Dyeing of cotton fabric with azoic dye

Theory: azoic dye are not ready mode dyes like reactive dyes. The insoluble azoic colors are synthesized inside the fiber by coupling of two individual components neither of which is a dye itself. These two components are on aromatic diezoniem

solt and an aromatic hydroxyl compound. After diazotization the actual color is developed in the substrate. In application of azoic colors, the first step is selecting the west suitable diazo and coupling components combination of a particular purpose is to decide which of the napthols can be used in conjunction with the available diazo components to give the color closest to the chemical shade and depth.

Fabric type : Cotton
Dye type : Azoic
Color : Orange

Recipe:

1^st step

Naptholation:

napthol   = 2% (owf)

NaOH    = 3 g/l

NaCl      = 5 g/l

Wetting agent = 1 g/l

Sequestering agent = 1 g/l

Levelling agent = 1 g/l

Ph  = 10

Temp = 30°C

Time = 15 min

Sample weight =5 gm

2^nd step:

Base = 2% (owf)

CH₃COONa= 2 g/l

HCL    = 2 g/l

NaNO₂ = 2 g/l

Wetting agent = 0.5 g/l

Sequestering agent = 1 g/l

Levelling agent = 1 g/l

Temp = 5°C

Time = 15 min

 

Curve For Azoic dye

Friction of the chemical required:

Wetting agent:

 It accelerates the wettability of material in solution thus helps to easy penetration of chemicals into substrate. Usually it is used in scouring, bleaching & dyeing process. It is available in market in from of yellowish liquid.

Sequestering agent: 

it one kind of surfactants surface active agent act in solid liquid, solid gas or liquid gas interfaces and reduces the interfacial tension.

Recipe calculation:

Dye: 100 gm fabric for  2 gm naphthol

           1     gm        “     “    2/100 “

            5   gm        “   “       2×5 / 100 “ = 0.1 gm

Water: 200 gm [ m:L = 1:40]

NaOH  ,    1000 CC water, Carrier  required = 3 gm

                    1              “              “               “      =3 / 1000 “

                    200          “                “             “      = 3 × 200 / 1000    gm = 0.6g

Similarity,

NaCL = 1 gm

Wetting agent = 0.2 g/l

Sequestering agent = 0.2 g/l

Levelling agent = 0.2 gm

2^nd process:

Dye: 100 gm fabric for  2 gm base dye

           1     gm        “     “    2/100 “

            5   gm        “   “       2×5 / 100 “ = 0.1 gm

Water: 200 gm [ m:L = 1:40]

NaOH  ,    1000 CC water CH₃COONa  required = 2 gm

                    1              “              “               “      =2 / 1000 “

                    200          “                “             “      = 2 × 200 / 1000    gm = 0.4g

Similarity,

HCL = 0.4 gm

NaNO₂ = 0.4 gm

Wetting agent = 0.1 g/l

Sequestering agent = 0.2 g/l

Levelling agent = 0.2 gm

Conclusion: Azoic dye are commonly used for dyeing of cotton although other cellulose fibers, wool and even some synthetic fiber as well the main advantage of this dyes is that produce an economical way to abtain certain shade especially red with very good wash fastness.