After the heat-sealing material is determined, the heat-sealing quality of the composite packaging bag is directly related to the heat-sealing process, and usually the main control is the heat-sealing temperature, pressure and time.heat sealing theoryWhen the composite packaging bag is heat-sealed above the heat-sealing temperature, the plastic film becomes a viscous fluid state; while the heat-sealing pressure causes the interface molecules of the plastic film in a viscous fluid state to generate mutual penetration and diffusion external power; a certain heat The sealing time will make the interface molecules of the plastic film penetrate and diffuse each other as soon as possible, so that the interface disappears and becomes a whole, so it has good sealing.Heat sealing temperatureThe minimum heat-sealing temperature of the heat-sealing material depends on the melting temperature of the material. The heat-sealing temperature should be higher than the melting temperature of the heat-sealing material. However, the higher temperature depends on whether the material being sealed is a single film or a composite film, the thickness of the film, Heat sealing pressure, heat sealing speed and other technical indicators. Generally, the heat-sealing pressure is high; the heat-sealing speed is slow; the film thickness is large, the heat-sealing temperature can be lower, and vice versa.Heat sealing pressureThe heat-sealing pressure also has a great influence on the heat-sealing effect. The heat-sealing pressure should be appropriate. When the heat-sealing pressure is too low, it is difficult for the two layers of materials to be heat-sealed to achieve real fusion, or it is difficult to drive out the gas in the middle of the seal. As a result, local leakage is caused. The heat-sealing pressure is too high, and when the heat-sealing temperature is slightly higher, the heat-sealing knife will easily squeeze the melt in the seam during heat-sealing, resulting in”eagerly”Phenomenon. If it is mild, the heat sealing strength of the seal will be reduced, and the impact strength of the seal will be reduced. Generally, the heat-sealing temperature is high; the heat-sealing speed is slow; the film material is thinner, and the heat-sealing pressure can be smaller, and vice versa.Heat sealing timeUnder the same heat-sealing temperature and heat-sealing pressure, the longer the heat-sealing time, the stronger the interface bonding of the heat-sealing layer will be. However, if the heat-sealing time is too long, the resin at the sealing seam will be oxidized, which will reduce the heat-sealing effect. At the same time, if the heat sealing time is too long, it will easily cause wrinkling and deformation of the sealing seam, which will affect the appearance and cause leaky bags.summaryIn short, different heat-sealing materials and adding different additives and different processing methods (corona, printing) for composite packaging bags of heat-sealing materials, etc., the characteristics of heat-sealing materials are different. Choose carefully according to different packaged objects and packaging processes.Temperature, pressure and time are three important parameters to determine the heat-sealing process, which should be properly determined according to different heat-sealing materials and packaging processes of composite packaging bags to obtain the best heat-sealing effect.