PTFE Gaskets and Sheeting Materials
We are able to offer an extensive range of gasket materials within the PTFE sealing family of products which provide outstanding chemical resistance for duties where hygiene and non-contamination are essential such as food and beverage, petrochemical, chemical, pharmaceutical, vessel lining and electronics industries.
Developed for processes ranging from Cryogenic to +260⁰C and capable of sealing virtually every chemical across the pH range our collective range of products provide superior:
Mechanical properties – One of the most significant characteristics is having the ability in a wide range of service temperatures to possess a compressive strength at a certain predetermined compression value
Electrical Properties – Have excellent dielectric strength, decreasing when the frequency increases
Thermal Properties – Physical and molecular properties do not change in service temperatures up to 260⁰C
Chemical Inertness – Excluding some molten alkali metals and fluorine gas or hydrogen fluoride PTFE is virtually inert to all chemical products
- Multi-Directionally Structured, Bi-axially orientated PTFE
- Expanded PTFE
- Virgin and Filled PTFE
- PTFE Thread Seal Tape
- PTFE Envelope Gaskets
- Extruded PTFE Tube, Rod and Bar
- PTFE Sealing Rings
- PTFE Back-Up Rings
- PEEK, PFA and PCTF
Multi-Directionally Structured, Bi-axially orientated PTFE
Specially developed Bi-axially orientate, multi-directionally structured PTFE in various grades and colours primarily Blue, Pink, Fawn and Off-white and each is specifically developed PTFE containing different filler materials to combat varying service conditions. These filler materials include;
- Hollow Glass Microspheres
- Silica
- Aluminosilicate
- Barium Sulphate
From world leading brands of Gylon®, Sigma®, Top-Chem®, Sichem® and Fluolion® the following benefits, dependant on selected material brand and grade, are;
- All materials FDA approved
- Outstanding chemical resistance sealing media across virtually all the pH Range
- Enhanced compressibility for low bolt loads
- WRAS approved for hot and cold potable water
- Ideal for sealing food, pharmaceutical and other non-contamination applications
- Approved for use in Oxygen service
- Stainless steel reinforcements for improved pressure resistance
- Use on glass lined equipment
- Low creep resistance
- Low coefficient of friction
- Non-Stick
- Non-Flammable
- Moisture and U.V resistance
- Excellent dielectric properties
Expanded PTFE
Available as sheet and cut in to any gasket size or shape or in tape/cord form with adhesive backing for ease of installation.
ePTFE is manufactured from 100% Virgin PTFE which is expanded and stretched during the manufacturing process. It is a food approved product, has enhanced low stress sealing characteristics, a reduced tendency to creep under load at elevated temperatures and shows good mechanical recovery. It can operate throughout the pH Range, is resistant to thermal cycling and is non-contaminating therefore allowing it to be used in virtually any industry. Due to the very soft nature of the product it has a low bolt load requirement so is very useful in applications with worn and damaged flanges with uneven sealing faces
- 100% Pure Expanded Virgin PTFE, no fillers or pigments
- FDA compliant
- Enhanced low stress sealing
- Improved blow-out resistance
- Cryogenic to +260⁰C
- Chemically inert across virtually the whole pH Range
- UV Resistant
- Soft and conformable to uneven sealing faces
Available from stock in standard sheet form 1.5 metre Square in thicknesses from 0.5 mm to 10mm and also in adhesive backed tape form from 3 mm to 25 mm width and thicknesses from 1.0 mm to 7.0 mm
Virgin PTFE and Filled PTFE
Virgin PTFE – More commonly referred to by the Dupont trade name Teflon® this Virgin PTFE material is available in sheet form to cut as gaskets or can be molded as Tube, Rod and Bar and machined to form components of many different sizes and shapes for use in applications using food, potable water and pharmaceutical products
Beneficial Properties include
- High Chemical resistance
- Temperature range Cryogenic to +260⁰C
- Low coefficient of friction
- FDA approved
However, Virgin PTFE does have poor mechanical strength and tends to fail in PV applications, the strain is very high too. To overcome this there are several different types of filler that can be added to improve the mechanical properties over varying applications and service conditions. In order to decide which of the following fillers will give best results for a specific application you must first of all determine exactly what properties need to be achieved. i.e is it fundamental to have compressive strength. Is thermal conductivity important. Is increased or decreased friction required. Does product need to be hard wearing. Is electrical conductivity paramount and so on.
Glass Filled PTFE – Adding glass (between 5% to 40%) to PTFE provides much improved compression and wear properties, and makes it stronger and more durable, as well as reducing flexibility and creep. The higher the percentage of glass filler results in an increase in durability and compressive strength. This also however, makes the product more abrasive and also increases the coefficient of friction
Carbon Filled PTFE – Adding Carbon as a filler to PTFE, from as little as 0.2% up to 40%, can result in excellent mechanical and wear properties whilst maintaining excellent friction properties making it an ideal choice for sealing rings in dynamic and high pressure applications. Using this Carbon filler also adds good thermal conductivity and low permeability. It also electrically conductive making it a good choice for anti-static applications.
It must be recognised that different percentages of Carbon used will display different material properties and performance as will the actual carbon powder/fibre used. Not all carbon fillers are the same, in fact, they can be very different.
Graphite Filled PTFE – Adding a graphite filler to PTFE gives excellent self lubricating properties lowering the coefficient of friction. It can be combined with carbon and/or glass fillers also, to give further benefits associated with each of these other fillers.
Bronze Filled PTFE – Using Bronze powder as an additive from between 40% and 60% improves wear resistance. It does unfortunately reduce chemical inertness but on the other hand it does greatly increase hardness and compressive strength, and also gives better dimensional stability and reduces creep and cold flow. It also increases thermal and electrical conductivity.
Molybdenum Disulfide (MoS²) Filled PTFE – Adding Mos² to PTFE results in a more slippery and harder material improving compression and wear resistance making the product very useful for dynamic sealing applications. It has low static coefficient of friction and a reasonably good resistance to deformation. It can also be combined with glass or bronze
Stainless Steel Filled PTFE – Adding stainless steel powder to PTFE tremendously increases strength and the ability to withstand loads at exceptionally high temperatures whilst retaining a low coefficient of friction. Used in applications with steam and thermal fluid it is also a very good seat material in Ball Valves due to its high wear resistance.
Synthetic Filled PTFE – A synthetic polymer can be added to PTFE that can be lower in friction to all of the above fillers. It is non-abrasive so is useful on applications where there are soft material mating faces and also suits dry running applications particularly well. This is however, unfortunately a very expensive filled PTFE to produce.
PTFE Thread Seal Tape
Thread seal Tape, also known as PTFE tape, Teflon tape or Plumbers tape, is a polytetrafluoroethylene film tape commonly used in plumbing for sealing pipe threads
Thread seal tape lubricates allowing for a deeper seating of the threads helping to seal the joint at temperatures from Cryogenic to +260⁰C
Available from stock as
- Standard Tape: 12 metre spool x 12mm Width x 0.076mm thick
- Single Wrap (Gas Spec): 5 metre spool x 12mm Width x 0.2mm thick
- Tape for use with Oxygen: 12 metre spool x 12mm Width x 0.1mm thick
- Other tape widths are available on request
PTFE Envelope Gaskets
This product consists of a central gasket core partly encased in PTFE which ultimately combines the inertness of virgin PTFE with the mechanical properties, strength and resilience of the insert gasket. This type of gasket would be used in applications handling aggressive chemical fluid media that would normally destroy general gasket materials. Also used with a soft gasket material on glass-lined pipework systems and in food processing where cleanliness and non-contamination are essential.
We have three standard styles of envelope design each one capable of varying the material choice of the insert gasket in order to best suit the application service conditions. Gaskets are available as standard DIN,ANSI, JIS size flanges and can also be manufactured to suit any bespoke size or shape.
Fin Type – This is the most common standard and most cost effective style of envelope gasket production. This style suits the majority of applications where highly abrasive media is not present and turbulent flow will not create problems.
Machined Square Section Type – This design of manufacture provides continuity with pipeline bore for smooth flow and is recommended where flange sealing width is restricted or where the insert thickness is greater than 3mm.
Folded Tape Type – This uses PTFE tape that is folded and joined by welding. Most generally recommended for diameters over 300 mm or for non-circular design shapes
