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CHROMA INTERNATIONAL |
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Parkosol dyes are stable water soluble leuco esters
of vat dyes. They are generally applied in water soluble state and
subsequently converted to parent dyestuffs by oxidation in presence of
acids. The use of these dyestuffs gives brightness and fastness of vat
dyestuffs. |
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These can be employed for dyeing pale shades of
polyester cellulosics blends with excellent fastness by a one bath
technique. By printing generally these applied alongside Rapidfast dyes
to extend their shade range. |
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| DYEING |
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Jigger Dyeing : |
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The requisite quantity of solution added to
the dyebath at 50°C with 8-12 gms/l of calcined Glauber's salt.
Dyeing carried out for 30-45 minutes in a cooling bath. The
goods are squeezed and developed with 20-35 ml/l Sulphuric acid
(168°Tw) at 55-70°C in single passage. The goods are then
washed immediately in another jigger. The development &
soaping can be carried out simultanously in a countinuous soaper. Soaping should be carried out at boil with 2
gms/l soap.
The development should be for about 6-10 seconds. |
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Padding method : |
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Dyestuff is dissolved in
soft water and added to the padding liquor with 8 gms/l of
Sodium Nitrite. goods are padded and developed as per jigger
method. The temperature of padding liquor should be about
65-70°C. Generally the affinity of Parkosols are low, however,
with large padding troughs 5-10% stronger feeding liquor may be
necessary. With the dyestuff of high affinity such as,
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Green IB |
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Golden Yellow IRK, IGK |
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Blue 04B |
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it is advisable that feeding liquor must be
20-30% stronger, or the temperature of padding liquor should be
around 80°C. |
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The illustrations in
this shade card are on mercerised cotton poplin and have been
dyed by padding method at 100% expression and developed in
jigger. |
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| PRINTING |
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Generally Nitrite process is employed by
screen printers. The dyestuff is printed with Sodium Nitrite and
developed in acid bath. |
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Steaming is generally necessary, however,
short steaming in general improves the colour yield with most of
the dyestuffs. |
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The printed material is developed after
drying by about 2-4 seconds followed by air passage of 10-20
seconds. The material is throughly rinsed soaped at boil. |
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| NOTE : |
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1. |
Development should be carried out at 70-80°C
for Pink IR, Scarlet IB. Addition of 25 gms/l of Glauber's salt
minimises the tendency to strain unprinted protion of fabric.
Other dyestuffs can be developed at 60-70°C. |
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2. |
Golden Yellow IGK should be soaped at 60°C. |
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3. |
The printed goods should not be exposed to
sunlight or acid fumes to prevent partial oxidation and to avoid
patches. |
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