JPS63264633A - Production of polyarylene sulfide - Google Patents

Abstract

PURPOSE:To obtain the title compound having a high melt viscosity, excellent heat stability and low coloration, by polymerizing a heated and dehydrated mixture of a hydration water-containing alkali metal sulfide with an alkali metal hydrosulfide with a dihaloaromatic compound. CONSTITUTION:A hydration water-containing alkali metal sulfide (A) (e.g., sodium sulfide) is mixed with an alkali metal hydrosulfide (B) (e.g., sodium hydrosulfide) in an organic polar solvent (e.g., N-methylpyrrolidone) at a molar ratio of 1:0.005-0.05, and this mixture is heated to 180-230 deg.C and dehydrated until the molar ratio of the alkali metal sulfide to the water is 1:0.5-2.0, and polymerized with 0.9-1.1mol., per mol. of the alkali metal sulfide (C), of a dihaloaromatic compound (e.g., p-dichlorobenzene) at 180-300 deg.C for 0.5-20hr.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing polyarylene sulfide having high melt viscosity and excellent thermal stability.

Furthermore, the present invention relates to a method for producing polyarylene sulfide that provides molded products with little coloring and excellent strength.

Polyarylene sulfide has excellent heat resistance.

Due to its chemical resistance, it is attracting attention as a material for electrical/electronic equipment and automobile equipment. Furthermore, it can be molded into various engineering parts, films, sheets, fibers, etc. by injection molding, extrusion molding, press molding, etc., and is widely used in fields where heat resistance is required.

A typical example of polyarylene sulfide is polyphenylene sulfide (pps).

[Conventional technology]

As a method for producing polyarylene sulfide, Japanese Patent Publication No. 45-5568 discloses a method in which a polyhalogenated aromatic compound and an alkali metal sulfide are reacted in an organic polar solvent such as N-methylpyrrolidone.

That is, prior to polymerization, sulfuric acid containing 9 moles of water of hydration per 1 mole of Na1S) or about 60 to 62 F
Fi% of NamB and approximately 38-40% by weight of water of hydration are heated and dehydrated with nitrogen bubbling in a sodium sulfide N-methylpyrrolidone solvent, and the polymer is reacted with a polyhalogenated aromatic compound. This is the way to get it.

However, because the melt viscosity of the polymer obtained by this method is low, it cannot be used directly for applications such as injection molding.
This low melt viscosity polymer has been used for molding processing by heating and oxidative crosslinking in air, but the polymers and molded products obtained in this way have poor thermal stability, are strongly colored, and The strength was low.

Furthermore, a method for obtaining high molecular weight polyarylene sulfide through a polymerization reaction has been proposed. A typical example is
As disclosed in Japanese Patent Publication No. 52-12240, this is a method in which an alkali metal carboxylate is used as a polymerization aid and the polymerization reaction is carried out in its presence. Since the high molecular weight polymer obtained by Tonoyo 5Kl does not require a heating oxidation crosslinking process, it is thought that the polymer and molded product will have less coloring, but it is difficult to produce an industrial product because it requires the addition of a large amount of alkali metal carboxylate. However, there is a problem in that the cost is significantly high.

[Problem that the invention seeks to solve]

The present invention provides a stable polyarylene sulfide that has a high melt viscosity after polymerization, and even after the polymer is crosslinked by heating and oxidation, it has excellent thermal stability, has little coloring, and provides molded products with excellent strength. , and provides a method for manufacturing it at low cost.

Point [Means for solving the problem] That is, the present invention uses an alkali metal sulfide having an irrigation water and an alkali metal hydrosulfide at a molar ratio of 1:α005 to α05 per K for producing polyarylene sulfide. This is a method for producing polyarylene sulfide, which is characterized by mixing, heating and dehydrating in an organic polar solvent at the same ratio, followed by polymerization with a dihalogenated aromatic compound.

The polyarylene sulfide obtained by the present invention has excellent thermal stability even after being subjected to heat oxidation crosslinking treatment, and molded articles with little coloring and excellent strength can be obtained.

Although the mechanism of action of the present invention is not clear, it is thought that the decomposition reaction of the alkali metal sulfide during dehydration of the alkali metal sulfide containing water of hydration in an organic polar solvent is involved.

That is, when an alkali metal sulfide is dehydrated in an organic polar solvent, hydrogen sulfide and alkali metal hydroxide are generated according to the following formula % (M Ni-alkali metal), and the excess alkali metal hydroxide produced is alkali metal hydroxide. In the polymerization reaction between sulfide and dihalogenated aromatic compound,
This can lead to adverse effects such as side reactions, resulting in poor thermal stability of the resulting polymer. It is believed that because the amount of excess alkali metal hydroxide present afterwards can be reduced and side reactions can be suppressed, a polymer with high melt viscosity and excellent thermal stability can be obtained.

The present invention will be explained in detail below.

Examples of the alkali metal sulfide having water of hydration used in the present invention include lithium sulfide and sodium sulfide.

Includes potassium sulfide and mixtures thereof.

It is also possible to mix an alkali metal hydrosulfide and an alkali metal hydroxide to generate an alkali metal sulfide on the spot.

The amount of hydration water contained in the alkali metal sulfide is not particularly limited, but industrially available alkali metal sulfides usually contain 2 to 1 mole of alkali metal sulfide.
．． It has 6 to 9 moles of water of hydration.

The alkali metal hydrosulfide as used in the present invention includes alkali metal hydrosulfide present as an impurity in the alkali metal sulfide, such as lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, etc. It will be done.

In addition, the amount can be adjusted as appropriate depending on the amount of hydrogen sulfide decomposed and generated during thermal dehydration, and usually less than α005 mol of alkali metal hydrosulfide per 1 mol of alkali metal sulfide is added to the system before dehydration. It is necessary to add it so that it is present in

If the amount of alkali metal hydrosulfide is less than α005 mol, the obtained polymer will have a low melt viscosity and poor thermal stability, so if the polymer obtained by thermal oxidation crosslinking is used to make a molded product, it will be strongly colored. However, the strength is also low, which is not preferable. Further, if more than 105 moles of alkali metal hydrosulfide is present, the yield and melt viscosity of the obtained polymer will decrease, which is not preferable.

The organic polar solvent used in the present invention is preferably an aprotic organic polar solvent that is stable at high temperatures. for example,
N,N-dimethylacetamide, N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone, hexamethylphosphoramide, tetramethylurea, 1,3-dimethyl-
Examples include amides such as 2-imidazolidinone, sulfolanes such as urea, sulfolane, dimethylsulfolane, ketones such as methylphenyl ketone, and mixtures thereof.

Further, the amount used needs to be in the range of 1 to 10 moles per mole of alkali metal sulfide. If it is less than 1 mol, the yield and melt viscosity of the resulting polymer will decrease, which is not preferable. Moreover, when it is more than 10 moles, it is not preferable from an economical point of view.

The dihalogenated aromatic compound used in the present invention has two halogen atoms bonded directly to an aromatic nucleus, such as p-dichlorobenzene, 0-dichlorobenzene m
M-lorbenzene, dibromobenzene, shortbenzene, dichlornaphthalene.

Dibromnaphthalene, short naphthalene, dichlorbiphenyl, dibrombiphenyl, short biphenyl, dichlordiphenyl sulfone.

Cyfurom diphenyl sulfone, SHOD diphenyl sulfone, dichlorobenzophenone, sifurom benzophenone, short benzophenone, dichrome diphenyl ether, dibromidiphenyl ether, dichlordiphenyl sulfide, dibromidiphenyl sulfide, short diphenyl sulfide, etc., and mixtures thereof. are mentioned, but p-dichlorobenzene is usually used.

Furthermore, polyhalogenated aromatic compounds of trihalogen or higher, such as trichlorobenzene, lJ fluorobenzene, triiodobenzene, tetrachlorobenzene, trichlornaphthalene, tetrachloronaphthalene, etc., may be added within a range that does not affect the linearity of the polymer. They can also be used in combination.

The amount of the dihalogenated aromatic compound is usually used in the range of α9 to 1.1 mol per mol of the alkali metal sulfide.

Further, in order to further increase the molecular weight of the polymer, it is also possible to add an auxiliary agent such as an organic alkali metal carboxylate.

In the heating dehydration in the present invention, the internal temperature is usually 180-180°C.
This is done until a temperature range of 230°C is reached. If the internal temperature is lower than 180°, it is not preferable because a large amount of water remains in the system. Further, if the temperature exceeds 230°C, the content of the standard product in the dehydrated solution increases, which is not preferable.

Further, it is usually preferable that the molar ratio of alkali metal sulfide to water after dehydration is in the range of 1:α5 to 2.0.

The polymerization in the present invention is usually carried out at a temperature of 180 to 300°C, preferably 200 to 270°C, with stirring for 15 to 20 hours. If the polymerization temperature is lower than 180° C., the polymerization rate is extremely slow and is not practical.

Furthermore, polymerization at a temperature higher than 300°C is undesirable because decomposition of the polymer occurs.

The polyarylene sulfide can be recovered from the reaction mixture thus obtained by using conventional techniques, for example, after the solvent is recovered by distillation, flashing, etc., the polymer is treated with an organic solvent.

Examples include a method in which the polymer is washed with water and recovered, and a method in which the reaction mixture is filtered to recover the solvent, and then the polymer is washed and recovered.

As a specific example of the polyarylene sulfide obtained by the present invention, polyphenylene sulfide ＠-S → " is mentioned as a typical example, but there are also polyphenylene sulfide sulfone polydiphenylene sulfide ÷ @-@-
Also included are 8→T and copolymers containing two or more of these repeating units.

In addition, the polyarylene sulfide obtained by the present invention can be heat-treated or untreated and used alone or in ceramic fibers such as glass fibers, carbon fibers, and alumina fibers, aramid fibers, wholly aromatic polyester fibers, metal fibers, potassium titanate, etc. reinforcing fillers such as whiskers, calcium carbonate, and mica.

Talc, silica, barium sulfate, calcium sulfate.

Kaolin, clay, pyroferrite, bentonite,
Sericite, zeolite, nephelinsinite, atalpagite, wollastonite.

PM? , 7 elite, calcium silicate, magnesium carbonate, antimony trioxide, zinc oxide, titanium oxide, magnesium oxide, iron oxide, molybdenum disulfide, graphite 9 gypsum, glass peas, glass powder, glass balloon,
It is also possible to mix and use inorganic brighteners such as quartz and organic and inorganic pigments.

In addition, plasticizers, mold release agents, silane-based and titanate-based coupling agents, lubricants, heat-resistant stabilizers, weather-resistant stabilizers, crystal nucleating agents, blowing agents, ion trapping agents, flame retardants, flame retardant aids, etc. It may be added as necessary.

Furthermore, polyethylene, polybutadiene, polyimprene, polychloroprene, polystyrene, polybutene, polyα-methylstyrene, if necessary.

Polyvinyl acetate, polyvinyl chloride, polyacrylic acid ester, polymethac Th ester, polyacrylonitrile, f-ylon 6, nylon 66, f-ylon 610. Nylon 12. Polyamide such as nylon 46, polyester such as polyethylene terephthalate, polybutylene terephthalate, polyarylate, polyurethane, polyacetal, polycarbonate, polyphenylene oxide, polysulfone, polyether sulfone, polyallyl sulfone, polyether ketone, polyether ether ketone,
It is also possible to use a mixture of one or more of homopolymers, random, block, and graft copolymers such as polyimide, polyamideimide, silicone resin, phenoxy resin, and fluororesin.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited only to these Examples.

The melt viscosity of polyarylene sulfide in the following Examples and Comparative Examples was measured using a Koka flow tester (dice:
300℃, 107
Measured with t9 load.

Further, 40% by volume of glass fiber was mixed into the obtained polyarylene sulfide, injection molding was performed, and the color tone of the molded product was visually measured according to A8TM-D790 for bending strength.

Example 1 Internal volume 53 equipped with stirrer, dehydration tower and jacket
In a 0t reactor, 110t of N-methylpyrrolidone, sodium sulfide (purity; Na, S 59.9wtL Na5
H-(Ll 5wt%) 61.7jcp and sodium hydrosulfide (purity + Na5H70Wtl) 4569 were charged and heated with a jacket while stirring to bring the internal temperature to 210
Dehydration was carried out through a dehydration tower until the temperature reached ℃. At this time, 1a4t of a distillate mainly consisting of water and 14.4 moles of H and S were distilled out.

Next, 7 kg of p-dichlorobenzene (LO kg) and 48 t of N-methylpyrrolidone were added, and the
The temperature was raised to 0°C. Since the reaction is an exothermic reaction, in order to avoid a runaway reaction, the heating rate was controlled to be as constant as possible. The reaction was further carried out at 250°C for 3 hours.

At this time, the pressure rose to 90.9/cit.

After the reaction was completed, the reaction mixture was transferred to a solvent recovery vessel equipped with a stirrer, a jacket, and a vacuum line. At this time, N
- Added mer pyrrolidone 35/. Next, 195 t of a distillate mainly consisting of N-methylpyrrolidone was distilled off by heating and stirring under reduced pressure.

Next, 200 tons of water was added to make a water slurry, and the mixture was heated at 80°C.
After heating and stirring for 15 minutes, the polymer was recovered using a centrifuge.

Furthermore, the polymer was returned to the solvent recovery vessel, 200 tons of water was added, and the mixture was heated and stirred at 175°C for 1 hour, and after cooling, the polymer was recovered using a centrifuge.

The polymer was then transferred to a jacketed pump blender and dried under a stream of air until the internal temperature reached 150°C.

A portion of the dried polymer was sampled and its melt viscosity was measured to be 33 Pa-5.

Further, the internal temperature was raised to 250° C., and heating oxidation crosslinking (curing) was performed at 250° C. for 4 hours to obtain 90 PPB in 48.

The melt viscosity of this polymer was 295 Pa·8.

Table 1 shows the molding results obtained by mixing the obtained polymer with glass fiber.

The color of the product was light brown.

Example 2 The same operation as in Example 1 was performed except that the amounts of sodium sulfide and sodium hydrosulfide were changed as shown in Table 1.

The results are shown in Table 1.

Example 3 Sulfide with a high content of sodium hydrosulfide) IJum (
Purity i Na2S 59.1 wt%, NaEIH
The same operation as in Example 1 was performed except that 9 was used for α81 wt%)6')-3 and sodium hydrosulfide was not separately added.

The results are shown in Table 1.

Comparative Example 1 Sulfide used in Example 1) + Jum 6') - 4 to 9
was added and no sodium bisulfide was added. Also,
The curing time was 3 hours.

Comparative Example 2 The amounts of sodium sulfide and sodium hydrosulfide charged were changed as shown in Table 1, and the curing conditions were 255° C. for 5 hours.

The results are shown in Table 1.

Examples 1 to 3 in Table 1. As is clear from the results of Comparative Example 1.2, the polymer melt after polymerization can be reduced by mixing and heating dehydration in the presence of sodium sulfide with adjusted amount of sodium sulfide having water of hydration. It is clear that the viscosity is higher and that the molded articles obtained using the cured polymer have less coloring and are superior in strength.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the polymer has a high melt viscosity after polymerization, has excellent thermal stability even after the polymer is crosslinked by heating and oxidation, and has a molded product with little coloring and excellent strength. It is possible to stably and inexpensively produce polyarylene sulfide that provides

Claims (1)

[Claims] 1) In producing polyarylene sulfide, an alkali metal sulfide having water of hydration and an alkali metal hydrosulfide are mixed in an organic polar solvent at a ratio of 1:0.005 to 0.05 (molar ratio), A method for producing polyarylene sulfide, which comprises heating and dehydrating the product and then polymerizing it with a dihalogenated aromatic compound.