What is the Curing Process?

Curing is the process by which an elastomer becomes cross linked. In a peroxide cured silicone, high temperatures break down the peroxide which creates the chemical which crosslinks the polymers in the chain.  Addition curing, platinum is added to the silicone as a catalyst. This causes the polymer chain to cross link with itself. Most of the silicone processed by Viking Extrusions is heat cured rubber (HCR) which uses the peroxide curing system to convert the silicone from compound to rubber.

The different curing systems give silicone rubber different properties. Below are the pros and cons of each method of curing silicone:

 

Platinum Cured Silicone

Pros

  • Platinum cured silicone is visually more transparent, making it suitable for applications where the end user needs to be able to see through the material.
  • Has a higher tensile and tear strength than peroxide cured silicone.
  • Does not require the use of talc in processing.
  • Considered to be the cleaner of the two types of silicone, used frequently in the food and pharmaceutical sectors.

Learn more about the solutions Viking Extrusions provide to the Food & Dairy and Pharmaceutical industries.

Cons

  • Platinum cured silicone is more expensive to produce than peroxide cured silicone.
  • Platinum cured silicone has a shorter shelf life. Once the catalyst is added to the compound the material will begin to cure. This means more scrapped material during production.
  • Silicone that is platinum cured is harder to process, it requires higher temperatures to cure.
  • Peroxide cured silicone has a long shelf life. Once mixed, it can be stored for long periods of time.
  • It is cheaper to produce, meaning competitive prices can be passed on.
  • It is easier to process and can be cured at lower temperatures.
  • Peroxide cured silicone can stick to its self in production and post curing, especially softer grades. Talc needs to be applied to the silicone to prevent unwanted crosslinking.
  • Peroxide cured silicone is not as transparent as platinum cured silicone. It is more translucent in appearance.

Peroxide Cured Silicone

Pros

  • Peroxide cured silicone has a long shelf life. Once mixed, it can be stored for long periods of time.
  • It is cheaper to produce, meaning competitive prices can be passed on.
  • It is easier to process and can be cured at lower temperatures.

Cons

  • Peroxide cured silicone can stick to its self in production and post curing, especially softer grades. Talc needs to be applied to the silicone to prevent unwanted crosslinking.
  • Peroxide cured silicone is not as transparent as platinum cured silicone. It is more translucent in appearance.

 

Viking Extrusions Supply both peroxide and platinum cured grades of silicone. If you are unsure about which grade you require for your application, please contact one of our experienced technical advisors who will be happy to assist you.