Dyes and color index( CI) numbers

The color index is produced jointly by SDC (Society of Dyers and Colourists) in the UK, and the AATCC (American Association of Textile Chemists and Colorists) in the USA. The index is split into two parts: one part gives the commercial names for the individual dyes; the other part of the index gives the color index number, and lists the commercial names for the dyes using that number. 

Color index number

Every dye is given a color index number based on its chemical type. The same number is given to the dyes with the same chemical structure. For example, Resolin Red FB and Dispersol Red B2B, both have the color index number “CI Disperse Red 60." The index number is divided into four sections: 

1) CI stand for color index and is displayed in every color index number 2) The next section is the dye type, e.g., Disperse, Acid, etc. 

3) The third section is the color, according to a defined list of color names, e.g., Red Yellow, Orange 

4) The last number is increased every time a new dye is added to the index; in the example above, “CI Disperse Red 60" is the 60th red disperse dye to be added to the index. 

As an extensive international compilation of the structure and properties of dyes and pigments, as well as a system of numbering these materials, the Colour Index is a potentially valuable tool for all users of colorants.

CAS numbers for chemicals and chemical compounds

CAS Registry Numbers are an important tool for substance searching. These are unique identifiers assigned by the Chemical Abstracts Service (CAS) to specific substances identified by them in the chemical literature.

Registry Numbers save you from having to think of all the different synonyms, trade names, or possible systematic names when you are doing a compound search by linking them all into a single search term.

For example, there are over 20 synonyms for formaldehyde, e.g., methanal, formalin, methyl aldehyde. The CAS Registry Number for it, 50-00-0, is specific to all those names for the same compound.
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Textile Jobs

Denim pollution

People around the world share one fashion love “blue jeans.” Denim may be stylish, but also has many unexpected downsides pollutants.Two techniques commonly used that became the hallmarks of blue jeans are the well known indigo color and the worn out look that make the statement in a pair of jeans. Unfortunately, the chemicals involved in their processes contribute to pollution. Today the indigo dye is produced from coal or oil (a process that can release toxic byproducts like cyanide and formaldehyde) while stonewash uses volcanic rocks or pumice stones which releases pumice dust that endanger worker’s health and produces gritty sediment waste.

http://cnn.com/video/?/video/world/2010/04/26/chang.blue.jeans.cnn

Dyeing Cationic Dyeable Polyester (CDP) with Cationic Dyes By Michael Hilton

This article is contributed by Michael Hilton

Cationic Dyeable Polyester is a special Polyester fiber which has undergone a change during polymerization. They were built of molecules of 5 - sulphophthalic acid, to generate anionic sites that the fibers of normal PET not have. Having anionic groups it can also be dyed with cationic dyes with results of high brilliance. However, these fibers can be dyed with disperse dyes. Compared to ionic dyes, disperse dyes have smaller molecular extinction coefficients and lower build-up property, so these dyes cannot give bright and deep colors. This type of fibers were born also to lower the Tg (glass transition temperature) of the polymer, 10 ° C lower than normal Polyester fibers, so to obtain a more segmental mobility and open polymer structure. Resulting in increased rate of diffusion of the dye in the fiber at a lower temperature. Tg Range (70 – 85°C). This modified polymer is also more easily hydrolised and more sensitive to heat setting before dyeing at a maximum temperature of 180°C.

Example 

scouring and dyeing exhausted process in Overflow – Jet Machine (Liquor ratio - 1:10 – 1:20) :

Scouring:

Continuous washing cold for 10 min 

drain well (for water soluble oils)

Fill with water 30 ° - 35°C

0,5 g/l Antifoam (preferably non-silicone) alone

1 g/l Detergent non – ionic

0,5 g/l Caustic Soda 36° Bè

Raise to 80°C quickly and hold for 20 – 25 min

Drain well 

washing cold for 10 min 

and after starting in dyeing

Dyeing with Cationic dyes

Follow the Graph below :

The dyebath is set at 60°C - introduce order

0,5 g/l Antifoam (alone)

6 g/l Sodium sulphate (only dyeing at 120°C) (1)

1 g/l Dispersant non-ionic

X g/l Acetic Acid pH = 4,5

X % Levelling – Carrier anionic (only dyeing at 98°C)

X% Cationic dyes (dissolved at 60°C with 1 g / l of acetic acid) - (introduce preferably dosed curve progressive Sen +)

Then raise to 70°C - after to 85°C at 0,5°C / min (while the fiber is softening) and hold for 10 min, after raise to 120° (or 98°C) at 0,6°C / min – hold for 30 – 60 min (depends on the depth of the color) 

then cool to 70°C at 0,5°C / min and check the color.

Please note that sodium sulphate (Na +), being very stable at high temperatures, is the protector of te anionic sites sensitive to the acid at 120 °C.

After dyeing, the dyed samples were rinsed and washed with 2 g/l of non-ionic detergent at 60 – 70°C.

Light fastness: moderate to good

Washfastness: good to excellent

Rubbingfastness: good

Excellent resistance to sublimation on wet

No fouling of lycra mixed