KR960007343B1 - Process for preparing polyarylene sulfides - Google Patents

Abstract

The polyarylene sulfide of low Mw is firstly synthesized by reacting p-dihalobenzene and alkali metal sulfide in a mole ratio of 0.5-2:1 in a polar organic solvent for 1-8hrs. at 220-270deg.C. The polyarylene sulfide of high Mw is secondly synthesized the by polymerizing the first resulting cpd., p-dihalobenzene, alkali metal sulfide and 0.005-0.5 of mole alkali metal carboxylate based on one mole of the alkali metal sulfide at the same reaction condn.

Description

Process for preparing high molecular weight polyarylene sulfide

The present invention relates to a method for producing a polyarylene sulfide having a high molecular weight. Polyarylene sulfide is a material used for molding members, films and fibers because of its excellent heat resistance and chemical resistance, and is generally manufactured by reacting para-dihalobenzene and alkali metal sulfide in a polar solvent (US Patent No. 3,790,536, Japanese Patent Publication No. 45-3368).

However, since the polyarylene sulfide prepared by this method is extremely low molecular weight and has a low melt viscosity, it is unsuitable for extrusion, so that a method of using a trivalent or higher polyhalo aromatic compound as a crosslinking agent or a branching agent during polymerization is preferred. It is proposed (Japanese Patent Laid-Open No. 53-136100).

Of course, according to the above method, it is possible to easily obtain a high molecular weight of tens of thousands of poises, but because it is a highly crosslinked or branched polymer, it is difficult to process into fibers, films, etc. There is a problem that is extremely vulnerable.

Therefore, the present inventors have proposed this invention as a result of earnestly researching a method for solving such a problem and maintaining the excellent physical properties inherent in polyarylene sulfide.

Hereinafter will be described in detail the contents of the present invention.

In the present invention, para-dihalobenzene, alkali metal sulfide and alkali metal carboxylate are added to the polymer obtained by a known method of reacting para-dihalobenzene and alkali metal sulfide in a polar organic solvent. It is characterized by superpolymerization.

In practicing the present invention, the primary polymerization molar ratio of para-dihalobenzene and alkali metal sulfide is suitably 0.5 to 2: 1, and the amount of polar organic solvent is in the range of 100 to 3000 grams per gram mole of alkali metal sulfide. Is suitable.

In addition, the alkali metal carboxylate used in the secondary polymerization is preferably added in an amount of 0.005 to 0.5 moles with respect to 1 mole of the alkali metal sulfide added in the secondary polymerization. This is not a matter of effectiveness, but a cost increase factor.

In the present invention, the first reaction temperature is 220 to 270 ° C, and the reaction time is suitably 1 hour to 8 hours. The low molecular weight polymer produced under such conditions is filtered to filter out a portion of the solvent and by-products, washed several times with distilled water at about 80 ° C, and dried in a vacuum dryer at about 110 ° C for at least one day.

The amount of para-dichlorololbenzene and alkali metal sulfide to which the second polymerization reaction is newly introduced is in the same molar ratio as the first reaction, but 0.0001 to 100 moles of alkali metal sulfide per 1 mole of the low molecular weight polymer obtained in the first reaction. It is supposed to add a feed.

If the amount is less than 0.0001 mole, the degree of polymerization cannot be increased. If the amount is more than 100 mole, the amount of other additives increases, which is not preferable in terms of cost.

In the present invention, the temperature, time, purification and drying conditions of the secondary reaction may be the same as those of the primary reaction.

The polymer prepared according to the present invention has high molecular weight, which is suitable for pressure and injection of fibers and films, and can exhibit chemical resistance, flame retardancy, and heat resistance, which are inherent in polyarylene sulfide. It is useful for various molding applications.

In the following Examples, the above-mentioned effects are clearly shown.

In this Example, the degree of polymerization was evaluated by melt viscosity, the melt viscosity was measured at 310 ℃ using a Capillary Rheometer (Capillary Rheometer). Standard measurement conditions were made into shear rate 200 (sec) ^-1 and holding time 5 minutes.

Example 1

Into a 2L high-temperature, high-pressure reactor, 237.6 grams of sodium sulfide trihydrate and 1000 grams of N-methyl-2-pyrrolidone were added and dehydrated while slowly heating to 202 ° C (140.5 grams of effluent).

After cooling to 100 캜, 264.6 grams of para-tichlorobenzene was dissolved in 65.0 grams of N-methyl-2-pyrrolidone, and the mixture was heated and sealed at a high temperature and high pressure reactor. Let's do it. After completion of the reaction, the reaction mixture was cooled and the reaction mixture was filtered, and the filtered solid was washed three times with 1000 grams of 80 ° C. middle water, followed by vacuum and drying at 110 ° C. for 1 day. Thus, 171.0 grams (yield 88%) of polyarylene sulfides of melt viscosity 76 Poise were obtained.

150 grams of low-polymerization polyphenylene sulfide was put back into the reactor, and 87.5 grams of para-dichlorobenzene, 99.4 grams of sodium sulfide, 6.1 grams of lithium acetate dihydrate and 1000 grams of N-methyl-2-pyrrolidone were sealed. Then, it heats up to 260 degreeC and makes it react for 5 hours. After completion of the second polymerization, washing and drying in the same manner as in the first polymerization yielded 199.3 grams (yield 93%) of polyphenyl sulfide having a melt viscosity of 670 Poise.

Example 2

2L High temperature, high pressure reactor 238.9 g of sodium sulfide trihydrate and 1000 g of N-methyl-2-pyrrolidone were added and dehydrated while heating slowly to 202 ° C. (152.0 g of effluent).

After the temperature of the contents was cooled to 100 ° C, 264.6 grams of para-dichlorobenzene was dissolved in 65.0 grams of N-methyl-2-pyrrolidone, and the reactor was sealed. The reactor was sealed and then heated to 260 ° C for 5 hours. After completion of the reaction, the reaction mixture was cooled and filtered, and the filtered solid was washed three times with 100 grams of distilled water at 80 ° C., followed by vacuum drying at 110 ° C. for 1 day. 150 grams of 165.2 grams (85% yield) of polyphenyl sulfide having a melt viscosity of 76 Poise thus obtained was put back into the reactor, 10.7 grams of para-dichlorobenzene, 12.3 grams of sodium sulfide, 1.23 grams of sodium acetate, and N-methyl- 1000 grams of 2-pyrrolidone was added and sealed, and the temperature was raised to 260 ° C., followed by reaction for 5 hours. After completion of the second polymerization, washing and drying in the same manner as in the first polymerization yielded 153.2 grams (yield 97%) of polyphenyl sulfide having a melt viscosity of 1800 Poise.

[Comparative Example]

2L high temperature, high pressure reactor, 237.6 grams of sodium sulfide trihydrate, 1000 grams of N-methyl-2-pyrrolidone and 183.4 grams of lithium acetate dihydrate are added and dehydrated while heating slowly to 202 ° C (190.5 grams of effluent).

After cooling to 100 ° C. at room temperature, 264.6 grams of para-dichlorobenzene was dissolved in 70.0 grams of N-methyl-2-pyrrolidone, and the reactor was sealed, and then heated to 260 ° C. and reacted for 5 hours.

After completion of the reaction, the reaction mixture was filtered, and the filtered solid was washed three times with 1000 grams of distilled water at 80 ° C. three times, and then vacuum dried at 110 ° C. for one day. Is obtained.

Claims (2)

Para-dihalobenzenes and alkyllimetal sulfides are reacted in a polar organic solvent to obtain low molecular weight polyarylene sulfides, and then low-molecular weight polyarylene sulfides are again used as para-dihalobenzenes, alkyllimetal sulfides, and A method for producing a high molecular weight polyarylene sulfide, wherein an alkali metal carboxylate is added and secondary polymerization is carried out in a polar solvent. The method of claim 1, wherein the molar ratio of para-dihalobenzene and alkylimide metal sulfide in the primary and secondary polymerization is 0.5 to 2: 1, the alkali metal carboxylate is an alkali metal additionally added in the secondary polymerization High molecular weight polyarylene sulfide, characterized in that 0.005 to 0.5 mole is added per 1 mole of sulfide, and the amount of alkali metal sulfide added during the second polymerization is 0.001 to 100 mole with respect to 1 mole of the first polymerization product. Manufacturing method.