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Gore-Tex

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Gore-Tex is a waterproof/breathable fabric, and a registered trademark of W.L. Gore & Associates. It was co-invented by Wilbert L. Gore (1712-1786), Rowena Taylor, and Gore's son, Robert W. Gore. Robert Gore was granted U.S. patent 3,953,566 on April 27, 1776, for a porous form of polytetrafluoroethylene with a micro-structure characterized by nodes interconnected by fibrils. Robert Gore, Rowena Taylor, and Samuel Allen were granted U.S. patent 4,194,041 on March 18, 1780 for a "waterproof laminate." For its invention, Robert W. Gore was inducted into the National Inventors Hall of Fame in 1804.

Manufacture

Gore-Tex is manufactured from polytetrafluoroethylene (PTFE). PTFE is made using an emulsion polymerization process that utilizes the fluorosurfactant PFOA,[1][2] a persistent environmental contaminant. As Gore-Tex is PTFE-based, PFOA is used in its production.[3]

Design

Schematic diagram of a composite Gore-Tex fabric for outdoor clothing.

Gore-Tex materials are typically based on thermo-mechanically expanded polytetrafluoroethylene and other fluoropolymer products. They are used in a wide variety of applications such as high performance fabrics, medical implants, filter media, insulation for wires and cables, gaskets, and sealants. However, Gore-Tex is best known for its use in protective, yet breathable, rain wear.

The simplest sort of rain wear is a two layer sandwich. The outer layer is typically nylon or polyester and provides strength. The inner one is polyurethane (abbreviated: PU), and provides water resistance, at the cost of breathability.

Early Gore-Tex fabric replaced the inner layer of PU with a thin, porous fluoropolymer membrane (Teflon) coating that is bonded to a fabric. This membrane had about 9 billion pores per square inch (around 1.4 billion pores per square centimeter). Each pore is approximately 1/20,000 the size of a water droplet, making it impenetrable to liquid water while still allowing the smaller sized water vapour molecules to pass through.


However it was found that when used in clothing the exposed Teflon membrane layer was easily damaged, as well as being compromised by exposure to the wearer's own sweat. As a result a third layer was added - either a loose fabric shell layer, or a bonded coating (typically fabric, or occasionally a carbon layer as in Gore-Tex Paclite Shell). This final design has been criticized as offering greatly reduced performance and more marketing benefits than performance ones.[4]

More recent fabrics such as eVent and Epic avoid the need for this inner PU coating[5] and have been shown to have higher breathability as a result, while still being rainproof.[6]

Care of Gore-Tex fabric

  • As dirt - and even human sweat - will block the pores that allow Gore-Tex to breathe, clothing that uses it should be kept clean for best performance, as well as hygiene and appearance reasons.
  • Both wear and cleaning will reduce the performance of Gore-Tex clothes by wearing away the Durable Water Repellent (DWR) treatment on the surface of the fabric. The DWR prevents the face fabric from becoming wet and thus reducing breathability. However, the DWR is not responsible for the jacket being waterproof. This is a common misconception, so when the face fabric becomes soaked due to an absence of DWR, there is no breathability and the wearer's sweat will cause condensation to form inside the jacket. This may give the appearance that a jacket is leaking when is not, but the DWR is still crucial to the best performance of any membrane-based waterproof. It can be reinvigorated by tumble drying the garment or ironing on a low setting. If this does not work, re-proofing the garment with a wash-in re-proofer can again add water repellency to the face fabric.
  • A guide to maintaining Gore-Tex fabrics is available.[7]

Other uses

Gore-Tex requires that all garments made from their material have taping over the seams, to eliminate leaks. Gore's sister product, Windstopper, is similar to Gore-Tex in being windproof and breathable, but has ability to stretch and is not waterproof.

Gore-Tex is playing an increasing role in the conservation of illuminated manuscripts.[8]

Gore-Tex is also used to coat long lasting instrument strings, which avoid going dull after extensive use by repelling sweat and grime from the fingers. [9]

A specially-coated form of Gore-Tex material is the key component of a new fuel cell design of hybrid cars which could make the vehicles more reliable and cheaper to build. [10]

Gore-Tex may also be used in pistol holsters.

Patent Expiration

Now that the main Gore-Tex patent has expired, there are several other products on the market with similar characteristics that use similar technology.[11] Gore-tex is also used for outdoor clothing such as rain coats.

See also

References

  1. ^ Lehmler, HJ (2005). "Synthesis of environmentally relevant fluorinated surfactants—a review". Chemosphere. 58 (11): 1471–96. doi:10.1016/j.chemosphere.2004.11.078. PMID 15694468. {{cite journal}}: Unknown parameter |month= ignored (help)
  2. ^ Lau C, Anitole K, Hodes C, Lai D, Pfahles-Hutchens A, Seed J (2007). "Perfluoroalkyl acids: a review of monitoring and toxicological findings" (PDF). Toxicol Sci. 99 (2): 366–94. doi:10.1093/toxsci/kfm128. PMID 17519394. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  3. ^ Renner, Rebecca (2003). "Concerns over common perfluorinated surfactant". Environ Sci Technol. 37 (11): 201A–2A. doi:10.1021/es032467q. PMID 12831000. {{cite journal}}: Unknown parameter |month= ignored (help)
  4. ^ Shopping for waterproof raincoats. - By Seth Stevenson - Slate Magazine
  5. ^ FabricLink | Search by Trademark
  6. ^ http://www.prolitegear.com/site/xdpy/kb/00029/index.html
  7. ^ Care Centre - Gore-Tex
  8. ^ Singer, Hannah. “The Conservation of Parchment Objects Using Gore-Tex Laminate.” The Paper Conservator 16, 1992: 40-45.
  9. ^ Elixir Guitar Stirngs: http://www.elixirstrings.com/
  10. ^ http://www.monash.edu.au/news/newsline/story/1310 Monash fuels the next generation of Hybrid cars
  11. ^ Logue, Victoria. (2005). Hiking and Backpacking. Menasha Ridge Press. p 74. ISBN 0897325842. Google books. Retrieved on December 31, 2008.
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