Platinum-Cured vs Peroxide-Cured Silicone: Which One Do You Need?

Platinum-cured silicone is cleaner, odorless, and required for food and medical parts.

Peroxide-cured silicone costs less and works well for general industrial seals.

The right choice depends on your application — not on which one is “better.”

What Does “Cured” Mean?

Silicone rubber starts as a soft gum. To become a finished part, it must be cured (also called vulcanized). Curing links the rubber chains together and gives the part its final strength and shape.

There are two common curing systems:

The base silicone is often the same. The curing system is what changes the final properties.

Peroxide-Cured Silicone

Peroxide curing uses organic peroxides to start the cross-linking reaction.

Best for: general industrial O-rings, gaskets, pads, and parts that do not touch food, water, or the human body.

Platinum-Cured Silicone

Platinum curing uses a platinum catalyst. The reaction is clean — it produces no by-products.

Pros:

• No by-products, no odor
• Higher purity, lower extractables
• Better clarity (more transparent)
• Meets FDA 21 CFR 177.2600, USP Class VI, and EU 1935/2004
• Better yellowing resistance

Cons:

• Slightly higher material cost
• The catalyst is sensitive — contamination during production can ruin the cure

Best for: food equipment seals, drinking water parts, medical devices, baby products, and anything with a purity requirement.

Side-by-Side Comparison

Tips from ZSR: You cannot tell the curing system just by looking at a finished part. Always ask your supplier for the cure type in writing — and the FDA or USP certificate if your part needs it.

Does Curing System Affect Sealing Performance?

For most static seals, no. Both systems give similar:

The difference is about purity and compliance, not mechanical performance.

How to Choose: A Simple Rule

Ask one question: Does the part touch food, drinking water, or the human body?

• Yes → choose platinum-cured
• No → peroxide-cured is usually the smarter buy

Advice from ZSR: Some buyers specify platinum-cured for every part “just to be safe.” That is fine — but if your parts are industrial-only, peroxide-cured silicone saves real money at volume. Tell us your application, and we will recommend the honest option.

What About LSR (Liquid Silicone Rubber)?

LSR parts are almost always platinum-cured. If your parts are small, complex, or high-volume, LSR injection molding with platinum cure gives you the best purity and consistency.

Read more: HTV vs LSR Silicone: Which Molding Process Fits Your Parts?

FAQ

Q: Is peroxide-cured silicone safe? 

A: Yes, for industrial use. With proper post-curing, it is stable and safe. It just does not meet food or medical purity standards.

Q: Can platinum-cured silicone fail FDA testing?

A: The curing system alone is not enough. The full compound — base rubber, fillers, pigments — must all be compliant. Buy from a manufacturer who controls the recipe.

Q: Is platinum-cured silicone more expensive in the final part?

A: Material cost is higher, but platinum-cured parts often skip the long post-cure oven step. For many parts, the final price difference is small.

Q: Can you make colored platinum-cured parts?

A: Yes. We use FDA-compliant pigments for food-grade colored parts.

Q: How do I switch my existing part from peroxide to platinum cure?

A: Send us the drawing or sample. In most cases we can use the same mold and only change the material. We will confirm after checking your part design.

Related reading: What Is VMQ Silicone Rubber? | HTV vs LSR Silicone