JPH04275335A - Production of polyphenylene sulfide sulfone - Google Patents

Abstract

PURPOSE:To produce a polyphenylene sulfide sulfone with low contents of oligomers and impurities. CONSTITUTION:In a method for producing polymer of a polyphenylene sulfide sulfone using an N-alkyllactam as a solvent, the amount of water or the N- alkyllactam is reduced or added in separation by filtration. Thereby, the molar ratio of the N-alkyllactam : water is regulated to (0.3:1)-(2:1) and the molar ratio of the N-alkyllactam : polymer is regulated to (10:1)-(50:1).

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for obtaining polyphenylene sulfide sulfone containing few oligomers and impurities.

0002

[Prior art] Polyphenylene sulfide sulfone is
As a functional resin that is amorphous and has high heat resistance, it is being developed for use in injection molding, extrusion molding, films, etc. However, the viscosity during melting is high, and extrusion is generally carried out at temperatures exceeding 320°C, which causes problems such as gas generation from oligomers, increased deposits on molds and nozzles, and smoke generation. There was a problem that this resulted in a decrease in thermal stability. Furthermore, there is a problem in that ionic impurities such as alkali halide produced as a by-product during polymerization deteriorate the mechanical properties and electrical properties of the polymer molded product.

[0003] Methods for producing polyphenylene sulfide include JP-A-63-270736, JP-A-64-124, JP-A-1-101331, JP-A-1-110533,
No. 1-132633, etc., which describes the polymerization method, but does not describe a specific oligomer reduction method. Regarding oligomer reduction from similar polymers such as polyarylene sulfide, such as polyphenylene sulfide, washing with a solvent that does not dissolve the polymer as shown in JP-A-61-225217 and JP-A-61-255933, and furthermore, Kaisho 60-1
As shown in No. 15631 and No. 62-232437, washing with a polymerization solvent is known, but the method of re-washing the separated polymer with another organic solvent in a separate process makes the process complicated and has problems with cleaning efficiency. I can't say enough about it. Furthermore, since polyphenylene sulfide sulfone is soluble in N-alkyllactam, it is difficult to simply wash it with a polymerization solvent.

0004

SUMMARY OF THE INVENTION The present invention seeks to obtain polyphenylene sulfide sulfone with reduced oligomer and ionic impurities without complicating solvent recovery.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides the following method for producing polyphenylene sulfide sulfone. That is, an alkali metal sulfide and a dihalogen aromatic sulfone are reacted as raw materials in the presence of an alkali metal carboxylate and/or free water using an N-alkyl lactam as a solvent, and then cooled and a polymer is extracted from the reaction mixture. In the method for producing polyphenylene sulfide sulfone, the concentration of N-alkyl lactam is changed from water to N- at the time of filtration.
The molar ratio of alkyl lactam is from 0.3:1 to 2:1, and the molar ratio of N-alkyl lactam to polymer is from 10:1 to
The gist of the invention is a method for producing polyphenylene sulfide sulfone, which is characterized by adjusting the ratio to be 50:1.

[0006] In the polyphenylene sulfide sulfone obtained by this method, the acetone soluble portion in the polymer is 2.5% by weight or less, and the ash content in the polymer is 0.4% by weight or less. It is.

The polyphenylene sulfide sulfone in the present invention has the general formula

[Formula 1] It is a homopolymer or a copolymer having the repeating unit represented by the following as the main structural unit, and the main structural unit here means that at least 70 mol% or more of the above unit has the above unit, and less than 70% In this case, the solubility of the polymer in the N-alkyl lactam and the inherent properties of the polymer differ, making it difficult to apply the method of the present invention. If the amount is less than 30%, there is no problem even if it contains branches, substituted phenyl groups, other ketone, aliphatic, etc. bonds.

Such polyphenylene sulfide sulfone is synthesized by a known method from dichlordiphenyl sulfone and an alkali metal sulfide and/or alkali metal carbonate or alkali metal hydroxide in an N alkyl lactam solvent. Can be used. Furthermore, in order to obtain a polymer with a high molecular weight, it is also possible to carry out the polymerization using an auxiliary agent such as an alkali metal carboxylate.

[0009] The N-alkyllactam of the present invention includes:
Examples include N-methylpyrrolidone, N-ethylpyrrolidone, N-methylcaprolactam, and N-ethylcaprolactam, with N-methylpyrrolidone being preferably used.

In order to separate polyphenylene sulfide from the reaction mixture, the polymer must not be dissolved in the medium when it is separated, and the medium must contain a certain amount of water, which is a poor solvent. is necessary. This water can be present in the polymerization system, or can be added after the polymerization solution has been extracted from the system and subjected to the separation step. When obtaining a polymer in the form of particles from a polymerization system, for example, JP-A-1-1
A preferred method is as shown in No. 10533, in which polymerization is carried out in the presence of a certain amount of water and the polymer is precipitated into particles by slow cooling.

[0011] Separation of the polymer in the present invention is carried out by filtration or centrifugation from a water-containing slurry; high temperatures above 120°C are unfavorable due to water evaporation, and low temperatures below 30°C are unfavorable. This is not preferable because the oligomer elution efficiency is poor. In the most preferred embodiment of the present invention, a slurry polymerized in a water-N alkyl lactam mixed solvent is directly poured into a certain amount of N alkyl lactam to prepare a homogeneous slurry, and at the same time, oligomer components are extracted and the polymer is filtered. This is a different method.

At this time, in view of improving the extraction efficiency of oligomers and the yield of polymers, the molar ratio of water to N alkyl lactam in the slurry immediately before filtration is 0.3:1 to 2:1, and N
It is necessary to adjust the ratio of alkyl lactam to polymer to 10:1 to 50:1, and if it is outside this range, the yield will decrease due to dissolution of the polymer and insufficient extraction of the oligomer will occur, which is undesirable. Therefore, if the amount of N-alkyl lactam is small when obtaining the previous reaction mixture, add N-alkyl lactam or reduce the amount of water, and if the amount is large, add water or reduce the amount of N-alkyl lactam. etc. is necessary.

[0013] Oligomer as used in the present invention refers to the amount of acetone extracted in polyphenylene sulfide sulfone. Specifically, the polymer is extracted with acetone using a Soxhlet extractor, and the acetone is evaporated from the extracted acetone solution. This is the amount calculated based on the remaining amount of the polymer. The preferred range of this amount is 2.5% by weight or less, particularly preferably 1.5% or less; if this amount is too large, problems such as changes in viscosity during melting, volatilization of oligomer components, and adhesion may occur, which is not preferred.

In addition, in the present invention, the polymer filtered under certain conditions is further washed with water to remove by-products such as alkali halides. A method of washing under acidic conditions for the purpose of reducing the content of inorganic compounds is effective. The ash content in the present invention means that the polymer is heated at 560°C in a platinum crucible at 6°C.
This refers to the portion that is soluble in dilute hydrochloric acid or dilute nitric acid among the remaining amount after firing for a certain period of time. This preferred range is 0.4% by weight or less, and this amount is related to the conditions for washing the polymer with water, but is greatly influenced by the conditions during filtration in the present invention.

The method for filtering the reaction mixture (slurry) of the present invention is not particularly limited, and examples include conventional vibrating screens, belt filters, filter presses, centrifuges, and the like.

The polyphenylene sulfide sulfone obtained by the present invention can be made into sheets, films,
It can be applied not only to fibers but also to injection molding in combination with various fillers, and can also be blended or alloyed with other organic polymers.

[0017]

[Operation and Effects of the Invention] The present invention is characterized in that when a polymer is separated from a reaction mixture of polyphenylene sulfide sulfone, it is filtered under certain conditions to reduce the oligomer and ash content. It is a polymer that generates little gas and tar-like substances, has excellent melt stability, and can provide articles with excellent mechanical and electrical properties.

[0018]

[Examples] The present invention will be further explained below by giving examples and comparing with comparative examples, but the scope of the present invention is not limited to these examples.

Example 1, Comparative Example 1 1.00 in 1 liter SUS316 autoclave
Gram moles of sodium bisulfide (47.30%) and 0.
Add 90 mol of caustic soda (48.20%), 0.5 gram mol of sodium acetate anhydride, 0.12 gram mol of sodium carbonate, 8.0 gram mol of N-methylpyrrolidone and seal at 130°C for 3 hours. Heated to the bottom. The system was cooled to 70°C, 1.02 gmol of 4,4'-dichlorodiphenylsulfone was added together with 1.0 gmol of N-methylpyrrolidone, and heated at 260°C for 2 hours at 1°C/min. The mixture was gradually cooled down to 120°C at a rate of . This system was extracted into 3.0 gmol of N-methylpyrrolidone, and the granular polymer was filtered off at 70°C using a 200 mesh wire gauze. At this time, the molar ratio of water to N-methylpyrrolidone was 0.55:1, and the molar ratio of N-methylpyrrolidone to polymer was 12:1.

On the other hand, for comparison, polymerization was carried out in the same manner, and the polymerized system was extracted into 500 ml of water. At this time, the molar ratio of water to N-methylpyrrolidone was 3.8:1, and the molar ratio of N-alkyllactam to polymer was 9:1.

The granular polymers separated by filtration in both processes were washed five times using 500 ml of 70° C. warm water each time, and finally 10 ml of acetic acid was added. Table 1 shows the analysis results of the polymer and the results of melt pressing at 360° C. to form a 200 μm thick film and measuring its physical properties. The melt flow was measured at 343°C under a load of 5 kg, and the ratio of the flow rate after 5 minutes of residence (MF5) to the flow rate after 30 minutes of residence (MF30) was measured as a measure of melt stability. .

For the tensile test, a press film (light yellow transparent) was cut into a 10 mm width sample. Further, the withstand voltage was measured using an electrode with a diameter of 25 mm. The oligomer was determined from the amount of residue obtained by extracting 10 grams of the polymer with acetone using a Soxhlet extractor for 3 hours, and then drying the acetone solution in an oven at 50°C. The ash content was determined by measuring the remaining amount after burning about 3 grams of the polymer in a platinum crucible at 560° C. for 6 hours.

[0023]

[Table 1]

Example 2, Comparative Example 2 A polymer was synthesized in the same manner as in Example 1 and Comparative Example 1.
However, instead of 1.02 gmol of 4,4'-dichlorodiphenylsulfone, 0.95 mole of 4,4'-dichlorodiphenylsulfone and 0.07 mole of 4,4'-dichloro Benzophenone was used. Furthermore, acetic acid was not added during washing. Measurements were carried out on the same items as in Example 1, and the results shown in Table 2 below were obtained, demonstrating that the method of the present invention provides an excellent polymer.

[0025]

[Table 2]

Claims (1)

[Claims] Claim 1: Using an N-alkyl lactam as a solvent, in the presence of an alkali metal carboxylate and/or free water, an alkali metal sulfide and a dihalogen aromatic sulfone are reacted as raw materials, and then cooled to form a reaction mixture. In a method for producing polyphenylene sulfide sulfone in which the polymer is separated by filtration from
2:1, and the molar ratio of N-alkyl lactam to polymer is adjusted to 10:1 to 50:1.