[QuadList] Plasticizer

[Steve Greene]

Walter,
I worked with a sizable collection of two-inch that straddled the
non-backcoated (3M's 849 and 399) and backcoated (400) tape stocks.  The
white crystalline deposits were common on the backcoated stocks and
non-existent on the non-backcoated stuff.  I suspect it was part of a
program to create stocks that were more supple and less prone to flaking
off the base.
 
Unless you've heard from a materials chemist, I'm leary of unilaterally
declaring it "plasticizer".  I tend to think of it more generically as a
binder hydrolysis by-product.  This fits with the similar experience on
the audio side of the appearance of new back-coated tape stocks being
linked to sticky-shed.
 
Steve Greene
Audiovisual Archivist
Nixon Presidential Library and Museum
(301) 837-1772

>>> walterforsberg at gmail.com 3/17/2010 11:15:02 AM >>>

Hello Quad Groupers-
 
I'm looking for info / documentation / personal experiences any of you
may have had with white plasticizer, offering itself up from the
winds/packs of 2" and 1" videotape. 
 
Specifically, are there any trends or commonly believed reasons for
this stuff appearing? (Eg. specific stocks, a particular environmental
storage condition, or manufacturer's container / reel materials.)
 
I'd also be happy to receive a quoted forward of past discussions on
this topic, as I'm a relative newbie to the list. 
 
Happiest shamrocks & thanks in advance,
 
Walter Forsberg
NYU-MIAP
 

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