Problems often encountered when using PVC heat shrinkable film

PVC shrink film was used in industrial packaging from the beginning of industrial production, and then it was used in food packaging, for example, PVDC casing film was used in sausage packaging. PVC shrink film uses the energy that the film has been stretched longitudinally or transversely in a high elastic state to be stored in the film, and uses the memory effect of thermoplastics on the shape before biaxial or unidirectional stretching to restore the shape before stretching when it meets heat again to achieve the packaging purpose. Shrinkage film is mainly used in the sales and transportation of products, which is used to stabilize, cover and protect products, while plastic wrap film is mainly used to keep food fresh, which is the fundamental difference between the two.

Principle of PVC heat-shrinkable packaging film: In the production process, when the film is stretched at a temperature above its softening point and below its melting point, the molecules are aligned; when the film is cooled sharply, the molecules are "frozen"; when the film is reheated to the stretched temperature, stress relaxation occurs, that is, the oriented molecules are de-oriented, which causes the film to shrink. When the orientation degree is high, the thermal shrinkage rate is high, while the orientation degree is low.

Four common problems and solutions when using PVC heat shrinkable film:

1. The shrink bag of the wrapping package is too big, so you can make the shrink bag smaller.

2. The speed of shrinking the conveyor belt of the packaging machine is too fast, so you can lower the speed of the conveyor belt.

3. The circulating wind power of shrink packaging machine is too low, so it can be turned down.

4. The temperature of the shrink packaging machine is too low, so the temperature of the packaging machine can be increased.

Principle of PVC heat shrinkable film Production The stable state of polymer chain tends to curl. When the polymer is in a high elastic state when heated and melted, the orientation of the polymer chain is stretched and straightened under the action of external force, and the orientation state of the polymer chain is frozen after rapid cooling reaches the glass transition temperature. When the temperature rises again, the polymer chain tends to be stable and curls, which is macroscopically manifested as contraction. According to its shrinkage principle, there is no chemical change, so it is called "physical reducibility". Using the above principle, the PVC heat shrinkable film made by blow molding is made after twice inflation and rapid cooling. PVC heat shrinkable film is a new packaging material popular all over the world at present. It has good transparency, good toughness, no fear of impact, no corrosion and low water vapor transmission. There is also an ideal shrinkage rate. When the film is subjected to temperature, it automatically shrinks and tightly wraps the goods, thus protecting the goods, and also playing the roles of rust prevention, pollution prevention, pre-injury prevention and theft prevention. Commodity storage stability, simple packaging technology and equipment, easy to realize automatic shrink packaging. PVC heat shrinkable film is used for the sales and transportation of various products, and its main function is to stabilize, cover and protect the products. Shrinkage film should have good puncture resistance, good shrinkage and corresponding shrinkage stress. In the process of shrinkage, the film cannot produce holes. Because PVC heat shrinkable film is often used outdoors, it is necessary to add UV-resistant agent.

Heat shrinkable film can be used in many industries, and can be used in the outer packaging of printed matter, hardware and plastic products, telephones, electronic appliances and so on. Now we will learn about this knowledge.

We know that because goods are all in different shapes, in order to ensure that products can protect goods, we have changed the old-fashioned mode of products, and used new technology to manufacture products that can be used in any environment. In the combined (bundled) packaging of irregular-shaped goods or commodities in heat shrinkable film, it can not only achieve the functions of dust prevention, anti-touch and transparent display, but also increase the attractiveness of products, and can also be used to replace all kinds of cartons. PE shrink film not only saves packaging costs, but also conforms to packaging.

In order to determine the service life of the product, it needs to be placed in a suitable environment, which plays a good role in prolonging the service life of the product and saves us costs.