As the core structure of toddler pants, the absorption core layer needs to have the characteristics of fast and uniform liquid absorption, large amount of liquid storage and flat structure after absorbing liquid. But at present, SAP particles are mainly used for absorbing core layer, and easy to form larger gel agglomerate after inhalation, which not only reduces the inhalation rate and multiple inhalation capacity, but also easily damages the structure and wears unevenly. Therefore, for the first problem, the multilayer gradient structure composite absorption core layer is used to improve the liquid absorption rate, impermeability and multiple liquid absorption. Aiming at the second problem, saf fiber is used to replace SAP particles for liquid absorption, so as to keep the structure of Walker pants flat after liquid absorption.
Fiber aggregates produce capillary water absorption, ie wicking, which is a dynamic osmotic phenomenon. Theoretically, the permeation process of nonwovens depends not only on the permeability of single fibers, but also on the structural dimensions of the material. Therefore, the wicking of nonwovens is not only affected by single fiber penetration, but also by the pore shape factor.
When the fibers of the nonwoven material and the contact liquid are constant, the pressure of the capillary is inversely proportional to the equivalent radius of the capillary. Therefore, when the pores between fibers are arranged vertically, due to the dual effects of penetration and gravity, the wicking will reach a certain height and form a balance; when the pores between fibers are arranged horizontally, the liquid will continue to expand under capillary action, forming unbalanced. When the shape and size of the pores or the composition structure are different, capillary pressure difference will be generated, resulting in the selectivity and directionality of expansion.
To sum up, the direction of capillary water absorption in textile materials always flows from large-diameter pores to small-diameter pores; at the same time, the liquid always transfers from low cos pores to high cos pores, that is, the liquid preferentially flows to the pores composed of fibers with good hydrophilicity. , the above two points are the directionality and selectivity of wicking.
Based on the theoretical basis of the above-mentioned wicking effect and capillary differential effect, a composite absorbent core layer with a multi-layer gradient structure was designed in this subject. The composite absorbent core layer includes three layers of non-woven materials, the average pore size gradually decreases from top to bottom, the hydrophilicity gradually increases, and the disorder degree gradually increases. Among them, the pore size and hydrophilic gradient structure can enhance the vertical direction of the composite core layer, improve the permeability of liquid in the vertical direction of toddler pants, and accelerate the absorption rate of toddler pants. At the same time, the third layer material (ie, the bottom layer) is the best, which can effectively lock the liquid. , to prevent reverse osmosis; the chaotic gradient structure can guide the vertical diffusion of the liquid along the composite absorption core layer, so that the liquid diffuses evenly in the composite absorption core layer, which has a significant effect on improving the utilization rate of the absorption core layer.
Among them, disorder refers to the uniformity of the number of fibers arranged in all directions of the fiber web. If the fibers are arranged in parallel in the web, the disorder is low; if the web is uniformly distributed in all directions, the disorder is high. The orientation of the fibers in the fiber web will affect the orientation of the pores between the fibers, thereby affecting the direction of liquid expansion.
Understanding the absorption principle and constantly optimizing the structure of the absorption core layer is helpful to the product upgrading of toddler pants.
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