METHOD FOR STAILISING THE VISCOSITY OF NATURAL RUBBER DURING STORAGE AND THE ASSOCIATED IMPROVEMENT OF THE RESISTANCE TO THERMO-OXIDATION OF RUBBER PRODUCED FROM THE NATURAL COAGULATION OF LATEX AND IMPROVED NATURAL RUBBER RESULTING FROM THIS METHOD

摘要

The viscosity of natural rubber is stabilised during storage by the addition of thiosemicarbazide or its salts produced by the addition of an acid. The stabilising agent is preferably used in the form of an aqueous solution possibly emulsified in a mineral or vegetable oil, a ratio of thiosemicarbazide of 0.1 to 0.5% by weight with respect to the dry rubber being sufficient, and the stabilising agent is added to the latex or to the coagulated and granulated rubber before it is dried. The method provides a rubber having a decreased and stabilised viscosity which enables a saving in energy during mastication and mixing, a better rate of use of equipment, and savings in investment costs.