Division of a polyarylene ether solution

Abstract

The invention relates to a process for producing polyarylene ether beads from a polyarylene ether solution, comprising the steps of i) dividing the polyarylene ether solution in a division apparatus which is made to vibrate with a frequency of 10 to 1400 Hz to obtain droplets, ii) transferring the droplets into a precipitation bath to form polyarylene ether beads in the precipitation bath which (A) comprises at least one aprotic solvent (component (1)) and at least one protic solvent (component (2)), (B) has a temperature of 0° C. to T.sub.c, where the critical temperature T.sub.c in [° C.] can be determined by the numerical equation T.sub.c=(77−c)/0.58 in which c is the concentration of component (1) in the precipitation bath in [% by weight] and (C) has component (1) in concentrations of 5% by weight to c.sub.c, where the critical concentration c.sub.c in [% by weight] can be determined by the numerical equation c.sub.c=77−0.58*T in which T is the temperature in the precipitation bath in [° C.], where
the percentages by weight are each based on the sum of the percentages by weight of component (1) and of component (2) in the precipitation bath.

Claims

1. A process for producing polyarylene ether beads, the process comprising: i) dividing a polyarylene ether solution in a division apparatus vibrating at a frequency of 10 to 1400 Hz to obtain droplets; and ii) transferring the droplets into a precipitation bath to form polyarylene ether beads, wherein: the precipitation bath satisfies the following conditions (A) the precipitation bath comprises at least one aprotic solvent (component (1)) and at least one protic solvent (component (2)), (B) the precipitation bath has a temperature of 0° C. to T.sub.c, where the critical temperature T.sub.c in [° C.] is determined by the numerical equation T.sub.c=(77−c)/0.58 in which c is the concentration of the component (1) in the precipitation bath in [% by weight], and (C) the precipitation bath has the component (1) in concentrations of 5% by weight to c.sub.c, where the critical concentration c.sub.c in [% by weight] is determined by the numerical equation c.sub.c=77−0.58*T in which T is the temperature in the precipitation bath in [° C.]; percentages by weight are each based on a sum of the percentages by weight of the component (1) and of the component (2) in the precipitation bath; the precipitation bath comprises water, alcohol, or both, as the component (2); the polyarylene ether solution has a concentration of 5 to 50% by weight of polyarylene ether in the at least one aprotic solvent, where percentages by weight are based on a sum of the percentages by weight of the polyarylene ether and the at least one aprotic solvent; the polyarylene ether solution on division has a temperature of 15 to 250° C.; the aprotic solvent is selected from the group consisting of N-methylpyrrolidone, M-ethylpyrrolidone, dimethyl sulfoxide, dimethylformamide, sulfolane, diphenyl sulfone, 1,2-dichlorobenzene, hexamethylphosphoramide and mixtures thereof; and wherein, in the polyarylene ether beads precipitated from the precipitation bath in (ii), a content of particles having a particle size of less than or equal to 1000 μm is 2.1% by weight or less.

2. The process according to claim 1, wherein the precipitation bath is agitated.

3. The process according to claim 1, wherein the polyarylene ether solution on division has a temperature of 20 to 120° C.

4. The process according to claim 1, wherein the polyarylene ether solution after leaving the division apparatus covers a full distance from the exit point to the precipitation bath surface of 0.10 m to 1.20 m.

5. The process according to claim 1, wherein the division apparatus comprises capillaries, die plates, or both.

6. The process according to claim 5, wherein the division apparatus comprises a perforated plate comprising at least one capillary, hole, or both having a diameter of 0.1 to 5.0 mm.

7. The process according to claim 1, wherein the polyarylene ether solution and the precipitation bath comprise the same aprotic solvent.

8. The process according to claim 1, wherein the precipitation bath comprises 12 to 50% by weight, of the component (1), where the percentages by weight are each based on the sum of the percentages by weight of component (1) and component (2) in the precipitation bath.

9. The process according to claim 1, further comprising stirring the precipitation bath when transferring the droplets into the precipitation bath.

10. The process of claim 1, wherein, in the polyarylene ether beads precipitated from the precipitation bath in (ii), the content of particles having a particle size of less than or equal to 1000 μm is 1.3% by weight or less.

11. The process according to claim 1, wherein the polyarylene ether beads are individual beads which are not agglomerated.

Description

EXAMPLES

(1) Experiments 1 to 25 were conducted with various illustrative polyarylene ether solutions, all of which are described in table 1.

(2) The solutions used were adjusted to the respective concentrations.

(3) TABLE-US-00001 TABLE 1 Description of the polyaryl ether solutions. Solution Structure of the Concentration in the number Solvent polyaryl ether solvent [% by wt.] 1 NMP Formula I 21 2 NMP Formula I 17 3 NMP Formula II 16 4 NMP Formula II 18

(4) The viscosity number determination was conducted to ISO1628 from a 0.01 g/ml solution in phenol/1,2-dichlorobenzene (1:1) at 25° C.

(5) ##STR00004##

(6) The polyaryl ether solution, the concentration of which has been adjusted, was run from a reservoir vessel at a constant delivery rate through a capillary for division to form droplets. The experiments were conducted with a capillary as the division apparatus, and it was possible to cause the capillary to oscillate by the use of a vibrator. The capillary diameter, the fall distance from exit from the capillary to the precipitation bath surface and the oscillation parameters were varied, as specified in the tables below.

(7) After the division, the droplet of the respective polymer solution fell into a precipitation bath. The temperature and composition of the precipitation bath were kept constant during an experiment.

(8) The beads formed in the operation were removed with the aid of a sieve. To study the product, the precipitated polymer was extracted with water at a temperature of 95° C. for 20 hours. For this purpose, the beads were introduced into a vessel through which 160 l of water per hour flowed. Subsequently, the beads were dried at 150° C. under reduced pressure for two days.

(9) Various analyses were conducted.

(10) A sieve analysis was conducted with the extracted and dried polyaryl ether sulfone beads. The amount of the product was 40 to 75 g in each case. The beads were weighed and then introduced into a vibrating machine. The vibrating machine consisted of several screens, with the coarser screen arranged higher in each case. The mesh sizes of the screens were: 3.15 mm, 2.5 mm, 2 mm, 1.6 mm, 1.25 mm, 1.0 mm, 0.63 mm, 0.5 mm, 0.4 mm, 0.2 mm. The vibrating machine ran for 15 minutes. Subsequently, the residues on the individual screens were weighed and the weights were added up to determine a particle size distribution.

(11) After extraction for 7 hours, a sample was taken from the extraction vessel and the NMP content in the particles was determined by gas chromatography (GC) analysis.

Examples 1 to 9: Influence of Oscillation

(12) In examples 1 to 7, solution 1 was used. The temperature of the polyaryl ether solution in the division apparatus was 70° C. The precipitation bath consisted of a water/NMP mixture (80% by weight of water/20% by weight of NMP). The temperature of the precipitation bath was kept constant at 35° C. The precipitation height was likewise kept constant at 80 cm.

(13) TABLE-US-00002 NMP content Particle size: Particle size: in particles Vibration of the capillary Capillary Through- Fines fraction Coarse fraction after 7-stage Frequency Amplitude diameter put (particles <1 mm) (particles >2 mm) extraction Ex. Use [Hz] [dbV] [mm] [g/h] % by wt. % by wt. % by wt. 1 no — — 1 1980 3.2 7.6 0.55 2 yes 150 50 1 1974 1.9 0.7 0.35 3 no — — 1 900 0.5 3 n.d. 4 no — — 1 1400 0.6 58.6 n.d. 5 yes 150 50 1 1068 2.1 0.5 n.d. (n.d.: not determined)

(14) Examples 1 and 2 show an improvement in the extractability of the beads by the use of a vibrating division apparatus (the NMP content was reduced by 36% in the polyaryl ether particles).

(15) TABLE-US-00003 NMP content Particle size: Particle size: in particles Vibration of the capillary Capillary Through- Fines fraction Coarse fraction after 7-stage Frequency Amplitude diameter put (particles <0.63 mm) (particles >1.6 mm) extraction Ex. Use [Hz] [dbV] [mm] [g/h] % by wt. % by wt. % by wt. 6 no — — 0.7 1800 0.2 89 0.58 7 yes 187 50 0.7 2020 4.3 0.3 0.25

(16) Examples 6 and 7 show an improvement in the extractability of the beads by the use of a vibrating division apparatus (the NMP content was reduced by 57% in the polyaryl ether particles).

(17) In examples 8 to 10, solution 2 was used. The temperature of the polyaryl ether solution at the capillary was 70° C. The precipitation bath consisted of a water/NMP mixture (80% by weight of water/20% by weight of NMP). The temperature of the precipitation bath was kept constant at 35° C. The precipitation height was likewise kept constant at 80 cm.

(18) TABLE-US-00004 NMP content Particle size: Particle size: in particles Vibration of the capillary Capillary Through- Fines fraction Coarse fraction after 7-stage Frequency Amplitude diameter put (particles <0.63 mm) (particles >1.6 mm) extraction Ex. Use [Hz] [dbV] [mm] [g/h] % by wt. % by wt. % by wt. 8 no — — 0.7 1400 0.4 57 0.0085 9 yes 215 100 0.7 1488 0 19 0.0045

(19) In examples 8 and 9, an improvement in the extractability of the beads was obtained by the production of a narrower particle size distribution (the NMP content was reduced by 47% in the polyaryl ether particles).

Examples 10 to 25: Influence of Precipitation Bath Composition

(20) In examples 10 to 17, solution 3 was used. The temperature of the polyaryl ether solution at the capillary was 70° C. The capillary diameter was 0.7 mm. The precipitation height was kept constant at 80 cm. The throughput was likewise kept constant at 2064 g/h.

(21) Experiments were conducted at different temperatures and composition, as specified in the tables.

(22) The NMP content in the precipitation bath was increased from 20% by weight until the beads present in the precipitation bath agglomerated. Agglomeration of the beads is disadvantageous since such beads cannot be processed any further.

(23) Variation of the NMP content of the precipitation bath at precipitation bath temperature 35° C.:

(24) TABLE-US-00005 Precipitation bath Vibration of the capillary NMP Frequency Amplitude T content Precipitation Ex. Use [Hz] [dbV] [° C.] [% by wt.] characteristics 10 yes 161 100 35 20 Individual beads 11 yes 161 100 35 40 Individual beads 12 yes 161 100 35 50 Individual beads 13 yes 161 100 35 58 Beads which agglomerate in the precipitation bath

(25) Variation of the NMP content of the precipitation bath at precipitation bath temperature 50° C.:

(26) TABLE-US-00006 Precipitation bath Vibration of the capillary NMP Frequency Amplitude T content Precipitation Ex. Use [Hz] [dbV] [° C.] [% by wt.] characteristics 14 yes 161 100 50 20 Individual beads 15 yes 161 100 50 30 Individual beads 16 yes 161 100 50 40 Individual beads 17 yes 161 100 50 50 Beads which agglomerate in the precipitation bath

(27) In examples 18 to 25, solution 4 was used. The temperature of the polyaryl ether solution at the capillary was 70° C. The capillary diameter was 0.7 mm. The precipitation height was kept constant at 80 cm. The throughput was likewise kept constant at 3780 g/h.

(28) The precipitation bath temperature and precipitation bath composition were kept constant within an experiment. Experiments were conducted at different temperatures and composition, as specified in the tables below.

(29) The NMP content in the precipitation bath was increased from 20% by weight until the beads present in the precipitation bath agglomerated. Agglomeration of the beads is disadvantageous since such beads cannot be processed any further.

(30) Variation of the NMP content of the precipitation bath at precipitation bath temperature 35° C.:

(31) TABLE-US-00007 Precipitation bath Vibration of the capillary NMP Frequency Amplitude T content Precipitation Ex. Use [Hz] [dbV] [° C.] [% by wt.] characteristics 18 yes 206 100 35 20 Individual beads 19 yes 206 100 35 40 Individual beads 20 yes 206 100 35 50 Individual beads 21 yes 206 100 35 58 Beads which agglomerate in the precipitation bath

(32) Variation of the NMP content of the precipitation bath at precipitation bath temperature 50° C.:

(33) TABLE-US-00008 Precipitation bath Vibration of the capillary NMP Frequency Amplitude T content Precipitation Ex. Use [Hz] [dbV] [° C.] [% by wt.] characteristics 22 yes 161 100 50 20 Individual beads 23 yes 161 100 50 30 Individual beads 24 yes 161 100 50 40 Individual beads 25 yes 161 100 50 50 Beads which agglomerate in the precipitation bath

(34) Examples 26 to 31 show the influence of the concentration of aprotic solvent in the precipitation bath on the formation of fines. “Fines” are understood here to mean polyarylene ether beads having a particle size of ≦1000 μm.

(35) For this purpose, a solution 5 of polyarylene ether in sulfolane or NMP was prepared. The polyarylene ether used was Ultrason® E2020 from BASF SE. The concentration of the polyarylene ether in sulfolane was 16.0% by weight the concentration of the polyarylene ether in NMP was 18.0% by weight.

(36) The polyarylene ether was precipitated by means of dropletization and then extracted.

(37) For the dropletization, solution 5 was introduced into the reservoir vessel and adjusted to the desired temperature. By means of a gear pump, solution 5 was dropletized through a capillary. The precipitation was effected in a precipitation bath with an overflow to an agitated screen which removed the beads. The precipitation bath solution was collected in a buffer vessel and then sent back to the precipitation bath.

(38) The concentration of NMP or sulfolane in the precipitation bath was monitored by means of refractive index and balanced by addition of demineralized water. After dropletization had ended, the beads/lenses were filtered off with suction, washed with demineralized water and then extracted.

(39) The conditions during the dropletization are specified in the following table:

(40) TABLE-US-00009 Conc. solv. in Precip- Temp. of Conc. the pre- itation solution 5 in solu- cipita- bath on drop- Fall tion 5 tion bath temp. letization height Exp. Solvent [% by wt.] [%] [° C.] [° C.] [cm] 26 NMP 18.0 40 40 40 30 27 NMP 18.0 <1 40 40 30 28 sulfolane 16.0 <1 40 80 60 29 sulfolane 16.0 40 40 80 60

(41) The conditions in the extraction with water were as follows:

(42) The extracted moist beads/lenses were dried in a drying cabinet at 60° C. and then the distribution was determined by means of manual screening in a screening tower. The results are reported in the table which follows.

(43) TABLE-US-00010 Particle size [μm] 28 29 26 27 3150 99.16 100.0 100.0 99.80 2800 97.49 99.89 99.78 99.01 2500 92.48 99.21 98.49 97.43 2000 27.69 30.51 54.96 30.56 1600 8.88 2.94 8.62 5.84 1250 5.33 0.45 3.45 2.67 1000 4.28 0.23 1.08 1.68  650 3.87 0.45 0.22 0.69 Sum ≦1000 = 8.15 0.68 1.3 2.37 fines

(44) Examples 30 and 31 were conducted analogously to examples 26 to 29. The fall height and the temperature were altered; the concentration of the precipitation bath was varied. The results are reported in the table which follows.

(45) TABLE-US-00011 Precipitation bath PES soln. Fall Fines frac- Conc. NMP Temp. SC Temp. height tion <1 mm Exp. [%] [° C.] [%] [° C.] [cm] [%] 30 20 35 23 65 90 0.37 31 1 35 23 65 90 0.93

(46) Examples 26 to 31 show that, within the inventive concentration range of aprotic solvent in the precipitation bath, polyarylene ether beads having a distinctly smaller fines fraction are obtained.