Су өткізбейтін, тыныс алатын мата - Gore-Tex технологиясы

Trademark for a waterproof, breathable fabric

Gore Tex is W. L. Gore & Associates's trade name for waterproof, breathable fabric membrane. It was invented in 1969. Gore Tex blocks liquid water while allowing water vapor to pass through and is designed to be a lightweight, waterproof fabric for all weather use. It is composed of expanded PTFE (ePTFE), a stretched out form of the PFAS compound polytetrafluoroethylene (PTFE). Gore Tex products free of "PFC of environmental concerns" repellent coating lacks the ability to repel oil that "Gore DWR" provided.

ePTFE has a porous microstructure composed of long, narrow fibrils that intersect at nodes. Increasing the processing temperature or increasing the strain rate leads to more homogenous expansion with more spherically symmetric pores and more intersections between fibrils. The formation of ePTFE is enabled by the unwinding of PTFE molecules to create large pores within the structure. This favors highly ordered, crystalline PTFE that allows the molecules to disentangle more easily and uniformly when stretched. The porosity is largely determined by the stretching temperature and rate. Changing the stretching rate from 4.8 m/min to 8m/min can increase the porosity from 60.4% to 70.8%.

Due to the high work hardening rate of PTFE, ePTFE is significantly stronger than the unstretched material. On a microscopic level, this work hardening corresponds to the increasing crystallinity of PTFE as the fibrils untangle and orient upon the application of an external stress. ePTFE has a strikingly high ultimate tensile strength (50 800 MPa) relative to its full density counterpart (20 30 MPa) as a result of its high crystallinity. This behavior also yields a negative Poisson's ratio due to the expansion of ePTFE along all directions, contrasting the more expected reduction in the directions perpendicular to the stress in cases with volume conservation. a persistent environmental contaminant. The International Agency for Research on Cancer has classified PFOA as carcinogenic to humans. Gore pledged in 2017 to eliminate PFCs such as PFOA by 2023, although the core technology will continue to be based on PTFE, which is a PFAS compound. Many Gore Tex products have a durable water repellent coating and the version that do not contain PFCs of environmental concerns are marketed as "Gore PFCEC Free DWR". Unlike the "Gore DWR", it lacks any form of oil repellency. The company intends to replace ePTFE membrane with expanded polyethylene membrane by 2025 in consumer fabrics. The new material, while intended to perform comparably to the existing ePTFE material, will cost more, and require more frequent washing.

Two lawsuits have been filed against Gore on the matter of PFAS related water pollution around its Cecil County, Maryland manufacturing plant and the Maryland Department of the Environment has ordered an investigation and residents in the monitoring area have been offered bottled water. One of the lawsuits alleges that the company knew about the dangers of PFOA/PFAS since the 1990s.

Gore Tex materials are typically based on thermo mechanically expanded PTFE 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 fabric is best known for its use in protective, yet breathable, rainwear.

Before the introduction of Gore Tex, the simplest sort of rainwear would consist of a two layer sandwich, where the outer layer would typically be woven nylon or polyester to provide strength. The inner one would be polyurethane (abbreviated: PU) to provide water resistance, at the cost of breathability. Early Gore Tex fabric replaced the inner layer of non breathable 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 more volatile water vapor molecules to pass through. The outer layer of Gore Tex fabric is coated on the outside with a Durable Water Repellent (DWR) treatment. The DWR prevents the main outer layer from becoming wet, which would reduce the breathability of the whole fabric. However, the DWR is not responsible for the jacket being waterproof. Without the DWR, the Gore Tex layer would become soaked, thus preventing any breathability, and the wearer's sweat being produced on the inside would fail to evaporate, leading to dampness there. This might give the appearance that the fabric is leaking when it is not. Wear and cleaning will reduce the performance of Gore Tex fabric by wearing away this Durable Water Repellent (DWR) treatment. The DWR can be reinvigorated by tumble drying the garment or ironing on a low setting. Gore 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, and it can stretch, but it is not waterproof. The Gore naming system does not imply any specific technology or material but instead implies a specific set of performance characteristics.

Expanded polytetrafluoroethylene is used in clothing due to its breathability and water protection capabilities. Besides use in rainwear ePTFE can now be found in space suits.

Gore Tex is also used internally in medical applications, because it is nearly inert inside the body. Specifically, expanded polytetrafluoroethylene (E PTFE) can take the form of a fabric like mesh. Implementing and applying the mesh form in the medical field is a promising type of technological material feature. In addition, the porosity of Gore Tex permits the body's own tissue to grow through the material, integrating grafted material into the circulation system. Gore Tex is used in a wide variety of medical applications, including sutures, 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 been shown to be a reliable synthetic, medical material in treating patients with nasal dorsal interruptions. In more recent observations, expanded polytetrafluoroethylene (E PTFE) has recently been used as membrane implants 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 leading to the sensitive voltametric detection of nitroaromatic compounds. The "Gore Tex" brand name was formerly used for industrial and medical products. Gore Tex has been used since the 1980s to make bagpipe (woodwind instrument) bags as an alternative to bags made of animal hides as it was able to hold air while allowing moisture to escape, and did not degrade with exposure to water.