JPS63221129A - Separation and recovery of aromatic ether sulfone polymer - Google Patents

Abstract

PURPOSE:To obtain the title polymer low in a content of residual reaction solvent, by adding a cyclic ether to a mixture of a specified aromatic sulfone solvent with an aromatic ether sulfone polymer. CONSTITUTION:Alkali metal (halo)bisphenates of formula I and/or formula II (wherein X is a halogen and M and M' are each an alkali metal) are reacted with a dihalo compound of formula III at 250-400 deg.C in an aromatic sulfone solvent of formula IV (wherein Y is a direct bond, O bonded to the benzene rings or a pair of hydrogen bond and Z and Z' are each H or phenyl) to obtain a mixture of an aromatic ether sulfone polymer with the solvent. This mixture is added, as a liquid or after solidification by cooling and cutting to a suitable size, to 2-5vol., per vol. of this mixture, cyclic ether and settled to obtain an aromatic ether sulfone polymer of a content of a residual reaction solvent <=200ppm.

Description

DETAILED DESCRIPTION OF THE INVENTION (Prior Art) The present invention relates to the production of aromatic polymers, and more particularly to an improved method for separating aromatic polymers from a produced reaction mixture (hereinafter referred to as crude reaction liquid). The aromatic polymers to which this invention relates are aromatic ether sulfone polymers containing phenylene groups linked by oxygen and sulfone groups. There are many ways to make such polymers, e.g.
9, JP 53-12997. There is JP-A No. 53-34900, etc. In any case, the crude liquid after the reaction contains the by-product salt 9 and the reaction solvent in addition to the above-mentioned polymer. It is necessary to separate the polymer from the reaction solvent and by-product salts. Remaining reaction solvent in the polymer generally has undesirable effects. For example, if a large amount remains, it may cause problems such as the polymer not being able to exhibit sufficient mechanical strength or foaming during polymer formation. Decomposition of the solvent causes undesirable effects (for example, increased coloration and decreased physical properties). From this point of view, it is better that the residual amount of the solvent is as low as possible. For example, JP 51-134
No. 799 describes that separation is carried out by precipitating a polymer from a reaction crude solution by adding water and an organic solvent such as 1 or methanol. For example, JP-A-50゜2
Another method using a reaction solvent with a relatively high melting point, such as that described in US Pat. and are removed by extraction with water and an acetone/methanol mixture. This method requires a special pulverizer such as a mill, requires a large amount of extractant, and leaves a small amount of reaction solvent in the polymer. Furthermore, since several types of solvents are used, their recovery becomes complicated. For example, equity 60-35
931, when a reaction solvent with a relatively high melting point is used for aromatic polyetherketone-sulfone copolymer, the reaction solvent is distilled off by heating after finely pulverizing, and the by-products are removed by washing. There is a method for removing the raw salt, but in the case of aromatic ether sulfone polymers, the crushed particles coalesce together during the distillation removal step of the reaction solvent, ultimately making it difficult to handle. For example, equity 52-275
There is also a method of purifying aromatic ether sulfone polymers derived from 3.3',5.5'-tetraalkyl-nyl from cyclic ethers by spontaneous reprecipitation as described in 00; Because the polymer is dissolved in formula ether, the yield is poor because the polymer remains in the solution.

(Means for solving the problem) The present inventors have intensively studied a method for efficiently removing a polymer from a crude reaction solution of an aromatic ether sulfone polymer and reducing the amount of reaction solvent remaining in the polymer. As a result, we have discovered a method that can easily recover a polymer with an extremely low amount of residual reaction solvent, and have arrived at the present invention. That is, the inventors have determined that the formula [where Y is a direct bond, oxygen, or a pair of hydrogen bonds (each bonded to a benzene ring), and 2 and 2' may be the same or different; Often a hydrogen atom or a phenyl group. ] When separating an aromatic polyether sulfone polymer from a mixture obtained by polymerizing at least one alkali metal bisphenate and at least one dihalo compound in an aromatic sulfone solvent represented by This is a method for separating and recovering aromatic ether sulfone polymers, which is characterized by adding the mixture, which has been cooled, solidified, and cut into a certain size, into a cyclic ether and mixed. Preferred aromatic ether sulfone polymers used include at least one alkali metal halophenate represented by the formula (wherein X is a halogen and M is an alkali metal) and l or the formula (wherein at least one of M and M' is It is obtained by polymerizing at least one kind of alkali metal phenate represented by the formula (representing an alkali metal) and at least one kind of dihalo compound represented by the formula (wherein X represents a halogen). Diphenylsulfone is preferred as the aromatic sulfone solvent. However, other solvents that can be used include dibenzothiophene dioxide, phenoxathiine dioxide and
-Phenylsulfonylbiphenyl. The polymerization is generally carried out at a temperature of 250 DEG to 400 DEG C. and the reaction is terminated by the addition of a chain terminator, such as methyl chloride. At this point, the reaction crude liquid is approximately 55% by weight. When cooled thereafter, the reaction crude liquid solidifies [along with the alkali metal halide (by-product salt) which is generally insoluble in aromatic sulfone solvents]. If hot filtration is performed before solidification, it is possible to desalt to a concentration of about 30 ppm based on the weight of the polymer. The mixture of the reaction crude liquid solidified together with the above-mentioned by-product salt is made into a certain size, although not particularly limited, preferably about 2 cm.
(below) or a mixture of the crude reaction liquid in liquid form is added to cyclic ether, preferably 1,4 dioxane, and tetrahydrofuran and mixed, specifically, preferably a fine powder from which most of the reaction solvent has been removed. A mixture of shapes is obtained. (At this point, the concentration of residual solvent in the polymer is 4
The amount of cyclic ether which is important in this operation depends on the amount of the reaction crude liquid added, and if the amount is less than twice the amount of the reaction crude liquid added, it will be difficult to filter the cyclic ether. Further, even if more than 5 times the amount is used, no significant change is observed, so this is not considered to be an economically good method. Further, as for the temperature and pressure, conditions such as heating and pressurization may be used if necessary, but it is not so necessary and the operation is usually performed at room temperature and pressure. Next, the finely powdered polymer is decomposed by filtration or the like, and the cyclic ether is added to the polymer again.

In this case, there is no need for stirring and there is no limit to the amount of cyclic ether added, but for economic reasons it is desirable to add about three times the amount. The time required for impregnation is only a few minutes, and there is no need for a longer period of time. Thereafter, the polymer is taken out by filtration and left to stand in cyclic ether. By repeating this operation several times, the concentration of the residual reaction solvent in the polymer becomes 200 ppm or less. If by-product salts are included, the by-product salts can be removed by washing with water or the like. By the above method using a cyclic ether, a finely powdered polymer having an extremely low concentration of residual reaction solvent can be recovered. The finely powdered polymer thus separated can be dried to remove volatile components, and then pelletized using an extruder or the like.

(Effects of the present invention) A finely powdered aromatic ether sulfone polymer can be obtained from the aromatic ether sulfone polymer separation and recovery method of the present invention. Additionally, since there is no stirring during cleaning, energy and time consumption is low. Furthermore, since the amount of residual solvent in the obtained polymer is very small, there is no deterioration in physical properties during molding.

(Examples) The present invention will be explained in the following Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 In a three-necked flask equipped with a nitrogen purge, a stirrer, and an air condenser, 4,4-dihydroxydiphenylsulfonylsulfone (63.4 g 0.22 mol), diphenylsulfone (149.8 g), potassium carbonate ( 31.
3g 0.29mol) was added. The flask was heated to 280°C on a metal bath for 6 hours. Methyl chloride was then bubbled through to stop polymerization. KCI was removed from this reaction crude liquid by hot filtration, and the mixture was poured through a tube into a beaker containing dioxane (1249 g) while stirring with a stirrer. After 6 hours, the crude liquid became a fine powder. This slurry was filtered and the cake was washed with dioxane (57.
After transferring it to a beaker containing 5g) and leaving it for about 5 minutes,
Filter and separate solid and liquid. This operation was repeated six times.

The obtained cake was dried in a vacuum dryer at 50°C, 2 Torr, 3
Dry for an hour. The concentration of residual diphenyl sulfone in the obtained finely powdered polymer was 200 ppm or less (exceeding the gas chromatography detection range).

Example 2 A reaction crude liquid prepared in the same manner as in Example 1 was desalted by hot filtration, cooled and solidified, and cut into approximately 1 cm square pieces. Add to the mixture and stir vigorously. The number of revolutions is approximately 6000
It was rpm. After 20 minutes, the reaction crude liquid was finely powdered. (420 pm or less: 94%) This was washed and dried in the same manner as in Example 1.

The amount of reaction solvent remaining in the polymer was 200 ppm or less. In addition, the remaining KCI concentration in the polymer was 64 pp.
It was m. Also, the apparent high specific gravity of this polymer is 0.27
g/cc.

Example 3 An experiment similar to Example 2 was conducted except that dioxane was replaced with tetrahydrofuran (THF). The reaction crude liquid was finely powdered, the subsequent washing was carried out smoothly, and the amount of remaining reaction solvent was 200 ppm or less.

Comparative Example 1 The reaction crude liquid prepared as in Example 1 was solidified and cut into approximately 1 cm square pieces using the same apparatus as in Example 1, using acetone as the solvent. After 30 minutes, the respective crude liquids coalesced into a lump that could not be stirred.

Comparative Example 2 An experiment was carried out in the same manner as in Example 2, except that the solvent was changed from acetone to methanol. Although the mixture was stirred for 10 hours, the shape of the crude liquid hardly changed.

(Volunteer to write procedural amendments) Kunio Ogawa, Commissioner of the Patent Office, August 1986-1b Separation and Recovery Method for Aromatic Ethersulfone Polymers 3, Relationship with the case of the person making the amendments Patent Applicant Zip Code 590 Address Osaka 1 Teppo-cho, Fusakai City Name (290) Daicel Chemical Industries, Ltd. Representative Yoshifumi Kubota 4, Column 5 of the detailed explanation of the invention in the specification subject to the amendment, and the contents of the amendment are corrected as shown in the attached sheet.

(1) “Preferably do” on page 7, line 12 of the specification was corrected to “preferably stir”.

(1) On page 8, line 1, “pressure, etc.” was corrected to “pressurization, etc.”

(1) Corrected “F decomposition” in line 4 on page 8 to “separation”.

(1) Same page 10 line 8 r 2 Torr J r 2 Torr
Corrected by J.

(1) "In a polymer" on page 10, line 9 "in a polymer"
Corrected.

(1) On page 10, line 19, “94%” was corrected to “r 94wt%”.

Claims (1)

[Claims] Formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, Y is a direct bond, oxygen, or a pair of hydrogen bonds (each bonded to a benzene ring), and Z and Z' are Hydrogen atoms or phenyl groups may be the same or different. ] In separating the aromatic ether sulfone polymer from a mixture obtained by polymerizing at least one alkali metal bisphenate and at least one dihalo compound in an aromatic sulfone solvent represented by 1. A method for separating and recovering aromatic ether sulfone polymers, which comprises adding the mixture, which has been cooled, solidified, and cut to a certain size, into a cyclic ether and mixed.