JPH0254371B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to polyphenylene sulfide (hereinafter referred to as
The present invention relates to a method for producing PPS (abbreviated as PPS), and more specifically, it relates to a new method for producing PPS that has a high viscosity that can be melt-molded and has a low content of impurities consisting of electrolyte components. PPS is widely used as a molded product that takes advantage of its heat resistance, chemical resistance, etc. by melt-molding it into engineering plastics, films, fibers, etc. using methods such as injection molding and extrusion molding. As a general manufacturing method for such PPS, N
-p- in an organic amide solvent such as methylpyrrolidone
A method of reacting dichlorobenzene with sodium sulfide has already been published in Japanese Patent Publication No. 45-3368, and an improved polymerization method for obtaining poly-p-phenylene sulfide with a high degree of polymerization has been published using alkali metal carboxylic acid. The method of adding salt as a polymerization aid was published in 1972.
−12240. On the other hand, when applying PPS to films, fibers, or various electrical/electronic parts, inorganic electrolyte impurities such as salt contained in the polymer should be minimized to maintain the original moldability and electrical insulation properties of PPS. This is desirable. When high viscosity PPS containing inorganic electrolyte impurities is made into a film by, for example, uniaxial or biaxial stretching, there is a drawback that the stretching properties and the transparency of the film are significantly worse than that of highly pure PPS. Also, PPS
When used as a coating or sealing material for electronic components such as ICs, transistors, or capacitors, it is necessary to use salt, for example, to eliminate defects such as corrosion and disconnection of the electrodes and wiring of the electronic components, and increased leakage current. It is necessary to use polymers that are as free from electrolyte impurities as possible. However, in the above-mentioned PPS manufacturing method, almost the same amount of salt is produced as a by-product and precipitated at the same time as the produced polymer, and as a result, the polymer obtained by normal processing contains a considerable amount of salt. Resin molded products using such polymers have the drawback of inferior moldability and electrical properties compared to those using low-salt PPS. As a result of intensive studies to improve the above-mentioned drawbacks, the present inventors found that alkali metal sulfides and polyhaloaromatic compounds can be mixed with alkali metal sulfides and polyhaloaromatic compounds in organic polar solvents such as N-methylpyrrolidone. We discovered that by heating and reacting in the coexistence of salt and a specific polyoxyethylene ether compound, PPS with high viscosity and containing almost no electrolyte components such as common salt can be obtained.
We have arrived at the present invention. That is, the present invention combines an alkali metal sulfide and a polyhaloaromatic compound in an organic polar solvent with at least one compound selected from the group of alkali metal salts of organic carboxylic acids represented by the following formula A and the following formula B. This is a new method for producing PPS with high viscosity and low electrolyte component content, which is characterized by carrying out the reaction in the coexistence of at least one compound selected from the group of polyoxyethylene ether compounds. A: R ₁ (-COOM) _n (In the above formula, R ₁ is 1 to 30 carbon atoms
The tetravalent organic group M represents an alkali metal selected from lithium, sodium, potassium, rubidium and cesium, and m represents an integer of 1 to 4. ) B: R ₂ -O(-CH ₂ CH ₂ O) - _o H (In the above formula, R ₂ represents an alkyl group or aryl group having 8 to 30 carbon atoms, and n represents an integer of 3 to 90.) This book According to the method of the invention, the PPS powder obtained by washing after polymerization is boiled again in deionized water for a long time to reduce impurities, or the above PPS powder is boiled again in an organic amide solvent. Among them, it is possible to reduce the electrolyte content in PPS to the same level or more than the conventional method described above without using a method of reducing impurities by heating in the presence of alkali metal carboxylate or lithium halide. can. In other words, according to the method of the present invention, PPS with extremely low electrolyte content can be obtained in the polymerization reaction process due to the synergistic effect based on the addition of a specific polyoxyethylene ether compound and an alkali metal salt of an organic carboxylic acid. Compared to conventional methods, the process of repurifying the recovered PPS can be omitted, and it is possible to produce PPS with extremely low impurities at low cost and in a short period of time using only normal hot water washing. There are advantages. Furthermore, due to the synergistic effect based on the addition of the above-mentioned compounds, the method of the present invention produces PPS with a higher intrinsic viscosity than a similar method without using the above-mentioned additives or a similar method using only one of the additives. It also has the advantage of being obtainable. The monomers used in the method of the present invention, ie polyhaloaromatic compounds, are halogenated aromatic compounds having two or more halogen atoms directly bonded to an aromatic nucleus, specifically p-dichlorobenzene, m-
Dichlorobenzene, o-dichlorobenzene, trichlorobenzene, tetrachlorobenzene, dichloronaphthalene, trichloronaphthalene, dibromobenzene, tribromobenzene, dibromnaphthalene, diiodobenzene, triiodobenzene,
Dichlordiphenyl sulfone, dibromidiphenyl sulfone, dichlorbenzophenone, dibromobenzophenone, dichlordiphenyl ether,
Dibrom diphenyl ether, dichlorodiphenyl sulfide, dibrom diphenyl sulfide,
Examples include dichlorbiphenyl, dibrombiphenyl, etc. and mixtures thereof. Usually, a dihaloaromatic compound is used as a monomer, but in order to increase the viscosity of the polymer due to its branched structure, a small amount of a polyhaloaromatic compound having three or more halogen substituents in one molecule may be copolymerized. . Alkali metal sulfide compounds used in the method of the invention include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, and mixtures thereof. The alkali metal sulfides can be used as hydrates and/or aqueous mixtures or in anhydrous form. Such alkali metal sulfides can also be derived from aqueous alkali metals and alkali metal hydroxides.
Note that there is no problem in adding a small amount of alkali metal hydroxide to react with the alkali metal hydrosulfide and alkali metal thiosulfate present in a small amount in the alkali metal sulfide. The organic polar solvent used in the process of the invention should be substantially liquid at the reaction temperature and pressure conditions employed. Preferred organic polar solvents include formamide, acetamide, N
-Methylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, ε-caprolactam, N
Amides, ureas and lactams such as -methyl-ε-caprolactam, hexamethylphosphoramide, tetramethylurea, 1,3-dimethyl-2-imidazolidinone; Sulfones such as sulfolane and dimethylsulfolane; benzonitrile, etc. Nitriles; ketones such as methyl phenyl ketone, and mixtures thereof can be mentioned. Among these solvents, it is particularly preferable to use aprotic organic polar solvents such as amides, lactams, or sulfones. Alkali metal salts of organic carboxylic acids that can be used in the method of the present invention include lithium acetate, sodium acetate, potassium acetate, lithium propionate,
Sodium propionate, rubidium butyrate, lithium valerate, cesium hexanoate, lithium heptanoate, lithium cyclohexanecarboxylate, lithium benzoate, sodium benzoate, potassium benzoate, potassium m-toluate, lithium phenyl acetate, disodium succinate , disodium adipate, disodium sebacate, disodium decanedicarboxylate, disodium phthalate, disodium terephthalate, disodium isophthalate, trisodium trimellitate, tetrasodium pyromellitate, disodium toluene dicarboxylate, naphthalene dicarboxylate Examples include disodium acid, etc., compounds in which the alkali metal of the above compounds is replaced with any one of lithium, potassium, rubidium, and cesium, and mixtures thereof. These alkali metal salts of organic carboxylic acids may be either anhydrous salts or hydrates, and may also be used in the form of an aqueous solution. In the method of the present invention, the above-mentioned specific polyoxyethylene alkyl ether compounds or polyoxyethylene aryl ether compounds are used as additives for separating and removing impurities consisting of electrolyte components such as common salt from the PPS polymer produced in the polymerization reaction step. It is necessary to use compounds. As such a polyoxyethylene ether compound, it is possible to use a nonionic surfactant obtained by etherifying the terminal hydroxyl group of a polyoxyethylene glycol having a molecular weight of 150 or more with an alkyl group or aryl group having 8 to 30 carbon atoms. can. Specific examples include polyethylene glycol monooctyl ether, polyethylene glycol monolauryl ether, polyethylene glycol monocetyl ether, polyethylene glycol monostearyl ether, polyethylene glycol monooleyl ether, polyethylene glycol monooctyl phenyl ether, polyethylene glycol monononyl phenyl ether, and the like. Mixtures of these may be mentioned. In the method of the present invention, the amount of alkali metal sulfide used is usually in a molar ratio of 0.8 to 1.2, preferably 0.9 to 1.2, relative to the dihaloaromatic compound.
The range is 1.1. In addition, the amount of organic polar solvent used is
The molar ratio to the alkali metal sulfide is usually in the range of 2.5 to 20, preferably in the range of 3 to 10. The amount of the alkali metal salt of organic carboxylic acid used in the method of the present invention is expressed as a molar ratio to the alkali metal sulfide.
A range of 0.05 to 2 is preferred. The amount of polyoxyethylene ether compound used is usually 0.01 to 30% of the halogenated aromatic compound used as the monomer.
% by weight, preferably from 0.5 to 20% by weight
is within the range of When carrying out the method of the present invention, an alkali metal sulfide, an alkali metal salt of an organic carboxylic acid, or an alkali metal hydroxide is preferably added to the organic polar solvent under an inert gas atmosphere and a temperature condition ranging from room temperature to 130°C. Add to 150 or more while stirring.
At a temperature in the range of 230°C, preferably in the range of 170 to 210°C, most of the water in the system is expelled from the system under normal pressure. After cooling the contents, a polyhaloaromatic compound and a polyoxyethylene ether compound are added, and the reaction system is heated under pressure at a temperature ranging from 210 to 290°C, preferably from 230 to 280°C.
Carry out the polymerization reaction for 10 hours. After the reaction is completed, the reaction mixture is filtered in a conventional manner, washed several times with boiling water, and finally washed with acetone and dried to obtain the desired PPS. The PPS obtained in this way contains almost no impurities such as electrolyte components such as salt, and has a high purity.
It is possible to maintain the good electrical insulation properties inherent to PPS. At the same time, the PPS obtained in this way has a high melt viscosity without being thickened by thermal crosslinking treatment, so it is possible to perform not only injection molding but also extrusion molding, blow molding, etc. Therefore, it is extremely useful for forming films, fibers, various electric/electronic parts, etc. Furthermore, since such PPS contains almost no electrolyte components that corrode the electrodes and wiring of electronic components, it is suitable for semiconductors, ICs, capacitors, resistors,
It is also extremely useful as a coating or sealing material for various electronic components such as coils. Hereinafter, the method of the present invention will be explained according to examples. The intrinsic viscosity value [η] of PPS was measured at 206°C in α-chlornaphthalene at a polymer concentration of 0.4 g/100 ml solution, and was calculated according to the following formula [η] = ln (relative viscosity)/polymer concentration. . In addition, the sodium ion content in PPS was measured as follows. Collect 150 to 500 mg of PPS powder in a 50 ml Kjeldahl flask and add deionized water.
Add 10 ml and 5 ml of sulfuric acid for precise analysis, shake well, then add zeolite and heat to decompose. When the decomposition progresses and the mixture becomes blackish brown, and gas is no longer generated, it is cooled, then 2 to 3 drops of perchloric acid are added, and the mixture is further decomposed by heating. The above operation is repeated until the decomposition solution becomes colorless and transparent, and the sample is completely decomposed.
After decomposition, cool and wash into a 50 ml volumetric flask and dilute to the balance line. Using this as a test solution, use an atomic absorption spectrophotometer to measure the flame intensity using a nitrous oxide-acetylene flame and a measurement wavelength of 589 nm. Calculate the content of sodium ions in PPS by comparing with a calibration curve created using a commercially available sodium chloride standard solution. Example 1 1 N-methylpyrrolidone in an autoclave
350 g, 104.8 g (0.80 mol) of sodium sulfide hexahydrate, 115.2 g (0.80 mol) of sodium benzoate, and 0.4 g (0.01 mol) of sodium hydroxide were heated to 200°C under a nitrogen atmosphere while stirring for about 2 hours. The temperature was raised and 21 ml of water was distilled off. After cooling the reaction system to 150°C, p-dichlorobenzene
117.6g (0.80mol), N-methylpyrrolidone 80g
and 11.7 g of polyoxyethylene monooctyl phenyl ether (average molecular weight 646), and heated to 230°C.
The mixture was reacted at 260°C for 1 hour and then at 260°C for 3 hours. The internal pressure at the end of polymerization was 6.7 Kg/cm ² . After cooling the reaction vessel, the contents were filtered, and the solid content was boiled and washed three times with hot water, and further washed twice with acetone.
It was dried at 120° C. to obtain 81.3 g of pale gray-brown granular PPS polymer (yield 94%). The intrinsic viscosity of the polymer is
0.34, and the sodium ion content was 27 ppm. Example 2 117 g (0.80 mol) of p-dichlorobenzene and 0.44 g (0.3 mol % based on p-dichlorobenzene) of 1,2,4-trichlorobenzene were used as polyhaloaromatic compounds, and sodium benzoate 81.6g of lithium acetate dihydrate instead of
Polymerization was carried out under the same conditions as in Example 1, except that (0.80 mol) was used. 76.8 g of pale gray-brown particulate polymer was obtained (yield 89%). The intrinsic viscosity of the polymer was 0.42 and the sodium ion content was 21 ppm. Comparative Example 1 In the polymerization of Example 1, polyoxyethylene monooctyl phenyl ether (average molecular weight 646)
The same procedure as in Example 1 was carried out except that . Finally, 78.5 g of pale gray-brown particulate polymer was obtained (yield 91%). The intrinsic viscosity of the polymer is 0.29
The sodium ion content was 870 ppm. Comparative Example 2 Polymerization was carried out in the same manner as in Example 1 except that sodium benzoate and polyoxyethylene monooctylphenyl ether (average molecular weight 646) were not added. 75.1 g of gray-brown powdered polymer was obtained (yield 87%). The intrinsic viscosity of the polymer is 0.16 and the sodium ion content is
It was 1250ppm. Examples 3 to 9 In the method of Example 1, 117 g (0.80 mol) of p-dichlorobenzene was used as the polyhaloaromatic compound.
and 0.44 g of 1,2,4-trichlorobenzene
(0.3 mol % based on p-dichlorobenzene) and instead of the combination of polyoxyethylene monooctylphenyl ether (average molecular weight 646) and sodium benzoate, the polyoxyethylene ether shown in Table 1 was used. The same procedure as in Example 1 was carried out except that a polymerization aid consisting of a combination of a compound and an alkali metal salt of an organic carboxylic acid was added. The results are shown in Table 1. 【table】

Claims (1)

[Claims] 1. An alkali metal sulfide and a polyhaloaromatic compound are combined in an organic polar solvent with at least one compound selected from the group of alkali metal salts of organic carboxylic acids represented by the following formula A and the following formula B. A method for producing polyphenylene sulfide having a high viscosity and a low content of electrolyte components, which comprises reacting in the coexistence of at least one compound selected from the group of polyoxyethylene ether compounds shown below. A: R ₁ (-COOM) _n (In the above formula, R ₁ is 1 to 30 carbon atoms)
The tetravalent organic group M represents an alkali metal selected from lithium, sodium, potassium, rubidium and cesium, and m represents an integer of 1 to 4. ) B: R ₂ -O(-CH ₂ CH ₂ O) - _o H (In the above formula, R ₂ represents an alkyl group or aryl group having 8 to 30 carbon atoms, and n represents an integer of 3 to 90.)