Mylar

Written by: GOBA Editorial Team·March 1, 2026·3 min read

Mylar is the brand name for biaxially oriented polyester film (BOPET) from Mylar Specialty Films, the successor company to DuPont Teijin Films. Chemically it is polyethylene terephthalate, stretched lengthwise and crosswise after film extrusion, which gives the film its tensile strength, dimensional stability and dielectric strength. GOBA processes Mylar as an electrical insulating material: as roll goods, cut-to-size formats and stamped parts for transformers, motors and capacitors.

Mylar film from GOBA: supply forms, thicknesses and enquiry

GOBA supplies Mylar film from a single piece, as material or as a finished part to your drawing.

Supply forms
Roll and slit roll, Cut-to-size, Die-cut part to drawing, Formed part (folded, embossed or bent)
Thicknesses
12 to 350 µm
Versions
Mylar, HOSTAPHAN and other BOPET films. If your drawing specifies a brand, we supply exactly that brand.
Slit rolls
Widths from 5 to 1,600 mm, tolerance ±0.1 mm, cores of 25, 55, 76 or 152 mm
Die-cut and formed parts
Material thickness 0.023 to 3.0 mm, dimensions up to 1,000 × 2,000 mm
Quantity
From 1 piece, from sample to series
Lead time
Two weeks at most when the material is in stock

What we need for your quotation

  • Drawing or dimensions
  • Quantity
  • Material and thickness

For rolls also width, length, core diameter, core material (for example plastic) and tolerances.

Send enquiry
Giuseppe Juliano

Your contact

Giuseppe Juliano, Technical Consulting

+49 7153 9439 16 · juliano@goba.de

Mylar and HOSTAPHAN: two brands, one material, different manufacturers

Mylar and HOSTAPHANare both biaxially oriented PET films and, in practice, technically near interchangeable. The difference lies in the manufacturer, not the base material: Mylar comes from Mylar Specialty Films, HOSTAPHAN from Mitsubishi Polyester Film GmbH. Many competitor pages lump both names together with Melinex (manufacturer: DuPont Teijin Films Luxembourg) and treat them as synonyms. For procurement that distinction matters: type series, available coatings and lead times differ by manufacturer even though the base material is the same. For a drawing that specifically calls out “Mylar” or “HOSTAPHAN”, GOBA supplies that exact brand rather than an interchangeable BOPET equivalent.

What technical properties does Mylar have?

PropertyValue
Continuous operating temperatureup to 130 °C, thermal class B per IEC 60085
Short-term peak temperatureup to about 150 °C
Dielectric strengtharound 180 V/µm
Water absorptionaround 0.3 %
UV resistancenone, unsuitable for outdoor use
Appearance from about 190 µmincreasingly hazy instead of clear

Many sources quote the 130 °C continuous rating and the 150 °C peak value without distinguishing them. For sizing an insulation system, the continuous rating under the thermal class is what counts, not the short-term peak.

Where is Mylar used in electrical engineering?

In insulation applications, Mylar works wherever a thin, dimensionally stable, electrically insulating film is needed: as slot lining and layer insulation in electric motors, as winding film in transformers, and as the dielectric in film capacitors. Outside electrical engineering, the Mylar name also shows up for emergency blankets, balloons, and generically for card-sleeve storage bags among collectors. These uses share the base material but have nothing to do with GOBA's core business as an insulation material converter.

How does GOBA supply Mylar?

GOBA converts Mylar and comparable BOPET films in thicknesses from 12 to 350 µm, as slit rolls from 5 mm width with a width tolerance of ±0.1 mm, or as stamped molded partsto drawing. This runs on GOBA's polyester film production line, where Mylar is carried alongside HOSTAPHAN as one of several manufacturer brands.

A common question: if Mylar and HOSTAPHAN are technically near identical, why not simply take whichever brand is available? For most applications that is indeed possible, and GOBA advises openly toward the more economical option. Once a drawing, a UL listing or a customer specification names a specific brand, GOBA supplies exactly that brand, with no silent substitution.

GOBA Takeaway

Mylar is one of two market-leading BOPET brands that GOBA processes as an electrical insulating material. Most searches for Mylar mean interchangeable BOPET; some specifically mean the Mylar Specialty Films brand. GOBA supplies both and names the difference instead of blurring it.

Do you have a specific requirement?

Contact us to find the optimal solution for your needs.

Related glossary terms

Deepen your knowledge with related articles.

  • Polyester Film

    Polyester film is biaxially oriented PET film (BOPET) made from polyethylene terephthalate, used in electrical insulation as thermal class B with a continuous rating of 130 °C.

  • HOSTAPHAN

    HOSTAPHAN is the brand name of the biaxially oriented PET film made by Mitsubishi Polyester Film in Wiesbaden, which as RN and WN insulates electrically in thermal class B up to 130 °C and withstands a breakdown voltage of 12 kV at 50 µm.

  • Electrical Insulating Films

    Electrical insulating films are thin plastic films that separate live parts, from polyester film in class B (130 °C) to polyimide film in class R (220 °C), with breakdown values per thickness defined in IEC 60674.

  • Electrical Transformer

    A transformer changes the voltage of alternating current through electromagnetic induction. Structure, operating principle, types and the insulation system explained.

  • Thermal Classes of Insulation

    Thermal classes of insulation classify insulating materials according to their maximum operating temperature in line with DIN EN 60085.

FAQ: Frequently Asked Questions about Mylar

What is the difference between Mylar and HOSTAPHAN?

Both are BOPET films and technically near equivalent. The difference is the manufacturer: Mylar comes from Mylar Specialty Films, HOSTAPHAN from Mitsubishi Polyester Film GmbH. Type series, coating options and availability differ by brand.

Is Mylar the same as polyester film or PET film?

Mylar is a brand, polyester film (PET film) is the generic term. Every Mylar film is a polyester film, but not every polyester film is Mylar.

Is Mylar heat resistant?

Mylar can be used continuously up to 130 °C (thermal class B per IEC 60085) and withstands short-term peaks up to about 150 °C. It is not fireproof and melts at significantly higher temperatures.

Is Mylar UV resistant?

No. Mylar is not UV-stabilised and is unsuitable for permanent outdoor use.

What thicknesses does GOBA supply for Mylar?

GOBA converts Mylar in thicknesses from 12 to 350 µm, as slit rolls from 5 mm width or as stamped molded parts to drawing.