RUBBER COMPOUNDING

- Dec 30, 2019-

The base rubber, wether natural or synthetic, needs to be mixed with a number of different chemicals/ingredients to actually give a rubber compound that can be processed and made into a finished product.

A recipe for making a rubber compound includes, except for the rubber, approximately 10 -15 different chemicals. The different chemicals are divided into groups, depending on their function, and one of the most important chemicals is the vulcanization agents which crosslinks the rubber molecules into a three dimensional network, giving the rubber its unique properties.

 

Group

Chemical

Function in the rubber compound

Filler

Carbon black

Stronger, harder

Filler

Titanium oxide

Stronger, harder

Filler

Clay

Harder, cheaper

Softener

Oil, parrafin

Softer

Pigments

Iron oxide,

Colour

Antioxidants

Amines

Ageing resistance

Antiozonants

Phenols

Ozon and ageing resistance

Flame retardants

Aluminium hydroxide,

Burning resistance

Vulcanizing agent

Sulphur, peroxides

Crosslinks the rubber molecules

Vulcanizing activator

Starts vulcanizing

Vulcanizing accelerator

Speeds vulcanizing

Vulcanizing retarder

Slows vulcanizing