Membrane with increased surface area

Patent metadata

Field	Value
Publication number	US-10864484-B2
Application number	US-201515325770-A
Country	US
Kind code	B2
Filing date	Jul 15, 2015
Priority date	Jul 18, 2014
Publication date	Dec 15, 2020
Grant date	Dec 15, 2020

Abstract

The present invention relates to a micro-porous filtration membrane with performance enhancing projections as well as a method for producing the same.

First claim

The invention claimed is:

1. A micro-porous filtration membrane comprising a plurality of three-dimensional projections extending from a second main surface of the membrane and originating from the micro-porous filtration membrane itself in a flat disc shape characterized in that the micro-porous structure of the material constituting the filtration membrane is substantially not compressed and in that the three-dimensional projections are formed by stamping from a first main surface of the membrane opposite to the second main surface of the membrane upon which corresponding recesses are formed on the first main surface, wherein the three-dimensional projection on the second main surface of the membrane is the negative stamping shape of the positive stamping shape of the three-dimensional projection stamped from the first main surface of the membrane, wherein the microporous filtration membrane is a multi-layer membrane comprising at least two different membrane layers having different pore sizes such that a first membrane layer on the non-filtrate side has a larger pore size compared to a second membrane layer on the filtrate side, wherein at least one of the first or second membrane layers comprises a plurality of said three dimensional projections, and wherein said at least one of the first or second membrane layers comprising the plurality of said three dimensional projections is made from polyether sulfone or polyvinylidene difluoride or a cellulose derivate or a combination thereof.

2. The micro-porous filtration membrane according to claim 1 , wherein the at least one membrane layer comprising a plurality of said three-dimensional projections is disposed on at least a second membrane layer so that the projections are in contact with the second membrane layer.

3. The micro-porous filtration membrane according to claim 1 , wherein the plurality of three-dimensional projections form a regular pattern.

4. The micro-porous filtration membrane according to claim 1 , wherein the three-dimensional projections have a cylindrical, cone, or pyramidal shape or any combination thereof.

5. The micro-porous filtration membrane according to claim 1 , wherein the percentage of the area of recess on the first main surface of the membrane is from 15 to 50%.

6. A micro-porous, multi-layer filtration membrane comprising:
at least one first porous membrane layer comprising first main surface and a second main surface, a plurality of three-dimensional projections extending from the second main surface of the at least one first porous membrane layer, and a plurality of corresponding recesses present on the first main surface of the at least one first porous member layer, wherein the three-dimensional projections and corresponding recesses of the at least one first porous membrane layer are formed by stamping the first main surface opposite to the second main surface of the at least one first porous membrane layer; and
at least one second porous membrane layer disposed on the first main surface or on the second main surface of the at least one first porous membrane layer,
wherein the at least one first porous membrane layer and the at least one second porous membrane layer have different pore sizes such that the at least one first porous membrane layer or the at least one second porous membrane layer on a non-filtrate side of the filtration membrane has a larger pore size compared to the other membrane layer on a filtrate side of the filtration membrane, wherein the filtration membrane has a micro-porous structure that is substantially not compressed, and wherein said at least one of the first or second membrane layers comprising the plurality of said three dimensional projections is made from polyether sulfone or polyvinylidene difluoride or a cellulose derivate or a combination thereof.

7. The micro-porous, multi-layer filtration membrane according to claim 6 , wherein the at least one second porous membrane layer is disposed on the second main surface of the at least one first porous membrane layer such that the plurality of three-dimensional projections on the second main surface is in contact with the at least one second membrane layer.

8. The micro-porous, multi-layer filtration membrane according to claim 7 , wherein the at least one first porous membrane layer has a larger pore size compared to the at least one second porous membrane layer.

9. The micro-porous, multi-layer filtration membrane according to claim 6 , wherein the plurality of three-dimensional projections form a regular pattern.

10. The micro-porous, multi-layer filtration membrane according to claim 6 , wherein the plurality of three-dimensional projections have a cylindrical, cone, or pyramidal shape or any combination thereof.

11. The micro-porous, multi-layer filtration membrane according to claim 6 , wherein a percentage of an area of the plurality of recesses on the first main surface of the at least one first porous membrane layer ranges from 15 to 50%.

12. The micro-porous, multi-layer filtration membrane according to claim 6 , wherein the filtration membrane is made from at least one of polyether sulfone, polyamide, a cellulose derivative, cellulose mixed ester, cellulose acetate, cellulose nitrate, cellulose, polypropylene, polyethylene, polytetrafluoroethylene, expanded polytetrafluoroethylene, polyvinylidene difluoride, or polyvinyl chloride.

13. The micro-porous, multi-layer filtration membrane according to claim 6 , wherein the at least one second porous membrane layer further comprises a first main surface and a second main surface, a plurality of three-dimensional projections extending from the second main surface of the at least one second porous membrane layer, and a plurality of corresponding recesses present on the first main surface of the at least one second porous membrane layer.

14. A method for producing a micro-porous, multi-layer filtration membrane according to claim 1 , comprising the following steps:
providing a first membrane layer and a second membrane layer, the first membrane layer having a first main surface and a second main surface;
modifying the first membrane layer so as to form a plurality of three-dimensional projections extending from the second main surface and a plurality of corresponding recesses on the first main surface of the first membrane layer,

characterized in that the step of modifying the first membrane layer is carried out by stamping from the first main surface of the first membrane layer opposite to the second main surface of the first membrane layer by using a stamping device including a positive stamp and a negative stamp, wherein a form of the positive stamp corresponds to a shape of the recesses to be formed and a form of the negative stamp corresponds to a shape of the projections to be formed; and
disposing the second membrane layer onto the first main surface or the second main surface of the first membrane layer.

15. A method for sterilizing, clarifying or purifying a liquid in sterilizing processes in food and beverage filtration of water, wine, beer or biopharmaceutical filtration of cell and bacteria nutrition media or clarification or purification filtration of cell and bacteria broths comprising filtering the liquid through the micro-porous filtration membrane of claim 1 .

Assignees

• Sartorius Stedim Biotech Gmbh

Inventors

• Mundrigi Ashok
• Gowda Jahnavi
• Mundlamuri Ramesh
• Loewe Thomas
• Linne Holger
• Handt Sebastian

Classifications

• B01D69/06

  Flat membranes · CPC title

• B01D2325/08

  Patterned membranes · CPC title

• B01D67/0086 Primary

  Mechanical after-treatment · CPC title

• B01D67/00 Primary

  Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus · CPC title