The HALO-TEX project has published a new report on the functional requirements of bio-based textile additives. By combining sustainability goals with performance targets, and aligning with established international standards, the project aims to ensure that the developed textile coatings are suitable for real-world applications, bridging the gap between laboratory research and practical, scalable solutions.
Developed within the HALO-TEX project, this report reviews the scientific and commercial landscape of lignin- and polyphenol-based textile materials. It covers how these materials bond with textile substrates, the methods used to apply them, the properties they confer, and their current level of technological readiness. The report also considers their role in improving environmental sustainability and reducing health risks, and sets out the functional requirements, UV resistance, antimicrobial activity, and flame retardancy that guide the development of bio-based textile additives within the project.
Context: Why the textile industry needs bio-based alternatives
As the report describes, the textile sector is undergoing a big structural change, driven by tighter environmental regulations, sustainability commitments from global brands, and greater consumer awareness of the health and environmental impacts of textile products. Properties such as antibacterial activity, UV protection, antioxidant effects, and flame retardancy have long been achieved using fossil-based chemicals or metallic nanoparticles, such as silver and titanium dioxide, approaches that, according to the report, carry significant drawbacks, including toxicity risks, poor biodegradability, and the release of harmful substances during washing.
In response, the report points to growing interest in bio-based, renewable materials that align with regulatory frameworks such as REACH, ZDHC, and the EU Green Deal. This report serves as the guiding reference for all subsequent formulation and coating activities.
Lignin and polyphenols: Key bio-based materials
HALO-TEX focuses on two families of bio-based compounds: lignin and polyphenols.
Lignin is a naturally occurring aromatic polymer obtained as a by-product of the pulp and paper industry. According to the report, its inherent capacity to absorb UV radiation, its antioxidant and antimicrobial properties, and its char-forming behavior make it a strong multifunctional candidate for textile finishing. Lignin-based coatings have shown the ability to provide UV protection, antimicrobial activity, flame retardancy, and water repellence on textile substrates. The global lignin market stood at around USD 1.32 billion in 2024, yet the report notes that no lignin-based finishing product is currently available commercially, with textile applications still predominantly confined to research and pilot-scale projects.
Polyphenols are naturally occurring compounds present in bark, roots, leaves, fruits, seeds, and various agro-industrial by-products. The report explains that their phenolic hydroxyl groups allow them to form both non-covalent bonds, such as hydrogen bonds, electrostatic interactions, and π–π interactions, and covalent bonds with natural fibers like cotton, wool, and silk. Among the various polyphenol families, flavonoids and tannins are particularly relevant for textile applications due to their antimicrobial, antioxidant, and UV-absorbing properties. Studies reviewed in the report show strong antibacterial activity against Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa in fabrics treated with polyphenols from plant by-products such as mango seeds and feijoa peels.
Performance requirements and testing standards
The report identifies three core functional properties and the standards used to evaluate them.
UV protection is quantified through the Ultraviolet Protection Factor (UPF). According to the report, a UPF above 30 indicates very good protection, while values above 50 are rated excellent. To achieve this, HALO-TEX uses lignin nanoparticles, whose aromatic structure enables them to absorb and dissipate UV radiation.
Flame retardancy is assessed by measuring how long a fabric withstands direct exposure to fire under controlled conditions. The report establishes that a burning time of 20 seconds or more qualifies a fabric as non-ignitable, an essential criterion for protective clothing and interior furnishings. Micro- and nanofibrillated cellulose is the active component used here, creating physical barriers that hinder flame propagation.
Antibacterial activity reflects a fabric's capacity to limit microbial growth. As the report describes, textiles are grouped into three performance levels, low, moderate, and high, and HALO-TEX's polyphenol-based coatings are designed to reach at least a moderate level, with higher performance sought for medical and high-contact end uses.
The report also benchmarks these targets against commercially available textile finishing products.
Conclusions
The report concludes that lignin- and polyphenol-based materials offer a credible alternative to conventional textile treatments, owing to their natural origin, range of functional properties, and capacity to bond effectively with textile fibers. A key advantage highlighted in the report is the possibility of obtaining these compounds from agro-industrial waste streams, including peels, seeds, bark, and processing residues, which supports waste reduction and a circular economy approach. The report adds that the use of eco-friendly extraction methods further reduces environmental impact and limits the need for hazardous solvents.
Among the main challenges noted in the report are the structural variability of lignin, limited durability after washing, and the absence of standardized production processes. Progress in lignin fractionation, nanoparticle development, and hybrid bio-based systems is expected to bring these materials closer to commercial viability, opening significant opportunities for innovation in sustainable, multifunctional textile solutions.
Read the full report here