Understanding the differences between platinum cured and tin cured silicone will help you choose the appropriate silicone material for your business. In this article, we will compare the curing methods, properties, costs, etc. of these two types of silicone, and provide guidance on selecting the better option based on your needs.
What Is Platinum Cured Silicone?
Platinum cured silicone, also known as addition-type silicone, uses platinum compounds to harden the silicone polymer. The curing process of this type of silicone is an addition reaction, so it does not produce any by-products.
Moreover, during the curing process of your silicone product manufacturing, platinum cured silicone produces minimal volatile by-products and typically has very low odor.
It is usually formulated as a two-component system, mixed in equal proportions (by weight, common mixing ratios are 1:1, 10:1), and can cure at room temperature. However, you can accelerate the curing process by heating.
Platinum cured silicone is renowned for its extremely pure and stable properties, making it more suitable for working conditions with high requirements for cleanliness and stability.
What Is Tin Cured Silicone?
Tin cured silicone is a type of condensation-based silicone. It uses organotin compounds as catalysts. The curing process of this silicone is a condensation reaction, and during the curing process, a small molecule is released as a by-product, such as ethanol and water.
Therefore, you will find that tin cured silicone shrinks during the curing process and emits a distinct odor.
The tin cured silicone is usually mixed in a 100:2 ratio. It has outstanding overall cost-effectiveness and is a main type of practical silicone product.
Due to its high cost-effectiveness and ease of use, you can apply it to general mold making and prototype production. However, it is inferior to platinum cured silicone in terms of chemical purity and long-term stability.
The Differences Between Platinum vs Tin Cured Silicone
Key Material Properties
The properties of platinum cured and tin cured silicone resins include shrinkage rate, stability, and temperature resistance, etc. These factors directly determine the lifespan and quality of your final product.
To better meet the customer’s application requirements and control costs, avoiding potential after-sales risks, you can refer to the following table to understand the specific performance comparison:
| Performance Dimension | Platinum Cured Silicone | Tin Cure Silicone |
| Curing Process | Addition reaction, no byproducts | Condensation reaction, releases alcohol |
| Shrinkage Rate | Extremely low (<0.1%) | Relatively high (typically 0.5% -1%) |
| Long-term Stability | Decades (archival grade) | Limited (typically 15 years, prone to brittleness) |
| Temperature Resistance | -60°C to over 200°C | Limited |
| Tensile Strength | Higher (e.g. 890 psi) | Moderate |
| Elongation | Excellent (e.g. 160%) | Moderate |
| Clarity | High transparency | Prone to yellowing |
| Working Time | 5 min/ 30 min/ 2h/ 24h | Product-dependent |
| Demolding Time (Room Temperature) | 18 – 24 hours | Shorter |
Cure Inhibition
One key drawback of platinum cured silicone is the problem of curing inhibition. Because the platinum catalyst loses its activity when it comes into contact with certain chemicals, the silicone cannot cure properly and the affected area becomes sticky and viscous. The specific substances that affect the platinum catalyst you can find in the following table:
| Category | Specific Substances |
| Sulfur-containing Substances | Sulfides, dimethyl disulfide (common in some modeling clays) |
| Tin-containing Substances | Tin fatty acid salts (from tin cured silicone) |
| Amines | Triethylamine, triethanolamine, ethylenediamine, etc. |
| Phosphorus-containing Substances | Triphenylphosphine, phosphites |
| Others | Latex, certain 3D printing resins, solvents with aminebased stabilizers |
If your workshop cannot avoid sulfur-containing substances, we recommend using tin cured silicone instead. Compared with other options, tin cured silicone has a stronger anti-contamination ability and can be cured on sulfur-containing models. However, it is necessary to seal the surface with acrylic spray in advance.
Working Life and Shelf Life
When choosing silicone materials, you should also pay close attention to the inventory lifespan and production lifespan.
Platinum cured silicone generally offers superior long-term stability and aging resistance after curing, and the mold has a longer lifespan; tin cured silicone can only be preserved for 1 to 5 years, and it tends to become brittle later, and the number of times it can be used for casting production varies depending on the application cases.
If you are planning to use it for the mold production of precious cultural relics in museums, platinum cured silicone has a low shrinkage rate and excellent long-term stability, which is suitable for long-term preservation needs.
Cost and Production Efficiency
Because the material cost, mold life, and cycle time directly affect your overall cost. The defect rate and the post-processing stage also relate to production capacity and waste. Choosing the right type can help you optimize the supply chain and increase profits. For a detailed comparison of cost dimensions, please refer to the following table:
| Cost Dimension | Platinum Cure Silicone | Tin Cure Silicone |
| Raw Material Price | Higher (approx. +2050%) | Lower |
| Mold Service Life | Long (no corrosion, less scaling) | Short (frequent mold cleaning required) |
| Defect Rate | Low | Higher (especially for complex parts) |
| Postprocessing | No postcuring required | Commonly required in demanding applications |
Just from the perspective of raw materials, you might think platinum is more expensive. But you should calculate the total cost over the long term. For example, when producing large quantities of precision parts, the cost of platinum cured silicone is lower per unit; while for small batches of rough parts, you have a price advantage by choosing tin cured silicone.
Certification and Compliance
Most of tin cured silicone usually cannot meet food-contact regulatory requirements, such as FDA 21 CFR 177.2600, LFGB (§30 & §31), EU 1935/2004, etc., while the specific formula and the post-curing of platinum cured silicone can pass.
Therefore, for applications involving long-term skin contact, cookware, or other food contact purposes, we do not recommend you choose tin cured silicone.
If you are in the medical industry, it is recommended to choose platinum cured silicone. Because tin cured silicone typically cannot meet USP Class VI or ISO 10993 biocompatibility requirements. However, for RoHS and REACH, by confirming the type of tin and avoiding the use of organic tin, the tin cured silicone can pass the test.
Applications
Platinum Cured Silicone
If you are in the food contact products, infant and children’s products, or medical device industries, you must choose platinum cured silicone for both platinum cured and tin cured silicone.
This is because entering the markets of Europe and the United States requires FDA or LFGB certification, and platinum cured silicone is generally preferred for food-grade and medical applications because it is easier to comply with FDA, LFGB requirements.
When your customers have orders for products with high transparency, color difference sensitivity, or thin-walled precision parts, platinum cured silicone is also your first choice. Specific application examples can be found in the following table:
| Industry / Product Type | Specific Application Examples |
| Food Contact | Baking molds, chocolate molds, ice trays, cake pans |
| Baby Products | Nipples, teething rings, baby spoons, pacifiers |
| Medical Devices | Tubes, face masks, sealing gaskets, prosthetic liners |
| SkinContact / Wearable Items | Watch straps, smart wristbands, eyeglass nose pads |
| SpecialEffects Makeup / Prosthetics | Wound-affect fake skin, prosthetics, masks |
| Sports / Outdoor | Diving mask seals, snorkel mouthpieces, water cup gaskets, swimming caps |
| Pet Products | Chew toys, feeding bowl mats, water dispenser seals |
Tin Cured Silicone
Although tin cured silicone cannot obtain certain certifications, it remains a cost-effective option in many applications. It is suitable for the production of common tools as well as casting with resins like polyurethane and epoxy resin. Tin cured silicone can also be used for casting of wax, plaster, concrete, and low-melting-point metals such as tin, lead-tin alloys.
For ordinary industrial products without food or medical-related certification requirements, choosing tin cured silicone can effectively control costs and ensure the practicality and economy of your products.
| Industry / Product Type | Specific Application Examples |
| Electronics and Electrical Appliances | Buttons, sealing gaskets, shock‑absorbing pads, wire harness seals |
| Industrial Seals | O‑rings, gaskets, oil seals, anti‑vibration pads |
| Mold Making | Resin casting molds, gypsum molds, wax molds |
| Automotive and Marine | Sealing strips, shock‑absorbing blocks, wire harness sheaths |
| Construction and Piping | Expansion joint seals, pipe gaskets |
| Household Goods (Non‑food‑contact) | Remote‑control buttons, anti‑slip mats, drawer bumpers |
| Toys (Non‑ingestible) | Toy wheels, soft rubber accessories |
FAQ
Can Platinum Cure and Tin Cure Silicone Be Mixed?
Absolutely not. Platinum cured silicone cannot be mixed with other curing systems. It will cause the platinum catalyst to fail and be unusable, even if there is a tiny amount of residue.
How to Distinguish Platinum‑Cure from Tin‑Cure Silicone in Cured Products?
There is no simple on-site testing method for this. You can refer to the technical data sheet (TDS) provided by the supplier or request a batch test report. Some laboratory methods such as thermogravimetric analysis and residue detection can help you distinguish, but they are not suitable for daily use.
Can Platinum Cure Silicone Automatically Pass FDA Certification?
Platinum cured silicone does not necessarily come with FDA certification because the FDA’s 21 CFR 177.2600 requires specific migration tests.
Although the platinum system is easier to meet the standards compared to tin cured, you need a specific formula, post-curing, and strict quality control to achieve it. Moreover, your platinum cured silicone products must undergo actual testing.
Can Both Platinum Cure and Tin Cure Systems Be Used for the Same Product?
Although the same product can adopt both platinum curing and tin curing systems in terms of technology, it needs to be molded separately and the process needs to be debugged independently.
This is not only because the combined use will cause the silicone to fail, but also because there are differences in the silicone shrinkage rates of the two systems, and a production mold cannot be shared.
From a practical perspective, using both systems simultaneously will increase the complexity of the SKUs and raise your costs.
Why Does Platinum Cure Silicone Usually Require Vacuum Degassing?
Because platinum cured silicone is prone to trapping air bubbles when you are mixing. If you do not use vacuum degassing before directly pouring, the product after curing will retain air bubbles both inside and on the surface. This not only affects the appearance of your product, but also reduces its mechanical properties.
Final Thoughts
Legensilico is a manufacturer with over 20 years of experience in silicone component production. Our products are sold worldwide. We can provide you with a one-stop service and customize silicone products of various shapes, sizes and colors. If you trust us, feel free to contact us at any time.
