Analysis of Influencing Factors on Calender Quality of Printed Products

In calendering, the main factors influencing the calender quality of the printed matter are calendering temperature, pressure and machine speed.

First, the temperature î—¥ î—¥ calendering process, hot pressing, coating and cooling stripping at each stage should have a suitable temperature, in order to facilitate the coating of the main agent molecules on the printed surface of the secondary wetting, adhesion and penetration, and enhance the two The contact effect. Under certain temperature conditions, the plasticity of the coating film layer can be improved, and under pressure, the smoothness of the calendered surface of the printed matter is greatly improved. When the temperature is too high, the adhesion strength of the coating layer decreases, the deformation value increases, and the water content of the printed matter decreases rapidly. This is disadvantageous for the coating and stripping process. On the contrary, the hot pressing temperature is too low, and the coating layer is not completely plasticized. The secondary wetting, adhesion and penetration of the printed matter is insufficient, and the adhesion of the coating layer is poor, so the calendering effect is poor, and it is not easy to form an ideal film layer with high smoothness after calendering.

Second, the pressure î—¥ î—¥ coating in the dry film layer, the coating molecules are relatively loose arrangement, there are many tiny holes. When calendering, under certain temperature and pressure, the intermolecular movement is intensified, showing the volume change of the film. This volume and percentage change is called the compression ratio. It is the ratio of the volume of the paint layer that is reduced during pressurization to the original volume before the pressurization. The compression ratio is large, which is conducive to the formation of a smooth film layer on the coating surface; on the contrary, the paint layer is With a small amount of compression, it is not easy to form a smooth film on the surface. However, if the pressure is too high, the printability and plasticity of the printed matter will be reduced, resulting in breakage.

Third, the speed î—¥ î—¥ glazing film surface smoothness and adhesion strength generally increase with the increase of curing time, but the rate of increase is getting smaller and smaller, after reaching a certain value will no longer increase. The length of the curing time depends on the calendering speed. When the glazing coating is in contact with the glazing tape, its molecular mobility gradually decreases as the coating temperature decreases. For example, if the curing time is short and the weakening speed is fast, the ink layer on the surface of the coating molecular print cannot fully function, the adhesion strength of the paint layer to the ink layer is poor, and the smoothness of the film surface after drying and cooling is low.
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Before calendering, the calendered steel strip must be cleaned, wiped, and leveled so that the strip remains slid, clean, and uniformly pressed. In calendering, the temperature, pressure, and speed of calendering are reasonably determined after comprehensive consideration based on the type of glazing coating and the glazing suitability of the printed lining.