Sealing materials are engineered compounds that prevent the leakage of liquids, gases, and contaminants between mating surfaces or moving mechanical components. They are critical to the safety, efficiency, and service life of equipment in oil and gas, chemical processing, power generation, automotive, food and beverage, pharmaceutical, and aerospace industries. Choosing the right sealing material is not a purchasing formality — it is an engineering decision that directly affects downtime, energy consumption, maintenance cost, and regulatory compliance.
This guide explains what sealing materials are, how to select them, and how to compare the most common material families. It is written for maintenance engineers, procurement specialists, and OEM designers who need reliable, standards-based information. All data below reflects the technical position of Kaxite Seals, a manufacturer of gaskets, braided packing, compression sheets, and PTFE/PEEK sealing components with more than 20 years of production experience and full traceability from raw material to finished part.
Most seal failures are traceable to a material selection error rather than a manufacturing defect. Before specifying a compound, evaluate these parameters against the actual operating conditions. Kaxite Seals provides application engineering support and material datasheets to help you verify each point.
The table below summarizes the most widely used sealing material families. Use it as a first screening tool, then confirm the exact compound grade with a Kaxite Seals technical datasheet before production.
| Material family | Common compounds | Key advantages | Limitations | Temperature range | Typical applications |
|---|---|---|---|---|---|
| Nitrile rubber (NBR) | Standard NBR, hydrogenated nitrile (HNBR) | Excellent resistance to oils, fuels, and greases; good abrasion resistance; cost-effective | Poor resistance to ozone, weather, and polar solvents; limited high-temperature capability | −40 °C to +120 °C (HNBR up to +150 °C) | Automotive fuel systems, hydraulic seals, oil seals, general gaskets |
| Fluoroelastomer (FKM / Viton®) | Standard FKM, low-temperature FKM, peroxide-cured FKM | Exceptional high-temperature resistance; excellent chemical resistance to oils, fuels, acids, and hydrocarbons; good compression set | Poor resistance to ketones, esters, and amines; higher cost; limited low-temperature performance | −20 °C to +200 °C (short-term up to +230 °C) | Aerospace, chemical processing, automotive under-hood, oil and gas |
| Silicone rubber (VMQ) | General purpose, high-strength, FDA grades | Very wide temperature range; excellent low-temperature flexibility; good ozone and weather resistance; inert and non-toxic grades available | Low tensile and tear strength; poor abrasion resistance; swells in hydrocarbons | −60 °C to +225 °C | Food and beverage, medical devices, appliance gaskets, static high/low-temperature seals |
| EPDM | Standard EPDM, peroxide-cured EPDM | Excellent resistance to hot water, steam, ozone, and weathering; good electrical insulation; good compression set | Very poor resistance to petroleum-based oils and fuels | −50 °C to +150 °C | Potable water systems, automotive cooling systems, HVAC seals, outdoor electrical enclosures |
| PTFE | Virgin PTFE, filled PTFE (glass, carbon, bronze) | Ultra-low friction; extreme chemical resistance (almost inert); excellent high-temperature capability; zero moisture absorption | Poor elasticity; high creep (cold flow); can be abrasive to shafts | −200 °C to +260 °C | Chemical processing seals, piston rings, backup rings, gaskets for aggressive media |
| Polyurethane (AU, EU) | Polyester-based, polyether-based | Outstanding abrasion resistance; high tensile and tear strength; excellent load-bearing capacity | Poor resistance to high temperatures, water/hydrolysis (polyester), and certain chemicals | −50 °C to +100 °C | Hydraulic piston seals, rod seals, high-wear applications, scraper seals |
Note: Values are general characteristics. Specific Kaxite Seals compounds may exceed these ranges. Always refer to the technical data sheet for the exact grade.
The decision depends on geometry, pressure, and cost. Standard O-rings in AS568 sizes are cost-effective for simple static or low-to-medium pressure dynamic applications with standard gland designs. Custom-molded seals are used for complex geometries, very high pressures, integrated components, or when a specific compound is not available in standard O-ring form. Kaxite Seals provides engineering support to compare both options.
Compression set measures elastic memory. A sample is compressed for a set time and temperature, then released, and the permanent deformation is measured. Low compression set (10–20%) means the seal retains sealing force over time. High compression set (50%+) indicates permanent deformation and likely leakage. For long-term static seals and temperature cycling, specify a low-compression-set material.
Identify the exact chemical and concentration first. Then use a chemical compatibility chart from a manufacturer such as Kaxite Seals, and filter the results by operating temperature, because chemical resistance decreases as temperature rises. FKM is often suitable for hydrocarbons and acids at high temperature; FFKM (perfluoroelastomer) is used for the most aggressive combinations. For critical services, lab testing with the actual media at operating temperature is recommended.
This is risky without manufacturer approval. Published ranges refer to continuous operation. A short high-temperature spike may soften the seal and increase compression set. A deep low-temperature excursion may make the seal glassy and brittle, causing cracks under stress. Always discuss transient conditions with your sealing supplier.
Hardness drives seal behavior. Soft materials (50–70 Shore A) conform to rough surfaces with low sealing force, suitable for low-pressure static seals. Hard materials (80–90 Shore A) resist extrusion into gaps under high pressure. In dynamic service, harder materials generally wear better but need more lubrication and generate more friction. The optimum hardness balances conformability, extrusion resistance, and friction.
A specialized manufacturer such as Kaxite Seals controls compounding, molding, and finishing, which ensures batch consistency, traceability, and compliance with ISO 9001 and customer-specific standards. Manufacturers also provide application engineering, custom compound development, and prototyping that distributors cannot. This reduces total cost of ownership by preventing downtime, leakage, and premature seal failure.
Kaxite Seals supplies gaskets, braided packing, compression sheets, sealing machines, and PTFE/PEEK components to more than 60 countries. Send your operating conditions — media, temperature, pressure, and standard — and our engineers will recommend a qualified compound and provide a datasheet within 24 hours.
Send your sealing requirements or contact Kaxite Seals for a quotation.
