JPH0674327B2 - Method for producing polyarylene sulfide - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a polyarylene sulfide used as an electric material, an electronic material, a coating agent, an additive for molded articles and the like.

[Prior Art and Problems to be Solved by the Invention] Conventionally, polyarylene sulfides such as polyphenylene sulfides contain dihalogenated aromatic compounds such as p-dichlorobenzene and alkali metal sulfides such as sodium sulfide and N- It is produced by a polycondensation reaction under a high temperature and pressure in a polar solvent such as methylpyrrolidone (see Japanese Patent Publication No. 45-3368).

However, in the method described in this patent publication, the polymerization is performed at 125
Since it needs to be performed at a high temperature of ~ 450 ° C and under a pressure of 1000 psig or more, it consumes a lot of energy, and the by-produced alkali metal salt remains in the polyarylene sulfide. There were problems such as making it worse.

Further, a method of directly obtaining a polyarylene sulfide by polymerizing diphenyl disulfide or thiophenol using sulfuric acid as a catalyst is also known, but it has many drawbacks such as a large amount of by-products and a large amount of crosslinked polymer. .

Another method for obtaining polyarylene sulfide by using diphenyl disulfide or thiophenol is disclosed in JP-A-63-2135.
Although disclosed in No. 26 and No. 63-213527,
There is a problem in that expensive Lewis acids and oxidizing agents must be used in large amounts (equimolar amounts), and a large amount of solvent or detergent is required to remove these Lewis acids and the like remaining in the polymer.

Further, in Macromol 22 , 4138 (1989), diphenyl disulfides are oxidatively coupled and polymerized in the atmosphere in the presence of an acid and a catalyst, so that they have no electrical properties such as alkali metal salts and other electrical characteristics. A substantially linear polyarylene sulfide having excellent chemical properties, in particular, a by-product of a cross-linked polymer, is obtained, and in this case, not only the reaction rate is slow, but also the molecular weight of the obtained polymer is It has the drawback of being low.

Therefore, an object of the present invention is to provide a method for producing a polyarylene sulfide having a high molecular weight and being substantially straight-chained with good productivity under mild conditions with good productivity. To provide.

[Means for Solving the Problems] The inventors of the present invention have conducted extensive studies in order to achieve the above object, and as a result, use diphenyl disulfide and / or thiophenol as a reaction raw material, which is used in the presence of an acid as a catalyst. When producing a polyarylene sulfide by oxidative coupling polymerization using, the polymerization reaction is carried out in two steps, and the polymer or polymer-containing substance is separated from the reaction mixture obtained in the first step polymerization reaction, It was found that the method of carrying out the second-stage polymerization reaction using the obtained polymer or polymer-containing substance is extremely effective in achieving the object of the present invention, and the present invention is based on this finding. It came to completion.

That is, the present invention has the general formula [I] (In the formula [I], R ^{1 to} R ⁸ each represent a hydrogen atom, a halogen atom, a lower alkyl group or a lower alkoxy group,
R ^{1 to} R ⁸ may be the same kind or different kinds. ) Diphenyl disulfides and / or general formula [II] (In the formula [II], R ^{9 to} R ¹² each represent a hydrogen atom, a halogen atom, a lower alkyl group or a lower alkoxy group, and R ^{9 to} R ¹² are the same kind or different kinds. When a polyarylene sulfide is produced by oxidative coupling polymerization of a thiophenol represented by the formula (1) in the presence of an acid, a polymerization reaction is carried out in two steps, and a polymerization in the first step is carried out. Production of a polyarylene sulfide, characterized in that a polymer or a polymer-containing substance is separated from the reaction mixture obtained by the reaction, and the obtained polymer or polymer-containing substance is used for a second-stage polymerization reaction. It is based on the law.

Since the present invention is an invention of a so-called product manufacturing method, the present invention will be described below in the order of (A) starting material (monomer), (B) processing condition (polymerization condition), (C) target material (polymer). Will be described in detail.

(A) Starting Material (Monomer) The monomer used as a starting material in the method for producing a polyarylene sulfide of the present invention is represented by the diphenyl disulfides represented by the general formula [I] and / or the general formula [II]. Thiophenols.

R ^{1 to} R ¹² in the general formulas [I] and [II] will be described in more detail below.

That is, when exemplifying each specific example of R ^{1 to} R ¹² , for example, a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom; a methyl group, an ethyl group, a propyl group, and 1-methyl. Ethyl group, butyl group, 1-
Methylpropyl group, 2-methylpropyl group, 1,1-dimethylethyl group, pentyl group, hexyl group, heptyl group,
Lower alkyl group such as octyl group; methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group,
Examples thereof include lower alkoxy groups such as isobutoxy group, sec-butoxy group, tert-butoxy group, pentyloxy group and hexyloxy group. Among these, a hydrogen atom; a methyl group, an ethyl group; a methoxy group and an ethoxy group are preferable, and a hydrogen atom, a methyl group, an ethyl group and the like are particularly preferable.

Examples of the diphenyl disulfides represented by the general formula [I] include diphenyl disulfide, 2,
2'-dimethyldiphenyl disulfide, 3,3'-dimethyldiphenyl disulfide, 2,2 ', 6,6'-tetramethyldiphenyl disulfide, 2,2', 3,3'-tetramethyldiphenyl disulfide, 2,2 ' , 5,5'-tetramethyldiphenyl disulfide, 3,3 ', 5,5'-tetramethyldiphenyl disulfide, 2,2', 3,3 ', 5,5'-hexamethyldiphenyl disulfide, 2,2' , 3,3 ′, 6,6 ′
-Hexamethyldiphenyl disulfide, 2,2 ', 3,3',
5,5'6,6'-octamethyldiphenyl disulfide, 2,
2'-diethyldiphenyldisulfide, 3,3'-diethyldiphenyldisulfide, 2,2'6,6'-tetraethyldiphenyldisulfide, 2,2'3,3'6,6'-hexaethyldiphenyldisulfide, 2,2 ′, 3,3 ′, 5,5′6,6 ′
-Octaethyldiphenyldisulfide, 2,2'-dipropyldiphenyldisulfide, 3,3'-dipropyldiphenyldisulfide, 2,2'5,5'-tetrapropyldiphenyldisulfide, 2,2'-dibutyldiphenyldisulfide, 2 2,2'-dipentyldiphenyl disulfide, 2,2'-dihexyl diphenyl disulfide, 2,2 '
-Difluorodiphenyl disulfide, 2,2'-dichlorodiphenyl disulfide, 2,2'-dibromodiphenyl disulfide, 2,2'-diiododiphenyl disulfide, 3,3'-difluorodiphenyl disulfide, 3,
3'-dichlorodiphenyl disulfide, 3,3'-dibromodiphenyl disulfide, 3,3'-diiododiphenyl disulfide, 2,2'3,3'-tetrafluorodiphenyl disulfide, 2,2'3,3'-tetra Chlorodiphenyl disulfide, 2,2'5,5'-tetrafluorodiphenyl disulfide, 2,2'5,5'-tetrachlorodiphenyl disulfide, 2,2'6,6'-tetrafluorodiphenyl disulfide, 2,2 '6,6'-Tetrachlorodiphenyl disulfide, 2,2'6,6'-Tetrabromodiphenyl disulfide, 3,3'5,5'-Tetrafluorodiphenyl disulfide, 3,3'5,5'-Tetrachlorodiphenyl Disulfide, 2,2'3,3'5,5'-hexafluorodiphenyl disulfide, 2,2'3,3'5,5'-hexachlorodiphenyl disulfide, 2,2'3,3'6,6'- Hexafluorodi Phenyl disulfide, 2,2'3,3'6,6'-hexachlorodiphenyl disulfide, 2,2'3,3'5,5'6,6'-octafluorodiphenyl disulfide, 2,2'3,3 ' Five,
5'6,6'-octachlorodiphenyl disulfide, 2,
2'-dimethoxydiphenyl disulfide, 2,2'-diethoxydiphenyl disulfide, 2,2'-diisopropoxydiphenyl disulfide, 2,2'-dipropoxydiphenyl disulfide, 2,2'-dibutoxydiphenyl disulfide, 2, 2'3,3'-tetramethoxydiphenyl disulfide, 2,2'6,6'-tetramethoxydiphenyl disulfide, 2,2'6,6'-tetraethoxydiphenyl disulfide, 3,3'-dimethoxydiphenyl disulfide, 2 Symmetrical diphenyl disulfides such as 2,2'5,5'-tetramethoxydiphenyl disulfide; 2-methyldiphenyl disulfide, 2-ethyldiphenyl disulfide, 2-propyldiphenyl disulfide, 2-butyldiphenyl disulfide, 2-fluorodiphenyl disulfide, 2- Chlorodiphenyldis Fido, 2-methoxy diphenyl disulfide, 2,6-dimethyl diphenyl disulfide, 2,6-diethyl diphenyl disulfide, 2,6-difluoro diphenyl disulfide, 2,3
Dimethyldiphenyldisulfide, 2,3,5,6-tetrafluorodiphenyldisulfide, 2,3,5,6-tetramethyldiphenyldisulfide, 2,3,6-trimethyldiphenyldisulfide, 2,6-dimethyl-2'-methyl Diphenyl disulfide, 2,6-dimethyl-2'-ethyldiphenyl disulfide, 2,6-dimethyl-2 ', 3', 5 ',
6'-tetrafluorodiphenyl disulfide, 2,6-dimethyl-2'-methoxydiphenyl disulfide, 2,6
-Diethyl-2'-methyldiphenyl disulfide, 2,
6-diethyl-2'-ethyldiphenyl disulfide,
2,6-Diethyl-2,3,5,6-tetrafluorodiphenyl disulfide, 2,6-dimethyl-2 ', 6'-diethyldiphenyl disulfide, 2,6-dimethyl-2', 6'-difluorodiphenyl disulfide , 2,3,5,6-tetramethyl-2 ', 3', 5 ', 6'-tetrafluorodiphenyl disulfide and other asymmetric diphenyl disulfides. Among these, diphenyl disulfide, 3,3 ', 5,5'-tetramethyldiphenyl disulfide, 2,2', 6,6'-tetramethyldiphenyl disulfide, 2,2'-dimethyldiphenyl disulfide,
3,3'-dimethyldiphenyl disulfide, 2,2 ', 5,5'
-Tetramethyldiphenyl disulfide and the like are preferred.

Examples of the thiophenols represented by the general formula [II] include thiophenol, 2-methylthiophenol, 2-ethylthiophenol, 2-propylthiophenol, 2- (1-methylethyl) thiophenol, 2
-Butylthiophenol, 2- (1-methylpropyl)
Thiophenol, 2- (2-methylbutyl) thiophenol, 2- (1,1-dimethylethyl) thiophenol,
2-pentylthiophenol, 2-hexylthiophenol, 2-octylthiophenol, 2-fluorothiophenol, 2-chlorothiophenol, 2-bromothiophenol, 2-iodothiophenol, 2-methoxythiophenol, 2- Ethoxythiophenol, 2-
Propoxythiophenol, 2-butoxythiophenol, 2-sec-butoxythiophenol, 2-isobutoxythiophenol, 2-tert-butoxythiophenol, 2-pentyloxythiophenol, 2-hexyloxythiophenol, 2-dimethyl Thiophenol,
2,6-diethylthiophenol, 2-methyl-6-ethylthiophenol, 2,6-difluorothiophenol,
2-methyl-6-fluorothiophenol, 2-ethyl-6-fluorothiophenol, 2,6-dibromothiophenol, 2-methyl-6-chlorothiophenol, 2,
6-dimethoxythiophenol, 2-methyl-6-methoxythiophenol, 2,3-dimethylthiophenol,
2,3-diethylthiophenol, 2,3-difluorothiophenol, 2-methyl-3-fluorothiophenol,
2-fluoro-3-methylthiophenol, 2,3-dimethoxythiophenol, 2-methyl-3-methoxythiophenol, 2,3-dichlorothiophenol, 2-methyl-3-chlorothiophenol, 3-chloro-2 -Methylthiophenol, 2,5-dimethylthiophenol, 2,5
-Difluorothiophenol, 2,5-diethylthiophenol, 2-methyl-5-fluorothiophenol, 2
-Methyl-5-ethylthiophenol, 2-fluoro-
5-methylthiophenol, 2,5-dichlorothiophenol, 2,5-dimethoxythiophenol, 2-methyl-
5-chlorothiophenol, 2-methyl-5-methoxythiophenol, 2-chloro-5-methylthiophenol, 2-methoxy-5-methylthiophenol, 2-chloro-5-fluorothiophenol, 2-ethyl-5-
Chlorothiophenol, 2-chloro-5-ethylthiophenol, 3,5-dimethylthiophenol, 3,5-difluorothiophenol, 3,5-dimethoxythiophenol, 3,5-diethylthiophenol, 3,5- Dichlorothiophenol, 3-methyl-5-fluorothiophenol, 3-methyl-5-chlorothiophenol, 3-methyl-5-methoxythiophenol, 2,3,5-trimethylthiophenol, 2,3,5- Trifluorothiophenol, 2,3,5-triethylthiophenol, 2,3,5-trichlorothiophenol, 2-methyl-3,5-difluorothiophenol, 2,3,5,6-tetramethylthiophenol, 2 , 3,5,6-Tetrafluorothiophenol, 2,3,5,6
-Tetrachlorothiophenol, 2,3,5,6-tetramethoxythiophenol, 2,3,5,6-tetraethylthiophenol, 2,6-dimethyl-3,5-difluorothiophenol, 2,6-diethyl -3,5-difluorothiophenol,
2,6-diethyl-3,5-dichlorothiophenol, 2,6-
Diethyl-3,5-dimethylthiophenol, 2,6-diethyl-3,5-dimethoxythiophenol, 2,6-dimethyl-
Examples thereof include 3,5-dichlorothiophenol and 2-methyl-6-ethyl-3,5-difluorothiophenol.

Among these, in particular, thiophenol, 2-methylphenol, 2-ethylthiophenol, 2-methoxythiophenol, 2,5-dimethylthiophenol, 3,5-dimethylthiophenol, 2,5-diethylthiophenol,
Preferred are 3,5-diethylthiophenol, 2,6-dimethylthiophenol, 2,6-diethylthiophenol, 2,6-dimethoxythiophenol and 2,3,5,6-tetramethylthiophenol.

(B) Treatment Conditions (Polymerization Conditions) In the method for producing a polyarylene sulfide of the present invention, the diphenyldisulfides of the general formula [I] and / or the thiophenols of the general formula [II] are added in the presence of an acid. Oxidative coupling polymerization is carried out using a catalyst.

In this oxidative coupling polymerization, the presence of an acid is essential, and examples of such an acid include a proton acid or a proton acid donor that changes into a proton acid by the coexistence of a proton donating substance. Its salt,
Inorganic acids or salts thereof, as well as mixtures or complexes thereof can be used. As the protic acid, for example, non-oxygen acids such as hydrochloric acid, hydrobromic acid, and hydrocyanic acid;
Sulfuric acid, phosphoric acid, chloric acid, bromic acid, nitric acid, carbonic acid, boric acid,
Inorganic oxo acids such as molybdic acid, isopoly acid and heteropoly acid; monovalent or polyvalent carboxylic acids such as acetic acid, propionic acid, butanoic acid, succinic acid, benzoic acid and phthalic acid; monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, Halogen-substituted carboxylic acids such as monofluoroacetic acid, difluoroacetic acid, trifluoroacetic acid; methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid Examples thereof include monovalent or polyvalent sulfonic acids such as trifluoromethanesulfonic acid and benzenedisulfonic acid.

Among these, non-volatile and highly stable strong acidic protic acids such as sulfuric acid, trifluoroacetic acid and trifluoromethanesulfonic acid are preferable, and trifluoroacetic acid is particularly preferable.

These protic acids may be used alone or in combination of two or more.

It is considered that these protonic acids have a catalytic action on the oxidative coupling polymerization together with the catalyst described in detail later.

The amount of the above-mentioned protonic acid added to the starting material (monomer) varies depending on the type of the protonic acid, the presence / absence of combined use with a protonic acid donor, the type of the starting material (monomer), other polymerization conditions, etc., and is appropriately determined. However, the amount of the above-mentioned protonic acid is preferably 0.001 to 15 times the number of moles of the starting material. The reason is that if it is less than 0.001 times, the catalytic action on the oxidative coupling polymerization is small, and if it exceeds 15 times, the reaction efficiency of the starting material (monomer) is lowered.

Examples of the proton acid donor include anhydrous acids such as acetic anhydride, trifluoroacetic anhydride, and trifluoromethanesulfonic anhydride; sodium hydrogen sulfate, sodium dihydrogen phosphate, proton residual heteropolyacid salt, monomethyl sulfuric acid, trifluoromethyl sulfuric acid, etc. Partial salts or partial esters of sulfuric acid; compounds capable of acting as a protonic acid by dissolving or decomposing in a solvent, such as ammonium chloride, ammonium phosphate, ammonium sulfate, and ammonium heteropolyate; Partial metal salts of divalent sulfonic acid can be mentioned. It is considered that these protonic acid donors are converted into a protonic acid in the reaction system and have a catalytic action on the oxidative coupling polymerization together with the catalyst described in detail later.

The amount of the above-mentioned protonic acid donor added to the starting material (monomer) varies depending on the type of the protonic acid donor, the presence / absence of combined use with a protonic acid, the type of the starting material (monomer), other polymerization conditions, etc. However, the amount of the above proton acid donor is 0.001 to 1 with respect to the number of moles of the starting material.
It is preferably 5 times. The reason is that if it is less than 0.001 times, the catalytic action for oxidative coupling polymerization is small,
On the other hand, if it exceeds 15 times, the reaction efficiency of the starting material (monomer) will decrease.

Of these protonic acid donors, it is particularly preferred to use anhydrous acids. The reason is that these anhydrides have a function of removing H ₂ O (by-product) which is a by-product as the oxidative coupling polymerization progresses, and then the protonic acid generated after the incorporation of H ₂ O causes oxidation of the oxidation cup. This is because it exerts a catalytic action on ring polymerization. It is particularly preferable that the amount of the anhydrous acid that fulfills these two functions is 1 to 10 times the number of moles of the starting material (monomer). The reason is that if the amount is less than 1 time, the dehydration action and the catalytic action are not sufficient, while if it exceeds 10 times,
This is because it is uneconomical to expect further dehydration and catalytic action.

When focusing only on the removal of H ₂ O by-produced in the oxidative coupling polymerization, a dehydrating agent such as anhydrous sodium sulfate or calcium chloride that does not affect the polymerization reaction may be used. Therefore, the use of the above-mentioned protonic acid and / or protonic acid donor is naturally essential.

The catalyst used in the method for producing a polyarylene sulfide of the present invention is preferably a vanadium catalyst,
For example, vanadyl acetylacetonate (VO (aca
c) ₂ ), vanadyl tetraphenylporphyrin (VOTP
P), vanadium trichloride oxide, vanadium acetylacetonate, vanadium porphyrin and other vanadium compounds. These vanadium-based catalysts are
They may be used alone or in combination of two or more. The amount of this vanadium-based catalyst is preferably 0.0001 to 5 mol per 1 mol of the starting material (monomer). The reason is that if it is less than 0.0001 mol, the polymerization rate will be slow, while if it exceeds 5 mol, the catalyst cost will be high and the operation of removing the catalyst from the produced polymer will be complicated. A particularly preferred amount of vanadium catalyst used is 0.0005 to 1 mol per 1 mol of the starting material (monomer). The catalyst used in the method for producing the polyarylene sulfide of the present invention plays a role of oxygen transport and promotes oxidative coupling polymerization.

Although it has been described that the presence of an acid and the use of a catalyst are essential conditions, the following important essential conditions are present in the method of the present invention. That is, the polymerization reaction is carried out in two steps, the polymer or the polymer-containing substance is separated from the reaction mixture obtained in the first step, and the polymer or the polymer-containing substance is used in the second step. Is carried out to obtain a substantially linear polyarylene sulfide having a high molecular weight.

This two-step polymerization reaction in the method for producing polyarylene sulfide of the present invention will be described in detail below.

First, the polymerization reaction in the first step is carried out in the presence of the above-mentioned acid using the above-mentioned catalyst in the air, under an atmospheric oxygen atmosphere, under oxygen blowing or under oxygen pressurization. In order to increase the reaction rate, it is preferable to carry out the polymerization under an oxygen atmosphere, particularly under an oxygen blowing or under an oxygen pressure.

The first-stage polymerization reaction can be carried out in the absence of a solvent (bulk polymerization), but it is usually desirable to carry out in the presence of a solvent. As this solvent, any solvent can be used as long as it does not substantially lose the polymerization activity, but it is preferable to use a solvent capable of dissolving the starting material (monomer), acid and the like. Usually, as a solvent that can be preferably used, for example, nitromethane, methylene chloride, dibromoethane, tetrachloroethane, nitrobenzene and the like can be mentioned. In addition to these, solvents generally used for Friedel-Crafts reaction, cationic polymerization, etc. Can also be appropriately selected and used suitably.

In the first stage polymerization reaction, these solvents may be used alone or in combination of two or more, or if necessary, for example, aromatic hydrocarbons such as benzene, toluene, etc. You may use it, mixing an inert solvent etc. suitably.

The reaction temperature in the first stage polymerization reaction can be appropriately selected within the range of -5 to 150 ° C. A preferable temperature is 0 to 40 ° C., and a particularly preferable temperature is room temperature or its vicinity.

The reaction time in the first stage polymerization reaction varies depending on the desired molecular weight of the polymer obtained in the first stage polymerization reaction and the like, but is usually in the range of 0.2 to 100 hours, particularly preferably
The range of 0.5 to 50 hours is adopted.

The polymerization system in the first-stage polymerization reaction is not particularly limited, and any of continuous system, semi-continuous system and batch system may be used. When using the batch system, it is desirable to stir the reaction system.

Next, the polymer or the polymer-containing substance is separated from the reaction mixture obtained in the first stage polymerization reaction. The former polymer separation is carried out, for example, by introducing the above reaction mixture into a precipitant. As the precipitating agent, any liquid can be used as long as it can precipitate the polymer when the reaction mixture is added, but it is particularly preferable to use methanol, more preferably methanol containing hydrochloric acid. The latter separation of the polymer-containing substance is carried out by evaporating a volatile component (for example, a solvent, an unreacted monomer, etc.) from the reaction mixture obtained in the first stage polymerization reaction under normal pressure or reduced pressure. Prior to or during the evaporation operation, a solvent (for example, benzene, dioxane, etc.) that forms an azeotrope with water or the like contained in the reaction mixture is added to the reaction mixture, so that the evaporation operation can be performed efficiently. Is convenient. The separated polymer-containing substance contains a non-volatile component (for example, a catalyst) in addition to the polymer.

The reaction mixture obtained by the polymerization reaction in the first step was put into a precipitating agent to precipitate a polymer, and then the polymer was filtered off to obtain a low polymer such as an oligomer or a telomer from a filtrate obtained. These low polymers may be separated and subjected to the subsequent second stage polymerization reaction.

Then, the polymer or polymer-containing substance separated after the first-stage polymerization reaction is used to carry out the second-stage polymerization reaction. This second-stage polymerization reaction is also carried out in the presence of the above-mentioned acid in the atmosphere using the above-mentioned catalyst in the same manner as in the first-stage polymerization reaction.
It is carried out under an atmospheric pressure oxygen atmosphere, under oxygen blowing or under oxygen pressure. As in the case of the first stage polymerization reaction, in order to increase the reaction rate, it is preferable to carry out the polymerization under an oxygen atmosphere, particularly under an oxygen blowing or under an oxygen pressure.

In the second-stage polymerization reaction, the polymer or the polymer-containing substance obtained in the first-stage polymerization reaction may be added with a predetermined amount of the same or different type of monomer as the monomer constituting the polymer. In the polymerization reaction of the second stage, by adding a predetermined amount of this monomer, it is possible to obtain the advantages that the reaction efficiency can be increased and a block type copolymer can be obtained.

The second-stage polymerization reaction can also be carried out in the absence of a solvent (bulk polymerization), but it is usually preferable to carry out in the presence of a solvent, and suitable solvents are those used in the first-stage polymerization reaction. Is mentioned.

The reaction temperature in the second stage polymerization reaction can be appropriately selected within the range of -5 to 150 ° C. A preferable temperature is 0 to 80 ° C., and a particularly preferable temperature is room temperature or its vicinity.

The reaction time in the second-stage polymerization reaction varies depending on the desired molecular weight of the polymer finally obtained, etc.,
Usually, a range of 0.2 to 100 hours is used, and a range of 0.5 to 50 hours is particularly preferable.

The polymerization system in the second-stage polymerization reaction is not particularly limited, and any of continuous system, semi-continuous system and batch system may be used. When using the batch system, it is desirable to stir the reaction system.

Since the operation of obtaining the target substance (polymer) by the post-treatment after the second-stage polymerization reaction is performed by a known technique, its description is omitted here.

(C) Target substance (polymer) The starting material (diphenyl disulfides of general formula [I] and / or thiophenols of general formula [II]) described in (A) above is polymerized as described in (B) above. By subjecting the compound to oxidative coupling under the conditions, the compound of general formula [III] can be obtained as the target substance (polymer). (However, R ^{13 to} R ¹⁶ in the formula [III] have the same meaning as R ^{1 to} R ¹² in the general formulas [I] and [II], respectively). Sulfides, especially linear polyarylene sulfides having a significantly low degree of crosslinking, are obtained.

According to the method for producing a polyarylene sulfide of the present invention, after separating the polymer or the polymer-containing substance obtained in the polymerization reaction in the first step from the reaction mixture, the polymer or the polymer-containing substance obtained is used to By performing the two-step polymerization reaction, the logarithmic viscosity η _{inh is} higher than that of the polyarylene sulfide obtained by the conventional method which does not perform the two-step polymerization reaction.
Is extremely high, and a high molecular weight polyarylene sulfide is obtained.

When a single substance is used as a starting material monomer, a homopolymer (homopolymer) is obtained, and when two or more kinds of copolymerizable monomers are used, a copolymer (copolymer) is used. Is obtained. Even when two or more kinds of monomers are used, a mixture of homopolymers (homopolymers) can be obtained when these monomers are not copolymerized.

The obtained polyarylene sulfide has excellent chemical properties such as heat resistance and chemical resistance, and in particular, since it does not contain a salt that deteriorates the insulating property such as an alkali metal salt, which has been a problem in the past, it has remarkably excellent electrical properties. Are better. Therefore, it can be suitably used as a device, a part, a material, etc. in various fields such as the fields of electronics, electricity, machines, and paints.

[Examples] The present invention is further described below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 The first stage polymerization reaction was carried out as follows. That is, in the air, 2,2 ', 6,6'-tetramethyldiphenyl disulfide 8.03 g, trifluoromethanesulfonic acid 0.227 g
g, 13.0 g of trifluoroacetic anhydride and 0.391 g of vanadyl acetylacetonate (hereinafter referred to as VO (acac) ₂ ) were dissolved in 280 ml of methylene chloride and reacted at room temperature for 20 hours. After a predetermined time, 3.6 l of methanol containing 2 ml of concentrated hydrochloric acid was added to the reaction mixture to precipitate a precipitate, which was filtered through a glass filter and dried to obtain 3.15 g of a polymer (yield 39%).

A part of the polymer is taken and the logarithmic viscosity is 0.
As a result of measurement at a concentration of 5 g / dl and 30 ° C., η _inh = 0.020 dl / g. In addition, the amount of residual monomer was quantified by gas chromatography using sulfolane as the internal standard substance, and it was found that the residual monomer content was 4.08%.

Next, the second stage polymerization reaction was carried out as follows. That is, 3.00 g of the above polymer was taken, and 0.17 g of trifluoromethanesulfonic acid, 5.54 g of trifluoroacetic anhydride and 0.14 g of VO (acac) ₂ were added thereto in 70 ml of methylene chloride to obtain an oxygen pressure of 2.9 k.
The reaction was carried out at 20 ° C. for 43 hours under g / cm ² -G. afterwards,
The amount of the polymer precipitated and recovered in 600 ml of methanol containing 1 ml of concentrated hydrochloric acid was 2.95 g (yield 98% as the second stage polymerization reaction), and its η _inh was 0.047 dl / g. It was
No residual monomer was found.

Thus, it was confirmed that the polymer obtained in Example 1 had a high viscosity and a high molecular weight. It was also confirmed that no residual monomer was present.

Comparative Example 1 The reaction was carried out in the same manner as in the first stage polymerization reaction of Example 1 except that the reaction time was 70 hours (unlike Example 1, the second stage polymerization reaction was not performed).

The reaction mixture obtained after the reaction was treated in the same manner as in Example 1 to obtain 4.65 g of a polymer (yield 57.9%). It was confirmed that the obtained polymer had a low viscosity of η _inh of 0.020 dl / g and a low molecular weight. It was also confirmed that 3.3% of residual monomer was present.

Comparative Example 2 2,2 ', 6,6'-Tetramethyldiphenyldisulfide 3.0
The polymerization reaction was carried out in the same manner as in the second stage polymerization reaction of Example 1 except that 0 g was used and the reaction time was 65 hours (unlike Example 1, the first stage polymerization reaction was carried out). There was not).

The reaction mixture obtained after the reaction was treated in the same manner as in Example 1 to obtain 2.61 g of a polymer (yield 87.1%). It was confirmed that the obtained polymer had a low viscosity of η _inh of 0.038 dl / g and a low molecular weight. It was also confirmed that 1.4% of residual monomer was present.

Example 2 The first stage polymerization reaction was carried out as follows. That is, 2,2 ', 6,6'-tetramethyldiphenyl disulfide 3.00 g, trifluoromethanesulfonic acid 0.17 g, trifluoroacetic acid 4.58 g and VO (acac) ₂ 0.26 g were dissolved in methylene chloride 100 ml and sealed. The reaction was performed by stirring in an eggplant-shaped flask at room temperature for 16 hours. After a lapse of a predetermined time, 100 ml of benzene was added to the reaction mixture and the mixture was evaporated by a rotary evaporator for 10 minutes to remove volatile components to obtain a viscous liquid polymer-containing substance. When a part of this substance was taken and quantified by gas chromatography, trifluoroacetic acid and trifluoroacetic anhydride were not contained.

Next, the second stage polymerization reaction was carried out as follows. That is, 100 ml of methylene chloride and 4.83 g of trifluoroacetic anhydride were added to the above-mentioned polymer-containing substance, which was dissolved again at room temperature for 2 minutes.
The reaction was carried out for 6 hours. The obtained reaction mixture was treated by a conventional method to obtain 1.22 g of a polymer (yield 41%). Η _inh of the obtained polymer was 0.025 dl / g, which is different from Example 2 in that the benzene addition-evaporation step was performed between the first stage polymerization reaction and the second stage polymerization reaction. It was revealed that the value was higher than η _{inh of} the polymer obtained in Comparative Example 3 described later, which was not used.

Comparative Example 3 As described above, the same method as in Example 2 (polymerization time 42 hours) was performed except that the benzene addition-evaporation step was not performed between the first-stage polymerization reaction and the second-stage polymerization reaction. It was carried out to obtain 1.21 g of polymer (yield 40%). The η _inh of the obtained polymer was 0.020 dl / g, which was lower than the η _{inh of} the polymer obtained in Example 2 as described above.

Example 3 The first stage polymerization reaction was carried out as follows. That is, 2,2 ′, 6,6′-tetramethyldiphenyl disulfide 8.98 g, trifluoromethanesulfonic acid 0.51 g, trifluoroacetic anhydride 19.4 g, and VO (acac) ₂ 0.767 g are dissolved in methylene chloride 85 ml, and oxygen is dissolved. The reaction was carried out at 5 ° C. for 20 hours under a gas flow rate of 35 ml / min.

The obtained reaction mixture was treated by a conventional method to give a polymer 6.38 g.
(Yield 71%) was obtained. Η _inh of the obtained polymer is 0.024 dl
/ g, the residual monomer was 3.5%.

Next, the second stage polymerization reaction was carried out as follows. That is, 2.02 g of the above polymer was added with 2,2 ′, 6,6 ′ as a monomer.
After adding 0.21 g of tetramethyldiphenyl disulfide to obtain a mixed liquid of a polymer and a monomer, this mixed liquid contains 0.08 g of trifluoromethanesulfonic acid, 4.23 g of trifluoroacetic anhydride and 0.14 g of VO (acac) ₂ 5 ° C while blowing oxygen into methylene chloride at a flow rate of 35 ml / min
And reacted for 42 hours. The obtained reaction mixture was treated by a conventional method to obtain 1.78 g of a polymer (yield 79%). It was confirmed that the obtained polymer had a high η _inh of 0.048 dl / g and a high molecular weight. No residual monomer was detected.

Example 4 The first stage polymerization reaction was carried out as follows. That is, the reaction mixture obtained by carrying out in the same manner as the polymerization reaction in the first step of Example 1 was added to methanol containing concentrated hydrochloric acid, and the deposited precipitate was separated by filtration to obtain a viscous solid. After concentrating until it becomes redissolved in methylene chloride,
Washing with water, washing with alkali, and washing with water were carried out in order to collect a methanol-soluble oligomer. The collected oligomers are 2,2 ',
It was a low polymer of 6,6'-tetramethyldiphenyl disulfide and contained 35.4% of residual monomers.

Next, the second stage polymerization reaction was carried out as follows. That is, 3.36 g of the above oligomer, 0.16 g of trifluoromethanesulfonic acid, 5.00 g of trifluoroacetic anhydride and VO (aca
c) ₂ 0.20 g was mixed in methylene chloride, stirred, and reacted for 42 hours at room temperature in an oxygen atmosphere. After a predetermined time, the reaction mixture was poured into methanol to precipitate the polymer.
2.16 g (yield 64%) was obtained. Η _inh of the obtained polymer is 0.
It is 024 dl / g, and by carrying out the second stage polymerization reaction, a polymer having a remarkably high molecular weight as compared with the raw material oligomer can be obtained. The amount of residual monomer in the obtained polymer was 2.1%, which was significantly smaller than the amount of residual monomer (35.4%) in the raw material oligomer.

EFFECTS OF THE INVENTION According to the present invention, a substantially linear polyarylene sulfide having a high molecular weight can be obtained with good productivity under mild conditions. Since the obtained polyarylene sulfide does not contain impurities such as alkali metal salts, it has excellent electrical properties, chemical properties, etc., and is suitably used for electrical and electronic materials.

Claims (3)

[Claims] 1. A general formula [I] (In the formula [I], R ^{1 to} R ⁸ each represent a hydrogen atom, a halogen atom, a lower alkyl group or a lower alkoxy group,
R ^{1 to} R ⁸ may be the same kind or different kinds. ) Diphenyl disulfides and / or general formula [II] (In the formula [II], R ^{9 to} R ¹² each represent a hydrogen atom, a halogen atom, a lower alkyl group or a lower alkoxy group, and R ^{9 to} R ¹² are the same kind or different kinds. When a polyarylene sulfide is produced by oxidative coupling polymerization of a thiophenol represented by the formula (1) in the presence of an acid, a polymerization reaction is carried out in two steps, and a polymerization in the first step is carried out. Production of a polyarylene sulfide, characterized in that a polymer or a polymer-containing substance is separated from the reaction mixture obtained by the reaction, and the obtained polymer or polymer-containing substance is used for a second-stage polymerization reaction. Law. 2. The method according to claim 1, wherein the polymer is separated from the reaction mixture obtained in the first stage polymerization reaction by introducing the reaction mixture into a precipitating agent. 3. The method according to claim 1, wherein the polymer-containing substance is separated from the reaction mixture obtained in the first-stage polymerization reaction by removing volatile components from the reaction mixture. .