Products: VAT DYES / SAVVY THERENE & SAVVYNON
General
Savvy dyes are vat dyestuffs possessing outstanding all around fastness properties on cellulosic materials. These are supplied
in different forms such as U/C, H/C, Powder, Ultra Disperse, Micro fine etc., and they differ in tinctorial strength and
particle size.
Principle of Application :
Savvy dyestuff supplied in the above forms are insoluble in water. These dyestuffs are rendered soluble in to their water soluble
leuco compound by reduction with sodium hydrosulphite in the presence of caustic soda. Only in this form they are taken up by the
material to be dyed. The leuco form is reconverted to the original insoluble dyestuff by the oxidation proces these by fixing
the dyestuff on the fibre.
Procedure for dyeing:
(A) Exhaust Dyeing Process:
Indigold type of dyestuffs, suh as SAVVY Magenta B Pdr. ad SAVVY Pink R PDR. are to be vatted in concentrated vat only, where as
the other can also be vatted in the long loquor. While vatting ensure that the dyestuff has gone into solution completely.
Vatting is carried out as per table A.
After vatting the filtered leuco solution is poured through a muslin cloth into the dyebath previously set with the requisite
quantities of chemical as er table C or Table D and dyed as per the temperature and time prescribed.
(B) Padding Process:
This Process is generally used for dyeing fabric where better penetration and leveling is desired. Normlly, M/F and U/D forms
of Savvy dyestuffs are recommended for padding. Other forms can be used by the Vat-acid method. The Padded fabric is developed
by the Vat-acid method. The padded fabric is developed by the semi continuous or continuous method. The major sequence for
important padding processes are as follows :
1. Pad-dry (Optional) Jig develoment - Oxidase Soap :
In order to attain equillibrium between the dyestuff on the fibre and in the bath it is advisable to add some padding liquor to
the developing bath at the start Calculated by the following formula for the liquor ratio 1:3 to 1:5.
%shade X %Expression
10 ml. per litre
OR = padding solution to be added to the Jig bath
g/l padding solution X (%expression)²
100
padded faric is dyed in the jig using chemicals as per table B.
2. Pad-dry (optional) - Chemical pad - Steam - Rise - Oxidise - Soap :
The padded and dried goods are chemical padded using following solution for development of various depth of shade for 100% expression.
| 40 - 300 |
ml/ l |
Caustic Soda, 710Tw (32.5%) |
| 10 - 75 |
g / l |
Hydrosulphite of Soda |
| 25 - 50 |
g / l |
Glauber's Salt |
Incase of padded goods which are not dried intermediately, the expression of chemical pad is always maintained 30 - 40% higher
than the pigment pad and the quantities recommended above for 100% expression, in case of intermediate drying, is inscreased
proportionately.
OXIDATION:
After dyeing, the goods are freed from excess liquor by even squeezing or by hydro extraction and oxidised by one of the following
methods:
a. Alration - The material is hanged loosely in air for 30 - 45 minutes.
b. Chemical Oxidation - The material is treated for 15 - 20 minutes at 50º C in a bath clothing.
| i) 2 - 3 |
g / l Sodium Perborate OR |
| ii) 1 - 2 |
g / l Sodium Bichromate and 5 ml / l acetic acid (30%) OR |
| iii) 2 - 4 |
ml / l Hydrogen peroxide (130 vol.) OR |
The Material is then washed, soured in cold with 2 - 4 ml / l galial Acetic acid, rinsed well and is soaped at boil with
| 1 - 2 |
g / l Detergent |
| 1 - 2 |
g / l Soda ash |
for 10 Minutes and rinsed well in water.
NOTES:
- Use leveling agent when dyeing pale shade.
- Soap thoroughly at boil to produce stable shade.
- To produce black shade treat the dyeing after rinsing in sodium Hypocholorite soln. (1-1.5ºTw) for 30 minutes
at room temperature.
- Do not rinse before oxidation.
- Dyeings are sensitive to host and moisture.
- Not recommended for grey shades.
- Bichormate oxidation is not recommended.
ILLUSTRATION
The patterns illustrated in this card have been dyed on scoured unmercerised cotton yarn at 1:20 materal to liquor ration by
exhaust method as per the recommended recipe. The % depth refers to the pdr. and / or H / C brand except Green FFB where
Ultra conc. brand has been used.
FASTNESS RATING :
Light: 1 to 8 increasing order where 8 represents highest fastness.
WASHING & OTHER :
1 to 5 in increasing order whre 5 represents highest fastness.
This information is based on our state of knowledge and is intented to provide general notes on our products and their uses.
It should not therefore be construed as guaranteering specific proerties of the products described of the suitability for a
particular application. Any exisitng industrial property rights must be observed. The quality of our products is guaranted under
our General conditions of Sale.
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