There are many factors affecting the binding force of fibers. Besides the main influencing factor of pulping, it is closely related to factors such as the type of raw materials, the chemical composition of fibers, the length and physical properties of fibers, the arrangement of fibers in the paper sheet, the use of additives, and the Round Wire Woven Dryer Screen adopted in the subsequent drying process. The specific description is as follows:
1.The influence of raw materials
The physical structure and chemical composition of different types of raw materials vary greatly. Generally speaking, chemical wood pulp has the strongest binding force, followed by cotton pulp, then grass pulp, and mechanical pulp is the worst. Although the binding force of cotton fibers is not the greatest, due to their good strength, long length and strong surface interweaving force, the strength of the paper made from them is relatively high, and the tear resistance of the paper sheet is particularly good. It is worth noting that the characteristics of raw materials can also indirectly affect the subsequent drying efficiency. For example, the paper sheets formed from cotton pulp fibers have better compatibility with the Round Wire Woven Dryer Screen, which can reduce the loss of fiber bonding force during the drying process.
2. The influence of hemicellulose
The content of hemicellulose has a significant impact on the binding force. As the molecular chain of hemicellulose is shorter than that of cellulose, it has many irregularly arranged side chains and no crystalline structure. Its hydrophilicity is very strong. During pulping, it is easy to absorb water, swell and fine fibrous, increasing the specific surface area of the fibers and releasing more hydroxyl groups. Therefore, it is conducive to improving the strength of the paper. Especially in the early stage of pulping, the improvement in bursting strength and tensile strength is more obvious. When the pulp containing a relatively high amount of hemicellulose is formed, under the uniform drying effect of the Round Wire Woven Dryer Screen, the hydroxyl groups between the fibers are more stable, further consolidating the advantage of binding force.
3. The influence of cellulose
The content of cellulose and the degree of polymerization also affect the binding force of fibers. Fibers with a high cellulose content and a large degree of polymerization have better strength and greater binding force when made into paper. Conversely, the binding force of the fibers is relatively small. It is generally believed that for paper types with high requirements for strength and density, such as carbon paper, capacitor paper, and banknote paper, raw materials with high cellulose content and high polymerization degree should be selected. For this type of high-end paper, a high-precision Round Wire Woven Dryer Screen is usually selected in the drying process to avoid the decrease in fiber bonding force caused by uneven drying. Conversely, if the paper quality is poor or for general printing paper, raw materials with a lower degree of cellulose polymerization can be selected.
4. The influence of lignin
Pulp with a high lignin content has poor hydrophilicity, is difficult to pulp, and has a low binding force between fibers. The resulting paper has a small density and poor strength. This is because lignin is mostly distributed in the P and S layers, which affects the swelling and fine fiber formation of fibers. Mechanical wood pulp has a high lignin content, low bonding strength and poor paper strength. Meanwhile, paper sheets with a high lignin content are prone to uneven shrinkage during drying. However, the good air permeability of the Round Wire Woven Dryer Screen can alleviate this phenomenon and reduce the damage to the fiber bonding force caused by uneven shrinkage.
5. The influence of fiber length
There are two concepts of fiber length: the length of the fiber itself and the length of the pulp fiber after pulping. In production, it mainly refers to the length of the pulp fibers after pulping. The length of the fibers after pulping is determined according to the requirements of the paper type. Fibers that are too long are not good for the uniformity of the paper sheet. The length of the fibers has an important relationship with the strength of the paper, and its impact on tear resistance is particularly significant. When the binding force of fibers increases to a certain extent, the influence of fiber length on the binding force becomes more obvious. For mechanical wood pulp with a high lignin content, the binding force of fibers is poor, and the length of fibers is more important for the strength of papermaking. The interwoven structure formed by fibers of appropriate length in the paper sheet is more stable. When in contact with the Round Wire Woven Dryer Screen, the force can be evenly applied, and the binding force of the fibers is more uniform after drying.
6. The influence of additives
Adding hydrophilic substances such as starch, protein, carboxymethyl cellulose, and plant gum to the pulp can enhance the binding force of fibers. This is because the structures of these substances contain polar hydroxyl groups, which can strengthen the bond between fibers and make the bond between fibers more solid. Conversely, adding hydrophobic substances such as rosin, paraffin and fillers to the pulp will affect the bonding between fibers and reduce the strength of the paper. This is because the addition of such substances isolates the fibers from each other, reduces the contact surface of the fibers, and lowers the bonding force of the fibers. It should be noted that some additives may change the surface properties of the paper sheet. Selecting the appropriate Round Wire Woven Dryer Screen can prevent the additives from adhering to the mesh surface and ensure that the fiber bonding force is not disturbed by the drying process.
