I. Core Characteristics of Aluminum-plastic composite packaging bags

(I) Excellent Barrier Performance

The significant advantage of aluminum-plastic composite packaging bags lies in their barrier performance, primarily achieved through the combined action of the aluminum foil layer and the plastic layer in their structure. The aluminum foil layer possesses extremely high barrier properties, effectively blocking the influence of external factors such as oxygen, water vapor, ultraviolet radiation, and odors on the product inside the bag. Oxygen is a major factor leading to food oxidation and spoilage, and to reduced efficacy of pharmaceutical products. The aluminum foil layer can control oxygen permeability to an extremely low level, typically below 0.1 cc/(m²・24h・atm), ensuring the product inside the bag remains in a low-oxygen environment for an extended period, significantly extending its shelf life.

Water vapor intrusion can cause the product to become damp, affecting its quality and stability. For example, damp electronic components may experience short circuits and performance degradation; damp food is prone to mold and clumping. The aluminum foil layer in aluminum-plastic composite packaging bags effectively blocks water vapor penetration, with a water vapor transmission rate typically less than 1 g/(m²・24h), ensuring a dry environment inside the bag and protecting the product's condition during storage and transportation. Furthermore, ultraviolet radiation can damage some of the product's active ingredients, such as vitamins in food and active ingredients in pharmaceuticals; the aluminum foil layer completely blocks UV penetration, preventing damage. Simultaneously, the aluminum foil layer also prevents external odors from entering the bag and prevents the spread of odors from the product inside, maintaining the product's original flavor and quality.

The addition of a plastic layer further optimizes the barrier system. The outer plastic layer (such as PET or PA) has good puncture resistance and dimensional stability, protecting the aluminum foil layer from damage during transportation and handling, preventing a decrease in barrier performance due to foil breakage. The inner plastic layer (such as PE) has excellent heat-sealing properties, ensuring a tight seal, reducing air residue, and further enhancing the barrier effect. This aluminum-plastic combined structure allows aluminum-plastic composite packaging bags to provide comprehensive barrier protection for various types of products.

(II) Excellent Physical and Mechanical Properties

Aluminum-plastic composite packaging bags exhibit excellent physical and mechanical properties, combining flexibility with a certain level of strength to adapt to various complex usage scenarios. The plastic layer provides the packaging bag with good flexibility and extensibility, allowing it to be fitted to the shape of the product. Whether it's irregularly shaped meat, nuts, or liquids and powders, it can tightly wrap them, reducing packaging space waste and facilitating product storage and transportation.

In terms of strength, aluminum-plastic composite packaging bags, through the synergistic effect of their multi-layered structure, possess high tensile strength and impact resistance. Longitudinal tensile strength is typically ≥180MPa, and transverse tensile strength is ≥150MPa, capable of withstanding certain tensile and compressive forces, and is less prone to tearing or damage during loading, unloading, and handling. Experimental data shows that when dropped from a height of 1.2 meters, the integrity rate of aluminum-plastic composite packaging bags can reach over 90%, far exceeding that of some single-layer plastic packaging bags.

Furthermore, aluminum-plastic composite packaging bags also have good temperature resistance, adapting to a temperature range of -40℃ to 121℃. In low-temperature environments, the bags are less prone to cracking, making them suitable for long-term storage of frozen foods (such as frozen dumplings and seafood). In medium- and high-temperature environments, some high-temperature resistant aluminum-plastic composite packaging bags (such as PET/AL/PE structures) can withstand sterilization treatment at 121℃, meeting the packaging needs of canned goods, cooked foods, and other products requiring heat sterilization. Simultaneously, their puncture resistance is also outstanding; the inner PE or PA layer effectively resists punctures from sharp objects, preventing leakage of contents or intrusion of external contaminants, making them suitable for packaging products with sharp edges, such as nuts with shells and metal parts.

(III) Excellent Printing and Appearance Performance

Aluminum-plastic composite packaging bags have significant advantages in appearance and printability, enhancing brand image and market competitiveness. The aluminum foil layer itself has a unique metallic luster, presenting a silver-white or specially treated multi-colored effect. Combined with transparent or semi-transparent plastic layers, it can create diverse visual styles. For example, transparent PET/AL/PE structure packaging bags achieve a "partially transparent display + partially metallic texture" effect. Consumers can clearly see the shape of the food inside, while the metallic sheen enhances the product's premium feel. Opaque AL/PE structures are suitable for products requiring light protection, such as vitamin tablets and photosensitive cosmetics, and their surface allows for exquisite printing.

In terms of printing performance, the surface of aluminum-plastic composite packaging bags undergoes special treatment, ensuring sufficient surface tension to support various inks. Printed patterns exhibit strong adhesion and are less prone to fading or scratching. Gravure printing technology enables high-definition, multi-color printing, clearly displaying complex product designs, brand logos, and detailed product descriptions and ingredient lists. The vibrant colors and rich detail of the printed patterns effectively attract consumer attention, helping businesses better showcase their brand image and product features. Furthermore, the high flatness of aluminum-plastic composite packaging bags reduces the likelihood of wrinkles or misalignment during printing, further ensuring the product's aesthetic appeal.