As a silicone tube supplier, I get asked this question every week—sometimes multiple times a day. A customer will see a product spec sheet mentioning “silicone tubing” for a medical device, a food processing line, or even a DIY aquarium project, and they’ll pause: “Wait, what is this stuff actually made of? Is it just plain rubber? Why does it cost more than that cheap vinyl tube I saw online?” I don’t blame them. Most people hear “silicone” and picture that stretchy baking mat or the seal around a wine bottle, but silicone tubes are a far more specialized, engineered material—designed to perform consistently in extreme temperatures, hold up to harsh chemicals, and pass strict safety standards that regular plastics can’t. Today, let’s break this down, straight from the supplier’s perspective who’s spent 12 years mixing, molding, and shipping these tubes to factories and labs across the country. Silicone Tube
First, let’s start with the base: silicone isn’t a natural rubber, and it’s not a plastic—despite what some product labels will tell you. It’s a polymer, but a very specific one called polysiloxane. If you’re into chemistry, that’s a chain of alternating silicon and oxygen atoms, with carbon and hydrogen side groups attached to the silicon. Most other polymers (like polyethylene or PVC) are carbon-based, which is why silicone behaves so differently: it’s flexible down to -100°F, won’t melt until it hits 500°F, and stays stable even when you blast it with a steam cleaner or douse it in rubbing alcohol. That base comes from a raw material called “silicone rubber,” but here’s where it gets layered—because the base alone isn’t what makes a silicone tube work for your specific use case.
When I walk into our production facility, the first thing I see isn’t a big vat of goop—it’s two main components we mix every time, depending on the tube grade: raw silicone base and curing agents. Wait, curing? Let’s explain that simply. Raw silicone is a liquid or soft gel when it’s first mixed, and we have to turn it into the solid, flexible tube you receive. That’s where curing comes in, and this step is everything for quality. For most of our standard and medical-grade tubes, we use platinum-curing systems. This isn’t the old, cheaper “peroxide curing” method some suppliers use to cut costs. Platinum curing uses a tiny amount of a platinum catalyst to trigger the chemical reaction that links the silicone chains together. The benefit here? No leftover byproducts that can leach out. Peroxide curing leaves small traces of organic peroxides, which are a no-go for food or medical applications. A while back, we had a customer who switched to a cheaper peroxide-cured silicone tube for their pediatric feeding pump—and their quality control team rejected 20,000 units because of residual peroxide. That’s the kind of mistake we help customers avoid by sticking to platinum-curing.
But the silicone base itself isn’t just one type. That’s why you’ll hear us talk about “durometer ratings” when we discuss tubes. Durometer measures how hard or soft the silicone is, on a scale of 0 (super soft, like gum) to 100 (hard, like a hockey puck). For example, a soft silicone tube (20A to 30A durometer) is great for medical catheters because it’s gentle on delicate tissue. A medium one (40A to 50A) works for general plumbing or automotive applications, where it needs a little structure but still flexibility. A hard 70A silicone tube is ideal for conveying abrasive materials in industrial lines, because it won’t kink or wear down as fast. The durometer comes from adjusting the molecular weight of the silicone base during production. Higher molecular weight means longer chains, which create a stiffer, more durable tube. Lower molecular weight gives shorter chains, for softer, more pliable tubing.
Now, here’s a part most people don’t know: silicone tubes often have additives mixed in to serve specific purposes. I can’t just dump the base and catalyst into an extruder and call it a day. Additives are what make the tube safe, functional, or long-lasting. Let’s go through the most common ones, because this is where a supplier’s expertise actually matters—generic silicone might work for a craft project, but a custom tube needs targeted additives.
First, thermal stabilizers. If you’re using a silicone tube in an oven conveyor belt or a high-temperature industrial dryer, standard silicone will break down over time, turning yellow, cracking, or releasing fumes. We add small amounts of iron or zinc oxide to the base to boost thermal stability, so the tube can handle 500°F hours on end without failing. For low-temperature applications—like submersible pumps in cold water—we add anti-freeze agents that keep the silicone flexible at -40°F, so it doesn’t get brittle and crack in winter.
Then there are colorants, but not just any food coloring will do. If a tube goes into a food processing line (think soda dispensers or brewery transfer lines), we use FDA-approved, food-grade pigments. Regular pigments can have heavy metals or other contaminants that leach into food or beverage. For medical-grade tubes, we use pigment that’s also USP Class VI certified—meaning it’s non-toxic and won’t cause irritation in the human body. We once had a customer in the craft beer industry bring us a tube they’d used from another supplier: it was bright red, but after a week in their brewery, the red pigment had leached into the beer, turning it pink and ruining a batch that cost them $12,000. That’s why we test every color batch for leachables before it goes into production.
For industrial silicone tubes, we also add fillers to increase tensile strength and resistance to abrasion. Fumed silica is the most common here—it’s a fine, inert powder that acts like a reinforcement, similar to how carbon fiber strengthens a golf club. This is critical for tubes that carry gravel, cement slurry, or other abrasive materials; without fumed silica, the tube would wear through in a matter of days. We also have anti-static additives for electronics applications—silicone is naturally non-conductive, so static electricity can build up inside the tube and damage sensitive circuit components. Adding a small amount of carbon black eliminates static, making these tubes safe for semiconductor manufacturing or electrostatic painting lines.
Wait, but what about medical-grade silicone tubes? That’s a whole separate category, and the materials here are strictly regulated. When you’re making a tube that goes inside a human body, every component has to pass the USP Class VI test, which checks for toxicity, irritation, and sensitization. Medical-grade silicone tubes don’t just use any platinum catalyst—they use a food-grade, medical-grade platinum, with no residual catalysts that could trigger an immune response. They also don’t have any fillers or additives that aren’t explicitly approved for implantable devices. A lot of suppliers will cut corners here, using the same base for general silicone tubes and calling it “medical grade,” but at our facility, we segregate the entire production line for medical grade tubing to avoid cross-contamination with industrial materials. Last year, we supplied a hospital with 50,000 14Fr silicone feeding tubes, and they told us our material passed their 12-month sterility and leachables test—something three other suppliers couldn’t say.
Let’s also address a common myth: some people think silicone tubes are “100% pure silicone.” That’s not true, and even if it were, it might not be a good thing. Pure silicone is very soft and has low tensile strength—if you made a tube out of only pure silicone, it would stretch like a rubber band and break easily under pressure. The additives we add are what balance flexibility with durability. For example, a tube used for blood transfer in a lab needs to be soft to fit over needle hubs, but strong enough to withstand being kinked or pinched without leaking. That balance only comes from mixing the right amount of base, catalyst, and filler.
Now, let’s talk about how these materials come together into the final tube, because that ties back to why suppliers play such a big role in the process. We don’t just sell silicone—we sell a tube that’s engineered for your specific application. For example, a customer in the pharmaceutical industry might need a tube that resists ethanol and is sterilizable with gamma radiation. We’d start with a high-molecular-weight platinum-cured silicone base, add a chemical-resistant filler, and use a pigment that doesn’t fade during sterilization. We’d extrude it to the exact inner and outer diameter they need, and run it through a series of tests to check for tensile strength, chemical resistance, and leachables. That’s not something you can get from a generic plastic supplier; it takes specialized knowledge of silicone’s material properties.
I see this every day: customers come to us frustrated because they bought a cheap silicone tube online for their aquarium, and it turned yellow or leached into the water. When we look at what that tube is made of, it’s low-grade silicone with cheap peroxide curing, no thermal stabilizers, and untested colorants. We tell them, “That’s not a silicone tube designed for long-term water use—this is.” The difference is in the materials, and that’s why paying a little more for a reputable silicone tube supplier is worth it.
So, to sum up, silicone tubes are made from a custom blend of polysiloxane base, platinum curing agents, and specialized additives tailored to their intended use. The base is a silicon-oxygen polymer, unlike carbon-based plastics or rubbers, which gives silicone its unique temperature stability and flexibility. The curing process ensures no harmful byproducts, critical for food and medical applications. Additives like thermal stabilizers, fillers, and FDA-approved colorants enhance performance, strength, and safety.
At the end of the day, if you’re shopping for a silicone tube, don’t just look for the word “silicone” on the package. Ask the supplier: What’s the curing agent? Is it food-grade? What additives are included? That’s the information that tells you if the tube is up to your standards. We’ve spent years refining our material blends because we know that a tube that fails isn’t just a product—it can cause product spoilage, equipment damage, or even harm to people.
If you’re in need of a custom silicone tube, a standard size for your line, or just have questions about what materials will work best for your project, we’re here to help. Reach out to our team to discuss your requirements, and we’ll share detailed material specs, test results, and a tailored quote that fits your needs.
Cap and Septa References
- "Silicone Elastomers: Properties and Applications," Dow Corning Corporation, 2022.
- "USP Class VI Plastic Materials Testing Guidelines," United States Pharmacopeia, 2021.
- "Medical Grade Silicone Tubing: Manufacturing and Compliance," International Organization for Standardization (ISO) 10993, 2020.
- "Additives for Silicone Polymers," Society of Plastics Engineers (SPE), 2019.
Rufluor Sealing Tech (Ningbo) Co., Ltd.
With abundant experience, we are one of the most professional silicone tube manufacturers and suppliers in China. Please rest assured to wholesale high quality silicone tube made in China here from our factory. We also accept customized orders.
Address: No.37, Shiji Road, Mazhu, Yuyao, Zhejiang
E-mail: andy@rufluor.com
WebSite: https://www.rufluor.com/
