reactive & disperse dye
TRANSCRIPT
MD.MEHEDI HASAN RIMAN ID : 12132107012
Intake : 8th Section : 01
BUBTDepartment of Textile Engineering
Presentation on
Reactive Dye & Dispersedye
Reactive Dye and Disperse Dye
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Textile Auxilaries1 Salt- reduce negative charges on the fibers
2. Water - dyeing media
3. Soda Ash - excite the dye to link with the fibers with covalent bonding. Therefore, it enhances wet fastness
4. Fixing Agent - enhance wet fastness for heavy shade but usually reduce light fastness.
5. Levelling agent - for levelness dyeing
6. Retarding agent - for inhibiting the dye not attach to fibbers too fast
7. Acid - adjust the dyeing condition and make the fibbers to show negative charges
8. Water - dyeing media
Reactive Dyes
water-soluble compounds
give excellent wet-fastness
easy to hydrolyzed
Enough simple dyeing proses
Choice of more complete available color
Good color resilience
General Properties of Reactive dyes
Permanency of the color
Easy washing
Chemical Binding
Types of reactive dyes
Vinylsulphone Dye (VS)
Monochlorotriazine Dye (MCT)
Bi-functional Dye
Advantages of the Reactive Dyes
1. Hot reactive dyes
Reactive dyes which have low reactivity ( monochlorotriazin
faction )
Example of : Procion HE type ( ICI ) , Negative HE type
( Colorindo )
2. Cool reactive dyes
Reactive dyes which have high reactivity ( dichlorotriazin faction )
Example : Procion MX type ( ICI )
Based on its reactivity , reactive dye divided 2 faction :
Illustrating reaction which happened by at dyeing process between reactive dye with cellulose fiber
Side Reaction
•Hydrolysis of dichlorotriazine
1.Results in wasted dye
2.Economic and environmental concern•Typically fixation of around 60% is obtained
Dyeing Conditions
Time allowed for diffusion of dye into substrate‰ Concentration of dye in fiber is up to 500 times greater than in solutionAcidity difference creates ~25-fold excess cellulose anion
Leaving Groups
Variation of substituents = variations in fixation‰ “Cold” dyes = fixation temperature of 30-40°C‰ “Warm” dyes = fixation temperature of 50-80°C‰ “Hot” dyes = fixation temperature of >80°C
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REACTIVE DYES
This is an entirely class of dye introduced to the market in 1956.
They react chemically with the fiber being dyed & if correctly applied, cannot be removed by washing or boiling.
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REACTIVE DYES
The main feature of the dyestuff is its low affinity to cellulose; therefore large amounts of salt are required to force its deposition on he fabric.
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REACTIVE DYES
After this has been achieved, addition of alkali causes the deposited dyes to react with the fiber.
Only a successfully concluded reaction guarantees a fast dyeing.
Basically there are two types of reactive dyes: the cold dyeing & hot dyeing types.
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REACTIVE DYES - USE: Reactive dyes are used where
bright dyeing with high light & wash fastness is required.
Cold dyeing is used extensively in batik work.
Although some reactive dyestuffs have been specially modified to dye wool, their main usage is in dyeing cotton linen & viscose rayon.
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REACTIVE DYES Cold water fiber reactive dyes, suitable for dyeing on cotton, silk, jute, rayon & hessian.
Cannot be used on synthetics or fabric that has been coated with resin or drip-dry finish.
Yellow 2GLGolden Yellow 2RL
Orange 2R
ScarletRed BG (primary)Red 4B (bluish red)Red 8B (magenta)Rubinole 5BBrilliant Blue 2RBrilliant Blue BLViolet 2RTurquoise 2GNavy GRLBrown 2RBrilliant Green BLBlack B (blue base)Black 2B (green base)
DYES for SYINTHETIC FIBERS
Popular Dyes For Synthetic Fibers
Name of fibers Name of common dyes that are used
Polyester Disperse Dyes
Acetate (Cellulose acetate) Doesn't take dyes ordinarily. It requires cross dyeing.
Acrylic Disperse dyes
Mod acrylic Fiber Reactive Dyes
Modal Fiber Reactive Dyes
Nylon Cationic Dyes, Acid Dyes, Disperse Dyes
Orlon Disperse Dye
Rayon Acetate Rayon Dyes
Saron RIT Dyes
Spandex Disperse Dyes
Vinalon Doesn't take Dyes (in normal condition)
Vinyon Doesn't take Dyes (in normal condition)
Disperse Dyes DISPERSE DYES FOR DYEING IS DIVIDED BY 3 FACTION :1. Disperse dyes of the size molecule small Example : Dispersol B ( ICI )
2. Disperse dyes of the size molecule mediumExample : Dispersol C ( ICI )
3. Disperse dyes of the size molecule bigExample : Dispersol D ( ICI )
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Dye for Other Fibres:Disperse Dyes for Polyester, Acetate
Cationic Dyes for Acrylic
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Introduction to Coloration & Finishing
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Classification of dyesDye Class General description
Main application
Disperse Require skill in application (either by carrier or under high temperature); moderate price; complete color range; limited solubility in water (normally dispersed in water for application); good fastnessafter reduction clearing treatment; sublimation property.
Mostly used for polyester& acetate; can also be applied on nylon & Acrylic.
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DISPERSE DYES
The introduction of a new regenerated cellulose acetate fiber in 1920 led to the necessity to develop an entirely new range of dyes.
It was found that acetate (or Celanese) fiber had hardly any affinity for water-soluble dyes.
A new dyeing principle was introduced: dyeing with water dispersed coloured organic substances.
These finely coloured particles are applied in aqueous dispersion to the acetate material & actually dissolved in the fibres.
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DISPERSE DYES - USE:
Basically developed for dyeing of acetate fibres, Disperse dyes are also used for dyeing of polyamide (Nylon) & acrylic (Orlon & Acrylan) fibres.
With the addition of 'carriers' or swelling agents these dyes are also used in dyeing of Polyester (Terylene, Dacron, etc.)
Advantage and disanvantage:
1. Disperse dyes of the size molecule small
- Dyeing levelness very good
- Hot resilience low
- Temperature dyeing low ( economical energy )
- Usable for dyeing 130 0C with very by good level
2. Disperse dyes of the size molecule medium
- Dyeing levelness good
- Good color resilience
- Absorbtion dye into maximum fiber
- Not sensitive to temperature and time
- Accessible dye at characteristic temperature 130 C in a
short time
3. Disperse dye of the size molecule big
- Resilience color to temperature very good
- Sensitive to time and temperature
- Need to process reduction clearing ( RC )
Disperse Dyes for Polyester Dyeing Method
1. High temperature high pressure dyeing
dyeing at atmospheric pressure
Fixation 45 to 60 minutes at 120°C t0 130°C
2. Carrier dyeing
carried out under atmosphere pressure by an addition of carrier
Fixation 90-120 min at 100°C.
3. Thermosol dyeing
continuous dyeing method
fixation dry heating for 60-120 sec. at 180- 210°C (depending on
the form of the material and type of disperse dyes)
Dyeing of polyester/cotton blend
Three well known exhaust dyeing procedures :
(1) a conventional two bath procedure
(2) a reverse two bath procedure
(3) a one bath, multi step procedure
(1) The conventional two bath procedure
1. first dyed with a disperse dye at pH 5-7 at 120°-140° C to dye
the
polyester.
2. removed from this first dye bath and transferred to a second dye
bath containing a fiber reactive dye, electrolyte and alkali.
(2)The reverse two bath procedure
1.first dyeing the cotton with the fiber reactive dye
2. dyed the polyester with the disperse dye in separate dye baths.
(3) In the one bath multi-step procedure
1. a single dye bath is prepared and the cotton portion of the blend
is
dyed alkaline conditions low temperature the presence of
electrolyte.
2.The dye bath is then acidified to lower the pH and a disperse dye
is
added
the polyester portion of the blend is dyed at 120° C. to 130°
C.