What mainly determines the transparency of cast PVC shrink film?

The transparency of cast PVC shrink film is mainly determined by the following key factors:

Raw material purity: The purity of PVC resin is an important factor affecting its transparency. High-purity PVC resin contains fewer impurities and opaque particles, allowing the production of shrink films with higher transparency. If the raw materials contain too many impurities or additives, the transparency of the shrink film may be reduced.

Production process: Parameters such as temperature, pressure, speed and cooling conditions in the casting process have a significant impact on the transparency of PVC shrink film. Reasonable process parameters can ensure that PVC resin flows evenly in the molten state, reduce internal stress and the formation of bubbles, thereby improving transparency.

Use of additives: During the production process, in order to improve the performance of PVC shrink film, some auxiliaries and additives may be added, such as plasticizers, stabilizers, etc. The types and amounts of these additives may affect the transparency of the shrink film. Excessive amounts of additives or the wrong type of additives can cause the shrink film to become cloudy or opaque.

Film thickness and surface treatment: Film thickness is also one of the factors affecting transparency. Thinner films generally have higher transparency because light passes through thin materials more easily. In addition, surface treatment of the film, such as polishing or coating, may also have some impact on transparency.

Storage and use environment: During storage and use, PVC shrink film may be affected by environmental factors such as temperature, humidity, and light, resulting in reduced transparency. For example, prolonged exposure to sunlight can cause PVC materials to age, affecting their transparency.