At present, the structure of sanitary products is multi-layer non woven, which is made by composite processing. The surface layer of sanitary products in contact with human skin, followed by the guide layer, absorption core layer, support layer and anti side leakage layer. Each layer of non woven fabric has different properties.
The surface layer contacts the user's skin. When the user's body fluid is discharged, the surface layer first contacts the body fluid. However, the surface layer has no ability to absorb liquid. Its key function is to transport the liquid to the interior of the material. Therefore, the surface layer should have excellent liquid conduction and water permeability to keep the skin dry and fresh.
At present, the surface layer of sanitary products sold on the market is usually soft hot air non woven. This material uses es two-component fiber. The fiber is combed into a net, thermally bonded and reinforced to form es hot air nonwoven material with high fluffy, good permeability and soft touch. The excellent performance of this material is attributed to its stable three-dimensional structure and good resilience. The pores in the space can absorb and store liquids more than 10 times their own weight. Connecting the pores can promote the rapid transmission of urine, so that the material has excellent liquid dredgeability.
The guide layer is a special non woven layer, which is located between the surface layer and the absorption core. It has the characteristics of hydrophilicity, fast liquid penetration speed, good liquid diffusion and so on.
At present, hot air nonwovens are generally used as the guide layer. Although the price is slightly higher, it has been widely used because of its high fluffy degree, excellent liquid absorption performance and good impermeability. It is the mainstream material in the current diversion layer material market.
The absorption core layer is the key material of diapers, and its liquid absorption effect directly affects the quality of sanitary products. This core layer structure is characterized by double-layer non woven wrapped with a certain quality of superabsorbent materials.
In order to achieve the design goal of high liquid absorption core, a thin layer of nonwoven material is added to the middle layer of the traditional core structure, and SAP particles are compounded with the material using hot melt adhesive. The design principle of this structure is to use a large number of polymer materials to ensure the liquid absorption effect. After liquid absorption, the whole body expands and adheres to the glue smoothly without lumping. After liquid absorption, the original shape can still be maintained. However, this kind of core layer has the defects of poor permeability and high industrialization cost.
In recent years, prefabricated multi-layer cores have emerged. Its refined layering technology can effectively improve the absorption of the core, and each layer of polymer plays the role of absorption, diversion, diffusion, water locking and so on. The prefabricated multi-layer core has up to 8 layers, of which 3 layers are uniformly distributed water absorbent polymers, and the content can reach more than 70%. After the core absorbs urine, the water absorbent polymer with a very high content can firmly lock in the water, which is not easy to reverse osmosis, so as to achieve long-term dryness. The structural layer with more prefabricated cores does not affect the lightness, softness and permeability of the cores.
The function of the bottom support layer is to prevent urine leakage. In the early stage, sanitary products mainly used plastic film with good sealing as the supporting layer, and later often used breathable microporous film as the supporting layer to improve the permeability of the material. Some enterprises use the composite of dry paper and breathable bottom film as the supporting layer to improve the softness, but the industrialization cost of composite materials is high.
At present, spunbonded non woven has become the main material of the support layer because of its low cost and good wear resistance, which can be very soft and thin.
The anti side leakage edge layer of sanitary products in contact with the leg mouth is generally smsnon woven, which has high hydrostatic pressure resistance. Its water repellent finishing is to coat a layer of low surface tension lotion on the surface of the material, so that water droplets cannot penetrate the coating to achieve the water repellent effect. However, the water repellent SMS material processed by this method is very hard, and the user's legs are prone to redness and swelling. At present, the current products use the elastic bandage with wrinkles as the side leakage barrier of the leg opening. This material has soft texture, excellent mechanical properties and high fit with the user's body.
With the improvement of people's social life quality, the scale of China's sanitary products industry continues to expand. Understanding the structure of sanitary products and the characteristics of non woven used will help the non woven fabric industry develop better.