In any molded rubber product, the three major influences of part quality that we control are the mold, the process and the rubber formulation. By far the most influential is the latter. In plastics, designers can use material suppliers’ specification data to determine what material will work best in their application, but in rubber, that information is not readily available. The reason is the plastic molder purchases their materials in a ready to process form and the resulting physical and environmental resistance properties are controlled by that supplier. In contrast, the rubber molder purchases ingredients from many suppliers and mixes them to form the material that is processed in the mold, therefore, each molder controls the material’s and resulting end product’s properties.
Compounding can be broken into five main systems as follows :
1. Elastomer System
One or more elastomers for characteristics
Elastomer for improved processing
2. Filler System
Reinforcing filler
Semi and non-reinforcing fillers
Plasticizers
3. Protectants
Antioxidents
Antiozonants
Inhibitors/promoters
4. Process Aids
Mixing Aids
Molding Aids
5. Cure System
Vulcanizing Agents
Activators
Accelerators
Scorch Retarders
The following is a useful procedure to guide compound development |
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RUBBER COMPOUNDS | Basic Rubber Compounds |