Question about DECtape formulation

[Noel Chiappa]

    > From: Gary Oliver

    > I've always thought the physical tape wound on a DECtape spool was a
    > fairly conventional 'sandwich' of mylar/oxide/mylar ...
    > Was there some kind of 'lubricating' coat on the data side? It makes
    > sense, but none of my DEC documents or Googling has any mention of
    > lubrication ...
    > If someone has some detail information on the tape construction, I'd am
    > curious to see it.

Dunno if you know of this:

  http://www.bitsavers.org/pdf/dec/dectape/3M_DECtape_Spec_Nov66.pdf

but it doesn't mention any lubrication, just a "Protective Overlay" layer,
over the "Coating" (which I assume is the oxide). I'm a bit surprised that
"some of the data side of the tape came off on the wipe", though, unless the
"various concentrations of isopropanol/water" dissolved the Protective
Overlay.

	Noel