CD labelling problem

Walter:  It was suggested that I send a copy of this to the dist. since
others also may be having problems labelling CD's.  I don't have answers
for anyone, but I can comment on a number of the problems.

    -----------------------------------
    Date: 2 May 91
    From:         "S. Thomson Moore" <STMOORE [at] PUCC__BITNET
    Subject:      cd mortality !

    History:  Princeton began ordering CDs for its music collection in
    late 1987. My predecessor processed these for the shelf by placing
    two stickers on the label side of each CD - one with the
    call-number, one reading "Woolworth Record Library, Princeton
    University.  Out of ignorance I continued this practice upon my
    arrival in 1989.

    The Problem:  This practice did not lead to any obvious evil
    consequences until April 30, 1991, when we discovered that the
    adhesive seemed to have eaten through the polymer on the label side
    and adversely affected the aluminum. Bye- bye, Bruckner CD (this was
    the only one to show the phenomenon so far). The Solution (?):
    Having removed all the offending labels, we are face with cleaning
    any remaining adhesive from the CD. I have managed to remove any
    visible traces from a sample CD using a solution of warm water and
    dish soap. My question to the list: Is there a better solution to
    this cleaning problem? Will the dish soap adversely affect the
    polymer layer on the label side of the CD? Your responses will be
    very welcome (were we the only library in the US to be so stupid?)
    Tom Moore, STMOORE AT PUCC. cd mortality!

    Date: 2 May 91
    From:         "S. Thomson Moore" <STMOORE [at] PUCC__BITNET
    Subject:      Re: More CD labeling

    Amplification department: Our initial failed CD developed its
    problem at the point where the aluminized section met the
    non-aluminized section (i.e. at the inner edge where the lase begins
    reading the disc). Presumably the polymer coating protecting the
    aluminum layer is thinner here. I should also report that in the
    process of removing the labels we suffered the loss of another
    half-dozen or so CDs and in all cases this juncture was the locus of
    the failure of the protective polymer. None of these failed CDs
    showed the same seep-through upon examination from the playing side,
    but the removal of the label pulled up the polymer and the aluminum
    underneath.  Not a pretty sight.

       It may be worth noting that a recent contributor to PACS-L quoted
    an unnamed source from the National Archives to the effect that
    CD-ROMS may have a shelf- life of only three to five years (I'm
    quoting from memory). Tom Moore, STMOORE at PUCC.

          Re: More CD labeling

    Tom:  I got a copy of your query of May 2 (by usmail) from some
    people at HRC at UT at Austin.  They thought that I might have some
    useful comments.  (Not likely.)  Where can I start?  Optical disks
    of all sorts (not just CD's) are a problem.  They are composed of
    (potentially) many layers of metals or alloys bonded (somehow) to a
    polymer or glass shell (often polycarbonate).  The possible failure
    mechanisms are too numerous to even think about, but they include
    failure of the bonding between the alloys, failure of the polymer,
    and oxidation of the reflective metal. Aluminum happens to be
    notorious for oxidation.  I remember drawing on the bottoms of
    aluminum pots (pre-Alzheimer days) with a match head when I was
    young. The freshly exposed metal layer was much shinier than the
    rest of the aluminum oxide.  Within minutes the writing disappeared
    as the metal was quickly oxidized.  Some optical disk manufacturers
    tried to fix the problem by using platinum, gold or exotic alloys
    instead of aluminum.  This approach tends to be expensive and
    doesn't solve all of the problems.  Polycarbonate tends to be quite
    susceptible to just about any solvents. (Some bikers in Britain died
    because they spray painted their PCarb helmets.)  I also might
    mention the laser rot problems with video disks.  Video disks are
    literally two optical disks glued back to back.  After a few plays
    the picture would disappear into a "cloud" of snow.  Some
    manufacturers claimed that it was water in the glue used to bond the
    two disks together, but many people in the preservation field
    question why it happened with both disks made from American raw
    materials and from Japanese raw materials.  The likelihood of
    contamination getting into so many sources of adhesive seemed pretty
    remote.

    Components of adhesives do migrate through many plastics.  Often in
    photography, the damage is caused by putting adhesive labels on
    plastic sleeves.  Most often the migrating chemicals causes the
    silver in black-and- white photographs to oxidize (resulting in a
    faded and discolored area matching the label above.)  This migration
    is likely accelerated by higher temperatures and humidities.  The
    problem of adhesive labels and plastic objects plagues the objects
    conservation field.  In particular, Julia Fenn at the Royal Ontario
    Museum in Toronto (Canada) has presented many papers on the problems
    of labeling plastic objects in the museum. Inks and adhesives have
    been known to cause premature cracking, crazing, hazing, corrosion,
    discoloration,...... of these objects.

    I have no answers, but you should know that the problem of labels
    with plastics and metals is well known.


Since this reply I have sent an additional note regarding "dish soap"
and water. For many cleaning jobs that used "dish soap", manufacturers
(in lab procedures) and consequently ANSI recommended "non-ionic
surfactant".  By this, they used to mean Ivory (which they couldn't
really mention by name).  Ivory may once have been a fairly pure
non-ionic surfactant, (ingredients labelling isn't as good in Canada as
it is here in the US) but now it is a mixture of non-ionic, anionic, and
amphoteric surfactants.  In the last few years they have also started
listing "aesthetic agents" on their label.  I don't know how the
formulation changes may affect its "benignity" to things.  Ivory has
generally been one the "purer" detergents on the commercial market
(fewer "other" things.)  It may be better to get something like Triton
X-100 or Nonidet P-40 to try instead.

Depending on the polymer, effects of water may vary.  Some polymers
absorb water easily and tend to swell.  Absorbed water will promote
oxidation of metals as well as possibly adversely affecting adhesion of
layers. Other polymers absorb very little water and will show little
effect.  Glass too may be affected by surfactants and water.  In
general, if water and detergents must be used, commercial preparations
should be avoided, since the exact composition is not known.  Water
should be as pure as possible.  Many chemicals in tap water may cause
damage to polymers and glass or may leave residues.

As usual, this is a rather "sit on the fence and say nothing" answer.

-Doug

                                  ***
                   Conservation DistList Instance 5:4
                   Distributed: Sunday, June 9, 1991
                        Message Id: cdl-5-4-007
                                  ***