**5.5 Finish of the denim fabric**

Finishing steps in denim fabric production are essential for the performance and appearance of the fabric. After weaving, fabric is mechanically and chemically treated to give it a soft hand feel, to correct the dimensional stability, to add a new shade or color on the original warp color or to add performance feature to the fabric (**Figure 3**).


In the framework (**Figure 3**), the fabric compositions are accumulated to three different groups for each rigid and comfort/stretch elasticity levels. The impacts coming from fiber compositions are constructed according to the weight of fibers used in each composition group and weight level. The following production stages, namely spinning, warping, sizing, unwarping, weaving, packaging, and quality control, are taken as fixed processes for all design variations and based on 1 meter of fabric production. The impacts originated from dyeing and finishing processes are allocated according to the yearly production of 1 meter of dyed warp yarn and finishing of 1 meter of raw fabric, respectively, for each dyeing and finishing recipe.

Warp dyeing method of a denim fabric is independent from the raw material or elasticity choices. **Figure 4** shows the difference in the selected environmental impacts based on different warp dyeing methods. Regular indigo dyeing has the highest impact compared to the other methods in four categories-global warming

**Figure 4.** *Effect of warp dyeing methodology.*

*Life-Cycle Assessment as a Next Level of Transparency in Denim Manufacturing DOI: http://dx.doi.org/10.5772/intechopen.110763*

potential, eutrophication potential, abiotic depletion and water use out of five. In terms of land use, the environmental impact of sulfur dyes is almost doubled compared to indigo dyeing.

**Figure 5** shows the difference in the selected environmental impacts based on different finishing processes of a denim fabric. Optic finish and i-core finish have the highest impact in all of the impact categories. Coating and overdyeing follow these finishes.

As may be seen from both **Figures 5** and **6**, percentages are used as a measure to compare the different methods, as the absolute values are in different scales for each impact category and for the relevant routes.

In the impact assessment for each indicator, the burden coming from each composition per different weights, warp dyeing methodologies and finishing processes is added on top of the impacts coming from the fixed processes. **Figure 6** is an example

**Figure 5.** *Effect of finishing processes for a denim fabric.*

#### **Figure 6.**

*An example of an impact calculation for rigid, mid-weight, indigo dyed, and coated denim fabric made with 100% cotton.*

#### **Figure 7.**

*An example of a route selection for rigid, mid-weight, indigo dyed, and coated denim fabric made with 100% cotton.*

of the global warming potential calculation of a rigid, mid-weight, indigo dyed, and coated 100% cotton denim.

A comparison model can be developed for distinctive denim fabric designs based on normalizing and scoring each step in the LCA. Particular routes in the framework can be selected and results can be compared to a defined standard denim (**Figure 7**).
