Since the top layer is the outermost part of the diaper pails that is in direct contact with human skin, domestic and foreign diaper roll top layer research literature focuses more on whether the top layer can degrade rapidly, the comfort and safety of the top layer during wearing, and whether it can cause skin problems.

Patent No. 3,929,135 to Thompson. In order to achieve the effect of diaper pails rapid absorption, the hydrophobic fiber enhances the capillary effect of the surface layer, so that the urine can be quickly transferred down the surface layer. In order to reduce the rewetting of the surface layer, Procter & Gamble has developed a surface layer material with a large number of small holes larger than 0.1mm2 on the surface and an opening area of ​​12%; at the same time, the surface is also coated with an appropriate amount of skin care lubricant to enhance the softness and comfort of diaper pails protection performance. Japan's Unicharm has applied for a patent for a hygienic absorbent product. A layer of low-density PE filaments arranged in parallel is laid on the composite ES fiber net, and a three-dimensional wave structure is obtained through an embossing device with a special concave-convex structure on the surface. The surface layer of this structure can effectively enhance the liquid-conducting effect and reduce the re-seepage. Chinese patent 200510059408.7 introduces a non-woven surface material with a concave-convex structure, the convex part of which directly contacts the human skin, effectively reducing the contact area between the surface and the skin, and improving the dryness of the diaper pails during wearing; in addition, the surface layer It has a double-layer structure, which forms a space that is conducive to the downward transmission of liquid, accelerates the downward penetration of liquid, and improves the impermeability and conductivity of the surface layer.

The research on the surface layer of the above-mentioned patents mainly focuses on how to improve the liquid absorption rate and impermeability. As people's requirements for diaper pails no longer meet the basic functions, the research on antibacterial surface layers has begun to attract the attention of relevant researchers. Yuan Chuangang et al. used ES, Lyocell and chitin fibers to obtain a surface layer material with antibacterial properties. Huang Kui et al. used 60% bleached cotton and 40% chitin fiber as raw materials, and made a biodegradable and antibacterial non-woven surface material through a spunlace reinforcement process. This antibacterial surface layer has high safety, can absorb odor, and maintain a good microclimate and comfortable state on the skin surface, but it has low antibacterial properties and high raw material cost.

Subsequently, SungHoonJeong et al. immersed the ES (PE/PP) nonwoven material in a silver ion antibacterial finishing agent for antibacterial finishing, so that the nano-silver particles were uniformly dispersed on the fiber surface of the material, thereby obtaining a diaper pails antibacterial surface layer. Patent Nos. 201910380539.7 and 201710973207.0 disclose antibacterial ES fibers for hot air non-woven surface layer materials. The core layer of the fiber is a high-melting polymer, and the skin layer is a low-melting polymer containing a composite antibacterial agent. The former uses chitin, silver nitrate and nano-silver as composite antibacterial agents, and the latter uses modified porous graphene as the skeleton material. The diaper pails antibacterial surface layer is made of antibacterial ES composite fiber, and the antibacterial rate against Escherichia coli and Staphylococcus aureus is as high as 99.5% and 98.9%, respectively, and the antibacterial effect is lasting. Although this antibacterial non-woven surface layer has excellent antibacterial properties, its antibacterial components exist on the surface of the material, which directly contacts human skin during use, which poses a safety risk.