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Rubber aging is irreversible degradation (tackiness, embrittlement, cracking, powdering) after storage or use. It has five trigger-based categories, with causes and failure features below: 1. Oxygen & Ozone Aging (Failures: surface cracking, fracture) Causes: Oxygen in air and environmental ozone (ozone far more aggressive); rubbers with C=C bonds (NR, NBR, etc.) are highly sensitive. Symptoms: Fine surface cracks; under tension, cracks propagate perpendicular to stress, leading to fracture. Oxygen causes either chain scission (softening/stickiness) or excessive crosslinking (hardening/brittleness). Ozone specifically attacks deformed rubber surfaces, creating irreversible cracks. 2. Thermal Aging (Failures: high-temperature hardening, melting/tackiness) Causes: Sustained high heat in engine compartments or high-temperature environments. Symptoms: Two opposite effects – NBR and BR undergo crosslinking, becoming hard and brittle like plastic, breaking easily when bent; NR network disintegrates under heat, becoming soft and sticky like melted adhesive. Heat accelerates molecular motion, breaks polysulfide bonds, and significantly reduces tensile strength and resilience. 3. Light & Weathering Aging (Failures: powdering, fading, cracking) Causes: Outdoor UV, rain, and alternating temperature/humidity cycles. Symptoms: Gloss loss, fading (black turns grayish, colored turns white), surface powdering and flaking, accompanied by fine cracks. UV cuts polymer chains; combined with rain-soaking and thermal cycling, the surface layer rapidly loosens and loses toughness. 4. Mechanical Fatigue Aging (Failures: internal heat melting, localized cracking/chunk loss) Causes: Long-term repeated tension, compression, and high-frequency vibration on mounts, tires, drive components, etc. Symptoms: Friction between polymer chains and carbon black generates heat. Poor compounding or high heat-generation formulas, combined with inadequate heat dissipation, cause internal heat accumulation and self-accelerated aging, greatly shortening service life. 5. Medium-Induced Aging (Failures: swelling, exudation-induced hardening/shrinkage) Causes: Long-term contact with oils, hydraulic fluids, acids/alkalis, water, and other liquid media. Symptoms: Seals swell and soften in oils; additives and plasticizers are leached out, causing hardening and shrinkage, leading to complete seal failure. Media penetrate molecular gaps, disrupt the crosslinked network, and ultimately cause leakage and material damage.

I. It’s No Coincidence That Your Car Windows Haven’t Let in Any Wind for 15 Years Ever wondered why your car’s decade-old door/window rubber seals stay crack-proof and leak-free, while new wiper blades wear out and squeak quickly? The secret lies in materials: factory seals use EPDM rubber, while wipers are mostly natural rubber or neoprene, which age easily under ozone and sunlight. Known as durable long-life rubber, EPDM has been widely used since the 1960s with an annual global demand over 1.5 million tons. It tolerates temperatures from -50°C to 150°C and resists sun cracking for up to 20 years. This article covers EPDM’s wide industrial sealing applications and its unsuitable usage scenarios. Molecular Code: Why Is EPDM Naturally Resistant to Aging? It is composed of three monomers working together: Ethylene + Propylene: These form a highly saturated hydrocarbon backbone. Saturation means the material is “unlikely to cause trouble,” so ozone, UV rays, and oxygen do not affect it. Non-conjugated diene (commonly ENB): Added in small amounts (2%–9% by mass), it provides several cross-linkable “anchors” on the main chain, facilitating vulcanization and shaping. The main chain of ordinary natural rubber contains many double bonds, which act like “openings” that ozone can easily cut through. The main chain of EPDM is almost entirely saturated, making it 5 to 10 times more durable than general-purpose rubber.   III. Hardcore Performance: Just How Durable Is It? Excellent Resistance toAging Outdoor Service Life: Over 20 years. Ozone Resistance: Tested per ASTM D1149, shows no cracking at 50 pphm ozone. Elasticity Acrossa Wide Temperature Range Conditions Temperature Long-term use -50°C to +150°C Short-term heat resistance (for several hours in air) ≤175℃  (For temperatures exceeding this limit, use SIR or FPM) Embrittlement temperature Approx. -60°C (remains flexible)   Excellent electricalinsulation properties Volume resistivity can reach 10¹⁵ Ω·cm, making it one of the top choices for high-voltage cable insulation. Good abrasion resistance, though not the best EPDM offers better abrasion resistance than silicone rubber and most thermoplastic elastomers, but is inferior to NR and SBR. Therefore, it is not used in tire treads, but it is more than adequate for sealing strips and gaskets. Key Parameters of EPDM Performance Typical values Notes Density (g/cm³) 0.85～0.87 Unfilled Hardness (Shore A) 30～95 Adjustable Tensile Strength (MPa) 7～21 Can exceed 20 after reinforcement Elongation at Break (%) 100～600 High-resilience formulation: 800% Compression Set (%) 15～60 Peroxide curing as low as 15% Resistance to Mineral Oil/Fuel Oil Poor Critical flaw EPDM vs. Other Rubbers Performance EPDM SIR CR NBR Ozone Resistance / Weather Resistance ★★★★★ ★★★★ ★★★ ★ Long-Term Heat Resistance (°C) 150 200 100 120 Low-Temperature Flexibility ★★★★★ ★★★★ ★★★ ★★★ Resistance to Mineral Oils / Fuels ★ ★★ ★★★ ★★★★★ Price / Cost Medium High Medium Medium Typical Applications Sealing Strips/ Roof Waterproofing High-Temperature Gaskets Oil-Resistant Hoses Oil Seals, Fuel Lines   Where Is EPDM Used? Automotive (top market): Door/window/sunroof seals, coolant hoses, brake diaphragms. Each car consumes 8–12kg EPDM. EVs need more EPDM for battery seals, cooling pipes and high-voltage cables. Construction waterproofing: Roof sheets for airports, stadiums and malls, with a 25-year service warranty. Cables: Insulation for mining, nuclear and underground urban power cables. Industrial parts: Hydraulic seals, pump/valve diaphragms, steam hoses. New sectors: Athletic tracks, playground flooring, TPV raw materials. Pitfalls to Avoid: These Three Mistakes That 90% of People Make When Choosing EPDM 1.EPDM contact with mineral oil/fuel Result: Swell, soften & lose strength fast, cause leakage. Solution: Use NBR or FKM instead. 2.Sustained temp over 150°C / short spike over 175°C Result: Harden, crack, seal failure. Solution: SIR/FPM for constant >150°C service. 3.Mismatch with specific adhesives & chemicals Result: Bond separation, tackiness, material degradation. Solution: Run compatibility tests prior to application. VII. The Market and the Future: An Industry Approaching $10 Billion Year Global Consumption/Market Size Note 2023 Approx. 1.5 million metric tons Actual figures for the past three years 2030 1.8–1.9 million metric tons Annual growth rate of approximately 3.5% 2025(Market Size) Approx. $3.3 billion Conservative forecast 2035 (Optimistic) $8.4 billion Requires a growth rate of 6–7%, driven by electric vehicles and green buildings Regional Landscape: The Asia-Pacific region accounts for more than half of the global market, with China being the largest single market. In Europe, high-end EPDM sheet growth is accelerating due to building energy efficiency regulations. New Trends: In 2024, Dow Chemical launched a bio-based EPDM with a carbon footprint reduced by more than 40%. Sealing for electric vehicle battery packs and liquid-cooling piping have emerged as new growth areas. VIII. Conclusion: Choose the Right Material to Save Millions in Maintenance Costs No universal rubber，only the right one works. EPDM boasts outstanding weather resistance and wide-temperature elasticity, vital for auto seals, construction waterproofing and cable insulation. But it poorly resists oil and high heat, and improper use shortens product service life greatly. That solid car door closing sound and elastic playground tracks all rely on durable EPDM.

Ⅰ.What Is Post-Curing? In the production workshop, the process of heating, pressurizing, and shaping the finished product in a mold is called “first-stage curing” (also known as primary curing or initial curing). “Secondary vulcanization” (commonly referred to in the workshop as “second-stage vulcanization” or “post-cure”) refers to the process of neatly stacking rubber products that have already been demolded and shaped into a large industrial oven equipped with forced-circulation hot air, and continuing to bake them at atmospheric pressure for several hours at a specific temperature (typically 150–200°C). Ⅱ.Which Rubbers Require Secondary Vulcanization? Not all rubbers require secondary vulcanization. Common types such as natural rubber (NR), styrene-butadiene rubber (SBR), and butadiene rubber (BR) are generally fully cured after the initial vulcanization stage in the mold and are shipped directly from the factory. Those requiring secondary vulcanization are often “high-end specialty rubbers” that are expensive, subject to extremely strict performance requirements, or made with special vulcanizing agents:   Ⅱ.Which Rubbers Require Secondary Vulcanization? Not all rubbers require secondary vulcanization. Common types such as natural rubber (NR), styrene-butadiene rubber (SBR), and butadiene rubber (BR) are generally fully cured after the initial vulcanization stage in the mold and are shipped directly from the factory. Those requiring secondary vulcanization are often “high-end specialty rubbers” that are expensive, subject to extremely strict performance requirements, or made with special vulcanizing agents: 1.Silicone Rubber (MVQ / Silicone) — Over 95% require secondary vulcanization Reason: During compression molding or injection molding, silicone rubber uses peroxide-based curing agents (such as Di-25, Di-24, and odorless Di-25 curing agents). After these curing agents complete their reaction in the mold, they produce large amounts of acidic byproducts and volatile substances. Unless these are removed through a secondary curing process in an oven, silicone products will become brittle, yellow, or even develop a white bloom on the surface after just a few days. 2.Fluorocarbon Rubber (FKM / Viton) — 100% mandatory Reason: Fluorocarbon rubber reacts relatively slowly. During the brief few minutes spent in the mold (the first stage of curing), it actually forms only about 70% of its chemical cross-linking network. The remaining 30% must be transferred to a high-end oven set at 200–230°C and thoroughly cured for 8 to 24 hours to fully transform into its ultimate “oil- and heat-resistant” state. 3.Acrylate Rubber (ACM) and Hydrogenated Nitrile Rubber (HNBR) Reason: These two types of rubber are commonly used in high-end automotive oil seals and engine gaskets. Similar to fluorocarbon rubber, their reactions within the mold rarely reach full saturation. To achieve extremely low compression set, they must undergo secondary post-curing in an oven. 4.Automotive interior rubber parts with ultra-low odor and low VOC requirements (e.g., EPDM pedal covers, gaskets) Reason: Automakers enforce extremely strict standards for in-cabin air quality (odor testing per VDA 270). Ordinary EPDM products retain pungent amine and mercaptan odors after vulcanization, so they must be placed in an oven where high-intensity hot air is used to “squeeze out and bake away” the odors in a single pass. III. What Are the Core Benefits of Secondary Vulcanization? Given that it is labor-intensive and energy-consuming, secondary vulcanization must offer four irreplaceable, miraculous benefits:   The Four Core Benefits of Secondary Vulcanization 1.Fills the cross-linking network (eliminates under-vulcanization, doubling rebound and tensile strength) 2.Evaporates small molecules (removes residual cross-linking agents through heating, completely eliminating odors and white bloom) 3.Eliminating Internal Stress (Prevents later issues such as curling edges, distortion, and deformation) 4.Enhancing Durability (Maximizing resistance to pressure changes at high and low temperatures)   1.Making the Cross-Linked Network More Dense: Truly “Baking” the Rubber Through Many specialty rubbers are in a “half-baked” or “barely passable” state after the first stage of compression molding. Secondary vulcanization is like placing rice in a rice cooker for the final “steaming” process. Effect: It allows unreacted molecular chains within the rubber to continue linking together, exponentially increasing the cross-linking density. The resulting cured rubber experiences a qualitative leap in tear strength, tensile strength, and resilience. 2.Eliminate low-molecular-weight volatiles: Purify the product, eliminate odors, and remove bloom Toxins and odors generated by curing agents inside the mold are forcibly vaporized and extracted by the high-temperature hot air in the oven. Effect: Completely removes the fishy, kerosene, and pungent VOC odors from new products; simultaneously, it prevents curing agent residues from migrating to the surface, thoroughly eliminating the problem of “blooming” or “whitening” on the surface. For products such as medical-grade silicone and baby pacifiers, secondary vulcanization is a mandatory requirement for obtaining food-grade certification (FDA). 3.Stabilizing Product Dimensions: Eliminating “Trapped Internal Stress” When rubber compound is forced into the mold under high pressure, its molecular chains accumulate “internal stress” from being constrained. If shipped directly from the factory, the products will gradually shrink, deform, and warp over time. Effect: The high temperature in the oven allows the molecular chains to relax freely, releasing all the pent-up tension (eliminating internal stress). As a result, the finished products maintain extremely stable dimensions and will not lose their shape no matter how they are positioned. 4.Quality Enhancement: Pushing Compression Set (Creep Resistance) to the Limit High-end oil seals and O-rings, in particular, are most vulnerable to failing to rebound after being compressed. Effect: Secondary vulcanization creates a seamless chemical network, reducing the high- and low-temperature compression set of EPDM, fluorocarbon rubber, and hydrogenated nitrile rubber to half or even one-third of their original values. This not only extends the service life of the seals but also prevents premature oil and gas leaks.

Among after-sales faults of hydraulic machinery, auto parts, and general equipment, oil leakage of rubber seals ranks the most frequent issue. Most customers initially attribute seal oil leaks to manufacturing defects of molds, including insufficient mold precision, dimensional tolerance errors, and flash blemishes. Nevertheless, based on years of supporting experience in sealing production for hydraulics, automotive, and industrial equipment, plus review of tens of thousands of after-sales leakage cases from rubber manufacturers, over 90% of seal oil leak failures root in improper rubber compound selection, while less than 10% stem from mold accuracy problems. Field practices verify that with identical molds, assembly structures, and operating conditions of equipment, simply switching to application-specific rubber compounds can eliminate oil leakage and extend the seal service life by 3 to 5 times. Ⅰ.Core Principle: Seal failure originates primarily from material compatibility rather than mold dimensional accuracy. The core sealing principle of rubber seals lies in the elastic deformation of rubber compounds: the material fills between mating metal surfaces, providing steady, uniform contact pressure to seal against oil, water, and gas leakage. Molds are designed to control product dimension, appearance, and tolerance compliance, whereas the inherent properties of rubber compounds govern seal stability under actual working conditions. Even with zero-tolerance, high-precision, and flash-free molds, persistent oil leakage will occur if the rubber formulation mismatches service requirements. Four major failure modes are listed below: High-temperature softening failure Standard rubber grades have inferior heat resistance. As equipment temperature rises, seals rapidly soften and creep, resulting in reduced structural support and a sharp decline in sealing contact pressure. Clearances can no longer be filled, leading to oil seepage and dripping. Low-temperature elasticity failure In cold environments, mismatched rubber hardens and embrittles with a sharp rise in elastic modulus. It loses conformability and cannot follow equipment vibration and pressure fluctuation to cling to mating surfaces, creating gaps and oil leaks. Medium-induced swelling/shrinkage failure Industrial lubricants contain chemical additives, including antioxidants, EP additives, and anticorrosives, rather than pure base oil. Incompatible rubber will swell or shrink drastically, crack or pulverize upon fluid contact, completely losing dimensional accuracy and triggering leakage. Long-term permanent compression set failure. Low-grade or mismatched rubber features high permanent compression set. After prolonged compressive loading, the seal fails to rebound and turns rigid, becoming the primary culprit of gradual oil leakage during long-term equipment operation. After-sales statistics indicate that 82% of oil leakage issues can be fully fixed simply by switching to application-specific rubber without mold revision or assembly modification. Ⅱ.Core Industry Comparison Table: Standard Selection of Specific Rubber Compounds for Various Oil Media Components, pH values, and additive formulations vary drastically among different industrial oils, so no single all-purpose oil-resistant rubber compound exists. Blind adoption of ordinary black general-purpose sealing rings accounts for 90% of material selection errors. In accordance with national industry standards and mass production specifications, below are the precise material selection comparison table and common pitfalls to avoid: Applicable Oil Type Optimal Rubber Grade Key Performance Requirements Common Selection Mistakes & Failure Consequences Conventional Mineral Hydraulic Oil NBR Mineral oil resistance, compression set ≤15%, service temperature: -30℃~100℃ Wrong selection of NR/SBR; severe swelling & cracking after oil immersion leading to rapid oil leakage High-Temp Engine Oil ACM Resistance to hot engine oil & oil oxidation, long-term stable at 120℃ Ordinary NBR misused; fast hardening & cracking under high temperature with total seal failure EP Additive Containing Gear Oil FKM Excellent chemical & EP additive resistance, stable oil resistance NBR misused; chemical erosion from gear oil additives causes material delamination and persistent leakage DOT Series Brake Fluid EPDM Resistance to polar solvents & brake fluid corrosion NBR/FKM misused; excessive swelling resulting in complete loss of sealing performance Lubricating Oil above 150℃ FVMQ Balanced high/low temp resistance, lube resistance and stable elasticity Conventional FKM misused; insufficient low-temp elasticity causes continuous oil seepage Core Selection Rule: Confirm 4 working parameters prior to custom seal ordering; reject empirical selection by appearance. Ⅲ.Objective Conclusion: Molds are not the root cause for oil leakage defects. We never deny the importance of mold precision. Mold defects such as misplaced parting lines, excessive flash, out-of-tolerance dimensions, and demolding deformation can indeed trigger short-term poor sealing and oil leakage. However, statistics from tens of thousands of failure cases show that less than 10% of oil leakage issues stem directly from inadequate mold manufacturing precision. A common industry misconception persists: when equipment leaks oil, companies blindly develop new molds, revise mold specifications, or switch mold suppliers, consuming substantial time and cost yet failing to resolve the trouble. The root cause lies in treating symptoms instead of the source: no matter how precise the mold dimension is, sealing performance becomes meaningless if the rubber compound fails to match actual service conditions. Numerous clients who spent repeated efforts on mold modification with no improvement have permanently eliminated oil leakage simply by switching to application-specific rubber grades, with no mold alteration or equipment adjustment required. Ⅳ.3-Step Operation Rules: Eliminate Seal Ring Oil Leakage Step 1: Verify actual service conditions precisely and reject ambiguous material selection Specified parameters shall be finalized material selection; vague descriptions, including “ambient temperature, ordinary engine oil, and standard pressure” are not acceptable. Temperature: Confirm maximum operating temperature, minimum ambient temperature, and continuous high-temperature duration; Medium: Specify exact oil grade, presence of EP additives/corrosion inhibitors, and mixed contaminants; Application type: Differentiate static sealing, reciprocating sealing, and rotary dynamic sealing. Pressure: Clarify normal working pressure and instantaneous peak pressure. Step 2: Require suppliers to supply complete batch material test reports Qualified seal manufacturers enable full traceability for every batch of rubber compound. Core performance test data must be requested to avoid inferior blended rubber and shoddy substitution: Basic indicators: Rubber hardness, tensile strength, and elongation at break. Oil resistance indicators: Volume change rate and weight change rate after oil immersion. Durability indicators: Permanent compression set (key index for sealing service life). Environmental indicators: Test data from high & low temperature aging tests. Step 3: Conduct small-batch installation verification before mass production launch For severe working conditions, including high temperature, dynamic movement, and special oil media, prioritize trial production, bench testing, and field installation verification with small lots. Optimal industrial workflow: Test oil leakage by switching to a matching rubber compound first. Proceed with mold optimization evaluation only after verifying satisfactory performance, to eliminate unnecessary mold revisions and redundant cost waste. Ⅴ.Conclusion Core sealing principle for rubber seals: Molds control dimensional accuracy, while rubber compounds determine sealing service life. 90% of oil leakage failures originate from mismatched rubber material against service conditions rather than inadequate mold precision. With properly selected application-specific rubber, qualified mold dimensions, and standard installation, the oil-tight reliability and overall service life of sealing rings can be improved 3 to 5 times, drastically cutting after-sales breakdown rates, maintenance expenses, and equipment downtime losses. The professional and cost-effective industry standard for seal selection follows this order: check rubber compound first, then inspect mold quality.  

Rubber sealing rings are vital components in numerous industrial manufacturing fields. Their high-temperature resistance directly determines whether equipment suffers liquid or gas leakage, or even shutdown failures. It is crucial to select suitable rubber sealing rings in advance, rather than trying to fix problems after malfunctions occur. Technically, high temperature resistance is closely linked to the thermal stability of rubber molecular chains. For instance, the carbon-fluorine bond energy of fluororubber reaches 485 kJ/mol, significantly higher than the carbon-hydrogen bond energy of common rubber, which is around 410 kJ/mol. The silicon-oxygen bond energy of silicone rubber stands at approximately 443kJ/mol, surpassing that of ordinary organic polymers (about 346kJ/mol). Accordingly, they boast excellent heat resistance and will not decompose or melt under high temperatures.   PART 01 High-temperature Resistance Comparison of Sealing Ring Materials FKM Usable temperature range -20℃ to 200℃. Withstands 250℃ briefly and 300℃ momentarily. Features oil, acid, alkali, and aging resistance. Ideal for engines, chemical facilities, fuel systems, and high-temperature valves. VMQ Wide temperature tolerance, long-term service at -60℃ to 200℃. Excellent cold and heat resistance. Special formulas endure over 250℃ temporarily. Suitable for home appliances, medical, and electronic applications. FVMQ Outstanding heat resistance. Stable from -50℃ to 250℃. High-grade variants sustain peak temperature up to 300℃ instantly. EPDM Good heat resistance, temperature range -55℃ to 150℃. Excellent resistance to steam and hot water, widely used in heating pipelines and cooling systems. NBR Working temperature -20℃ to 100℃, maintains stable sealing performance within the range. Rapid aging occurs above 120℃, which is not applicable for continuous high-temperature service. PTFE & Flexible Graphite Non-traditional rubber materials with superior extreme high-temperature performance. Filled PTFE dynamic seal withstands up to 265℃. Metal-clad flexible graphite static seal resists temperature up to 650℃. Applied to ultra-high temperature static sealing in oil refining and high-temperature furnaces.   PART 02 High-temperature Application of Sealing Rings Rubber materials retain elasticity, sealing performance, and mechanical strength within specific temperature ranges, enabling long-term service. Certain types can endure short-term high temperatures. Two critical temperature thresholds apply: Minimum operating temperature: Rubber turns brittle, loses elasticity, and may crack below this value. Maximum operating temperature: Excess heat causes softening, oxidation, hardening, and permanent deformation, resulting in loss of resilience and bearing capacity. The rated temperature range differs from the actual working temperature. Material formula, manufacturing process, contact medium, and dynamic/static working conditions all affect performance. A comprehensive assessment is required to guarantee a reliable sealing effect.

I.Core Properties of Common Rubbers II.Differences and Applications of Common Rubbers Note: Practical rubber products often contain pigments, so color cannot be used as the sole basis for identification. The most reliable methods are: – Checking the material marking (e.g., markings on oil seals) – Consulting your supplier For simple identification, you can combine: – Oil resistance test (observe swelling after immersion) – Burning characteristics (e.g., CR is self-extinguishing) III.Advantages and Disadvantages of Common Rubbers Natural Rubber (NR) Main Advantages: Excellent elasticity, tensile strength, and tear resistance; good processability. Main Disadvantages: Poor resistance to oil, ozone, and heat aging; narrow operating temperature range. Styrene-Butadiene Rubber (SBR) Main Advantages: High abrasion resistance, heat resistance, low cost, and the highest production volume. Main Disadvantages: Slightly lower elasticity and cold resistance; poor resistance to oil. Butadiene Rubber (BR) Main Advantages: Outstanding elasticity, abrasion resistance, and cold resistance. Main Disadvantages: Poor tear resistance. Chloroprene Rubber (CR) Main Advantages: Good overall performance; resistant to oil, weathering, flame, and ozone aging. Main Disadvantages: High density, average low-temperature performance, and relatively expensive. Nitrile Rubber (NBR) Main Advantages: Excellent oil resistance (second only to fluorocarbon rubber, etc.), good abrasion resistance, and airtightness. Main Disadvantages: Poor cold resistance, ozone resistance, and electrical insulation. Ethylene Propylene Diene Monomer (EPDM) Main Advantages: Superior resistance to ozone, weathering, and aging; resistant to hot water and steam; good electrical insulation. Main Disadvantages: Poor oil resistance; slow vulcanization; poor self-adhesion. Butyl Rubber (IIR) Main Advantages: Best gas and water tightness; heat and aging resistance. Main Disadvantages: Poor tack, slow vulcanization, and poor oil resistance. Silicone Rubber (SI) Main Advantages: Widest temperature resistance range, non-toxic, insulating, and ozone-resistant. Main Disadvantages: Low mechanical strength, poor oil and solvent resistance, and high cost. Fluorocarbon Rubber (FKM) Main Advantages: High-temperature resistance, oil resistance, superior chemical resistance, and aging resistance. Main Disadvantages: Very expensive, poor processability, average cold resistance, and low elasticity. Chlorosulfonated Polyethylene (CSM) Main Advantages: Excellent abrasion resistance, weather resistance, ozone resistance, and good flame retardancy. Main Disadvantages: High cost, poor rebound, and compression set properties. IV. Quick Selection Guide Great elasticity → Choose Natural Rubber (NR) Great wear resistance & low cost → Choose Styrene-Butadiene Rubber (SBR) Oil resistance → Choose Nitrile Rubber (NBR) (general use) or Fluoro Rubber (FKM)(extreme conditions) Weather & aging resistance → Choose Ethylene Propylene Rubber (EPDM) Air & water tightness → Choose Butyl Rubber (IIR) Wide temperature resistance → Choose Silicone Rubber (SI) Super corrosion resistance → Choose Fluoro Rubber (FKM)