PROCESS FOR THE MANUFACTURE OF SULFONATED POLYARLYENE(ETHER) SULFONES

Abstract

A process for the manufacture of a sulfonated polyarylene(ether)sulfone comprising feeding of a solution (S1) comprising a sulfonated polyarylene(ether) sulfone and sulfuric acid into a tooth rim dispersion machine, wherein the solution (S1) is thereby contacted with a liquid (L1) comprising water, particles essentially consisting of a sulfonated polyarylene(ether)sulfone having a foam structure and uses of said particles.

Claims

1.-16. (canceled)

17. A process for the manufacture of a sulfonated polyarylene(ether)sulfone comprising feeding of a solution (S1) comprising a sulfonated polyarylene(ether) sulfone and sulfuric acid into a tooth rim dispersion machine, wherein the solution S1 is thereby contacted with a liquid (L1) comprising water.

18. The process according to claim 17, wherein the liquid L1 comprises water and nitric acid.

19. The process according to claim 17 wherein the liquid L1 has a temperature of from 10 to 25° C., measured prior to initial contact with the solution S1.

20. The process according to claim 17 wherein the tooth rim dispersion machine is operated in recirculation mode.

21. The process according to claim 17 wherein a pump equipped to transport liquids of a viscosity of at least 200 mPas, measured at 65° C. and a shear rate of 10 s.sup.−1 transports the solution S1.

22. The process according to claim 17 wherein the pump is a gear pump.

23. The process according to claim 17, wherein the sulfonated polyarylene(ether)sulfone comprises a building block of general formula (I) ##STR00005## where t and q are each independently 0, 1, 2 or 3, Q, T and Y are each independently a chemical bond or a group selected from —O—, —S—, —SO.sub.2—, S═O, C═O, —N═N— and —CR.sup.aR.sup.b—, where R.sup.a and R.sup.b are each independently a hydrogen atom or a C.sub.1-C.sub.12 alkyl, C.sub.1-C.sub.12 alkoxy or C.sub.6-C.sub.18 aryl group, Ar and Ar.sup.1 are each independently an arylene group having from 6 to 18 carbon atoms and where at least one of the building blocks comprises a phenylene and/or arylene group which is substituted with at least one —SO.sub.2X group and X is C.sub.1 or OZ, where Z is H, Li, Na, K, Mg, Ca or NH.sub.4.

24. The process according to claim 23 wherein the sulfonated polyarylene(ether)sulfone comprises a building block of general formula (II) or (III) or (II) and (III) ##STR00006##

25. The process according to claim 23 wherein the sulfonated polyarylene(ether)sulfone is obtained by reacting a polyarylene(ether)sulfone with a sulfonating agent.

26. Particles obtainable by the process of claim 17, the particles essentially consisting of a sulfonated polyarylene(ether)sulfone having a foam structure.

27. The particles according to claim 26 having less than 20% by weight, based on the weight of the particles, of particles of mesh size below 100 μm, determined by air-jet sieving.

28. The particles according to claim 26 wherein the sulfonated polyarylene(ether)sulfone has a content of free acid of less than 3 mg KOH/g sulfonated polyarylene(ether)sulfone.

29. A solution (S2) comprising the particles according to claim 26 in dissolved form.

30. A process for the manufacture of a binder, coating, film, fiber, membrane or formed article comprising, optionally mixing the solution S2 according to claim 29 with at least one other material, coating, spinning and/or casting the solution S2 or the obtained mixture.

31. Use of the sulfonated polyarylene(ether)sulfone obtained by the process according to claim 17, particles obtained by the process of claim 17, the particles essentially consisting of a sulfonated polyarylene(ether)sulfone having a foam structure or a solution comprising particles in dissolved form, wherein the particles are obtained by the process of claim 17, the particles essentially consisting of a sulfonated polyarylene(ether)sulfone having a foam structure.

32. A binder, coating, film, fiber, membrane or formed article comprising—in a respective processed form, the sulfonated polyarylene(ether)sulfone obtained by the process according to claim 17 or, particles obtainable by the process of claim 17, the particles essentially consisting of a sulfonated polyarylene(ether)sulfone having a foam structure, or a solution comprising particles in dissolved form, wherein the particles are obtained by the process of claim 17, the particles essentially consisting of a sulfonated polyarylene(ether)sulfone having a foam structure, or obtained from a process comprising, optionally mixing a solution comprising particles in dissolved form, wherein the particles are obtained by the process of claim 17, the particles essentially consisting of a sulfonated polyarylene(ether)sulfone having a foam structure with at least one other material, coating, spinning, and/or casting said solution or the obtained mixture

Description

EXAMPLES

Methods

[0120] Bulk Density

[0121] A calibrated cylindric container (e.g. a 250 ml measuring cylinder) was filled loosely with the polymer particles and the weight of the polymer was related to the volume. By gently tapping the container on a solid surface the polymer particles were compacted until a constant volume was reached. This obtained reduced volume was then used for the determination of the bulk density.

[0122] Degree of Sulfonation and Determination of Free Sulfonic Acid

[0123] Two independent titrations were performed.

[0124] In the first titration approx. 1 g polymer (sPES) was dissolved in 5 ml acid free DMF. After complete dissolution, 50 ml 2-propanol were added which resulted in the precipitation of the polymer. The precipitated polymer was removed from the mother-liquor and washed with 2-propanol. The mother liquor and the washings were combined and titrated with 0.1 mol/l tetrabutylammoniumhydroxide solution (TBAH, in methanol/toluene) against a Solvotrode-electrode (Metrohm). Two equivalence points of titration were observed. The first equivalence point (EQP1-1) corresponds to the first of the two protons of the free sulfuric acid and the proton of the sulfonic acid groups of the remainder of the polymer in the mother liquor. The second equivalence point (EQP2-1) corresponds to the second of the two protons of the free sulfuric acid. The TBAH consumption for EQP2-1 is converted into mg KOH and related to the weighed-in amount of polymer (mg KOH/g polymer). 1 ml TBAH solution corresponds to 5.61 mg KOH.

[0125] In the second titration approx. 1 g polymer was dissolved in 50 ml DMF and titrated without any precipitation step. Thus, the complete sulfonic acid groups of the dissolved polymer could be titrated with 0.1 mol/l tetrabutylammoniumhydroxide solution (TBAH, in methanol/toluene). Again, two equivalent points, EQP1-2 and EQP2-2 were observed. The first equivalence point (EQP1-2) corresponds to the first proton of the free sulfuric acid and the proton of the sulfonic acid groups of the polymer. The second equivalence point (EP2-2) corresponds to the second proton of the sulfuric acid and (if any) potentially present phenolic OH endgroups of the sPES. The content of the free sulfonic acid can be determined by deduction of the TBAH consumption for EQP2-1 from the TBAH consumption for EQP1-2. The difference EQP1-2 minus EQP2-1 is converted into mg KOH and related to the weighed-in amount of the polymer. 1 ml TBAH solution corresponds to 5.61 mg KOH.

[0126] Dissolution Time

[0127] The time to dissolve 5 g polymer in 95 g N-methylpyrrolidone which was agitated using a la-boratory shaker with 200 rpm was measured with a stopwatch.

[0128] Fines

[0129] The fines (<100 μm) were measured by air jet sieving. Thereby 40 to 100 g of the respective polymer was placed on a sieve with a mesh size of 100 μm. The fines were blown through the sieve with an air jet (1 bar, 75 m.sup.3/h) for a defined time (10 min). Then the weight of the residual polymer sample on the sieve was measured and the mass lost was determined as the fines.

[0130] Gel Permeation Chromatography/Size Exclusion Chromatography (GPC/SEC)

[0131] The polymer samples were dissolved with a concentration of 4 g/I in DMAc (dimethylacetamide) under addition of 0.5% by weight salt. The obtained solution was filtered with a standard syringe filter with a pore sizes of 0.2 mm. The injection volume was 100 ml at a column temperature off 40° C. The size exclusion chromatography was performed with a combination of several columns. The signals were detected by a differential refractometer (measurement of the refractive index). The calibration was conducted with PMMA-standards with molecular weights, which ranged from M=800 g/mol and M=2.200.000 g/mol.

[0132] Ion Exchange Capacity (Iec) Calculated from KOH

[0133] The ion exchange capacity (iec, in milliequivalent per gram of polymer [meq/g]) can be calculated by division of the sulfonic acid specific KOH consumption [mg/g] as determined by titration by the molar mass of KOH.

iec=KOH−consumption/56,11

[0134] Particle Morphology

[0135] The particle morphology was analyzed by optical microscopy of particles embedded in an epoxy resin and by preparing microtomes.

[0136] Particle Size Distribution

[0137] The particle size distribution was determined by using a Mastersizer 2000 (Malvern Instru-ments). The particles of a sample (approx. 5 g) were dispersed by an air jet (1 bar) and measured by laser diffraction. Then the volume fractions (for example the d.sub.50-value) were evaluated.

[0138] Theoretical Ion Exchange Capacity (Iec)

[0139] The theoretical ion exchange capacity can be calculated as follows:

[00001]$iec=\frac{2*\mathrm{Molfraction}\left(\mathrm{Fig}\text{.3}\right)*1000}{\mathrm{Mn}\left(\mathrm{Fig}\text{.1}\right)*\mathrm{Molfraction}\left(\mathrm{Fig}\text{.1}\right)+\mathrm{Mn}\left(\mathrm{Fig}\text{.3}\right)*\mathrm{Molfraction}\left(\mathrm{Fig}\text{.3}\right)}\left[\mathrm{meq}/g\right]$

[0140] Viscosity Number

[0141] The viscosity number (reduced viscosity; VN) correlates with the molecular weight of the polymers and was measured, based on ISO 1628-5:1998, in a 1% polymer solution in N-methylpyrrolidone. Thereby the eluationtime (t) of a defined volume of the polymer solution in a Ub-belohde 1 C-capillary is related to the running time of the pure solvent (t0) and normalized after-wards with the polymer concentration (c; in g/ml):

VN=[(t/t0)−1]/c[ml/g]

[0142] Copolymer C1

[0143] Copolymer C1 was a non-sulfonated copolymer comprising repeat units of formula lk) and lg) in a molar ratio of 0.95 to 0.05. It was used as starting material for the preparation of sPES-1 to sPES-4.

[0144] On a lab scale the Copolymer C1 was be prepared as follows:

[0145] In a 4 liter glass reactor fitted with a thermometer, a gas inlet tube and a Dean-Stark-trap, 574,34 g (2.00 mol) of 4,4′-dichlorodiphenylsulfone (DCDPS), 475,53 g (1.90 mol) of 4,4′-dihydroxydiphenylsulfone (DHDPS), 18,621 g (0.10 mol) of 4,4′-biphenol and 297,15 g (2.15 mol) of potassium carbonate with a volume average particle size of 33.2 μm were suspended in 1050 ml NMP in a nitrogen atmosphere.

[0146] The mixture was heated to 190° C. within one hour. In the following, the reaction time shall be understood to be the time during which the reaction mixture was maintained at 190° C. The water that was formed in the reaction was continuously removed by distillation. Solvent that evapo-rated was replaced.

[0147] After a reaction time of 7 hours, the reaction was stopped by the addition of 1950 ml NMP and cooling down to room temperature (within one hour). The potassium chloride formed in the reaction was removed by filtration. The obtained copolymer solution was then precipitated in water, the resulting copolymer beads were separated and then extracted with hot water (85° C.) for 20 h. Then the beads were dried at 120° C. for 24 h at reduced pressure (<100 mbar). The presence of the 4,4″-biphenol derived units Ig) in the copolymer can be verified by 1H-NMR-spectroscopy. The obtained copolymer C1 had a glass transition temperature (Tg) of 230.8° C. The viscosity number and the molecular weight (Mn and Mw) are given in Table 1.

Sulfonated Polyarylene(Ether)Sulfone sPES-1 to sPES-4 According to the Invention

[0148] I) Preparation of Solutions S1-1 to S1-4

[0149] From a reservoir sulfuric acid (96-%) was provided to the reaction vessel in an amount needed to provide a solution S1 with the targeted sPES concentration of 8 or 10% by weight. The temperature of the sulfuric acid was set to the sulfonation temperature. 50 kg of copolymer C1 was dosed to the mixture within 10 to 30 minutes. The reaction mixture was stirred for another 90 minutes to completely dissolve the copolymer C1. The reaction mixture was thereafter stirred for another 90 minutes.

[0150] Solutions S1-1 to S1-4 were obtained, comprising sPES-1 to sPES-4 respectively and sulfuric acid. The sulfonation temperature as well as the properties of the solutions S1-1 to S1-4 are given in table 1.

TABLE-US-00002 TABLE 1 Properties of the Solution S1 Concentration of sPES Sulfonation [in % by weight Solution Temperature.sup.a) based on the Viscosity S1 [° C.] solution S1] [mPas] S1-1 45 8 760 S1-2 55 10 1525 S1-3 55 10 1525 S1-4 50 10 1670 .sup.a)The sulfonation temperature equals the temperature at which the solutions S1-1 to S1-4 were fed into the tooth rim dispersion machine used for the experiments

[0151] II) Feeding Solutions S1-1- to S1-4 to the Tooth Rim Dispersion Machine and Contacting it with liquid L1-1 according to the Invention

[0152] In a reservoir equipped with a stirrer and with a wall temperature of 15° C. liquid L1-1 was prepared from 3125 l deionized water and nitric acid so that the nitric acid concentration in the liquid L1-1 was 0.27% by weight, based on the liquid L1-1.

[0153] As tooth rim dispersion machine a one-stage rotor-stator tooth rim dispersion machine with a concave rotor was used (Cavitron® CD1010, with a cone mixing system; Verfahrenstechnik v. Hagen & Funke GmbH, Sprockhövel, Germany).

[0154] The tooth rim dispersion machine device functioned as a pump which due to operating it at maximum rotational speed of 12000 rpm it drew the liquid L1 from the reservoir whereby the inline mixing device was operated in recirculation loop mode.

[0155] While the three-way valve was set to the sulfuric acid reservoir, the gear pump was started to pump the sulfuric acid to the tooth rim dispersion machine and flushing the piping while doing this. After the connecting pipes had been purged by the sulfuric acid, the respective solution S1 was fed to the tooth rim dispersion machine by opening the three-way valve towards the reaction vessel containing the solution S1 and pumping it into the tooth rim dispersion machine.

[0156] Upon the contacting of the respective solution S1 with the liquid L1-1 a suspension was obtained. The suspension was recirculated into the reservoir of liquid L1-1 whereby its solid content increased continually. To avoid settling, the suspension was stirred in the reservoir. The liquid L1 and the suspension respectively were passed through the tooth rim dispersion machine in an amount of about 75 I/min. The temperature of the suspension in the reservoir was monitored. In course of the process the temperature of the suspension rose by between 30 to 35° C. The suspension was recirculated until the respective solution S1 was used up. Thereafter the pipes were purged with the sulfuric acid.

[0157] III) Liquid-Solid Separation and Washing with Liquid L3-1 and Drying

[0158] The suspension was filtered through a Nutsche whereby 1 bar pressure was applied. A filter with a nominal pore size of 10 μm was used. The filter cake was washed with liquid L3-1, whereby it was stirred. As liquid L3-1 about 800 l of deionized water with a temperature of about 40° C. per washing was used. The washing was interrupted as soon as the filtrate water had a pH of 4 or higher. Typically, not more than six washings were carried out. Thereafter, the obtained respective sPES was dried in the Nutsche under vacuum at 55 to 60° C. until a residual water content of below 2% by weight, based on the weight of the sPES was obtained. The obtained sPES particles were collected.

[0159] Table 2 gives the conditions of the feeding of the solutions S1-1 to S1-4 to the tooth rim dispersion machine and the properties of the sPES-1 to sPES-4 obtained as well as of the copolymer C1.

[0160] Table 3 gives the degree of sulfonation as well as the amount of residual free acid of sPES-1 to sPES-4.

[0161] An illustrative embodiment of the process is shown in FIG. 1.

TABLE-US-00003 TABLE 2 Gear pump Viscosity feed of number solution S1 Tg VN Mw Mn PDI [mPas] [kg/min] [° C.] [mPas] [g/mol] [g/mol] Mw/Mn S1-1 760 3.9 sPES-1 86.3 72400 19900 3.6 S1-2 1525 3.7 sPES-2 87.0 73700 20600 3.6 S1-3 1525 4 sPES-3 86.9 77000 24200 3.2 S1-4 1670 3.85 sPES-4 233.4 88.5 77500 22700 3.4 C1 230.8 82.1  74 450.sup.f)  21050 .sup.f) 3.6 Particle Fines size smaller Matrix Bulk Particle Dissolution (d.sub.50) 100 μm Density density Density.sup.c) Porosity.sup.d) Time.sup.e) [μm] [% by wt] [g/cm.sup.3] [g/l] [g/ml] [%] [min] S1-1 546 7 1.402.sup.a) 172 218.sup.b) 0.900 36 9 S1-2 768 3 1.396.sup.a) 179 217.sup.b) 0.720 49 7 S1-3 830 1 1.403.sup.a) 160 188.sup.b) 0.749 46 7 S1-4 859 2 1.398.sup.a) 158 184.sup.b) 0.679 51 7 1.387  1.078 22 About 100 .sup.a)Determined analog DIN EN ISO 1183-3 (Helium Gas Pycnometer) after drying at 80° C. and 100 mbar until constant weight; .sup.b)After vibration compacting till volume constancy .sup.c)Determined in a pycnometer at 25° C. with a low-viscosity paraffin oil after 10 s of treatment in an ultrasonic bath in order to remove adhering air bubbles from the particles .sup.d)Calculated by dividing the particle density by the mean matrix density, using the mean matrix density of S1-1 to S1-4 of 1,400 g/cm.sup.3 .sup.e)Time to obtain a 5% by weight solution of the polymer in NMP at room temperature under shaking .sup.f)Averaged value from two measurements

[0162] Table 2 shows that with higher viscosity of the solution S1 the amount of fines was reduced. In addition, a reduction of solution time was observed. For comparative purposes copolymer C1 was dissolved under the same conditions to yield a 5% by weight solution in NMP. The dissolution time was A about 100 min. Table 2 further shows that during the sulfonation and processing compared to the starting material, copolymer C1, no molecular weight degradation took place and that the molecular weight distribution remained the same. Table 2 further shows that porous particles with a foam structure are obtained.

TABLE-US-00004 TABLE 3 Degree of iec Theoretical sulfonation Theoretical KOH- (calc. from degree of (calc. from Free acid iec consumption KOH) sulfonation iec) [mg sPES [meq/g] [mg/g] [meq/g] [mol-%] [mol-%] KOH/g] sPES-1 0.213 11.8 0.210 5 4.9 0.5 sPES-2 11.5 0.205 4.8 0.6 sPES-3 13.0 0.232 5.4 0.6 sPES-4 11.3 0.201 4.7 0.8

[0163] Table 3 shows that a controlled sulfonation took place and that the degree of sulfonation which could be expected from the molar amounts of the repeat units could be obtained. Table 3 also shows that the residual content of free sulfuric acid was under 3 mg KOH/g polymer.

Comparative Examples sPES-C1 to sPES-C4

[0164] For comparative purposes sulfonation trials were performed according to the procedure described for sPES-1. For the trials all used volumes and weights (including those for the washing) were downscaled by a factor of 10000. The sulfonation time and the method for contacting the obtained solution S1 with the liquid L1-1 were varied.

[0165] sPES-C1 was prepared without additional sulfonation time after copolymer C1 had dissolved (0 min instead of 90 min). The so obtained solution S1-5 was immediately after dissolution poured into the liquid L1-1 equipped with a magnetically coupled high speed agitator instead of the tooth rim dispersion machine. Instead of individual particles a monofilament was formed (see FIG. 5) which had to be cut into small pieces for the washing.

[0166] sPES-C2 was prepared according to the procedure given for the preparation of solution S1-1. The so obtained solution S1-6 was added to the liquid L1-1 dropwise. Typically, 2-5 mm large, mostly spherical, particles which were not porous were obtained (FIG. 6).

[0167] sPES-C3 was prepared according to the procedure given for the preparation of solution S1-1, however instead of copolymer C1 a polyarylene(ether) sulfone homopolymer with repeat units lk (PESU) with a viscosity number of 81.3 ml/g (Ultrason® E 6020P from BASF SE) was used. Solution S1-7 was obtained. After the sulfonation time solution S1-7 was poured into the liquid L1-1 equipped with a magnetically coupled high speed agitator instead of the tooth rim dispersion machine. Instead of individual particles a monofilament was formed which had to be cut into small pieces for the washing.

[0168] sPES-C4 was prepared according to the procedure given for the preparation of solution S1-1, however i) instead of copolymer C1 a polyarylene(ether) sulfone homopolymer with repeat units lk (PESU) with a viscosity number of 81.3 ml/g (Ultrason® E 6020P from BASF SE) was used and ii) the sulfonation time was increased to 24 h. Solution S1-8 was obtained. After the sulfonation time solution S1-8 was poured into the liquid L1-1 equipped with a magnetically coupled high speed agitator instead of the tooth rim dispersion machine. Instead of individual particles a monofilament was formed which had to be cut into small pieces for the washing.

[0169] Six washing cycles with the same contact times and temperatures were applied. The pH of the last washing water was measured.

[0170] Table 4 gives the results of these comparative examples

TABLE-US-00005 TABLE 4 Degree of Sulfonation Method of VN of iec sulfonation time after contacting the starting VN KOH- (calc from (calc from pH of 6.sup.th dissolution S1-5 to S1-8 polymer sPES-C consumption KOH) iec) filtration sPES-C at 45° C. with L1-1 [ml/g] [ml/g] [mg/g] [meq/g) [mol-%] water sPES-C1 0 min Pouring under 82.1 81.5 9.5 0.169 4.0 2.6 high speed stirring sPES-C2 90 min dropwise addition 82.1 83.3 12.2 0.217 5.1 2.2 sPES-C3 90 min Pouring under 81.3 79.6 1.0 0.018 0.4 2.6 high speed stirring sPES-C4 24 h Pouring under 81.3 72.5 6.1 0.109 2.6 2.5 high speed stirring

[0171] Table 4 shows that solutions S1 can be obtained not only from copolymer C1. It also shows that when copolymer C1 is used as starting polymer a higher degree of sulfonation was obtained quicker and that less molecular weight degradation was observed. From the results for sPES-C1 it is evident that sulfonation at 45° C. was mostly completed already after dissolution. At the same time the comparative examples show the advantage of using a tooth rim dispersion machine for instance for the washing efficiency.