JPH0371456B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing polyarylene sulfide, and more specifically, it relates to a method for producing polyarylene sulfide, which has high melt viscosity, high whiteness, excellent thermal stability, and a 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 can be made into molded products by injection molding or extrusion, or by melt extrusion and post-extrusion stretching and heat setting. As a result, it is widely used in fibers, films, and metal protective films as sealing materials and coatings for ICs and 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. is even more difficult. For this reason, it is necessary to add a certain amount of polyvalent halogen aromatic compound during the polymerization reaction, or after the polymerization reaction.
It has been attempted to increase the melt viscosity by causing branching and crosslinking reactions by heating. 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,
No.-12240 proposes the use of alkali metal carboxylates, and JP-A-55-40738 proposes the use of alkaline earth metal fatty acid salts. Further, U.S. Patent Specification No. 4038260 describes alkali metal salts of organic sulfonic acids, JP-A No. 55-43139 discloses specific alkali metal salts of aromatic sulfonates, and JP-A No. 56-20030 describes tri-alkali metal phosphates. JP-A-56-20031 discloses a dialkali metal salt of phosphonic acid. 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-mentioned polymerization aid, in order to obtain PPS with a high melt viscosity, a large amount of the polymerization aid, such as an equimolar amount or about 0.2 mole relative to the alkali sulfide, 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 grayish white.
So far, nothing of pure white color has been obtained. This is because coloration occurs mostly during the polymerization reaction, and although additives can improve thermal stability and reduce the degree of acceleration of coloration in subsequent processes, it has been difficult to increase whiteness. be. If the whiteness is poor,
It has been desired to obtain a polymer with a high degree of whiteness after the polymerization reaction, since it cannot be marketed not only for molding purposes but also for film and fiber applications. As explained above, it satisfies all the characteristics of high melt viscosity or intrinsic viscosity, low electrolyte content, high whiteness, and good thermal stability.
It has been extremely difficult to economically and stably polymerize PPS using a small amount of polymerization aid 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 salt of a phenolic aromatic sulfonic acid represented by the following general formula, and (B) an alkali metal hydroxide. and/or a method for producing polyarylene sulfide, which is characterized in that the reaction is carried out in the presence of an alkali metal alcoholate. (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 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, 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 react with alkali metal sulfide compounds, but they are used to increase the melt viscosity by introducing a branched structure into the polymer in order to advance the polymerization reaction efficiently or to control the crystallization rate. A tri-substituted or tetra-substituted 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-dichlorodiphenylsulfone, 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 where 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. For example, Ar

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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 (schifuric acid), 2-naphthol-1
-Sulfonic acid (oxypieric acid), 1-naphthol-4-sulfonic acid (nevilleinteric 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:
Specifically, sodium hydroxide, potassium hydroxide,
Examples include lithium hydroxide, sodium methylate, sodium ethylate, potassium methylate, potassium ethylate, lithium methylate, lithium ethylate, and the like. 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. Note that (A) and (B) may be mixed into the reaction system at the same time, or 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) an alkali metal salt of a phenolic aromatic sulfonic acid and (B) an alkali metal hydroxide and/or an alkali metal alcoholate are added all at once or gradually, but they may be present initially. . After removing water from the reaction system, the temperature of the system is reduced to approx.
Cool to 150-180℃. Here, the polyhalogen aromatic compound is further added with a solvent if necessary. Note that if the mixture of (A) and (B) has been subjected to anhydrous or heated reaction to remove the alcohol, it may be added at this point. 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 the organic solvent, salt and polymerization aid and dry.
After or during cooling of the reaction vessel, the reactants may be transferred to hot water or water, and then the same operations as above may be performed. After drying, a white powdery polymer is isolated. (Function) Although the effect of the alkali metal salt of phenolic aromatic sulfonic acid in the present invention is not fully clear, it is thought that the phenolic hydroxyl group brings about improvement in thermal stability and whiteness. Furthermore, the phenolic hydroxyl group affects the solubility and precipitation of the polymer in the reaction system, causing the polymer to precipitate into fine powder, and
It is expected that this substance itself affects the separation from the polymer and the separation of salts. (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. Note that measurements of various physical properties were carried out by the methods shown below. (Melt viscosity) This is a value measured at 300°C using a Koka type flow tester (CFT500 type A manufactured by Shimadzu Corporation). Measurement was carried out with a nozzle diameter of 1.0 mm, L/D=10, and a load of 50 kg/cm ² . (Whiteness) Expressed as an L* value measured using a colorimeter (CR-100 model manufactured by Minolta Camera) as a tablet with a thickness of 3.5 mm and a diameter of 18 mm. (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 1 220 ml of N-methylpyrrolidone and 480 g of sodium sulfide nonahydrate were placed in the stainless steel reaction vessel equipped with a cooling tower from 2.
(2 mol), 46.4 g (0.2 mol) of sodium p-phenolsulfonate dihydrate, and 8 g (0.2 mol) of sodium hydroxide, and heated under a nitrogen gas atmosphere.
The temperature was raised to 205°C with stirring, and after distilling off 330ml of water, the reaction system was cooled to 180°C. The reaction product was transferred to a stainless steel autoclave equipped with a stirrer in step 2, which was temperature controlled at 180°C under a nitrogen atmosphere, and 294 g (2 mol) of P-dichlorogunzene and 1.1 g of 1,2,4-trichlorobenzene were added to the reaction system. (0.006 mol) and 180 ml of N-metal pyrrolitone were added. Then seal the autolube and
1 hour from 180℃ to 240℃ while stirring, 240℃
The polymerization reaction was carried out at 270°C for 1 hour and at 270°C for 2 hours. 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, 196 g of white PPS was obtained. Obtained PPS IV = 0.24, MV = 3200 poise,
The whiteness L value was 91, and the Na content was 280 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 neville internate 44.8
(0.2 mol) and 8.0 g (0.2 mol) of sodium hydroxide were charged, the temperature was raised to 205°C with stirring under a nitrogen gas atmosphere, 100 ml of water was distilled off, and the reaction system was cooled to 180°C. did. 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-
28.2 g (0.6 mol) of dichlorobenzene and 1,2,
0.33 g (0.0018 mol) of 4-trichlorobenzene and 200 ml of N-methylpyrrolidone were added. Seal the autoclave and heat to 180℃ with stirring.
Polymerization reaction was carried out from 240°C to 260°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 washing was repeated several times with hot water and acetone. After drying, 62 g of white powder PPS was obtained. Obtained PPS IV = 0.20, MV = 700 poise,
The whiteness L value was 81, and the Na content was 800 ppm. Comparative Example 1 In the same manner as in Example 1, a dehydration reaction was carried out without adding sodium p-phenolsulfonate and sodium hydroxide, and p-dichlorobenzene, 1,2,4-trichlorobenzene and N-methylpyrrolidone were treated in the same manner. was introduced to cause a polymerization reaction.
As a result, 180 g of light gray powdered 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-methylpyrrolidone 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 was 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 such a configuration has excellent flame retardancy, 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, the polymerization aid can be easily removed 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.

Claims (1)

[Scope of Claims] 1. In an organic polar solvent, an alkali metal sulfide compound and a polyhalogen aromatic compound are combined with (A) an alkali metal salt of a phenolic aromatic sulfonate represented by the following general formula and (B) alkali metal water. A method for producing polyarylene sulfide, which comprises reacting it in the presence of an oxide and/or an alkali metal alcoholate. (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 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 oxide and/or alkali metal alcoholate is present in a molar ratio of 0.5 to 1.5 to the hydroxyl group in (A) the alkali metal salt of the phenolic aromatic sulfonic acid. A method for producing polyarylene sulfide according to item 1.