Advanced textiles that support energy conservation fill a growing need.
by Seshadri Ramkumar
While it upended normal activities, COVID-19 has provided opportunities to think about what is best for our future globally, in terms of health planning, climate change, energy infrastructure and inclusive economic growth. Textile materials are important components of the energy and sustainability equation, but many people are not aware of this.
Not long ago, the public, generally, knew little about the textile materials in products such as layered fabric face masks. That all changed people worldwide turned to wearing them regularly. There are many more applications—filter substrates and glass fiber mats, would be examples—that also play important roles in a sustainable and healthy future. Fibrous substrates contribute to energy savings, help with developing greener materials for a sustainable infrastructure and can even serve as energy harvesters.
Energy and economics
While the major cost component of a textile product is the raw material, it is estimated that about 6–10 percent of the cost of manufacturing is from energy consumption during manufacture. In the past few decades, the textile sector—from the production of raw materials to making garments—has been working to conserve energy to reduce the overall cost of manufacturing.
As the price of raw materials is primarily a fixed cost, there may not be much leverage available to save on expenses there. Furthermore, the prices of fibers (both natural and synthetic) are dependent on many variables. In the case of synthetics, such as polyester and polypropylene, the price is directly correlated with the price of oil. For natural fibers such as cotton, the price is dependent on many volatile factors, including the weather during that particular year. Therefore, textile businesses are more likely to focus on the manageable and variable costs, which includes energy.
Energy is the heart of manufacturing and hence process optimization, machinery maintenance and regular energy audits are essential. In conventional textiles, a spinning operation has several precursor processes, such as the blow room operation and carding, which involve heavy machinery. Proper machinery alignment and correct belt usage and maintenance will support energy conservation, and an energy audit can help mitigate inefficiencies.
Professional associations in the field are in a position to help the industry with information about how to save energy and manage costs. Coimbatore, India-based South India Textile Research Association has undertaken numerous energy studies and has made available useful educational material for the textile industry.
Mirza Khyum who has worked as a production officer in Thermax Check Fabrics Ltd, Bangladesh, says, “Since Bangladesh is the second-largest manufacturer of ready-made clothing in the world, the reduction of energy consumption in any phase of manufacturing can save enormous costs and resources. As a result, carbon emissions will be reduced to safeguard Mother Nature. Some factories are reusing the process waste to produce quality goods to advance the approach of conserving resources.”
The textile sector is making efforts to conserve energy as a way to cut manufacturing costs, but also to be good stewards of the environment. Process optimization steps starting with raw materials can make a significant difference in the larger energy use picture. In the case of natural fibers, precision agriculture to conserve on chemical use, such as herbicides and pesticides—and more importantly, water—is being practiced.
West Texas, one of the world’s leading cotton producing regions, has been a pioneer in growing cotton and other rotation crops with less resources. The majority of the cotton crop grown there is dryland, which depends on rain during the growing season. Even in places of irrigated production, that irrigation is supplementary.
Producer support groups such as the Lubbock-based Plains Cotton Growers Inc. and state systems, including Agriculture Experimental Stations, regularly offer educational and outreach programs on water conservation as the water usage is directly related to water pumping and power use.
As part of its 10-year sustainability initiative, the entire U.S. cotton industry is endeavoring to enhance the efficiency of fiber production. The industry’s goal is to decrease energy use by 15 percent, which the cotton producers manage via a multi-pronged approach that includes reducing tillage and the use of nitrogen fertilizer. This goal also focuses on reducing greenhouse gas emissions by 39 percent, decreasing water usage by 18 percent, increasing land use efficiency by 15 percent and increasing soil carbon by 30 percent.
The range of textiles in the equation
Advanced textiles such as nonwoven mats find important roles in conserving energy. Glass fiber mats manufactured via carding and chemical bonding are used in insulating materials for homes and commercial buildings. These fibrous materials are common between roofing structures and the gypsum-based sheetrock sheets. The necessity of such insulation products has become clear after the recent power outage crisis due to winter storms in the State of Texas. One of the reasons for the failure was lack of adequate weatherization of the natural gas pipelines.
We may take for granted commonly used house infrastructure-related items such as blinds, but these play a vital role in conserving energy, and are indeed industrial textile products. Coated textiles such as PVC finished products find applications in many ready-to-build structures. Temporary shelters used as COVID-19 testing centers and vaccination sites were erected quickly and efficiently to deal with specific crises, without requiring the material and energy resources of a permanent structure.
There are many less obvious but equally useful products worth noting. The HVAC filters used in homes filter dust in the ventilation and humidity control pipes, thereby reducing the energy load and increasing the efficiency of heating and cooling units. Normally these pleated filters are made using bonded staple fiber nonwoven webs. Floor mats and carpets not only provide aesthetic value, but more importantly serve as insulating materials.
It is estimated that there are about 40 different textile-based items in an automobile. High loft nonwovens are used as heating, ventilation and acoustic insulators. Air filters and engine filters are necessary components to keep an automobile running. Automobile manufacturers are looking into utilizing recycled materials to replace metal components wherever possible to reduce the overall weight of an automobile. Industrial textile materials in an automobile, such as headliners, trunk liners and insulators help to reduce fuel consumption.
Textile substrates and composites are also used as energy harvesters. Windmill blades are relatively lightweight composites, made strong by using carbon fiber and other high-tech fibers for strength. Lithium-ion batteries use fiber-based separators to separate the anode and cathode electrodes. Cellulose based wet-laid materials are common separators, in addition to those made from natural and synthetic fibers.
Hollingsworth & Voce has been a pioneer in developing battery separators, building on its years of experience in the development of wet-laid nonwovens. LIELSORT® from Teijin utilizes microporous polyethylene to develop the separators. But with recent supply chain interruptions, one can expect developed economies to invest heavily in these advanced products to reduce dependency on other countries for the materials.
A way forward
The Biden Administration plans to invest about $1.2 trillion over eight years to rebuild infrastructure in the United States. This will offer an opportunity for using advanced and sustainable materials in building energy efficient structures. Particular attention is being paid to climate change in this initiative, which necessitates reduced greenhouse gas emissions throughout the process. Geosynthetics, insulation products and soft composites will be amply utilized in future construction projects, spurring more research and development. Because of these developmemts, manufacturers of advanced textile products can undoubtedly anticipate growth in the near future.
Seshadri Ramkumar, Ph.D., is a professor in the Nonwovens & Advanced Materials Laboratory, Texas Tech University, Lubbock.