Physical and mechanical properties include tensile strength and elongation at break. It reflects the ability of the product to be stretched during use. If this is not qualified, food packaging bags are prone to break and damage during use.

Internal requirements: The inherent requirements of food packaging refer to the technical requirements of ensuring quality and quantity of food in its packaging through packaging.

Strength requirements: refers to the packaging can protect the packaged food in storage, stacking, transportation, handling process against various external destructive forces, such as pressure, impact and vibration force. There are many factors related to the strength of food packaging, such as transportation mode (such as automobile, aircraft), stacking form (such as multi-layer stacking, cross stacking) and environment (such as climate, sanitary environment).

Barrier requirements: Barrier is one of the important properties in food packaging. Many foods are stored and packaged. Because of poor barrier, the flavor and quality of food change, which ultimately affects the quality of food. Barrier requirements are determined by the characteristics of food itself, which are characterized by external barrier, internal barrier or selective barrier, etc. The barriers are air, water, grease, light, microorganisms and so on.

Food packaging bags with unqualified quality are very harmful to both food packaging manufacturers and ordinary consumers. In order to be responsible for the vast number of consumers, and also for the development and progress of enterprises themselves, food packaging manufacturers should strictly control the quality of food packaging bags in the production process and improve the quality of food packaging bags.

It can be predicted that in the next few years in China, the packaging industry will develop rapidly, among which petroleum and other chemical products are indispensable materials in the production of packaging bags. In the future, the use of plastic products will become more and more frequent. It will gradually reduce people's use of glass products. Sometimes plastic products will replace metal products.

Further development of aseptic packaging will reduce the need for refrigeration equipment. Some consumers feel that metal canned food is a high-grade product, and aseptic packaging is mostly cartons and low-cost products. In fact, this is a misunderstanding. Packaging should take twice the effort. As long as food can be well preserved, the cheaper it is, the better it is.