With the improvement of people's material living standards, household paper has rapidly become one of the most closely related consumer goods in modern life. The production and consumption level of household paper is not only a symbol of the quality of life of the people of a country and the technical level of the paper industry, but also a symbol of civilization. As a kind of household paper, absorbent paper is mainly used in sanitary napkins, diapers, pet shops and as a composite core. It is mainly used to wrap fluff pulp, and the quality of fluff pulp wrapping mainly depends on the permeability of absorbent paper. Permeability affects the uniformity of fluff pulp. The better the permeability, the more uniform the fluff distribution. This paper discusses the methods to improve the air permeability of wrapping tissue from the three processes of beating, paper machine and slitting.

1.Pulp beating section of Absorbent paper

(1) Slurry ratio

Long fiber wood pulp has long fiber length, good interlacing ability between fibers and good paper strength, but the combination between fibers is not too tight and the fiber gap is large, so the air permeability between fibers is good; Short fibers are short, tight when interwoven, and small gap. Although the short fiber can improve the uniformity and softness of the paper, the air permeability is poor. Therefore, when batching, theoretically speaking, when the proportion of long fiber is large, the air permeability of the paper is better. By keeping the beating method unchanged, changing the size ratio and summarizing the actual production data, it can be concluded that properly increasing the proportion of long fibers can indeed improve the permeability of absorbent paper.

(2) Beating degree

As an indispensable process of papermaking, the impact of beating on the air permeability of the paper can be obtained through experiments: under the same paper weight, three disc mills are used for beating. The beating degree is high, the wet weight is small, and the air permeability of the paper is relatively poor. Two disc mills are used for beating. The beating degree is low, the wet weight is high, and the paper permeability is relatively good. The reason is that the beating degree is high, the fiber is cut thoroughly, the wire separation brooming is more obvious, and the specific surface area of the fiber increases more. Therefore, the combination between the paper fibers is good, the compactness is high, and the gap between the paper layers is reduced. The loose thickness of the paper sheet is low, so the air permeability is poor. According to practical experience, when the beating degree of the pulp is 20-21 ° Sr, it can not only ensure the required strength of the base paper, but also have good air permeability and reduce the power consumption.

2.Paper machine section of absorbent paper

(1) Elongation

The larger the elongation of the paper, the more fluffy, and the better the air permeability. Therefore, in the actual production process, properly increasing the elongation of the paper can improve the air permeability; Compared with the steel knife, ceramic knife can slightly improve elongation and thus increase air permeability. Therefore, the permeability of absorbent paper can be improved by changing the type of scraper.

(2) Pulp network speed difference

Changing the speed difference between pulp and mesh can change the characteristics of paper forming. Within a certain range, with appropriate increase, the horizontal combination of paper sheets is better, and the combination of fibers is more compact. When the horizontal tension is large, the permeability is poor. Therefore, in actual operation, under the condition of meeting other requirements, properly reducing the speed difference between pulp and mesh can improve a certain degree of permeability.

(3) Press specific pressure

In the process of pressing, with the increase of the specific press, the tightness of the paper increases, and the fiber gap becomes smaller, which will inevitably affect the air permeability. In order to improve the air permeability, it can be considered to reduce the press specific pressure and improve the drying efficiency.

3.Cutting section of absorbent paper

In the process of slitting the paper, the speed ratio of the slitter will also affect the air permeability of the paper. If the tension is too tight, the air permeability of the tray paper will increase by 2-3 seconds compared with that of the base paper. Therefore, during the slitting process, the speed ratio of the slitter should be reduced as much as possible to avoid affecting the permeability of the absorbent paper.

To sum up, in the production process of absorbent paper, the amount of long fiber can be appropriately increased, and in the beating process, on the premise of ensuring the paper strength, the beating degree of pulp can be appropriately reduced, and 3 disc mills can be changed to 2; In the production process of the paper machine, the elongation of the paper sheet can be properly increased. Under the condition of meeting the tension, the ceramic knife is used; Under the condition of ensuring the horizontal tension, properly reduce the speed difference between the pulp and the mesh; By properly reducing the specific pressure of the press, the above methods can improve the air permeability of the wrapping tissue.