Material Composition of Liquid Self-Standing Spout Pouches

Liquid self-standing spout pouches are multi-layer composite flexible packaging materials specially designed for liquid storage. Unlike single-layer plastic bags that are prone to leakage and poor barrier performance, spout pouches adopt a layered composite structure, combining the advantages of different plastic materials to meet liquid packaging requirements such as leak-proof, pressure-resistant, fresh-keeping and safe contact. Their core materials are mainly composed of outer protective layers, middle barrier layers and inner heat-sealing layers. Different material collocations form transparent, matte, aluminum foil and high-temperature resistant models, adapting to various liquid packaging scenarios in daily life and industrial production.

The outer layer of ordinary transparent spout pouches mostly uses PET (polyester) material. PET has high transparency, strong stiffness, scratch resistance and stable chemical properties. It can keep the bag body flat and beautiful, effectively preventing surface wear during transportation and stacking, and is not easy to deform. For upgraded thickened pouches, PA (nylon) material is added to the outer layer. PA features excellent tensile strength and puncture resistance, which greatly enhances the durability of the pouch and avoids cracking caused by liquid gravity and external extrusion, making it suitable for large-capacity liquid packaging.

The innermost layer that directly contacts liquid is food-grade PE or CPP material, which is the key to safe sealing. PE material is soft, non-toxic and odorless, with excellent heat-sealing performance and low-temperature resistance. It is widely used in ordinary cold-drinking and daily chemical liquid spout pouches. In contrast, CPP (cast polypropylene) is a high-temperature resistant material, which can withstand high-temperature sterilization at 121°C. It is exclusively used for retort spout pouches for hot soup, cooked liquid food and high-temperature disinfection products, preventing melting and harmful substance precipitation.

For high-barrier light-proof spout pouches, an aluminum foil layer is added as the middle barrier layer. This composite structure of PET/AL/PE completely isolates oxygen, moisture and ultraviolet rays, effectively preventing liquid oxidation and deterioration. In addition, some environmentally friendly customized pouches use kraft paper composite materials for outer decoration while retaining food-grade plastic inner layers. In summary, the mainstream material combination of liquid spout pouches is PET/PE and PET/PA/CPP, with aluminum foil composite structures for high-barrier needs. This scientific layered design ensures safety, stability and durability for liquid packaging.

Google Academic Citation Formats

1. APA 7th Edition

Wang, Y. (2024). Material structure and barrier performance of liquid spout packaging pouches. Modern Packaging Engineering.

2. MLA 9th Edition

Wang, Yu. Material Structure and Barrier Performance of Liquid Spout Packaging Pouches, Modern Packaging Engineering, 2024.

3. IEEE Format

[1] Y. Wang, "Material structure and barrier performance of liquid spout packaging pouches," Modern Packaging Engineering, 2024.