Poly(ethylene chlorotrifluoroethylene) membranes

• US 7,247,238 B2
• Filed: 08/09/2004
• Issued: 07/24/2007
• Est. Priority Date: 02/12/2002
• Status: Expired due to Fees

• Current Assignee: Evoqua Water Technologies LLC
• Original Assignee: Siemen Water Technologies Corporation (Siemens AG)
• Inventors: Mullette, Daniel, Muller, Heinz-Joachim
• Primary Examiner(s): FORTUNA, ANA M
• Application Number:
  US10/914,640
• Publication Number:
  US 20050098494A1
• Time in Patent Office: 1,079 Days
• Field of Search: 210/500.27, 210/500.36, 210/650, 210/500.23, 210/502.1, 210/490, 264/49, 264/127, 264/213, 264/175, 521/61, 204/296
• US Class Current: 210/500.36
• CPC Class Codes: B01D 2323/08 Specific temperatures applied
• CPC Class Codes: B01D 2323/081 Heating
• CPC Class Codes: B01D 2323/18 Pore-control agents or pore formers
• CPC Class Codes: B01D 2323/22 Specific non-solvents or non-solvent system
• CPC Class Codes: B01D 2325/022 Asymmetric membranes
• CPC Class Codes: B01D 2325/0231 Dense layers being placed on the outer side of the cross-section
• CPC Class Codes: B01D 2325/20 Specific permeability or cut-off range
• CPC Class Codes: B01D 2325/36 Hydrophilic membranes
• CPC Class Codes: B01D 2325/38 Hydrophobic membranes
• CPC Class Codes: B01D 67/0018 Thermally induced processes [TIPS]
• CPC Class Codes: B01D 67/0027 by stretching
• CPC Class Codes: B01D 67/003 by selective elimination of components, e.g. by leaching
• CPC Class Codes: B01D 67/0031 by elimination of at least one of the blocks of a block copolymer
• CPC Class Codes: B01D 67/0088 Physical treatment with compounds, e.g. swelling, coating or impregnation
• CPC Class Codes: B01D 69/08 Hollow fibre membranes manufacture of hollow fibres D01D5/24, D01F1/08
• CPC Class Codes: B01D 71/32 containing fluorine atoms
• CPC Class Codes: B29C 67/202 comprising elimination of a solid or a liquid ingredient
• CPC Class Codes: D01D 5/24 with a hollow structure; Spinnerette packs therefor D01D5/38 takes precedence; producing tubes of plastic material B29D; addition of agents forming hollow filaments D01F1/08
• CPC Class Codes: Y10T 428/249958 Void-containing component is synthetic resin or natural rubbers

Abstract

Porous polymeric membranes including Halar (poly (ethylene chlorotrifluoroethylene)) and related compounds and the methods of production thereof which avoid the use of toxic solvents. Preferred solvents, coating agents and pore forming agents are citric acid ethyl ester or glycerol triacetate. The membranes may be in the form of a hollow fiber or flat sheet, and may include other agents to modify the properties of the membrane, such as the hydrophilic/hydrophobic balance. Leachable agents may also be incorporated into the membranes.

Claims

1. A porous polymeric membrane, the membrane comprising poly(ethylene chlorotrifluoroethylene) and silica, wherein the porous polymeric membrane further comprises a coating comprising a coating agent comprising at least one compound according to formula I or formula II:

2. The porous polymeric membrane according to claim 1, wherein R₁, R₂, and R₃ are independently selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, and hexyl;

R₄ is selected from the group consisting of H, OH, COR₅, OCOR₅, methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentoxy, and hexoxy; and

R₅ is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, and hexyl.

3. The porous polymeric membrane according to claim 1, formed as a microfiltration membrane or an ultrafiltration membrane.

4. The porous polymeric membrane according to claim 1, wherein R₁, R₂, and R₃ are each ethyl, and wherein R₄ is H.

5. The porous polymeric membrane according to claim 1, wherein the compound of formula I or formula II is an environmentally friendly pore controlling agent.

6. The porous polymeric membrane according to claim 1, wherein the compound of formula I is citric acid ethyl ester.

7. The porous polymeric membrane according to claim 1, wherein the compound of formula II is glycerol triacetate.

8. The porous polymeric membrane according to claim 1, having a permeability of greater than 138 Lm⁻

2 h<sup>−

1</sup> at an applied pressure of about 100 Kpa.

9. The porous polymeric membrane according to claim 1, having a good macroscopic integrity.

10. The porous polymeric membrane according to claim 1, having uniform wall thickness.

11. The porous polymeric membrane according to claim 1, having a break force of greater than 0.86 N.