Cultivating hemp for textile fibre is an ancient practice, however with the advent of modern agriculture and the invention of synthetic textiles, the processing required for hemp meant it could not compete economically with these alternatives. Renaissance Fiber, a North Carolina clean-tech company, has developed an Ecologically Invisible hemp degumming method based on natural degradation of plant fibres observed in tidal streams, using far less energy than traditional hemp processing and creating hemp fibre that is more affordable and higher quality than other fibre types. At the same time, the process sequesters carbon in the effluent, which can be returned to the ocean as a natural carbon sink.
Renaissance Fiber is also one of The Biomimicry Institute’s top 10 nature-inspired startups selected to participate in the 2021 Ray of Hope Prize, a transformational program designed to help startups cross a critical threshold in scaling their sustainable solutions.
Founded in 2018, Renaissance Fiber produces American-grown, American-processed hemp fibre as the Renaissance Fiber solution for a sustainable textile industry.
Challenges of using Hemp for fibre
Cotton fibre comes from the flowers of the cotton plant (the boll), and consists of pure cellulose, free of any inherent contamination. It is common in many parts of the world to spin cotton almost directly from the plant. Commercially, cotton processing is more involved, with multiple steps, including chemical defoliation, harvesting, ginning (cleaning, de-seeding, and baling), and then milling. Nonetheless, all of this processing is simplified because cotton fibres are essentially yarn-ready. As a result, though, much of the textile infrastructure in the US is built around the properties of cotton fibre.
Hemp produces a high-quality bast fiber that provides rigidity to its stalk. It comes from the outer layer (skin, or phloem) of the plant’s stalk (like linen, ramie, jute & flax), and has played a large and important role in human history – rivaling flax as the chief textile fiber of plant origin until the middle of the 19th century. Humans have used hemp for thousands of years, with remains of hemp cloth dating back to the 5th millennium BC in China.
Hemp fibre is similar to cotton: they are both, in purified form, cellulose. Yet, hemp fibre, as part of the bast, plays a specific role vastly different than cotton (which, as stated, is simply the plant’s flower). It is therefore quite different from cotton in its natural form: 1) Hemp fibres are typically much longer than cotton. This can limit hemp’s availability in the US’s cotton-focused yarn infrastructure. 2) Hemp fibres have a different shape. This affects their behaviour in a yarn matrix. 3) In its natural form, hemp bast is not pure cellulose. Instead, hemp fibres are glued together as a natural composite to provide the strength for their role in stalk rigidity. This glue must be removed to some degree. Understandably, then, processing hemp fibre is fundamentally different than cotton.
Specifically, hemp fibres must undergo three processes:
1. Hemp fibre must be removed from the stalk. This is known as decortication. There is a wide range of decorticating machinery available. And since the output of decortication, in addition to fibre, includes the rest of the stalk’s material, we prefer to purchase and start with already decorticated material.
2. Hemp fibre must be separated from its glue, or gum. This is known as degumming. There are many known methods of degumming, and most come at high cost through fibre damage, high water and chemical inputs, and/or waste treatment.
3. Hemp fibre must be milled to appropriate lengths for use in a cotton or staple-length spinning facility.
Processing hemp into textile fibre presents challenging hurdles, and its past prohibition in the US (as well as the current focus on nutraceutical and pharmaceutical cannabis derivatives) leaves the techno-scape essentially wide open. While hemp has many sustainability benefits, these are undermined by inefficient, dirty or otherwise expensive processing solutions. It becomes critical, then, to rely upon technology that preserves the sustainable nature of hemp fibre.
Benefits of Hemp Degumming Technology
Renaissance Fiber’s patented solutions to hemp fibre processing are inherently clean:
- The technology is able to use non-potable water sources for fibre processing
- The waste is inherently ‘natural’, and is capable of being rendered ecologically invisible with little cost or effort
- The methods are accessible to a wide range of operational scales, from a small farm, to large production facilities and a wide range of input material qualities
- Post-processing can be done with standard textile machinery
The solutions are also inherently inexpensive:
- The material and energy overheads are low.
- Waste can be recovered as a valuable product or processed in with standard water treatment processes.
- Suitable non-potable water sources are abundant in the US Southeast, in close proximity to the ideal climate for growers and the US’s world-class textile industry.
