Kalpazol Vinyl Sulphone Dyes

INTRODUCTION                                                                                                                         SHADE CARDS

VS Dyestuffs are Reactive Dyes possessing Vinyl Sulphone as the reactive group. In presence of Alkali, these dyes chemically react with the hydroxyl group of cellulose and form firm, convalent linkages. These dyes are versatile enough to suit different dyeing as well as in printing.

VS dyestuffs possess poor affinity for cellulosic fibers in absence of salt and alkalies. For this reasons, they are suitable on pad. Their substantivity can be increased by addition of Glauber's salt or common salt and alkali, making the dyestuff suitable on all conventional dyeing machines for loose marerial, yarn in hanks and packages and piece goods. The dyeing methods may therefore, be classified under the padding and exhaust processes, standing baths are not recommended, as in alkaline medium inactivation of the dyestuffs by reaction with water takes place as a side reaction.
The main features of VS dyes are:

1) Possess excellent brightness and good wet fastness.
2) They are dischargeable.
3) They are suitable for Exhaust & different pad dyeing methods and discharge printing.
4) Ease of washing off unfixed dyestuffs i.e. minimum staining of thr white ground in printing.
5) They are applicable at 40oC and 60oC.

Exhaust Dyeing
V.S. Brand : Exhaust Dyeing

In case of VS Turquoise Blue G, Soda Ash is used as an alkali and Dyeing is carried out at 80^oC. Common Salt should not be used.

Padding Process

Any conventional padding equipment could be used for dyeing with this method.It is preferable to have the size of the trough as small as possible.

(I)One bath pad Batch using Sodium Silicate.

Padding:

The well prepared fabric is padded at 60-70% expression for cotton and 80-90% expression for staple viscose fabric at 20-25^oC. The lower temperature is preferred on grounds of dye liquor stability.

Fixation:

After the padding is complete the batch is covered with polythene film to avoid localized evaporation of water and allowed to dwell for 24 hours.

(II) One bath Pad-Dry Steam Process

The process is carried out on machines consisting of a padder with drying unit attached and also a continuous steamer as normally used in printing.The pad Liquor consists of :

X g/l              Dyestuffs

100g/l            Urea

Y cc/l            Water

10 g/l            Mild Oxidising agent

10-20 g/l        Sodium Bicarbonate

The Material is padded at room temperature in the above liquor at a nip expression of 60-70%, dried at 60-80^oC and then fixed by steaming in the normal continuous steamer for 7-10 minutes at 100-103^oC.

(III) Two Bath Pad-Dry Steam Process

Pad the material through dyestuff solution at 25-30^oC & dry. After intermediate drying the goods are padded at Room temperature using :

250-300 g/l     Common Salt and

20 cc/l           Caustic Soda 71^oTw.

The dyestuff is fixed by steaming at 103-105^oC for 20-30 seconds. When longer steaming time of 90-120 seconds is given the amount of caustic soda solution should be reduced to 10 cc/litre. When working without intermediate drying the chemical padding should have 25% higher expression than dyestuff padding and chemical liquor should contain :

250-300 g/l     Common Salt

80 cc/l           Caustic Soda Solution 71^oTw.

20-25^oC         Padding Temp.

Steaming is carried out for 20-30 seconds at 103-105^oC. For longer steaming time of 100 secs. the amount of caustic soda is reduced to 20 cc/l (71^oTw).

(IV) Pad-Dry Thermofix process

In this process a padding machine with attached hot fuel and curing unit that allows treatment for 5 minutes are required.

The pad liqour consists of : (parts / 1000)

For inferior varities of cloth and on the drying equipments where fear of dyestuff migration is there, an addition of 5 to 10 g/l of Sodium alginate paste thickening to the padding liquor is necessary.

Fixation :

After treatment :

To obtain optimum fastness properties, irrespective of any dyeing temperature, alkali or dyestuff used, unfixed dyestuff must be washed out from the fibre.

This can be carried out on any suitable equipment such as Jigger, Winch or open width soaper.

The material is rinsed in cold water, then in cold water containing 2 cc/l acetic acid. This is followed by a rinse in hot water & finally soaped at boil in a bath containing 2 g/l anionic soap followed by hot & cold rinse.

Printing :

VS Dyes produce prints with excellent brightness as compared to those with other classes of dyestuffs. It is possible to get a variety of shades, as the colours are available in all hues.

There are two methods of direct printing of cellulosic fibers.

1) One phase printing

2) Two phase printing

In one phase printing method the alkali is added to the printing paste while in two phase printing paste is made without alkali and the prints are fixed by padding or dipping the printed fabric in an alkaline fixation liquor.

The prints can then be fixed under various steaming conditions.

Fixation :

1) One phase printing :

The printed and dried fabric is steamed with saturated steam at 103^oC for 10 to 15 minutes in a star ager for 5 - 7 minutes in a continuous steamer.

2) Two phase printing :

The printed and dried fabric is passed through a hot fixation bath, which is maintained at 95 - 100^oC, preferably with indirect heating arrangement to avoid dilution of the liquor.

The fixation bath consists of the following :

i) 200 gms/litre Glauber's Salt

   150 gms/litre Soda Ash

    50 gms/litre Potash

    25-30 gms/litre Caustic Soda (Solid)

The time required for fixation of the prints is 5-12 seconds. The prints are washed immediately after fixation without an intervening air passage.

ii) The printed and dried fabric is nip padded or stop padded with :

48-52^oBe.Sodium Silicate solution containing 4-6 cc/l Caustic Soda 38^oBe. The batch is well covered with plastic sheet and allowed to dwell for 16-20 hours. Then follow after treatment as mentioned earlier.

Washing Procedure

In order to obtain maximum wet-fastness properties, brightness and purity of shades with consistent dyeing results, it is essential to give a thorough 'Soaping' to clear-off unreached hydrolysed dye from the dyed fabric.

The dyed fabric is rinsed repeatedly in cold water to remove most of alkali, salt and unmixed dye present and rinse again in warm water not higher than 60^oC. Then run in a bath containing :

Anionic detergent - 1-2gms/litre for 15 minutes at the boil, then rinse in warm water (up to 60^oC) and finally in cold water.The most satisfactory results in Washing-off, particularly for piece goods, are obtained by employing an Open soaper or perforated Beam-washing machine. If such equipments are not available, conventional ones like Jig or Winch may be used. For yarn in the hank form open-vat is employed and for yarn in pakaged form the package-dyeing machine itself used.

Key to Abbreviations :
L           = Low
M          = Medium
H          = High
V           =Very High
+          =Suitable
(+)       = Fairly Suitable
-           = Not Suitable

 Dischargeability        :   G = Good,   F = Fair,   P = Poor

 Light                            :   1 to 8 in increasing order

 Washing & other       :   1 to 5 in increasing order

 Y          = Yellow

 O          = Orange

 R          = Red

 V          = Violet

 B          = Blue

 Br        = Brown

 Bl         = Black

 G          = Green