JPH05156014A - Production of high-molecular weight polyphenylene sulfide - Google Patents

Abstract

PURPOSE:To provide the subject polyphenylene sulfide suitable for extrusion molding as well as injection molding. CONSTITUTION:The objective polyphenylene sulfide can be obtained by reaction under heating of an alkali metal sulfide (e.g. sodium sulfide) with a dihalobenzene in the presence of an organic amide solvent (e.g. N,N- dimethylacetamide) through the following two steps: (1) the first step: after polymerization until the conversion rate for the dihalobenzene reaches >=90%, an aromatic dihalo compound having in one molecule two halogen atoms activated by electron-attracting group (e.g. 4,4'-dichlorodiphenylsulfone) is added to the system to put further forward the reaction to produce a polyphenylene sulfide prepolymer having active halogen atom (s) at the molecular chain end (s); (2) the second step: this prepolymer is made to react with an alkali metal salt of polyphenol of the formula (Ar is 6-24C aromatic residue; M is alkali metal; (n) is 2-6).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing polyphenylene sulfide, and more particularly to a method for producing high molecular weight polyphenylene sulfide.

Polyphenylene sulfide (hereinafter abbreviated as PPS) has been attracting attention as a member for electric / electronic equipment and a member for automobile equipment by taking advantage of its excellent heat resistance and chemical resistance. In addition, various molded parts such as injection molding, extrusion molding,
Can be formed into films, sheets, fibers, etc.
Widely used in fields where chemical resistance is required.

[0003]

As a method for producing PPS, a method of reacting a dihaloaromatic compound with a sulfur source such as sodium sulfide in an organic amide solvent such as N-methylpyrrolidone is disclosed in Japanese Patent Publication No. 45-3368. There is.

However, since the polymer obtained by this method has a low molecular weight, it cannot be used as it is for applications such as injection molding. The low molecular weight polymer is heated and oxidized in air to be crosslinked to have a high molecular weight. Although it has been used for applications, even this high-molecular weight polymer has poor extrusion processability due to high degree of crosslinking and branching, and it has been difficult to form a film or fiber.

Therefore, a method of obtaining a high molecular weight PPS by a polymerization reaction has been proposed. As a typical example, as disclosed in JP-B-52-12240, R-COOM (R is a hydrocarbyl group, M is an alkali metal) is used as a polymerization aid, and the polymerization reaction is carried out in the presence thereof. Is the way. The high molecular weight polymer thus obtained is
It is considered to have excellent extrusion processability and applicability to films, fibers, etc.

However, in the above method, the polymerization aid used is required to have an approximately equimolar amount to sodium sulfide, and since lithium acetate, which has a large effect in increasing the molecular weight, is expensive, the production cost is high, which is industrially disadvantageous. is there. Also,
Another problem of this method is that since a large amount of water-soluble organic acid salt is allowed to coexist in the polymerization system for polymerization, a large amount of organic acid salt is mixed into the treated wastewater after polymerization, which is a pollution problem. Is likely to occur, and it is very expensive to exclude it.

Further, US Pat. No. 4,038,263 discloses the use of lithium halide as a polymerization aid. If lithium halide is used as a polymerization aid, the above pollution problems and wastewater treatment problems are solved, but lithium halide is less effective in increasing the molecular weight than lithium acetate and the like, and thus a high molecular weight polymer is obtained. It is essential to add a cross-linking agent such as a polyhaloaromatic compound containing 3 or more halogens per molecule as disclosed in JP-B-54-8719, and lithium halide is expensive, so that The manufacturing operation becomes complicated, such as the need for recovery. Another problem is that when lithium halide is used as a polymerization aid, the polymer is often attached to the reaction vessel.

Further, there is a method in which the polymerization is carried out in two stages, a former stage and a latter stage, in which the polymerization temperature and the water content in the system are changed in the former stage and the latter stage to make PPS into a linearly high molecular weight. -7332, JP-A-62-149725
It is disclosed in the publication. However, this method has a drawback that the polymerization time becomes long because the high-molecular weight is not achieved unless the first-stage polymerization is carried out at a relatively low temperature for a long time, resulting in a decrease in productivity.

On the other hand, without using the above-mentioned polymerization aid, 3
A method for obtaining a branched PPS having a high molecular weight by allowing a compound having one or more halogens to exist in a reaction system is disclosed in JP-A-53-53.
It is disclosed in JP-A-136100 and JP-A-59-197430. However, the PPS obtained by this method has a defect that it is easily gelled and its thermal stability is poor.

Further, a method of reacting a halogen terminal of PPS with a diphenol compound to obtain a high molecular weight PPS is disclosed in JP-A-2-209925. However, the halogen at the end of the PPS molecular chain is not activated by the electron-withdrawing group and is poor in the reaction with diphenol, so the effect of increasing the molecular weight is small.

[0011]

DISCLOSURE OF THE INVENTION The present invention is based on the above-mentioned conventional P
It is intended to provide a method for producing a high molecular weight PPS which solves the drawbacks of the PS production method.

[0012]

[Means for Solving the Problems] That is, according to the present invention, at least the following two steps are involved in producing a polyphenylene sulfide by heating and reacting a cured alkali metal with dihalobenzene in the presence of an organic amide solvent. The present invention relates to a method for producing a characteristic high molecular weight polyphenylene sulfide.

First step: conversion of dihalobenzene is 90
After the polymerization is carried out until it reaches a mol% or more, an aromatic dihalo compound having two halogens activated by an electron-withdrawing group in one molecule is added, and the reaction is further continued to activate the active group at the terminal of the molecular chain. A process for producing a polyphenylene sulfide prepolymer having a halogen.

Second step; the polyphenylene sulfide prepolymer obtained in the first step and an alkali metal salt of polyphenol represented by the general formula (I) Ar (OM) _n (I) (where Ar is a carbon number of 6 to 24). An aromatic residue having
M is an alkali metal, and n is an integer of 2 to 6).

The feature of the present invention is that it does not use a polymerization aid such as an alkali metal carboxylate and has a high molecular weight P that is thermally stable.
There is a point that PS can be economically produced through the following two steps in a short time, and each step will be described in detail below.

<First Step> This is a step of producing a PPS prepolymer having a halogen activated by an electron-withdrawing group at the end of the molecular chain, and the polymerization conditions are such that the conversion of dihalobenzene is 90% or more. After that, an aromatic dihalo compound having two halogens activated by an electron-withdrawing group in one molecule is added, and there is no particular limitation as long as the condition of continuing the reaction is satisfied. Good. Here dihalobenzene (hereinafter DH
The conversion rate (abbreviated as B) is calculated using the following formula.

Conversion rate (%) = 100-{(DHB residual amount (mol) -DHB excess amount (mol) / DHB charging amount (mol)} × 100 The DHB excess amount in the above formula means DHB at the time of charging. It means an excess amount when added in an equimolar amount or more with respect to the alkali metal sulfide existing at the end of dehydration.

When the conversion rate of DHB is less than 90%, a relatively large amount of unreacted alkali metal sulfide remains in the system, so that the aromatic dihalo compound activated by the electron-withdrawing group is left behind in these residual alkalis. It is not preferable because it reacts with the metal sulfide and does not efficiently react with the PPS chain end. Polymerization conditions other than the conversion rate of DHB are not particularly limited, but in order to efficiently obtain PPS in a short time, before introducing DHB into the polymerization system, the water content in the system should be 5 per mol of alkali metal sulfide. It is preferable to adjust it to be not more than mol, preferably not more than 2.4 mol, and more preferably 0.3 to 1.8 mol.

The amount of the organic amide solvent used is preferably 250 to 1000 ml per mol of the alkali metal sulfide, and the amount is 0.10 at a polymerization temperature of 200 to 300 ° C. under the above conditions.
5 to 30 hours, preferably 1 to 1 at 210 to 270 ° C
The condition of 5 hours is preferably used.

The alkali metal sulfide and DH used
The charging ratio of B was such that the chain end of the obtained PPS was made to have a thiolate excess and the active halogen was easily introduced into the chain end of the molecule by the reaction with the aromatic dihalo compound activated by the electron-withdrawing group. It is preferable that the amount of the substance is slightly excessive with respect to DHB. Specifically, the molar ratio is (alkali metal sulfide) :( DHB) = 1.00: 0.
The range of 95 to 0.99 is preferably used.

In this way, after increasing the conversion rate of DHB to 90% or more, the aromatic dihalo compound activated by the electron-withdrawing group is added into the polymerization system to introduce an active halogen at the terminal. The reaction conditions of this aromatic dihalo compound and PPS are as follows: after adding the aromatic dihalo compound in an amount of 0.05 to 20 mol% with respect to the charged alkali metal sulfide,
It is preferable to react at 0 to 270 ° C. for 0.1 to 5 hours.

The melt viscosity of the prepolymer obtained in the first step is not particularly limited, but at least 5 poises is required for the PPS obtained after the completion of the second step to exhibit high heat resistance and excellent chemical resistance. As described above, it is preferably 20 poises or more.

<Second Step> In this step, the PPS prepolymer obtained in the first step is reacted with an alkali metal salt of polyphenol to obtain a high molecular weight PPS. This reaction can be carried out in a solution system using a solvent, or in a bulk system without using a solvent. When the reaction is carried out in a solution system, a polar aprotic solvent such as an organic amide is used as a solvent in an amount of 100 to 200 ml per PPS repeating unit, and an alkali metal salt of polyphenol is added in an amount of 0.05 to 10 mol% per PPS repeating unit. , 150-300
It is preferable to react at 0.1 ° C. for 0.1 to 30 hours. In this case, as an operation, the PPS prepolymer may be isolated after the first step, dispersed again in the solvent, and an alkali metal salt of polyphenol may be added to react, or the PPS and the prepolymer may be reacted after the first step. The second step may be continuously performed without isolation.

On the other hand, when the reaction is carried out in a bulk system, an alkali metal salt of polyphenol is added to the prepolymer isolated after the completion of the first step in an amount of 0.05 to 0.5 per PPS repeating unit.
It is preferable to add 10 mol% and react at 270 to 350 ° C. for 0.05 to 1 hour.

As the alkali metal salt of polyphenol, one prepared in advance outside the system may be used, or one obtained by reacting polyphenol with an alkali metal hydroxide and / or an alkali metal carbonate in the system may be used. You may use.

Next, the raw materials used in the present invention will be described.

Examples of the alkali metal sulfide used in the present invention include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and mixtures thereof. These alkali metal sulfides can be obtained by reacting an alkali metal hydrosulfide with an alkali metal base, or hydrogen sulfide with an alkali metal base, and prepared in situ prior to the addition of the dihaloaromatic compound into the polymerization system. However, it does not matter if it is prepared outside the system.

Preferred among the above alkali metal sulfides for use in the present invention is sodium sulfide.

Examples of the dihalobenzene used in the present invention include p-dichlorobenzene, p-dibromobenzene, p-diiodobenzene, m-dichlorobenzene, m-dibromobenzene, m-diiodobenzene and 1-chloro-4-bromo. Examples thereof include benzene and the like, and preferable examples include p-dihalobenzene such as p-dichlorobenzene. If it is less than 30 mol% with respect to p-dihalobenzene, m-dihalobenzene such as m-dichlorobenzene or o-dihalobenzene such as o-dichlorobenzene and dichloronaphthalene, dibromonaphthalene, dichlorodiphenylsulfone, dichlorobenzophenone, dichlorodiphenyl ether, Dichlorodiphenyl sulfide,
Copolymerization of dihaloaromatic compounds such as dichlorodiphenyl, dibromodiphenyl, dichlorodiphenyl sulfoxide, etc. may be used.

The polymerization solvent used in the present invention is preferably a polar solvent, and particularly preferably an aprotic organic amide stable to alkali at high temperature. Some examples of the organic amide used in the present invention include N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoramide, N-methyl-ε-caprolactam and N.
-Ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone and the like and mixtures thereof.

Next, the aromatic dihalo compound used in the present invention, which has two halogens activated by an electron-withdrawing group in one molecule, will be described.

The electron withdrawing group used in the present invention is P
It is stable under the polymerization conditions of PS, and the Hammett's substituent constant σ is a positive value based on halobenzene. Specifically _{-SO 2 -, - CO -,} - CN, -CO
OR, —SO ₃ R (wherein R represents hydrogen, a hydrocarbon group having 1 to 12 carbon atoms or an alkali metal) and the like are suitable as the electron withdrawing group.

Some examples of the aromatic dihalo compound having two halogens activated by an electron-withdrawing group used in the present invention are 4,4'-dichlorodiphenyl sulfone and 4,4'-difluoro. Diphenyl sulfone,
2,4-dichlorobenzophenone, 2,4'-dichlorobenzophenone, 4,4'-dichlorobenzophenone, 2,4'-difluorobenzophenone, 4,
4'-difluorobenzophenone, 2 ', 4'-dichloroacetophenone, 3', 4'-dichloroacetophenone, 2 ', 4'-difluoroacetophenone,
3 ', 4'-difluoroacetophenone, 2,6-dichlorobenzonitrile, 2,5-dichloroterephthalonirite, 2,4-difluorobenzonitrile,
2,5-difluorobenzonitrile, 2,6-difluorobenzonitrile, 3,5-difluorobenzonitrile, 4-bromo-2-chlorobenzoic acid, 5-bromo-
2-chlorobenzoic acid, 2-chloro-6-fluorobenzoic acid, 2,4-dichlorobenzoic acid, 2,5-dichlorobenzoic acid, 3,4-dichlorobenzoic acid, 3,5-dichlorobenzoic acid, 2, 5-dichloroterephthalic acid,
2,3-difluorobenzoic acid, 2,4-difluorobenzoic acid, 2,5-difluorobenzoic acid, 2,6-difluorobenzoic acid, 3,4-difluorobenzoic acid,
3,5-diiodoanthracenecarboxylic acid, 3,5-
Dichloroanthracenecarboxylic acid, 2,5-dichlorobenzenesulfonic acid, sodium 3,5-dichloro-2-hydroxybenzenesulfonate, 2,5-dichlorosulphonic acid, sodium 2,5-dichlorosulphonic acid, etc. Can be mentioned.

Next, the alkali metal salt of polyphenol used in the second step of the present invention will be described. The salt is represented by the following formula (I): Ar (OM) _n (I) (wherein Ar is an aromatic residue having 6 to 24 carbon atoms,
M is an alkali metal and n is an integer of 2 to 6) Obtained by reacting a polyphenol with an alkali metal hydroxide and / or an alkali metal carbonate. Some examples of polyphenols used here are 2 ',
4'-dihydroxyacetophenone, 2'5'-dihydroxyacetophenone, 2'6'-dihydroxyacetophenone, 3 ', 5'-dihydroxyacetophenone, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5 -Dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid ethyl ester, 2,4-dihydroxybenzoic acid 2-hydroxyethyl ester, 2,6-
Dihydroxybenzoic acid methyl ester, 2,4-dihydroxybenzophenone, 2,5-dihydroxy-
4′-methylbiphenyl, gallic acid, gallic acid butyl ester, gallic acid ethyl ester, gallic acid methyl ester, hexahydroxybenzene, hydroquinone, homocatechol, 3-methylcatechol, 4-n-hexylresorcinol, methoxyhydroquinone, methylhydroquinone , 5-methylpyrogallol, 2-methylresorcinol, 5-methylresorcinol, phenylhydroquinone, resorcinol,
2,2 ', 4,4'-tetrahydroxybenzophenone, tetramethylhydroquinone, 2', 3 ', 4'
-Trihydroxyacetophenone, 1,2,4-trihydroxybenzene, 2,3,4-trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2 ', 4', 6'-trihydroxypropiophenone , Trimethylhydroquinone, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1,6-
Dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,7-
Dihydroxynaphthalene, 1,1'-bis (2-hydroxynaphthyl) sulfide, 1,3-bis (4-hydroxyphenoxy) benzene, 1,4-bis (3-
Hydroxyphenoxy) benzene, 2,2-bis (4
-Hydroxyphenyl) butane, bis (4-hydroxyphenyl) ether, bis (o-hydroxyphenyl)
Methane, bis (p-hydroxyphenyl) methane, 2-
[Bis (4-hydroxyphenyl) methyl] benzyl alcohol, 2,2-bis (4-hydroxyphenyl)
Propane, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, 2,
2'-dihydroxydiphenyl, 2,5-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl and the like can be mentioned.

Examples of alkali metal hydroxides used are lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide and cesium hydroxide, and examples of alkali metal carbonates are lithium carbonate, sodium carbonate, Examples include potassium carbonate, rubidium carbonate, and cesium carbonate.

PPS from the reaction mixture after the end of the second step
In the case of the reaction in the solution system, the solvent is recovered by distilling, flushing, etc., and then the polymer is washed with water, or the reaction mixture is filtered to recover the solvent, and then the polymer is washed with water and recovered. PPS can be collected by a method or the like. When the reaction is carried out in a bulk system, PPS can be recovered by pelletizing the reaction mixture and then removing unreacted alkali metal salt of polyphenol and by-product salt by washing with water.

The PPS of the present invention has p
-It must contain 70 mol% or more of phenylene sulfide units. If it is less than 30 mol% of the structural unit,
It may contain one or more copolymerized units such as m-phenylene sulfide units, o-phenylene sulfide units, phenylene sulfide sulfone units, phenylene sulfide ketone units, phenylene sulfide ether units, and diphenylene sulfide units. ..

The PPS obtained as described above is a linearly polymerized PPS or a polymerized PPS having an appropriate degree of branching. Therefore, not only injection-molded products but also fibers, films and sheets. It is suitable for use as an extrusion molded product such as a pipe.

If necessary, glass fiber, carbon fiber,
Reinforcing fillers such as ceramic fibers such as alumina fibers, aramid fibers, wholly aromatic polyester fibers, metal fibers, potassium titanate whiskers, calcium carbonate, mica, talc, silica, barium sulfate, calcium sulfate,
Kaolin, clay, pyroferrite, bentonite,
Neserisite, Zeolite, Neferincinite, Attapulgite, Wollastonite, Ferrite, Calcium silicate, Magnesium carbonate, Dolomite, Antimony trioxide, Zinc oxide, Titanium oxide, Magnesium oxide,
It is also possible to mix inorganic fillers such as iron oxide, molybdenum disulfide, graphite, gypsum, glass beads, glass powder, glass balloons, quartz, quartz glass, and organic and inorganic pigments.

Further, a releasing agent such as wax, a silane-based or titanate-based coupling agent, a lubricant, a heat resistance stabilizer, a weather resistance stabilizer, a crystal nucleating agent, a foaming agent, a rust preventive, an ion trap agent, a flame retardant. A flame retardant auxiliary agent may be added if necessary.

Further, if necessary, polyethylene, polypropylene, polybutadiene, polyisoprene, polychloroprene, polystyrene, polybutene, poly α-methylstyrene, polyvinyl acetate, polyvinyl chloride, polyacrylic acid ester, polymethacrylic acid ester, polyacrylonitrile. , Nylon 6, nylon 66, nylon 6
Polyamide such as 10, nylon 12, nylon 11, nylon 46 and the like, polyester such as polyethylene terephthalate, polybutylene terephthalate and polyarylate,
Polyurethane, polyacetal, polycarbonate, polyphenylene oxide, polysulfone, polyether sulfone, polyallyl sulfone, polyphenylene sulfide sulfone, polyether ketone, polyether ether ketone, polyphenylene sulfide ketone, polyimide, polyamideimide, silicone resin, phenoxy resin, fluororesin, etc. It is also possible to use a mixture of one or more of the homopolymers, random or block polymers, and graft polymers.

[0042]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

The melt viscosity of PPS produced in the following Examples and Comparative Examples was measured with a Koka type flow tester (die; φ = 0.5 mm, L = 2 mm).
It was measured at 0 ° C. and a load of 10 kg.

Example 1 <First Step> 14.65 mol of sodium sulfide (Na ₂ S.2.9H ₂ O) was added to an autoclave having a volume of 15 l and N-.
Methyl-2-pyrrolidone (hereinafter abbreviated as NMP) (5 l) was added, and the mixture was stirred under a nitrogen stream and heated to 205 ° C., 450.
9 g of water and 2.3 g of NMP were distilled off. At this time, 0.
29 mol of sodium sulfide decomposed into hydrogen sulfide and disappeared. After cooling the system to 170 ° C., 14.1 mol of p-dichlorobenzene (hereinafter abbreviated as DCB) was added, the system was sealed under a nitrogen stream, the temperature was raised, and polymerization was carried out at 225 ° C. for 5 hours. After the completion of the polymerization, the system was cooled to room temperature, the residual DCB in the slurry was determined by gas chromatography, and the conversion rate was calculated using the above-mentioned formula, and was 96.0%.
A part of the slurry was sampled, filtered and washed repeatedly with water to isolate the polymer, and the melt viscosity was measured to find 63 poises.

1064 g of the slurry thus obtained
(Equivalent to 1.8 mol of Na ₂ S charged) and 0.036 mol of 4,4′-dichlorodiphenyl sulfone were charged into a 2 liter autoclave, the system was sealed under a nitrogen stream, and the temperature was raised to 230 ° C. for 2 hours. The reaction was carried out over time. After the reaction was completed, the system was cooled to room temperature, a part of the slurry was sampled, filtered,
The polymer was repeatedly washed with water, the polymer was isolated, and the melt viscosity was measured.

<Second Step> Bisphenol A 0.036
Mol and 0.072 mol of sodium hydroxide were added to the slurry after the completion of the first step, the system was sealed under a nitrogen stream, the temperature was raised, and the reaction was carried out at 230 ° C. for 3 hours. After completion of the reaction, the system was cooled, the content was thrown into a large amount of water to precipitate the polymer, which was separated by filtration and washed with pure water, and then heated and vacuum dried overnight to isolate the polymer. The yield of the obtained polymer was 175 g and the melt viscosity was 1700 poise.

Example 2 <First Step> The reaction between sodium sulfide and DCB was carried out at 225
Polymerization was carried out in the same manner as in Example 1 except that the heating was carried out at 2 ° C. for 2 hours and at 250 ° C. for 2 hours. The conversion rate of DCB is 9
The melt viscosity was 8.8% and the melt viscosity was 460 poise. This slurry was reacted with 4,4'-dichlorodiphenyl sulfone under the same operation and conditions as in Example 1. The melt viscosity of the obtained prepolymer was 470 poise.

<Second Step> In the same manner as in Example 1, bisphenol A was reacted with the prepolymer obtained in the first step. The yield of the obtained polymer was 177 g, and the melt viscosity was 1500 poise.

Examples 3 to 5 By the same operation as in Example 1, the reaction was carried out by changing the kind of polyphenol and the kind of aromatic dihalo compound activated by an electron-withdrawing group as shown in Table 1. The results are summarized in Table 1.

Example 6 200 g of the prepolymer obtained in the first step of Example 1, 0.037 mol of bisphenol A and 0.074 mol of sodium hydroxide were placed in a separable flask having a capacity of 500 ml and heated under a nitrogen stream. And reacted at 300 ° C. for 20 minutes. After the reaction was completed, the content was taken out and pulverized, and the obtained pellet was washed with warm water and dried to isolate the polymer. The yield of the obtained polymer was 190 g, and the melt viscosity was 2200 poise.

Comparative Example 1 The first step and the second step were carried out by the same operation except that the 4,4'-dichlorodiphenyl sulfone was not added in the first step of Example 1. The melt viscosity of the obtained polymer was 310 poise, which was a polymer having a lower melt viscosity than that of Example 1.

[0052]

[Table 1]

[0053]

As is clear from the above description, according to the present invention, a linearly polymerized PPS or a PPS having a high molecular weight and moderate branching can be obtained without the problems of the conventional method, The PPS thus obtained is suitable not only for injection molding but also for extrusion molding of films, fibers and the like.

Claims (1)

[Claims] 1. A method for producing a polyphenylene sulfide by heating and reacting an alkali metal sulfide and dihalobenzene in the presence of an organic amide solvent, wherein at least the following two steps are involved to produce a high molecular weight polyphenylene sulfide. Production method. First step: Polymerization is performed until the conversion rate of dihalobenzene reaches 90% or more, and then an aromatic dihalo compound having two halogens activated by an electron-withdrawing group in one molecule is added, and the reaction is continued. To produce a polyphenylene sulfide prepolymer having an active halogen at the end of the molecular chain. Second step; polyphenylene sulfide prepolymer obtained in the first step and an alkali metal salt of polyphenol represented by the general formula (I) Ar (OM) _n (I) (where Ar has 6 to 24 carbon atoms) Aromatic residue,
M is an alkali metal, and n is an integer of 2 to 6).