Waterproof breathable membrane (breathing paper) is a new type of polymer waterproof material. From the production process, the technical requirements of waterproof breathable membranes are much higher than those of general waterproof materials; at the same time, from the perspective of quality, waterproof breathable membranes also have functional features that other waterproof materials do not possess.
The waterproof breathable membrane works:
In the state of water vapor, the water particles are very small, and according to the principle of capillary motion, the capillary can be penetrated to the other side smoothly, so that the phenomenon of vapor transmission occurs. When water vapour condenses into water droplets, the particles become larger. Due to the surface tension of the water droplets (water molecules “pull and pull each other”), the water molecules cannot smoothly separate from the water droplets and penetrate the other side. Water infiltration occurs and the vapor-permeable membrane has a waterproof function.
Waterproof breathable film material:
The technology of waterproof and breathable membranes was first introduced from Europe and the United States. However, the production technology of domestic products was varied, and the quality of products from various manufacturers was uneven, failing to form a unified quality standard. In fact, waterproof breathable membranes are mainly composed of three layers: PP spunbond nonwovens, PE polymer breathable membranes, PP spunbond nonwovens. The role of spunbonded non-woven fabrics is mainly to enhance tensile and hydrostatic pressure and protect the middle layer (breathable film). The real breathability is mainly based on the middle layer PE polymer breathable film.