The Book and Paper Group
Annual
VOLUME ELEVEN 1992
The American Institute for Conservation
The history of Gore-Tex started in 1958 when Wilbert Gore identified a market opportunity for polytetrafluoroethylene, or PTFE. This is better known to us as DuPont Teflon. His idea was to use it as insulation for electronic wires. Mr. Gore and his wife set up shop in the basement of their home to make PTFE-insulated ribbon cables.
In 1969, Mr. Gore's son Bob discovered that PTFE could be stretched to form a strong, porous material. This discovery came after long experimentation using high temperature and a slow stretching technique. Perhaps in frustration, the high temperature and FAST STRETCH production secret was discovered. the unique properties of this material have led to a wide variety of applications. It was patented and has the trademark GORE-TEX.
Gore-Tex expanded PTFE is chemically inert. It has a low friction coefficient, which means it is smooth to the touch. It functions over a wide temperature range and has good aging qualities. It is porous, air permeable, strong, hydrophobic, biocompatible and weather durable.
Gore-Tex is PTFE that has been processed into new physical forms. PTFE, or polytetrafluoroethylene, is a polymer called a perfluorocarbon resin. in perfluorocarbon resins, all of the carbon atoms in the backbone of the polymer chain are fully bonded to fluorine atoms. the carbon to fluorine bond (C-F bond) is such a strong bond that neither oxygen nor ultraviolet light are sufficiently energetic to break it. the strength of this bond is the source of chemical inertness and good aging properties. Gore-Tex has undergone tests that show it will last more than 100 years in outdoor exposure. the strength of the C-F bond is also the reason the Gore process for PTFE is possible. the strings that connect the larger areas of PTFE together in this micrograph are directly related to the strength of the C-F bond in the molecule.
The distribution of the fluorine atom" around the carbon polymer backbone balances the electronegative and electropositive charges, making PTFE non-polar. Non-polar materials are not attractive to polar substances, like water. This fully fluorinated polymer has a low surface energy which causes it to be nonwettable by water. PTFE can withstand temperatures from -240 to +280 degrees centigrade. No solvating agent is known for PTFE.
The production of ribbon cable was the first Gore commercial venture. Even though Wibert Gore imagined his new material as an insulator for wires, now pure Gore-Tex wires are used in some situations. PTFE has outstanding electrical properties and is chemically inert. Gore-Tex, porous PTFE, retains the electrical properties of that material but is also lightweight. That is possible because electricity can move through the Gore-Tex as well as it moves through the air pockets in the Gore-Tex. These wires are lightweight and transmit electricity very fast and are used in aircraft and satellites. Gore wire and cable can withstand the heat of ignition and the cold of space. on the moon, the same cables are in seismic instruments and rock-collecting shovels.
These Gore products are truly space-age materials, and yet they are used in many earthbound ways. Gore cables enable computers to transmit signals at nearly the speed of light. They are used in computer printers, underground in oil drilling operations and undersea in submarines. They are also made into tiny forms for miniature brain probe cables.
Gore-Tex expanded PTFE is also used as a replacement for human tissue. Portions of arteries can be replaced by tubes of this material because it is strong, biocompatible and able to carry blood at arterial pressures without leaking. Gore-Tex vascular grafts have been implanted in patients of all ages, and are used in practically every part of the body.
Another use for Gore-Tex expanded PTFE is a" an implant material. After more than 700,000 clinical uses, there are no confirmed cases of material rejection. These soft tissue "patches., as they are called, provide the strength and thickness required for the most demanding soft tissue repairs. the suppleness of the material makes it easy to work with in difficult reconstructions. the softness of the material assures patient comfort. the structure of the material does not fray so the surgeon can sew the patch into place more easily. These soft tissue patches have been used to repair both heart and stomach tissue.
Micro porous Gore-Tex expanded PTFE is a biocompatible structure into which cells can penetrate. This material is incorporated into the surrounding tissue, not encapsulated by it. This incorporation by the surrounding tissue may be the reason there is such a low incidence of infection after these implants.
During the slide presentation at the A.I.C. meeting, a micrograph was shown of another implant material, not Gore-Tex, where the implant fibers are distinctly separate from the surrounding tissue cells. the other implant material had not been incorporated into the living tissue. Another micrograph of a Gore-Tex implant was shown in which the cells had been able to grow throughout the structure of the Gore-Tex pores. It had been incorporated into the living tissue.
Another Gore-Tex material has also been used to replace ligaments in knee surgery. This material of is produced in such a way as to provide the majority of its strength in the longitudinal direction because that is where it is needed. Gore-Tex makes medical sutures that handle like silk, have extreme strength and allow for tissue attachment. These are available on special cards that release the thread without snagging or knotting. Gore-Tex also makes threads in a variety of sizes.
New composite materials made by Gore are being used in printed circuit boards for computers. the Gore company does research in polymer science that has resulted in new adhesives, sealants and coatings. Gore-Tex is used in a variety of protective clothing. in some instances they can replace vinyl or rubber suits and because of its breathability provide greater comfort. Clean room garments are made of this fabric and could be worn by conservators in situations were dirt, water or mold are serious problems. Gore-Tex can be heat sealed. This makes an infinite number of shapes possible. in addition to the fabric used for these garments, a new stretch Gore-Tex fabric is also now available.
Another material used by industries is the Gore-Tex valve stem packing material. This material may be a solution to some packing problems. the microporous nature of Gore-Tex has led to extensive filtration applications. It has been used for filtration in industry to reduce air pollution. It can filtrate plant gas streams containing corrosive chemicals like sulfuric acid and strong alkaline solids. Those interested should contact W.L. Gore and Associates through the information given at the beginning of this article.
In paper conservation, we use a specific form of Gore-Tex. We use laminates of Gore-Tex expanded PTFE film and nonwoven fabrics. the nonwoven fabric used is made by Dupont and called "Sontara". Sontara spunlaced fabric is a textile composed of fibers entangled in an unbonded structure. There are no resin binders or interfiber bonds in the fabric. Sontara is composed of 100% polyester fiber. Sontara is similar in breaking strength to finished cotton sheeting and has good resistance to tearing. It retains approximately 75% of its strength when wet. the following classes of compounds have little or no effect on the strength of Sontara: alcohols, halogenated hydrocarbons, ketones, or water. Benzene does cause a moderate strength loss. Sontara has a good resistance to aqueous solutions of acids and alkalis.
The Sontara fabric is bonded to the Gore-Tex film with a process that includes heat, so no additional adhesive is in the material we use. It is composed only of a thin film of Gore-Tex that has been attached to the fabric Sontara. White Gore-Tex, it should be noted, has no colorants in it. Pigments can be added to Gore-Tex to color it but white is the color of the basic material.
Conservators are often faced with the problem of evaluating substitutes for materials. There is a material that is similar to Gore-Tex expanded PTFE, but is not an acceptable substitute. That material is polyvinyl difluoride, or PVDF. It is a fluoropolymer and the carbon chains in fluoropolymers are not completely fluorinated. Some of the carbons, up to 50%, are bonded to halogens or hydrogen. the presence of hydrogen makes the PVDF susceptible to dehydrohalogenation, or the removal of hydrogen and halogens from adjacent carbons in the chain giving off chemically active materials. This increases the potential for degradation. Also, PVDF is soluble in some conventional solvents.
The graphs on the following pages show the greater stability of Gore-Tex, or PTFE, versus PVDF. Gore-Tex is resistant to all the solvents on these lists and PVDF is not.
Regarding solvent use with Gore-Tex, quick tests to determine if only the vapors of a solution will penetrate Gore-Tex can be done. As an example, a drop of water sits on top of Gore-Tex. in comparison, a drop of ethanol immediately penetrates the Gore-Tex surface. a 10% mixture of ethanol and water will change the properties of water for use with Gore-Tex. the percentage could be smaller, so be sure to test any solutions before you use them.
Ethanol is only slightly less polar than water compared to many organic solvents, so all organic solvents will penetrate Gore-Tex. If you use Gore-Tex with solvents, and the previous charts showed you can do that safely, you may not necessarily be using solvent vapors. Do not rule out Gore-Tex use with solvents, however. the Gore-Tex allows a controlled application of solvent and that can be extremely useful.
With regard to enzymes, I would also like to note that I have been informed that the pore size in the Gore-Tex laminates would allow enzyme solutions to pass through the pore-, once the surface tension with the aqueous solution is broken. Breaking that surface tension could be a procedure that involves using ethanol immediately before applying water. This type of procedure has not, to my knowledge, been applied yet in a conservation treatment.
The second part of this paper will discuss some ways Gore-Tex has been used in treatments at the Conservation Center for Art and Historic Artifacts.
Chemical Compatibility GuideThis information and the micrograph on the first page are courtesy of W.L Gore and Associates, Inc.
MT/cp 5/15/90
Rl - Use up to 135ºC
R2 - Use up to 75°C
®Teflon :s a registered trademark of E. I. du Pont de Nemours & Co., Inc.
Table from Fisher Filtration Catalogue, 1985 Fisher Scientific
Gore-Tex has been used in many area. of conservation, and although there have been innovative uses of Gore-Tex by other conservators, I will only be discussing treatments done on paper and parchment at the Conservation Center for Art and Historic Artifacts.
The most useful characteristic of Gore-Tex is its versatility for humidity control. When used correctly, it can evenly humidify an object in an incredibly delicate manner, and at the same time it gives you a greater amount of control of this humidity.
Here are some ways the humidification function and other unique characteristics of Gore-Tex can be applied.
Gore-Tex can be used:
The basic sandwich set-up for humidification of objects using Gore-Tex:
Plastic cover sheet or mylar -Damp blotter -Gore-sex (smooth side against object) -Object -Gore-Tex (smooth side against object)
Throughout this paper, unless otherwise noted, I will be referring to Gore-Tex used in this way.
Care should be taken when handling the Gore-Tex material. It is an expensive and delicate fabric that can be easily creased or punctured.
Do not use excess weight, like glass or weights on top. Too much pressure will force water through the membrane. Liquid water can also penetrate at cracks and holes. If the artifact must be held in plane, only use as much weight on top a. necessary to achieve this; a felt or a piece of Plexiglas will do.
To humidify an object use damp or humid blotters, or lightly spray the felt side of the Gore-Tex. Be sure to check your object often, at least every fifteen minutes. Although Gore-Tex usually humidifies slowly, some objects tend to get damp quickly. If after an hour or two you feel you need more moisture to get the desired humidification results, spray the blotters again. Remember, 100% humidity is water. a saturation point can be reached by using too much water or weight with Gore-Tex. Saturated blotters are excessive.
Once one becomes familiar with the way Gore-Tex works, the different components can be changed. for example, to humidify an object from one direction, remove the top or bottom two layers of blotter/Gore-Tex. Or, create a small vapor chamber by placing a mylar or Plexiglas box over an object covered with Gore-Tex and place a damp blotter inside the enclosure. the porous interior structure of Gore-Tex will evenly diffuse the humidity.
Before treatment, careful testing of supports and media with small pieces of Gore-Tex is recommended. the following treatments are some examples where Gore Tex performed as an indispensable tool.
The first treatment I will discuss is an Italian, eighteenth century gouache painting of Mount Vesuvius on wove paper. the support had severe planar distortion and was very dry and brittle. the objective was to humidify this piece very, very slowly, so that the media and paper would expand at the same rate. a more conventional means of humidification might have cracked the media.
The painting was humidified in the Gore-Tex pack over an eight hour period with barely damp blotters. It was then allowed to dry slowly in the Gore-Tex pack replacing the damp blotters with dry. Not only was the distortion in the support of the painting reduced, but the paper was much more flexible. the media was undisturbed (Figure 1 and 2).
If an object shows evidence of mold, this might not be the best method of humidification. Be sure to check an object frequently when humidifying it, both for mold and the degree of dampness of the object.
The second treatment is a Mickey Mantel baseball card, an offset lithograph on laminated card stock. There was a deep crease across the top right corner. Collectors of baseball cards will know, that the better the condition, the more valuable the card is.
After trying local applications of humidity and Ethulose to reduce the crease, Gore-Tex was finally tried and the card humidified overall. the crease was then lightly pressed down with a bone folder through silicon release mylar. It was then flattened between the hard surface of mat boards. I believe this worked because all the layers of the card were equally humid, allowing the broken fibers to be pushed back into place.
Here are the components of the Gore-Tex set-up I used: Gore-Tex, damp blotters, mylar cover sheet. and weights (Figure 3).
A good example of local humidification using Gore-Tex are these drawings of battle scenes. They were done with iron gall ink on thin, blue wove writing paper by a Blackfoot Indian chief, c. 1850. the drawings were originally bound by Jesuit missionaries. They were disbound recently for exhibit purposes. the sections, adhered together with water soluble adhesive, had to be separated. There were about seven folios adhered together in each section. the sensitivity of the iron gall ink and the surface coating of the paper prohibited water immersion. Methylcellulose was tried first as a poultice to introduce moisture, but by the time the adhesive softened, the paper was too wet to safely separate the folios.
Small pieces of Gore-Tex and damp blotter strips were used to just cover the central adhered area (Figures 4 and 5). the adhesive became soft enough so that the folios could be separated one by one, replacing the Gore-Tex set up each time. By the time the adhesive was removed mechanically from one folio, the next one adhered in the section was ready to be lifted off, that is, the adhesive was moist enough to release it.
Gore-Tex is also very useful in backing removals. This early twentieth century lithograph poster printed on thin wove paper was adhered to a thick cardboard support (Figure 6). in this case, the use of the Gore-Tex pack allowed the composite elements of the poster and the multilayered backing to slowly humidify overall. the poster and backing were then equally expanded when placed in a bath, where the two were separated. Therefore, there was no fast expansion where the possibility of tearing in the primary support could occur.
In another case, a large (5'x 5') printed (lithograph) map with hand coloring on very thin wove paper had a cardboard backing twice as thick and dense as this one. Almost all the colors were soluble with water when tested. Removing it mechanically with a scalpel proved extremely difficult because the cardboard was very dense.
Gore-Tex was used to humidify the map in order to soften the board. the backing could then be pared off easily in sheets saving an enormous amount of time. the media was undisturbed.
Because Gore-Tex disperses humidity so evenly, it is an effective tool to humidify parchments. After humidifying a parchment in the Gore-Tex sandwich it can be put on the suction table for flattening and drying. Wrinkles can gently be pulled out while it is under tension, and can be pressed out with a bone folder through mylar. Mylar strips have to be used at the edges of the parchment while it is on the suction table to hold it down. When the parchment is sufficiently flat, it is covered with Gore-Tex, which acts as a barrier holding it down on the suction table and allowing air to flow through at the same time to dry the parchment.
Figure 7 shows a very large map, approximately 4'x 5', of early eighteenth century Lancaster, Pennsylvania. It was drawn with iron gall ink and gouache with graphite sketches around the borders. the support is made up of four pieces of parchment unequal in size and degree of thickness which are sewn and adhered together. It had been stored folded in many sections.
The treatment proposal called for it to be humidified and flattened. the concerns in the humidification steps were: the sensitivity of the media to moisture, evenly humidifying the different thicknesses of parchment, and how the adhered and sewn areas would react.
After mending tears and consolidating the media, a small area of the map was tested with Gore-Tex before it was humidified overall (Figure 8). It proved very successful; all areas were evenly humid and relaxed including the adhered and sewn parts. the media did not appear affected by the introduction of humidity.
Because it was such a large object and the suction table dries objects so quickly, the center of the table was blocked off with Mylar with the intention of drying and stabilizing the edges of the parchment first. Later, when the edges were somewhat dry, the suction table was turned off and the center mylar pulled out. the machine was turned back on, then allowing the entire map to be manipulated and dried as described above (Figure 9).
This is an example where Gore-Tex served several functions during a treatment.
This is a 4 x 8 foot painting in gouache of the Minoan frescos at Knossos on heavy, machine-made wove paper dating from the beginning of this century (Figure 10). It had a 1/2 inch thick, brittle, acidic multilayered paper board backing. It had fallen and broken in two in storage. Although treatment was very complicated, it basically consisted of surface cleaning, consolidation of media, backing removal (mechanical), mending tears and drop lining.
The painting was extremely discolored and could not be washed because of the water soluble media, but it had to be lined. When it was lined, the concerns then were the possibilities of staining in the unwashed and discolored painting from the wet lining, and of planar distortion while drying. We believed if we limited the humidity during the treatment and slowed down the drying process, we could control both.
The basic Gore-Tex set-up I described earlier was used in this treatment, but we altered it slightly by placing the object face down on Pelon and then the Gore-Tex. This arrangement allowed us to humidify, line and partially dry the object without turning it over. Because of its large size and fragility, we wanted to move the object as little as possible. the painting stayed between the Gore-Tex for the rest of the treatment. This greatly facilitated the handling of the object.
After humidifying it with Gore-Tex in preparation for lining, the top Gore-Tex sheet was partially rolled back to drop line the painting in sections, keeping the rest of the artwork humid at the same time.
After the initial immediate blotter changes, when the painting was almost completely dry and stronger, we turned it over. the table was tented with plastic to keep some humidity in and it was slowly dried over a period of a week until it was dry and flat (Figure 11). No distortion or staining in the support resulted. We believe the Gore-Tex made this treatment possible.
To close, I want to mention a few other Gore-Tex uses in treatments we have Performed at the Conservation Center:
I hope these examples show how versatile a tool Gore-Tex can be in paper conservation treatments. Perhaps they will be an inspiration for uses in other diverse ways.
Gore-Tex fabrics are produced by
Nancy PurintonW.L. Gore and Associates, Inc. 100 Airport Rd.
P.O. Box 1550
Elkton, MD. 21922-1550
(301) 392-4440
Contact: Lowell R Perkins
Received: Fall 1992
Paper delivered at the Book and Paper specialty group session, AIC 20th Annual Meeting, June 2-7, 1992, Buffalo, NY.
Papers for the specialty group session are selected by committee, based on abstracts and there has been no further peer review. Papers are received by the compiler in the Fall following the meeting and the author is welcome to make revisions, minor or major.
Anika Williamms
DES 040A
March 15, 2023
Gore-Tex Raw Materials Paper
Introduction
Gore-Tex is a textile which is widely used in the outdoor outerwear sector, renowned for its highly desirable waterproof, windproof and durable qualities. It is produced by the company Gore and cautiously licensed to vendors who are able to prove their methods of using the textile will keep Gore-tex products held in high regard by its customers. It can be readily found in products from license- owning brands such as Arcteryx, Patagonia, The North Face etc, and seen being used in jackets, shoes, tents, and a variety of other enduring goods. It can also be seen being used in fire and safety equipment, space exploration and law enforcement. The textile Gore-Tex is known as a finish laminate. This means it contains a face textile on a backer technology as well as a membrane, all of which are sealed together. Depending on the desired outcome properties a company wishes to produce, it can be found in three primary constructions. These would be a two layer (2L) version, two and a half layer (2.5L) version, and three layer (3L) version. The additional layers increase durability and decrease weight. The most common and most affordable of these varieties would be those with two layers. In order to give these textiles such rugged, reliable and durable qualities they must be made synthetically with a regimented process and sourced from virgin materials. Then of course, there are additional inputs that must be applied to get this product to its customer, through its life and eventually to the landfill. Overall, the raw materials that go into sourcing, manufacturing, distributing, using and disposing of Gore Tex majorilly come from crude single use sources, particularly petroleum which gives Gore-Tex and the materials that go into it a very linear life cycle.
Raw Materials and Manufacturing
So, what goes into making Gore-Tex ready to use? As mentioned, the most commonly encountered form of Gore-Tex is made of two materials that are layered together, and is the style that will be focused on from here on out. These layers include polytetrafluorethylene, a high performance fluoropolymer (known as PTFE) (this is the layer of material which gives Gore-tex its desirable waterproof qualities), and a layer of nylon which makes it more comfortable for the wearer. While it may sound unfamiliar, PTFE also goes by the more commonly known, trademarked name, teflon. This can be found in everyday household items from non-stick pots and pans, to dental floss and microwave popcorn bags. This material consists of fluorine molecules bound to carbon, which creates a very strong bond. This incredibly strong bond makes PTFE a microporous finish. “Each square inch of the GORE‑TEX membrane has nine billion pores. Each of these tiny holes is 20,000 times smaller than a water droplet.”(Team Gore 3 December 2019 et al.) This means water simply cannot penetrate the materials surface. Water vapor molecules (sweat) on the other hand, are 700 times smaller than these pores, which makes it breathable, yet waterproof. This waterproof breathability is what set Gore-Tex apart from competing textiles in the industry.
To create this desirable bond, chloroform, hydrofluoric acid, and fluorspar must be combined through a process known as pyrolysis. This creates TFE. At room temperature, TFE is a gas, which must then be polymerized into the pellet or powder form of PTFE (Martucci).This second process uses initiators such as ammonium persulfate or disuccinic acid as well as the key ingredient of water. This is then formed into a solid with the input of heat (Sewport). A layer of nylon is then applied to this stretched solid form of PTFE. Nylon is another strong synthetic polymer. It is a chain that forms at the interface of a hexanedioic acid and 1,6-diaminohexane, which can be woven. To make these two monomers, cyclohexane and adiponitrile are used- both of which are derived from crude oil (Wells). These layers of nylon and PTFE are then bonded together. Currently, the Gore company is exploring options to increase the sustainability of their textiles in the near future. They are working to incorporate recycled nylon into their products. This recycled nylon alternative is sourced from post industrial waste, particularly from excess fishing products and carpets (Ross MacLaine Gore Fabrics Division Sustainability Leader). Unfortunately, these recycled materials are not yet being used in the product.
There is one last step Gore-tex must take before it is prepared to depart to its manufacturing partners. This is the addition of a “DWR” or Durable Water Repellent which will be laminated to the membrane of the textile. These coatings that are applied cause water to bead and roll off of the surface of the Gore-tex rather than puddle on the surface. While the textile is still fully waterproof without this addition, it could become clammy as water accumulates on the surface making the product far less comfortable for the user. There is no reliable information available regarding the specific durable water repellent utilized by Gore-tex, although there are key features shared among the varieties of DWR used by the leading outdoor apparel brands. Typically, coatings that are applied contain side-chain fluorinated polymers (SFP’s) because of their desired oil and water repellent properties. The polymers that are typically present are polyurethanes or acrylates, and alongside these, polyfluoroalkyl substances can be found (Holmquist et al.) Through various natural methods of degradation, these polyfluoroalkyl substances can be transformed into perfluoroalkyl acids (PFAS). According to the Agency for Toxic Substances and Disease Registry, continued exposure to these PFAS has been linked to fertility issues, changes to the immune system, liver damage, and a variety of other health issues (US Department of Veterans Affairs). Unfortunately, the end of Gore-tex’s initial manufacturing phase is not the only time where this harmful durable water repellent coating arises. Since this coating degrades, it must be reapplied by the end consumer in order to assure comfort and product longevity.
Transportation
Before this Gore product is ready to be used, the textile must make it from the manufacturing center to its end customer. Since Gore is simply a supplier and manufacturer of the textile, they do not assemble the final product that their textile will be incorporated in. It must be transported to alternate manufacturing facilities vfor assembly by companies such as Patagonia, The North Face, and Arc’teryx. While there are many end uses for the textile, for the sake of this life cycle analysis we will focus on its main utilization in the North American market— the production of lightweight waterproof outer garments. While Gore-tex has factories around the world, including countries such as Scotland and Germany, Japan , China, and the United States, the final product that is ready to be purchased by consumers is typically assembled in Indonesia. So, after the textile is transported to another country, like Indonesia, for assembly, it must be transported once again to a retailer that can provide the interface for purchasing the Gore-tex product by the end user. This second leg of transportation is estimated to take place overland or via ship transport 90 percent of the time, and via air transport 10 percent of the time. The estimated round trip car journey for the customer to purchase the jacket at this retailer is estimated to be 10 kilometers. All of these methods of transportation require the input of fossil fuels such as oil or coal which must be mined from the earth. Additionally, in order to ship these products they must be packaged for protection and organization. While the material these products are shipped in will vary based on the company possessing the Gore-tex license, it is likely that polybags will be used to protect the products during the transportation process. These bags are typically made using polyethylene which is created using components which, like the fuel used in transportation, are obtained from natural gas and petroleum (Kinhal).
Use and Maintenance
After this transportation, the product has arrived with its user and must be cared for appropriately to maximize its quality and lifespan. The suggested mechanisms that should be used to care for Gore-tex products include bi-annual washing and drying, done separately from other garments in a standard at home washer and dryer, as well as the reapplication of water repellent coatings. The washing requires the input of warm water as well as a small amount of liquid detergent and energy. The suggested at-home reapplication of Durable Water Repellent uses the same toxic and non-biodegradable chemicals as the process that takes place just before the Gore-tex is distributed to its licensed partners. With consumers following these care procedures Gore-tex apparel is estimated to last approximately five years.
Recycling
Once the user is ready to dispose of their apparel, there are very limited options in place. Since the textile is made of a multitude of varying polymers that are bound together, they are essentially impossible to recycle. While the PTFE in Gore-tex’s membrane is technically recyclable, the way it's bound to its surrounding materials makes its removal and recycling process not worth the energy that would need to be imputed (Lakshmanan). Additionally, since Gore-tex is made to endure extreme conditions for its user, this means it’s unfortunately able to endure the conditions of a landfill, and will not degrade over time. For this reason, Gore-tex and similarly non degradable materials are left with the only option of being incinerated in a combustion chamber. The process of incineration requires incredibly high temperatures, ranging between 1,600 and 2,500 degrees fahrenheit. In order to produce a chamber this hot, fossil fuels must once again be burnt.
Conclusion
When we take a step back and look at the overall trends of raw material inputs throughout the lifespan of Gore-tex textiles, petroleum is a major component of nearly every step. Both layers of the “2L” version of Gore-tex, PTFE and nylon, are produced with petroleum. From there, the textile is transported to the location where it will be further assembled into its form as a consumer product. This process of transportation also requires the input of fossil fuels. Finally, once the product has been used by its purchaser, its highly synthesized properties are unable to be naturally degraded and must require large energy inputs to reach a temperature where it can ultimately be incinerated. So, while these properties that Gore-tex possesses are so coveted for defying nature and keeping its user comfortable in extreme conditions, the raw material inputs that are gathered to synthesize the textile are unable to be used more than once, giving Gore-tex a linear life cycle that begins with being pumped from the ground, and quickly ends with being put in its grave.
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Georgia Heitz
DES 040A
March 15, 2023
Gore-Tex Energy Paper
Introduction
Gore-Tex fabric is popular due to its durability and versatility. It’s been adapted to many different industries including: space exploration, medical science, and outdoor fashion. Gore-Tex dominates the outdoor clothing space. Its waterproof and breathable characteristics make it like no other competing material on the market. Here’s the major downside: the raw materials used to make Gore-Tex are petroleum-based. Its manufacturing is energy intensive. Its shipped globally to hundreds of clothing manufacturers, then shipped to customers or picked up at retail stores. From the beginning stages of sourcing materials to the end of its life-cycle, Gore-Tex consumes massive amounts of energy.
Raw Materials
The original Gore-Tex fabric was developed by W.L. Gore and Associates in 1969 (“Robert”). With only some minor tweaks over the years, the technology and processes used to create Gore-Tex have remained the same. The fabric is made up of two main components: Polytetrafluoroethylene (PTFE) and nylon (“What is Polytetrafluoroethylene”). Both are essential to Gore-Tex’s success. They help the fabric be waterproof, breathable, and tear-resistant. In order to make PTFE and nylon, the company must source all the primary raw materials. This is the first big energy user.
PTFE is composed of several main materials. The first is fluorspar. Fluorspar is made of the primary raw material fluorite. Fluorite is mined using fossil and electric mechanical energy to extract it from the earth. This uses oil and emits carbon pollution as well as nitrogen-oxides and sulfur oxides, which contribute to smog and asthma. Human energy is then used to sort, wash, and separate the fluorite (Burchard).
Next is hydrofluoric acid. Hydrofluoric acid is composed of the fluoride and sulfuric acid. Fluoride is made of Fluorite. Sulfuric acid is a secondary raw material made industrially from the reaction of water with sulfur trioxide (“Sulfuric”). Sulfur trioxide comes from a reaction of sulfur dioxide with oxygen and in the presence of a platinum catalyst (Clark). This process takes in thermal energy, usually from fossil gas or electricity, in order to act as a catalyst for chemical change that forms the new product. Human energy is needed to oversee all this in the industrial factory. The last material needed to make PTFE is chloroform. Chloroform is the product of a reaction between chlorine gas and methane gas. Methane gas is the main ingredient in fossil natural gas, and comes from oil and gas wells. Chlorine is formed when sodium or potassium chloride is electrolyzed. An electric current converts the ions (“Chlorine”). This process takes both human and electrical energy to set up and control the technology. Chemical energy is used to convert the sodium ions.
Nylon is the second essential component in Gore-Tex fabric. Crude oil is the primary raw material for Nylon and is extracted from the earth using the traditional method of drills and pumps. These drills and pumps use a diesel generator to create electricity or electrical power from the grid (“Oil”). From there, hexamethylenediamine, also known as diamine acid, is extracted from the oil using chemical energy reactions, which require further heating with fossil energy, usually in the form of natural gas (“What is Nylon”). Adipic acid is the second component needed to make nylon. It’s formed by mixing cyclohexanone and cyclohexanol (“Adipic”). Cyclohexanone and cyclohexanol are made in a controlled lab environment by professional chemical companies. They expose the molecules to air and use a cobalt catalyst. This causes oxidation and the forming of adipic acid.
The first step of the life cycle is done. The primary raw materials have been created and now are transported by truck or train, using fossil fuels. The next step is manufacturing the final fabric. During this phase the primary raw materials will be combined through chemical processes to form a laminated PTFE and nylon.
Manufacturing
Polytetrafluorethylene (PTFE) is made up of Tetrafluoroethylene (TFE). TFE can be manufactured in two ways: suspension polymerization or dispersion polymerization. These methods combine the raw ingredients discussed above: fluorspar, hydrofluoric acid, and chloroform (“What is Polytetrafluoroethylene”). Both suspension and dispersion polymerization require lots of energy provided by fossil derived electricity.
Human energy is used to set up and control the technology. Mechanical energy is used to move, fill, and seal a chamber. Thermal energy is used to heat the ingredients. The latter two are derived from fossil gas for heat or electricity, which comes from fossil fuels. The heat then acts as a catalyst for the chemical energy. This causes a reaction that creates the TFE. Mechanical energy is used to stretch the PTFE while it's heated. The result is ePTFE (“What is Polytetrafluoroethylene”).
To make nylon, a reaction is set up between adipic acid and diamine acid. The result is nylon salt. The salt is purified, polymerized, stretched, and chipped. The nylon takes the form of pellets and is melted and spun (“What is Nylon”). This process takes human energy to run the experiment and chemical energy to create a physical change. Heat from fossil gas is used to melt the nylon pellets so they will stretch. Mechanical energy is used to stretch and cool the nylon fiber. The next step is to combine ePTFE and nylon to make the final Gore-Tex fabric.
Nylon and ePTFE are bonded together. This results in a Gore-Tex laminate. The exact bonding process is proprietary, however thermal energy would be essential to bind the nylon to the ePTFE. The electricity to power this is coming from the burning of fossil fuels. The Gore-Tex is then finished with a durable water repellency (DWR). While this step is not essential, it helps the fabric last longer. The DWR is made from a polymer which is also based on petroleum-sourced materials. The finished Gore-Tex laminate is then used to create a variety of waterproof and breathable outdoor apparel (“What is Gore-Tex”). Once the Gore-Tex is manufactured, partner brands like: Patagonia, Marmot, and Nike then buy and use the fabric to make their designs (“Our Brand”).
Transportation & Distribution
It’s time for the Gore-Tex laminate to be transported and distributed to its partner brands. Gore-Tex is an “ingredient brand” (“Our Brand”). This means they work directly with their buyer to make Gore-Tex certified products. W.L. Gore and Associates have manufacturing plants in the U.S., Germany, the United Kingdom, Japan, and China. From there, the fabric is shipped to its partner brands (“Gore”). Once the Gore-Tex fabric has made it into the hands of the brand partners, they’ll sew a huge variety of garments, tents, and other outdoor products. There's no public data on the total tons of Gore-Tex shipped or the exact location it’s shipped to. It’s known that the product is shipped using trucks or ships. For trucks, every 100 tons of Gore-Tex fabric, which is about five big truckloads, uses 71 gallons of gasoline to move 100 miles (Arcy). Since Gore-Tex manufacturing plants are dispersed widely, when shipping trucks are used they will have to travel a long distance. This means copious amounts of diesel fuel will be used.
For shipping by container ship, if you shipped 50 twenty-foot-size containers from Europe to the U.S., that would use the equivalent of 3375 gallons of gasoline. If you shipped from China, the amount would be about double (“Fuel”). Now, the finished product arrives at the brand store or a distribution company like Amazon. The customer then has to drive to the store to pick up the product or a delivery truck drives it to their house. For this entire process, human energy is used to drive the boat or vehicle. Fossil fuel, in the form of oil and gasoline power the boats or trucks. According to a Life Cycle Assessment of a Gore-Tex jacket, the production and distribution stages make up about “two thirds of the product’s Global Warming Potential (GWP) (“Life Cycle identifies”). This relates to the energy impact of a Gore-Tex jacket, confirming how much energy is consumed throughout the lifecycle.
Now, the energy intensive stages of the lifecycle are over. After Gore-Tex makes it into stores, it’s sold to consumers. From there, it’s the consumer's responsibility to maintain the product.
Maintenance & Use
Gore-Tex fabric takes minimal energy to use and maintain. It takes only a small amount of human energy to put on and wear the Gore-Tex garment. However, maintenance is essential to the longevity of the apparel. It’s recommended to wash and dry when necessary. The DWR can be restored by tumbling the garment (“Care”). This can be done a number of times throughout the life cycle. For example, if you wash a Gore-Tex jacket six times per year over a five-year lifetime, that’s 30 total washes. If it takes 46 kilowatt hours of energy per wash, then after five years the maintenance would take around 1400 kWh (“How many”). This equals about two months of electricity consumption for the average California household (“Cost”). Depending on the household, the primary energy source for electricity would most likely be fossil fuels or solar power. Mechanical energy is used to run the washing machine and human energy is to start the process.
How a consumer treats their Gore-Tex apparel has a big impact on the products GWP (Global Warming Potential). According to an article on the Life Cycle Assessment of a standard Gore-Tex jacket, consumer care accounts for 35% of total GWP. The longer a customer can make their Gore-Tex apparel last, the smaller the ecological footprint (“Life Cycle GORE ”).
Recycling & Waste
Gore-Tex fabric is very difficult to recycle. Gore-Tex tried to implement a recycling program, but it was shut down in the late 1990s (Noss). PTFE alone can sometimes be recyclable, but once it’s laminated to another fabric it becomes too difficult to separate (Lakshmanan). Today, recycling technology can only recycle one material at a time (“Is Gore-Tex Environmentally”).
PTFE doesn’t degrade, so there’s no risk of chemicals being leaked into the air or water (“How should”). This is important in case Gore-Tex apparel ends up in the landfill, it won’t be toxic to the environment. If Gore-Tex apparel ends up in the landfill it requires fossil gas for garbage trucks to haul it to the dump and for bulldozers to bury it. However, most Gore-Tex is taken to an incinerator with other waterproof apparel. There it’s put in an oxygenated combustion chamber. This chamber gets heated to extreme temperatures. The garments are burned and turned into ash and gasses (Alexander). Incineration is carbon-intensive. It uses lots of fossil fuel to power the electricity needed. The electricity triggers the machinery to burn the items. The gasses that are released during incineration are cooled using water. As a result steam is created from the heat. That steam is then used to power electrical generators (Alexander). While some thermal energy can be captured and redirected, most of the energy for the electricity is still coming from fossil fuels.
Conclusions
Gore-Tex fabric is made through multiple energy-intensive processes. Fossil oil is a primary source material and fossil fuels are the primary energy source used to create electricity or drive machinery. Transportation and distribution to manufacturers, shipping to retail outlets, plus final shipping to customers all demand lots of energy in the form of oil and fossil fuels. Using unsustainable energy sources in such large amounts wreaks havoc on the environment and climate. GORE published a study that showed “that during its entire lifetime a GORE-TEX jacket emits a total of 72.7 kg of CO2-eq., consumes 2.08 m3 of fresh water and 992 MJ of primary energy, the equivalent of 29 liters of petrol (“Life Cycle identifies”).” This is around 7.6 gallons of oil per jacket.
Gore-Tex fabric is favored in the outdoor apparel space due its unique characteristics. However, as this paper demonstrates, it’s extremely energy intensive to make. Environmentally conscious consumers may want to choose a different fabric.
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Oriana Gonzalez
DES 40A
3/14/2023
Gore-Tex Waste Paper
The first waterproof jackets weren’t breathable, which resulted in sweat getting trapped inside, similar to wearing a plastic bag. Could you imagine how that feels? With the discovery of Gore-Tex membranes, this was no longer an issue. However, this brought a new problem, Gore-Tex membranes have several forever chemicals that are not only harmful to the environment but also to human beings. In my opinion, it is important to ask ourselves, is it really worth having a 100% waterproof membrane? Studies have shown that making the membrane less resistant to water will substantially lower the negative impacts of Gore-Tex.
This paper focuses on the manufacturing process of Gore-Tex and how its waterproof properties are harmful to the environment. Gore-Tex has several types of membrane, however in this paper we will focus on the two layer membrane. The membrane consists of two layers one made of nylon, which is in contact with the skin and the second one made out of Expanded PTFE (Polytetrafluoroethylene). After the research of the topic, it is clear that Gore-Tex could make alternative fabrics that aren’t 100% waterproof but they aren’t as harmful to the environment. First, we analyze the different primary raw materials used to create Gore-Tex as well as their main waste, emissions and byproducts and then turn to more general concerns associated with the manufacturing process of secondary raw materials. Lastly, we discuss Gore-Tex use, recycling, and waste management. Regardless of the environmentally damaging waste, Gore-Tex continues to rely on the extraction of fossil fuels and other toxic chemicals.
Extraction of minerals generates a great part of the emissions of the manufacturing process. Tetrafluoroethylene (TFE) is the first in the line of production for EPTFE. TFE is fluorocarbon formulated with fluorite, chloroform and hydrofluoric acid. The first raw material in the life cycle is fluorite also known by its commercial name fluorspar. The acquisition of this mineral is usually from mines in different crystal forms. For that reason, it can present impurities such as silicon, aluminum and magnesium. A study by the British Geological Survey estimated that fluorite reserves in the United States are almost exhausted. Most of the reserves are found in Mexico, Vietnam, South Africa, and China. This same report shows that all the fluorite’s waste comes from the mining process from crushing the ore such as Limestone producing silica tailings, mine slimes, and from floatation and filtration producing tailings. Fluorite is used in the manufacturing process to the formulation of hydrofluoric acid (HF) used for acid-grade fluorspar. A report from the 50s called Screening Study on Feasibility of Standards of Performance for Hydrofluoric Acid Manufacture by Boscas shows that HF emissions were very common on fluorspan plants. Most of the emissions depended on how effective the tail gas scrubbers were, however, fugitive emissions were still high. Nowadays the production of fluorite still produces potent greenhouse gasses known as Hydrofluorocarbons (HFCs). Both fluorite and hydrofluoric acid are used to make TFE.
As mentioned before, a great part of the extraction of this mineral occurs in China. A report by Yin, H. et al. says, “With higher tropopause height in summer and autumn, more stratospheric HF transport downward to the troposphere and then are removed through wet deposit along with rainfall or destroyed by photolysis, resulting in lower stratospheric HF concentration in these seasons, and vice versa for higher stratospheric HF concentration in late winter and spring” (5). In other words, the emission of HF in North China depends on the session. Another organic compound or raw material used in the formulation of TFE is chloroform which is a byproduct of chlorination. A report by the U.S. The Environmental Protection Agency says, “Potential sources of chloroform emissions include process vents; chloroform storage tanks; and fugitive emission sources such as process valves, pumps, compressors, and pressure relief valves” (10). I would like to bring to your attention that in most of the cases, the emissions of a plant will vary from one to the other, depending on their methods and management of the machines and minerals. Another report from North China observes “Anthropogenic chlorine emissions, including those from biomass burning, coal combustion and biofuel burning, are the main sources of Cl−, which could potentially affect the formation of secondary pollutants in the troposphere” (Zhang, Y. et al. 22). Put it differently, chlorine emissions are also detrimental to the atmosphere. Furthermore, there are other waste and byproducts generated in the Gore-Tex life cycle.
Most of the waste that comes from Gore-Tex’s manufacturing, processing and formulation are toxic. TFE method of preparation is pyrolysis. During this process, byproducts of compounds found on the Hazardous Substance List are produced. A paper called Introduction to Fluoropolymers' by Sina Ebnesajjad mentions a list of TFE’s bypoducts, “hexafluoropropylene, perfluorocyclobutane and octafluoroisobutylene, 1-chloro-1,1,2,2-tetrafluoroethane, 2-chloro-1,1,1,2,3,3-Hexafluoropropane, and a small amount of highly toxic perfluoroisobutylene” (91). However, some of these byproducts can be used such as hexafluoropropylene, perfluorocyclobutane and octafluoroisobutylene. They are reused in the production of copolymers, food packaging gas and a food propellant, and creation of other plastics and rubber. These substances are required to have safety precautions and ventilated areas because they are highly harmful to human contact. For example, a hazardous substance fact sheet by the New Jersey Department of Health and Senior Services shows that high exposure to Hexafluoropropylene can cause headaches, severe poisoning and even death. In short, if handled correctly these substances can be widely used in the food packaging industry and other areas. Emissions from ETF plants are also reported. A study by the National Center for Biotechnology Information says, “Chlorodifluoromethane was reported as the single largest contributor to the U.S. halocarbon global warming potential. The country with the second highest emission of chlorodifluoromethane was the Russian Federation at 20,500 tons”. In other words, TFE generates very powerful greenhouse gasses that highly contributes to the depletion of the ozone layer. Another important manufacturing process is for the formation of nylon. In Kate Fletcher’s book Sustainable Fashion and Textiles: Design Journeys, she mentions that Nylon creates emissions of nitrous oxide (N2O). It is said that this emission is 300 times more damaging than CO24 not only because it can last up to 120 years but also it interfire in the filtration of UV radiation when it reaches the upper atmosphere and deplete the layer of stratospheric ozone. Other harmful emissions are generated in the next manufacturing process.
Other waste and byproducts are generated in the formulation next step which is PTFE. During this process one of the most alarming toxic emissions is generated. PFAS (per- and polyfluoroalkyl substances) and PFOS (perfluoro-octane sulfonic acid) or C8 are found in the manufacturing process of Gore-Tex. Due to the high persistence in the environment, these byproducts are found in the blood of human beings, animals. They are also found in soil, fish, and water all around the world. One study made by Scientists from Toxic-Free Future, Indiana University, the University of Washington, and Seattle Children’s Research Institute discovered that, “PFAS (per- and polyfluorinated substances)—including new generation compounds currently in use—build up in people” (6). This research shows these substances, also called forever chemicals, were found in breast milk from mothers. This report also finds other waste that is used “The pyrolysis of waste PTFE results in the formation of light ends (CF4 and C2F6), TFE, HFP, OFCB and heavy ends (1-OFB and 2-OFB).” These substances can also be dangerous if handled incorrectly. Waste is used in the medical field such as narcotics, and it can also be used in electrodomestics as refrigerants.
Lastly, the last component of Gore-Tex is Expanded PTFE (polytetrafluoroethylene). EPTFE is generated from 100% virgin PTFE and “expanded” means the state of the material. In this process, their is also a possibility to generate byproducts mention above such as hexafluoropropylene (HFP), octafluorocyclobutane (OFCB) and 1-, 2- and iso-octafluorobutylenes. In the factory, Gore-Tex makes cuts in the fabric to maximize it and minimize waste. For that reason, once EPTFE is in its fabric state the only waste generated are cuttings and chips. A report from Toxic-Free Future, announced that Gore-Tex was working on launching at the end of 2022 a new membrane that was PFAS-free. Usually the PFAS are found in the coating of the fabric that makes it waterproof. However, I checked the website and I didn’t see this new membrane.
Gore-Tex is aware of their footprint and they are taking action to offset it. The company is dedicated to making their products last longer in the “use” part of the life cycle. In the Life Cycle Assessment of a GORE branded waterproof, windproof and breathable jacket they stipulate that a jacket can last 5-8 years depending on its usage and consume care. In other words, with every year that Gore-Tex products are used, the smaller their environmental impact. For that reason, Gore-Tex is known for testing their products by putting them in extreme conditions such as a machine for running shoes and a wind and water machine for jackets. Most of the brands that are partnered with Gore-Tex such as Patagonia trusts Gore-Tex extreme testing to make their products last longer. Partnered brands also have a second hand trade option in their website, so people that get tired of their products can exchange them for different ones, helping to reduce the footprint per year. However, these companies still don’t have a way to recycle their products. One should argue that this could be one of the solutions, however, their products are affected by the fashion industry trends. Making some of the products not desirable even when there's ways to exchange them. Another important factor that is mentioned in the Life Cycle Assessment of Gore-Tex says, “The jacket’s production and distribution have an important impact: 65% of Global Warming Potential (GWP)” (6). In other words, transportation is a big part of emissions of the manufacturing process of Gore-Tex. Reported CO2 emissions from trucks, chips, rails, etc. during the distribution, allocation, and retailing process. Most of the raw materials come from East Asia and northern Europe to their main three plants located in the U.S and Germany.
There is not much information about the recycle and waste management of Gore-Tex. In the recycling process of the life cycle of Gore-Tex, the U.S. The Geological Survey observed that some waste from HF and fluorides can be recycled in the aluminum industry. Researchers are still investigating other ways to recycle EPTFE, however there are not many advances in that area. A report from Waste Today was from researchers in Australia say, “have reportedly used 3D printing technology to develop a flow reactor that is able to transform a hazardous Teflon manufacturing byproduct into a “synthetic building block” that can be used by the polymers industry. It is hard to know what the emissions of pollutants are from this stage. Gore-Tex products are non-biodegradable. There are studies that have tried forms to find ways to break it down with heat, however, as we discuss above the pyrolysis process is the most harmful stage of both PTFE and EPTFE. Other studies have shown that in this process three types of PTFE powders or microplastics that might be cancerogenous or harmful to the environment and human beings.
In conclusion, Gore-Tex products have shown that the extraction of raw materials contributes to the waste of Gore-Tex, however, its major environmental footprint comes from the manufacturing process. In this paper we analyze primary raw materials used to create Gore-Tex as well as their main waste, emissions and byproducts and then turn to more general concerns associated with the manufacturing process of secondary raw materials. In my opinion, when buying one of the Gore-Tex products one should ask themselves, do I really need this product? If so, is it something I see myself wearing for 5 to 8 years?
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