Wool fabric production is crucial in driving innovation within the textile industry. Technological advances have enabled the processing and adaptation of wool fabrics for various applications [1] . As a result, wool fabrics can be utilized in both conventional and innovative textile designs. Due to their inherent elasticity, high thermal insulation, and superior moisture management, wool fabrics provide aesthetic appeal, comfort, and durability, making them indispensable in modern textile applications [2] .

Sustainability has become a primary focus in contemporary textile manufacturing, with objectives such as reducing carbon emissions, minimizing water consumption, and utilizing recyclable materials [3] [4] . The renewable nature and reusability of wool contribute significantly to waste reduction in the textile sector. Wool’s sustainability aspects are critical for minimizing environmental impact, optimizing resource efficiency, and extending product lifespan [5] . Additionally, wool fabrics align with circular economy principles by offering a recyclable and biodegradable material option [6] . Given their compostability and recyclability, wool-based textiles support “zero-waste” strategies [7] . Furthermore, within the slow fashion movement, the preference for durable, high-quality textiles has increased the demand for wool fabrics [8] .

Wool fabrics are frequently blended with elastane-based fibers to enhance their natural elasticity and mechanical performance [9] . Although wool inherently exhibits a certain degree of flexibility, various finishing treatments are required to enhance its elastic recovery and resistance to permanent deformation during wear.

Several finishing techniques are employed to enhance wool fabrics’ elasticity and mechanical properties. These include elastomeric coatings, resin treatments, and protein modifications, while mechanical approaches such as stretching, steaming, and heat-setting processes are also widely applied [10] . The finishing process plays a critical role in improving elasticity. In wool-Lycra fabrics, thermalization is applied to stabilize elastane fibers, whereas thermal treatment under controlled temperature and humidity conditions is used to modify the elasticity of natural wool fibers. However, these treatments exhibit distinct effects on fabric performance, durability, and comfort properties [11] .

This study investigates the comparative performance of wool-Lycra blended fabrics with different woven structures and wool fabrics subjected to natural finishing processes to enhance elasticity. Post-finishing, the fabrics were evaluated for key physical and mechanical properties, including tear strength, tensile strength, seam slippage, elongation and permanent elongation, abrasion resistance, Dimensional Change Against Steam Press A, Dimensional Change Against Steam Press B, and color fastness characteristics. The influence of these finishing treatments on fabric performance was systematically analyzed.

The tear strength of the fabrics obtained in this study was evaluated in both the warp and weft directions (See Figure 6 ), with the highest value associated with the W-T2 fabric. The fabrics with the highest tear strength have a 2/2 Twill weave structure. The 2/2 Twill weave structure is looser, which allows the yarns to slide during tear and better distribute the applied load. The yarns used in the 2/2 Twill weave structure are more twisted and thicker than those used in other weave structures, contributing to an increase in tear strength. After the finishing process, tear strength generally shows greater resistance in the warp direction. The thermofixation process has been particularly effective regarding tear strength in the Twill 2/1 and 2/2 fabrics. Following the finishing process, the 100% wool fabrics exhibited higher tear resistance than the Lycra-blended fabrics.

The tensile strength of the 2/1 and 2/2 Twill woven fabrics is higher compared to plain woven fabrics. Particularly in the 2/2 Twill weave structure, the tensile strength reached 27.1 kgf in the warp direction and 39.7 kgf in the weft direction. The high yarn strength (161 - 234 cm) and twist (750 - 900 T/m) in the 2/2 Twill woven fabrics contribute to the increased tensile strength of the fabric. The break strength of the 100% wool fabrics, which gained natural elasticity through the influence of temperature and chemicals, increased in relation to the dimensional stability of the wool fabrics. Fabrics, particularly those with a 2/2 Twill weave structure, show high tensile strength values after the finishing process.

In Figure 7 , the fabrics with the W-T2 weave structure (20.4 mm) and the W-T1 weave structure (18.7 mm) exhibit the highest seam slippage. This situation is generally associated with a looser knit construction and lower yarn twist ratio. The W/L-P knit fabric shows the lowest seam slippage in the weft direction (12.2 mm). The tight weave structure and high yarn twist ratio prevent the yarns from slipping along the seam. This characteristic provides the fabric structure with more durable and long-lasting properties. The lowest warp strength may result in higher seam slippage after thermofixation, while Lycra stabilization may increase seam slippage.

The W/L-T2 fabric (16.7 mm) and W-P fabric (15.4 mm), along with the W/L-T1 fabric (14.4 mm), exhibit noticeable seam slippage. The connection points in the fabric’s knit structure are fewer, so under excessive load and tension, deformation may occur compared to the 2/2 Twill structure fabrics. The 2/2 Twill structure has reduced seam slippage; however, due to Lycra, seam slippage may still occur in the weft direction after thermofixation. The W/L-P fabric (12.2 mm) has the lowest seam slippage in the weft direction. The plain, tightly knitted structure and high yarn twist ratio make seam slippage more difficult. It exhibits the highest seam strength and is minimally affected by thermofixation, maintaining its stability.

The elongation percentage characteristics of the produced fabrics, as shown in Figure 8 , demonstrate that Lycra-based fabrics generally exhibit higher elasticity. These fabrics have an elongation rate of 23% to 23.4%, with permanent elongation rates between 1% and 1.3%, indicating that most of the high elasticity is recoverable. For 100% wool fabrics, the elongation rate ranges from 18.6% to 20%, with a permanent elongation rate of 1%. In this case, wool fabrics have lower elasticity. However, with the Twill knitting structure, elasticity is increased, and the permanent elongation rate reaches 21.7% with a 0.7% permanent elongation. Thus, a balance has been achieved in wool fabrics, allowing for permanent elongation without Lycra. After the finishing processes, the Lycra-blended fabrics exhibited a reduction in permanent elongation and an improvement in recovery. The best balance in permanent elongation was achieved in the Wool-Lycra Twill 2/2 (W/L-T2) fabric.

As shown in Figure 9 , the abrasion cycle properties exhibited higher durability in the Lycra-based fabrics. When the knitted structures underwent finishing processes and were combined with the Twill weave structure, they became both more flexible and more resistant to abrasion. According to the finishing process results, Twill woven fabrics exhibited higher abrasion resistance compared to plain woven fabrics. While Lycra-containing wool fabrics enhanced their elasticity, they showed a reduction in abrasion resistance. The fabric with the best abrasion resistance was the Wool-Twill 1/1 (W-T1) fabric.

Figure 10 shows that the fabrics L-P, W/L-T1, and W/L-T2 exhibited greater dimensional changes when pressed with steam. Generally, these fabrics demonstrated higher flexibility and dimensional changes, but they maintained dimensional stability, with W/L-P showing the most significant changes. Although the Lycra structure provides elasticity to the fabrics, it also limits their dimensional changes. Wool fabrics without Lycra, such as W/P, W-T1, and W-T2, showed less dimensional change. These fabrics, particularly those with the Twill knit structure, exhibited lower dimensional changes during the steam press process. Wool Twill fabrics, such as W-T2, demonstrated highly stable structures with dimensional change rates of 0.5%. Overall, the finishing process improved dimensional stability across all fabrics, with Lycra-containing fabrics showing higher dimensional changes. These alterations promote fiber reorientation, reduce residual stresses, and stabilize the yarns, particularly in Lycra-blended fabrics. These treatments cause a permanent dimensional set, which is a key feature for the performance of tailored garments, where retaining shape and structure is crucial. Although minimal recoverable shrinkage may be observed after further laundering or re-pressing, the majority of the dimensional changes are irreversible, ensuring that the garments maintain their intended fit and structure over time. The best stability was observed in the Wool-Twill 2/2 (W-T2) fabric. The Twill weave structure, combined with finishing processes, contributed to better dimensional stability.

This study analyzed the mechanical and physical properties of different fabric types after the finishing process. Overall:

In conclusion, the Wool-Twill 2/2 (W-T2) fabric demonstrated the best performance in terms of breaking and tearing strength, abrasion resistance, seam slippage, and dimensional stability. Wool/Lycra fabrics stood out for their elastic properties. Finishing treatments, especially on twill structures, positively affected the overall fabric properties.