Finishing processes

Finishing is one of the manufacturing stages for textile products, used in particular to colour them and/or give them different properties. A finishing operation can be carried out on a fibre, a yarn, a fabric (woven, knitted or nonwoven), or on a finished product.

There is a wide variety of processes used during finishing. These processes can be grouped into three main categories, which are not systematically implemented and depend on the materials and desired objectives :

1. Pre-treatment, which consists of preparing the yarn or fabric for the following stages.

2. Dyeing, which is used to colour the yarn or fabric.

3. Finishes, which are used to modify the appearance, surface, feel or properties of the product. Embroidery, printing and flocking are also finishing processes, but will not be covered in this fact sheet.

Ces procédés ont un impact environnemental variable selon les techniques utilisées -consommation d'eau, produits chimiques, risques sanitaires - mais concentrent une part importante des impacts du secteur textile et chaussures.

Environmental issues of production

Textile finishing accounts for a significant share of the environmental impacts of the textile industry because it combines wet processes (baths and rinsing), thermal operations (heating, drying, etc.) and the use of numerous chemical substances.

Textile wet processing is mainly concentrated in Asia — China, Bangladesh, India and Vietnam — as well as in Turkey, where most dyeing and finishing sites worldwide are located. This concentration is not neutral: some of these areas are already experiencing high water stress, and regulatory frameworks on effluent treatment and chemical substances vary greatly from one country to another.
The impacts described below should therefore be read in light of this geographical heterogeneity, rather than as a uniform global average.

1. Durability

Some finishing processes, such as mercerisation or anti-shrink treatments, aim to improve the robustness of textile products and their durability over time. However, it is important to note that most other processes have an aesthetic purpose, modifying the feel or colour of the product in order to meet market expectations.

There can sometimes be trade-offs: for example, some anti-crease finishes based on cross-linking resins may slightly reduce the tensile or tear strength of the fabric, while pronounced sueding improves comfort to the touch but increases sensitivity to abrasion.

The challenge is therefore to find the right balance between mechanical performance, comfort, aesthetics and longevity suited to the intended use.

2. Recyclability

Chemical finishes can constitute a barrier to recycling at the end of products’ life. In particular :

• Coatings may damage recycling equipment, prevent garnetting and create impurities in recycled materials. The same applies to encapsulations. 7
• Oil-repellent, stain-resistant or water-repellent finishes can also make recycling more complex, particularly in connection with the use of PFAS associated with these processes, which durably contaminate recycling streams, prevent the purification of new fibres and pose major health risks for future users.

To find out more, consult our good design practice guides for recycling textiles and footwear !

Several labels and certifications apply to finishing processes; the following are eligible for Refashion’s “Environmental Labels” eco-modulation.

Eco-modulations: Refashion promotes product eco-design approaches through a system of premiums and penalties. Discover the criteria and procedures for declaring eco-modulations.

Find out more

Understanding your supply chain

As finishing stages are often outsourced, it can sometimes be difficult to identify the operators and suppliers in the supply chain. Access to information on the processes or products used can therefore be a challenge.

One of the first steps to prioritise in order to better understand the impacts of these stages in the product life cycle is therefore to work on their upstream traceability. This first step will make it possible to better diagnose and then mitigate the impacts of finishing processes.

Reducing the environmental impact of chemical inputs

Dyeing 8 9

Several action levers exist to reduce the environmental impact of dyeing processes. An in-depth study of these processes and an impact assessment are recommended.

These include :

• Natural dyeing: Natural dyeing is an ancestral and relatively artisanal practice. However, some dyers are developing processes to industrialise this practice.
• Dry dyeing: This covers processes that eliminate or drastically reduce the use of water baths. The two main industrial techniques are based on the use of supercritical CO₂ as a solvent, or on dope dyeing (integrating pigments into molten polymers before extrusion of synthetic fibres). Dyeing is possible on virgin fibres, but also on garnetted recycled fibres (after colour sorting and spectrometric analysis, precise dosing makes it possible to achieve the desired colour and thus also limit the use of chemical compounds).
• Digital dyeing: This is dyeing the fibre through to the core using a laser, which avoids the consumption of water and chemicals. In addition, ADEME recommends removing or limiting dyeing where possible (favouring the raw colours of recycled fibres, ecru for natural materials, etc.)

Focus on denim 10

New denim fading techniques are emerging and make it possible to avoid practices such as sandblasting, which are harmful to the environment (non-renewable material) and to workers (creation of silica dust that can cause silicosis).

These practices help reduce water and energy consumption :

• Laser fading engraves the surface of the fabric.
• Ozone fading exposes damp jeans to ozone to oxidise the fabric..