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Analysis Of Heat Sealing Of Flexible Packaging Lamination Bag
Jul 11, 2017

Soft package Lamination Bag heat sealing failure analysis:

1, the type of heat sealing layer material, thickness and material quality on the heat sealing strength is the most direct.

General composite packaging commonly used heat sealing materials are CEP, LPPE, CPP, OPP, EVA, hot melt adhesives and other ionic resin co-extruded or blended modified film. The thickness of the heat seal layer material, typically between 20-80 μm. Special circumstances also have up to 100-200μm, a unified heat sealing material, the heat sealing strength increases with the heat seal thickness increases.

In the actual production process, because of heat sealing pressure, bag speed and composite substrate thickness and other aspects of the actual use of the heat sealing temperature is often higher than the heat sealing material melting temperature. The smaller the heat sealing pressure, the higher the heat sealing temperature, the faster the machine speed, the thicker the composite film surface layer material, the higher the required heat sealing temperature. If the heat sealing temperature is lower than the softening point of the heat sealing material, the heat sealing layer can not be sealed in any way, if the pressure is increased or the heat sealing time is increased. However, if the heat sealing temperature is too high, and easy to damage the welding edge of the heat sealing material, melt extrusion produce "root cutting" phenomenon, greatly reducing the sealing heat sealing strength and Lamination Bag impact resistance. In the actual system of Lamination Bag process, the pressure of the heat sealing tool often used to adjust the rotating spring. Adjust the process of the general tool consists of two springs, divided left and right sides, if the pressure impact heat sealing strength, the detection method is: take a positive processing of the Lamination Bag carefully observe the seam, if the pressure is not angry And other phenomena, with a long 500px, width 75px, thick 5000px dedicated smooth bamboo test, because the pressure is not enough, low strength, often thrown phenomenon, so the average pressure and temperature is to reduce the low strength, Stratification of the basic one.

2, to achieve the desired heat sealing strength, heat sealing pressure is essential.

For thin bags, heat sealing pressure at least to reach 2kg / cm2, and with the overall thickness of the composite film corresponding increase; if the heat sealing pressure is insufficient, between the two thin film is difficult to achieve true fusion, resulting in local heat sealing is not good Or it is difficult to eliminate the air bubbles caught in the middle of the weld, resulting in Weld. But the heat sealing pressure is not the bigger the better, should not damage the welding edge is appropriate, due to the higher heat sealing temperature, the welding edge of the sealing material has been in the semi-molten state, too much pressure to squeeze the department heat seal Material, so that the edge of the weld to form a semi-blocked state. Welds are brittle, heat sealing strength is reduced, so the pressure adjustment is very hub.

3, heat sealing time is mainly determined by the speed of the bag machine.

Speed, heat sealing time is short; slow, heat sealing time is long. Heat sealing time is also a factor affecting the strength and appearance of weld sealing. The same heat sealing temperature and pressure, the heat sealing time is long, the heat sealing layer fusion more fully, combined with more solid; but the heat sealing time is too long, easily lead to wrinkle deformation of the weld, affecting the flatness and appearance. After the heat sealing of the weld if the cooling is not good, not only will affect the appearance of the soldering problem, but also on the heat sealing strength has a certain impact, the cooling process is through a certain pressure, with a lower temperature on the just melting heat The sealed weld is shaped. Therefore, the pressure is not enough, cooling and reincarnation is not good, the amount of reincarnation is not enough, the water temperature is too high or cooling is not timely, will cause poor cooling, heat sealing strength.