When I first started working as a silicone parts supplier 12 years ago, the question I heard most from my clients wasn’t “How long do these parts last?” It was “Why did my silicone seal tear after 3 months?” Back then, I’d just point to the material specs sheet and say, “That’s standard silicone.” I thought crosslink density was the only number that mattered. Then a client in the automotive industry sent me a broken engine gasket that had split along its edge, and that’s when I realized wear resistance wasn’t just a spec—it was the make-or-break difference between a part that worked and a part that cost someone their job. Silicone Parts
Over the years, I’ve spent countless afternoons in our small testing lab, running abrasion tests on every batch we make, talking to engineers in packaging, medical devices, and aerospace, and learning that improving silicone wear resistance isn’t about one trick—it’s about matching the material to the application, tweaking the formulation, and how you process it when it’s made. Today, I want to walk through what actually works, no fancy marketing jargon, just the lessons we’ve learned serving hundreds of businesses that rely on silicone parts that hold up.
First, let’s get one thing straight: silicone, in its pure, unmodified form, isn’t the most wear-resistant polymer out there. It has great heat resistance and flexibility, but its low surface energy and relatively soft molecular structure mean it can scuff, tear, or degrade when it rubs against another material repeatedly. That’s why if you’re using silicone for a part that moves—like a door seal that rubs against a car frame, a medical catheter that slides through tissue, or a conveyor belt roller in a packaging line—pure silicone will likely wear out faster than you want.
The biggest mistake I see new clients make is assuming adding filler is just a matter of throwing more stuff into the mix. But fillers are the backbone of wear resistance, and not all fillers are created equal. For years, we used regular calcium carbonate as a cheap filler, but it made the silicone brittle, and parts would crack when they bent, not just wear down. Then we switched to fumed silica—finer particle size, more uniform, and it bonds well with silicone’s polymer chains. The difference was night and day: our seal parts went from lasting 10,000 flex cycles to over 50,000, according to our lab tests. But fumed silica is just the start. For parts that see heavy abrasion, like those used in mining or heavy equipment, we add molybdenum disulfide, a dry lubricant that reduces friction between the silicone and the surface it’s rubbing against. One client in agricultural machinery told us their silicone seal for a hay baler used to wear out in 2 months; after we added a small amount of molybdenum disulfide to their formulation, it’s now lasted over 18 months in the field.
But here’s a balance most people miss: too much filler, or the wrong type, hurts flexibility and tear strength. A client making medical silicone buttons once asked us to triple the filler content because they wanted it to not scuff when used with medical gloves. The result? The button was so stiff it broke when the doctor pressed it. We had to adjust: instead of loading up on one filler, we used a mix of fumed silica for reinforcement and a small amount of polytetrafluoroethylene (PTFE) micro-particles. PTFE is self-lubricating, so it cuts down on friction without making the silicone hard. That button now goes through 10,000 uses without scuffing, and still feels soft enough for clinical use.
Next, crosslinking—this is another area where we’ve seen huge gains, but it’s not just about increasing crosslink density. When I first started, we used peroxide curing for most of our parts, which gives good crosslinking, but it leaves small byproducts that can weaken the surface of the silicone, making it more prone to wear. About 8 years ago, we switched to platinum-curing for most grades, especially for parts that need high wear resistance. Platinum curing creates more uniform crosslinking throughout the part, not just on the surface, and the byproducts are inert, so the surface is harder and more resistant to abrasion. We tested the same silicone formulation, one cured with peroxide and one with platinum, on an abrasion tester that rubs a weighted sandpaper pad back and forth across the part. The platinum-cured part lost half its mass after 1,000 cycles; the peroxide-cured one lost three times that much.
But crosslinking isn’t just about the curing agent. The temperature and pressure during molding matter too. If you under-cure a silicone part, the crosslinks don’t form all the way, and the surface is soft and sticky, so it wears almost immediately. We learned this the hard way with a client that ordered 500 silicone gaskets for a food packaging line. They ran them through a molding cycle that was 20% shorter than our standard, and within a week, half the gaskets had scuffed so bad they were leaking. Now, we have a strict cure profile for every wear-resistant grade, and we test every batch with a durometer and a small abrasion check before it leaves our facility. Over-curing is a problem too—it makes the part brittle. We once had a aerospace client whose silicone O-rings were cracking after a few uses, and it turned out their supplier had over-cured the parts to make them harder, which made them more prone to tearing when they rubbed against metal surfaces. We adjusted our cure time, and the O-rings now last twice as long.
Surface treatment is the final piece of the puzzle, and it’s the one that’s often overlooked. Even if your internal formulation and crosslinking are perfect, a silicone part’s surface can still be too soft for heavy use. We tried plasma treatment a few years ago, and I was skeptical at first—it sounded like a fancy trick. But for parts that need to slide or rub, plasma treatment changes the surface of the silicone without messing with its flexibility. We use oxygen plasma for most of our wear-resistant silicone parts; it etches the surface slightly, increasing the surface energy and creating a tiny, hard layer that resists abrasion. One client making silicone gaskets for refrigerators told us their old gaskets would wear along the edge where they met the door frame, leaving marks on the paint. After we added a light plasma treatment to our standard gasket formulation, those edge marks stopped completely. We’ve also experimented with adding a thin PTFE coating to the surface for parts that see very heavy friction, like conveyor belt pads. The coating is only a few microns thick, so it doesn’t affect the silicone’s flexibility, but it cuts friction by 70% according to our in-house friction tests. A packaging client used to replace their conveyor pads every 3 months; now they’ve gone over a year without changing them, saving them thousands in replacement costs.
But here’s the thing: every application is different, so there’s no one-size-fits-all solution. A medical catheter needs different wear resistance than a heavy equipment seal, and a silicone part used in a high-temperature oven needs different modifications than one used in cold storage. We recently worked with a client making silicone parts for underwater drones. The parts had to resist both abrasion from saltwater and impact from sea debris, and they had to be flexible enough to bend as the drone moved. We tried several formulations: fumed silica alone, fumed silica plus PTFE, then added a small amount of carbon fiber to increase impact resistance. The carbon fiber didn’t make the silicone brittle, and it added enough strength that the parts didn’t tear when they hit small rocks. We adjusted the cure time to balance hardness and flexibility, and after testing in a saltwater tank for 6 months, the parts showed almost no wear, while the old parts the client was using had scuffed badly in 2 weeks.
I always tell my clients that improving silicone wear resistance isn’t about making it indestructible—it’s about making it last as long as your application needs it to. If a part is only going to be used a few times a month, you don’t need to add expensive fillers or plasma treat it; that would just add unnecessary cost. If it’s going to rub against a metal surface thousands of times a day, you need to invest in the right formulation and processing.
We’ve been making silicone parts for 12 years, and the biggest feedback we get from happy clients is that our parts don’t wear out when everyone says they should. That’s not luck—it’s testing every idea, learning from the mistakes, and adjusting for each specific need. Whether you’re making a medical device that needs to withstand thousands of uses, an automotive part that needs to resist heat and friction, or an industrial part that works in harsh conditions, we have experience adapting silicone formulations to meet your wear resistance requirements.
If you’re tired of silicone parts that wear out too fast, cost you downtime, or need frequent replacements, let’s talk. We can work with your specific application, run tests to see what formulation and processing will give you the wear resistance you need, and create parts that fit your budget and performance needs. No generic specs, no one-size-fits-all solutions, just silicone parts that work as long as you need them to.
Cap and Septa References
Ash, B. J., Schadler, L. S., & Siegel, R. W. (2004). Mechanical properties of nanocomposites. Springer.
Mark, J. E. (1999). Polymer data handbook. Oxford University Press.
Oss, C. J. V. (1994). Surface energy of polymers. Wiley.
Stevens, M. P. (1999). Polymer chemistry: An introduction. Oxford University Press.
Rufluor Sealing Tech (Ningbo) Co., Ltd.
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