Gore-Tex is a waterproof, breathable membrane fabric and registered trademark of W. L. Gore and Associates. Invented in 1969, Gore-Tex was able to resist liquid water while allowing water vapor to be bypassed, and designed to be a lightweight and waterproof fabric for all-weather use. It consists of stretch polytetrafluoroethylene (PTFE), better known as Teflon general trade name.
Video Gore-Tex
History
Gore-Tex was co-created by Wilbert L. Gore and Gore's son, Robert W. Gore. In 1969, Bob Gore stretched hot rods from polytetrafluoroethylene (PTFE) and created an expanded polytetrafluoroethylene (ePTFE). His discovery of the right conditions for PTFE stretching was a happy accident, born partly from frustration. Instead of stretching the slowly heated material, he immediately swung panting. Dense PTFE suddenly stretches about 800%, forming a micro structure that is about 70% air. It was introduced to the public under the Gore-Tex trademark.
Bob Gore immediately applied and obtained the following patents:
- AS. Patent 3,953,566, published on 27 April 1976, for a porous form of polytetrafluoroethylene with a microstructure characterized by interconnected nodes by fibrils
- AS. Patent 4,187,390 , issued 5 February 1980
- AS. Patent 4,194,041 on March 18, 1980 for "waterproof laminate", together with Samuel Allen
Another form of the stretched PTFE ribbon was produced before Gore-Tex in 1966, by John W. Cropper of New Zealand. Cropper has developed and built machines for this use. However, Cropper chose to keep the creation process of PTFE expanded as a trade secret that is held firm and thus, it remains unpublished.
In the 1970s Garlock, Inc. allegedly infringing Gore's patents by using Cropper machines and sued by Gore in the Ohio District Court of Ohio. The District Court held Gore's product and process patents invalid after a "heavily debated case" involved "two years of discovery, five weeks of trial, testimony of 35 witnesses (19 lives, 16 by deposition), and over 300 exhibits" ( citing the Federal Circuit). On appeal, however, the Federal Circuit disagrees in the famous case of Gore v. Garlock , reversing lower court decisions on the ground, as well as others, that Cropper lost superior claims of discovery by Priority had concealed the process of making ePTFE public. Since a public patent has not been filed, a new form of the material can not be legally recognized. Gore is therefore the founder of the law of ePTFE.
Following the decision of Gore v. Garlock, Gore sued Bard, Inc. for allegedly infringing his patent by making ePTFE vascular grafts. Bard immediately settled and agreed to get out of the market. Gore next sued IMPRA, Inc., a smaller maker of ePTFE vascular grafts, in a federal district court in Arizona. IMPRA has a patent application that competes for ePTFE vascular grafts. In battle for most of the decade/antitrust (1984-1993), IMPRA proves that Gore-Tex is identical to the prior art expressed in Japanese patent processes by duplicating the previous art process and through statistical analysis, and also proves that Gore has concealed the best modes to use patents and major claims of Gore product patents declared invalid in 1990. (See WL Gore & Assoc., Inc. v. IMPRA, Inc., 975 F.2d 858 (Fed Cir 1992)). In 1996, IMPRA purchased by Bard and Bard could thus reenter the market. After IMPRA vascular graft patent was issued, Bard sued Gore for violating the right. In 2015, Gore was ordered by the Federal Circuit Court of Appeal to pay Bard $ 1 billion in damages. The US Supreme Court refused to review the decision of the Federal Circuit.
Gore-Tex is used in products manufactured by Patagonia, L.L. Bean, Oakley, Inc., Galvin Green, Marmot, Vasque, Outdoor Research, Arc'teryx, HaglÃÆ'¶fs and The North Face.
Since the end of Gore-Tex's main patent, several other products have come to the market with similar characteristics using similar technology. As a cheaper alternative to more expensive membranes, there is also a less durable waterproof/breathable layer.
For his discovery, Robert W. Gore was inducted into the US National Inventor Hall of Fame in 2006.
Maps Gore-Tex
Producing
PTFE is made using emulsion polymerization process using PFOA fluorosurfactant which is carcinogenic, persistent environmental contaminant. In 2013, Gore abolished the use of PFOA in the manufacture of weatherproof functional fabrics.
Design
The Gore-Tex material is usually based on expanded PTFE-thermo-mechanical and other fluoropolymer products. They are used in a wide range of applications such as high-performance fabrics, medical implants, filter media, insulation for wires and cables, gaskets, and sealants. However, the Gore-Tex fabric is best known for its use in a protective, yet breathable, raincoat.
The simplest type of rainwear is a two-ply sandwich. The outer layer is usually nylon or polyester and gives strength. The inside is polyurethane (abbreviated: PU), and provides water resistance, with breathability costs.
Early Gore-Tex fabrics replace the inner layers of PU with a thin porous membrane fluoropolymer (Teflon) membrane bonded to the fabric. This membrane has about 9 billion pores per square inch (about 1.4 billion pores per square centimeter). Each pore is approximately 1/20,000 the size of a water droplet, making it impenetrable by liquid water while still allowing more volatile water vapor molecules to be passed.
The outer layer of Gore-Tex fabric is coated on the outside with Water Resistant treatment (DWR). The DWR prevents the main outer layer from becoming wet, which will reduce the overall breathability of the fabric. However, DWR is not responsible for waterproof jackets - this is a common misconception. Without the DWR, the outer layer will become wet, there will be no breathability, and the user's sweat produced on the inside will fail to evaporate, causing moisture there. This may give the impression that the fabric is leaking when in fact it is not. Wear and cleaning will reduce the performance of Gore-Tex fabrics using this Water-Resistant (DWR) treatment. DWR can be revived by drying garments or ironing with low settings.
Gore requires that all garments made of their material have bandaged the seams, to remove leaks. Gore's sister product, Windstopper, is similar to Gore-Tex because it is windproof and breathable, but has the ability to stretch and not hold water. The Gore naming system does not imply a particular technology or material, but a set of specific performance characteristics.
Other uses
Gore-Tex is also used internally in medical applications, because it is almost inert in the body. In addition, Gore-Tex porosity allows the body's own tissues to grow through the material, integrating the material grafted into the circulatory system. Gore-Tex is used in a wide range of medical applications, including stitches, vascular grafts, heart patches, and synthetic knee ligaments, which have saved thousands of lives. In the form of expanded polytetrafluoroethylene (E-PTFE), Gore-Tex has recently been used as a membrane implant for glaucoma surgery.
Gore-Tex has been used for many years in the conservation of illuminated manuscripts.
Explosive sensors have been printed on Gore-Tex clothing that leads to the detection of voltammetric sensitive nitroaromatic compounds.
Gore-Tex is also used as a membrane in a sealed battery product, to allow the release of pressure from outgassing, but prevents moisture from entering.
The brand name "Gore-Tex" was previously used for industrial and medical products.
See also
- The Cold Weather Clothes System Extended
- SympaTex
- Windstopper
- Hipora
References
External links
- Official website
- The gore website
Source of the article : Wikipedia
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