Rubber ageing is that process by which natural rubber grades are exposed over a period of time to the attack of oxigen, ozone and ultraviolet light. Under these conditions cracks develop on the exposed surface. In bonded rubber products the rubber remains largely protected by the vulcanised-on metal part and antioxidants. Temperatures over 350 K (abount 80*C) accelerate ageing. To retard ageing, antiozonants are added to the rubber mixing process. The application of lacquer to exposed rubber surface is not of great significance. Spring of natural rubber should be compounded with waxes and thus always protected from the action of oil or petrol because these cause swelling, loosening of structure and reduced strength. Rubber product in systhetic rubber show greater resistance to the factors mentioned than those made from natural rubber.
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