The most commonly used breathable film with PE as the carrier

The principle of air permeability: inorganic material + tensile = micropores, but only the appropriate size and uniform distribution of micropores are effective.

Basic film forming principle: PE+CaCO₃ (masterbatch) -- film forming -- stretch -- breathable film

PE breathable film is in LDPE/LLDPE polyethylene resin carrier, adding about 50% of special calcium carbonate for mixing, it's made by directional stretching at a certain rate after extrusion into a film. Since polyethylene resin is a thermoplastic plastic material, it can be stretched and crystallized under certain conditions. When stretched, the interface between the polymer and the calcium carbonate particles is stripped, and the interconnected pores or channels are formed around the calcium carbonate particles. It is these pores and channels that give the film a breathable (wet) function.