Freeze-Thaw Stabilitiy of Rubber Latices

Manufacturer: We are manufacturer of rubber products based on natural rubber latex (i.e., HA and LATZ from Thailand). Our problems are due to latex instability during winters caused by the freezing temperature. What can we do to solve this problem?

John Woon (Senior Latex Consultant): What you are experiencing is the effect of freezing and thawing of the latex due to the lack of proper temperature control during transporting and storage in winters. The symptoms are usually an increase in latex viscosity, drop in MST and the formation of coagulum. The mechanism of the destabilization involves the aggregation and coalescence of rubber particles forced by the ice crystals formed in the serum of the latex.

The immediate remedial action you could take is to dilute the latex slightly with alkali water followed by filtration and addition of stabilizers such as ammonium laurate.

For a long-term solution, you should request your suppliers of latex to offer you a freeze-thaw stable LA or LATZ which is usually produced with the addition of a freeze-thaw stabilizer such as sodium salicylate and ammonium laurate.