JPH0676488B2 - Method for producing thermoplastic aromatic polyether - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention is a method for producing a thermoplastic aromatic polyether having excellent heat resistance, chemical resistance, and hydrolysis resistance during the reaction step without gelation. Regarding

<Prior Art> A method is known in which an aromatic compound having two hydroxyl groups and an aromatic compound having two halogen atoms are reacted in a polar solvent in the presence of potassium carbonate (Japanese Patent Publication No. Sho.
47-21595).

In addition, an aromatic compound having two hydroxyl groups and 2
A method of using a mixture of sodium carbonate and a carbonate of an alkali metal having a larger atomic number than sodium in polycondensation with an aromatic compound having one halogen atom is also known (Japanese Patent Laid-Open No. 53-97094).

<Problems to be Solved by the Invention> In the polymerization by an aromatic nucleophilic substitution reaction, a phenoxy anion is produced as an intermediate, but as a counter cation of this anion, potassium having a high reactivity is generally used. Ions are used. However, in the polycondensation of the divalent phenol and the dihalobenzenoid compound, if only potassium carbonate is used, a large amount of gel-like substance is generated. Further, even when a mixture of potassium carbonate and sodium carbonate is used, it is necessary to strictly control the mixing ratio in order to prevent the generation of a gel-like substance, which is a drawback that it is industrially difficult to use.

The present inventor has found the present invention as a result of extensive studies to solve the above-mentioned drawbacks.

<Means for Solving the Problems> That is, at least one divalent phenol and at least a dihalobenzenoid compound having an electron withdrawing group at at least one position of the ortho or para position with respect to a halogen atom. Provided is a method for producing a thermoplastic aromatic polyether, which comprises polycondensing one kind in a polar solvent in the presence of potassium carbonate and sodium sulfate.

The divalent phenol used in the present invention means hydroquinone and the general formula (In the formula, Y is a direct bond, —O—, —S—, —SO ₂ —,
-CO- or a divalent hydrocarbon group). Specifically, hydroquinone, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl sulfone, 2,
2'-bis- (4-hydroxyphenyl) propane, 4,
There are 4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl sulfide, and 4,4'-dihydroxydiphenyl ether, and particularly preferred divalent phenols are hydroquinone and 4,4'-dihydroxydiphenyl ether. Is.

Further, the dihalobenzenoid compound used in the present invention is an aromatic compound having an electron withdrawing group at at least one position of ortho or para position with respect to halogen.
Specifically, 4,4'-difluorobenzophenone, 4,4'-
Dichlorobenzophenone, 4,4'-difluorodiphenyl sulfone, 4,4'-dichlorodiphenyl sulfone, 4,
There are 4'-dichloroazobenzene and 2,4-dichloronitrobenzene, but 4,4'-difluorobenzophenone and 4,4'-dichlorobenzophenone are particularly preferable.

The polar solvent used in the present invention includes DMSO (dimethyl sulfoxide) and sulfolane (tetrahydrothiophene).
1,1-dioxide), diphenyl sulfone, NMP (N-methylpyrrolidone), HMPT (hexamethylphosphoric triamide) and the like. Since the thermoplastic aromatic polyether obtained by the present invention has a high melting point and is highly crystalline, it tends to precipitate from the solution when the polymerization progresses and the degree of polymerization increases. If precipitation occurs, the degree of polymerization will not increase any more, so it is necessary to finally polymerize at the melting point of the polymer or at a reaction temperature higher than that. Therefore, the polar solvent must be selected according to the melting point of the polymer. Among them, since diphenyl sulfone has a high boiling point of 380 ° C., it can be said that it is suitable for the combination of almost all the monomers described in the present invention.

In the production method of the present invention, it is necessary to replace the inside of the reaction vessel with nitrogen before heating and stirring the raw material mixture. This is because the phenoxy anion generated as an intermediate during the polymerization reaction is sensitive to oxygen and is easily oxidized. If nitrogen is not replaced, the color tone will be worse than if nitrogen was replaced,
Further, in a terrible case, the molar ratio of the monomer shifts, resulting in the degree of polymerization not increasing.

In the present invention, the degree of polymerization becomes highest when the molar ratio of the divalent phenol to the dihalobenzenoid compound is exactly 1: 1. Therefore, in order to obtain a polymer having a high degree of polymerization, one to one is preferable, but either one of the monomers may be used in a slight excess for controlling the molecular weight. In this case, the excess amount is preferably 5 mol% or less,
Particularly, 3 mol% or less is preferable. In addition, since it is more stable when the end is a halogen group than in a phenol group, it is better to use the dihalobenzenoid compound in excess.

As a method of adjusting the molecular weight, there is a method of adding a polymerization terminator in addition to using one monomer in excess as described above. As the polymerization terminator, a monohalobenzenoid or dihalobenzenoid compound having an electron-withdrawing group at at least one position of ortho or para to halogen is suitable. Specifically, 4-fluorobenzophenone, 4-chlorophenylsulfonylbenzene,
4,4'-dichlorobenzophenone, 4,4'-dichlorodiphenyl sulfone, 4,4'-difluorobenzophenone,
4,4'-difluorodiphenyl sulfone and the like.

In carrying out the present invention, the amount of potassium carbonate used as a condensing agent is an important value. Theoretically, the minimum amount of potassium carbonate required to completely convert all divalent phenols to phenoxy anions should be present. Therefore, the molar ratio of potassium carbonate to monomer is substantially
It should be one-to-one. However, in reality, the purity of the monomer and potassium carbonate is not 100%, and there is decomposition of the phenoxy anion.
In many cases, the degree of polymerization does not increase. Therefore, in order to obtain a polymer having a large molecular weight, it is necessary to change the molar ratio of potassium carbonate and the monomer for polymerization to determine the optimum molar ratio. In the present invention, potassium carbonate / monomer = 1.00
It is preferably in the range of to 1.10.

In the present invention, sodium sulfate is preferably added in an amount of at least 0.1 g, more preferably 1.0 to 300 g, per 1 mol of the monomer. Also, as far as possible the reaction system,
In order to make the particles uniform, the particle diameter is preferably 300 μm or less. The addition timing is preferably at the time of charging the raw materials together with other reagents, or at the initial stage of polymerization (reaction temperature of 250 ° C. or lower).

<Examples> Hereinafter, the present invention will be described with reference to Examples.

Example 1 25.11 g (0.10 m) of 4,4'-dichlorobenzophenone was placed in a polymerization reaction vessel equipped with a helical ribbon stirring blade and a nitrogen introducing tube.
ol), 4,4'-dihydroxydiphenyl 18.62g (0.10mo
l), 14.37 g of anhydrous potassium carbonate with a particle size of 300 μm or less (0.
104 mol), 5.0 g of anhydrous sodium sulfate and 60 g of diphenyl sulfone were charged, and the inside of the reaction vessel was replaced with nitrogen. The reaction vessel was heated to 180 ° C. under a nitrogen stream, and was gently stirred. 3
After 0 minutes, the temperature was raised and the temperature was kept at 250 to 270 ° C. for 1.5 hours. The temperature was further raised, and when the temperature reached 380 ° C. over about 2 hours, stirring was stopped and the mixture was cooled. When cooled, the reaction product solidifies, so this was taken out and pulverized to obtain a powder of 300 μm or less. This was extracted and washed with 300 ml of acetone to remove diphenyl sulfone. After that, the mixture was washed with a large amount of water to remove inorganic salts, and dried in vacuum at 120 ° C. overnight.

Repeating unit This polymer consists of concentrated sulfuric acid, 0.5g / dl concentration, 25 ℃
The logarithmic viscosity ηinh = 1.12 measured by the method of 1. and the film obtained by press molding at 450 ° C. was tough. The polymer was uniformly dissolved in concentrated sulfuric acid and had no gel.

Further, the melting point measured by Perkin-Elmer DSC-1B differential scanning calorimeter is 387 ℃, obtained from the temperature dependence curve of the dynamic viscoelasticity measured by Toyo Baldwin Rheovibron DDV-II-EA Glass transition temperature is 175
It was ℃.

Example 2 Polymerization and purification were conducted in the same manner as in Example 1 except that 11.12 g (0.10 mol) of hydroquinone was used instead of 4,4'-dihydroxydiphenyl, and the final temperature was 350 ° C.

Repeating unit This polymer consists of concentrated sulfuric acid, 0.5g / dl concentration, 25 ℃
The logarithmic viscosity ηinh = 0.94 measured in the above, and the film obtained by press molding at 400 ° C. was tough. The polymer was uniformly dissolved in concentrated sulfuric acid and had no gel.

Also, the melting point measured by Perkin-Elmer DSC-1B differential scanning calorimeter is 336 ℃, obtained from the temperature dependence curve of dynamic viscoelasticity measured by Toyo Baldwin Rheovibron DDV-II-EA Glass transition temperature was 151
It was ℃.

Example 3 Example 1 except that 3 g of 4,4'-difluorobenzophenone was added at the end of the reaction and the reaction was stopped by stirring for 30 minutes.
Polymerization was carried out in the same manner as in. 0.5g / dl concentration in concentrated sulfuric acid, 25 ℃
The logarithmic viscosity ηinh was 0.81 as measured by the above method, and the film obtained by press molding at 450 ° C was tough. Further, this polymer was uniformly dissolved in concentrated sulfuric acid, and there was no gel.

Example 4 Polymerization was carried out in the same manner as in Example 1 except that 60 g of sulfolane (tetrahydrothiophene 1,1-dioxide) was used as the polar solvent instead of diphenyl sulfone. However, the reaction temperature is up to 280 due to the low boiling point of sulfolane.
It was up to ℃. The logarithmic viscosity ηinh = 0.18 measured in concentrated sulfuric acid at a concentration of 0.5 g / 25 ° C., and the film obtained by press molding at 450 ° C. was very brittle.

Example 5 25.76 g (0.103 mol 3) of 4,4′-dichlorobenzophenone
Polymerization was carried out in the same manner as in Example 1 except that a mol% excess) was used. The logarithmic viscosity ηinh = 0.84 measured in concentrated sulfuric acid at a concentration of 0.5 g / dl at 25 ° C. The film obtained by press molding at 450 ° C. was tough. Further, this polymer was uniformly dissolved in concentrated sulfuric acid, and there was no gel.

Example 6 Polymerization and purification were carried out in the same manner as in Example 1 except that 0.01 g of anhydrous sodium sulfate was used. 0.5 g / dl concentration in concentrated sulfuric acid, 2
The logarithmic viscosity ηinh = 0.81 measured at 5 ° C., and the film obtained by press molding at 450 ° C. was tough. Further, this polymer was dissolved in concentrated sulfuric acid almost uniformly, but a very small amount of black floating matter was mixed.

Comparative Example 1 Polymerization and purification were carried out in the same manner as in Example 1 except that anhydrous sodium sulfate was not added. At the end of the polymerization, the viscosity increased, but a gel-like substance that did not dissolve in concentrated sulfuric acid was formed, and the viscosity could not be measured. Further, it was attempted to obtain a film by press molding at 450 ° C., but the melt viscosity was high and a uniform sample could not be obtained.

Comparative Example 2 26.76 g (0.107 mol 7) of 4,4'-dichlorobenzophenone
Polymerization was carried out in the same manner as in Example 1 except that a mol% excess) was used. The logarithmic viscosity ηinh = 0.30 measured in concentrated sulfuric acid at a concentration of 0.5 g / dl at 25 ° C. The film obtained by press molding at 450 ° C was brittle.

<Effect of the Invention> By using the production method of the present invention, it is possible to obtain a thermoplastic aromatic polyether having a small amount of gel.

Claims (1)

[Claims] 1. At least one divalent phenol and at least one dihalobenzenoid compound having an electron withdrawing group at at least one ortho or para position with respect to a halogen atom in a polar solvent, potassium carbonate and sodium sulfate. A method for producing a thermoplastic aromatic polyether, which comprises polycondensing in the presence.