In fact, breathable membrane is not unfamiliar to us. PE film generally refers to the PE functional material with environmental protection, waterproof and breathable. It is mainly used for the bottom film of women’s sanitary napkins, the bottom film of panty liners, the bottom film of baby diapers, etc., and it is composited with non-woven fabrics. , It is also widely used in medical protective clothing, isolation clothing, medical mattresses, disposable beds, home textiles, etc. Whether the breathable base film is breathable or not, in addition to its own material function, the process is also very important.
The principle of the breathable membrane is simply: inorganic matter + stretching = micropores. Although it seems simple, the actual operation is also very particular. It is only effective when the size is appropriate and the micropores are evenly distributed. If it is understretched and the pore size is too small or even no pore size, or poorly stretched and undersized micropores, it can only become a waste product.
When the water vapor concentration on one side of the membrane is greater than the environment on the other side of the membrane, a humidity gradient pressure difference is formed. This provides the basic conditions for gas (steam) body convection. Due to the formation of convection, the humidity environment on both sides of the film tends to be relatively balanced. This is the basic principle of the breathable film.
The air permeability of the breathable bottom film mainly depends on the number of air holes and the manufacturing process of the breathable bottom film, but it is difficult to see whether it is good or bad by naked eyes when purchasing, so we all pay attention to the smell. When it comes to smell, it is not difficult to think of colloids, such as hot melt adhesives commonly used in Ji’s diaper products. Hot melt adhesives are a plastic adhesive that is in a solid state at room temperature. It can be quickly bonded after heating and melting, and can be heated repeatedly. , Multiple bonding. Although the physical state of hot melt adhesive changes with temperature within a certain temperature range, its chemical properties remain unchanged, and it is non-toxic and tasteless, which is an environmentally friendly chemical product. The performance is stable, so it is convenient for storage and transportation.
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