Preparation method for high-moisture- permeability fluorine-containing super- oleophobic microporous membrane

A preparation method of a high-moisture-permeability fluorine-containing super-oleophobic microporous membrane, the preparation method comprises the following steps:

• (1) preparing a white opaque mixture of fluorine-containing polymers:
• adding the materials in sequence according to a weight ratio of A:B:C:D of 65%-80%:6%-15%:2%-23%:0-2%, stirring and mixing uniformly in a non-shear manner, and subjecting the white opaque mixture of fluorine-containing polymers to a vacuum drying at 50° C. for at least 12 hours;
• wherein:
• A is a blend of a high molecular weight polytetrafluoroethylene dispersion resin and a fluorine-containing ion exchange resin, wherein the fluorine-containing ion exchange resin comprises one or more fluorine-containing monomers selected from tetrafluoroethylene, vinylidene fluoride, trifluoroethylene, trifluorochloroethylene, and fluoroethylene, and further comprises at least one ion-exchange functional group selected from sulfonic acid, carboxylic acid, phosphoric acid, tertiary amine, or quaternary amine;
• wherein a dry weight ratio of fluorine-containing ion exchange resin to the high molecular weight polytetrafluoroethylene dispersion resin is 0.5%-10%;
• B is a fluorine-containing alkyl acrylate monomer, or a fluorine-containing alkyl methacrylate monomer, or a mixture of monomers thereof;
• its molecular weight is less than 3000, and its melting point is below 80° C.;
• C is a polyurethane acrylate prepolymer, or a fluorine-free alkyl acrylate monomer, or a mixture thereof;
• its molecular weight is less than 8000, and its melting point is below 80° C.;
• D is a high temperature free radical initiator;
• (2) pouring the white opaque mixture of fluorine-containing polymers directly into a blank pressing column barrel, and press the blank at 20° C. to 100° C. after air-exhausting to make a cylindrical pasty mixture blank column;
• (3) extruding the pasty mixture blank column through a pusher at 20° C.-100° forming a pasty extrudate, and then calendering the pasty extrudate into strips with a thickness of 50-2000 microns;
• (4) stretching the strips unidirectionally or biaxially at 100° C. to 200° C., and finally thermally shaping at 200° C. to 390° C. to make the high-moisture-permeability fluorine-containing super-oleophobic microporous membrane.