# US 10,118,133 B2 · Ultrafiltration membranes and methods of making

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- Number: US 10,118,133 B2
- Document ID: US10118133B2
- Status: Granted
- Kind: B2
- Application number: 15/421,103
- Filed: 2017-01-31
- Published: 2017-05-18
- Granted: 2018-11-06
- Earliest claimed: 2004-06-25
- Assignees: EMD Millipore Corporation
- Applicants: EMD Millipore Corporation
- Inventors: Gabriel Tkacik; Willem Kools; Nitin Satav; Philip Goddard
- Web page: https://patentgrep.com/patent/US10118133B2

## CPC

- B01D 69/1213: {Laminated layers}
- B01D 61/145: {Ultrafiltration}
- B01D 67/0013: {Casting processes}
- B01D 67/00165: {Composition of the coagulation baths}
- B01D 67/0018: {Thermally induced processes [TIPS]}
- B01D 71/34: Polyvinylidene fluoride
- B01D 71/68: Polysulfones; Polyethersulfones
- C07K 1/34: by filtration, ultrafiltration or reverse osmosis
- B01D 2323/12: Specific ratios of components used
- B01D 2323/42: Details of membrane preparation apparatus
- B01D 2325/022: Asymmetric membranes
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C07K: PEPTIDES (peptides in foodstuffs A23; obtaining protein compositions for foodstuffs, working-up proteins for foodstuffs A23J; preparations for medicinal purposes A61K; peptides containing beta-lactam rings C07D; cyclic dipeptides not having in their molecule any other peptide link than those which form their ring, e.g. piperazine-2,5-diones, C07D; ergot alkaloids of the cyclic peptide type C07D519/02; macromolecular compounds having statistically distributed amino acid units in their molecules, i.e. when the preparation does not provide for a specific; but for a random sequence of the amino acid units, homopolyamides and block copolyamides derived from amino acids C08G69/00; macromolecular products derived from proteins C08H1/00; preparation of glue or gelatine C09H; single cell proteins, enzymes C12N; genetic engineering processes for obtaining peptides C12N15/00; compositions for measuring or testing processes involving enzymes C12Q; investigation or analysis of biological material G01N33/00)

## Abstract

The present invention is an integral multilayered composite membrane having at least one ultrafiltration layer made by cocasting or sequentially casting a plurality of polymer solutions onto a support to form a multilayered liquid sheet and immersing the sheet into a liquid coagulation bath to effect phase separation and form a multilayered composite membrane having at least one ultrafiltration layer.

## Claims

### Claim 1

A virus removal methodology comprising:
providing a filtration device comprising a housing having a fluid inlet and a filtrate outlet, and containing at least one two-layered membrane having one asymmetric ultrafiltration layer in which particles having a 20 to 100 nanometer (nm) diameter are retained and one microporous asymmetric layer in which particles larger than 0.1 μm are retained, wherein the membrane is produced from two polymer solutions and the membrane has an integral transition zone between the ultrafiltration layer and the microporous layer, wherein the transition zone is a region where the pore size transitions from the ultrafiltration layer to the microporous layer, wherein:
the layers of the membrane are each substantially hydrophilic,
at least one of the layers of the membrane is capable of substantially preventing the passage therethrough of a virus and both layers are capable of substantially permitting the passage therethrough of a protein,
the layers of the membrane each having a tight-side and an open-side, the average surface pore size of said tight-side being less than the average surface pore size of said open-side to form the asymmetric layers, and
a first layer of the membrane being oriented such that fluid introduced into said housing through the fluid inlet commences passage through said first layer through the open-side;
providing a manufactured protein-containing solution comprising a predominant solute, wherein the predominant solute in the solution is said protein, and wherein the solution is prone to contamination by said virus; and
flowing the solution through the filtration device under conditions sufficient to effect substantial passage of the protein through each layer of the membrane and out of the housing through the filtrate outlet, whereby any virus contaminating the manufactured protein-containing solution is substantially prevented from passage through the membrane, and is substantially removed from the solution.

### Claim 2 (depends on 1)

The virus removal methodology of claim 1, wherein each of the layers of the membrane has a porosity defined to enable performance of the virus removal methodology, yielding a log reduction value (LRV) for removal of a virus from the solution greater than 6 and a protein passage greater than 98%.

### Claim 3 (depends on 1)

The virus removal methodology of claim 1, wherein the ultrafiltration layer is on top of the microporous layer.

### Claim 4 (depends on 1)

The virus removal methodology of claim 1, wherein the ultrafiltration layer is on top of the microporous layer and the polymer solution forming the ultrafiltration layer has a critical solution temperature such that the ultrafiltration layer is formed by a temperature induced phase separation and the microporous layer is formed by phase separation in a coagulation bath.

### Claim 5 (depends on 1)

The virus removal methodology of claim 1, wherein the ultrafiltration layer is on top of the microporous layer and the polymer solution forming the ultrafiltration layer has a critical solution temperature such that the ultrafiltration layer is formed by a temperature induced phase separation and the polymer solution forming the microporous layer is made of a material selected from the group consisting of a material having a critical solution temperature higher than that of the ultrafiltration layer and a material having no critical solution temperature.

### Claim 6 (depends on 1)

The virus removal methodology of claim 1, wherein the ultrafiltration layer is on top of the microporous layer and the polymer solution forming the microporous layer has a critical solution temperature such that the microporous layer is formed by a temperature induced phase separation and the ultrafiltration layer is formed by phase separation in a coagulation bath.

### Claim 7 (depends on 1)

The virus removal methodology of claim 1, wherein the ultrafiltration layer is on top of the microporous layer and the polymer solution forming the microporous layer has a critical solution temperature such that the microporous layer is formed by a temperature induced phase separation and the ultrafiltration layer is made of a material selected from the group consisting of a material having a critical solution temperature higher than that of the microporous layer and a material having no critical solution temperature.

### Claim 8 (depends on 1)

The virus removal methodology of claim 1, wherein the two polymer solutions comprise polymers independently selected from the group consisting of polyvinylidene fluoride, nylons, polyamides, polyimides, polyetherimides, polyethersulfones, polysulfones, polyarylsulfones, cellulose, regenerated cellulose, cellulose esters, polystyrenes, acrylic polymers methacrylic polymers, copolymers acrylic methacrylic polymers, and combinations thereof.

### Claim 9 (depends on 8)

The virus removal methodology of claim 8, wherein each asymmetric layer is composed of polyethersulfone.

### Claim 10 (depends on 1)

The virus removal methodology of claim 1, wherein the ultrafiltration layer comprises a skinned, asymmetric ultrafiltration membrane layer.

### Claim 11 (depends on 1)

The virus removal methodology of claim 1, wherein the ultrafiltration layer is 2 to 100 microns thick and the microporous layer is 50-200 microns thick.

### Claim 12 (depends on 11)

The virus removal methodology of claim 11, wherein the ultrafiltration layer is 2 to 50 microns thick.

### Claim 13 (depends on 11)

The virus removal methodology of claim 11, wherein the microporous layer is 80 to 150 microns thick.

### Claim 14 (depends on 11)

The virus removal methodology of claim 11, wherein the membrane is 90 to 120 microns thick.

### Claim 15 (depends on 11)

The virus removal methodology of claim 11, wherein the microporous layer has a polymer content of 10% to 20% by weight polymer solids.

### Claim 16 (depends on 1)

The virus removal methodology of claim 1, wherein the ultrafiltration layer has a polymer content of 15% to 30% by weight polymer solids.

### Claim 17 (depends on 1)

The virus removal methodology of claim 1, wherein the ultrafiltration membrane layer has pores sized to retain a parvo virus.