Elastomer Compounding for DuPont Elastomers
DuPont™ Viton®, DuPont™ Vamac® and DuPont™ Neoprene elastomers are hardly ever made into finished parts by themselves. They are mixed with other ingredients to make compounds that have properties that can meet a variety of end use requirements. A typical elastomer compounding of Neoprene (and finished part) contains about 30 to 50% Neoprene by weight. A typical Viton® compound (and finished part) contains about 75% Viton® by weight.
Several different ingredients are used in compounds based on Viton®, Vamac® and Neoprene to allow them to meet the processing requirements and the end use requirements. Some compounds may only have three or four ingredients in a formulation while other compounds may have more than ten ingredients. Some of the key ingredients include
- Carbon Black to provide improved physical properties such as higher tensile strength while not taking away from the rubber like properties. Mineral fillers like silica and calcium carbonate can also be used.
- A curative package that allows compounds to cure up to the desired finished properties. The cure package is typically designed to not activate at low temperatures but cure quickly at higher temperatures. If the cure package is not designed properly there can be scorch issues (cures too quickly) or poor cured properties (high compression set).
- Plasticizers to improve low temperature properties and to improve the ease of processing the compounds. They also allow more filler to be added which can lower the compound cost.
- Stabilizer packages that protect the compound during heat aging or against exposure to ozone or other end use environmental factors.
- Process aids that significantly improve the processing without hurting the end use properties.
DuPont has developed expertise in designing compounds based on Viton®, Vamac® or Neoprene. Starting point formulations can be designed so as to meet
- Processing Needs
- Shore A Hardness
- Tensile Strength
- Fluid Aging Requirements (gasoline, engine oil, etc)
- Heat Aging Requirements (70 hrs at 100C, 1 wk at 230C)
- Low Temperature properties
- Compression Set
Please contact DuPont for help in designing compounds to meet your end use requirements.