Du Pont
Mylar
Mylar is a type of polyester film (specifically BoPET: biaxially-oriented polyethylene terephthalate), originally developed by DuPont, Imperial Chemical Industries and Hoechst in the 1950s. In the keyboard industry, Mylar found a use as a suitable material for membranes in keyboards of that type.
Products confirmed to use Mylar include:
- Datanetics DC-50 discrete switches
- Cherry solid state capacitive (metallised Mylar pads)
- NMB membrane keyboards
The patent for General Instrument S700 Series also suggests metallised Mylar for the foil covering on the foam pads.
Kapton
Kapton is polyimide film, also developed by DuPont, in the late 1960s. It is not known to have been used in any production keyboards, but the membrane layers of prototype Datanetics DC-50 switches were made from Kapton, before Datanetics changed to Mylar.
Documentation
All documents scanned by Bitsavers unless otherwise noted.
- Mylar advertisement, Electronics, Vol. 36 No. 17, April 26 1963