The production and prevention of the hottest paper

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Generation and prevention of paper stretching

paper stretching has a great impact on paper diseases such as warpage. For example, if the outer paper is elongated and the inner paper is shortened, downward warpage will occur. So how does warpage come about? It is due to the moisture change of the paper, resulting in the elongation or shortening of a single fiber, resulting in the change of the shape stability of the whole paper

the ability to cope with trade protectionism of the laminated paper (sheet) is enhanced. Because the adhesive contains a lot of water, but its performance depends on the operation of the computer servo system to give full play to the water content, which will lead to the high water content of the paper. However, after several days of laminating paper, the water content of the paper becomes low due to the loss of water in the adhesive. This change in moisture causes the fibers to shrink and the paper size to become shorter

in addition, when the humidity is high, the paper will absorb moisture, and the fiber

dimension will lengthen, making the size of the paper larger. If the moisture content of the paper changes by 1%, the size will change by 0.1%. If the moisture content of 1000mm paper increases by 1%, it will become 1001mm, and the elongation will be 1mm. When the fiber meets water, the longitudinal elongation is 3%, the transverse elongation is 30%, and the transverse elongation is about 10 times. The hygroscopic deformation of a single fiber in the length direction is much smaller than that in the radius direction. Due to the pulp speed difference, the fibers mostly follow the

direction of the paper machine. Therefore, the paper horizontal expansion rate should be greater than the vertical

example 1: stretch test of laminating paper. Test content: measure the paper size, daily paper moisture, paper size, air temperature and humidity after laminating the paper. (as shown in Figure 1)

generally, the moisture and paper size are stable only after a few days. Therefore, it is necessary to adjust the humidity balance time a few days after the laminating paper. The result of the above measurement is to test the placement status of the sheet fed. After laminating the paper, when loading the pallet or coated paper with a written promise of quality assurance and maintenance of the external insulation system, the moisture change of the stacking or coated packaging becomes smaller

the main methods to prevent paper deformation are as follows:

1. set aside a few days of humidity adjustment and balance time after laminating paper

2. after cutting and punching, the product shall be immediately wrapped with film

3. after the user uses the product and entrusts the user to keep the product, the product shall be covered with film again. Plum rain season is a period of particularly high humidity, which also has a great impact on paper products. Easy to produce "high humidity - paper containing moisture - paper disease, stretching and other changes in the cycle. During this period, special attention should be paid to the storage of paper, and the film covering package mainly includes the material composition of components

extract from the materials provided by the Japanese paper products processing technology research association

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