O-ring lexicon

Compound

A compound is the finished elastomer mixture used to manufacture an O-ring. It consists of the base polymer and all additives, formulated to meet the required properties.

What is a compound?

“Compound” is the technical term for the complete material formulation of an O-ring. It consists of the base polymer—such as FKM or FFKM—as well as crosslinking agents, fillers, and other additives. It is only the combination of these components in specific proportions that determines the properties of the final seal. Two compounds based on the same base polymer can differ significantly in hardness, temperature resistance, and approvals. The term “compound” thus refers to the mixture as a whole, not to a single component.

Why the Compound Is Important for O-Rings

The compound determines what the O-ring is capable of in a given application. Temperature ranges, chemical resistance, hardness, and approvals are all defined by the compound. When selecting a seal, the designer is therefore not just choosing a polymer, but a specific compound. Our proprietary ECOLAST brand, made from FFKM, offers several optimized compounds designed to meet a variety of requirements.

Values in the NH Line

Examples of different FFKM compounds (ECOLAST):

NH4700: −20/+270 °C, 70 ±5 Shore A, compliant with FDA, USP VI, and 3-A
NH5751HT: −15/+330 °C, 75 ±5 Shore A, high temperature
NH5760LT: −40/+270 °C, 75 ±5 Shore A, low temperature
NH5901HT: −15/+320 °C, 90 ±5 Shore A, for oil and gas

Key Points at a Glance

A compound is the complete mixture of the base polymer and additives.
Temperature, chemical resistance, hardness, and certifications are specified in the compound.
Based on a single polymer, there are many compounds with different properties.

You can find the individual blends and their specifications in the data sheets and in the product lineup.

You can find the right material for your application in our product range.

Go to the data sheets →