Silk: Can We Dethrone the Queen of Fibers?
Silk is often called the “Queen of Fibers” known for being soft, supple, and lustrous. However, silk suffers from issues with its environmental footprint and animal welfare. Did you know that the Higg Index rates silk as the most environmentally damaging material used by the fashion industry based on factors such as global warming and water usage? Silk is considered one of the “thirstiest” materials - it is estimated that between 850 and 1000 tons of water is used in the production of one ton of raw silk. Further, many may be unaware that the majority of silk production relies on killing the silkworm to preserve the properties of the silk cocoon. Between 420 billion to 1 trillion silkworms are killed annually to produce silk. Perhaps it’s time for a cleaner, kinder Queen to take the throne.
In order for the fashion industry to shrink their environmental footprint, and reduce or eliminate its reliance on animals to produce silk, the supply chain needs viable, sustainable alternatives to silk. Right now, the current generation of silk replacements are typically synthetic fibers such as polyester, nylon, and cellulosics such as rayon. However, these replacements are riddled with their own sustainability issues: namely reliance on fossil fuels and contribution to microplastic pollution for synthetics, and deforestation, water, land, and chemical use for many cellulosics. This is where “next-gen” materials can make a big impact.
Next-gen silk innovations include:
(1) Precision fermentation, where microbial factories are capable of creating real silk protein, without the animal. The vast majority of this innovation involves the spider silk protein, instead of the silkworm protein which comprises commercial silk fabric. One of the most influential players is Spiber, who created Brewed Protein™ that can create the proteins that form silk, as well as cashmere or wool. Other notable players include Bolt Threads, AM Silk, Seevix, and Spidey Tek™.
(2) Tech which converts regenerative plants, plant waste, or algae into novel silk-like fibers. Notable players in this space include Orange Fiber, who extract cellulose from the waste of citrus juice processing, to create a soft regenerated fiber, SmartFiber AG, who include seaweed additives and zinc oxide in their cellulose-based lyocell fibers, and ENKA®, who makes a silky viscose derived from sustainably-sourced Northern European conifer trees.
Each of these categories of technology are poised to have lower environmental footprints than animal-derived silk, or its current synthetic replacements. In order for these and future innovations to be successful, innovators need to know the performance factors for silk they should target, and scientifically, how silk fiber came to have these unique properties.
Would you like to learn more about the ancient material that is silk, and the new wave of next-gen silk innovation? The Material Innovation Initiative will be publishing an upcoming report on “What Makes Silk, Silk?” that details the science behind silk’s luxurious properties, and the innovative strategies and opportunities to make animal-free, sustainable, high performance alternatives.
Here are just some of the unique aspects of silk:
-Silk is the only naturally occurring continuous filament fiber.
-Silk is known for having some pretty powerful engineering properties, which academic researchers have been trying to replicate for decades. Silk, particularly spider silk, is even stronger than steel!
-The unique luster, nearly a sparkle, that you see with silk fabrics, is due to silk’s unique microscopic structure - including that the fiber cross-section is naturally triangular in shape!
-Silk has unique interactions with water. Sometimes this is a positive - like wicking away perspiration for comfort in warm weather, but sometimes it is a negative - like the damage that can sometimes occur to silk fabric that is laundered in a washing machine.
-Notwithstanding that we should avoid farming wild animals, we actually can’t farm spiders for their silk because they are cannibals (who knew spiders could be even scarier than we thought!). The only way to make sufficient quantities of spider silk is with next-gen fermentation technology as described above.
This deep dive into the science and innovation surrounding silk will be publicly available through Material Innovation Initiative (MII) in a few weeks.This article was written for FashionUnited by Sydney Gladman, Ph.D., Chief Scientific Officer at Material Innovation Initiative