Composite film refers to a new packaging material composed of two or more films composited together. Composite film is the fastest growing packaging material in recent years. The reason for its rapid development is that a single variety of film can no longer meet the requirements of effectively protecting and beautifying products. The composite film can learn from each other's strengths and become a packaging material with excellent performance. Now there are hundreds of types of composite films, and the number of composite layers has grown from two layers to 10 layers.
　　 Composite film is made of plastic film as the base material, and then combined with other materials, such as paper, aluminum foil, cellophane, etc. Its main performance is as follows:
1. It has good heat-sealability. Many films, such as stretched polypropylene and polyester, have poor heat-sealability, but when combined with polyethylene with excellent heat-sealability, the heat-sealability can be greatly improved. Therefore, the composite film is mostly polymerized. Vinyl film is the inner layer;
　　2. Good air tightness, moisture resistance and heat resistance. The performance of cold resistance, fragrance retention, and UV transmission can effectively protect products, especially beneficial to the preservation of food;
　　3. Good product performance. The composite film has good transparency, glossiness, good printability, and is suitable for decoration. In addition, it has good rigidity, stiffness, and good shelf effect, which attracts customers;

　　4. It has excellent mechanical properties. It has good tensile strength, impact resistance, tear resistance, puncture resistance, bending resistance, pressure resistance, etc., plus good adaptability, which is convenient for mechanized operation;
　　5, lower. Under the premise of ensuring comprehensive performance, it can adopt the method of matching high and low price materials to manufacture composite films, so the total cost is lower.
　　6. ​​Lighter and easy to carry, it can replace some metal cans, glass bottles and other packaging containers. The weight is greatly reduced, and it is also convenient to transport and carry, and it is also convenient to open.