Rubber blooming refers to the phenomenon that liquid or solid compounding agents migrate from the inside of the rubber to the outside surface of the rubber. So why does rubber blooming occur?
Causes of blooming
The reason why rubber blooming occurs is that the energy of the compounding agents in the rubber has reached an oversaturated state. Therefore, some of the excess compounding agents seep out to the surface of the rubber. It ends only when the concentration of the compounding agents is no longer in an oversaturated state. In this process, the compounding agents migrate from the inside of the rubber to the outside. Therefore, the compounding agents on the outer layer of the rubber seep out first. Then they seep out from the inner layer of the rubber to the outer layer.
Three forms of blooming
Generally speaking, blooming can be divided into three categories, namely powder spraying, wax spraying and oil spraying. These three forms of blooming do not necessarily exist in a single form. They may appear in two or three forms at the same time. Powder spraying is the powdery compounding agents in the rubber, such as vulcanizers, accelerators, anti-aging agents, etc., which precipitate on the surface of the rubber to form a layer of powder. Wax spraying refers to the precipitation of some waxy substances such as paraffin wax and ozokerite, forming a wax film on the rubber surface. Oil spraying is similar to the above two methods. However, it precipitates some liquid compounding agents such as softeners, tackifiers, plasticizers, etc. It will form a layer of oil on the rubber surface.