Semipermeable composite membrane
First Claim
1. A semipermeable composite membrane comprising a thin semipermeable film of a polymeric material deposited on one side of a microporous substrate, said polymeric material being prepared by crosslinking a soluble polymer containing at least 30 mole% of a recurring unit of the formula ##STR77## wherein Y represents a direct bond, a methylene group, a carbonyl group of the formula ##STR78## or an unsubstituted or substituted phenylene group;
- R1 represents a hydrogen atom, or a mono-valent organic radical containing 1 to 20 carbon atoms which may contain an amino group containing 1 to 2 active hydrogen atoms and a heteroatom selected from the group consisting of oxygen, nitrogen and sulfur atoms;
R2 represents a hydrogen atom, an amino group containing 1 to 2 active hydrogen atoms or a monovalent oganic radical containing 1 to 20 carbon atoms and which contains at least one amino group containing 1 to 2 active hydrogen atoms and which may contain a heteroatom selected from the group consisting of oxygen, nitrogen and sulfur atoms;
R1 and R2, together with the nitrogen atom to which they are bonded may represent a 5- to 18-membered nitrogen-containing heterocyclic ring which contains at least one amino group having one active hydrogen atom;
R3 represents an alkylene group containing 2 to 5 carbon atoms which may have an --OH group;
R4 represents a hydrogen atom or a methyl group,and having at least 0.5 milliequivalent, per gram of said polymer, of an amino group containing 1 or 2 active hydrogen atoms, with a polyfunctional compound containing at least two functional groups capable of reacting with the amino group having 1 or 2 active hydrogen atoms.
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Abstract
A semipermeable composite membrane comprising a thin semipermeable film of a polymeric material deposited on one side of a microporous substrate, the polymeric material being prepared by crosslinking a soluble polymer containing at least 30 mole % of a recurring unit of the formula ##STR1## wherein all symbols are as defined herein, and having at least 0.5 milliequivalent, per gram of said polymer, of an amino group containing 1 or 2 active hydrogen atoms, with a polyfunctional compound containing at least two functional groups capable of reacting with the amino group having 1 or 2 active hydrogen atoms; and a process for preparing the same. The semipermeable composite membrane of this invention is especially useful for desalination of saline or brackish water by reverse osmosis.
122 Citations
31 Claims
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1. A semipermeable composite membrane comprising a thin semipermeable film of a polymeric material deposited on one side of a microporous substrate, said polymeric material being prepared by crosslinking a soluble polymer containing at least 30 mole% of a recurring unit of the formula ##STR77## wherein Y represents a direct bond, a methylene group, a carbonyl group of the formula ##STR78## or an unsubstituted or substituted phenylene group;
- R1 represents a hydrogen atom, or a mono-valent organic radical containing 1 to 20 carbon atoms which may contain an amino group containing 1 to 2 active hydrogen atoms and a heteroatom selected from the group consisting of oxygen, nitrogen and sulfur atoms;
R2 represents a hydrogen atom, an amino group containing 1 to 2 active hydrogen atoms or a monovalent oganic radical containing 1 to 20 carbon atoms and which contains at least one amino group containing 1 to 2 active hydrogen atoms and which may contain a heteroatom selected from the group consisting of oxygen, nitrogen and sulfur atoms; R1 and R2, together with the nitrogen atom to which they are bonded may represent a 5- to 18-membered nitrogen-containing heterocyclic ring which contains at least one amino group having one active hydrogen atom; R3 represents an alkylene group containing 2 to 5 carbon atoms which may have an --OH group; R4 represents a hydrogen atom or a methyl group, and having at least 0.5 milliequivalent, per gram of said polymer, of an amino group containing 1 or 2 active hydrogen atoms, with a polyfunctional compound containing at least two functional groups capable of reacting with the amino group having 1 or 2 active hydrogen atoms. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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8. The membrane of claim 1 wherein said polymer is a polymer consisting essentially of the recurring unit of formula (I).
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9. The membrane of claim 1 wherein said polymer is a copolymer composed of a recurring unit of formula (I-a) ##STR81## where R1 and R2 are as defined in claim 1, and at least one other recurring unit derived from a radical polymerizable monomer containing one ethylenically unsaturated bond.
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10. The membrane of claim 9 wherein said monomer containing one ethylenically unsaturated bond contains 2 to 10 carbon atoms.
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11. The membrane of claim 9 wherein said monomer containing one ethylenically unsaturated bond has a molecular weight of 28 to 200.
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12. The membrane of claim 9 wherein said monomer is a compound represented by the following formula (III-1) ##STR82## wherein R6 represents a hydrogen atom or an alkoxycarbonyl group with the alkyl moiety containing 1 to 10 carbon atoms;
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R7 represents a hydrogen or halogen atom or a methyl group; R8 represents a hydrogen or halogen atom, an alkoxy group containing 1 to 10 carbon atoms optionally substituted by a hydroxyl group and/or a halogen atom, an alkoxycarbonyl group with the alkyl moiety containing 1 to 10 carbon atoms, an alkanoyl group containing 1 to 10 carbon atoms, an alkanoyloxy group containing 1 to 10 carbon atoms, an alkyl group consisting 1 to 10 carbon atoms substituted by a group of the formula --SO3 M or hydroxyl group, a phenyl group optionally substituted by the group --SO3 M or a methyl group, a glycidyloxy group, or a group of the formula --B--O)j H in which B represents an ethylene or propylene group, and j is an integer of 1 to 8; and
M represents an alkali atom.
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13. The membrane of claim 1 wherein said polymer is a copolymer composed of
(A) at least 50 mole% of the recurring unit of formula (I-a) ##STR83## where R1 and R2 are as defined in claim 1, and (B) up to 50 mole% of at least one recurring unit of the formula ##STR84## wherein R13 represents a hydrogen atom or an alkoxycarbonyl group with the alkyl moiety containing 1 to 10 carbon atoms; -
R14 represents a hydrogen or halogen atom or a methyl group; R15 represents a hydrogen or halogen atom, an alkoxy group containing 1 to 10 carbon atoms optionally mono- or di-substituted by a hydroxyl group and/or a halogen atom, an alkoxycarbonyl group with the alkyl moiety containing 1 to 10 carbon atoms, an alkanoyl group containing 1 to 10 carbon atoms, an alkanoyloxy group containing 1 to 10 carbon atoms, an alkyl group containing 1 to 10 carbon atoms which may be mono-substituted by a group of the formula --SO3 M or a hydroxy group, a phenyl group optionally mono-substituted by the group --SO3 M or a methyl group, a glycidyloxy group, a group of the formula (B--O)j H in which B represents an ethylene or propylene group and j is an integer of 1 to 8, a group of the formula ##STR85## a group of the formula ##STR86## a group of the formula ##STR87## in which R1 and R2 are defined hereinabove;
R13 and R14 together may represent an ethylenedioxy group;R14 and R15 together may represent ##STR88## and M represents an alkali metal atom.
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14. The membrane of claim 1 wherein said polymer has a solubility of at least 0.1 g at 25°
- C. in 100 g of water or a water-miscible polar organic solvent.
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15. The membrane of claim 1 wherein said polymer has a solubility of at least 0.5 g at 25°
- C. in 100 g of water or a water-miscible polar organic solvent.
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16. The membrane of claim 14 or 15 wherein said organic solvent is selected from the group consisting of lower alcohols, formic acid, dimethylformamide, dimethylsulfoxide, tetramethylenesulfone and N-methylpyrrolidone.
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17. The membrane of claim 1 wherein said polymer has an inherent viscosity, determined at 30°
- C. in water or a water-miscible polar organic solvent selected from the group consisting of lower alcohols, formic acid, dimethylformamide, dimethylsulfoxide, tetramethylenesulfone and N-methylpyrrolidone at 0.5% by weight of the polymer solution, of at least 0.15 dl/g.
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18. The membrane of claim 1 wherein said polymer has an inherent viscosity, determined at 30°
- C. in water or a water-miscible polar organic solvent selected from the group consisting of lower alcohols, formic acid, dimethylformamide, dimethylsulfoxide, tetramethylenesulfone and N-methylpyrrolidone at 0.5% by weight of the polymer solution, of 0.10 to 5.0 dl/g.
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19. The membrane of claim 1 wherein said polyfunctional compound is a polyfunctional compound containing at least two functional groups selected from the group consisting of acid halide, sulfonyl halide, isocyanate, N-haloformyl, haloformate and acid anhydride groups, or cyanuric chloride.
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20. The membrane of claim 1 wherein the polyfunctional compound is an aromatic, heterocyclic or alicyclic compound.
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21. The membrane of claim 1 wherein the polyfunctional compound is an aromatic compound.
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22. The membrane of claim 1 wherein the polyfunctional compound is a di- or tri-functional aromatic compound containing two or three functional groups selected from the group consisting of acid halide, sulfonyl halide and acid anhydride groups.
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23. The membrane of claim 1 wherein the polyfunctional compound is a trifunctional aromatic compound, or a mixture of a difunctional aromatic compound and a trifunctional aromatic compound.
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24. The membrane of claim 23 wherein the di- or tri-functional aromatic compound is isophthaloyl chloride, terephthaloyl chloride, trimesoyl chloride, 3-chlorosulfonylisophthaloyl chloride, or cyanuric acid chloride.
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25. The membrane of claim 1 wherein said thin semipermeable film has a thickness of at least about 100 A.
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26. The membrane of claim 1 wherein said microporous substrate is composed of an asymmetrical membrane of an aromatic polysulfone.
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27. In a method for desalination of saline or brackish water by reverse osmosis comprising contacting the saline or brackish water under pressure with a reverse osmosis membrane, the improvement wherein the membrane of claim 1 is used as the reverse osmosis membrane.
- R1 represents a hydrogen atom, or a mono-valent organic radical containing 1 to 20 carbon atoms which may contain an amino group containing 1 to 2 active hydrogen atoms and a heteroatom selected from the group consisting of oxygen, nitrogen and sulfur atoms;
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28. A process for producing a sermipermeable composite membrane which comprises
(a) crosslinking, on a microporous substrate or on a water solution, (i) a soluble polymer containing at least 30 mole % of a recurring unit of formula (I) ##STR89## wherein Y represents a direct bond, a methylene group, a carbonyl group of the formula ##STR90## or an unsubstituted or substituted phenylene group; - R1 represents a hydrogen atom, or a monovalent organic radical containing 1 to 20 carbon atoms which may contain an amino group containing 1 to 2 active hydrogen atoms and a heteroatom selected from the group consisting of oxygen, nitrogen and sulfur atoms;
R2 represents a hydrogen atom, an amino group containing 1 to 2 active hydrogen atoms or a monovalent organic radical containing 1 to 20 carbon atoms which contains at least one amino group containing 1 to 2 active hydrogen atoms and may contain a heteroatom selected from the group consisting of oxygen, nitrogen and sulfur atoms; R1 and R2, together with the nitrogen atom to which they are bonded, may represent a 5- to 18-membered nitrogen-containing hetero-cyclic ring which contains at least one amino group having one active hydrogen atom; R3 represents an alkylene group containing 2 to 5 carbon atoms which may have an --OH group; and R4 represents a hydrogen atom or a methyl group, and having at least 0.5 milliequivalent, per gram of said polymer, of an amino group containing 1 or 2 active hydrogen atoms, with (ii) a polyfunctional compound containing at least two functional groups capable of reacting with the amino groups having one or two active hydrogen atoms, and (b) when the crosslinking reaction is carried out on a water solution, placing the thus formed membrane on a microporous substrate, and (c) optionally heating the membrane and substrate to ensure bonding thereof. - View Dependent Claims (29, 30, 31)
- R1 represents a hydrogen atom, or a monovalent organic radical containing 1 to 20 carbon atoms which may contain an amino group containing 1 to 2 active hydrogen atoms and a heteroatom selected from the group consisting of oxygen, nitrogen and sulfur atoms;
Specification