Teonex® - PEN film

PEN film between Mylar® and Kapton®.

If you are looking for a film that has a higher classification than class B (130°C) temperature resistance, very good dielectric strength and exceptionally good mechanical properties, you will quickly find that Kapton® could be suitable. But the high price of this Kapton® film correlates with its exceptionally good properties, which, however, are often not needed.

Teonex® from Toyobo Film Solutions Limited™ (formerly from Teijin) meets many of the requirements in the insulation sector at a much more moderate price/performance ratio. The polyethylene naphthalate (PEN) film can be used mechanically up to 160°C (180°C electrically) and has a higher mechanical stability than "normal" PET film.

With Teonex as the basic insulation, it is possible to build up UL Class F insulation systems very well (155°C continuous service temperature). Adhesive tapes such as CMC 61100 or CMC 61200 therefore offer the possibility of meeting the increased requirements without having to immediately use a significantly overqualified and thus expensive Kapton® film.

Due to its lower vapor and gas permeability and chemical resistance, the film also finds applications in other industries.

CMC Klebetechnik supplies film adhesive tapes, laminates, die-cut parts and rolls made from Teonex® PEN film.

Advantages at a glance :

  • Teonex® has 4 times higher hydrolysis resistance (degradation by moisture)

  • Teonex® has a glass transition temperature of 155°C (class F use possible)

  • Teonex® has a reduced shrinkage of only 0.4...1.0% (150°C/30 min; depending on thickness)

  • Teonex® has excellent dielectric strength up to 300kV/mm (25µm)

  • Teonex® has excellent mechanical stability even at elevated temperatures

  • Teonex® is available in thicknesses of 25µm and 50µm (other thicknesses on request)

Teonex PEN-Folie und Klebeband
      CMC Type
      Breakdown voltage (Veff.)
      Features

      CMC 29725
      PEN film Teonex® Q5300
      non-adhesive

      Film thickness: 0.025 mm
      -
      -
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      CMC 29750
      PEN film Teonex® Q5100
      non-adhesive

      Film thickness: 0.050 mm
      -
      -
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      CMC 61100
      PEN adhesive tape
      Adhesive: acrylate

      Film thickness: 0.025 mm
      Total thickness: 0.070 mm
      5.000
      Adhesive tape based on a PEN film equipped with a very good adhesive, thermosetting acrylic adhesive, which adheres very well even to many low-energy substrates. Due to the materials used, the material is suitable for Warmth class F. PEN has lower shrinkage, higher hydrolytic stability and lower gas and water vapor permeability than common polyester films


       
      CMC 61144
      PEN adhesive tape
      Adhesive: acrylate

      Film thickness: 0.025 mm
      Total thickness: 0.040 mm
      -
      -
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      CMC 61145
      PEN adhesive tape
      Adhesive: acrylate

      Film thickness: 0.025 mm
      Total thickness: 0.040 mm
      ≥ 5.000
      CMC 61145 is an insulation adhesive tape with excellent electrical properties and highest temperature resistance in the group of polyester films. The acrylic adhesive is high molecular, durable and resistant to hydrolysis. CMC 61145 is supplied with protective cover.

       
       
      CMC 61200
      Laminate of PEN and glass fabric Adhesive: acrylate

      Film thickness: 0.140 mm
      Total thickness: 0.250 mm
      4.500
      Mechanically very robust adhesive tape for bundling and as phase insulation in electric motors (Warmth class F), enormous power reserve due to glass fabric, very good adhesive strength.


      CMC 61325
      Laminate: PEN film with heat-seal adhesive
      Adhesive: Polyester resin based heat seal adhesive

      Film thickness: 0.025 mm
      Total thickness: 0.040 mm
      - CMC 61325 is a laminating film based on a 25 μm PEN carrier film, which is equipped on one side with a polyester resin-based heat-sealing adhesive. The product is supplied with a protective PE cover.



      Adhesive tapes based on PEN films

      For more than 40 years, polyester film has been an established, high-performance insulating material in electrical engineering. The available material thicknesses range from about 4 µm to areas of almost 1 mm. Excellent chemical, thermal and electrical characteristics are convincing in countless applications. Most of the standard insulating tapes from CMC Klebetechnik are based on polyester films with corresponding adhesive coatings.

      However, if a film with a higher thermal load capacity is required, the use of high-performance materials such as polyimide (PI) films has often been the only option. Although the performance data of such PI films is impressive, the price of the films is also significantly higher due to the more complex manufacturing process. Not every application can tolerate this increased price - especially if larger quantities of the insulation film are required.

      Adhesive tapes based on PEN film close the gap between these two well-known materials. According to its chemical structure, polyethylene naphthalate is very closely related to polyethylene terephthalate (PET, polyester). PEN differs from PET mainly in a higher glass transition temperature (Tg), greater mechanical strength and good hydrolysis resistance. In terms of feel and transparency, however, PEN differs less from PET. There are also hardly any differences in terms of adhesive tapes made from the two materials.

      However, the higher glass transition temperature allows the PEN film to be used in applications requiring class F (155 °C) materials. Along with better hydrolysis, chemical and UV resistance, PEN film has become a material valued by electric motor manufacturers and others. Higher efficiency, smaller size, and operation at rated load create a thermal load that materials like Nomex or PEN can withstand better than classic PET films. Lifetime and reliability under overload conditions are significantly improved.

      The real advantage of PEN , however, is in transformer construction. As interlayer insulation, one can use Warmth class B use the well-known polyester film. When building a transformer of the Warmth class F Until a few years ago, it was necessary to use polyimide films, especially for non-impregnated coils, which made the design considerably more expensive.

      The PEN film fills this gap, offering a more cost-effective way to build Class F coils and transformers. The film is classified with a flammability rating of UL 94 VTM-2 and achieves a Relative Thermal Index (RTI) = 180 °C (mechanical), 160 °C (electrical).

      CMC Klebetechnik usually uses the adhesive already used on the PET film for adhesive tapes based on PEN, provided it can withstand the increased continuous service temperature. In this way, familiar components can be used, which then lead to no unexpected results in the tests, for example in the Sealed Tube Test according to UL 1446. Adoption of PEN-based adhesive tapes into existing electrical insulation systems (EIS) is possible in this way at low cost and low risk.

      PEN films are currently attracting increased interest from manufacturers of components for the automotive industry, especially in the context of e-mobility. The higher media resistance plays a particularly important role here - however, the significantly higher price compared to polyester film is also dampening the enthusiasm for use among development engineers.

      PEN film adhesive tapes are available from CMC in the following standard designs:

      CMC 61100 - 25µm PEN film with solvent acrylic adhesive

      CMC 61200 - 25µm PEN film laminated with glass fabric and a solvent acrylic adhesive

      Special designs that are occasionally manufactured:

      Adhesive tapes with 50µm PEN film, PEN adhesive tapes with temperature stable polysiloxane adhesive, PEN film laminated with Nomex and acrylic adhesive.



      Teonex® films offer balanced price/performance ratio

      Robust, temperature-stable polyester films (PET) are processed in large quantities, for example as protective, transparent packaging material or as high-quality electrical insulation. The higher-grade PEN (polyethylene naphthalate) again noticeably expands the possibilities of the bulk material.

      Among technical films above PVC, polyester film is the most common. About 60 million tons of PET film leave the factories of manufacturers every year, first and foremost DuPont, Mitsubishi, Toray, Uflex, Garware and many others. Polyester films impress with their high mechanical strength, excellent dielectric behavior and temperature resistance of up to 200°C in the short term.

      But in many applications, the achievable values are not sufficient. For example, the temperature resistance or the shrinkage of the film under heat. In the search for an alternative material, one finds quite a few rather exotic materials that have their main application in very narrowly defined markets. Polymers such as PEEK (Aptiv™), PEI (Ultem®) or PAI (Torlon®) are just a few examples. The fairly widespread polyimide (Kapton®) would also be a candidate when it comes to extended application temperatures (-269°C - 350°C), for example. But what all high-performance materials have in common is that they are considerably more expensive than the inexpensive mass-produced polyester film.

      PEN was developed at the end of the 1980s. Like PC, PAR, PBT and UP, this material belongs to the group of polyester resins. PEN differs from PET in that it has a higher continuous service temperature (155°C instead of 130°C), significantly higher gas tightness and even better chemical resistance. Degradation by hot water (hydrolysis) is also significantly slower.

      PEN films are manufactured by Toyobo Film Solutions Limited™ (formerly by Teijin) and sold under the name Teonex®. These films represent a link between PET and high performance films. Especially also in price.

      In electrical engineering, Teonex® PEN film is mainly used as capacitor film. With thicknesses in the single-digit micrometer range, the films achieve a significantly higher permissible continuous operating temperature than the usual PP film capacitors. However, PEN now also has a firm place in general electrical engineering.

      The ever-increasing energy density of modern devices, electric motors and transformers requires higher temperature resistance of insulating materials. Instead of polyester with a maximum continuous service temperature of 130°C, PEN can now be used. Teonex® film is specified for a continuous service temperature of 155°C (class F material). In terms of temperature, it therefore also forms a link between the inexpensive PET film and the more expensive polyimide films (Kapton®).

      Comparison of important properties between PEN to PET


      PEN
      PET
      Continuous operating temperature
      160°C 130°C
      Heat shrinkage
      @ 150°C/30 min
      0,4 % 1,5 %
      Water vapor permeability (125µm)
      4.1 g/m² d
      1.2 g/m² d
      Hydrolysis resistance (autoclave)
      50 hrs. 200 hrs.
      Glass transition temperature
      155°C 105°C
      Washout of soluble components in chloroform, 25°C
      2 mg/m² h
      15 mg/m² h
      UV transmittance
      Low / blocking (<380 nm)
      High
      Oxygen permeability (cm³/m² d)
      0,001 0,01