SO of course, the question is why is Tyvek getting softer?
I asked one of our SCMRE organic chemists if it was a chemical reaction or
a mechanical one: does the Tyvek get softer because something is leached
during washing or is it being agitated (pulped). Walter Hopwood reports no
chemical reaction by washing but rather deformation of the Tyvek by creep.
You are removing the crimp and elongating the polymer...sort of mashing it;
washing is a convenient method but you could beat it with mallets or flex it
or mash it like grapes. It is not the cleaning but the agitating action of
the washing that softens the Tyvek.
This in turn means that you are changing the (physical) properties of the
Tyvek to meet your (real) requirements--interesting! Mary

Walter Hopwood cites Fibres, Films, Plastics and Rubbers: A Handbook of
Common Polymers compiled by WJ Roff and JRScott with J. Pacitti London:
Butterworths

>>> [log in to unmask] 07/15/03 01:53PM >>>
I have already responded to Ms. Harritt directly, but since there has been
further discussion on the subject, I wanted to repeat the information to the
entire list.

Tyvek gets very soft if it is washed, so that could take care of the
concerns that it is too stiff or sharp. The Costume Institute at the
Metropolitan Museum of Art has been using the Tyvek labels extensively for
14 years. There have not been any problems with them so far. They do not,
however, use a printer, but a Sharpie to write the information on them, so
there hasn't been an issue with melting.

Maya Naunton
Polaire Weissman Fellow
The Costume Institute
Metropolitan Museum of Art