Teflon® Encapsulated O-Rings: Replacing PFAS FKM

Teflon® Encapsulated O-Rings: Replacing PFAS: The sealing industry is now facing regulatory challenges with fluoroelastomer (FKM) materials, especially since these materials may be classified as PFAS (Per- and Polyfluoroalkyl Substances). In this context, this white paper reviews the chemical makeup, properties, pros, and cons of both fluoroelastomers (FKM) and M-COR’s new EPDM compound. Additionally, it provides a comparative analysis to evaluate the possibility of replacing fluoroelastomer (FKM) cores with M-COR EPDM in Teflon® encapsulated O-rings.

A Viable Solution to Eliminate PFAS in FKM Encapsulated O-Rings

M-COR Engineering has teamed up with supply partners to create a PFAS-free EPDM compound for Teflon® Encapsulated O-Rings core material. This new compound closely matches the mechanical properties of fluoroelastomers (FKM). Additionally, it offers a viable replacement in up to 85% of applications where FKM Teflon Encapsulated O-Rings are used. As a result, this development provides a viable alternative for many sealing needs while also addressing  PFAS free environmental concerns.

Teflon® Encapsulated O-Rings: Replacing PFAS: Innovating for Sustainability

M-Cor Inc., we strongly believe that sustainable business practices are essential not only for achieving long-term success but also for creating a positive impact. Furthermore, we are fully dedicated to minimizing our environmental footprint, while also promoting social responsibility and, at the same time, ensuring economic viability. Ultimately, our goal is to deliver high-quality products and services to our customers in a manner that aligns with these values.

Teflon® encapsulated O-rings are critical components in sealing applications because they combine the elasticity of an elastomer core with the chemical resistance of a Teflon (FEP or PFA) sheath. However, fluoroelastomers (FKM), which are commonly used as core materials, are now under scrutiny due to environmental concerns associated with PFAS. As a result, it has become necessary to explore alternative materials, such as specially formulated EPDM, that can meet performance requirements while also mitigating environmental risks.

Chemical Makeup

Fluoroelastomers (FKM):

• Composition: FKM consists of copolymers of hexafluoropropylene, vinylidene fluoride, and other fluorinated monomers. Additionally, these monomers are classified as PFAS.
• Structure: Its high fluorine content not only provides excellent chemical resistance but also offers significant thermal stability.
• Environmental Concern: FKM, as a type of PFAS, is persistent in the environment, raising potential health risks over time.

EPDM (Ethylene Propylene Diene Monomer):

• Composition: EPDM is a terpolymer made from ethylene, propylene, and a diene component, such as ethylidene norbornene. Furthermore, this composition supports its versatile properties.
• Structure: It features a saturated backbone with unsaturated side chains, allowing for sulfur vulcanization. As a result, it maintains flexibility and resilience.
• Environmental Profile: Unlike FKM, EPDM does not fall under PFAS classification. Therefore, it is considered more environmentally friendly.

Pros and Cons

Fluoroelastomers (FKM)
Pros:

• They offer exceptional chemical resistance, especially to hydrocarbons, acids, and alkalis.
• Additionally, they can tolerate high temperatures, up to 200°C or even higher in some cases.
• Furthermore, they have low permeability to gases, which enhances their sealing performance.

Cons:

• However, there are environmental concerns due to their classification as PFAS, making them persistent in the environment.
• They also come with higher material and processing costs, adding to their overall expense.
• Moreover, they have limited resistance to certain chemicals like ketones, amines, and steam, which can restrict their applications.

M-COR EPDM
Pros:

• M-COR EPDM excels in its resistance to weathering, ozone, and UV exposure, making it durable in outdoor conditions.
• It also provides good chemical resistance to polar solvents, acids, and alkalis, which broadens its range of applications.
• Additionally, it operates across a wide temperature range, from -50°C to 150°C, offering flexibility in various environments.
• Not only is it cost-effective and readily available, but it is also an environmentally safer alternative to PFAS-based materials.

Cons:

• However, it has poor resistance to hydrocarbons and oils, limiting its use in some industrial environments.
• Its high-temperature tolerance is also lower compared to fluoroelastomers, which can be a disadvantage in certain applications.
• Additionally, it has higher gas permeability, which may affect its performance in specific sealing applications.

Comparative Analysis

Physical Properties: Click Here

Discussion

While fluoroelastomers offer superior chemical and temperature resistance, their environmental impact and regulatory challenges, however, cannot be overlooked. As a result, EPDM presents a viable alternative, especially for applications where resistance to hydrocarbons and oils is not critical. Furthermore, its excellent resistance to weathering and polar substances, combined with a broad temperature range and lower cost, makes it suitable for many sealing applications.

In the case of Teflon® encapsulated O-rings, the Teflon sheath provides a high degree of chemical resistance, which may potentially compensate for EPDM’s shortcomings in hydrocarbon resistance. Consequently, this encapsulation could allow EPDM cores to perform adequately in environments that were previously dominated by fluoroelastomers.

Considering both environmental concerns and the increasing regulatory pressures, as well as the specific performance requirements of various industries, EPDM emerges as a highly promising alternative to fluoroelastomer cores in Teflon encapsulated O-rings. Not only do its favorable properties make it a strong contender, but when combined with the protective Teflon sheath, it can effectively meet the diverse demands of many sealing applications. Additionally, this combination offers significant environmental and economic benefits, making EPDM an attractive solution for companies looking to balance performance with sustainability.

Recommendations:

1. Application Assessment: It is essential to evaluate the specific chemical and temperature requirements of each application to accurately determine EPDM’s suitability. Additionally, this assessment ensures that the material will perform as expected in different environments.
2. Testing: Furthermore, conducting thorough testing of EPDM-core Teflon encapsulated O-rings in real-world conditions is crucial. This step will validate the material’s performance and confirm its ability to meet application-specific needs.
3. Regulatory Compliance: As regulations regarding PFAS continue to evolve, it is important to stay informed and proactively adapt materials to ensure compliance. By doing so, companies can mitigate risks and avoid potential regulatory issues.
4. Environmental Responsibility: Prioritizing materials with a lower environmental impact not only supports sustainability goals but also positions companies as leaders in environmental stewardship. Moreover, this approach aligns with growing market demand for eco-friendly solutions.

References

1. ASTM D1418-17a Standard Practice for Rubber and Rubber Latices—Nomenclature
2. EPA PFAS Action Plan