PTFE film is a film made of polytetrafluoroethylene, in everyday use mostly called Teflon after the Chemours brand name. It withstands continuous temperatures up to 260 degrees, resists almost all chemicals and has one of the lowest friction coefficients of any plastic. As an insulation material it is chosen where standard films such as polyester reach the limit of their temperature or media resistance: in heaters, in aggressive chemical environments and as a sliding and release layer.
PTFE film from GOBA: supply forms, thicknesses and enquiry
GOBA supplies PTFE film from a single piece, as material or as a finished part to your drawing.
- Supply forms
- Roll and slit roll, Cut-to-size, Die-cut part to drawing
- Thicknesses
- To your specification. GOBA processes materials from 7 µm to 3 mm.
- Versions
- Skived and cast PTFE film, depending on thickness and application.
- Slit rolls
- Widths from 5 to 1,600 mm, tolerance ±0.1 mm, cores of 25, 55, 76 or 152 mm
- Die-cut and formed parts
- Material thickness 0.023 to 3.0 mm, dimensions up to 1,000 × 2,000 mm
- Quantity
- From 1 piece, from sample to series
- Lead time
- Two weeks at most when the material is in stock
What we need for your quotation
- Drawing or dimensions
- Quantity
- Material and thickness
For rolls also width, length, core diameter, core material (for example plastic) and tolerances.
What PTFE film is
PTFE is a fully fluorinated polymer, every carbon atom carries two fluorine atoms. This dense fluorine shell makes the material chemically inert and heat-resistant, but it also stops the material from being melt-processed like other thermoplastics. The usual extrusion from the melt is ruled out. PTFE film is therefore made by two detours: by skiving from a pressed and sintered block or by casting from dispersion. It belongs to the electrical insulation films, but differs fundamentally from polyester film in its production.
This fluorine shell has an awkward downside: nothing sticks to PTFE, not even adhesive. If the film is to be laminated or bonded, one side is chemically etched, usually with a sodium-naphthalene solution. Only the etched, roughened surface can be printed, laminated or glued to a carrier. For pure release and sliding layers the film stays untreated, precisely because nothing should adhere to it.
Properties
The combination of temperature, chemistry and low friction makes PTFE special. No other common film material covers these three points at once.
- Continuous temperature minus 200 to plus 260 degrees, higher for short periods.
- Resistant to acids, alkalis and solvents, attacked only by molten alkali metals and fluorine.
- Friction coefficient around 0.05 to 0.10, the material slides and does not stick.
- Dielectric strength roughly 20 to 60 kV per millimetre, depending on thickness and production.
- Dielectric constant about 2.1, one of the lowest among plastics and very stable over frequency and temperature.
- Water absorption practically zero, plus weather and UV resistance.
Mechanically PTFE is softer and less tensile than polyester or polyimide. It tends to creep under sustained load. Where the film carries a load, plan for this.
Pure PTFE film is electrically white, meaning translucent to milky. For some applications PTFE is mixed with fillers such as glass fibre, bronze or carbon, which raises compressive strength and lowers creep, but costs part of the chemical resistance and the dielectric quality. For electrical insulation the unfilled film is therefore used, while filled grades belong in the mechanically loaded sliding application.
Production
Two routes are common, and they yield different films. Skived film is peeled from a rotating, sintered billet as if from a roll. It is available thicker, has a slightly rougher surface and reaches into the millimetre range. Cast film is made from aqueous PTFE dispersion applied in layers, dried and sintered. It is thinner, more uniform and smoother, typically from about 25 micrometres. For thin dielectric layers cast film is the rule, for thicker sliding and release layers the skived film.
How PTFE differs from PET and polyimide
PTFE is not always the right film. The polyester film (PET) is mechanically stronger, much cheaper and, at around 130 to 155 degrees, sufficient for most standard applications. Where only temperature counts and chemistry is uncritical, polyimide, known as Kapton, often beats PTFE: it also holds up to around 240 to 400 degrees, but is far more tensile and dimensionally stable and available in thin plies from 12 micrometres. PTFE plays its strength when chemical attack, low friction or non-stick behaviour are added. As a rule of thumb: PET for the standard, polyimide for thin and dimensionally stable under heat, PTFE for chemistry and sliding.
Applications
PTFE film sits where heat and aggressive media meet. In chemical and semiconductor production it serves as a chemically resistant insulating and lining layer. In plant engineering it is used as a release and sliding layer, as a seal and as a non-stick coating, for example on heated rollers and sealing bars. In electrical engineering it insulates high-temperature and high-frequency assemblies, because the low dielectric constant keeps signal losses small. Add cable wrapping, capacitors and release films in composite production.
A typical case from our production is the release layer on heated tools. Where plastic is welded, pressed or formed, the PTFE film keeps the workpiece from sticking to the hot bar or plate, and it holds the temperature over thousands of cycles. In electrical engineering it serves as a thin insulating layer between conductors that run hot in continuous operation, where the low dielectric constant and the thermal reserve are decisive, not the price.
Cutting at GOBA
PTFE film comes as roll stock and can be slit, stamped and converted. The low friction and the softness make their own demands during cutting: the material slips, it stretches under tension and it frays with a blunt tool. We slit narrow strips to tight width tolerance and stamp formed parts, seals and release layers to drawing.
- Roll slitting in narrow widths with a straight, clean edge.
- Stamped parts such as discs, seals and release layers to your drawing.
- Conversion of skived and cast film, depending on thickness and application.
GOBA Takeaway
PTFE film is the choice when heat and chemistry or sliding properties come together. Where only temperature counts, polyimide is often more dimensionally stable, where the standard suffices, polyester is cheaper. We help with the choice and the right build-up. GOBA has been slitting and stamping PTFE and many other films since 1959. Ask for the matching insulation materials, or send your drawing for cutting from polyester films and other materials. You will receive a technical quote.
