JPH0363975B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to a method for producing polyarylene sulfide, and more specifically, a method for producing polyarylene sulfide that has high melt viscosity, high whiteness, excellent thermal stability, and controlled crystallization rate. The present invention relates to a method for producing polyarylene sulfide having the following properties. Polyarylene sulfide has attracted attention in recent years as a heat-resistant plastic with melt moldability, and it has been used to make molded products by injection molding and extrusion, as well as by melt extrusion and post-extrusion stretching and heat setting. Therefore, it is widely used in fibers, films, and metal protective films as sealing materials or coatings for IC transistors by transfer molding. (Conventional technology) Conventionally, polyarylene sulfide (hereinafter referred to as PPS)
Japanese Patent Publication No. 3368/1983 discloses that a method for producing the compound is obtained by reacting an alkali fluid with a dihalogen aromatic compound in an organic polar solvent such as N-methylpyrrolidone. Polymers obtained by such methods have low melt viscosity and are difficult to melt extrude, and it is even more difficult to produce strong fibers and films by stretching after melt extrusion. For this reason, melt viscosity has been increased by adding a certain amount of a polyvalent halogen aromatic compound during the polymerization reaction or by heating to cause branching and crosslinking reactions after the polymerization reaction. On the other hand, the use of various polymerization aids has been studied as a method for increasing the melt viscosity or intrinsic viscosity without relying on the above-mentioned methods. For example, the special public official court in 1977-
No. 12240 includes alkali metal carboxylates, JP-A-Sho
No. 55-40738 proposes the use of alkaline earth metal fatty acid salts. Furthermore, US Pat.
No. 56-20030 contains trialkali metal phosphate, JP-A-Sho.
No. 56-20031 discloses dialkali metal phosphonic acid salts. Further, JP-A No. 58-22113 discloses a method of using an organic carboxylic acid metal salt or an organic sulfonic acid metal salt, and JP-A No. 58-206632 discloses a method of using an organic carboxylic acid or an organic sulfonic acid in combination with an alkali hydroxide. ing. Further, JP-A-59-25822 discloses that the electrolyte content can be reduced by using polyoxyethylene ether together with an alkali metal salt of an organic carboxylic acid. By employing the above method, it is possible to increase the melt viscosity or intrinsic viscosity, or to decrease the electrolyte content. (Problems to be Solved by the Invention) By the way, when using the above polymerization aid, in order to obtain PPS with a high melt viscosity, it is necessary to
A large amount of polymerization aid of about 0.2 to 1 mol is required.
Furthermore, when these polymerization aids are used, it is difficult to reduce the metal content in the polymer by ordinary washing with hot water, acetone, or the like. Normally, PPS generates a small amount of bubbles or a large amount of bubbles depending on the conditions during the melt extrusion or injection process, but this is due to the low thermal stability of the polymer, and is generally caused by oxidation of sulfur atoms in the polymer. This is thought to be due to the generation of sulfur dioxide. In order to prevent this, it has been proposed to add various additives. In addition, PPS is generally obtained in a light colored state, and depending on the polymerization aid, it becomes light brown or light gray, and to date no pure white product has been obtained. this is,
This is because coloring occurs almost during the polymerization reaction, and although additives can improve thermal stability and suppress the degree of acceleration of coloring in subsequent steps, it has been difficult to increase whiteness. If the whiteness is poor, the polymer cannot be marketed not only for molding purposes but also for film and fiber applications, so it has been desired to obtain a polymer with high whiteness after the polymerization reaction. As explained above, PPS that satisfies all of the characteristics of high melt viscosity or intrinsic viscosity, low electrolyte content, high whiteness, and good thermal stability, and has good processability and also has a small amount of polymerization aid It has been extremely difficult to carry out economical and stable polymerization using conventional methods. (Means for Solving the Problems) In view of the above circumstances, the inventors of the present invention have made extensive studies, and as a result, have found a polymerization aid that satisfies the various factors described above, and have completed the present invention. That is, the present invention combines an alkali metal sulfide compound and a polyhalogen aromatic compound in an organic polar solvent, (A) an alkali metal phenol aromatic sulfonic acid salt represented by the following general formula, (B) an alkali metal hydroxide, and This is a method for producing polyarylene sulfide, characterized in that the reaction is carried out in the presence of one or more of each of an alkali metal alcoholate and (C) an alkali metal salt of sulfate. (HO)m-Ar-(So ₃ M)n However, Ar is a divalent to tetravalent aromatic group having 6 to 24 carbon atoms, M is an alkali metal, and m and n each represent 1 or 2. The alkali metal sulfide compound used in the method of the present invention is lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide or cesium sulfide, or mixtures thereof, as well as hydrates or aqueous solutions thereof. In the case of a hydrate or an aqueous solution, it can be dehydrated from the reaction solution before adding the polyhalogen aromatic compound. Note that the alkali metal sulfide compound can be produced from an aqueous alkali bisulfide solution and an aqueous alkali hydroxide solution. Furthermore, the alkali bisulfide and alkali metal thiosulfate salts present in trace amounts in the alkali metal sulfide compound can be neutralized with a small amount of alkali hydroxide. The polyhalogen aromatic compounds used in the present invention include di-substituted, tri-substituted, and tetra-substituted polyhalogen aromatic compounds. Dihalogen aromatic compounds are mainly used as monomers to be reacted with alkali metal sulfide compounds, but they are used to introduce a branched structure into the polymer to increase the melt viscosity, to efficiently proceed with the polymerization reaction, or to speed up the crystallization rate. For control purposes, a trisubstituted or tetrasubstituted polyhalogen aromatic compound can be partially copolymerized. Examples of dihalogen aromatic compounds include p-disubstituted halogen compounds such as p-dichlorobenzene and 2,5-
Dichloro-p-xylene, 4,4-dichlorodiphenylsulfonic acid, 2,5-dichlorotoluene,
4,4-dichlorodiphenyl ether, dichlornaphthalene, dibromnaphthalene, dichlorobenzophenone, dibrombenzophenone, m-dichlorobenzene of m-substituted compounds, O- of O-di-substituted compounds Examples include dichlorobenzene. Tri- or tetra-substituted aromatic compounds include 1,2,4-trichlorobenzene, 1,2,3-
Trichlorobenzene, 2,4,6-trichlorobenzene, 2,4,6-trichlorotoluene, 1,
Examples include 2,4-tribromobenzene, 1,2,3-trichloronaphthalene, 1,2,3-trichloronaphthalene, and 1,2,3,4-tetrachloronaphthalene. Next, (A) phenolic aromatic sulfonic acid alkali metal salt used as a polymerization aid in the present invention is a compound represented by the following general formula. (HO)m-Ar-(SO ₃ M)n (Ar is a divalent to tetravalent aromatic group having 6 to 24 carbon atoms, M is an alkali metal, and m and n are each 1
or 2. ) For example, Ar is

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[Formula] etc., and among them, a phenylene group is preferred, and M includes sodium, lithium, potassium, etc. Specific examples of the alkali metal salt of phenolic aromatic sulfonic acid (A) include phenol-4-sulfonic acid, phenol-2-sulfonic acid, phenol-2,4-disulfonic acid, resorcin-4-sulfonic acid, resorcin-4,6-disulfonic acid,
Pyrocatechin-4-sulfonic acid, 2-oxytoluene-4-sulfonic acid, 3-oxytoluene-4
-Sulfonic acid, 4-oxytoluene-2-sulfonic acid, hydroquinone sulfonic acid, hydroquinone-
2,5-disulfonic acid, 2-naphthol-6-sulfonic acid (diefuric acid), 2-naphthol-1
-Sulfonic acid (oxypieric acid), 1-naphthol-4-sulfonic acid (nepyrulainteric acid), 2
-Naphthol-8-sulfonic acid (croucenoic acid)
Alkali metal salts such as Note that these may be any of anhydrous salts, hydrates, and aqueous solutions. Also,
The amount added is per mole of alkali metal sulfide compound,
The amount is 0.02 to 1.0 mol, preferably 0.05 to 0.15 mol. The (B) alkali metal hydroxide and/or alkali metal alcoholate to be used in combination with the (A) phenolic aromatic sulfonic acid alkali metal salt includes sodium hydroxide, potassium hydroxide, lithium hydroxide, and sodium hydroxide. Methylate, sodium ethylate, potassium methylate, potassium ethylate, lithium methylate, lithium ethylate, and the like. The alkali metal sulfate (C) is sodium sulfate, potassium sulfate, lithium sulfate, hydrates thereof, or aqueous solutions thereof. These moisture can be dehydrated from the reaction solution before adding the polyhalogen aromatic compound. The above (B) has a molar ratio to the hydroxyl group of (A).
It is preferably 0.5 to 1.5, more preferably 0.8 to 1.5, more preferably 0.9 to 1.1. If it is outside the above range, the polymerization reaction may not proceed efficiently or the polymer obtained in the reaction system may decompose again, which is not preferable. The molar ratio of (C) to the hydroxyl group of (A) is preferably 0.2 to 10, preferably 0.5 to 5. If it is outside the above range, the thermal stability in the polymerization reaction will be poor and the degree of polymerization may not be sufficiently increased, which is not preferable. Note that (A), (B) and (C) may be mixed into the reaction system at the same time, or the three may be mixed in advance and added to the reaction system. Examples of organic polar solvents used in the present invention include N-methylpyrrolidone, hexamethylphosphoric triamide, N-methylformamide, N,N' dimethylacetamide, caprolactam, N-methyl-ε
-Caprolactam, tetramethylurea, dimethylacetamide and the like. Next, we will specifically explain how to obtain PPS. First, an alkali metal sulfide compound is added to an organic polar solvent, nitrogen gas is preferably introduced into the mixture under a nitrogen atmosphere, and the temperature is gradually lowered while stirring.
Raise the temperature to 210℃. During this time, (A) phenolic aromatic sulfonic acid alkali metal salt, (B) alkali metal hydroxide and/or alkali metal alcoholate, and (C) alkali metal sulfate are added all at once or gradually. It may be left to exist. After removing moisture brought in from hydrates, aqueous solutions, etc. from the reaction system, or alcohol generated from alcoholates, the temperature of the system is lowered to approximately 150°C.
Cool to ~180°C. Here, the polyhalogen aromatic compound is added, and a solvent is further added as necessary. Note that the mixture of (A) and (B) may be added at this point if the alcohol has been removed in advance by anhydrous or heated reaction. The reaction system was then sealed and heated at approximately 210°C to 280°C for 10 to 280°C.
Gradually increase the temperature at 30Kg/cm ² for 1 to 2 hours, and then continue for 1 to 2 hours after the temperature reaches the specified maximum temperature.
Heat and react for 3 hours. The reaction is exothermic;
It is necessary to raise the reaction temperature with care so as not to raise the temperature too rapidly. After the reaction is complete, cool the reaction vessel, take out the reactants, filter the solvent, and wash with hot water, water, acetone, etc.
Remove organic solvent, salt and polymerization aid and dry. After or during cooling of the reaction vessel, the reactant may be transferred to hot water or water, and then the same operation as above may be performed. After drying, a white powdery polymer is isolated. (Action) Although the effect of (A) phenolic aromatic sulfonic acid alkali metal salt in the present invention is not fully clear, it is thought that the phenolic hydroxyl group improves thermal stability and whiteness. It will be done. Furthermore, the solubility of the polymer affects the precipitation of phenolic hydroxyl groups in the reaction system,
It is expected that the polymer will precipitate into a fine powder, and that it will also affect the separation from the polymer and the separation of salts. It is also believed that (C) the alkali metal sulfate salt enhances the thermal stability of the polymerized polymer in organic solvents. (Example) The method of the present invention will be specifically described below using Examples and Comparative Examples, but the present invention is not limited thereto. The various physical properties were measured using the methods shown below. (Melt viscosity) This is a value measured at 300° C. with a nozzle diameter of 1.0 mm, L/D=10, a load of 50 Kg/cm ² using a Koka type flow tester (CFT500 type A, manufactured by Shimadzu Corporation). (Whiteness) Measured using a chromaticity meter (CR-100 model manufactured by Minolta Camera) as a tablet with a thickness of 3.5 mm and a diameter of 18 mm, and expressed as an X value. (Na content) Na content was determined by dry ashing the polymer at 550°C, making it into a hydrochloric acid solution, and measuring it by atomic absorption spectrometry. Example 1 900 ml of N-methylpyrrolidone and 960.7 g of sodium sulfide nonahydrate were placed in the stainless steel reaction vessel with cooling tower of 5.
(4 mol), 61.9 g (0.26 mol) of sodium p-phenolsulfonate dihydrate, and 10.7 g (0.26 mol) of sodium hydroxide, and the temperature was raised to 205°C under nitrogen gas atmosphere while stirring for 2 hours. After distilling off 650 ml of water, the reaction system was transferred to a stainless steel autoclave equipped with a stirrer (No. 5) whose temperature was controlled at 180°C under a nitrogen atmosphere, and 588 g of p-dichlorobenzene was added to the reaction system.
(4 moles) 1,2,4 trichlorobenzene 2.18g
(0.012 mol) and 400 ml of N-methylpyrrolitone,
Furthermore, 284 g (2 moles) of sodium sulfate was added.
Next, the autoclave was sealed and 2 kg/kg was placed under a nitrogen atmosphere.
cm ² from 180℃ to 240℃ with stirring under pressure.
The polymerization reaction was carried out from 240°C to 270°C for 1 hour and 30 minutes, and at 270°C for 2 hours and 30 minutes. The internal pressure at the end of polymerization had risen to 16 kg/cm ² . After cooling the reaction vessel, the contents were taken out, N-methylpyrrolidone was filtered off, and washing was repeated several times with hot water and acetone. After drying, 392 g of white PPS powder was obtained. Obtained PPS IV = 0.27, MV = 3500 poise,
Whiteness L value = 90. The Na content was 400 ppm. Example 2 230 ml of N-methylpyrrolidone and 144.1 g of sodium sulfide nonahydrate were placed in the stainless steel reaction vessel equipped with a cooling tower from 2.
(0.6 mol), sodium nepirulinterate 44.8
g (0.2 mol) and sodium hydroxide 8.0 g (0.2
The reaction system was cooled to 180°C after 98ml of water was distilled off. The reaction product was transferred under a nitrogen atmosphere to a stainless steel autoclave equipped with a stirrer (No. 2) whose temperature had been previously controlled at 180°C. In this reaction system, p-
88.2 g (0.6 mol) of dichlorobenzene and 1,
2,4-trichlorobenzene 0.33g (0.018mol)
and 200 ml of N-methylpyrrolidone and 42.6 g (0.3 mol) of sodium sulfate were added. Seal the autoclave and heat to 180°C while stirring.
℃ to 240℃ for 1 hour, 240℃ to 260℃ for 1 hour
The polymerization reaction was carried out at 260°C for 2 hours and 30 minutes. After cooling the reaction vessel, the contents were taken out and N-methylpyrrolidone was filtered off, followed by repeated washing several times with hot water and acetone. After drying, 61 g of white powder PPS was obtained. Obtained PPS IV = 0.22, MV = 2000 poise,
The whiteness L value was 84, and the Na content was 700 ppm. Comparative Example 1 In the same manner as in Example 1, a dehydration reaction was carried out without adding sodium p-phenolsulfonate sodium hydroxide and sodium sulfate, and p-dichlorobenzene, 1,2,4-trichlorobenzene and N-methylpyrrolidone were was similarly introduced to carry out the polymerization reaction. As a result, a light gray powder
180g of PPS was obtained. The obtained polymer had IV=0.10, MV=80 poise, whiteness L value=79.0, and Na content 600 ppm. Comparative Example 2 220 ml of N-methylpyrrolidone, sodium sulfide nonahydrate, 144.1 g in the stainless steel container with a cooling tower from 2
(0.6 mol) and sodium p-toluenesulfonate (0.1 mol) were charged, and the temperature was raised to 205°C with stirring under a nitrogen gas atmosphere. After distilling off 100 ml of water, the reaction system was cooled to 180°C. The reaction product was transferred under a nitrogen atmosphere to a stainless steel autoclave equipped with a stirrer (No. 2) whose temperature had been previously controlled at 180°C. In this reaction system, 88.2 g (0.6 mol) of p-dichlorobenzene and 1,2,
0.33 g (0.0018 mol) of 4-trichlorobenzene and 200 ml of N-methylpyridone were added. The autoclave was sealed, and while stirring, the reaction was carried out from 180°C to 240°C for 1 hour, from 240°C to 260°C for 1 hour, and at 260°C for 2 hours. After cooling the reaction vessel, the contents were taken out, N-methylpyrrolidone was filtered off, and the mixture was washed several times with hot water and acetone. After drying, 60 g of off-white powdery PPS was obtained. The resulting polymer had an IV of 0.16, an MV of 200 poise, a whiteness L value of 79, and a Na content of 1100 ppm. Comparative Example 3 In Comparative Example 2, p-toluenesulfonic acid
When the reaction was carried out in the same manner as in Comparative Example 2 except that 0.1 mol of sodium hydroxide and 0.1 mol of sodium sulfate were present together with 0.1 mol, the polymerization reaction did not proceed at all. (Effects of the Invention) As described above, PPS obtained by employing the method of the present invention having the above structure has excellent flame retardancy, heat resistance, chemical resistance, electrical properties, etc. that PPS originally has. Of course, it also has high whiteness and high thermal stability. Furthermore, since PPS is obtained in the form of a fine powder after the polymerization reaction, it is easy to remove solvents, salts, or polymerization aids by simple washing, and as a result, PPS with a low electrolyte content can be obtained. . Furthermore, compared to conventional methods, PPS with less branching and high melt viscosity or intrinsic viscosity can be obtained with a small amount of polymerization aid, making it suitable for melt molding and extremely useful for applications such as engineering plastics, films, fibers, and sealing materials. It is. In addition, the PPS obtained by the method of the present invention has an appropriate crystallization rate, which is advantageous in the stretching process when processing into films and fibers, and in imparting high strength and elastic modulus to products. do.

Claims (1)

[Claims] 1. In an organic polar solvent, an alkali metal sulfide compound and a polyhalogen aromatic compound are combined into (A) an alkali metal salt of a phenolic aromatic sulfonate represented by the following general formula, (B) an alkali metal water A method for producing polyarylene sulfide, which comprises reacting in the presence of one or more oxides and/or alkali metal alcoholates and (C) alkali metal sulfates. (HO)m-Ar-(So ₃ M)n However, Ar is a divalent to tetravalent aromatic group having 6 to 24 carbon atoms, M is an alkali metal, and m and n each represent 1 or 2. 2. The method for producing polyarylene sulfide according to claim 1, wherein the alkali metal salt of phenolic aromatic sulfonate (A) is an alkali metal salt of paraphenolsulfonate. 3 (B) The alkali metal hydroxide and/or alkali metal alcoholate is present in a molar ratio of 0.5 to 1.5 to the hydroxyl group in the (A) phenolic aromatic sulfonic acid alkali metal salt. A method for producing polyarylene sulfide according to item 1. 4. The polyarylene according to claim 1, wherein (C) the alkali metal sulfate is present in a molar ratio of 0.2 to 10 to the hydroxyl group in the alkali metal salt of the phenolic aromatic sulfonic acid (A). How to make Rufid.