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Will LAST Tape Preservative work on acetate based tape?

CategoriesLAST Tape Preservative
Post date April 3, 2016

Magnetic Tape CareI was reading up on your website about LAST Tape Preservative, and I get the issue with polyester based tape with respect to needing to dehydrate it first before applying your ‘LAST Tape Preservative’. But what about acetate based tape, where dehydration is ill-advised?
Also:

  • Can you apply ‘LAST Tape Preservative’ without any great concern as long as the acetate-based tape is reasonably hydrated? 
  • Once the ‘LAST Tape Preservative’ has been applied (& evaporated for this case), is the sensitivity of acetate based tape any less sensitive to it’s state of hydration?
  • Or is the use of ‘LAST Tape Preservative’ simply not recommended on acetate based tape?

Thanks in advance for the feedback, S.M.

Answer from Walter Davies

Thank you for your letter and your queries.  LAST Tape Preservative is safe and effective for Acetate based tape that is reasonably hydrated.  Historically, acetate tape that has been too heavily hydrated may be subject to the potential for failure of the binder component of the oxide matrix.  If the oxide binder matrix has a moisture content approaching 20%, the binder can begin to disassociate chemically. The disassociation leads to failure and separation from the acetate tape base.  Excessive oxide “rub-off” on guides and heads is an indication of imminent failure of the binder matrix.

Acetate tape that is not adequately hydrated can become sufficiently brittle so as to break and fail at any attempt to pass it through a machine.

The preservation treatment is applied to the oxide matrix. This stabilizes the tape against wholesale diffusion of atmospheric moisture into the matrix itself.  The treatment absorbs into the body of the magnetic matrix, not the acetate backing.  It will not affect the stability or state of hydration of the acetate base material.

Once magnetic tape (acetate or polyester backing) has been treated with preservative, very long term stability of the material  is best achieved by storage under hermetic seal.   This is done to maintain a relatively constant state of relative humidity.  This separates the media from the at-large environment within which atmospheric moisture content (and temperature) are constantly changing.

I hope that this information is helpful. With Best Regards, Walter Davies