Caustic resistant membrane

Patent metadata

Field	Value
Publication number	US-9327247-B2
Application number	US-51562807-A
Country	US
Kind code	B2
Filing date	Oct 29, 2007
Priority date	Nov 21, 2006
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

The invention relates to caustic resistant membranes formed by solvent casting a blend of one or more polyvinylidene fluoride polymers with one or more acrylic polymers.

First claim

What is claimed is:

1. A caustic-resistant membrane comprising a homogeneous polymer blend consisting of:
a) 75 to 90 percent by weight of at least one polyvinylidene fluoride (PVDF) polymer or copolymer; and
b) 10 to 25 percent by weight of at least one acrylic polymer, wherein said acrylic polymer is selected from the group consisting of
1) a terpolymer consisting of from 90 to 99 weight percent of methyl methacrylate monomer units, from 0.5 to 9.5 weight percent of one or more C 1-4 alkyl acrylates monomer units and 0.5 to 5 weight percent of (meth)acrylic acid monomer units, wherein the total of these acrylic monomers adds to 100%, and
2) an acrylic block copolymer consisting of all acrylic monomers units wherein at least one end block consists of 75-100 percent by weight of methyl methacrylate units, and from 0 to 25 weight percent of one or more C 1-4 alkyl acrylates and/or (meth)acrylic acid,

wherein said membrane is microporous, having a pore size of from 0.01 to 10 microns.

2. The membrane of claim 1 wherein said PVDF polymer comprises a copolymer of 85-95 mole percent of polyvinylidene fluoride and 5 to 15 mole percent of hexafluoropropylene.

3. The membrane of claim 1 wherein said PVDF polymer has a molecular weight of from 100,000 to 5,000,000 g/mol.

4. The membrane of claim 1 wherein said acrylic polymer has a molecular weight of from 30,000 to 500,000 g/mol.

5. The membrane of claim 1 , wherein said acrylic block copolymer is a triblock copolymer having a polybutyl acrylate center block and methylmethacrylate or methylmethacrylate copolymers as end blocks.

6. The membrane of claim 1 , wherein the PVDF and acrylic polymer resins are pre-blended, in the appropriate ratio, by melt extrusion into a pelletized form and then subsequently used in the membrane preparation.

7. The membrane according to claim 1 , wherein the PVDF and acrylic polymer resins are pre-blended, in the appropriate ratio, by melt extrusion into a pelletized form and then ground into a powder form, which is subsequently used in the membrane preparation.

8. The membrane according to claim 1 , wherein the PVDF and acrylic polymer resins are pre-blended as separate powders to give a powder blend of uniform consistency in the appropriate ratio for use in the membrane formulation.

9. The membrane of claim 1 , wherein said membrane is a hollow fiber membrane, a supported hollow fiber membrane, a flat unsupported membrane, or a flat supported membrane.

10. The membrane of claim 1 comprising an article for water purification, purification of biological fluids, wastewater treatment, osmotic distillation, and process fluid filtration.

11. The membrane of claim 1 , wherein said terpolymer consists of from 90 to 99 weight percent of methyl methacrylate monomer units, from 0.5 to 9.5 weight percent of ethyl acrylate monomer units and 0.5 to 5 weight percent of (meth)acrylic acid monomer units, wherein the total of these acrylic monomers adds to 100%.

12. The membrane of claim 11 , wherein said terpolymer consists of 95.5-98.5 weight percent of methyl methacrylate monomer units, from 1 to 4 weight percent of ethyl acrylate monomer units and 0.5 to 3.5 weight percent of (meth)acrylic acid monomer units, wherein the total of these acrylic monomers adds to 100%.

Assignees

• Kosar Walter
• Arkema Inc

Inventors

• Kosar Walter

Classifications

• B01D71/80

  Block polymers · CPC title

• B01D69/02

  characterised by their properties · CPC title

• B01D71/34 Primary

  Polyvinylidene fluoride · CPC title

• C02F1/44

  by dialysis, osmosis or reverse osmosis {(general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268)} · CPC title

• C08J2433/12

  Homopolymers or copolymers of methyl methacrylate · CPC title