Temperature of Latex and Its Effects on Latex Stability and Skinning Tendency

Manufacturer: We always encounter some problems with latex stability, especially skinning during summers. Why?

John Woon (Senior Latex Consultant): This question had been raised before (see my earlier post below). When the ambient temperature increases during summers, the temperature of the latex invariably also increases (unless there is a good cooling system).

When this happens, the kinetic energy of the rubber particles is increased and as a result, the rubber particles tend to move at a very much faster rate. This results in the increase in both the frequency and violence of the collision of rubber particles with each other. The end result is coalescing and coagulation. 

Also, at elevated temperatures, the latex surface tends to lose more moisture and ammonia, resulting in skinning. 

Natural rubber latex is therefore best stored at temperature ranging from 15°C to 30°C. Wherever necessary, water chiller should be used, especially in the latex dip tank.

You can also overcome the skinning problem by adding 0.1 to 0.3 phr of KOH to the latex with the addition of stabilizers such as ammonium laurate to further stabilise the latex.