Soft Durometer FFKM: Why 60 Shore A Perfluoroelastomers Are Growing in Demand
Updated: Aug 19, 2026
Perfluoroelastomer, commonly known as FFKM, is typically selected for some of the most demanding sealing environments in industry. Its combination of exceptional chemical resistance and high-temperature performance makes FFKM a common choice for semiconductor equipment, chemical processing systems, pumps, valves, oil and gas equipment, and other applications involving aggressive process media.
While much of the FFKM market has traditionally centered around compounds in the 70 to 90 Shore A range, we are seeing increasing demand for soft durometer FFKM compounds. In particular, customers are looking for 60 Shore A FFKM materials that provide the chemical and temperature capabilities expected from a perfluoroelastomer while offering a softer, more conformable sealing material.
This has also resulted in customers evaluating alternatives to established materials such as Kalrez® 4079 and Kalrez® 8575. Canrez® CP60BK00 and its white counterpart, Canrez® CP60WH00, provide a 60 Shore A FFKM option for applications where chemical resistance, high-temperature performance, low compression set, and a softer sealing material are required.
What Is Soft Durometer FFKM?
Durometer is a measurement of material hardness. For elastomeric seals, Shore A is one of the most commonly used hardness scales. As the Shore A value decreases, the elastomer becomes softer and generally requires less force to deform.
A 60 Shore A FFKM is therefore noticeably softer than a typical 70, 75, 80, or 90 Shore A perfluoroelastomer.
This difference can be particularly important in static sealing applications. A softer elastomer can more readily conform to the mating surfaces of a seal assembly, allowing the material to accommodate small surface imperfections and establish sealing contact with less compressive force.
The Parker O-Ring Handbook similarly notes that softer sealing materials flow more readily into microscopic grooves and imperfections in mating surfaces, an attribute that can be particularly useful in lower-pressure sealing applications. Harder materials, by comparison, generally provide greater resistance to extrusion. This illustrates why durometer should be selected according to the mechanical requirements of the application rather than simply specifying the hardest available material.
Why Use a 60 Shore A FFKM?
The primary reason to select a softer FFKM is not simply that the material is more flexible. Lower hardness changes how the seal responds when compressed within the sealing interface.
Potential advantages of a 60 Shore A FFKM include:
- Lower sealing force: A softer compound can deform with less compressive force, which can be useful when the assembly provides limited clamping force.
- Improved conformity: The material can more readily conform to minor imperfections in mating surfaces.
- Low-pressure sealing: Softer elastomers can be advantageous where system pressure provides little additional force to energize the seal.
- Delicate components: Lower sealing forces may be beneficial when surrounding components cannot tolerate excessive loading.
- FFKM chemical resistance: The benefits of lower hardness can be combined with the broad chemical resistance associated with perfluoroelastomers.
- High-temperature capability: Properly formulated soft FFKM compounds can maintain performance at temperatures far beyond conventional elastomers.
Soft FFKM is not automatically the best choice for every application. Higher pressures, large extrusion gaps, or other demanding mechanical conditions may favor a harder compound or require additional seal design considerations.
Canrez® CP60BK00 60 Shore A FFKM
Canrez® CP60BK00 is a black, 60 Shore A general-purpose FFKM developed to provide broad chemical resistance and high-temperature performance at a substantially more accessible price point than many traditional perfluoroelastomers.
CP60BK00 provides near-universal chemical resistance while maintaining the elasticity and sealing characteristics expected from an FFKM.
CP60BK00 Features & Benefits
- 60 Shore A hardness
- Near-universal chemical resistance
- High-temperature resistance
- Low compression set
- Soft, conformable sealing characteristics
- Cost-effective alternative to premium FFKM compounds
CP60BK00 has a recommended service temperature range of -15°C to 260°C (5°F to 500°F) and can withstand short excursions outside of its normal operating range.
Canrez® CP60WH00 White FFKM
For applications where a black compound is undesirable, Canrez® CP60WH00 provides a white version of the 60 Shore A FFKM platform.
White FFKM compounds can be desirable in applications where color differentiation, visual inspection, cleanliness protocols, or equipment-specific material requirements make a non-black elastomer preferable.
CP60WH00 provides another option for engineers who need the benefits of a softer FFKM without using a traditional black compound.
Alternatives to Kalrez® 4079 and Kalrez® 8575
Kalrez® has been one of the most recognized names in perfluoroelastomer sealing for decades. Kalrez® 4079 and Kalrez® 8575 are consequently encountered in many existing equipment specifications, maintenance programs, and sealing applications.
However, specifying FFKM by brand or legacy compound alone can limit the alternatives available to engineers and maintenance teams.
We are increasingly working with customers interested in evaluating Canrez® CP60BK00 as an alternative to Kalrez® 4079 and Kalrez® 8575, particularly when they are looking for a softer 60 Shore A FFKM or want to reduce the cost associated with their existing perfluoroelastomer seals.
CP60BK00 should not be considered an automatic drop-in equivalent solely because the materials belong to the FFKM family. Different FFKM formulations can have meaningful differences in hardness, temperature capability, chemical resistance, compression set, and other physical properties.
Instead, the existing Kalrez® compound provides a useful starting point for evaluating the actual requirements of the application.
Questions should include:
- What chemicals contact the seal?
- What are the minimum and maximum operating temperatures?
- What pressure does the seal experience?
- Is the application static or dynamic?
- What is the extrusion gap?
- Is 60 Shore A appropriate for the existing gland?
- Are there regulatory, purity, or material certification requirements?
Once these conditions are understood, an alternative FFKM can be evaluated based on the application rather than the brand name printed on an existing specification.
FFKM Chemical Resistance
Chemical resistance is one of the primary reasons engineers move from FKM, EPDM, NBR, and other conventional elastomers to FFKM.
Perfluoroelastomers offer exceptionally broad resistance to aggressive process media. FFKM materials are commonly considered for environments involving:
- Acids
- Bases
- Solvents
- Hydrocarbons
- Aggressive process chemicals
- High-temperature fluids
- Harsh cleaning chemistries
This broad resistance can make a general-purpose FFKM such as CP60BK00 useful when a system encounters multiple chemicals or when process conditions make conventional elastomers difficult to use reliably.
Material compatibility should still be evaluated against the specific chemicals, concentrations, temperatures, and exposure conditions present in the application.
FFKM vs. FKM
FKM provides excellent performance in many oils, fuels, hydrocarbons, and industrial chemicals and remains one of the most versatile high-performance sealing materials available.
FFKM extends chemical resistance considerably further.
For systems where FKM experiences excessive swelling, hardening, softening, chemical attack, or premature compression set, moving to an FFKM may significantly increase seal life.
The higher initial cost of FFKM can therefore be justified when seal replacement requires:
- Equipment shutdown
- Process interruption
- System cleaning
- Lost production
- Significant maintenance labor
- Disposal of contaminated product
In these situations, seal price represents only a small portion of the true cost of a sealing failure.
For a deeper explanation on the differences between FKM and FFKM, see our comparison page.
Common Applications for Soft FFKM
Semiconductor Equipment
Semiconductor manufacturing exposes seals to aggressive process chemicals, elevated temperatures, and environments where equipment reliability is critical. FFKM is widely used throughout semiconductor processing equipment for these reasons.
Chemical Processing
Chemical plants frequently require one sealing material to withstand acids, solvents, bases, and other aggressive media. The broad chemical resistance of FFKM makes it particularly valuable for these environments.
Pumps and Valves
O-rings and other seals used in pumps and valves may need to conform to sealing surfaces while resisting aggressive process fluids. A softer 60 Shore A FFKM can be particularly useful where lower sealing forces are desirable.
Solvent Processing
Many conventional elastomers can swell, soften, or otherwise deteriorate when exposed to aggressive solvents. FFKM provides a substantially broader chemical resistance profile for demanding solvent applications.
Oil & Gas
Oil and gas equipment can expose seals to combinations of hydrocarbons, chemicals, pressure, and temperature. FFKM may be considered where conventional elastomers cannot provide adequate service life.
Harsh Chemical Applications
Processes involving multiple aggressive chemicals can make material selection particularly difficult. General-purpose FFKM compounds provide one of the broadest chemical compatibility ranges available among elastomeric sealing materials.
When Should You Consider Switching to FFKM?
Not every application requires a perfluoroelastomer.
EPDM, FKM, silicone, HNBR, and other elastomers can provide excellent service when properly matched to the operating environment. FFKM becomes particularly attractive when conventional materials repeatedly fail or when the consequences of failure justify a higher-performance material.
Consider evaluating FFKM when you are experiencing:
- Chemical degradation
- Excessive seal swelling
- Seal hardening
- Loss of elasticity
- Compression set
- Frequent O-ring replacement
- Unplanned equipment downtime
For applications already using FFKM, evaluating alternative compounds may also provide opportunities to improve sealing characteristics or reduce material costs.
Is a Softer FFKM Right for Your Application?
The growing demand for 60 Shore A FFKM reflects an important reality in seal engineering: harder is not always better.
A softer seal can provide advantages when the application requires greater conformity, reduced sealing force, or improved response under low-pressure conditions. At the same time, the seal must still provide sufficient mechanical strength and extrusion resistance for the operating environment.
Canrez® CP60BK00 and CP60WH00 provide engineers with 60 Shore A FFKM options designed to combine these softer sealing characteristics with the broad chemical resistance and high-temperature capability expected from a perfluoroelastomer.
For companies currently using Kalrez® 4079, Kalrez® 8575, or another branded FFKM compounds, the application can be reviewed to determine whether a Canrez® alternative may provide the required performance at a substantially lower material cost.
Canrez® FFKM Sealing Solutions from Canyon Components
Canyon Components supplies Canrez® FFKM O-rings, gaskets, and custom sealing components for demanding applications across semiconductor, chemical processing, oil and gas, pharmaceutical, industrial, and other high-performance industries.
Canrez® CP60BK00 provides a black 60 Shore A general-purpose FFKM option, while CP60WH00 provides a white alternative for applications requiring a non-black compound.
Beyond simply matching an existing part number, our team can evaluate the application conditions, chemical exposure, temperature, pressure, seal geometry, and existing material to help identify an appropriate FFKM compound.
