Rubber materials are blends of additives. Each rubber material is unique. In some cases the materials from different suppliers are very similar, and in other cases they are not. The most important ingredient is the POLYMER, which may be from 15 to 70% (usually around 50%) by weight of the rubber material.

A typical formulation may look like:

POLYMER 50%
Fillers 40%
Softener 5%
Activators 2%
Curative 1%
Accelerators 1%
Antioxidant 1%
All additives (type and concentration) affect the properties of the rubber material, thus influencing the final properties of the end product.

A rubber material developed for a certain product is seldom useful in other applications. For technically more advanced products there are always specially developed materials to fulfill the specific demand.

The standard rubber polymer for weather resistance or water/steam resistance is EPDM (Ethylene-Propylene Rubber), while Nitrile rubber (NBR) is the standard rubber polymer for oil resistance.

Some other examples of polymer types are:

Chlorinated Polyethylene (CM)
Acrylic Rubber (ACM)
Polysulphide Rubber (T)
Polyurethane Rubber (AU<EU)
Polynorbornene (PNR)
Polypropylene (PO)
Fluorocarbon Rubber (FKM)
Perfluoroelastomer (FFKM)
and a lot more...
The curing/vulcanization of rubber is a chemical reaction, where the curatives will alter the polymer being a high viscous liquid to be a solid, thus giving the material its elasticity.