Seal Wear Goodbye How Perfluoroelastomers Resist Aggressive Application Conditions

| Editor: Tobias Hüser

As for any complex process, the devil is in the detail, and, in manufacturing, there are few exceptions. Here is where a system's smallest components can make or break a company's financial targets for success. To improve the operational efficiency of o-rings, gaskets diaphragms, valves and pump stators, perfluoroelastomer seals may be the right choice.

Related Companies

FFKM o-rings are able to maintain their elastic properties, such as compression set resistance.
FFKM o-rings are able to maintain their elastic properties, such as compression set resistance.
(Bild: Dyneon)

Seal failure and maintenance are perhaps the most frequent sources of both planned and unplanned downtime in chemical and pharmaceutical production plants. Hardly a surprise, as the combined effects of high operating temperatures with the presence of aggressive chemicals, such as amines, acids, bases and solvents, take their toll on sealing components. Pressure variations, water and steam, compression and decompression, vacuum and motion also contribute to the deterioration and demise of the performance of a seals and hence can compromise the service life of the product.

In pharmaceutical applications, the conditions and the regulatory standards can be even more exacting, particularly, because of cleaning, sanitary and sterile processes, as well as toxicity and biocompatibility issues. Applicable standards here include United States Pharmacopoeia Plastics Designations (USP) and ISO 10993. Factors in this industry include the need for manufacturing to take place in precise, planned processes with critical time parameters and the need for products to remain completely free from contamination, particularly from seal lubrication media.

Perfluoroelastomer Advantages

In the search to find ways of reducing downtime, and environmental and occupational safety hazards, chemical and pharmaceutical manufacturers have discovered the benefits of high-performance perfluoroelastomer materials and are increasingly turning to these exceptionally durable elastomers as the preferred materials for their sealing applications.

Perfluoroelastomers (FFKM's), are elastomers with fully fluorinated backbones. Their C-F bonds are the strongest in organic chemistry and are highly resistant to attacks. Crosslinking technologies are used in the manufacturing process for these materials, which makes it possible to enhance and customize their thermal and chemical resistance properties to high levels. FFKM's can be highly resistant to heat (over 300 °C) and aggressive chemicals. When exposed to these environments, an FFKM is able to maintain its elastic properties, such as compression set resistance and low volume swell, making it longer-lasting in sealing applications than other conventional elastomeric types.

Compression set resistance, the equivalent of elastic memory, is an indication of a material's ability to retain its elasticity, form and dimensions after a force that had been applied to it has been removed. Temperature plays a decisive role here. With the increase in temperature, the aging process of the elastomers speeds up and eventually leads to the polymer backbone and crosslinks breaking down, causing compression set performance to diminish. For seals, this means subsequent leakage and results in process downtime. The compression set retention of an FFKM far outperforms that of other elastomeric types.