIG. 4 to perform heat exchange. During the heating up to 195 ° C., clogging occurred in the double-pipe heat exchanger, making continuous operation difficult.

Comparative Example 2
In order to heat the slurry containing 15% by mass of the polyphenylene sulfide resin from 70 ° C. to 195 ° C., a double tube type heat exchanger having an inner diameter of 40 mm was used, and the slurry of the polyphenylene sulfide resin had an average flow rate of 1.3 m / sec. Under the conditions, the solution was passed as shown in FIG. 4 to perform heat exchange. The heating time to 195 ° C. was 5 minutes, and the heat transfer area required for heating was 60 m ² . The cooled slurry was solid-liquid separated and then dried to obtain a polyphenylene sulfide resin. The amount of gas generated in the obtained polyphenylene sulfide resin was 0.75% by weight.

It is a conceptual diagram of a horizontal spiral heat exchanger. It is a figure which shows the processing flow of the resin slurry using four horizontal spiral type heat exchangers. It is a figure which shows the processing flow of the resin slurry using three horizontal spiral heat exchangers. It is a figure which shows the processing flow of the resin slurry using a double tube type heat exchanger.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Low temperature fluid flow path 2 High temperature fluid flow path 3 Flow path spacing 4 Flow path width 5 Horizontal spiral heat exchanger 6 Resin slurry 7 Heat medium 8 Refrigerant 9 Double pipe heat exchanger

Claims (6)

A heat treatment for resin slurry, wherein a heat exchange is performed using a spiral heat exchanger as a heat exchanger. 2. The method for treating a resin slurry according to claim 1, wherein the resin slurry is a polyarylene sulfide resin slurry. 3. A slurry processing method in which a resin slurry is heated to a temperature of 150 [deg.] C. or higher, cooled and then solid-liquid separated, and a spiral heat exchanger is used for heating and cooling. Method for treating resin slurry. 4. The method for treating a resin slurry according to claim 2, wherein the polyarylene sulfide resin is a polyarylene sulfide resin recovered by a flash method after completion of polymerization. The method for treating a resin slurry according to any one of claims 1 to 4, wherein the spiral heat exchanger is a horizontal spiral heat exchanger. The resin slurry treatment method according to any one of claims 1 to 5, wherein heat exchange is performed on the resin slurry before heating with the heated resin slurry.

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