Featured Product – Kaladex® PEN Films for Harsh Environments

Kaladex® is a brand of hazy, biaxially-oriented polyester PEN films developed by Mylar® Specialty Films (formerly DuPont Teijin Films™) that has several enhanced properties designed to endure harsh environment applications. This specialty polyester film, known as polyethylene naphthalate (PEN), is manufactured using the same stenter oven processes as Mylar® and Melinex® PET films to produce a semi-crystalline structure featuring all of the familiar advantages inherent in biaxially-oriented polyester films: thermal and mechanical stability, chemical resistance, toughness, flexibility, and good dielectric properties.

Some common Kaladex® products are:

Kaladex® PEN Films Offer Enhanced Properties Over PET Films


Additionally, Kaladex PEN films offer performance improvements over standard polyester PET such as:

  • Thermal Resistance – higher glass transition temperature than PET film and superior long term aging performance at elevated temperatures (RTI), exceeding both mechanical and electrical Class F insulation standards for motors
  • UV Resistance – inherent screening of non-visible UV radiation below 380 nanometers
  • Moisture & Oxygen Barrier – lower moisture and oxygen permeability than BOPP and BOPET films
  • Dimensional Stability – low shrinkage and maintains retention of mechanical properties even at elevated temperatures
  • Mechanical Strength – better tensile strength and 25% higher stiffness (Young’s modulus) than PET
  • Hydrolysis & Alkali Resistance – improved resistance to deterioration from extended exposure to water or alkaline chemicals even at elevated temperatures, such as those that make up the liquid electrolyte within a lithium-ion battery cell
  • Reduced Oligomer Bloom – very low levels of extractable oligomers under intense heat, making it ideal for insulation in hermetic compressor motors

Common Applications


Kaladex® PEN film is intended to fill the performance gap between standard polyester PET and high-performance polyimide films, serving as a cost-effective alternative to the latter. It is often used as electrical insulation in applications exposed to high temperatures such as separator films within automotive batteries and fuel cells, solar cells, flexible printed circuitry, flat flexible cables, motors, capacitors, and transformers. It can also be used as a carrier film in manufacturing processes applying intense heat, as a base film in speaker diaphragms due to its exceptional stiffness-to-density ratio, and as a backsheet or protective barrier for rigid and flexible solar cells with its ideal combination of UV resistance, moisture barrier, high light transmission, and thermal stability for high-temperature deposition processes.

Tekra can convert Kaladex® PEN films into custom-sized rolls or sheets to fit your next application. Contact us to learn more.

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