Polypropylene waterproof breathable film and production process thereof

The invention discloses a polypropylene waterproof breathable film and a production process thereof. The polypropylene waterproof breathable film comprises the following raw materials in parts by weight: 70-90 parts of polypropylene, 15-25 parts of modified nano silicon dioxide, 1-3 parts of a regulator, 1-2 parts of a plasticizer and 1-2 parts of an antioxidant. The preparation method comprises the following steps: blending the raw materials, adding the blended raw materials into a double-screw extruder, extruding a melt, filtering the melt, extruding the melt into a membrane through a single-layer die head, quenching the membrane to form a cast sheet, and longitudinally stretching the cast sheet for 4-5 times to obtain a primary membrane; transversely stretching the prepared primary film by 4-5 times, cooling, shaping, flattening and rolling to prepare the polypropylene waterproof and breathable film; polypropylene is used as a matrix and does not contain hydrophilic (polar) groups, so that the polypropylen