FFKM vs. FKM

Attribute	FFKM	FKM
Chemical Resistance	Excellent	Good
Temperature Resistance	Up to 327°C	Up to 204°C
Compression Set	Low	Medium
Tensile Strength	High	Medium
Elongation at Break	Low	Medium
Hardness	Shore A 70-90	Shore A 70-90
Cost	Higher	Lower

Introduction

When it comes to choosing the right material for various industrial applications, it is essential to consider the specific requirements and conditions. Two commonly used elastomers in the industry are FFKM (Perfluoroelastomer) and FKM (Fluoroelastomer). While both materials offer excellent resistance to chemicals and high temperatures, they have distinct attributes that make them suitable for different applications. In this article, we will compare the attributes of FFKM and FKM, highlighting their differences and applications.

Chemical Resistance

One of the primary reasons for choosing FFKM or FKM is their exceptional chemical resistance. FFKM, being a perfluorinated elastomer, exhibits superior resistance to a wide range of aggressive chemicals, including acids, bases, solvents, and even some reactive gases. This makes FFKM an ideal choice for applications in the chemical processing industry, where exposure to harsh chemicals is common.

On the other hand, FKM, although not as chemically resistant as FFKM, still offers excellent resistance to a broad spectrum of chemicals. It can withstand exposure to oils, fuels, hydraulic fluids, and many organic solvents. FKM is commonly used in automotive applications, such as seals and gaskets, where resistance to oils and fuels is crucial.

Temperature Resistance

Both FFKM and FKM exhibit remarkable temperature resistance, allowing them to perform in extreme environments. FFKM, with its perfluorinated structure, can withstand temperatures ranging from -20°C to over 300°C (-4°F to 572°F). This exceptional heat resistance makes FFKM suitable for applications in aerospace, semiconductor, and oil and gas industries, where exposure to high temperatures is common.

FKM, on the other hand, has a slightly lower temperature resistance compared to FFKM. It can typically handle temperatures ranging from -20°C to 200°C (-4°F to 392°F). Despite the lower upper temperature limit, FKM is still widely used in various industries, including automotive, chemical, and food processing, where the operating temperatures are within its range.

Compression Set and Elasticity

Compression set refers to the ability of an elastomer to recover its original shape after being subjected to compression. FFKM exhibits excellent compression set resistance, meaning it can maintain its shape and sealing properties even after prolonged compression. This attribute makes FFKM suitable for applications where long-term sealing performance is critical, such as in the pharmaceutical and food industries.

FKM, while not as resistant to compression set as FFKM, still offers good elasticity and can recover its shape after compression. It is commonly used in applications where moderate compression set resistance is sufficient, such as in automotive engines and hydraulic systems.

Physical Properties

FFKM and FKM have different physical properties that contribute to their suitability for specific applications. FFKM has a higher density compared to FKM, which results in improved resistance to permeation and better sealing capabilities. This makes FFKM an excellent choice for applications where maintaining a hermetic seal is crucial, such as in the semiconductor and pharmaceutical industries.

FKM, on the other hand, has a lower density compared to FFKM, which can be advantageous in applications where weight reduction is a priority. Additionally, FKM has good tear resistance and tensile strength, making it suitable for applications that require durability and resistance to mechanical stress, such as in automotive and industrial sealing applications.

Cost Considerations

Cost is an important factor to consider when selecting a material for any application. FFKM, being a specialized and high-performance elastomer, is generally more expensive compared to FKM. The higher cost of FFKM is justified by its exceptional chemical resistance, temperature resistance, and compression set resistance, which make it indispensable in certain industries.

FKM, on the other hand, offers a good balance between performance and cost. It provides excellent chemical resistance, temperature resistance, and elasticity at a more affordable price point. This makes FKM a popular choice for a wide range of applications where the extreme properties of FFKM are not required.

Conclusion

In summary, FFKM and FKM are both excellent elastomers with unique attributes that make them suitable for different applications. FFKM offers superior chemical resistance, higher temperature resistance, and better compression set resistance, making it ideal for industries such as chemical processing, aerospace, and oil and gas. FKM, on the other hand, provides good chemical resistance, moderate temperature resistance, and elasticity at a more affordable cost, making it a popular choice in automotive, food processing, and various other industries. When selecting between FFKM and FKM, it is crucial to consider the specific requirements of the application and choose the material that best meets those needs.