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The effect of heat sealing temperature of PVC bag making machine

Time:2019/9/15Author:adminClick: 258
In the bag making process, the PVC bag making machine requires a heat sealing temperature, and its function is to heat the adhesive film layer to a more ideal viscous flow state. When selecting the heat sealing temperature, the demand is summarized based on the characteristics of the heat sealing material, the thickness of the film, the number of times of heat sealing and hot pressing, and the size of the heat sealing area. If the number of hot pressing of the part is added, the temperature can be appropriately lowered. If the heat sealing area is increased, the heat sealing temperature can be adjusted.



Since PVC plastic is an amorphous polymer and has no fixed melting point, as long as a molten temperature scale, that is, a temperature region between the solid phase and the liquid phase, when heated to this temperature scale, the film will melt. status. The upper and lower limits of the temperature scale represent the decomposition temperature and viscous temperature of the PVC, respectively. The difference between the two is the key to determining the difficulty of heat sealing.



In the bag making process of PVC bag making machine, the heat sealing strength is affected by the heat sealing temperature. The higher the heat sealing temperature, the heat sealing strength will be added, but the heat sealing strength will not change until the temperature is certain. If the heat sealing temperature is too high, the heat sealing material at the welded portion will be damaged, and the heat sealing strength of the sealing and the impact resistance of the bag will be lowered. Therefore, the heat sealing temperature is higher than the melting temperature of the heat sealing material, and the temperature should not be too high.



That is to say, if the number of hot pressing times of the same part is added, the temperature can be appropriately lowered; if the heat sealing area is increased, the heat sealing temperature can be adjusted. The more bag making material used in the bag making machine is PVC plastic, which is an amorphous polymer, so there is no fixed melting point, as long as a melting temperature scale is also a temperature between the solid phase and the liquid phase. region.

When the PVC bag making machine heats the PVC plastic to this temperature scale, the film will enter a molten state and then contribute to the forming of the bag. At this time, the upper and lower limits of the temperature scale represent the decomposition temperature and the viscous flow temperature of the PVC, respectively, and the difference between the two is the key to the difficulty of heat sealing.