How to compound the inner PVC layer and outer aluminum foil of PVC composite aluminum foil tube?
Release Time : 2025-08-26
PVC composite aluminum foil tubes are widely used in ventilation, air conditioning, fresh air systems, and industrial smoke exhaust applications. Their performance advantages lie not only in their thermal insulation, flame retardancy, and flexibility, but also crucially in the tight integration of their multi-layered structure. The lamination process between the inner PVC layer and the outer aluminum foil is crucial for determining the hose's overall quality, durability, and performance. This lamination process is not simply a physical bonding process, but rather a series of carefully controlled material selection, surface treatment, and bonding techniques to achieve a secure bond between the two dissimilar materials, ensuring long-term resistance to delamination, splitting, and air leakage.
PVC composite aluminum foil tubes typically utilize a multi-layered design. The inner layer is a polyvinyl chloride (PVC) coating or film, which directly contacts the airflow, providing a smooth interior to reduce air resistance and possessing corrosion and mildew resistance. The outer layer, composed of aluminum foil, provides thermal insulation, heat reflection, UV protection, and mechanical protection. A spiral steel wire often serves as a support structure in the middle, ensuring the hose maintains a circular cross-section when bent or under negative pressure. The adhesive layer between these two critical materials connects them. The quality and uniformity of this adhesive layer directly determine the strength of the composite.
The lamination process is typically completed on a dedicated lamination line. First, the aluminum foil substrate is unwound and enters the processing area, where its surface undergoes necessary cleaning and activation. Because the aluminum foil's surface naturally has an oxide layer and is relatively smooth, direct application of adhesive may result in insufficient adhesion. Therefore, corona treatment or plasma treatment is often used to increase the foil's surface energy, making it easier for the adhesive to form a strong bond. The treated aluminum foil then enters the gluing unit, where a layer of hot-melt adhesive or reactive adhesive, specifically designed for bonding metals to polymers, is evenly applied. This adhesive offers excellent temperature and moisture resistance and long-term stability. It wets the PVC surface during the subsequent heating process and forms a strong chemical and physical bond.
Then, the PVC layer, softened by heat, is bonded to the glue-coated aluminum foil, with the pressure of the laminating rollers maintaining close contact between the two. Precise control of pressure and temperature is crucial. Too low a temperature prevents the adhesive from fully flowing and cross-linking, while too high a temperature may damage the material. During the hot pressing process, the adhesive penetrates the microporous structure of the PVC and forms a strong interfacial bond with the aluminum foil surface, resulting in a stable, integrated structure upon cooling. Some high-end products also undergo a post-lamination curing treatment to further cross-link the adhesive and enhance the final bond strength.
Tension control is also crucial throughout the lamination process. Aluminum foil and PVC have different elongation rates. Uneven tension can cause wrinkling, bubbles, or partial delamination. Therefore, the production line is equipped with a sophisticated tension adjustment system to ensure constant tension across all layers of material during simultaneous operation, resulting in a smooth, defect-free lamination.
The laminated material then undergoes cooling, shaping, and winding before being used for spiral wire winding and tube formation. Throughout the hose manufacturing process, the quality of the laminated layers is a key focus, with peel strength testing, temperature cycling tests, and long-term aging tests verifying their reliability in various environments.
In summary, the PVC composite aluminum foil tube's inner PVC layer and outer aluminum foil are firmly bonded through surface treatment, specialized adhesives, and a hot-pressing lamination process. This process, which combines materials science with precision manufacturing technology, ensures the hose maintains structural integrity and stable performance even under complex operating conditions, providing a solid foundation for the efficient and safe operation of ventilation systems.
PVC composite aluminum foil tubes typically utilize a multi-layered design. The inner layer is a polyvinyl chloride (PVC) coating or film, which directly contacts the airflow, providing a smooth interior to reduce air resistance and possessing corrosion and mildew resistance. The outer layer, composed of aluminum foil, provides thermal insulation, heat reflection, UV protection, and mechanical protection. A spiral steel wire often serves as a support structure in the middle, ensuring the hose maintains a circular cross-section when bent or under negative pressure. The adhesive layer between these two critical materials connects them. The quality and uniformity of this adhesive layer directly determine the strength of the composite.
The lamination process is typically completed on a dedicated lamination line. First, the aluminum foil substrate is unwound and enters the processing area, where its surface undergoes necessary cleaning and activation. Because the aluminum foil's surface naturally has an oxide layer and is relatively smooth, direct application of adhesive may result in insufficient adhesion. Therefore, corona treatment or plasma treatment is often used to increase the foil's surface energy, making it easier for the adhesive to form a strong bond. The treated aluminum foil then enters the gluing unit, where a layer of hot-melt adhesive or reactive adhesive, specifically designed for bonding metals to polymers, is evenly applied. This adhesive offers excellent temperature and moisture resistance and long-term stability. It wets the PVC surface during the subsequent heating process and forms a strong chemical and physical bond.
Then, the PVC layer, softened by heat, is bonded to the glue-coated aluminum foil, with the pressure of the laminating rollers maintaining close contact between the two. Precise control of pressure and temperature is crucial. Too low a temperature prevents the adhesive from fully flowing and cross-linking, while too high a temperature may damage the material. During the hot pressing process, the adhesive penetrates the microporous structure of the PVC and forms a strong interfacial bond with the aluminum foil surface, resulting in a stable, integrated structure upon cooling. Some high-end products also undergo a post-lamination curing treatment to further cross-link the adhesive and enhance the final bond strength.
Tension control is also crucial throughout the lamination process. Aluminum foil and PVC have different elongation rates. Uneven tension can cause wrinkling, bubbles, or partial delamination. Therefore, the production line is equipped with a sophisticated tension adjustment system to ensure constant tension across all layers of material during simultaneous operation, resulting in a smooth, defect-free lamination.
The laminated material then undergoes cooling, shaping, and winding before being used for spiral wire winding and tube formation. Throughout the hose manufacturing process, the quality of the laminated layers is a key focus, with peel strength testing, temperature cycling tests, and long-term aging tests verifying their reliability in various environments.
In summary, the PVC composite aluminum foil tube's inner PVC layer and outer aluminum foil are firmly bonded through surface treatment, specialized adhesives, and a hot-pressing lamination process. This process, which combines materials science with precision manufacturing technology, ensures the hose maintains structural integrity and stable performance even under complex operating conditions, providing a solid foundation for the efficient and safe operation of ventilation systems.