The CELLFIL project aims to develop sustainable, high-performance Lyocell filament (LF) yarns and fabrics for diverse textile applications, including sportswear, automotive interiors, and technical reinforcements. During the first 18 months (M1–M18), the project focused on establishing the foundational processes for preparation and use of 2G feedstock, yarn production, functionalization, fabric development, and application testing. Significant progress was made across all work packages:
WP1 – Optimize Lyocell filament yarn production
WP1 focused on optimizing orange peel pulp production, validating alternative raw materials for LFY production, advancing automation, and improving process efficiency.
ORAN refined the orange peel pulp extraction process, enabling the production of three pulp batches for LENZ, who adjusted the viscosity to meet pulp requirements for pilot line production. LENZ evaluated multiple pulp types (ORAN pulps and textile recycling pulps) and produced two 2G based Lyocell filament types that met performance criteria.
NORD and LENZ developed and implemented automation solutions that enhanced spinning stability and reduced manual interventions.
While LFY specific recyclability tests were deferred, a broader Lyocell staple fiber recyclability study (LENZ and ADI) confirmed garment to garment recycling feasibility.
Process and resource optimization efforts, including a detailed heat and mass balance model, allowed to identify energy reduction potentials and established a framework for further technical and economic assessments.
WP2 – Yarn functionalization and processing to improve
WP2 addressed the enhancement of LF yarn versatility through twisting, covering, plying, and functionalization. Twisting parameters were optimized (600 TPM/8000 RPM for copsing, 900 TPM/8000 RPM for direct twisting), demonstrating the feasibility of direct twisting and reducing processing steps, costs, and environmental impact. Covering and plying trials produced high-quality yarns suitable for hosiery, sportswear, and reinforcement applications. Functionalization was achieved through the incorporation of TiO2 (0.7 %) to obtain a dull LFY, as well as CaCO₃ (up to 20 %) to evaluate high-loading additive feasibility and to enable a comparative assessment of the dulling effect relative to TiO2. Air texturization resulted in bulky yarns with satisfactory mechanical properties. However, durability under mechanical stress will require further optimization. Knitting trials demonstrated improved fabric uniformity and revealed an unexpected unique selling point: reduced creasing behaviour after washing compared with garments of comparable titers produced with 0 TPM and 1600 TPM. These developments provide a solid basis for downstream testing in WP3.
WP3 – LF fabric development exploiting textile
WP3 focused on producing fabrics from LF yarns while addressing performance, sustainability, and circularity. Knitting and weaving trials evaluated machine parameters and material performance, with LF yarn blends (wool, staple Lyocell, polyamide or elastane) mitigating limitations of pure LF yarns. Dyeing and finishing experiments, using natural and reactive dyes with metal salt mordants, were conducted. Fabric analysis revealed low dimensional stability and dye-dependent fibrillation, guiding ongoing optimization. First Fancy yarns with LFY and staple lyocell were developed for flat knitting. Test methods were defined, reference fabrics compiled and early collaboration with industrial partners ensured alignment with application-specific requirements. Initial woven fabric trials laid the groundwork for future scale-up.
WP4 – Develop and validate Lyocell Filament (LF) end user textile applications
WP4 concentrated on the initial design, requirement definition, and preparatory prototyping activities for high-performance sportswear, automotive interiors, and technical reinforcement textiles. Industrial partners initiated co-development of application-specific concepts and early prototypes, while LENZ supported the optimization and assessment of Lyocell Filament (LF) yarn properties against application-specific needs. An independent and standardized testing framework (Deliverable D4.1) was established, including consolidated testing standards, with preliminary evaluation activities and feasibility assessments providing feedback for subsequent material and design refinement. Compliance and benchmark requirements (Deliverable D4.2) were defined as a flexible, living framework aligned with current and emerging EU textile regulations. Overall, the work has laid a robust foundation for full-scale prototype development, validation, and performance assessment in the next project phase.
WP5 - Determine the framework conditions for sustainable, economic and safe upscaling of Lyocell Filament production in Europe
WP5 addressed technical, environmental, and sustainability aspects to support future scale-up. Industry expectations and consumer perspectives were mapped, and lifecycle assessment (LCA) studies were scoped, including system boundaries, goals, and data requirements. Early collaboration across partners established a structured framework for scaling LF production, ensuring economic viability, environmental sustainability, and market readiness for industrial-scale applications.
