Composite breathing filter material with hydrophobic, dust-filtering, air-permeable and moisture-permeable functions and preparation method of composite breathing filter material

The invention belongs to the field of filter material preparation, and particularly relates to a composite breathing filter material with hydrophobic, dust-filtering, air-permeable and moisture-permeable functions and a preparation method of the composite breathing filter material. The breathing filter material is of a three-stage composite structure and is composed of an outer layer filter membrane, a middle layer filter membrane and an inner layer filter membrane, the outer layer filter membrane is a polyvinylidene fluoride fiber membrane, the middle layer filter membrane is a bionic fiber membrane prepared by adding lauryl sodium sulfate into polyvinylidene fluoride, and the inner layer filter membrane is a bionic fiber membrane prepared by adding lauryl sodium sulfate into polyvinylidene fluoride. And the inner-layer filter membrane is a fiber membrane prepared from chitosan and polyvinyl alcohol. Aiming at the composite breathing filter material with high temperature and high humidity of a mine and high