How to defuse the bending and warping of the hotte

2022-08-06
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Cardboard warping, hardening and low strength always occur. How to defuse them skillfully

release date: Source: Huayin carton editor in charge: number of views of package: 1982 copyright and disclaimer

core tips: what is the relationship between the four properties of paperboard such as warping, water absorption, hardness and moisture content of paperboard, and surface strength of paperboard and printing quality? Is there any way to avoid it? First, let's listen to the experts of China India

[China Packaging News] what is the relationship between the four properties of paperboard such as warping, water absorption, hardness and moisture content of paperboard, and surface strength of paperboard and printing quality? The maximum force that the fixture of hydraulic universal testing machine can bear must be greater than or equal to the maximum experimental force of the host. Is there any way to avoid it? First, let's listen to the experts of China India

paperboard warping

paperboard warping refers to the fact that the paperboard is convex or concave in a large range. Using warped cardboard to make cartons, the forming cannot be square, affecting the appearance, and the compressive strength is unstable. The warped paperboard is not easy to accumulate and can not smoothly enter the printing machine, which seriously affects the printing chromatic effect and the accuracy of slotted die cutting. It is generally required that the bending and warping of paperboard shall not exceed 15 ‰ on the high-altitude operation platform jg/t5101 ⑴ 998. For example, the bending height on the length of 1m shall not exceed 15mm. Therefore, in the production process, it is necessary to separate the warped cardboard from the flat cardboard. The warped paperboard shall be produced by folding line or steam jet flattening

water absorption of paper

the absorption of ink by paper mainly depends on the tightness between the paper fibers (the size of the gap). When the gap between the paper fibers is small, the effect of the fiber capillary is affected due to too few broomed fibers, resulting in the reduction of the paper's absorption of ink; If the gap between the paper fibers is too large, the ink and pigment will be absorbed together due to excessive absorption of connecting materials, resulting in the phenomenon of through printing. Whether the paper can be used for printing smoothly and with high quality depends on the printability of the paper. The requirements of printing on paper are as follows: the hue of paper shall reach the purity of color and luster of the same texture as far as possible; The dust degree of the paper shall not exceed the allowable range, with the minimum light transmittance and the mechanical strength to ensure normal printing; Zhoushaoxiong, deputy chief engineer of China Steel Research Technology Group Co., Ltd., pointed out that the paper thickness and tightness should be the same in the same printing batch; The paper edge shall be right angle and the slope error shall not exceed ± 3mm

hardness and moisture content of paperboard

during the storage, printing and other processes, the paper will change due to the different joints of PP, ABS and other materials used in the surrounding environment. For example, under the action of external force, it will change its shape and size instantaneously, and when the external force stops, the paper will return to its original shape and size. This deformation process is called sensitive elastic deformation; When the paper is subjected to external force, it changes its shape and size within a certain time interval. When the external force stops, it slowly returns to its original shape and size. This deformation process is called anelastic deformation; When the external force is cancelled, the paper still remains in the state of shape and size deformation caused by the external force, which is called plastic deformation. Sensitive elastic deformation and anelastic deformation are reversible deformation, while plastic deformation is irreversible deformation. The water content of paper directly affects the quality of printed matter. If the water content is too much, the strength of the paper will be reduced. Under the action of external force, the paper fiber will be pulled out, which will enhance the plastic deformation and affect the drying speed of the imprint; If the water content is too small, the paper will be brittle, easy to cause damage and generate static electricity

surface strength of paperboard

the surface strength of paper determines the wear resistance, powder dropping resistance and fuzzing resistance of the surface of paper during printing. In order to get a clearer point during printing, some high viscosity inks will be used. If the surface strength of the paper is not enough, it will be easy to lose powder and hair, and adhere to the surface of the plate; If the ink with low viscosity is used, the blank area of the printing plate will be dirty due to the emulsification of the ink and the fountain solution in lithography

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