JPS59136326A - Production of polyether sulfone - Google Patents

Abstract

PURPOSE:To obtain a polyether sulfone having excellent heat stability and improved color tone, by thermally dehydrating a dihydric phenol, a dihalobenzenoid and sodium hydroxide in a sulfone solvent, and heating the product in the presence of potassium carbonate. CONSTITUTION:A mixture of (A) (i) one or more dihydric phenols and (ii) equimolar amount of one or more dihalogenobenzenoid compounds (wherein the halogen atom is activated by the -SO2-group existing at the o- or p-position of the halogen atom) and (B) NaOH of the amount to satisfy the formula I (x is the number of gram-equivalent of Na in the system; y is the number of gram-equivalent of phenolic OH group in the system), is heated in (C) a sulfone solvent at 100-250 deg.C while removing the water from the system to dehydrate the reaction mixture. The reaction mixture is added with (D) K2CO3 of the amount of satisfy the formula II (z is gram-equivalent of K of the K2CO3) and heated successively at 150-250 deg.C to obtain the objective polyether sulfone.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyether sulfone, and more particularly to a method for producing polyether sulfone having excellent thermal stability and improved color tone.

Polyether sulfone, in which aromatic rings are bonded by sulfonyl groups, is widely recognized for its usefulness due to its excellent heat resistance, oxidation resistance, hydrolysis resistance, and steam resistance, and is used in various applications including industrial materials. As is well known, it is used in the field of

Various methods have been proposed for the preparation of polyether sulfone.A representative method is the method described in Japanese Patent Publication No. 42-779.
No. 9 and Tokko 1977-. As disclosed in Japanese Patent Application No. 21318, this method involves polycondensing a dialkali salt of a dihydric phenol produced from a dihydric phenol and an alkali metal hydroxide with a dihalobenzenoid compound. If the molar ratio of phenol and alkali metal hydroxide is not strictly set to 1 = 2, side reactions will occur and the dihalobenzenoid compound will be hydrolyzed, resulting in stronger coloration and difficulty in increasing the molecular weight. There is.
Therefore, in this case, the above-mentioned molar ratio must be adjusted with high precision, which is always a hassle.

On the other hand, a method has also been proposed in which a mixture of dihydric phenol, alkali metal carbonate, and dihalobenzenoid compound is heated in a polar solvent to cause polycondensation. (
(Japanese Patent Publication No. 46-21458, Japanese Patent Publication No. 55-23574) In this method, the amount of alkali metal carbonate used relative to dihydric phenol is not required to be very strict, and the alkali metal carbonate is used in excess of the stoichiometric amount. However, potassium carbonate is expensive, and the cheaper sodium carbonate has a slow polymerization rate, and a polymer with a molecular weight that can withstand practical use cannot be obtained unless the polymerization temperature is raised.

Japanese Patent Publication No. 56-2091 proposes the combined use of sodium carbonate and potassium carbonate as a system in which the alkali carbonate used is inexpensive and has a high polymerization rate. However, the method proposed here is
When a relatively low polymerization temperature of .degree. C. or lower is employed, it is not necessarily effective and is insufficient to obtain the desired polymer in a short period of time.

The present inventors investigated the possibility of obtaining a polymer with little coloring through short polymerization under relatively mild conditions, and found that a surprisingly stable polymerization was achieved quickly using a rough preparation method that did not require relatively precision. The present invention has been achieved by discovering a method by which a polymer with little coloration can be obtained at low cost.

The present invention comprises (1)+1) substantially equimolar amounts of (a) at least one dihydric phenol and lb) at least one dihalobenzenoid compound (in which the haloken atoms are orthogonal to the same atom). or in rose position -802
- group) and (11) formula (1)
Sodium hydroxide in an amount that satisfies 0.9≦-<
1 (1) However, X: number of Durham equivalents of Na metal in the system y: number of Durham equivalents of phenolic hydroxyl groups in the system. After the reaction mixture has become substantially anhydrous,
Add potassium carbonate in an amount that satisfies formula (2),
Continue in the temperature range of 150-250℃□≦1.2
(2) where x and y are the same as above 2: Durham equivalent number of potassium metal of potassium carbonate to be added;

The dihydric phenol used in the present invention is hydro-OH (where X is a direct bond, -〇-1-S-, -5O2-nol). Particularly, hydroquinone, 4,4'-dihydroxydiphenyl, 4, 4'-dihydroxydiphenylsulfone is preferred.

The dihalobenzenoid compound used in the present invention is a compound having two halogen atoms activated by a 15O2- group at the ortho or para position of the benzene ring, and the halogen atom is preferably a chloro atom. . Preferred examples include bis(4-chlorophenyl)sulfone, bis(4-lylorphenylsulfonyl)diphenyl,
This is a representative example.

The sulfone solvent used as a polymerization solvent in the present invention is an aliphatic or aromatic sulfone, and preferred examples include dimethylsulfone, tetramethylenesulfone,
Mention may be made of diphenyl sulfone, with tetramethylene sulfone being preferred.

The method of the present invention is characterized in that sodium hydroxide and potassium carbonate are used in combination as alkali metal compounds necessary for polycondensing dihydric phenol and dihalobenzenoid compound, and sodium hydroxide and potassium carbonate are also used together. A major feature is that each limited amount of potassium carbonate is divided and used. By such a method, a polymer with improved coloration can be obtained at a relatively low temperature and in a shortened time, and a cost-effective method has been achieved.

The amount of sodium hydroxide used is such that it satisfies formula (1).

09≦−<1 (1,) However,
X: number of Durham equivalents of the amount of sodium gold in the system y: number of I equivalents of phenolic hydroxyl groups present in the system, that is, the number of Durham equivalents of sodium metal with respect to 1 gram equivalent of phenolic hydroxyl groups is 0.9 or more, 1 An amount of sodium hydroxide is used such that the amount of sodium hydroxide is less than or equal to

If the value is 1 or more, a side reaction will occur and a polymer with a sufficiently high molecular weight cannot be obtained, and if it is less than 0.9, the amount of potassium carbonate to be added must be increased, which is contrary to the purpose of the present invention. It will be damaged.

The amount of potassium carbonate to be added is such that it satisfies equation (2).

However, x and y are the same as above. Therefore, the amount of potassium carbonate used increases, and there is no cost advantage. When it is 1 or more, a side reaction occurs between sodium hydroxide and the dihalobenzenoid compound, so that not only the coloring of the obtained polymer becomes intense, but also the molecular weight becomes difficult to increase.

Potassium carbonate has a sum of Durham equivalents of sodium metal and potassium metal of greater than 1, preferably 1.2 or less, and preferably 1.1 or less, based on 1 gram atom of phenolic hydroxyl group present in the system at the time of starting the reaction. However, if it is less than 1, the molecular weight will not be high enough, and 1.
Even if more than 2 is used, the reaction rate will not increase accordingly and there will be no economic advantage.

It is important to add sodium hydroxide and potassium carbonate separately. That is, a mixture of a dihydric phenol, a dihalobenzenoid compound, and sodium hydroxide in a sulfonic solvent is heated to remove water, allowed to react, and potassium carbonate is added after the system is substantially anhydrous. This is one of the features of the present invention. Adding potassium carbonate in the presence of water improves the molecular weight as desired b! - Not only does it fail, but it also causes coloration in the resulting polymer.

The temperature of 1i[5 is 100 to 250°C in the first stage of reaction by adding sodium hydroxide, preferably 11
The temperature is 0 to 200°C. It is preferable to gradually increase the temperature as water is removed.

The reaction temperature in the second stage after addition of potassium carbonate is 150-2
50°C, preferably 180-220°C. Although the dihydric phenol and the dihalobenzenoid compound are used in substantially equimolar amounts, the dihalobenzenoid compound can be used in excess of up to 5 mol, preferably up to 3 mol φ.

If it is used in excess of more than 5 mol, the polymer will have a low molecular weight, which is not preferable.

In step 6 of the first stage of the present invention, hydroxylation is performed) IJ
In many cases, it is convenient to use it as an aqueous solution from the viewpoint of preparation accuracy, but the water produced when sodium hydroxide and dihydric phenol react to form the sodium salt of dihydric phenol. It is important to promptly remove all substances from the system. These waters are 1
It is preferable to remove at 00 to 150°C.

Although an azeotropic solvent may be used to remove water from the system, it is preferable to remove the water from the system without using an azeotropic solvent for the purpose of shortening the polymerization time. Water can also be distilled off under reduced pressure if necessary.

The polymerization reaction can be stopped by adding a terminal capping agent (for example, methyl chloride, t-butyl chloride, bis(4-chlorophenyl)sulfone), if necessary.

The polymer obtained according to the invention can be recovered by pouring the polymer solution into water or other non-solvent by a known method.

The alkali metal halide produced as a by-product during polymer production may be removed by separation before recovering the polymer, but it can also be removed by extraction with water or hot water after recovering the polymer.

The present invention is directed to a method for producing a polymer with little coloring quickly and at low cost at a relatively low temperature by adding two types of alkali metal compounds in portions.
Furthermore, it has been found that it is highly effective when industrial-scale production is considered.

It goes without saying that the ability to use inexpensive sodium hydroxide is an advantage, but conventional technology requires the amount of IJium to be strictly 2:1 (molar ratio). I was forced to do it. As mentioned above, the problems caused by too much or too little sodium hydroxide are involved in strictly controlling the molar ratio. However, in the present invention, although cheap sodium hydroxide is used, the amount of sodium hydroxide (per 1 gram equivalent of phenolic hydroxyl group) is 0.9 to 1 in terms of IJium metal.
The width can be tolerated and the deficiency can be made up with potassium carbonate, which does not have any negative effects even if used in excess.

Even when using potassium carbonate, a width that does not require much strictness is allowed, which brings great advantages in terms of process and quality control.

The polymer obtained by the present invention can be used for electrical insulation purposes, heat-resistant parts, cooking utensils, coating materials, precision parts, etc. due to its excellent heat resistance, stability, and high mechanical strength.

The present invention will be explained below with reference to Examples.

In addition, in the examples, the color tone is the yellowness (Y, Il) measured with a press plate of 1fIrIn thickness, and is expressed by Suga Test Instruments
The measurement was carried out using an automatic color difference meter manufactured by K.K.

ts: Outflow time of polymer solution to: Outflow time of pure solvent C: Concentration of polymer solution (g/l 0 omx) Measurement is N
-0.5 El/100m7 in methylpyrrolidone! The test was carried out at a concentration of 30°C and a temperature of 30°C.

Example 1 18.60 g of 4,4'-dihydroxydiphenyl was added to a flask equipped with a stirrer, nitrogen inlet, thermometer and receiver-tipped condenser. ? (0.10 mol) 16.33.9 (0.196 mol) of 48 sodium hydroxide aqueous solution was added and stirred for 10 minutes at room temperature under nitrogen atmosphere. Nibis(4-chlorophenyl)sulfone 29.27g (0,
102 mol) and 90 rnl of tetramethylene sulfone were added, and the temperature was gradually raised to 180°C while stirring while slowly introducing nitrogen into the liquid from the nitrogen inlet. During this time,
Total about 12m/! of water was used. After reacting at 180°C for 1 hour, anhydrous potassium carbonate (purity 99.5%) o, 9
7. ! i! (0,007 mol) was added to the reaction mixture;
Subsequently, the reaction was continued at 180° C. for 4 hours to complete the polymerization. 90 ml of tetramethylene sulfone was added to the reaction solution to form a homogeneous solution, and then cooled to 90°C. The reaction solution was gradually poured into a mixer containing a 500 m6 water tank while vigorously rotating, and the polymer was precipitated as a white powder. After three wash extractions of 10 minutes each in a mixer using fresh hot water, an additional hot methanol wash was performed. 2 at 180℃
Vacuum dry for 0 hours, f(inh = 0.551,
Y, 1. 39.7 g of a polymer of =42.6 was obtained.

Comparative Example 1 Polymerization, polymer recovery, purification, and ? Drying was performed. Polymer yield 39.2g, ? finh
= 0.324, and it was brittle and could not be molded into a satisfactory 1-keishi by hot pressing. This also shows the effect of adding potassium carbonate in Example IK.

Comparative Example 2 Immediately after adding tetramethylene sulfone in Example 1, potassium carbonate was added, and then the temperature was gradually raised to 180°C while stirring while slowly introducing nitrogen into the liquid. The amounts of monomer and solvent used were the same as in Example 1, except that the polymerization was carried out at 180° C. for 5 hours.

Post-treatment was carried out in the same manner as in Example 1 to obtain 39.4 g of polymer. The polymer had a satisfactory high molecular weight with Kainh = 0.30.9.

Comparative Example 3 In a flask equipped with a stirrer, a nitrogen inlet, a thermometer and a condenser with a receiver at the tip, 4,4'-dihydroxydiphenyl 18.60.9 (0.10 mol), 48% hydroxylated Sodium aqueous solution 17.0f19 (0205 mol)
was added and stirred for 10 minutes at room temperature under a nitrogen atmosphere. After that, screws (
4-chlorophenyl) sulfone, tetramethylene sulfone, and anhydrous potassium carbonate were added to carry out polymerization, and 395 g of each polymer with i nh −=0.395 was recovered.

Only brittle molded plates were obtained from this polymer. Y
, I, = 127, and the coloring was extremely intense.

Comparative Example 4 Anhydrous sodium carbonate (purity 99.5%) 075.9 (purity 99.5%) was used instead of the anhydrous potassium carbonate used in Example 1.
0,007 mol) was used. Polymerization and post-treatment were carried out in the same manner as in Example 1, and N1nh-0,4
09, Y, I, = 68. Polymer 39.2F of L was obtained.

Examples 2 to 6 Into a flask equipped with a stirrer, a nitrogen inlet, a thermometer, and a condenser with a receiver attached to the tip, dihydric phenol and 48Lf6 aqueous sodium hydroxide solution as shown in Table 1 were charged and the mixture was heated to room temperature. , and stirred for 10 minutes under nitrogen atmosphere.
Thereafter, a dihalobenzenoid compound and tetramethylene sulfone were added as shown in Table 1, and the temperature was gradually raised to 180°C while stirring. During this time, only the expected amount of water was used.

After reacting at 180°C for 1 hour, anhydrous potassium carbonate was added to Table 1.
Add the amount shown in , raise the temperature to 200℃, and heat at 200℃ for 4 hours.
The reaction was continued for an hour to complete the polymerization.

After that, the polymer was separated, recovered, and purified in the same manner as in Example 1. The results are summarized in Table 1.

(16) Comparison fRs Instead of the aqueous sodium chloride solution used in Example 1iC, anhydrous sodium carbonate (purity 9111G) 10.4
Using 4Jl (0,098 mol), the reaction was carried out in the same manner as in Example 1 to obtain a polymer of N1nh -0,339 3
9.8j was recovered.

Patent Dejima withdrawal Showa Denko Co., Ltd. Agent: Patent attorney Sei Kikuchi (19)-222-

Claims (1)

[Scope of Claims] (I) (i) Substantially equimolar amounts of (a) at least one dihydric phenolic compound (b) at least one dihalobenzenoid compound (halogen atoms in the compound are the same) (activated by the -SO□- group in the ortho or para position to) and (11) an amount of sodium hydroxide 0.9≦-<1 that satisfies formula (1). However, x: number of Durham equivalents of Na metal in the system y: number of gram equivalents of phenolic hydroxyl groups in the system. (Il+) Then, after the mixture becomes substantially anhydrous, add potassium carbonate in an amount such that it satisfies formula (2), and continue heating at a temperature range of 150-250 °C. An improved method for producing polyether sulfone characterized by