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US 2023/0390710 A1Published application
Membranes made using fine powders
AssigneeArkema Inc.
InventorsGregory S. O'BRIEN, Walter P. KOSAR, Saeid ZERAFATI
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Abstract
This invention allows for the production of high strength and high permeability TIPS membranes using extractable fillers with fine powder PVDF grades.
Claims22
A composition for TIPS membranes comprising
- 30 to 50% PVDF,
- 15 to 25% fine powder extractable filler having an average particle size of between 1 to 250 nm,
- 35 to 55% organic latent solvent, and
- 0 to 10% additives,
- wherein the PVDF has a heat of melting Delta H of from 45 to 55 l/gm on the second heat D3418 (DSC), and the percent of reverse units by NMR is from 4.6 to 5.8.
2 more elements
A method for producing a porous membrane comprising the steps of
- (a) pre-blending fine powder PVDF having a D50 of 3 to 15 micron, fine powder extractable filler having average particle sizes of between 1 to 250 nm and latent solvent to produce a free flowing powder blend, wherein the free flowing powder blend contains 15-30% by weight of a latent solvent,
- (b) feeding the free flowing powder blend to an extruder or kneader wherein the free flowing powder blend is melted to produce a melted blend,
- (c) feeding an additional aliquot of latent solvent down-stream in the extruder or kneader into the melted blend to produce a melted product,
- (d) extruding the melted product to form a structure,
- (e) extracting the solvent from the structure with organic solvent, preferably alcohol, and
- (f) extracting the filler with acid or base, to produce a porous membrane.
3 more elements
(canceled)
Dependencies are inferred from the claim text.