Understand the principle and function of pulp molding beating

2020-05-26 17:30:15

The principle of pulp molding and beating is to use physical (mechanical) methods to treat pulp fibers suspended in water, so that they have characteristics that meet the production requirements of pulp molding products forming machines, and make the produced paper molding products meet expectations. This process is called beating.

1. The principle of beating

After the pulp fiber is mechanically processed by the beating equipment, it becomes soft and plastic. Its principle is that through the action of the beating equipment on the fibers, the fibers are cut, crushed, swelled by water and fibrillated, so that the surface area of the fibers is increased, thereby increasing the bonding force between the fibers. As the beating progresses, the binding force of the fibers increases, but the average fiber length decreases. Practice has proved that some physical properties of paper products, such as folding resistance, burst resistance, water absorption, air permeability, etc., are closely related to the beating method. Therefore, when determining the beating method, a reasonable choice should be made according to the different requirements of pulp raw materials and paper products.

2. The effect of beating on fibers

The effect of beating on the fiber is mainly to make it undergo physical and chemical changes. No matter what type of beating equipment is used, the fiber will be cut, crushed, swelled by water and thinned. When the fiber is subjected to the above effects, the main changes occur on the cell wall of the fiber. The changes in the fiber cell wall have the following forms:

(1) Beating causes displacement and deformation of the fiber cell wall.

The microfibers at a certain position in the middle layer of the secondary wall are bent and deformed, and the gap between the microfibers is increased, which creates conditions for the fibers to absorb more water. and the outer layer of the secondary wall play an important role.

(2) Beating breaks the primary and secondary fiber walls.

(3) After beating, the pulp fiber absorbs water and swells. The fibers become soft and plastic, the external surface area increases, the internal organizational structure is relaxed, and the intermolecular cohesion decreases, which is conducive to the progress of fine fibrillation.

(4) Through the physical (mechanical) action of the beating equipment, the fibers are made into fine fibers. Due to the occurrence of fibrillation, the interweaving ability between fibers is enhanced, so that the physical strength of paper products is greatly improved.

(5) Due to the shearing action of the beating equipment, the fibers are cut transversely.

(6) The relationship between beating and the properties and strength of paper products.

Through the above content, do you have a simple understanding of the principle and function of pulp molding and beating? I didn't expect that a small pulp molding still needs such professional knowledge, principles and equipment!