Oleophobic fluoropolymers and filter materials prepared therefrom
AssigneeEntegris, Inc.
InventorsMei Feng He, Dongzhu Wu, Yunjia Xia, Kwok-Shun Cheng
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Abstract
The disclosure provides an improved process for preparing oleophobic fluoropolymers. The resulting fluropolymers were found to be effective in imparting hydrophobic and oleophobic properties to porous polymeric membranes such as PTFE. The treated PTFE membrane can reach an oleophobic level of 6 or above, (according to the AATCC-118-1997 oil repellency test method) with a low air flux loss.
Claims12
A process for preparing a fluoropolymer, comprising the free-radical polymerization of monoethylenically-unsaturated monomers consisting of fluorine-containing monoethylenically-unsaturated monomer and fluorine-free monoethylenically-unsaturated monomer, which comprises combining:
- a. about 80 weight percent, or greater than 80 and less than 100 weight percent of the fluorine-containing monoethylenically-unsaturated monomer;
- and
- b. about 20 weight percent, or greater than 0 and less than 20 weight percent of the fluorine-free monoethylenically-unsaturated monomer;
- under free-radical polymerization conditions, in a solvent comprising at least one solvent having ester moieties, wherein the total weight percent of a. and b. is 100, and
- allowing the polymerization to proceed to a desired end point,
- wherein the fluorine-free monoethylenically-unsaturated monomer is one or more compounds of the following formulae:
- wherein each R is independently chosen from hydrogen or an alkyl group of up to 18 carbon atoms.
Dependencies are inferred from the claim text.