Electrostatic solution spinning for producing very fine fiber non-wovens involves changes in solvent concentration during spinning to induce phase separation

摘要

In a electrostatic solution spinning process according to for producing non-wovens containing fibers below 1 mu m diameter, phase separation is induced by altering the concentration ratio of the components. The solvent evaporates as the fibers are formed. Treatments include addition of disinfecting biocides, fungicides, incorporation of fillers or irradiation. Continuous structures with an interpenetrating network are produced. An independent claim is included for a non-woven (1) produced in this way, particularly for one with repeating sets of layers with varying fiber diameters and pore concentration (3) in the layers (2), e.g. the fiber diameter increases from top to bottom in the direction of the lower layer (4) from less than 1 mu m to 1 to 30 mu m. The lower layer (4) can be a stabilizing non-woven. The fibers can carry an electrostatic charge and part of the material can be hydrophilic and part hydrophobic.