Palm oil-based zinc stearate synthesis process has been developed. Palm oil-based stearic acid and zinc oxide were used as material. The synthesis was performed using an oil-jacketed reactor with a capacity of 50 kg per batch. The reaction was occurring at 950C with atmospheric pressure and it took place about 10 minutes. The product characteristics was powder with a white appearance, 0.0 - 0.3 % fatty acid content, 0.2 - 1% moisture content, 118 – 1250C melting point and 0.5 - 1.1 g/cm3 specific gravity. The product of zinc stearate was also examined on an application of rubber component production process. Effects of using the zinc stearate to characteristics of the rubber component were tested. The characteristics included elongation, hardness and tensile strength of the rubber component. Application of 5 phr of zinc stearate on rubber component formulation showed that the rubber component processed using the zinc stearate has basic characteristic that meet the standard of rubber component of American Chemical Society (ACS) 1.

Vulcanization is an important step in the manufacture of solid tires in which the crosslinking process occurs. In vulcanization, the materials commonly used as activators and coactivators are ZnO and stearic acid, respectively. In this research, ZnO and stearic acid were replaced with zinc stearate to improve the characteristics of vulcanized rubber. Zinc stearate was applied in four formulas with a composition of 5 to 9 phr. A formula that is often used in the rubber industry was used as a comparison, and ZnO and stearic acid of 5 phr and 2.5 phr, respectively, were applied. The rubber compound for solid tire production was developed using an open mill at a compounding temperature of 45 °C ± 5 °C. The vulcanization process of developing the rubber compound into vulcanized rubber was carried out at 150 °C for 20 min. Rubber compound test results showed that the use of zinc stearate at a ratio of 8 phr accelerated the curing time (t90) between 58.3% and 69%, the scorch time (ts2) between 22.4% and 95.5%, and the torque delta (Ds) between 17.67 and 24.21 kg-cm. In addition, the vulcanized rubber mechanical properties test results for the compression set parameter increased between 28.6% and 57.1%. Scan results with SEM–EDS showed that using ZS could improve the homogeneous distribution of the material in the vulcanized matrix of solid tire rubber.