Sharmon Lebby is a writer and sustainable fashion stylist who studies and reports on the intersections of environmentalism, fashion, and BIPOC communities.
Throughout history, representations of luxury and wealth have dominated the fashion industry. As a result, many materials now mimic extravagance but at a fraction of the cost by using different, less expensive fibers. Cupro is one example because it is produced from cotton industry waste. While that may sound eco-friendly, a big question remains: Why is cupro illegal to produce in the United States? Twill Cotton
Here, we unpack the history of cupro production, its popularity, and whether or not it is a sustainable fabric choice.
Cupro is short for cuprammonium rayon; it gets its name because the solution of copper and ammonia is used to make this particular type of rayon. Rayon, a regenerated plant-based material, was created as an alternative to silk and rose in popularity because of its lower price point.
Cupro is what one would consider a semi-synthetic fabric. Cellulose is taken from cotton linter and washed. Next, it is dissolved in a solution of cuprammonium hydroxide, which is then filtered to remove any undissolved substances using asbestos and sand. The final solution is spun into fibers that are passed through a bath of diluted acid, alcohol, and a cresol solution. The outcome is regenerated cellulose filaments.
There are several different types of regenerated cellulose fibers, and viscose rayon accounts for 90% of them. Viscose rayon can be created from tree pulp, bamboo, or the cotton linters that produce cupro.
Cupro is marketed as sustainable because it is a byproduct of the cotton industry. Yet cotton is not a perfect crop—its substantial use of water and pollution caused by agrochemicals has built up a high environmental impact on farmlands and the surrounding ecosystems.
Because of the hazardous chemicals used in the manufacturing process, the production of cupro in the United States is currently illegal. While ammonia, sodium hydroxide, and sulfuric acid are not found in the final fabric product, the safety of workers handling these chemicals must be taken into account. Cupro that isn't created using a closed-loop system also poses the risk of contaminating areas with copper waste.
Though cupro is derived from a natural source, it is mixed with various chemical solutions to create a fiber that can be woven—this is what makes it semi-synthetic and places it right in the middle of fully natural fibers, like cotton, and completely manufactured ones, like polyester.
Even though they are essentially made from the same plant, cupro and cotton are two very different fabrics. The main difference between them is the resulting feel. The small fibers leftover on the seed goes through a chemical process that leaves them feeling soft and silky. This is what allows cupro, like other rayon fabrics, to be seen and used as a vegan alternative to silk.
Cotton, on the other hand, is a more versatile fabric. There are several different types of materials that can be made from cotton depending on the weaving style. Despite the issues associated with conventional cotton, cupro requires 70% more energy to produce than natural cotton.
Polyester, the most widely used fabric, is a synthetic material that requires the use of fossil fuels. This fabric requires very little time to produce and is made and sold at relatively lower costs than other fabrics. Polyester does not have the same soft feel that is associated with natural fibers.
Cupro, in contrast, is regaled for its softness and draping capabilities. It is also difficult to dye, requiring even more harsh and toxic formulas to complete the process. It does, however, require much less water.
Produced exclusively in China, cupro is becoming less popular due to the expense and environmental factors. If you are looking for vegan alternatives to mainstream fabrics, there are several, more eco-friendly options to consider.
Modal is a type of elevated rayon that is likened to silk. It is derived from the cellulose pulp of trees. One study has shown that modal has lower environmental impacts (40-80%) than other fabrics with regards to the dyeing process. They also require less energy than cotton to produce.
For an even greater dose of sustainability, choose items made from Lenzing (formally Tencel) modal. These branded materials are known specifically for sustainably sourced raw materials and closed-loop production systems.
Microsilk, manufactured by Bolt Threads, is still in the research and development stage but has done collaborations with Stella McCartney and Best Made Co. to produce limited edition items. The lab-produced fiber is made by fermenting sugar, yeast, and water. Microsilk is protein-based, similar to silk and other animal-based materials. It specifically imitates spider silk.
Orange fiber is exactly what it sounds like; like Piñatex and apple leather, it is made from the waste of the fruit it is named for. Orange fiber is an innovative textile not yet commercially available, but brands such as H&M, Salvatore Ferragamo, and E. Marinella are producing collections made from this fiber. Model and actress Karolina Kurkova even wore a dress of orange fiber at the Green Carpet Fashion Awards.
China is the biggest producer and exporter of cupro. There, the fabric is often referred to as ammonia silk. It's also produced in Japan.
Even though production of it is legal, you can still find cupro exported from Asia sold in the U.S.
Yes, cupro is biodegradable because it's made entirely of plant-based materials. It's even been called an eco-friendly viscose alternative—it's just the toxic production process that puts the environment and factory workers at risk.
Sayyed, Anwar J., et al. "A Critical Review of the Manufacturing Processes Used in Regenerated Cellulosic Fibres: Viscose, Cellulose Acetate, Cuprammonium, LiCl/DMAc, Ionic Liquids, and NMMO Based Lyocell." Cellulose, vol. 26, 2019, pp. 2913-2940., doi:10.1007/s10570-019-02318-y
Rana, Sohel, et al. "Regenerated Cellulosic Fibers and Their Implications on Sustainability." Roadmap to Sustainable Textiles and Clothing, 2014, pp. 239-276., doi:10.1007/978-981-287-065-0_8
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