PTFE Products

Plastics

Of all the plastics, PTFE (Polytetrafluoroethylene) have emerged as the most common plastic gasket material PTFE’s outstanding properties include resistance to temperature extremes from -140 F to 450 F (for virgin material). PTFE is highly resistant to chemicals, solvents, caustics and acids except free fluorine and alkali metals. It has a very low surface energy and does not adhere to the flanges. PTFE gaskets can be supplied in a variety of forms; either as virgin or reprocessed material, and also with a variety of filler material. The principal advantage in adding fillers to PTFE is to inhibit cold flow or creep relaxation.

Virgin / Glass-Filled / Reprocessed PTFE Sheet

Biaxially Orientated PTFE Sheet

Lamons offers biaxially orientated PTFE sheet gasket material that is specifically designed for the chemical industry. The sheet size available is normally 60"x 60" in 1/32", 1/16" & 1/8" thickness, but it is also available in 70" x 70", plus other variations of thickness. The material is manufactured to ensure the properties are the same in all directions, therefore reducing creep, which is often found in other types of PTFE gasket materials.

This material is available in various grades:

  • A biaxially orientated silica-filled PTFE sheet for use in sealing most chemicals except molten alkali metals, fluorine gas, and hydrogen fluoride. This material is approved for potable water service, complies with requirements of FDA regulations and can be used at all concentrations of sulfuric acid.
  • A biaxially orientated sheet material containing PTFE and hollow glass microspheres for use in sealing most chemicals except molten alkali metals, fluorine gas and hydrogen fluoride. This material is approved for potable water service, complies with requirements of FDA regulations and has exceptional compression characteristics making it good for use in glass lined flanges or where loading problems exist.
  • A pigment-free biaxially orientated, barium sulfate-filled PTFE sheet for use in sealing food, pharmaceuticals, and other general chemical media. This material complies with requirements of FDA regulations and is acceptable for use in aqueous hydrofluoric acid below 49%, but is not suitable for sealing molten alkali metals or fluorine gas.

Expanded PTFE Sheet

Expanded PTFE effectively fills flange imperfections for a tight, leak-free seal. It is easily compressed under lower loads, beneficial for applications such as FRP or glass-lined flanges. Unlike conventional PTFE, which is prone to creep and cold flow, expanded PTFE has good creep resistance and bolt torque retention properties even under higher compressive force. With expanded PTFE, it is much more possible to bolt up once and not have to retorque later. Most commonly FDA/USDA suitable.

PTFE Joint Sealant

100% pure, specially processed PTFE sealant provides soft, highly compressible gasketing on a roll for long- life, trouble-free sealing that cuts maintenance and storing costs. Under pressure, PTFE sealant provides a very thin and wide ribbon-like joint sealant so that the smallest possible gasket surface area is exposed to the harmful effects of corrosive media.

PTFE Envelope Gaskets

Envelope gaskets utilizing PTFE jacket have become popular for use in severely corrosive services because of their low minimum seating stresses, excellent creep resistance, high deformability and choice of a variety of filler materials to assure optimum performance on any specific application. Fillers such as corrugated metal and rubber sheets are available.

There are three basic designs of envelopes:

  • Slit Type: sliced from cylinders and split from the outside diameter to within approximately 1/16” of the inside diameter. The bearing surface is determined by the filler dimensions. Clearance is required between the I.D. of the filler and the envelope I.D. The gasket O.D. normally rests within the bolt hole circle and the I.D. is approximately equal to the nominal I.D. of pipe. Available in sizes to a maximum O.D. of 24”.
  • Milled Type: machined from cylinder stock. The jacket is machined from the O.D. to within approximately 1/32” of the I.D. The jacket I.D. fits flush with pipe bore and the O.D. nests within the bolts. Available in sizes up to a maximum O.D. of 24”. Milled envelopes are more expensive than slit type since considerably more material is lost in machining.
  • Formed Tape Type: large diameter (over 12” NPS) and irregularly shaped envelops are formed from tape and heat sealed to produce a continuous jacket construction.