When the silicone milk is heated above 140 °C, the polysiloxane is oriented on the fabric, the hydrophobic group CH3 faces outward, and the silicon atom, oxygen atom and some of the fiber on the silicone oil emulsion The atoms form a coordinate bond and a hydrogen bond, so that water vapor and air can pass through the fabric, but the water droplets are not transparent. The hydroxyl group at the top of the polysiloxane oil emulsion chain is grafted with hydrogen-containing silicone oil, that is, the Si.H bond in the hydrogen-containing silicone oil is hydrolyzed to Si.H, which is dehydrated and grafted with the terminal hydroxyl group of the silicone oil to form a long-chain molecule, and the molecule becomes larger and softer. Can increase water repellency. The silicone oil and the hydrogen-containing silicone oil are crosslinked at 150-180 ° C on the surface of the fabric to form a water- and solvent-insoluble polyorganosiloxane resin film. In the silane structure, the methyl group faces outward, causing water repellency, film discontinuity and gas permeability.