Mylar Polyester Flms

DuPont Teijin Films Re-Introduce High Performance Kaladex® PEN Films for Demanding Applications



WILTON, UK – 2nd August 2021 – DuPont Teijin Films is pleased to announce the re-introduction of Kaladex® polyethylene naphthalate (PEN) high performance polyester films, first manufactured at our facility in Dumfries in the United Kingdom in 1992 and now once more commercially available.

As the original inventor of polyester film, DuPont Teijin Films has close to 70 years of experience in the design, development and manufacture of products for a wide range of industries. Polyethylene terephthalate (PET) films under the Mylar® and Melinex® brands are highly respected market leaders in many demanding applications around the globe, offering reliability, consistency and best-in-class properties. The distinct polymer chemistry of Kaladex® PEN films builds on this heritage by adding several superior properties to the well-known performance of PET films such as Mylar®. The resulting property set provides cost-effective solutions with an enhanced performance level positioned between that of PET films such as Mylar® and Melinex®, and higher cost engineered films such as polyimides.

Kaladex® PEN films offer a higher glass transition temperature than PET and demonstrate superior long term ageing performance at elevated temperatures. Other inherent properties include better dimensional stability and significantly greater stiffness than PET. However, Kaladex® PEN films are manufactured using the same stenter processes thereby offering the familiarity of similar handling and conversion. They are biaxially oriented and heat-set to give an optimum balance of crystalline and amorphous regions, providing mechanical and thermal resilience combined with toughness and flexibility. The resulting balance between performance and cost makes Kaladex® PEN films well suited to a wide range of applications including electrical insulation, flexible printed circuits, capacitors, and a range of high-performance industrial applications including belts, casting substrates, speciality packaging and several emerging technologies such as electric vehicles, batteries and fuel cells.

The leading expertise of DuPont Teijin Films in polymer science and film manufacturing technology combined with 30 years of unbroken experience with PEN films provide the basis for a highly attractive product range. The re-introduced range of Kaladex® PEN films from Dumfries is available from a thickness of 16-125um and is particularly suitable for a wide range of industrial, electrical and electronics applications. In order to provide a coherent product offering the longstanding established range of thin and ultra-thin PEN films for the capacitor industry, available at thicknesses between 1.2 and 12.0 microns from our plant in Luxembourg, will also be branded as Kaladex® going forward.

This expanded range of Kaladex® PEN films from DuPont Teijin Films will address new market opportunities in applications with technical requirements beyond the limits of PET performance where it is uneconomical to use higher cost materials. Kaladex® PEN films can also facilitate lower manufacturing costs with reduced wastage, increased production yields and better throughput in critical applications. An added benefit is security of supply from a trusted partner.

Kaladex® PEN films are qualified in several applications with further opportunities under development.  Samples of the current Kaladex® grade range are available for testing, evaluation and commercial sale, with further grades to follow as the market demands.

DuPont Teijin Films, a joint venture between DuPont and Teijin Limited, is the world’s premier producer of polyester films and related services for Healthcare, Alternative Energy, Durable Media, Electronics, Specialist Packaging, Electrical Insulation and Capacitors industries and many more. Only DuPont Teijin Films manufactures MYLAR®, MELINEX® and KALADEX® brand films. Please visit our website at or contact us on

2nd August 2021

All products, unless otherwise noted, denoted with ™, ℠ or ® are trademarks or registered trademarks of DuPont Teijin Films.


Media Contact:

Caroline Wray

+44 (0)1642 572084