Although several companies have seaweed-enhanced textiles in the market, none of them actually contain a high amount of seaweed. At the moment, spinning fabric with a high seaweed content is not financially and technically viable.
However, seaweed could potentially become more relevant as a source material for the textile industry in the future. To make this happen, seaweed farming needs to scale up, while new fibre spinning techniques need to be developed to make the most of the raw materials.
Including seaweed in textiles would improve sustainability by replacing land-based biomass or petroleum with a marine source, and add the potential beneficial health functions of seaweed to consumer and industry textiles.
For this article we’ve leaned heavily on a 2019 report for the Taretekstil project carried out by Ocean Rainforest and Kolbrun. It’s worth reading in its entirety if you would like to delve deeper.
How seaweed yarns are made
Cellulose-based
Viscose is a thread made from the cellulose in wood pulp. It was traditionally produced using harsh chemicals, but new techniques like lyocell and Ioncell use substances that are much less harmful. Finnish start-up Spinnova has even managed to eliminate all chemicals.
Since all plants contain cellulose, the possibility exists to make viscose from all kinds of vegetal materials, including seaweed. Unlike trees, though, which average around 40-50% cellulose content, seaweed only contains roughly 6% cellulose.
Techniques like lyocell need a pulp with a high cellulose concentration. This means that all seaweed viscose to date only has a small percentage of actual seaweed in it.
In the future, a cascading seaweed biorefinery could squeeze out a seaweed pulp with a high cellulose concentration that could then be used in a lyocell process to make real seaweed viscose (>70%). Right now, neither the processing technology, nor the industrial-scale seaweed farming necessary to supply the raw materials are in place yet.
Alginate-based
One company is taking a different approach. AlgiKnit is working on producing yarn from alginate combined with other renewable biopolymers. In contrast to cellulose, alginate can make up to 1/3 of the total mass of certain seaweed species.
The downside is that while seaweed cellulose is a waste product with no current usage, alginate already has many different applications. Alginate is even already woven into textiles for medical wound dressings, although the characteristics of this type of alginate fibre are not considered well-suited for traditional textiles and clothing.
Nonetheless, the results look promising, and Algiknit has received 2.2 million dollars in seed funding from SOSV, Horizons Ventures and RebelBio.
Health benefits
Not many clinical trials have been done, but early results indicate that the seaweed-enhanced lyocell textiles on the market today have antibacterial and antioxidant properties, which would make them especially suitable for people with skin diseases.
Something to keep in mind is that fashion brands often weave their own fabrics, mixing for instance 20% seaweed-enhanced lyocell with 80% cotton, further diluting the amount of seaweed in the final fabric to less than 1%. It’s unclear right now how much seaweed is necessary to get beneficial health effects.
Producers and patented fabrics
The most popular fabric is SeaCell, where dried and ground Ascophyllum nodossum harvested in Iceland is added to the cellulose of wood pulp with the lyocell process. Made by Smartfiber, the final fibres are composed of approximately 4% seaweed.
Vitadylan, based in Germany like Smartfiber, has a similar process, also using Ascophyllum nodossum harvested in Iceland, with about 10% of seaweed in the finished product.
Celp, by The Fabric Workshop, is still in development, but seems to rely on a similar process of lyocell with added seaweed.
Seaweed Yarn creates yarn from seaweed harvested in the Netherlands. Not sure how. The start-up has entered an accelerator to validate its ideas.
We already discussed Algaknit, who are using a process based on alginate instead of cellulose.
Designers
Textile designers that use seaweed extensively in their work are Violaine Buet, Jasmine Linington and Nienke Hoogvliet, who is also the co-founder of the aforementioned Seaweed Yarn start-up.