What is an eight-side seal bag?
An eight-side seal bag is a type of packaging formed through a specialized heat-sealing process; it derives its name from the eight sealing edges present when fully expanded (two at the top, two at the bottom, and two on each side). Compared to traditional three-side seal or back-seal bags, it features a more stable, three-dimensional structure that maximizes space utilization. It is ideal for applications requiring pressure resistance or the showcasing of a product's 3D profile-such as in the packaging of pet food and nut snacks.
Key features of eight-side seal bags
● Superior sealing performance: The eight-side seal structure is achieved through multi-layer heat sealing, offering better airtightness than standard packaging bags. In food packaging applications, for instance, the oxygen transmission rate can be kept below 20 cm³/m²·24h (referencing standard GB/T 1037-2021, "Test methods for gas permeability of plastic film"), significantly extending shelf life.
● High load-bearing capacity: Thanks to its multi-sided support structure, the bag can support weights of 5–10 kg (depending on material thickness), making it suitable for heavy items like rice and cat litter.
● Excellent printability: The flat, eight-sided structure allows for a complete and uninterrupted display of graphics; gravure printing is commonly used, achieving resolutions of up to 175 lines per inch.