Tyvek

Tyvek (TIE-veck) is a brand of flashspun high-density polyethylene fibers, a synthetic material; the name is a registered trademark of the DuPont Company. The material is very strong; it is difficult to tear but can easily be cut with scissors or any other sharp object. Water vapor can pass through Tyvek (Not properly breathable), but not liquid water, so the material lends itself to a variety of applications: medical packaging, envelopes, car covers, air and water intrusion barriers (housewrap) under house siding, labels, wristbands, mycology, and graphics. Tyvek is sometimes erroneously referred to as "Tyvex."

History

Tyvek is a nonwoven product consisting of spunbond olefin fiber. It was first discovered in 1955 by Dupont researcher Jim White who saw polyethylene fluff coming out of a pipe in a DuPont experimental lab. [ [http://www2.dupont.com/Tyvek/en_US/products/about_pgs/history.html Tyvek History - Dupont.com] ] It was trademarked in 1965 and was first introduced for commercial purposes in April 1967. [ [http://repanet.de/Tyvek/en_US/news_events/article20070619.html DuPont Tyvek Marks 40 Years of Energy Efficiency and Protection - June 19, 2007 - repanet.de] ]

According to Dupont's website: the fibers are 0.5-10 µm (compared to 75 µm for a human hair). The nondirectional fibers (plexifilaments) are first spun and then bonded together by heat and pressure, without binders. [ [http://repanet.de/Tyvek/en_US/assets/downloads/tyvek_handbook.pdf Product Handbook for DuPont Tyvek] ]

Properties

*Light weight
*Flammability
*Chemical resistance
*Dimension stability
*Opacity
*Neutral pH

Uses

Tyvek is used by the United States Postal Service for some of its Priority Mail and Express Mail packages. New Zealand has also used it for their driver's licences from 1986 to 1999 [http://www.ltsa.govt.nz/factsheets/54.html] , and Costa Rica [http://au.geocities.com/kai_oceania/costarica252.htm] , the Isle of Man [http://au.geocities.com/kai_oceania/isleofman38.htm] , and Haiti [http://au.geocities.com/kai_oceania/haiti.htm] have made banknotes from it. These banknotes are no longer in circulation and have become collectors items.

Many lightweight backpackers are now using homemade Tyvek groundcloths, finding that they are lighter, cheaper, and pack smaller than the traditional blue plastic tarps.

Tyvek coveralls are one-piece jumpsuits made of Tyvek, usually white in color. They are often worn by mechanics over their clothes to avoid contact with oil and fuel. They can also be worn for painting to protect skin and clothes from splattered paint, for installation of fiberglass insulation, by workers in laboratories and clean rooms, and any other use where a disposable, one-time use coverall is needed. Tyvek coveralls are also used for some light hazardous materials applications but do not provide the level of protection of a full hazmat suit. Tychem is a sub-brand of Tyvek rated for a higher level of protection. DuPont makes Tyvek clothing in different styles from lab coats and aprons to complete head-to-toe coveralls with hoods and booties. In 1976, fashion house Fiorucci made an entire collection out of Tyvek [cite web|url=http://www.fiorucci.it/2004/eng/hp_eng.htm | title=Memoribilia:Fiorucci's Steps | Format=Flash | date=2004 | publisher=Fiorucci Design Office S.r.l. | accessdate=2008-04-29] , while rock band Devo is known for their yellow Tyvek stage wear.

Large sheets of Tyvek are frequently used as "house wrap", to provide a water barrier between the outer cladding of a structure and the frame, insulation, etc. It also serves as a windbreaker. [DuPont: [http://www2.dupont.com/Tyvek_Construction/en_US/?src=tyvek_installation_g Tyvek® Weatherization Systems] ]

Tyvek can also be used to make CD and DVD sleeves, due to its useful properties that give the disc sufficient protection. Netflix in USA, [http://www.glorimedia.de glorimedia.de] in Germany and LOVEFiLM use Tyvek sleeves for posting their rental DVDs.

Tyvek is manufactured at the Spruance plant in Richmond, Virginia, and in Luxembourg.

Recycling

Though Tyvek superficially resembles paper (for example, it can be written and printed on) it is plastic, it cannot be recycled with paper. And despite the fact that some Tyvek products are marked with the #2 resin-code for HDPE, it is not usually collected with plastic bottles as part of municipal curbside recycling programs. Instead, DuPont runs a program in the United States where disposable clothing, coveralls, lab coats, and other Tyvek disposable garments can be recycled, as well as providing a mail-in recycling program for envelopes [http://www2.dupont.com/Tyvek_Envelopes/en_US/tech_info/tech_environ.html] .

References

External links

* [http://www2.dupont.com/Tyvek/en_US/index.html What is Tyvek]
* [http://www2.dupont.com/DuPont_Home/en_US/ DuPont home page]
* [http://www2.dupont.com/NASApp/tyvek/DPPRequestGateway/0/5/?command=ACProductStyleQA&prod=1032 Tyvek FAQ at DuPont]
* [http://www2.dupont.com/Tyvek_Envelopes/en_US/tech_info/tech_environ.html Tyvek Envelope Recycling Program]
* [http://www.materialconcepts.com/products/tyvek/ Tyvek Hard Structure and Soft Structure - What’s the difference?]