Tyvek Envelopes

Tyvek is a brand of flashspun high-densityservice for some of its Priority Mail and Express
polyethylene fibers. Tyvek is the name is aMail packages. New Zealand used it for its driver's
registered trademark of DuPont. The material islicenses from 1986 to 1999, and Costa Rica, the
very strong and is difficult to tear but can easilyIsle of Man and Haiti have made banknotes from
be cut with scissors or any other sharp object.it. These banknotes are no longer in circulation and
Water vapor can pass through Tyvek easilyhave become collector items. Some backpackers
making it highly breathable but stops liquid water.are now using homemade Tyvek ground cloths,
The material lends itself to a variety offinding that they are lighter, cheaper, and pack
applications including medical packaging, tyveksmaller than polypropylene tarpaulins.
envelopes, car covers, air and water intrusionTyvek coveralls are one-piece garments made of
barriers, labels, wristbands, mycology, andTyvek, usually white in color. They are often
graphics. Tyvek is sometimes erroneously calledworn by mechanics over their clothes to avoid
Tyvex.contact with oil and fuel. They can also be worn
Tyvek is a nonwoven product consisting offor painting to protect skin and clothes from
spunbond olefin fiber. It was discovered bysplattered paint, for installation of fiberglass
DuPont researcher Jim White in 1955 who sawinsulation, by workers in laboratories and
polyethylene fluff coming out of a pipe in acleanrooms, and any other use where a
DuPont experimental lab. In 1965 it wasdisposable, one-time use coverall is needed. Tyvek
trademarked and was first introduced forcoveralls are also used for some light hazardous
commercial purposes in 1967.materials applications, but do not provide the level
According to DuPont, the fibers are justof protection of a full hazmat suit. Tychem is a
0.5–10 µm compared to 75 µm for a singlesub-brand of Tyvek rated for a higher level of
stand of human hair. The nondirectional fibersprotection. DuPont makes Tyvek clothing in
called plexifilaments are first spun and thendifferent styles from laboratory coats and aprons
bonded together by pressure and heat.to complete head-to-toe coveralls with hoods and
Tyvek is used by the United States postalboots.