Design Life-Cycle

Image citations

“Download Cutout Cannabis Leaf Simplicity Watercolor Painting. for Free.” Vecteezy, 5 Aug. 2022, https://www.vecteezy.com/png/9974124-cutout-cannabis-leaf-simplicity-watercolor-painting. 

“Hemp Texture Linen.” Fabricut, https://fabricut.com/fabric/5401001/hemp-texture/linen. 

“Square, Rectangular Long Pieces of Canvas, Cut Burlap Fabric, Patch for Clothes, Dry Garbage, Scraps of Fabric, Background for Text from Fabric Isolated on a White Background. Stock Photo.” Adobe Stock, https://stock.adobe.com/images/square-rectangular-long-pieces-of-canvas-cut-burlap-fabric-patch-for-clothes-dry-garbage-scraps-of-fabric-background-for-text-from-fabric-isolated-on-a-white-background/377677491. 

“Zipper.” PurePNG, 16 May 2018, https://purepng.com/photo/9556/clothing-zipper. 

 Materials paper:

Lucien de la Jara-Smith

Katelyn Cho, Cassie Ngo

Des 40A

Professor Cogdell

Hemp Cotton Blend Backpack: Materials

Hemp backpacks have a reputation to be eco-friendly for the materials used and process to create them. By using hemp and organic cotton blended fabric, the hemp backpack is the recipe to go eco-friendly and help the environment compared to other backpack materials. Hemp is an eco-friendly material but it is mixed with cotton that is known for harming the environment. Both properties together make a stronger and more long-lasting material. The cotton and hemp goes through a long process of blending to create the fabric and process to dye. Then, its cut and sewn to create the backpack itself. Cardboard is made to be shipped and transported to the consumer. Hemp backpacks are made for their durability, performance, and environmental friendliness.

The two raw materials to create the blended textile are hemp and organic cotton. At first, we believed hemp to have been grown from the same plant that marijuana is grown, but there is a difference. Hemp and marijuana come from the same species called cannabinoid sativa. The difference between them is that hemp has a low THC that cannot trigger a “high” like you would consuming marijuana. Hemp is grown specifically for making textiles and garments. It is an annual crop that can adapt and grow easily, but the only factor that makes hemp grow irregularly is wet soil. Because hemp has a natural repellent of insects and weed suppressor, it is usually grown organically to have the best results in strength and fineness. On the other hand, hemp can also be grown with nitrogen fertilizer. After it is grown and harvested, hemp fibers are extracted in a process called retting. It can be either water retting or chemical retting. Water retting is usually done with warm water to speed up the process and with the outcome of high-quality fibers. Chemical retting is the process of fibers being submerged in a mixture of water, sulfuric acid, sodium or potassium hydroxide, soda ash, and chlorinated lime. 

Although hemp is quite eco-friendly, cotton has some downsides. Cotton can be adaptable to its environment and can be grown in several places but requires lots of water and materials to be able to grow. Cotton production uses one to six percent of global fresh water. Because of its very water intensive consumption, cotton needs rich soil that can hold an abundance of water. Cotton's nutrient uptake efficiency is low so it needs to be supplemented with fertilizers and management of soil. A synthetic fertilizer is usually made with nitrogen, potassium, and phosphorus. To protect cottons from being invaded by bugs or insects it needs to be administered with pesticides and herbicides. Pesticides can vary but most chemical groups used to make them are pyrethroid and organophosphorus. Herbicides also vary but have different chemical groups like substituted trianize, substituted urea, dinitroaniline, and organoarsenic. After the cotton is grown, the cotton is hand picked and the raw cotton seed is harvested.

Another main component to the backpack is the zipper. The three common raw materials to create a zipper are aluminum, stainless steel, and brass. Stainless steel is mainly excavated in china and distributed after it being processed. The stainless steel is the main material alongside iron, chromium, and carbon which have properties that do not rustand oxodize as easily. Then the zipper is coated in brass to protect the product from even more rust and corrosion.

Now that the materials are grown, the hemp and cotton need to go through a process to convert into a blended fabric. To create the blended fabric, it goes through lots of steps before the spinning process.  First the hemp and cotton fibers are emulsified to start the process. The fibers are submerged into a water and wax solution to increase the mass of the fibers then conditioned for twenty four to forty eight hours. After, the blend  it is transferred to be carded. Finally, after all the prepping for the blend, it is brought to a roto-spinning frame to be spun. To finish the fabric, it is sheared and washed. The fibers are now spun to create yarn. The yarn now has to be turned into fabric so the yarn is brought to a knitting machine to create the final product, the fabric.

To create fun colorful patterns on the cotton blended fabric, there is a way to dye fabrics in a natural way without using synthetic dyes. Colors can be extracted from many natural sources such as plants, insects, animals, minerals, microbes, fungi, and algae. The materials can differ for what color you would like. For example, you could use the leaves of a woad plant to create blue dye, or lac extract from the resin of the insects discharge to create red dye. Many of these materials go through different processes to become usable to dye the fabric. Before it is dyed, the fabric is washed again to remove pollutants that could be on the fabric with a washing agent and rinsed with distilled water after that for several times. Then it goes through a process of applying mordanting agent, tannin powder, or potassium alum crystal to ensure the dye would stick to the fabric. The application of these materials can vary for different outcomes. After finishing the prepping of the fabric, the dye is then boiled with water to have the fabric take the dye. Usually, the fabric should be in the bath for an hour while being turned regularly. After the hour mark, the bath needs to cool slowly whilst the fabric is still in the bath. Its recommended for yellow dye to even stay overnight in the bath to have a better result. After removing the fabric from the bath, rinse the fabric under cool water and let it dry. 

The manufacturing process of a zipper is limited, but there is general information. The zipper teeth can be twisted into shape or be created with molds. Most likely the zipper itself is created with a mold as well. Most of these processes need heat to be able to mold or change the metal so crude oil, coal, or electricity to create the energy needed. 

The fabric and zipper are done, but the backpack needs to be made. Most of the time, the process is done with human labor. The fabric is cut and sewn together with the zipper with cotton thread.

Information for transferring hemp bag materials is little to none, but with general company processes, I was able to find information of raw materials used in the process.An item like hemp backpacks are generallyare packaged into cardboard boxes for shipment. The raw material for cardboard boxes are pine trees. Pine trees are grown and cut down to be brought to a pulp mill where they go through a chemical sulfate process to make the pulp. The pulp is converted to paper that is converted into cardboard with cornstarch and water. Now that the hemp backpack is ready to ship, the planes or trucks shipping them to customers use fossil fuels to run the vehicles. Fossil fuels are located at the earth's crust, which is where it is extracted and used to fuel vehicles to ship and transport many products like the hemp bag.

To maintain a hemp bag, washing the bag could be helpful. To wash them, typically they can be washed in a washing machine with detergent. A common washing machine will use forty to forty five gallons of water if theres a full load, while a high efficiency wahing machine will use fifteen to thirty gallons of water.

Through my research, I did not find information of raw materials that could be in the process of recycling nor waste. There is some research in decomposing blended fabrics with chemicals but its not fully understood yet.

Although the hemp bag uses cotton and contradicts its eco friendliness, I believe theres more positives presented than negatives. According to Hemp as a potential raw material toward a sustainable world: A review, “Cotton is generally blended with hemp to reduce its spinning difficulties arising from pectin and lignin of hemp fiber [136]. Fabric from this blended yarn shows better performance in moisture absorption, air permeability, anti-mold and antibacterial property, UV protection and antistatic properties [137].” To reduce the impact of cotton, it is blended with hemp, whilst bringing benefit to the hemp did not have. Through the hemp backpacks life cycle, there was several different ways to grow, apply, or create the materials. The outcome can vary to eco-friendlyness, higher quality or product, or to have different results. The hemp cotton blended backpack has reasons to be used and made for its durability, performance and eco friendliness.

Bibliography

Review.” Heliyon, U.S. National Library of Medicine, 13 Jan. 2022, www.ncbi.nlm.nih.gov/pmc/articles/PMC8819531/.

Brown, Tyson, and National Geographic Society. “Fossil Fuels.” Education, National Geographic, 19 May 2022, https://education.nationalgeographic.org/resource/fossil-fuels/. 

Chang, Claudia. “Zippers - Design Life.” Design Life Cycle, Mar. 2014, www.designlife-cycle.com/zippers.

“Corrugated Cardboard.” How Products Are Made, http://www.madehow.com/Volume-1/Corrugated-Cardboard.html. 

G. Baydar a, et al. “Life Cycle Assessment of Cotton Textile Products in Turkey.” Resources, Conservation and Recycling, Elsevier, 17 Oct. 2015, www.sciencedirect.com/science/article/pii/S0921344915300677.

“Guide to Natural Dyes.” Natural Dyes, https://naturaldyes.ca/instructions. 

Kozlowski, R., et al. Processing of Hemp Fiber in Blends in Blends with Cotton for Apparel Fabrics , Institute of Natural Fibers, Poznan POLAND, 2003, https://www.icac.org/Content/EventDocuments/PdfFilesced6a9b1_0a1f_41bb_b709_52b35a851cf0/Processing%20of%20hemp%20fiber%20in%20blends%20with%20cotton%20for%20apparel%20fabrics.pdf. 

Leggett, Rochelle. “How Many Gallons of Water Does the Average Washing Machine Hold When Full?” Home Guides | SF Gate, 17 Nov. 2020, https://homeguides.sfgate.com/many-gallons-water-average-washing-machine-hold-full-80612.html. 

Malone, Trey. “CBD, Marijuana and Hemp: What Is the Difference among These Cannabis Products, and Which Are Legal?” MSUToday, 6 Apr. 2021, https://msutoday.msu.edu/news/2021/cbd-marijuana-and-hemp. 

Meenakshi Ahirwar & B. K. Behera (2022) Development of hemp-blended cotton fabrics and analysis on handle behavior, low-stress mechanical and aesthetic properties, The Journal of The Textile Institute, 113:5, 934-942, DOI: 10.1080/00405000.2021.1909799 

Mijas, Gabriela et al. “Study of Dyeing Process of Hemp/Cotton Fabrics by Using Natural Dyes Obtained from Rubia tinctorum L. and Calendula officialis.” Polymers 14 (2022): n. Pag.

Ramesh, Manickam. “Hemp, Jute, Banana, Kenaf, Ramie, Sisal Fibers.” Handbook of Properties of Textile and Technical Fibres (Second Edition), Woodhead Publishing, 29 Jan. 2018, https://www.sciencedirect.com/science/article/pii/B9780081012727000092. 

“Why Wear Hemp? the Benefits of Wearing Hemp Clothing.” Hemp Clothing Australia, https://www.hempclothingaustralia.com/why-wear-hemp#:~:text=Breathable%20%26%20insulating,the%20fabric%2C%20not%20against%20it. 

Zhao, Megan. “H&M Foundation-Backed Research Finds New Way to Recycle Blended Fabrics.” S&P Global Homepage, 21 Sept. 2017, https://www.spglobal.com/marketintelligence/en/news-insights/latest-news-headlines/h-m-foundation-backed-research-finds-new-way-to-recycle-blended-fabrics-41970154. 

Embodied Energy paper:

Katelyn Cho

Katelyn Cho, Cassie Ng, Lucien de la Jara-Smith

DES 40A

Professor Cogdell

Hemp Cotton Blend Backpack: Embodied Energy

As the consumer demand for product sustainability and renewability increases, companies and manufacturers have looked into more “green” replacements for commonplace items. Not excluded from this is the manufacturing of fabrics and textiles. While cotton is the world’s leading fabric being produced today, the introduction of alternative or blended fabrics such as hemp have been disrupting the conversation and proving, in some aspects, to be a suitable alternative or even competitor to the leading giant that is cotton. The embodied energy necessary to create backpacks made of a cotton hemp textile blend proves to vary in different phases of the life cycle on being more or less energy efficient and sustainable in comparison to a classic cotton backpack. 

To create a usable backpack made of a cotton hemp blended textile, there are a number of raw materials required. Both cotton and hemp must be grown for harvesting, as well as aluminum for the zipper component. As both cotton and hemp are agricultural crops, they require solar energy in the form of sunlight or an artificial recreation of sunlight, as well as water and soil to carry out the process of photosynthesis. The photosynthesis that converts the sunlight into nutrition for the plant is the main chemical energy process in the raw materials acquisition stage, which is a process that is virtually identical between hemp and cotton crops. However, cotton and hemp have very different requirements to be harvested in an effective manner. Unlike cotton, hemp “... doesn’t require pesticides, herbicides or chemical fertilisers to grow. Hemp plants are natural pest repellents that deter insects and repel mites, fungi and bacteria. Hemp is also a natural weed suppressant, naturally out-competing and shading-out the weeds in its environment.⁣” (Why Wear hemp? The Benefits of Wearing Hemp Clothing) This lessened need for pesticides and weed protection cuts much of its potential energy costs, as pesticides no longer need to be administered through mechanical or manual labor energy sources and the hemp crop can essentially be left to grow with much less careful oversight in comparison to cotton, which requires specific administration of pesticides, insecticides, and fertilizers to keep its production running smoothly(How Cotton is Made.). This greatly increases the amount of embodied energy required to grow cotton as a raw material. Additionally, hemp as an agricultural product is much more efficient to grow than cotton. A major advantage of hemp is that it “...can produce 250% more fiber than cotton… using the same amount of land” (Cholia). Resultantly, a product being created with a cotton hemp blend rather than entirely cotton requires much less energy overall for raw material acquisition due to how much simpler and streamlined the process is to grow hemp. 

As for the other components of the backpack, they would be virtually the same for either cotton or blended textile bags. According to low tech magazine, aluminum’s (a main raw material of zippers) acquisition requires “219 MJ (60,800 watt-hours)” of embodied energy per kilogram. 

Following the raw materials acquisition stage, the harvested hemp and cotton must be put through a process to eventually turn them into a blended textile, which can then be stitched together to complete the final product of a backpack. Despite hemp’s low crop maintenance in comparison to cotton, the hemp yarn/ fabric manufacturing process is much more demanding and proves to be less sustainable in terms of embodied energy. To harvest the Hemp, mechanical energy in the form of sickle bar mowers and hay swathers are used (Baxter). Hemp processing requires trimming the buds off the stalks, retting, drying, and carding (Industrial Hemp in the United States: Status and Market Potential), but this process is very time consuming and particular. Firstly, during the trimming process, the stalks must be trimmed off the bud and then cleaned and dried (Hemp Processing: Tuffman) . What makes the processing of hemp so unsustainable in comparison to cotton is the yield that hemp as a crop produces, as only 20% of the hemp fiber inside the stem is genuinely usable for textiles (Hemp Textiles in Britain). The retting process that follows is also very energy intensive, with water retting including a chemical process to “[break] the chemical bonds that hold the stem together and allows separation of the bast fibers from the woody core.” (Industrial Hemp in the United States: Status and Market Potential). This process requires not only the chemical energy that is used throughout the retting process, but specialized human labor, as “farmers and /or workers must be knowledgeable about fiber quality”(Industrial Hemp in the United States: Status and Market Potential). After retting, the hemp fibers must be dried in very specific conditions. Dryers for water retting are “ characterised by high energy consumption and the need for additional logistic solutions, which have negative environmental and economic impact[s]”(Ahmed). The high amount of energy needed specifically for drying the retted hemp fibers adds to the complexity and high energy usage of industrial hemp in comparison to the production of cotton. Following the drying process, machinery is used to sort out the fiber hurds, which can be separated with a machine called a decorticator. The long and short strands must be separated from one another, as only long strands are of any use for fabric creation, and this process can only be completed with specialized human labor . (Industrial Hemp in the United States: Status and Market Potential) Further, carding is then used to prepare the hemp strands for the “possibility to blend hemp with other cotton type fibers” when the fibers are spun into yarn (Ahmed).  

Comparatively, the processing of cotton is less intensive than hemp. The entire process uses many different types of energy sources, but mainly utilizes mechanical energy and human labor. Before any cotton can be removed by machinery, it all must be defoliated. According to madehow.com CHANGE “Defoliation (removing the leaves) is often accomplished by spraying the plant with a chemical.” The cotton harvest can then be carried out by machinery, which is much more effective than hand picking, as a “... single machine [can replace] 50 hand-pickers” (How Cotton is Made).  The picked cotton then needs to be cleaned in a process that “removes any stalks, leaves and other matter”(Tokens)  in a cotton gin, again utilizing mechanical energy. Once cleaned, the cotton can go straight to the carding process to be untangled and rid of any general fiber impurities in a carding machine, utilizing more mechanical energy (Mulrooney). Because it does not have to go through the retting process, cotton processing saves itself the extra mechanical labor as well as water resources that hemp must use. From there, the cotton and hemp fibers can be spun together in a “rotor spinning system”(Ahmed) to create a hemp cotton blend yarn that can then be advanced to the next stage of production, fabric manufacturing. 

After the blended cotton hemp yarn is fully produced, fabric manufacturing can begin. The yarn can be woven on a loom to create a fabric textile. Generally textiles that are made specifically for mass manufacturing a product are made on automatic looms that are very efficient, as “ only the conditions such as yarn type and weave width need to be input in order for the optimum operations to be performed” (History of Automatic Loom). Therefore, the weaving process of a blended hemp cotton textile requires mostly mechanical energy, and then the textile can be used to create the backpack. 

The zippers are also manufactured by a company called YKK, a zipper company that supplies much of the zippers found on clothes and other fashion items. According to the company, the yearly expense of energy across all of its factories is 499.65 million kWh of electricity. 

Hemp cotton blend textile backpacks are not an extremely mainstream style of bag, so much of the manufacturing of the bags themselves come down to hand sewn bag assembly. In comparison, more mainstream and popular mass produced backpacks like cotton backpacks may be sewn using more automated machinery along with human labor, making a non hemp blend bag that consumes more unsustainable energy. 

Many of the raw materials to create a hemp cotton blended yarn are found in other countries and are transported to different locations at different stages of the processing and manufacturing stages of the backpack’s product life cycle. China is the leading global producer of industrial hemp (Schmid) so the hemp crop used for blended textiles will most likely be sourced from China, while cotton will most likely be found from the “cotton belt” in the Southern United States (How Cotton is Made). From there, both materials must be transported to China or Hungary where the majority of the world’s water retting occurs (Industrial Hemp in the United States: Status and Market Potential), and so the embodied energy to transport the materials between continents expands, as the materials would theoretically be transported via ship, train, or plane. In comparison, since cotton is sourced domestically in the United States as previously mentioned, a cotton backpack without any hemp can be produced and manufactured locally, which could cut down on transportation energy usage in comparison to the blended backpack’s transportation requirements. 

A core strength of the blended cotton hemp textile backpack over a non blended cotton backpack is its durability and general adoptions of the strengths of hemp textiles, as “Blending hemp into yarn can impart some of the qualities of that fiber, including strength and anti-microbial properties, and takes advantage of existing infrastructure” (Wenner). Because of this, a blended textile backpack will need to be replaced much less often than a cotton backpack and so the overall energy in the creation and disposal of the backpack should theoretically be less than that of a cotton backpack. The consumer will also need to expend less energy having to maintain and wash the backpack as its durability and ability to withstand mold and mildew formation (Why Wear Hemp? the Benefits of Wearing Hemp Clothing).

As a blended material, the cotton and hemp in the textile must be separated from each other in order to be effectively recycled. This can be achieved with chemical recycling, which “uses a series of chemical processes to separate and recycle non-homogenous waste streams” (Cattermole). However, this process is very energy intensive and is not a fully developed or widely used process in terms of textile recycling. As a result, backpacks with this blended textile will mostly end up in landfills or incinerators, which is a very unsustainable outcome for these products. However, cotton is also not biodegradable, so a fully cotton bag will face the same result. 

Hemp as a material is a step forward in the world of sustainable production, but not every facet of hemp in its incorporation into everyday products such as backpacks is completely sustainable or even comparably better than other more traditional materials like cotton. Despite this, more research and incorporation of new innovative materials should be explored, as certain characteristics of hemp fibers and yarn genuinely could contribute to a more sustainable and circular product life cycle. 

Ahmed, A T M Faiz, et al. “Hemp as a Potential Raw Material toward a Sustainable World: A Review.” Heliyon, U.S. National Library of Medicine, 13 Jan. 2022, www.ncbi.nlm.nih.gov/pmc/articles/PMC8819531/.

Assoune, Alex. “Is Hemp Fabric Biodegradable.” Panaprium, Panaprium, 16 Oct. 2020, https://www.panaprium.com/blogs/i/hemp-biodegradable.

Baxter, W. J. "Growing Industrial Hemp in Ontario." Omafra.gov.on.ca. N.p., Aug. 2000. http://www.omafra.gov.on.ca/english/crops/facts/00-067.htm#harvesting

Cattermole, Amanda. “Chemical Recycling Separates Blended Textiles!” Cattermole Consulting Inc., 2 Mar. 2020, https://www.cattermoleconsulting.com/chemical-recycling-separates-blended-textiles/ 

Cholia, Ami. “The Top 5 Reasons Why We Should Grow Hemp.” HuffPost, HuffPost, 24 Sept. 2014, https://www.huffpost.com/entry/the-top-5-reasons-why-we_n_253348.

“Cotton: From Field to Fabric.” Cotton.org, National Cotton Council of America, https://www.cotton.org/pubs/cottoncounts/fieldtofabric/fabric.cfm.

"Hemp Textiles in Britain." Hemp Textiles in Britain. N.p., n.d. http://www.ukcia.org/industrial/hemptextilesinbritain.php

“History of Automatic Loom.” Automatic Loom, Yoshida Machinery, http://www.yoshida-mc.co.jp/history/loom.htm.

“How Cotton Is Made.” How Products Are Made, http://www.madehow.com/Volume-6/Cotton.html.

“How Much Energy Does It Take (on Average) to Produce 1 Kilogram of the Following Materials?” Low-Tech Magazine, https://www.lowtechmagazine.com/what-is-the-embodied-energy-of-materials.html 

 "Industrial Hemp in the United States: Status and Market Potential. (Section-Harvesting, Retting, and Fiber Separation)" Ers.usda,gov. USDA ERS, Agricultural Economic Report No. (AGES-001E) 43 pp, Jan. 2000. http://www.globalhemp.com/wp-content/uploads/2000/01/ages001Ee.pdf

Kozlowski, R., et al. “Processing of Hemp Fiber in Blends with Cotton for Apparel Fabrics.” 2003, https://www.icac.org/Content/EventDocuments/PdfFilesced6a9b1_0a1f_41bb_b709_52b35a851cf0/Processing%20of%20hemp%20fiber%20in%20blends%20with%20cotton%20for%20apparel%20fabrics.pdf. Accessed Mar. 2023.

"LOW-TECH MAGAZINE." 'LOW-TECH MAGAZINE' N.p., n.d. http://www.lowtechmagazine.com/what-is-the-embodied-energy-of-materials.html

McLaren, Warren. "YKK Recycled and Biodegradable Zippers." TreeHugger. N.p., 2 May 2008. http://www.treehugger.com/green-architecture/ykk-recycled-and-biodegradable-zippers.html

Mulrooney, Thomas. “How Cotton Fabric Is Made: Carding & Combing Cotton: Vision Linens.” How Cotton Fabric Is Made: Carding & Combing Cotton | Vision Linens, Vision Linens, 2 Mar. 2022, https://www.visionlinens.com/blog/cotton-fabric-manufacturing-part-2-carding-and-combing-the-cotton.

Schmid, Lea. “Hemp around the World - Countries to Watch in the Growing Industry.” Signature Products Blog, Signature Products Blog, 29 July 2022, https://blog.signature-products.com/hemp-around-the-world/.

Schwartz, Fredric. “Choosing Hemp Fiber - Eco Friendly Fabric since 8000 B.C.” Fibre2Fashion, July 2010, https://www.fibre2fashion.com/industry-article/5016/hemp-fiber-eco-friendly-fabric.

Tokens, Eve. “How Is Cotton Made into Fabric?” The Creative Curator, 28 Nov. 2022, https://www.thecreativecurator.com/how-is-cotton-made-into-fabric/.

Tuffman Equipment. “Hemp Processing: Tuffman.” Tuffman Equipment, 3 Sept. 2021, https://www.tuffmanequipment.com/hemp-processing/#:~:text=Hemp%20processing%20for%20hemp%20fibers,be%20used%20in%20different%20applications 

Wenner, Nicholas. “Weaving Hemp into the Northern California Fibershed .” Resilience, Post Carbon Institute, 22 Jan. 2020, https://www.resilience.org/stories/2020-01-22/weaving-hemp-into-the-northern-california-fibershed/.

“Why Wear Hemp? the Benefits of Wearing Hemp Clothing.” Hemp Clothing Australia, https://www.hempclothingaustralia.com/why-wear-hemp#:~:text=Breathable%20%26%20insulating,the%20fabric%2C%20not%20against%20it.

Waste/ pollution paper:

Cassie Ngo 

Professor Cogdell 

DES 40A 

16 March 2023 

Life Cycle of Hemp Backpacks - Waste 

To bridge the gap between the limited supply of natural fibers and the increasing demand for textile fibers, multiple industries have been forced to shift towards synthetic fibers. This phenomenon has affected the backpack industry, as more polyester and nylon backpacks are being manufactured. However, backpacks made of hemp are making a presence in the industry with around 3000 backpacks produced each month. Hemp backpacks mark a potential step forward to reversing the shift back to natural fibers and towards a sustainable future. In fact, hemp backpacks are not completely made of hemp but actually use a hemp and cotton blended fabric. Although growing hemp is known to be a sustainable process, hemp backpacks are wasteful to manufacture and recycle due to the hemp and cotton blended fabric. 

Although growing hemp has a low environmental cost, growing cotton and creating aluminum for the zipper increases the environmental cost significantly in the raw material acquisition phase. Cotton is a water intensive crop, “result[ing] in 1-6% of the world’s total freshwater withdrawal” (Baydar). Although irrigation methods have been developed to decrease water consumption and increase crop yield, high levels of salt in the irrigated water can enter the soil and salinize the soil, rendering the soil unusable and damaging its natural fertility. Soil that has grown cotton can eventually become wasteland, resulting in the destruction of farmland. Cotton also has poor nutrient uptake efficiency, requiring the use of synthetic fertilizers. In

addition, large quantities of toxic pesticides and herbicides are needed to protect cotton from insects and weeds, leading to nitrogen and phosphorus emissions. Due to the major use of water and toxic chemicals, fertilizer and pesticide runoff can contaminate and pollute freshwater sources. 

While cotton cultivation is responsible for 220 million metric tons of carbon dioxide per year, hemp is even more effective than trees in carbon sequestration as “one hectare of industrial hemp can absorb 15 tons of CO2 per hectare” (Wilson). Moreover, less water and land is required to grow hemp. “4.23 litres of H2Oe are required to produce hemp and 57.1 litres of H2Oe for the same amount of cotton” (“The Advantages and Disadvantages of Clothing Made from Hemp”). Since hemp grows in high densities, hemp not only needs less land but also no herbicides. Although hemp needs less pesticides due to its natural resistance to insects, it requires more nitrogen fertilizer than cotton production. Since used in excess, nitrogen fertilizers can release nitrous oxide into the atmosphere, a greenhouse gas that contributes to global warming and threatens global biodiversity. Both hemp and cotton are harvested with combine harvester machines powered by gasoline engines. Although exhaust emissions are made visible through smoke, combine harvesters also release other pollutants, including noise and dust, which is a component of atmospheric particulate matter. 

To produce aluminum for the zipper, aluminum must be extracted from the raw material bauxite. Mining bauxite ores releases excessive amounts of dust, adding onto the net particulate waste. Dust control measures are instilled by adding water; however, this water is drained and becomes wastewater. Fortunately, the wastewater is treated with lime and can be put back into

streams. Bauxite refineries then generate extreme amounts of waste, specifically “about one ton of solid waste during the production of a ton of aluminum” (“Aluminum Production Wastes,” 2014). This solid waste consists of muds, which emit radioactive chemicals including thorium, radium, and uranium. After the alumina is extracted from the bauxite, electricity processes the alumina to create aluminum metal, producing carbon dioxide emissions. Aluminum is overall responsible for “about 3% of the world’s 9.4 Gt of direct industrial CO2 emissions in 2021” (Hodgson). Even though growing hemp is significantly more sustainable than cotton and aluminum production, all materials are required to create a durable fabric and zipper. 

The manufacturing of backpacks is wasteful notably in its fiber processing and spinning stages. To create a durable hemp and cotton blended fabric, the cotton and hemp fibers must be processed. First, the cotton is fed into a cotton gin, which separates the seeds from the fibers. “The full significance of cotton ginning activity is realized when one considers that up to 1500 lbs. of waste (burrs, motes, trash, and lint) can be produced for each bale of cotton ginned” (Stanko). In some instances, this waste is burned, and specifically, smoke from burning burrs was found to contain tars and arsenic, which can cause adverse health effects to those near cotton plants. Immense amounts of dust and particulate matter are also emitted from cotton gins with “as much as 76,000 Mgms. per cubic meter of air sampled” (Stanko). Then, the pure cotton fibers are mechanically carded to form long strands of cotton through machinery that releases carbon dioxide emissions. 

The hemp fibers are cottonised to give it the ability to blend it with cotton fibers through the following process: retting, decortication, and carding. First, the hemp fibers must be

separated from the stem by breaking down the pectin that binds them together through a process called retting. The two most popular methods of retting are chemical retting and water retting. Although frequently used due to its efficiency and uniform fiber output, chemical retting involves immersing the plant “in a bath containing about 0.5% of hydrogen peroxide, 0.5% of ammonium phosphate, and 1% of urea” (“Chemical Retting Process of Producing Bast Fibers”). In addition to these toxic chemicals, hydrogen sulfide and methane are byproducts of the decaying of the hemp plant material. This highly contaminated wastewater rich in biological waste and chemicals must be disposed of and can cause critical environmental damage. In water retting, stalks of hemp are submerged in rivers or ponds, where anaerobic bacteria can break down the stalks. As the bacteria decomposes the plant material, it releases methane and carbon dioxide, causing microbial water pollution. The wastewater is then rendered unusable for human and animal consumption and damages the ecosystem. To prevent damage to ecosystems, water tanks can replace rivers or ponds. Although this requires high water consumption and energy to heat the water, the wastewater can be treated and then reused as liquid fertilizer. Then, the hemp fibers must be decorticated, where the bast fibers (long fibers) are separated from the hurd fibers (short fibers). Finally, the bast fibers are carded into strands. Both decortication and carding are largely mechanical processes, and according to an EPA report, “off-road agricultural equipment released about 100,000 metric tons of carbon dioxide equivalent in 2019” (Heller). 

The hemp and cotton fibers can now be spinned to form yarns using a ring spinning or rotor spinning method. Blending hemp with cotton fibers actually reduces its spinning difficulties due to its pectin content. Workers in spinning mills are subject air polluted to dust and other fibrous particles. “In spinning mills, the extent of cotton dust contamination varies from

section to section, as it is worst in the blow room and minimum at the cone winding section” (Subrata Das). The operation of the spinning machinery can also cause noise pollution with noise levels up to 70 to 100 dB. 

To manufacture the zipper, strips of aluminum wire and strips of cotton are inserted into the teeth machine, where the aluminum is cut into teeth and is embedded into the fabric. Excess bits of aluminum and remainders of the cotton are cut off, creating solid waste. According to the YKK Group (a leading manufacturer of zippers), “the output of carbon dioxide emission was 393,000 tons. Nitrogen oxide emissions were 58 tons. Sulfur oxide totaled to thirty tons. Wastewater was calculated to be 13.5 million cubic meters. 88,962 tons of wastes were disposed. Finally, 87,834 tons of wastes were recycled” (Chang). Factory workers hand stitch the backpack together, so there are no emissions in the construction of the backpack. 

Since these factories are located in Nepal, numerous modes of transportation, including planes, trucks, boats, and trains, are needed in order to distribute the backpacks to retailers worldwide. “Emissions of carbon dioxide in the transportation sector accounted for 38 percent of energy-related emissions in the United States in 2021—the largest share of such emissions of any sector of the economy” (“Emissions of Carbon Dioxide in the Transportation Sector”). 

Hemp backpacks require less maintenance due to the strength and durability of the backpack. The hemp and cotton blended fabric displays “better performance in moisture absorption, air permeability, anti-mold and antibacterial property, UV protection and antistatic properties” (Ahmed). The fabric also doesn’t stretch, maintaining the backpack’s shape and size.

Its rigid properties also allow the backpack to resist flammability and pilling. However, in the case the backpack does get dirty, it is suggested to hand wash the backpack with soap or detergent and not use a washing machine, resulting in less water waste. 

Despite its durability, the hemp and cotton blended fabric makes recycling the backpack more difficult. Since there is more than one material involved in the fabric, the extraction processes become more complex. However, many companies are researching and developing ways to separate blended fabrics and give them new life. For instance, the Hong Kong Research Institute of Textiles and Apparel has developed a hydrothermal process that utilizes heat, water, and biodegradable chemicals to separate fibers in blended fabrics but only has been tested on cotton and polyester blends. “From the perspective of the circular-flow economy, however, fiber blends are problematic because they cannot be recycled profitably” (Suntinger). 

Finally, the hemp backpack either ends up in landfill or incinerators due to its inability to be recycled or decompose. Although hemp and cotton are biodegradable, they have been treated with toxic chemicals in their manufacturing stage and blended together, which hinders both of their biodegradability. Incineration of the backpack would generate fossil fuel and carbon dioxide emissions into the atmosphere. 

Even though hemp is widely known as a natural and sustainable resource, it is depleted of its sustainability in the end when processed into a hemp and cotton blended fabric for a backpack. This raises the question if hemp backpacks are truly a step forward towards a sustainable future as it is advertised. As the life cycle of hemp backpacks stay linear with a

wasteful disposal process, in the near future with recent technological developments, this life cycle could transform from linear to circular. 

.

Works Cited 

Ahmed, A T M Faiz, et al. “Hemp as a Potential Raw Material toward a Sustainable World: A Review.” Heliyon, U.S. National Library of Medicine, 13 Jan. 2022, 

www.ncbi.nlm.nih.gov/pmc/articles/PMC8819531/. 

Beall, Abigail. “Why Clothes Are so Hard to Recycle.” BBC Future, BBC, 24 Feb. 2022, https://www.bbc.com/future/article/20200710-why-clothes-are-so-hard-to-recycle. 

Chang, Claudia. “Zippers - Design Life.” Design Life Cycle, Mar. 2014, 

www.designlife-cycle.com/zippers. 

“Chemical Retting Process of Producing Bast Fibers.” Google Patents, Google, https://patents.google.com/patent/US2457856A/en#:~:text=A%20chemical%20retting%20proces s%20of,%2C%20and%201%25%20of%20urea. 

“Department of Health.” Important Things to Know About Landfill Gas, 

www.health.ny.gov/environmental/outdoors/air/landfill_gas.htm#:~:text=Methane%20and%20ca rbon%20dioxide%20make,bacteria%20break%20down%20organic%20waste. 

“Emissions of Carbon Dioxide in the Transportation Sector.” Congressional Budget Office, https://www.cbo.gov/publication/58861. 

G. Baydar a, et al. “Life Cycle Assessment of Cotton Textile Products in Turkey.” Resources, Conservation and Recycling, Elsevier, 17 Oct. 2015, 

www.sciencedirect.com/science/article/pii/S0921344915300677. 

Haufe, Juliane, and Michael Carus. "Hemp Fibres for Green Products - An Assessment of Life Cycle Studies on Hemp Fibre Applications." European Industrial Hemp Association 1 (2011): 6. Print. https://www.votehemp.com/PDF/11-07-07_META-LCA_Hemp_Fibre_Products.pdf 

Hayo M.G. van der Werf, et al. “The Environmental Impacts of the Production of Hemp and Flax Textile Yarn.” Industrial Crops and Products, Elsevier, 9 July 2007, 

www.sciencedirect.com/science/article/pii/S0926669007000775. 

Heller, Marc. “Climate Change Fuels Drive toward Cleaner Tractors.” E&E News, 7 Dec. 2021, https://www.eenews.net/articles/climate-change-fuels-drive-toward-cleaner-tractors/. 

Hodgson, David, and Tiffany Vass. “Aluminium – Analysis.” IEA, 

https://www.iea.org/reports/aluminium. 

Lawson, L., et al. “[PDF] Cellulose Textiles from Hemp Biomass: Opportunities and Challenges: Semantic Scholar.” Sustainability, 1 Jan. 1970,

www.semanticscholar.org/paper/Cellulose-Textiles-from-Hemp-Biomass%3A-Opportunities-La wson-Degenstein/f7d31ffa5c34cccaf4690ff1da3f922262577a83. 

Stanko, James J., et al. “Some Air Pollution Problems Associated with Agriculture in Texas.” Journal of the Air Pollution Control Association, vol. 18, no. 3, 1968, pp. 164–165., https://doi.org/10.1080/00022470.1968.10469110. 

Subrata Das, Dr. “Environmental Aspects in Textile Industry: Ecological Hazards and Remedial Measures - Page 2 of 6.” Textile School, 20 June 2019, 

https://www.textileschool.com/5293/environmental-aspects-in-textile-industry-ecological-hazard s-and-remedial-measures/2/. 

Suntinger, Hildegard. “Recycling Textiles - Even If the Natural Fibres Are Mixed with Plastics.” Innovation Origins, 20 July 2020, 

https://innovationorigins.com/en/recycling-textiles-even-if-the-natural-fibres-are-mixed-with-pla stics/. 

“The Advantages and Disadvantages of Clothing Made from Hemp.” COSH!, cosh.eco/en/blog/materials-the-environmental-benefits-of-hemp. 

Which Fabrics Can Actually Be Recycled, and Why Does It Matter? 

www.wellmadeclothes.com.au/which-fabrics-can-actually-be-recycled-and-why-does-it-matter/. 

Wilson, Catherine. European Industrial Hemp Association. 

https://ec.europa.eu/environment/forests/pdf/respondents-additional-inputs/European%20Industri al%20Hemp%20Association%20(EIHA).pdf. 

Zhao, Megan. “H&M Foundation-Backed Research Finds New Way to Recycle Blended Fabrics.” S&P Global Homepage, 21 Sept. 2017, 

https://www.spglobal.com/marketintelligence/en/news-insights/latest-news-headlines/h-m-found ation-backed-research-finds-new-way-to-recycle-blended-fabrics-41970154. 

Zheng, Zhonghua, et al. “A Narrative Review on Environmental Impacts of Cannabis Cultivation - Journal of Cannabis Research.” BioMed Central, BioMed Central, 6 Aug. 2021, jcannabisresearch.biomedcentral.com/articles/10.1186/s42238-021-00090-0.