Novozymes’ new technology offers cold bleaching to denim manufactures
Cold, gentle and rapid processing
“Our cold bleaching solution is effective at tap water temperature,” says Ole Bill Jørgensen, business development manager for Novozymes' Textile division. “Other bleaching technologies require the use of more energy or water, and in some cases more process steps, to achieve the same bleaching effect.”
The enzymatic bleaching solutions that are currently available are usually based on enzymes known as laccases. They alter the indigo through oxidation. Depending on oxygen from the water or from the air, this form of denim bleaching can take a long time, and the processing step can require repetition. The new cold bleaching solution is based on enzymes known as peroxidases, and this innovation is formulated to work without extra oxygen from either the air or water. This new peroxidase has a very rapid reaction speed - 90% of the reaction finishes within 10 minutes.
Fabrics are often colored using both indigo and sulphur dyes. The cold bleaching solution is very effective when used with indigo dyes. It does not bleach black or brown sulfur dyes, and only slightly alters the tone of blue sulfur dye. This means that different color tones can be achieved with the same fabric using different dye combinations. The shades of cold finished fabrics can be very different from those finished with traditional chemicals.
“Novozymes’ cold bleaching solution can achieve in-demand fashion looks,” says Ole Bill Jørgensen. “Denim processors can apply this technology to current trends and create diverse looks for brand owners very quickly. Even just one wash cycle using this technology can create a variety of different color tones. We believe the full fashion potential will be further explored when the technology becomes broadly available to the industry.”