JP2023152968A - Polyarylene sulfide and polyarylene sulfide production method - Google Patents

Abstract

To provide efficiently and in short time, PAS which is excellent in reactivity with a different material and strength, causes less contamination of a metal mold in molding, and is excellent in molding cycle.SOLUTION: There is provided a polyarylene sulfide in which a chloroform extraction component amount is 0.5 wt.% or more and 2.0 wt.% or less. In the polyarylene sulfide, a melt flow rate which is according to ASTM D 1238-70, and is measured in a condition of 315°C and a load of 5000 g, is 5 g/10 minutes or more and 300 g/10 minutes or less, and a temperature fall crystallization temperature measured by a differential scan calorimeter (DSC) at a temperature fall speed of 20°C/min is 190°C or more and 230°C or less. In addition, in the polyarylene sulfide, a carboxyl group inclusion amount is 35 μmol/g or more and 100 μmol/g or less.SELECTED DRAWING: None

Description

The present invention relates to a high viscosity polyarylene sulfide (hereinafter abbreviated as PAS) that has a low oligomer content, a high functional group content, and a high cooling crystallization temperature, and a method for efficiently producing the same.

PAS, represented by polyphenylene sulfide (hereinafter abbreviated as PPS), has properties suitable for engineering plastics, such as excellent heat resistance, gas barrier properties, moldability, chemical resistance, electrical insulation properties, and heat and humidity resistance. It is used mainly for injection molding, extrusion molding, various electrical/electronic parts, mechanical parts, automobile parts, films, textiles, etc. Due to its excellent properties, PAS has been used in a wide range of applications in recent years. PAS used in these applications is required to be a high molecular weight PAS due to its excellent mechanical properties. In addition, a high functional group content is required from the viewpoint of reactivity with different materials, a low oligomer content is required from the viewpoint of reducing mold fouling and mold vent clogging, and a high content is required from the viewpoint of improving productivity by shortening the molding cycle. There has been a strong demand for PAS that has both cooling and crystallization temperatures.

As a typical method for producing PAS, as described in Patent Document 1, in an organic amide solvent such as N-methyl-2-pyrrolidone, a sulfidating agent such as sodium sulfide and a dihalogenating agent such as p-dichlorobenzene are used. A method of reacting with an aromatic compound has been proposed.

On the other hand, in order to obtain a high molecular weight PAS during polymerization, Patent Document 2 discloses a method in which an alkali metal carboxylate is used as a polymerization aid and water is pressurized into a polymerization container during the polymerization.

Patent Documents 3 to 6 propose production methods in which a trihalogenated aromatic compound is added during polymerization in order to obtain high molecular weight PAS. Patent Document 3 discloses a method in which a sulfidating agent and a halogenated aromatic compound are reacted under reflux using a three-necked flask to remove water in the polymerization system. Patent Document 4 discloses a method in which water is used as a polymerization aid and 1.00 to 5.00 mol% of a trihalogenated aromatic compound is reacted with 1.00 mol of a sulfidating agent. . Further, Patent Document 5 describes a method of adding a thiol compound having one or more modifying groups selected from amino groups and carboxy groups and one or more mercapto groups as a modifying agent for the purpose of introducing a functional group. Proposed. Further, Patent Document 6 discloses a method in which a sulfidating agent is reacted with a dihalogenated aromatic compound and a p-dihaloalkyl-substituted aromatic compound, and after recovery, washing is performed with hot water and acetone.

Special Publication No. 45-3368 Special table 2019-522099 publication Japanese Unexamined Patent Publication No. 61-47734 Japanese Patent Application Publication No. 2016-108488 JP 2021-147513 Publication Japanese Unexamined Patent Publication No. 1-188529

However, since the PAS described in Patent Document 1 has a low molecular weight, there was a problem in the strength of a molded product obtained by molding the obtained PAS. In addition, in examples using trihalogenated aromatic compounds, the blending amount is large and there is a problem in the molding processability of the obtained PAS. Although the PAS described in Patent Document 2 can be expected to have a relatively high molecular weight, it has a low functional group content and has a problem in reactivity with different materials. In addition, it was necessary to inject water during the polymerization, making the process complicated and not simple. The PAS described in Patent Document 3 can be expected to have a relatively high molecular weight, but since it is not washed with an organic solvent, the obtained PAS has a large amount of oligomers, which may cause mold stains and mold vent clogging during molding. There are concerns. Furthermore, since water in the polymerization system is removed, it takes a long time to obtain high molecular weight PAS, resulting in low productivity. In the method for producing PAS described in Patent Document 4, high molecular weight PAS can be obtained in a short time, but the blended amount of trihalogenated aromatic compounds is large, and when the obtained PAS is heated and melted, it becomes gelatinous and becomes difficult to mold. I have a sexual problem. In the method for producing PAS described in Patent Document 5, a relatively high functional group content can be expected, but since the added modifier acts as a polymerization terminator, there is a problem that the molecular weight of the obtained PAS is low. Although the PAS described in Patent Document 6 can be expected to have a low oligomer content and a high molecular weight, the cooling-down crystallization temperature is low, and problems remain in molding cycleability during injection molding. As described above, the PAS described in Patent Documents 1 to 6 had a problem in that it was difficult to have all of a low oligomer content, a high functional group content, a high cooling crystallization temperature, and a high molecular weight.

As a result of intensive studies to solve these problems, the present invention has been developed by combining a sulfidating agent and a predetermined amount of a dihalogenated aromatic compound and a trihalogenated aromatic compound in an organic polar solvent in the presence of a predetermined amount of a polymerization aid. We have discovered that by performing a specific post-treatment after the completion of the reaction polymerization step, it is possible to obtain PAS that has a low oligomer content, a high functional group content, a high cooling crystallization temperature, and a high molecular weight, which led to the present invention. Ta.

That is, the present invention is as follows.
1. A polyarylene sulfide with a chloroform extractable content of 0.5% by weight or more and 2.0% by weight or less, which has a melt flow rate measured at 315°C and a load of 5000g in accordance with ASTM D 1238-70. 5g/10 minutes or more and 300g/10 minutes or less, the cooling crystallization temperature measured by a differential scanning calorimeter (DSC) at a cooling rate of 20°C/min is 190°C or more and 230°C or less, and the carboxyl group content is is 35 μmol/g or more and 100 μmol/g or less.
2. 3. The polyarylene sulfide according to 1, which has a dispersity expressed by weight average molecular weight/number average molecular weight of 5.5 or more and 15.0 or less. A method for producing polyarylene sulfide in which a sulfidating agent, a dihalogenated aromatic compound, and a trihalogenated aromatic compound are reacted in the presence of an alkali metal hydroxide and an alkali metal carboxylate in an organic polar solvent, at least the following: 3. The method for producing polyarylene sulfide according to 1 or 2, characterized in that steps 1 to 4 are carried out.
Step 1: In an organic polar solvent, 0.06 mol or more and 0.29 mol or less of an alkali metal carboxylate are present with respect to 1.00 mol of the sulfidating agent, and dihalogenation is performed with respect to 1.00 mol of the sulfidating agent. Presence of an aromatic compound of 0.99 mol or more and 1.03 mol or less and a trihalogenated aromatic compound of 0.10 mol% or more and 1.00 mol% or less, and reacting within a temperature range of 200°C or more and 280°C or less Polyarylene sulfide polymerization process.
Step 2: A step of distilling off the organic polar solvent from the mixture obtained at the end of the reaction to obtain a solid containing polyarylene sulfide.
Step 3: Following Step 2, the solid material containing polyarylene sulfide is washed with water and then treated with an acid.
Step 4: Following Step 3, a step of washing polyarylene sulfide with an organic solvent.
4. 4. The method for producing polyarylene sulfide according to 3, wherein in step 1, water is present in the reaction vessel in an amount of 0.50 mol or more and 1.50 mol or less per 1.00 mol of the sulfidating agent.
5. 4. The method for producing polyarylene sulfide according to 3 or 4, wherein in step 1, the polymerization time including temperature increase/decrease time within a temperature range of 200° C. or more and 280° C. or less is 120 minutes or more and 240 minutes or less. .
6. 6. The method for producing polyarylene sulfide according to any one of 3 to 5, characterized in that, subsequent to step 4, a heat treatment step of heat-treating the polyarylene sulfide is performed.

According to the present invention, it is possible to efficiently obtain a PAS that has excellent reactivity with different materials and strength, has little mold staining during molding, and has excellent molding cycleability.

Embodiments of the present invention will be described in detail below.

The PAS in the present invention is a homopolymer or copolymer whose main constituent unit is a repeating unit of the formula -(Ar-S)-, preferably containing 80 mol% or more of the repeating unit. Ar includes units represented by the following formulas (A) to (K), among which formula (A) is particularly preferred.

(R1 and R2 are substituents selected from hydrogen, an alkyl group, an alkoxy group, and a halogen group, and R1 and R2 may be the same or different.)

This repeating unit is the main structural unit, and includes branching units or crosslinking units represented by the following formulas (L) to (N). The copolymerization amount of these branching units or crosslinking units is preferably in the range of 0.10 mol % or more and 1.00 mol % or less based on 1 mol of -(Ar-S)- units. From the viewpoint of obtaining a high molecular weight PAS, the lower limit of the copolymerization amount of branched units or crosslinked units is preferably 0.10 mol% or more, more preferably 0.20 mol% or more, and even more preferably 0.30 mol% or more. On the other hand, from the viewpoint of preventing gelatinization of the polymer, the upper limit of the amount of copolymerization of branching units or crosslinking units is preferably 1.00 mol% or less, more preferably 0.80 mol% or less, and 0.60 mol%. The following are more preferred.

Moreover, the PAS in the present invention may be a random copolymer, a block copolymer, or a mixture thereof containing the above repeating units.

Typical examples of these include polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, random copolymers and block copolymers thereof, and mixtures thereof. Particularly preferable PASs include p-phenylene sulfide units shown below as main constituent units of the polymer.

を８０モル％以上、特に９０モル％以上含有するポリフェニレンスルフィド樹脂が挙げられる。

Examples include polyphenylene sulfide resins containing 80 mol% or more, particularly 90 mol% or more.

The method for manufacturing PAS of the present invention will be specifically explained below.

First, the raw materials used for producing PAS will be explained.

[Sulfiding agent]
The sulfidating agent used in the present invention may be any agent that can introduce a sulfide bond into a halogenated aromatic compound, and examples thereof include alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide.

Specific examples of alkali metal sulfides include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, and mixtures of two or more of these, with lithium sulfide and/or sodium sulfide being preferred. Sodium sulfide is more preferably used. These alkali metal sulfides can be used as hydrates or aqueous mixtures or in anhydrous form. Note that the aqueous mixture refers to an aqueous solution, a mixture of an aqueous solution and a solid component, or a mixture of water and a solid component. Since commonly available and inexpensive alkali metal sulfides are hydrates or aqueous mixtures, it is preferable to use alkali metal sulfides in such a form.

Specific examples of alkali metal bisulfides include lithium bisulfide, sodium bisulfide, potassium bisulfide, rubidium bisulfide, cesium bisulfide, and mixtures of two or more of these. Among them, lithium bisulfide and /Or sodium bisulfide is preferred, and sodium bisulfide is more preferably used.

Furthermore, an alkali metal sulfide prepared in a reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can also be used. Furthermore, an alkali metal sulfide prepared by contacting an alkali metal hydrosulfide and an alkali metal hydroxide in advance can also be used. These alkali metal hydrosulfides and alkali metal hydroxides can be used as hydrates or aqueous mixtures, or in anhydrous form, and hydrates or aqueous mixtures are preferred from the viewpoint of availability and cost. preferable.

Furthermore, an alkali metal sulfide prepared in a reaction system from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide can also be used. Alternatively, an alkali metal sulfide prepared in advance by contacting an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide with hydrogen sulfide can also be used. Hydrogen sulfide may be used in any of the following forms: gaseous, liquid, or aqueous.

[Dihalogenated aromatic compound]
Dihalogenated aromatic compounds are used in producing the PAS of the present invention. The dihalogenated aromatic compounds used include p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dibromobenzene, o-dibromobenzene, m-dibromobenzene, 1-bromo-4-chlorobenzene, and 1-bromobenzene. -Dihalogenated benzenes such as 3-chlorobenzene, and 1-methoxy-2,5-dichlorobenzene, 1-methyl-2,5-dichlorobenzene, 1,4-dimethyl-2,5-dichlorobenzene, 1,3- Dihalogenated aromatics containing substituents other than halogens such as dimethyl-2,5-dichlorobenzene, 2,5-dichlorobenzoic acid, 3,5-dichlorobenzoic acid, 2,5-dichloroaniline, and 3,5-dichloroaniline Examples include group compounds. Among these, dihalogenated aromatic compounds containing p-dihalogenated benzene as a main component, typified by p-dichlorobenzene, are preferred. From the viewpoint of preventing depolymerization of PAS during polymerization, the lower limit of the amount of the dihalogenated aromatic compound is preferably 0.99 mol or more, more preferably 1.00 mol or more per 1.00 mol of the sulfidating agent. preferable. From the viewpoint of obtaining a high molecular weight PAS, the upper limit of the amount of the dihalogenated aromatic compound is preferably 1.03 mol or less, more preferably 1.02 mol or less, per 1.00 mol of the sulfidating agent. The dihalogenated aromatic compound may be used alone or as a mixture of two or more different types.

[Branching/crosslinking agent]
When producing the PAS of the present invention, one of the preferred embodiments is to use a branching/crosslinking agent. Specifically, 1,3,5-trichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, hexachlorobenzene, 1,4, Polyhalogenated aromatic compounds with three or more halogens, such as 6-trichloronaphthalene, and 2,3,6-trichlorobenzoic acid, 2,4,5-trichlorobenzoic acid, 2,4,6-trichlorobenzoic acid Examples include polyhalogenated aromatic compounds containing substituents other than halogen and having three or more halogens, such as , 2,3,4-trichloroaniline, and 2,4,6-trichloroaniline. Among them, trihalogenated aromatic compounds typified by 1,3,5-trichlorobenzene and 1,2,4-trichlorobenzene are preferred from the viewpoint of increasing the cooling-down crystallization temperature of the resulting PAS. When using a trihalogenated aromatic compound as a branching/crosslinking agent, from the viewpoint of increasing the molecular weight of PAS, the blending amount of the trihalogenated aromatic compound is 0.10 mol% per 1.00 mol of the sulfidating agent. It is preferable to have the amount present in an amount of 0.20 mol % or more, more preferably 0.30 mol % or more. On the other hand, from the viewpoint of preventing gelation of the polymer due to increased branching and crosslinking, the amount of the trihalogenated aromatic compound should be 1.00 mol % or less with respect to 1.00 mol of the sulfidating agent. is preferable, 0.80 mol% or less is more preferable, 0.60 mol% or less is even more preferable, and even more preferably 0.50 mol% or less. One type of branching/crosslinking agent may be used, or a mixture of two or more different types may be used.

[Organic polar solvent]
In the present invention, an organic polar solvent is used as the polymerization solvent. Preferred examples of the organic polar solvent to be used include organic amide solvents. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone, caprolactams such as N-methyl-ε-caprolactam, 1, Aprotic organic solvents such as 3-dimethyl-2-imidazolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, hexamethylphosphoric acid triamide, etc., and mixtures thereof, have high reaction stability. It is preferably used for. Among these, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone are preferred, and N-methyl-2-pyrrolidone is more preferably used.

The amount of the organic polar solvent used is 2.00 to 10.00 mol, preferably 2.25 to 6.00 mol, more preferably 2.50 to 5.50 mol per 1.00 mol of the sulfidating agent. The range is selected.

[Polymerization aid]
It is also one of the preferred embodiments to use a polymerization aid in order to obtain PAS with a relatively high molecular weight in a shorter time. Here, the polymerization aid means a substance that has the effect of increasing the viscosity of the obtained PAS. Specific examples of such polymerization aids include organic carboxylates, water, alkali metal chlorides, organic sulfonates, alkali metal sulfates, alkaline earth metal oxides, alkali metal phosphates, and alkaline earth metal oxides. Examples include similar metal phosphates. These may be used alone or in combination of two or more. Among these, organic carboxylates, water, and alkali metal chlorides are preferred, and the organic carboxylates are preferably alkali metal carboxylates, and the alkali metal chlorides are lithium chloride.

The alkali metal carboxylate has the general formula R(COOM) _n (wherein R is an alkyl group, cycloalkyl group, aryl group, alkylaryl group, or arylalkyl group having 1 to 20 carbon atoms. M is an alkali metal selected from lithium, sodium, potassium, rubidium and cesium; n is an integer from 1 to 3). Alkali metal carboxylates can also be used as hydrates, anhydrides or aqueous solutions. Specific examples of alkali metal carboxylates include lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, sodium benzoate, sodium phenylacetate, potassium p-toluate, and mixtures thereof. can be mentioned.

An alkali metal carboxylate is produced by adding approximately equal chemical equivalents of an organic acid and one or more compounds selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates and reacting them. It may be synthesized by Among the alkali metal carboxylates mentioned above, lithium salts have high solubility in the reaction system and have a large auxiliary effect, but are expensive. On the other hand, since potassium, rubidium, and cesium salts are thought to have insufficient solubility in the reaction system, sodium acetate, which is inexpensive and has appropriate solubility in the polymerization system, is most preferably used.

The water used as the polymerization aid is preferably distilled water or ion-exchanged water so as not to impair the preferable chemical modification effect of PAS.

In the present invention, it is preferable to use an alkali metal carboxylate as a polymerization aid, and it is more preferable to use sodium acetate. As the lower limit of the polymerization aid, it is preferable that the polymerization aid be present in an amount of 0.06 mole or more per 1.00 mole of the sulfidizing agent. From the viewpoint of increasing the molecular weight, it is more preferably 0.10 mol or more, and even more preferably 0.15 mol or more. Furthermore, the upper limit of the polymerization aid is preferably present in an amount of 0.29 mol or less, more preferably 0.27 mol or less, and even more preferably 0.25 mol or less per 1.00 mol of the sulfidating agent. Exceeding the above-mentioned preferred range is not preferred because the burden of wastewater treatment increases.

Further, when water is used as a polymerization aid, it is preferable that water be present in the reaction vessel in an amount of 0.50 mol or more per 1.00 mol of the sulfidating agent. In the sense of obtaining a higher molecular weight, it is more preferably 0.60 mol or more, and even more preferably 0.70 mol or more. When using water as a polymerization aid, the upper limit for water per 1.00 mol of sulfidating agent is is preferably present in an amount of 1.50 mol or less, more preferably 1.25 mol or less, and even more preferably 1.00 mol or less.

It is of course possible to use two or more of these polymerization aids in combination. For example, when an alkali metal carboxylate and water are used together, it is possible to increase the molecular weight with a smaller amount of the alkali metal carboxylate and water.

There is no particular specification regarding the timing of addition of these polymerization aids, and they may be added at any time during the pre-process, at the start of polymerization, or during the polymerization process, which will be described later, or may be added in multiple portions. When using an alkali metal carboxylate as a polymerization aid, it is more preferable to add it simultaneously with other additives at the start of the previous step or at the start of polymerization, from the viewpoint of ease of addition. When water is used as a polymerization aid, it is effective to add it during the polymerization process after adding the dihalogenated aromatic compound and the branching/crosslinking agent.

[Polymerization stabilizer]
A polymerization stabilizer can also be used to stabilize the polymerization reaction system and prevent side reactions. The polymerization stabilizer contributes to stabilizing the polymerization reaction system and suppresses undesirable side reactions. One indicator of side reactions is the production of thiophenol. The production of thiophenol can be suppressed by adding a polymerization stabilizer. Specific examples of polymerization stabilizers include compounds such as alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, and alkaline earth metal carbonates. Among these, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide are preferred. The above-mentioned alkali metal carboxylates also act as polymerization stabilizers, and are therefore included as polymerization stabilizers. Furthermore, when using an alkali metal hydrosulfide as a sulfidating agent, it is particularly preferable to use an alkali metal hydroxide at the same time. Oxides can also serve as polymerization stabilizers.

These polymerization stabilizers can be used alone or in combination of two or more. The polymerization stabilizer is generally used in an amount of 0.02 mol to 0.20 mol, preferably 0.03 mol to 0.10 mol, more preferably 0.04 mol to 0.00 mol, per 1.00 mol of the charged sulfidating agent. It is preferable to use it in a proportion of 0.9 mol. If this proportion is too small, the stabilizing effect will be insufficient, and if it is too large, it will be economically disadvantageous, and the polymer yield will tend to decrease.

The timing of adding the polymerization stabilizer is not particularly specified, and it may be added at any time during the pre-process, at the start of polymerization, or during the polymerization process, which will be described later.Also, it may be added in multiple parts, but It is more preferable to add it simultaneously at the start of the process or at the start of polymerization because it is easy.

Next, a preferred method for producing PAS of the present invention will be specifically explained in order, including a pre-process, a polymerization process, a recovery process, and a post-treatment process, but the process is not limited to this method, of course.

[pre-process]
When producing the PAS of the present invention, the sulfidating agent is used in the form of a hydrate, but before adding the dihalogenated aromatic compound and the branching/crosslinking agent, a mixture containing the organic polar solvent and the sulfidating agent is prepared. It is preferable to raise the temperature of the water and remove excess water from the system.

Furthermore, as mentioned above, a sulfidating agent prepared from an alkali metal hydrosulfide and an alkali metal hydroxide in situ in the reaction system or in a tank different from the polymerization tank may also be used. I can do it. Although there are no particular limitations on this method, it is preferable to add an alkali metal hydrosulfide and an alkali metal hydroxide to an organic polar solvent under an inert gas atmosphere at a temperature ranging from room temperature to 150°C, preferably from room temperature to 100°C. In addition, there is a method in which the temperature is raised to at least 150°C or higher, preferably 180°C to 260°C, under normal pressure or reduced pressure, and water is distilled off. A polymerization aid may be added at this stage. These raw materials may be added in any order or at the same time. Further, in order to promote distillation of water, toluene or the like may be added to carry out the reaction.

The amount of water in the system at the end of the previous step, that is, before the polymerization step, is preferably 0.01 mol to 1.00 mol per 1.00 mol of the charged sulfidating agent. Here, the amount of water within the system is the amount obtained by subtracting the amount of water removed from the polymerization system from the amount of water charged into the polymerization system. Further, the water to be charged may be in any form such as water, an aqueous solution, or crystal water.

[Polymerization process]
When producing the PAS of the present invention, it is preferable to perform a polymerization step in which the reactant prepared in the previous step is contacted with a dihalogenated aromatic compound and a branching/crosslinking agent in an organic polar solvent to undergo a polymerization reaction.

In the polymerization step, 0.06 mol or more and 0.29 mol or less of an alkali metal carboxylate are present with respect to 1.00 mol of the sulfidating agent, and a dihalogenated aromatic compound is present with respect to 1.00 mol of the sulfidating agent. It is preferable that 0.99 mol or more and 1.03 mol or less of the trihalogenated aromatic compound be present, and 0.10 mol% or more and 1.00 mol% or less of the trihalogenated aromatic compound (Step 1).

Here, the alkali metal carboxylate plays a role as a polymerization aid as mentioned above, and if the alkali metal carboxylate is present in an amount of 0.06 mol or more, the molecular weight of the resulting PAS increases. preferable. More preferably, it is 0.10 mol or more, and still more preferably 0.15 mol or more. Further, the alkali metal carboxylate is preferably present in an amount of 0.29 mol or less, more preferably 0.27 mol or less, and even more preferably 0.25 mol or less. Exceeding the above-mentioned preferred range is not preferred because the burden of wastewater treatment increases. Further, as described above, the alkali metal carboxylate may be added in the previous step.

Further, in the polymerization step, it is preferable that the trihalogenated aromatic compound be present in an amount of 0.10 mol % or more and 1.00 mol % or less with respect to 1.00 mol of the sulfidating agent.

Here, the trihalogenated aromatic compound serves as a branching/crosslinking agent as described above. From the viewpoint of increasing the molecular weight of PAS, the amount of the trihalogenated aromatic compound is preferably 0.10 mol% or more, more preferably 0.20 mol% or more, based on 1.00 mol of the sulfidating agent. It is preferably 0.30 mol% or more, and more preferably 0.30 mol% or more. On the other hand, from the viewpoint of preventing gelation of the polymer due to increased branching and crosslinking, the amount of the trihalogenated aromatic compound should be 1.00 mol % or less with respect to 1.00 mol of the sulfidating agent. is preferable, 0.80 mol% or less is more preferable, 0.60 mol% or less is even more preferable, and even more preferably 0.50 mol% or less.

When starting the polymerization process, the organic polar solvent, the sulfidating agent, the dihalogenated aromatic compound, and the branched aromatic compound are mixed in a temperature range of 25°C to 240°C, preferably 100°C to 230°C, preferably under an inert gas atmosphere.・Mix the crosslinking agent. A polymerization aid may be added at this stage. These raw materials may be added in any order or at the same time.

The temperature of this mixture is usually raised to a range of 200°C or more and 280°C or less. Although there is no particular restriction on the heating rate, a rate of 0.01°C/min to 5°C/min is usually selected, and a range of 0.1°C/min to 3°C/min is more preferable. As long as the heating rate is within the above-mentioned range, it does not necessarily have to be a constant rate, there may be a constant temperature section, or there is no problem even if the temperature is raised in multiple stages, as long as it does not impair the essence of the present invention. There may be a section where the temperature rise rate is temporarily negative.

Generally, the temperature is finally raised to 250° C. to 280° C. or less, and the reaction is carried out at that temperature for usually 0.25 hours to 50 hours, preferably 0.5 hours to 20 hours.

Before reaching the final temperature, for example, a method of reacting at 200° C. to 250° C. for a certain period of time and then raising the temperature to 250° C. to 280° C. or lower is effective in obtaining a higher molecular weight. At this time, the reaction time at 200° C. to 250° C. is usually selected in the range of 0.25 hours to 20 hours, preferably in the range of 0.25 hours to 10 hours. Furthermore, after reacting at 200°C to 250°C for a certain period of time, the conversion rate of the halogenated aromatic compound in the system is 60% or more, preferably 70% or more when the temperature is raised to 250°C to 280°C or less. % or more, more preferably 80% or more, still more preferably 90% or more. Note that the conversion rate of the halogenated aromatic compound (herein abbreviated as HA) is a value calculated using the following formula. The residual amount of HA can usually be determined by gas chromatography.
(A) When the halogenated aromatic compound is added in excess molar ratio to the alkali metal sulfide Conversion rate = [HA charged amount (mol) - HA remaining amount (mol)] / [HA charged amount (mol) - Excess amount of HA (mol)]
(B) Cases other than the above (A) Conversion rate = [HA charged amount (mol) - HA remaining amount (mol)] / [HA charged amount (mol)]

In the present invention, the polymerization time in the polymerization step is usually preferably 60 minutes or more, more preferably 120 minutes or more, from the viewpoint of increasing the molecular weight of PAS. On the other hand, from the viewpoint of productivity, the upper limit of the polymerization time is preferably 240 minutes or less, more preferably 210 minutes or less, and even more preferably 180 minutes or less. Note that the polymerization time here refers to the temperature raising/lowering time within a temperature range of 200°C or higher and 280°C or lower after charging the sulfidating agent and halogenated aromatic compound until discharging the polymerization reaction product from the reaction vessel. This is the time including.

In the polymerization step, water is preferably present in the reaction vessel in an amount of 0.50 mol or more per 1.00 mol of the sulfidating agent. In the sense of obtaining a higher molecular weight, it is more preferably 0.60 mol or more, and even more preferably 0.70 mol or more. When using water as a polymerization aid, the upper limit for water per 1.00 mol of sulfidating agent is is preferably present in an amount of 1.50 mol or less, more preferably 1.25 mol or less, and even more preferably 1.00 mol or less. The amount of water in the polymerization process refers to the amount of water within the temperature range of 250°C to 280°C in the polymerization process. This is the amount minus the amount of water removed.

As a method for making water present in the reaction vessel in an amount of 0.50 mol or more and 1.50 mol or less per 1.00 mol of the sulfidating agent, water may be added to the reaction vessel, or water may be added to the reaction vessel once. The water may be removed by opening the part. It is also possible to combine these. From the viewpoint of safety and convenience, it is preferable to add water.

[Collection process]
When producing the PAS of the present invention, solid matter is recovered from the polymerization reaction product containing the polymer, solvent, etc. after completion of polymerization. The solid matter referred to here includes not only PAS but also water-soluble substances such as by-product salts and unreacted sulfidating agents. As for the recovery method, any known method may be employed.

For example, a method may be used in which after the polymerization reaction is completed, the particulate polymer is recovered by slow cooling. There is no particular limit to the slow cooling rate at this time, but it is usually about 0.1°C/min to 3°C/min. It is not necessary to perform slow cooling at the same speed throughout the slow cooling process; slow cooling is performed at a rate of 0.1°C/min to 1°C/min until the polymer particles crystallize and precipitate, and then at a speed of 1°C/min or more. method etc. may be adopted.

Also, one of the preferable methods is to perform the above-mentioned recovery under quenching conditions. Among these recovery methods, a preferred method is the flash method. In the flash method, the polymerization reaction product is flashed from a high temperature and high pressure state (usually 250°C or higher, 8kg/cm2 ^or higher) into a normal pressure, reduced pressure, or pressurized atmosphere, and the solvent is distilled off and the polymer is simultaneously removed. This is a method of recovering the waste in powder form. The term "flash" as used herein means that the polymerization reaction product is ejected from a nozzle. Specific examples of the flashing atmosphere include nitrogen or water vapor at normal pressure, and the temperature is usually selected from a range of 150°C to 250°C.

In the production of PAS of the present invention, either a method of slowly cooling and recovering particulate PAS or a method of rapidly cooling and recovering powdered PAS may be used. In the method of A preferred method is to flash the PAS from a high temperature and high pressure state into an atmosphere of normal pressure, reduced pressure, or pressurization, and then rapidly cool it while distilling off the solvent to recover powdered PAS (Step 2).

[Post-processing process]
PAS may be produced through the above polymerization and recovery steps and then subjected to hot water treatment, acid treatment, washing with an organic solvent, and alkali metal or alkaline earth metal treatment.

In the present invention, the solid material obtained through the above-mentioned recovery step contains not only PAS but also water-soluble substances such as by-product salts and unreacted sulfidizing agents, so it is preferable to wash it with hot water. When performing hot water treatment, the procedure is as follows. When treating PAS with hot water, the temperature of the hot water is preferably 100°C or higher, more preferably 120°C or higher, even more preferably 150°C or higher, particularly preferably 170°C or higher. If the temperature is less than 100°C, the effect of the preferable chemical modification of PAS will be small, which is not preferable. The water used is preferably distilled water or ion-exchanged water in order to achieve the desired effect of chemical modification of PAS by hot water washing. There are no particular restrictions on the operation of hot water treatment. This is carried out by adding a predetermined amount of PAS to a predetermined amount of water, heating and stirring it in a pressure vessel, or continuously subjecting it to hot water treatment. As for the ratio of PAS to water, it is preferable to have a large amount of water, but usually a bath ratio of 200 g or less of PAS to 1 liter of water (the weight of the cleaning liquid relative to the weight of dry PAS) is selected.

In the present invention, it is preferable to acid-treat PAS from the viewpoint of obtaining PAS having a high functional group content and a high cooling-down crystallization temperature. The case where acid treatment is performed is as follows. The acid used for the acid treatment of PAS is not particularly limited as long as it does not have the effect of decomposing PAS, and examples include acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, silicic acid, carbonic acid, and propylic acid. Among them, acetic acid and hydrochloric acid are more preferably used. On the other hand, substances that decompose and degrade PAS, such as nitric acid, are not preferred.

Further, in order to avoid undesirable decomposition of the terminal reactive functional group, it is desirable that the treatment atmosphere be an inert atmosphere. Further, in order to remove residual components, it is preferable to wash the PAS after this acid treatment several times with warm water.

A method for acid treatment includes, for example, a method of immersing PAS in an acid or an aqueous solution of an acid, and it is also possible to stir or heat if necessary. For example, when using acetic acid, a sufficient effect can be obtained by immersing the PAS powder in an acetic acid aqueous solution having a pH of 3 or more and less than 7 heated to 80° C. to 200° C. and stirring for 30 minutes. The pH after the treatment may be higher than the pH of the acetic acid aqueous solution used, for example, about pH 4 to 8. In order to remove residual acids or salts from the acid-treated PAS, it is preferable to wash it several times with water or hot water. The water used for washing is preferably distilled water or ion-exchanged water so as not to impair the effect of chemical modification of PAS by acid treatment. PAS subjected to acid treatment is preferable because it has excellent reactivity during molding and processing and also has a high crystallization temperature.

When drying PAS after acid treatment, if the drying temperature is too high, the PAS particles will fuse together and the specific surface area will become small, which tends to make it impossible to achieve a sufficient cleaning effect in the organic solvent cleaning described below. Therefore, the upper limit is preferably 170°C or less, more preferably 150°C or less. In addition, from the viewpoint of drying efficiency, the lower limit of the drying temperature is preferably 70°C or higher, more preferably 100°C or higher, and even more preferably 120°C or higher. When the drying temperature of PAS is in the above preferable range, the specific surface area of the PAS after drying becomes large, and the oligomers in the PAS tend to be sufficiently washed and removed in the organic solvent washing described below. Additionally, it tends to be able to dry efficiently in a short period of time. In addition, the atmosphere during drying is desirably non-oxidizing conditions, preferably an inert gas atmosphere such as nitrogen, helium, or argon, and in particular, a nitrogen atmosphere from the viewpoint of economy and ease of handling. Lower is more preferable. Drying PAS in such an atmosphere tends to prevent modification of PAS due to oxidation.

Moreover, although there is no particular restriction on the drying time, a lower limit of 0.5 hours or more can be exemplified, and 1 hour or more is preferable. Further, the upper limit is preferably 50 hours or less, more preferably 20 hours or less, and even more preferably 10 hours or less. When the drying time of PAS is within the above preferable range, PAS can be efficiently produced industrially.

Here, there are no particular restrictions on the dryer used for drying, and general vacuum dryers and hot air dryers can be used, as well as heating devices with rotary or stirring blades, fluidized bed dryers, etc. It is also possible. In addition, from the viewpoint of efficiently and uniformly drying PAS, it is preferable to use a rotating heating device or a heating device equipped with stirring blades.

In the present invention, it is preferable to wash PAS with an organic solvent in order to keep the amount of oligomer in the obtained PAS within a preferable range. When washing with an organic solvent, the procedure is as follows. The organic solvent used for cleaning PAS is not particularly limited as long as it does not have the effect of decomposing PAS. For example, nitrogen-containing polar solvents such as N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, 1,3-dimethylimidazolidinone, hexamethylphosphorusamide, and piperazinone; sulfoxides such as dimethylsulfoxide, dimethylsulfone, and sulfolane; Sulfonic solvents, ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, acetophenone, ether solvents such as dimethyl ether, dipropyl ether, dioxane, tetrahydrofuran, chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchloroethylene, monochloroethane , halogenated solvents such as dichloroethane, tetrachloroethane, perchloroethane, and chlorobenzene, alcohols and phenols such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, and polypropylene glycol. Examples of organic solvents used for cleaning PAS include organic solvents and aromatic hydrocarbon solvents such as benzene, toluene, and xylene. Among these organic solvents, use of N-methyl-2-pyrrolidone, acetone, dimethylformamide, chloroform, and the like is particularly preferred. Further, these organic solvents may be used alone or in combination of two or more.

As a method for washing with an organic solvent, for example, there is a method of immersing the PAS in an organic solvent, and it is also possible to stir or heat as appropriate, if necessary. There are no particular restrictions on the cleaning temperature when cleaning PAS with an organic solvent, and any temperature from room temperature to about 300°C can be selected. Although the higher the cleaning temperature, the higher the cleaning efficiency tends to be, usually a cleaning temperature of room temperature to 150° C. can be sufficiently effective. It is also possible to wash under pressure in a pressure vessel at a temperature above the boiling point of the organic solvent. Furthermore, there is no particular restriction on the cleaning time. Although it depends on the cleaning conditions, in the case of batch cleaning, sufficient effects can usually be obtained by cleaning for 5 minutes or more. It is also possible to wash continuously. In the post-treatment step, it is preferable to perform acid treatment, hot water treatment, or washing with an organic solvent, and it is preferable to use two or more types of treatments in combination from the viewpoint of removing impurities.

The moisture content of PAS before washing with an organic solvent is preferably 30% by weight or less. Since water is a poor solvent for the chloroform extract components in PAS, reducing the water content of PAS tends to make it easier to reduce the chloroform extract components when PAS is washed with an organic solvent. Note that if the organic solvent used for cleaning PAS is a water-insoluble organic solvent such as chloroform or toluene, stable cleaning effects tend to be obtained regardless of the water content of PAS. Although it is not necessary to reduce the water content of PAS to 30% by weight or less, considering that N-methyl-2-pyrrolidone, which is particularly preferably used from the viewpoint of availability, is a water-soluble organic solvent, A more preferable method is to reduce the amount. Here, the lower limit of the water content of PAS before washing with an organic solvent is preferably as small as possible in order to enhance the washing effect, and 0% by weight, where no water is contained in PAS, is most preferable. On the other hand, the upper limit is more preferably 10% by weight or less, further preferably 5% by weight or less, and even more preferably 1% by weight or less. When the water content of PAS before washing with an organic solvent is in the above preferable range, when a water-soluble organic solvent is used for washing PAS, the amount of chloroform extractable components in PAS tends to be more easily reduced. Note that as a method for reducing the water content to 30% by weight or less, as described above, a method of drying the PAS after acid treatment can be mentioned.

Here, the water content measurement of PAS in the present invention is carried out by the Karl Fischer method in accordance with Japanese Industrial Standard JIS K 7251.

Methods for treating alkali metals and alkaline earth metals include adding an alkali metal salt or alkaline earth metal salt before, during, or after the preceding step, before the polymerization step, during the polymerization step, or during the polymerization step. Examples include a method in which an alkali metal salt or an alkaline earth metal salt is added later into the polymerization reactor, or a method in which an alkali metal salt or an alkaline earth metal salt is added at the beginning, middle, or end of the washing step. Among them, the easiest method is to remove residual oligomers and salts by washing with an organic solvent or hot water or hot water, and then add an alkali metal salt or alkaline earth metal salt. The alkali metals and alkaline earth metals are preferably introduced into the PAS in the form of alkali metal ions and alkaline earth metal ions such as acetates, hydroxides, and carbonates. Further, it is preferable to remove excess alkali metal salts and alkaline earth metal salts by washing with hot water or the like. The concentration of alkali metal ions and alkaline earth metal ions upon introduction of the alkali metal and alkaline earth metal is preferably 0.001 mmol or more, more preferably 0.01 mmol or more, per 1 g of PAS. The temperature is preferably 50°C or higher, more preferably 75°C or higher, and particularly preferably 90°C or higher. Although there is no particular upper limit temperature, from the viewpoint of operability, 280° C. or lower is usually preferable. The bath ratio (the weight of cleaning liquid to the weight of dry PAS) is preferably 0.5 or more, more preferably 3 or more, and even more preferably 5 or more.

In the present invention, as a post-treatment step, the solid material containing polyarylene sulfide is washed with water and then treated with acid (step 3), and following step 3, the polyarylene sulfide is washed with an organic solvent. It is preferable to perform the step (Step 4). Thereby, oligomer components can be efficiently removed.

[Heat treatment process]
In addition, the PAS in the present invention can also be used after the polymerization is completed by heat treatment by heating in an oxygen atmosphere or by heating with the addition of a crosslinking agent such as a peroxide to increase the molecular weight.

When dry heat treatment is performed for the purpose of increasing the molecular weight by thermal oxidative crosslinking, the temperature is preferably in the range of 160°C to 260°C, more preferably in the range of 170°C to 250°C. Further, the oxygen concentration is preferably 5% by volume or more, more preferably 8% by volume or more. There is no particular upper limit to the oxygen concentration, but the upper limit is about 50% by volume. The treatment time is preferably 0.5 hours to 100 hours, more preferably 1 hour to 50 hours, and even more preferably 2 hours to 25 hours. The heat treatment device may be a conventional hot air dryer or a rotating type or heating device equipped with stirring blades. For efficient and more uniform treatment, it is preferable to use a rotating heating device or a heating device equipped with stirring blades.

It is also possible to perform dry heat treatment for the purpose of increasing viscosity and removing volatile matter while suppressing excessive thermal oxidative crosslinking. The temperature is preferably in the range of 130°C to 250°C, more preferably in the range of 160°C to 250°C. Further, the oxygen concentration in this case is desirably less than 5% by volume, more preferably 2% by volume or less. The lower limit of the treatment time can be exemplified as 0.1 hour or more, and from the viewpoint of stabilizing the conditions within the heat treatment apparatus and stably controlling the increase in molecular weight due to the heat treatment, the lower limit of the treatment time is preferably 0.25 hours or more, and 0.5 hours. The time is more preferable, and the time is even more preferable to be 1 hour or more. An example of the upper limit of the processing time is 50 hours or less, and from the viewpoint of productivity, 20 hours or less is preferable, and 10 hours or less is more preferable. The heat treatment device may be a conventional hot air dryer or a rotating or stirring blade-equipped heating device. For efficient and more uniform treatment, it is more preferable to use a rotating heating device or a heating device equipped with stirring blades.

[Characteristics of PAS]
The PAS of the present invention has a chloroform extractable content of 0.5% by weight or more and 2.0% by weight or less, and has a melt flow rate measured at 315°C and a load of 5000g in accordance with ASTM D 1238-70. is 5 g/10 minutes or more and 300 g/10 minutes or less, and the cooling crystallization temperature (Tmc) measured with a differential scanning calorimeter (DSC) at a cooling rate of 20° C./min is 190° C. or more and 230° C. or less, and It is characterized by having a carboxyl group content of 35 μmol/g or more and 100 μmol/g or less.

The chloroform extract components in the present invention mainly include oligomer components contained in PAS. Note that the oligomer component referred to herein is a component consisting of a cyclic PAS and a linear PAS oligomer, and there is no particular restriction on the ratio of these components. Furthermore, these components are volatile components that cause mold stains during injection molding. If the amount of the chloroform extracted component exceeds 2.0% by weight, the problem of mold staining occurs when molding PAS. From the viewpoint of reducing mold staining, the upper limit of the amount of chloroform extracted components is preferably 1.8% by weight or less, more preferably 1.6% by weight or less, and even more preferably 1.4% by weight or less. Note that when the lower limit of the amount of chloroform extracted components in PAS is less than 0.5% by weight, the amount of PAS oligomers having functional groups decreases, and the functional group content of PAS decreases significantly. Note that the PAS oligomer referred to here is removed by washing with an organic polar solvent. The amount of components extracted with chloroform is calculated by weighing 10 g of the polymer, performing Soxhlet extraction with 100 g of chloroform for 3 hours, measuring the weight of the components obtained after distilling off the chloroform from this extract, and calculating the ratio to the weight of the charged polymer. (Measurement method 1), 1 g of polymer was weighed, stirred in 20 g of chloroform for 1 hour at room temperature, solid-liquid separated, chloroform was distilled off from the filtrate, and then vacuum-dried at 130°C to calculate the weight of the resulting component. There is a method (measurement method 2) in which the amount is measured and calculated as a proportion to the weight of the charged polymer. In the present invention, the amount of chloroform extracted components is determined by the value calculated by measurement method 2.

If the melt flow rate (hereinafter abbreviated as MFR) of PAS exceeds 300 g/10 minutes, there will be problems with mechanical strength and toughness during molding. From the viewpoint of excellent mechanical strength and toughness during molding, the upper limit of MFR is more preferably 200 or less, and even more preferably 150 or less. On the other hand, if the lower limit of MFR is less than 5 g/10 minutes, the melt fluidity will be low, and PAS will not be able to enter the mold during injection molding, resulting in a tendency that a molded product will not be obtained. From the viewpoint of excellent melt fluidity, the lower limit of MFR is more preferably 10 g/10 minutes or more, even more preferably 30 g/10 minutes or more, and even more preferably 50 g/10 minutes or more. MFR is a value measured at a temperature of 315.5° C. and a load of 5000 g according to ASTM D 1238-70.

If the cooling crystallization temperature (Tmc) of PAS measured at a cooling rate of 20° C./min is lower than 190° C., the crystallization rate will be slow and the time cycleability during molding will be reduced, which is not preferable. From the viewpoint of productivity, the temperature is preferably 200°C or higher, more preferably 210°C or higher, and even more preferably 220°C or higher. On the other hand, when Tmc exceeds 230°C, there is a problem that the solidification rate increases and the degree of crystallinity decreases. In general, as the number of branched/crosslinked structures increases, the cooling crystallization temperature tends to decrease. Therefore, as the amount of the polyhalogenated aromatic compound having three or more halogens increases, the Tmc decreases. Further, in the PAS manufacturing process, the cooling crystallization temperature is improved by acid treatment in the post-treatment process. Although the reason for this is not clear, it is presumed that the cooling crystallization temperature is lowered due to the influence of the metal species at the end of the polymer.

If the carboxyl group content of PAS is less than 35 μmol/, sufficient reactivity between PAS and a foreign material cannot be obtained, which is not preferable. From the viewpoint of excellent reactivity with different materials, the lower limit of the carboxyl group content is preferably 40 μmol/g or more, more preferably 45 μmol/g or more, and even more preferably 50 μmol/g or more. On the other hand, if the carboxyl group content exceeds 100 μmol/g, the amount of volatile components during molding tends to increase, and voids tend to form in the molded product, which is not preferable. The amount of these volatile components is preferably 70 μmol/g or less from the viewpoint of easily reducing voids. In the present invention, by using a trihalogenated aromatic compound as a branching/crosslinking agent, the carboxyl group content falls within the above-mentioned preferred range. The reason for this is not clear, but it is presumed to be due to the high reactivity of the trihalogenated aromatic compound. Further, in general, the carboxyl group content when a trihalogenated aromatic compound is not used is lower than when a trihalogenated aromatic compound is used. The carboxyl group content of PAS here is determined by measuring the amorphous film of PAS resin using FT-IR (IR-810 model infrared spectrophotometer manufactured by JASCO Corporation). It can be estimated by comparing the absorption near 1,730 cm ^-1 derived from the carboxyl group with the absorption near 900 cm ^-1 .

The lower limit of the dispersity expressed by weight average molecular weight Mw/number average molecular weight Mn (hereinafter abbreviated as Mw/Mn) of the PAS of the present invention is preferably 5.5 or more, and preferably 6.0 or more. is more preferable, more preferably 6.5 or more, even more preferably 7.0 or more. The larger Mw/Mn is, the higher the non-Newtonian property is, so the molding processability during extrusion molding and blow molding is excellent. On the other hand, there is no particular restriction on the upper limit of Mw/Mn, but it is usually 15.0 or less. In the present invention, by using a trihalogenated aromatic compound as a branching/crosslinking agent, Mw/Mn can be set within the above preferable range. Furthermore, as the amount of the trihalogenated aromatic compound increases, Mw/Mn increases. Generally, Mw/Mn is 5.0 or less when no branching/crosslinking agent is used. Note that Mw/Mn here is a value measured using gel permeation chromatography (GPC) using 1-chloronaphthalene as an eluent at a column temperature of 210° C. and converted to a polystyrene standard.

The lower limit of the ash content of the PAS of the present invention is 0 or more, but an example of a normal range is 0.01% by weight or more. The upper limit of the ash content is preferably 0.20% by weight or less, and 0.15% by weight or less, since a large amount of inorganic substances in PAS may cause a decrease in physical properties or a decrease in cooling crystallization temperature. The content is more preferably 0.10% by weight or less, even more preferably 0.07% by weight or less, and even more preferably 0.05% by weight or less. The ash content can be adjusted mainly by post-treatments such as hot water treatment, acid treatment, and washing with organic solvents.

[Applications of PAS]
The PAS of the present invention has excellent heat resistance, chemical resistance, flame retardance, electrical properties, and mechanical properties, and can be used not only for injection molding, injection compression molding, and blow molding, but also for sheets, films, and fibers by extrusion molding. It can also be formed into extruded products such as pipes.

Further, the PAS of the present invention can be used, for example, in sensors, LED lamps, connectors, sockets, resistors, relay cases, switches, coil bobbins, capacitors, variable capacitor cases, optical pickups, resonators, various terminal boards, transformers, plugs, etc. Electrical and electronic components such as printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, semiconductors, liquid crystals, FDD carriages, FDD chassis, motor brush holders, parabolic antennas, computer-related parts, etc. ;VTR parts, TV parts, irons, hair dryers, rice cooker parts, microwave oven parts, audio parts, audio equipment parts such as audio/laser discs (registered trademark)/compact discs, lighting parts, refrigerator parts, air conditioner parts, type Household and office appliance parts, such as lighter parts and word processor parts; office computer-related parts, telephone-related parts, facsimile-related parts, copying machine-related parts, cleaning jigs, motor parts, lighters, typewriters, etc. Typical machine-related parts: Optical instruments such as microscopes, binoculars, cameras, and watches, precision machine-related parts; water faucet tops, mixer faucets, pump parts, pipe joints, water volume control valves, relief valves, hot water temperature Water-related parts such as sensors, water flow sensors, and water meter housings; various valves such as valve alternator terminals, alternator connectors, IC regulators, potentiometer bases for light dialers, exhaust gas valves, and various pipes for fuel-related, exhaust, and intake systems. , air intake nozzle snorkel, intake manifold, fuel pump, engine cooling water joint, carburetor main body, carburetor spacer, exhaust gas sensor, cooling water sensor, oil temperature sensor, throttle position sensor, crankshaft position sensor, air flow meter, brake Pad wear sensor, air conditioner thermostat base, heating hot air flow control valve, brush holder for radiator motor, water pump impeller, turbine vane, wiper motor related parts, dust distributor, starter switch, starter relay, transmission wiring harness, window Washer nozzles, air conditioner panel switch boards, fuel-related electromagnetic valve coils, fuse connectors, horn terminals, electrical component insulation boards, step motor rotors, lamp sockets, lamp reflectors, lamp housings, brake pistons, solenoid bobbins, engine oil filters, Automotive and vehicle-related parts such as ignition system cases, vehicle speed sensors, cable liners, engine control unit cases, engine driver unit cases, condenser cases, motor insulation materials, hybrid car control system parts cases, various seats, front bodies, and under bodies. , various pillars, various members, various frames, various beams, various supports, various rails, various automobile body parts such as hinges, aircraft engine peripheral parts such as fan blades, landing gear pods, winglets, spoilers, edges, rudders, elevators. Examples include aircraft-related parts such as , falling, ribs, and various other uses.

The PAS obtained by the production method of the present invention can also be used with a filler added thereto to the extent that the effects of the present invention are not impaired. As a specific example of such a filler, either an organic filler or an inorganic filler may be used, and either a fibrous filler or a non-fibrous filler may be used. The shape of the fibrous filler is not particularly limited, and may include fiber bundles such as chopped strands and rovings, woven fabrics such as plain weave and twill weave, knitted fabrics, nonwoven fabrics, fiber papers, and UD materials (unidirectional). The fibrous filler sheet can be appropriately selected as needed from among the fibrous filler sheets such as fibrous filler sheets such as fibrous filler materials. The type of fibrous filler is not particularly limited, and examples include carbon fiber, metal fiber, organic fiber, and inorganic fiber. Two or more types of these may be used.

As a method for producing a PAS film using PAS of the present invention, a known melt film forming method can be adopted. For example, after melting PAS in a single-screw or twin-screw extruder, extrusion from a film die, The film is produced by cooling on a cooling drum to create a film, or by a biaxial stretching method in which the film thus created is stretched vertically and horizontally using a roller-type longitudinal stretching device and a horizontal stretching device called a tenter. However, it is not particularly limited to this.

The PAS film obtained in this way has excellent mechanical properties, electrical properties, and heat resistance, and is suitable for use in various applications such as dielectric film for film capacitors and chip capacitors, and release film. can do.

As a method for producing PAS fibers using PAS of the present invention, a known melt spinning method can be applied. For example, PAS chips as a raw material are kneaded while being fed to a single-screw or twin-screw extruder, It is possible to adopt a method of extruding the polymer through a spinneret through a polymer flow line exchanger installed at the tip of the extruder, a filtration layer, etc., cooling it, stretching it, heat setting it, etc., but it is not particularly limited thereto. isn't it.

The PAS monofilaments or short fibers thus obtained can be suitably used in various applications such as paper dryer campuses, net conveyors, and bag filters.

Hereinafter, the method of the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited only to these Examples.

[Measurement of the amount of chloroform extracted components (measurement method 1)]
The amount of chloroform extracted components in PAS is determined by weighing 10 g of polymer, performing Soxhlet extraction with 100 g of chloroform for 3 hours, measuring the weight of the components obtained after distilling off chloroform from this extract, and calculating the amount as a proportion to the weight of the charged polymer. Calculated.

[Measurement of chloroform extracted component amount (measurement method 2)]
The amount of chloroform extracted components in PAS was obtained by weighing 1 g of polymer, stirring it in 20 g of chloroform for 1 hour at room temperature, separating solid and liquid, distilling off chloroform from the filtrate, and drying it under vacuum at 130°C. The weight of the components was measured and calculated as a proportion to the weight of the charged polymer.

[Melt flow rate (MFR)]
Measurement was performed at a temperature of 315.5° C. and a load of 5000 g in accordance with ASTM D 1238-70. Using a Toyo Seiki melt indexer (length 8.00 mm, hole diameter 2.095 mm orifice, sample amount 7 g, preheating time from sample preparation to start of measurement 5 minutes, load 5 kg) at 315.5 ° C. Measurements were taken.

[Dispersity (Mw/Mn) measurement]
The dispersity (Mw/Mn) expressed as weight average molecular weight/number average molecular weight was calculated in terms of polystyrene by gel permeation chromatography (GPC), which is a type of size exclusion chromatography (SEC). The GPC measurement conditions are shown below.
Equipment: Senshu Science SSC-7110
Column name: Shodex UT806M x 2
Eluent: 1-chloronaphthalene Detector: Differential refractive index detector Column temperature: 210°C
Pre constant temperature bath temperature: 250℃
Pump constant temperature bath temperature: 50℃
Detector temperature: 210℃
Flow rate: 1.0mL/min
Sample injection volume: 300 μL.

[Measurement of cooling crystallization temperature]
Using a differential scanning calorimeter DSCQ200 manufactured by TA, the temperature was raised from 50°C to 340°C under a nitrogen flow at a temperature increase rate of 20°C/min, held for 1 minute, and then heated at a cooling rate of 20°C/min. The temperature was lowered from 340°C to 100°C, and the cooling crystallization temperature (Tmc) of PAS was measured.

[Creation of amorphous film]
The conditions for producing the amorphous film are as follows. PAS and a spacer (about 0.3 mm aluminum plate) were sandwiched between polyimide films. The polyimide film was placed between press molds heated to a temperature higher than the melting point of PAS, and pressurized for 1 minute. After pressurizing for 1 minute to allow PAS to remain, the entire polyimide film was taken out and immersed in prepared water for rapid cooling to obtain an amorphous film.

[Carboxyl group content]
The carboxyl group content of PAS was measured by FT-IR (IR-810 model infrared spectrophotometer manufactured by JASCO Corporation) of the amorphous film of PAS, and the absorption at around 1,900 cm ^-1 derived from the benzene ring was determined. The estimation was made by comparing the absorption near 1,730 cm ⁻¹ derived from the carboxyl group.

[Ash content]
5.0 g of PAS was weighed into a crucible and fired at 550° C. for 6 hours in a TMF-5 electric furnace manufactured by Thomas Scientific Instruments Co., Ltd. After that, it was taken out into a desiccator containing a desiccant and cooled, and then the weight of the recovered residue was weighed, and the ash content was calculated using the ratio of the weight of the residue to the weight of PAS before firing as a percentage.

[Example 1]
In an autoclave equipped with a stirrer and a bottom plug valve, 118.03 g (1.00 mol) of 47.5% sodium bisulfide, 42.26 g (1.01 mol) of 96% sodium hydroxide, and N-methyl-2-pyrrolidone. (NMP) 208.17g (2.10 mol), sodium acetate 20.10g (0.25 mol) and 78.57g of ion-exchanged water were added, and the mixture was gradually heated to 225°C over about 3 hours while passing nitrogen under normal pressure. When 140.57 g of water and 4.00 g of NMP were distilled out, heating was completed and cooling was started. At this point, the amount of hydrogen sulfide scattered was 0.02 mol, so the amount of sulfidating agent in the system after this step was 0.98 mol.

Thereafter, it was cooled to 200°C, and 144.50 g (0.98 mol) of p-dichlorobenzene (p-DCB) and 0.60 g (3.5 mol) of 1,2,4-trichlorobenzene (1,2,4-TCB) were added. After adding 3 mmol, 0.34 mol%/sulfidating agent) and 79.30 g (0.80 mol) of NMP, the reaction vessel was sealed under nitrogen gas and heated at 200 °C at a rate of 0.6°C/min with stirring. After raising the temperature from 0.degree. C. to 240.degree. C., the temperature was raised from 240.degree. C. to 276.degree. C. at a rate of 0.8.degree. C./min.

After reacting at 276°C for 123 minutes, the bottom valve of the autoclave was opened, and while pressurizing with nitrogen, the contents were flushed into a container equipped with a stirrer over 15 minutes, and stirred at 250°C for a while to remove most of the NMP. was removed.

The obtained recovered material and 1.10 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. Next, 1.10 liters of ion-exchanged water heated to 70°C was poured into a glass filter and filtered with suction to obtain a cake.

The obtained cake and 1.30 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, and acetic acid was added. After purging the inside of the autoclave with nitrogen, the temperature was raised to 192°C and held for 30 minutes. Thereafter, the autoclave was cooled and the contents were taken out. The pH of the solution after acid treatment was 4. After the contents were suction-filtered through a glass filter, 1.10 liters of ion-exchanged water at 70°C was poured thereinto and suction-filtered to obtain a cake. Dry PAS was obtained by drying the obtained cake at 120° C. under a nitrogen stream. The obtained dry PAS was placed in an autoclave equipped with a stirrer, 53.50 g of NMP was added thereto, and the mixture was stirred at 30° C. for 20 minutes, followed by suction filtration through a glass filter to obtain a cake. Dry PAS was obtained by drying the obtained wet cake at 220° C. for 3 hours under a nitrogen stream. The polymer properties of the obtained PAS were as shown in Table 1.

[Example 2]
The p-DCB was changed to 144.71 g (0.98 mol) and the 1,2,4-TCB was changed to 0.46 g (2.5 mmol, 0.26 mol%/sulfidating agent), and the reaction was performed at 276°C. Polymerization and washing were carried out in the same manner as in Example 1, except that the time was changed to 63 minutes. The polymer properties of the obtained PAS were as shown in Table 1.

[Example 3]
Same as Example 2 except that p-DCB was changed to 144.17 g (0.98 mol) and 1,2,4-TCB was changed to 0.84 g (4.6 mmol, 0.47 mol%/sulfidating agent). Polymerization and washing were performed in the same manner. The polymer properties of the obtained PAS were as shown in Table 1.

[Example 4]
Polymerization and washing were carried out in the same manner as in Example 2, except that p-DCB was changed to 143.42 g (0.98 mol). The polymer properties of the obtained PAS were as shown in Table 1.

[Example 5]
The amount of sodium acetate was changed to 15.27 g (0.19 mol), and the 1,2,4-TCB was changed to 0.533 g (2.9 mmol, 0.30 mol%/sulfidating agent). Polymerization and washing were carried out in the same manner as in Example 2 except for this. The polymer properties of the obtained PAS were as shown in Table 1.

[Example 6]
Polymerization and washing were carried out in the same manner as in Example 5, except that the reaction time at 276°C was changed to 123 minutes. The polymer properties of the obtained PAS were as shown in Table 1.

[Example 7]
Polymerization and washing were carried out in the same manner as in Example 6, except that the pH of the solution after acid treatment was 7 during the acid treatment in the post-treatment step. The polymer properties of the obtained PAS were as shown in Table 1.

[Example 8]
The PAS of Example 6 was placed in a heating device equipped with a stirrer, and heat-treated at 220° C. for 10 minutes at an oxygen concentration of 2%. In the heat treatment at an oxygen concentration of 2%, 0.18 liters/min of air and 1.78 liters/min of nitrogen were introduced into the heating device, and an oxygen concentration meter was installed in the heating device to measure the oxygen concentration. The polymer properties of the obtained PAS were as shown in Table 1. In addition, heat treatment was performed under the same conditions except that the heat treatment temperature and time were 220° C. x 30 minutes, and the MFR of the obtained PAS polymer was measured. The relationship between heat treatment time and melt viscosity is shown in Table 2.

[Example 9]
The same treatment as in Example 8 was performed except that the PAS of Example 7 was used. The polymer properties of the obtained PAS were as shown in Table 1. In addition, heat treatment was performed under the same conditions except that the heat treatment temperature and time were 220° C. x 30 minutes, and the MFR of the obtained PAS polymer was measured. The relationship between heat treatment time and melt viscosity is shown in Table 2.

[Comparative example 1]
Polymerization and washing were carried out in the same manner as in Example 1, except that washing with an organic solvent was not carried out. The polymer properties of the obtained PAS were as shown in Table 1.

[Comparative example 2]
Polymerization and washing were performed in the same manner as in Example 2, except that washing with an organic solvent was not performed. The polymer properties of the obtained PAS were as shown in Table 1.

[Comparative example 3]
Polymerization and washing were carried out in the same manner as in Example 2, except that the acid treatment was not performed. The polymer properties of the obtained PAS were as shown in Table 1.

[Comparative example 4]
Polymerization and washing were carried out in the same manner as in Example 5, except that p-DCB was changed to 14.81 g (1.01 mol) and 1,2,4-TCB was not added. The polymer properties of the obtained PAS were as shown in Table 1.

[Comparative example 5]
Without adding sodium acetate, p-DCB was changed to 14.67 g (1.00 mol) and 1,2,4-TCB was changed to 1.07 g (5.9 mmol, 0.60 mol%/sulfidating agent). Polymerization and washing were carried out in the same manner as in Example 2, except for the following. The polymer properties of the obtained PAS were as shown in Table 1.

[Comparative example 6]
Polymerization and washing were performed in the same manner as in Comparative Example 5, except that 1,2,4-TCB was changed to 2.67 g (14.7 mmol, 1.50 mol%/sulfidating agent). The polymer properties of the obtained PAS were as shown in Table 1.

[Comparative Example 7]
In an autoclave with a stirrer and a bottom stopper valve, 118.03 g (1.00 mol) of 47.5% sodium bisulfide, 43.12 g (1.04 mol) of 96% sodium hydroxide, and N-methyl-2-pyrrolidone. (NMP) 163.56g (1.65 mol), sodium acetate 27.07g (0.33 mol) and ion-exchanged water 33.30g were charged, and the mixture was gradually heated to 225°C over about 3 hours while passing nitrogen under normal pressure. Heating was completed and cooling was started when 138.67 g of water and 3.62 g of NMP were distilled out. At this point, the amount of hydrogen sulfide scattered was 0.02 mol, so the amount of sulfidating agent in the system after this step was 0.98 mol.

After that, it was cooled to 200°C, and after adding 148.38 (1.01 mol) of p-dichlorobenzene (p-DCB) and 133.83 g (1.35 mol) of NMP, the reaction vessel was sealed under nitrogen gas. The temperature was raised from 200°C to 218°C at a rate of 1.0°C/min while stirring, and then from 218°C to 270°C at a rate of 0.6°C/min. After the reaction was carried out at 270°C for 140 minutes, it was cooled to 250°C at a rate of 1.3°C/min while 18.00 g of water was introduced under pressure over 15 minutes. Thereafter, it was cooled to 200° C. at a rate of 0.4° C./min, and then rapidly cooled to near room temperature.

The contents were taken out and washed twice with 570 g of NMP, followed by suction filtration through a glass filter to obtain a cake.

The resulting cake and 1.10 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. Next, 1.10 liters of ion-exchanged water heated to 70°C was poured into a glass filter and filtered with suction to obtain a cake.

The obtained cake and 1.30 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, and acetic acid was added. After purging the inside of the autoclave with nitrogen, the temperature was raised to 192°C and held for 30 minutes. Thereafter, the autoclave was cooled and the contents were taken out. The pH of the solution after acid treatment was 4. After the contents were suction-filtered through a glass filter, 1.10 liters of ion-exchanged water at 70°C was poured thereinto and suction-filtered to obtain a cake. Dry PAS was obtained by drying the obtained cake at 120° C. under a nitrogen stream. The polymer properties of the obtained PAS were as shown in Table 1.

The results of the above example and comparative example will be compared and explained.

In Examples 1 to 7, 0.06 mol or more and 0.29 mol or less of sodium acetate, which is an alkali metal carboxylate, was present per 1.00 mol of the sulfidating agent, and 0.06 mol or more and 0.29 mol or less of the dihalogenated aromatic compound. High viscosity PAS can be obtained efficiently and in a short time by reacting a trihalogenated aromatic compound as a branching/crosslinking agent in an amount of 99 mol or more and 1.03 mol or less and 0.10 mol% or more and 1.00 mol% or less. It was done.

In Example 2, in which the polymerization time was shorter than that in Example 1, a high-viscosity PAS was also obtained. Furthermore, the comparison of Examples 2 to 4 shows that the viscosity of PAS can be adjusted by changing the amount of the trihalogenated aromatic compound, and the comparison of Examples 5 and 6 shows that the viscosity of PAS can be adjusted by changing the polymerization time. I understand that there is something.

From the results of Examples 6 and 7, the melt viscosity and viscosity change during melt retention were different when the ash content was different, and Example 6 was able to increase the viscosity of PAS with a shorter heat treatment time. . Example 7 had a relatively smaller change in melt viscosity with respect to heat treatment time, and was superior in handleability in the heat treatment process.

From the results of Examples 8 and 9, it can be seen that performing a heat treatment step is also effective for efficiently obtaining PAS with a higher viscosity in a short time.

In Comparative Example 1, PAS was not washed with an organic solvent, so the amount of chloroform extracted components in the obtained PAS was much larger than in Example 1, which was washed with an organic solvent. Similarly, in Comparative Example 2, the PAS was not washed with an organic solvent, so the amount of chloroform extracted components in the obtained PAS was much higher than in Example 2, which was washed with an organic solvent, and the MFR was also high. .

In Comparative Example 3, PAS was not treated with an acid, so the carboxyl group content of the obtained PAS was extremely low compared to Example 2, which was treated with an acid.

Since Comparative Example 4 did not use a trihalogenated aromatic compound, the MFR of the obtained PAS was higher and the degree of dispersion was lower than in Example 5, which used a trihalogenated aromatic compound. Ta.

In Comparative Example 5, since sodium acetate was not used, the MFR of the obtained PAS was extremely high compared to Examples 1 to 7.

In Comparative Example 6, since the trihalogenated aromatic compound was used in an amount exceeding 1.00 mol % with respect to 1.00 mol of the sulfidating agent, the resulting PAS gelled when heated, causing problems in processability. In addition, the cooling crystallization temperature was low.

In Comparative Example 7, since PAS was recovered by slow cooling after the polymerization reaction was completed, the polymerization time including raising and lowering the temperature within a temperature range of 200° C. or higher and 280° C. or lower was extremely long, which caused problems in productivity. Moreover, the carboxyl group content of the obtained PAS was low. The reason for this is not clear, but it is presumed that the long polymerization time is the cause. Furthermore, since no trihalogenated aromatic compound was used, the degree of dispersion was low.

Claims (6)

A polyarylene sulfide with a chloroform extractable content of 0.5% by weight or more and 2.0% by weight or less, which has a melt flow rate measured at 315°C and a load of 5000g in accordance with ASTM D 1238-70. 5g/10 minutes or more and 300g/10 minutes or less, the cooling crystallization temperature measured by a differential scanning calorimeter (DSC) at a cooling rate of 20°C/min is 190°C or more and 230°C or less, and the carboxyl group content is is 35 μmol/g or more and 100 μmol/g or less. The polyarylene sulfide according to claim 1, characterized in that the degree of dispersion expressed by weight average molecular weight/number average molecular weight is 5.5 or more and 15.0 or less. A method for producing polyarylene sulfide in which a sulfidating agent, a dihalogenated aromatic compound, and a trihalogenated aromatic compound are reacted in the presence of an alkali metal hydroxide and an alkali metal carboxylate in an organic polar solvent, at least the following: The method for producing polyarylene sulfide according to claim 1 or 2, characterized in that steps 1 to 4 are performed.
Step 1: In an organic polar solvent, 0.06 mol or more and 0.29 mol or less of an alkali metal carboxylate are present with respect to 1.00 mol of the sulfidating agent, and dihalogenation is performed with respect to 1.00 mol of the sulfidating agent. Presence of an aromatic compound of 0.99 mol or more and 1.03 mol or less and a trihalogenated aromatic compound of 0.10 mol% or more and 1.00 mol% or less, and reacting within a temperature range of 200°C or more and 280°C or less Polyarylene sulfide polymerization process.
Step 2: A step of distilling off the organic polar solvent from the mixture obtained at the end of the reaction to obtain a solid containing polyarylene sulfide.
Step 3: Following Step 2, the solid material containing polyarylene sulfide is washed with water and then treated with an acid.
Step 4: Following Step 3, a step of washing polyarylene sulfide with an organic solvent. 4. The method for producing polyarylene sulfide according to claim 3, wherein in step 1, water is present in the reaction vessel in an amount of 0.50 mol or more and 1.50 mol or less per 1.00 mol of the sulfidating agent. 4. The method for producing polyarylene sulfide according to claim 3, wherein in step 1, the polymerization time including temperature increase/decrease time within a temperature range of 200° C. or more and 280° C. or less is 120 minutes or more and 240 minutes or less. . 4. The method for producing polyarylene sulfide according to claim 3, further comprising performing a heat treatment step of heat-treating the polyarylene sulfide after step 4.