JPH05255505A - Method for producing polyether sulfone - Google Patents

Abstract

(57) [Summary] [Objective] A method for producing a polyether sulfone by removing water by-produced during polycondensation by using an inorganic desiccant. [Structure] In a method for producing a polyether sulfone by polycondensing a dihalogenodiphenyl compound and a dihydric phenol compound in an organic polar solvent in the presence of an alkali metal compound, water by-produced by using an inorganic desiccant is used. A method for producing a polyether sulfone, which comprises removing.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyether sulfone which removes water by-produced during polycondensation with an inorganic desiccant.

[0002]

2. Description of the Related Art Polyether sulfone is
A method for producing a polycondensation reaction of a dihalogenodiphenylsulfone and a dihydric phenol compound in the presence of an alkali metal compound in an organic polar solvent has been proposed. Alternatively, it is known that an alkali metal di-salt of a dihydric phenol is synthesized in advance and obtained by a polycondensation reaction with dihalogenodiphenyl sulfone (Japanese Patent Publication No. S42).
-7799, JP-B-45-21318, JP-A-48
-19700). Water is by-produced in the polycondensation reaction. When this water is present in the reaction system, the dihalogenodiphenylsulfone is hydrolyzed and a low molecular weight product is produced, so that a high molecular weight polymer practical as a desired molded article cannot be obtained. For example, in dimethyl sulfoxide, 1
It is known that dihalogenodiphenylsulfone is easily decomposed at a reaction of dihalogenodiphenylsulfone and an aqueous solution of potassium hydroxide at 20 ° C. to form a halophenol and a dihydric phenol (JB Rose et al., P
polymer 13 (8), p. 465 (197)
2)). In order to solve the above problems, in the production of polyether sulfone, when dihydric phenol is used simultaneously with dihalogenodiphenyl sulfone and an alkali metal compound in the presence of an organic polar solvent, benzene, toluene, halogenated benzene, etc. There is known a method in which by-produced water is removed as a hydrous azeotrope by adding the azeotrope-forming solvent. However, using an azeotrope-forming solvent, after the reaction is completed, when a poor solvent such as water or alcohol is added to the reaction solution when the polymer is isolated,
Since the organic polar solvent is a multi-component system, there is a problem that the recovery process is complicated.

[0003]

The inventors of the present invention have conducted research for the purpose of solving the above-mentioned problems, and as a result, did not require an azeotrope-forming solvent and could carry out polycondensation with a simple apparatus and operation. Through the reaction, a new method for producing a polyether sulfone in which a molded article has a practical strength was found, and the present invention was accomplished.

In the present invention, in the presence of an alkali metal compound,
In a method for producing a polyether sulfone by polycondensing a dihalogenodiphenyl compound and a dihydric phenol compound in an organic polar solvent, a high molecular weight compound characterized by removing by-product water using an inorganic desiccant is used. A method for producing a polyether sulfone is provided.

The inorganic desiccant used in the present invention may be any desiccant which is capable of selectively removing water by-produced or water present in the system and which is inert to the reaction system and the solvent system. Examples of the desiccant include molecular sieves, silica gel, activated alumina, anhydrous calcium sulfate, anhydrous magnesium sulfate, and anhydrous sodium sulfate. Particularly, molecular sieves 3A and 4A are preferable. Furthermore, these desiccants may be used alone and / or in combination of two or more. The amount of the desiccant used is preferably slightly in excess of the amount capable of adsorbing the theoretical amount of by-produced water. The desiccant may be added to the reaction tank in advance, or water by-produced may be separated from the reaction system together with the solvent and then dehydrated with the desiccant. In the former case, it is necessary to separate and recover the desiccant from the reaction solution, but in the latter case, there is an advantage that the dried solvent can be recycled and used.

Examples of alkali metal compounds include alkali metal carbonates, alkali metal hydroxides, alkali metal hydrides, and alkali metal alkoxides. Particularly, sodium carbonate and potassium carbonate are preferable. The alkali metal compound may be heat-treated in an inert gas such as nitrogen gas at 60 to 500 ° C. under normal pressure or reduced pressure for 1 minute or more before the polycondensation reaction.

The organic polar solvent in the present invention is not particularly limited as long as it dissolves the produced polymer at the polycondensation temperature. For example, sulfoxide-based solvents such as dimethyl sulfoxide and diethyl sulfoxide, amide-based solvents such as N, N-dimethylformamide and N, N-dimethylacetamide, N-methyl-2-pyrrolidone and N-vinyl-2.
-Pyrrolidone-based solvents such as pyrrolidone, N-methyl-2
-Piperidone-based solvent such as piperidone, 1,3-dimethyl-2-imidazolinone, 2-imidazolidinone-based solvent such as 1,3-diethyl-2-imidazolidinone, hexamethylene sulfoxide, γ-butyrolactone, sulfolane, Alternatively, diphenyl compounds such as diphenyl ether and diphenyl sulfone may be mentioned. In particular, N-
Methyl-2-pyrrolidone and N, N-dimethylacetamide are preferably used because they are also excellent in reducing coloration.

The dihalogenodiphenyl compound is represented by the general formula (I)

[0009]

(I) (I) (In the formula, X and X ′ are the same or different halogen atoms.). Specific examples thereof include 4,4′-dichlorodiphenyl sulfone and 4,4′-difluorodiphenyl sulfone as the dihalogenodiphenyl compound.

Examples of the dihydric phenol compound include hydroquinone, catechol, resorcin, 4,4'-biphenol, bis (hydroxyphenyl) alkanes,
At least one hydrogen atom of dihydroxydiphenyl sulfones, dihydroxydiphenyl ethers or their benzene rings is substituted with a lower alkyl group such as a methyl group, an ethyl group or a propyl group, or a lower alkoxy group such as a methoxy group or an ethoxy group. You can list things. Alternatively, two or more kinds of the above dihydric phenol compounds may be mixed and used.

The dihydric phenol compound is generally used in a substantially equimolar amount with the dihalogenodiphenyl compound, but in order to control the molecular weight of the polyether sulfone, a slight excess or an excessively small amount is used. May be used in. For this purpose, a small amount of monohalogenodiphenyl compound or monohydric phenol compound can be added to the polymerization solution.

The polycondensation temperature depends on the characteristics of the solvent used, but is usually 140 to 250 ° C, and 150 to 20 ° C.
0 ° C is preferred. At the end of polycondensation, a methylating agent such as chloromethane may be added to the reaction solution as a polymer terminal stopper at 90 to 150 ° C.

Inorganic solids such as alkali metal carbonates, alkali metal halides or desiccants remaining in the reaction solution can be separated by filtering or centrifuging the reaction solution. After separating the inorganic solid contained in the reaction solution by filtration or centrifugation, or without separating the inorganic solid, a poor solvent can be added to the reaction solution to separate the polyethersulfone as a precipitated solid. .. Examples of the poor solvent for polyether sulfone include alcohols such as methanol, ethanol, isopropanol and butanol, nitriles such as acetonitrile, water and the like.
Further, two or more kinds of the above compounds can be mixed and used. Further, the poor solvent may contain a good solvent for the polymer such as the above-mentioned polymerization reaction solvent, within the range where the polymer can be precipitated.

A powder of polyethersulfone can be obtained by washing the precipitated solid with a poor solvent and then drying it.

According to the present invention, an inorganic desiccant such as molecular sieves is used to remove water produced as a by-product, so that it is highly reproducible and has excellent heat resistance, oxidation resistance and chemical resistance in a short time. High molecular weight polyether sulfones can be produced.

[0016]

The present invention will be specifically described with reference to the following examples.
The reduced viscosity (ηsp / c) in the examples is represented by the following formula. ηsp / c = (t−t ₀ ) / t ₀ / c where t: transit time between marked lines of the polymer solution in the viscometer (seconds) t ₀ : transit time between marked lines of the pure solvent viscometer (Sec) c; concentration of polymer solution (expressed in g / 100 ml solvent) The reduced viscosity was measured in a N-methyl-2-pyrrolidone solvent,
Conducted at 30 ° C., the concentration of the polymer solution is 0.5 g / 100
ml. Example 1 A 500 ml four-neck separable flask equipped with a water-cooled condenser water content determination tube equipped with a water-cooled condenser, 62.8 g of molecular sieves, a stirrer, a nitrogen inlet tube, and a thermometer were placed in a solvent, and N, N-dimethylacetamide 300 ml, 4,
57.40 g of 4'-dichlorodiphenyl sulfone, 10.74 g of hydroquinone, 4,4'-biphenol 1
Charge 8.16 g and anhydrous potassium carbonate 29.6 g,
Under a nitrogen atmosphere, the mixture was stirred and reacted at about 165 ° C. for 5 hours to obtain a polymerization solution. After completion of the reaction, after filtering the inorganic substance from the polymerization solution,
It was poured into a mixed solution of methanol-water to precipitate a polymer.
The precipitated solid was washed with water and dried under reduced pressure at 100 ° C. to obtain polyethersulfone powder. The reduced viscosity of the obtained polyether sulfone was 0.53. Example 2 62.7 g of molecular sieves, 300 ml of N-methyl-2-pyrrolidone, 23.1 of 4,4'-biphenol
8 g and 51.6 g of anhydrous potassium carbonate were used, and the same procedure as in Example 1 was carried out except that the reaction temperature was 180 ° C. to obtain polyethersulfone having a reduced viscosity of 0.52.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeru Yamamoto 8-1 Goi Minamikaigan, Ichihara City, Chiba Ube Industries Ltd. Chiba Research Institute

Claims (1)

[Claims] 1. A method for producing a polyether sulfone by polycondensation of a dihalogenodiphenyl compound and a dihydric phenol compound in an organic polar solvent in the presence of an alkali metal compound, which is by-produced by using an inorganic desiccant. A method for producing polyethersulfone, which comprises removing water. [0001]