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 -140ºF to 450ºF (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.

Matrix PTFE

Premium Biaxially Oriented PTFE Sheet Material

Lamons Matrix gasketing material is a premium sealing material specifically designed for use in critical piping systems where superior chemical resistance and performance is required. Produced using the HS10 method developed by DuPont® in 1960, the result is a material that has exceptional strength and stability under load. The resultant biaxial orientation of the PTFE particles creates a unique strength where both the longitudinal and transverse directions are equally as strong. This superior matrix orientation and addition of premium fillers allows the material to resist creep and cold flow when subjected to load.

PTFE (commonly referred to as "Teflon®" which is a trade name owned by DuPont) is a fluorocarbon solid that has a very high molecular weight. The structure consists primarily of carbon and fluorine. PTFE is very non-reactive, partly because of the strength of the carbon-fluorine bonds. For this reason it possesses exceptional chemical resistance. Because it is chemically inert, PTFE cannot be cross-linked like an elastomer which can be cured with a chemical reaction. Due to this, PTFE has little memory or recovery and is susceptible to creep and movement under load. While this feature is desirable from a conformance standpoint, it can be a detriment to maintaining load. Lamons Matrix manufacturing process allows the addition of fillers which are consistently and precisely dispersed throughout the mix. These fillers add body and stability to the finished gasket material resulting in a superior balance of surface conformance and creep resistance. This filler system and the biaxial orientation resultant from the HS10 process result in one of the highest performance PTFE sheet gasket materials available in the market.
Complies with the requirements of FDA21 CFR 177.1550, TA-LUFT
Test information is available for: HOBT, ROTT, EN 13555

Matrix L100   Matrix L104   Matrix L110
Matrix L100   Matrix L104   Matrix L110
A biaxially orientated high quality 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 superior performance, 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 with superior performance, 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.

Typical Physical Properties

Style
Matrix L100
Matrix L104
Matrix L110
Color
Tan
Blue
Off White
Density
13.7 lbs/ft3
(2.2 g/cc)
87 lbs/ft3
(1.4 g/cc)
18 lbs/ft3
(2.9 g/cc)
Temperature Limits
-450ºF (-268ºC) to
500ºF (260ºC)
-450ºF (-268ºC) to
500ºF (260ºC)
-450ºF (-268ºC) to
500ºF (260ºC)
MAX Pressure
1235 psi (8.5 MPa)
1235 psi (8.5 MPa)
1235 psi (8.5 MPa)
F36 Compression
7%
35%
6%
F36 Recovery
45%
45%
40%
F152 Tensile Strength
2320 psi (16 MPa)
1885 psi (13 MPa)
2030 psi (14 MPa)
F37 Liquid Leakage
<0.3 mL/hr
<0.25 mL/hr
<0.2 mL/hr
F38 Creep Relaxation
35%
31%
13%
F149 Dielectric Strength
20 kV/mm
15 kV/mm
21 kV/mm
Residual Stress BS7531 @ 175ºC
4496 psi (31 MPa)
4351 psi (30 MPa)
4351 psi (30 MPa)
DIN Residual
Stress @ 175ºC
4351 psi (30 MPa)
4351 psi (30 MPa)
4061 psi (28 MPa)
Gas Leakage -
DIN 3535
<0.01 mg/(s-m)
<0.02 mg/(s-m)
<0.01 mg/(s-m)
Gas Leakage - BS7531
<0.005 mL/min
<0.01 mL/min
<0.004 mL/min
ROTT Constant Gb
172
23
146
ROTT Constant a
0.401
0.322
0.375
ROTT Constant Gs
2.76 x 10-6
6.42 x 10-3
1.2
Tpmax
2426
16370
60460
m
4
2
2
y
2225 psi (15 MPa)
1700 psi (11 MPa)
1800 psi (12 MPa)

Virgin / Glass-Filled / Reprocessed PTFE Sheet

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.

Typical Physical Properties
Property
ASTM Method
Typical Values
Compressibility
F-36
68%
Recovery
F-36
12%
Sealabilty
F-37-B
0.00 (Fuel A)/0.02 ml/hr (Nitrogen)
Creep Relaxation
F-38
32% @ 212°F / 16% @ 73°F
Temperature Limit
Cryogenic to 450°F
Pressure Limit
Full vacuum to 3000 psi

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.