The sealing ring is the least noticeable product among silicone products. It is usually hidden inside the equipment and is not visible to users, nor do they pay special attention to it.
However, this insignificant small part, once it ages and fails, may cause water leakage, air leakage, equipment malfunctions, and even require the entire batch of products to be recalled.
Many customers have reported the same issue to us: the sealing rings that look similar when purchased, some lasted for two or three years without any problems, while others became hard, cracked, and lost their sealing effect within three months of installation.
Today, let's talk about: Why do the lifetimes of the same silicone sealing rings vary so much?
First, let's look at what aging looks like
Silicone sealing rings age in several ways:
Hardening: The originally soft sealing ring becomes hard and does not have elasticity when pressed
Cracking: Fine cracks appear on the surface, and in severe cases, it will break
Deformation: The original shape is lost, and it does not spring back after being compressed
Sticking: The surface becomes sticky, and it may even stick to the contact surface
Any of these situations will significantly reduce the sealing effect. The reasons for aging often lie in the purchasing process already.
The reasons for silicone ring aging
Reason one: Different raw material grades
This is the most fundamental difference.
Silicone raw materials are classified into many grades based on their application and performance. The same "silicone" used in ordinary industrial scenarios and in scenarios with high temperatures, oil resistance, and long-term pressure has completely different formulas and costs.
Some low-priced sealing rings use ordinary precipitation method silicone, which is low in cost but has limited temperature resistance and anti-aging performance. While high-quality sealing rings usually use gas-phase silicone, which has a more stable molecular structure and significantly stronger anti-aging ability.
Customers' intuitive perception is: The cheap sealing rings work fine at first, but after a long time, they become hard and crack; the better ones still maintain a stable state for several years.
How to determine: Ask the supplier about the type of raw material when purchasing. A quotation sheet that only says "silicone" is not sufficient for information.
Reason two: Different levels of vulcanization
Vulcanization is the key step in shaping silicone. The degree of vulcanization directly determines how long the sealing ring can be used.
Sealing rings with insufficient vulcanization have substances that have not fully reacted inside. These substances will slowly precipitate during use, causing the sealing ring to harden, become sticky, and lose elasticity. More seriously, sealing rings with insufficient vulcanization lose their rebound ability very quickly under long-term pressure, and after a period of time, they become flattened, and the sealing effect naturally decreases.
Vulcanization cannot be seen externally, but it becomes apparent after a period of use. This is why some sealing rings "work fine when installed, but start to have problems after three months".
How to determine: Ask the factory about the vulcanization temperature and time, and whether there is a process record. Honest factories can explain clearly, while those that are vague should be cautious.
Reason three: Whether the formula matches the usage environment
The usage environment of the sealing ring varies greatly:
Some are in contact with high temperatures (such as in household appliances and engine areas of cars)
Some are in contact with oils (such as in mechanical equipment)
Some are in a compressed state (such as in waterproof structures)
Some are exposed to the outdoors, affected by ultraviolet rays and temperature differences
Different usage environments require different silicone formulas. Formulas for high-temperature resistance, oil resistance, and resistance to permanent compression, have different components and costs.
If the factory does not consider the usage environment and uses a universal formula for all orders, there may be no problems in the short term, but there will definitely be problems in the long run. Using the wrong formula, even the best raw materials cannot withstand it.
How to determine: When purchasing, clearly state the usage environment - temperature range, what medium it contacts, and whether it needs to be compressed for a long time. Reliable factories will recommend appropriate formulas based on this information, rather than saying "all are the same" in one sentence.
After the silicone seal ring is formed, it usually requires a second curing process - being baked at a high temperature for a certain period of time.
The purpose of this step is to allow the silicone to fully stabilize and remove any residual low-molecular substances. Sealed rings that have undergone this second curing process have more stable performance and a slower aging rate. Omitting this step would result in lower costs but also shorter product lifespan.
How to determine this: Ask the question "Was the second curing process carried out?" This question is rarely asked by many customers, but it is precisely a detail that distinguishes the level of factory standardization.
Reason number five: Storage and transportation conditions
This point is often overlooked, but it does affect the lifespan.
Silicone seal rings have requirements for storage conditions: avoid high temperatures, avoid direct sunlight, and avoid mixing with oil-based chemicals. If the factory warehouse conditions are poor, or if the seal ring is exposed to sunlight or moisture during transportation, its performance may already be compromised when it reaches the customer.
How to determine this: During on-site inspections, take a look at the warehouse. Is the seal ring stored separately, is it protected from light and heat, and is the packaging intact? These details can reflect the management level of the factory.
How does Hongxianda manufacture seal rings?
At Hongxianda, we manufacture functional silicone parts like seal rings, and we have several basic principles:
Raw materials are not compromised. Select appropriate raw materials based on the usage environment. Use the gas-phase method when necessary, and avoid the sedimentation method when not needed. Be clear about the requirements for high-temperature resistance when necessary.
Curing has standards. Each product has clear curing parameters, and the production process is recorded to ensure adequate curing.
The formula depends on the scenario. The customer provides usage conditions, and we recommend a matching formula. Do not use one formula for all.
Post-processing is not omitted. For products that require a second curing process, no steps are skipped.
Although the seal ring is small, it is responsible for the sealing function. If the seal fails, the entire product may have problems. This account is clearly calculated by the customer, and we also calculate it clearly.
Finally, a few words:
Seal rings may look the same, but the difference in lifespan is hidden in the invisible aspects of raw materials, curing, formula, and post-processing.
Cheap seal rings save costs but sacrifice lifespan. When they age and fail after three months and require equipment repair, the money saved has already been lost.
If you are purchasing silicone seal rings or are dissatisfied with the lifespan of the products from your current supplier, please come and chat with Hongxianda. Let us know the usage environment, and we will help you select the right materials and do the right process.