Views:13 Author:Site Editor Publish Time: 2019-01-08 Origin:Site
Ring and edge compressive strength is an important criterion to measure the quality of corrugated paper. In the production process, the characteristics of corrugated base paper, the type of fiber raw material, the pulping and pulping process, the papermaking process, and the paper strength and moisture will affect the ring pressure strength of corrugated paper.
The characteristics of the corrugated base paper: the stiffness of the fiber, the bonding force between the fibers and other parameters will affect the stiffness of the base paper, further affecting the ring crush strength of the corrugated base paper. The stiffness of the sheet is mainly related to the thickness and the ability of the sheet to resist stretching and compression, that is, the modulus of elasticity. The thickness of the sheet has the greatest effect on stiffness and ring strength. When the quantification is certain, increasing the tightness is beneficial to improve the bonding force between the cardboard fibers, thereby positively affecting the crack length and the breaking resistance; the reduction of the thickness of the paper sheet will have a negative impact on the ring crush strength, when the fibers are inter When the improvement of the bonding force can not make up for the loss of the thickness of the ring pressure, the ring pressure strength will be greatly reduced, resulting in a decline in the quality grade of the corrugated base paper.
Types of fiber raw materials: Generally, the raw materials used for the production of corrugated base paper are wood, grass and waste paper. The corrugated base paper produced from wood pulp has better ring pressure strength than straw pulp, and finally waste paper. Foreign corrugated paper generally uses hardwood as raw material, and domestic corrugated paper is mainly waste pulp. However, if the various impurities adhered to waste paper are not purified, it will inevitably lead to a decrease in fiber bonding strength, resulting in a decrease in the ring pressure of the base paper. . Therefore, when using corrugated paper as raw material to produce corrugated base paper, controlling the ratio and using a reasonable pulp treatment process is the key to ensuring the ring crush strength of the corrugated base paper.
Papermaking process: The papermaking process has a great influence on the strength of the paper ring. Different papermaking conditions will result in different fiber arrangements in the formed sheets. The headbox type, sizing concentration, shaper, and dewatering elements all have an effect on fiber formation. At present, paper sheet making generally uses a round paper machine former and a long net paper machine head box. The thickness of the paper produced by the long net paper machine is relatively uniform, and the vertical and horizontal indexes of the physical strength are good, but the tightness is low. In the papermaking, the paper pulp should be fully dispersed, so that the paper sheet has good uniformity, and the pulp speed and the web speed should be coordinated. Otherwise, the longitudinal and transverse tension ratio of the paper sheet will be affected, and even the physical strength will be reduced.
Wet pressing is an important part of determining the structure and strength of the paper. Wet pressing is not only a good combination of paper layers, but also an important measure to control the tightness of the paper. If the wet press of the paper does not meet the requirements, air will remain in the paper, which will result in poor bonding between the wet paper layers. When the wet paper with bubbles between the layers reaches the drying section, the air bubbles will expand due to heat, which will result in paper formation. "delamination".
Paper strength and moisture are produced: the final strength of the paper is formed in the dryer section. For this reason, the operation of the dryer section has a great influence on the physical strength of the sheet. During the drying process, as the moisture of the wet paper sheet evaporates, the fibers constituting the sheet gradually come together and begin to tightly bond, thereby greatly increasing the physical strength of the sheet. Generally, an increase in the moisture content of the paper will result in a decrease in the ring pressure strength. Since the moisture of the paper changes with the relative humidity, the relative humidity has a significant influence on the physical properties of the paper, mainly reflected in the influence on the strength characteristics.
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