Why is the plastic enclosure sticky?

Sticky surface of plastic enclosure is a manifestation of plastic aging. Plastic aging refers to the damage of its chemical structure, the deterioration of physical properties, the decrease of mechanical properties, and the fact that it becomes hard, brittle, or soft due to long-term exposure to ambient environmental conditions such as air, light, and heat during use.

There are two main manifestations of plastic aging:
The first is that plastic products become hard and cracks appear.
Second, plastic products become soft and sticky on the surface.

The way plastic ages is mainly determined by the type of plastic and the environment in which it is used.