The phenomenon of PVC oiling
In short, PVC oiling is the phenomenon that the plasticizer (mainly phthalates) in PVC material gradually precipitates to the surface of the material during use. The main function of plasticizer is to soften PVC, enhance its plasticity, and facilitate molding and processing. However, with the passage of time and the natural aging of plastics, plasticizers will gradually migrate from the inside of PVC to the surface, forming a colorless, transparent, viscous oily substance. Especially in high temperature environments, this process will be significantly accelerated. If PVC products are in a sealed environment for a long time, plasticizers have nowhere to dissipate, and the oiling phenomenon will be more obvious.

PVC products with a soft feel often contain more plasticizers, so they are more likely to oil out. Although environmentally friendly PVC uses more environmentally friendly DOTP (dioctyl ester) as a plasticizer, DOTP has a more obvious tendency to oil out compared to traditional plasticizers.

Reasons for PVC oiling
The reasons for PVC oiling are complex and varied, mainly including the following aspects:

Raw material problems: The molecular structure of PVC materials that have been recycled many times may have been destroyed, making it easier for plasticizers to precipitate.

Improper selection or excessive use of plasticizers: The type and amount of plasticizers directly affect the oiling of PVC. Improper selection or excessive use of plasticizers will aggravate the oiling phenomenon.

Improper selection or excessive use of heat stabilizers: Heat stabilizers are used to prevent PVC from decomposing during high-temperature processing. However, improper selection or excessive use of heat stabilizers may also affect the oiling performance of PVC.

Improper processing technology: Poor plasticization of PVC is also an important cause of oiling. Improper control of parameters such as temperature, pressure, and time during processing may affect the plasticization degree and oiling performance of PVC.

Solution to PVC oiling
For the problem of PVC oiling, the following aspects can be used to solve it:

Solve it from the raw materials and production process: Select high-quality PVC raw materials and avoid using recycled materials for many times. At the same time, optimize the production process to ensure good plasticization of PVC and reduce the precipitation of plasticizers. In addition, you can also try to use new environmentally friendly plasticizers and heat stabilizers to reduce the tendency of oil discharge.

Scrubbing treatment: Taking advantage of the characteristics of plasticizers that are difficult to dissolve in water but easily soluble in a variety of organic solvents, and easily soluble in a variety of organic solvents such as methanol, ethanol, and ether, you can use the scrubbing method to remove oil stains on the surface of PVC.