News & InsightsIn-Depth
2026年5月20日
How to determine the thickness of each layer in flexible packaging?
The theoretical method for determining the thickness of flexible packaging composite materials is as follows:
Considering both packaging costs and performance requirements, the thickness selection of each layer in composite flexible packaging materials requires careful deliberation. Generally, the heat-sealing layer can be determined through market standardization, the strength support layer is typically based on the weight of the packaged product, and the thickness of functional materials is usually determined by the product's shelf life.
The theoretical method for determining the thickness of flexible packaging composite materials is as follows:
- Based on the maximum allowable water absorption or maximum allowable dehydration of the packaged product, this method is mainly suitable for the moisture-proof packaging design of the product, and the key is to calculate the moisture permeability coefficient of the flexible packaging composite material.
- Based on the maximum allowable oxygen absorption of the packaged product, this method is mainly suitable for barrier packaging of products that are highly sensitive to oxygen. The key is to calculate the oxygen permeability coefficient of the flexible packaging composite material.
- Based on the maximum allowable number of microorganisms per unit volume or unit surface area, this method is mainly suitable for anti mold packaging of products that are highly sensitive to microorganisms. The key is to determine the types of microorganisms in the product and their reproductive and growth patterns.
- Based on the maximum allowable carbon dioxide or oxygen permeability of the packaging container, this method is mainly aimed at inflatable insurance packaging of products. Products with declared activity require both oxygen insurance or maintaining bright colors, as well as high concentrations of carbon dioxide to inhibit microbial growth and reproduction. The key is to calculate the oxygen and carbon dioxide permeability coefficients of the flexible packaging composite material.
When packaging products, sometimes it is necessary to achieve both moisture-proof packaging and oxygen blocking or mold proof packaging. Therefore, the thickness of composite packaging materials is generally determined based on the main packaging purpose and shelf life of the product packaging, and then the theoretical shelf life of the designed packaging is estimated based on the thickness of the material and another packaging purpose to verify the rationality of the design packaging.