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The effect of heat sealing temperature of PVC bag making machine

Time:2019/8/10Author:adminClick: 177
The PVC bag making machine requires a heat sealing temperature during the bag making process, and its function is to heat the adhesive film layer to a more ambiguous viscous flow condition. When selecting the heat sealing temperature, the demand should be considered according to 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 points is approved, the temperature can be appropriately lowered. If the heat sealing area is increased, the heat sealing temperature can be adjusted.

 Because PVC plastics are attributed to amorphous polymers, there is no fixed melting point, so as long as a melting 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. The situation. The upper and lower limits of the temperature scale represent the differentiation temperature and viscous temperature of the PVC. The difference between the two is the key to determining the difficulty of heat sealing.

 In the bag making process of PVC bag making, 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 at a certain temperature, the heat sealing strength will not change. If the heat-sealing temperature is too high, the heat-sealing data at the weld will be damaged, and the heat-sealing strength of the seal 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 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, which helps the bag to be formed. At this time, the upper and lower limits of the temperature scale represent the differentiation temperature and viscous temperature of the PVC, and the difference between the two is the key to determining the difficulty of heat sealing.