Factors Affecting Down Tissue Breathability

Down tissue is a special type of tissue paper and plays an irreplaceable role in disposable sanitary products. Currently, it is mainly used in the covering paper of composite cores such as sanitary napkins and diapers, and has the effect of accelerating liquid absorption and diffusion. . As the wrapping paper for the core, its own air permeability directly affects the air permeability of the core layer after water absorption. At the same time, the higher its air permeability, the faster the water absorption speed and the better the diffusion performance. Therefore, the research on the air permeability of down tissue paper has practical guiding significance.

1. The effect of the ratio of softwood pulp and hardwood pulp on the air permeability of down tissue

The down tissue is mainly made of bleached kraft softwood pulp, and a certain proportion of hardwood pulp is added. Softwood pulp has long fibers and good interwoven ability between fibers. In the case of high wrinkle rate and elongation rate It can still maintain a large tensile force. Because the beating degree is relatively low, the fibers are not tightly combined, and the fiber gap is large, so the air permeability between the fibers is good, and the hardwood pulp fibers are shorter and contain more hemicellulose, which enhances the binding force between fibers. Short fibers can improve the evenness and softness of the paper sheet, but the air permeability is poor. Through experiments, it is concluded that when the ratio of softwood pulp reaches 70, the physical index can meet the requirements, and the air permeability of the finished paper is high.

2. Effect of softwood pulp beating on air permeability of down tissue

A reasonable beating process is the key to ensuring the physical indicators of the finished paper. The absorbent lining paper is generally beaten by long and short fibers. Softwood pulp needs to be cut and split to a certain extent due to the long single fiber. Hardwood pulp Due to the short fibers, only for dispersing, try to disperse the fibers without cutting them. Therefore, the beating effect of softwood pulp directly affects its air permeability. Through experiments, it is concluded that when the beating degree is 25~27°SR, the air permeability of the paper is the largest, and the power consumption is saved.

3. Effects of softwood pulp species on air permeability of down tissue

The selection of raw materials plays a crucial role in the performance of paper sheets. Various physical indicators of the finished paper depend on the fiber morphology, such as cell wall thickness, cell cavity diameter, content of miscellaneous fibers, and microstructure of fiber walls. Therefore, both tensile force and air permeability should be taken into account, and appropriate raw materials should be selected to improve the air permeability of down tissue.

4. The effect of elongation on the air permeability of down tissue

In view of the unique wrinkling and elongation of tissue paper, the bulkiness of the paper sheet is increased, the tightness and stiffness are decreased, and the fiber interlacing is damaged. Infiltration, and increased the number and size of pores, air permeability has been improved. Therefore, higher air permeability can be obtained under the condition of higher wrinkling rate and elongation rate, but the production efficiency is reduced. of air permeability. Therefore, appropriately increasing the elongation rate can improve the air permeability of the down tissue.

With the help of production practice, through the discussion of the factors affecting the air permeability of down tissue, the following conclusions are drawn: (1) The main factors affecting its air permeability are not only related to the type of fiber raw material softwood pulp, but also related to the composition of softwood pulp in the papermaking process. It is related to process parameters such as ratio, beating degree and elongation of finished paper. (2) Select softwood pulp with large fiber thickness, lower softwood pulp beating degree, higher softwood pulp ratio and larger elongation rate can improve the air permeability of finished paper. However, as the down tissue of the diaper core wrapping paper, in addition to physical indicators such as air permeability and strength properties, other appearance and hand feel also need to meet the requirements of post-processing, which must be comprehensively considered in the production process.