Changes

Ozone gas is comprised of three oxygen atoms (03) and is a much more powerful oxidizing agent than chlorine. It is very effective at fading pre-dyed/pre-printed fabrics and garments, can be performed at lower temperatures than hydrogen peroxide, and uses no water at all. In addition, ozone is completely biodegradable, as it reverts rapidly back to oxygen (02), leaving no chemical residue. However, the ozone bleaching process still requires an alkali addition to swell the fibre and remove motes from cotton, and scouring and sequestering agents still need to be used.[2 ] Additionally, ozone is highly unstable and cannot be stored. It must therefore be generated on-site as needed, meaning that any manufacturing facility intending to use ozone as a bleaching agent must invest in ozone generating equipment.

Laccase is an enzyme that has proven effective at decolourizing or fading pre-dyed/pre-printed apparel products. Generally speaking, enzymes are considered low impact because they are biodegradable (no waste products) and typically work well at low temperatures, thereby minimizing energy consumption. A small amount of enzyme often saves significant amounts of water, energy and chemicals used in bleaching.[3 ] For example, Gentle Power Bleach™, a bleaching technology developed by Huntsman Textile Effects and DuPont, is an enzyme-based peroxide process that enables bleaching of textiles at 65°C using a neutral pH. The company claims that using Gentle Power Bleach™ lowers treatment and rinsing temperatures and requires fewer rinse baths, resulting in significant water and energy consumption savings and eliminating the need for caustic soda altogether.4