2. Binder is a special material containing solvent. Under certain technological conditions, it is coated on the dark side (or smooth side) of the original aluminum foil and dried through the drying path to form a bonding layer, which plays a decisive role in the heat sealing strength of the hot sealing of aluminum foil.
3. Under the control of certain technological parameters in production process, the adhesive is coated on the surface of the original aluminum foil, and the quality of the film will directly affect the hot sealing of aluminum foil of the product. Among them, the most important parameters include the speed of coating, the sectional temperature of drying path, the shape, depth, number of lines and the position and angle of the scraper of the coating roll. The coating speed determines the drying time of the coating in the drying channel. If the coating speed is too fast and the drying temperature is too high, the solvent volatilization on the surface of the film will be too fast, resulting in residual solvent in the film. The film drying will not be sufficient, and it will be difficult to form a dry and firm adhesive layer, which will affect the hot sealing of aluminum foil the product and cause adhesion between the product layer and the layer. The thickness and uniformity of the coating film are determined by the shape, depth, number of lines and the position and angle of the scraper. If the selection or adjustment is not appropriate, the adhesives can not be uniformly coated on the surface of the original aluminum foil, resulting in non-uniform film formation, the thermal sealing effect of the product will not be good, and the strength will also be affected.
4. The heat seal temperature is an important factor affecting hot sealing of aluminum foil. The temperature is too low to make the bonding layer seals well with the PVC film, and the bonding between the bonding layer and the PVC film is not firm. If the temperature is too high, the seal will be affected. Therefore, the reasonable heat sealing temperature is usually between 160 ~180 C.
5. To achieve the ideal heat seal strength, a certain heat seal pressure should be set for hot sealing of aluminum foil. If the pressure is insufficient, not only can the adhesive layer of the product and PVC film not fully adhere to the heat seal, but also can the air bubbles remain between the two, so that the good heat seal effect can not be achieved. Therefore, the national standard stipulates that the pressure of the hot sealing of aluminum foil is 0.2*10 Pa.
6. Sealing time and time also affect the hot sealing of aluminum foil. Usually, under the same heat sealing temperature and pressure, a longer heat sealing time can make the heat sealing parts more solid and perfect, and can better achieve the expected heat sealing strength. If the heat sealing time is too short, the heat sealing between the adhesive layer and the PVC film will be insufficient. Therefore, the national standard stipulates that the scientific heat sealing time is 1 s.
