PCTFE / Kel-F / Neoflon

Kel-F type Neoflon M 400H PCTFE, polychlorotrifluorethyene, is the homopolymer of chlorotrifluorethylene. Kel-F, or PCTFE, offers the unique combination of physical and mechanical properties, nonflammability, high optical transparency, chemical resistance, near zero moisture, and excellent electrical properties that cannot be found in other thermoplastic fluoropolymers. It has a useful temperature range of -240 degrees C (-400 degrees F) to +200 degrees.

PCTFE (polychlorotrifluoroethylene), sometimes referred to as Kel-F (a discontinued product from 3M) or Neoflon (a product of Daikin Industries), combines physical and mechanical properties, nonflammability, chemical resistance, near-zero moisture absorption and excellent electrical properties not found in any other thermoplastic fluoropolymer that also performs well in a temperature range of -400° F to 400° F. PCTFE also has high compressive strength, an exceptional resistance to cold flow and is optically transparent. Because PCTFE is a highly fluorinated resin, it is nonflammable and resists most corrosive chemicals. It also maintains its outstanding electrical-insulating capability through thermal cycling and in high-humidity environments.

After World War II, PCTFE was commercialized under the trade name of Kel-F 81 by M W Kellogg company in early 1950s.The name Kel-F were derived from Kellogg and Fluoropolymer, which also represents other fluoropolymers like the copolymer poly(chlorotrifluoroethylene-co-vinylidene fluoride) (Kel-F 800). These were acquired by 3M Company in 1957. PCTFE was developed and manufactured by the 3M Company under the Brand name of Kel-F. In 1995, the 3M Company discontinued the manufacturing of the PCTFE materials and sold the rights to Daikin Industries Ltd. Who now produces the resin under the brand name of Neoflon PCTFE grade M-400H.  The actual 3M Kel-F plastic is no longer available in the marketplace. Kel-F remains the most commonly used trade name still today.

PCTFE Plate, tube and rod is a versatile material whose properties may be modified over a wide range depending upon fabrication conditions. Careful specification of pertinent properties for a given application is advisable.

PCTFE (polychlorotrifluoroethylene) is formed by the polymerization of the homopolymer of chlorotrifluoroethylene. PCTFE is a crystalline polymer whose degree and type of crystallinity can be controlled by its thermal history, especially by how fast it is cooled. This makes PCTFE a versatile material whose properties can be modified over a wide range depending on manufacturing conditions. When molded with high crystallinity, PCTFE is dense and has high mechanical strength and low elongation. However, amorphous molded PCTFE has a lower density, is more elastic and optically clear.

Because PCTFE is not well suited for injection molding certain kinds of parts, compression molding followed by machining is used instead.

PCTFE objects made by compression molding are stronger than those made by injection molding or extrusion.  Because PCTFE isn’t very stable in its molten state, injection molding or extrusion of PCTFE, which require elevated temperatures, can lead to molecular degradation (loss of molecular weight) and reduced properties as revealed by zero-strength-time (ZST) tests (ASTM D1430).  However, expertly performed compression molding doesn’t cause the material to overheat and doesn’t induce a preferential orientation to the material. 

PCTFE / Kel-F / NEOFLON Applications

• Because PCTFE has high dimensional stability and compressive strength, it is a good structural material to use when the high temperature resistance and chemical resistance of fluoropolymers are required.  Although PCTFE has somewhat less heat resistance and chemical resistance than PFA and FEP, its mechanical properties are superior, especially its hardness.
• Low outgassing and permeability make PCTFE ideal for laboratory and aerospace applications.
• PCTFE is used for cryogenic applications such as liquid oxygen and liquid nitrogen handling.  Because PCTFE retains its mechanical properties over a wide temperature range down to almost absolute zero, it is used in refrigeration engineering.
• Because PCTFE absorbs essentially no moisture, direct contact with water or high humidity do not affect its dimensional stability, allowing it to remain an excellent electrical insulator even in adverse climates such as the tropics and marine environments.
• PCTFE has good resistance to ionizing radiation.  It is used in nuclear engineering components and uranium enrichment equipment.
• An expensive, semi crystalline, melt processable thermoplastic. It has a chemical structure similar to that of PTFE but with one chlorine atom substituted for a fluorine atom in the repeat group. PCTFE offers a unique combination of physical and mechanical properties, non-flammability, high optical transparency, chemical resistance, near zero moisture absorption and excellent electrical properties. PCTFE also has extremely low outgassing (0.01% TML, 0.00% CVCM, 0.00% WVR when tested per ASTM E-595-90) and so is suitable for use in aerospace and flight applications.
• Industrial applications include chemical apparatus, process equipment, cryogenic applications, valve seats, seals, gaskets, sight glasses (special process), laboratory equipment, medical equipment, gears, cams and bearings.
• PCTFE also has extremely low outgassing (0.01% TML, 0.00% CVCM, 0.00% WVR when tested per ASTM E-595-90), so it is suitable for use in aerospace and flight applications.
• Cryogenic applications -- super-cold refrigeration components
• Valves -- seats, stems, seals
• Seals -- lips, o-rings, v-rings, special construction seals
• Compressors & pumps
• Films -- food packaging, pharmaceutical packaging, optical recording, electroluminescent display panels
• Gaskets -- pressure, diaphragm, liquid gauge seals, fluid handling
• Bearings -- sleeve & thrust
• Stock shapes -- for machining components

Key Properties

Near-zero moisture absorption

Excellent performance under a wide temperature range

Resists most corrosive chemicals

Excellent electrical-insulating properties

Extremely low outgassing

Standard Shapes and Forms

Sheet: .125” – 1.25” thick

Rod: .125” – 3” diameter

PCTFE / Kel-F / Neoflon Pictures