What is the principle behind the shrinkage of heat shrinkable film after heating?

In our daily lives, we often come into contact with various packaging materials, among which heat shrink film occupies an important place in the packaging industry due to its unique properties. Are you curious about how this thin layer of film tightly adheres to the object after heating, achieving perfect shrinkage? Today, let's unveil the mysterious veil of shrinkage of heat shrink film after heating!

Firstly, we need to understand the basic characteristics of heat shrink film. Heat shrink film is a plastic film that can produce significant shrinkage at a specific temperature. This type of film remains stable at room temperature, but once heated to a certain temperature, it begins to rapidly shrink. So, how is this process implemented?

In fact, the principle of heat shrink film shrinkage is not complicated. This is mainly attributed to the special structure of the thin film material and the physical changes after heating. When making heat shrink film, the manufacturer will apply a special coating on its surface, which can quickly melt when heated, making the film surface soft and easy to shrink.

When we apply heat shrink film onto an object and heat it with a hot air gun or heat shrink machine, the coating on the surface of the film begins to melt and the film gradually becomes soft. At the same time, due to the tension inside the film, when the surface becomes soft, the film will quickly shrink under the action of tension and tightly adhere to the surface of the object.

This process is like a common rubber band. At room temperature, rubber bands maintain a certain length and shape; But when we heat it up, the rubber band becomes softer and rapidly shrinks under the action of internal tension. The shrinkage principle of heat shrink film is similar to this, except that its shrinkage process is faster and more uniform.

So, what are the practical applications of the principle of shrinkage of heat shrinkable film after heating? Firstly, it can be used for packaging various items such as food, beverages, cosmetics, etc. Through heat shrink packaging, items can be made more stable and safe during transportation and storage. Secondly, heat shrink film can also be used for labeling and promotion. By closely adhering to the surface of the object after shrinkage, we can print various patterns and textual information on the film to achieve the purpose of promotion and advertising.