Why do rubber parts turn white

The reason why the appearance of rubber parts is white is the spray!

Reason analysis:
1 Excessive fit
The solubility of various auxiliaries in rubber is also different, and the smaller the solubility of auxiliaries in rubber, the more likely it is to overcooperate and cause frost spraying. The spray caused by excessive mixing often brings other groups to spray together, although these sprays are far from saturated in the rubber.

2 Temperature change
Additives usually in the rubber solubility will change with the change of temperature, in general, in this case, when the temperature is high, the solubility will also become larger, and when the temperature is reduced, the solubility will gradually decrease. Since rubber products are generally used at room temperature, once the outside temperature is lower than room temperature, the content of some additives in the formula is close to its solubility, resulting in spray. For example, the rubber shoes produced in summer pass the factory inspection, and are stored in winter only to find that the frost is sprayed.

3 under-sulfur
The solubility of additives in rubber is affected by vulcanization. Taking NR as an example, under the condition of positive vulcanization, the cross-linking density is the highest, the free sulfur gradually decreases, and the chance of sulfur spraying is also gradually reduced. The chance of other additives shuttling through the three-dimensional network is also reduced a lot, so the chance of frost spraying is also gradually reduced. On the contrary, in the less sulfur state, the cross-linking density of the network will be relatively small, and the chance of spraying will be correspondingly increased.”