Source: http://www.google.com/patents/US4690766?dq=6650327
Timestamp: 2014-03-17 09:33:23
Document Index: 312139390

Matched Legal Cases: ['Application No. 2027614', 'Application No. 0', 'Application No. 0', 'Application No. 2', 'Application No. 2', 'Application No. 0']

Patent US4690766 - Chemically modified semipermeable polysulfone membranes and their use in ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsSemipermeable membranes of modified polysulfones are provided which comprises repeating units of the formula --M.sub.1 --R.sub.1 --M.sub.2 --R.sub.2 --SO.sub.2 --R.sub.3 --(1) wherein M.sub.1 and M.sub.2 are independently a valence bond, --O-- or --NH--, R.sub.1 is a valence bond or a group of the formula...http://www.google.com/patents/US4690766?utm_source=gb-gplus-sharePatent US4690766 - Chemically modified semipermeable polysulfone membranes and their use in reverse osmosis and ultrafiltrationAdvanced Patent SearchPublication numberUS4690766 APublication typeGrantApplication numberUS 06/757,911Publication dateSep 1, 1987Filing dateJul 22, 1985Priority dateMar 17, 1981Fee statusLapsedAlso published asCA1171614A1, DE3272968D1, EP0061424A2, EP0061424A3, EP0061424B1, US4690765Publication number06757911, 757911, US 4690766 A, US 4690766A, US-A-4690766, US4690766 A, US4690766AInventorsGershon Aviv, Reuven Kotraro, Charles Linder, Mordechai PerryOriginal AssigneeAligena AgExport CitationBiBTeX, EndNote, RefManPatent Citations (6), Referenced by (43), Classifications (35), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetChemically modified semipermeable polysulfone membranes and their use in reverse osmosis and ultrafiltrationUS 4690766 AAbstract Semipermeable membranes of modified polysulfones are provided which comprises repeating units of the formula
wherein M.sub.1 and M.sub.2 are independently a valence bond, --O-- or --NH--, R.sub.1 is a valence bond or a group of the formula ##STR1## with the proviso that if R.sub.1 is a valence bond, only one of M.sub.1 and M.sub.2 can be --O--, R.sub.2 and R.sub.3 are independently a group of the formula ##STR2## the aryl radicals R.sub.1, R.sub.2 and R.sub.3 are optionally further substituted, R.sub.4 is a valence bond, --O--, alkylene of 1 to 4 carbon atoms optionally substituted or interrupted by cycloalkyl(ene) or aryl(ene) of at most 7 carbon atoms, or alkylidene of 2 to 4 carbon atoms, R.sub.5 to R.sub.10 are independently hydrogen, or --R.sub.11 NH.sub.2, ##STR3## or --R.sub.13 OH radicals, these radicals being modified through chemical reaction with
(c) a non-ionic or ionic compound containing at least one, preferably two groups capable of reaction with (b),
--R.sub.12 X or --R.sub.13 CHO radicals, modified through chemical reaction with (b) and (c), or --R.sub.13 CN radicals, modified through chemical reaction with hydroxylamine, (a), (b) and (c),
R.sub.11 is a valence bond, --CH.sub.2 --, alkylene or arylene containing oxygen or nitrogen atoms, R.sub.11 ' constitutes the atoms necessary to form a heterocyclic ring condensed with the polymer backbone and X is halogen, the degree of substitution of substituents R.sub.5 to R.sub.10 --different from hydrogen--being between 0.3 and 3 milliequivalents/g.
We claim: 1. A semipermeable membrane of a modified polysulfone which comprises repeating units of the formula --M.sub.1 --R.sub.1 --M.sub.2 --R.sub.2 --SO.sub.2 --R.sub.3 --(1) wherein M.sub.1 and M.sub.2 are independently a valence bond, --O-- or --NH--, R.sub.1 is a valence bond or a group of the formula ##STR38## with the proviso that if R.sub.1 is a valence bond, only one of M.sub.1 and M.sub.2 can be --O--, R.sub.2 and R.sub.3 are independently a group of the formula ##STR39## the aryl groups of R.sub.1, R.sub.2 and R.sub.3 are optionally further substituted by alkyl of 1 to 4 carbon atoms, R.sub.4 is a valence bond, --O--, alkylene of 1 to 4 carbon atoms optionally substituted or interrupted by cycloalkyl(ene) of aryl(ene) of at most 7 carbon atoms, or alkylidene of 2 to 4 carbon atoms, R.sub.5 to R.sub.10 are independently hydrogen, or --R.sub.11 NH.sub.2, ##STR40## or --R.sub.13 OH radicals, these radicals being modified through a sequence of chemical reactions consisting essentially of steps (a) to (c), wherein: step (a) is reacting said radicals with a monomeric compound containing at least two functional groups, to bond the --R.sub.11 NH--, ##STR41## or --R.sub.13 O-- of said radicals to one of the functional groups of the monomeric compound, step (b) is reacting a product of step (a) with a polyfunctional, linear or branched oligomer or polymer, to bond an available functional group of the monomeric compound to one of the functional groups of the oligomer or polymer and step (c) is reacting a product of step (b) with a non-ionic or ionic compound containing at least one group capable of reaction with the product of step (b), to bond the non-ionic or ionic compound to the product of step (b), --R.sub.12 X or --R.sub.13 CHO radicals, modified through a sequence of chemical reactions consisting essentially of steps (b) and (c), or --R.sub.13 CN radicals, modified through a sequence of chemical reactions consisting essentially of reacting said --R.sub.13 CN radicals with hydroxylamine to form an amidoxime group, followed by steps (a), (b) and (c), R.sub.11 is a valence bond, --CH.sub.2 --, --(CH.sub.2).sub.p NH(CH.sub.2).sub.2-6, --(CH.sub.2).sub.p --O--(CH.sub.2).sub.2-6, ##STR42## R'.sub.11 constitutes atoms necessary to form an imidazolone ring condensed with a polymer backbone consisting of the repeating units of the formula (1), R.sub.12 is --C.sub.n H.sub.2n, R.sub.13 is a valence bond or --C.sub.m H.sub.2m, Y is --O--, --SO.sub.2 -- or ##STR43## X is halogen, m is an integer of 1 to 5 and n is an integer of 1 to 6, p is zero of 1, wherein said membrane contains at least one radical selected from the group consisting of --R.sub.11 NH--, ##STR44## --R.sub.12 --, --R.sub.13 O--, --R.sub.13 CH═ and ##STR45## a degree of substitution of substituents R.sub.5 to R.sub.10 --different from hydrogen--being between 0.3 and 3.5 milliequivalents/g. 2. A membrane according to claim 1, wherein the modified polysulfone comprises repeating units of the formula --M.sub.1 --R.sub.1 --M.sub.2 --R.sub.2 --SO.sub.2 --R.sub.3 --, (2) wherein M.sub.1 and M.sub.2 are --O-- or --NH-- and R.sub.1, R.sub.2 and R.sub.3 have the meanings indicated in claim 1. 3. A membrane according to claim 2, wherein the modified polysulfone comprises repeating units of the formula --O--R.sub.1 --O--R.sub.2 --SO.sub.2 --R.sub.3 --          (5) wherein ##STR46## R.sub.2 and R.sub.3 are independently ##STR47## R.sub.4 ' is a valence bond or alkylene of 1 to 4 carbon atoms, R.sub.51 to R.sub.101 are independently hydrogen or --CH.sub.2 NH.sub.2, --CH.sub.2 OH or --NH.sub.2 radicals, modified through chemical reaction by steps (a), (b), and (c), --CH.sub.2 X radicals, wherein X is halogen, modified through chemical reaction by steps (b) and (c), or --CH.sub.2 CN radicals, modified through chemical reaction with hydroxylamine, and by steps (a), (b) and (c), the degree of substitution of substituents R.sub.51 to R.sub.101 --different from hydrogen--being between 0.3 and 3.5 milliequivalents/g. 4. A membrane according to claim 3, wherein the polysulfone has repeating units of the formula ##STR48## wherein R.sub.61 and R.sub.71 have the meaning indicated in claim 3 and the degree of substitution of substituents R.sub.61 and R.sub.71 --different from hydrogen--being 0.3 to 3.5 meq/g.
5. A membrane according to claim 4, wherein R.sub.61 and/or R.sub.71 comprises --CH.sub.2 NH.sub.2 groups, modified through a sequence of chemical reactions consisting essentially of (a), (b) and (c), whereinin step (a) said monomeric compound is an organic compound that contains reactive multiple bonds or epoxide, aziridine, aldehyde, imidate, isocyanate, isothiocyanate, hydroxyl, anhydride, acyl halide, carbonic acid imide halide or N-methylol groups, or is a compound containing substituents detachable as tertiary amines or as anions, or is a compound containing a combination of these groups and/or substituents, in step (b) said oligomer or polymer is a hydrophilic polyfunctional, aliphatic or aromatic oligomer or polymer containing amino, hydroxyl or thiol groups, and in step (c) said ionic compound contains at least one sulfonic acid group, or carboxylic group, optionally in the form of their salts, or ammonium group, --CH.sub.2 X groups, wherein X is halogen, modified through chemical reaction by steps (b) and (c), or --CH.sub.2 CN groups, modified through chemical reaction with hydroxylamine and by steps (a), (b) and (c). 6. A membrane according to claim 5, wherein said monomeric compound is a cyclic carbonic acid imide halide or a compound containing isocyanate, isothiocyanate or N-methylol groups.
7. A membrane according to claim 6, wherein said monomeric compound is a halogenodiazine or -triazine containing at least 2 reactive substituents and optionally ionic groups.
8. A membrane according to claim 7, wherein said monomeric compound is cyanuric chloride or tetrachloropyrimidine.
9. A membrane according to claim 5, wherein said oligomer or polymer comprises a member selected from the group consisting of polyethyleneimines, polyvinyl alcohols, cellulose derivatives, polyvinylamines, polyvinylanilines, polydialkylamines, amino modified polyepihalohydrines, condensation products of dicyandiamide, amine (ammonium) salts and formaldehyde, diamino condensation products of polyanhydrides, aminoalkyl polysulfones or aminoalkyl polyphenylene oxides.
10. A membrane according to claim 5, wherein said ionic compound is a colored compound.
11. A membrane according to claim 10, wherein said ionic compound is a reactive azo dye containing sulfonic acid groups, carboxyl groups and/or ammonium groups.
12. A membrane according to claim 11, wherein said ionic compound is a reactive azo dyestuff containing sulfonic acid (--SO.sub.3 H) or carboxyl (--COOH) groups and as reactive groups monochlorotriazinyl, dichlorotriazinyl, 2,4-dichloropyrimidinyl, vinyl sulfonyl, β-sulfatoethylsulfonyl, β-chloroethylsulfonyl or β-sulfatoethylaminosulfonyl radicals.
13. A membrane according to claim 5, wherein said ionic compound is a colorless compound containing halotriazinyl or halopyrimidyl radicals.
14. A membrane according to claim 5, wherein the compound (c) contains two groups capable of reacting with the product of step (b).
15. A membrane according to claim 1, wherein the modified polysulfone comprises repeating units of the formula --O--R.sub.2 --SO.sub.2 --R.sub.3 --                       (3) wherein R.sub.2 and R.sub.3 have the meanings indicated in claim 1. 16. A membrane according to claim 1, wherein the modified polysulfone comprises repeating units of the formula --R.sub.1 --O--R.sub.2 --SO.sub.2 --R.sub.3 --             (4) wherein R.sub.1, R.sub.2 and R.sub.3 have the meanings indicated in claim 1. 17. A membrane according to claim 1, wherein said non-ionic compound is a colorless non-ionic cyclic carbonic acid imide halide, a dihalide of dicarboxylic acids, a dialdehyde or a trihalide of tricarboxylic acids.
18. A membrane according to claim 1, wherein said modified polysulfone is supported as thin film by a porous support.
19. A membrane according to claim 1, wherein the non-ionic or ionic compound in step (c) contains two groups capable of reaction with the product of step (b).
20. A process for separating components dissolved in a solution which comprises disposing on one side of a semipermeable membrane according to claim 1 a solution with a solute, said solution having an osmotic pressure, and applying a hydraulic pressure against said solution and said membrane, said hydraulic pressure being greater than the osmotic pressure of said solution.
21. A process according to claim 20, which comprises separating monovalent ions of low ionic weight from polyvalent ions of low or relatively high ionic weight and monovalent ions of high ionic weight.
22. A process according to claim 21, wherein organic and metal-organic ionic substances are separated from by-product inorganic salts in a reaction mixture.
23. A process according to claim 22, wherein inorganic salts are separated from organic dyestuffs.
24. A process for purifying a solution with a solute which comprises disposing on one side of a semipermeable membrane according to claim 1 a solution with a solute, said solution having an osmotic pressure, and applying a hydraulic pressure against said solution and said membrane, said hydraulic pressure being greater than the osmotic pressure of said solution.
25. A process according to claim 24, wherein effluents obtained from dye production are purified by separating off dyes.
26. A process for concentrating a solution with a solute which comprises disposing on one side of a semipermeable membrane according to claim 1 a solution with a solute, said solution having an osmotic pressure, and applying a hydraulic pressure against said solution and said membrane, said hydraulic pressure being greater than the osmotic pressure of said solution.
EXAMPLE 1 A polysulfone with repeating units of the formula ##STR26## is chloromethylated: To a solution of 5 g polysulfone in 200 ml methylene chloride, 5 ml chloromethyl methylether and 0.5 ml SnCl.sub.4 are added, and the solution refluxed for 2 hours. After cooling the solution was poured into 500 ml methanol to precipitate the polymer. The polymer was further purified by redissolving in dimethyl formamide (DMF) and precipitating in water. The chloromethyl content is 1.7 meq/g. Likewise the chloromethylation can be carried out according to U.S. Pat. No. 3,984,399 by using paraformaldehyde, hydrochloric gas and zinc chloride.
Membranes of corresponding properties (flux, rejection) are obtained when using instead of polyethyleneimine a condensation product of dicyandiamide, ammonium chloride and formaldehde.
EXAMPLE 2 This example illustrates (1) the affect of PEI of different molecular weights, and (2) a short reaction time of PEI with the chloromethylated product.
A 25% solution in NMP of a chloromethylated polysulfone prepared according in Example 1 with 1.6 meq Cl/g is prepared and a membrane formed on a support as in example 1. Different membrane pieces are then modified as in example 1 with the difference that the PEI of different molecular weights (100, 1200 and 30,000) and the time of reaction of the membrane with a given PEI is 3 minutes at room temperature instead of 5 minutes at 30
EXAMPLE 4 Example 1 is repeated with a chloromethylated polymer with a chloromethyl content of 2.5 meq/g. The flux and rejection characteristics before and after modification are given in Table III.
EXAMPLE 8 Example 1 is repeated using a PEI of molecular weight 100,000 instead of 30,000-40,000. The results are given in Table III.
TABLE IV______________________________________Solute Rejection and Water Flux ofModified membrane of Example 6.                   Flux     RejectionTest Solute  Conc.      l/m.sup.2                             %______________________________________Na.sub.2 SO.sub.4        1%         60       59Toluene Sulfonic        1%         48       50AcidNaCl         1%         65       14Dye of       1.5%       55       99.6formula(108).sup.1Water                   80       --______________________________________ Test conditions: pHvalue 7.5; room temperature, 20 bar. .sup.1 After 100 hours of operation at pH 10, 55 was 99.3%.
The membrane has an initial rejection and flux to a 4% solution of dye of formula (108) at pH of 10, 50 l/m.sup.2.d, respectively. After 2000 bars of continuous operation at the same conditions with periodic cleaning the rejection and the flux are 98.2% and 1200 l/m.sup.2.d.
EXAMPLE 11 Example 4 is repeated using a polymer (instead of PEI) prepared with a diallylamine salt described in Example 1 of GB Patent Application No. 2027614 and having repeating units of: ##STR27## The results are given in Table V.
EXAMPLE 12 Example 4 is repeated using the butylenediamine derivative of polyepichlorohydrin (GB-PS No. 1,558,807) i.e.: ##STR28## in place of PEI (M.W. 30,000-40,000). The results are given in Table V.
EXAMPLE 13 Example 4 is repeated using an amine containing polymer (instead of PEI) described in EP Application No. 0 008945 (Example 1) ##STR29## The results are given in Table V.
(c) aqueous solution containing 10% of polyethyleneimine (M.W. 30,000), pH 8.5 for 10 minutes; washing 2 hours with water then reacting with dye of formula (101) as in Example 1.
EXAMPLE 20 Example 6 is repeated using a 2% cyanuric chloride solution (water/acetone 4:1) at pH 9.0 and 0 15 minutes at 50 (102a). The resultant membrane has a rejection to 1% solutions of sodium sulfate and sodium chloride of 51% and 19% respectively and a flux at 20 bar of 43 and 50 l/m.sup.2.hr respectively.
EXAMPLE 21 A polysulfone with repeating units of the formula ##STR30## and a chloromethyl content of 1.0 meq/g is cast into a membrane and modified by the procedure described in Example 1. The modified membrane has a rejection and flux to test solute containing 0.15% of the dyestuff of formula (109), at 20 bar of 98.5% and 75 l/m.sup.2.hr.
EXAMPLE 22 A polysulfone with repeating units of the formula ##STR31## is prepared by the procedure described in Desalination, 21 (1977), pages 183-194.
A solution containing 15% of the above polymer and 30% LiNO.sub.3 in N-methyl-pyrrolidone is cast on a glass plate, evaporated in an oven at 130 After leaching for 12 hours, the membrane is modified by immersion in a 2% cyanuric chloride solution (water/acetone 4:1) for 10 minutes at 0 C., and a pH of 7.0, then rinsed in ice water for 10 minutes, immersed in a 10% aqueous solution of polyethyleneimine (M.W. 30,000-40,000) for 30 minutes at pH 8.5, and reacted with dye of formula (101) as in Example 1. The rejection and flux (20 bar, 25 dyestuff of formula (108) of the unmodified and modified membranes is 88.4% and 130 l/m.sup.2.hr and 98% and 50 l/m.sup.2.hr respectively. The modified membrane is crosslinking and insoluble in N-methyl-pyrrolidone.
EXAMPLE 23 Example 4 is repeated with the following changes: After the membrane is cast, it is modified by immersion into a 10% diamino butane solution for 4 hours at 50 PEI and reactive dye as in Example 16. The resultant membrane has a rejection and flux to test solute containing 0.15% of the dye of formula (109) of 99% and 80 l/m.sup.2.hr respectively at 20 bar.
EXAMPLE 24 A polysulfone with repeating units of the formula ##STR32## is brominated on the aromatic methyl radical with N-bromosuccinimide (NBS) by the following procedure: 10 g of polysulfone is dissolved in tetrachloroethane to which 12.0 g NBS and 0.5 g benzoyl peroxide are added and the solution is heated to 80 precipitated in methanol, redissolved and reprecipitaed. A 25% NMP solution of the bromomethylated polymer is filtered, cast and modified on a polyester non-woven as described in Example 1. The unmodified and modified membranes had rejection and flux to dye of formula (108) (1500 ppm at 20 bar) of 86% and 110 l/m.sup.2.hr and 98%, 72 l/m.sup.2.hr, respectively.
EXAMPLE 25 A polysulfone with repeating units of the formula ##STR33## is synthesized by a procedure described in Desalination 21 (1977) pages 183-194. A 25% NMP solution is prepared, filtered, cast on a non-woven support and modified according to the procedure in Example 22. The modified membrane has a rejection of 99.2% to dye of formula (108).
EXAMPLE 26 A polysulfone with repeating units of the formula ##STR34## is prepared by the following procedure: To a stirred solution of 40 moles of non-alkylhalogenated polysulfone (P-1700 of Union Carbide Corp.) in 300 ml dry tetrahydrofuran (THF), a solution of 44 moles of n-BuLi is dropped at 0 the temperature is raised to room temperature and stirring is continued for a further two hours. Then the reaction mixture is cooled with an ice bath and a solution of 1-chloro-4-hydroxy butanol which is protected with dihydropyran in dry THF which is added dropwise. After addition is completed the stirring continues for 5 hours at 5 reaction mixture is refluxed for 2 hours. In order to achieve the chloro alkylated polysulfone 50 ml of thionyl chloride is added in room temperature and the reaction mixture is refluxed for 1 hour. THF and excess of thionyl chloride are evaporated and the polymer is washed thoroughly with water. An n-chloro butyl substitution is obtained.
Reference: G. Schill and E. Logemann, Chem.Ber. pp 106-2919, (1973). H. W. Gschwerd and H. R. Rodriguez, Org. Reaction Vol. 26, p. 62.
EXAMPLE 29 A polymer material of the following structure: ##STR35## was cast into a membrane by the procedure described in Example 1 and modified according to the procedure described in Example 16. The rejection and flux of the unmodified and modified membrane (20 bar, 25 0.15% solution of dyestuff of formula (108)) is 81% and 126 l/m.sup.2.h and 98% and 80 l/m.sup.2.h, respectively.
EXAMPLE 30 A condensate of bisphenolepichlorohydrin with repeating units of the formula ##STR36## is cast from a 15% solution of N-methylpyrrolidone by the procedure of Example 1 and modified by the methods given in Table IX.
EXAMPLE 31 A polybenzimidazole with repeating units of the formula ##STR37## was synthesized according to the procedure described in Preparative Methods of Polymeric Chemistry, Sorenson W. R., and Campbell T. W., 2.sup.nd Edition, p. 169, Interscience Publishers. A 16% solution in dimethylacetamide is cast on a glass plate and immersed after an evaporation step of 15 minutes into a water dimethylacetamide (3:1) bath at 4 and modified according to Example 16. The rejection and flux to test solute containing 1.5% of dye of formula (110) is 96% and 40 l/m.sup.2.h at 20 bar.
Thin film composites have been described for RO membranes. In effect microporous or ultrafiltration (UF) supports are coated with hydrophilic materials and crosslinked with hydrophobic crosslinking agents adsorbed (U.S. Pat. No. 4,125,462), or coated and crosslinked with hydrophobic crosslinking agents for salt rejecting (RO) membranes (EP Application No. 0 008 945, U.S. Pat. No. 3,951,815, GB-PS Pat. No. 1,558,807, GB Patent Application No. 2,027,614 A, U.S. Pat. No. 4,039,440). A cardinal principle of this approach is that during fabrication both the crosslinking agent and its solvent are water insoluble and do not dissolve the thin layer. The said layer may vary in thickness between 1000 to 10000 Å, but is preferably between 2000 to 8000 Å. The attachment of the thin layer to the support relies on physical or mechanical attachment (such as partial penetration into the pores of the substrate). Thus, peeling or detachment is possible and is known to occur. In addition, the support systems are generally made of polymers (polysulfones, polyvinylidene fluorides, and polycarbonates) which are solvent sensitive and may dissolve in non-aqueous solvents.
wherein M.sub.1 and M.sub.2 are independently a valence bond, --O-- or --NH--, R.sub.1 is a valence bond or a group of the formula ##STR4## with the proviso that if R.sub.1 is a valence bond, (M.sub.1 and M.sub.2 have the indicated meanings but) only one of M.sub.1 and M.sub.2 can be --O--, R.sub.2 and R.sub.3 are independently a group of the formula ##STR5## the aryl radicals R.sub.1, R.sub.2 and R.sub.3 are optionally further substituted by alkyl of 1 to 4 carbon atoms, R.sub.4 is a valence bond, --O--, alkylene of 1 to 4 carbon atoms optionally substituted or interrupted by cycloalkyl(ene) or aryl(ene) of at most 7 carbon atoms, or alkylidene of 2 to 4 carbon atoms, R.sub.5 to R.sub.10 are independently hydrogen, or --R.sub.11 NH.sub.2, ##STR6## or --R.sub.13 OH radicals, these radicals being modified through chemical reaction with
R.sub.11 is a valence bond, --CH.sub.2 --, --CH.sub.2).sub.p NH(CH.sub.2).sub.2-6, --(CH.sub.2).sub.p --O(CH.sub.2).sub.2-6, ##STR7## R.sub.11 ' constitutes the atoms necessary to form a heterocyclic ring condensed with the polymer backbone, R.sub.12 is --C.sub.n H.sub.2n, R.sub.13 is a valence bond or --C.sub.m H.sub.2m --, Y is --O--, --SO.sub.2 -- or ##STR8## X is halogen, m is an integer of 1 to 5 and n is an integer of 1 to 6, p is zero or 1, the degree of substitution of substituents R.sub.5 to R.sub.10 --different from hydrogen--being between 0.3 and 3.5 milliequivalents/g.
The present invention may be used to modify ultrafiltration or microporous membranes, with average pore sizes varying from 10 to 5000 Å. The preferred range, however, is 10 to 1000 Å and mostly preferred 20 to 200 Å for the achhievement of optimum rejection with flux. The average pore size of the inventive (modified) membranes varies from about 1 to 200 Å, preferably 5 to 60 Å and mostly preferred 10 to 30 Å. Aromatic polysulfones are suited for the disclosed invention because they are characterized by chemical (particularly oxidative) and temperature stability have good membrane forming properties and reactive groups may be easily introduced.
Is R.sub.4 alkylene of 1 to 4 carbon atoms it comprises e.g. --CH.sub.2 --, --CH.sub.2 CH.sub.2 --, --CH.sub.2).sub.4 and preferably ##STR9## these bridging members can be substituted or interrupted by cycloalkyl(ene), preferably cyclopentyl(ene) or cyclohexyl(ene), or aryl(ene), especially phenyl(ene) or benzyl(ene).
Preferred meanings of R.sub.4 are the direct bond, --O-- or ##STR10## As preferred alkyl(C.sub.1 -C.sub.4) substituted to the arylene groupings R.sub.1, R.sub.2 and R.sub.3 methyl can be mentioned.
X as halogen is Cl, Br or J, wherein Cl is preferred.
--M.sub.1 --R.sub.1 --M.sub.2 --R.sub.2 --SO.sub.2 --R.sub.3 --, (2)
--O--R.sub.2 --SO.sub.2 --R.sub.3 -- or                    (3)
wherein ##STR11## R.sub.2 and R.sub.3 are independently ##STR12## R.sub.4 ' is a valence bond or alkylene of 1 to 4 carbon atoms, R.sub.51 to R.sub.101 are independently hydrogen or
--CH.sub.2 NH.sub.2, --CH.sub.2 OH or --NH.sub.2 radicals, modified through chemical reaction with (a), (b) and (c),
--CH.sub.2 X radicals, wherein X is halogen, modified through chemical reaction with (b) and (c), or
--CH.sub.2 CN radicals, modified through chemical reaction with hydroxylamine, (a), (b) and (c), the degree of substitution of substituents R.sub.51 to R.sub.101 --different from hydrogen--being between 0.3 and 3.5 milliequivalents/g.
Preferred are those membranes of modified polysulfones with repeating units of the formula ##STR13## wherein R.sub.61 and R.sub.71 have the meaning indicated above and their degree of substitution--different from hydrogen--being 0.5 to 3.5 milliequivalents/g (meq/g).
Preferred membranes of modified polysulfones with repeating units of formula (6) are those wherein R.sub.61 and R.sub.71 is chloromethyl, the degree of substitution being 0.9 to 2.6 and the chloromethyl group is modified through (b) and (c); (b) being a polyethylene imine, polyvinylamine or a condensation product of dicyandiamide, ammonium chloride and formaldehyde; (c) being a reactive dye containing at least two reactive halogen atoms based on triazinyl or pyrimidyl radicals or a non-coloured derivative which is a triazine or pyrimidine substituted by two reactive halogens.
These polysulfones show e.g. the following repeating units: ##STR14##
Other useful polymers are those with the following repeating units: ##STR15## The aromatic groups of polysulfone allow for the introduction of different reactive functions. The formation of reactive derivatives may be carried out on the monomer unit prior to polymerization, on the polymer prior to dissolving in the casting solvent or in the casting solution itself, or on the final membrane, or via a combination of any of these said procedures. The reactive groups may be further converted to other groups, e.g. --CH.sub.2 Cl→--CH.sub.2 NH.sub.2, which are finally reacted with the coating polymer. In some instances, it is preferably to convert only the groups on the membranes' surfaces or pores leaving the bulk of the membrane with the original groups.
With respect to the foregoing there are however two main methods for manufacturing the inventive membranes: either one casts a so-called unmodified polysulfone onto a support to form a membrane which is then chemically modified or in an alternative route a polysulfone containing "reactive groups" is used in the casting solution to prepare the membrane which is then modified further.
--M.sub.1 --R.sub.1 '--M.sub.2 --R.sub.2 '--SO.sub.2 --R.sub.3 '--(17)
wherein M.sub.1 and M.sub.2 are independently a valence bond, --O-- or --NH--, R.sub.1 ' is a valence bond, a group of the formula ##STR16## with the proviso that--if R.sub.1 ' is a valence bond--only one of M.sub.1 and M.sub.2 can be --O--, R.sub.2 ' and R.sub.3 ' are independently ##STR17## the aryl radicals R.sub.1 ', R.sub.2 ' and R.sub.3 ' are optionally substituted by alkyl of 1 to 4 carbon atoms, R.sub.4 is a valence bond, --O--, alkylene of 1 to 4 carbon atoms, optionally substituted or interrupted by cycloalkyl(ene) or aryl(ene) of at most 7 carbon atoms, or alkylidene of 2 to 4 carbon atoms, on a porous support from a casting solution containing a polar organic solvent or solvent mixture and optionally partial solvents, non-solvents, electrolytes and/or surfactants into a membrane and contacting the (non-gelled) membrane with a liquid which is miscible with the polar solvent but is a non-solvent for the membrane to effect coagulation, and then introducing
(A) --R.sub.11 NH.sub.2 or --R.sub.13 OH radicals into the membrane, which are further modified through chemical reaction with
(c) a non-ionic or ionic-compound containing at least one, preferably two, group(s) capable of reaction with (b),
wherein R.sub.11, R.sub.12, R.sub.13 and X have the indicated meanings; while the other main route comprises casting a solution of a polysulfone with repeating units of the formula
--M.sub.1 --R.sub.1 "--M.sub.2 --R.sub.2 "--SO.sub.2 --R.sub.3 "--(18)
wherein M.sub.1 and M.sub.2 are independently a valence bond, --O-- or --NH--, R.sub.1 ' is a valence bond, a group of the formula ##STR18## with the proviso that--if R.sub.1 " is a valence bond--only one of M.sub.1 and M.sub.2 can be --O--, R.sub.2 " and R.sub.3 " are independently ##STR19## the aryl radicals R.sub.1 ", R.sub.2 " and R.sub.3 " are optionally further substituted by alkyl of 1 to 4 carbon atoms, R.sub.4 is a valence bond, --O--, alkylene of 1 to 4 carbon atoms, optionally substituted or interrupted by cycloalkyl(ene) or aryl(ene) of at most 7 carbon atoms, or alkylidene of 2 to 4 carbon atoms, R.sub.5 ' to R.sub.10 ' are independently hydrogen,
(A) --R.sub.11 NH.sub.2, ##STR20## or --R.sub.13 OH radicals (B) --R.sub.12 X or --R.sub.12 X or --R.sub.13 CHO radicals, or
(C) --R.sub.13 CN radicals, wherein R.sub.11, R.sub.11 ', R.sub.12, R.sub.13 and X have the meanings indicated above, the degree of substitution of substitutents R.sub.5 ' to R.sub.10 '--different from hydrogen--being between 0.3 and 6 milliequivalents/g, on a porous support from a casting solution containing a polar organic solvent or solvent mixture and optionally partial solvents, non-solvents, electrolytes and/or surfactants into a membrane and contacting the (non-gelled) membrane with a liquid which is miscible with the polar solvent but is a non-solvent for the membrane to effect coagulation, and then modifying the membrane by reacting it with
(c) a non-ionic or ionic compound containing at least one, preferably two group(s) capable of reaction with (b), when R.sub.5 ' to R.sub.10 ' have the meanings of (A), with (b) and (c), when R.sub.5 ' to R.sub.10 ' have the meanings of (B), and with hydroxylamine (a), (b) and (c), when R.sub.5 ' to R.sub.10 ' have the meanings of (C).
Most preferred is the halomethylation e.g. with chloromethyl methylether or by using formaldehyde or paraformaldehyde and hydrochloric gas and/or acid in the presence of a metal catalyst such as zinc chloride (U.S. Pat. No. 3,984,399, Example 2). The chloromethyl (--CH.sub.2 --Cl) group can be easily reacted with ammonia, amines, aminoalcohols, diamines, alkalihydroxides or cyanides to get reactive radicals for further modification which are or which contain as terminal groups amino, hydroxyl, nitrilo or formyl radicals.
Another method of introducing reactive amino functions is the direct amido-methylation described in Tetrahedron Letters 42, 3795-3798, by A. R. Mitchell.
Still another procedure comprises the nitration of the polymer or the membrane (by HNO.sub.3 /H.sub.2 SO.sub.4 solutions) followed by reduction with e.g. sodium dithionite to get --NH.sub.2 groups, which can than be modified by following the reaction sequence (a), (b) and (c).
An important aspect of this invention is the presence of reactive groups, such as amino (primary, secondary amino groups), hydroxyl, cyano, thiocyano, aldehyde, oxirane or vinyl groups or halogen atoms (F, Cl, Br, J) on the starting membrane which can be chemically modified. These reactive groups may be located as substituents on the polymer, or within the backbone itself. The reactive groups may be incorporated into the polymer by the polymerization of monomers already containing the said groups, or may be derived by chemical reactions on the formed polymer. As an example of the latter, halomethyl groups may be readily formed on polysulfone (U.S. Pat. No. 4,029,582), to give: ##STR21## R═-CH.sub.2 X (X═F, Cl, Br, I, preferably Cl or Br).
The halomethyl group may be further converted by well known procedures to: ##STR22## wherein R.sub.a is alkylene (C.sub.2 -C.sub.6) or arylene(phenylene) and X.sub.2 is --CN, --CHO or OH.
An example of the polymerization of a monomer with reactive substituents is 3,3-Dinitro-4,4'-dichlorodiphenyl sulfone which may be condensed with 4,4'-diaminodiphenyl either to give a polymer with repeating units of the formula (Desalination 21, (1977), 183-194) ##STR23## The nitro groups may be reduced to amino groups and further modified to introduce other functions (especially haloalkyls, cyano, hydroxy).
Cyanomethylated functions introduced by CN.sup.⊖ nucleophilic displacement of Cl.sup.⊖ in --CH.sub.2 Cl gives a brittle membrane when the capacity of CN.sup.⊖ is above 1.5 meq/g (suitable range of 0.3 to 1.5 meq/g). If however, the reaction is carried out only on the surface and in the pores of a preformed membrane, the problem of brittleness is decreased. The aldehyde groups can be introduced by treating a chloromethylated polysulfone in dimethylsulfoxide with NaHCO.sub.3 at high temperatures (140 mixture with CHCl.sub.3 and reprecipating the polymer in water (J. M. Frechet, C. Schuerch, JACS 93, 492 (1971)).
The lower limit of functional groups capacity is determined by the minimum concentration needed to crosslink the polymers and to ensure efficient binding for the subsequent reaction to the hydrophilic polymer. This varies with the particular functional group and the molecular weight of the coating polymer. In general, however, a capacity of 0.3 meq/g was found to be the minimum for modification. It is preferred, however, to have a capacity of at least 1.0 meq/g, for efficient modification (0.3 to 3.5, preferably 1.0 to 2.5 meq/g).
When polysulfones with HO-final groups (cf. formulae 10, 14, 15) are used even a lower capacity of functional HO-groups of 0.05 (0.05 to 3.5, preferably 0.1 to 2.5 meq/g) can be sufficient for modification (of special interest when low molecular polysulfones of said formulae are used).
Membrane casting may be performed by any number of casting procedures cited cited in the literature (i.e. U.S. Pat. No. 4,029,582, GB Patent Application No. 2,000,720, U.S. Pat. Nos. 3,556,305, 3,615,024, 3,567,810). Thus, the polymer or its derivative, may be dissolved in a suitable solvent or mixture of solvents (for example, N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), hexamethylphosporamide, N,N-dimethylacetamide, dioxane), which may or may not contain cosolvents, partial solvents, non-solvents, salts, surfactants, or electrolytes, for altering or modifying the membranes morphology and its flux and rejection properties (i.e. acetone, ethanol, methanol, formamide, water, methylethyl ketone, triethyl phosphate, H.sub.2 SO.sub.4, HCl, Tweens, Spans, sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate, sodium hydroxide, potassium hydroxide, potassium chloride, zinc chloride, calcium chloride, lithium nitrate, lithium chloride, magnesium perchlorate etc.).
The polymer casting solution may be applied to the above mentioned substrates by any of the well known techniques, known to those practiced in the art. The wet film thickness may vary between 5μ to 2000μ.
The preferred range being 50μ to 800μ and the most preferred 100 to 500μ. The wet film and support may then be immersed immediately, or after a partial evaporation step (from 5 sec. to 48 hours) at ambient condition or elevated temperature, or vacuum or any combination thereof into a gelling bath of a non solvent. Such baths are usually water, or water with a small percent of a solvent (e.g. DMF, NMP) and/or surfactant (e.g. sodium dodecyl sulfate) at a temperature of 0 C. An example of a commonly used gelling bath is water with 0.5% SDS at 4 containing a component that may be leached out in water or another solvent, is cast and dried before immersion. After immersion, leachable material is removed resulting in a porous membrane. In a third variation, a polymer solution without any leachable materials is cast and taken to dryness, resulting in a porous membrane by virtue of this physicochemical properties of polymeric material--solvent combination or by a subsequent chemical reaction that creates pores. All the above methods may be used to form membranes for further modification as described by this invention. This modification process has several variations but is primarily based on the following sequence that binds a polymer layer to the support membrane and crosslinks this support membrane and polymer film.
(b) Unreacted groups of the multifunctional reagent in step (a) are used to bind a reactive oligomer or polymer to the membrane prepared in step (a). The now bound polymer is a thin film that contains additional unreacted groups for a further reaction with e.g. non-ionics that crosslink the said polymer and/or ionics that additionally introduce charged ionic species in step (c). Functional groups binding to the membranes may or may not be the same as those reacting in the subsequent step.
(c) Ionic (anionic) or hydrophilic (non-ionic) multifunctional reagents are reacted with the functional groups of the bound polymer in step (b) above, thus crosslinking and/or charging the said polymer.
The invention membranes are thus formed by a build-up of a bound hydrophilic oligomer or polymer or poly-electrolyte on the basic membranes' (polysulfone) surface and/or in the pores.
Compounds (a) which can be used as the multifunctional reagents are monomeric, ionic, preferably non-ionic compounds which possess crosslinking properties and can enter into chemical bonding both with the (polysulfone starting) membrane (containing reactive groups) and the coating polymer. These compounds, which have at least two functional groups, possess their reactivity by virtue of reactive multiple bonds, epoxide groups, aziridine groups, aldehyde groups, imidate groups or isocyanate or isothiocyanate groups, further hydroxyl, anhydride, acyl halide, carbonic acid imide halide or N-methylol groups, (these bonds or groups may be further substituted), or of substituents detachable as tertiary amines or preferably as anions, and combinations of these are also possible. The compounds contain, for example, the groupings ##STR24## as a multiple bond to which further substituents can be added on. The isocyanate or isothiocyanate group can also be considered as a group of this type. Component (a) can contain quaternary ammonium groups, which are split off as tertiary amines, for example a trimethylammonium or pyridinium group or sulfonium groups, as the leaving groups. However, component (a) preferably contains substituents with groups that split off as an anion, and preferably containing a reactive halogen atom, as the reactive group. These leaving groups posses their reactivity by virtue of, for example, the influence of electrophilic groups, such as the --CO-- or --SO.sub.2 -- group in saturated aliphatic radicals. They also possess their reactivity by virtue of the influence of a quaternary nitrogen atom, such as in the group .tbd..sup.⊕ NCH.sub.2 CH.sub.2 Cl, or in aromatic radicals by vitrue of the influence of electrophilic groups in the o- and p-position, for example nitro, hydrocarbonsulfonyl or hydrocarboncarbonyl groups, or of the bond to a ring carbon atoms which is adjacent to a tertiary ring nitrogen atom, as in halogenotriazine or halogenopyrimidine radicals.
(A) s-Triazines containing at least two identical or different halogen atoms bonded to carbon atoms, for example cyanuric chloride, cyanuric fluoride, cyanuric bromide and also primary condensation products of cynuric fluoride or cyanuric chloride or cyanuric bromide and, for example, water, ammonia, amines, alkanols, alkylmercaptans, phenols or thiophenols; further of phenols, anilines, alkanols and alkylamines containing ionic groups which will render the dihalogenated triazines water-soluble. Such ionic groups are sulfonic, carboxylic, quaternary ammonium, sulfonium or phosphonium groups.
(B) Pyrimidines containing at least two reactive, identical or different halogen atoms, such as 2,4,6-trichoro-, 2,4,6-trifluoro- or 2,4,6-tribromo-pyrimidine, which can be further substituted in the 5-position, for example by an alkyl, alkenyl, phenyl, carboxyl, cyano, nitro, chloromethyl, chlorovinyl, carbalkoxy, carboxymethyl, alkylsulfonyl, carboxamide or sulfonamide group, but preferably by halogen, for example chlorine, bromine or fluorine. Particularly suitable halogenpyrimidines are 2,4,6-trichloro- and 2,4,5,6-tetrachloro-pyrimidines; water-soluble derivatives of pyrimidines similar to those of (A) above.
(C) Halogenopyimidinecarboxylic acid halides, for example dichloropyrimidine-5- or 6-carboxylic acid chloride;
(H) Anhydrides or halides of aliphatic mono- or di-carboxylic acids having preferably 3 to 10 carbon atoms, or of aromatic carboxylic acids, containing reactive halogen atoms, for example chloroacetyl chloride, β-chloropropionyl chloride, α,β-dibromopropionyl chloride, α-chloro- or β-chloro-acryloyl chloride, chloromaleic anhydride and β-chloro-crotonyl chloride, and fluoro-nitro- or chloro-nitro-benzoic acid halides or -sulfonic acid halides in which the fluorine atom or the chlorine atom is in the o-position and/or p-position relative to the nitro group;
(J) Free or etherified N-methylolureas or N-methylolmelamines, for example N,N-dimethylolurea, N,N-dimethylolurea dimethyl ether, N,N'-dimethylolethylene- or -propylene-urea, 4,5-dihydroxy-N,N'-di-methylolethyleneurea or 4,5-dihydroxy-N,N'-di-methylolethyleneurea dimethyl ether and di- to -hexamethylolmelamine, trimethylolmelamine dimethyl ether, pentamethylolmelamine di- to -trimethyl ether and hexamethylolmelamine pentamethyl or hexamethyl ether;
(K) Condensation products of dialkylalkanes containing at least one phenolic hydroxyl group and halogenhydrins, for example the diepoxide obtained friom 2,2-bis-(4'-hydroxyphenyl)-propane and epichlorohydrin, as well as glycerol triglycidyl ethers and also corresponding diaziridines;
For the reaction of a polysulfone membrane (containing e.g. hydroxyl or amino groups) in step (a) with a multifunctional organic compound it is treated, when e.g. cyanuric chloride is used, with an aqueous (aqueous-organic [acetone]) solution (suspension) of this reagent which (solution) can contain 0.5 to 5 parts of cyanuric chloride per part of membrane. The reaction temperature should be kept below 4 example at 0 chloride; the pH value range is approximately between 8 and 11 and the reaction time can be from 20 minutes to 5 hours.
The sequence of binding the polymer film to the basic membrane (step (b)) is a function of the groups involved. By way of an example however, halomethylated polysulfone will be described. The introduction of halomethyl groups into a polysulfone backbone is readily achieved. In particular chloromethylation of aromatic groups is well documented, (U.S. Pat. No. 4,029,582). The binding of hydrophilic polymers containing amines, or hydroxyl groups can occur via an nucleophilic displacement of the haloatom on the polysulfone membrane. Both binding to and crosslinking of the support occur at this stage. Different catalysts, and solvent combinations may be employed to enhance the reaction. For example a 18% chloromethylated polysulfone (2.0 meq/g) in N-methylpyrrolidone is cast on a support and immersed immediately in ice water. The membrane, after leaching is placed in an aqueous bath of polyethyleneimine (PEI) (M.W. 30,000) containing 1% potassium iodide at 50 membrane is found to be crosslinked and contains a bound layer of PEI for further reaction. Membranes containing aldehyde functions can be modified in an analogous way.
Hydrophilic polymers are used in step (b) to react to and to coat the membrane substrate. The preferred polymers are polyfunctional aliphatic, aromatic or oligomers or polymers heterocyclic which contain amino groups which can be primary, secondary or tertiary. Other alternatively, but less preferred, they may be polymers of hydroxyl or thiofunctions. The aliphatic oligomers or polymers can be acyclic or cyclic ones. Examples of such polymers are polyethyleneimines (M.W. 189-2000,000) which can be partially alkylated or otherwise modified, polyvinylamines (M.W. 1000 to 2,000,000), polyvinyl alcohols (M.W. of 2,000 to 200,000) or partially esterified polyvinyl alcohols, polyvinylanilines, polybenzylamines, polyvinylmercaptans, condensation products of dicyandiamide, amine salts (ammonium chloride) and formaldehyde (U.S. Pat. No. 3,290,310), polymers of 2-hydroxyethyl or 2-amminoethyl-methycrylates, polyvinylimidazolines, amine modified poly-epihalohydrin (described in U.S. Pat. No. 1,558,807), polydiallylamine derivatives and polymers containing piperidine rings (described in GB Pat. No. 2,027,614A), amino polysulphones, amino polyarylene oxides (e.g. amino methylated polyphenylene oxide) and hydrophilic amines containing polymers (described in EP Application No. 0,008,945). The above polymers may be in part a copolymer or a polymer containing other monomeric units, block polymers or graft polymers. If they are copolymers the other monomeric units may or may not contain ionic groups (--SO.sub.3.sup.⊖, --COO.sup.⊖, --N.sup.⊕ R.sub.3).
The preferred polymers are poly aliphatic (acyclic or cyclic) amines. Polyethyleneimine is an example of this group. The range of molecular weights may be between 150(189) to 2,000,000, but preferably between 1000 and 200,000 and most preferred 10,000-70,000. Low molecular weight polymers or oligomers (150 to 1000) may be used but the increase in solute rejection of the final membrane is not as great when higher molecular weight polymers are used.
The molecular weight may also influence the degree of crosslinking. For example, PEI of molecular weight of 30.000 will crosslink a membrane of chlormethylated polysulfone (1.6 meq/g) in 3 minutes at room temperature, while PEI of molecular weight of 189 will not crosslink the membrane under the same conditions. The latter one is still soluble in NMP.
Water is the preferred solvent for the aforementioned molecules, though other solvents such as low molecular weight alcohols or ketones may be used alone or in combination with water. The range of polymer concentration may be from 0.1 to 100%, but preferably between 1 and 30% and most preferred between 5 and 15%. The concentration of polymer needed to achieve optimum rejection/flux characteristics is a function of the reactive groups involved, the temperature, time of immersion, and pH. These factors (together with a rinse step after immersion) control the extent of binding and the thickness of the polymer layer deposited on the membrane. The temperature of the polymer solution during membrane immersion may vary from 0 is a function of the reaction kinetics of the reactants. For example, the reaction of chloromethylated polysulfone with PEI may require a temperature of 30 between chlorotriazinyl groups and PEI is carried out at 25 30 minutes.
The time of immersion may vary between 1 second to 48 hours (preferably 30 seconds to 5 minutes) as a function of the temperature, pH, concentration of reactants and molecular weight of PEI. For example, at a pH of 8.5 and temperature of 50 meq/g) should be immersed between 2 to 12 minutes in 10% PEI (M.W. 30,000) to give high rejection and flux. Longer immersion times may be detrimental to the flux and rejection. An amine containing polymer, after having been reacted with a multifunctional reagent such as cyanuric chloride, need only be immersed in a 10% PEI solution at 20 minutes to achieve a high rejection.
The molecular weight (M.W.) of the PEI can play an important role in the optimization of flux and rejection. If the membrane to be modified has a relatively low rejection (less than 90%) then higher molecular weight PEI (M.W. of about 10,000 to 100,000) are necessary to achieve at least 98% rejection. If, on the other hand, the basic membranes to be modified have greater than 90% rejection, PEI of lower molecular weight (600-9,000) should be used to achieve high rejection (99%) with high flux. Higher molecular weight PEI results in high rejection, but with a corresponding lower flux.
The rinsing solution may also contain solutes, which facilitate the removal of excess hydrophilic polymer and thus shorten the required time of rinsing. Such solutes may be taken from surfactants (anionics and nonionics; sodium diamyl sulfate, dodecylbenzene sulfonic acid, Tweens, etc.), salts, (e.g. sodium carbonate, sodium bicarbonate, sodium sulfate, magnesium chloride, etc.) and non-reactive (intrinsically or under the conditions of reaction) dye molecules e.g. congo red).
Included within the scope of this invention are also hydrophilic multifunctional (non-ionic, colorless) reagents such as low molecular weight difunctional epoxides, aziridines, anhydrides, and preferably a cyclic carbonic acid imide halides (cyanuric chloride or tetrachloropyrimidine), dihalides of dicarboxylic acides, dialdehydes or trihalides of tricarboxylic acids. While many of the above reagents can be applied in aqueous solutions within a narrow range of pH and temperature, the acyl halides must be disolved in aprotic solvents.
The reactive dyes, which can belong to various categories, for example anthraquinone, formazan or preferably azo dyes which are optionally metal complexes. Suitable reactive groups (which are part of the dyes) are the following: carboxylic acid halide groups, sulfonic acid halide groups, radicals of α,β-unsaturated carboxylic acids or amides, for example of acrylic acid, methacrylic acid, α-chloroacrylic acid, α-bromoacrylic acid or acrylamide radicals of preferably low halogenoalkylcarboxylic acids, for example of chloroacetic acid, α,β-dichloropropionic acid or α,β-dibromopropionic acid; radicals or fluorocyclobutanecarboxylic acids, for example of tri- or tetra-fluorocyclobutanecarboxylic acid; radicals containing vinylacyl groups, for example vinylsulfone groups or carboxyvinyl groups; radicals containing ethylsulfonyl (--SO.sub.2 CH.sub.2 CH.sub.2 OSO.sub.2 OH, --SO.sub.2 CH.sub.2 CH.sub.2 Cl) or ethylamino sulfonyl groups (--SO.sub.2 NHCH.sub.2 CH.sub.2 OSO.sub.2 OH) and halogenated heterocyclic radicals such as dihaloquinoxalines, dihalopyridazonyl, dihalophthalazines, halobenzothiazoles and preferably halogenated pyrimidines or 1,3,5-triazines such as monohalotriazines, dihalotriazines, 2,4-dihalopyrimidines or 2,4,6-trihalopyrimidines. Suitable halogen atoms are fluorine, bromine and especially chlorine atoms.
In the two-stage process, the concentration of e.g. a reactive dye (component (c)) in aqueous solution can be about 0.5 to 3%; the adsorption is carried out, for example, at temperatures of 20 C. over a period of 2 to 60 minutes; the pH value can be 4 to 8. Fixing can then be carried out in an aqueous soluion, the pH of which has been adjusted to 9 to 12, and the reaction time can be about 30 minutes. The pH is adjusted to the desired value using any desired inorganic (sodium carbonate) or organic bases.
Depending on the intended application, the membranes can be in various (flat or tubular) forms, for example in the form of sheets, leaves or tubes, or in the form of a pocket, bag, cone or of hollow fibres. When subjected to severe pressure, the membranes can, of course, be protected by non-woven supports, supports made of textile fibres or paper, wire screens or perforated plates and tubes (modules). Within the range indicated further above, the pore size can be varied by means of different temperatures and can likewise be suited to the particular application. Thus, for example, by subjecting the membranes to heat treatment (50 it is possible to change the pore size and thus the flux and the rejection of the membranes.
The amount of the material passed through the membrane per surface and time unit is found to be: ##EQU2## F is appropriately expressed in m.sup.3.m.sup.-2.d.sup.-1, i.e. the number of cubic meters per square meter surface area of the membrane and per day, or in 1 m.sup.-2 h.sup.-1, i.e. liters per square meter surface area of the membrane per hour.
In the following examples, the dyes and colourless compounds of formulae (101) to (107) are used as reactive agents for crosslinking and charging the adsorbed polymer layer, while the dyes of formulae (108) to (110) are used in test solutions. ##STR25##
This application is a continuation of now abandoned application Ser. No. 355,509, filed Mar. 8, 1982 now abandoned.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS3886066 *Nov 6, 1972May 27, 1975Du PontTannin treatment for non-porous semipermeable membranesUS3984399 *Sep 27, 1974Oct 5, 1976Ciba-Geigy AgBis-stilbene compoundsUS4029582 *Jul 7, 1975Jun 14, 1977Daicel, Ltd.Poly(arylether-sulfone) semipermeable membrane comprising substituted halomethyl and/or quaternary nitrogen groupsUS4260652 *Jun 5, 1978Apr 7, 1981Teijin LimitedPreparation of permselective composite membraneUS4286015 *May 1, 1979Aug 25, 1981Asahi Kasei Kogyo Kabushiki KaishaPolyaryl ether sulfone semipermeable membrane and process for producing sameEP0008945A2 *Sep 5, 1979Mar 19, 1980Teijin LimitedSemipermeable composite membrane, process for producing said membrane, and method of desalination using said membrane* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS4830885 *Jun 8, 1987May 16, 1989Allied-Signal Inc.Chlorine-resistant semipermeable membranesUS4865744 *Jul 25, 1988Sep 12, 1989Ciba-Geigy CorporationProcess for the continuous workup of aqueous crude dye suspensionsUS4889633 *Aug 3, 1988Dec 26, 1989Ciba-Geigy CorporationProcess for treating aqueous fluids containing organic compounds and salts of polyvalent inorganic acidsUS4970034 *Sep 23, 1988Nov 13, 1990W. R. Grace & Co.-Conn.Process for preparing isotropic microporous polysulfone membranesUS4970271 *Jan 18, 1989Nov 13, 1990Imperial Chemical Industries PlcAromatic polymerUS5049282 *Apr 11, 1990Sep 17, 1991Aligena AgSemipermeable composite membranesUS5151182 *Aug 30, 1991Sep 29, 1992Membrane Products Kiryat Weizmann Ltd.Polyphenylene oxide-derived membranes for separation in organic solventsUS5173191 *Oct 5, 1989Dec 22, 1992Exxon Research And Engineering CompanyInterfacially polymerized membranes for the reverse osmosis separation of organic solvent solutionsUS5182022 *Jun 19, 1991Jan 26, 1993Texaco Inc.Dewatering of concentrated aqueous solutions by pervaporationUS5182024 *Dec 5, 1990Jan 26, 1993Exxon Research And Engineering CompanySeparation of hydrocarbon dewaxing and deasphalting solvents from dewaxed and/or deasphalted oil using interfacially polymerized membraneUS5205934 *Aug 13, 1992Apr 27, 1993Membrane Products Kiryat Weitzman Ltd.Silicone-derived solvent stable membranesUS5265734 *Dec 8, 1992Nov 30, 1993Membrane Products Kiryat Weitzman Ltd.Silicon-derived solvent stable membranesUS5279739 *Aug 19, 1991Jan 18, 1994Koch Membrane Systems, Inc.Durable filtration membrane having optimized molecular weightUS5547575 *Dec 23, 1994Aug 20, 1996Sartorius AgMethod for the surface modification of formed bodies and formed bodies produced therebyUS6077376 *Oct 22, 1997Jun 20, 2000Membrane Products Kiryat Weizman Ltd.Process for producing a tubular membrane assemblyUS6086764 *Jun 10, 1998Jul 11, 2000Crosswinds, Inc.Semipermeable encapsulated membranes with improved acid and base stability process for their manufacture and their useUS6149822 *Mar 1, 1999Nov 21, 2000Polymer Ventures, Inc.Bio-film controlUS6395189Nov 21, 2000May 28, 2002Polymer Ventures, Inc.Method for the control of biofilmsUS6596167 *Mar 26, 2001Jul 22, 2003Koch Membrane Systems, Inc.Hydrophilic hollow fiber ultrafiltration membranes that include a hydrophobic polymer and a method of making these membranesUS6780327Feb 25, 2000Aug 24, 2004Pall CorporationPositively charged membraneUS6851561Jul 15, 2004Feb 8, 2005Pall CorporationPositively charged membraneUS6890435 *Jan 28, 2002May 10, 2005Koch Membrane SystemsHollow fiber microfiltration membranes and a method of making these membranesUS7070721Oct 21, 2004Jul 4, 2006Koch Membrane SystemsMethod of making and using a hollow fiber microfiltration membraneUS7081273 *Aug 29, 2005Jul 25, 2006Jiang JiMethod for producing defect free composite membranesUS7094347Jan 18, 2005Aug 22, 2006Pall CorporationPositively charged membraneUS7165682 *Jul 16, 2003Jan 23, 2007Accord Partner LimitedDefect free composite membranes, method for producing said membranes and use of the sameUS7172075 *Aug 8, 2003Feb 6, 2007Accord Partner LimitedDefect free composite membranes, method for producing said membranes and use of the sameUS7223341Jul 6, 2006May 29, 2007Pall CorporationPositively charged membraneUS7291696Nov 4, 2005Nov 6, 2007General Electric CompanyComposition and associated methodUS7381331Sep 30, 2005Jun 3, 2008General Electric CompanyHydrophilic membrane and associated methodUS7396465May 1, 2007Jul 8, 2008Pall CorporationPositively charged membraneUS7631768Nov 4, 2005Dec 15, 2009General Electric CompanyMembrane and associated methodUS7669720 *Dec 15, 2006Mar 2, 2010General Electric CompanyFunctional polyarylethersUS7681741 *Dec 15, 2006Mar 23, 2010General Electric CompanyFunctional polyarylethersUS7695628Dec 15, 2006Apr 13, 2010General Electric CompanyPolyarylether membranesUS7888397Apr 30, 2008Feb 15, 2011Sandia CorporationPoly(phenylene)-based anion exchange membraneUS7910012Jul 16, 2007Mar 22, 2011General Electric CompanyComposition, membrane, and associated methodUS7977451Dec 15, 2006Jul 12, 2011General Electric CompanyPolyarylether membranesUS8026339Jun 1, 2007Sep 27, 2011Samsung Sdi Co., Ltd.Polysulfone, electrolyte membrane using the same, and fuel cell using the electrolyte membraneUS8123945May 9, 2007Feb 28, 2012The United States of America as represented by the Secretary of the Interior, The Bereau of ReclamationMethod for making high flux, high salt rejection cellulose desalting membranesEP0352798A2 *Jul 27, 1989Jan 31, 1990Asahi Glass Company Ltd.Anion exchangerWO2009098161A1 *Jan 29, 2009Aug 13, 2009Polymers Crc LtdAlkoxyamine functionalized polysulfone-comb-copolymersWO2010086630A1Feb 2, 2010Aug 5, 2010Ntnu Technology Transfer AsGas separation membrane* Cited by examinerClassifications U.S. Classification210/654, 210/500.42, 210/500.28, 210/500.29, 210/500.37, 210/500.33, 210/500.41, 210/500.38, 210/500.39International ClassificationC08J9/28, B01D61/14, C08J5/18, B01D71/82, C08J9/36, C08G75/00, B01D71/68, C08G75/20, C08G65/48, B01D61/02, C08J5/22Cooperative ClassificationC08J2379/06, C08G75/20, C08G65/48, B01D61/025, C08J5/2256, B01D71/68, B01D69/10, B01D67/0093European ClassificationC08G75/20, C08G65/48, C08J5/22B2D, B01D71/68, B01D67/00R18, B01D69/10, B01D61/02DLegal EventsDateCodeEventDescriptionNov 9, 1999FPExpired due to failure to pay maintenance feeEffective date: 19990901Aug 29, 1999LAPSLapse for failure to pay maintenance feesMar 23, 1999REMIMaintenance fee reminder mailedFeb 27, 1995FPAYFee paymentYear of fee payment: 8Mar 1, 1991FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google