As we all know, the heat sealing effect of aluminum foil container has a direct impact on food storage. A study shows that an unqualified heat sealing index will have a bad direct impact on product quality. Thus, it is necessary to ensure a good heat sealing effect. That's the factors determine the heat sealing effect of aluminum foil container:
Heat sealing temperature is an important factor affecting the heat sealing effect. The reasonable heat sealing temperature is usually between 150℃ and 160℃.
The temperature is too low can not make the bonding layer and PVC film heat sealing, bonding layer and PVC film between the bonding are not firm. If the temperature is too high, the quality of the food will be affected.
Usually, under the same heat sealing temperature and pressure, longer heat sealing time can make the heat sealing part seal more firmly and perfect, and can better achieve the expected heat sealing strength.
However, the technological conditions of modern high-speed product packaging machine cannot provide a long time for heat sealing. If the heat sealing time is too short, then the adhesive layer and PVC film will be heat sealing is not sufficient. For this reason, the recommended heat seal time is 1s.
To achieve the ideal heat sealing strength, it is necessary to set a certain heating seal pressure. If the pressure is insufficient, not only can not make the product adhesive layer and PVC film fully adhere to the heat seal, even make the bubble stay between the two, not to achieve a good heat seal effect.
The adhesive is a special substance containing solvent, it is coated in a certain process condition in the original aluminum foil rough side (or smooth side), after drying to form a bonding layer, the heat sealing strength of the product plays a decisive role.
The aluminum foil material is the carrier of adhesive layer, its quality has a great impact on the heat sealing strength of products.
First, the surface of the original aluminum foil oil will weaken the adhesive and the original aluminum foil between the adhesive effect. If the original aluminum foil surface oil and surface tension less than 31×10-3 muon, it is difficult to achieve the ideal heat sealing strength.
And the metal composition of the original aluminum foil and the lack of surface luminosity affect the strength of heat sealing. Only by strictly controlling the quality of aluminum foil materials can the heat sealing effect of aluminum foil heat sealing film be guaranteed.
Under the control of certain technological parameters, the adhesive can be coated on the surface of the original aluminum foil to form a film. The film-forming technology will directly affect the heat sealing strength of the product. The more important parameters include coating speed, baking section temperature, coating roll shape, depth, line number and scraper position, Angle.
The rate of coating determines the drying time of the coating in the baking section. If the coating speed is too fast, the baking temperature is too high, will make the coating surface solvent volatilization too fast, resulting in the residual solvent within the film, film drying is not sufficient, hard to form a dry solid and firm adhesive layer, which will affect the heat sealing strength of the product, the product layer, and layer between the occurrence of adhesion.
The thickness and evenness of coating film are determined by the shape, depth, line number, position and Angle of the coating roller. If the selection or adjustment is not appropriate, the adhesive can not be evenly coated on the surface of the original aluminum foil resulting in uneven film formation, aluminum foil heat sealing film heat sealing effect will not be good, the strength will be affected.