What are the main steps in the production process of polyester/aluminum/polyethylene composite film?
Publish Time: 2025-02-13
Polyester/aluminum/polyethylene composite film, referred to as PET/AL/PE composite film, is a high-performance packaging material widely used in food, medicine, daily chemical products and other fields. Its production process mainly includes the following key steps:
1. Raw material preparation and pretreatment
The first step in producing PET/AL/PE composite film is the preparation and pretreatment of raw materials. The polyester (PET) layer provides strength and barrier properties, the aluminum foil (AL) layer provides excellent barrier properties and light-shielding properties, and the polyethylene (PE) layer provides heat sealing properties and certain flexibility. These raw materials need to be carefully selected to ensure that there are no impurities and the moisture is controlled within a certain range to ensure the stability of subsequent processing and the quality of the composite film.
2. Film extrusion and stretching
The pretreated polyester raw material is fed into the extruder, and after melting and plasticization, it is extruded through the die to form a continuous film. Subsequently, the film is stretched longitudinally and transversely to improve its mechanical strength and dimensional stability. During the stretching process, the stretching ratio and temperature need to be precisely controlled to avoid film rupture or performance degradation.
3. Vacuum coating of aluminum foil
Coating a layer of aluminum foil on polyester film is a key link in the production of PET/AL/PE composite film. Usually, vacuum aluminum coating is used, that is, metal aluminum is melted and evaporated at high temperature under high vacuum, so that the aluminum vapor is precipitated and accumulated on the surface of the polyester film to form an extremely thin metal aluminum layer. This step requires strict control of vacuum degree, evaporation temperature and aluminum coating speed to ensure the uniformity and adhesion of the aluminum foil layer.
4. Extrusion and lamination of polyethylene layer
The aluminum-plated polyester film is compounded with polyethylene melt. After the polyethylene melt is extruded through the extruder, it is tightly combined with the aluminum-plated polyester film on the laminating machine through hot pressing or adhesive. During the laminating process, the laminating temperature, pressure and speed need to be controlled to ensure the good bonding of the two layers of materials and the flatness of the composite film.
5. Post-processing and inspection
After cooling and curing, the composite film is subjected to post-processing operations such as winding and slitting. At the same time, the composite film needs to be strictly inspected, including indicators such as appearance quality, barrier properties, and mechanical strength, to ensure that the product quality meets customer requirements and relevant standards.
In summary, the production process of polyester/aluminum/polyethylene composite film is a complex and delicate process, which requires strict control of parameters and quality in each link to ensure that the performance and quality of the final product meet market demand.
