JP3155752B2 - Method for producing high molecular weight polyarylene sulfide - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing polyarylene sulfide (hereinafter referred to as PAS), and more particularly to a method for producing high molecular weight PAS. PAS is a thermoplastic resin with excellent properties such as heat resistance, chemical resistance, and dimensional stability of molded products, and is mainly used for automobile parts, electric / electronic parts,
It is used for machine parts.

The PAS obtained by the production method of the present invention is a polymer, so it is tough and excellent in impact resistance, and is used in a wider range of fields, including applications similar to conventional products as molded products, and is used for fibers, films, sheets, etc. Application is possible.

[Conventional technology]

A method for producing PAS by reacting an alkali metal sulfide represented by sodium sulfide and a dihalo aromatic compound represented by p-dichlorobenzene in an organic amide solvent is described in JP-B-45-3368. I have. However, PAS produced by this method has low molecular weight and low melt viscosity, and it has been difficult to form fibers, films, extruded sheets, and the like. Therefore, suitable for applications such as fibers, films, extruded sheets, etc.
A polymerization method utilizing various polymerization auxiliaries for producing PAS has been proposed. Representative examples include a method using an alkali metal carboxylate (Japanese Patent Publication No. 52-12240) and a method using an alkali metal sulfonic acid salt (U.S. Pat.
No. 8,260), a method using an alkali metal salt of an aromatic sulfonic acid (JP-A-55-43139), a method using an alkali metal halide (U.S. Pat. No. 4,038,263), and a method using a tri-alkaline phosphate (JP-A No. 4,038,263). No. 56-20030), and a method using an alkali metal salt or an alkaline earth metal salt of an aromatic carboxylic acid (JP-A-58-20663 and JP-A-59-219332). A method is also known in which an alkali metal sulfide and a dihalo aromatic compound are first reacted at 180 to 235 ° C. to a polymerization rate of 50 to 98%, and then water is added to polymerize at a higher temperature. (JP-A-61-7332). However,
In the various methods using the above-mentioned polymerization aids, the amount of the polymer is 0.5 to 2 moles per mole of the alkali metal sulfide, unless the amount is used in a large amount.
Since S cannot be obtained, it is inferior in economic efficiency.
Further, a method using an alkali metal sulfonate, an alkali metal halide and a trialkali phosphate as a polymerization aid is not always effective for obtaining a high molecular weight PAS. On the other hand, after reacting at 180-235 ° C to a polymerization rate of 50-98%,
In the method in which water is added for polymerization, the reaction is carried out at a high temperature in the presence of a large amount of water, so that a high-pressure reactor is required, and there has been a problem that the reactor is severely corroded. Further, there is a problem that a large amount of water and by-product salts are mixed in the reaction solvent recovery system.

[Problems to be solved by the invention]

In view of the above problems of the prior art, the present inventors have conducted intensive studies on a polymerization aid capable of polymerizing a high molecular weight PAS by adding a small amount thereof, and as a result, an amino group-substituted alkali metal salt of an aromatic-substituted aromatic sulfonic acid has been obtained. Was found to be particularly effective, and the present invention was achieved.

[Means for solving the problem]

The production method of the polymer PAS by the present inventors is as follows: a dihalo aromatic compound and (a) an alkali metal sulfide, (b) an alkali metal hydrosulfide and an alkali metal hydroxide, or (c) sulfide in an organic amide solvent. Reacting hydrogen and at least one of alkali metal hydroxides in the presence of at least one compound selected from the group consisting of alkali metal salts of amino group-substituted aromatic sulfonic acids represented by the following formula A: Things.

(In the above formula, R ₁ is an alkyl group having 1 to 12 carbon atoms, n is 0
And an integer M, and M represents an alkali metal selected from lithium, sodium, potassium, rubidium and cesium. Hereinafter, the present invention will be described in more detail.

The organic amide solvent used in the present invention is desirably an aprotic compound.
-Methylcaprolactam, tetramethylurea, N, N-dimethylformamide, N, N-dimethylacetamide, hexamethylphosphoramide, N-methyl-2-pyrrolidone, N-ethylpyrrolidone and the like. -Methyl-2-pyrrolidone is particularly preferred. If necessary, these mixed solvents can be used. The amount of the organic amide solvent to be used is about 100 g to about 1000 g, preferably about 300 g to about 600 g, per mole of the dihalo aromatic compound.

As the (a) alkali metal sulfide used in the present invention, lithium sulfide, potassium sulfide, sodium sulfide, rubidium sulfide, cesium sulfide and the like and a mixture thereof can be used. Instead of or in combination with the alkali metal sulfide, a compound capable of forming an alkali metal sulfide by a reaction, that is, an alkali metal sulfide-forming compound can be used. Specific examples of the alkali metal sulfide-forming compound include (b) a combination of an alkali metal hydrosulfide such as lithium, potassium, sodium, rubidium and cesium with a corresponding hydroxide, and (c) hydrogen sulfide. And alkali metal hydroxides.

Alkali metal sulfides and alkali metal sulfide forming compounds can also be used as hydrates or aqueous mixtures. Among alkali metal sulfides, sodium sulfide is particularly preferable because it is easily available and inexpensive. Sodium sulfide available for industrial use is a water-containing substance having a sodium sulfide content of 60% or 45%, so it is necessary to heat and dehydrate it in an organic amide solvent prior to the reaction. The dehydration is performed by heating the solvent to a temperature close to the boiling point of the solvent in a nitrogen gas stream at normal pressure, and the hydration water of sodium sulfide is preferably reduced to the range of 0.2 to 2.0 mol. If necessary, a small amount of sodium hydroxide can be used in combination to neutralize impurities such as NaHs and Na ₂ S ₂ O ₃ present in these sodium sulfides.

Specific examples of the dihalo aromatic compound used in the present invention include p-dichlorobenzene, m-dichlorobenzene,
5-dichlorotoluene, 1,4-dichloronaphthalene, 1-
Methoxy-2,5-dichlorobenzene, 4,4'-dichlorobiphenyl, 3,5-dichlorobenzoic acid, 2,5-dichloroaniline, 4,4'-dichlorodiphenylsulfone, 4,4'- Dichlorodiphenyl ether and the like. These dihaloaromatic compounds can be used alone or as a mixture of two or more. When two or more dihaloaromatic compounds are used in combination, a copolymer can be obtained. However, when a random copolymer is used, from the viewpoint of maintaining heat resistance, p-
It is preferable that the content of dichlorobenzene is 90 mol% or more. Even in the case of a block copolymer, the content of p-dichlorobenzene is preferably at least 50 mol%.

If necessary, a trihalo aromatic compound or a tetrahalo aromatic compound can be used in combination as a branching agent, and specific examples thereof are 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, trichloronaphthalene, and tetrachloroaromatic compound. Benzene and the like can be mentioned. The amount of the branching agent used is 1 mol% or less, preferably 0.5 mol% or less, based on the dihalo aromatic compound.

-NH ₂ and -SO ₃ M (wherein M is an alkali metal) in one molecule and an amino group-substituted aromatic sulfonic acid alkali metal salt used in the present invention is an aromatic compound having an As specific examples Lithium sulfanilate, potassium sulfanilate, sodium sulfanilate, lithium m-aminobenzenesulfonate, potassium m-aminobenzenesulfonate, sodium m-aminobenzenesulfonate, lithium o-aminobenzenesulfonate, o-aminobenzenesulfonic acid Potassium, sodium o-aminobenzenesulfonate, and the like, but are not limited thereto. Among these, lithium sulfanilate, potassium sulfanilate, and sodium sulfanilate are preferred, and sodium sulfanilate is particularly preferred from the viewpoint of easy availability and low cost. These amino group-substituted aromatic sulfonic acid alkali metal salts may be either anhydrous salts or hydrates, or may be aqueous solutions. Alternatively, the amino group-substituted sulfonic acid and the corresponding alkali metal hydroxide may be separately added and converted into the amino group-substituted sulfonic acid alkali metal salt in the reaction vessel. The amount of the amino group-substituted aromatic sulfonic acid alkali metal salt is in the range of 0.01 to 2.0 in a molar ratio to the alkali metal sulfide,
Preferably it is in the range of 0.1 to 0.5. Thus, the polymerization aid of the present invention has a molar ratio of 0.1 to the alkali metal sulfide.
Use of 01 or more provides an effect of increasing the molecular weight. In this respect, the polymerization aid of the present invention is compared with the fact that the polymerization aid of the prior art cannot be used to obtain a PAS having a high molecular weight as expected by the present invention unless the molar ratio is 1 mol or more. The excellence of is obvious. The timing of addition of the alkali metal salt of an amino group-substituted aromatic sulfonic acid may be added before the dehydration step performed before the reaction, that is, together with the alkali metal sulfide, or after the dehydration step, that is, together with the dihaloaromatic compound. It may be added. When a hydrate or aqueous solution of an amino group-substituted aromatic sulfonic acid alkali metal salt is used, it is preferably added before the dehydration step.

JP-A-55-43139 discloses an invention using an alkali metal salt of an aromatic sulfonic acid having no amino group as a polymerization aid. Although this polymerization aid has a certain effect on increasing the molecular weight of PAS, it has no effect unless it is used in a large amount, and even when used in a large amount, it is possible to obtain PAS having a high molecular weight aimed at by the present invention. Have difficulty. When the alkali metal salt of an aromatic sulfonic acid having an amino group in the present invention is used as a polymerization aid, even a small amount thereof is used.
It is not clear why the degree of polymerization of PAS is remarkably increased, but it is supposed that the effect of suppressing the decomposition reaction of the polymer produced by the reaction during the polymerization reaction of PAS is extremely excellent.

The production method according to the present invention heats and dehydrates a hydrated alkali metal sulfide and an amino group-substituted aromatic sulfonic acid alkali metal salt in an organic amide solvent, and the molar ratio of the alkali metal sulfide to the dihalo aromatic compound is 0.98 to 1.02. And an amount of the dihalo aromatic compound (in some cases, 0.1 to 0.5 mol% of the trihalo aromatic compound may be used in combination with the dihalo aromatic compound). Ten
After reacting at 240 to 260 ° C. for 1 to 10 hours, the mixture is filtered, washed well with water to remove the organic amide solvent and by-product salts, and dried to isolate the polymer.

From the high molecular weight PAS obtained by the production method of the present invention, films and fibers having high elongation can be obtained, and molded articles having extremely high impact strength and bending strength can be obtained.

PAS obtained by the production method of the present invention is also one or more of synthetic resins such as polyetheretherketone, polyethersulfone, polyimide, polyamide, polyphenyleneether, polyarylene, polycarbonate, polyacetal, fluororesin, polystyrene, polyolefin, and ABS. Can be used as a composition mixed with Furthermore, carbon fibers, glass fibers, fibrous fillers such as ceramic fibers, mica, silica powder, alumina powder, talc, titanium oxide powder, calcium carbonate powder, powder such as glass powder, etc. It can also be used as a composition in which at least one kind of filler in the form of a mixture is mixed.

〔Example〕

Hereinafter, examples will be described, but the present invention is not limited to the examples. In the examples,
Analysis of the properties of the polymer was performed by the following method and conditions.

Melt viscosity: Koka type flow tester (CFT-5 manufactured by Shimadzu Corporation)
300 ° C, orifice L / D = 10/1, load 20kg
Is the viscosity measured when the preheating time is 6 minutes.

Weight average molecular weight: Ultra high temperature gel chromatograph (VHT
-GPC).

Example 1 Flake-like sodium sulfide was added to the autoclave of 1.
128.2 g (1 mol, purity 60.82%), sodium sulfanilate dihydrate 23.1 g (0.1 mol) and N-methyl-
Charge 300 g of 2-pyrrolidone and keep the internal temperature at 200
The mixture was heated and stirred until the temperature reached ° C, and dehydrated. 51.8 g of effluent
The content of water was 59% by weight. Further, the loss of hydrogen sulfide during the dehydration step was equivalent to 1.50 mol% in terms of sodium sulfide. After dehydration completion, was cooled to 170 ° C., p-dichlorobenzene 144.8g of (0.985 mol) was added dissolved in N- methyl-2-pyrrolidone 100 g, the reaction system is 1kg with a nitrogen gas / cm ²
-The reaction system was closed by pressurizing to G and reacted at 210 ° C for 7 hours. The temperature was further raised to 250 ° C., and the reaction was carried out at the same temperature for 5 hours. The polymer is separated from the reaction solution by filtration,
After washing once with an aqueous solution of 3% sodium dihydrogen phosphate and once with acetone, 10 times using a vacuum dryer.
Drying at 0 ° C. yielded PAS. The melt viscosity of the obtained PAS is
The weight average molecular weight was 1,840 poise and the weight average molecular weight was 47,000.

Example 2 The amount of sodium sulfanilate dihydrate added was 69.3 g.
(0.3 mol), and the same procedure as in Example 1 was carried out to obtain PAS. The obtained PAS had a melt viscosity of 3,150 poise and a weight average molecular weight of 54,000.

Example 3 PAS was obtained in the same manner as in Example 1 except that 17.9 g (0.1 mol) of lithium o-aminobenzenesulfonate was used instead of dihydrate of sodium sulfanilate. The melt viscosity of the obtained PAS was 1,910 poise, and the weight average molecular weight was 47,000.

Example 4 Flake-like sodium sulfide was added to the autoclave of 1.
128.2 g (1 mol, purity 60.82%), sodium sulfanilate dihydrate 23.1 g (0.1 mol) and N-methyl-
Charge 300 g of 2-pyrrolidone and keep the internal temperature at 200
The mixture was heated and stirred until the temperature reached ° C, and dehydrated. 52.4 g of effluent
The water content was 58% by weight. The loss of hydrogen sulfide during the dehydration step was 1.40 mol% in terms of sodium sulfide. After dehydration completion, was cooled to 170 ° C., p-dichlorobenzene 144.9g of (0.986 mol) was added dissolved in N- methyl-2-pyrrolidone 100 g, the reaction system is 1kg with a nitrogen gas / cm ²
-The reaction system was closed by pressurizing to G, and reacted at 210 ° C for 6 hours. After the reaction was completed, 0.36 g (0.002 mol) of 1,3,5-trichlorobenzene was dissolved in 10 g of N-methylpyrrolidone and added. The temperature was raised to 245 ° C., and the reaction was performed at the same temperature for 5 hours. Thereafter, the same processing as in Example 1 was performed to obtain PAS. The melt viscosity of the obtained PAS was 6,500 poise, and the weight average molecular weight was 60,000.

Comparative Example 1 A PAS was obtained in the same manner as in Example 1 except that no sodium sulfanilate dihydrate was used. The melt viscosity of the obtained PAS was 570 poise, and the weight average molecular weight was 30,000.

Comparative Example 2 A product obtained by performing the same operation as in Example 1 except that 97 g (0.5 mol) of sodium p-toluenesulfonate was used as an alkali metal salt of aromatic sulfonic acid instead of dihydrate of sodium sulfanilate. I got The melt viscosity of the obtained product was 1,100 poise, and the weight average molecular weight was 39,000.

From the above results, the melt viscosity and weight average molecular weight of the PAS obtained when the amino group-substituted aromatic sulfonic acid alkali metal salt was used, when the amino group-substituted aromatic sulfonic acid alkali metal salt was not used, and When the aromatic sulfonic acid alkali metal salt was used, it was found that the solution viscosity and the weight average molecular weight of each of the obtained PAS were higher than those of the PAS.

Claims (2)

(57) [Claims] In an organic amide solvent, a dihalo aromatic compound and (a) an alkali metal sulfide, (b) an alkali metal hydrosulfide and an alkali metal hydroxide, or (c) hydrogen sulfide and an alkali metal hydroxide. A high molecular weight polyarylene sulfide, characterized by reacting at least one of the compounds with an alkali metal salt of an amino group-substituted aromatic sulfonic acid represented by the following formula A in the presence of at least one compound selected from the group consisting of: Production method. (In the above formula, R1 is an alkyl group having 1 to 12 carbon atoms, n is 0
And an integer M, and M represents an alkali metal selected from lithium, sodium, potassium, rubidium and cesium. ) 2. The method according to claim 1, wherein the dihalo-aromatic compound is para-dichlorobenzene and / or meta-dichlorobenzene.