The structure of sanitary napkins can be divided into surface layer, absorbent core, and bottom layer.
Hot-melt glue is used to bond each layer of material.
The surface layer is the part that is in direct contact with the skin. Its material is soft. The surface weave and indentation can affect the anti-osmosis effect (dryness) of the sanitary napkin.
PE perforated film surface layer and cotton surface layer are the two most commonly used materials. The PE surface layer plus the micro-porous design can make menstrual blood less easy to seep back and give users a dry feeling. However, the material is hard and some users will cause Allergic reaction; due to the improvement of cotton absorption design and the availability of perforated and composite materials, the market share after 2001 has gradually become higher than that of PE sanitary napkins.
The inner layer is mainly composed of high molecular polymer and high molecular polymer composite paper formed by cotton, non-woven fabric, pulp or a composite of the above materials, which is used to absorb menstrual blood flowing out. The side design is mainly used to prevent side leakage, because it will present a certain angle with the sanitary napkin body when it is used, and it is easier to rub against the groin area. Therefore, sanitary napkins with soft material sides are more favored by women. The backing glue of the sanitary napkin is an impermeable material, which can keep menstrual blood in the sanitary napkin. In the 70s and 80s, a self-adhesive backing adhesive was developed to facilitate the fixing of the sanitary napkin on the underpants.