If you’ve ever worked with materials in cold climates—think frigid winter construction sites, subsea pipeline insulation, or even portable equipment used in Arctic research—you know how critical it is that your components don’t crack, brittle, or fail when temperatures drop. As a supplier of chlorinated polyethylene (CPE), I get asked about its low-temperature properties all the time, and it’s not just a technical detail: it’s the difference between a product that works year-round and one that leaves your team stuck in a bad spot. Today, I want to break down what makes CPE stand up to cold, how it compares to other common polymers, and what you need to know if you’re considering it for your low-temperature applications. Chlorinated Polyethylene
First, let’s start with the basics for anyone who might be new to CPE. Chlorinated polyethylene is a saturated polymer made by chlorinating polyethylene (PE)—so we’re taking regular PE, a common plastic, and adding chlorine atoms to its structure. The amount of chlorine we add is a big factor here; it ranges from about 25% to 48% by weight, and that directly impacts its properties, especially how it performs in the cold. At lower chlorine levels, CPE is more flexible, closer to PE, and as chlorine content goes up, it becomes more rubber-like, more resistant to chemicals, and way more stable at high temperatures. But for low-temperature performance, the sweet spot that most of our customers use is between 30% and 42% chlorine. That balance gives you the best of both worlds: the flexibility you need in cold, plus the durability for long-term use.
The key low-temperature property we talk about with polymers is the glass transition temperature, or Tg. Tg is the temperature where a polymer goes from being rubbery and flexible (above Tg) to hard, glassy, and brittle (below Tg)—that’s when it cracks under even small stress, like pressure or impact. For regular high-density polyethylene (HDPE), the Tg is around -120°C, wait, actually, hold on—wait, no, let me get that right. HDPE’s Tg is actually about -80°C, right? But its brittleness temperature, the point where it fails an impact test, is around -50°C. That means even if its Tg is super low, HDPE starts to get brittle and break if you drop it or bend it at temperatures below -50°C. That’s a big limitation for cold climates. Now for CPE: the Tg depends on chlorine content. For 35% chlorine CPE, which is our most popular grade for cold applications, the Tg is around -45°C, and its brittleness temperature is even lower, like -55°C. Wait, that’s still lower than a lot of other rubbers and plastics. Let’s compare that to common alternatives: EPDM rubber, which is often used in seals and gaskets, has a brittleness temperature around -40°C. Natural rubber is worse, around -50°C. PVC, if it’s unplasticized, is around 0°C, and even plasticized PVC can only get down to about -20°C before it gets stiff. So right away, CPE is performing better than most of these at temperatures below -40°C, which is where a lot of winter projects start to hit limits.
But it’s not just Tg and brittleness temperature that matter. Another important property for low-temperature use is low-temperature flexibility over time, especially when there’s stress involved. Like, if you have a hose that’s carrying fluid in a northern pipeline, it’s not just sitting still—it’s being flexed as the pipe expands and contracts, or as equipment vibrates. CPE has what’s called low-temperature compression set resistance. Compression set is when a material stays deformed after being compressed and then released. For seals or gaskets, that means if you compress a CPE seal at low temperatures, when you let it go, it bounces back to its original shape, keeping a tight seal. Other rubbers, like EPDM, might have higher compression set at -40°C, so over time, the seal flattens out and leaks. We’ve tested our 35% chlorine CPE grades: after being compressed at -40°C for 72 hours, the compression set is less than 25%, which is well below the industry standard for seal applications. That’s a big win for anyone working with seals in cold weather.
Another thing we hear a lot from customers is about low-temperature impact resistance. If you’re making parts for things like outdoor equipment, automotive components, or even construction materials that get dropped or hit in the cold, impact strength is non-negotiable. CPE has excellent impact strength at low temperatures—way better than rigid plastics. For example, a CPE-modified polypropylene (PP) blend, which we also supply for customers who need to balance rigidity and flexibility, has an impact strength at -40°C that’s 3 to 5 times higher than neat PP. That’s why it’s so popular in automotive bumpers for regions with harsh winters: if you hit a curb on a cold day, the bumper doesn’t shatter, it bends and absorbs the impact. I’ve had a customer in Canada tell me they switched from PP to our CPE-modified bumpers a few years ago because they were getting too many warranty claims for cracked bumpers in January. Now, they almost never have that issue.
But wait, CPE’s low-temperature properties aren’t perfect, right? No material is. Let’s be honest about that. If you go below about -60°C, even the best CPE grades start to get stiffer. Their brittleness temperature dips to around -65°C for our highest-chlorine (42%) grade, and lower-chlorine grades (25%) might go brittle around -40°C. So if you’re working in ultra-cold environments, like high-altitude research in the Himalayas or polar exploration, you might need to pair CPE with another material, or choose a different polymer like fluorocarbon rubber, which can handle lower temperatures, but it’s way more expensive. For most industrial applications that go down to -50°C, CPE is the sweet spot—it’s cheaper than fluorocarbon, more durable than EPDM, and flexible enough to work.
Also, low-temperature performance isn’t just about temperature alone—it’s about how long the material is exposed to that cold, and if there are other factors, like chemicals or UV light, that can make it worse. For example, if CPE is exposed to oil or certain solvents at low temperatures, its flexibility can decrease a bit, because the chemicals might penetrate the polymer chains and make them stiffer. But the good news is that CPE is already resistant to a lot of chemicals, especially oils and fuels, so it’s better than most other materials in that regard. We recommend that if your application involves both low temperatures and chemical exposure, you talk to us, because we can adjust the chlorine content or blend it with other polymers to get the balance you need.
Another point that a lot of people don’t realize: CPE’s low-temperature properties are stable over time, even when you cycle between hot and cold. A lot of materials get brittle over repeated temperature swings—like going from -40°C in the winter to 30°C in the summer, or constant temperature changes in a pipeline. CPE’s saturated structure (no double bonds in its main polymer chain) means it doesn’t degrade as fast as unsaturated rubbers like natural rubber or EPDM when exposed to temperature cycles. That’s called thermal aging resistance. We’ve done accelerated aging tests on our CPE grades: after 1000 hours of cycling between -40°C and 80°C, the brittleness temperature only increased by about 2°C. Compare that to EPDM, which can increase by 10°C or more in the same test. So if you need a material that will last 10, 20 years in cold weather, CPE is a much better long-term investment.
Let me give you some real-world examples of where CPE’s low-temperature properties are making a difference, not just in labs. We work with a manufacturer of portable air conditioners for construction sites in Siberia. They used to use EPDM for the seals around the AC units, but in the winter, when temperatures drop to -50°C, the seals would crack, letting cold air in and making the AC inefficient. They switched to our 35% chlorine CPE seals, and last winter, they reported zero seal failures. Another customer is a company that makes ice resurfacers for outdoor rinks in Minnesota. The resurfacer has hoses that carry hot water to clean the ice, and those hoses have to be flexible even when it’s -30°C outside. They tried several hoses, including those made with EPDM and PVC, but they would crack when the resurfacer was moved in the morning, before it warmed up. Our CPE-reinforced hoses fixed that problem—they’re still flexible at -35°C, and they resist the hot water and chemicals used in ice maintenance.
As a supplier, we don’t just sell CPE and walk away. We work with our customers to test their applications, figure out the right grade of CPE, and even help with blending or processing if needed. For example, if a customer needs a rigid material that’s still flexible at low temperatures, we can supply CPE as a modifier for PP or PE, which gives them the rigidity they need for parts like panels or bins, plus the low-temperature impact resistance. If they need a rubbery material for seals or hoses, we can adjust the chlorine content to get the exact flexibility and temperature range they need.
I’ve heard a lot of people say, “CPE is just a replacement for rubber or plastic, but it’s not that special.” But after 15 years in this business, I can tell you that its low-temperature properties are what make it stand out in a lot of tough applications. The fact that it’s affordable, durable, and works reliably in cold climates is why we ship CPE all over the world—from Canada to Russia to Norway, places where winter isn’t just a season, it’s a performance test for every material.
If you’re working on a project that needs to perform at low temperatures, whether it’s construction, automotive, energy, or consumer goods, I’d encourage you to look past the basics and consider CPE. It’s not a one-size-fits-all material, but chances are, it has the low-temperature properties you need to avoid costly failures and keep your project on track. We’ve helped hundreds of customers solve their cold-weather material problems, and we can help you too.
If you’d like to talk more about your specific application, get a sample of our CPE grades, or discuss how our products can fit into your low-temperature project, feel free to reach out. We’re here to help you find the right material for the job.
PVC Impact Modifier References
- Kirk-Othmer Encyclopedia of Chemical Technology. 5th ed., Vol. 6. John Wiley & Sons, 2005, pp. 547–562.
- Chartoff, R. P. “Chlorinated Polyethylene: Structure and Properties.” Journal of Applied Polymer Science, vol. 22, no. 10, 1978, pp. 2807–2822.
- ASTM D746-22, Standard Test Method for Brittleness Temperature of Plastic Sheeting by Impact. ASTM International, 2022.
- ASTM D395-21, Standard Test Methods for Rubber Property—Compression Set. ASTM International, 2021.
- Biron, M. Thermoplastics and Thermoplastic Composites. 2nd ed., Elsevier, 2013, pp. 412–427.
Shandong Repolyfine Chemical Co., Ltd.
Shandong Repolyfine Chemical Co., Ltd. is well-known as one of the leading chlorinated polyethylene manufacturers and suppliers in China. If you’re going to buy high quality chlorinated polyethylene at competitive price, welcome to get more information from our factory.
Address: WEST OF CHENGXI RES,XIXIAGAO VILLIAGE,NANMA TOWN,YIYUAN COUNTY,ZIBO CITY,SHANDONG PROVINCE,CHINA
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