How to certify the bio-based content of textile materials

We already addressed the characteristics and the innovative nature of bio-based textile fibers here. Let’s briefly recall what bio-based fibers are.  The term 'bio-based' refers to materials or products that are made entirely or partly from biomass, including - but not limited to - plants, crops, vegetal waste, and aquatic plants. This concept is particularly relevant in the field of bioplastics, where biomass sources like corn, sugars, starches oil-rich seeds or cellulose serve as alternatives to traditional petroleum-based raw materials. In the textile industry, "bio-based" often pertains to the production of synthetic fibers, including nylon and polyester. Additionally, man-made cellulosic fibers, such as viscose, cupro, and acetate, fall under the bio-based category, given their derivation from biomass sources like wood and cotton.

 

Certifying bio-based textile materials involves various standards and labels designed to verify the bio-based content of products, typically determining the amount of bio-based carbon content in the product.  Radiocarbon analysis measures the ratio of carbon isotopes (carbon-14 to carbon-12) in a sample. Since carbon-14 is present in biomass but not in fossil materials, the proportion of carbon-14 indicates the percentage of carbon that comes from renewable biological sources versus fossil-derived sources. 

 

The accepted radiocarbon analysis method is outlined either in the ASTM D6866 or the EN 16785-1 or the ISO 16620-1 standard. All are accurate and reliable. The first two standard aligns with the regulatory and certification landscape of its region, the US for ASTM D6866, the EU for the EN 16785-1, making certain products more suitable for certification under one standard based on the target market. The ISO 16620-1 is tailored to deal with bio-based plastic materials – but in principle it can be used also with synthetic fibers such as polyester.

 

Existing certifications can have specific requirements, such as the minimum bio-based content needed and the testing methods used. We can identify three leading labels.

 

The United States Department of Agriculture (USDA) Bio Preferred Program is a wider government-led initiative designed to increase the purchase and use of bio-based products. That include a preference program in certain types of public procurements, a third party testing based on the ASTM D6866 to award a certification label and a financial support to agricultural sectors by creating new markets for agricultural products and residues. 

 

The TÜV AUSTRIA’s OK biobased certification program evaluates and rates the bio-based content of products on a scale from one to four stars, depending on the percentage of bio-based content one star for products containing 20-40% renewable carbon, two stars for 40-60%, three stars for 60-80%, four stars for 80-100%. This certification is applicable to a wide range of products, including textiles. The protocol was created using the ASTM D6866 radiocarbon analysis standard but is now transitioning to the EN 16785-1 with the evolution of mandatory requirement for certain products.

 

The DIN CERTCO certification label is based on European Standard EN 16785-1, recognized internationally, and applies to various products, including textiles, ensuring they contain bio-based material. It gives three different labels: Biobased 20%-50%, Biobased 50%-85% and Biobased >85%. Moreover, the material must be at least 50% organic.