What is the real "waterless dyeing"?

2021/04/20

Guide:Anhydrous dyeing refers to a dyeing method that does not use water as a carrier. Anhydrous and less water are two different concepts.

The true water-free dyeing technology now has two kinds of supercritical fluid water-free dyeing and solvent dyeing.



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What is the real "waterless dyeing"?

 

The following will focus on the supercritical fluid waterless dyeing technology:

 

#1. Supercritical fluid anhydrous dyeing

 

In the supercritical state, the supercritical fluid is in a semi-liquid gas state, which makes the supercritical fluid have both the dissolving ability of liquid and the diffusing ability of gas. In the supercritical fluid anhydrous dyeing process, the supercritical fluid can not only dissolve the dye, but also can easily penetrate into the interior of the textile, completing the process of dye dissolution→adsorption→dyeing.

 

#2. The invention of supercritical CO2 dyeing technology

 

The supercritical CO2 dyeing technology was invented in 1989 by E. Schollmeyer, Northwest Textile Research Center, Germany. This technology uses supercritical CO2 as the dyeing medium to dissolve the dye into the fiber pores, so that the dye can be dyed on the fabric quickly and evenly. After the dyeing is finished, the CO2 can be fully separated from the dye, without the need for cleaning, drying and other operations. Unused dyes can be recycled.

 

#3.The principle of supercritical CO2 dyeing technology

 

The CO2 is heated and pressurized to a supercritical fluid state that is neither a gas nor a liquid, and is pressed by a circulating pump to continuously circulate between the dye tank and the dye tank. The supercritical CO2 fluid dissolves the dye while dyeing the fabric. The dyeing conditions are 20~30MPa, 80~160℃, and the dyeing time is about 1h. After dyeing, the remaining dye and CO2 can be recovered and recycled. 

 

 

#4.  The development of supercritical fluid dyeing

 

In 1991, Jasper and Germany Northwest Textile Research Center (DTNW) developed the first semi-industrial dyeing machine with a volume of 67L. (see picture 1)

 

 

 

In 1995, the German Uhde (Wood) Company and the German Northwest Textile Center (DTNW) cooperated to develop an equipment with a dye liquor circulation system with a dyeing tank capacity of 30L. This equipment was exhibited at the Milan Textile Machinery Exhibition in Italy in 1995 and at the International Textile Machinery Exhibition in Osaka, Japan in 1996, and received widespread attention. Later, Wood Company continued to improve the equipment and introduced the improved equipment in 1999. (See Figure 2)

 

 

 

In 1997, the European Union funded a three-year supercritical fluid dyeing research project SUPERCOLOR. The main research is undertaken by the French Textile Research Institute, and the equipment is manufactured by the Swiss company Chematur and named "Rotacolor". The volume of the equipment is 7L, the pressure is 400bar, and the heating temperature is 150℃. (See Figure 3)

 

 

 

  • In 2005, the Delft University of Technology in the Netherlands developed a 40L supercritical fluid beam dyeing machine and achieved success. (See Figure 4)

 

 

  • In 2008, the Dutch company Dyecoo carried out the commercial operation of supercritical CO2 dyeing equipment for the first time, and in 2010 provided the Thai Yeh Group with a beam dyeing equipment system with a capacity of 100-200 pounds, and it can be commercialized on a certain scale. Production and mass market launch in 2011.

 

 

(Picture: Dyecoo's waterless dyeing machine)

 

  • The equipment jointly developed by Dyecoo and Yeh Group will be the world's first real supercritical dyeing production equipment.

 

 

In 2012, Adidas cooperated with Thailand's YE Group and launched the first water-free dyed T-shirt named: DRYDYE. The following are the promotional images and videos of Adi at that time (In the summer of 2012, Adi sold the first batch of 50,000 T-shirts without water printing):

 

 

 

In 2012, Nike invested in the Dutch company Dyecoo and used it for the development of water-free dyed sweatshirts and other products. Name the anhydrous dye: ColorDry.

 

 

 

 

In the same year, Huntsman and the Dutch company DyeCoo jointly developed the CO2 supercritical dyeing technology.

 

 

 

In 2013, Nike’s main partner, Far East New Century Company of Taiwan, also invested and purchased equipment from Dyecoo in the Netherlands and carried out the research and development and production of Nike’s ColorDry fabric.

 

 

 

 

#5. Prospects of waterless dyeing technology

 

Dyecoo's waterless dyeing is now limited to polyester fibers. The pretreatment of various fibers, the dyeing of cellulose fibers, and the dyeing of other fibers (nylon, acrylic, etc.) are still worth looking forward to!

 



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