NATIONAL TEXTILE UNIVERSITY
FACULTY OF ENGINEERING & TECHNOLOGY
Name: Shahan Akhtar
Reg# 20-NTU-MSTT-6077
Semester: 01
TT-5063
Advance Textile Proessing
Fall 2020
Lab no. 1
Title:
Dyeing of fabric with direct dye by using thermosole dyeing machine
Introduction:
Direct Dye is a class of dyestuffs that applied directly to the substrate in a neutral or alkaline
bath. They produce full shades on cotton and linen without mordanting and can also be applied
to rayon, silk, and wool. Direct dyes give bright shades but exhibit poor wash fastness. Various
after treatments are used to improve the wash fastness of direct dyes, and such dyes are referred
to as “after treated direct colors.” Direct Dyes are molecules that adhere to the fabric molecules
without help from other chemicals.
Experimental procedure:
The dyeing of a textile fabric is carried out in a solution, generally aqueous, known as the dye
liquor or dye bath. For true dyeing to have taken place, coloration of fabric and absorption are
important determinants.
1. Set the dye bath with substrate at room temperature.
2. Add dye solution with other auxiliaries (salt) and raise the temperature to 90℃
3. Run the dye bath for 30-50 min at 90-95℃ to complete the cycle.
4. Cool down the bath temperature to 60-70℃
5. Drop the bath and rinse.
The machine used for this purpose is pad thermal dye machine.
1. Take fresh water = 300ml in a beaker.
2. Take sodium chloride (Nacl) = 18g/300ml (std. 60g/l)
Sodium chloride dissolved in fresh water (300ml).
Color Shade 2%
3. Take dye with respect to liquor ratio (mean water 300ml).Dye = 6g
(shade 2% and water 300ml =.02*300= 6) 6g dye is dissolved in sodium chloride mix water.
4. Load these dye mixers to Pad-thermosol dyeing machine (TC-M-31).
5. A bleached piece of fabric passed through the roller of Pad-thermosol dyeing machine (TC-M-31) at
temperature 150C, fabric piece taken 2 minutes for completion of work. Now the fabric is dyed.
For dye fixation:
6. Take fresh water another beaker = 200ml
7. Take Soda ash = 4g/200ml and dissolved in water. (std. 20g/l)
Add dyed fabric into soda ash solution.
8. Now, passed this fabric through pad machine roller for dye fixation at 158C.
For softener:
Take fresh water = 200ml
9. Take softener = 10g/200ml and dissolved in water (std. 50g/l)
Dissolved the dyed fabric into softener water.
10. At last, passed this fabric through pad machine for drying at 120C for 2 mins.
Observations:
Fabric hand feel is smooth and good
Color shade is ok.
Lab No. 02
Reactive dyeing
Objective: In this lab, learn about the procedure and solution of reactive dyeing and checking the effect of softener on the
shade of fabric.
Experimental Procedure:
1-Take fresh water in a beaker = 200ml
2- Taken these chemicals of given ratio and dissolve it into water (200ml).
Water = 200ml
Nacl= 12g/200ml std. 60g/l
Na2Co3= 6g/200ml std.30g/l
Urea= 2g/200ml std.10g/l (maintain the moisture of dye)
Ant migrating agent = 2g/200ml std.10g/l
Wetting agent = 0.4g/200ml std.2g/l
Squatting agent= 0.6g/200ml std.3g/l
Color Shade 2%
3. Take dye with respect to liquor ratio
Dye = 4g (shade 2% and water 300ml =.02*200= 6) dye is also dissolved in above chemical mix water.
4. Load these dye mixers to Pad-thermosol dyeing machine (TC-M-31).
5. A bleached piece 0f fabric passed through the roller of Pad-thermosol dyeing machine (TC-M-31) at temperature
150C, fabric piece taken 2 minutes for completion of work. Now the fabric is died.
For dye fixation:
6. Take fresh water another beaker = 200ml
7. Take Soda ash = 4g/200ml and dissolved in water. (std. 20g/l)
Add dyed fabric into soda ash solution.
8. Now, passed this fabric through pad machine roller for dye fixation at 158C.
For softener:
Take fresh water = 200ml
9. Take softener = 10g/200ml and dissolved in water (std. 50g/l)
Dissolved the dyed fabric into softener water.
10. At last, passed this fabric through pad machine for drying at 120C for 2 mins.
Observations:
Fabric hand feel is good Color shade is ok. In both cases (with & with out) application of softener
Lab no. 3
Title:
Dyeing of a fabric by using vat dyes.
Objective:
To dye a fabric using vat dye
To apply resin & softener on dyed piece of that fabric.
Introduction:
A dye is a colored compound, normally used in solution, It is defined as the compound which
containing chromophore and auxochrome groups called dye. Chromophore group is responsible
for dye color due to their saturation. Auxochrome group is responsible for dye fiber reaction. Vat
dyes are made from indigo, anthraquinone and carbazole. They are successfully used on cotton,
linen, rayon, wool, silk, and sometimes nylon. Vat dyes are also used in the continuous piece of
dyeing process sometimes called the pigment application process. The dyeings produced in this
way have high wash and light fastness.
The word vat means vessel. They are water insoluble but become soluble from by vatting
process. The process of converting insoluble vat dye by strong reducing agent and then
oxidizing again is called vatting process.
Experimental procedure:
The step in which the reduction of the dyestuff into its leuco-form takes place is called
vatting. It is the process of converting insoluble dye to soluble vat dye. they are reduced
to soluble leuco compound.
A strong reducing agent Na2S2O4.2H2O is used for vatting.
Absorption of leuco compound by the cotton during dyeing. The vatted dye (leuco form)
is substantive to the cellulose material.
Dyeing is carried out at lower temperature by padding then steam is provided to it for
dye penetration.
To achieve adequate exhaustion an electrolyte is added to the dye liquor & temperature
may be increase from 20-60 C & agitated for 15 min in an opened container for oxidation
process & add hydrogen peroxide and acetic acid.
Then wash with the cold water & the dry it.
After this process, three fabric pieces were dyed, one simple by oxidation process,
2nd by applying resin and 3rd by applying softeners.
Recipe:
Water = 500ml
Na2S2O4 = 5g
Dye = 10g
Steam time = 4 min
Temp = 102 C
NaOH = 5g/l
For oxidation:
Water = 2.5l
H2O2 =10ml
Acetic acid = 2.5 ml
Now put steam fabrics pieces into above solution and heated it at 60 c for 15 mints.
Wash these samples in fresh water then dry it. Vat dye is completed.
For softener:
Take water = 500ml
Take softener (Ariston 66) = 12.5g/500ml and dissolved in water.
Put one piece of fabric in softener solution.
For resin:
Take water = 500ml
Resin (fixapret CPF) = 25 g (std 50g/l)
Condensol-FM (for catalyst) = 1.5 g (std 3g/l)
Add these salts into water and put 2nd piece of fabric in that solution.
First dry at 120c for 1 min and then curing 150 c for 3 mints in a pad machine of two samples (softener and resin).
Results:
After applying resins and softner and simple dyed fabric, the fabric was checked under shade
change instrument & there we saw that the fabric that was just simply dyed have more intense
shade than that of resins and softner.
Lab no. 4
Title:
Dyeing of polyester fabric using non-ionic dye (disperse dye)
Objective:
To learn about non-ionic dye & its process on fabric.
Introduction:
Dyes are colored, unsaturated organic chemical compounds capable of giving color to a substrate (a
textile), i.e., coloring or dyeing it. The term “disperse dye” have been applied to the organic
coloring substances which are free from ionizing groups, are of low water solubility and are
suitable for dyeing hydrophobic fibers. Disperse dyes have substantivity for one or more
hydrophobic fibers e.g. cellulose acetate, nylon, polyester, acrylic and other synthetic fibers. The
negative charge on the surface of hydrophobic fibers like polyester cannot be reduced by any
means, so non-ionic dyes like disperse dyes are used which are not influenced by that surface
charge.
Experimental Procedure:
Disperse dyes are not soluble in water. Dispersing agents are used to make them soluble. It
captures the dye molecules from surroundings and disperse it into smaller molecules.
We use two methods for dyeing the polyester fabric:
1. High temperature dyeing methods.
2. By using Carries.
By using high temperature method:
At first a paste of dye and dispersing agent is prepared, and water is added to it.
PH is controlled by adding acetic acid.
This condition is kept for 15 minutes at temperature 60°C.
Then the dye bath temperature is raised to 130°C and this temperature is maintained for 1
hour. Within this time, dye is diffused in dye bath, adsorbed by the fiber, and thus
required shade is obtained.
The dye bath is cooled as early as possible after dyeing at 60°C.
The fabric is hot rinsed and reduction cleaning is done if required.
Then the fabric is finally rinsed and dried.
By using carriers method:
Carries are used to swell the fibers to make them dyeable, but they are non-friendly to
environment.
At first, a paste of dye and dispersing agent is prepared and then water is added to it.
Dye bath is kept at 60°C temperature and all the chemicals along with the material are
added to it. Then the bath is kept for 15 min without raising the temperature.
pH of bath is controlled by acetic acid at 4-5.5.
Now temperature of dye bath is raised to 90°C and at that temperature the bath is kept for
60 min.
Then temperature is lowered to 60°C and resist and reduction cleaning is done if
required. Reduction cleaning is done only to improve the wash fastness.
Material is again rinsed well after reduction cleaning and then dried.
Recipe:
Dye, dispersing agent, acetic acid, carriers.
Results:
Using the first method, the dye was not uniformly distributed on fabric surface. On contrast to 1 st
method, the carriers used for dyeing gives better results was evenly distributed. Levelled dye was
seen by using 2nd method
Lab no.5
Title:
Fabric Color Matching Process with Spectrophotometer.
Objective:
To study about the procedure of fabric shade Matching Process with Spectrophotometer.
Abstract:
A spectrophotometer is a special machine that measures the light intensities as a function of
wavelength. In this lab, a Data color 850 is used to analyze the color of a sample. It can quantify
the difference between an achieved color and its original standard. These differences are called
Delta E (error) Values. The delta acceptance levels are 0.5.
Introduction:
A spectrophotometer is a physical tool that is eminently suited to measure the most important
variable of all, the shade and strength of the dyestuffs themselves, whether they be in solution or
on the fiber. Spectrophotometer used by dyeing factory and colorant manufacturers all over the
world. Normally lab managers analyze the color of the swatch with the help of a
spectrophotometer.
Experimental Procedure:
Flow Chart of Color Matching Process with Spectrophotometer:
Calibration the data color 850 instrument.
Click the Calibrate button on the button bar, or Instrument Menu,
Calibrate.
Click Calibrate. The Prepare for Calibration dialog box displays.
Place the black trap over the measurement port and click the Ready
button.
Placed a standard fabric piece in front of scanning light and scan it.
Placed the given fabric piece in front of scanning light and scan it.
Use DL⁕, Da⁕, Db⁕ to match
Ok
Finished
Observations and Calculations:
CMC DE = 0.02 Pass
a = +ve Red
a = -ve Green
b = +ve Yellow
b = -ve Blue
Conclusion:
The Data color 850 spectrophotometer is color measuring instrument device for measuring,
specifying and evaluating color in both laboratory and production settings, especially where
precise digital color communication is required.
