Silicone O-Rings & PTFE Liners

Inside almost every closure is a small component that does the actual sealing, and silicone O-rings and PTFE-faced liners are the premium choices for it. A PTFE (Teflon) facing is about as chemically inert as a sealing surface gets — it resists solvents, acids, oils and high alcohol that would attack ordinary foam or PE liners, and it releases very little into the product.

Silicone O-rings add a compressible, resilient seal that holds across a wide temperature range, from freezer to autoclave, which is why they are used in pharmaceutical, food and laboratory sealing where reliability and inertness matter.

Cap and closure liners, aggressive solvent and acid products, spirits and essential oils, pharmaceutical and sterile fills, swing-top and ground-joint seals, food-contact sealing, and lab and process equipment, including high- and low-temperature service.

Platinum-cured food- or pharma-grade silicone O-rings in a wide range of internal diameters and cross-sections, and PTFE-faced liner discs (PTFE bonded to a foam or board backing) sized to cap diameters. PTFE faces the product for inertness; the backing provides compression. Food-contact and pharmaceutical grades are available.

Select the seal for the product and process: PTFE-faced liners for aggressive solvents, acids, spirits and oils; silicone O-rings where a resilient seal across temperature extremes is needed. Match the size to the closure or joint and the compression to the application. For sterile or food use, the appropriate clean grade and packaging are specified, and seals are checked for the right durometer and dimensions.

Silicone O-rings are compression- or injection-molded from platinum-cured silicone and deflashed; PTFE-faced liners are made by laminating virgin PTFE film to a foam or board backing and die-cutting to size. Dimensional accuracy, material grade and (for sensitive uses) cleanliness are the key quality checks.