The word “composite” in the flex industry actually means “lamination”. That is to say, films of different properties are glued together in a certain way and sealed to protect the contents. The laminated structure of flexible packaging can be divided into many types according to different combinations, so we cannot use only one system to describe different structures. However, the structure of traditional flexible packaging is often distinguished by outer layer, middle layer, adhesive layer, and inner layer. A typical three-layer composite structure is shown in the figure：
1. Outer material
The material used in the outer layer usually has good mechanical strength, heat resistance, good printing performance, good optical performance and other properties. At present, the most commonly used outer materials are PET, NY, BOPP, PAPER, etc.
2. Middle layer material
The middle layer material is generally used to enhance the barrier properties, shading properties, fragrance retention properties, strength and other properties of the layered structure. Now the most commonly used materials for the middle layer are AL, VMCPP, VMPET, PET, NY, KBOPP, KPET, KNOY, etc.
3. Inner material
The most critical and important function of the inner layer material is sealing performance, followed by pressure resistance, drop performance, acid and alkali resistance and airtight performance. The most commonly used inner layer materials are CPP, PE, PLA and their modified materials.
The material will be customized according to different products. There are two-layer material structure, three-layer material structure, and four-layer material structure can be selected.
For example: coffee bags: commonly used materials are dumb OPP/VMPET/PE and PAPER/VMPET/PE, PAPER/PLA etc.;
Liquid spout bag: commonly used materials are PET/NY/PE and PET/AL/NY/PE, etc.
If you don’t know what material to use for the packaging bag you need, please tell me, we will recommend the most suitable material structure to you, welcome to inquire! !
Post time: Dec-08-2022