In addition to our Light Tan Natural Rubber, our Black Natural Rubber offering exhibits extremely good resiliency and abrasion resistance. It has good tear strength and is resistant to water, most salts and mild acids. Oct 15, 2018 · INTRODUCTION Rubber, elastic substance obtained from the exudations of certain tropical plants (natural rubber) or derived from petroleum and natural gas (synthetic rubber). Because of its elasticity, resilience, and toughness, rubber is the basic constituent of the tires used in automotive vehicles, aircraft, and bicycles. 4. A process for producing a natural rubber for a pressure-sensitive adhesive, which comprises decreasing a molecular weight of an unmasticated natural rubber by the action of a peptizing agent while dissolving the unmasticated natural rubber in an organic solvent, and a natural rubber-based pressure-sensitive adhesive composition comprising a natural rubber having a weigh average molecular ... Natural rubber contains a viscosity stabilizer for the natural rubber, and the viscosity stabilizer includes a hydrazide compound of the following general formula, R--CONHNH.sub.2 wherein R is an alkyl group having 1 to 5 carbon atoms or a cycloalkyl group having 3 to 5 carbon atoms.