JPH072845B2 - Method for producing polyphenylene sulfide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a method for producing polyphenylene sulfide. Specifically, it relates to a method for producing high-purity polyphenylene sulfide.

<Conventional Technology and Problems> Polyphenylene sulfide (hereinafter abbreviated as PPS) has excellent properties as an engineering plastic, such as chemical resistance, dimensional stability, and heat resistance. However, there are problems in the morphology and purity of PPS, and improvement of these is desired. For example, since the particle size of the polymer is small, the powder is scattered during handling and the yield is lowered, the working environment is deteriorated by this dust, and the poor biting and kneading in the extrusion process are often caused. Further, since PPS usually contains about 1000 to 5000 ppm of sodium salt as an impurity, it may cause inconvenience such as deterioration of electrical characteristics when used for sealing electronic parts such as ICs and transistors. there were.

Conventionally, as a method for producing PPS having a large particle size, JP-A-5
No. 9-1536, and JP-A-57-108135 and JP-A-57-108136 are proposed as methods for purifying PPS. However, these improve the particle diameter and the purity individually, and cannot solve the above problems at the same time. Therefore, two steps must be taken, resulting in a high manufacturing cost.

<Means for Solving Problems> In view of the situation as described above, the present inventors have found that PPS with high purity is used.
As a result of earnest studies on the production method, it was found that the above problems can be solved all at once by adding an acid in the latter stage of the polymerization reaction or after the completion of the polymerization reaction, and the present invention has been achieved.

That is, the present invention is a PPS characterized by polymerizing a polyhalogenated aromatic compound and a sulfidizing agent in a polar solvent, adding an acid in the latter stage of the polymerization reaction or after the completion of the polymerization reaction, and lowering the temperature with stirring. A manufacturing method is provided.

The polyhalogenated aromatic compound used in the present invention is a dihalobenzene such as p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene and dibromobenzene, and as a copolymer component which can be used in combination therewith, Halogenated aromatic compounds having two or more halogen atoms directly bonded to an aromatic nucleus, for example, tri-chlorobenzene, tetrachlorobenzene, dichloronaphthalene, trichloronaphthalene, tribromobenzene, dibromonaphthalene, jodobenzene, trichlorobenzene. Iodobenzene, dichlorodiphenyl sulfone, dibromodiphenyl sulfone, dichlorobenzophenone, dibromobenzophenone, dichlorodiphenyl ether, dibromodiphenyl ether, dichlorodiphenyl sulfide, dibromodiphenyl sulfide, dichlorobiphenyl And dibromobiphenyl and mixtures thereof. In order to increase the viscosity of the polymer due to the branched structure, a small amount of a polyhalo aromatic compound having 3 or more halogen substituents in one molecule may be used in combination with the dihalo aromatic compound.

Examples of the sulfidizing agent used in the present invention include an alkali metal sulfide compound alone, a combination of the compound or another sulfur source and an alkali metal hydroxide compound, and the like.

Alkali metal sulfide compounds include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, and mixtures thereof. Such alkali metal sulfide compounds can be used as hydrates and / or aqueous mixtures or in anhydrous form. There is no problem even if a small amount of alkali metal hydroxide is added in order to react with a small amount of alkali metal disulfide and alkali metal thiosulfate present in the alkali metal sulfide. In addition, as the alkali metal sulfide compound, sodium sulfide of 1-2 dihydrate is preferable.

Other sulfur sources are, for example, alkali metal hydrosulfide compounds, hydrogen sulfide, thioamides, thioureas, thiocarbanates, thiocarboxylic acids, carbon disulfide, thiocarboxylates, sulfur, phosphorus pentasulfide and the like. A preferred sulfur source is an alkali metal hydrosulfide compound. Particularly, the alkali metal hydrosulfide compound includes lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide and a mixture thereof. Such alkali metal hydrosulfide compounds can be used in the form of hydrates and / or aqueous mixtures or anhydrous. As such an alkali metal hydrosulfide compound, sodium hydrosulfide is preferable, and it is used in combination with an alkali metal hydroxide compound. Instead of the compound, sodium N-methyl-4-aminobutyrate or an alkali metal carbonate compound is used in combination. Is also good.

Examples of alkali metal hydroxide compounds include potassium hydroxide, sodium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide and mixtures thereof, with sodium hydroxide being preferred.

The ratio of the sulfur source to the alkali metal hydroxide compound is 0.8 mol of the alkali metal hydroxide compound to 1 mol of the sulfur element.
~ 3.0 mol is suitable. In particular, when used in combination with an alkali metal hydroxide compound, the amount used is appropriately in the range of 0.9 to 1.2 mol per 100 mol of the alkali metal hydrosulfide compound. When the alkali metal carbonate compound is used together, about 1/2 of the use ratio of the alkali metal hydroxide compound is suitable. or,
When sodium N-methyl-4-aminobutyrate is used in combination, the amount used is 0. 1 with respect to 1.00 mol of alkali metal hydrosulfide.
A range of 9 to 1.2 mol is suitable.

When each hydrate of the above-mentioned alkali metal sulfide compound or alkali metal hydrosulfide is used, it is necessary to dehydrate it in a solvent in advance and then use it in the reaction. When dehydrating the alkali metal hydrosulfide, it is better to allow the alkali metal hydroxide compound or sodium N-methyl-4-aminobutyrate to coexist.

Examples of the organic amide-based polar solvent used in the method of the present invention include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and N-ethyl-2.
-Pyrrolidone, N-methyl-ε-caprolactam, hexamethylphosphoramide, etc. or a mixture thereof. Of these solvents, N-methyl-2-pyrrolidone (NMP) is particularly preferable.

The amount of the sulfidizing agent used in the present invention is 0.8 to 1.2 mol of sulfur element per mol of the dihaloaromatic compound,
It is preferably selected to be 0.9 to 1.1 mol. or,
The amount of the organic polar solvent used is in the range of 2.5 to 20 and preferably in the range of 3 to 10 in terms of molar ratio with respect to the dihaloaromatic compound.

The reaction temperature at which the polymerization is carried out in the present invention is generally 200 ° C to 330 ° C.
C, preferably 210-300C. The pressure should be in a range that keeps the polymerization solvent and the haloaromatic compound, which is the polymerization monomer, substantially in the liquid phase, generally 1.1 k.
^{g / cm 2 ~200kg / cm 2} , and preferably selected from the range of ^{1.1kg / cm 2 ~20kg / cm 2} . The reaction time varies depending on temperature and pressure, but is generally in the range of 10 minutes to about 72 hours, preferably 1 hour to 48 hours.

PPS can be produced by mixing a polyhaloaromatic compound, a sulfidizing agent and a polymerization aid and heating them preferably under an inert atmosphere. The order of mixing the respective components is not particularly limited, and it is carried out by adding the above components partially in small portions or at one time during the polymerization step.

The acid in the present invention means a proton donor of an organic acid or an inorganic acid. For example, organic acids include formic acid, acetic acid,
Propionic acid, 2-methylpropionic acid, oxalic acid, tartaric acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, 2-methyloctanoic acid, 1-decanoic acid, 4-ethyltetradecanoic acid, octadecanoic acid, cyclohexanecarboxylic acid, cyclo Dodecanecarboxylic acid, benzoic acid, acrylic acid, adipic acid,
Carboxylic acids such as phthalic acid, succinic acid, citric acid, maleic acid, glutamic acid, aminopropionic acid, polyacrylic acid, naphthalene-α-sulfonic acid, naphthalene-β
-Sulfonic acids such as sulfonic acid, paratoluenesulfonic acid, methanesulfonic acid, and benzenesulfonic acid; sulfonic acids such as benzenesulfonic acid and paratoluenesulfonic acid; and inorganic acids such as hydrochloric acid, hydrobromic acid, iodic acid, and fluoric acid. Hydrogen halides such as acids, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, carbonic acid, boric acid, silicic acid and phosphoric acid, polyphosphoric acid, phosphorous acid, methanephosphonic acid, ethane-1-phosphonic acid, propane-1- Phosphonic acid, butane-1-phosphonic acid, butane-2-phosphonic acid, pentane-
1-phosphonic acid, cyclohexane-1-phosphonic acid, vinyl-1-phosphonic acid, propene-2-phosphonic acid, butene-2-phosphonic acid, indene-2-phosphonic acid, phenylmethanephosphonic acid Acid, (4-methyl-phenyl) -methane-phosphonic acid, β-naphthyl-methanephosphonic acid, 2-phenyl-ethane-1-phosphonic acid, 2,2-diphenyl-ethane-1-phosphonic acid , 4-Phenyl-butane-1-phosphonic acid, 2-phenyl-ethylene-1-phosphonic acid, 2,2-diphenylethylene-phosphonic acid, phenyl-acetylene-phosphonic acid, 4-phenyl-butadiene- Phosphonic acid, benzene-phosphonic acid, 4
Phosphoric acids such as -methyl-benzene-phosphonic acid and 2-phenoxy-ethane-1-phosphonic acid.

In the present invention, an acid is added after the PPS polymerization reaction or after the completion of the polymerization reaction, and the temperature is lowered with stirring. Since the acid may affect the polymerization reaction, the acid is added after the latter stage of the polymerization reaction, that is, when the reaction rate of the monomer is 90% or more, preferably after the completion of the polymerization reaction. The addition amount of the acid can be arbitrarily set within the range in which the effect of the present invention is exhibited, depending on the degree of polymerization of PPS, the type and amount of the solvent used, and the required particle size. 1-500%, preferably 10-200%, based on polymer weight
To use.

The acid is added in the latter stage of the polymerization reaction or after the completion of the polymerization reaction, but the temperature in the reaction vessel at the time of addition is not particularly limited. However, in the present invention, at the time of addition of acid or after the addition of acid, it is essential that the temperature is equal to or higher than the temperature at which PPS dissolves. ) It is advantageous to add the acid above. After adding an acid and maintaining the temperature above the melting temperature of PPS for a predetermined time, the cooling operation is started while stirring.
At this time, if the stirring speed is too slow, the particle diameters tend to become uneven, so the stirring speed is 100 cm / min or more, more preferably 1000 cm / min or more, in terms of the peripheral speed of the stirring blade. Also, if the cooling rate is too fast, the particle size becomes non-uniform, so rapid cooling should be avoided. From this viewpoint, the cooling rate should be 20 ° C / min or less. At the above cooling rate up to the melting temperature of PPS, preferably the melting temperature of PPS
Remove after cooling to below 10 ℃. The extract is granular PP
It is a mixture of S, particulate PPS, a side reaction salt, a reaction solvent, an acid, etc., and granular PPS can be obtained by a known method. For example, after selecting only PPS having a large particle size from the above extract using a metal mesh, washing and drying such as normal water washing may be performed, or the above extract is subjected to distillation to remove the solvent, and then A method in which the mixture is washed with water and dried to obtain a mixture of PPS in the form of granules or particles and then classified can be used.

<Action and Effect> According to the production method of the present invention, by adding an acid after the polymerization reaction of PPS or after the polymerization reaction is completed, the purity is high,
Moreover, granular PPS can be obtained at low cost. Since powder scattering and extrusion work troubles in the post-process can be eliminated and PPS that improves the electrical characteristics of molded products can be supplied at a low cost, it is expected that demand for electrical and electronic parts will greatly expand. In addition to these uses, they are also used for machines, automobile parts, tubes, pipes, fibers, films and blow molded products.

<Example> Hereinafter, the method of the present invention will be described with reference to Examples. Incidentally, PP
The sodium salt in S was obtained by decomposing a granular or powdery polymer with sulfuric acid in a platinum crucible, diluting it with distilled water, and then quantifying the sodium metal element by flame photometry to determine the sodium content (content for PPS polymer, The unit is ppm).

The low molecular weight component in PPS was expressed as an acetone-soluble component (content relative to PPS polymer, unit weight%) by calculating the extraction amount by refluxing the polymer for 5 minutes with a Soxhlet type extractor using acetone as an extraction solvent.

The logarithmic viscosity [η] of PPS was measured at 206 ° C. in α-chlornaphthalene at a polymer concentration of 0.4 g / 100 ml solution, It is the value calculated according to.

The particle size distribution of PPS was determined by a powder tester (manufactured by Hosokawa Micron Laboratories, Inc.) using a sieve for measuring the degree of agglomeration and vibrating for 5 minutes with an electromagnetic shaker to determine the weight percentage. Granules of 590 μm or more (28 mesh residue)
It shall be called PS.

Examples 1-2, Comparative Examples 1-2 1 N-methylpyrrolidone 260 g, 60% in autoclave
Charge 78 g of sodium sulfide flakes (0.6 mol as anhydrous Na ₂ S) and 0.4 g (0.01 mol) of sodium hydroxide,
While stirring in a nitrogen atmosphere, the temperature was gradually raised from 160 ° C. to 205 ° C. over 1.5 hours, and a fraction consisting of 17.5 g of water and 0.9 g of N-methylpyrrolidone was removed to the outside of the system.

Then, 92.6 g (0.62 mol) of p-dichlorobenzene was added to N 2
-Methylpyrrolidone dissolved in 30 g and then charged, 225
℃, maximum pressure 3.2kg / cm ² for 2 hours, 265 ℃, maximum pressure
The reaction was carried out at 8.8 kg / cm ² for 2 hours. Next, a mixed solution of the acid shown in the table and 50 g of N-methylpyrrolidone was added all at once to the reaction system from the dropping tank, and 15 minutes after the addition was completed, the temperature was lowered to 205 ° C. at a rate of 1 ° C./min. The stirring speed during the temperature lowering operation was 400 rpm (the peripheral speed of the stirring blade was about 4800 cm / min). 2
After the temperature was lowered to 05 ° C, the mixture was allowed to cool to room temperature with gentle stirring. Take out the whole amount of the reaction mixture slurry, dry it under reduced pressure, wash it with water, separate the polymer by filtration, and dry it according to the conventional procedure, measure the particle size distribution of the polymer, and use granular PP.
The yield of S was determined. Next, the sodium content, the acetone-soluble component and the logarithmic viscosity [η] of this granular PPS were measured. The results are shown in the table.

As shown in the table, it is understood that according to the method of the present invention, granular PPS having a high purity and a large particle size can be obtained.

Claims (1)

[Claims] 1. A method for producing a polyphenylene sulfide, which comprises polymerizing a polyhalogenated aromatic compound and a sulfidizing agent in a polar solvent, adding an acid in the latter stage of the polymerization reaction or after the completion of the polymerization reaction, and lowering the temperature with stirring. Method.