JPH01319530A - Purification and separation of aromatic polyether polymer - Google Patents

Abstract

PURPOSE:To carry out the purification and separation of a polymer having low residual solvent content, uniform particle size and high bulk density, in high efficiency by cooling an aromatic polyether polymer mixture to form a precipitate, granulating the precipitate and removing by-products and reaction solvent from the granule. CONSTITUTION:A mixture composed of an aromatic polyether polymer, by- products (e.g., KCI) and reaction solvent (e.g., tetramethylene sulfone) is cooled to a temperature near the freezing point of the reaction solvent and the produced precipitate is granulated. The objective aromatic polyether polymer can be separated in purified state by removing the by-products and the reaction solvent from the granule. The obtained polymer has excellent heat-resistance and flame-retardance and is useful as a resin for the parts of electronic apparatus.

Description

Detailed Description of the Invention a9 Object of the Invention The present invention provides a method for purifying and isolating aromatic polyether polymers,
In particular, aromatic polyether polymers can be efficiently separated from aromatic polyether polymer mixtures, and have a high bulk density with a small amount of residual reaction solvent and by-products in the polymer. This invention relates to a purification and isolation method for obtaining conjugation.

(Field of Application of the Invention) The refining method of the present invention is applicable to electrical parts, electronic equipment parts, aircraft parts, automobile parts, sanitary food equipment, which have good heat resistance and flame retardancy, and excellent mechanical properties and electrical properties. It is advantageously used to obtain aromatic polyether resins that are widely used in parts and the like.

(Prior Art) Conventionally, a method of reacting a dialkali metal salt of a dihydric phenol with an aromatic cybaride is well known as a typical method for producing an aromatic polyether polymer. At this time, by using a polar inert solvent as a reaction medium, the reaction can be carried out at a relatively low temperature and the polymer and solvent can be efficiently separated. This is important in manufacturing.

Usually, a polymer mixture obtained by polycondensing a dialkali metal salt of a dihydric phenol and an aromatic cybaride in a polar solvent consists of a produced polymer, a by-product salt, and a reaction solvent. Various methods have been proposed for separating polymers from such polymer mixtures.

- As a method for boat fishing, Japanese Patent Publication No. 53-28341 discloses a method in which a polymer solution is dispersed as small droplets in a continuous carrier liquid and the solvent is extracted by bringing the polymer solution into contact with an aliphatic hydrocarbon. JP-A-59-74125 discloses a method in which a polymer solution is extracted and separated using a water-immiscible non-polar aromatic compound such as benzene or toluene. JP-A No. 59-109522 discloses a method in which a polymer is precipitated in a non-solvent solution to form granules, such as contact precipitation with a liquid polyhydric alcohol at room temperature, and by-product salt and reaction are extracted. Examples of such methods include removing the solvent. Furthermore, Japanese Patent Publication No. 52-39080 proposes a method in which an inert high-melting point solvent is used, the mixture is cooled to below the melting point of the solvent, solidified, pulverized, and then extracted with methanol, water, or the like. With these methods, even if most of the solvent can be removed, it is inevitable that a considerable amount of highly polar solvent remains, or even if a large amount of non-solvent can be used to recover a small amount of residual solvent. As a result, the polymer is recovered in a state where the apparent specific gravity (bulk density) is extremely high.

A decrease in bulk density is undesirable because the volume occupied when the polymer is dried or pelletized becomes too large, and the efficiency of pelletization decreases.

(Problems to be Solved by the Invention) The present invention aims to provide a granulation method for obtaining a polymer having a high bulk density and a small amount of residual reaction solvent and by-product salt of an aromatic polyether polymer. It is.

b1 Structure of the invention (means for solving the problem) The method for purifying and isolating an aromatic polyether polymer of the present invention is as follows:
When isolating an aromatic polyether polymer from an aromatic polyether polymer mixture consisting of an aromatic polyether polymer, a by-product, and a reaction solvent, the aromatic polyether polymer mixture is heated to a temperature close to the freezing point of the reaction solvent. This is a method for purifying and isolating an aromatic polyether polymer, which is characterized by cooling to form a precipitate and granulating it, and then removing by-products and reaction solvents. By-products here include, for example, halogenated alkali metal salts, such as KCI.

Such as NaCl. As a reaction solvent, dimethyl sulfoxide, tetramethylene sulfone, diphenyl sulfone, 1,3-dimethyl-2-imidazosilydinone is used.

N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylphosphorotriamide, N-
Examples include methyl-2-pyrrolidone, dimethyl sulfone, diethyl sulfone, diethyl sulfoxide and the like.

In addition, the aromatic polyether polymer of the present invention generally refers to (wherein Z is a direct bond, an alkylene or alkylidene group having 1 to 5 carbon atoms, or a cyclo cycloamide group having 5 to 15 carbon atoms). Represents an alkylene or cycloalkylidene group, or a group of 10-, -CO-, -5o2-, -s-.R1, R2-5= represents -CH3-, -c2H5-, -CH(CH3) 2-
, -0CH3-, -0C2H5- groups,
R1 and R2 may be the same or different. n1ln2
represents an integer from 0 to 4.

z'i, t -5o2- Also bar CO-theal. R3,
R4 bar CH3-, -C2H5-, -CH(CH3)2
-, 70CH3-.

-〇〇2H5-, and R1 and R2 may be the same or different. n1ln2 represents an integer from O to 4. ) has a repeating unit.

- As an example, having a repeating unit of the formula, and another example having a repeating unit of the formula.

Preferred systems for the present invention include systems of polyether sulfone polymer and tetramethylene sulfone as the reaction solvent.

Hereinafter, the method of the present invention will be explained in detail by way of example.

After the reaction is complete, the resulting polymer mixture is desalted or gradually cooled in a salt-containing state to near the freezing point of the reaction solvent.
A large number of nuclei were formed during this intermediate stage, and further growth of the nuclei was observed by slow cooling. Finally about 1100p ~ 1
Particles of about mm size are obtained throughout the system, and salts and reaction solvents can be easily removed from these by ordinary purification such as washing and extraction, and the obtained dried sample has a high bulk density or granular shape with very uniform particles. It was a product of Furthermore, it is also possible to perform the same treatment as above after adding a non-solvent to the polymer mixture as necessary to an extent that the polymer does not precipitate. Furthermore, from the perspective of shortening processing time,
It is also possible to add stirring at low speed. However, if the stirring intensity is excessive, the particle size tends to become small and the bulk density tends to decrease, so care must be taken. Here, non-solvents are those that do not dissolve the polymer, such as hexane in addition to water.

Hydrocarbons such as toluene, methanol, ethanol.

Examples include alcohols such as purpanol and butanol, and dialkyl ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.

Although the mechanism by which granules are formed by gradually cooling the polymer mixture is not clear, it is thought to be due to the formation of a complex between the polymer and the reaction solvent.

(Example) Examples will be described below. Measurements in Examples and Comparative Examples were carried out by the following method. The residual amount of solvent was measured by gas chromatography, and the bulk density was JIS Z-8.
Measured according to 807. Note that the ratios and amounts used in Koji are based on weight unless otherwise specified.

Example 1 Polyether sulfone (“Pictrex 4” manufactured by ICI)
800P”) 50g to 200g of tetramethylene
The resin solution dissolved at 0°C was heated to 70°C under stirring for 1 hour.
After the temperature was lowered to 30°C, the inside of the system was gradually cooled down to 30°C for 8 hours in a static system. At the initial 2-hour culm stage, stringy cores were observed, and with gradual cooling, the cores grew and granulation was observed.

The obtained granulated product was repeatedly washed four times with 750 g of methanol, and then solid-liquid was separated using a filtration or centrifugal separator. Furthermore, the residual solvent concentration of the polymer obtained by hot air drying at 145°C was 0.08% by weight, and the bulk density was 0.51g.
/cc.

Example 2 4,4'-dihydroxydiphenylsulfone (69,87g), 4,4'-dichlorodiphenylsulfone (82,15g) in a three-turn flask (capacity 1°C) equipped with a stirrer, condenser and nitrogen inlet. and sodium carbonate (31.23 g). Furthermore, tetramethylene sulfone (2oo, 98 g) was added as a reaction solvent,
Stir I2 and heat to 235°C under nitrogen flow. After 6 hours, tetramethylene sulfone (37
6.20 g) was added thereto, and casseous methyl chloride was passed through the solution for 1 hour. After removing by-product salt by filtration, the mixture was gradually cooled from 150°C to 30°C over about 10 hours. The obtained granulated product was washed four times with methanol (3 times the amount of the reaction crude liquid), separated into solid and liquid, and further dried with hot air at 145°C. The resulting polymer had a residual solvent concentration of 0.07% by weight and a bulk density of 0.53 g/cc.

Comparative Example 1 Polyether sulfone (“Pictrex 4” manufactured by ICI)
800p”) 50g tetramethylene sulpone 200g
A resin solution prepared by dissolving 150 g of methanol at 150° C. was added to a mixer containing 750 g of methanol in advance, and the process of pulverizing, slurrying, and washing with high-speed stirring was repeated four times.

The solid matter after the treatment was dried with hot air at 140°C. The residual solvent concentration of the obtained polymer was 0.11% by weight, and the bulk density was 0.1.
It was 1 g/cc.

Comparative Example 2 4,4'-dihydroxydiphenylsulfone (69,87g), 4,4-dichlorodiphenylsulfone (82,15g) and Sodium carbonate (31.23g) was fed. Furthermore, tetramethylene sulfone (200.98 g) was added as a reaction solvent, stirred, and heated to 235°C under a nitrogen flow. After 6 hours, tetramethylene sulfone (376,2
0 g) was added thereto, and a gas of 10-methyl chloride was passed through the mixture for 1 hour. After removing by-product salts by filtration, methanol (3 times the amount of the crude reaction solution) was added into a mixer, and the process of pulverizing, slurrying, and washing with high-speed stirring was repeated four times. The solid matter after the treatment was dried with hot air at 145°C. The residual solvent concentration of the obtained polymer was 0.13% by weight.

The bulk density was 0.14 g/cc.

(Effects of the Invention) As described above, according to the present invention, a granular polymer having a uniform particle size and a high bulk density with a small amount of residual solvent can be obtained, and therefore it can be effectively used in various applications requiring these properties. It will be done.

Claims (1)

[Claims] When isolating an aromatic polyether polymer from an aromatic polyether polymer mixture consisting of an aromatic polyether polymer, a by-product, and a reaction solvent, the aromatic polyether polymer mixture is heated to a temperature close to the freezing point of the reaction solvent. Cool and
A method for purifying and isolating an aromatic polyether polymer, which comprises forming a precipitate and granulating it, and then removing by-products and a reaction solvent.