When you are working on a silicone rubber project, but are unsure about the lifespan of silicone or how to select a silicone material with greater longevity. Don’t worry! This article will explain the factors that affect silicone’s lifespan and how to extend it, then guide you to the most suitable silicone manufacturer and the silicone for your project.
Factors Affecting Silicone Rubber Lifespan
Silicone Thermal Fatigue
Although silicone possesses the advantage of high-temperature resistance, prolonged exposure to high temperatures—or environments involving thermal cycling—causes its internal molecular chains to suffer from fatigue and eventually fracture.
Consequently, the process by which silicone loses its elasticity marks the gradual decline of its service life.
When silicone is utilized in components for engines or high-power electric motors, specifically the repeated starting and stopping, it subjects the material to thermal expansion during heating and contraction during cooling.
Over time, these frequent temperature fluctuations induce slight cracks on the surface of the silicone. This serves as an indication that the material is nearing the end of its service life.
Compression Set
The second key factor affecting the lifespan of silicone is its resilience. The prolonged compression will eventually decrease its elasticity.
The molecular structure of silicone is an intricate network composed of molecular springs. The outward thrust generated when these springs are compressed constitutes the material’s resilience, like springs.
However, under prolonged compression, these molecular chains begin to rearrange their structure due to stress relaxation. Then they gradually habituate themselves to their flattened state, losing the capability to spring back, which ultimately results in compression set—a condition that signifies the end of the silicone’s service life.
Chemical Incompatibility
When silicone comes into contact with certain chemicals, these substances penetrate its molecular structure, shortening silicone’s service life—or even leading to complete failure. It significantly diminishes the silicone’s tear strength, thereby reducing its overall lifespan.
Therefore, you need to carefully avoid contact with non-polar solvents (such as fuels or mineral oils) or strong acids and bases, which can induce your silicone products to become tacky, soften, or even crack.
Ozone & UV Exposure
Exposure to high-intensity outdoor UV radiation or to ozone generated by electric motors can compromise silicone’s durability.
Prolonged UV exposure causes the molecular chains in the surface layer to fracture, resulting in a loss of material elasticity; meanwhile, ozone triggers surface oxidation, leading to the formation of microscopic cracks, which could shorten the lifespan of the silicone.
If your product is intended for outdoor use, please be sure not to overlook the risks of leakage in electrical infrastructure due to dirt and moisture subsequently accumulating within fissures.
How to Extend Silicone Rubber Lifespan
Depending on the specific applications, there are various methods suitable for different situations to extend the lifespan of silicone.
Upgrading Processing Techniques
The manufacturing process of standard silicone or its usage over extended periods can generate byproducts. Then these byproducts. Over time, acidic substances attack the molecular chains, causing the silicone to become brittle. Ultimately, this leads to parts failing before reaching their promised service life.
Upgrading the silicone vulcanization process can effectively address this issue. We recommend platinum curing.
The platinum curing process endows silicone with exceptional tear strength and fatigue resistance. In industrial applications—particularly those involving repetitive start-and-stop cycles, or instances where the silicone is subjected to frequent stretching or bending—platinum-cured silicone effectively delays the formation of cracks, thereby preventing the material from fracturing prematurely.
Enhancing Surface Protection
Silicone possesses a high COF will direct contact with skin or clothing, generating significant friction. Thus, a specialized coating such as PU/Feel Coating can be applied to the silicone surface to mitigate the loss from prolonged friction—thereby preventing the silicone from thinning or becoming polished.
For manufacturers engaged in the production of smartwatch bands, mobile phone cases, and earbud covers, this method serves to extend the lifespan of your products.
In the context of outdoor equipment, silicone that is subjected to prolonged exposure to UV radiation is prone to manifesting as chalking and cracking. For outdoor equipment manufacturers concerned about this issue, we recommend incorporating UV stabilizers into your raw material to provide enhanced protection for the expensive internal electronic components of your devices.
Scientific Storage Methods
No matter how superior silicone’s properties may be, proper storage methods are essential to preserve their lifespan. Many manufacturers allow the service life of their silicone products to be partially compromised during warehousing, before the goods even reach the end user.
Prolonged exposure of silicone materials to sunlight or to poorly ventilated environments accelerates surface oxidation. This leads to premature hardening of the material, effectively shortening its original three-year lifespan to just one year.
Therefore, we strongly recommend ensuring proper ventilation in your warehouse and storing the products away from direct light.
Prolonged exposure to air causes the active additives within the silicone to volatilize, resulting in the material prematurely losing its physical properties.
Therefore, we highly recommend vacuum packaging or airtight sealing.
Products requiring such careful storage include food-grade silicone seals, self-adhesive silicone sheets, ultra-soft silicone, and similar materials.
How to Select Silicone Rubber for Longer Lifespan
Based on your product characteristics and your customer needs, find the most suitable solution for extending the lifespan of your silicone.
Optimizing Material
Platinum or Peroxide
If your products are subjected to consistently compressive stress—such as seals for EV battery packs or gaskets for avionics equipment—they require long-term sealing integrity and high resilience. Platinum-cured silicone is your best choice.
Conversely, if you have a limited budget and prioritize cost-effectiveness, peroxide-cured silicone will suit. Its raw material costs less, and its processing techniques are well-established. However, peroxide-cured silicone lacks the exceptional compressive resilience and rebound properties of its platinum-cured counterpart—qualities essential for extending the material’s service life.
Special Addition
After you have understood which manufacturing process is best suited to your needs, we can also incorporate specialized materials to address specific applications.
If your product is required to withstand temperatures over 180°C, we recommend incorporating heat stabilizers. This ensures long-term stability under such conditions, thereby preventing a premature end to the product’s service life.
For applications such as outdoor base stations or environmental monitoring equipment, we recommend the addition of UV stabilizers. An inclusion level of merely 2% is sufficient to prevent the silicone material from undergoing embrittlement reactions during prolonged exposure to ultraviolet radiation.
Preventing the premature embrittlement of silicone materials is an effective method for extending their overall lifespan.
Hardness
For different products, the specific hardness requirements for the silicone used are critical to maintaining the product’s service life.
Consequently, products subjected to frequent movement typically require superior resilience and fatigue resistance, for which the hardness is generally controlled within the 30–50 Shore A range.
In this scenario, selecting a material with excessive hardness will result in fatigue fracture after just a few thousand cycles. A hardness range of 30–50 Shore A offers excellent fatigue resistance and resilience, thereby extending the number of dynamic cycles.
Conversely, for products where requires support and abrasion resistance, we recommend a silicone hardness of 60–80 Shore A.
Exceptional support and abrasion resistance extend the period of structural stability, which prolongs service life.
Quick Testing for Lifespan
To verify the quality of silicone samples, these testing techniques will be useful.
Heating Aging Test
Accelerated Aging Tests are designed to rapidly validate product performance without the need to wait for years to observe the actual aging of silicone to analyze its service life.
You simply need to place your samples in a precision oven at 150°C for 70 to 72 hours. If, after 72 hours, the hardness changes by more than ±5–10 Shore A, or the tensile strength decreases by more than 25%, the material poses a significant risk to its stability in normal-temperature applications.
Compression Set Test
Compress the sample to 75% of its original height and place it in a precision oven at 175°C for a duration of 22 or 72 hours. Finally, allow the sample to rest at room temperature for 30 minutes to recover naturally.
If the recovery rate falls below 80%, the sample is considered to have failed. Because in actual service, over time, this resilience will further attenuate to 70% or 60%.This will result in the product reaching the end of its service life prematurely.
Thermal Cycling Stress Test
To assess a product’s thermal fatigue performance, a rapid-switching thermal cycling test is conducted within a temperature range of -40°C to +200°C. The samples are inspected after 500 and 1,000 cycles to determine whether any cracks have appeared.
If microcracks appear after just 500 cycles, it implies that, in practical applications, the material could fracture within one to two years due to stresses induced by thermal expansion and contraction.
This is a direct method for testing automotive-grade silicone hoses and gaskets.
FAQ
How Do You Determine the Service Life of a Silicone Gasket? Can It Still Be Used Once It Has Flattened Out?
When a gasket loses its resilience, which means it undergoes compression set, its sealing function has effectively failed. Once the deformation exceeds 20–30% of its original thickness, creating a risk of leakage. Before procurement, you may request that the supplier provide results from compression set tests. If the recovery rate falls below 80%, the material is unsuitable for critical sealing applications requiring a service life of five years or more.
How Can One Visually Determine Whether Silicone Has Sustained Irreversible Chemical Damage?
We recommend respecting the material’s surface texture and tactile feel. If cracks are present and their edges appear clean and sharp, they typically result from a sudden external tearing force, indicating that the material itself has not yet deteriorated. However, if the surface exhibits powdering (leaving a white residue when you rub), becomes tacky, or craze, this signifies that the material has lost over 70% of its insulating properties.
In such cases, it must be replaced immediately.
If Silicone Swells and Is Removed from the Oil Environment, Can Its Lifespan Be Restored?
No, it’s not. The swelling process refers to more than just an increase in volume; oil molecules actually penetrate the silicone’s molecular structure. Even if the material is removed from the oil environment, its internal physical properties have already undergone irreversible changes.
Consequently, its tear strength and sealing pressure cannot be restored to their original levels. Once significant swelling occurs (defined as a volume increase exceeding 15%), the component should be considered to have failed.
Final Thoughts
Understanding the factors that affect silicone lifespan, as well as offering the proper selection methods, will help you choose the silicone best suited for your needs. If you are looking for the right silicone for your project, or if you have any further questions regarding silicone lifespan, please submit an inquiry to Legensilicone. We offer comprehensive, one-stop service and will develop a customized solution to your project requirements.
