Patent ID: 6869536

Claim:
A method of manufacturing a lubricant from a perfluoropolyether-containing raw material, for said lubricant, having perfluoropolyethers of different molecular weights, comprising the steps of: providing an ultra-filtration film, made of polyethersulfone that is hydrophilic; passing pure water through said ultrafiltration film passing alcohol through said ultra-filtration film, so as to decrease the hydrophilic property of said ultra-filtration film and enable said ultra-filtration film to pass hydrophobic compounds therethrough; and after said passing alcohol, contacting said perfluoropolyether-containing raw material with said ultra-filtration film so as to divide the perfluoropolyether-containing raw material into a group of perfluoropolyethers of molecular weights that passes through the ultra-filtration film and a group of perfluoropolyethers of molecular weights that does not pass through the ultra-filtration film.