Most complete compound bag heat sealing failure analysis, not to be missed!

This paper detailed the most comprehensive analysis of soft packing compound bag heat sealing, hope to help you to soft bag factory! 1, the heat sealing material type, thickness and material of the quality of the influence of heat sealing strength is the most direct. General commonly used heat sealing compound packing materials have the CEP, LPPE, CPP, OPP, EVA hot melt adhesive resin and other ionic co-extrusion or blending modified membrane. The thickness of the heat sealing material, generally 20 & ndash; Floating between 80 microns. Under special circumstances has 100 & ndash; 200 microns, the same kind of heat sealing material, the heat sealing strength increases with the thickness of the heat sealing. High temperature cooking bags, for example, the heat sealing strength of general requirements of 40 & ndash; 50 Newton, therefore, the thickness of heat sealing should be in the 60 s & ndash; More than 80 microns. Heat sealing bag making the temperature in the process, the control of the temperature depends on the temperature meter to display them. In the process of heat sealing compound bag, as precise as possible to the requirement of thermometer, error range and the value is not greater than best & plusmn; 5℃。 Heat sealing temperature on the influence of heat sealing strength is the most direct, the melt temperature of various materials, directly determine the minimum heat sealing temperature compound bag. In the actual production process, due to the heat sealing pressure, bag making machine speed and the thickness of the composite substrate aspects of influence, the actual use of the heat sealing temperature tend to be higher than the melting temperature of the heat sealing materials. Heat sealing pressure is smaller, for heat sealing temperature is higher, the faster machine speed, the surface of composite membrane material is thicker, the requirements of the heat sealing temperature is higher. If the heat sealing temperature is lower than the heat sealing material softening point, no matter how to increase the pressure or heat sealing time, all can't make real sealing heat sealing layer. However, if the heat sealing temperature is too high, and easy to damage the welding side heat sealing materials, melting extrusion to produce & other; Root cutting & throughout; Phenomenon, greatly reduces the sealing heat sealing strength and impact resistance performance of composite bag. In the process of actual bag heat sealing, heat sealing tool can rotate the spring pressure often USES to adjust. General tool adjustment process is composed of two springs, left and right sides, if the pressure affect the heat sealing strength, testing method is: in a compound bag look carefully stitch is processing, if the pressure evenly won't produce the phenomenon such as bubble; Another method is to use long 500 px, 75 px, 5000 px wide smooth bamboo piece of experiment, due to the pressure is insufficient, low intensity, tend to appear leakage phenomenon, so the uniform pressure and low temperature is to reduce strength, one of the basic stratification. 2, to achieve the ideal heat sealing strength, heat sealing pressure is necessary. For thin bags, heat sealing pressure to at least 2 kg/cm2, and as composite membrane increases with the increase of total thickness; Jorge sealing pressure is not enough, difficult to achieve real fusion between two layers of thin film, lead to local heat sealing is bad or difficult to eliminate the bubbles sandwiched between weld, virtual welding. But heat sealing pressure is not the bigger the better, we should not to damage it is advisable to weld edge, because the high heat sealing temperature, welding and heat sealing materials are already in a molten state, too much pressure to squeeze out some hot sealing material, the weld edge forming half cut off state. Weld crisp, heat sealing strength reduced. So the pressure regulation is critical. 3, heat sealing time is mainly determined by the speed of bag making machine. Speed, heat sealing time is short; Slow speed, heat sealing time is long. Heat sealing time is of the look of the welding seam sealing strength and a key factor. Under the same heat sealing temperature and pressure, heat sealing time is long, the heat sealing layer fusion, more fully combined with stronger; But the heat sealing time is too long, easy to cause weld wrinkle deformation, affect the flatness and appearance. After heat sealing weld if cooling is not good, not only affect the appearance of weld suspected flatness, and has a certain strength of heat sealing, cooling process is through under certain pressure, with low temperature on the weld shapes after melting heat sealing. So the pressure is insufficient, cooling and circulation, circulation quantity is not enough, the water temperature is too high or not timely, cooling will cause poor cooling, heat sealing strength reduced. 4, heat sealing, the more the higher the heat sealing strength, longitudinal heat sealing number depends on the effective longitudinal welding rod length and the ratio of the bag length. Lateral heat sealing number by the lateral heat sealing device on the number of group decision. Good heat sealing for heat sealing number at least more than two times. The same structure and thickness of the composite membrane, composite interlayer stripping degree is higher, the greater the heat sealing strength; For low peel strength of composite products, weld damage is often a seam of composite membrane interlayer strip first, caused by the inside heat sealing layer independent damage under tension, and the surface material loss of reinforcing effect, the weld heat sealing strength thus greatly reduced; If composite interlayer stripping degree is strong, not ask welding side layer stripping, measured by the actual heat sealing strength, is much more people; For the PE or OPP in the inner heat sealing and heat sealing strength is much better than the same thickness of BOPP. 5, the influence of compound bag contents. Some products for the powder loading, easy contamination in filling sealing, for example, when using LDPE material as lining material, found pincer-like device is easy to break. This is because the LDPE for inclusion of heat sealing is not very good, would then replace the inner membrane materials or increase the thickness of the material can improve the intensity of heat sealing.