In recent years, the changes in China's population composition have brought great development potential to China's diaper market. Absorbing core is the "heart" of diapers. This paper analyzes the traditional and new structure of absorbent paper.

1.Traditional fluff pulp absorbing core

The traditional fluff pulp absorbing core is mainly composed of coating, sap and fluff pulp. Sap and fluff pulp are mixed in a certain proportion to form sap/ fluff pulp absorber; The coating layer is made of toilet paper, nonwoven materials or double-layer composite materials. The upper coating layer should generally have the functions of flow diversion and air permeability, and the lower coating layer should generally have the functions of anti reverse osmosis and barrier.

Diapers containing traditional fluff pulp absorbing core absorb urine. Fluff pulp diffuses and conducts urine with the advantage of natural fiber. At the same time, SAP quickly absorbs, expands and locks urine. Among them, sap and fluff pulp are mixed loosely. There is enough space inside to breathe. Therefore, although this kind of diaper is relatively thick, it has good air permeability after liquid absorption: in addition, fluff pulp can fix sap to a certain extent, which can avoid the movement and accumulation of sap, and maintain the flatness and softness of the diaper surface; In addition, the wicking effect of fluff pulp can effectively solve the problem of gel blockage after SAP suction, weaken the easy lump of diapers after suction, and improve the comfort of wearing; However, when wearing this kind of diapers, the wearer should avoid large-scale movement or overturning, resulting in SAP slippage, resulting in uneven distribution. The part with more SAP distribution rapidly absorbs and expands, hinders the diffusion of urine, and finally causes faults and lumps, which affects the multiple liquid absorption of diapers, and even leads to the tearing of the surface film, urine leakage, and stimulation of the wearer's skin.

2.New composite absorbing core

With the lightweight development of diapers, people have higher and higher requirements for liquid absorption performance, and new composite absorbing cores continue to emerge. It generally uses the coating layer to coat the dust-free paper and porous fluffy nonwovens, and spreads SAP between the porous fluffy nonwovens, and uses hot melt adhesive to bond each layer.

In the new composite core, porous and fluffy nonwoven material is a hydrophilic material, and its grid structure can store and fix a large amount of sap, so that sap is evenly distributed. Therefore, the new composite core will expand as a whole after absorbing urine, avoiding faults and lumps after the core absorbs liquid, and the overall flatness of diapers is good. At the same time, because there is no fluff pulp added, the diapers containing the new composite absorbing core become very light and thin, reducing the wearer's sense of weight-bearing, and the amount of SAP added increases correspondingly, improving the liquid absorption of the diapers.

However, this kind of core also has some disadvantages, such as: without the support of fluff pulp, SAP will produce gel shape after absorbing urine, the touch of diapers will harden, and the permeability will be reduced; Hot melt adhesive is used between each layer of materials to fix sap, and the more sap, the more hot melt adhesive is required, resulting in harder touch and worse air permeability of diapers, affecting the liquid absorption speed, and the odor is heavier after liquid absorption; The ultra-thin composite core generally has the serious defects of faster liquid absorption speed at the first time and then lower liquid absorption speed, so it cannot have a more balanced liquid absorption speed as the traditional fluff pulp core; Its structure is complex and there are many layers. Compared with the traditional fluff pulp core, its production speed is lower and its production cost is higher.

At present, there is a large gap between the penetration rate of the domestic Diaper Market and that of developed countries. Therefore, the domestic market has a broad prospect. In order to better improve the market share of domestic diapers, we must solve the bottleneck of diapers absorbing core. Understanding the structure of absorbent paper is conducive to its better development.