METHOD OF PRODUCING POLYARYLENE SULFIDE

Abstract

A method of producing a polyarylene sulfide (PAS) with a high nitrogen content in the PAS, the method thereof improving the characteristics of the PAS while reducing the amount of organic by-products, and using a plurality of reaction vessels that are in communication with each other through a gas phase. In the production method, a supply step, a water removal step, a polymerizing step, and a recovering step are performed in parallel. A polar organic solvent, a sulfur source, and a dihalo aromatic compound are used as reaction raw materials. A supply amount of the polar organic solvent used as a reaction raw material is 5 mol or less per mole of the sulfur source used as a reaction raw material. The polar organic solvent has a bond represented by —RO—N—, where R is C or P.

Claims

1. A method of producing a polyarylene sulfide, the method comprising: a supply step of supplying a polar organic solvent, a sulfur source, and a dihalo aromatic compound as reaction raw materials to at least one of a plurality of reaction vessels communicating with each other through a gas phase; a water removal step of removing at least a portion of water present in the reaction vessels; a polymerizing step of performing a polymerization reaction in the plurality of reaction vessels; a transfer step of sequentially transferring a reaction mixture obtained through the polymerizing step among the reaction vessels; and a recovering step of recovering the reaction mixture; wherein a supply amount of the polar organic solvent is 5 mol or less per 1 mol of the sulfur source; the reaction vessels are within a continuous production apparatus provided with a housing chamber accommodating the plurality of reaction vessels connected in series; the reaction vessels are communicated with each other through a gas phase in the housing chamber; the supply step, the water removal step, the polymerizing step, and the recovering step are performed in parallel; and the polar organic solvent has a bond represented by —RO—N—, where R is C or P.

2. A method of producing a polyarylene sulfide, the method comprising: a supply step of supplying a polar organic solvent, a sulfur source, and a dihalo aromatic compound as reaction raw materials to at least one of a plurality of reaction vessels communicating with each other through a gas phase; a water removal step of removing at least a portion of water present in the reaction vessels; a polymerizing step of performing a polymerization reaction in the plurality of reaction vessels; a transfer step of sequentially transferring a reaction mixture obtained through the polymerizing step among the reaction vessels; and a recovering step of recovering the reaction mixture; wherein a supply amount of the polar organic solvent is 5 mol or less per 1 mol of the sulfur source; the plurality of reaction vessels is connected through a ventilation unit so as to communicate with each other through the gas phase; the reaction vessels adjacent to each other are connected by piping; the supply step, the water removal step, the polymerizing step, and the recovering step are performed in parallel; and the polar organic solvent has a bond represented by —RO—N—, where R is C or P.

3. The method of producing a polyarylene sulfide according to claim 1, wherein the plurality of reaction vessels is connected in order of a high maximum liquid surface level of liquid that can be accommodated in each reaction vessel; and in the transfer step, the reaction mixture is sequentially transferred using a height difference in the maximum liquid surface level.

4. The method of producing a polyarylene sulfide according to claim 1, wherein the supply step, the water removal step, the polymerizing step, the transfer step, and the recovering step are performed in parallel.

5. The method of producing a polyarylene sulfide according to claim 1, wherein the polar organic solvent is a cyclic organic amide solvent; and a value determined by Equation (1) is 4 mol/mol or less:
(A)×(B)/(C)  (1), where in Equation (1), (A) represents a supply amount [mol/mol] of the cyclic organic amide solvent per 1 mol of the sulfur source; (B) represents a produced amount [mmol/mol] of halogenated aromatic aminoalkyl acid per 1 mol of the sulfur source, the halogenated aromatic aminoalkyl acid being produced as an organic by-product in the polymerizing step; and (C) represents a nitrogen content [mmol/mol] contained in the polyarylene sulfide per 1 mol of the sulfur source.

6. The method of producing a polyarylene sulfide according to claim 1, wherein the polar organic solvent is N-alkyl-2-pyrrolidone, and the dihalo aromatic compound is p-dichlorobenzene.

7. The method of producing a polyarylene sulfide according to claim 5, wherein the produced amount of the halogenated aromatic aminoalkyl acid is not greater than 4.3 mmol per 1 mol of the sulfur source.

Description

EXAMPLES

Example 1: Production of PAS

[0073] As the PAS production apparatus, the PAS continuous production apparatus illustrated in FIG. 1 of Patent Document 2 was used. Specifically, the PAS production apparatus was a horizontal-type continuous polymerization apparatus made of titanium with dimensions including a diameter of 100 mm and a length of 300 mm, and having a semi-circular partitioning wall.

[0074] The PAS continuous production apparatus was charged with 950 g of NMP, after which a temperature 1 of a portion demarcated by a second partition wall and a third partition wall from the upstream side was maintained at 250° C., and a temperature 2 of a portion demarcated by the third partition wall and a fourth partition wall was maintained at 260° C., and a constant-flow pump was used to continuously supply raw materials from each supply line including an NMP-pDCB liquid mixture (NMP:pDCB (mass ratio)=1090.2:767.4) supplied at a flow rate of 2.16 g/min, and 36.40 mass % NaSH supplied at a flow rate of 0.91 g/min. Simultaneously, water was continuously removed from the PAS continuous production apparatus using a distillation device connected to the PAS continuous production apparatus while controlling the pressure to a gauge pressure of 0.3 MPa with a pressure adjustment valve, and the pDCB accompanied with the water that was removed was separated with a settler, and the entire amount thereof was returned to the reaction vessel at the upstream side of the first partition wall from the upstream side. The gas from the distillation device was washed with 14.52 mass % NaOH at a rate of 1.62 g/min and with NMP at a rate of 0.50 g/min, and released, the NaOH and NMP being supplied to a gas absorption column. At this time, the total amount of the NMP and NaOH aqueous solution, which had absorbed gas, was supplied to the reaction vessel of the upstream side of the first partition wall from the upstream side.

[0075] In the present example, a supply amount (A) of NMP per 1 mol of the sulfur source (NMP/S) was 3.0 mol/mol, a supply amount of pDCB per 1 mol of the sulfur source (pDCB/S) was 1.03 mol/mol, and a supply amount of NaOH per 1 mol of the sulfur source (NaOH/S) was 1.00 mol/mol.

[0076] Furthermore, during PAS production, the nitrogen flow rate was 0.1 L/min (constantly circulated during polymerization), the average residence time was 4 hours, and the polymer slurry collection time was 1 hour during a period of 8 to 9 hours. The collected polymer slurry was recovered through centrifugation, and the separated and recovered polymer was washed three times with acetone and then washed three times with water. The obtained cake was dried under vacuum at 80° C. for 8 hours, and a PPS powder was obtained. The weight average molecular weight Mw of the PAS powder determined through GPC was 21600.

Example 2: Production of PAS

[0077] PAS was produced in the same manner as in Example 1 with the exception that the supply amount (A) (NMP/S) of NMP per 1 mol of the sulfur source was set to 2.5 mol/mol. The weight average molecular weight Mw of the PAS powder determined through GPC was 18900.

Comparative Example 1: Production of PAS

[0078] PAS was produced in the same manner as in Example 1 with the exception that the supply amount (A) (NMP/S) of NMP per 1 mol of the sulfur source was set to 6.1 mol/mol. The weight average molecular weight Mw of the PAS powder determined through GPC was 21300.

Comparative Example 2: Production of PAS Through Batch-Type Polymerization

[0079] A 1 L titanium autoclave equipped with a stirrer was filled with 504.51 g of NMP, 45.50 g of a 62.16 mass % sodium hydrosulfide solution, and 25.07 g of a 73.27 mass % sodium hydroxide aqueous solution. The supply amount (A) (NMP/S) of NMP per 1 mol of the sulfur source was 10.1 mol/mol.

[0080] The autoclave was further charged with 78.61 g of pDCB and sealed, after which the inside of the autoclave was replaced with nitrogen, and the mixture was heated to 220° C. while stirring. Next, the temperature was increased to 260° C. over 120 minutes, and a polymerization reaction was performed. Subsequently, 27.27 g of water and 1.9 g of 97 mass % sodium hydroxide were mixed, after which the mixture was pumped into the autoclave by a pump, and then the contents inside the autoclave were heated to a temperature of 265° C. and subjected to a polymerization reaction for 2.5 hours while being maintained at that temperature.

[0081] After completion of the reaction, the reaction mixture was cooled to around room temperature, and the reaction solution was passed through a 100-mesh screen. Thus, a granular polymer was separated by sieving. The separated polymer was washed twice with acetone and then washed three times with water. Next, the polymer was washed with 0.3 mass % of an aqueous acetic acid solution, and then washed four times with water. Next, the washed polymer was dried at 105° C. for 13 hours, and a granular PAS was obtained. The weight average molecular weight Mw of the granular PAS determined through GPC was 37100.

Comparative Example 3: Production of PAS Through Batch-Type Polymerization

[0082] PAS was produced in the same manner as in Comparative Example 2 with the exception that the supply amount (A) (NMP/S) of NMP per 1 mol of the sulfur source was set to 3.8 mol/mol. The weight average molecular weight Mw of the granular PAS determined through GPC was 31000.

Comparative Example 4: Production of PAS Through Batch-Type Polymerization

[0083] PAS was produced in the same manner as in Comparative Example 2 with the exception that the supply amount (A) (NMP/S) of NMP per 1 mol of the sulfur source was set to 3.0 mol/mol. The weight average molecular weight Mw of the granular PAS determined through GPC was 31500.

[0084] The polymerization compositions of each of Comparative Examples 2 to 4 are shown in Table 1. In Comparative Examples 3 and 4, water was removed by distillation prior to the polymerization reaction because the desired H.sub.2O/S (amount of H.sub.2O per 1 mol of the sulfur source) was not achieved due to the moisture contained in the raw materials.

TABLE-US-00001 TABLE 1 Compar- Compar- Compar- ative ative ative Example Example Example Batch No. 2 3 4 1st NMP/S (g/mol) 10.1 3.8 3.0 polymer- NaOH/S (mol/mol) 1.00 1.00 1.00 ization p- (mol/mol) 1.060 1.060 1.055 DCB/S 2nd NMP/S (g/mol) 10.1 3.8 3.0 polymer- NaOH/S (mol/mol) 1.06 1.06 1.07 ization p- (mol/mol) 1.060 1.060 1.055 DCB/S

Evaluation Example

[0085] The amount of CPMABA produced in the production of PAS, the nitrogen content in the PAS, and the weight average molecular weight of the PAS were measured as follows for each of Examples 1 and 2 and Comparative Examples 1 to 4.

[0086] <Measurement of CPMABA>

[0087] The slurry-like substance containing PAS after the completion of the polymerization reaction was cooled to room temperature, after which the slurry component was precisely weighed in a volumetric flask. The slurry-like substance when then mixed with a 40 mass % acetonitrile aqueous solution, and then agitated to extract CPMABA. The solution from which the CPMABA was extracted was filtered using a membrane filter. The obtained filtrate was used as a measurement sample and supplied to a high-speed liquid chromatograph (available from Hitachi High-Technologies Corporation, column oven “L-5025”, UV detector “L-4000”), and the content of CPMABA was measured. The synthesized CPMABA was used as the standard substance.

[0088] Furthermore, the produced amount of CPMABA per 1 mol of the sulfur source was calculated.

[0089] <Measurement of Nitrogen Content in PAS>

[0090] The nitrogen content in the PAS (unit: weight ppm) was determined by precisely weighing approximately 1 mg of PAS and subjecting the PAS to elemental analysis using a trace nitrogen and sulfur analyzer (model: ANTEK 7000, available from Astech Corporation).

[0091] <Weight Average Molecular Weight of PAS>

[0092] The weight average molecular weight (Mw) of the polymer was measured under the following conditions using the high-temperature gel permeation chromatograph (GPC) SSC-7101 available from Senshu Scientific, Co., Ltd. The weight average molecular weight was calculated after calibration with polystyrene standards. [0093] Solvent: 1-chloronaphthalene, [0094] Temperature: 210° C. [0095] Detector: UV detector (360 nm) [0096] Sample injection amount: 200 μL (concentration: 0.05 mass %) [0097] Flow rate: 0.7 mL/min [0098] Standard polystyrene: five types of standard polystyrene including 616000, 113000, 26000, 8200, and 600

[0099] The supply amount (A) (NMP/S) of NMP per mole of the sulfur source, the production amount (B) (CPMABA/S) of CPMABA produced per mole of the sulfur source, and the nitrogen content (C) (N amount/S) per mole of the sulfur source contained in the PAS are shown in Table 2 for Examples 1 and 2 and Comparative Examples 1 to 4.

TABLE-US-00002 TABLE 2 Com- Com- Com- Com- parative parative parative parative Exam- Exam- Exam- Exam- Exam- Exam- ple ple ple ple ple ple 1 2 1 2 3 4 Polymerization Con- Con- Con- Batch Batch Batch Form tinuous tinuous tinuous (A) NMP/S 3.0 2.5 6.1 10.1 3.8 3.0 (mol/mol) (B) CPMABA/S 3.45 4.03 4.52 7.92 26.46 36.50 (mmol/mol) (C) 5.17 5.35 5.63 1.95 5.94 7.25 N amount/S (mmol/mol) (A) × (B)/(C) 2.00 1.88 4.90 41.0 16.9 15.1 (mol/mol)

[0100] As shown in Table 2, when the production method of the examples was used, it was possible to maintain a high content of nitrogen in the PAS while suppressing the amount of the organic by-product CPMABA generated.

[0101] On the other hand, with the production method of Comparative Example 1, the high content of nitrogen in the PAS was maintained, but the amount of the generated CPMABA increased compared to the amount that was produced with the production method of the examples. Furthermore, the amount of CPMABA generated was not suppressed with the production method of Comparative Examples 2 to 4.

[0102] Moreover, the values of “(A)×(B)/(C)” in Table 2 show that as the value decreases, the characteristics of the PAS are improved while the amount of organic by-products is reduced. The results also show that productivity is high since the amount of the solvent is low. With the production method of the examples, the values of (A)×(B)/(C) were 4 mol/mol or less, and were all lower than the values of the comparative examples. From these results, it was found that in a comparison with the production method of the comparative examples, a reduction in the amount of organic by-products and an improvement in PAS characteristics can be compatibly achieved while increasing productivity.