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Tuesday, May 28, 2024

BEZAKTIV ONE: Dyes for Water- and Energy-Saving Dyeing Processes

BEZAKTIV ONE is a new range of reactive dyes by CHT Switzerland. BEZAKTIV ONE covers a wide spectrum of dyes exceptionally rich in color. This range enables cost-effective dyeing processes with lower dye amounts and reduced salt consumption for exhaust processes.

The excellent wash-off performance of BEZAKTIV ONE also supports economical and ecological dyeing. Excellent multiple-washing fastness is another benefit, which is why we have coined these dyes “The New WOW of Dyeing.”

Textiles are produced in large quantities around the world, and the industrial processes for textile finishing and dyeing are largely the same everywhere. Textiles made of cotton and other cellulosic fibers are very popular because these fibers and their blends can be used to produce a wide variety of products with high wear comfort and good stability. The popularity of cotton is likely to remain high in the future, with global demand expected to remain constant or even rise. Agricultural land is limited, and cotton production necessitates high water consumption. For these reasons, the issues of textile recycling and durability are likely to increase in significance in the future. Today, cellulosic fibers are usually dyed with reactive dyes. That’s because these dyes are commercially available in a variety of different colors and result in dyed products with a high washing-fastness level. Reactive dyeing of cellulosic fibers still takes place via water-based processes. A trend is emerging toward energy- and water-saving processes, such as cold pad batch (CPB) processes or exhaust processes with very low liquor ratios. Minimizing the number of rinsing baths and generally reducing the temperatures of the dyeing and rinsing baths also contribute to further conservation of water and energy in dyeing processes.

The properties of reactive dyes are quite significant for their success in such processes. Requirements for the dyes include a sufficiently high fixing speed, very good wash-off properties, and excellent solubilities. In addition, the dyes must be suitable for all dyeing processes and must combine very well with each other. Furthermore, reactive dyes are expected to flawlessly achieve consistent color results, and with high reproducibility and fastness. Efficient use for dark shades requires good color build-up. To ensure long-lasting color intensity and
brilliance of dyed textiles, reactive dyes must demonstrate a high degree of stability even after repeated washing with detergents that contain bleach. The constituents of the BEZAKTIV ONE line exhibit these properties: They combine well with each other, are suitable for reduced dyeing and soaping process time and temperatures demonstrate good multiple-washing fastness, and are even free of harmful substances.

Dyes for light to medium shades
The new line contains a variety of brilliant reactive dyes that are perfect for light to medium shades, cover a large color space, and lead to excellent fastness properties. Several deep elements with good color build-up are also available for darker shades (Fig. 1).

The recommended temperature for dyeing, washing, and soaping BEZAKTIV ONE dyes is 60°C. Temperature reduction to 40°C is permissible with selected elements. Conventional reactive dyes require rinsing at 70 – 80°C and soaping at boiling temperatures. The exhaust process is thus substantially shorter with BEZAKTIV ONE than with conventional reactive dyes. Furthermore, the number of rinsing baths is reduced. This advantage improves the textile dyer’s productivity by curtailing process time. Most elements of the new BEZAKTIV ONE range have a significantly more intense color than conventional bifunctional reactive dyes. As a result, the corresponding dye recipes often contain a lower
proportion of dye, thus enabling lower electrolyte concentrations in the exhaust processes. The eliminated salt and the resulting overall lower salt concentrations in the dye – and rinsing baths yield considerable cost savings in terms of the dye recipe. On top of this, the wash-off behavior of the non-fixed components after dyeing is significantly improved. The advantages of the BEZAKTIV ONE process become particularly clear with medium to dark shades. In this color range, a relatively high proportion of non-fixed dye needs to be washed off in conventional processes. Combining a high degree of fixation with excellent wash-off properties means that the rinsing and soaping process can be highly efficient. The addition of auxiliaries in the soaping bath further amplifies the benefits, resulting in a washing process with low water and energy consumption that leads to a textile with excellent wet fastness. For CPB dyeing as well, the relatively high fixing speed enables shorter dwell times. Plus, the good wash-off properties create savings in the continuous washing processes for dark shades and black dyes.

Dyeing dark colors
For the darker color spectrum, the focus is on good color build-up: BEZAKTIV Orange ONE and BEZAKTIV Deep Red ONE are strong elements with good light fastness. They combine very well with BEZAKTIV Dark Blue ONE and result in outstanding light fastness. For navy or black shades, BEZAKTIV Deep Navy ONE is available as an intense navy blue with excellent wash-off-capacity, multiple-washing fastness, and chlorine fastness. Dark shades, such as a deep navy (Fig. 3), can be achieved with low volumes of BEZAKTIV ONE dyes. Plus, the wash-off capacity is significantly better with this dye than with conventional bifunctional reactive dyes.

The BEZAKTIV ONE line has two new deep black shades for dyeing in the black range. BEZAKTIV Black ONE does not contain CI Reactive Black 5. It is suitable for deep-black dye results with both exceptional wash-off properties as well as good multiple-washing fastness (ISO 105-C09). BEZAKTIV Deep Black ONE is an intense black shade with excellent wash-off-capacity and very effective color build-up.

All elements of the BEZAKTIV ONE range are free of p-Chloroaniline (detection limit 5 ppm), exhibit good multiple-washing fastness, and meet the highest standards for ecology and sustainability.

Thanks to their outstanding technical properties, the new BEZAKTIV ONE dyes make energy- and cost-saving dyeing processes possible. This is how they fulfill all pertinent eco-label and certification requirements. The CHT Textile Dyes App (available for free for iOS and Android) contains all dye profiles as well as extensive data on the individual dyes. With the new BEZAKTIV Soaping Advisor (a program within the CHT Textile Dyes App), it’s incredibly easy to optimize the dyeing processes of a specific recipe in terms of time, energy, and water consumption.
by:
RALPH STEFFENS Dr. Product Manager / Research & Development CHT SWITZERLAND AGralph.steffens@cht.com
GUNTER WALCHER Dr. Product Manager / Research & Development CHT SWITZERLAND AGgunter.walcher@cht.com

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