Insulating foilsJohn Moot
When developing electrical devices such as electric motors, generators, controls and other equipment, developers are often faced with the question of which insulation films should be used.
The well-known insulation foils are often used:
- Polyester film
Polyester films such as PET and PEN insulation films
For simple electrical insulation applications where a thin film is required, polyester films are probably the most common type of flexible electrical insulation material.
Polyester films are commonly referred to as either PET (polyethylene terephthalate) or PEN (polyethylene naphthalate).
The actual differences lie in the chemical composition and the resulting physical and electrical insulation properties of the two insulation foils.
PET films, such as B. Mylar, Hostaphan or Melinex, offer good dielectric resistance within a relative temperature range (Tg of +78 ° C), while PEN films (Teonex) typically offer similar electrical performance in a much higher temperature range (Tg of +120 ° C ) Offer.
For applications that require higher temperatures, PEN films are often the better choice than PET films, as they are three to four times stiffer at temperatures above + 125 ° C, as well as at the higher operating temperature compared to PET (+180 ° C vs. + 160 ° C).
PEN films are more expensive than PET films, but this cost difference can be worthwhile for critical applications.
In terms of processing, the two insulation foils hardly differ: Both are easy to punch, cut and coat.
These thin sheets of insulation are found in thousands of applications including flexible electronics, battery and motor insulation, and electronic component manufacturing.
In some applications, PEN foils cannot be used due to the temperatures. Then the use of polyetheretherketone (PEEK) or polyetherimide (PEI) materials such as Ultem remains an option.
PEI insulation films
At + 216 ° C, PEI materials have a significantly higher glass transition temperature than PEN insulation films. A common PEI material, the Ultem 1000 film, has a continuous use temperature of + 171 ° C with exceptional flame and heat resistance. Another benefit of the Ultem 1000 material is that it is available in sheet, sheet, tube, or extruded rod form, giving the designer greater flexibility in designing critical mechanical components based on the specific needs of the application.
Just as PEN insulation films are usually more expensive than PET films, the more powerful PEI materials are usually more expensive than PEN or PET films. The specific requirements of the electromechanical component as well as the requirements of the specific application must be considered when selecting the material.
Because of the different forms of material available, PEI materials are widely used in aircraft components, microwave applications, and electrical / electrical components.
If an even higher temperature resistance is required and at the same time the electrical insulation performance is to be maintained, polyimide materials are often used.
Polyimide films have been used as an electrical insulating material for years.
When it comes to high temperatures, electrical insulation is required and deformed parts are to be produced, PEEK film is a good choice. This insulation film is used in aircraft construction, in battery applications and in the manufacture of loudspeakers.